Import gdb 7.3 into vendor branch
[dragonfly.git] / contrib / gdb-7 / gdb / ax-general.c
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5796c8dc 1/* Functions for manipulating expressions designed to be executed on the agent
c50c785c 2 Copyright (C) 1998, 1999, 2000, 2007, 2008, 2009, 2010, 2011
5796c8dc
SS
3 Free Software Foundation, Inc.
4
5 This file is part of GDB.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19
20/* Despite what the above comment says about this file being part of
21 GDB, we would like to keep these functions free of GDB
22 dependencies, since we want to be able to use them in contexts
23 outside of GDB (test suites, the stub, etc.) */
24
25#include "defs.h"
26#include "ax.h"
27
28#include "value.h"
29#include "gdb_string.h"
30
c50c785c
JM
31#include "user-regs.h"
32
5796c8dc
SS
33static void grow_expr (struct agent_expr *x, int n);
34
35static void append_const (struct agent_expr *x, LONGEST val, int n);
36
37static LONGEST read_const (struct agent_expr *x, int o, int n);
38
39static void generic_ext (struct agent_expr *x, enum agent_op op, int n);
40\f
41/* Functions for building expressions. */
42
43/* Allocate a new, empty agent expression. */
44struct agent_expr *
cf7f2e2d 45new_agent_expr (struct gdbarch *gdbarch, CORE_ADDR scope)
5796c8dc
SS
46{
47 struct agent_expr *x = xmalloc (sizeof (*x));
cf7f2e2d 48
5796c8dc
SS
49 x->len = 0;
50 x->size = 1; /* Change this to a larger value once
51 reallocation code is tested. */
52 x->buf = xmalloc (x->size);
cf7f2e2d
JM
53
54 x->gdbarch = gdbarch;
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55 x->scope = scope;
56
cf7f2e2d
JM
57 /* Bit vector for registers used. */
58 x->reg_mask_len = 1;
59 x->reg_mask = xmalloc (x->reg_mask_len * sizeof (x->reg_mask[0]));
60 memset (x->reg_mask, 0, x->reg_mask_len * sizeof (x->reg_mask[0]));
61
5796c8dc
SS
62 return x;
63}
64
65/* Free a agent expression. */
66void
67free_agent_expr (struct agent_expr *x)
68{
69 xfree (x->buf);
cf7f2e2d 70 xfree (x->reg_mask);
5796c8dc
SS
71 xfree (x);
72}
73
74static void
75do_free_agent_expr_cleanup (void *x)
76{
77 free_agent_expr (x);
78}
79
80struct cleanup *
81make_cleanup_free_agent_expr (struct agent_expr *x)
82{
83 return make_cleanup (do_free_agent_expr_cleanup, x);
84}
85
86
87/* Make sure that X has room for at least N more bytes. This doesn't
88 affect the length, just the allocated size. */
89static void
90grow_expr (struct agent_expr *x, int n)
91{
92 if (x->len + n > x->size)
93 {
94 x->size *= 2;
95 if (x->size < x->len + n)
96 x->size = x->len + n + 10;
97 x->buf = xrealloc (x->buf, x->size);
98 }
99}
100
101
102/* Append the low N bytes of VAL as an N-byte integer to the
103 expression X, in big-endian order. */
104static void
105append_const (struct agent_expr *x, LONGEST val, int n)
106{
107 int i;
108
109 grow_expr (x, n);
110 for (i = n - 1; i >= 0; i--)
111 {
112 x->buf[x->len + i] = val & 0xff;
113 val >>= 8;
114 }
115 x->len += n;
116}
117
118
119/* Extract an N-byte big-endian unsigned integer from expression X at
120 offset O. */
121static LONGEST
122read_const (struct agent_expr *x, int o, int n)
123{
124 int i;
125 LONGEST accum = 0;
126
127 /* Make sure we're not reading off the end of the expression. */
128 if (o + n > x->len)
129 error (_("GDB bug: ax-general.c (read_const): incomplete constant"));
130
131 for (i = 0; i < n; i++)
132 accum = (accum << 8) | x->buf[o + i];
133
134 return accum;
135}
136
137
138/* Append a simple operator OP to EXPR. */
139void
140ax_simple (struct agent_expr *x, enum agent_op op)
141{
142 grow_expr (x, 1);
143 x->buf[x->len++] = op;
144}
145
c50c785c
JM
146/* Append a pick operator to EXPR. DEPTH is the stack item to pick,
147 with 0 being top of stack. */
148
149void
150ax_pick (struct agent_expr *x, int depth)
151{
152 if (depth < 0 || depth > 255)
153 error (_("GDB bug: ax-general.c (ax_pick): stack depth out of range"));
154 ax_simple (x, aop_pick);
155 append_const (x, 1, depth);
156}
157
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SS
158
159/* Append a sign-extension or zero-extension instruction to EXPR, to
160 extend an N-bit value. */
161static void
162generic_ext (struct agent_expr *x, enum agent_op op, int n)
163{
164 /* N must fit in a byte. */
165 if (n < 0 || n > 255)
166 error (_("GDB bug: ax-general.c (generic_ext): bit count out of range"));
167 /* That had better be enough range. */
168 if (sizeof (LONGEST) * 8 > 255)
c50c785c
JM
169 error (_("GDB bug: ax-general.c (generic_ext): "
170 "opcode has inadequate range"));
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171
172 grow_expr (x, 2);
173 x->buf[x->len++] = op;
174 x->buf[x->len++] = n;
175}
176
177
178/* Append a sign-extension instruction to EXPR, to extend an N-bit value. */
179void
180ax_ext (struct agent_expr *x, int n)
181{
182 generic_ext (x, aop_ext, n);
183}
184
185
186/* Append a zero-extension instruction to EXPR, to extend an N-bit value. */
187void
188ax_zero_ext (struct agent_expr *x, int n)
189{
190 generic_ext (x, aop_zero_ext, n);
191}
192
193
194/* Append a trace_quick instruction to EXPR, to record N bytes. */
195void
196ax_trace_quick (struct agent_expr *x, int n)
197{
198 /* N must fit in a byte. */
199 if (n < 0 || n > 255)
c50c785c
JM
200 error (_("GDB bug: ax-general.c (ax_trace_quick): "
201 "size out of range for trace_quick"));
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SS
202
203 grow_expr (x, 2);
204 x->buf[x->len++] = aop_trace_quick;
205 x->buf[x->len++] = n;
206}
207
208
209/* Append a goto op to EXPR. OP is the actual op (must be aop_goto or
210 aop_if_goto). We assume we don't know the target offset yet,
211 because it's probably a forward branch, so we leave space in EXPR
212 for the target, and return the offset in EXPR of that space, so we
213 can backpatch it once we do know the target offset. Use ax_label
214 to do the backpatching. */
215int
216ax_goto (struct agent_expr *x, enum agent_op op)
217{
218 grow_expr (x, 3);
219 x->buf[x->len + 0] = op;
220 x->buf[x->len + 1] = 0xff;
221 x->buf[x->len + 2] = 0xff;
222 x->len += 3;
223 return x->len - 2;
224}
225
226/* Suppose a given call to ax_goto returns some value PATCH. When you
227 know the offset TARGET that goto should jump to, call
228 ax_label (EXPR, PATCH, TARGET)
229 to patch TARGET into the ax_goto instruction. */
230void
231ax_label (struct agent_expr *x, int patch, int target)
232{
233 /* Make sure the value is in range. Don't accept 0xffff as an
234 offset; that's our magic sentinel value for unpatched branches. */
235 if (target < 0 || target >= 0xffff)
236 error (_("GDB bug: ax-general.c (ax_label): label target out of range"));
237
238 x->buf[patch] = (target >> 8) & 0xff;
239 x->buf[patch + 1] = target & 0xff;
240}
241
242
243/* Assemble code to push a constant on the stack. */
244void
245ax_const_l (struct agent_expr *x, LONGEST l)
246{
247 static enum agent_op ops[]
248 =
249 {aop_const8, aop_const16, aop_const32, aop_const64};
250 int size;
251 int op;
252
253 /* How big is the number? 'op' keeps track of which opcode to use.
254 Notice that we don't really care whether the original number was
255 signed or unsigned; we always reproduce the value exactly, and
256 use the shortest representation. */
257 for (op = 0, size = 8; size < 64; size *= 2, op++)
258 {
cf7f2e2d 259 LONGEST lim = ((LONGEST) 1) << (size - 1);
5796c8dc
SS
260
261 if (-lim <= l && l <= lim - 1)
262 break;
263 }
264
c50c785c 265 /* Emit the right opcode... */
5796c8dc
SS
266 ax_simple (x, ops[op]);
267
268 /* Emit the low SIZE bytes as an unsigned number. We know that
269 sign-extending this will yield l. */
270 append_const (x, l, size / 8);
271
272 /* Now, if it was negative, and not full-sized, sign-extend it. */
273 if (l < 0 && size < 64)
274 ax_ext (x, size);
275}
276
277
278void
279ax_const_d (struct agent_expr *x, LONGEST d)
280{
281 /* FIXME: floating-point support not present yet. */
c50c785c
JM
282 error (_("GDB bug: ax-general.c (ax_const_d): "
283 "floating point not supported yet"));
5796c8dc
SS
284}
285
286
287/* Assemble code to push the value of register number REG on the
288 stack. */
289void
290ax_reg (struct agent_expr *x, int reg)
291{
c50c785c
JM
292 if (reg >= gdbarch_num_regs (x->gdbarch))
293 {
294 /* This is a pseudo-register. */
295 if (!gdbarch_ax_pseudo_register_push_stack_p (x->gdbarch))
296 error (_("'%s' is a pseudo-register; "
297 "GDB cannot yet trace its contents."),
298 user_reg_map_regnum_to_name (x->gdbarch, reg));
299 if (gdbarch_ax_pseudo_register_push_stack (x->gdbarch, x, reg))
300 error (_("Trace '%s' failed."),
301 user_reg_map_regnum_to_name (x->gdbarch, reg));
302 }
303 else
304 {
305 /* Make sure the register number is in range. */
306 if (reg < 0 || reg > 0xffff)
307 error (_("GDB bug: ax-general.c (ax_reg): "
308 "register number out of range"));
309 grow_expr (x, 3);
310 x->buf[x->len] = aop_reg;
311 x->buf[x->len + 1] = (reg >> 8) & 0xff;
312 x->buf[x->len + 2] = (reg) & 0xff;
313 x->len += 3;
314 }
5796c8dc 315}
cf7f2e2d
JM
316
317/* Assemble code to operate on a trace state variable. */
318
319void
320ax_tsv (struct agent_expr *x, enum agent_op op, int num)
321{
322 /* Make sure the tsv number is in range. */
323 if (num < 0 || num > 0xffff)
c50c785c
JM
324 internal_error (__FILE__, __LINE__,
325 _("ax-general.c (ax_tsv): variable "
326 "number is %d, out of range"), num);
cf7f2e2d
JM
327
328 grow_expr (x, 3);
329 x->buf[x->len] = op;
330 x->buf[x->len + 1] = (num >> 8) & 0xff;
331 x->buf[x->len + 2] = (num) & 0xff;
332 x->len += 3;
333}
5796c8dc
SS
334\f
335
336
337/* Functions for disassembling agent expressions, and otherwise
338 debugging the expression compiler. */
339
340struct aop_map aop_map[] =
341{
c50c785c
JM
342 {0, 0, 0, 0, 0}
343#define DEFOP(NAME, SIZE, DATA_SIZE, CONSUMED, PRODUCED, VALUE) \
344 , { # NAME, SIZE, DATA_SIZE, CONSUMED, PRODUCED }
345#include "ax.def"
346#undef DEFOP
5796c8dc
SS
347};
348
349
350/* Disassemble the expression EXPR, writing to F. */
351void
352ax_print (struct ui_file *f, struct agent_expr *x)
353{
354 int i;
355 int is_float = 0;
356
cf7f2e2d
JM
357 fprintf_filtered (f, _("Scope: %s\n"), paddress (x->gdbarch, x->scope));
358 fprintf_filtered (f, _("Reg mask:"));
359 for (i = 0; i < x->reg_mask_len; ++i)
360 fprintf_filtered (f, _(" %02x"), x->reg_mask[i]);
361 fprintf_filtered (f, _("\n"));
362
5796c8dc
SS
363 /* Check the size of the name array against the number of entries in
364 the enum, to catch additions that people didn't sync. */
365 if ((sizeof (aop_map) / sizeof (aop_map[0]))
366 != aop_last)
367 error (_("GDB bug: ax-general.c (ax_print): opcode map out of sync"));
368
369 for (i = 0; i < x->len;)
370 {
371 enum agent_op op = x->buf[i];
372
373 if (op >= (sizeof (aop_map) / sizeof (aop_map[0]))
374 || !aop_map[op].name)
375 {
376 fprintf_filtered (f, _("%3d <bad opcode %02x>\n"), i, op);
377 i++;
378 continue;
379 }
380 if (i + 1 + aop_map[op].op_size > x->len)
381 {
382 fprintf_filtered (f, _("%3d <incomplete opcode %s>\n"),
383 i, aop_map[op].name);
384 break;
385 }
386
387 fprintf_filtered (f, "%3d %s", i, aop_map[op].name);
388 if (aop_map[op].op_size > 0)
389 {
390 fputs_filtered (" ", f);
391
392 print_longest (f, 'd', 0,
393 read_const (x, i + 1, aop_map[op].op_size));
394 }
395 fprintf_filtered (f, "\n");
396 i += 1 + aop_map[op].op_size;
397
398 is_float = (op == aop_float);
399 }
400}
401
cf7f2e2d
JM
402/* Add register REG to the register mask for expression AX. */
403void
404ax_reg_mask (struct agent_expr *ax, int reg)
405{
c50c785c 406 if (reg >= gdbarch_num_regs (ax->gdbarch))
cf7f2e2d 407 {
c50c785c
JM
408 /* This is a pseudo-register. */
409 if (!gdbarch_ax_pseudo_register_collect_p (ax->gdbarch))
410 error (_("'%s' is a pseudo-register; "
411 "GDB cannot yet trace its contents."),
412 user_reg_map_regnum_to_name (ax->gdbarch, reg));
413 if (gdbarch_ax_pseudo_register_collect (ax->gdbarch, ax, reg))
414 error (_("Trace '%s' failed."),
415 user_reg_map_regnum_to_name (ax->gdbarch, reg));
416 }
417 else
418 {
419 int byte = reg / 8;
420
421 /* Grow the bit mask if necessary. */
422 if (byte >= ax->reg_mask_len)
423 {
424 /* It's not appropriate to double here. This isn't a
425 string buffer. */
426 int new_len = byte + 1;
427 unsigned char *new_reg_mask = xrealloc (ax->reg_mask,
428 new_len
429 * sizeof (ax->reg_mask[0]));
430 memset (new_reg_mask + ax->reg_mask_len, 0,
431 (new_len - ax->reg_mask_len) * sizeof (ax->reg_mask[0]));
432 ax->reg_mask_len = new_len;
433 ax->reg_mask = new_reg_mask;
434 }
435
436 ax->reg_mask[byte] |= 1 << (reg % 8);
cf7f2e2d 437 }
cf7f2e2d 438}
5796c8dc 439
cf7f2e2d
JM
440/* Given an agent expression AX, fill in requirements and other descriptive
441 bits. */
5796c8dc 442void
cf7f2e2d 443ax_reqs (struct agent_expr *ax)
5796c8dc
SS
444{
445 int i;
446 int height;
447
5796c8dc
SS
448 /* Jump target table. targets[i] is non-zero iff we have found a
449 jump to offset i. */
450 char *targets = (char *) alloca (ax->len * sizeof (targets[0]));
451
452 /* Instruction boundary table. boundary[i] is non-zero iff our scan
453 has reached an instruction starting at offset i. */
454 char *boundary = (char *) alloca (ax->len * sizeof (boundary[0]));
455
456 /* Stack height record. If either targets[i] or boundary[i] is
457 non-zero, heights[i] is the height the stack should have before
458 executing the bytecode at that point. */
459 int *heights = (int *) alloca (ax->len * sizeof (heights[0]));
460
461 /* Pointer to a description of the present op. */
462 struct aop_map *op;
463
5796c8dc
SS
464 memset (targets, 0, ax->len * sizeof (targets[0]));
465 memset (boundary, 0, ax->len * sizeof (boundary[0]));
466
cf7f2e2d
JM
467 ax->max_height = ax->min_height = height = 0;
468 ax->flaw = agent_flaw_none;
469 ax->max_data_size = 0;
5796c8dc
SS
470
471 for (i = 0; i < ax->len; i += 1 + op->op_size)
472 {
473 if (ax->buf[i] > (sizeof (aop_map) / sizeof (aop_map[0])))
474 {
cf7f2e2d 475 ax->flaw = agent_flaw_bad_instruction;
5796c8dc
SS
476 return;
477 }
478
479 op = &aop_map[ax->buf[i]];
480
481 if (!op->name)
482 {
cf7f2e2d 483 ax->flaw = agent_flaw_bad_instruction;
5796c8dc
SS
484 return;
485 }
486
487 if (i + 1 + op->op_size > ax->len)
488 {
cf7f2e2d 489 ax->flaw = agent_flaw_incomplete_instruction;
5796c8dc
SS
490 return;
491 }
492
493 /* If this instruction is a forward jump target, does the
494 current stack height match the stack height at the jump
495 source? */
496 if (targets[i] && (heights[i] != height))
497 {
cf7f2e2d 498 ax->flaw = agent_flaw_height_mismatch;
5796c8dc
SS
499 return;
500 }
501
502 boundary[i] = 1;
503 heights[i] = height;
504
505 height -= op->consumed;
cf7f2e2d
JM
506 if (height < ax->min_height)
507 ax->min_height = height;
5796c8dc 508 height += op->produced;
cf7f2e2d
JM
509 if (height > ax->max_height)
510 ax->max_height = height;
5796c8dc 511
cf7f2e2d
JM
512 if (op->data_size > ax->max_data_size)
513 ax->max_data_size = op->data_size;
5796c8dc
SS
514
515 /* For jump instructions, check that the target is a valid
516 offset. If it is, record the fact that that location is a
517 jump target, and record the height we expect there. */
518 if (aop_goto == op - aop_map
519 || aop_if_goto == op - aop_map)
520 {
521 int target = read_const (ax, i + 1, 2);
522 if (target < 0 || target >= ax->len)
523 {
cf7f2e2d 524 ax->flaw = agent_flaw_bad_jump;
5796c8dc
SS
525 return;
526 }
527
528 /* Do we have any information about what the stack height
529 should be at the target? */
530 if (targets[target] || boundary[target])
531 {
532 if (heights[target] != height)
533 {
cf7f2e2d 534 ax->flaw = agent_flaw_height_mismatch;
5796c8dc
SS
535 return;
536 }
537 }
538
539 /* Record the target, along with the stack height we expect. */
540 targets[target] = 1;
541 heights[target] = height;
542 }
543
544 /* For unconditional jumps with a successor, check that the
545 successor is a target, and pick up its stack height. */
546 if (aop_goto == op - aop_map
547 && i + 3 < ax->len)
548 {
549 if (!targets[i + 3])
550 {
cf7f2e2d 551 ax->flaw = agent_flaw_hole;
5796c8dc
SS
552 return;
553 }
554
555 height = heights[i + 3];
556 }
557
558 /* For reg instructions, record the register in the bit mask. */
559 if (aop_reg == op - aop_map)
560 {
561 int reg = read_const (ax, i + 1, 2);
5796c8dc 562
cf7f2e2d 563 ax_reg_mask (ax, reg);
5796c8dc
SS
564 }
565 }
566
567 /* Check that all the targets are on boundaries. */
568 for (i = 0; i < ax->len; i++)
569 if (targets[i] && !boundary[i])
570 {
cf7f2e2d 571 ax->flaw = agent_flaw_bad_jump;
5796c8dc
SS
572 return;
573 }
574
cf7f2e2d 575 ax->final_height = height;
5796c8dc 576}