1 /* Tree lowering pass. This pass gimplifies the tree representation built
2 by the C-based front ends. The structure of gimplified, or
3 language-independent, trees is dictated by the grammar described in this
5 Copyright (C) 2002-2015 Free Software Foundation, Inc.
6 Lowering of expressions contributed by Sebastian Pop <s.pop@laposte.net>
7 Re-written to support lowering of whole function trees, documentation
8 and miscellaneous cleanups by Diego Novillo <dnovillo@redhat.com>
10 This file is part of GCC.
12 GCC is free software; you can redistribute it and/or modify it under
13 the terms of the GNU General Public License as published by the Free
14 Software Foundation; either version 3, or (at your option) any later
17 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
18 WARRANTY; without even the implied warranty of MERCHANTABILITY or
19 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
22 You should have received a copy of the GNU General Public License
23 along with GCC; see the file COPYING3. If not see
24 <http://www.gnu.org/licenses/>. */
28 #include "coretypes.h"
33 #include "double-int.h"
40 #include "fold-const.h"
47 #include "hard-reg-set.h"
50 #include "basic-block.h"
51 #include "tree-ssa-alias.h"
52 #include "internal-fn.h"
53 #include "gimple-expr.h"
57 #include "tree-inline.h"
58 #include "diagnostic-core.h"
59 #include "langhooks.h"
60 #include "langhooks-def.h"
63 #include "c-pretty-print.h"
65 #include "plugin-api.h"
71 /* The gimplification pass converts the language-dependent trees
72 (ld-trees) emitted by the parser into language-independent trees
73 (li-trees) that are the target of SSA analysis and transformations.
75 Language-independent trees are based on the SIMPLE intermediate
76 representation used in the McCAT compiler framework:
78 "Designing the McCAT Compiler Based on a Family of Structured
79 Intermediate Representations,"
80 L. Hendren, C. Donawa, M. Emami, G. Gao, Justiani, and B. Sridharan,
81 Proceedings of the 5th International Workshop on Languages and
82 Compilers for Parallel Computing, no. 757 in Lecture Notes in
83 Computer Science, New Haven, Connecticut, pp. 406-420,
84 Springer-Verlag, August 3-5, 1992.
86 http://www-acaps.cs.mcgill.ca/info/McCAT/McCAT.html
88 Basically, we walk down gimplifying the nodes that we encounter. As we
89 walk back up, we check that they fit our constraints, and copy them
90 into temporaries if not. */
92 /* Callback for c_genericize. */
95 ubsan_walk_array_refs_r (tree *tp, int *walk_subtrees, void *data)
97 hash_set<tree> *pset = (hash_set<tree> *) data;
99 /* Since walk_tree doesn't call the callback function on the decls
100 in BIND_EXPR_VARS, we have to walk them manually. */
101 if (TREE_CODE (*tp) == BIND_EXPR)
103 for (tree decl = BIND_EXPR_VARS (*tp); decl; decl = DECL_CHAIN (decl))
105 if (TREE_STATIC (decl))
110 walk_tree (&DECL_INITIAL (decl), ubsan_walk_array_refs_r, pset,
112 walk_tree (&DECL_SIZE (decl), ubsan_walk_array_refs_r, pset, pset);
113 walk_tree (&DECL_SIZE_UNIT (decl), ubsan_walk_array_refs_r, pset,
117 else if (TREE_CODE (*tp) == ADDR_EXPR
118 && TREE_CODE (TREE_OPERAND (*tp, 0)) == ARRAY_REF)
120 ubsan_maybe_instrument_array_ref (&TREE_OPERAND (*tp, 0), true);
121 /* Make sure ubsan_maybe_instrument_array_ref is not called again
122 on the ARRAY_REF, the above call might not instrument anything
123 as the index might be constant or masked, so ensure it is not
124 walked again and walk its subtrees manually. */
125 tree aref = TREE_OPERAND (*tp, 0);
128 walk_tree (&TREE_OPERAND (aref, 0), ubsan_walk_array_refs_r, pset, pset);
129 walk_tree (&TREE_OPERAND (aref, 1), ubsan_walk_array_refs_r, pset, pset);
130 walk_tree (&TREE_OPERAND (aref, 2), ubsan_walk_array_refs_r, pset, pset);
131 walk_tree (&TREE_OPERAND (aref, 3), ubsan_walk_array_refs_r, pset, pset);
133 else if (TREE_CODE (*tp) == ARRAY_REF)
134 ubsan_maybe_instrument_array_ref (tp, false);
138 /* Gimplification of statement trees. */
140 /* Convert the tree representation of FNDECL from C frontend trees to
144 c_genericize (tree fndecl)
147 int local_dump_flags;
148 struct cgraph_node *cgn;
150 if (flag_sanitize & SANITIZE_BOUNDS)
153 walk_tree (&DECL_SAVED_TREE (fndecl), ubsan_walk_array_refs_r, &pset,
157 /* Dump the C-specific tree IR. */
158 dump_orig = get_dump_info (TDI_original, &local_dump_flags);
161 fprintf (dump_orig, "\n;; Function %s",
162 lang_hooks.decl_printable_name (fndecl, 2));
163 fprintf (dump_orig, " (%s)\n",
164 (!DECL_ASSEMBLER_NAME_SET_P (fndecl) ? "null"
165 : IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (fndecl))));
166 fprintf (dump_orig, ";; enabled by -%s\n", dump_flag_name (TDI_original));
167 fprintf (dump_orig, "\n");
169 if (local_dump_flags & TDF_RAW)
170 dump_node (DECL_SAVED_TREE (fndecl),
171 TDF_SLIM | local_dump_flags, dump_orig);
173 print_c_tree (dump_orig, DECL_SAVED_TREE (fndecl));
174 fprintf (dump_orig, "\n");
177 /* Dump all nested functions now. */
178 cgn = cgraph_node::get_create (fndecl);
179 for (cgn = cgn->nested; cgn ; cgn = cgn->next_nested)
180 c_genericize (cgn->decl);
184 add_block_to_enclosing (tree block)
189 vec<gbind *> stack = gimple_bind_expr_stack ();
191 FOR_EACH_VEC_ELT (stack, i, bind)
192 if (gimple_bind_block (bind))
195 enclosing = gimple_bind_block (bind);
196 BLOCK_SUBBLOCKS (enclosing) = chainon (BLOCK_SUBBLOCKS (enclosing), block);
199 /* Genericize a scope by creating a new BIND_EXPR.
200 BLOCK is either a BLOCK representing the scope or a chain of _DECLs.
201 In the latter case, we need to create a new BLOCK and add it to the
202 BLOCK_SUBBLOCKS of the enclosing block.
203 BODY is a chain of C _STMT nodes for the contents of the scope, to be
207 c_build_bind_expr (location_t loc, tree block, tree body)
211 if (block == NULL_TREE)
213 else if (TREE_CODE (block) == BLOCK)
214 decls = BLOCK_VARS (block);
218 if (DECL_ARTIFICIAL (decls))
222 block = make_node (BLOCK);
223 BLOCK_VARS (block) = decls;
224 add_block_to_enclosing (block);
229 body = build_empty_stmt (loc);
232 bind = build3 (BIND_EXPR, void_type_node, decls, body, block);
233 TREE_SIDE_EFFECTS (bind) = 1;
234 SET_EXPR_LOCATION (bind, loc);
242 /* Gimplification of expression trees. */
244 /* Do C-specific gimplification on *EXPR_P. PRE_P and POST_P are as in
248 c_gimplify_expr (tree *expr_p, gimple_seq *pre_p ATTRIBUTE_UNUSED,
249 gimple_seq *post_p ATTRIBUTE_UNUSED)
251 enum tree_code code = TREE_CODE (*expr_p);
258 /* We used to convert the right operand of a shift-expression
259 to an integer_type_node in the FEs. But it is unnecessary
260 and not desirable for diagnostics and sanitizers. We keep
261 this here to not pessimize the code, but we convert to an
262 unsigned type, because negative shift counts are undefined
264 We should get rid of this conversion when we have a proper
265 type demotion/promotion pass. */
266 tree *op1_p = &TREE_OPERAND (*expr_p, 1);
267 if (TREE_CODE (TREE_TYPE (*op1_p)) != VECTOR_TYPE
268 && !types_compatible_p (TYPE_MAIN_VARIANT (TREE_TYPE (*op1_p)),
270 && !types_compatible_p (TYPE_MAIN_VARIANT (TREE_TYPE (*op1_p)),
272 *op1_p = convert (unsigned_type_node, *op1_p);
277 /* This is handled mostly by gimplify.c, but we have to deal with
278 not warning about int x = x; as it is a GCC extension to turn off
279 this warning but only if warn_init_self is zero. */
280 if (TREE_CODE (DECL_EXPR_DECL (*expr_p)) == VAR_DECL
281 && !DECL_EXTERNAL (DECL_EXPR_DECL (*expr_p))
282 && !TREE_STATIC (DECL_EXPR_DECL (*expr_p))
283 && (DECL_INITIAL (DECL_EXPR_DECL (*expr_p)) == DECL_EXPR_DECL (*expr_p))
285 TREE_NO_WARNING (DECL_EXPR_DECL (*expr_p)) = 1;
288 case PREINCREMENT_EXPR:
289 case PREDECREMENT_EXPR:
290 case POSTINCREMENT_EXPR:
291 case POSTDECREMENT_EXPR:
293 tree type = TREE_TYPE (TREE_OPERAND (*expr_p, 0));
294 if (INTEGRAL_TYPE_P (type) && c_promoting_integer_type_p (type))
296 if (!TYPE_OVERFLOW_WRAPS (type))
297 type = unsigned_type_for (type);
298 return gimplify_self_mod_expr (expr_p, pre_p, post_p, 1, type);
303 case CILK_SPAWN_STMT:
305 (fn_contains_cilk_spawn_p (cfun)
306 && cilk_detect_spawn_and_unwrap (expr_p));
308 /* If errors are seen, then just process it as a CALL_EXPR. */
310 return (enum gimplify_status) gimplify_cilk_spawn (expr_p);
315 if (fn_contains_cilk_spawn_p (cfun)
316 && cilk_detect_spawn_and_unwrap (expr_p)
317 /* If an error is found, the spawn wrapper is removed and the
318 original expression (MODIFY/INIT/CALL_EXPR) is processes as
319 it is supposed to be. */
321 return (enum gimplify_status) gimplify_cilk_spawn (expr_p);