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1bac305b AC |
1 | /* GDB-specific functions for operating on agent expressions. |
2 | ||
9b254dd1 | 3 | Copyright (C) 1998, 1999, 2000, 2001, 2003, 2007, 2008 |
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" | |
25 | #include "value.h" | |
26 | #include "expression.h" | |
27 | #include "command.h" | |
28 | #include "gdbcmd.h" | |
29 | #include "frame.h" | |
30 | #include "target.h" | |
31 | #include "ax.h" | |
32 | #include "ax-gdb.h" | |
309367d4 | 33 | #include "gdb_string.h" |
fe898f56 | 34 | #include "block.h" |
7b83296f | 35 | #include "regcache.h" |
029a67e4 | 36 | #include "user-regs.h" |
c906108c | 37 | |
6426a772 JM |
38 | /* To make sense of this file, you should read doc/agentexpr.texi. |
39 | Then look at the types and enums in ax-gdb.h. For the code itself, | |
40 | look at gen_expr, towards the bottom; that's the main function that | |
41 | looks at the GDB expressions and calls everything else to generate | |
42 | code. | |
c906108c SS |
43 | |
44 | I'm beginning to wonder whether it wouldn't be nicer to internally | |
45 | generate trees, with types, and then spit out the bytecode in | |
46 | linear form afterwards; we could generate fewer `swap', `ext', and | |
47 | `zero_ext' bytecodes that way; it would make good constant folding | |
48 | easier, too. But at the moment, I think we should be willing to | |
49 | pay for the simplicity of this code with less-than-optimal bytecode | |
50 | strings. | |
51 | ||
c5aa993b JM |
52 | Remember, "GBD" stands for "Great Britain, Dammit!" So be careful. */ |
53 | \f | |
c906108c SS |
54 | |
55 | ||
c906108c SS |
56 | /* Prototypes for local functions. */ |
57 | ||
58 | /* There's a standard order to the arguments of these functions: | |
59 | union exp_element ** --- pointer into expression | |
60 | struct agent_expr * --- agent expression buffer to generate code into | |
61 | struct axs_value * --- describes value left on top of stack */ | |
c5aa993b | 62 | |
a14ed312 KB |
63 | static struct value *const_var_ref (struct symbol *var); |
64 | static struct value *const_expr (union exp_element **pc); | |
65 | static struct value *maybe_const_expr (union exp_element **pc); | |
66 | ||
67 | static void gen_traced_pop (struct agent_expr *, struct axs_value *); | |
68 | ||
69 | static void gen_sign_extend (struct agent_expr *, struct type *); | |
70 | static void gen_extend (struct agent_expr *, struct type *); | |
71 | static void gen_fetch (struct agent_expr *, struct type *); | |
72 | static void gen_left_shift (struct agent_expr *, int); | |
73 | ||
74 | ||
75 | static void gen_frame_args_address (struct agent_expr *); | |
76 | static void gen_frame_locals_address (struct agent_expr *); | |
77 | static void gen_offset (struct agent_expr *ax, int offset); | |
78 | static void gen_sym_offset (struct agent_expr *, struct symbol *); | |
79 | static void gen_var_ref (struct agent_expr *ax, | |
80 | struct axs_value *value, struct symbol *var); | |
81 | ||
82 | ||
83 | static void gen_int_literal (struct agent_expr *ax, | |
84 | struct axs_value *value, | |
85 | LONGEST k, struct type *type); | |
86 | ||
87 | ||
88 | static void require_rvalue (struct agent_expr *ax, struct axs_value *value); | |
89 | static void gen_usual_unary (struct agent_expr *ax, struct axs_value *value); | |
90 | static int type_wider_than (struct type *type1, struct type *type2); | |
91 | static struct type *max_type (struct type *type1, struct type *type2); | |
92 | static void gen_conversion (struct agent_expr *ax, | |
93 | struct type *from, struct type *to); | |
94 | static int is_nontrivial_conversion (struct type *from, struct type *to); | |
95 | static void gen_usual_arithmetic (struct agent_expr *ax, | |
96 | struct axs_value *value1, | |
97 | struct axs_value *value2); | |
98 | static void gen_integral_promotions (struct agent_expr *ax, | |
99 | struct axs_value *value); | |
100 | static void gen_cast (struct agent_expr *ax, | |
101 | struct axs_value *value, struct type *type); | |
102 | static void gen_scale (struct agent_expr *ax, | |
103 | enum agent_op op, struct type *type); | |
104 | static void gen_add (struct agent_expr *ax, | |
105 | struct axs_value *value, | |
106 | struct axs_value *value1, | |
107 | struct axs_value *value2, char *name); | |
108 | static void gen_sub (struct agent_expr *ax, | |
109 | struct axs_value *value, | |
110 | struct axs_value *value1, struct axs_value *value2); | |
111 | static void gen_binop (struct agent_expr *ax, | |
112 | struct axs_value *value, | |
113 | struct axs_value *value1, | |
114 | struct axs_value *value2, | |
115 | enum agent_op op, | |
116 | enum agent_op op_unsigned, int may_carry, char *name); | |
117 | static void gen_logical_not (struct agent_expr *ax, struct axs_value *value); | |
118 | static void gen_complement (struct agent_expr *ax, struct axs_value *value); | |
119 | static void gen_deref (struct agent_expr *, struct axs_value *); | |
120 | static void gen_address_of (struct agent_expr *, struct axs_value *); | |
121 | static int find_field (struct type *type, char *name); | |
122 | static void gen_bitfield_ref (struct agent_expr *ax, | |
123 | struct axs_value *value, | |
124 | struct type *type, int start, int end); | |
125 | static void gen_struct_ref (struct agent_expr *ax, | |
126 | struct axs_value *value, | |
127 | char *field, | |
128 | char *operator_name, char *operand_name); | |
129 | static void gen_repeat (union exp_element **pc, | |
130 | struct agent_expr *ax, struct axs_value *value); | |
131 | static void gen_sizeof (union exp_element **pc, | |
132 | struct agent_expr *ax, struct axs_value *value); | |
133 | static void gen_expr (union exp_element **pc, | |
134 | struct agent_expr *ax, struct axs_value *value); | |
c5aa993b | 135 | |
a14ed312 | 136 | static void agent_command (char *exp, int from_tty); |
c906108c | 137 | \f |
c5aa993b | 138 | |
c906108c SS |
139 | /* Detecting constant expressions. */ |
140 | ||
141 | /* If the variable reference at *PC is a constant, return its value. | |
142 | Otherwise, return zero. | |
143 | ||
144 | Hey, Wally! How can a variable reference be a constant? | |
145 | ||
146 | Well, Beav, this function really handles the OP_VAR_VALUE operator, | |
147 | not specifically variable references. GDB uses OP_VAR_VALUE to | |
148 | refer to any kind of symbolic reference: function names, enum | |
149 | elements, and goto labels are all handled through the OP_VAR_VALUE | |
150 | operator, even though they're constants. It makes sense given the | |
151 | situation. | |
152 | ||
153 | Gee, Wally, don'cha wonder sometimes if data representations that | |
154 | subvert commonly accepted definitions of terms in favor of heavily | |
155 | context-specific interpretations are really just a tool of the | |
156 | programming hegemony to preserve their power and exclude the | |
157 | proletariat? */ | |
158 | ||
159 | static struct value * | |
fba45db2 | 160 | const_var_ref (struct symbol *var) |
c906108c SS |
161 | { |
162 | struct type *type = SYMBOL_TYPE (var); | |
163 | ||
164 | switch (SYMBOL_CLASS (var)) | |
165 | { | |
166 | case LOC_CONST: | |
167 | return value_from_longest (type, (LONGEST) SYMBOL_VALUE (var)); | |
168 | ||
169 | case LOC_LABEL: | |
4478b372 | 170 | return value_from_pointer (type, (CORE_ADDR) SYMBOL_VALUE_ADDRESS (var)); |
c906108c SS |
171 | |
172 | default: | |
173 | return 0; | |
174 | } | |
175 | } | |
176 | ||
177 | ||
178 | /* If the expression starting at *PC has a constant value, return it. | |
179 | Otherwise, return zero. If we return a value, then *PC will be | |
180 | advanced to the end of it. If we return zero, *PC could be | |
181 | anywhere. */ | |
182 | static struct value * | |
fba45db2 | 183 | const_expr (union exp_element **pc) |
c906108c SS |
184 | { |
185 | enum exp_opcode op = (*pc)->opcode; | |
186 | struct value *v1; | |
187 | ||
188 | switch (op) | |
189 | { | |
190 | case OP_LONG: | |
191 | { | |
192 | struct type *type = (*pc)[1].type; | |
193 | LONGEST k = (*pc)[2].longconst; | |
194 | (*pc) += 4; | |
195 | return value_from_longest (type, k); | |
196 | } | |
197 | ||
198 | case OP_VAR_VALUE: | |
199 | { | |
200 | struct value *v = const_var_ref ((*pc)[2].symbol); | |
201 | (*pc) += 4; | |
202 | return v; | |
203 | } | |
204 | ||
c5aa993b | 205 | /* We could add more operators in here. */ |
c906108c SS |
206 | |
207 | case UNOP_NEG: | |
208 | (*pc)++; | |
209 | v1 = const_expr (pc); | |
210 | if (v1) | |
211 | return value_neg (v1); | |
212 | else | |
213 | return 0; | |
214 | ||
215 | default: | |
216 | return 0; | |
217 | } | |
218 | } | |
219 | ||
220 | ||
221 | /* Like const_expr, but guarantee also that *PC is undisturbed if the | |
222 | expression is not constant. */ | |
223 | static struct value * | |
fba45db2 | 224 | maybe_const_expr (union exp_element **pc) |
c906108c SS |
225 | { |
226 | union exp_element *tentative_pc = *pc; | |
227 | struct value *v = const_expr (&tentative_pc); | |
228 | ||
229 | /* If we got a value, then update the real PC. */ | |
230 | if (v) | |
231 | *pc = tentative_pc; | |
c5aa993b | 232 | |
c906108c SS |
233 | return v; |
234 | } | |
c906108c | 235 | \f |
c5aa993b | 236 | |
c906108c SS |
237 | /* Generating bytecode from GDB expressions: general assumptions */ |
238 | ||
239 | /* Here are a few general assumptions made throughout the code; if you | |
240 | want to make a change that contradicts one of these, then you'd | |
241 | better scan things pretty thoroughly. | |
242 | ||
243 | - We assume that all values occupy one stack element. For example, | |
c5aa993b JM |
244 | sometimes we'll swap to get at the left argument to a binary |
245 | operator. If we decide that void values should occupy no stack | |
246 | elements, or that synthetic arrays (whose size is determined at | |
247 | run time, created by the `@' operator) should occupy two stack | |
248 | elements (address and length), then this will cause trouble. | |
c906108c SS |
249 | |
250 | - We assume the stack elements are infinitely wide, and that we | |
c5aa993b JM |
251 | don't have to worry what happens if the user requests an |
252 | operation that is wider than the actual interpreter's stack. | |
253 | That is, it's up to the interpreter to handle directly all the | |
254 | integer widths the user has access to. (Woe betide the language | |
255 | with bignums!) | |
c906108c SS |
256 | |
257 | - We don't support side effects. Thus, we don't have to worry about | |
c5aa993b | 258 | GCC's generalized lvalues, function calls, etc. |
c906108c SS |
259 | |
260 | - We don't support floating point. Many places where we switch on | |
c5aa993b JM |
261 | some type don't bother to include cases for floating point; there |
262 | may be even more subtle ways this assumption exists. For | |
263 | example, the arguments to % must be integers. | |
c906108c SS |
264 | |
265 | - We assume all subexpressions have a static, unchanging type. If | |
c5aa993b JM |
266 | we tried to support convenience variables, this would be a |
267 | problem. | |
c906108c SS |
268 | |
269 | - All values on the stack should always be fully zero- or | |
c5aa993b JM |
270 | sign-extended. |
271 | ||
272 | (I wasn't sure whether to choose this or its opposite --- that | |
273 | only addresses are assumed extended --- but it turns out that | |
274 | neither convention completely eliminates spurious extend | |
275 | operations (if everything is always extended, then you have to | |
276 | extend after add, because it could overflow; if nothing is | |
277 | extended, then you end up producing extends whenever you change | |
278 | sizes), and this is simpler.) */ | |
c906108c | 279 | \f |
c5aa993b | 280 | |
c906108c SS |
281 | /* Generating bytecode from GDB expressions: the `trace' kludge */ |
282 | ||
283 | /* The compiler in this file is a general-purpose mechanism for | |
284 | translating GDB expressions into bytecode. One ought to be able to | |
285 | find a million and one uses for it. | |
286 | ||
287 | However, at the moment it is HOPELESSLY BRAIN-DAMAGED for the sake | |
288 | of expediency. Let he who is without sin cast the first stone. | |
289 | ||
290 | For the data tracing facility, we need to insert `trace' bytecodes | |
291 | before each data fetch; this records all the memory that the | |
292 | expression touches in the course of evaluation, so that memory will | |
293 | be available when the user later tries to evaluate the expression | |
294 | in GDB. | |
295 | ||
296 | This should be done (I think) in a post-processing pass, that walks | |
297 | an arbitrary agent expression and inserts `trace' operations at the | |
298 | appropriate points. But it's much faster to just hack them | |
299 | directly into the code. And since we're in a crunch, that's what | |
300 | I've done. | |
301 | ||
302 | Setting the flag trace_kludge to non-zero enables the code that | |
303 | emits the trace bytecodes at the appropriate points. */ | |
304 | static int trace_kludge; | |
305 | ||
306 | /* Trace the lvalue on the stack, if it needs it. In either case, pop | |
307 | the value. Useful on the left side of a comma, and at the end of | |
308 | an expression being used for tracing. */ | |
309 | static void | |
fba45db2 | 310 | gen_traced_pop (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
311 | { |
312 | if (trace_kludge) | |
313 | switch (value->kind) | |
314 | { | |
315 | case axs_rvalue: | |
316 | /* We don't trace rvalues, just the lvalues necessary to | |
c5aa993b | 317 | produce them. So just dispose of this value. */ |
c906108c SS |
318 | ax_simple (ax, aop_pop); |
319 | break; | |
320 | ||
321 | case axs_lvalue_memory: | |
322 | { | |
648027cc | 323 | int length = TYPE_LENGTH (check_typedef (value->type)); |
c906108c SS |
324 | |
325 | /* There's no point in trying to use a trace_quick bytecode | |
326 | here, since "trace_quick SIZE pop" is three bytes, whereas | |
327 | "const8 SIZE trace" is also three bytes, does the same | |
328 | thing, and the simplest code which generates that will also | |
329 | work correctly for objects with large sizes. */ | |
330 | ax_const_l (ax, length); | |
331 | ax_simple (ax, aop_trace); | |
332 | } | |
c5aa993b | 333 | break; |
c906108c SS |
334 | |
335 | case axs_lvalue_register: | |
336 | /* We need to mention the register somewhere in the bytecode, | |
337 | so ax_reqs will pick it up and add it to the mask of | |
338 | registers used. */ | |
339 | ax_reg (ax, value->u.reg); | |
340 | ax_simple (ax, aop_pop); | |
341 | break; | |
342 | } | |
343 | else | |
344 | /* If we're not tracing, just pop the value. */ | |
345 | ax_simple (ax, aop_pop); | |
346 | } | |
c5aa993b | 347 | \f |
c906108c SS |
348 | |
349 | ||
c906108c SS |
350 | /* Generating bytecode from GDB expressions: helper functions */ |
351 | ||
352 | /* Assume that the lower bits of the top of the stack is a value of | |
353 | type TYPE, and the upper bits are zero. Sign-extend if necessary. */ | |
354 | static void | |
fba45db2 | 355 | gen_sign_extend (struct agent_expr *ax, struct type *type) |
c906108c SS |
356 | { |
357 | /* Do we need to sign-extend this? */ | |
c5aa993b | 358 | if (!TYPE_UNSIGNED (type)) |
0004e5a2 | 359 | ax_ext (ax, TYPE_LENGTH (type) * TARGET_CHAR_BIT); |
c906108c SS |
360 | } |
361 | ||
362 | ||
363 | /* Assume the lower bits of the top of the stack hold a value of type | |
364 | TYPE, and the upper bits are garbage. Sign-extend or truncate as | |
365 | needed. */ | |
366 | static void | |
fba45db2 | 367 | gen_extend (struct agent_expr *ax, struct type *type) |
c906108c | 368 | { |
0004e5a2 | 369 | int bits = TYPE_LENGTH (type) * TARGET_CHAR_BIT; |
c906108c SS |
370 | /* I just had to. */ |
371 | ((TYPE_UNSIGNED (type) ? ax_zero_ext : ax_ext) (ax, bits)); | |
372 | } | |
373 | ||
374 | ||
375 | /* Assume that the top of the stack contains a value of type "pointer | |
376 | to TYPE"; generate code to fetch its value. Note that TYPE is the | |
377 | target type, not the pointer type. */ | |
378 | static void | |
fba45db2 | 379 | gen_fetch (struct agent_expr *ax, struct type *type) |
c906108c SS |
380 | { |
381 | if (trace_kludge) | |
382 | { | |
383 | /* Record the area of memory we're about to fetch. */ | |
384 | ax_trace_quick (ax, TYPE_LENGTH (type)); | |
385 | } | |
386 | ||
0004e5a2 | 387 | switch (TYPE_CODE (type)) |
c906108c SS |
388 | { |
389 | case TYPE_CODE_PTR: | |
390 | case TYPE_CODE_ENUM: | |
391 | case TYPE_CODE_INT: | |
392 | case TYPE_CODE_CHAR: | |
393 | /* It's a scalar value, so we know how to dereference it. How | |
394 | many bytes long is it? */ | |
0004e5a2 | 395 | switch (TYPE_LENGTH (type)) |
c906108c | 396 | { |
c5aa993b JM |
397 | case 8 / TARGET_CHAR_BIT: |
398 | ax_simple (ax, aop_ref8); | |
399 | break; | |
400 | case 16 / TARGET_CHAR_BIT: | |
401 | ax_simple (ax, aop_ref16); | |
402 | break; | |
403 | case 32 / TARGET_CHAR_BIT: | |
404 | ax_simple (ax, aop_ref32); | |
405 | break; | |
406 | case 64 / TARGET_CHAR_BIT: | |
407 | ax_simple (ax, aop_ref64); | |
408 | break; | |
c906108c SS |
409 | |
410 | /* Either our caller shouldn't have asked us to dereference | |
411 | that pointer (other code's fault), or we're not | |
412 | implementing something we should be (this code's fault). | |
413 | In any case, it's a bug the user shouldn't see. */ | |
414 | default: | |
8e65ff28 | 415 | internal_error (__FILE__, __LINE__, |
3d263c1d | 416 | _("gen_fetch: strange size")); |
c906108c SS |
417 | } |
418 | ||
419 | gen_sign_extend (ax, type); | |
420 | break; | |
421 | ||
422 | default: | |
423 | /* Either our caller shouldn't have asked us to dereference that | |
c5aa993b JM |
424 | pointer (other code's fault), or we're not implementing |
425 | something we should be (this code's fault). In any case, | |
426 | it's a bug the user shouldn't see. */ | |
8e65ff28 | 427 | internal_error (__FILE__, __LINE__, |
3d263c1d | 428 | _("gen_fetch: bad type code")); |
c906108c SS |
429 | } |
430 | } | |
431 | ||
432 | ||
433 | /* Generate code to left shift the top of the stack by DISTANCE bits, or | |
434 | right shift it by -DISTANCE bits if DISTANCE < 0. This generates | |
435 | unsigned (logical) right shifts. */ | |
436 | static void | |
fba45db2 | 437 | gen_left_shift (struct agent_expr *ax, int distance) |
c906108c SS |
438 | { |
439 | if (distance > 0) | |
440 | { | |
441 | ax_const_l (ax, distance); | |
442 | ax_simple (ax, aop_lsh); | |
443 | } | |
444 | else if (distance < 0) | |
445 | { | |
446 | ax_const_l (ax, -distance); | |
447 | ax_simple (ax, aop_rsh_unsigned); | |
448 | } | |
449 | } | |
c5aa993b | 450 | \f |
c906108c SS |
451 | |
452 | ||
c906108c SS |
453 | /* Generating bytecode from GDB expressions: symbol references */ |
454 | ||
455 | /* Generate code to push the base address of the argument portion of | |
456 | the top stack frame. */ | |
457 | static void | |
fba45db2 | 458 | gen_frame_args_address (struct agent_expr *ax) |
c906108c | 459 | { |
39d4ef09 AC |
460 | int frame_reg; |
461 | LONGEST frame_offset; | |
c906108c | 462 | |
c7bb205c UW |
463 | gdbarch_virtual_frame_pointer (current_gdbarch, |
464 | ax->scope, &frame_reg, &frame_offset); | |
c5aa993b | 465 | ax_reg (ax, frame_reg); |
c906108c SS |
466 | gen_offset (ax, frame_offset); |
467 | } | |
468 | ||
469 | ||
470 | /* Generate code to push the base address of the locals portion of the | |
471 | top stack frame. */ | |
472 | static void | |
fba45db2 | 473 | gen_frame_locals_address (struct agent_expr *ax) |
c906108c | 474 | { |
39d4ef09 AC |
475 | int frame_reg; |
476 | LONGEST frame_offset; | |
c906108c | 477 | |
c7bb205c UW |
478 | gdbarch_virtual_frame_pointer (current_gdbarch, |
479 | ax->scope, &frame_reg, &frame_offset); | |
c5aa993b | 480 | ax_reg (ax, frame_reg); |
c906108c SS |
481 | gen_offset (ax, frame_offset); |
482 | } | |
483 | ||
484 | ||
485 | /* Generate code to add OFFSET to the top of the stack. Try to | |
486 | generate short and readable code. We use this for getting to | |
487 | variables on the stack, and structure members. If we were | |
488 | programming in ML, it would be clearer why these are the same | |
489 | thing. */ | |
490 | static void | |
fba45db2 | 491 | gen_offset (struct agent_expr *ax, int offset) |
c906108c SS |
492 | { |
493 | /* It would suffice to simply push the offset and add it, but this | |
494 | makes it easier to read positive and negative offsets in the | |
495 | bytecode. */ | |
496 | if (offset > 0) | |
497 | { | |
498 | ax_const_l (ax, offset); | |
499 | ax_simple (ax, aop_add); | |
500 | } | |
501 | else if (offset < 0) | |
502 | { | |
503 | ax_const_l (ax, -offset); | |
504 | ax_simple (ax, aop_sub); | |
505 | } | |
506 | } | |
507 | ||
508 | ||
509 | /* In many cases, a symbol's value is the offset from some other | |
510 | address (stack frame, base register, etc.) Generate code to add | |
511 | VAR's value to the top of the stack. */ | |
512 | static void | |
fba45db2 | 513 | gen_sym_offset (struct agent_expr *ax, struct symbol *var) |
c906108c SS |
514 | { |
515 | gen_offset (ax, SYMBOL_VALUE (var)); | |
516 | } | |
517 | ||
518 | ||
519 | /* Generate code for a variable reference to AX. The variable is the | |
520 | symbol VAR. Set VALUE to describe the result. */ | |
521 | ||
522 | static void | |
fba45db2 | 523 | gen_var_ref (struct agent_expr *ax, struct axs_value *value, struct symbol *var) |
c906108c SS |
524 | { |
525 | /* Dereference any typedefs. */ | |
526 | value->type = check_typedef (SYMBOL_TYPE (var)); | |
527 | ||
528 | /* I'm imitating the code in read_var_value. */ | |
529 | switch (SYMBOL_CLASS (var)) | |
530 | { | |
531 | case LOC_CONST: /* A constant, like an enum value. */ | |
532 | ax_const_l (ax, (LONGEST) SYMBOL_VALUE (var)); | |
533 | value->kind = axs_rvalue; | |
534 | break; | |
535 | ||
536 | case LOC_LABEL: /* A goto label, being used as a value. */ | |
537 | ax_const_l (ax, (LONGEST) SYMBOL_VALUE_ADDRESS (var)); | |
538 | value->kind = axs_rvalue; | |
539 | break; | |
540 | ||
541 | case LOC_CONST_BYTES: | |
8e65ff28 | 542 | internal_error (__FILE__, __LINE__, |
3d263c1d | 543 | _("gen_var_ref: LOC_CONST_BYTES symbols are not supported")); |
c906108c SS |
544 | |
545 | /* Variable at a fixed location in memory. Easy. */ | |
546 | case LOC_STATIC: | |
547 | /* Push the address of the variable. */ | |
548 | ax_const_l (ax, SYMBOL_VALUE_ADDRESS (var)); | |
549 | value->kind = axs_lvalue_memory; | |
550 | break; | |
551 | ||
552 | case LOC_ARG: /* var lives in argument area of frame */ | |
553 | gen_frame_args_address (ax); | |
554 | gen_sym_offset (ax, var); | |
555 | value->kind = axs_lvalue_memory; | |
556 | break; | |
557 | ||
558 | case LOC_REF_ARG: /* As above, but the frame slot really | |
559 | holds the address of the variable. */ | |
560 | gen_frame_args_address (ax); | |
561 | gen_sym_offset (ax, var); | |
562 | /* Don't assume any particular pointer size. */ | |
563 | gen_fetch (ax, lookup_pointer_type (builtin_type_void)); | |
564 | value->kind = axs_lvalue_memory; | |
565 | break; | |
566 | ||
567 | case LOC_LOCAL: /* var lives in locals area of frame */ | |
c906108c SS |
568 | gen_frame_locals_address (ax); |
569 | gen_sym_offset (ax, var); | |
570 | value->kind = axs_lvalue_memory; | |
571 | break; | |
572 | ||
c906108c | 573 | case LOC_TYPEDEF: |
3d263c1d | 574 | error (_("Cannot compute value of typedef `%s'."), |
de5ad195 | 575 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
576 | break; |
577 | ||
578 | case LOC_BLOCK: | |
579 | ax_const_l (ax, BLOCK_START (SYMBOL_BLOCK_VALUE (var))); | |
580 | value->kind = axs_rvalue; | |
581 | break; | |
582 | ||
583 | case LOC_REGISTER: | |
c906108c SS |
584 | /* Don't generate any code at all; in the process of treating |
585 | this as an lvalue or rvalue, the caller will generate the | |
586 | right code. */ | |
587 | value->kind = axs_lvalue_register; | |
588 | value->u.reg = SYMBOL_VALUE (var); | |
589 | break; | |
590 | ||
591 | /* A lot like LOC_REF_ARG, but the pointer lives directly in a | |
2a2d4dc3 AS |
592 | register, not on the stack. Simpler than LOC_REGISTER |
593 | because it's just like any other case where the thing | |
594 | has a real address. */ | |
c906108c SS |
595 | case LOC_REGPARM_ADDR: |
596 | ax_reg (ax, SYMBOL_VALUE (var)); | |
597 | value->kind = axs_lvalue_memory; | |
598 | break; | |
599 | ||
600 | case LOC_UNRESOLVED: | |
601 | { | |
c5aa993b | 602 | struct minimal_symbol *msym |
3567439c | 603 | = lookup_minimal_symbol (SYMBOL_LINKAGE_NAME (var), NULL, NULL); |
c5aa993b | 604 | if (!msym) |
3d263c1d | 605 | error (_("Couldn't resolve symbol `%s'."), SYMBOL_PRINT_NAME (var)); |
c5aa993b | 606 | |
c906108c SS |
607 | /* Push the address of the variable. */ |
608 | ax_const_l (ax, SYMBOL_VALUE_ADDRESS (msym)); | |
609 | value->kind = axs_lvalue_memory; | |
610 | } | |
c5aa993b | 611 | break; |
c906108c | 612 | |
a55cc764 | 613 | case LOC_COMPUTED: |
a67af2b9 AC |
614 | /* FIXME: cagney/2004-01-26: It should be possible to |
615 | unconditionally call the SYMBOL_OPS method when available. | |
d3efc286 | 616 | Unfortunately DWARF 2 stores the frame-base (instead of the |
a67af2b9 AC |
617 | function) location in a function's symbol. Oops! For the |
618 | moment enable this when/where applicable. */ | |
619 | SYMBOL_OPS (var)->tracepoint_var_ref (var, ax, value); | |
a55cc764 DJ |
620 | break; |
621 | ||
c906108c | 622 | case LOC_OPTIMIZED_OUT: |
3d263c1d | 623 | error (_("The variable `%s' has been optimized out."), |
de5ad195 | 624 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
625 | break; |
626 | ||
627 | default: | |
3d263c1d | 628 | error (_("Cannot find value of botched symbol `%s'."), |
de5ad195 | 629 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
630 | break; |
631 | } | |
632 | } | |
c5aa993b | 633 | \f |
c906108c SS |
634 | |
635 | ||
c906108c SS |
636 | /* Generating bytecode from GDB expressions: literals */ |
637 | ||
638 | static void | |
fba45db2 KB |
639 | gen_int_literal (struct agent_expr *ax, struct axs_value *value, LONGEST k, |
640 | struct type *type) | |
c906108c SS |
641 | { |
642 | ax_const_l (ax, k); | |
643 | value->kind = axs_rvalue; | |
648027cc | 644 | value->type = check_typedef (type); |
c906108c | 645 | } |
c5aa993b | 646 | \f |
c906108c SS |
647 | |
648 | ||
c906108c SS |
649 | /* Generating bytecode from GDB expressions: unary conversions, casts */ |
650 | ||
651 | /* Take what's on the top of the stack (as described by VALUE), and | |
652 | try to make an rvalue out of it. Signal an error if we can't do | |
653 | that. */ | |
654 | static void | |
fba45db2 | 655 | require_rvalue (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
656 | { |
657 | switch (value->kind) | |
658 | { | |
659 | case axs_rvalue: | |
660 | /* It's already an rvalue. */ | |
661 | break; | |
662 | ||
663 | case axs_lvalue_memory: | |
664 | /* The top of stack is the address of the object. Dereference. */ | |
665 | gen_fetch (ax, value->type); | |
666 | break; | |
667 | ||
668 | case axs_lvalue_register: | |
669 | /* There's nothing on the stack, but value->u.reg is the | |
670 | register number containing the value. | |
671 | ||
c5aa993b JM |
672 | When we add floating-point support, this is going to have to |
673 | change. What about SPARC register pairs, for example? */ | |
c906108c SS |
674 | ax_reg (ax, value->u.reg); |
675 | gen_extend (ax, value->type); | |
676 | break; | |
677 | } | |
678 | ||
679 | value->kind = axs_rvalue; | |
680 | } | |
681 | ||
682 | ||
683 | /* Assume the top of the stack is described by VALUE, and perform the | |
684 | usual unary conversions. This is motivated by ANSI 6.2.2, but of | |
685 | course GDB expressions are not ANSI; they're the mishmash union of | |
686 | a bunch of languages. Rah. | |
687 | ||
688 | NOTE! This function promises to produce an rvalue only when the | |
689 | incoming value is of an appropriate type. In other words, the | |
690 | consumer of the value this function produces may assume the value | |
691 | is an rvalue only after checking its type. | |
692 | ||
693 | The immediate issue is that if the user tries to use a structure or | |
694 | union as an operand of, say, the `+' operator, we don't want to try | |
695 | to convert that structure to an rvalue; require_rvalue will bomb on | |
696 | structs and unions. Rather, we want to simply pass the struct | |
697 | lvalue through unchanged, and let `+' raise an error. */ | |
698 | ||
699 | static void | |
fba45db2 | 700 | gen_usual_unary (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
701 | { |
702 | /* We don't have to generate any code for the usual integral | |
703 | conversions, since values are always represented as full-width on | |
704 | the stack. Should we tweak the type? */ | |
705 | ||
706 | /* Some types require special handling. */ | |
0004e5a2 | 707 | switch (TYPE_CODE (value->type)) |
c906108c SS |
708 | { |
709 | /* Functions get converted to a pointer to the function. */ | |
710 | case TYPE_CODE_FUNC: | |
711 | value->type = lookup_pointer_type (value->type); | |
712 | value->kind = axs_rvalue; /* Should always be true, but just in case. */ | |
713 | break; | |
714 | ||
715 | /* Arrays get converted to a pointer to their first element, and | |
c5aa993b | 716 | are no longer an lvalue. */ |
c906108c SS |
717 | case TYPE_CODE_ARRAY: |
718 | { | |
719 | struct type *elements = TYPE_TARGET_TYPE (value->type); | |
720 | value->type = lookup_pointer_type (elements); | |
721 | value->kind = axs_rvalue; | |
722 | /* We don't need to generate any code; the address of the array | |
723 | is also the address of its first element. */ | |
724 | } | |
c5aa993b | 725 | break; |
c906108c | 726 | |
c5aa993b JM |
727 | /* Don't try to convert structures and unions to rvalues. Let the |
728 | consumer signal an error. */ | |
c906108c SS |
729 | case TYPE_CODE_STRUCT: |
730 | case TYPE_CODE_UNION: | |
731 | return; | |
732 | ||
733 | /* If the value is an enum, call it an integer. */ | |
734 | case TYPE_CODE_ENUM: | |
735 | value->type = builtin_type_int; | |
736 | break; | |
737 | } | |
738 | ||
739 | /* If the value is an lvalue, dereference it. */ | |
740 | require_rvalue (ax, value); | |
741 | } | |
742 | ||
743 | ||
744 | /* Return non-zero iff the type TYPE1 is considered "wider" than the | |
745 | type TYPE2, according to the rules described in gen_usual_arithmetic. */ | |
746 | static int | |
fba45db2 | 747 | type_wider_than (struct type *type1, struct type *type2) |
c906108c SS |
748 | { |
749 | return (TYPE_LENGTH (type1) > TYPE_LENGTH (type2) | |
750 | || (TYPE_LENGTH (type1) == TYPE_LENGTH (type2) | |
751 | && TYPE_UNSIGNED (type1) | |
c5aa993b | 752 | && !TYPE_UNSIGNED (type2))); |
c906108c SS |
753 | } |
754 | ||
755 | ||
756 | /* Return the "wider" of the two types TYPE1 and TYPE2. */ | |
757 | static struct type * | |
fba45db2 | 758 | max_type (struct type *type1, struct type *type2) |
c906108c SS |
759 | { |
760 | return type_wider_than (type1, type2) ? type1 : type2; | |
761 | } | |
762 | ||
763 | ||
764 | /* Generate code to convert a scalar value of type FROM to type TO. */ | |
765 | static void | |
fba45db2 | 766 | gen_conversion (struct agent_expr *ax, struct type *from, struct type *to) |
c906108c SS |
767 | { |
768 | /* Perhaps there is a more graceful way to state these rules. */ | |
769 | ||
770 | /* If we're converting to a narrower type, then we need to clear out | |
771 | the upper bits. */ | |
772 | if (TYPE_LENGTH (to) < TYPE_LENGTH (from)) | |
773 | gen_extend (ax, from); | |
774 | ||
775 | /* If the two values have equal width, but different signednesses, | |
776 | then we need to extend. */ | |
777 | else if (TYPE_LENGTH (to) == TYPE_LENGTH (from)) | |
778 | { | |
779 | if (TYPE_UNSIGNED (from) != TYPE_UNSIGNED (to)) | |
780 | gen_extend (ax, to); | |
781 | } | |
782 | ||
783 | /* If we're converting to a wider type, and becoming unsigned, then | |
784 | we need to zero out any possible sign bits. */ | |
785 | else if (TYPE_LENGTH (to) > TYPE_LENGTH (from)) | |
786 | { | |
787 | if (TYPE_UNSIGNED (to)) | |
788 | gen_extend (ax, to); | |
789 | } | |
790 | } | |
791 | ||
792 | ||
793 | /* Return non-zero iff the type FROM will require any bytecodes to be | |
794 | emitted to be converted to the type TO. */ | |
795 | static int | |
fba45db2 | 796 | is_nontrivial_conversion (struct type *from, struct type *to) |
c906108c SS |
797 | { |
798 | struct agent_expr *ax = new_agent_expr (0); | |
799 | int nontrivial; | |
800 | ||
801 | /* Actually generate the code, and see if anything came out. At the | |
802 | moment, it would be trivial to replicate the code in | |
803 | gen_conversion here, but in the future, when we're supporting | |
804 | floating point and the like, it may not be. Doing things this | |
805 | way allows this function to be independent of the logic in | |
806 | gen_conversion. */ | |
807 | gen_conversion (ax, from, to); | |
808 | nontrivial = ax->len > 0; | |
809 | free_agent_expr (ax); | |
810 | return nontrivial; | |
811 | } | |
812 | ||
813 | ||
814 | /* Generate code to perform the "usual arithmetic conversions" (ANSI C | |
815 | 6.2.1.5) for the two operands of an arithmetic operator. This | |
816 | effectively finds a "least upper bound" type for the two arguments, | |
817 | and promotes each argument to that type. *VALUE1 and *VALUE2 | |
818 | describe the values as they are passed in, and as they are left. */ | |
819 | static void | |
fba45db2 KB |
820 | gen_usual_arithmetic (struct agent_expr *ax, struct axs_value *value1, |
821 | struct axs_value *value2) | |
c906108c SS |
822 | { |
823 | /* Do the usual binary conversions. */ | |
824 | if (TYPE_CODE (value1->type) == TYPE_CODE_INT | |
825 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
826 | { | |
827 | /* The ANSI integral promotions seem to work this way: Order the | |
c5aa993b JM |
828 | integer types by size, and then by signedness: an n-bit |
829 | unsigned type is considered "wider" than an n-bit signed | |
830 | type. Promote to the "wider" of the two types, and always | |
831 | promote at least to int. */ | |
c906108c SS |
832 | struct type *target = max_type (builtin_type_int, |
833 | max_type (value1->type, value2->type)); | |
834 | ||
835 | /* Deal with value2, on the top of the stack. */ | |
836 | gen_conversion (ax, value2->type, target); | |
837 | ||
838 | /* Deal with value1, not on the top of the stack. Don't | |
839 | generate the `swap' instructions if we're not actually going | |
840 | to do anything. */ | |
841 | if (is_nontrivial_conversion (value1->type, target)) | |
842 | { | |
843 | ax_simple (ax, aop_swap); | |
844 | gen_conversion (ax, value1->type, target); | |
845 | ax_simple (ax, aop_swap); | |
846 | } | |
847 | ||
648027cc | 848 | value1->type = value2->type = check_typedef (target); |
c906108c SS |
849 | } |
850 | } | |
851 | ||
852 | ||
853 | /* Generate code to perform the integral promotions (ANSI 6.2.1.1) on | |
854 | the value on the top of the stack, as described by VALUE. Assume | |
855 | the value has integral type. */ | |
856 | static void | |
fba45db2 | 857 | gen_integral_promotions (struct agent_expr *ax, struct axs_value *value) |
c906108c | 858 | { |
c5aa993b | 859 | if (!type_wider_than (value->type, builtin_type_int)) |
c906108c SS |
860 | { |
861 | gen_conversion (ax, value->type, builtin_type_int); | |
862 | value->type = builtin_type_int; | |
863 | } | |
c5aa993b | 864 | else if (!type_wider_than (value->type, builtin_type_unsigned_int)) |
c906108c SS |
865 | { |
866 | gen_conversion (ax, value->type, builtin_type_unsigned_int); | |
867 | value->type = builtin_type_unsigned_int; | |
868 | } | |
869 | } | |
870 | ||
871 | ||
872 | /* Generate code for a cast to TYPE. */ | |
873 | static void | |
fba45db2 | 874 | gen_cast (struct agent_expr *ax, struct axs_value *value, struct type *type) |
c906108c SS |
875 | { |
876 | /* GCC does allow casts to yield lvalues, so this should be fixed | |
877 | before merging these changes into the trunk. */ | |
878 | require_rvalue (ax, value); | |
879 | /* Dereference typedefs. */ | |
880 | type = check_typedef (type); | |
881 | ||
0004e5a2 | 882 | switch (TYPE_CODE (type)) |
c906108c SS |
883 | { |
884 | case TYPE_CODE_PTR: | |
885 | /* It's implementation-defined, and I'll bet this is what GCC | |
886 | does. */ | |
887 | break; | |
888 | ||
889 | case TYPE_CODE_ARRAY: | |
890 | case TYPE_CODE_STRUCT: | |
891 | case TYPE_CODE_UNION: | |
892 | case TYPE_CODE_FUNC: | |
3d263c1d | 893 | error (_("Invalid type cast: intended type must be scalar.")); |
c906108c SS |
894 | |
895 | case TYPE_CODE_ENUM: | |
896 | /* We don't have to worry about the size of the value, because | |
897 | all our integral values are fully sign-extended, and when | |
898 | casting pointers we can do anything we like. Is there any | |
74b35824 JB |
899 | way for us to know what GCC actually does with a cast like |
900 | this? */ | |
c906108c | 901 | break; |
c5aa993b | 902 | |
c906108c SS |
903 | case TYPE_CODE_INT: |
904 | gen_conversion (ax, value->type, type); | |
905 | break; | |
906 | ||
907 | case TYPE_CODE_VOID: | |
908 | /* We could pop the value, and rely on everyone else to check | |
c5aa993b JM |
909 | the type and notice that this value doesn't occupy a stack |
910 | slot. But for now, leave the value on the stack, and | |
911 | preserve the "value == stack element" assumption. */ | |
c906108c SS |
912 | break; |
913 | ||
914 | default: | |
3d263c1d | 915 | error (_("Casts to requested type are not yet implemented.")); |
c906108c SS |
916 | } |
917 | ||
918 | value->type = type; | |
919 | } | |
c5aa993b | 920 | \f |
c906108c SS |
921 | |
922 | ||
c906108c SS |
923 | /* Generating bytecode from GDB expressions: arithmetic */ |
924 | ||
925 | /* Scale the integer on the top of the stack by the size of the target | |
926 | of the pointer type TYPE. */ | |
927 | static void | |
fba45db2 | 928 | gen_scale (struct agent_expr *ax, enum agent_op op, struct type *type) |
c906108c SS |
929 | { |
930 | struct type *element = TYPE_TARGET_TYPE (type); | |
931 | ||
0004e5a2 | 932 | if (TYPE_LENGTH (element) != 1) |
c906108c | 933 | { |
0004e5a2 | 934 | ax_const_l (ax, TYPE_LENGTH (element)); |
c906108c SS |
935 | ax_simple (ax, op); |
936 | } | |
937 | } | |
938 | ||
939 | ||
940 | /* Generate code for an addition; non-trivial because we deal with | |
941 | pointer arithmetic. We set VALUE to describe the result value; we | |
942 | assume VALUE1 and VALUE2 describe the two operands, and that | |
943 | they've undergone the usual binary conversions. Used by both | |
944 | BINOP_ADD and BINOP_SUBSCRIPT. NAME is used in error messages. */ | |
945 | static void | |
fba45db2 KB |
946 | gen_add (struct agent_expr *ax, struct axs_value *value, |
947 | struct axs_value *value1, struct axs_value *value2, char *name) | |
c906108c SS |
948 | { |
949 | /* Is it INT+PTR? */ | |
0004e5a2 DJ |
950 | if (TYPE_CODE (value1->type) == TYPE_CODE_INT |
951 | && TYPE_CODE (value2->type) == TYPE_CODE_PTR) | |
c906108c SS |
952 | { |
953 | /* Swap the values and proceed normally. */ | |
954 | ax_simple (ax, aop_swap); | |
955 | gen_scale (ax, aop_mul, value2->type); | |
956 | ax_simple (ax, aop_add); | |
c5aa993b | 957 | gen_extend (ax, value2->type); /* Catch overflow. */ |
c906108c SS |
958 | value->type = value2->type; |
959 | } | |
960 | ||
961 | /* Is it PTR+INT? */ | |
0004e5a2 DJ |
962 | else if (TYPE_CODE (value1->type) == TYPE_CODE_PTR |
963 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
c906108c SS |
964 | { |
965 | gen_scale (ax, aop_mul, value1->type); | |
966 | ax_simple (ax, aop_add); | |
c5aa993b | 967 | gen_extend (ax, value1->type); /* Catch overflow. */ |
c906108c SS |
968 | value->type = value1->type; |
969 | } | |
970 | ||
971 | /* Must be number + number; the usual binary conversions will have | |
972 | brought them both to the same width. */ | |
0004e5a2 DJ |
973 | else if (TYPE_CODE (value1->type) == TYPE_CODE_INT |
974 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
c906108c SS |
975 | { |
976 | ax_simple (ax, aop_add); | |
c5aa993b | 977 | gen_extend (ax, value1->type); /* Catch overflow. */ |
c906108c SS |
978 | value->type = value1->type; |
979 | } | |
980 | ||
981 | else | |
3d263c1d | 982 | error (_("Invalid combination of types in %s."), name); |
c906108c SS |
983 | |
984 | value->kind = axs_rvalue; | |
985 | } | |
986 | ||
987 | ||
988 | /* Generate code for an addition; non-trivial because we have to deal | |
989 | with pointer arithmetic. We set VALUE to describe the result | |
990 | value; we assume VALUE1 and VALUE2 describe the two operands, and | |
991 | that they've undergone the usual binary conversions. */ | |
992 | static void | |
fba45db2 KB |
993 | gen_sub (struct agent_expr *ax, struct axs_value *value, |
994 | struct axs_value *value1, struct axs_value *value2) | |
c906108c | 995 | { |
0004e5a2 | 996 | if (TYPE_CODE (value1->type) == TYPE_CODE_PTR) |
c906108c SS |
997 | { |
998 | /* Is it PTR - INT? */ | |
0004e5a2 | 999 | if (TYPE_CODE (value2->type) == TYPE_CODE_INT) |
c906108c SS |
1000 | { |
1001 | gen_scale (ax, aop_mul, value1->type); | |
1002 | ax_simple (ax, aop_sub); | |
c5aa993b | 1003 | gen_extend (ax, value1->type); /* Catch overflow. */ |
c906108c SS |
1004 | value->type = value1->type; |
1005 | } | |
1006 | ||
1007 | /* Is it PTR - PTR? Strictly speaking, the types ought to | |
c5aa993b JM |
1008 | match, but this is what the normal GDB expression evaluator |
1009 | tests for. */ | |
0004e5a2 | 1010 | else if (TYPE_CODE (value2->type) == TYPE_CODE_PTR |
c906108c SS |
1011 | && (TYPE_LENGTH (TYPE_TARGET_TYPE (value1->type)) |
1012 | == TYPE_LENGTH (TYPE_TARGET_TYPE (value2->type)))) | |
1013 | { | |
1014 | ax_simple (ax, aop_sub); | |
1015 | gen_scale (ax, aop_div_unsigned, value1->type); | |
c5aa993b | 1016 | value->type = builtin_type_long; /* FIXME --- should be ptrdiff_t */ |
c906108c SS |
1017 | } |
1018 | else | |
3d263c1d | 1019 | error (_("\ |
c906108c | 1020 | First argument of `-' is a pointer, but second argument is neither\n\ |
3d263c1d | 1021 | an integer nor a pointer of the same type.")); |
c906108c SS |
1022 | } |
1023 | ||
1024 | /* Must be number + number. */ | |
0004e5a2 DJ |
1025 | else if (TYPE_CODE (value1->type) == TYPE_CODE_INT |
1026 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
c906108c SS |
1027 | { |
1028 | ax_simple (ax, aop_sub); | |
c5aa993b | 1029 | gen_extend (ax, value1->type); /* Catch overflow. */ |
c906108c SS |
1030 | value->type = value1->type; |
1031 | } | |
c5aa993b | 1032 | |
c906108c | 1033 | else |
3d263c1d | 1034 | error (_("Invalid combination of types in subtraction.")); |
c906108c SS |
1035 | |
1036 | value->kind = axs_rvalue; | |
1037 | } | |
1038 | ||
1039 | /* Generate code for a binary operator that doesn't do pointer magic. | |
1040 | We set VALUE to describe the result value; we assume VALUE1 and | |
1041 | VALUE2 describe the two operands, and that they've undergone the | |
1042 | usual binary conversions. MAY_CARRY should be non-zero iff the | |
1043 | result needs to be extended. NAME is the English name of the | |
1044 | operator, used in error messages */ | |
1045 | static void | |
fba45db2 KB |
1046 | gen_binop (struct agent_expr *ax, struct axs_value *value, |
1047 | struct axs_value *value1, struct axs_value *value2, enum agent_op op, | |
1048 | enum agent_op op_unsigned, int may_carry, char *name) | |
c906108c SS |
1049 | { |
1050 | /* We only handle INT op INT. */ | |
0004e5a2 DJ |
1051 | if ((TYPE_CODE (value1->type) != TYPE_CODE_INT) |
1052 | || (TYPE_CODE (value2->type) != TYPE_CODE_INT)) | |
3d263c1d | 1053 | error (_("Invalid combination of types in %s."), name); |
c5aa993b | 1054 | |
c906108c SS |
1055 | ax_simple (ax, |
1056 | TYPE_UNSIGNED (value1->type) ? op_unsigned : op); | |
1057 | if (may_carry) | |
c5aa993b | 1058 | gen_extend (ax, value1->type); /* catch overflow */ |
c906108c SS |
1059 | value->type = value1->type; |
1060 | value->kind = axs_rvalue; | |
1061 | } | |
1062 | ||
1063 | ||
1064 | static void | |
fba45db2 | 1065 | gen_logical_not (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1066 | { |
1067 | if (TYPE_CODE (value->type) != TYPE_CODE_INT | |
1068 | && TYPE_CODE (value->type) != TYPE_CODE_PTR) | |
3d263c1d | 1069 | error (_("Invalid type of operand to `!'.")); |
c906108c SS |
1070 | |
1071 | gen_usual_unary (ax, value); | |
1072 | ax_simple (ax, aop_log_not); | |
1073 | value->type = builtin_type_int; | |
1074 | } | |
1075 | ||
1076 | ||
1077 | static void | |
fba45db2 | 1078 | gen_complement (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1079 | { |
1080 | if (TYPE_CODE (value->type) != TYPE_CODE_INT) | |
3d263c1d | 1081 | error (_("Invalid type of operand to `~'.")); |
c906108c SS |
1082 | |
1083 | gen_usual_unary (ax, value); | |
1084 | gen_integral_promotions (ax, value); | |
1085 | ax_simple (ax, aop_bit_not); | |
1086 | gen_extend (ax, value->type); | |
1087 | } | |
c5aa993b | 1088 | \f |
c906108c SS |
1089 | |
1090 | ||
c906108c SS |
1091 | /* Generating bytecode from GDB expressions: * & . -> @ sizeof */ |
1092 | ||
1093 | /* Dereference the value on the top of the stack. */ | |
1094 | static void | |
fba45db2 | 1095 | gen_deref (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1096 | { |
1097 | /* The caller should check the type, because several operators use | |
1098 | this, and we don't know what error message to generate. */ | |
0004e5a2 | 1099 | if (TYPE_CODE (value->type) != TYPE_CODE_PTR) |
8e65ff28 | 1100 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1101 | _("gen_deref: expected a pointer")); |
c906108c SS |
1102 | |
1103 | /* We've got an rvalue now, which is a pointer. We want to yield an | |
1104 | lvalue, whose address is exactly that pointer. So we don't | |
1105 | actually emit any code; we just change the type from "Pointer to | |
1106 | T" to "T", and mark the value as an lvalue in memory. Leave it | |
1107 | to the consumer to actually dereference it. */ | |
1108 | value->type = check_typedef (TYPE_TARGET_TYPE (value->type)); | |
0004e5a2 | 1109 | value->kind = ((TYPE_CODE (value->type) == TYPE_CODE_FUNC) |
c906108c SS |
1110 | ? axs_rvalue : axs_lvalue_memory); |
1111 | } | |
1112 | ||
1113 | ||
1114 | /* Produce the address of the lvalue on the top of the stack. */ | |
1115 | static void | |
fba45db2 | 1116 | gen_address_of (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1117 | { |
1118 | /* Special case for taking the address of a function. The ANSI | |
1119 | standard describes this as a special case, too, so this | |
1120 | arrangement is not without motivation. */ | |
0004e5a2 | 1121 | if (TYPE_CODE (value->type) == TYPE_CODE_FUNC) |
c906108c SS |
1122 | /* The value's already an rvalue on the stack, so we just need to |
1123 | change the type. */ | |
1124 | value->type = lookup_pointer_type (value->type); | |
1125 | else | |
1126 | switch (value->kind) | |
1127 | { | |
1128 | case axs_rvalue: | |
3d263c1d | 1129 | error (_("Operand of `&' is an rvalue, which has no address.")); |
c906108c SS |
1130 | |
1131 | case axs_lvalue_register: | |
3d263c1d | 1132 | error (_("Operand of `&' is in a register, and has no address.")); |
c906108c SS |
1133 | |
1134 | case axs_lvalue_memory: | |
1135 | value->kind = axs_rvalue; | |
1136 | value->type = lookup_pointer_type (value->type); | |
1137 | break; | |
1138 | } | |
1139 | } | |
1140 | ||
1141 | ||
1142 | /* A lot of this stuff will have to change to support C++. But we're | |
1143 | not going to deal with that at the moment. */ | |
1144 | ||
1145 | /* Find the field in the structure type TYPE named NAME, and return | |
1146 | its index in TYPE's field array. */ | |
1147 | static int | |
fba45db2 | 1148 | find_field (struct type *type, char *name) |
c906108c SS |
1149 | { |
1150 | int i; | |
1151 | ||
1152 | CHECK_TYPEDEF (type); | |
1153 | ||
1154 | /* Make sure this isn't C++. */ | |
1155 | if (TYPE_N_BASECLASSES (type) != 0) | |
8e65ff28 | 1156 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1157 | _("find_field: derived classes supported")); |
c906108c SS |
1158 | |
1159 | for (i = 0; i < TYPE_NFIELDS (type); i++) | |
1160 | { | |
1161 | char *this_name = TYPE_FIELD_NAME (type, i); | |
1162 | ||
747f3d18 MS |
1163 | if (this_name) |
1164 | { | |
1165 | if (strcmp (name, this_name) == 0) | |
1166 | return i; | |
c906108c | 1167 | |
747f3d18 MS |
1168 | if (this_name[0] == '\0') |
1169 | internal_error (__FILE__, __LINE__, | |
1170 | _("find_field: anonymous unions not supported")); | |
1171 | } | |
c906108c SS |
1172 | } |
1173 | ||
3d263c1d | 1174 | error (_("Couldn't find member named `%s' in struct/union `%s'"), |
7495dfdb | 1175 | name, TYPE_TAG_NAME (type)); |
c906108c SS |
1176 | |
1177 | return 0; | |
1178 | } | |
1179 | ||
1180 | ||
1181 | /* Generate code to push the value of a bitfield of a structure whose | |
1182 | address is on the top of the stack. START and END give the | |
1183 | starting and one-past-ending *bit* numbers of the field within the | |
1184 | structure. */ | |
1185 | static void | |
fba45db2 KB |
1186 | gen_bitfield_ref (struct agent_expr *ax, struct axs_value *value, |
1187 | struct type *type, int start, int end) | |
c906108c SS |
1188 | { |
1189 | /* Note that ops[i] fetches 8 << i bits. */ | |
1190 | static enum agent_op ops[] | |
c5aa993b JM |
1191 | = |
1192 | {aop_ref8, aop_ref16, aop_ref32, aop_ref64}; | |
c906108c SS |
1193 | static int num_ops = (sizeof (ops) / sizeof (ops[0])); |
1194 | ||
1195 | /* We don't want to touch any byte that the bitfield doesn't | |
1196 | actually occupy; we shouldn't make any accesses we're not | |
1197 | explicitly permitted to. We rely here on the fact that the | |
1198 | bytecode `ref' operators work on unaligned addresses. | |
1199 | ||
1200 | It takes some fancy footwork to get the stack to work the way | |
1201 | we'd like. Say we're retrieving a bitfield that requires three | |
1202 | fetches. Initially, the stack just contains the address: | |
c5aa993b | 1203 | addr |
c906108c | 1204 | For the first fetch, we duplicate the address |
c5aa993b | 1205 | addr addr |
c906108c SS |
1206 | then add the byte offset, do the fetch, and shift and mask as |
1207 | needed, yielding a fragment of the value, properly aligned for | |
1208 | the final bitwise or: | |
c5aa993b | 1209 | addr frag1 |
c906108c | 1210 | then we swap, and repeat the process: |
c5aa993b JM |
1211 | frag1 addr --- address on top |
1212 | frag1 addr addr --- duplicate it | |
1213 | frag1 addr frag2 --- get second fragment | |
1214 | frag1 frag2 addr --- swap again | |
1215 | frag1 frag2 frag3 --- get third fragment | |
c906108c SS |
1216 | Notice that, since the third fragment is the last one, we don't |
1217 | bother duplicating the address this time. Now we have all the | |
1218 | fragments on the stack, and we can simply `or' them together, | |
1219 | yielding the final value of the bitfield. */ | |
1220 | ||
1221 | /* The first and one-after-last bits in the field, but rounded down | |
1222 | and up to byte boundaries. */ | |
1223 | int bound_start = (start / TARGET_CHAR_BIT) * TARGET_CHAR_BIT; | |
c5aa993b JM |
1224 | int bound_end = (((end + TARGET_CHAR_BIT - 1) |
1225 | / TARGET_CHAR_BIT) | |
1226 | * TARGET_CHAR_BIT); | |
c906108c SS |
1227 | |
1228 | /* current bit offset within the structure */ | |
1229 | int offset; | |
1230 | ||
1231 | /* The index in ops of the opcode we're considering. */ | |
1232 | int op; | |
1233 | ||
1234 | /* The number of fragments we generated in the process. Probably | |
1235 | equal to the number of `one' bits in bytesize, but who cares? */ | |
1236 | int fragment_count; | |
1237 | ||
1238 | /* Dereference any typedefs. */ | |
1239 | type = check_typedef (type); | |
1240 | ||
1241 | /* Can we fetch the number of bits requested at all? */ | |
1242 | if ((end - start) > ((1 << num_ops) * 8)) | |
8e65ff28 | 1243 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1244 | _("gen_bitfield_ref: bitfield too wide")); |
c906108c SS |
1245 | |
1246 | /* Note that we know here that we only need to try each opcode once. | |
1247 | That may not be true on machines with weird byte sizes. */ | |
1248 | offset = bound_start; | |
1249 | fragment_count = 0; | |
1250 | for (op = num_ops - 1; op >= 0; op--) | |
1251 | { | |
1252 | /* number of bits that ops[op] would fetch */ | |
1253 | int op_size = 8 << op; | |
1254 | ||
1255 | /* The stack at this point, from bottom to top, contains zero or | |
c5aa993b JM |
1256 | more fragments, then the address. */ |
1257 | ||
c906108c SS |
1258 | /* Does this fetch fit within the bitfield? */ |
1259 | if (offset + op_size <= bound_end) | |
1260 | { | |
1261 | /* Is this the last fragment? */ | |
1262 | int last_frag = (offset + op_size == bound_end); | |
1263 | ||
c5aa993b JM |
1264 | if (!last_frag) |
1265 | ax_simple (ax, aop_dup); /* keep a copy of the address */ | |
1266 | ||
c906108c SS |
1267 | /* Add the offset. */ |
1268 | gen_offset (ax, offset / TARGET_CHAR_BIT); | |
1269 | ||
1270 | if (trace_kludge) | |
1271 | { | |
1272 | /* Record the area of memory we're about to fetch. */ | |
1273 | ax_trace_quick (ax, op_size / TARGET_CHAR_BIT); | |
1274 | } | |
1275 | ||
1276 | /* Perform the fetch. */ | |
1277 | ax_simple (ax, ops[op]); | |
c5aa993b JM |
1278 | |
1279 | /* Shift the bits we have to their proper position. | |
c906108c SS |
1280 | gen_left_shift will generate right shifts when the operand |
1281 | is negative. | |
1282 | ||
c5aa993b JM |
1283 | A big-endian field diagram to ponder: |
1284 | byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 byte 6 byte 7 | |
1285 | +------++------++------++------++------++------++------++------+ | |
1286 | xxxxAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBCCCCCxxxxxxxxxxx | |
1287 | ^ ^ ^ ^ | |
1288 | bit number 16 32 48 53 | |
c906108c SS |
1289 | These are bit numbers as supplied by GDB. Note that the |
1290 | bit numbers run from right to left once you've fetched the | |
1291 | value! | |
1292 | ||
c5aa993b JM |
1293 | A little-endian field diagram to ponder: |
1294 | byte 7 byte 6 byte 5 byte 4 byte 3 byte 2 byte 1 byte 0 | |
1295 | +------++------++------++------++------++------++------++------+ | |
1296 | xxxxxxxxxxxAAAAABBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCCCCCCCCCCCxxxx | |
1297 | ^ ^ ^ ^ ^ | |
1298 | bit number 48 32 16 4 0 | |
1299 | ||
1300 | In both cases, the most significant end is on the left | |
1301 | (i.e. normal numeric writing order), which means that you | |
1302 | don't go crazy thinking about `left' and `right' shifts. | |
1303 | ||
1304 | We don't have to worry about masking yet: | |
1305 | - If they contain garbage off the least significant end, then we | |
1306 | must be looking at the low end of the field, and the right | |
1307 | shift will wipe them out. | |
1308 | - If they contain garbage off the most significant end, then we | |
1309 | must be looking at the most significant end of the word, and | |
1310 | the sign/zero extension will wipe them out. | |
1311 | - If we're in the interior of the word, then there is no garbage | |
1312 | on either end, because the ref operators zero-extend. */ | |
0d20ae72 | 1313 | if (gdbarch_byte_order (current_gdbarch) == BFD_ENDIAN_BIG) |
c906108c | 1314 | gen_left_shift (ax, end - (offset + op_size)); |
c5aa993b | 1315 | else |
c906108c SS |
1316 | gen_left_shift (ax, offset - start); |
1317 | ||
c5aa993b | 1318 | if (!last_frag) |
c906108c SS |
1319 | /* Bring the copy of the address up to the top. */ |
1320 | ax_simple (ax, aop_swap); | |
1321 | ||
1322 | offset += op_size; | |
1323 | fragment_count++; | |
1324 | } | |
1325 | } | |
1326 | ||
1327 | /* Generate enough bitwise `or' operations to combine all the | |
1328 | fragments we left on the stack. */ | |
1329 | while (fragment_count-- > 1) | |
1330 | ax_simple (ax, aop_bit_or); | |
1331 | ||
1332 | /* Sign- or zero-extend the value as appropriate. */ | |
1333 | ((TYPE_UNSIGNED (type) ? ax_zero_ext : ax_ext) (ax, end - start)); | |
1334 | ||
1335 | /* This is *not* an lvalue. Ugh. */ | |
1336 | value->kind = axs_rvalue; | |
1337 | value->type = type; | |
1338 | } | |
1339 | ||
1340 | ||
1341 | /* Generate code to reference the member named FIELD of a structure or | |
1342 | union. The top of the stack, as described by VALUE, should have | |
1343 | type (pointer to a)* struct/union. OPERATOR_NAME is the name of | |
1344 | the operator being compiled, and OPERAND_NAME is the kind of thing | |
1345 | it operates on; we use them in error messages. */ | |
1346 | static void | |
fba45db2 KB |
1347 | gen_struct_ref (struct agent_expr *ax, struct axs_value *value, char *field, |
1348 | char *operator_name, char *operand_name) | |
c906108c SS |
1349 | { |
1350 | struct type *type; | |
1351 | int i; | |
1352 | ||
1353 | /* Follow pointers until we reach a non-pointer. These aren't the C | |
1354 | semantics, but they're what the normal GDB evaluator does, so we | |
1355 | should at least be consistent. */ | |
0004e5a2 | 1356 | while (TYPE_CODE (value->type) == TYPE_CODE_PTR) |
c906108c SS |
1357 | { |
1358 | gen_usual_unary (ax, value); | |
1359 | gen_deref (ax, value); | |
1360 | } | |
e8860ec2 | 1361 | type = check_typedef (value->type); |
c906108c SS |
1362 | |
1363 | /* This must yield a structure or a union. */ | |
1364 | if (TYPE_CODE (type) != TYPE_CODE_STRUCT | |
1365 | && TYPE_CODE (type) != TYPE_CODE_UNION) | |
3d263c1d | 1366 | error (_("The left operand of `%s' is not a %s."), |
c906108c SS |
1367 | operator_name, operand_name); |
1368 | ||
1369 | /* And it must be in memory; we don't deal with structure rvalues, | |
1370 | or structures living in registers. */ | |
1371 | if (value->kind != axs_lvalue_memory) | |
3d263c1d | 1372 | error (_("Structure does not live in memory.")); |
c906108c SS |
1373 | |
1374 | i = find_field (type, field); | |
c5aa993b | 1375 | |
c906108c SS |
1376 | /* Is this a bitfield? */ |
1377 | if (TYPE_FIELD_PACKED (type, i)) | |
1378 | gen_bitfield_ref (ax, value, TYPE_FIELD_TYPE (type, i), | |
1379 | TYPE_FIELD_BITPOS (type, i), | |
1380 | (TYPE_FIELD_BITPOS (type, i) | |
1381 | + TYPE_FIELD_BITSIZE (type, i))); | |
1382 | else | |
1383 | { | |
1384 | gen_offset (ax, TYPE_FIELD_BITPOS (type, i) / TARGET_CHAR_BIT); | |
1385 | value->kind = axs_lvalue_memory; | |
1386 | value->type = TYPE_FIELD_TYPE (type, i); | |
1387 | } | |
1388 | } | |
1389 | ||
1390 | ||
1391 | /* Generate code for GDB's magical `repeat' operator. | |
1392 | LVALUE @ INT creates an array INT elements long, and whose elements | |
1393 | have the same type as LVALUE, located in memory so that LVALUE is | |
1394 | its first element. For example, argv[0]@argc gives you the array | |
1395 | of command-line arguments. | |
1396 | ||
1397 | Unfortunately, because we have to know the types before we actually | |
1398 | have a value for the expression, we can't implement this perfectly | |
1399 | without changing the type system, having values that occupy two | |
1400 | stack slots, doing weird things with sizeof, etc. So we require | |
1401 | the right operand to be a constant expression. */ | |
1402 | static void | |
fba45db2 KB |
1403 | gen_repeat (union exp_element **pc, struct agent_expr *ax, |
1404 | struct axs_value *value) | |
c906108c SS |
1405 | { |
1406 | struct axs_value value1; | |
1407 | /* We don't want to turn this into an rvalue, so no conversions | |
1408 | here. */ | |
1409 | gen_expr (pc, ax, &value1); | |
1410 | if (value1.kind != axs_lvalue_memory) | |
3d263c1d | 1411 | error (_("Left operand of `@' must be an object in memory.")); |
c906108c SS |
1412 | |
1413 | /* Evaluate the length; it had better be a constant. */ | |
1414 | { | |
1415 | struct value *v = const_expr (pc); | |
1416 | int length; | |
1417 | ||
c5aa993b | 1418 | if (!v) |
3d263c1d | 1419 | error (_("Right operand of `@' must be a constant, in agent expressions.")); |
04624583 | 1420 | if (TYPE_CODE (value_type (v)) != TYPE_CODE_INT) |
3d263c1d | 1421 | error (_("Right operand of `@' must be an integer.")); |
c906108c SS |
1422 | length = value_as_long (v); |
1423 | if (length <= 0) | |
3d263c1d | 1424 | error (_("Right operand of `@' must be positive.")); |
c906108c SS |
1425 | |
1426 | /* The top of the stack is already the address of the object, so | |
1427 | all we need to do is frob the type of the lvalue. */ | |
1428 | { | |
1429 | /* FIXME-type-allocation: need a way to free this type when we are | |
c5aa993b | 1430 | done with it. */ |
c906108c | 1431 | struct type *range |
c5aa993b | 1432 | = create_range_type (0, builtin_type_int, 0, length - 1); |
c906108c SS |
1433 | struct type *array = create_array_type (0, value1.type, range); |
1434 | ||
1435 | value->kind = axs_lvalue_memory; | |
1436 | value->type = array; | |
1437 | } | |
1438 | } | |
1439 | } | |
1440 | ||
1441 | ||
1442 | /* Emit code for the `sizeof' operator. | |
1443 | *PC should point at the start of the operand expression; we advance it | |
1444 | to the first instruction after the operand. */ | |
1445 | static void | |
fba45db2 KB |
1446 | gen_sizeof (union exp_element **pc, struct agent_expr *ax, |
1447 | struct axs_value *value) | |
c906108c SS |
1448 | { |
1449 | /* We don't care about the value of the operand expression; we only | |
1450 | care about its type. However, in the current arrangement, the | |
1451 | only way to find an expression's type is to generate code for it. | |
1452 | So we generate code for the operand, and then throw it away, | |
1453 | replacing it with code that simply pushes its size. */ | |
1454 | int start = ax->len; | |
1455 | gen_expr (pc, ax, value); | |
1456 | ||
1457 | /* Throw away the code we just generated. */ | |
1458 | ax->len = start; | |
c5aa993b | 1459 | |
c906108c SS |
1460 | ax_const_l (ax, TYPE_LENGTH (value->type)); |
1461 | value->kind = axs_rvalue; | |
1462 | value->type = builtin_type_int; | |
1463 | } | |
c906108c | 1464 | \f |
c5aa993b | 1465 | |
c906108c SS |
1466 | /* Generating bytecode from GDB expressions: general recursive thingy */ |
1467 | ||
3d263c1d | 1468 | /* XXX: i18n */ |
c906108c SS |
1469 | /* A gen_expr function written by a Gen-X'er guy. |
1470 | Append code for the subexpression of EXPR starting at *POS_P to AX. */ | |
1471 | static void | |
fba45db2 KB |
1472 | gen_expr (union exp_element **pc, struct agent_expr *ax, |
1473 | struct axs_value *value) | |
c906108c SS |
1474 | { |
1475 | /* Used to hold the descriptions of operand expressions. */ | |
1476 | struct axs_value value1, value2; | |
1477 | enum exp_opcode op = (*pc)[0].opcode; | |
1478 | ||
1479 | /* If we're looking at a constant expression, just push its value. */ | |
1480 | { | |
1481 | struct value *v = maybe_const_expr (pc); | |
c5aa993b | 1482 | |
c906108c SS |
1483 | if (v) |
1484 | { | |
1485 | ax_const_l (ax, value_as_long (v)); | |
1486 | value->kind = axs_rvalue; | |
df407dfe | 1487 | value->type = check_typedef (value_type (v)); |
c906108c SS |
1488 | return; |
1489 | } | |
1490 | } | |
1491 | ||
1492 | /* Otherwise, go ahead and generate code for it. */ | |
1493 | switch (op) | |
1494 | { | |
1495 | /* Binary arithmetic operators. */ | |
1496 | case BINOP_ADD: | |
1497 | case BINOP_SUB: | |
1498 | case BINOP_MUL: | |
1499 | case BINOP_DIV: | |
1500 | case BINOP_REM: | |
1501 | case BINOP_SUBSCRIPT: | |
1502 | case BINOP_BITWISE_AND: | |
1503 | case BINOP_BITWISE_IOR: | |
1504 | case BINOP_BITWISE_XOR: | |
1505 | (*pc)++; | |
1506 | gen_expr (pc, ax, &value1); | |
1507 | gen_usual_unary (ax, &value1); | |
1508 | gen_expr (pc, ax, &value2); | |
1509 | gen_usual_unary (ax, &value2); | |
1510 | gen_usual_arithmetic (ax, &value1, &value2); | |
1511 | switch (op) | |
1512 | { | |
1513 | case BINOP_ADD: | |
1514 | gen_add (ax, value, &value1, &value2, "addition"); | |
1515 | break; | |
1516 | case BINOP_SUB: | |
1517 | gen_sub (ax, value, &value1, &value2); | |
1518 | break; | |
1519 | case BINOP_MUL: | |
1520 | gen_binop (ax, value, &value1, &value2, | |
1521 | aop_mul, aop_mul, 1, "multiplication"); | |
1522 | break; | |
1523 | case BINOP_DIV: | |
1524 | gen_binop (ax, value, &value1, &value2, | |
1525 | aop_div_signed, aop_div_unsigned, 1, "division"); | |
1526 | break; | |
1527 | case BINOP_REM: | |
1528 | gen_binop (ax, value, &value1, &value2, | |
1529 | aop_rem_signed, aop_rem_unsigned, 1, "remainder"); | |
1530 | break; | |
1531 | case BINOP_SUBSCRIPT: | |
1532 | gen_add (ax, value, &value1, &value2, "array subscripting"); | |
1533 | if (TYPE_CODE (value->type) != TYPE_CODE_PTR) | |
3d263c1d | 1534 | error (_("Invalid combination of types in array subscripting.")); |
c906108c SS |
1535 | gen_deref (ax, value); |
1536 | break; | |
1537 | case BINOP_BITWISE_AND: | |
1538 | gen_binop (ax, value, &value1, &value2, | |
1539 | aop_bit_and, aop_bit_and, 0, "bitwise and"); | |
1540 | break; | |
1541 | ||
1542 | case BINOP_BITWISE_IOR: | |
1543 | gen_binop (ax, value, &value1, &value2, | |
1544 | aop_bit_or, aop_bit_or, 0, "bitwise or"); | |
1545 | break; | |
1546 | ||
1547 | case BINOP_BITWISE_XOR: | |
1548 | gen_binop (ax, value, &value1, &value2, | |
1549 | aop_bit_xor, aop_bit_xor, 0, "bitwise exclusive-or"); | |
1550 | break; | |
1551 | ||
1552 | default: | |
1553 | /* We should only list operators in the outer case statement | |
c5aa993b | 1554 | that we actually handle in the inner case statement. */ |
8e65ff28 | 1555 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1556 | _("gen_expr: op case sets don't match")); |
c906108c SS |
1557 | } |
1558 | break; | |
1559 | ||
1560 | /* Note that we need to be a little subtle about generating code | |
c5aa993b JM |
1561 | for comma. In C, we can do some optimizations here because |
1562 | we know the left operand is only being evaluated for effect. | |
1563 | However, if the tracing kludge is in effect, then we always | |
1564 | need to evaluate the left hand side fully, so that all the | |
1565 | variables it mentions get traced. */ | |
c906108c SS |
1566 | case BINOP_COMMA: |
1567 | (*pc)++; | |
1568 | gen_expr (pc, ax, &value1); | |
1569 | /* Don't just dispose of the left operand. We might be tracing, | |
c5aa993b JM |
1570 | in which case we want to emit code to trace it if it's an |
1571 | lvalue. */ | |
c906108c SS |
1572 | gen_traced_pop (ax, &value1); |
1573 | gen_expr (pc, ax, value); | |
1574 | /* It's the consumer's responsibility to trace the right operand. */ | |
1575 | break; | |
c5aa993b | 1576 | |
c906108c SS |
1577 | case OP_LONG: /* some integer constant */ |
1578 | { | |
1579 | struct type *type = (*pc)[1].type; | |
1580 | LONGEST k = (*pc)[2].longconst; | |
1581 | (*pc) += 4; | |
1582 | gen_int_literal (ax, value, k, type); | |
1583 | } | |
c5aa993b | 1584 | break; |
c906108c SS |
1585 | |
1586 | case OP_VAR_VALUE: | |
1587 | gen_var_ref (ax, value, (*pc)[2].symbol); | |
1588 | (*pc) += 4; | |
1589 | break; | |
1590 | ||
1591 | case OP_REGISTER: | |
1592 | { | |
67f3407f DJ |
1593 | const char *name = &(*pc)[2].string; |
1594 | int reg; | |
1595 | (*pc) += 4 + BYTES_TO_EXP_ELEM ((*pc)[1].longconst + 1); | |
029a67e4 UW |
1596 | reg = user_reg_map_name_to_regnum (current_gdbarch, |
1597 | name, strlen (name)); | |
67f3407f DJ |
1598 | if (reg == -1) |
1599 | internal_error (__FILE__, __LINE__, | |
1600 | _("Register $%s not available"), name); | |
02e4669d JB |
1601 | if (reg >= gdbarch_num_regs (current_gdbarch)) |
1602 | error (_("'%s' is a pseudo-register; " | |
1603 | "GDB cannot yet trace pseudoregister contents."), | |
1604 | name); | |
c906108c SS |
1605 | value->kind = axs_lvalue_register; |
1606 | value->u.reg = reg; | |
7b83296f | 1607 | value->type = register_type (current_gdbarch, reg); |
c906108c | 1608 | } |
c5aa993b | 1609 | break; |
c906108c SS |
1610 | |
1611 | case OP_INTERNALVAR: | |
3d263c1d | 1612 | error (_("GDB agent expressions cannot use convenience variables.")); |
c906108c | 1613 | |
c5aa993b | 1614 | /* Weirdo operator: see comments for gen_repeat for details. */ |
c906108c SS |
1615 | case BINOP_REPEAT: |
1616 | /* Note that gen_repeat handles its own argument evaluation. */ | |
1617 | (*pc)++; | |
1618 | gen_repeat (pc, ax, value); | |
1619 | break; | |
1620 | ||
1621 | case UNOP_CAST: | |
1622 | { | |
1623 | struct type *type = (*pc)[1].type; | |
1624 | (*pc) += 3; | |
1625 | gen_expr (pc, ax, value); | |
1626 | gen_cast (ax, value, type); | |
1627 | } | |
c5aa993b | 1628 | break; |
c906108c SS |
1629 | |
1630 | case UNOP_MEMVAL: | |
1631 | { | |
1632 | struct type *type = check_typedef ((*pc)[1].type); | |
1633 | (*pc) += 3; | |
1634 | gen_expr (pc, ax, value); | |
1635 | /* I'm not sure I understand UNOP_MEMVAL entirely. I think | |
1636 | it's just a hack for dealing with minsyms; you take some | |
1637 | integer constant, pretend it's the address of an lvalue of | |
1638 | the given type, and dereference it. */ | |
1639 | if (value->kind != axs_rvalue) | |
1640 | /* This would be weird. */ | |
8e65ff28 | 1641 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1642 | _("gen_expr: OP_MEMVAL operand isn't an rvalue???")); |
c906108c SS |
1643 | value->type = type; |
1644 | value->kind = axs_lvalue_memory; | |
1645 | } | |
c5aa993b | 1646 | break; |
c906108c | 1647 | |
36e9969c NS |
1648 | case UNOP_PLUS: |
1649 | (*pc)++; | |
1650 | /* + FOO is equivalent to 0 + FOO, which can be optimized. */ | |
1651 | gen_expr (pc, ax, value); | |
1652 | gen_usual_unary (ax, value); | |
1653 | break; | |
1654 | ||
c906108c SS |
1655 | case UNOP_NEG: |
1656 | (*pc)++; | |
1657 | /* -FOO is equivalent to 0 - FOO. */ | |
1658 | gen_int_literal (ax, &value1, (LONGEST) 0, builtin_type_int); | |
c5aa993b | 1659 | gen_usual_unary (ax, &value1); /* shouldn't do much */ |
c906108c SS |
1660 | gen_expr (pc, ax, &value2); |
1661 | gen_usual_unary (ax, &value2); | |
1662 | gen_usual_arithmetic (ax, &value1, &value2); | |
1663 | gen_sub (ax, value, &value1, &value2); | |
1664 | break; | |
1665 | ||
1666 | case UNOP_LOGICAL_NOT: | |
1667 | (*pc)++; | |
1668 | gen_expr (pc, ax, value); | |
1669 | gen_logical_not (ax, value); | |
1670 | break; | |
1671 | ||
1672 | case UNOP_COMPLEMENT: | |
1673 | (*pc)++; | |
1674 | gen_expr (pc, ax, value); | |
1675 | gen_complement (ax, value); | |
1676 | break; | |
1677 | ||
1678 | case UNOP_IND: | |
1679 | (*pc)++; | |
1680 | gen_expr (pc, ax, value); | |
1681 | gen_usual_unary (ax, value); | |
1682 | if (TYPE_CODE (value->type) != TYPE_CODE_PTR) | |
3d263c1d | 1683 | error (_("Argument of unary `*' is not a pointer.")); |
c906108c SS |
1684 | gen_deref (ax, value); |
1685 | break; | |
1686 | ||
1687 | case UNOP_ADDR: | |
1688 | (*pc)++; | |
1689 | gen_expr (pc, ax, value); | |
1690 | gen_address_of (ax, value); | |
1691 | break; | |
1692 | ||
1693 | case UNOP_SIZEOF: | |
1694 | (*pc)++; | |
1695 | /* Notice that gen_sizeof handles its own operand, unlike most | |
c5aa993b JM |
1696 | of the other unary operator functions. This is because we |
1697 | have to throw away the code we generate. */ | |
c906108c SS |
1698 | gen_sizeof (pc, ax, value); |
1699 | break; | |
1700 | ||
1701 | case STRUCTOP_STRUCT: | |
1702 | case STRUCTOP_PTR: | |
1703 | { | |
1704 | int length = (*pc)[1].longconst; | |
1705 | char *name = &(*pc)[2].string; | |
1706 | ||
1707 | (*pc) += 4 + BYTES_TO_EXP_ELEM (length + 1); | |
1708 | gen_expr (pc, ax, value); | |
1709 | if (op == STRUCTOP_STRUCT) | |
1710 | gen_struct_ref (ax, value, name, ".", "structure or union"); | |
1711 | else if (op == STRUCTOP_PTR) | |
1712 | gen_struct_ref (ax, value, name, "->", | |
1713 | "pointer to a structure or union"); | |
1714 | else | |
1715 | /* If this `if' chain doesn't handle it, then the case list | |
c5aa993b | 1716 | shouldn't mention it, and we shouldn't be here. */ |
8e65ff28 | 1717 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1718 | _("gen_expr: unhandled struct case")); |
c906108c | 1719 | } |
c5aa993b | 1720 | break; |
c906108c SS |
1721 | |
1722 | case OP_TYPE: | |
3d263c1d | 1723 | error (_("Attempt to use a type name as an expression.")); |
c906108c SS |
1724 | |
1725 | default: | |
3d263c1d | 1726 | error (_("Unsupported operator in expression.")); |
c906108c SS |
1727 | } |
1728 | } | |
c906108c | 1729 | \f |
c5aa993b JM |
1730 | |
1731 | ||
c906108c SS |
1732 | /* Generating bytecode from GDB expressions: driver */ |
1733 | ||
c906108c SS |
1734 | /* Given a GDB expression EXPR, return bytecode to trace its value. |
1735 | The result will use the `trace' and `trace_quick' bytecodes to | |
1736 | record the value of all memory touched by the expression. The | |
1737 | caller can then use the ax_reqs function to discover which | |
1738 | registers it relies upon. */ | |
1739 | struct agent_expr * | |
fba45db2 | 1740 | gen_trace_for_expr (CORE_ADDR scope, struct expression *expr) |
c906108c SS |
1741 | { |
1742 | struct cleanup *old_chain = 0; | |
1743 | struct agent_expr *ax = new_agent_expr (scope); | |
1744 | union exp_element *pc; | |
1745 | struct axs_value value; | |
1746 | ||
f23d52e0 | 1747 | old_chain = make_cleanup_free_agent_expr (ax); |
c906108c SS |
1748 | |
1749 | pc = expr->elts; | |
1750 | trace_kludge = 1; | |
1751 | gen_expr (&pc, ax, &value); | |
1752 | ||
1753 | /* Make sure we record the final object, and get rid of it. */ | |
1754 | gen_traced_pop (ax, &value); | |
1755 | ||
1756 | /* Oh, and terminate. */ | |
1757 | ax_simple (ax, aop_end); | |
1758 | ||
1759 | /* We have successfully built the agent expr, so cancel the cleanup | |
1760 | request. If we add more cleanups that we always want done, this | |
1761 | will have to get more complicated. */ | |
1762 | discard_cleanups (old_chain); | |
1763 | return ax; | |
1764 | } | |
c906108c SS |
1765 | |
1766 | static void | |
fba45db2 | 1767 | agent_command (char *exp, int from_tty) |
c906108c SS |
1768 | { |
1769 | struct cleanup *old_chain = 0; | |
1770 | struct expression *expr; | |
1771 | struct agent_expr *agent; | |
6426a772 | 1772 | struct frame_info *fi = get_current_frame (); /* need current scope */ |
c906108c SS |
1773 | |
1774 | /* We don't deal with overlay debugging at the moment. We need to | |
1775 | think more carefully about this. If you copy this code into | |
1776 | another command, change the error message; the user shouldn't | |
1777 | have to know anything about agent expressions. */ | |
1778 | if (overlay_debugging) | |
3d263c1d | 1779 | error (_("GDB can't do agent expression translation with overlays.")); |
c906108c SS |
1780 | |
1781 | if (exp == 0) | |
3d263c1d | 1782 | error_no_arg (_("expression to translate")); |
c5aa993b | 1783 | |
c906108c | 1784 | expr = parse_expression (exp); |
c13c43fd | 1785 | old_chain = make_cleanup (free_current_contents, &expr); |
bdd78e62 | 1786 | agent = gen_trace_for_expr (get_frame_pc (fi), expr); |
f23d52e0 | 1787 | make_cleanup_free_agent_expr (agent); |
c906108c | 1788 | ax_print (gdb_stdout, agent); |
085dd6e6 JM |
1789 | |
1790 | /* It would be nice to call ax_reqs here to gather some general info | |
1791 | about the expression, and then print out the result. */ | |
c906108c SS |
1792 | |
1793 | do_cleanups (old_chain); | |
1794 | dont_repeat (); | |
1795 | } | |
c906108c | 1796 | \f |
c5aa993b | 1797 | |
c906108c SS |
1798 | /* Initialization code. */ |
1799 | ||
a14ed312 | 1800 | void _initialize_ax_gdb (void); |
c906108c | 1801 | void |
fba45db2 | 1802 | _initialize_ax_gdb (void) |
c906108c | 1803 | { |
c906108c | 1804 | add_cmd ("agent", class_maintenance, agent_command, |
3d263c1d | 1805 | _("Translate an expression into remote agent bytecode."), |
c906108c SS |
1806 | &maintenancelist); |
1807 | } |