/* Expands front end tree to back end RTL for GCC Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /* This file handles the generation of rtl code from tree structure above the level of expressions, using subroutines in exp*.c and emit-rtl.c. It also creates the rtl expressions for parameters and auto variables and has full responsibility for allocating stack slots. The functions whose names start with `expand_' are called by the parser to generate RTL instructions for various kinds of constructs. Some control and binding constructs require calling several such functions at different times. For example, a simple if-then is expanded by calling `expand_start_cond' (with the condition-expression as argument) before parsing the then-clause and calling `expand_end_cond' after parsing the then-clause. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "rtl.h" #include "tree.h" #include "tm_p.h" #include "flags.h" #include "except.h" #include "function.h" #include "insn-config.h" #include "expr.h" #include "libfuncs.h" #include "hard-reg-set.h" #include "loop.h" #include "recog.h" #include "machmode.h" #include "toplev.h" #include "output.h" #include "ggc.h" #include "langhooks.h" #include "predict.h" #include "optabs.h" #include "target.h" /* Assume that case vectors are not pc-relative. */ #ifndef CASE_VECTOR_PC_RELATIVE #define CASE_VECTOR_PC_RELATIVE 0 #endif /* Functions and data structures for expanding case statements. */ /* Case label structure, used to hold info on labels within case statements. We handle "range" labels; for a single-value label as in C, the high and low limits are the same. An AVL tree of case nodes is initially created, and later transformed to a list linked via the RIGHT fields in the nodes. Nodes with higher case values are later in the list. Switch statements can be output in one of two forms. A branch table is used if there are more than a few labels and the labels are dense within the range between the smallest and largest case value. If a branch table is used, no further manipulations are done with the case node chain. The alternative to the use of a branch table is to generate a series of compare and jump insns. When that is done, we use the LEFT, RIGHT, and PARENT fields to hold a binary tree. Initially the tree is totally unbalanced, with everything on the right. We balance the tree with nodes on the left having lower case values than the parent and nodes on the right having higher values. We then output the tree in order. */ struct case_node GTY(()) { struct case_node *left; /* Left son in binary tree */ struct case_node *right; /* Right son in binary tree; also node chain */ struct case_node *parent; /* Parent of node in binary tree */ tree low; /* Lowest index value for this label */ tree high; /* Highest index value for this label */ tree code_label; /* Label to jump to when node matches */ int balance; }; typedef struct case_node case_node; typedef struct case_node *case_node_ptr; /* These are used by estimate_case_costs and balance_case_nodes. */ /* This must be a signed type, and non-ANSI compilers lack signed char. */ static short cost_table_[129]; static int use_cost_table; static int cost_table_initialized; /* Special care is needed because we allow -1, but TREE_INT_CST_LOW is unsigned. */ #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)] /* Stack of control and binding constructs we are currently inside. These constructs begin when you call `expand_start_WHATEVER' and end when you call `expand_end_WHATEVER'. This stack records info about how the construct began that tells the end-function what to do. It also may provide information about the construct to alter the behavior of other constructs within the body. For example, they may affect the behavior of C `break' and `continue'. Each construct gets one `struct nesting' object. All of these objects are chained through the `all' field. `nesting_stack' points to the first object (innermost construct). The position of an entry on `nesting_stack' is in its `depth' field. Each type of construct has its own individual stack. For example, loops have `loop_stack'. Each object points to the next object of the same type through the `next' field. Some constructs are visible to `break' exit-statements and others are not. Which constructs are visible depends on the language. Therefore, the data structure allows each construct to be visible or not, according to the args given when the construct is started. The construct is visible if the `exit_label' field is non-null. In that case, the value should be a CODE_LABEL rtx. */ struct nesting GTY(()) { struct nesting *all; struct nesting *next; int depth; rtx exit_label; enum nesting_desc { COND_NESTING, LOOP_NESTING, BLOCK_NESTING, CASE_NESTING } desc; union nesting_u { /* For conds (if-then and if-then-else statements). */ struct nesting_cond { /* Label for the end of the if construct. There is none if EXITFLAG was not set and no `else' has been seen yet. */ rtx endif_label; /* Label for the end of this alternative. This may be the end of the if or the next else/elseif. */ rtx next_label; } GTY ((tag ("COND_NESTING"))) cond; /* For loops. */ struct nesting_loop { /* Label at the top of the loop; place to loop back to. */ rtx start_label; /* Label at the end of the whole construct. */ rtx end_label; /* Label for `continue' statement to jump to; this is in front of the stepper of the loop. */ rtx continue_label; } GTY ((tag ("LOOP_NESTING"))) loop; /* For variable binding contours. */ struct nesting_block { /* Sequence number of this binding contour within the function, in order of entry. */ int block_start_count; /* Nonzero => value to restore stack to on exit. */ rtx stack_level; /* The NOTE that starts this contour. Used by expand_goto to check whether the destination is within each contour or not. */ rtx first_insn; /* Innermost containing binding contour that has a stack level. */ struct nesting *innermost_stack_block; /* List of cleanups to be run on exit from this contour. This is a list of expressions to be evaluated. The TREE_PURPOSE of each link is the ..._DECL node which the cleanup pertains to. */ tree cleanups; /* List of cleanup-lists of blocks containing this block, as they were at the locus where this block appears. There is an element for each containing block, ordered innermost containing block first. The tail of this list can be 0, if all remaining elements would be empty lists. The element's TREE_VALUE is the cleanup-list of that block, which may be null. */ tree outer_cleanups; /* Chain of labels defined inside this binding contour. For contours that have stack levels or cleanups. */ struct label_chain *label_chain; /* Nonzero if this is associated with an EH region. */ int exception_region; /* The saved target_temp_slot_level from our outer block. We may reset target_temp_slot_level to be the level of this block, if that is done, target_temp_slot_level reverts to the saved target_temp_slot_level at the very end of the block. */ int block_target_temp_slot_level; /* True if we are currently emitting insns in an area of output code that is controlled by a conditional expression. This is used by the cleanup handling code to generate conditional cleanup actions. */ int conditional_code; /* A place to move the start of the exception region for any of the conditional cleanups, must be at the end or after the start of the last unconditional cleanup, and before any conditional branch points. */ rtx last_unconditional_cleanup; } GTY ((tag ("BLOCK_NESTING"))) block; /* For switch (C) or case (Pascal) statements, and also for dummies (see `expand_start_case_dummy'). */ struct nesting_case { /* The insn after which the case dispatch should finally be emitted. Zero for a dummy. */ rtx start; /* A list of case labels; it is first built as an AVL tree. During expand_end_case, this is converted to a list, and may be rearranged into a nearly balanced binary tree. */ struct case_node *case_list; /* Label to jump to if no case matches. */ tree default_label; /* The expression to be dispatched on. */ tree index_expr; /* Type that INDEX_EXPR should be converted to. */ tree nominal_type; /* Name of this kind of statement, for warnings. */ const char *printname; /* Used to save no_line_numbers till we see the first case label. We set this to -1 when we see the first case label in this case statement. */ int line_number_status; } GTY ((tag ("CASE_NESTING"))) case_stmt; } GTY ((desc ("%1.desc"))) data; }; /* Allocate and return a new `struct nesting'. */ #define ALLOC_NESTING() ggc_alloc (sizeof (struct nesting)) /* Pop the nesting stack element by element until we pop off the element which is at the top of STACK. Update all the other stacks, popping off elements from them as we pop them from nesting_stack. */ #define POPSTACK(STACK) \ do { struct nesting *target = STACK; \ struct nesting *this; \ do { this = nesting_stack; \ if (loop_stack == this) \ loop_stack = loop_stack->next; \ if (cond_stack == this) \ cond_stack = cond_stack->next; \ if (block_stack == this) \ block_stack = block_stack->next; \ if (stack_block_stack == this) \ stack_block_stack = stack_block_stack->next; \ if (case_stack == this) \ case_stack = case_stack->next; \ nesting_depth = nesting_stack->depth - 1; \ nesting_stack = this->all; } \ while (this != target); } while (0) /* In some cases it is impossible to generate code for a forward goto until the label definition is seen. This happens when it may be necessary for the goto to reset the stack pointer: we don't yet know how to do that. So expand_goto puts an entry on this fixup list. Each time a binding contour that resets the stack is exited, we check each fixup. If the target label has now been defined, we can insert the proper code. */ struct goto_fixup GTY(()) { /* Points to following fixup. */ struct goto_fixup *next; /* Points to the insn before the jump insn. If more code must be inserted, it goes after this insn. */ rtx before_jump; /* The LABEL_DECL that this jump is jumping to, or 0 for break, continue or return. */ tree target; /* The BLOCK for the place where this goto was found. */ tree context; /* The CODE_LABEL rtx that this is jumping to. */ rtx target_rtl; /* Number of binding contours started in current function before the label reference. */ int block_start_count; /* The outermost stack level that should be restored for this jump. Each time a binding contour that resets the stack is exited, if the target label is *not* yet defined, this slot is updated. */ rtx stack_level; /* List of lists of cleanup expressions to be run by this goto. There is one element for each block that this goto is within. The tail of this list can be 0, if all remaining elements would be empty. The TREE_VALUE contains the cleanup list of that block as of the time this goto was seen. The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */ tree cleanup_list_list; }; /* Within any binding contour that must restore a stack level, all labels are recorded with a chain of these structures. */ struct label_chain GTY(()) { /* Points to following fixup. */ struct label_chain *next; tree label; }; struct stmt_status GTY(()) { /* Chain of all pending binding contours. */ struct nesting * x_block_stack; /* If any new stacks are added here, add them to POPSTACKS too. */ /* Chain of all pending binding contours that restore stack levels or have cleanups. */ struct nesting * x_stack_block_stack; /* Chain of all pending conditional statements. */ struct nesting * x_cond_stack; /* Chain of all pending loops. */ struct nesting * x_loop_stack; /* Chain of all pending case or switch statements. */ struct nesting * x_case_stack; /* Separate chain including all of the above, chained through the `all' field. */ struct nesting * x_nesting_stack; /* Number of entries on nesting_stack now. */ int x_nesting_depth; /* Number of binding contours started so far in this function. */ int x_block_start_count; /* Each time we expand an expression-statement, record the expr's type and its RTL value here. */ tree x_last_expr_type; rtx x_last_expr_value; rtx x_last_expr_alt_rtl; /* Nonzero if within a ({...}) grouping, in which case we must always compute a value for each expr-stmt in case it is the last one. */ int x_expr_stmts_for_value; /* Location of last line-number note, whether we actually emitted it or not. */ location_t x_emit_locus; struct goto_fixup *x_goto_fixup_chain; }; #define block_stack (cfun->stmt->x_block_stack) #define stack_block_stack (cfun->stmt->x_stack_block_stack) #define cond_stack (cfun->stmt->x_cond_stack) #define loop_stack (cfun->stmt->x_loop_stack) #define case_stack (cfun->stmt->x_case_stack) #define nesting_stack (cfun->stmt->x_nesting_stack) #define nesting_depth (cfun->stmt->x_nesting_depth) #define current_block_start_count (cfun->stmt->x_block_start_count) #define last_expr_type (cfun->stmt->x_last_expr_type) #define last_expr_value (cfun->stmt->x_last_expr_value) #define last_expr_alt_rtl (cfun->stmt->x_last_expr_alt_rtl) #define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value) #define emit_locus (cfun->stmt->x_emit_locus) #define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain) /* Nonzero if we are using EH to handle cleanups. */ static int using_eh_for_cleanups_p = 0; static int n_occurrences (int, const char *); static bool decl_conflicts_with_clobbers_p (tree, const HARD_REG_SET); static void expand_goto_internal (tree, rtx, rtx); static int expand_fixup (tree, rtx, rtx); static rtx expand_nl_handler_label (rtx, rtx); static void expand_nl_goto_receiver (void); static void expand_nl_goto_receivers (struct nesting *); static void fixup_gotos (struct nesting *, rtx, tree, rtx, int); static bool check_operand_nalternatives (tree, tree); static bool check_unique_operand_names (tree, tree); static char *resolve_operand_name_1 (char *, tree, tree); static void expand_null_return_1 (rtx); static enum br_predictor return_prediction (rtx); static rtx shift_return_value (rtx); static void expand_value_return (rtx); static int tail_recursion_args (tree, tree); static void expand_cleanups (tree, int, int); static void check_seenlabel (void); static void do_jump_if_equal (rtx, rtx, rtx, int); static int estimate_case_costs (case_node_ptr); static bool same_case_target_p (rtx, rtx); static void strip_default_case_nodes (case_node_ptr *, rtx); static bool lshift_cheap_p (void); static int case_bit_test_cmp (const void *, const void *); static void emit_case_bit_tests (tree, tree, tree, tree, case_node_ptr, rtx); static void group_case_nodes (case_node_ptr); static void balance_case_nodes (case_node_ptr *, case_node_ptr); static int node_has_low_bound (case_node_ptr, tree); static int node_has_high_bound (case_node_ptr, tree); static int node_is_bounded (case_node_ptr, tree); static void emit_jump_if_reachable (rtx); static void emit_case_nodes (rtx, case_node_ptr, rtx, tree); static struct case_node *case_tree2list (case_node *, case_node *); void using_eh_for_cleanups (void) { using_eh_for_cleanups_p = 1; } void init_stmt_for_function (void) { cfun->stmt = ggc_alloc_cleared (sizeof (struct stmt_status)); } /* Record the current file and line. Called from emit_line_note. */ void set_file_and_line_for_stmt (location_t location) { /* If we're outputting an inline function, and we add a line note, there may be no CFUN->STMT information. So, there's no need to update it. */ if (cfun->stmt) emit_locus = location; } /* Emit a no-op instruction. */ void emit_nop (void) { rtx last_insn; last_insn = get_last_insn (); if (!optimize && (GET_CODE (last_insn) == CODE_LABEL || (GET_CODE (last_insn) == NOTE && prev_real_insn (last_insn) == 0))) emit_insn (gen_nop ()); } /* Return the rtx-label that corresponds to a LABEL_DECL, creating it if necessary. */ rtx label_rtx (tree label) { if (TREE_CODE (label) != LABEL_DECL) abort (); if (!DECL_RTL_SET_P (label)) SET_DECL_RTL (label, gen_label_rtx ()); return DECL_RTL (label); } /* As above, but also put it on the forced-reference list of the function that contains it. */ rtx force_label_rtx (tree label) { rtx ref = label_rtx (label); tree function = decl_function_context (label); struct function *p; if (!function) abort (); if (function != current_function_decl && function != inline_function_decl) p = find_function_data (function); else p = cfun; p->expr->x_forced_labels = gen_rtx_EXPR_LIST (VOIDmode, ref, p->expr->x_forced_labels); return ref; } /* Add an unconditional jump to LABEL as the next sequential instruction. */ void emit_jump (rtx label) { do_pending_stack_adjust (); emit_jump_insn (gen_jump (label)); emit_barrier (); } /* Emit code to jump to the address specified by the pointer expression EXP. */ void expand_computed_goto (tree exp) { rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0); x = convert_memory_address (Pmode, x); emit_queue (); if (! cfun->computed_goto_common_label) { cfun->computed_goto_common_reg = copy_to_mode_reg (Pmode, x); cfun->computed_goto_common_label = gen_label_rtx (); do_pending_stack_adjust (); emit_label (cfun->computed_goto_common_label); emit_indirect_jump (cfun->computed_goto_common_reg); current_function_has_computed_jump = 1; } else { emit_move_insn (cfun->computed_goto_common_reg, x); emit_jump (cfun->computed_goto_common_label); } } /* Handle goto statements and the labels that they can go to. */ /* Specify the location in the RTL code of a label LABEL, which is a LABEL_DECL tree node. This is used for the kind of label that the user can jump to with a goto statement, and for alternatives of a switch or case statement. RTL labels generated for loops and conditionals don't go through here; they are generated directly at the RTL level, by other functions below. Note that this has nothing to do with defining label *names*. Languages vary in how they do that and what that even means. */ void expand_label (tree label) { struct label_chain *p; do_pending_stack_adjust (); emit_label (label_rtx (label)); if (DECL_NAME (label)) LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label)); if (stack_block_stack != 0) { p = ggc_alloc (sizeof (struct label_chain)); p->next = stack_block_stack->data.block.label_chain; stack_block_stack->data.block.label_chain = p; p->label = label; } } /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos from nested functions. */ void declare_nonlocal_label (tree label) { rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0); nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels); LABEL_PRESERVE_P (label_rtx (label)) = 1; if (nonlocal_goto_handler_slots == 0) { emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, PREV_INSN (tail_recursion_reentry)); } nonlocal_goto_handler_slots = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots); } /* Generate RTL code for a `goto' statement with target label LABEL. LABEL should be a LABEL_DECL tree node that was or will later be defined with `expand_label'. */ void expand_goto (tree label) { tree context; /* Check for a nonlocal goto to a containing function. */ context = decl_function_context (label); if (context != 0 && context != current_function_decl) { struct function *p = find_function_data (context); rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label)); rtx handler_slot, static_chain, save_area, insn; tree link; /* Find the corresponding handler slot for this label. */ handler_slot = p->x_nonlocal_goto_handler_slots; for (link = p->x_nonlocal_labels; TREE_VALUE (link) != label; link = TREE_CHAIN (link)) handler_slot = XEXP (handler_slot, 1); handler_slot = XEXP (handler_slot, 0); p->has_nonlocal_label = 1; current_function_has_nonlocal_goto = 1; LABEL_REF_NONLOCAL_P (label_ref) = 1; /* Copy the rtl for the slots so that they won't be shared in case the virtual stack vars register gets instantiated differently in the parent than in the child. */ static_chain = copy_to_reg (lookup_static_chain (label)); /* Get addr of containing function's current nonlocal goto handler, which will do any cleanups and then jump to the label. */ handler_slot = copy_to_reg (replace_rtx (copy_rtx (handler_slot), virtual_stack_vars_rtx, static_chain)); /* Get addr of containing function's nonlocal save area. */ save_area = p->x_nonlocal_goto_stack_level; if (save_area) save_area = replace_rtx (copy_rtx (save_area), virtual_stack_vars_rtx, static_chain); #if HAVE_nonlocal_goto if (HAVE_nonlocal_goto) emit_insn (gen_nonlocal_goto (static_chain, handler_slot, save_area, label_ref)); else #endif { emit_insn (gen_rtx_CLOBBER (VOIDmode, gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)))); emit_insn (gen_rtx_CLOBBER (VOIDmode, gen_rtx_MEM (BLKmode, hard_frame_pointer_rtx))); /* Restore frame pointer for containing function. This sets the actual hard register used for the frame pointer to the location of the function's incoming static chain info. The non-local goto handler will then adjust it to contain the proper value and reload the argument pointer, if needed. */ emit_move_insn (hard_frame_pointer_rtx, static_chain); emit_stack_restore (SAVE_NONLOCAL, save_area, NULL_RTX); /* USE of hard_frame_pointer_rtx added for consistency; not clear if really needed. */ emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx)); emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx)); emit_indirect_jump (handler_slot); } /* Search backwards to the jump insn and mark it as a non-local goto. */ for (insn = get_last_insn (); insn; insn = PREV_INSN (insn)) { if (GET_CODE (insn) == JUMP_INSN) { REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO, const0_rtx, REG_NOTES (insn)); break; } else if (GET_CODE (insn) == CALL_INSN) break; } } else expand_goto_internal (label, label_rtx (label), NULL_RTX); } /* Generate RTL code for a `goto' statement with target label BODY. LABEL should be a LABEL_REF. LAST_INSN, if non-0, is the rtx we should consider as the last insn emitted (for the purposes of cleaning up a return). */ static void expand_goto_internal (tree body, rtx label, rtx last_insn) { struct nesting *block; rtx stack_level = 0; if (GET_CODE (label) != CODE_LABEL) abort (); /* If label has already been defined, we can tell now whether and how we must alter the stack level. */ if (PREV_INSN (label) != 0) { /* Find the innermost pending block that contains the label. (Check containment by comparing insn-uids.) Then restore the outermost stack level within that block, and do cleanups of all blocks contained in it. */ for (block = block_stack; block; block = block->next) { if (INSN_UID (block->data.block.first_insn) < INSN_UID (label)) break; if (block->data.block.stack_level != 0) stack_level = block->data.block.stack_level; /* Execute the cleanups for blocks we are exiting. */ if (block->data.block.cleanups != 0) { expand_cleanups (block->data.block.cleanups, 1, 1); do_pending_stack_adjust (); } } if (stack_level) { /* Ensure stack adjust isn't done by emit_jump, as this would clobber the stack pointer. This one should be deleted as dead by flow. */ clear_pending_stack_adjust (); do_pending_stack_adjust (); /* Don't do this adjust if it's to the end label and this function is to return with a depressed stack pointer. */ if (label == return_label && (((TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE) && (TYPE_RETURNS_STACK_DEPRESSED (TREE_TYPE (current_function_decl)))))) ; else emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX); } if (body != 0 && DECL_TOO_LATE (body)) error ("jump to `%s' invalidly jumps into binding contour", IDENTIFIER_POINTER (DECL_NAME (body))); } /* Label not yet defined: may need to put this goto on the fixup list. */ else if (! expand_fixup (body, label, last_insn)) { /* No fixup needed. Record that the label is the target of at least one goto that has no fixup. */ if (body != 0) TREE_ADDRESSABLE (body) = 1; } emit_jump (label); } /* Generate if necessary a fixup for a goto whose target label in tree structure (if any) is TREE_LABEL and whose target in rtl is RTL_LABEL. If LAST_INSN is nonzero, we pretend that the jump appears after insn LAST_INSN instead of at the current point in the insn stream. The fixup will be used later to insert insns just before the goto. Those insns will restore the stack level as appropriate for the target label, and will (in the case of C++) also invoke any object destructors which have to be invoked when we exit the scopes which are exited by the goto. Value is nonzero if a fixup is made. */ static int expand_fixup (tree tree_label, rtx rtl_label, rtx last_insn) { struct nesting *block, *end_block; /* See if we can recognize which block the label will be output in. This is possible in some very common cases. If we succeed, set END_BLOCK to that block. Otherwise, set it to 0. */ if (cond_stack && (rtl_label == cond_stack->data.cond.endif_label || rtl_label == cond_stack->data.cond.next_label)) end_block = cond_stack; /* If we are in a loop, recognize certain labels which are likely targets. This reduces the number of fixups we need to create. */ else if (loop_stack && (rtl_label == loop_stack->data.loop.start_label || rtl_label == loop_stack->data.loop.end_label || rtl_label == loop_stack->data.loop.continue_label)) end_block = loop_stack; else end_block = 0; /* Now set END_BLOCK to the binding level to which we will return. */ if (end_block) { struct nesting *next_block = end_block->all; block = block_stack; /* First see if the END_BLOCK is inside the innermost binding level. If so, then no cleanups or stack levels are relevant. */ while (next_block && next_block != block) next_block = next_block->all; if (next_block) return 0; /* Otherwise, set END_BLOCK to the innermost binding level which is outside the relevant control-structure nesting. */ next_block = block_stack->next; for (block = block_stack; block != end_block; block = block->all) if (block == next_block) next_block = next_block->next; end_block = next_block; } /* Does any containing block have a stack level or cleanups? If not, no fixup is needed, and that is the normal case (the only case, for standard C). */ for (block = block_stack; block != end_block; block = block->next) if (block->data.block.stack_level != 0 || block->data.block.cleanups != 0) break; if (block != end_block) { /* Ok, a fixup is needed. Add a fixup to the list of such. */ struct goto_fixup *fixup = ggc_alloc (sizeof (struct goto_fixup)); /* In case an old stack level is restored, make sure that comes after any pending stack adjust. */ /* ?? If the fixup isn't to come at the present position, doing the stack adjust here isn't useful. Doing it with our settings at that location isn't useful either. Let's hope someone does it! */ if (last_insn == 0) do_pending_stack_adjust (); fixup->target = tree_label; fixup->target_rtl = rtl_label; /* Create a BLOCK node and a corresponding matched set of NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at this point. The notes will encapsulate any and all fixup code which we might later insert at this point in the insn stream. Also, the BLOCK node will be the parent (i.e. the `SUPERBLOCK') of any other BLOCK nodes which we might create later on when we are expanding the fixup code. Note that optimization passes (including expand_end_loop) might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED as a placeholder. */ { rtx original_before_jump = last_insn ? last_insn : get_last_insn (); rtx start; rtx end; tree block; block = make_node (BLOCK); TREE_USED (block) = 1; if (!cfun->x_whole_function_mode_p) (*lang_hooks.decls.insert_block) (block); else { BLOCK_CHAIN (block) = BLOCK_CHAIN (DECL_INITIAL (current_function_decl)); BLOCK_CHAIN (DECL_INITIAL (current_function_decl)) = block; } start_sequence (); start = emit_note (NOTE_INSN_BLOCK_BEG); if (cfun->x_whole_function_mode_p) NOTE_BLOCK (start) = block; fixup->before_jump = emit_note (NOTE_INSN_DELETED); end = emit_note (NOTE_INSN_BLOCK_END); if (cfun->x_whole_function_mode_p) NOTE_BLOCK (end) = block; fixup->context = block; end_sequence (); emit_insn_after (start, original_before_jump); } fixup->block_start_count = current_block_start_count; fixup->stack_level = 0; fixup->cleanup_list_list = ((block->data.block.outer_cleanups || block->data.block.cleanups) ? tree_cons (NULL_TREE, block->data.block.cleanups, block->data.block.outer_cleanups) : 0); fixup->next = goto_fixup_chain; goto_fixup_chain = fixup; } return block != 0; } /* Expand any needed fixups in the outputmost binding level of the function. FIRST_INSN is the first insn in the function. */ void expand_fixups (rtx first_insn) { fixup_gotos (NULL, NULL_RTX, NULL_TREE, first_insn, 0); } /* When exiting a binding contour, process all pending gotos requiring fixups. THISBLOCK is the structure that describes the block being exited. STACK_LEVEL is the rtx for the stack level to restore exiting this contour. CLEANUP_LIST is a list of expressions to evaluate on exiting this contour. FIRST_INSN is the insn that began this contour. Gotos that jump out of this contour must restore the stack level and do the cleanups before actually jumping. DONT_JUMP_IN positive means report error if there is a jump into this contour from before the beginning of the contour. This is also done if STACK_LEVEL is nonzero unless DONT_JUMP_IN is negative. */ static void fixup_gotos (struct nesting *thisblock, rtx stack_level, tree cleanup_list, rtx first_insn, int dont_jump_in) { struct goto_fixup *f, *prev; /* F is the fixup we are considering; PREV is the previous one. */ /* We run this loop in two passes so that cleanups of exited blocks are run first, and blocks that are exited are marked so afterwards. */ for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next) { /* Test for a fixup that is inactive because it is already handled. */ if (f->before_jump == 0) { /* Delete inactive fixup from the chain, if that is easy to do. */ if (prev != 0) prev->next = f->next; } /* Has this fixup's target label been defined? If so, we can finalize it. */ else if (PREV_INSN (f->target_rtl) != 0) { rtx cleanup_insns; /* If this fixup jumped into this contour from before the beginning of this contour, report an error. This code used to use the first non-label insn after f->target_rtl, but that's wrong since such can be added, by things like put_var_into_stack and have INSN_UIDs that are out of the range of the block. */ /* ??? Bug: this does not detect jumping in through intermediate blocks that have stack levels or cleanups. It detects only a problem with the innermost block around the label. */ if (f->target != 0 && (dont_jump_in > 0 || (dont_jump_in == 0 && stack_level) || cleanup_list) && INSN_UID (first_insn) < INSN_UID (f->target_rtl) && INSN_UID (first_insn) > INSN_UID (f->before_jump) && ! DECL_ERROR_ISSUED (f->target)) { error ("%Jlabel '%D' used before containing binding contour", f->target, f->target); /* Prevent multiple errors for one label. */ DECL_ERROR_ISSUED (f->target) = 1; } /* We will expand the cleanups into a sequence of their own and then later on we will attach this new sequence to the insn stream just ahead of the actual jump insn. */ start_sequence (); /* Temporarily restore the lexical context where we will logically be inserting the fixup code. We do this for the sake of getting the debugging information right. */ (*lang_hooks.decls.pushlevel) (0); (*lang_hooks.decls.set_block) (f->context); /* Expand the cleanups for blocks this jump exits. */ if (f->cleanup_list_list) { tree lists; for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists)) /* Marked elements correspond to blocks that have been closed. Do their cleanups. */ if (TREE_ADDRESSABLE (lists) && TREE_VALUE (lists) != 0) { expand_cleanups (TREE_VALUE (lists), 1, 1); /* Pop any pushes done in the cleanups, in case function is about to return. */ do_pending_stack_adjust (); } } /* Restore stack level for the biggest contour that this jump jumps out of. */ if (f->stack_level && ! (f->target_rtl == return_label && ((TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE) && (TYPE_RETURNS_STACK_DEPRESSED (TREE_TYPE (current_function_decl)))))) emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump); /* Finish up the sequence containing the insns which implement the necessary cleanups, and then attach that whole sequence to the insn stream just ahead of the actual jump insn. Attaching it at that point insures that any cleanups which are in fact implicit C++ object destructions (which must be executed upon leaving the block) appear (to the debugger) to be taking place in an area of the generated code where the object(s) being destructed are still "in scope". */ cleanup_insns = get_insns (); (*lang_hooks.decls.poplevel) (1, 0, 0); end_sequence (); emit_insn_after (cleanup_insns, f->before_jump); f->before_jump = 0; } } /* For any still-undefined labels, do the cleanups for this block now. We must do this now since items in the cleanup list may go out of scope when the block ends. */ for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next) if (f->before_jump != 0 && PREV_INSN (f->target_rtl) == 0 /* Label has still not appeared. If we are exiting a block with a stack level to restore, that started before the fixup, mark this stack level as needing restoration when the fixup is later finalized. */ && thisblock != 0 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it means the label is undefined. That's erroneous, but possible. */ && (thisblock->data.block.block_start_count <= f->block_start_count)) { tree lists = f->cleanup_list_list; rtx cleanup_insns; for (; lists; lists = TREE_CHAIN (lists)) /* If the following elt. corresponds to our containing block then the elt. must be for this block. */ if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups) { start_sequence (); (*lang_hooks.decls.pushlevel) (0); (*lang_hooks.decls.set_block) (f->context); expand_cleanups (TREE_VALUE (lists), 1, 1); do_pending_stack_adjust (); cleanup_insns = get_insns (); (*lang_hooks.decls.poplevel) (1, 0, 0); end_sequence (); if (cleanup_insns != 0) f->before_jump = emit_insn_after (cleanup_insns, f->before_jump); f->cleanup_list_list = TREE_CHAIN (lists); } if (stack_level) f->stack_level = stack_level; } } /* Return the number of times character C occurs in string S. */ static int n_occurrences (int c, const char *s) { int n = 0; while (*s) n += (*s++ == c); return n; } /* Generate RTL for an asm statement (explicit assembler code). STRING is a STRING_CST node containing the assembler code text, or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the insn is volatile; don't optimize it. */ void expand_asm (tree string, int vol) { rtx body; if (TREE_CODE (string) == ADDR_EXPR) string = TREE_OPERAND (string, 0); body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string)); MEM_VOLATILE_P (body) = vol; emit_insn (body); clear_last_expr (); } /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the OPERAND_NUMth output operand, indexed from zero. There are NINPUTS inputs and NOUTPUTS outputs to this extended-asm. Upon return, *ALLOWS_MEM will be TRUE iff the constraint allows the use of a memory operand. Similarly, *ALLOWS_REG will be TRUE iff the constraint allows the use of a register operand. And, *IS_INOUT will be true if the operand is read-write, i.e., if it is used as an input as well as an output. If *CONSTRAINT_P is not in canonical form, it will be made canonical. (Note that `+' will be replaced with `=' as part of this process.) Returns TRUE if all went well; FALSE if an error occurred. */ bool parse_output_constraint (const char **constraint_p, int operand_num, int ninputs, int noutputs, bool *allows_mem, bool *allows_reg, bool *is_inout) { const char *constraint = *constraint_p; const char *p; /* Assume the constraint doesn't allow the use of either a register or memory. */ *allows_mem = false; *allows_reg = false; /* Allow the `=' or `+' to not be at the beginning of the string, since it wasn't explicitly documented that way, and there is a large body of code that puts it last. Swap the character to the front, so as not to uglify any place else. */ p = strchr (constraint, '='); if (!p) p = strchr (constraint, '+'); /* If the string doesn't contain an `=', issue an error message. */ if (!p) { error ("output operand constraint lacks `='"); return false; } /* If the constraint begins with `+', then the operand is both read from and written to. */ *is_inout = (*p == '+'); /* Canonicalize the output constraint so that it begins with `='. */ if (p != constraint || is_inout) { char *buf; size_t c_len = strlen (constraint); if (p != constraint) warning ("output constraint `%c' for operand %d is not at the beginning", *p, operand_num); /* Make a copy of the constraint. */ buf = alloca (c_len + 1); strcpy (buf, constraint); /* Swap the first character and the `=' or `+'. */ buf[p - constraint] = buf[0]; /* Make sure the first character is an `='. (Until we do this, it might be a `+'.) */ buf[0] = '='; /* Replace the constraint with the canonicalized string. */ *constraint_p = ggc_alloc_string (buf, c_len); constraint = *constraint_p; } /* Loop through the constraint string. */ for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p)) switch (*p) { case '+': case '=': error ("operand constraint contains incorrectly positioned '+' or '='"); return false; case '%': if (operand_num + 1 == ninputs + noutputs) { error ("`%%' constraint used with last operand"); return false; } break; case 'V': case 'm': case 'o': *allows_mem = true; break; case '?': case '!': case '*': case '&': case '#': case 'E': case 'F': case 'G': case 'H': case 's': case 'i': case 'n': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N': case 'O': case 'P': case ',': break; case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': case '[': error ("matching constraint not valid in output operand"); return false; case '<': case '>': /* ??? Before flow, auto inc/dec insns are not supposed to exist, excepting those that expand_call created. So match memory and hope. */ *allows_mem = true; break; case 'g': case 'X': *allows_reg = true; *allows_mem = true; break; case 'p': case 'r': *allows_reg = true; break; default: if (!ISALPHA (*p)) break; if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS) *allows_reg = true; #ifdef EXTRA_CONSTRAINT_STR else if (EXTRA_ADDRESS_CONSTRAINT (*p, p)) *allows_reg = true; else if (EXTRA_MEMORY_CONSTRAINT (*p, p)) *allows_mem = true; else { /* Otherwise we can't assume anything about the nature of the constraint except that it isn't purely registers. Treat it like "g" and hope for the best. */ *allows_reg = true; *allows_mem = true; } #endif break; } return true; } /* Similar, but for input constraints. */ bool parse_input_constraint (const char **constraint_p, int input_num, int ninputs, int noutputs, int ninout, const char * const * constraints, bool *allows_mem, bool *allows_reg) { const char *constraint = *constraint_p; const char *orig_constraint = constraint; size_t c_len = strlen (constraint); size_t j; bool saw_match = false; /* Assume the constraint doesn't allow the use of either a register or memory. */ *allows_mem = false; *allows_reg = false; /* Make sure constraint has neither `=', `+', nor '&'. */ for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j)) switch (constraint[j]) { case '+': case '=': case '&': if (constraint == orig_constraint) { error ("input operand constraint contains `%c'", constraint[j]); return false; } break; case '%': if (constraint == orig_constraint && input_num + 1 == ninputs - ninout) { error ("`%%' constraint used with last operand"); return false; } break; case 'V': case 'm': case 'o': *allows_mem = true; break; case '<': case '>': case '?': case '!': case '*': case '#': case 'E': case 'F': case 'G': case 'H': case 's': case 'i': case 'n': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N': case 'O': case 'P': case ',': break; /* Whether or not a numeric constraint allows a register is decided by the matching constraint, and so there is no need to do anything special with them. We must handle them in the default case, so that we don't unnecessarily force operands to memory. */ case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': { char *end; unsigned long match; saw_match = true; match = strtoul (constraint + j, &end, 10); if (match >= (unsigned long) noutputs) { error ("matching constraint references invalid operand number"); return false; } /* Try and find the real constraint for this dup. Only do this if the matching constraint is the only alternative. */ if (*end == '\0' && (j == 0 || (j == 1 && constraint[0] == '%'))) { constraint = constraints[match]; *constraint_p = constraint; c_len = strlen (constraint); j = 0; /* ??? At the end of the loop, we will skip the first part of the matched constraint. This assumes not only that the other constraint is an output constraint, but also that the '=' or '+' come first. */ break; } else j = end - constraint; /* Anticipate increment at end of loop. */ j--; } /* Fall through. */ case 'p': case 'r': *allows_reg = true; break; case 'g': case 'X': *allows_reg = true; *allows_mem = true; break; default: if (! ISALPHA (constraint[j])) { error ("invalid punctuation `%c' in constraint", constraint[j]); return false; } if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j) != NO_REGS) *allows_reg = true; #ifdef EXTRA_CONSTRAINT_STR else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j)) *allows_reg = true; else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j)) *allows_mem = true; else { /* Otherwise we can't assume anything about the nature of the constraint except that it isn't purely registers. Treat it like "g" and hope for the best. */ *allows_reg = true; *allows_mem = true; } #endif break; } if (saw_match && !*allows_reg) warning ("matching constraint does not allow a register"); return true; } /* Check for overlap between registers marked in CLOBBERED_REGS and anything inappropriate in DECL. Emit error and return TRUE for error, FALSE for ok. */ static bool decl_conflicts_with_clobbers_p (tree decl, const HARD_REG_SET clobbered_regs) { /* Conflicts between asm-declared register variables and the clobber list are not allowed. */ if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL) && DECL_REGISTER (decl) && REG_P (DECL_RTL (decl)) && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER) { rtx reg = DECL_RTL (decl); unsigned int regno; for (regno = REGNO (reg); regno < (REGNO (reg) + HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg))); regno++) if (TEST_HARD_REG_BIT (clobbered_regs, regno)) { error ("asm-specifier for variable `%s' conflicts with asm clobber list", IDENTIFIER_POINTER (DECL_NAME (decl))); /* Reset registerness to stop multiple errors emitted for a single variable. */ DECL_REGISTER (decl) = 0; return true; } } return false; } /* Generate RTL for an asm statement with arguments. STRING is the instruction template. OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs. Each output or input has an expression in the TREE_VALUE and and a tree list in TREE_PURPOSE which in turn contains a constraint name in TREE_VALUE (or NULL_TREE) and a constraint string in TREE_PURPOSE. CLOBBERS is a list of STRING_CST nodes each naming a hard register that is clobbered by this insn. Not all kinds of lvalue that may appear in OUTPUTS can be stored directly. Some elements of OUTPUTS may be replaced with trees representing temporary values. The caller should copy those temporary values to the originally specified lvalues. VOL nonzero means the insn is volatile; don't optimize it. */ void expand_asm_operands (tree string, tree outputs, tree inputs, tree clobbers, int vol, location_t locus) { rtvec argvec, constraintvec; rtx body; int ninputs = list_length (inputs); int noutputs = list_length (outputs); int ninout; int nclobbers; HARD_REG_SET clobbered_regs; int clobber_conflict_found = 0; tree tail; tree t; int i; /* Vector of RTX's of evaluated output operands. */ rtx *output_rtx = alloca (noutputs * sizeof (rtx)); int *inout_opnum = alloca (noutputs * sizeof (int)); rtx *real_output_rtx = alloca (noutputs * sizeof (rtx)); enum machine_mode *inout_mode = alloca (noutputs * sizeof (enum machine_mode)); const char **constraints = alloca ((noutputs + ninputs) * sizeof (const char *)); int old_generating_concat_p = generating_concat_p; /* An ASM with no outputs needs to be treated as volatile, for now. */ if (noutputs == 0) vol = 1; if (! check_operand_nalternatives (outputs, inputs)) return; string = resolve_asm_operand_names (string, outputs, inputs); /* Collect constraints. */ i = 0; for (t = outputs; t ; t = TREE_CHAIN (t), i++) constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t))); for (t = inputs; t ; t = TREE_CHAIN (t), i++) constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t))); #ifdef MD_ASM_CLOBBERS /* Sometimes we wish to automatically clobber registers across an asm. Case in point is when the i386 backend moved from cc0 to a hard reg -- maintaining source-level compatibility means automatically clobbering the flags register. */ MD_ASM_CLOBBERS (clobbers); #endif /* Count the number of meaningful clobbered registers, ignoring what we would ignore later. */ nclobbers = 0; CLEAR_HARD_REG_SET (clobbered_regs); for (tail = clobbers; tail; tail = TREE_CHAIN (tail)) { const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail)); i = decode_reg_name (regname); if (i >= 0 || i == -4) ++nclobbers; else if (i == -2) error ("unknown register name `%s' in `asm'", regname); /* Mark clobbered registers. */ if (i >= 0) { /* Clobbering the PIC register is an error */ if (i == (int) PIC_OFFSET_TABLE_REGNUM) { error ("PIC register `%s' clobbered in `asm'", regname); return; } SET_HARD_REG_BIT (clobbered_regs, i); } } clear_last_expr (); /* First pass over inputs and outputs checks validity and sets mark_addressable if needed. */ ninout = 0; for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++) { tree val = TREE_VALUE (tail); tree type = TREE_TYPE (val); const char *constraint; bool is_inout; bool allows_reg; bool allows_mem; /* If there's an erroneous arg, emit no insn. */ if (type == error_mark_node) return; /* Try to parse the output constraint. If that fails, there's no point in going further. */ constraint = constraints[i]; if (!parse_output_constraint (&constraint, i, ninputs, noutputs, &allows_mem, &allows_reg, &is_inout)) return; if (! allows_reg && (allows_mem || is_inout || (DECL_P (val) && GET_CODE (DECL_RTL (val)) == REG && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))) (*lang_hooks.mark_addressable) (val); if (is_inout) ninout++; } ninputs += ninout; if (ninputs + noutputs > MAX_RECOG_OPERANDS) { error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS); return; } for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail)) { bool allows_reg, allows_mem; const char *constraint; /* If there's an erroneous arg, emit no insn, because the ASM_INPUT would get VOIDmode and that could cause a crash in reload. */ if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node) return; constraint = constraints[i + noutputs]; if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout, constraints, &allows_mem, &allows_reg)) return; if (! allows_reg && allows_mem) (*lang_hooks.mark_addressable) (TREE_VALUE (tail)); } /* Second pass evaluates arguments. */ ninout = 0; for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++) { tree val = TREE_VALUE (tail); tree type = TREE_TYPE (val); bool is_inout; bool allows_reg; bool allows_mem; rtx op; if (!parse_output_constraint (&constraints[i], i, ninputs, noutputs, &allows_mem, &allows_reg, &is_inout)) abort (); /* If an output operand is not a decl or indirect ref and our constraint allows a register, make a temporary to act as an intermediate. Make the asm insn write into that, then our caller will copy it to the real output operand. Likewise for promoted variables. */ generating_concat_p = 0; real_output_rtx[i] = NULL_RTX; if ((TREE_CODE (val) == INDIRECT_REF && allows_mem) || (DECL_P (val) && (allows_mem || GET_CODE (DECL_RTL (val)) == REG) && ! (GET_CODE (DECL_RTL (val)) == REG && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))) || ! allows_reg || is_inout) { op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE); if (GET_CODE (op) == MEM) op = validize_mem (op); if (! allows_reg && GET_CODE (op) != MEM) error ("output number %d not directly addressable", i); if ((! allows_mem && GET_CODE (op) == MEM) || GET_CODE (op) == CONCAT) { real_output_rtx[i] = protect_from_queue (op, 1); op = gen_reg_rtx (GET_MODE (op)); if (is_inout) emit_move_insn (op, real_output_rtx[i]); } } else { op = assign_temp (type, 0, 0, 1); op = validize_mem (op); TREE_VALUE (tail) = make_tree (type, op); } output_rtx[i] = op; generating_concat_p = old_generating_concat_p; if (is_inout) { inout_mode[ninout] = TYPE_MODE (type); inout_opnum[ninout++] = i; } if (decl_conflicts_with_clobbers_p (val, clobbered_regs)) clobber_conflict_found = 1; } /* Make vectors for the expression-rtx, constraint strings, and named operands. */ argvec = rtvec_alloc (ninputs); constraintvec = rtvec_alloc (ninputs); body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode : GET_MODE (output_rtx[0])), TREE_STRING_POINTER (string), empty_string, 0, argvec, constraintvec, locus.file, locus.line); MEM_VOLATILE_P (body) = vol; /* Eval the inputs and put them into ARGVEC. Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */ for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i) { bool allows_reg, allows_mem; const char *constraint; tree val, type; rtx op; constraint = constraints[i + noutputs]; if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout, constraints, &allows_mem, &allows_reg)) abort (); generating_concat_p = 0; val = TREE_VALUE (tail); type = TREE_TYPE (val); op = expand_expr (val, NULL_RTX, VOIDmode, (allows_mem && !allows_reg ? EXPAND_MEMORY : EXPAND_NORMAL)); /* Never pass a CONCAT to an ASM. */ if (GET_CODE (op) == CONCAT) op = force_reg (GET_MODE (op), op); else if (GET_CODE (op) == MEM) op = validize_mem (op); if (asm_operand_ok (op, constraint) <= 0) { if (allows_reg) op = force_reg (TYPE_MODE (type), op); else if (!allows_mem) warning ("asm operand %d probably doesn't match constraints", i + noutputs); else if (GET_CODE (op) == MEM) { /* We won't recognize either volatile memory or memory with a queued address as available a memory_operand at this point. Ignore it: clearly this *is* a memory. */ } else { warning ("use of memory input without lvalue in " "asm operand %d is deprecated", i + noutputs); if (CONSTANT_P (op)) { rtx mem = force_const_mem (TYPE_MODE (type), op); if (mem) op = validize_mem (mem); else op = force_reg (TYPE_MODE (type), op); } if (GET_CODE (op) == REG || GET_CODE (op) == SUBREG || GET_CODE (op) == ADDRESSOF || GET_CODE (op) == CONCAT) { tree qual_type = build_qualified_type (type, (TYPE_QUALS (type) | TYPE_QUAL_CONST)); rtx memloc = assign_temp (qual_type, 1, 1, 1); memloc = validize_mem (memloc); emit_move_insn (memloc, op); op = memloc; } } } generating_concat_p = old_generating_concat_p; ASM_OPERANDS_INPUT (body, i) = op; ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i) = gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]); if (decl_conflicts_with_clobbers_p (val, clobbered_regs)) clobber_conflict_found = 1; } /* Protect all the operands from the queue now that they have all been evaluated. */ generating_concat_p = 0; for (i = 0; i < ninputs - ninout; i++) ASM_OPERANDS_INPUT (body, i) = protect_from_queue (ASM_OPERANDS_INPUT (body, i), 0); for (i = 0; i < noutputs; i++) output_rtx[i] = protect_from_queue (output_rtx[i], 1); /* For in-out operands, copy output rtx to input rtx. */ for (i = 0; i < ninout; i++) { int j = inout_opnum[i]; char buffer[16]; ASM_OPERANDS_INPUT (body, ninputs - ninout + i) = output_rtx[j]; sprintf (buffer, "%d", j); ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i) = gen_rtx_ASM_INPUT (inout_mode[i], ggc_strdup (buffer)); } generating_concat_p = old_generating_concat_p; /* Now, for each output, construct an rtx (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER ARGVEC CONSTRAINTS OPNAMES)) If there is more than one, put them inside a PARALLEL. */ if (noutputs == 1 && nclobbers == 0) { ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[0]; emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body)); } else if (noutputs == 0 && nclobbers == 0) { /* No output operands: put in a raw ASM_OPERANDS rtx. */ emit_insn (body); } else { rtx obody = body; int num = noutputs; if (num == 0) num = 1; body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers)); /* For each output operand, store a SET. */ for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++) { XVECEXP (body, 0, i) = gen_rtx_SET (VOIDmode, output_rtx[i], gen_rtx_ASM_OPERANDS (GET_MODE (output_rtx[i]), TREE_STRING_POINTER (string), constraints[i], i, argvec, constraintvec, locus.file, locus.line)); MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol; } /* If there are no outputs (but there are some clobbers) store the bare ASM_OPERANDS into the PARALLEL. */ if (i == 0) XVECEXP (body, 0, i++) = obody; /* Store (clobber REG) for each clobbered register specified. */ for (tail = clobbers; tail; tail = TREE_CHAIN (tail)) { const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail)); int j = decode_reg_name (regname); rtx clobbered_reg; if (j < 0) { if (j == -3) /* `cc', which is not a register */ continue; if (j == -4) /* `memory', don't cache memory across asm */ { XVECEXP (body, 0, i++) = gen_rtx_CLOBBER (VOIDmode, gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode))); continue; } /* Ignore unknown register, error already signaled. */ continue; } /* Use QImode since that's guaranteed to clobber just one reg. */ clobbered_reg = gen_rtx_REG (QImode, j); /* Do sanity check for overlap between clobbers and respectively input and outputs that hasn't been handled. Such overlap should have been detected and reported above. */ if (!clobber_conflict_found) { int opno; /* We test the old body (obody) contents to avoid tripping over the under-construction body. */ for (opno = 0; opno < noutputs; opno++) if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno])) internal_error ("asm clobber conflict with output operand"); for (opno = 0; opno < ninputs - ninout; opno++) if (reg_overlap_mentioned_p (clobbered_reg, ASM_OPERANDS_INPUT (obody, opno))) internal_error ("asm clobber conflict with input operand"); } XVECEXP (body, 0, i++) = gen_rtx_CLOBBER (VOIDmode, clobbered_reg); } emit_insn (body); } /* For any outputs that needed reloading into registers, spill them back to where they belong. */ for (i = 0; i < noutputs; ++i) if (real_output_rtx[i]) emit_move_insn (real_output_rtx[i], output_rtx[i]); free_temp_slots (); } /* A subroutine of expand_asm_operands. Check that all operands have the same number of alternatives. Return true if so. */ static bool check_operand_nalternatives (tree outputs, tree inputs) { if (outputs || inputs) { tree tmp = TREE_PURPOSE (outputs ? outputs : inputs); int nalternatives = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp))); tree next = inputs; if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES) { error ("too many alternatives in `asm'"); return false; } tmp = outputs; while (tmp) { const char *constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp))); if (n_occurrences (',', constraint) != nalternatives) { error ("operand constraints for `asm' differ in number of alternatives"); return false; } if (TREE_CHAIN (tmp)) tmp = TREE_CHAIN (tmp); else tmp = next, next = 0; } } return true; } /* A subroutine of expand_asm_operands. Check that all operand names are unique. Return true if so. We rely on the fact that these names are identifiers, and so have been canonicalized by get_identifier, so all we need are pointer comparisons. */ static bool check_unique_operand_names (tree outputs, tree inputs) { tree i, j; for (i = outputs; i ; i = TREE_CHAIN (i)) { tree i_name = TREE_PURPOSE (TREE_PURPOSE (i)); if (! i_name) continue; for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j)) if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j)))) goto failure; } for (i = inputs; i ; i = TREE_CHAIN (i)) { tree i_name = TREE_PURPOSE (TREE_PURPOSE (i)); if (! i_name) continue; for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j)) if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j)))) goto failure; for (j = outputs; j ; j = TREE_CHAIN (j)) if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j)))) goto failure; } return true; failure: error ("duplicate asm operand name '%s'", TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i)))); return false; } /* A subroutine of expand_asm_operands. Resolve the names of the operands in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in STRING and in the constraints to those numbers. */ tree resolve_asm_operand_names (tree string, tree outputs, tree inputs) { char *buffer; char *p; const char *c; tree t; check_unique_operand_names (outputs, inputs); /* Substitute [] in input constraint strings. There should be no named operands in output constraints. */ for (t = inputs; t ; t = TREE_CHAIN (t)) { c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t))); if (strchr (c, '[') != NULL) { p = buffer = xstrdup (c); while ((p = strchr (p, '[')) != NULL) p = resolve_operand_name_1 (p, outputs, inputs); TREE_VALUE (TREE_PURPOSE (t)) = build_string (strlen (buffer), buffer); free (buffer); } } /* Now check for any needed substitutions in the template. */ c = TREE_STRING_POINTER (string); while ((c = strchr (c, '%')) != NULL) { if (c[1] == '[') break; else if (ISALPHA (c[1]) && c[2] == '[') break; else { c += 1; continue; } } if (c) { /* OK, we need to make a copy so we can perform the substitutions. Assume that we will not need extra space--we get to remove '[' and ']', which means we cannot have a problem until we have more than 999 operands. */ buffer = xstrdup (TREE_STRING_POINTER (string)); p = buffer + (c - TREE_STRING_POINTER (string)); while ((p = strchr (p, '%')) != NULL) { if (p[1] == '[') p += 1; else if (ISALPHA (p[1]) && p[2] == '[') p += 2; else { p += 1; continue; } p = resolve_operand_name_1 (p, outputs, inputs); } string = build_string (strlen (buffer), buffer); free (buffer); } return string; } /* A subroutine of resolve_operand_names. P points to the '[' for a potential named operand of the form []. In place, replace the name and brackets with a number. Return a pointer to the balance of the string after substitution. */ static char * resolve_operand_name_1 (char *p, tree outputs, tree inputs) { char *q; int op; tree t; size_t len; /* Collect the operand name. */ q = strchr (p, ']'); if (!q) { error ("missing close brace for named operand"); return strchr (p, '\0'); } len = q - p - 1; /* Resolve the name to a number. */ for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++) { tree name = TREE_PURPOSE (TREE_PURPOSE (t)); if (name) { const char *c = TREE_STRING_POINTER (name); if (strncmp (c, p + 1, len) == 0 && c[len] == '\0') goto found; } } for (t = inputs; t ; t = TREE_CHAIN (t), op++) { tree name = TREE_PURPOSE (TREE_PURPOSE (t)); if (name) { const char *c = TREE_STRING_POINTER (name); if (strncmp (c, p + 1, len) == 0 && c[len] == '\0') goto found; } } *q = '\0'; error ("undefined named operand '%s'", p + 1); op = 0; found: /* Replace the name with the number. Unfortunately, not all libraries get the return value of sprintf correct, so search for the end of the generated string by hand. */ sprintf (p, "%d", op); p = strchr (p, '\0'); /* Verify the no extra buffer space assumption. */ if (p > q) abort (); /* Shift the rest of the buffer down to fill the gap. */ memmove (p, q + 1, strlen (q + 1) + 1); return p; } /* Generate RTL to evaluate the expression EXP and remember it in case this is the VALUE in a ({... VALUE; }) constr. Provided just for backward-compatibility. expand_expr_stmt_value() should be used for new code. */ void expand_expr_stmt (tree exp) { expand_expr_stmt_value (exp, -1, 1); } /* Generate RTL to evaluate the expression EXP. WANT_VALUE tells whether to (1) save the value of the expression, (0) discard it or (-1) use expr_stmts_for_value to tell. The use of -1 is deprecated, and retained only for backward compatibility. */ void expand_expr_stmt_value (tree exp, int want_value, int maybe_last) { rtx value; tree type; rtx alt_rtl = NULL; if (want_value == -1) want_value = expr_stmts_for_value != 0; /* If -Wextra, warn about statements with no side effects, except for an explicit cast to void (e.g. for assert()), and except for last statement in ({...}) where they may be useful. */ if (! want_value && (expr_stmts_for_value == 0 || ! maybe_last) && exp != error_mark_node && warn_unused_value) { if (TREE_SIDE_EFFECTS (exp)) warn_if_unused_value (exp); else if (!VOID_TYPE_P (TREE_TYPE (exp))) warning ("%Hstatement with no effect", &emit_locus); } /* If EXP is of function type and we are expanding statements for value, convert it to pointer-to-function. */ if (want_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE) exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp); /* The call to `expand_expr' could cause last_expr_type and last_expr_value to get reset. Therefore, we set last_expr_value and last_expr_type *after* calling expand_expr. */ value = expand_expr_real (exp, want_value ? NULL_RTX : const0_rtx, VOIDmode, 0, &alt_rtl); type = TREE_TYPE (exp); /* If all we do is reference a volatile value in memory, copy it to a register to be sure it is actually touched. */ if (value && GET_CODE (value) == MEM && TREE_THIS_VOLATILE (exp)) { if (TYPE_MODE (type) == VOIDmode) ; else if (TYPE_MODE (type) != BLKmode) value = copy_to_reg (value); else { rtx lab = gen_label_rtx (); /* Compare the value with itself to reference it. */ emit_cmp_and_jump_insns (value, value, EQ, expand_expr (TYPE_SIZE (type), NULL_RTX, VOIDmode, 0), BLKmode, 0, lab); emit_label (lab); } } /* If this expression is part of a ({...}) and is in memory, we may have to preserve temporaries. */ preserve_temp_slots (value); /* Free any temporaries used to evaluate this expression. Any temporary used as a result of this expression will already have been preserved above. */ free_temp_slots (); if (want_value) { last_expr_value = value; last_expr_alt_rtl = alt_rtl; last_expr_type = type; } emit_queue (); } /* Warn if EXP contains any computations whose results are not used. Return 1 if a warning is printed; 0 otherwise. */ int warn_if_unused_value (tree exp) { if (TREE_USED (exp)) return 0; /* Don't warn about void constructs. This includes casting to void, void function calls, and statement expressions with a final cast to void. */ if (VOID_TYPE_P (TREE_TYPE (exp))) return 0; switch (TREE_CODE (exp)) { case PREINCREMENT_EXPR: case POSTINCREMENT_EXPR: case PREDECREMENT_EXPR: case POSTDECREMENT_EXPR: case MODIFY_EXPR: case INIT_EXPR: case TARGET_EXPR: case CALL_EXPR: case RTL_EXPR: case TRY_CATCH_EXPR: case WITH_CLEANUP_EXPR: case EXIT_EXPR: return 0; case BIND_EXPR: /* For a binding, warn if no side effect within it. */ return warn_if_unused_value (TREE_OPERAND (exp, 1)); case SAVE_EXPR: return warn_if_unused_value (TREE_OPERAND (exp, 1)); case TRUTH_ORIF_EXPR: case TRUTH_ANDIF_EXPR: /* In && or ||, warn if 2nd operand has no side effect. */ return warn_if_unused_value (TREE_OPERAND (exp, 1)); case COMPOUND_EXPR: if (TREE_NO_UNUSED_WARNING (exp)) return 0; if (warn_if_unused_value (TREE_OPERAND (exp, 0))) return 1; /* Let people do `(foo (), 0)' without a warning. */ if (TREE_CONSTANT (TREE_OPERAND (exp, 1))) return 0; return warn_if_unused_value (TREE_OPERAND (exp, 1)); case NOP_EXPR: case CONVERT_EXPR: case NON_LVALUE_EXPR: /* Don't warn about conversions not explicit in the user's program. */ if (TREE_NO_UNUSED_WARNING (exp)) return 0; /* Assignment to a cast usually results in a cast of a modify. Don't complain about that. There can be an arbitrary number of casts before the modify, so we must loop until we find the first non-cast expression and then test to see if that is a modify. */ { tree tem = TREE_OPERAND (exp, 0); while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR) tem = TREE_OPERAND (tem, 0); if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR || TREE_CODE (tem) == CALL_EXPR) return 0; } goto maybe_warn; case INDIRECT_REF: /* Don't warn about automatic dereferencing of references, since the user cannot control it. */ if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE) return warn_if_unused_value (TREE_OPERAND (exp, 0)); /* Fall through. */ default: /* Referencing a volatile value is a side effect, so don't warn. */ if ((DECL_P (exp) || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r') && TREE_THIS_VOLATILE (exp)) return 0; /* If this is an expression which has no operands, there is no value to be unused. There are no such language-independent codes, but front ends may define such. */ if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e' && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0) return 0; maybe_warn: /* If this is an expression with side effects, don't warn. */ if (TREE_SIDE_EFFECTS (exp)) return 0; warning ("%Hvalue computed is not used", &emit_locus); return 1; } } /* Clear out the memory of the last expression evaluated. */ void clear_last_expr (void) { last_expr_type = NULL_TREE; last_expr_value = NULL_RTX; last_expr_alt_rtl = NULL_RTX; } /* Begin a statement-expression, i.e., a series of statements which may return a value. Return the RTL_EXPR for this statement expr. The caller must save that value and pass it to expand_end_stmt_expr. If HAS_SCOPE is nonzero, temporaries created in the statement-expression are deallocated at the end of the expression. */ tree expand_start_stmt_expr (int has_scope) { tree t; /* Make the RTL_EXPR node temporary, not momentary, so that rtl_expr_chain doesn't become garbage. */ t = make_node (RTL_EXPR); do_pending_stack_adjust (); if (has_scope) start_sequence_for_rtl_expr (t); else start_sequence (); NO_DEFER_POP; expr_stmts_for_value++; return t; } /* Restore the previous state at the end of a statement that returns a value. Returns a tree node representing the statement's value and the insns to compute the value. The nodes of that expression have been freed by now, so we cannot use them. But we don't want to do that anyway; the expression has already been evaluated and now we just want to use the value. So generate a RTL_EXPR with the proper type and RTL value. If the last substatement was not an expression, return something with type `void'. */ tree expand_end_stmt_expr (tree t) { OK_DEFER_POP; if (! last_expr_value || ! last_expr_type) { last_expr_value = const0_rtx; last_expr_alt_rtl = NULL_RTX; last_expr_type = void_type_node; } else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value)) /* Remove any possible QUEUED. */ last_expr_value = protect_from_queue (last_expr_value, 0); emit_queue (); TREE_TYPE (t) = last_expr_type; RTL_EXPR_RTL (t) = last_expr_value; RTL_EXPR_ALT_RTL (t) = last_expr_alt_rtl; RTL_EXPR_SEQUENCE (t) = get_insns (); rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain); end_sequence (); /* Don't consider deleting this expr or containing exprs at tree level. */ TREE_SIDE_EFFECTS (t) = 1; /* Propagate volatility of the actual RTL expr. */ TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value); clear_last_expr (); expr_stmts_for_value--; return t; } /* Generate RTL for the start of an if-then. COND is the expression whose truth should be tested. If EXITFLAG is nonzero, this conditional is visible to `exit_something'. */ void expand_start_cond (tree cond, int exitflag) { struct nesting *thiscond = ALLOC_NESTING (); /* Make an entry on cond_stack for the cond we are entering. */ thiscond->desc = COND_NESTING; thiscond->next = cond_stack; thiscond->all = nesting_stack; thiscond->depth = ++nesting_depth; thiscond->data.cond.next_label = gen_label_rtx (); /* Before we encounter an `else', we don't need a separate exit label unless there are supposed to be exit statements to exit this conditional. */ thiscond->exit_label = exitflag ? gen_label_rtx () : 0; thiscond->data.cond.endif_label = thiscond->exit_label; cond_stack = thiscond; nesting_stack = thiscond; do_jump (cond, thiscond->data.cond.next_label, NULL_RTX); } /* Generate RTL between then-clause and the elseif-clause of an if-then-elseif-.... */ void expand_start_elseif (tree cond) { if (cond_stack->data.cond.endif_label == 0) cond_stack->data.cond.endif_label = gen_label_rtx (); emit_jump (cond_stack->data.cond.endif_label); emit_label (cond_stack->data.cond.next_label); cond_stack->data.cond.next_label = gen_label_rtx (); do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX); } /* Generate RTL between the then-clause and the else-clause of an if-then-else. */ void expand_start_else (void) { if (cond_stack->data.cond.endif_label == 0) cond_stack->data.cond.endif_label = gen_label_rtx (); emit_jump (cond_stack->data.cond.endif_label); emit_label (cond_stack->data.cond.next_label); cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */ } /* After calling expand_start_else, turn this "else" into an "else if" by providing another condition. */ void expand_elseif (tree cond) { cond_stack->data.cond.next_label = gen_label_rtx (); do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX); } /* Generate RTL for the end of an if-then. Pop the record for it off of cond_stack. */ void expand_end_cond (void) { struct nesting *thiscond = cond_stack; do_pending_stack_adjust (); if (thiscond->data.cond.next_label) emit_label (thiscond->data.cond.next_label); if (thiscond->data.cond.endif_label) emit_label (thiscond->data.cond.endif_label); POPSTACK (cond_stack); clear_last_expr (); } /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this loop should be exited by `exit_something'. This is a loop for which `expand_continue' will jump to the top of the loop. Make an entry on loop_stack to record the labels associated with this loop. */ struct nesting * expand_start_loop (int exit_flag) { struct nesting *thisloop = ALLOC_NESTING (); /* Make an entry on loop_stack for the loop we are entering. */ thisloop->desc = LOOP_NESTING; thisloop->next = loop_stack; thisloop->all = nesting_stack; thisloop->depth = ++nesting_depth; thisloop->data.loop.start_label = gen_label_rtx (); thisloop->data.loop.end_label = gen_label_rtx (); thisloop->data.loop.continue_label = thisloop->data.loop.start_label; thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0; loop_stack = thisloop; nesting_stack = thisloop; do_pending_stack_adjust (); emit_queue (); emit_note (NOTE_INSN_LOOP_BEG); emit_label (thisloop->data.loop.start_label); return thisloop; } /* Like expand_start_loop but for a loop where the continuation point (for expand_continue_loop) will be specified explicitly. */ struct nesting * expand_start_loop_continue_elsewhere (int exit_flag) { struct nesting *thisloop = expand_start_loop (exit_flag); loop_stack->data.loop.continue_label = gen_label_rtx (); return thisloop; } /* Begin a null, aka do { } while (0) "loop". But since the contents of said loop can still contain a break, we must frob the loop nest. */ struct nesting * expand_start_null_loop (void) { struct nesting *thisloop = ALLOC_NESTING (); /* Make an entry on loop_stack for the loop we are entering. */ thisloop->desc = LOOP_NESTING; thisloop->next = loop_stack; thisloop->all = nesting_stack; thisloop->depth = ++nesting_depth; thisloop->data.loop.start_label = emit_note (NOTE_INSN_DELETED); thisloop->data.loop.end_label = gen_label_rtx (); thisloop->data.loop.continue_label = thisloop->data.loop.end_label; thisloop->exit_label = thisloop->data.loop.end_label; loop_stack = thisloop; nesting_stack = thisloop; return thisloop; } /* Specify the continuation point for a loop started with expand_start_loop_continue_elsewhere. Use this at the point in the code to which a continue statement should jump. */ void expand_loop_continue_here (void) { do_pending_stack_adjust (); emit_note (NOTE_INSN_LOOP_CONT); emit_label (loop_stack->data.loop.continue_label); } /* Finish a loop. Generate a jump back to the top and the loop-exit label. Pop the block off of loop_stack. */ void expand_end_loop (void) { rtx start_label = loop_stack->data.loop.start_label; rtx etc_note; int eh_regions, debug_blocks; bool empty_test; /* Mark the continue-point at the top of the loop if none elsewhere. */ if (start_label == loop_stack->data.loop.continue_label) emit_note_before (NOTE_INSN_LOOP_CONT, start_label); do_pending_stack_adjust (); /* If the loop starts with a loop exit, roll that to the end where it will optimize together with the jump back. If the loop presently looks like this (in pseudo-C): LOOP_BEG start_label: if (test) goto end_label; LOOP_END_TOP_COND body; goto start_label; end_label: transform it to look like: LOOP_BEG goto start_label; top_label: body; start_label: if (test) goto end_label; goto top_label; end_label: We rely on the presence of NOTE_INSN_LOOP_END_TOP_COND to mark the end of the entry conditional. Without this, our lexical scan can't tell the difference between an entry conditional and a body conditional that exits the loop. Mistaking the two means that we can misplace the NOTE_INSN_LOOP_CONT note, which can screw up loop unrolling. Things will be oh so much better when loop optimization is done off of a proper control flow graph... */ /* Scan insns from the top of the loop looking for the END_TOP_COND note. */ empty_test = true; eh_regions = debug_blocks = 0; for (etc_note = start_label; etc_note ; etc_note = NEXT_INSN (etc_note)) if (GET_CODE (etc_note) == NOTE) { if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_END_TOP_COND) break; /* We must not walk into a nested loop. */ else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_BEG) { etc_note = NULL_RTX; break; } /* At the same time, scan for EH region notes, as we don't want to scrog region nesting. This shouldn't happen, but... */ else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_BEG) eh_regions++; else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_END) { if (--eh_regions < 0) /* We've come to the end of an EH region, but never saw the beginning of that region. That means that an EH region begins before the top of the loop, and ends in the middle of it. The existence of such a situation violates a basic assumption in this code, since that would imply that even when EH_REGIONS is zero, we might move code out of an exception region. */ abort (); } /* Likewise for debug scopes. In this case we'll either (1) move all of the notes if they are properly nested or (2) leave the notes alone and only rotate the loop at high optimization levels when we expect to scrog debug info. */ else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_BEG) debug_blocks++; else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_END) debug_blocks--; } else if (INSN_P (etc_note)) empty_test = false; if (etc_note && optimize && ! empty_test && eh_regions == 0 && (debug_blocks == 0 || optimize >= 2) && NEXT_INSN (etc_note) != NULL_RTX && ! any_condjump_p (get_last_insn ())) { /* We found one. Move everything from START to ETC to the end of the loop, and add a jump from the top of the loop. */ rtx top_label = gen_label_rtx (); rtx start_move = start_label; /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note, then we want to move this note also. */ if (GET_CODE (PREV_INSN (start_move)) == NOTE && NOTE_LINE_NUMBER (PREV_INSN (start_move)) == NOTE_INSN_LOOP_CONT) start_move = PREV_INSN (start_move); emit_label_before (top_label, start_move); /* Actually move the insns. If the debug scopes are nested, we can move everything at once. Otherwise we have to move them one by one and squeeze out the block notes. */ if (debug_blocks == 0) reorder_insns (start_move, etc_note, get_last_insn ()); else { rtx insn, next_insn; for (insn = start_move; insn; insn = next_insn) { /* Figure out which insn comes after this one. We have to do this before we move INSN. */ next_insn = (insn == etc_note ? NULL : NEXT_INSN (insn)); if (GET_CODE (insn) == NOTE && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END)) continue; reorder_insns (insn, insn, get_last_insn ()); } } /* Add the jump from the top of the loop. */ emit_jump_insn_before (gen_jump (start_label), top_label); emit_barrier_before (top_label); start_label = top_label; } emit_jump (start_label); emit_note (NOTE_INSN_LOOP_END); emit_label (loop_stack->data.loop.end_label); POPSTACK (loop_stack); clear_last_expr (); } /* Finish a null loop, aka do { } while (0). */ void expand_end_null_loop (void) { do_pending_stack_adjust (); emit_label (loop_stack->data.loop.end_label); POPSTACK (loop_stack); clear_last_expr (); } /* Generate a jump to the current loop's continue-point. This is usually the top of the loop, but may be specified explicitly elsewhere. If not currently inside a loop, return 0 and do nothing; caller will print an error message. */ int expand_continue_loop (struct nesting *whichloop) { /* Emit information for branch prediction. */ rtx note; if (flag_guess_branch_prob) { note = emit_note (NOTE_INSN_PREDICTION); NOTE_PREDICTION (note) = NOTE_PREDICT (PRED_CONTINUE, IS_TAKEN); } clear_last_expr (); if (whichloop == 0) whichloop = loop_stack; if (whichloop == 0) return 0; expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label, NULL_RTX); return 1; } /* Generate a jump to exit the current loop. If not currently inside a loop, return 0 and do nothing; caller will print an error message. */ int expand_exit_loop (struct nesting *whichloop) { clear_last_expr (); if (whichloop == 0) whichloop = loop_stack; if (whichloop == 0) return 0; expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX); return 1; } /* Generate a conditional jump to exit the current loop if COND evaluates to zero. If not currently inside a loop, return 0 and do nothing; caller will print an error message. */ int expand_exit_loop_if_false (struct nesting *whichloop, tree cond) { rtx label; clear_last_expr (); if (whichloop == 0) whichloop = loop_stack; if (whichloop == 0) return 0; if (integer_nonzerop (cond)) return 1; if (integer_zerop (cond)) return expand_exit_loop (whichloop); /* Check if we definitely won't need a fixup. */ if (whichloop == nesting_stack) { jumpifnot (cond, whichloop->data.loop.end_label); return 1; } /* In order to handle fixups, we actually create a conditional jump around an unconditional branch to exit the loop. If fixups are necessary, they go before the unconditional branch. */ label = gen_label_rtx (); jumpif (cond, label); expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX); emit_label (label); return 1; } /* Like expand_exit_loop_if_false except also emit a note marking the end of the conditional. Should only be used immediately after expand_loop_start. */ int expand_exit_loop_top_cond (struct nesting *whichloop, tree cond) { if (! expand_exit_loop_if_false (whichloop, cond)) return 0; emit_note (NOTE_INSN_LOOP_END_TOP_COND); return 1; } /* Return nonzero if we should preserve sub-expressions as separate pseudos. We never do so if we aren't optimizing. We always do so if -fexpensive-optimizations. Otherwise, we only do so if we are in the "early" part of a loop. I.e., the loop may still be a small one. */ int preserve_subexpressions_p (void) { rtx insn; if (flag_expensive_optimizations) return 1; if (optimize == 0 || cfun == 0 || cfun->stmt == 0 || loop_stack == 0) return 0; insn = get_last_insn_anywhere (); return (insn && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label) < n_non_fixed_regs * 3)); } /* Generate a jump to exit the current loop, conditional, binding contour or case statement. Not all such constructs are visible to this function, only those started with EXIT_FLAG nonzero. Individual languages use the EXIT_FLAG parameter to control which kinds of constructs you can exit this way. If not currently inside anything that can be exited, return 0 and do nothing; caller will print an error message. */ int expand_exit_something (void) { struct nesting *n; clear_last_expr (); for (n = nesting_stack; n; n = n->all) if (n->exit_label != 0) { expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX); return 1; } return 0; } /* Generate RTL to return from the current function, with no value. (That is, we do not do anything about returning any value.) */ void expand_null_return (void) { rtx last_insn; last_insn = get_last_insn (); /* If this function was declared to return a value, but we didn't, clobber the return registers so that they are not propagated live to the rest of the function. */ clobber_return_register (); expand_null_return_1 (last_insn); } /* Generate RTL to return directly from the current function. (That is, we bypass any return value.) */ void expand_naked_return (void) { rtx last_insn, end_label; last_insn = get_last_insn (); end_label = naked_return_label; clear_pending_stack_adjust (); do_pending_stack_adjust (); clear_last_expr (); if (end_label == 0) end_label = naked_return_label = gen_label_rtx (); expand_goto_internal (NULL_TREE, end_label, last_insn); } /* Try to guess whether the value of return means error code. */ static enum br_predictor return_prediction (rtx val) { /* Different heuristics for pointers and scalars. */ if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl)))) { /* NULL is usually not returned. */ if (val == const0_rtx) return PRED_NULL_RETURN; } else { /* Negative return values are often used to indicate errors. */ if (GET_CODE (val) == CONST_INT && INTVAL (val) < 0) return PRED_NEGATIVE_RETURN; /* Constant return values are also usually erors, zero/one often mean booleans so exclude them from the heuristics. */ if (CONSTANT_P (val) && (val != const0_rtx && val != const1_rtx)) return PRED_CONST_RETURN; } return PRED_NO_PREDICTION; } /* If the current function returns values in the most significant part of a register, shift return value VAL appropriately. The mode of the function's return type is known not to be BLKmode. */ static rtx shift_return_value (rtx val) { tree type; type = TREE_TYPE (DECL_RESULT (current_function_decl)); if (targetm.calls.return_in_msb (type)) { rtx target; HOST_WIDE_INT shift; target = DECL_RTL (DECL_RESULT (current_function_decl)); shift = (GET_MODE_BITSIZE (GET_MODE (target)) - BITS_PER_UNIT * int_size_in_bytes (type)); if (shift > 0) val = expand_binop (GET_MODE (target), ashl_optab, gen_lowpart (GET_MODE (target), val), GEN_INT (shift), target, 1, OPTAB_WIDEN); } return val; } /* Generate RTL to return from the current function, with value VAL. */ static void expand_value_return (rtx val) { rtx last_insn; rtx return_reg; enum br_predictor pred; if (flag_guess_branch_prob && (pred = return_prediction (val)) != PRED_NO_PREDICTION) { /* Emit information for branch prediction. */ rtx note; note = emit_note (NOTE_INSN_PREDICTION); NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN); } last_insn = get_last_insn (); return_reg = DECL_RTL (DECL_RESULT (current_function_decl)); /* Copy the value to the return location unless it's already there. */ if (return_reg != val) { tree type = TREE_TYPE (DECL_RESULT (current_function_decl)); if (targetm.calls.promote_function_return (TREE_TYPE (current_function_decl))) { int unsignedp = TREE_UNSIGNED (type); enum machine_mode old_mode = DECL_MODE (DECL_RESULT (current_function_decl)); enum machine_mode mode = promote_mode (type, old_mode, &unsignedp, 1); if (mode != old_mode) val = convert_modes (mode, old_mode, val, unsignedp); } if (GET_CODE (return_reg) == PARALLEL) emit_group_load (return_reg, val, type, int_size_in_bytes (type)); else emit_move_insn (return_reg, val); } expand_null_return_1 (last_insn); } /* Output a return with no value. If LAST_INSN is nonzero, pretend that the return takes place after LAST_INSN. */ static void expand_null_return_1 (rtx last_insn) { rtx end_label = cleanup_label ? cleanup_label : return_label; clear_pending_stack_adjust (); do_pending_stack_adjust (); clear_last_expr (); if (end_label == 0) end_label = return_label = gen_label_rtx (); expand_goto_internal (NULL_TREE, end_label, last_insn); } /* Generate RTL to evaluate the expression RETVAL and return it from the current function. */ void expand_return (tree retval) { /* If there are any cleanups to be performed, then they will be inserted following LAST_INSN. It is desirable that the last_insn, for such purposes, should be the last insn before computing the return value. Otherwise, cleanups which call functions can clobber the return value. */ /* ??? rms: I think that is erroneous, because in C++ it would run destructors on variables that might be used in the subsequent computation of the return value. */ rtx last_insn = 0; rtx result_rtl; rtx val = 0; tree retval_rhs; /* If function wants no value, give it none. */ if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE) { expand_expr (retval, NULL_RTX, VOIDmode, 0); emit_queue (); expand_null_return (); return; } if (retval == error_mark_node) { /* Treat this like a return of no value from a function that returns a value. */ expand_null_return (); return; } else if (TREE_CODE (retval) == RESULT_DECL) retval_rhs = retval; else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR) && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL) retval_rhs = TREE_OPERAND (retval, 1); else if (VOID_TYPE_P (TREE_TYPE (retval))) /* Recognize tail-recursive call to void function. */ retval_rhs = retval; else retval_rhs = NULL_TREE; last_insn = get_last_insn (); /* Distribute return down conditional expr if either of the sides may involve tail recursion (see test below). This enhances the number of tail recursions we see. Don't do this always since it can produce sub-optimal code in some cases and we distribute assignments into conditional expressions when it would help. */ if (optimize && retval_rhs != 0 && frame_offset == 0 && TREE_CODE (retval_rhs) == COND_EXPR && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR)) { rtx label = gen_label_rtx (); tree expr; do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX); start_cleanup_deferral (); expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)), DECL_RESULT (current_function_decl), TREE_OPERAND (retval_rhs, 1)); TREE_SIDE_EFFECTS (expr) = 1; expand_return (expr); emit_label (label); expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)), DECL_RESULT (current_function_decl), TREE_OPERAND (retval_rhs, 2)); TREE_SIDE_EFFECTS (expr) = 1; expand_return (expr); end_cleanup_deferral (); return; } result_rtl = DECL_RTL (DECL_RESULT (current_function_decl)); /* If the result is an aggregate that is being returned in one (or more) registers, load the registers here. The compiler currently can't handle copying a BLKmode value into registers. We could put this code in a more general area (for use by everyone instead of just function call/return), but until this feature is generally usable it is kept here (and in expand_call). The value must go into a pseudo in case there are cleanups that will clobber the real return register. */ if (retval_rhs != 0 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode && GET_CODE (result_rtl) == REG) { int i; unsigned HOST_WIDE_INT bitpos, xbitpos; unsigned HOST_WIDE_INT padding_correction = 0; unsigned HOST_WIDE_INT bytes = int_size_in_bytes (TREE_TYPE (retval_rhs)); int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD; unsigned int bitsize = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD); rtx *result_pseudos = alloca (sizeof (rtx) * n_regs); rtx result_reg, src = NULL_RTX, dst = NULL_RTX; rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0); enum machine_mode tmpmode, result_reg_mode; if (bytes == 0) { expand_null_return (); return; } /* If the structure doesn't take up a whole number of words, see whether the register value should be padded on the left or on the right. Set PADDING_CORRECTION to the number of padding bits needed on the left side. In most ABIs, the structure will be returned at the least end of the register, which translates to right padding on little-endian targets and left padding on big-endian targets. The opposite holds if the structure is returned at the most significant end of the register. */ if (bytes % UNITS_PER_WORD != 0 && (targetm.calls.return_in_msb (TREE_TYPE (retval_rhs)) ? !BYTES_BIG_ENDIAN : BYTES_BIG_ENDIAN)) padding_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD) * BITS_PER_UNIT)); /* Copy the structure BITSIZE bits at a time. */ for (bitpos = 0, xbitpos = padding_correction; bitpos < bytes * BITS_PER_UNIT; bitpos += bitsize, xbitpos += bitsize) { /* We need a new destination pseudo each time xbitpos is on a word boundary and when xbitpos == padding_correction (the first time through). */ if (xbitpos % BITS_PER_WORD == 0 || xbitpos == padding_correction) { /* Generate an appropriate register. */ dst = gen_reg_rtx (word_mode); result_pseudos[xbitpos / BITS_PER_WORD] = dst; /* Clear the destination before we move anything into it. */ emit_move_insn (dst, CONST0_RTX (GET_MODE (dst))); } /* We need a new source operand each time bitpos is on a word boundary. */ if (bitpos % BITS_PER_WORD == 0) src = operand_subword_force (result_val, bitpos / BITS_PER_WORD, BLKmode); /* Use bitpos for the source extraction (left justified) and xbitpos for the destination store (right justified). */ store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode, extract_bit_field (src, bitsize, bitpos % BITS_PER_WORD, 1, NULL_RTX, word_mode, word_mode, BITS_PER_WORD), BITS_PER_WORD); } tmpmode = GET_MODE (result_rtl); if (tmpmode == BLKmode) { /* Find the smallest integer mode large enough to hold the entire structure and use that mode instead of BLKmode on the USE insn for the return register. */ for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmpmode != VOIDmode; tmpmode = GET_MODE_WIDER_MODE (tmpmode)) /* Have we found a large enough mode? */ if (GET_MODE_SIZE (tmpmode) >= bytes) break; /* No suitable mode found. */ if (tmpmode == VOIDmode) abort (); PUT_MODE (result_rtl, tmpmode); } if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode)) result_reg_mode = word_mode; else result_reg_mode = tmpmode; result_reg = gen_reg_rtx (result_reg_mode); emit_queue (); for (i = 0; i < n_regs; i++) emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode), result_pseudos[i]); if (tmpmode != result_reg_mode) result_reg = gen_lowpart (tmpmode, result_reg); expand_value_return (result_reg); } else if (retval_rhs != 0 && !VOID_TYPE_P (TREE_TYPE (retval_rhs)) && (GET_CODE (result_rtl) == REG || (GET_CODE (result_rtl) == PARALLEL))) { /* Calculate the return value into a temporary (usually a pseudo reg). */ tree ot = TREE_TYPE (DECL_RESULT (current_function_decl)); tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST); val = assign_temp (nt, 0, 0, 1); val = expand_expr (retval_rhs, val, GET_MODE (val), 0); val = force_not_mem (val); emit_queue (); /* Return the calculated value, doing cleanups first. */ expand_value_return (shift_return_value (val)); } else { /* No cleanups or no hard reg used; calculate value into hard return reg. */ expand_expr (retval, const0_rtx, VOIDmode, 0); emit_queue (); expand_value_return (result_rtl); } } /* Attempt to optimize a potential tail recursion call into a goto. ARGUMENTS are the arguments to a CALL_EXPR; LAST_INSN indicates where to place the jump to the tail recursion label. Return TRUE if the call was optimized into a goto. */ int optimize_tail_recursion (tree arguments, rtx last_insn) { /* Finish checking validity, and if valid emit code to set the argument variables for the new call. */ if (tail_recursion_args (arguments, DECL_ARGUMENTS (current_function_decl))) { if (tail_recursion_label == 0) { tail_recursion_label = gen_label_rtx (); emit_label_after (tail_recursion_label, tail_recursion_reentry); } emit_queue (); expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn); emit_barrier (); return 1; } return 0; } /* Emit code to alter this function's formal parms for a tail-recursive call. ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs). FORMALS is the chain of decls of formals. Return 1 if this can be done; otherwise return 0 and do not emit any code. */ static int tail_recursion_args (tree actuals, tree formals) { tree a = actuals, f = formals; int i; rtx *argvec; /* Check that number and types of actuals are compatible with the formals. This is not always true in valid C code. Also check that no formal needs to be addressable and that all formals are scalars. */ /* Also count the args. */ for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++) { if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a))) != TYPE_MAIN_VARIANT (TREE_TYPE (f))) return 0; if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode) return 0; } if (a != 0 || f != 0) return 0; /* Compute all the actuals. */ argvec = alloca (i * sizeof (rtx)); for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++) argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0); /* Find which actual values refer to current values of previous formals. Copy each of them now, before any formal is changed. */ for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++) { int copy = 0; int j; for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++) if (reg_mentioned_p (DECL_RTL (f), argvec[i])) { copy = 1; break; } if (copy) argvec[i] = copy_to_reg (argvec[i]); } /* Store the values of the actuals into the formals. */ for (f = formals, a = actuals, i = 0; f; f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++) { if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i])) emit_move_insn (DECL_RTL (f), argvec[i]); else { rtx tmp = argvec[i]; int unsignedp = TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))); promote_mode(TREE_TYPE (TREE_VALUE (a)), GET_MODE (tmp), &unsignedp, 0); if (DECL_MODE (f) != GET_MODE (DECL_RTL (f))) { tmp = gen_reg_rtx (DECL_MODE (f)); convert_move (tmp, argvec[i], unsignedp); } convert_move (DECL_RTL (f), tmp, unsignedp); } } free_temp_slots (); return 1; } /* Generate the RTL code for entering a binding contour. The variables are declared one by one, by calls to `expand_decl'. FLAGS is a bitwise or of the following flags: 1 - Nonzero if this construct should be visible to `exit_something'. 2 - Nonzero if this contour does not require a NOTE_INSN_BLOCK_BEG note. Virtually all calls from language-independent code should set this flag because they will not create corresponding BLOCK nodes. (There should be a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes and BLOCKs.) If this flag is set, MARK_ENDS should be zero when expand_end_bindings is called. If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may optionally be supplied. If so, it becomes the NOTE_BLOCK for the note. */ void expand_start_bindings_and_block (int flags, tree block) { struct nesting *thisblock = ALLOC_NESTING (); rtx note; int exit_flag = ((flags & 1) != 0); int block_flag = ((flags & 2) == 0); /* If a BLOCK is supplied, then the caller should be requesting a NOTE_INSN_BLOCK_BEG note. */ if (!block_flag && block) abort (); /* Create a note to mark the beginning of the block. */ if (block_flag) { note = emit_note (NOTE_INSN_BLOCK_BEG); NOTE_BLOCK (note) = block; } else note = emit_note (NOTE_INSN_DELETED); /* Make an entry on block_stack for the block we are entering. */ thisblock->desc = BLOCK_NESTING; thisblock->next = block_stack; thisblock->all = nesting_stack; thisblock->depth = ++nesting_depth; thisblock->data.block.stack_level = 0; thisblock->data.block.cleanups = 0; thisblock->data.block.exception_region = 0; thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level; thisblock->data.block.conditional_code = 0; thisblock->data.block.last_unconditional_cleanup = note; /* When we insert instructions after the last unconditional cleanup, we don't adjust last_insn. That means that a later add_insn will clobber the instructions we've just added. The easiest way to fix this is to just insert another instruction here, so that the instructions inserted after the last unconditional cleanup are never the last instruction. */ emit_note (NOTE_INSN_DELETED); if (block_stack && !(block_stack->data.block.cleanups == NULL_TREE && block_stack->data.block.outer_cleanups == NULL_TREE)) thisblock->data.block.outer_cleanups = tree_cons (NULL_TREE, block_stack->data.block.cleanups, block_stack->data.block.outer_cleanups); else thisblock->data.block.outer_cleanups = 0; thisblock->data.block.label_chain = 0; thisblock->data.block.innermost_stack_block = stack_block_stack; thisblock->data.block.first_insn = note; thisblock->data.block.block_start_count = ++current_block_start_count; thisblock->exit_label = exit_flag ? gen_label_rtx () : 0; block_stack = thisblock; nesting_stack = thisblock; /* Make a new level for allocating stack slots. */ push_temp_slots (); } /* Specify the scope of temporaries created by TARGET_EXPRs. Similar to CLEANUP_POINT_EXPR, but handles cases when a series of calls to expand_expr are made. After we end the region, we know that all space for all temporaries that were created by TARGET_EXPRs will be destroyed and their space freed for reuse. */ void expand_start_target_temps (void) { /* This is so that even if the result is preserved, the space allocated will be freed, as we know that it is no longer in use. */ push_temp_slots (); /* Start a new binding layer that will keep track of all cleanup actions to be performed. */ expand_start_bindings (2); target_temp_slot_level = temp_slot_level; } void expand_end_target_temps (void) { expand_end_bindings (NULL_TREE, 0, 0); /* This is so that even if the result is preserved, the space allocated will be freed, as we know that it is no longer in use. */ pop_temp_slots (); } /* Given a pointer to a BLOCK node return nonzero if (and only if) the node in question represents the outermost pair of curly braces (i.e. the "body block") of a function or method. For any BLOCK node representing a "body block" of a function or method, the BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which represents the outermost (function) scope for the function or method (i.e. the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of *that* node in turn will point to the relevant FUNCTION_DECL node. */ int is_body_block (tree stmt) { if (lang_hooks.no_body_blocks) return 0; if (TREE_CODE (stmt) == BLOCK) { tree parent = BLOCK_SUPERCONTEXT (stmt); if (parent && TREE_CODE (parent) == BLOCK) { tree grandparent = BLOCK_SUPERCONTEXT (parent); if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL) return 1; } } return 0; } /* True if we are currently emitting insns in an area of output code that is controlled by a conditional expression. This is used by the cleanup handling code to generate conditional cleanup actions. */ int conditional_context (void) { return block_stack && block_stack->data.block.conditional_code; } /* Return an opaque pointer to the current nesting level, so frontend code can check its own sanity. */ struct nesting * current_nesting_level (void) { return cfun ? block_stack : 0; } /* Emit a handler label for a nonlocal goto handler. Also emit code to store the handler label in SLOT before BEFORE_INSN. */ static rtx expand_nl_handler_label (rtx slot, rtx before_insn) { rtx insns; rtx handler_label = gen_label_rtx (); /* Don't let cleanup_cfg delete the handler. */ LABEL_PRESERVE_P (handler_label) = 1; start_sequence (); emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label)); insns = get_insns (); end_sequence (); emit_insn_before (insns, before_insn); emit_label (handler_label); return handler_label; } /* Emit code to restore vital registers at the beginning of a nonlocal goto handler. */ static void expand_nl_goto_receiver (void) { /* Clobber the FP when we get here, so we have to make sure it's marked as used by this function. */ emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx)); /* Mark the static chain as clobbered here so life information doesn't get messed up for it. */ emit_insn (gen_rtx_CLOBBER (VOIDmode, static_chain_rtx)); #ifdef HAVE_nonlocal_goto if (! HAVE_nonlocal_goto) #endif /* First adjust our frame pointer to its actual value. It was previously set to the start of the virtual area corresponding to the stacked variables when we branched here and now needs to be adjusted to the actual hardware fp value. Assignments are to virtual registers are converted by instantiate_virtual_regs into the corresponding assignment to the underlying register (fp in this case) that makes the original assignment true. So the following insn will actually be decrementing fp by STARTING_FRAME_OFFSET. */ emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx); #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM if (fixed_regs[ARG_POINTER_REGNUM]) { #ifdef ELIMINABLE_REGS /* If the argument pointer can be eliminated in favor of the frame pointer, we don't need to restore it. We assume here that if such an elimination is present, it can always be used. This is the case on all known machines; if we don't make this assumption, we do unnecessary saving on many machines. */ static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS; size_t i; for (i = 0; i < ARRAY_SIZE (elim_regs); i++) if (elim_regs[i].from == ARG_POINTER_REGNUM && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM) break; if (i == ARRAY_SIZE (elim_regs)) #endif { /* Now restore our arg pointer from the address at which it was saved in our stack frame. */ emit_move_insn (virtual_incoming_args_rtx, copy_to_reg (get_arg_pointer_save_area (cfun))); } } #endif #ifdef HAVE_nonlocal_goto_receiver if (HAVE_nonlocal_goto_receiver) emit_insn (gen_nonlocal_goto_receiver ()); #endif /* @@@ This is a kludge. Not all machine descriptions define a blockage insn, but we must not allow the code we just generated to be reordered by scheduling. Specifically, the update of the frame pointer must happen immediately, not later. So emit an ASM_INPUT to act as blockage insn. */ emit_insn (gen_rtx_ASM_INPUT (VOIDmode, "")); } /* Make handlers for nonlocal gotos taking place in the function calls in block THISBLOCK. */ static void expand_nl_goto_receivers (struct nesting *thisblock) { tree link; rtx afterward = gen_label_rtx (); rtx insns, slot; rtx label_list; int any_invalid; /* Record the handler address in the stack slot for that purpose, during this block, saving and restoring the outer value. */ if (thisblock->next != 0) for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1)) { rtx save_receiver = gen_reg_rtx (Pmode); emit_move_insn (XEXP (slot, 0), save_receiver); start_sequence (); emit_move_insn (save_receiver, XEXP (slot, 0)); insns = get_insns (); end_sequence (); emit_insn_before (insns, thisblock->data.block.first_insn); } /* Jump around the handlers; they run only when specially invoked. */ emit_jump (afterward); /* Make a separate handler for each label. */ link = nonlocal_labels; slot = nonlocal_goto_handler_slots; label_list = NULL_RTX; for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1)) /* Skip any labels we shouldn't be able to jump to from here, we generate one special handler for all of them below which just calls abort. */ if (! DECL_TOO_LATE (TREE_VALUE (link))) { rtx lab; lab = expand_nl_handler_label (XEXP (slot, 0), thisblock->data.block.first_insn); label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list); expand_nl_goto_receiver (); /* Jump to the "real" nonlocal label. */ expand_goto (TREE_VALUE (link)); } /* A second pass over all nonlocal labels; this time we handle those we should not be able to jump to at this point. */ link = nonlocal_labels; slot = nonlocal_goto_handler_slots; any_invalid = 0; for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1)) if (DECL_TOO_LATE (TREE_VALUE (link))) { rtx lab; lab = expand_nl_handler_label (XEXP (slot, 0), thisblock->data.block.first_insn); label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list); any_invalid = 1; } if (any_invalid) { expand_nl_goto_receiver (); expand_builtin_trap (); } nonlocal_goto_handler_labels = label_list; emit_label (afterward); } /* Warn about any unused VARS (which may contain nodes other than VAR_DECLs, but such nodes are ignored). The nodes are connected via the TREE_CHAIN field. */ void warn_about_unused_variables (tree vars) { tree decl; if (warn_unused_variable) for (decl = vars; decl; decl = TREE_CHAIN (decl)) if (TREE_CODE (decl) == VAR_DECL && ! TREE_USED (decl) && ! DECL_IN_SYSTEM_HEADER (decl) && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl)) warning ("%Junused variable '%D'", decl, decl); } /* Generate RTL code to terminate a binding contour. VARS is the chain of VAR_DECL nodes for the variables bound in this contour. There may actually be other nodes in this chain, but any nodes other than VAR_DECLS are ignored. MARK_ENDS is nonzero if we should put a note at the beginning and end of this binding contour. DONT_JUMP_IN is positive if it is not valid to jump into this contour, zero if we can jump into this contour only if it does not have a saved stack level, and negative if we are not to check for invalid use of labels (because the front end does that). */ void expand_end_bindings (tree vars, int mark_ends, int dont_jump_in) { struct nesting *thisblock = block_stack; /* If any of the variables in this scope were not used, warn the user. */ warn_about_unused_variables (vars); if (thisblock->exit_label) { do_pending_stack_adjust (); emit_label (thisblock->exit_label); } /* If necessary, make handlers for nonlocal gotos taking place in the function calls in this block. */ if (function_call_count != 0 && nonlocal_labels /* Make handler for outermost block if there were any nonlocal gotos to this function. */ && (thisblock->next == 0 ? current_function_has_nonlocal_label /* Make handler for inner block if it has something special to do when you jump out of it. */ : (thisblock->data.block.cleanups != 0 || thisblock->data.block.stack_level != 0))) expand_nl_goto_receivers (thisblock); /* Don't allow jumping into a block that has a stack level. Cleanups are allowed, though. */ if (dont_jump_in > 0 || (dont_jump_in == 0 && thisblock->data.block.stack_level != 0)) { struct label_chain *chain; /* Any labels in this block are no longer valid to go to. Mark them to cause an error message. */ for (chain = thisblock->data.block.label_chain; chain; chain = chain->next) { DECL_TOO_LATE (chain->label) = 1; /* If any goto without a fixup came to this label, that must be an error, because gotos without fixups come from outside all saved stack-levels. */ if (TREE_ADDRESSABLE (chain->label)) error ("%Jlabel '%D' used before containing binding contour", chain->label, chain->label); } } /* Restore stack level in effect before the block (only if variable-size objects allocated). */ /* Perform any cleanups associated with the block. */ if (thisblock->data.block.stack_level != 0 || thisblock->data.block.cleanups != 0) { int reachable; rtx insn; /* Don't let cleanups affect ({...}) constructs. */ int old_expr_stmts_for_value = expr_stmts_for_value; rtx old_last_expr_value = last_expr_value; rtx old_last_expr_alt_rtl = last_expr_alt_rtl; tree old_last_expr_type = last_expr_type; expr_stmts_for_value = 0; /* Only clean up here if this point can actually be reached. */ insn = get_last_insn (); if (GET_CODE (insn) == NOTE) insn = prev_nonnote_insn (insn); reachable = (! insn || GET_CODE (insn) != BARRIER); /* Do the cleanups. */ expand_cleanups (thisblock->data.block.cleanups, 0, reachable); if (reachable) do_pending_stack_adjust (); expr_stmts_for_value = old_expr_stmts_for_value; last_expr_value = old_last_expr_value; last_expr_alt_rtl = old_last_expr_alt_rtl; last_expr_type = old_last_expr_type; /* Restore the stack level. */ if (reachable && thisblock->data.block.stack_level != 0) { emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION, thisblock->data.block.stack_level, NULL_RTX); if (nonlocal_goto_handler_slots != 0) emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX); } /* Any gotos out of this block must also do these things. Also report any gotos with fixups that came to labels in this level. */ fixup_gotos (thisblock, thisblock->data.block.stack_level, thisblock->data.block.cleanups, thisblock->data.block.first_insn, dont_jump_in); } /* Mark the beginning and end of the scope if requested. We do this now, after running cleanups on the variables just going out of scope, so they are in scope for their cleanups. */ if (mark_ends) { rtx note = emit_note (NOTE_INSN_BLOCK_END); NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn); } else /* Get rid of the beginning-mark if we don't make an end-mark. */ NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED; /* Restore the temporary level of TARGET_EXPRs. */ target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level; /* Restore block_stack level for containing block. */ stack_block_stack = thisblock->data.block.innermost_stack_block; POPSTACK (block_stack); /* Pop the stack slot nesting and free any slots at this level. */ pop_temp_slots (); } /* Generate code to save the stack pointer at the start of the current block and set up to restore it on exit. */ void save_stack_pointer (void) { struct nesting *thisblock = block_stack; if (thisblock->data.block.stack_level == 0) { emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION, &thisblock->data.block.stack_level, thisblock->data.block.first_insn); stack_block_stack = thisblock; } } /* Generate RTL for the automatic variable declaration DECL. (Other kinds of declarations are simply ignored if seen here.) */ void expand_decl (tree decl) { tree type; type = TREE_TYPE (decl); /* For a CONST_DECL, set mode, alignment, and sizes from those of the type in case this node is used in a reference. */ if (TREE_CODE (decl) == CONST_DECL) { DECL_MODE (decl) = TYPE_MODE (type); DECL_ALIGN (decl) = TYPE_ALIGN (type); DECL_SIZE (decl) = TYPE_SIZE (type); DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type); return; } /* Otherwise, only automatic variables need any expansion done. Static and external variables, and external functions, will be handled by `assemble_variable' (called from finish_decl). TYPE_DECL requires nothing. PARM_DECLs are handled in `assign_parms'. */ if (TREE_CODE (decl) != VAR_DECL) return; if (TREE_STATIC (decl) || DECL_EXTERNAL (decl)) return; /* Create the RTL representation for the variable. */ if (type == error_mark_node) SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx)); else if (DECL_SIZE (decl) == 0) /* Variable with incomplete type. */ { rtx x; if (DECL_INITIAL (decl) == 0) /* Error message was already done; now avoid a crash. */ x = gen_rtx_MEM (BLKmode, const0_rtx); else /* An initializer is going to decide the size of this array. Until we know the size, represent its address with a reg. */ x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode)); set_mem_attributes (x, decl, 1); SET_DECL_RTL (decl, x); } else if (DECL_MODE (decl) != BLKmode /* If -ffloat-store, don't put explicit float vars into regs. */ && !(flag_float_store && TREE_CODE (type) == REAL_TYPE) && ! TREE_THIS_VOLATILE (decl) && ! DECL_NONLOCAL (decl) && (DECL_REGISTER (decl) || DECL_ARTIFICIAL (decl) || optimize)) { /* Automatic variable that can go in a register. */ int unsignedp = TREE_UNSIGNED (type); enum machine_mode reg_mode = promote_mode (type, DECL_MODE (decl), &unsignedp, 0); SET_DECL_RTL (decl, gen_reg_rtx (reg_mode)); if (!DECL_ARTIFICIAL (decl)) mark_user_reg (DECL_RTL (decl)); if (POINTER_TYPE_P (type)) mark_reg_pointer (DECL_RTL (decl), TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl)))); maybe_set_unchanging (DECL_RTL (decl), decl); /* If something wants our address, try to use ADDRESSOF. */ if (TREE_ADDRESSABLE (decl)) put_var_into_stack (decl, /*rescan=*/false); } else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST && ! (flag_stack_check && ! STACK_CHECK_BUILTIN && 0 < compare_tree_int (DECL_SIZE_UNIT (decl), STACK_CHECK_MAX_VAR_SIZE))) { /* Variable of fixed size that goes on the stack. */ rtx oldaddr = 0; rtx addr; rtx x; /* If we previously made RTL for this decl, it must be an array whose size was determined by the initializer. The old address was a register; set that register now to the proper address. */ if (DECL_RTL_SET_P (decl)) { if (GET_CODE (DECL_RTL (decl)) != MEM || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG) abort (); oldaddr = XEXP (DECL_RTL (decl), 0); } /* Set alignment we actually gave this decl. */ DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT : GET_MODE_BITSIZE (DECL_MODE (decl))); DECL_USER_ALIGN (decl) = 0; x = assign_temp (decl, 1, 1, 1); set_mem_attributes (x, decl, 1); SET_DECL_RTL (decl, x); if (oldaddr) { addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr); if (addr != oldaddr) emit_move_insn (oldaddr, addr); } } else /* Dynamic-size object: must push space on the stack. */ { rtx address, size, x; /* Record the stack pointer on entry to block, if have not already done so. */ do_pending_stack_adjust (); save_stack_pointer (); /* In function-at-a-time mode, variable_size doesn't expand this, so do it now. */ if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type)) expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)), const0_rtx, VOIDmode, 0); /* Compute the variable's size, in bytes. */ size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0); free_temp_slots (); /* Allocate space on the stack for the variable. Note that DECL_ALIGN says how the variable is to be aligned and we cannot use it to conclude anything about the alignment of the size. */ address = allocate_dynamic_stack_space (size, NULL_RTX, TYPE_ALIGN (TREE_TYPE (decl))); /* Reference the variable indirect through that rtx. */ x = gen_rtx_MEM (DECL_MODE (decl), address); set_mem_attributes (x, decl, 1); SET_DECL_RTL (decl, x); /* Indicate the alignment we actually gave this variable. */ #ifdef STACK_BOUNDARY DECL_ALIGN (decl) = STACK_BOUNDARY; #else DECL_ALIGN (decl) = BIGGEST_ALIGNMENT; #endif DECL_USER_ALIGN (decl) = 0; } } /* Emit code to perform the initialization of a declaration DECL. */ void expand_decl_init (tree decl) { int was_used = TREE_USED (decl); /* If this is a CONST_DECL, we don't have to generate any code. Likewise for static decls. */ if (TREE_CODE (decl) == CONST_DECL || TREE_STATIC (decl)) return; /* Compute and store the initial value now. */ push_temp_slots (); if (DECL_INITIAL (decl) == error_mark_node) { enum tree_code code = TREE_CODE (TREE_TYPE (decl)); if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE || code == POINTER_TYPE || code == REFERENCE_TYPE) expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node), 0); emit_queue (); } else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST) { emit_line_note (DECL_SOURCE_LOCATION (decl)); expand_assignment (decl, DECL_INITIAL (decl), 0); emit_queue (); } /* Don't let the initialization count as "using" the variable. */ TREE_USED (decl) = was_used; /* Free any temporaries we made while initializing the decl. */ preserve_temp_slots (NULL_RTX); free_temp_slots (); pop_temp_slots (); } /* CLEANUP is an expression to be executed at exit from this binding contour; for example, in C++, it might call the destructor for this variable. We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the CLEANUP multiple times, and have the correct semantics. This happens in exception handling, for gotos, returns, breaks that leave the current scope. If CLEANUP is nonzero and DECL is zero, we record a cleanup that is not associated with any particular variable. */ int expand_decl_cleanup (tree decl, tree cleanup) { struct nesting *thisblock; /* Error if we are not in any block. */ if (cfun == 0 || block_stack == 0) return 0; thisblock = block_stack; /* Record the cleanup if there is one. */ if (cleanup != 0) { tree t; rtx seq; tree *cleanups = &thisblock->data.block.cleanups; int cond_context = conditional_context (); if (cond_context) { rtx flag = gen_reg_rtx (word_mode); rtx set_flag_0; tree cond; start_sequence (); emit_move_insn (flag, const0_rtx); set_flag_0 = get_insns (); end_sequence (); thisblock->data.block.last_unconditional_cleanup = emit_insn_after (set_flag_0, thisblock->data.block.last_unconditional_cleanup); emit_move_insn (flag, const1_rtx); cond = build_decl (VAR_DECL, NULL_TREE, (*lang_hooks.types.type_for_mode) (word_mode, 1)); SET_DECL_RTL (cond, flag); /* Conditionalize the cleanup. */ cleanup = build (COND_EXPR, void_type_node, (*lang_hooks.truthvalue_conversion) (cond), cleanup, integer_zero_node); cleanup = fold (cleanup); cleanups = &thisblock->data.block.cleanups; } cleanup = unsave_expr (cleanup); t = *cleanups = tree_cons (decl, cleanup, *cleanups); if (! cond_context) /* If this block has a cleanup, it belongs in stack_block_stack. */ stack_block_stack = thisblock; if (cond_context) { start_sequence (); } if (! using_eh_for_cleanups_p) TREE_ADDRESSABLE (t) = 1; else expand_eh_region_start (); if (cond_context) { seq = get_insns (); end_sequence (); if (seq) thisblock->data.block.last_unconditional_cleanup = emit_insn_after (seq, thisblock->data.block.last_unconditional_cleanup); } else { thisblock->data.block.last_unconditional_cleanup = get_last_insn (); /* When we insert instructions after the last unconditional cleanup, we don't adjust last_insn. That means that a later add_insn will clobber the instructions we've just added. The easiest way to fix this is to just insert another instruction here, so that the instructions inserted after the last unconditional cleanup are never the last instruction. */ emit_note (NOTE_INSN_DELETED); } } return 1; } /* Like expand_decl_cleanup, but maybe only run the cleanup if an exception is thrown. */ int expand_decl_cleanup_eh (tree decl, tree cleanup, int eh_only) { int ret = expand_decl_cleanup (decl, cleanup); if (cleanup && ret) { tree node = block_stack->data.block.cleanups; CLEANUP_EH_ONLY (node) = eh_only; } return ret; } /* DECL is an anonymous union. CLEANUP is a cleanup for DECL. DECL_ELTS is the list of elements that belong to DECL's type. In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */ void expand_anon_union_decl (tree decl, tree cleanup, tree decl_elts) { struct nesting *thisblock = cfun == 0 ? 0 : block_stack; rtx x; tree t; /* If any of the elements are addressable, so is the entire union. */ for (t = decl_elts; t; t = TREE_CHAIN (t)) if (TREE_ADDRESSABLE (TREE_VALUE (t))) { TREE_ADDRESSABLE (decl) = 1; break; } expand_decl (decl); expand_decl_cleanup (decl, cleanup); x = DECL_RTL (decl); /* Go through the elements, assigning RTL to each. */ for (t = decl_elts; t; t = TREE_CHAIN (t)) { tree decl_elt = TREE_VALUE (t); tree cleanup_elt = TREE_PURPOSE (t); enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt)); /* If any of the elements are addressable, so is the entire union. */ if (TREE_USED (decl_elt)) TREE_USED (decl) = 1; /* Propagate the union's alignment to the elements. */ DECL_ALIGN (decl_elt) = DECL_ALIGN (decl); DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl); /* If the element has BLKmode and the union doesn't, the union is aligned such that the element doesn't need to have BLKmode, so change the element's mode to the appropriate one for its size. */ if (mode == BLKmode && DECL_MODE (decl) != BLKmode) DECL_MODE (decl_elt) = mode = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1); /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we instead create a new MEM rtx with the proper mode. */ if (GET_CODE (x) == MEM) { if (mode == GET_MODE (x)) SET_DECL_RTL (decl_elt, x); else SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0)); } else if (GET_CODE (x) == REG) { if (mode == GET_MODE (x)) SET_DECL_RTL (decl_elt, x); else SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x)); } else abort (); /* Record the cleanup if there is one. */ if (cleanup != 0) thisblock->data.block.cleanups = tree_cons (decl_elt, cleanup_elt, thisblock->data.block.cleanups); } } /* Expand a list of cleanups LIST. Elements may be expressions or may be nested lists. If IN_FIXUP is nonzero, we are generating this cleanup for a fixup goto and handle protection regions specially in that case. If REACHABLE, we emit code, otherwise just inform the exception handling code about this finalization. */ static void expand_cleanups (tree list, int in_fixup, int reachable) { tree tail; for (tail = list; tail; tail = TREE_CHAIN (tail)) if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST) expand_cleanups (TREE_VALUE (tail), in_fixup, reachable); else { if (! in_fixup && using_eh_for_cleanups_p) expand_eh_region_end_cleanup (TREE_VALUE (tail)); if (reachable && !CLEANUP_EH_ONLY (tail)) { /* Cleanups may be run multiple times. For example, when exiting a binding contour, we expand the cleanups associated with that contour. When a goto within that binding contour has a target outside that contour, it will expand all cleanups from its scope to the target. Though the cleanups are expanded multiple times, the control paths are non-overlapping so the cleanups will not be executed twice. */ /* We may need to protect from outer cleanups. */ if (in_fixup && using_eh_for_cleanups_p) { expand_eh_region_start (); expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0); expand_eh_region_end_fixup (TREE_VALUE (tail)); } else expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0); free_temp_slots (); } } } /* Mark when the context we are emitting RTL for as a conditional context, so that any cleanup actions we register with expand_decl_init will be properly conditionalized when those cleanup actions are later performed. Must be called before any expression (tree) is expanded that is within a conditional context. */ void start_cleanup_deferral (void) { /* block_stack can be NULL if we are inside the parameter list. It is OK to do nothing, because cleanups aren't possible here. */ if (block_stack) ++block_stack->data.block.conditional_code; } /* Mark the end of a conditional region of code. Because cleanup deferrals may be nested, we may still be in a conditional region after we end the currently deferred cleanups, only after we end all deferred cleanups, are we back in unconditional code. */ void end_cleanup_deferral (void) { /* block_stack can be NULL if we are inside the parameter list. It is OK to do nothing, because cleanups aren't possible here. */ if (block_stack) --block_stack->data.block.conditional_code; } tree last_cleanup_this_contour (void) { if (block_stack == 0) return 0; return block_stack->data.block.cleanups; } /* Return 1 if there are any pending cleanups at this point. Check the current contour as well as contours that enclose the current contour. */ int any_pending_cleanups (void) { struct nesting *block; if (cfun == NULL || cfun->stmt == NULL || block_stack == 0) return 0; if (block_stack->data.block.cleanups != NULL) return 1; if (block_stack->data.block.outer_cleanups == 0) return 0; for (block = block_stack->next; block; block = block->next) if (block->data.block.cleanups != 0) return 1; return 0; } /* Enter a case (Pascal) or switch (C) statement. Push a block onto case_stack and nesting_stack to accumulate the case-labels that are seen and to record the labels generated for the statement. EXIT_FLAG is nonzero if `exit_something' should exit this case stmt. Otherwise, this construct is transparent for `exit_something'. EXPR is the index-expression to be dispatched on. TYPE is its nominal type. We could simply convert EXPR to this type, but instead we take short cuts. */ void expand_start_case (int exit_flag, tree expr, tree type, const char *printname) { struct nesting *thiscase = ALLOC_NESTING (); /* Make an entry on case_stack for the case we are entering. */ thiscase->desc = CASE_NESTING; thiscase->next = case_stack; thiscase->all = nesting_stack; thiscase->depth = ++nesting_depth; thiscase->exit_label = exit_flag ? gen_label_rtx () : 0; thiscase->data.case_stmt.case_list = 0; thiscase->data.case_stmt.index_expr = expr; thiscase->data.case_stmt.nominal_type = type; thiscase->data.case_stmt.default_label = 0; thiscase->data.case_stmt.printname = printname; thiscase->data.case_stmt.line_number_status = force_line_numbers (); case_stack = thiscase; nesting_stack = thiscase; do_pending_stack_adjust (); emit_queue (); /* Make sure case_stmt.start points to something that won't need any transformation before expand_end_case. */ if (GET_CODE (get_last_insn ()) != NOTE) emit_note (NOTE_INSN_DELETED); thiscase->data.case_stmt.start = get_last_insn (); start_cleanup_deferral (); } /* Start a "dummy case statement" within which case labels are invalid and are not connected to any larger real case statement. This can be used if you don't want to let a case statement jump into the middle of certain kinds of constructs. */ void expand_start_case_dummy (void) { struct nesting *thiscase = ALLOC_NESTING (); /* Make an entry on case_stack for the dummy. */ thiscase->desc = CASE_NESTING; thiscase->next = case_stack; thiscase->all = nesting_stack; thiscase->depth = ++nesting_depth; thiscase->exit_label = 0; thiscase->data.case_stmt.case_list = 0; thiscase->data.case_stmt.start = 0; thiscase->data.case_stmt.nominal_type = 0; thiscase->data.case_stmt.default_label = 0; case_stack = thiscase; nesting_stack = thiscase; start_cleanup_deferral (); } static void check_seenlabel (void) { /* If this is the first label, warn if any insns have been emitted. */ if (case_stack->data.case_stmt.line_number_status >= 0) { rtx insn; restore_line_number_status (case_stack->data.case_stmt.line_number_status); case_stack->data.case_stmt.line_number_status = -1; for (insn = case_stack->data.case_stmt.start; insn; insn = NEXT_INSN (insn)) { if (GET_CODE (insn) == CODE_LABEL) break; if (GET_CODE (insn) != NOTE && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE)) { do insn = PREV_INSN (insn); while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0)); /* If insn is zero, then there must have been a syntax error. */ if (insn) { location_t locus; locus.file = NOTE_SOURCE_FILE (insn); locus.line = NOTE_LINE_NUMBER (insn); warning ("%Hunreachable code at beginning of %s", &locus, case_stack->data.case_stmt.printname); } break; } } } } /* Accumulate one case or default label inside a case or switch statement. VALUE is the value of the case (a null pointer, for a default label). The function CONVERTER, when applied to arguments T and V, converts the value V to the type T. If not currently inside a case or switch statement, return 1 and do nothing. The caller will print a language-specific error message. If VALUE is a duplicate or overlaps, return 2 and do nothing except store the (first) duplicate node in *DUPLICATE. If VALUE is out of range, return 3 and do nothing. If we are jumping into the scope of a cleanup or var-sized array, return 5. Return 0 on success. Extended to handle range statements. */ int pushcase (tree value, tree (*converter) (tree, tree), tree label, tree *duplicate) { tree index_type; tree nominal_type; /* Fail if not inside a real case statement. */ if (! (case_stack && case_stack->data.case_stmt.start)) return 1; if (stack_block_stack && stack_block_stack->depth > case_stack->depth) return 5; index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr); nominal_type = case_stack->data.case_stmt.nominal_type; /* If the index is erroneous, avoid more problems: pretend to succeed. */ if (index_type == error_mark_node) return 0; /* Convert VALUE to the type in which the comparisons are nominally done. */ if (value != 0) value = (*converter) (nominal_type, value); check_seenlabel (); /* Fail if this value is out of range for the actual type of the index (which may be narrower than NOMINAL_TYPE). */ if (value != 0 && (TREE_CONSTANT_OVERFLOW (value) || ! int_fits_type_p (value, index_type))) return 3; return add_case_node (value, value, label, duplicate); } /* Like pushcase but this case applies to all values between VALUE1 and VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest value of the index type and ends at VALUE2. If VALUE2 is NULL, the range starts at VALUE1 and ends at the highest value of the index type. If both are NULL, this case applies to all values. The return value is the same as that of pushcase but there is one additional error code: 4 means the specified range was empty. */ int pushcase_range (tree value1, tree value2, tree (*converter) (tree, tree), tree label, tree *duplicate) { tree index_type; tree nominal_type; /* Fail if not inside a real case statement. */ if (! (case_stack && case_stack->data.case_stmt.start)) return 1; if (stack_block_stack && stack_block_stack->depth > case_stack->depth) return 5; index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr); nominal_type = case_stack->data.case_stmt.nominal_type; /* If the index is erroneous, avoid more problems: pretend to succeed. */ if (index_type == error_mark_node) return 0; check_seenlabel (); /* Convert VALUEs to type in which the comparisons are nominally done and replace any unspecified value with the corresponding bound. */ if (value1 == 0) value1 = TYPE_MIN_VALUE (index_type); if (value2 == 0) value2 = TYPE_MAX_VALUE (index_type); /* Fail if the range is empty. Do this before any conversion since we want to allow out-of-range empty ranges. */ if (value2 != 0 && tree_int_cst_lt (value2, value1)) return 4; /* If the max was unbounded, use the max of the nominal_type we are converting to. Do this after the < check above to suppress false positives. */ if (value2 == 0) value2 = TYPE_MAX_VALUE (nominal_type); value1 = (*converter) (nominal_type, value1); value2 = (*converter) (nominal_type, value2); /* Fail if these values are out of range. */ if (TREE_CONSTANT_OVERFLOW (value1) || ! int_fits_type_p (value1, index_type)) return 3; if (TREE_CONSTANT_OVERFLOW (value2) || ! int_fits_type_p (value2, index_type)) return 3; return add_case_node (value1, value2, label, duplicate); } /* Do the actual insertion of a case label for pushcase and pushcase_range into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid slowdown for large switch statements. */ int add_case_node (tree low, tree high, tree label, tree *duplicate) { struct case_node *p, **q, *r; /* If there's no HIGH value, then this is not a case range; it's just a simple case label. But that's just a degenerate case range. */ if (!high) high = low; /* Handle default labels specially. */ if (!high && !low) { if (case_stack->data.case_stmt.default_label != 0) { *duplicate = case_stack->data.case_stmt.default_label; return 2; } case_stack->data.case_stmt.default_label = label; expand_label (label); return 0; } q = &case_stack->data.case_stmt.case_list; p = *q; while ((r = *q)) { p = r; /* Keep going past elements distinctly greater than HIGH. */ if (tree_int_cst_lt (high, p->low)) q = &p->left; /* or distinctly less than LOW. */ else if (tree_int_cst_lt (p->high, low)) q = &p->right; else { /* We have an overlap; this is an error. */ *duplicate = p->code_label; return 2; } } /* Add this label to the chain, and succeed. */ r = ggc_alloc (sizeof (struct case_node)); r->low = low; /* If the bounds are equal, turn this into the one-value case. */ if (tree_int_cst_equal (low, high)) r->high = r->low; else r->high = high; r->code_label = label; expand_label (label); *q = r; r->parent = p; r->left = 0; r->right = 0; r->balance = 0; while (p) { struct case_node *s; if (r == p->left) { int b; if (! (b = p->balance)) /* Growth propagation from left side. */ p->balance = -1; else if (b < 0) { if (r->balance < 0) { /* R-Rotation */ if ((p->left = s = r->right)) s->parent = p; r->right = p; p->balance = 0; r->balance = 0; s = p->parent; p->parent = r; if ((r->parent = s)) { if (s->left == p) s->left = r; else s->right = r; } else case_stack->data.case_stmt.case_list = r; } else /* r->balance == +1 */ { /* LR-Rotation */ int b2; struct case_node *t = r->right; if ((p->left = s = t->right)) s->parent = p; t->right = p; if ((r->right = s = t->left)) s->parent = r; t->left = r; b = t->balance; b2 = b < 0; p->balance = b2; b2 = -b2 - b; r->balance = b2; t->balance = 0; s = p->parent; p->parent = t; r->parent = t; if ((t->parent = s)) { if (s->left == p) s->left = t; else s->right = t; } else case_stack->data.case_stmt.case_list = t; } break; } else { /* p->balance == +1; growth of left side balances the node. */ p->balance = 0; break; } } else /* r == p->right */ { int b; if (! (b = p->balance)) /* Growth propagation from right side. */ p->balance++; else if (b > 0) { if (r->balance > 0) { /* L-Rotation */ if ((p->right = s = r->left)) s->parent = p; r->left = p; p->balance = 0; r->balance = 0; s = p->parent; p->parent = r; if ((r->parent = s)) { if (s->left == p) s->left = r; else s->right = r; } else case_stack->data.case_stmt.case_list = r; } else /* r->balance == -1 */ { /* RL-Rotation */ int b2; struct case_node *t = r->left; if ((p->right = s = t->left)) s->parent = p; t->left = p; if ((r->left = s = t->right)) s->parent = r; t->right = r; b = t->balance; b2 = b < 0; r->balance = b2; b2 = -b2 - b; p->balance = b2; t->balance = 0; s = p->parent; p->parent = t; r->parent = t; if ((t->parent = s)) { if (s->left == p) s->left = t; else s->right = t; } else case_stack->data.case_stmt.case_list = t; } break; } else { /* p->balance == -1; growth of right side balances the node. */ p->balance = 0; break; } } r = p; p = p->parent; } return 0; } /* Returns the number of possible values of TYPE. Returns -1 if the number is unknown, variable, or if the number does not fit in a HOST_WIDE_INT. Sets *SPARSENESS to 2 if TYPE is an ENUMERAL_TYPE whose values do not increase monotonically (there may be duplicates); to 1 if the values increase monotonically, but not always by 1; otherwise sets it to 0. */ HOST_WIDE_INT all_cases_count (tree type, int *sparseness) { tree t; HOST_WIDE_INT count, minval, lastval; *sparseness = 0; switch (TREE_CODE (type)) { case BOOLEAN_TYPE: count = 2; break; case CHAR_TYPE: count = 1 << BITS_PER_UNIT; break; default: case INTEGER_TYPE: if (TYPE_MAX_VALUE (type) != 0 && 0 != (t = fold (build (MINUS_EXPR, type, TYPE_MAX_VALUE (type), TYPE_MIN_VALUE (type)))) && 0 != (t = fold (build (PLUS_EXPR, type, t, convert (type, integer_zero_node)))) && host_integerp (t, 1)) count = tree_low_cst (t, 1); else return -1; break; case ENUMERAL_TYPE: /* Don't waste time with enumeral types with huge values. */ if (! host_integerp (TYPE_MIN_VALUE (type), 0) || TYPE_MAX_VALUE (type) == 0 || ! host_integerp (TYPE_MAX_VALUE (type), 0)) return -1; lastval = minval = tree_low_cst (TYPE_MIN_VALUE (type), 0); count = 0; for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t)) { HOST_WIDE_INT thisval = tree_low_cst (TREE_VALUE (t), 0); if (*sparseness == 2 || thisval <= lastval) *sparseness = 2; else if (thisval != minval + count) *sparseness = 1; lastval = thisval; count++; } } return count; } #define BITARRAY_TEST(ARRAY, INDEX) \ ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\ & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))) #define BITARRAY_SET(ARRAY, INDEX) \ ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\ |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)) /* Set the elements of the bitstring CASES_SEEN (which has length COUNT), with the case values we have seen, assuming the case expression has the given TYPE. SPARSENESS is as determined by all_cases_count. The time needed is proportional to COUNT, unless SPARSENESS is 2, in which case quadratic time is needed. */ void mark_seen_cases (tree type, unsigned char *cases_seen, HOST_WIDE_INT count, int sparseness) { tree next_node_to_try = NULL_TREE; HOST_WIDE_INT next_node_offset = 0; struct case_node *n, *root = case_stack->data.case_stmt.case_list; tree val = make_node (INTEGER_CST); TREE_TYPE (val) = type; if (! root) /* Do nothing. */ ; else if (sparseness == 2) { tree t; unsigned HOST_WIDE_INT xlo; /* This less efficient loop is only needed to handle duplicate case values (multiple enum constants with the same value). */ TREE_TYPE (val) = TREE_TYPE (root->low); for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE; t = TREE_CHAIN (t), xlo++) { TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t)); TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t)); n = root; do { /* Keep going past elements distinctly greater than VAL. */ if (tree_int_cst_lt (val, n->low)) n = n->left; /* or distinctly less than VAL. */ else if (tree_int_cst_lt (n->high, val)) n = n->right; else { /* We have found a matching range. */ BITARRAY_SET (cases_seen, xlo); break; } } while (n); } } else { if (root->left) case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0); for (n = root; n; n = n->right) { TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low); TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low); while (! tree_int_cst_lt (n->high, val)) { /* Calculate (into xlo) the "offset" of the integer (val). The element with lowest value has offset 0, the next smallest element has offset 1, etc. */ unsigned HOST_WIDE_INT xlo; HOST_WIDE_INT xhi; tree t; if (sparseness && TYPE_VALUES (type) != NULL_TREE) { /* The TYPE_VALUES will be in increasing order, so starting searching where we last ended. */ t = next_node_to_try; xlo = next_node_offset; xhi = 0; for (;;) { if (t == NULL_TREE) { t = TYPE_VALUES (type); xlo = 0; } if (tree_int_cst_equal (val, TREE_VALUE (t))) { next_node_to_try = TREE_CHAIN (t); next_node_offset = xlo + 1; break; } xlo++; t = TREE_CHAIN (t); if (t == next_node_to_try) { xlo = -1; break; } } } else { t = TYPE_MIN_VALUE (type); if (t) neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t), &xlo, &xhi); else xlo = xhi = 0; add_double (xlo, xhi, TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val), &xlo, &xhi); } if (xhi == 0 && xlo < (unsigned HOST_WIDE_INT) count) BITARRAY_SET (cases_seen, xlo); add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val), 1, 0, &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val)); } } } } /* Given a switch statement with an expression that is an enumeration type, warn if any of the enumeration type's literals are not covered by the case expressions of the switch. Also, warn if there are any extra switch cases that are *not* elements of the enumerated type. Historical note: At one stage this function would: ``If all enumeration literals were covered by the case expressions, turn one of the expressions into the default expression since it should not be possible to fall through such a switch.'' That code has since been removed as: ``This optimization is disabled because it causes valid programs to fail. ANSI C does not guarantee that an expression with enum type will have a value that is the same as one of the enumeration literals.'' */ void check_for_full_enumeration_handling (tree type) { struct case_node *n; tree chain; /* True iff the selector type is a numbered set mode. */ int sparseness = 0; /* The number of possible selector values. */ HOST_WIDE_INT size; /* For each possible selector value. a one iff it has been matched by a case value alternative. */ unsigned char *cases_seen; /* The allocated size of cases_seen, in chars. */ HOST_WIDE_INT bytes_needed; size = all_cases_count (type, &sparseness); bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR; if (size > 0 && size < 600000 /* We deliberately use calloc here, not cmalloc, so that we can suppress this optimization if we don't have enough memory rather than aborting, as xmalloc would do. */ && (cases_seen = really_call_calloc (bytes_needed, 1)) != NULL) { HOST_WIDE_INT i; tree v = TYPE_VALUES (type); /* The time complexity of this code is normally O(N), where N being the number of members in the enumerated type. However, if type is an ENUMERAL_TYPE whose values do not increase monotonically, O(N*log(N)) time may be needed. */ mark_seen_cases (type, cases_seen, size, sparseness); for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v)) if (BITARRAY_TEST (cases_seen, i) == 0) warning ("enumeration value `%s' not handled in switch", IDENTIFIER_POINTER (TREE_PURPOSE (v))); free (cases_seen); } /* Now we go the other way around; we warn if there are case expressions that don't correspond to enumerators. This can occur since C and C++ don't enforce type-checking of assignments to enumeration variables. */ if (case_stack->data.case_stmt.case_list && case_stack->data.case_stmt.case_list->left) case_stack->data.case_stmt.case_list = case_tree2list (case_stack->data.case_stmt.case_list, 0); for (n = case_stack->data.case_stmt.case_list; n; n = n->right) { for (chain = TYPE_VALUES (type); chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain)); chain = TREE_CHAIN (chain)) ; if (!chain) { if (TYPE_NAME (type) == 0) warning ("case value `%ld' not in enumerated type", (long) TREE_INT_CST_LOW (n->low)); else warning ("case value `%ld' not in enumerated type `%s'", (long) TREE_INT_CST_LOW (n->low), IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE) ? TYPE_NAME (type) : DECL_NAME (TYPE_NAME (type)))); } if (!tree_int_cst_equal (n->low, n->high)) { for (chain = TYPE_VALUES (type); chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain)); chain = TREE_CHAIN (chain)) ; if (!chain) { if (TYPE_NAME (type) == 0) warning ("case value `%ld' not in enumerated type", (long) TREE_INT_CST_LOW (n->high)); else warning ("case value `%ld' not in enumerated type `%s'", (long) TREE_INT_CST_LOW (n->high), IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE) ? TYPE_NAME (type) : DECL_NAME (TYPE_NAME (type)))); } } } } /* Maximum number of case bit tests. */ #define MAX_CASE_BIT_TESTS 3 /* By default, enable case bit tests on targets with ashlsi3. */ #ifndef CASE_USE_BIT_TESTS #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \ != CODE_FOR_nothing) #endif /* A case_bit_test represents a set of case nodes that may be selected from using a bit-wise comparison. HI and LO hold the integer to be tested against, LABEL contains the label to jump to upon success and BITS counts the number of case nodes handled by this test, typically the number of bits set in HI:LO. */ struct case_bit_test { HOST_WIDE_INT hi; HOST_WIDE_INT lo; rtx label; int bits; }; /* Determine whether "1 << x" is relatively cheap in word_mode. */ static bool lshift_cheap_p (void) { static bool init = false; static bool cheap = true; if (!init) { rtx reg = gen_rtx_REG (word_mode, 10000); int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET); cheap = cost < COSTS_N_INSNS (3); init = true; } return cheap; } /* Comparison function for qsort to order bit tests by decreasing number of case nodes, i.e. the node with the most cases gets tested first. */ static int case_bit_test_cmp (const void *p1, const void *p2) { const struct case_bit_test *d1 = p1; const struct case_bit_test *d2 = p2; return d2->bits - d1->bits; } /* Expand a switch statement by a short sequence of bit-wise comparisons. "switch(x)" is effectively converted into "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are integer constants. INDEX_EXPR is the value being switched on, which is of type INDEX_TYPE. MINVAL is the lowest case value of in the case nodes, of INDEX_TYPE type, and RANGE is highest value minus MINVAL, also of type INDEX_TYPE. NODES is the set of case nodes, and DEFAULT_LABEL is the label to branch to should none of the cases match. There *MUST* be MAX_CASE_BIT_TESTS or less unique case node targets. */ static void emit_case_bit_tests (tree index_type, tree index_expr, tree minval, tree range, case_node_ptr nodes, rtx default_label) { struct case_bit_test test[MAX_CASE_BIT_TESTS]; enum machine_mode mode; rtx expr, index, label; unsigned int i,j,lo,hi; struct case_node *n; unsigned int count; count = 0; for (n = nodes; n; n = n->right) { label = label_rtx (n->code_label); for (i = 0; i < count; i++) if (same_case_target_p (label, test[i].label)) break; if (i == count) { if (count >= MAX_CASE_BIT_TESTS) abort (); test[i].hi = 0; test[i].lo = 0; test[i].label = label; test[i].bits = 1; count++; } else test[i].bits++; lo = tree_low_cst (fold (build (MINUS_EXPR, index_type, n->low, minval)), 1); hi = tree_low_cst (fold (build (MINUS_EXPR, index_type, n->high, minval)), 1); for (j = lo; j <= hi; j++) if (j >= HOST_BITS_PER_WIDE_INT) test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT); else test[i].lo |= (HOST_WIDE_INT) 1 << j; } qsort (test, count, sizeof(*test), case_bit_test_cmp); index_expr = fold (build (MINUS_EXPR, index_type, convert (index_type, index_expr), convert (index_type, minval))); index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0); emit_queue (); index = protect_from_queue (index, 0); do_pending_stack_adjust (); mode = TYPE_MODE (index_type); expr = expand_expr (range, NULL_RTX, VOIDmode, 0); emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1, default_label); index = convert_to_mode (word_mode, index, 0); index = expand_binop (word_mode, ashl_optab, const1_rtx, index, NULL_RTX, 1, OPTAB_WIDEN); for (i = 0; i < count; i++) { expr = immed_double_const (test[i].lo, test[i].hi, word_mode); expr = expand_binop (word_mode, and_optab, index, expr, NULL_RTX, 1, OPTAB_WIDEN); emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX, word_mode, 1, test[i].label); } emit_jump (default_label); } /* Terminate a case (Pascal) or switch (C) statement in which ORIG_INDEX is the expression to be tested. If ORIG_TYPE is not NULL, it is the original ORIG_INDEX type as given in the source before any compiler conversions. Generate the code to test it and jump to the right place. */ void expand_end_case_type (tree orig_index, tree orig_type) { tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE; rtx default_label = 0; struct case_node *n, *m; unsigned int count, uniq; rtx index; rtx table_label; int ncases; rtx *labelvec; int i; rtx before_case, end, lab; struct nesting *thiscase = case_stack; tree index_expr, index_type; bool exit_done = false; int unsignedp; /* Don't crash due to previous errors. */ if (thiscase == NULL) return; index_expr = thiscase->data.case_stmt.index_expr; index_type = TREE_TYPE (index_expr); unsignedp = TREE_UNSIGNED (index_type); if (orig_type == NULL) orig_type = TREE_TYPE (orig_index); do_pending_stack_adjust (); /* This might get a spurious warning in the presence of a syntax error; it could be fixed by moving the call to check_seenlabel after the check for error_mark_node, and copying the code of check_seenlabel that deals with case_stack->data.case_stmt.line_number_status / restore_line_number_status in front of the call to end_cleanup_deferral; However, this might miss some useful warnings in the presence of non-syntax errors. */ check_seenlabel (); /* An ERROR_MARK occurs for various reasons including invalid data type. */ if (index_type != error_mark_node) { /* If the switch expression was an enumerated type, check that exactly all enumeration literals are covered by the cases. The check is made when -Wswitch was specified and there is no default case, or when -Wswitch-enum was specified. */ if (((warn_switch && !thiscase->data.case_stmt.default_label) || warn_switch_enum) && TREE_CODE (orig_type) == ENUMERAL_TYPE && TREE_CODE (index_expr) != INTEGER_CST) check_for_full_enumeration_handling (orig_type); if (warn_switch_default && !thiscase->data.case_stmt.default_label) warning ("switch missing default case"); /* If we don't have a default-label, create one here, after the body of the switch. */ if (thiscase->data.case_stmt.default_label == 0) { thiscase->data.case_stmt.default_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE); /* Share the exit label if possible. */ if (thiscase->exit_label) { SET_DECL_RTL (thiscase->data.case_stmt.default_label, thiscase->exit_label); exit_done = true; } expand_label (thiscase->data.case_stmt.default_label); } default_label = label_rtx (thiscase->data.case_stmt.default_label); before_case = get_last_insn (); if (thiscase->data.case_stmt.case_list && thiscase->data.case_stmt.case_list->left) thiscase->data.case_stmt.case_list = case_tree2list (thiscase->data.case_stmt.case_list, 0); /* Simplify the case-list before we count it. */ group_case_nodes (thiscase->data.case_stmt.case_list); strip_default_case_nodes (&thiscase->data.case_stmt.case_list, default_label); /* Get upper and lower bounds of case values. Also convert all the case values to the index expr's data type. */ uniq = 0; count = 0; for (n = thiscase->data.case_stmt.case_list; n; n = n->right) { /* Check low and high label values are integers. */ if (TREE_CODE (n->low) != INTEGER_CST) abort (); if (TREE_CODE (n->high) != INTEGER_CST) abort (); n->low = convert (index_type, n->low); n->high = convert (index_type, n->high); /* Count the elements and track the largest and smallest of them (treating them as signed even if they are not). */ if (count++ == 0) { minval = n->low; maxval = n->high; } else { if (INT_CST_LT (n->low, minval)) minval = n->low; if (INT_CST_LT (maxval, n->high)) maxval = n->high; } /* A range counts double, since it requires two compares. */ if (! tree_int_cst_equal (n->low, n->high)) count++; /* Count the number of unique case node targets. */ uniq++; lab = label_rtx (n->code_label); for (m = thiscase->data.case_stmt.case_list; m != n; m = m->right) if (same_case_target_p (label_rtx (m->code_label), lab)) { uniq--; break; } } /* Compute span of values. */ if (count != 0) range = fold (build (MINUS_EXPR, index_type, maxval, minval)); end_cleanup_deferral (); if (count == 0) { expand_expr (index_expr, const0_rtx, VOIDmode, 0); emit_queue (); emit_jump (default_label); } /* Try implementing this switch statement by a short sequence of bit-wise comparisons. However, we let the binary-tree case below handle constant index expressions. */ else if (CASE_USE_BIT_TESTS && ! TREE_CONSTANT (index_expr) && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0 && compare_tree_int (range, 0) > 0 && lshift_cheap_p () && ((uniq == 1 && count >= 3) || (uniq == 2 && count >= 5) || (uniq == 3 && count >= 6))) { /* Optimize the case where all the case values fit in a word without having to subtract MINVAL. In this case, we can optimize away the subtraction. */ if (compare_tree_int (minval, 0) > 0 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0) { minval = integer_zero_node; range = maxval; } emit_case_bit_tests (index_type, index_expr, minval, range, thiscase->data.case_stmt.case_list, default_label); } /* If range of values is much bigger than number of values, make a sequence of conditional branches instead of a dispatch. If the switch-index is a constant, do it this way because we can optimize it. */ else if (count < case_values_threshold () || compare_tree_int (range, (optimize_size ? 3 : 10) * count) > 0 /* RANGE may be signed, and really large ranges will show up as negative numbers. */ || compare_tree_int (range, 0) < 0 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT || flag_pic #endif || TREE_CONSTANT (index_expr)) { index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0); /* If the index is a short or char that we do not have an insn to handle comparisons directly, convert it to a full integer now, rather than letting each comparison generate the conversion. */ if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT && ! have_insn_for (COMPARE, GET_MODE (index))) { enum machine_mode wider_mode; for (wider_mode = GET_MODE (index); wider_mode != VOIDmode; wider_mode = GET_MODE_WIDER_MODE (wider_mode)) if (have_insn_for (COMPARE, wider_mode)) { index = convert_to_mode (wider_mode, index, unsignedp); break; } } emit_queue (); do_pending_stack_adjust (); index = protect_from_queue (index, 0); if (GET_CODE (index) == MEM) index = copy_to_reg (index); if (GET_CODE (index) == CONST_INT || TREE_CODE (index_expr) == INTEGER_CST) { /* Make a tree node with the proper constant value if we don't already have one. */ if (TREE_CODE (index_expr) != INTEGER_CST) { index_expr = build_int_2 (INTVAL (index), unsignedp || INTVAL (index) >= 0 ? 0 : -1); index_expr = convert (index_type, index_expr); } /* For constant index expressions we need only issue an unconditional branch to the appropriate target code. The job of removing any unreachable code is left to the optimization phase if the "-O" option is specified. */ for (n = thiscase->data.case_stmt.case_list; n; n = n->right) if (! tree_int_cst_lt (index_expr, n->low) && ! tree_int_cst_lt (n->high, index_expr)) break; if (n) emit_jump (label_rtx (n->code_label)); else emit_jump (default_label); } else { /* If the index expression is not constant we generate a binary decision tree to select the appropriate target code. This is done as follows: The list of cases is rearranged into a binary tree, nearly optimal assuming equal probability for each case. The tree is transformed into RTL, eliminating redundant test conditions at the same time. If program flow could reach the end of the decision tree an unconditional jump to the default code is emitted. */ use_cost_table = (TREE_CODE (orig_type) != ENUMERAL_TYPE && estimate_case_costs (thiscase->data.case_stmt.case_list)); balance_case_nodes (&thiscase->data.case_stmt.case_list, NULL); emit_case_nodes (index, thiscase->data.case_stmt.case_list, default_label, index_type); emit_jump_if_reachable (default_label); } } else { table_label = gen_label_rtx (); if (! try_casesi (index_type, index_expr, minval, range, table_label, default_label)) { index_type = thiscase->data.case_stmt.nominal_type; /* Index jumptables from zero for suitable values of minval to avoid a subtraction. */ if (! optimize_size && compare_tree_int (minval, 0) > 0 && compare_tree_int (minval, 3) < 0) { minval = integer_zero_node; range = maxval; } if (! try_tablejump (index_type, index_expr, minval, range, table_label, default_label)) abort (); } /* Get table of labels to jump to, in order of case index. */ ncases = tree_low_cst (range, 0) + 1; labelvec = alloca (ncases * sizeof (rtx)); memset (labelvec, 0, ncases * sizeof (rtx)); for (n = thiscase->data.case_stmt.case_list; n; n = n->right) { /* Compute the low and high bounds relative to the minimum value since that should fit in a HOST_WIDE_INT while the actual values may not. */ HOST_WIDE_INT i_low = tree_low_cst (fold (build (MINUS_EXPR, index_type, n->low, minval)), 1); HOST_WIDE_INT i_high = tree_low_cst (fold (build (MINUS_EXPR, index_type, n->high, minval)), 1); HOST_WIDE_INT i; for (i = i_low; i <= i_high; i ++) labelvec[i] = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label)); } /* Fill in the gaps with the default. */ for (i = 0; i < ncases; i++) if (labelvec[i] == 0) labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label); /* Output the table. */ emit_label (table_label); if (CASE_VECTOR_PC_RELATIVE || flag_pic) emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE, gen_rtx_LABEL_REF (Pmode, table_label), gen_rtvec_v (ncases, labelvec), const0_rtx, const0_rtx)); else emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE, gen_rtvec_v (ncases, labelvec))); /* If the case insn drops through the table, after the table we must jump to the default-label. Otherwise record no drop-through after the table. */ #ifdef CASE_DROPS_THROUGH emit_jump (default_label); #else emit_barrier (); #endif } before_case = NEXT_INSN (before_case); end = get_last_insn (); if (squeeze_notes (&before_case, &end)) abort (); reorder_insns (before_case, end, thiscase->data.case_stmt.start); } else end_cleanup_deferral (); if (thiscase->exit_label && !exit_done) emit_label (thiscase->exit_label); POPSTACK (case_stack); free_temp_slots (); } /* Convert the tree NODE into a list linked by the right field, with the left field zeroed. RIGHT is used for recursion; it is a list to be placed rightmost in the resulting list. */ static struct case_node * case_tree2list (struct case_node *node, struct case_node *right) { struct case_node *left; if (node->right) right = case_tree2list (node->right, right); node->right = right; if ((left = node->left)) { node->left = 0; return case_tree2list (left, node); } return node; } /* Generate code to jump to LABEL if OP1 and OP2 are equal. */ static void do_jump_if_equal (rtx op1, rtx op2, rtx label, int unsignedp) { if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT) { if (op1 == op2) emit_jump (label); } else emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX, (GET_MODE (op1) == VOIDmode ? GET_MODE (op2) : GET_MODE (op1)), unsignedp, label); } /* Not all case values are encountered equally. This function uses a heuristic to weight case labels, in cases where that looks like a reasonable thing to do. Right now, all we try to guess is text, and we establish the following weights: chars above space: 16 digits: 16 default: 12 space, punct: 8 tab: 4 newline: 2 other "\" chars: 1 remaining chars: 0 If we find any cases in the switch that are not either -1 or in the range of valid ASCII characters, or are control characters other than those commonly used with "\", don't treat this switch scanning text. Return 1 if these nodes are suitable for cost estimation, otherwise return 0. */ static int estimate_case_costs (case_node_ptr node) { tree min_ascii = integer_minus_one_node; tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0)); case_node_ptr n; int i; /* If we haven't already made the cost table, make it now. Note that the lower bound of the table is -1, not zero. */ if (! cost_table_initialized) { cost_table_initialized = 1; for (i = 0; i < 128; i++) { if (ISALNUM (i)) COST_TABLE (i) = 16; else if (ISPUNCT (i)) COST_TABLE (i) = 8; else if (ISCNTRL (i)) COST_TABLE (i) = -1; } COST_TABLE (' ') = 8; COST_TABLE ('\t') = 4; COST_TABLE ('\0') = 4; COST_TABLE ('\n') = 2; COST_TABLE ('\f') = 1; COST_TABLE ('\v') = 1; COST_TABLE ('\b') = 1; } /* See if all the case expressions look like text. It is text if the constant is >= -1 and the highest constant is <= 127. Do all comparisons as signed arithmetic since we don't want to ever access cost_table with a value less than -1. Also check that none of the constants in a range are strange control characters. */ for (n = node; n; n = n->right) { if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high)) return 0; for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low); i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++) if (COST_TABLE (i) < 0) return 0; } /* All interesting values are within the range of interesting ASCII characters. */ return 1; } /* Determine whether two case labels branch to the same target. */ static bool same_case_target_p (rtx l1, rtx l2) { rtx i1, i2; if (l1 == l2) return true; i1 = next_real_insn (l1); i2 = next_real_insn (l2); if (i1 == i2) return true; if (i1 && simplejump_p (i1)) { l1 = XEXP (SET_SRC (PATTERN (i1)), 0); } if (i2 && simplejump_p (i2)) { l2 = XEXP (SET_SRC (PATTERN (i2)), 0); } return l1 == l2; } /* Delete nodes that branch to the default label from a list of case nodes. Eg. case 5: default: becomes just default: */ static void strip_default_case_nodes (case_node_ptr *prev, rtx deflab) { case_node_ptr ptr; while (*prev) { ptr = *prev; if (same_case_target_p (label_rtx (ptr->code_label), deflab)) *prev = ptr->right; else prev = &ptr->right; } } /* Scan an ordered list of case nodes combining those with consecutive values or ranges. Eg. three separate entries 1: 2: 3: become one entry 1..3: */ static void group_case_nodes (case_node_ptr head) { case_node_ptr node = head; while (node) { rtx lab = label_rtx (node->code_label); case_node_ptr np = node; /* Try to group the successors of NODE with NODE. */ while (((np = np->right) != 0) /* Do they jump to the same place? */ && same_case_target_p (label_rtx (np->code_label), lab) /* Are their ranges consecutive? */ && tree_int_cst_equal (np->low, fold (build (PLUS_EXPR, TREE_TYPE (node->high), node->high, integer_one_node))) /* An overflow is not consecutive. */ && tree_int_cst_lt (node->high, fold (build (PLUS_EXPR, TREE_TYPE (node->high), node->high, integer_one_node)))) { node->high = np->high; } /* NP is the first node after NODE which can't be grouped with it. Delete the nodes in between, and move on to that node. */ node->right = np; node = np; } } /* Take an ordered list of case nodes and transform them into a near optimal binary tree, on the assumption that any target code selection value is as likely as any other. The transformation is performed by splitting the ordered list into two equal sections plus a pivot. The parts are then attached to the pivot as left and right branches. Each branch is then transformed recursively. */ static void balance_case_nodes (case_node_ptr *head, case_node_ptr parent) { case_node_ptr np; np = *head; if (np) { int cost = 0; int i = 0; int ranges = 0; case_node_ptr *npp; case_node_ptr left; /* Count the number of entries on branch. Also count the ranges. */ while (np) { if (!tree_int_cst_equal (np->low, np->high)) { ranges++; if (use_cost_table) cost += COST_TABLE (TREE_INT_CST_LOW (np->high)); } if (use_cost_table) cost += COST_TABLE (TREE_INT_CST_LOW (np->low)); i++; np = np->right; } if (i > 2) { /* Split this list if it is long enough for that to help. */ npp = head; left = *npp; if (use_cost_table) { /* Find the place in the list that bisects the list's total cost, Here I gets half the total cost. */ int n_moved = 0; i = (cost + 1) / 2; while (1) { /* Skip nodes while their cost does not reach that amount. */ if (!tree_int_cst_equal ((*npp)->low, (*npp)->high)) i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high)); i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low)); if (i <= 0) break; npp = &(*npp)->right; n_moved += 1; } if (n_moved == 0) { /* Leave this branch lopsided, but optimize left-hand side and fill in `parent' fields for right-hand side. */ np = *head; np->parent = parent; balance_case_nodes (&np->left, np); for (; np->right; np = np->right) np->right->parent = np; return; } } /* If there are just three nodes, split at the middle one. */ else if (i == 3) npp = &(*npp)->right; else { /* Find the place in the list that bisects the list's total cost, where ranges count as 2. Here I gets half the total cost. */ i = (i + ranges + 1) / 2; while (1) { /* Skip nodes while their cost does not reach that amount. */ if (!tree_int_cst_equal ((*npp)->low, (*npp)->high)) i--; i--; if (i <= 0) break; npp = &(*npp)->right; } } *head = np = *npp; *npp = 0; np->parent = parent; np->left = left; /* Optimize each of the two split parts. */ balance_case_nodes (&np->left, np); balance_case_nodes (&np->right, np); } else { /* Else leave this branch as one level, but fill in `parent' fields. */ np = *head; np->parent = parent; for (; np->right; np = np->right) np->right->parent = np; } } } /* Search the parent sections of the case node tree to see if a test for the lower bound of NODE would be redundant. INDEX_TYPE is the type of the index expression. The instructions to generate the case decision tree are output in the same order as nodes are processed so it is known that if a parent node checks the range of the current node minus one that the current node is bounded at its lower span. Thus the test would be redundant. */ static int node_has_low_bound (case_node_ptr node, tree index_type) { tree low_minus_one; case_node_ptr pnode; /* If the lower bound of this node is the lowest value in the index type, we need not test it. */ if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type))) return 1; /* If this node has a left branch, the value at the left must be less than that at this node, so it cannot be bounded at the bottom and we need not bother testing any further. */ if (node->left) return 0; low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low), node->low, integer_one_node)); /* If the subtraction above overflowed, we can't verify anything. Otherwise, look for a parent that tests our value - 1. */ if (! tree_int_cst_lt (low_minus_one, node->low)) return 0; for (pnode = node->parent; pnode; pnode = pnode->parent) if (tree_int_cst_equal (low_minus_one, pnode->high)) return 1; return 0; } /* Search the parent sections of the case node tree to see if a test for the upper bound of NODE would be redundant. INDEX_TYPE is the type of the index expression. The instructions to generate the case decision tree are output in the same order as nodes are processed so it is known that if a parent node checks the range of the current node plus one that the current node is bounded at its upper span. Thus the test would be redundant. */ static int node_has_high_bound (case_node_ptr node, tree index_type) { tree high_plus_one; case_node_ptr pnode; /* If there is no upper bound, obviously no test is needed. */ if (TYPE_MAX_VALUE (index_type) == NULL) return 1; /* If the upper bound of this node is the highest value in the type of the index expression, we need not test against it. */ if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type))) return 1; /* If this node has a right branch, the value at the right must be greater than that at this node, so it cannot be bounded at the top and we need not bother testing any further. */ if (node->right) return 0; high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high), node->high, integer_one_node)); /* If the addition above overflowed, we can't verify anything. Otherwise, look for a parent that tests our value + 1. */ if (! tree_int_cst_lt (node->high, high_plus_one)) return 0; for (pnode = node->parent; pnode; pnode = pnode->parent) if (tree_int_cst_equal (high_plus_one, pnode->low)) return 1; return 0; } /* Search the parent sections of the case node tree to see if both tests for the upper and lower bounds of NODE would be redundant. */ static int node_is_bounded (case_node_ptr node, tree index_type) { return (node_has_low_bound (node, index_type) && node_has_high_bound (node, index_type)); } /* Emit an unconditional jump to LABEL unless it would be dead code. */ static void emit_jump_if_reachable (rtx label) { if (GET_CODE (get_last_insn ()) != BARRIER) emit_jump (label); } /* Emit step-by-step code to select a case for the value of INDEX. The thus generated decision tree follows the form of the case-node binary tree NODE, whose nodes represent test conditions. INDEX_TYPE is the type of the index of the switch. Care is taken to prune redundant tests from the decision tree by detecting any boundary conditions already checked by emitted rtx. (See node_has_high_bound, node_has_low_bound and node_is_bounded, above.) Where the test conditions can be shown to be redundant we emit an unconditional jump to the target code. As a further optimization, the subordinates of a tree node are examined to check for bounded nodes. In this case conditional and/or unconditional jumps as a result of the boundary check for the current node are arranged to target the subordinates associated code for out of bound conditions on the current node. We can assume that when control reaches the code generated here, the index value has already been compared with the parents of this node, and determined to be on the same side of each parent as this node is. Thus, if this node tests for the value 51, and a parent tested for 52, we don't need to consider the possibility of a value greater than 51. If another parent tests for the value 50, then this node need not test anything. */ static void emit_case_nodes (rtx index, case_node_ptr node, rtx default_label, tree index_type) { /* If INDEX has an unsigned type, we must make unsigned branches. */ int unsignedp = TREE_UNSIGNED (index_type); enum machine_mode mode = GET_MODE (index); enum machine_mode imode = TYPE_MODE (index_type); /* See if our parents have already tested everything for us. If they have, emit an unconditional jump for this node. */ if (node_is_bounded (node, index_type)) emit_jump (label_rtx (node->code_label)); else if (tree_int_cst_equal (node->low, node->high)) { /* Node is single valued. First see if the index expression matches this node and then check our children, if any. */ do_jump_if_equal (index, convert_modes (mode, imode, expand_expr (node->low, NULL_RTX, VOIDmode, 0), unsignedp), label_rtx (node->code_label), unsignedp); if (node->right != 0 && node->left != 0) { /* This node has children on both sides. Dispatch to one side or the other by comparing the index value with this node's value. If one subtree is bounded, check that one first, so we can avoid real branches in the tree. */ if (node_is_bounded (node->right, index_type)) { emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->high, NULL_RTX, VOIDmode, 0), unsignedp), GT, NULL_RTX, mode, unsignedp, label_rtx (node->right->code_label)); emit_case_nodes (index, node->left, default_label, index_type); } else if (node_is_bounded (node->left, index_type)) { emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->high, NULL_RTX, VOIDmode, 0), unsignedp), LT, NULL_RTX, mode, unsignedp, label_rtx (node->left->code_label)); emit_case_nodes (index, node->right, default_label, index_type); } else { /* Neither node is bounded. First distinguish the two sides; then emit the code for one side at a time. */ tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE); /* See if the value is on the right. */ emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->high, NULL_RTX, VOIDmode, 0), unsignedp), GT, NULL_RTX, mode, unsignedp, label_rtx (test_label)); /* Value must be on the left. Handle the left-hand subtree. */ emit_case_nodes (index, node->left, default_label, index_type); /* If left-hand subtree does nothing, go to default. */ emit_jump_if_reachable (default_label); /* Code branches here for the right-hand subtree. */ expand_label (test_label); emit_case_nodes (index, node->right, default_label, index_type); } } else if (node->right != 0 && node->left == 0) { /* Here we have a right child but no left so we issue conditional branch to default and process the right child. Omit the conditional branch to default if we it avoid only one right child; it costs too much space to save so little time. */ if (node->right->right || node->right->left || !tree_int_cst_equal (node->right->low, node->right->high)) { if (!node_has_low_bound (node, index_type)) { emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->high, NULL_RTX, VOIDmode, 0), unsignedp), LT, NULL_RTX, mode, unsignedp, default_label); } emit_case_nodes (index, node->right, default_label, index_type); } else /* We cannot process node->right normally since we haven't ruled out the numbers less than this node's value. So handle node->right explicitly. */ do_jump_if_equal (index, convert_modes (mode, imode, expand_expr (node->right->low, NULL_RTX, VOIDmode, 0), unsignedp), label_rtx (node->right->code_label), unsignedp); } else if (node->right == 0 && node->left != 0) { /* Just one subtree, on the left. */ if (node->left->left || node->left->right || !tree_int_cst_equal (node->left->low, node->left->high)) { if (!node_has_high_bound (node, index_type)) { emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->high, NULL_RTX, VOIDmode, 0), unsignedp), GT, NULL_RTX, mode, unsignedp, default_label); } emit_case_nodes (index, node->left, default_label, index_type); } else /* We cannot process node->left normally since we haven't ruled out the numbers less than this node's value. So handle node->left explicitly. */ do_jump_if_equal (index, convert_modes (mode, imode, expand_expr (node->left->low, NULL_RTX, VOIDmode, 0), unsignedp), label_rtx (node->left->code_label), unsignedp); } } else { /* Node is a range. These cases are very similar to those for a single value, except that we do not start by testing whether this node is the one to branch to. */ if (node->right != 0 && node->left != 0) { /* Node has subtrees on both sides. If the right-hand subtree is bounded, test for it first, since we can go straight there. Otherwise, we need to make a branch in the control structure, then handle the two subtrees. */ tree test_label = 0; if (node_is_bounded (node->right, index_type)) /* Right hand node is fully bounded so we can eliminate any testing and branch directly to the target code. */ emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->high, NULL_RTX, VOIDmode, 0), unsignedp), GT, NULL_RTX, mode, unsignedp, label_rtx (node->right->code_label)); else { /* Right hand node requires testing. Branch to a label where we will handle it later. */ test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE); emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->high, NULL_RTX, VOIDmode, 0), unsignedp), GT, NULL_RTX, mode, unsignedp, label_rtx (test_label)); } /* Value belongs to this node or to the left-hand subtree. */ emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->low, NULL_RTX, VOIDmode, 0), unsignedp), GE, NULL_RTX, mode, unsignedp, label_rtx (node->code_label)); /* Handle the left-hand subtree. */ emit_case_nodes (index, node->left, default_label, index_type); /* If right node had to be handled later, do that now. */ if (test_label) { /* If the left-hand subtree fell through, don't let it fall into the right-hand subtree. */ emit_jump_if_reachable (default_label); expand_label (test_label); emit_case_nodes (index, node->right, default_label, index_type); } } else if (node->right != 0 && node->left == 0) { /* Deal with values to the left of this node, if they are possible. */ if (!node_has_low_bound (node, index_type)) { emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->low, NULL_RTX, VOIDmode, 0), unsignedp), LT, NULL_RTX, mode, unsignedp, default_label); } /* Value belongs to this node or to the right-hand subtree. */ emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->high, NULL_RTX, VOIDmode, 0), unsignedp), LE, NULL_RTX, mode, unsignedp, label_rtx (node->code_label)); emit_case_nodes (index, node->right, default_label, index_type); } else if (node->right == 0 && node->left != 0) { /* Deal with values to the right of this node, if they are possible. */ if (!node_has_high_bound (node, index_type)) { emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->high, NULL_RTX, VOIDmode, 0), unsignedp), GT, NULL_RTX, mode, unsignedp, default_label); } /* Value belongs to this node or to the left-hand subtree. */ emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->low, NULL_RTX, VOIDmode, 0), unsignedp), GE, NULL_RTX, mode, unsignedp, label_rtx (node->code_label)); emit_case_nodes (index, node->left, default_label, index_type); } else { /* Node has no children so we check low and high bounds to remove redundant tests. Only one of the bounds can exist, since otherwise this node is bounded--a case tested already. */ int high_bound = node_has_high_bound (node, index_type); int low_bound = node_has_low_bound (node, index_type); if (!high_bound && low_bound) { emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->high, NULL_RTX, VOIDmode, 0), unsignedp), GT, NULL_RTX, mode, unsignedp, default_label); } else if (!low_bound && high_bound) { emit_cmp_and_jump_insns (index, convert_modes (mode, imode, expand_expr (node->low, NULL_RTX, VOIDmode, 0), unsignedp), LT, NULL_RTX, mode, unsignedp, default_label); } else if (!low_bound && !high_bound) { /* Widen LOW and HIGH to the same width as INDEX. */ tree type = (*lang_hooks.types.type_for_mode) (mode, unsignedp); tree low = build1 (CONVERT_EXPR, type, node->low); tree high = build1 (CONVERT_EXPR, type, node->high); rtx low_rtx, new_index, new_bound; /* Instead of doing two branches, emit one unsigned branch for (index-low) > (high-low). */ low_rtx = expand_expr (low, NULL_RTX, mode, 0); new_index = expand_simple_binop (mode, MINUS, index, low_rtx, NULL_RTX, unsignedp, OPTAB_WIDEN); new_bound = expand_expr (fold (build (MINUS_EXPR, type, high, low)), NULL_RTX, mode, 0); emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX, mode, 1, default_label); } emit_jump (label_rtx (node->code_label)); } } } #include "gt-stmt.h"