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1bac305b AC |
1 | /* GDB-specific functions for operating on agent expressions. |
2 | ||
4c38e0a4 | 3 | Copyright (C) 1998, 1999, 2000, 2001, 2003, 2007, 2008, 2009, 2010 |
6aba47ca | 4 | Free Software Foundation, Inc. |
c906108c | 5 | |
c5aa993b | 6 | This file is part of GDB. |
c906108c | 7 | |
c5aa993b JM |
8 | This program is free software; you can redistribute it and/or modify |
9 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 10 | the Free Software Foundation; either version 3 of the License, or |
c5aa993b | 11 | (at your option) any later version. |
c906108c | 12 | |
c5aa993b JM |
13 | This program is distributed in the hope that it will be useful, |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
c906108c | 17 | |
c5aa993b | 18 | You should have received a copy of the GNU General Public License |
a9762ec7 | 19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
c906108c | 20 | |
c906108c SS |
21 | #include "defs.h" |
22 | #include "symtab.h" | |
23 | #include "symfile.h" | |
24 | #include "gdbtypes.h" | |
b97aedf3 | 25 | #include "language.h" |
c906108c SS |
26 | #include "value.h" |
27 | #include "expression.h" | |
28 | #include "command.h" | |
29 | #include "gdbcmd.h" | |
30 | #include "frame.h" | |
31 | #include "target.h" | |
32 | #include "ax.h" | |
33 | #include "ax-gdb.h" | |
309367d4 | 34 | #include "gdb_string.h" |
fe898f56 | 35 | #include "block.h" |
7b83296f | 36 | #include "regcache.h" |
029a67e4 | 37 | #include "user-regs.h" |
f7c79c41 | 38 | #include "language.h" |
6c228b9c | 39 | #include "dictionary.h" |
f61e138d | 40 | #include "tracepoint.h" |
c906108c | 41 | |
6426a772 JM |
42 | /* To make sense of this file, you should read doc/agentexpr.texi. |
43 | Then look at the types and enums in ax-gdb.h. For the code itself, | |
44 | look at gen_expr, towards the bottom; that's the main function that | |
45 | looks at the GDB expressions and calls everything else to generate | |
46 | code. | |
c906108c SS |
47 | |
48 | I'm beginning to wonder whether it wouldn't be nicer to internally | |
49 | generate trees, with types, and then spit out the bytecode in | |
50 | linear form afterwards; we could generate fewer `swap', `ext', and | |
51 | `zero_ext' bytecodes that way; it would make good constant folding | |
52 | easier, too. But at the moment, I think we should be willing to | |
53 | pay for the simplicity of this code with less-than-optimal bytecode | |
54 | strings. | |
55 | ||
c5aa993b JM |
56 | Remember, "GBD" stands for "Great Britain, Dammit!" So be careful. */ |
57 | \f | |
c906108c SS |
58 | |
59 | ||
c906108c SS |
60 | /* Prototypes for local functions. */ |
61 | ||
62 | /* There's a standard order to the arguments of these functions: | |
63 | union exp_element ** --- pointer into expression | |
64 | struct agent_expr * --- agent expression buffer to generate code into | |
65 | struct axs_value * --- describes value left on top of stack */ | |
c5aa993b | 66 | |
a14ed312 KB |
67 | static struct value *const_var_ref (struct symbol *var); |
68 | static struct value *const_expr (union exp_element **pc); | |
69 | static struct value *maybe_const_expr (union exp_element **pc); | |
70 | ||
71 | static void gen_traced_pop (struct agent_expr *, struct axs_value *); | |
72 | ||
73 | static void gen_sign_extend (struct agent_expr *, struct type *); | |
74 | static void gen_extend (struct agent_expr *, struct type *); | |
75 | static void gen_fetch (struct agent_expr *, struct type *); | |
76 | static void gen_left_shift (struct agent_expr *, int); | |
77 | ||
78 | ||
f7c79c41 UW |
79 | static void gen_frame_args_address (struct gdbarch *, struct agent_expr *); |
80 | static void gen_frame_locals_address (struct gdbarch *, struct agent_expr *); | |
a14ed312 KB |
81 | static void gen_offset (struct agent_expr *ax, int offset); |
82 | static void gen_sym_offset (struct agent_expr *, struct symbol *); | |
f7c79c41 | 83 | static void gen_var_ref (struct gdbarch *, struct agent_expr *ax, |
a14ed312 KB |
84 | struct axs_value *value, struct symbol *var); |
85 | ||
86 | ||
87 | static void gen_int_literal (struct agent_expr *ax, | |
88 | struct axs_value *value, | |
89 | LONGEST k, struct type *type); | |
90 | ||
91 | ||
92 | static void require_rvalue (struct agent_expr *ax, struct axs_value *value); | |
f7c79c41 UW |
93 | static void gen_usual_unary (struct expression *exp, struct agent_expr *ax, |
94 | struct axs_value *value); | |
a14ed312 KB |
95 | static int type_wider_than (struct type *type1, struct type *type2); |
96 | static struct type *max_type (struct type *type1, struct type *type2); | |
97 | static void gen_conversion (struct agent_expr *ax, | |
98 | struct type *from, struct type *to); | |
99 | static int is_nontrivial_conversion (struct type *from, struct type *to); | |
f7c79c41 UW |
100 | static void gen_usual_arithmetic (struct expression *exp, |
101 | struct agent_expr *ax, | |
a14ed312 KB |
102 | struct axs_value *value1, |
103 | struct axs_value *value2); | |
f7c79c41 UW |
104 | static void gen_integral_promotions (struct expression *exp, |
105 | struct agent_expr *ax, | |
a14ed312 KB |
106 | struct axs_value *value); |
107 | static void gen_cast (struct agent_expr *ax, | |
108 | struct axs_value *value, struct type *type); | |
109 | static void gen_scale (struct agent_expr *ax, | |
110 | enum agent_op op, struct type *type); | |
f7c79c41 UW |
111 | static void gen_ptradd (struct agent_expr *ax, struct axs_value *value, |
112 | struct axs_value *value1, struct axs_value *value2); | |
113 | static void gen_ptrsub (struct agent_expr *ax, struct axs_value *value, | |
114 | struct axs_value *value1, struct axs_value *value2); | |
115 | static void gen_ptrdiff (struct agent_expr *ax, struct axs_value *value, | |
116 | struct axs_value *value1, struct axs_value *value2, | |
117 | struct type *result_type); | |
a14ed312 KB |
118 | static void gen_binop (struct agent_expr *ax, |
119 | struct axs_value *value, | |
120 | struct axs_value *value1, | |
121 | struct axs_value *value2, | |
122 | enum agent_op op, | |
123 | enum agent_op op_unsigned, int may_carry, char *name); | |
f7c79c41 UW |
124 | static void gen_logical_not (struct agent_expr *ax, struct axs_value *value, |
125 | struct type *result_type); | |
a14ed312 KB |
126 | static void gen_complement (struct agent_expr *ax, struct axs_value *value); |
127 | static void gen_deref (struct agent_expr *, struct axs_value *); | |
128 | static void gen_address_of (struct agent_expr *, struct axs_value *); | |
129 | static int find_field (struct type *type, char *name); | |
505e835d | 130 | static void gen_bitfield_ref (struct expression *exp, struct agent_expr *ax, |
a14ed312 KB |
131 | struct axs_value *value, |
132 | struct type *type, int start, int end); | |
505e835d | 133 | static void gen_struct_ref (struct expression *exp, struct agent_expr *ax, |
a14ed312 KB |
134 | struct axs_value *value, |
135 | char *field, | |
136 | char *operator_name, char *operand_name); | |
f7c79c41 | 137 | static void gen_repeat (struct expression *exp, union exp_element **pc, |
a14ed312 | 138 | struct agent_expr *ax, struct axs_value *value); |
f7c79c41 UW |
139 | static void gen_sizeof (struct expression *exp, union exp_element **pc, |
140 | struct agent_expr *ax, struct axs_value *value, | |
141 | struct type *size_type); | |
142 | static void gen_expr (struct expression *exp, union exp_element **pc, | |
a14ed312 | 143 | struct agent_expr *ax, struct axs_value *value); |
f61e138d SS |
144 | static void gen_expr_binop_rest (struct expression *exp, |
145 | enum exp_opcode op, union exp_element **pc, | |
146 | struct agent_expr *ax, | |
147 | struct axs_value *value, | |
148 | struct axs_value *value1, | |
149 | struct axs_value *value2); | |
c5aa993b | 150 | |
a14ed312 | 151 | static void agent_command (char *exp, int from_tty); |
c906108c | 152 | \f |
c5aa993b | 153 | |
c906108c SS |
154 | /* Detecting constant expressions. */ |
155 | ||
156 | /* If the variable reference at *PC is a constant, return its value. | |
157 | Otherwise, return zero. | |
158 | ||
159 | Hey, Wally! How can a variable reference be a constant? | |
160 | ||
161 | Well, Beav, this function really handles the OP_VAR_VALUE operator, | |
162 | not specifically variable references. GDB uses OP_VAR_VALUE to | |
163 | refer to any kind of symbolic reference: function names, enum | |
164 | elements, and goto labels are all handled through the OP_VAR_VALUE | |
165 | operator, even though they're constants. It makes sense given the | |
166 | situation. | |
167 | ||
168 | Gee, Wally, don'cha wonder sometimes if data representations that | |
169 | subvert commonly accepted definitions of terms in favor of heavily | |
170 | context-specific interpretations are really just a tool of the | |
171 | programming hegemony to preserve their power and exclude the | |
172 | proletariat? */ | |
173 | ||
174 | static struct value * | |
fba45db2 | 175 | const_var_ref (struct symbol *var) |
c906108c SS |
176 | { |
177 | struct type *type = SYMBOL_TYPE (var); | |
178 | ||
179 | switch (SYMBOL_CLASS (var)) | |
180 | { | |
181 | case LOC_CONST: | |
182 | return value_from_longest (type, (LONGEST) SYMBOL_VALUE (var)); | |
183 | ||
184 | case LOC_LABEL: | |
4478b372 | 185 | return value_from_pointer (type, (CORE_ADDR) SYMBOL_VALUE_ADDRESS (var)); |
c906108c SS |
186 | |
187 | default: | |
188 | return 0; | |
189 | } | |
190 | } | |
191 | ||
192 | ||
193 | /* If the expression starting at *PC has a constant value, return it. | |
194 | Otherwise, return zero. If we return a value, then *PC will be | |
195 | advanced to the end of it. If we return zero, *PC could be | |
196 | anywhere. */ | |
197 | static struct value * | |
fba45db2 | 198 | const_expr (union exp_element **pc) |
c906108c SS |
199 | { |
200 | enum exp_opcode op = (*pc)->opcode; | |
201 | struct value *v1; | |
202 | ||
203 | switch (op) | |
204 | { | |
205 | case OP_LONG: | |
206 | { | |
207 | struct type *type = (*pc)[1].type; | |
208 | LONGEST k = (*pc)[2].longconst; | |
209 | (*pc) += 4; | |
210 | return value_from_longest (type, k); | |
211 | } | |
212 | ||
213 | case OP_VAR_VALUE: | |
214 | { | |
215 | struct value *v = const_var_ref ((*pc)[2].symbol); | |
216 | (*pc) += 4; | |
217 | return v; | |
218 | } | |
219 | ||
c5aa993b | 220 | /* We could add more operators in here. */ |
c906108c SS |
221 | |
222 | case UNOP_NEG: | |
223 | (*pc)++; | |
224 | v1 = const_expr (pc); | |
225 | if (v1) | |
226 | return value_neg (v1); | |
227 | else | |
228 | return 0; | |
229 | ||
230 | default: | |
231 | return 0; | |
232 | } | |
233 | } | |
234 | ||
235 | ||
236 | /* Like const_expr, but guarantee also that *PC is undisturbed if the | |
237 | expression is not constant. */ | |
238 | static struct value * | |
fba45db2 | 239 | maybe_const_expr (union exp_element **pc) |
c906108c SS |
240 | { |
241 | union exp_element *tentative_pc = *pc; | |
242 | struct value *v = const_expr (&tentative_pc); | |
243 | ||
244 | /* If we got a value, then update the real PC. */ | |
245 | if (v) | |
246 | *pc = tentative_pc; | |
c5aa993b | 247 | |
c906108c SS |
248 | return v; |
249 | } | |
c906108c | 250 | \f |
c5aa993b | 251 | |
c906108c SS |
252 | /* Generating bytecode from GDB expressions: general assumptions */ |
253 | ||
254 | /* Here are a few general assumptions made throughout the code; if you | |
255 | want to make a change that contradicts one of these, then you'd | |
256 | better scan things pretty thoroughly. | |
257 | ||
258 | - We assume that all values occupy one stack element. For example, | |
c5aa993b JM |
259 | sometimes we'll swap to get at the left argument to a binary |
260 | operator. If we decide that void values should occupy no stack | |
261 | elements, or that synthetic arrays (whose size is determined at | |
262 | run time, created by the `@' operator) should occupy two stack | |
263 | elements (address and length), then this will cause trouble. | |
c906108c SS |
264 | |
265 | - We assume the stack elements are infinitely wide, and that we | |
c5aa993b JM |
266 | don't have to worry what happens if the user requests an |
267 | operation that is wider than the actual interpreter's stack. | |
268 | That is, it's up to the interpreter to handle directly all the | |
269 | integer widths the user has access to. (Woe betide the language | |
270 | with bignums!) | |
c906108c SS |
271 | |
272 | - We don't support side effects. Thus, we don't have to worry about | |
c5aa993b | 273 | GCC's generalized lvalues, function calls, etc. |
c906108c SS |
274 | |
275 | - We don't support floating point. Many places where we switch on | |
c5aa993b JM |
276 | some type don't bother to include cases for floating point; there |
277 | may be even more subtle ways this assumption exists. For | |
278 | example, the arguments to % must be integers. | |
c906108c SS |
279 | |
280 | - We assume all subexpressions have a static, unchanging type. If | |
c5aa993b JM |
281 | we tried to support convenience variables, this would be a |
282 | problem. | |
c906108c SS |
283 | |
284 | - All values on the stack should always be fully zero- or | |
c5aa993b JM |
285 | sign-extended. |
286 | ||
287 | (I wasn't sure whether to choose this or its opposite --- that | |
288 | only addresses are assumed extended --- but it turns out that | |
289 | neither convention completely eliminates spurious extend | |
290 | operations (if everything is always extended, then you have to | |
291 | extend after add, because it could overflow; if nothing is | |
292 | extended, then you end up producing extends whenever you change | |
293 | sizes), and this is simpler.) */ | |
c906108c | 294 | \f |
c5aa993b | 295 | |
c906108c SS |
296 | /* Generating bytecode from GDB expressions: the `trace' kludge */ |
297 | ||
298 | /* The compiler in this file is a general-purpose mechanism for | |
299 | translating GDB expressions into bytecode. One ought to be able to | |
300 | find a million and one uses for it. | |
301 | ||
302 | However, at the moment it is HOPELESSLY BRAIN-DAMAGED for the sake | |
303 | of expediency. Let he who is without sin cast the first stone. | |
304 | ||
305 | For the data tracing facility, we need to insert `trace' bytecodes | |
306 | before each data fetch; this records all the memory that the | |
307 | expression touches in the course of evaluation, so that memory will | |
308 | be available when the user later tries to evaluate the expression | |
309 | in GDB. | |
310 | ||
311 | This should be done (I think) in a post-processing pass, that walks | |
312 | an arbitrary agent expression and inserts `trace' operations at the | |
313 | appropriate points. But it's much faster to just hack them | |
314 | directly into the code. And since we're in a crunch, that's what | |
315 | I've done. | |
316 | ||
317 | Setting the flag trace_kludge to non-zero enables the code that | |
318 | emits the trace bytecodes at the appropriate points. */ | |
319 | static int trace_kludge; | |
320 | ||
321 | /* Trace the lvalue on the stack, if it needs it. In either case, pop | |
322 | the value. Useful on the left side of a comma, and at the end of | |
323 | an expression being used for tracing. */ | |
324 | static void | |
fba45db2 | 325 | gen_traced_pop (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
326 | { |
327 | if (trace_kludge) | |
328 | switch (value->kind) | |
329 | { | |
330 | case axs_rvalue: | |
331 | /* We don't trace rvalues, just the lvalues necessary to | |
c5aa993b | 332 | produce them. So just dispose of this value. */ |
c906108c SS |
333 | ax_simple (ax, aop_pop); |
334 | break; | |
335 | ||
336 | case axs_lvalue_memory: | |
337 | { | |
648027cc | 338 | int length = TYPE_LENGTH (check_typedef (value->type)); |
c906108c SS |
339 | |
340 | /* There's no point in trying to use a trace_quick bytecode | |
341 | here, since "trace_quick SIZE pop" is three bytes, whereas | |
342 | "const8 SIZE trace" is also three bytes, does the same | |
343 | thing, and the simplest code which generates that will also | |
344 | work correctly for objects with large sizes. */ | |
345 | ax_const_l (ax, length); | |
346 | ax_simple (ax, aop_trace); | |
347 | } | |
c5aa993b | 348 | break; |
c906108c SS |
349 | |
350 | case axs_lvalue_register: | |
351 | /* We need to mention the register somewhere in the bytecode, | |
352 | so ax_reqs will pick it up and add it to the mask of | |
353 | registers used. */ | |
354 | ax_reg (ax, value->u.reg); | |
355 | ax_simple (ax, aop_pop); | |
356 | break; | |
357 | } | |
358 | else | |
359 | /* If we're not tracing, just pop the value. */ | |
360 | ax_simple (ax, aop_pop); | |
361 | } | |
c5aa993b | 362 | \f |
c906108c SS |
363 | |
364 | ||
c906108c SS |
365 | /* Generating bytecode from GDB expressions: helper functions */ |
366 | ||
367 | /* Assume that the lower bits of the top of the stack is a value of | |
368 | type TYPE, and the upper bits are zero. Sign-extend if necessary. */ | |
369 | static void | |
fba45db2 | 370 | gen_sign_extend (struct agent_expr *ax, struct type *type) |
c906108c SS |
371 | { |
372 | /* Do we need to sign-extend this? */ | |
c5aa993b | 373 | if (!TYPE_UNSIGNED (type)) |
0004e5a2 | 374 | ax_ext (ax, TYPE_LENGTH (type) * TARGET_CHAR_BIT); |
c906108c SS |
375 | } |
376 | ||
377 | ||
378 | /* Assume the lower bits of the top of the stack hold a value of type | |
379 | TYPE, and the upper bits are garbage. Sign-extend or truncate as | |
380 | needed. */ | |
381 | static void | |
fba45db2 | 382 | gen_extend (struct agent_expr *ax, struct type *type) |
c906108c | 383 | { |
0004e5a2 | 384 | int bits = TYPE_LENGTH (type) * TARGET_CHAR_BIT; |
c906108c SS |
385 | /* I just had to. */ |
386 | ((TYPE_UNSIGNED (type) ? ax_zero_ext : ax_ext) (ax, bits)); | |
387 | } | |
388 | ||
389 | ||
390 | /* Assume that the top of the stack contains a value of type "pointer | |
391 | to TYPE"; generate code to fetch its value. Note that TYPE is the | |
392 | target type, not the pointer type. */ | |
393 | static void | |
fba45db2 | 394 | gen_fetch (struct agent_expr *ax, struct type *type) |
c906108c SS |
395 | { |
396 | if (trace_kludge) | |
397 | { | |
398 | /* Record the area of memory we're about to fetch. */ | |
399 | ax_trace_quick (ax, TYPE_LENGTH (type)); | |
400 | } | |
401 | ||
0004e5a2 | 402 | switch (TYPE_CODE (type)) |
c906108c SS |
403 | { |
404 | case TYPE_CODE_PTR: | |
b97aedf3 | 405 | case TYPE_CODE_REF: |
c906108c SS |
406 | case TYPE_CODE_ENUM: |
407 | case TYPE_CODE_INT: | |
408 | case TYPE_CODE_CHAR: | |
409 | /* It's a scalar value, so we know how to dereference it. How | |
410 | many bytes long is it? */ | |
0004e5a2 | 411 | switch (TYPE_LENGTH (type)) |
c906108c | 412 | { |
c5aa993b JM |
413 | case 8 / TARGET_CHAR_BIT: |
414 | ax_simple (ax, aop_ref8); | |
415 | break; | |
416 | case 16 / TARGET_CHAR_BIT: | |
417 | ax_simple (ax, aop_ref16); | |
418 | break; | |
419 | case 32 / TARGET_CHAR_BIT: | |
420 | ax_simple (ax, aop_ref32); | |
421 | break; | |
422 | case 64 / TARGET_CHAR_BIT: | |
423 | ax_simple (ax, aop_ref64); | |
424 | break; | |
c906108c SS |
425 | |
426 | /* Either our caller shouldn't have asked us to dereference | |
427 | that pointer (other code's fault), or we're not | |
428 | implementing something we should be (this code's fault). | |
429 | In any case, it's a bug the user shouldn't see. */ | |
430 | default: | |
8e65ff28 | 431 | internal_error (__FILE__, __LINE__, |
3d263c1d | 432 | _("gen_fetch: strange size")); |
c906108c SS |
433 | } |
434 | ||
435 | gen_sign_extend (ax, type); | |
436 | break; | |
437 | ||
438 | default: | |
439 | /* Either our caller shouldn't have asked us to dereference that | |
c5aa993b JM |
440 | pointer (other code's fault), or we're not implementing |
441 | something we should be (this code's fault). In any case, | |
442 | it's a bug the user shouldn't see. */ | |
8e65ff28 | 443 | internal_error (__FILE__, __LINE__, |
3d263c1d | 444 | _("gen_fetch: bad type code")); |
c906108c SS |
445 | } |
446 | } | |
447 | ||
448 | ||
449 | /* Generate code to left shift the top of the stack by DISTANCE bits, or | |
450 | right shift it by -DISTANCE bits if DISTANCE < 0. This generates | |
451 | unsigned (logical) right shifts. */ | |
452 | static void | |
fba45db2 | 453 | gen_left_shift (struct agent_expr *ax, int distance) |
c906108c SS |
454 | { |
455 | if (distance > 0) | |
456 | { | |
457 | ax_const_l (ax, distance); | |
458 | ax_simple (ax, aop_lsh); | |
459 | } | |
460 | else if (distance < 0) | |
461 | { | |
462 | ax_const_l (ax, -distance); | |
463 | ax_simple (ax, aop_rsh_unsigned); | |
464 | } | |
465 | } | |
c5aa993b | 466 | \f |
c906108c SS |
467 | |
468 | ||
c906108c SS |
469 | /* Generating bytecode from GDB expressions: symbol references */ |
470 | ||
471 | /* Generate code to push the base address of the argument portion of | |
472 | the top stack frame. */ | |
473 | static void | |
f7c79c41 | 474 | gen_frame_args_address (struct gdbarch *gdbarch, struct agent_expr *ax) |
c906108c | 475 | { |
39d4ef09 AC |
476 | int frame_reg; |
477 | LONGEST frame_offset; | |
c906108c | 478 | |
f7c79c41 | 479 | gdbarch_virtual_frame_pointer (gdbarch, |
c7bb205c | 480 | ax->scope, &frame_reg, &frame_offset); |
c5aa993b | 481 | ax_reg (ax, frame_reg); |
c906108c SS |
482 | gen_offset (ax, frame_offset); |
483 | } | |
484 | ||
485 | ||
486 | /* Generate code to push the base address of the locals portion of the | |
487 | top stack frame. */ | |
488 | static void | |
f7c79c41 | 489 | gen_frame_locals_address (struct gdbarch *gdbarch, struct agent_expr *ax) |
c906108c | 490 | { |
39d4ef09 AC |
491 | int frame_reg; |
492 | LONGEST frame_offset; | |
c906108c | 493 | |
f7c79c41 | 494 | gdbarch_virtual_frame_pointer (gdbarch, |
c7bb205c | 495 | ax->scope, &frame_reg, &frame_offset); |
c5aa993b | 496 | ax_reg (ax, frame_reg); |
c906108c SS |
497 | gen_offset (ax, frame_offset); |
498 | } | |
499 | ||
500 | ||
501 | /* Generate code to add OFFSET to the top of the stack. Try to | |
502 | generate short and readable code. We use this for getting to | |
503 | variables on the stack, and structure members. If we were | |
504 | programming in ML, it would be clearer why these are the same | |
505 | thing. */ | |
506 | static void | |
fba45db2 | 507 | gen_offset (struct agent_expr *ax, int offset) |
c906108c SS |
508 | { |
509 | /* It would suffice to simply push the offset and add it, but this | |
510 | makes it easier to read positive and negative offsets in the | |
511 | bytecode. */ | |
512 | if (offset > 0) | |
513 | { | |
514 | ax_const_l (ax, offset); | |
515 | ax_simple (ax, aop_add); | |
516 | } | |
517 | else if (offset < 0) | |
518 | { | |
519 | ax_const_l (ax, -offset); | |
520 | ax_simple (ax, aop_sub); | |
521 | } | |
522 | } | |
523 | ||
524 | ||
525 | /* In many cases, a symbol's value is the offset from some other | |
526 | address (stack frame, base register, etc.) Generate code to add | |
527 | VAR's value to the top of the stack. */ | |
528 | static void | |
fba45db2 | 529 | gen_sym_offset (struct agent_expr *ax, struct symbol *var) |
c906108c SS |
530 | { |
531 | gen_offset (ax, SYMBOL_VALUE (var)); | |
532 | } | |
533 | ||
534 | ||
535 | /* Generate code for a variable reference to AX. The variable is the | |
536 | symbol VAR. Set VALUE to describe the result. */ | |
537 | ||
538 | static void | |
f7c79c41 UW |
539 | gen_var_ref (struct gdbarch *gdbarch, struct agent_expr *ax, |
540 | struct axs_value *value, struct symbol *var) | |
c906108c SS |
541 | { |
542 | /* Dereference any typedefs. */ | |
543 | value->type = check_typedef (SYMBOL_TYPE (var)); | |
544 | ||
545 | /* I'm imitating the code in read_var_value. */ | |
546 | switch (SYMBOL_CLASS (var)) | |
547 | { | |
548 | case LOC_CONST: /* A constant, like an enum value. */ | |
549 | ax_const_l (ax, (LONGEST) SYMBOL_VALUE (var)); | |
550 | value->kind = axs_rvalue; | |
551 | break; | |
552 | ||
553 | case LOC_LABEL: /* A goto label, being used as a value. */ | |
554 | ax_const_l (ax, (LONGEST) SYMBOL_VALUE_ADDRESS (var)); | |
555 | value->kind = axs_rvalue; | |
556 | break; | |
557 | ||
558 | case LOC_CONST_BYTES: | |
8e65ff28 | 559 | internal_error (__FILE__, __LINE__, |
3d263c1d | 560 | _("gen_var_ref: LOC_CONST_BYTES symbols are not supported")); |
c906108c SS |
561 | |
562 | /* Variable at a fixed location in memory. Easy. */ | |
563 | case LOC_STATIC: | |
564 | /* Push the address of the variable. */ | |
565 | ax_const_l (ax, SYMBOL_VALUE_ADDRESS (var)); | |
566 | value->kind = axs_lvalue_memory; | |
567 | break; | |
568 | ||
569 | case LOC_ARG: /* var lives in argument area of frame */ | |
f7c79c41 | 570 | gen_frame_args_address (gdbarch, ax); |
c906108c SS |
571 | gen_sym_offset (ax, var); |
572 | value->kind = axs_lvalue_memory; | |
573 | break; | |
574 | ||
575 | case LOC_REF_ARG: /* As above, but the frame slot really | |
576 | holds the address of the variable. */ | |
f7c79c41 | 577 | gen_frame_args_address (gdbarch, ax); |
c906108c SS |
578 | gen_sym_offset (ax, var); |
579 | /* Don't assume any particular pointer size. */ | |
f7c79c41 | 580 | gen_fetch (ax, builtin_type (gdbarch)->builtin_data_ptr); |
c906108c SS |
581 | value->kind = axs_lvalue_memory; |
582 | break; | |
583 | ||
584 | case LOC_LOCAL: /* var lives in locals area of frame */ | |
f7c79c41 | 585 | gen_frame_locals_address (gdbarch, ax); |
c906108c SS |
586 | gen_sym_offset (ax, var); |
587 | value->kind = axs_lvalue_memory; | |
588 | break; | |
589 | ||
c906108c | 590 | case LOC_TYPEDEF: |
3d263c1d | 591 | error (_("Cannot compute value of typedef `%s'."), |
de5ad195 | 592 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
593 | break; |
594 | ||
595 | case LOC_BLOCK: | |
596 | ax_const_l (ax, BLOCK_START (SYMBOL_BLOCK_VALUE (var))); | |
597 | value->kind = axs_rvalue; | |
598 | break; | |
599 | ||
600 | case LOC_REGISTER: | |
c906108c SS |
601 | /* Don't generate any code at all; in the process of treating |
602 | this as an lvalue or rvalue, the caller will generate the | |
603 | right code. */ | |
604 | value->kind = axs_lvalue_register; | |
768a979c | 605 | value->u.reg = SYMBOL_REGISTER_OPS (var)->register_number (var, gdbarch); |
c906108c SS |
606 | break; |
607 | ||
608 | /* A lot like LOC_REF_ARG, but the pointer lives directly in a | |
2a2d4dc3 AS |
609 | register, not on the stack. Simpler than LOC_REGISTER |
610 | because it's just like any other case where the thing | |
611 | has a real address. */ | |
c906108c | 612 | case LOC_REGPARM_ADDR: |
768a979c | 613 | ax_reg (ax, SYMBOL_REGISTER_OPS (var)->register_number (var, gdbarch)); |
c906108c SS |
614 | value->kind = axs_lvalue_memory; |
615 | break; | |
616 | ||
617 | case LOC_UNRESOLVED: | |
618 | { | |
c5aa993b | 619 | struct minimal_symbol *msym |
3567439c | 620 | = lookup_minimal_symbol (SYMBOL_LINKAGE_NAME (var), NULL, NULL); |
c5aa993b | 621 | if (!msym) |
3d263c1d | 622 | error (_("Couldn't resolve symbol `%s'."), SYMBOL_PRINT_NAME (var)); |
c5aa993b | 623 | |
c906108c SS |
624 | /* Push the address of the variable. */ |
625 | ax_const_l (ax, SYMBOL_VALUE_ADDRESS (msym)); | |
626 | value->kind = axs_lvalue_memory; | |
627 | } | |
c5aa993b | 628 | break; |
c906108c | 629 | |
a55cc764 | 630 | case LOC_COMPUTED: |
a67af2b9 | 631 | /* FIXME: cagney/2004-01-26: It should be possible to |
768a979c | 632 | unconditionally call the SYMBOL_COMPUTED_OPS method when available. |
d3efc286 | 633 | Unfortunately DWARF 2 stores the frame-base (instead of the |
a67af2b9 AC |
634 | function) location in a function's symbol. Oops! For the |
635 | moment enable this when/where applicable. */ | |
505e835d | 636 | SYMBOL_COMPUTED_OPS (var)->tracepoint_var_ref (var, gdbarch, ax, value); |
a55cc764 DJ |
637 | break; |
638 | ||
c906108c | 639 | case LOC_OPTIMIZED_OUT: |
3d263c1d | 640 | error (_("The variable `%s' has been optimized out."), |
de5ad195 | 641 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
642 | break; |
643 | ||
644 | default: | |
3d263c1d | 645 | error (_("Cannot find value of botched symbol `%s'."), |
de5ad195 | 646 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
647 | break; |
648 | } | |
649 | } | |
c5aa993b | 650 | \f |
c906108c SS |
651 | |
652 | ||
c906108c SS |
653 | /* Generating bytecode from GDB expressions: literals */ |
654 | ||
655 | static void | |
fba45db2 KB |
656 | gen_int_literal (struct agent_expr *ax, struct axs_value *value, LONGEST k, |
657 | struct type *type) | |
c906108c SS |
658 | { |
659 | ax_const_l (ax, k); | |
660 | value->kind = axs_rvalue; | |
648027cc | 661 | value->type = check_typedef (type); |
c906108c | 662 | } |
c5aa993b | 663 | \f |
c906108c SS |
664 | |
665 | ||
c906108c SS |
666 | /* Generating bytecode from GDB expressions: unary conversions, casts */ |
667 | ||
668 | /* Take what's on the top of the stack (as described by VALUE), and | |
669 | try to make an rvalue out of it. Signal an error if we can't do | |
670 | that. */ | |
671 | static void | |
fba45db2 | 672 | require_rvalue (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
673 | { |
674 | switch (value->kind) | |
675 | { | |
676 | case axs_rvalue: | |
677 | /* It's already an rvalue. */ | |
678 | break; | |
679 | ||
680 | case axs_lvalue_memory: | |
681 | /* The top of stack is the address of the object. Dereference. */ | |
682 | gen_fetch (ax, value->type); | |
683 | break; | |
684 | ||
685 | case axs_lvalue_register: | |
686 | /* There's nothing on the stack, but value->u.reg is the | |
687 | register number containing the value. | |
688 | ||
c5aa993b JM |
689 | When we add floating-point support, this is going to have to |
690 | change. What about SPARC register pairs, for example? */ | |
c906108c SS |
691 | ax_reg (ax, value->u.reg); |
692 | gen_extend (ax, value->type); | |
693 | break; | |
694 | } | |
695 | ||
696 | value->kind = axs_rvalue; | |
697 | } | |
698 | ||
699 | ||
700 | /* Assume the top of the stack is described by VALUE, and perform the | |
701 | usual unary conversions. This is motivated by ANSI 6.2.2, but of | |
702 | course GDB expressions are not ANSI; they're the mishmash union of | |
703 | a bunch of languages. Rah. | |
704 | ||
705 | NOTE! This function promises to produce an rvalue only when the | |
706 | incoming value is of an appropriate type. In other words, the | |
707 | consumer of the value this function produces may assume the value | |
708 | is an rvalue only after checking its type. | |
709 | ||
710 | The immediate issue is that if the user tries to use a structure or | |
711 | union as an operand of, say, the `+' operator, we don't want to try | |
712 | to convert that structure to an rvalue; require_rvalue will bomb on | |
713 | structs and unions. Rather, we want to simply pass the struct | |
714 | lvalue through unchanged, and let `+' raise an error. */ | |
715 | ||
716 | static void | |
f7c79c41 UW |
717 | gen_usual_unary (struct expression *exp, struct agent_expr *ax, |
718 | struct axs_value *value) | |
c906108c SS |
719 | { |
720 | /* We don't have to generate any code for the usual integral | |
721 | conversions, since values are always represented as full-width on | |
722 | the stack. Should we tweak the type? */ | |
723 | ||
724 | /* Some types require special handling. */ | |
0004e5a2 | 725 | switch (TYPE_CODE (value->type)) |
c906108c SS |
726 | { |
727 | /* Functions get converted to a pointer to the function. */ | |
728 | case TYPE_CODE_FUNC: | |
729 | value->type = lookup_pointer_type (value->type); | |
730 | value->kind = axs_rvalue; /* Should always be true, but just in case. */ | |
731 | break; | |
732 | ||
733 | /* Arrays get converted to a pointer to their first element, and | |
c5aa993b | 734 | are no longer an lvalue. */ |
c906108c SS |
735 | case TYPE_CODE_ARRAY: |
736 | { | |
737 | struct type *elements = TYPE_TARGET_TYPE (value->type); | |
738 | value->type = lookup_pointer_type (elements); | |
739 | value->kind = axs_rvalue; | |
740 | /* We don't need to generate any code; the address of the array | |
741 | is also the address of its first element. */ | |
742 | } | |
c5aa993b | 743 | break; |
c906108c | 744 | |
c5aa993b JM |
745 | /* Don't try to convert structures and unions to rvalues. Let the |
746 | consumer signal an error. */ | |
c906108c SS |
747 | case TYPE_CODE_STRUCT: |
748 | case TYPE_CODE_UNION: | |
749 | return; | |
750 | ||
751 | /* If the value is an enum, call it an integer. */ | |
752 | case TYPE_CODE_ENUM: | |
f7c79c41 | 753 | value->type = builtin_type (exp->gdbarch)->builtin_int; |
c906108c SS |
754 | break; |
755 | } | |
756 | ||
757 | /* If the value is an lvalue, dereference it. */ | |
758 | require_rvalue (ax, value); | |
759 | } | |
760 | ||
761 | ||
762 | /* Return non-zero iff the type TYPE1 is considered "wider" than the | |
763 | type TYPE2, according to the rules described in gen_usual_arithmetic. */ | |
764 | static int | |
fba45db2 | 765 | type_wider_than (struct type *type1, struct type *type2) |
c906108c SS |
766 | { |
767 | return (TYPE_LENGTH (type1) > TYPE_LENGTH (type2) | |
768 | || (TYPE_LENGTH (type1) == TYPE_LENGTH (type2) | |
769 | && TYPE_UNSIGNED (type1) | |
c5aa993b | 770 | && !TYPE_UNSIGNED (type2))); |
c906108c SS |
771 | } |
772 | ||
773 | ||
774 | /* Return the "wider" of the two types TYPE1 and TYPE2. */ | |
775 | static struct type * | |
fba45db2 | 776 | max_type (struct type *type1, struct type *type2) |
c906108c SS |
777 | { |
778 | return type_wider_than (type1, type2) ? type1 : type2; | |
779 | } | |
780 | ||
781 | ||
782 | /* Generate code to convert a scalar value of type FROM to type TO. */ | |
783 | static void | |
fba45db2 | 784 | gen_conversion (struct agent_expr *ax, struct type *from, struct type *to) |
c906108c SS |
785 | { |
786 | /* Perhaps there is a more graceful way to state these rules. */ | |
787 | ||
788 | /* If we're converting to a narrower type, then we need to clear out | |
789 | the upper bits. */ | |
790 | if (TYPE_LENGTH (to) < TYPE_LENGTH (from)) | |
791 | gen_extend (ax, from); | |
792 | ||
793 | /* If the two values have equal width, but different signednesses, | |
794 | then we need to extend. */ | |
795 | else if (TYPE_LENGTH (to) == TYPE_LENGTH (from)) | |
796 | { | |
797 | if (TYPE_UNSIGNED (from) != TYPE_UNSIGNED (to)) | |
798 | gen_extend (ax, to); | |
799 | } | |
800 | ||
801 | /* If we're converting to a wider type, and becoming unsigned, then | |
802 | we need to zero out any possible sign bits. */ | |
803 | else if (TYPE_LENGTH (to) > TYPE_LENGTH (from)) | |
804 | { | |
805 | if (TYPE_UNSIGNED (to)) | |
806 | gen_extend (ax, to); | |
807 | } | |
808 | } | |
809 | ||
810 | ||
811 | /* Return non-zero iff the type FROM will require any bytecodes to be | |
812 | emitted to be converted to the type TO. */ | |
813 | static int | |
fba45db2 | 814 | is_nontrivial_conversion (struct type *from, struct type *to) |
c906108c SS |
815 | { |
816 | struct agent_expr *ax = new_agent_expr (0); | |
817 | int nontrivial; | |
818 | ||
819 | /* Actually generate the code, and see if anything came out. At the | |
820 | moment, it would be trivial to replicate the code in | |
821 | gen_conversion here, but in the future, when we're supporting | |
822 | floating point and the like, it may not be. Doing things this | |
823 | way allows this function to be independent of the logic in | |
824 | gen_conversion. */ | |
825 | gen_conversion (ax, from, to); | |
826 | nontrivial = ax->len > 0; | |
827 | free_agent_expr (ax); | |
828 | return nontrivial; | |
829 | } | |
830 | ||
831 | ||
832 | /* Generate code to perform the "usual arithmetic conversions" (ANSI C | |
833 | 6.2.1.5) for the two operands of an arithmetic operator. This | |
834 | effectively finds a "least upper bound" type for the two arguments, | |
835 | and promotes each argument to that type. *VALUE1 and *VALUE2 | |
836 | describe the values as they are passed in, and as they are left. */ | |
837 | static void | |
f7c79c41 UW |
838 | gen_usual_arithmetic (struct expression *exp, struct agent_expr *ax, |
839 | struct axs_value *value1, struct axs_value *value2) | |
c906108c SS |
840 | { |
841 | /* Do the usual binary conversions. */ | |
842 | if (TYPE_CODE (value1->type) == TYPE_CODE_INT | |
843 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
844 | { | |
845 | /* The ANSI integral promotions seem to work this way: Order the | |
c5aa993b JM |
846 | integer types by size, and then by signedness: an n-bit |
847 | unsigned type is considered "wider" than an n-bit signed | |
848 | type. Promote to the "wider" of the two types, and always | |
849 | promote at least to int. */ | |
f7c79c41 | 850 | struct type *target = max_type (builtin_type (exp->gdbarch)->builtin_int, |
c906108c SS |
851 | max_type (value1->type, value2->type)); |
852 | ||
853 | /* Deal with value2, on the top of the stack. */ | |
854 | gen_conversion (ax, value2->type, target); | |
855 | ||
856 | /* Deal with value1, not on the top of the stack. Don't | |
857 | generate the `swap' instructions if we're not actually going | |
858 | to do anything. */ | |
859 | if (is_nontrivial_conversion (value1->type, target)) | |
860 | { | |
861 | ax_simple (ax, aop_swap); | |
862 | gen_conversion (ax, value1->type, target); | |
863 | ax_simple (ax, aop_swap); | |
864 | } | |
865 | ||
648027cc | 866 | value1->type = value2->type = check_typedef (target); |
c906108c SS |
867 | } |
868 | } | |
869 | ||
870 | ||
871 | /* Generate code to perform the integral promotions (ANSI 6.2.1.1) on | |
872 | the value on the top of the stack, as described by VALUE. Assume | |
873 | the value has integral type. */ | |
874 | static void | |
f7c79c41 UW |
875 | gen_integral_promotions (struct expression *exp, struct agent_expr *ax, |
876 | struct axs_value *value) | |
c906108c | 877 | { |
f7c79c41 UW |
878 | const struct builtin_type *builtin = builtin_type (exp->gdbarch); |
879 | ||
880 | if (!type_wider_than (value->type, builtin->builtin_int)) | |
c906108c | 881 | { |
f7c79c41 UW |
882 | gen_conversion (ax, value->type, builtin->builtin_int); |
883 | value->type = builtin->builtin_int; | |
c906108c | 884 | } |
f7c79c41 | 885 | else if (!type_wider_than (value->type, builtin->builtin_unsigned_int)) |
c906108c | 886 | { |
f7c79c41 UW |
887 | gen_conversion (ax, value->type, builtin->builtin_unsigned_int); |
888 | value->type = builtin->builtin_unsigned_int; | |
c906108c SS |
889 | } |
890 | } | |
891 | ||
892 | ||
893 | /* Generate code for a cast to TYPE. */ | |
894 | static void | |
fba45db2 | 895 | gen_cast (struct agent_expr *ax, struct axs_value *value, struct type *type) |
c906108c SS |
896 | { |
897 | /* GCC does allow casts to yield lvalues, so this should be fixed | |
898 | before merging these changes into the trunk. */ | |
899 | require_rvalue (ax, value); | |
900 | /* Dereference typedefs. */ | |
901 | type = check_typedef (type); | |
902 | ||
0004e5a2 | 903 | switch (TYPE_CODE (type)) |
c906108c SS |
904 | { |
905 | case TYPE_CODE_PTR: | |
b97aedf3 | 906 | case TYPE_CODE_REF: |
c906108c SS |
907 | /* It's implementation-defined, and I'll bet this is what GCC |
908 | does. */ | |
909 | break; | |
910 | ||
911 | case TYPE_CODE_ARRAY: | |
912 | case TYPE_CODE_STRUCT: | |
913 | case TYPE_CODE_UNION: | |
914 | case TYPE_CODE_FUNC: | |
3d263c1d | 915 | error (_("Invalid type cast: intended type must be scalar.")); |
c906108c SS |
916 | |
917 | case TYPE_CODE_ENUM: | |
918 | /* We don't have to worry about the size of the value, because | |
919 | all our integral values are fully sign-extended, and when | |
920 | casting pointers we can do anything we like. Is there any | |
74b35824 JB |
921 | way for us to know what GCC actually does with a cast like |
922 | this? */ | |
c906108c | 923 | break; |
c5aa993b | 924 | |
c906108c SS |
925 | case TYPE_CODE_INT: |
926 | gen_conversion (ax, value->type, type); | |
927 | break; | |
928 | ||
929 | case TYPE_CODE_VOID: | |
930 | /* We could pop the value, and rely on everyone else to check | |
c5aa993b JM |
931 | the type and notice that this value doesn't occupy a stack |
932 | slot. But for now, leave the value on the stack, and | |
933 | preserve the "value == stack element" assumption. */ | |
c906108c SS |
934 | break; |
935 | ||
936 | default: | |
3d263c1d | 937 | error (_("Casts to requested type are not yet implemented.")); |
c906108c SS |
938 | } |
939 | ||
940 | value->type = type; | |
941 | } | |
c5aa993b | 942 | \f |
c906108c SS |
943 | |
944 | ||
c906108c SS |
945 | /* Generating bytecode from GDB expressions: arithmetic */ |
946 | ||
947 | /* Scale the integer on the top of the stack by the size of the target | |
948 | of the pointer type TYPE. */ | |
949 | static void | |
fba45db2 | 950 | gen_scale (struct agent_expr *ax, enum agent_op op, struct type *type) |
c906108c SS |
951 | { |
952 | struct type *element = TYPE_TARGET_TYPE (type); | |
953 | ||
0004e5a2 | 954 | if (TYPE_LENGTH (element) != 1) |
c906108c | 955 | { |
0004e5a2 | 956 | ax_const_l (ax, TYPE_LENGTH (element)); |
c906108c SS |
957 | ax_simple (ax, op); |
958 | } | |
959 | } | |
960 | ||
961 | ||
f7c79c41 | 962 | /* Generate code for pointer arithmetic PTR + INT. */ |
c906108c | 963 | static void |
f7c79c41 UW |
964 | gen_ptradd (struct agent_expr *ax, struct axs_value *value, |
965 | struct axs_value *value1, struct axs_value *value2) | |
c906108c | 966 | { |
b97aedf3 | 967 | gdb_assert (pointer_type (value1->type)); |
f7c79c41 | 968 | gdb_assert (TYPE_CODE (value2->type) == TYPE_CODE_INT); |
c906108c | 969 | |
f7c79c41 UW |
970 | gen_scale (ax, aop_mul, value1->type); |
971 | ax_simple (ax, aop_add); | |
972 | gen_extend (ax, value1->type); /* Catch overflow. */ | |
973 | value->type = value1->type; | |
974 | value->kind = axs_rvalue; | |
975 | } | |
c906108c | 976 | |
c906108c | 977 | |
f7c79c41 UW |
978 | /* Generate code for pointer arithmetic PTR - INT. */ |
979 | static void | |
980 | gen_ptrsub (struct agent_expr *ax, struct axs_value *value, | |
981 | struct axs_value *value1, struct axs_value *value2) | |
982 | { | |
b97aedf3 | 983 | gdb_assert (pointer_type (value1->type)); |
f7c79c41 | 984 | gdb_assert (TYPE_CODE (value2->type) == TYPE_CODE_INT); |
c906108c | 985 | |
f7c79c41 UW |
986 | gen_scale (ax, aop_mul, value1->type); |
987 | ax_simple (ax, aop_sub); | |
988 | gen_extend (ax, value1->type); /* Catch overflow. */ | |
989 | value->type = value1->type; | |
c906108c SS |
990 | value->kind = axs_rvalue; |
991 | } | |
992 | ||
993 | ||
f7c79c41 | 994 | /* Generate code for pointer arithmetic PTR - PTR. */ |
c906108c | 995 | static void |
f7c79c41 UW |
996 | gen_ptrdiff (struct agent_expr *ax, struct axs_value *value, |
997 | struct axs_value *value1, struct axs_value *value2, | |
998 | struct type *result_type) | |
c906108c | 999 | { |
b97aedf3 SS |
1000 | gdb_assert (pointer_type (value1->type)); |
1001 | gdb_assert (pointer_type (value2->type)); | |
c906108c | 1002 | |
f7c79c41 UW |
1003 | if (TYPE_LENGTH (TYPE_TARGET_TYPE (value1->type)) |
1004 | != TYPE_LENGTH (TYPE_TARGET_TYPE (value2->type))) | |
1005 | error (_("\ | |
c906108c | 1006 | First argument of `-' is a pointer, but second argument is neither\n\ |
3d263c1d | 1007 | an integer nor a pointer of the same type.")); |
c906108c | 1008 | |
f7c79c41 UW |
1009 | ax_simple (ax, aop_sub); |
1010 | gen_scale (ax, aop_div_unsigned, value1->type); | |
1011 | value->type = result_type; | |
c906108c SS |
1012 | value->kind = axs_rvalue; |
1013 | } | |
1014 | ||
f7c79c41 | 1015 | |
c906108c SS |
1016 | /* Generate code for a binary operator that doesn't do pointer magic. |
1017 | We set VALUE to describe the result value; we assume VALUE1 and | |
1018 | VALUE2 describe the two operands, and that they've undergone the | |
1019 | usual binary conversions. MAY_CARRY should be non-zero iff the | |
1020 | result needs to be extended. NAME is the English name of the | |
1021 | operator, used in error messages */ | |
1022 | static void | |
fba45db2 KB |
1023 | gen_binop (struct agent_expr *ax, struct axs_value *value, |
1024 | struct axs_value *value1, struct axs_value *value2, enum agent_op op, | |
1025 | enum agent_op op_unsigned, int may_carry, char *name) | |
c906108c SS |
1026 | { |
1027 | /* We only handle INT op INT. */ | |
0004e5a2 DJ |
1028 | if ((TYPE_CODE (value1->type) != TYPE_CODE_INT) |
1029 | || (TYPE_CODE (value2->type) != TYPE_CODE_INT)) | |
3d263c1d | 1030 | error (_("Invalid combination of types in %s."), name); |
c5aa993b | 1031 | |
c906108c SS |
1032 | ax_simple (ax, |
1033 | TYPE_UNSIGNED (value1->type) ? op_unsigned : op); | |
1034 | if (may_carry) | |
c5aa993b | 1035 | gen_extend (ax, value1->type); /* catch overflow */ |
c906108c SS |
1036 | value->type = value1->type; |
1037 | value->kind = axs_rvalue; | |
1038 | } | |
1039 | ||
1040 | ||
1041 | static void | |
f7c79c41 UW |
1042 | gen_logical_not (struct agent_expr *ax, struct axs_value *value, |
1043 | struct type *result_type) | |
c906108c SS |
1044 | { |
1045 | if (TYPE_CODE (value->type) != TYPE_CODE_INT | |
1046 | && TYPE_CODE (value->type) != TYPE_CODE_PTR) | |
3d263c1d | 1047 | error (_("Invalid type of operand to `!'.")); |
c906108c | 1048 | |
c906108c | 1049 | ax_simple (ax, aop_log_not); |
f7c79c41 | 1050 | value->type = result_type; |
c906108c SS |
1051 | } |
1052 | ||
1053 | ||
1054 | static void | |
fba45db2 | 1055 | gen_complement (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1056 | { |
1057 | if (TYPE_CODE (value->type) != TYPE_CODE_INT) | |
3d263c1d | 1058 | error (_("Invalid type of operand to `~'.")); |
c906108c | 1059 | |
c906108c SS |
1060 | ax_simple (ax, aop_bit_not); |
1061 | gen_extend (ax, value->type); | |
1062 | } | |
c5aa993b | 1063 | \f |
c906108c SS |
1064 | |
1065 | ||
c906108c SS |
1066 | /* Generating bytecode from GDB expressions: * & . -> @ sizeof */ |
1067 | ||
1068 | /* Dereference the value on the top of the stack. */ | |
1069 | static void | |
fba45db2 | 1070 | gen_deref (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1071 | { |
1072 | /* The caller should check the type, because several operators use | |
1073 | this, and we don't know what error message to generate. */ | |
b97aedf3 | 1074 | if (!pointer_type (value->type)) |
8e65ff28 | 1075 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1076 | _("gen_deref: expected a pointer")); |
c906108c SS |
1077 | |
1078 | /* We've got an rvalue now, which is a pointer. We want to yield an | |
1079 | lvalue, whose address is exactly that pointer. So we don't | |
1080 | actually emit any code; we just change the type from "Pointer to | |
1081 | T" to "T", and mark the value as an lvalue in memory. Leave it | |
1082 | to the consumer to actually dereference it. */ | |
1083 | value->type = check_typedef (TYPE_TARGET_TYPE (value->type)); | |
0004e5a2 | 1084 | value->kind = ((TYPE_CODE (value->type) == TYPE_CODE_FUNC) |
c906108c SS |
1085 | ? axs_rvalue : axs_lvalue_memory); |
1086 | } | |
1087 | ||
1088 | ||
1089 | /* Produce the address of the lvalue on the top of the stack. */ | |
1090 | static void | |
fba45db2 | 1091 | gen_address_of (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1092 | { |
1093 | /* Special case for taking the address of a function. The ANSI | |
1094 | standard describes this as a special case, too, so this | |
1095 | arrangement is not without motivation. */ | |
0004e5a2 | 1096 | if (TYPE_CODE (value->type) == TYPE_CODE_FUNC) |
c906108c SS |
1097 | /* The value's already an rvalue on the stack, so we just need to |
1098 | change the type. */ | |
1099 | value->type = lookup_pointer_type (value->type); | |
1100 | else | |
1101 | switch (value->kind) | |
1102 | { | |
1103 | case axs_rvalue: | |
3d263c1d | 1104 | error (_("Operand of `&' is an rvalue, which has no address.")); |
c906108c SS |
1105 | |
1106 | case axs_lvalue_register: | |
3d263c1d | 1107 | error (_("Operand of `&' is in a register, and has no address.")); |
c906108c SS |
1108 | |
1109 | case axs_lvalue_memory: | |
1110 | value->kind = axs_rvalue; | |
1111 | value->type = lookup_pointer_type (value->type); | |
1112 | break; | |
1113 | } | |
1114 | } | |
1115 | ||
1116 | ||
1117 | /* A lot of this stuff will have to change to support C++. But we're | |
1118 | not going to deal with that at the moment. */ | |
1119 | ||
1120 | /* Find the field in the structure type TYPE named NAME, and return | |
1121 | its index in TYPE's field array. */ | |
1122 | static int | |
fba45db2 | 1123 | find_field (struct type *type, char *name) |
c906108c SS |
1124 | { |
1125 | int i; | |
1126 | ||
1127 | CHECK_TYPEDEF (type); | |
1128 | ||
1129 | /* Make sure this isn't C++. */ | |
1130 | if (TYPE_N_BASECLASSES (type) != 0) | |
8e65ff28 | 1131 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1132 | _("find_field: derived classes supported")); |
c906108c SS |
1133 | |
1134 | for (i = 0; i < TYPE_NFIELDS (type); i++) | |
1135 | { | |
1136 | char *this_name = TYPE_FIELD_NAME (type, i); | |
1137 | ||
747f3d18 MS |
1138 | if (this_name) |
1139 | { | |
1140 | if (strcmp (name, this_name) == 0) | |
1141 | return i; | |
c906108c | 1142 | |
747f3d18 MS |
1143 | if (this_name[0] == '\0') |
1144 | internal_error (__FILE__, __LINE__, | |
1145 | _("find_field: anonymous unions not supported")); | |
1146 | } | |
c906108c SS |
1147 | } |
1148 | ||
3d263c1d | 1149 | error (_("Couldn't find member named `%s' in struct/union `%s'"), |
7495dfdb | 1150 | name, TYPE_TAG_NAME (type)); |
c906108c SS |
1151 | |
1152 | return 0; | |
1153 | } | |
1154 | ||
1155 | ||
1156 | /* Generate code to push the value of a bitfield of a structure whose | |
1157 | address is on the top of the stack. START and END give the | |
1158 | starting and one-past-ending *bit* numbers of the field within the | |
1159 | structure. */ | |
1160 | static void | |
505e835d UW |
1161 | gen_bitfield_ref (struct expression *exp, struct agent_expr *ax, |
1162 | struct axs_value *value, struct type *type, | |
1163 | int start, int end) | |
c906108c SS |
1164 | { |
1165 | /* Note that ops[i] fetches 8 << i bits. */ | |
1166 | static enum agent_op ops[] | |
c5aa993b JM |
1167 | = |
1168 | {aop_ref8, aop_ref16, aop_ref32, aop_ref64}; | |
c906108c SS |
1169 | static int num_ops = (sizeof (ops) / sizeof (ops[0])); |
1170 | ||
1171 | /* We don't want to touch any byte that the bitfield doesn't | |
1172 | actually occupy; we shouldn't make any accesses we're not | |
1173 | explicitly permitted to. We rely here on the fact that the | |
1174 | bytecode `ref' operators work on unaligned addresses. | |
1175 | ||
1176 | It takes some fancy footwork to get the stack to work the way | |
1177 | we'd like. Say we're retrieving a bitfield that requires three | |
1178 | fetches. Initially, the stack just contains the address: | |
c5aa993b | 1179 | addr |
c906108c | 1180 | For the first fetch, we duplicate the address |
c5aa993b | 1181 | addr addr |
c906108c SS |
1182 | then add the byte offset, do the fetch, and shift and mask as |
1183 | needed, yielding a fragment of the value, properly aligned for | |
1184 | the final bitwise or: | |
c5aa993b | 1185 | addr frag1 |
c906108c | 1186 | then we swap, and repeat the process: |
c5aa993b JM |
1187 | frag1 addr --- address on top |
1188 | frag1 addr addr --- duplicate it | |
1189 | frag1 addr frag2 --- get second fragment | |
1190 | frag1 frag2 addr --- swap again | |
1191 | frag1 frag2 frag3 --- get third fragment | |
c906108c SS |
1192 | Notice that, since the third fragment is the last one, we don't |
1193 | bother duplicating the address this time. Now we have all the | |
1194 | fragments on the stack, and we can simply `or' them together, | |
1195 | yielding the final value of the bitfield. */ | |
1196 | ||
1197 | /* The first and one-after-last bits in the field, but rounded down | |
1198 | and up to byte boundaries. */ | |
1199 | int bound_start = (start / TARGET_CHAR_BIT) * TARGET_CHAR_BIT; | |
c5aa993b JM |
1200 | int bound_end = (((end + TARGET_CHAR_BIT - 1) |
1201 | / TARGET_CHAR_BIT) | |
1202 | * TARGET_CHAR_BIT); | |
c906108c SS |
1203 | |
1204 | /* current bit offset within the structure */ | |
1205 | int offset; | |
1206 | ||
1207 | /* The index in ops of the opcode we're considering. */ | |
1208 | int op; | |
1209 | ||
1210 | /* The number of fragments we generated in the process. Probably | |
1211 | equal to the number of `one' bits in bytesize, but who cares? */ | |
1212 | int fragment_count; | |
1213 | ||
1214 | /* Dereference any typedefs. */ | |
1215 | type = check_typedef (type); | |
1216 | ||
1217 | /* Can we fetch the number of bits requested at all? */ | |
1218 | if ((end - start) > ((1 << num_ops) * 8)) | |
8e65ff28 | 1219 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1220 | _("gen_bitfield_ref: bitfield too wide")); |
c906108c SS |
1221 | |
1222 | /* Note that we know here that we only need to try each opcode once. | |
1223 | That may not be true on machines with weird byte sizes. */ | |
1224 | offset = bound_start; | |
1225 | fragment_count = 0; | |
1226 | for (op = num_ops - 1; op >= 0; op--) | |
1227 | { | |
1228 | /* number of bits that ops[op] would fetch */ | |
1229 | int op_size = 8 << op; | |
1230 | ||
1231 | /* The stack at this point, from bottom to top, contains zero or | |
c5aa993b JM |
1232 | more fragments, then the address. */ |
1233 | ||
c906108c SS |
1234 | /* Does this fetch fit within the bitfield? */ |
1235 | if (offset + op_size <= bound_end) | |
1236 | { | |
1237 | /* Is this the last fragment? */ | |
1238 | int last_frag = (offset + op_size == bound_end); | |
1239 | ||
c5aa993b JM |
1240 | if (!last_frag) |
1241 | ax_simple (ax, aop_dup); /* keep a copy of the address */ | |
1242 | ||
c906108c SS |
1243 | /* Add the offset. */ |
1244 | gen_offset (ax, offset / TARGET_CHAR_BIT); | |
1245 | ||
1246 | if (trace_kludge) | |
1247 | { | |
1248 | /* Record the area of memory we're about to fetch. */ | |
1249 | ax_trace_quick (ax, op_size / TARGET_CHAR_BIT); | |
1250 | } | |
1251 | ||
1252 | /* Perform the fetch. */ | |
1253 | ax_simple (ax, ops[op]); | |
c5aa993b JM |
1254 | |
1255 | /* Shift the bits we have to their proper position. | |
c906108c SS |
1256 | gen_left_shift will generate right shifts when the operand |
1257 | is negative. | |
1258 | ||
c5aa993b JM |
1259 | A big-endian field diagram to ponder: |
1260 | byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 byte 6 byte 7 | |
1261 | +------++------++------++------++------++------++------++------+ | |
1262 | xxxxAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBCCCCCxxxxxxxxxxx | |
1263 | ^ ^ ^ ^ | |
1264 | bit number 16 32 48 53 | |
c906108c SS |
1265 | These are bit numbers as supplied by GDB. Note that the |
1266 | bit numbers run from right to left once you've fetched the | |
1267 | value! | |
1268 | ||
c5aa993b JM |
1269 | A little-endian field diagram to ponder: |
1270 | byte 7 byte 6 byte 5 byte 4 byte 3 byte 2 byte 1 byte 0 | |
1271 | +------++------++------++------++------++------++------++------+ | |
1272 | xxxxxxxxxxxAAAAABBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCCCCCCCCCCCxxxx | |
1273 | ^ ^ ^ ^ ^ | |
1274 | bit number 48 32 16 4 0 | |
1275 | ||
1276 | In both cases, the most significant end is on the left | |
1277 | (i.e. normal numeric writing order), which means that you | |
1278 | don't go crazy thinking about `left' and `right' shifts. | |
1279 | ||
1280 | We don't have to worry about masking yet: | |
1281 | - If they contain garbage off the least significant end, then we | |
1282 | must be looking at the low end of the field, and the right | |
1283 | shift will wipe them out. | |
1284 | - If they contain garbage off the most significant end, then we | |
1285 | must be looking at the most significant end of the word, and | |
1286 | the sign/zero extension will wipe them out. | |
1287 | - If we're in the interior of the word, then there is no garbage | |
1288 | on either end, because the ref operators zero-extend. */ | |
505e835d | 1289 | if (gdbarch_byte_order (exp->gdbarch) == BFD_ENDIAN_BIG) |
c906108c | 1290 | gen_left_shift (ax, end - (offset + op_size)); |
c5aa993b | 1291 | else |
c906108c SS |
1292 | gen_left_shift (ax, offset - start); |
1293 | ||
c5aa993b | 1294 | if (!last_frag) |
c906108c SS |
1295 | /* Bring the copy of the address up to the top. */ |
1296 | ax_simple (ax, aop_swap); | |
1297 | ||
1298 | offset += op_size; | |
1299 | fragment_count++; | |
1300 | } | |
1301 | } | |
1302 | ||
1303 | /* Generate enough bitwise `or' operations to combine all the | |
1304 | fragments we left on the stack. */ | |
1305 | while (fragment_count-- > 1) | |
1306 | ax_simple (ax, aop_bit_or); | |
1307 | ||
1308 | /* Sign- or zero-extend the value as appropriate. */ | |
1309 | ((TYPE_UNSIGNED (type) ? ax_zero_ext : ax_ext) (ax, end - start)); | |
1310 | ||
1311 | /* This is *not* an lvalue. Ugh. */ | |
1312 | value->kind = axs_rvalue; | |
1313 | value->type = type; | |
1314 | } | |
1315 | ||
1316 | ||
1317 | /* Generate code to reference the member named FIELD of a structure or | |
1318 | union. The top of the stack, as described by VALUE, should have | |
1319 | type (pointer to a)* struct/union. OPERATOR_NAME is the name of | |
1320 | the operator being compiled, and OPERAND_NAME is the kind of thing | |
1321 | it operates on; we use them in error messages. */ | |
1322 | static void | |
505e835d UW |
1323 | gen_struct_ref (struct expression *exp, struct agent_expr *ax, |
1324 | struct axs_value *value, char *field, | |
fba45db2 | 1325 | char *operator_name, char *operand_name) |
c906108c SS |
1326 | { |
1327 | struct type *type; | |
1328 | int i; | |
1329 | ||
1330 | /* Follow pointers until we reach a non-pointer. These aren't the C | |
1331 | semantics, but they're what the normal GDB evaluator does, so we | |
1332 | should at least be consistent. */ | |
b97aedf3 | 1333 | while (pointer_type (value->type)) |
c906108c | 1334 | { |
f7c79c41 | 1335 | require_rvalue (ax, value); |
c906108c SS |
1336 | gen_deref (ax, value); |
1337 | } | |
e8860ec2 | 1338 | type = check_typedef (value->type); |
c906108c SS |
1339 | |
1340 | /* This must yield a structure or a union. */ | |
1341 | if (TYPE_CODE (type) != TYPE_CODE_STRUCT | |
1342 | && TYPE_CODE (type) != TYPE_CODE_UNION) | |
3d263c1d | 1343 | error (_("The left operand of `%s' is not a %s."), |
c906108c SS |
1344 | operator_name, operand_name); |
1345 | ||
1346 | /* And it must be in memory; we don't deal with structure rvalues, | |
1347 | or structures living in registers. */ | |
1348 | if (value->kind != axs_lvalue_memory) | |
3d263c1d | 1349 | error (_("Structure does not live in memory.")); |
c906108c SS |
1350 | |
1351 | i = find_field (type, field); | |
c5aa993b | 1352 | |
c906108c SS |
1353 | /* Is this a bitfield? */ |
1354 | if (TYPE_FIELD_PACKED (type, i)) | |
505e835d | 1355 | gen_bitfield_ref (exp, ax, value, TYPE_FIELD_TYPE (type, i), |
c906108c SS |
1356 | TYPE_FIELD_BITPOS (type, i), |
1357 | (TYPE_FIELD_BITPOS (type, i) | |
1358 | + TYPE_FIELD_BITSIZE (type, i))); | |
1359 | else | |
1360 | { | |
1361 | gen_offset (ax, TYPE_FIELD_BITPOS (type, i) / TARGET_CHAR_BIT); | |
1362 | value->kind = axs_lvalue_memory; | |
1363 | value->type = TYPE_FIELD_TYPE (type, i); | |
1364 | } | |
1365 | } | |
1366 | ||
1367 | ||
1368 | /* Generate code for GDB's magical `repeat' operator. | |
1369 | LVALUE @ INT creates an array INT elements long, and whose elements | |
1370 | have the same type as LVALUE, located in memory so that LVALUE is | |
1371 | its first element. For example, argv[0]@argc gives you the array | |
1372 | of command-line arguments. | |
1373 | ||
1374 | Unfortunately, because we have to know the types before we actually | |
1375 | have a value for the expression, we can't implement this perfectly | |
1376 | without changing the type system, having values that occupy two | |
1377 | stack slots, doing weird things with sizeof, etc. So we require | |
1378 | the right operand to be a constant expression. */ | |
1379 | static void | |
f7c79c41 UW |
1380 | gen_repeat (struct expression *exp, union exp_element **pc, |
1381 | struct agent_expr *ax, struct axs_value *value) | |
c906108c SS |
1382 | { |
1383 | struct axs_value value1; | |
1384 | /* We don't want to turn this into an rvalue, so no conversions | |
1385 | here. */ | |
f7c79c41 | 1386 | gen_expr (exp, pc, ax, &value1); |
c906108c | 1387 | if (value1.kind != axs_lvalue_memory) |
3d263c1d | 1388 | error (_("Left operand of `@' must be an object in memory.")); |
c906108c SS |
1389 | |
1390 | /* Evaluate the length; it had better be a constant. */ | |
1391 | { | |
1392 | struct value *v = const_expr (pc); | |
1393 | int length; | |
1394 | ||
c5aa993b | 1395 | if (!v) |
3d263c1d | 1396 | error (_("Right operand of `@' must be a constant, in agent expressions.")); |
04624583 | 1397 | if (TYPE_CODE (value_type (v)) != TYPE_CODE_INT) |
3d263c1d | 1398 | error (_("Right operand of `@' must be an integer.")); |
c906108c SS |
1399 | length = value_as_long (v); |
1400 | if (length <= 0) | |
3d263c1d | 1401 | error (_("Right operand of `@' must be positive.")); |
c906108c SS |
1402 | |
1403 | /* The top of the stack is already the address of the object, so | |
1404 | all we need to do is frob the type of the lvalue. */ | |
1405 | { | |
1406 | /* FIXME-type-allocation: need a way to free this type when we are | |
c5aa993b | 1407 | done with it. */ |
e3506a9f UW |
1408 | struct type *array |
1409 | = lookup_array_range_type (value1.type, 0, length - 1); | |
c906108c SS |
1410 | |
1411 | value->kind = axs_lvalue_memory; | |
1412 | value->type = array; | |
1413 | } | |
1414 | } | |
1415 | } | |
1416 | ||
1417 | ||
1418 | /* Emit code for the `sizeof' operator. | |
1419 | *PC should point at the start of the operand expression; we advance it | |
1420 | to the first instruction after the operand. */ | |
1421 | static void | |
f7c79c41 UW |
1422 | gen_sizeof (struct expression *exp, union exp_element **pc, |
1423 | struct agent_expr *ax, struct axs_value *value, | |
1424 | struct type *size_type) | |
c906108c SS |
1425 | { |
1426 | /* We don't care about the value of the operand expression; we only | |
1427 | care about its type. However, in the current arrangement, the | |
1428 | only way to find an expression's type is to generate code for it. | |
1429 | So we generate code for the operand, and then throw it away, | |
1430 | replacing it with code that simply pushes its size. */ | |
1431 | int start = ax->len; | |
f7c79c41 | 1432 | gen_expr (exp, pc, ax, value); |
c906108c SS |
1433 | |
1434 | /* Throw away the code we just generated. */ | |
1435 | ax->len = start; | |
c5aa993b | 1436 | |
c906108c SS |
1437 | ax_const_l (ax, TYPE_LENGTH (value->type)); |
1438 | value->kind = axs_rvalue; | |
f7c79c41 | 1439 | value->type = size_type; |
c906108c | 1440 | } |
c906108c | 1441 | \f |
c5aa993b | 1442 | |
c906108c SS |
1443 | /* Generating bytecode from GDB expressions: general recursive thingy */ |
1444 | ||
3d263c1d | 1445 | /* XXX: i18n */ |
c906108c SS |
1446 | /* A gen_expr function written by a Gen-X'er guy. |
1447 | Append code for the subexpression of EXPR starting at *POS_P to AX. */ | |
1448 | static void | |
f7c79c41 UW |
1449 | gen_expr (struct expression *exp, union exp_element **pc, |
1450 | struct agent_expr *ax, struct axs_value *value) | |
c906108c SS |
1451 | { |
1452 | /* Used to hold the descriptions of operand expressions. */ | |
09d559e4 | 1453 | struct axs_value value1, value2, value3; |
f61e138d | 1454 | enum exp_opcode op = (*pc)[0].opcode, op2; |
09d559e4 | 1455 | int if1, go1, if2, go2, end; |
c906108c SS |
1456 | |
1457 | /* If we're looking at a constant expression, just push its value. */ | |
1458 | { | |
1459 | struct value *v = maybe_const_expr (pc); | |
c5aa993b | 1460 | |
c906108c SS |
1461 | if (v) |
1462 | { | |
1463 | ax_const_l (ax, value_as_long (v)); | |
1464 | value->kind = axs_rvalue; | |
df407dfe | 1465 | value->type = check_typedef (value_type (v)); |
c906108c SS |
1466 | return; |
1467 | } | |
1468 | } | |
1469 | ||
1470 | /* Otherwise, go ahead and generate code for it. */ | |
1471 | switch (op) | |
1472 | { | |
1473 | /* Binary arithmetic operators. */ | |
1474 | case BINOP_ADD: | |
1475 | case BINOP_SUB: | |
1476 | case BINOP_MUL: | |
1477 | case BINOP_DIV: | |
1478 | case BINOP_REM: | |
1479 | case BINOP_SUBSCRIPT: | |
1480 | case BINOP_BITWISE_AND: | |
1481 | case BINOP_BITWISE_IOR: | |
1482 | case BINOP_BITWISE_XOR: | |
782b2b07 SS |
1483 | case BINOP_EQUAL: |
1484 | case BINOP_NOTEQUAL: | |
1485 | case BINOP_LESS: | |
1486 | case BINOP_GTR: | |
1487 | case BINOP_LEQ: | |
1488 | case BINOP_GEQ: | |
c906108c | 1489 | (*pc)++; |
f7c79c41 UW |
1490 | gen_expr (exp, pc, ax, &value1); |
1491 | gen_usual_unary (exp, ax, &value1); | |
f61e138d SS |
1492 | gen_expr_binop_rest (exp, op, pc, ax, value, &value1, &value2); |
1493 | break; | |
1494 | ||
09d559e4 SS |
1495 | case BINOP_LOGICAL_AND: |
1496 | (*pc)++; | |
1497 | /* Generate the obvious sequence of tests and jumps. */ | |
1498 | gen_expr (exp, pc, ax, &value1); | |
1499 | gen_usual_unary (exp, ax, &value1); | |
1500 | if1 = ax_goto (ax, aop_if_goto); | |
1501 | go1 = ax_goto (ax, aop_goto); | |
1502 | ax_label (ax, if1, ax->len); | |
1503 | gen_expr (exp, pc, ax, &value2); | |
1504 | gen_usual_unary (exp, ax, &value2); | |
1505 | if2 = ax_goto (ax, aop_if_goto); | |
1506 | go2 = ax_goto (ax, aop_goto); | |
1507 | ax_label (ax, if2, ax->len); | |
1508 | ax_const_l (ax, 1); | |
1509 | end = ax_goto (ax, aop_goto); | |
1510 | ax_label (ax, go1, ax->len); | |
1511 | ax_label (ax, go2, ax->len); | |
1512 | ax_const_l (ax, 0); | |
1513 | ax_label (ax, end, ax->len); | |
1514 | value->kind = axs_rvalue; | |
1515 | value->type = language_bool_type (exp->language_defn, exp->gdbarch); | |
1516 | break; | |
1517 | ||
1518 | case BINOP_LOGICAL_OR: | |
1519 | (*pc)++; | |
1520 | /* Generate the obvious sequence of tests and jumps. */ | |
1521 | gen_expr (exp, pc, ax, &value1); | |
1522 | gen_usual_unary (exp, ax, &value1); | |
1523 | if1 = ax_goto (ax, aop_if_goto); | |
1524 | gen_expr (exp, pc, ax, &value2); | |
1525 | gen_usual_unary (exp, ax, &value2); | |
1526 | if2 = ax_goto (ax, aop_if_goto); | |
1527 | ax_const_l (ax, 0); | |
1528 | end = ax_goto (ax, aop_goto); | |
1529 | ax_label (ax, if1, ax->len); | |
1530 | ax_label (ax, if2, ax->len); | |
1531 | ax_const_l (ax, 1); | |
1532 | ax_label (ax, end, ax->len); | |
1533 | value->kind = axs_rvalue; | |
1534 | value->type = language_bool_type (exp->language_defn, exp->gdbarch); | |
1535 | break; | |
1536 | ||
1537 | case TERNOP_COND: | |
1538 | (*pc)++; | |
1539 | gen_expr (exp, pc, ax, &value1); | |
1540 | gen_usual_unary (exp, ax, &value1); | |
1541 | /* For (A ? B : C), it's easiest to generate subexpression | |
1542 | bytecodes in order, but if_goto jumps on true, so we invert | |
1543 | the sense of A. Then we can do B by dropping through, and | |
1544 | jump to do C. */ | |
1545 | gen_logical_not (ax, &value1, | |
1546 | language_bool_type (exp->language_defn, exp->gdbarch)); | |
1547 | if1 = ax_goto (ax, aop_if_goto); | |
1548 | gen_expr (exp, pc, ax, &value2); | |
1549 | gen_usual_unary (exp, ax, &value2); | |
1550 | end = ax_goto (ax, aop_goto); | |
1551 | ax_label (ax, if1, ax->len); | |
1552 | gen_expr (exp, pc, ax, &value3); | |
1553 | gen_usual_unary (exp, ax, &value3); | |
1554 | ax_label (ax, end, ax->len); | |
1555 | /* This is arbitary - what if B and C are incompatible types? */ | |
1556 | value->type = value2.type; | |
1557 | value->kind = value2.kind; | |
1558 | break; | |
1559 | ||
f61e138d SS |
1560 | case BINOP_ASSIGN: |
1561 | (*pc)++; | |
1562 | if ((*pc)[0].opcode == OP_INTERNALVAR) | |
c906108c | 1563 | { |
f61e138d SS |
1564 | char *name = internalvar_name ((*pc)[1].internalvar); |
1565 | struct trace_state_variable *tsv; | |
1566 | (*pc) += 3; | |
1567 | gen_expr (exp, pc, ax, value); | |
1568 | tsv = find_trace_state_variable (name); | |
1569 | if (tsv) | |
f7c79c41 | 1570 | { |
f61e138d SS |
1571 | ax_tsv (ax, aop_setv, tsv->number); |
1572 | if (trace_kludge) | |
1573 | ax_tsv (ax, aop_tracev, tsv->number); | |
f7c79c41 | 1574 | } |
f7c79c41 | 1575 | else |
f61e138d SS |
1576 | error (_("$%s is not a trace state variable, may not assign to it"), name); |
1577 | } | |
1578 | else | |
1579 | error (_("May only assign to trace state variables")); | |
1580 | break; | |
782b2b07 | 1581 | |
f61e138d SS |
1582 | case BINOP_ASSIGN_MODIFY: |
1583 | (*pc)++; | |
1584 | op2 = (*pc)[0].opcode; | |
1585 | (*pc)++; | |
1586 | (*pc)++; | |
1587 | if ((*pc)[0].opcode == OP_INTERNALVAR) | |
1588 | { | |
1589 | char *name = internalvar_name ((*pc)[1].internalvar); | |
1590 | struct trace_state_variable *tsv; | |
1591 | (*pc) += 3; | |
1592 | tsv = find_trace_state_variable (name); | |
1593 | if (tsv) | |
1594 | { | |
1595 | /* The tsv will be the left half of the binary operation. */ | |
1596 | ax_tsv (ax, aop_getv, tsv->number); | |
1597 | if (trace_kludge) | |
1598 | ax_tsv (ax, aop_tracev, tsv->number); | |
1599 | /* Trace state variables are always 64-bit integers. */ | |
1600 | value1.kind = axs_rvalue; | |
1601 | value1.type = builtin_type (exp->gdbarch)->builtin_long_long; | |
1602 | /* Now do right half of expression. */ | |
1603 | gen_expr_binop_rest (exp, op2, pc, ax, value, &value1, &value2); | |
1604 | /* We have a result of the binary op, set the tsv. */ | |
1605 | ax_tsv (ax, aop_setv, tsv->number); | |
1606 | if (trace_kludge) | |
1607 | ax_tsv (ax, aop_tracev, tsv->number); | |
1608 | } | |
1609 | else | |
1610 | error (_("$%s is not a trace state variable, may not assign to it"), name); | |
c906108c | 1611 | } |
f61e138d SS |
1612 | else |
1613 | error (_("May only assign to trace state variables")); | |
c906108c SS |
1614 | break; |
1615 | ||
1616 | /* Note that we need to be a little subtle about generating code | |
c5aa993b JM |
1617 | for comma. In C, we can do some optimizations here because |
1618 | we know the left operand is only being evaluated for effect. | |
1619 | However, if the tracing kludge is in effect, then we always | |
1620 | need to evaluate the left hand side fully, so that all the | |
1621 | variables it mentions get traced. */ | |
c906108c SS |
1622 | case BINOP_COMMA: |
1623 | (*pc)++; | |
f7c79c41 | 1624 | gen_expr (exp, pc, ax, &value1); |
c906108c | 1625 | /* Don't just dispose of the left operand. We might be tracing, |
c5aa993b JM |
1626 | in which case we want to emit code to trace it if it's an |
1627 | lvalue. */ | |
c906108c | 1628 | gen_traced_pop (ax, &value1); |
f7c79c41 | 1629 | gen_expr (exp, pc, ax, value); |
c906108c SS |
1630 | /* It's the consumer's responsibility to trace the right operand. */ |
1631 | break; | |
c5aa993b | 1632 | |
c906108c SS |
1633 | case OP_LONG: /* some integer constant */ |
1634 | { | |
1635 | struct type *type = (*pc)[1].type; | |
1636 | LONGEST k = (*pc)[2].longconst; | |
1637 | (*pc) += 4; | |
1638 | gen_int_literal (ax, value, k, type); | |
1639 | } | |
c5aa993b | 1640 | break; |
c906108c SS |
1641 | |
1642 | case OP_VAR_VALUE: | |
f7c79c41 | 1643 | gen_var_ref (exp->gdbarch, ax, value, (*pc)[2].symbol); |
c906108c SS |
1644 | (*pc) += 4; |
1645 | break; | |
1646 | ||
1647 | case OP_REGISTER: | |
1648 | { | |
67f3407f DJ |
1649 | const char *name = &(*pc)[2].string; |
1650 | int reg; | |
1651 | (*pc) += 4 + BYTES_TO_EXP_ELEM ((*pc)[1].longconst + 1); | |
f7c79c41 | 1652 | reg = user_reg_map_name_to_regnum (exp->gdbarch, name, strlen (name)); |
67f3407f DJ |
1653 | if (reg == -1) |
1654 | internal_error (__FILE__, __LINE__, | |
1655 | _("Register $%s not available"), name); | |
f7c79c41 | 1656 | if (reg >= gdbarch_num_regs (exp->gdbarch)) |
02e4669d JB |
1657 | error (_("'%s' is a pseudo-register; " |
1658 | "GDB cannot yet trace pseudoregister contents."), | |
1659 | name); | |
c906108c SS |
1660 | value->kind = axs_lvalue_register; |
1661 | value->u.reg = reg; | |
f7c79c41 | 1662 | value->type = register_type (exp->gdbarch, reg); |
c906108c | 1663 | } |
c5aa993b | 1664 | break; |
c906108c SS |
1665 | |
1666 | case OP_INTERNALVAR: | |
f61e138d SS |
1667 | { |
1668 | const char *name = internalvar_name ((*pc)[1].internalvar); | |
1669 | struct trace_state_variable *tsv; | |
1670 | (*pc) += 3; | |
1671 | tsv = find_trace_state_variable (name); | |
1672 | if (tsv) | |
1673 | { | |
1674 | ax_tsv (ax, aop_getv, tsv->number); | |
1675 | if (trace_kludge) | |
1676 | ax_tsv (ax, aop_tracev, tsv->number); | |
1677 | /* Trace state variables are always 64-bit integers. */ | |
1678 | value->kind = axs_rvalue; | |
1679 | value->type = builtin_type (exp->gdbarch)->builtin_long_long; | |
1680 | } | |
1681 | else | |
1682 | error (_("$%s is not a trace state variable; GDB agent expressions cannot use convenience variables."), name); | |
1683 | } | |
1684 | break; | |
c906108c | 1685 | |
c5aa993b | 1686 | /* Weirdo operator: see comments for gen_repeat for details. */ |
c906108c SS |
1687 | case BINOP_REPEAT: |
1688 | /* Note that gen_repeat handles its own argument evaluation. */ | |
1689 | (*pc)++; | |
f7c79c41 | 1690 | gen_repeat (exp, pc, ax, value); |
c906108c SS |
1691 | break; |
1692 | ||
1693 | case UNOP_CAST: | |
1694 | { | |
1695 | struct type *type = (*pc)[1].type; | |
1696 | (*pc) += 3; | |
f7c79c41 | 1697 | gen_expr (exp, pc, ax, value); |
c906108c SS |
1698 | gen_cast (ax, value, type); |
1699 | } | |
c5aa993b | 1700 | break; |
c906108c SS |
1701 | |
1702 | case UNOP_MEMVAL: | |
1703 | { | |
1704 | struct type *type = check_typedef ((*pc)[1].type); | |
1705 | (*pc) += 3; | |
f7c79c41 | 1706 | gen_expr (exp, pc, ax, value); |
c906108c SS |
1707 | /* I'm not sure I understand UNOP_MEMVAL entirely. I think |
1708 | it's just a hack for dealing with minsyms; you take some | |
1709 | integer constant, pretend it's the address of an lvalue of | |
1710 | the given type, and dereference it. */ | |
1711 | if (value->kind != axs_rvalue) | |
1712 | /* This would be weird. */ | |
8e65ff28 | 1713 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1714 | _("gen_expr: OP_MEMVAL operand isn't an rvalue???")); |
c906108c SS |
1715 | value->type = type; |
1716 | value->kind = axs_lvalue_memory; | |
1717 | } | |
c5aa993b | 1718 | break; |
c906108c | 1719 | |
36e9969c NS |
1720 | case UNOP_PLUS: |
1721 | (*pc)++; | |
1722 | /* + FOO is equivalent to 0 + FOO, which can be optimized. */ | |
f7c79c41 UW |
1723 | gen_expr (exp, pc, ax, value); |
1724 | gen_usual_unary (exp, ax, value); | |
36e9969c NS |
1725 | break; |
1726 | ||
c906108c SS |
1727 | case UNOP_NEG: |
1728 | (*pc)++; | |
1729 | /* -FOO is equivalent to 0 - FOO. */ | |
22601c15 UW |
1730 | gen_int_literal (ax, &value1, 0, |
1731 | builtin_type (exp->gdbarch)->builtin_int); | |
f7c79c41 UW |
1732 | gen_usual_unary (exp, ax, &value1); /* shouldn't do much */ |
1733 | gen_expr (exp, pc, ax, &value2); | |
1734 | gen_usual_unary (exp, ax, &value2); | |
1735 | gen_usual_arithmetic (exp, ax, &value1, &value2); | |
1736 | gen_binop (ax, value, &value1, &value2, aop_sub, aop_sub, 1, "negation"); | |
c906108c SS |
1737 | break; |
1738 | ||
1739 | case UNOP_LOGICAL_NOT: | |
1740 | (*pc)++; | |
f7c79c41 UW |
1741 | gen_expr (exp, pc, ax, value); |
1742 | gen_usual_unary (exp, ax, value); | |
1743 | gen_logical_not (ax, value, | |
1744 | language_bool_type (exp->language_defn, exp->gdbarch)); | |
c906108c SS |
1745 | break; |
1746 | ||
1747 | case UNOP_COMPLEMENT: | |
1748 | (*pc)++; | |
f7c79c41 UW |
1749 | gen_expr (exp, pc, ax, value); |
1750 | gen_usual_unary (exp, ax, value); | |
1751 | gen_integral_promotions (exp, ax, value); | |
c906108c SS |
1752 | gen_complement (ax, value); |
1753 | break; | |
1754 | ||
1755 | case UNOP_IND: | |
1756 | (*pc)++; | |
f7c79c41 UW |
1757 | gen_expr (exp, pc, ax, value); |
1758 | gen_usual_unary (exp, ax, value); | |
b97aedf3 | 1759 | if (!pointer_type (value->type)) |
3d263c1d | 1760 | error (_("Argument of unary `*' is not a pointer.")); |
c906108c SS |
1761 | gen_deref (ax, value); |
1762 | break; | |
1763 | ||
1764 | case UNOP_ADDR: | |
1765 | (*pc)++; | |
f7c79c41 | 1766 | gen_expr (exp, pc, ax, value); |
c906108c SS |
1767 | gen_address_of (ax, value); |
1768 | break; | |
1769 | ||
1770 | case UNOP_SIZEOF: | |
1771 | (*pc)++; | |
1772 | /* Notice that gen_sizeof handles its own operand, unlike most | |
c5aa993b JM |
1773 | of the other unary operator functions. This is because we |
1774 | have to throw away the code we generate. */ | |
f7c79c41 UW |
1775 | gen_sizeof (exp, pc, ax, value, |
1776 | builtin_type (exp->gdbarch)->builtin_int); | |
c906108c SS |
1777 | break; |
1778 | ||
1779 | case STRUCTOP_STRUCT: | |
1780 | case STRUCTOP_PTR: | |
1781 | { | |
1782 | int length = (*pc)[1].longconst; | |
1783 | char *name = &(*pc)[2].string; | |
1784 | ||
1785 | (*pc) += 4 + BYTES_TO_EXP_ELEM (length + 1); | |
f7c79c41 | 1786 | gen_expr (exp, pc, ax, value); |
c906108c | 1787 | if (op == STRUCTOP_STRUCT) |
505e835d | 1788 | gen_struct_ref (exp, ax, value, name, ".", "structure or union"); |
c906108c | 1789 | else if (op == STRUCTOP_PTR) |
505e835d | 1790 | gen_struct_ref (exp, ax, value, name, "->", |
c906108c SS |
1791 | "pointer to a structure or union"); |
1792 | else | |
1793 | /* If this `if' chain doesn't handle it, then the case list | |
c5aa993b | 1794 | shouldn't mention it, and we shouldn't be here. */ |
8e65ff28 | 1795 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1796 | _("gen_expr: unhandled struct case")); |
c906108c | 1797 | } |
c5aa993b | 1798 | break; |
c906108c | 1799 | |
6c228b9c SS |
1800 | case OP_THIS: |
1801 | { | |
6a0fc12f | 1802 | char *this_name; |
6c228b9c SS |
1803 | struct symbol *func, *sym; |
1804 | struct block *b; | |
1805 | ||
6a0fc12f PA |
1806 | func = block_linkage_function (block_for_pc (ax->scope)); |
1807 | this_name = language_def (SYMBOL_LANGUAGE (func))->la_name_of_this; | |
6c228b9c | 1808 | b = SYMBOL_BLOCK_VALUE (func); |
6c228b9c SS |
1809 | |
1810 | /* Calling lookup_block_symbol is necessary to get the LOC_REGISTER | |
1811 | symbol instead of the LOC_ARG one (if both exist). */ | |
6a0fc12f | 1812 | sym = lookup_block_symbol (b, this_name, NULL, VAR_DOMAIN); |
6c228b9c | 1813 | if (!sym) |
6a0fc12f | 1814 | error (_("no `%s' found"), this_name); |
6c228b9c SS |
1815 | |
1816 | gen_var_ref (exp->gdbarch, ax, value, sym); | |
1817 | (*pc) += 2; | |
1818 | } | |
1819 | break; | |
1820 | ||
c906108c | 1821 | case OP_TYPE: |
3d263c1d | 1822 | error (_("Attempt to use a type name as an expression.")); |
c906108c SS |
1823 | |
1824 | default: | |
3d263c1d | 1825 | error (_("Unsupported operator in expression.")); |
c906108c SS |
1826 | } |
1827 | } | |
f61e138d SS |
1828 | |
1829 | /* This handles the middle-to-right-side of code generation for binary | |
1830 | expressions, which is shared between regular binary operations and | |
1831 | assign-modify (+= and friends) expressions. */ | |
1832 | ||
1833 | static void | |
1834 | gen_expr_binop_rest (struct expression *exp, | |
1835 | enum exp_opcode op, union exp_element **pc, | |
1836 | struct agent_expr *ax, struct axs_value *value, | |
1837 | struct axs_value *value1, struct axs_value *value2) | |
1838 | { | |
1839 | gen_expr (exp, pc, ax, value2); | |
1840 | gen_usual_unary (exp, ax, value2); | |
1841 | gen_usual_arithmetic (exp, ax, value1, value2); | |
1842 | switch (op) | |
1843 | { | |
1844 | case BINOP_ADD: | |
1845 | if (TYPE_CODE (value1->type) == TYPE_CODE_INT | |
b97aedf3 | 1846 | && pointer_type (value2->type)) |
f61e138d SS |
1847 | { |
1848 | /* Swap the values and proceed normally. */ | |
1849 | ax_simple (ax, aop_swap); | |
1850 | gen_ptradd (ax, value, value2, value1); | |
1851 | } | |
b97aedf3 | 1852 | else if (pointer_type (value1->type) |
f61e138d SS |
1853 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) |
1854 | gen_ptradd (ax, value, value1, value2); | |
1855 | else | |
1856 | gen_binop (ax, value, value1, value2, | |
1857 | aop_add, aop_add, 1, "addition"); | |
1858 | break; | |
1859 | case BINOP_SUB: | |
b97aedf3 | 1860 | if (pointer_type (value1->type) |
f61e138d SS |
1861 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) |
1862 | gen_ptrsub (ax,value, value1, value2); | |
b97aedf3 SS |
1863 | else if (pointer_type (value1->type) |
1864 | && pointer_type (value2->type)) | |
f61e138d SS |
1865 | /* FIXME --- result type should be ptrdiff_t */ |
1866 | gen_ptrdiff (ax, value, value1, value2, | |
1867 | builtin_type (exp->gdbarch)->builtin_long); | |
1868 | else | |
1869 | gen_binop (ax, value, value1, value2, | |
1870 | aop_sub, aop_sub, 1, "subtraction"); | |
1871 | break; | |
1872 | case BINOP_MUL: | |
1873 | gen_binop (ax, value, value1, value2, | |
1874 | aop_mul, aop_mul, 1, "multiplication"); | |
1875 | break; | |
1876 | case BINOP_DIV: | |
1877 | gen_binop (ax, value, value1, value2, | |
1878 | aop_div_signed, aop_div_unsigned, 1, "division"); | |
1879 | break; | |
1880 | case BINOP_REM: | |
1881 | gen_binop (ax, value, value1, value2, | |
1882 | aop_rem_signed, aop_rem_unsigned, 1, "remainder"); | |
1883 | break; | |
1884 | case BINOP_SUBSCRIPT: | |
1885 | gen_ptradd (ax, value, value1, value2); | |
b97aedf3 | 1886 | if (!pointer_type (value->type)) |
f61e138d SS |
1887 | error (_("Invalid combination of types in array subscripting.")); |
1888 | gen_deref (ax, value); | |
1889 | break; | |
1890 | case BINOP_BITWISE_AND: | |
1891 | gen_binop (ax, value, value1, value2, | |
1892 | aop_bit_and, aop_bit_and, 0, "bitwise and"); | |
1893 | break; | |
1894 | ||
1895 | case BINOP_BITWISE_IOR: | |
1896 | gen_binop (ax, value, value1, value2, | |
1897 | aop_bit_or, aop_bit_or, 0, "bitwise or"); | |
1898 | break; | |
1899 | ||
1900 | case BINOP_BITWISE_XOR: | |
1901 | gen_binop (ax, value, value1, value2, | |
1902 | aop_bit_xor, aop_bit_xor, 0, "bitwise exclusive-or"); | |
1903 | break; | |
1904 | ||
1905 | case BINOP_EQUAL: | |
1906 | gen_binop (ax, value, value1, value2, | |
1907 | aop_equal, aop_equal, 0, "equal"); | |
1908 | break; | |
1909 | ||
1910 | case BINOP_NOTEQUAL: | |
1911 | gen_binop (ax, value, value1, value2, | |
1912 | aop_equal, aop_equal, 0, "equal"); | |
1913 | gen_logical_not (ax, value, | |
1914 | language_bool_type (exp->language_defn, | |
1915 | exp->gdbarch)); | |
1916 | break; | |
1917 | ||
1918 | case BINOP_LESS: | |
1919 | gen_binop (ax, value, value1, value2, | |
1920 | aop_less_signed, aop_less_unsigned, 0, "less than"); | |
1921 | break; | |
1922 | ||
1923 | case BINOP_GTR: | |
1924 | ax_simple (ax, aop_swap); | |
1925 | gen_binop (ax, value, value1, value2, | |
1926 | aop_less_signed, aop_less_unsigned, 0, "less than"); | |
1927 | break; | |
1928 | ||
1929 | case BINOP_LEQ: | |
1930 | ax_simple (ax, aop_swap); | |
1931 | gen_binop (ax, value, value1, value2, | |
1932 | aop_less_signed, aop_less_unsigned, 0, "less than"); | |
1933 | gen_logical_not (ax, value, | |
1934 | language_bool_type (exp->language_defn, | |
1935 | exp->gdbarch)); | |
1936 | break; | |
1937 | ||
1938 | case BINOP_GEQ: | |
1939 | gen_binop (ax, value, value1, value2, | |
1940 | aop_less_signed, aop_less_unsigned, 0, "less than"); | |
1941 | gen_logical_not (ax, value, | |
1942 | language_bool_type (exp->language_defn, | |
1943 | exp->gdbarch)); | |
1944 | break; | |
1945 | ||
1946 | default: | |
1947 | /* We should only list operators in the outer case statement | |
1948 | that we actually handle in the inner case statement. */ | |
1949 | internal_error (__FILE__, __LINE__, | |
1950 | _("gen_expr: op case sets don't match")); | |
1951 | } | |
1952 | } | |
c906108c | 1953 | \f |
c5aa993b | 1954 | |
0936ad1d SS |
1955 | /* Given a single variable and a scope, generate bytecodes to trace |
1956 | its value. This is for use in situations where we have only a | |
1957 | variable's name, and no parsed expression; for instance, when the | |
1958 | name comes from a list of local variables of a function. */ | |
1959 | ||
1960 | struct agent_expr * | |
1961 | gen_trace_for_var (CORE_ADDR scope, struct symbol *var) | |
1962 | { | |
1963 | struct cleanup *old_chain = 0; | |
1964 | struct agent_expr *ax = new_agent_expr (scope); | |
1965 | struct axs_value value; | |
1966 | ||
1967 | old_chain = make_cleanup_free_agent_expr (ax); | |
1968 | ||
1969 | trace_kludge = 1; | |
1970 | gen_var_ref (NULL, ax, &value, var); | |
1971 | ||
1972 | /* Make sure we record the final object, and get rid of it. */ | |
1973 | gen_traced_pop (ax, &value); | |
1974 | ||
1975 | /* Oh, and terminate. */ | |
1976 | ax_simple (ax, aop_end); | |
1977 | ||
1978 | /* We have successfully built the agent expr, so cancel the cleanup | |
1979 | request. If we add more cleanups that we always want done, this | |
1980 | will have to get more complicated. */ | |
1981 | discard_cleanups (old_chain); | |
1982 | return ax; | |
1983 | } | |
c5aa993b | 1984 | |
c906108c SS |
1985 | /* Generating bytecode from GDB expressions: driver */ |
1986 | ||
c906108c SS |
1987 | /* Given a GDB expression EXPR, return bytecode to trace its value. |
1988 | The result will use the `trace' and `trace_quick' bytecodes to | |
1989 | record the value of all memory touched by the expression. The | |
1990 | caller can then use the ax_reqs function to discover which | |
1991 | registers it relies upon. */ | |
1992 | struct agent_expr * | |
fba45db2 | 1993 | gen_trace_for_expr (CORE_ADDR scope, struct expression *expr) |
c906108c SS |
1994 | { |
1995 | struct cleanup *old_chain = 0; | |
1996 | struct agent_expr *ax = new_agent_expr (scope); | |
1997 | union exp_element *pc; | |
1998 | struct axs_value value; | |
1999 | ||
f23d52e0 | 2000 | old_chain = make_cleanup_free_agent_expr (ax); |
c906108c SS |
2001 | |
2002 | pc = expr->elts; | |
2003 | trace_kludge = 1; | |
f7c79c41 | 2004 | gen_expr (expr, &pc, ax, &value); |
c906108c SS |
2005 | |
2006 | /* Make sure we record the final object, and get rid of it. */ | |
2007 | gen_traced_pop (ax, &value); | |
2008 | ||
2009 | /* Oh, and terminate. */ | |
2010 | ax_simple (ax, aop_end); | |
2011 | ||
2012 | /* We have successfully built the agent expr, so cancel the cleanup | |
2013 | request. If we add more cleanups that we always want done, this | |
2014 | will have to get more complicated. */ | |
2015 | discard_cleanups (old_chain); | |
2016 | return ax; | |
2017 | } | |
c906108c | 2018 | |
782b2b07 SS |
2019 | /* Given a GDB expression EXPR, return a bytecode sequence that will |
2020 | evaluate and return a result. The bytecodes will do a direct | |
2021 | evaluation, using the current data on the target, rather than | |
2022 | recording blocks of memory and registers for later use, as | |
2023 | gen_trace_for_expr does. The generated bytecode sequence leaves | |
2024 | the result of expression evaluation on the top of the stack. */ | |
2025 | ||
2026 | struct agent_expr * | |
2027 | gen_eval_for_expr (CORE_ADDR scope, struct expression *expr) | |
2028 | { | |
2029 | struct cleanup *old_chain = 0; | |
2030 | struct agent_expr *ax = new_agent_expr (scope); | |
2031 | union exp_element *pc; | |
2032 | struct axs_value value; | |
2033 | ||
2034 | old_chain = make_cleanup_free_agent_expr (ax); | |
2035 | ||
2036 | pc = expr->elts; | |
2037 | trace_kludge = 0; | |
2038 | gen_expr (expr, &pc, ax, &value); | |
2039 | ||
2040 | /* Oh, and terminate. */ | |
2041 | ax_simple (ax, aop_end); | |
2042 | ||
2043 | /* We have successfully built the agent expr, so cancel the cleanup | |
2044 | request. If we add more cleanups that we always want done, this | |
2045 | will have to get more complicated. */ | |
2046 | discard_cleanups (old_chain); | |
2047 | return ax; | |
2048 | } | |
2049 | ||
c906108c | 2050 | static void |
fba45db2 | 2051 | agent_command (char *exp, int from_tty) |
c906108c SS |
2052 | { |
2053 | struct cleanup *old_chain = 0; | |
2054 | struct expression *expr; | |
2055 | struct agent_expr *agent; | |
6426a772 | 2056 | struct frame_info *fi = get_current_frame (); /* need current scope */ |
c906108c SS |
2057 | |
2058 | /* We don't deal with overlay debugging at the moment. We need to | |
2059 | think more carefully about this. If you copy this code into | |
2060 | another command, change the error message; the user shouldn't | |
2061 | have to know anything about agent expressions. */ | |
2062 | if (overlay_debugging) | |
3d263c1d | 2063 | error (_("GDB can't do agent expression translation with overlays.")); |
c906108c SS |
2064 | |
2065 | if (exp == 0) | |
3d263c1d | 2066 | error_no_arg (_("expression to translate")); |
c5aa993b | 2067 | |
c906108c | 2068 | expr = parse_expression (exp); |
c13c43fd | 2069 | old_chain = make_cleanup (free_current_contents, &expr); |
bdd78e62 | 2070 | agent = gen_trace_for_expr (get_frame_pc (fi), expr); |
f23d52e0 | 2071 | make_cleanup_free_agent_expr (agent); |
c906108c | 2072 | ax_print (gdb_stdout, agent); |
085dd6e6 JM |
2073 | |
2074 | /* It would be nice to call ax_reqs here to gather some general info | |
2075 | about the expression, and then print out the result. */ | |
c906108c SS |
2076 | |
2077 | do_cleanups (old_chain); | |
2078 | dont_repeat (); | |
2079 | } | |
782b2b07 SS |
2080 | |
2081 | /* Parse the given expression, compile it into an agent expression | |
2082 | that does direct evaluation, and display the resulting | |
2083 | expression. */ | |
2084 | ||
2085 | static void | |
2086 | agent_eval_command (char *exp, int from_tty) | |
2087 | { | |
2088 | struct cleanup *old_chain = 0; | |
2089 | struct expression *expr; | |
2090 | struct agent_expr *agent; | |
2091 | struct frame_info *fi = get_current_frame (); /* need current scope */ | |
2092 | ||
2093 | /* We don't deal with overlay debugging at the moment. We need to | |
2094 | think more carefully about this. If you copy this code into | |
2095 | another command, change the error message; the user shouldn't | |
2096 | have to know anything about agent expressions. */ | |
2097 | if (overlay_debugging) | |
2098 | error (_("GDB can't do agent expression translation with overlays.")); | |
2099 | ||
2100 | if (exp == 0) | |
2101 | error_no_arg (_("expression to translate")); | |
2102 | ||
2103 | expr = parse_expression (exp); | |
2104 | old_chain = make_cleanup (free_current_contents, &expr); | |
2105 | agent = gen_eval_for_expr (get_frame_pc (fi), expr); | |
2106 | make_cleanup_free_agent_expr (agent); | |
2107 | ax_print (gdb_stdout, agent); | |
2108 | ||
2109 | /* It would be nice to call ax_reqs here to gather some general info | |
2110 | about the expression, and then print out the result. */ | |
2111 | ||
2112 | do_cleanups (old_chain); | |
2113 | dont_repeat (); | |
2114 | } | |
c906108c | 2115 | \f |
c5aa993b | 2116 | |
c906108c SS |
2117 | /* Initialization code. */ |
2118 | ||
a14ed312 | 2119 | void _initialize_ax_gdb (void); |
c906108c | 2120 | void |
fba45db2 | 2121 | _initialize_ax_gdb (void) |
c906108c | 2122 | { |
c906108c | 2123 | add_cmd ("agent", class_maintenance, agent_command, |
782b2b07 SS |
2124 | _("Translate an expression into remote agent bytecode for tracing."), |
2125 | &maintenancelist); | |
2126 | ||
2127 | add_cmd ("agent-eval", class_maintenance, agent_eval_command, | |
2128 | _("Translate an expression into remote agent bytecode for evaluation."), | |
c906108c SS |
2129 | &maintenancelist); |
2130 | } |