Upgrade GDB from 7.4.1 to 7.6.1 on the vendor branch
[dragonfly.git] / contrib / gdb-7 / gdb / ax.h
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5796c8dc 1/* Definitions for expressions designed to be executed on the agent
ef5ccd6c 2 Copyright (C) 1998-2013 Free Software Foundation, Inc.
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3
4 This file is part of GDB.
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
18
19#ifndef AGENTEXPR_H
20#define AGENTEXPR_H
21
22#include "doublest.h" /* For DOUBLEST. */
ef5ccd6c 23#include "vec.h"
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24
25/* It's sometimes useful to be able to debug programs that you can't
26 really stop for more than a fraction of a second. To this end, the
27 user can specify a tracepoint (like a breakpoint, but you don't
28 stop at it), and specify a bunch of expressions to record the
29 values of when that tracepoint is reached. As the program runs,
30 GDB collects the values. At any point (possibly while values are
31 still being collected), the user can display the collected values.
32
33 This is used with remote debugging; we don't really support it on
34 native configurations.
35
36 This means that expressions are being evaluated by the remote agent,
37 which doesn't have any access to the symbol table information, and
38 needs to be small and simple.
39
40 The agent_expr routines and datatypes are a bytecode language
41 designed to be executed by the agent. Agent expressions work in
42 terms of fixed-width values, operators, memory references, and
43 register references. You can evaluate a agent expression just given
44 a bunch of memory and register values to sniff at; you don't need
45 any symbolic information like variable names, types, etc.
46
47 GDB translates source expressions, whose meaning depends on
48 symbolic information, into agent bytecode expressions, whose meaning
49 is independent of symbolic information. This means the agent can
50 evaluate them on the fly without reference to data only available
51 to the host GDB. */
52\f
53
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54/* Different kinds of flaws an agent expression might have, as
55 detected by ax_reqs. */
56enum agent_flaws
57 {
58 agent_flaw_none = 0, /* code is good */
59
60 /* There is an invalid instruction in the stream. */
61 agent_flaw_bad_instruction,
62
63 /* There is an incomplete instruction at the end of the expression. */
64 agent_flaw_incomplete_instruction,
65
66 /* ax_reqs was unable to prove that every jump target is to a
67 valid offset. Valid offsets are within the bounds of the
68 expression, and to a valid instruction boundary. */
69 agent_flaw_bad_jump,
70
71 /* ax_reqs was unable to prove to its satisfaction that, for each
72 jump target location, the stack will have the same height whether
73 that location is reached via a jump or by straight execution. */
74 agent_flaw_height_mismatch,
75
76 /* ax_reqs was unable to prove that every instruction following
77 an unconditional jump was the target of some other jump. */
78 agent_flaw_hole
79 };
80
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81/* Agent expression data structures. */
82
83/* The type of an element of the agent expression stack.
84 The bytecode operation indicates which element we should access;
85 the value itself has no typing information. GDB generates all
86 bytecode streams, so we don't have to worry about type errors. */
87
88union agent_val
89 {
90 LONGEST l;
91 DOUBLEST d;
92 };
93
94/* A buffer containing a agent expression. */
95struct agent_expr
96 {
cf7f2e2d 97 /* The bytes of the expression. */
5796c8dc 98 unsigned char *buf;
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99
100 /* The number of bytecode in the expression. */
101 int len;
102
103 /* Allocated space available currently. */
104 int size;
105
106 /* The target architecture assumed to be in effect. */
107 struct gdbarch *gdbarch;
108
109 /* The address to which the expression applies. */
5796c8dc 110 CORE_ADDR scope;
5796c8dc 111
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112 /* If the following is not equal to agent_flaw_none, the rest of the
113 information in this structure is suspect. */
114 enum agent_flaws flaw;
115
116 /* Number of elements left on stack at end; may be negative if expr
117 only consumes elements. */
118 int final_height;
119
120 /* Maximum and minimum stack height, relative to initial height. */
121 int max_height, min_height;
122
123 /* Largest `ref' or `const' opcode used, in bits. Zero means the
124 expression has no such instructions. */
125 int max_data_size;
126
127 /* Bit vector of registers needed. Register R is needed iff
5796c8dc 128
cf7f2e2d 129 reg_mask[R / 8] & (1 << (R % 8))
5796c8dc 130
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131 is non-zero. Note! You may not assume that this bitmask is long
132 enough to hold bits for all the registers of the machine; the
133 agent expression code has no idea how many registers the machine
134 has. However, the bitmask is reg_mask_len bytes long, so the
135 valid register numbers run from 0 to reg_mask_len * 8 - 1.
136
137 Also note that this mask may contain registers that are needed
138 for the original collection expression to work, but that are
139 not referenced by any bytecode. This could, for example, occur
140 when collecting a local variable allocated to a register; the
141 compiler sets the mask bit and skips generating a bytecode whose
142 result is going to be discarded anyway.
143 */
144 int reg_mask_len;
145 unsigned char *reg_mask;
146 };
5796c8dc 147
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148/* Pointer to an agent_expr structure. */
149typedef struct agent_expr *agent_expr_p;
150
151/* Vector of pointers to agent expressions. */
152DEF_VEC_P (agent_expr_p);
153
c50c785c 154/* The actual values of the various bytecode operations. */
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155
156enum agent_op
157 {
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158#define DEFOP(NAME, SIZE, DATA_SIZE, CONSUMED, PRODUCED, VALUE) \
159 aop_ ## NAME = VALUE,
160#include "ax.def"
161#undef DEFOP
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162 aop_last
163 };
164\f
165
166
167/* Functions for building expressions. */
168
169/* Allocate a new, empty agent expression. */
cf7f2e2d 170extern struct agent_expr *new_agent_expr (struct gdbarch *, CORE_ADDR);
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171
172/* Free a agent expression. */
173extern void free_agent_expr (struct agent_expr *);
174extern struct cleanup *make_cleanup_free_agent_expr (struct agent_expr *);
175
176/* Append a simple operator OP to EXPR. */
177extern void ax_simple (struct agent_expr *EXPR, enum agent_op OP);
178
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179/* Append a pick operator to EXPR. DEPTH is the stack item to pick,
180 with 0 being top of stack. */
181extern void ax_pick (struct agent_expr *EXPR, int DEPTH);
182
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183/* Append the floating-point prefix, for the next bytecode. */
184#define ax_float(EXPR) (ax_simple ((EXPR), aop_float))
185
186/* Append a sign-extension instruction to EXPR, to extend an N-bit value. */
187extern void ax_ext (struct agent_expr *EXPR, int N);
188
189/* Append a zero-extension instruction to EXPR, to extend an N-bit value. */
190extern void ax_zero_ext (struct agent_expr *EXPR, int N);
191
192/* Append a trace_quick instruction to EXPR, to record N bytes. */
193extern void ax_trace_quick (struct agent_expr *EXPR, int N);
194
195/* Append a goto op to EXPR. OP is the actual op (must be aop_goto or
196 aop_if_goto). We assume we don't know the target offset yet,
197 because it's probably a forward branch, so we leave space in EXPR
198 for the target, and return the offset in EXPR of that space, so we
199 can backpatch it once we do know the target offset. Use ax_label
200 to do the backpatching. */
201extern int ax_goto (struct agent_expr *EXPR, enum agent_op OP);
202
203/* Suppose a given call to ax_goto returns some value PATCH. When you
204 know the offset TARGET that goto should jump to, call
205 ax_label (EXPR, PATCH, TARGET)
206 to patch TARGET into the ax_goto instruction. */
207extern void ax_label (struct agent_expr *EXPR, int patch, int target);
208
209/* Assemble code to push a constant on the stack. */
210extern void ax_const_l (struct agent_expr *EXPR, LONGEST l);
211extern void ax_const_d (struct agent_expr *EXPR, LONGEST d);
212
213/* Assemble code to push the value of register number REG on the
214 stack. */
215extern void ax_reg (struct agent_expr *EXPR, int REG);
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216
217/* Add the given register to the register mask of the expression. */
218extern void ax_reg_mask (struct agent_expr *ax, int reg);
219
220/* Assemble code to operate on a trace state variable. */
221extern void ax_tsv (struct agent_expr *expr, enum agent_op op, int num);
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222
223/* Append a string to the bytecode stream. */
224extern void ax_string (struct agent_expr *x, const char *str, int slen);
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225\f
226
227/* Functions for printing out expressions, and otherwise debugging
228 things. */
229
230/* Disassemble the expression EXPR, writing to F. */
231extern void ax_print (struct ui_file *f, struct agent_expr * EXPR);
232
233/* An entry in the opcode map. */
234struct aop_map
235 {
236
237 /* The name of the opcode. Null means that this entry is not a
238 valid opcode --- a hole in the opcode space. */
c50c785c 239 const char *name;
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240
241 /* All opcodes take no operands from the bytecode stream, or take
242 unsigned integers of various sizes. If this is a positive number
243 n, then the opcode is followed by an n-byte operand, which should
244 be printed as an unsigned integer. If this is zero, then the
245 opcode takes no operands from the bytecode stream.
246
247 If we get more complicated opcodes in the future, don't add other
248 magic values of this; that's a crock. Add an `enum encoding'
249 field to this, or something like that. */
250 int op_size;
251
252 /* The size of the data operated upon, in bits, for bytecodes that
253 care about that (ref and const). Zero for all others. */
254 int data_size;
255
256 /* Number of stack elements consumed, and number produced. */
257 int consumed, produced;
258 };
259
260/* Map of the bytecodes, indexed by bytecode number. */
261extern struct aop_map aop_map[];
262
cf7f2e2d 263/* Given an agent expression AX, analyze and update its requirements. */
5796c8dc 264
cf7f2e2d 265extern void ax_reqs (struct agent_expr *ax);
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266
267#endif /* AGENTEXPR_H */