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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" |
c906108c | 36 | |
6426a772 JM |
37 | /* To make sense of this file, you should read doc/agentexpr.texi. |
38 | Then look at the types and enums in ax-gdb.h. For the code itself, | |
39 | look at gen_expr, towards the bottom; that's the main function that | |
40 | looks at the GDB expressions and calls everything else to generate | |
41 | code. | |
c906108c SS |
42 | |
43 | I'm beginning to wonder whether it wouldn't be nicer to internally | |
44 | generate trees, with types, and then spit out the bytecode in | |
45 | linear form afterwards; we could generate fewer `swap', `ext', and | |
46 | `zero_ext' bytecodes that way; it would make good constant folding | |
47 | easier, too. But at the moment, I think we should be willing to | |
48 | pay for the simplicity of this code with less-than-optimal bytecode | |
49 | strings. | |
50 | ||
c5aa993b JM |
51 | Remember, "GBD" stands for "Great Britain, Dammit!" So be careful. */ |
52 | \f | |
c906108c SS |
53 | |
54 | ||
c906108c SS |
55 | /* Prototypes for local functions. */ |
56 | ||
57 | /* There's a standard order to the arguments of these functions: | |
58 | union exp_element ** --- pointer into expression | |
59 | struct agent_expr * --- agent expression buffer to generate code into | |
60 | struct axs_value * --- describes value left on top of stack */ | |
c5aa993b | 61 | |
a14ed312 KB |
62 | static struct value *const_var_ref (struct symbol *var); |
63 | static struct value *const_expr (union exp_element **pc); | |
64 | static struct value *maybe_const_expr (union exp_element **pc); | |
65 | ||
66 | static void gen_traced_pop (struct agent_expr *, struct axs_value *); | |
67 | ||
68 | static void gen_sign_extend (struct agent_expr *, struct type *); | |
69 | static void gen_extend (struct agent_expr *, struct type *); | |
70 | static void gen_fetch (struct agent_expr *, struct type *); | |
71 | static void gen_left_shift (struct agent_expr *, int); | |
72 | ||
73 | ||
74 | static void gen_frame_args_address (struct agent_expr *); | |
75 | static void gen_frame_locals_address (struct agent_expr *); | |
76 | static void gen_offset (struct agent_expr *ax, int offset); | |
77 | static void gen_sym_offset (struct agent_expr *, struct symbol *); | |
78 | static void gen_var_ref (struct agent_expr *ax, | |
79 | struct axs_value *value, struct symbol *var); | |
80 | ||
81 | ||
82 | static void gen_int_literal (struct agent_expr *ax, | |
83 | struct axs_value *value, | |
84 | LONGEST k, struct type *type); | |
85 | ||
86 | ||
87 | static void require_rvalue (struct agent_expr *ax, struct axs_value *value); | |
88 | static void gen_usual_unary (struct agent_expr *ax, struct axs_value *value); | |
89 | static int type_wider_than (struct type *type1, struct type *type2); | |
90 | static struct type *max_type (struct type *type1, struct type *type2); | |
91 | static void gen_conversion (struct agent_expr *ax, | |
92 | struct type *from, struct type *to); | |
93 | static int is_nontrivial_conversion (struct type *from, struct type *to); | |
94 | static void gen_usual_arithmetic (struct agent_expr *ax, | |
95 | struct axs_value *value1, | |
96 | struct axs_value *value2); | |
97 | static void gen_integral_promotions (struct agent_expr *ax, | |
98 | struct axs_value *value); | |
99 | static void gen_cast (struct agent_expr *ax, | |
100 | struct axs_value *value, struct type *type); | |
101 | static void gen_scale (struct agent_expr *ax, | |
102 | enum agent_op op, struct type *type); | |
103 | static void gen_add (struct agent_expr *ax, | |
104 | struct axs_value *value, | |
105 | struct axs_value *value1, | |
106 | struct axs_value *value2, char *name); | |
107 | static void gen_sub (struct agent_expr *ax, | |
108 | struct axs_value *value, | |
109 | struct axs_value *value1, struct axs_value *value2); | |
110 | static void gen_binop (struct agent_expr *ax, | |
111 | struct axs_value *value, | |
112 | struct axs_value *value1, | |
113 | struct axs_value *value2, | |
114 | enum agent_op op, | |
115 | enum agent_op op_unsigned, int may_carry, char *name); | |
116 | static void gen_logical_not (struct agent_expr *ax, struct axs_value *value); | |
117 | static void gen_complement (struct agent_expr *ax, struct axs_value *value); | |
118 | static void gen_deref (struct agent_expr *, struct axs_value *); | |
119 | static void gen_address_of (struct agent_expr *, struct axs_value *); | |
120 | static int find_field (struct type *type, char *name); | |
121 | static void gen_bitfield_ref (struct agent_expr *ax, | |
122 | struct axs_value *value, | |
123 | struct type *type, int start, int end); | |
124 | static void gen_struct_ref (struct agent_expr *ax, | |
125 | struct axs_value *value, | |
126 | char *field, | |
127 | char *operator_name, char *operand_name); | |
128 | static void gen_repeat (union exp_element **pc, | |
129 | struct agent_expr *ax, struct axs_value *value); | |
130 | static void gen_sizeof (union exp_element **pc, | |
131 | struct agent_expr *ax, struct axs_value *value); | |
132 | static void gen_expr (union exp_element **pc, | |
133 | struct agent_expr *ax, struct axs_value *value); | |
c5aa993b | 134 | |
a14ed312 | 135 | static void agent_command (char *exp, int from_tty); |
c906108c | 136 | \f |
c5aa993b | 137 | |
c906108c SS |
138 | /* Detecting constant expressions. */ |
139 | ||
140 | /* If the variable reference at *PC is a constant, return its value. | |
141 | Otherwise, return zero. | |
142 | ||
143 | Hey, Wally! How can a variable reference be a constant? | |
144 | ||
145 | Well, Beav, this function really handles the OP_VAR_VALUE operator, | |
146 | not specifically variable references. GDB uses OP_VAR_VALUE to | |
147 | refer to any kind of symbolic reference: function names, enum | |
148 | elements, and goto labels are all handled through the OP_VAR_VALUE | |
149 | operator, even though they're constants. It makes sense given the | |
150 | situation. | |
151 | ||
152 | Gee, Wally, don'cha wonder sometimes if data representations that | |
153 | subvert commonly accepted definitions of terms in favor of heavily | |
154 | context-specific interpretations are really just a tool of the | |
155 | programming hegemony to preserve their power and exclude the | |
156 | proletariat? */ | |
157 | ||
158 | static struct value * | |
fba45db2 | 159 | const_var_ref (struct symbol *var) |
c906108c SS |
160 | { |
161 | struct type *type = SYMBOL_TYPE (var); | |
162 | ||
163 | switch (SYMBOL_CLASS (var)) | |
164 | { | |
165 | case LOC_CONST: | |
166 | return value_from_longest (type, (LONGEST) SYMBOL_VALUE (var)); | |
167 | ||
168 | case LOC_LABEL: | |
4478b372 | 169 | return value_from_pointer (type, (CORE_ADDR) SYMBOL_VALUE_ADDRESS (var)); |
c906108c SS |
170 | |
171 | default: | |
172 | return 0; | |
173 | } | |
174 | } | |
175 | ||
176 | ||
177 | /* If the expression starting at *PC has a constant value, return it. | |
178 | Otherwise, return zero. If we return a value, then *PC will be | |
179 | advanced to the end of it. If we return zero, *PC could be | |
180 | anywhere. */ | |
181 | static struct value * | |
fba45db2 | 182 | const_expr (union exp_element **pc) |
c906108c SS |
183 | { |
184 | enum exp_opcode op = (*pc)->opcode; | |
185 | struct value *v1; | |
186 | ||
187 | switch (op) | |
188 | { | |
189 | case OP_LONG: | |
190 | { | |
191 | struct type *type = (*pc)[1].type; | |
192 | LONGEST k = (*pc)[2].longconst; | |
193 | (*pc) += 4; | |
194 | return value_from_longest (type, k); | |
195 | } | |
196 | ||
197 | case OP_VAR_VALUE: | |
198 | { | |
199 | struct value *v = const_var_ref ((*pc)[2].symbol); | |
200 | (*pc) += 4; | |
201 | return v; | |
202 | } | |
203 | ||
c5aa993b | 204 | /* We could add more operators in here. */ |
c906108c SS |
205 | |
206 | case UNOP_NEG: | |
207 | (*pc)++; | |
208 | v1 = const_expr (pc); | |
209 | if (v1) | |
210 | return value_neg (v1); | |
211 | else | |
212 | return 0; | |
213 | ||
214 | default: | |
215 | return 0; | |
216 | } | |
217 | } | |
218 | ||
219 | ||
220 | /* Like const_expr, but guarantee also that *PC is undisturbed if the | |
221 | expression is not constant. */ | |
222 | static struct value * | |
fba45db2 | 223 | maybe_const_expr (union exp_element **pc) |
c906108c SS |
224 | { |
225 | union exp_element *tentative_pc = *pc; | |
226 | struct value *v = const_expr (&tentative_pc); | |
227 | ||
228 | /* If we got a value, then update the real PC. */ | |
229 | if (v) | |
230 | *pc = tentative_pc; | |
c5aa993b | 231 | |
c906108c SS |
232 | return v; |
233 | } | |
c906108c | 234 | \f |
c5aa993b | 235 | |
c906108c SS |
236 | /* Generating bytecode from GDB expressions: general assumptions */ |
237 | ||
238 | /* Here are a few general assumptions made throughout the code; if you | |
239 | want to make a change that contradicts one of these, then you'd | |
240 | better scan things pretty thoroughly. | |
241 | ||
242 | - We assume that all values occupy one stack element. For example, | |
c5aa993b JM |
243 | sometimes we'll swap to get at the left argument to a binary |
244 | operator. If we decide that void values should occupy no stack | |
245 | elements, or that synthetic arrays (whose size is determined at | |
246 | run time, created by the `@' operator) should occupy two stack | |
247 | elements (address and length), then this will cause trouble. | |
c906108c SS |
248 | |
249 | - We assume the stack elements are infinitely wide, and that we | |
c5aa993b JM |
250 | don't have to worry what happens if the user requests an |
251 | operation that is wider than the actual interpreter's stack. | |
252 | That is, it's up to the interpreter to handle directly all the | |
253 | integer widths the user has access to. (Woe betide the language | |
254 | with bignums!) | |
c906108c SS |
255 | |
256 | - We don't support side effects. Thus, we don't have to worry about | |
c5aa993b | 257 | GCC's generalized lvalues, function calls, etc. |
c906108c SS |
258 | |
259 | - We don't support floating point. Many places where we switch on | |
c5aa993b JM |
260 | some type don't bother to include cases for floating point; there |
261 | may be even more subtle ways this assumption exists. For | |
262 | example, the arguments to % must be integers. | |
c906108c SS |
263 | |
264 | - We assume all subexpressions have a static, unchanging type. If | |
c5aa993b JM |
265 | we tried to support convenience variables, this would be a |
266 | problem. | |
c906108c SS |
267 | |
268 | - All values on the stack should always be fully zero- or | |
c5aa993b JM |
269 | sign-extended. |
270 | ||
271 | (I wasn't sure whether to choose this or its opposite --- that | |
272 | only addresses are assumed extended --- but it turns out that | |
273 | neither convention completely eliminates spurious extend | |
274 | operations (if everything is always extended, then you have to | |
275 | extend after add, because it could overflow; if nothing is | |
276 | extended, then you end up producing extends whenever you change | |
277 | sizes), and this is simpler.) */ | |
c906108c | 278 | \f |
c5aa993b | 279 | |
c906108c SS |
280 | /* Generating bytecode from GDB expressions: the `trace' kludge */ |
281 | ||
282 | /* The compiler in this file is a general-purpose mechanism for | |
283 | translating GDB expressions into bytecode. One ought to be able to | |
284 | find a million and one uses for it. | |
285 | ||
286 | However, at the moment it is HOPELESSLY BRAIN-DAMAGED for the sake | |
287 | of expediency. Let he who is without sin cast the first stone. | |
288 | ||
289 | For the data tracing facility, we need to insert `trace' bytecodes | |
290 | before each data fetch; this records all the memory that the | |
291 | expression touches in the course of evaluation, so that memory will | |
292 | be available when the user later tries to evaluate the expression | |
293 | in GDB. | |
294 | ||
295 | This should be done (I think) in a post-processing pass, that walks | |
296 | an arbitrary agent expression and inserts `trace' operations at the | |
297 | appropriate points. But it's much faster to just hack them | |
298 | directly into the code. And since we're in a crunch, that's what | |
299 | I've done. | |
300 | ||
301 | Setting the flag trace_kludge to non-zero enables the code that | |
302 | emits the trace bytecodes at the appropriate points. */ | |
303 | static int trace_kludge; | |
304 | ||
305 | /* Trace the lvalue on the stack, if it needs it. In either case, pop | |
306 | the value. Useful on the left side of a comma, and at the end of | |
307 | an expression being used for tracing. */ | |
308 | static void | |
fba45db2 | 309 | gen_traced_pop (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
310 | { |
311 | if (trace_kludge) | |
312 | switch (value->kind) | |
313 | { | |
314 | case axs_rvalue: | |
315 | /* We don't trace rvalues, just the lvalues necessary to | |
c5aa993b | 316 | produce them. So just dispose of this value. */ |
c906108c SS |
317 | ax_simple (ax, aop_pop); |
318 | break; | |
319 | ||
320 | case axs_lvalue_memory: | |
321 | { | |
648027cc | 322 | int length = TYPE_LENGTH (check_typedef (value->type)); |
c906108c SS |
323 | |
324 | /* There's no point in trying to use a trace_quick bytecode | |
325 | here, since "trace_quick SIZE pop" is three bytes, whereas | |
326 | "const8 SIZE trace" is also three bytes, does the same | |
327 | thing, and the simplest code which generates that will also | |
328 | work correctly for objects with large sizes. */ | |
329 | ax_const_l (ax, length); | |
330 | ax_simple (ax, aop_trace); | |
331 | } | |
c5aa993b | 332 | break; |
c906108c SS |
333 | |
334 | case axs_lvalue_register: | |
335 | /* We need to mention the register somewhere in the bytecode, | |
336 | so ax_reqs will pick it up and add it to the mask of | |
337 | registers used. */ | |
338 | ax_reg (ax, value->u.reg); | |
339 | ax_simple (ax, aop_pop); | |
340 | break; | |
341 | } | |
342 | else | |
343 | /* If we're not tracing, just pop the value. */ | |
344 | ax_simple (ax, aop_pop); | |
345 | } | |
c5aa993b | 346 | \f |
c906108c SS |
347 | |
348 | ||
c906108c SS |
349 | /* Generating bytecode from GDB expressions: helper functions */ |
350 | ||
351 | /* Assume that the lower bits of the top of the stack is a value of | |
352 | type TYPE, and the upper bits are zero. Sign-extend if necessary. */ | |
353 | static void | |
fba45db2 | 354 | gen_sign_extend (struct agent_expr *ax, struct type *type) |
c906108c SS |
355 | { |
356 | /* Do we need to sign-extend this? */ | |
c5aa993b | 357 | if (!TYPE_UNSIGNED (type)) |
0004e5a2 | 358 | ax_ext (ax, TYPE_LENGTH (type) * TARGET_CHAR_BIT); |
c906108c SS |
359 | } |
360 | ||
361 | ||
362 | /* Assume the lower bits of the top of the stack hold a value of type | |
363 | TYPE, and the upper bits are garbage. Sign-extend or truncate as | |
364 | needed. */ | |
365 | static void | |
fba45db2 | 366 | gen_extend (struct agent_expr *ax, struct type *type) |
c906108c | 367 | { |
0004e5a2 | 368 | int bits = TYPE_LENGTH (type) * TARGET_CHAR_BIT; |
c906108c SS |
369 | /* I just had to. */ |
370 | ((TYPE_UNSIGNED (type) ? ax_zero_ext : ax_ext) (ax, bits)); | |
371 | } | |
372 | ||
373 | ||
374 | /* Assume that the top of the stack contains a value of type "pointer | |
375 | to TYPE"; generate code to fetch its value. Note that TYPE is the | |
376 | target type, not the pointer type. */ | |
377 | static void | |
fba45db2 | 378 | gen_fetch (struct agent_expr *ax, struct type *type) |
c906108c SS |
379 | { |
380 | if (trace_kludge) | |
381 | { | |
382 | /* Record the area of memory we're about to fetch. */ | |
383 | ax_trace_quick (ax, TYPE_LENGTH (type)); | |
384 | } | |
385 | ||
0004e5a2 | 386 | switch (TYPE_CODE (type)) |
c906108c SS |
387 | { |
388 | case TYPE_CODE_PTR: | |
389 | case TYPE_CODE_ENUM: | |
390 | case TYPE_CODE_INT: | |
391 | case TYPE_CODE_CHAR: | |
392 | /* It's a scalar value, so we know how to dereference it. How | |
393 | many bytes long is it? */ | |
0004e5a2 | 394 | switch (TYPE_LENGTH (type)) |
c906108c | 395 | { |
c5aa993b JM |
396 | case 8 / TARGET_CHAR_BIT: |
397 | ax_simple (ax, aop_ref8); | |
398 | break; | |
399 | case 16 / TARGET_CHAR_BIT: | |
400 | ax_simple (ax, aop_ref16); | |
401 | break; | |
402 | case 32 / TARGET_CHAR_BIT: | |
403 | ax_simple (ax, aop_ref32); | |
404 | break; | |
405 | case 64 / TARGET_CHAR_BIT: | |
406 | ax_simple (ax, aop_ref64); | |
407 | break; | |
c906108c SS |
408 | |
409 | /* Either our caller shouldn't have asked us to dereference | |
410 | that pointer (other code's fault), or we're not | |
411 | implementing something we should be (this code's fault). | |
412 | In any case, it's a bug the user shouldn't see. */ | |
413 | default: | |
8e65ff28 | 414 | internal_error (__FILE__, __LINE__, |
3d263c1d | 415 | _("gen_fetch: strange size")); |
c906108c SS |
416 | } |
417 | ||
418 | gen_sign_extend (ax, type); | |
419 | break; | |
420 | ||
421 | default: | |
422 | /* Either our caller shouldn't have asked us to dereference that | |
c5aa993b JM |
423 | pointer (other code's fault), or we're not implementing |
424 | something we should be (this code's fault). In any case, | |
425 | it's a bug the user shouldn't see. */ | |
8e65ff28 | 426 | internal_error (__FILE__, __LINE__, |
3d263c1d | 427 | _("gen_fetch: bad type code")); |
c906108c SS |
428 | } |
429 | } | |
430 | ||
431 | ||
432 | /* Generate code to left shift the top of the stack by DISTANCE bits, or | |
433 | right shift it by -DISTANCE bits if DISTANCE < 0. This generates | |
434 | unsigned (logical) right shifts. */ | |
435 | static void | |
fba45db2 | 436 | gen_left_shift (struct agent_expr *ax, int distance) |
c906108c SS |
437 | { |
438 | if (distance > 0) | |
439 | { | |
440 | ax_const_l (ax, distance); | |
441 | ax_simple (ax, aop_lsh); | |
442 | } | |
443 | else if (distance < 0) | |
444 | { | |
445 | ax_const_l (ax, -distance); | |
446 | ax_simple (ax, aop_rsh_unsigned); | |
447 | } | |
448 | } | |
c5aa993b | 449 | \f |
c906108c SS |
450 | |
451 | ||
c906108c SS |
452 | /* Generating bytecode from GDB expressions: symbol references */ |
453 | ||
454 | /* Generate code to push the base address of the argument portion of | |
455 | the top stack frame. */ | |
456 | static void | |
fba45db2 | 457 | gen_frame_args_address (struct agent_expr *ax) |
c906108c | 458 | { |
39d4ef09 AC |
459 | int frame_reg; |
460 | LONGEST frame_offset; | |
c906108c | 461 | |
c7bb205c UW |
462 | gdbarch_virtual_frame_pointer (current_gdbarch, |
463 | ax->scope, &frame_reg, &frame_offset); | |
c5aa993b | 464 | ax_reg (ax, frame_reg); |
c906108c SS |
465 | gen_offset (ax, frame_offset); |
466 | } | |
467 | ||
468 | ||
469 | /* Generate code to push the base address of the locals portion of the | |
470 | top stack frame. */ | |
471 | static void | |
fba45db2 | 472 | gen_frame_locals_address (struct agent_expr *ax) |
c906108c | 473 | { |
39d4ef09 AC |
474 | int frame_reg; |
475 | LONGEST frame_offset; | |
c906108c | 476 | |
c7bb205c UW |
477 | gdbarch_virtual_frame_pointer (current_gdbarch, |
478 | ax->scope, &frame_reg, &frame_offset); | |
c5aa993b | 479 | ax_reg (ax, frame_reg); |
c906108c SS |
480 | gen_offset (ax, frame_offset); |
481 | } | |
482 | ||
483 | ||
484 | /* Generate code to add OFFSET to the top of the stack. Try to | |
485 | generate short and readable code. We use this for getting to | |
486 | variables on the stack, and structure members. If we were | |
487 | programming in ML, it would be clearer why these are the same | |
488 | thing. */ | |
489 | static void | |
fba45db2 | 490 | gen_offset (struct agent_expr *ax, int offset) |
c906108c SS |
491 | { |
492 | /* It would suffice to simply push the offset and add it, but this | |
493 | makes it easier to read positive and negative offsets in the | |
494 | bytecode. */ | |
495 | if (offset > 0) | |
496 | { | |
497 | ax_const_l (ax, offset); | |
498 | ax_simple (ax, aop_add); | |
499 | } | |
500 | else if (offset < 0) | |
501 | { | |
502 | ax_const_l (ax, -offset); | |
503 | ax_simple (ax, aop_sub); | |
504 | } | |
505 | } | |
506 | ||
507 | ||
508 | /* In many cases, a symbol's value is the offset from some other | |
509 | address (stack frame, base register, etc.) Generate code to add | |
510 | VAR's value to the top of the stack. */ | |
511 | static void | |
fba45db2 | 512 | gen_sym_offset (struct agent_expr *ax, struct symbol *var) |
c906108c SS |
513 | { |
514 | gen_offset (ax, SYMBOL_VALUE (var)); | |
515 | } | |
516 | ||
517 | ||
518 | /* Generate code for a variable reference to AX. The variable is the | |
519 | symbol VAR. Set VALUE to describe the result. */ | |
520 | ||
521 | static void | |
fba45db2 | 522 | gen_var_ref (struct agent_expr *ax, struct axs_value *value, struct symbol *var) |
c906108c SS |
523 | { |
524 | /* Dereference any typedefs. */ | |
525 | value->type = check_typedef (SYMBOL_TYPE (var)); | |
526 | ||
527 | /* I'm imitating the code in read_var_value. */ | |
528 | switch (SYMBOL_CLASS (var)) | |
529 | { | |
530 | case LOC_CONST: /* A constant, like an enum value. */ | |
531 | ax_const_l (ax, (LONGEST) SYMBOL_VALUE (var)); | |
532 | value->kind = axs_rvalue; | |
533 | break; | |
534 | ||
535 | case LOC_LABEL: /* A goto label, being used as a value. */ | |
536 | ax_const_l (ax, (LONGEST) SYMBOL_VALUE_ADDRESS (var)); | |
537 | value->kind = axs_rvalue; | |
538 | break; | |
539 | ||
540 | case LOC_CONST_BYTES: | |
8e65ff28 | 541 | internal_error (__FILE__, __LINE__, |
3d263c1d | 542 | _("gen_var_ref: LOC_CONST_BYTES symbols are not supported")); |
c906108c SS |
543 | |
544 | /* Variable at a fixed location in memory. Easy. */ | |
545 | case LOC_STATIC: | |
546 | /* Push the address of the variable. */ | |
547 | ax_const_l (ax, SYMBOL_VALUE_ADDRESS (var)); | |
548 | value->kind = axs_lvalue_memory; | |
549 | break; | |
550 | ||
551 | case LOC_ARG: /* var lives in argument area of frame */ | |
552 | gen_frame_args_address (ax); | |
553 | gen_sym_offset (ax, var); | |
554 | value->kind = axs_lvalue_memory; | |
555 | break; | |
556 | ||
557 | case LOC_REF_ARG: /* As above, but the frame slot really | |
558 | holds the address of the variable. */ | |
559 | gen_frame_args_address (ax); | |
560 | gen_sym_offset (ax, var); | |
561 | /* Don't assume any particular pointer size. */ | |
562 | gen_fetch (ax, lookup_pointer_type (builtin_type_void)); | |
563 | value->kind = axs_lvalue_memory; | |
564 | break; | |
565 | ||
566 | case LOC_LOCAL: /* var lives in locals area of frame */ | |
c906108c SS |
567 | gen_frame_locals_address (ax); |
568 | gen_sym_offset (ax, var); | |
569 | value->kind = axs_lvalue_memory; | |
570 | break; | |
571 | ||
c906108c | 572 | case LOC_TYPEDEF: |
3d263c1d | 573 | error (_("Cannot compute value of typedef `%s'."), |
de5ad195 | 574 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
575 | break; |
576 | ||
577 | case LOC_BLOCK: | |
578 | ax_const_l (ax, BLOCK_START (SYMBOL_BLOCK_VALUE (var))); | |
579 | value->kind = axs_rvalue; | |
580 | break; | |
581 | ||
582 | case LOC_REGISTER: | |
c906108c SS |
583 | /* Don't generate any code at all; in the process of treating |
584 | this as an lvalue or rvalue, the caller will generate the | |
585 | right code. */ | |
586 | value->kind = axs_lvalue_register; | |
587 | value->u.reg = SYMBOL_VALUE (var); | |
588 | break; | |
589 | ||
590 | /* A lot like LOC_REF_ARG, but the pointer lives directly in a | |
2a2d4dc3 AS |
591 | register, not on the stack. Simpler than LOC_REGISTER |
592 | because it's just like any other case where the thing | |
593 | has a real address. */ | |
c906108c SS |
594 | case LOC_REGPARM_ADDR: |
595 | ax_reg (ax, SYMBOL_VALUE (var)); | |
596 | value->kind = axs_lvalue_memory; | |
597 | break; | |
598 | ||
599 | case LOC_UNRESOLVED: | |
600 | { | |
c5aa993b | 601 | struct minimal_symbol *msym |
22abf04a | 602 | = lookup_minimal_symbol (DEPRECATED_SYMBOL_NAME (var), NULL, NULL); |
c5aa993b | 603 | if (!msym) |
3d263c1d | 604 | error (_("Couldn't resolve symbol `%s'."), SYMBOL_PRINT_NAME (var)); |
c5aa993b | 605 | |
c906108c SS |
606 | /* Push the address of the variable. */ |
607 | ax_const_l (ax, SYMBOL_VALUE_ADDRESS (msym)); | |
608 | value->kind = axs_lvalue_memory; | |
609 | } | |
c5aa993b | 610 | break; |
c906108c | 611 | |
a55cc764 | 612 | case LOC_COMPUTED: |
a67af2b9 AC |
613 | /* FIXME: cagney/2004-01-26: It should be possible to |
614 | unconditionally call the SYMBOL_OPS method when available. | |
d3efc286 | 615 | Unfortunately DWARF 2 stores the frame-base (instead of the |
a67af2b9 AC |
616 | function) location in a function's symbol. Oops! For the |
617 | moment enable this when/where applicable. */ | |
618 | SYMBOL_OPS (var)->tracepoint_var_ref (var, ax, value); | |
a55cc764 DJ |
619 | break; |
620 | ||
c906108c | 621 | case LOC_OPTIMIZED_OUT: |
3d263c1d | 622 | error (_("The variable `%s' has been optimized out."), |
de5ad195 | 623 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
624 | break; |
625 | ||
626 | default: | |
3d263c1d | 627 | error (_("Cannot find value of botched symbol `%s'."), |
de5ad195 | 628 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
629 | break; |
630 | } | |
631 | } | |
c5aa993b | 632 | \f |
c906108c SS |
633 | |
634 | ||
c906108c SS |
635 | /* Generating bytecode from GDB expressions: literals */ |
636 | ||
637 | static void | |
fba45db2 KB |
638 | gen_int_literal (struct agent_expr *ax, struct axs_value *value, LONGEST k, |
639 | struct type *type) | |
c906108c SS |
640 | { |
641 | ax_const_l (ax, k); | |
642 | value->kind = axs_rvalue; | |
648027cc | 643 | value->type = check_typedef (type); |
c906108c | 644 | } |
c5aa993b | 645 | \f |
c906108c SS |
646 | |
647 | ||
c906108c SS |
648 | /* Generating bytecode from GDB expressions: unary conversions, casts */ |
649 | ||
650 | /* Take what's on the top of the stack (as described by VALUE), and | |
651 | try to make an rvalue out of it. Signal an error if we can't do | |
652 | that. */ | |
653 | static void | |
fba45db2 | 654 | require_rvalue (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
655 | { |
656 | switch (value->kind) | |
657 | { | |
658 | case axs_rvalue: | |
659 | /* It's already an rvalue. */ | |
660 | break; | |
661 | ||
662 | case axs_lvalue_memory: | |
663 | /* The top of stack is the address of the object. Dereference. */ | |
664 | gen_fetch (ax, value->type); | |
665 | break; | |
666 | ||
667 | case axs_lvalue_register: | |
668 | /* There's nothing on the stack, but value->u.reg is the | |
669 | register number containing the value. | |
670 | ||
c5aa993b JM |
671 | When we add floating-point support, this is going to have to |
672 | change. What about SPARC register pairs, for example? */ | |
c906108c SS |
673 | ax_reg (ax, value->u.reg); |
674 | gen_extend (ax, value->type); | |
675 | break; | |
676 | } | |
677 | ||
678 | value->kind = axs_rvalue; | |
679 | } | |
680 | ||
681 | ||
682 | /* Assume the top of the stack is described by VALUE, and perform the | |
683 | usual unary conversions. This is motivated by ANSI 6.2.2, but of | |
684 | course GDB expressions are not ANSI; they're the mishmash union of | |
685 | a bunch of languages. Rah. | |
686 | ||
687 | NOTE! This function promises to produce an rvalue only when the | |
688 | incoming value is of an appropriate type. In other words, the | |
689 | consumer of the value this function produces may assume the value | |
690 | is an rvalue only after checking its type. | |
691 | ||
692 | The immediate issue is that if the user tries to use a structure or | |
693 | union as an operand of, say, the `+' operator, we don't want to try | |
694 | to convert that structure to an rvalue; require_rvalue will bomb on | |
695 | structs and unions. Rather, we want to simply pass the struct | |
696 | lvalue through unchanged, and let `+' raise an error. */ | |
697 | ||
698 | static void | |
fba45db2 | 699 | gen_usual_unary (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
700 | { |
701 | /* We don't have to generate any code for the usual integral | |
702 | conversions, since values are always represented as full-width on | |
703 | the stack. Should we tweak the type? */ | |
704 | ||
705 | /* Some types require special handling. */ | |
0004e5a2 | 706 | switch (TYPE_CODE (value->type)) |
c906108c SS |
707 | { |
708 | /* Functions get converted to a pointer to the function. */ | |
709 | case TYPE_CODE_FUNC: | |
710 | value->type = lookup_pointer_type (value->type); | |
711 | value->kind = axs_rvalue; /* Should always be true, but just in case. */ | |
712 | break; | |
713 | ||
714 | /* Arrays get converted to a pointer to their first element, and | |
c5aa993b | 715 | are no longer an lvalue. */ |
c906108c SS |
716 | case TYPE_CODE_ARRAY: |
717 | { | |
718 | struct type *elements = TYPE_TARGET_TYPE (value->type); | |
719 | value->type = lookup_pointer_type (elements); | |
720 | value->kind = axs_rvalue; | |
721 | /* We don't need to generate any code; the address of the array | |
722 | is also the address of its first element. */ | |
723 | } | |
c5aa993b | 724 | break; |
c906108c | 725 | |
c5aa993b JM |
726 | /* Don't try to convert structures and unions to rvalues. Let the |
727 | consumer signal an error. */ | |
c906108c SS |
728 | case TYPE_CODE_STRUCT: |
729 | case TYPE_CODE_UNION: | |
730 | return; | |
731 | ||
732 | /* If the value is an enum, call it an integer. */ | |
733 | case TYPE_CODE_ENUM: | |
734 | value->type = builtin_type_int; | |
735 | break; | |
736 | } | |
737 | ||
738 | /* If the value is an lvalue, dereference it. */ | |
739 | require_rvalue (ax, value); | |
740 | } | |
741 | ||
742 | ||
743 | /* Return non-zero iff the type TYPE1 is considered "wider" than the | |
744 | type TYPE2, according to the rules described in gen_usual_arithmetic. */ | |
745 | static int | |
fba45db2 | 746 | type_wider_than (struct type *type1, struct type *type2) |
c906108c SS |
747 | { |
748 | return (TYPE_LENGTH (type1) > TYPE_LENGTH (type2) | |
749 | || (TYPE_LENGTH (type1) == TYPE_LENGTH (type2) | |
750 | && TYPE_UNSIGNED (type1) | |
c5aa993b | 751 | && !TYPE_UNSIGNED (type2))); |
c906108c SS |
752 | } |
753 | ||
754 | ||
755 | /* Return the "wider" of the two types TYPE1 and TYPE2. */ | |
756 | static struct type * | |
fba45db2 | 757 | max_type (struct type *type1, struct type *type2) |
c906108c SS |
758 | { |
759 | return type_wider_than (type1, type2) ? type1 : type2; | |
760 | } | |
761 | ||
762 | ||
763 | /* Generate code to convert a scalar value of type FROM to type TO. */ | |
764 | static void | |
fba45db2 | 765 | gen_conversion (struct agent_expr *ax, struct type *from, struct type *to) |
c906108c SS |
766 | { |
767 | /* Perhaps there is a more graceful way to state these rules. */ | |
768 | ||
769 | /* If we're converting to a narrower type, then we need to clear out | |
770 | the upper bits. */ | |
771 | if (TYPE_LENGTH (to) < TYPE_LENGTH (from)) | |
772 | gen_extend (ax, from); | |
773 | ||
774 | /* If the two values have equal width, but different signednesses, | |
775 | then we need to extend. */ | |
776 | else if (TYPE_LENGTH (to) == TYPE_LENGTH (from)) | |
777 | { | |
778 | if (TYPE_UNSIGNED (from) != TYPE_UNSIGNED (to)) | |
779 | gen_extend (ax, to); | |
780 | } | |
781 | ||
782 | /* If we're converting to a wider type, and becoming unsigned, then | |
783 | we need to zero out any possible sign bits. */ | |
784 | else if (TYPE_LENGTH (to) > TYPE_LENGTH (from)) | |
785 | { | |
786 | if (TYPE_UNSIGNED (to)) | |
787 | gen_extend (ax, to); | |
788 | } | |
789 | } | |
790 | ||
791 | ||
792 | /* Return non-zero iff the type FROM will require any bytecodes to be | |
793 | emitted to be converted to the type TO. */ | |
794 | static int | |
fba45db2 | 795 | is_nontrivial_conversion (struct type *from, struct type *to) |
c906108c SS |
796 | { |
797 | struct agent_expr *ax = new_agent_expr (0); | |
798 | int nontrivial; | |
799 | ||
800 | /* Actually generate the code, and see if anything came out. At the | |
801 | moment, it would be trivial to replicate the code in | |
802 | gen_conversion here, but in the future, when we're supporting | |
803 | floating point and the like, it may not be. Doing things this | |
804 | way allows this function to be independent of the logic in | |
805 | gen_conversion. */ | |
806 | gen_conversion (ax, from, to); | |
807 | nontrivial = ax->len > 0; | |
808 | free_agent_expr (ax); | |
809 | return nontrivial; | |
810 | } | |
811 | ||
812 | ||
813 | /* Generate code to perform the "usual arithmetic conversions" (ANSI C | |
814 | 6.2.1.5) for the two operands of an arithmetic operator. This | |
815 | effectively finds a "least upper bound" type for the two arguments, | |
816 | and promotes each argument to that type. *VALUE1 and *VALUE2 | |
817 | describe the values as they are passed in, and as they are left. */ | |
818 | static void | |
fba45db2 KB |
819 | gen_usual_arithmetic (struct agent_expr *ax, struct axs_value *value1, |
820 | struct axs_value *value2) | |
c906108c SS |
821 | { |
822 | /* Do the usual binary conversions. */ | |
823 | if (TYPE_CODE (value1->type) == TYPE_CODE_INT | |
824 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
825 | { | |
826 | /* The ANSI integral promotions seem to work this way: Order the | |
c5aa993b JM |
827 | integer types by size, and then by signedness: an n-bit |
828 | unsigned type is considered "wider" than an n-bit signed | |
829 | type. Promote to the "wider" of the two types, and always | |
830 | promote at least to int. */ | |
c906108c SS |
831 | struct type *target = max_type (builtin_type_int, |
832 | max_type (value1->type, value2->type)); | |
833 | ||
834 | /* Deal with value2, on the top of the stack. */ | |
835 | gen_conversion (ax, value2->type, target); | |
836 | ||
837 | /* Deal with value1, not on the top of the stack. Don't | |
838 | generate the `swap' instructions if we're not actually going | |
839 | to do anything. */ | |
840 | if (is_nontrivial_conversion (value1->type, target)) | |
841 | { | |
842 | ax_simple (ax, aop_swap); | |
843 | gen_conversion (ax, value1->type, target); | |
844 | ax_simple (ax, aop_swap); | |
845 | } | |
846 | ||
648027cc | 847 | value1->type = value2->type = check_typedef (target); |
c906108c SS |
848 | } |
849 | } | |
850 | ||
851 | ||
852 | /* Generate code to perform the integral promotions (ANSI 6.2.1.1) on | |
853 | the value on the top of the stack, as described by VALUE. Assume | |
854 | the value has integral type. */ | |
855 | static void | |
fba45db2 | 856 | gen_integral_promotions (struct agent_expr *ax, struct axs_value *value) |
c906108c | 857 | { |
c5aa993b | 858 | if (!type_wider_than (value->type, builtin_type_int)) |
c906108c SS |
859 | { |
860 | gen_conversion (ax, value->type, builtin_type_int); | |
861 | value->type = builtin_type_int; | |
862 | } | |
c5aa993b | 863 | else if (!type_wider_than (value->type, builtin_type_unsigned_int)) |
c906108c SS |
864 | { |
865 | gen_conversion (ax, value->type, builtin_type_unsigned_int); | |
866 | value->type = builtin_type_unsigned_int; | |
867 | } | |
868 | } | |
869 | ||
870 | ||
871 | /* Generate code for a cast to TYPE. */ | |
872 | static void | |
fba45db2 | 873 | gen_cast (struct agent_expr *ax, struct axs_value *value, struct type *type) |
c906108c SS |
874 | { |
875 | /* GCC does allow casts to yield lvalues, so this should be fixed | |
876 | before merging these changes into the trunk. */ | |
877 | require_rvalue (ax, value); | |
878 | /* Dereference typedefs. */ | |
879 | type = check_typedef (type); | |
880 | ||
0004e5a2 | 881 | switch (TYPE_CODE (type)) |
c906108c SS |
882 | { |
883 | case TYPE_CODE_PTR: | |
884 | /* It's implementation-defined, and I'll bet this is what GCC | |
885 | does. */ | |
886 | break; | |
887 | ||
888 | case TYPE_CODE_ARRAY: | |
889 | case TYPE_CODE_STRUCT: | |
890 | case TYPE_CODE_UNION: | |
891 | case TYPE_CODE_FUNC: | |
3d263c1d | 892 | error (_("Invalid type cast: intended type must be scalar.")); |
c906108c SS |
893 | |
894 | case TYPE_CODE_ENUM: | |
895 | /* We don't have to worry about the size of the value, because | |
896 | all our integral values are fully sign-extended, and when | |
897 | casting pointers we can do anything we like. Is there any | |
74b35824 JB |
898 | way for us to know what GCC actually does with a cast like |
899 | this? */ | |
c906108c | 900 | break; |
c5aa993b | 901 | |
c906108c SS |
902 | case TYPE_CODE_INT: |
903 | gen_conversion (ax, value->type, type); | |
904 | break; | |
905 | ||
906 | case TYPE_CODE_VOID: | |
907 | /* We could pop the value, and rely on everyone else to check | |
c5aa993b JM |
908 | the type and notice that this value doesn't occupy a stack |
909 | slot. But for now, leave the value on the stack, and | |
910 | preserve the "value == stack element" assumption. */ | |
c906108c SS |
911 | break; |
912 | ||
913 | default: | |
3d263c1d | 914 | error (_("Casts to requested type are not yet implemented.")); |
c906108c SS |
915 | } |
916 | ||
917 | value->type = type; | |
918 | } | |
c5aa993b | 919 | \f |
c906108c SS |
920 | |
921 | ||
c906108c SS |
922 | /* Generating bytecode from GDB expressions: arithmetic */ |
923 | ||
924 | /* Scale the integer on the top of the stack by the size of the target | |
925 | of the pointer type TYPE. */ | |
926 | static void | |
fba45db2 | 927 | gen_scale (struct agent_expr *ax, enum agent_op op, struct type *type) |
c906108c SS |
928 | { |
929 | struct type *element = TYPE_TARGET_TYPE (type); | |
930 | ||
0004e5a2 | 931 | if (TYPE_LENGTH (element) != 1) |
c906108c | 932 | { |
0004e5a2 | 933 | ax_const_l (ax, TYPE_LENGTH (element)); |
c906108c SS |
934 | ax_simple (ax, op); |
935 | } | |
936 | } | |
937 | ||
938 | ||
939 | /* Generate code for an addition; non-trivial because we deal with | |
940 | pointer arithmetic. We set VALUE to describe the result value; we | |
941 | assume VALUE1 and VALUE2 describe the two operands, and that | |
942 | they've undergone the usual binary conversions. Used by both | |
943 | BINOP_ADD and BINOP_SUBSCRIPT. NAME is used in error messages. */ | |
944 | static void | |
fba45db2 KB |
945 | gen_add (struct agent_expr *ax, struct axs_value *value, |
946 | struct axs_value *value1, struct axs_value *value2, char *name) | |
c906108c SS |
947 | { |
948 | /* Is it INT+PTR? */ | |
0004e5a2 DJ |
949 | if (TYPE_CODE (value1->type) == TYPE_CODE_INT |
950 | && TYPE_CODE (value2->type) == TYPE_CODE_PTR) | |
c906108c SS |
951 | { |
952 | /* Swap the values and proceed normally. */ | |
953 | ax_simple (ax, aop_swap); | |
954 | gen_scale (ax, aop_mul, value2->type); | |
955 | ax_simple (ax, aop_add); | |
c5aa993b | 956 | gen_extend (ax, value2->type); /* Catch overflow. */ |
c906108c SS |
957 | value->type = value2->type; |
958 | } | |
959 | ||
960 | /* Is it PTR+INT? */ | |
0004e5a2 DJ |
961 | else if (TYPE_CODE (value1->type) == TYPE_CODE_PTR |
962 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
c906108c SS |
963 | { |
964 | gen_scale (ax, aop_mul, value1->type); | |
965 | ax_simple (ax, aop_add); | |
c5aa993b | 966 | gen_extend (ax, value1->type); /* Catch overflow. */ |
c906108c SS |
967 | value->type = value1->type; |
968 | } | |
969 | ||
970 | /* Must be number + number; the usual binary conversions will have | |
971 | brought them both to the same width. */ | |
0004e5a2 DJ |
972 | else if (TYPE_CODE (value1->type) == TYPE_CODE_INT |
973 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
c906108c SS |
974 | { |
975 | ax_simple (ax, aop_add); | |
c5aa993b | 976 | gen_extend (ax, value1->type); /* Catch overflow. */ |
c906108c SS |
977 | value->type = value1->type; |
978 | } | |
979 | ||
980 | else | |
3d263c1d | 981 | error (_("Invalid combination of types in %s."), name); |
c906108c SS |
982 | |
983 | value->kind = axs_rvalue; | |
984 | } | |
985 | ||
986 | ||
987 | /* Generate code for an addition; non-trivial because we have to deal | |
988 | with pointer arithmetic. We set VALUE to describe the result | |
989 | value; we assume VALUE1 and VALUE2 describe the two operands, and | |
990 | that they've undergone the usual binary conversions. */ | |
991 | static void | |
fba45db2 KB |
992 | gen_sub (struct agent_expr *ax, struct axs_value *value, |
993 | struct axs_value *value1, struct axs_value *value2) | |
c906108c | 994 | { |
0004e5a2 | 995 | if (TYPE_CODE (value1->type) == TYPE_CODE_PTR) |
c906108c SS |
996 | { |
997 | /* Is it PTR - INT? */ | |
0004e5a2 | 998 | if (TYPE_CODE (value2->type) == TYPE_CODE_INT) |
c906108c SS |
999 | { |
1000 | gen_scale (ax, aop_mul, value1->type); | |
1001 | ax_simple (ax, aop_sub); | |
c5aa993b | 1002 | gen_extend (ax, value1->type); /* Catch overflow. */ |
c906108c SS |
1003 | value->type = value1->type; |
1004 | } | |
1005 | ||
1006 | /* Is it PTR - PTR? Strictly speaking, the types ought to | |
c5aa993b JM |
1007 | match, but this is what the normal GDB expression evaluator |
1008 | tests for. */ | |
0004e5a2 | 1009 | else if (TYPE_CODE (value2->type) == TYPE_CODE_PTR |
c906108c SS |
1010 | && (TYPE_LENGTH (TYPE_TARGET_TYPE (value1->type)) |
1011 | == TYPE_LENGTH (TYPE_TARGET_TYPE (value2->type)))) | |
1012 | { | |
1013 | ax_simple (ax, aop_sub); | |
1014 | gen_scale (ax, aop_div_unsigned, value1->type); | |
c5aa993b | 1015 | value->type = builtin_type_long; /* FIXME --- should be ptrdiff_t */ |
c906108c SS |
1016 | } |
1017 | else | |
3d263c1d | 1018 | error (_("\ |
c906108c | 1019 | First argument of `-' is a pointer, but second argument is neither\n\ |
3d263c1d | 1020 | an integer nor a pointer of the same type.")); |
c906108c SS |
1021 | } |
1022 | ||
1023 | /* Must be number + number. */ | |
0004e5a2 DJ |
1024 | else if (TYPE_CODE (value1->type) == TYPE_CODE_INT |
1025 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
c906108c SS |
1026 | { |
1027 | ax_simple (ax, aop_sub); | |
c5aa993b | 1028 | gen_extend (ax, value1->type); /* Catch overflow. */ |
c906108c SS |
1029 | value->type = value1->type; |
1030 | } | |
c5aa993b | 1031 | |
c906108c | 1032 | else |
3d263c1d | 1033 | error (_("Invalid combination of types in subtraction.")); |
c906108c SS |
1034 | |
1035 | value->kind = axs_rvalue; | |
1036 | } | |
1037 | ||
1038 | /* Generate code for a binary operator that doesn't do pointer magic. | |
1039 | We set VALUE to describe the result value; we assume VALUE1 and | |
1040 | VALUE2 describe the two operands, and that they've undergone the | |
1041 | usual binary conversions. MAY_CARRY should be non-zero iff the | |
1042 | result needs to be extended. NAME is the English name of the | |
1043 | operator, used in error messages */ | |
1044 | static void | |
fba45db2 KB |
1045 | gen_binop (struct agent_expr *ax, struct axs_value *value, |
1046 | struct axs_value *value1, struct axs_value *value2, enum agent_op op, | |
1047 | enum agent_op op_unsigned, int may_carry, char *name) | |
c906108c SS |
1048 | { |
1049 | /* We only handle INT op INT. */ | |
0004e5a2 DJ |
1050 | if ((TYPE_CODE (value1->type) != TYPE_CODE_INT) |
1051 | || (TYPE_CODE (value2->type) != TYPE_CODE_INT)) | |
3d263c1d | 1052 | error (_("Invalid combination of types in %s."), name); |
c5aa993b | 1053 | |
c906108c SS |
1054 | ax_simple (ax, |
1055 | TYPE_UNSIGNED (value1->type) ? op_unsigned : op); | |
1056 | if (may_carry) | |
c5aa993b | 1057 | gen_extend (ax, value1->type); /* catch overflow */ |
c906108c SS |
1058 | value->type = value1->type; |
1059 | value->kind = axs_rvalue; | |
1060 | } | |
1061 | ||
1062 | ||
1063 | static void | |
fba45db2 | 1064 | gen_logical_not (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1065 | { |
1066 | if (TYPE_CODE (value->type) != TYPE_CODE_INT | |
1067 | && TYPE_CODE (value->type) != TYPE_CODE_PTR) | |
3d263c1d | 1068 | error (_("Invalid type of operand to `!'.")); |
c906108c SS |
1069 | |
1070 | gen_usual_unary (ax, value); | |
1071 | ax_simple (ax, aop_log_not); | |
1072 | value->type = builtin_type_int; | |
1073 | } | |
1074 | ||
1075 | ||
1076 | static void | |
fba45db2 | 1077 | gen_complement (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1078 | { |
1079 | if (TYPE_CODE (value->type) != TYPE_CODE_INT) | |
3d263c1d | 1080 | error (_("Invalid type of operand to `~'.")); |
c906108c SS |
1081 | |
1082 | gen_usual_unary (ax, value); | |
1083 | gen_integral_promotions (ax, value); | |
1084 | ax_simple (ax, aop_bit_not); | |
1085 | gen_extend (ax, value->type); | |
1086 | } | |
c5aa993b | 1087 | \f |
c906108c SS |
1088 | |
1089 | ||
c906108c SS |
1090 | /* Generating bytecode from GDB expressions: * & . -> @ sizeof */ |
1091 | ||
1092 | /* Dereference the value on the top of the stack. */ | |
1093 | static void | |
fba45db2 | 1094 | gen_deref (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1095 | { |
1096 | /* The caller should check the type, because several operators use | |
1097 | this, and we don't know what error message to generate. */ | |
0004e5a2 | 1098 | if (TYPE_CODE (value->type) != TYPE_CODE_PTR) |
8e65ff28 | 1099 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1100 | _("gen_deref: expected a pointer")); |
c906108c SS |
1101 | |
1102 | /* We've got an rvalue now, which is a pointer. We want to yield an | |
1103 | lvalue, whose address is exactly that pointer. So we don't | |
1104 | actually emit any code; we just change the type from "Pointer to | |
1105 | T" to "T", and mark the value as an lvalue in memory. Leave it | |
1106 | to the consumer to actually dereference it. */ | |
1107 | value->type = check_typedef (TYPE_TARGET_TYPE (value->type)); | |
0004e5a2 | 1108 | value->kind = ((TYPE_CODE (value->type) == TYPE_CODE_FUNC) |
c906108c SS |
1109 | ? axs_rvalue : axs_lvalue_memory); |
1110 | } | |
1111 | ||
1112 | ||
1113 | /* Produce the address of the lvalue on the top of the stack. */ | |
1114 | static void | |
fba45db2 | 1115 | gen_address_of (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1116 | { |
1117 | /* Special case for taking the address of a function. The ANSI | |
1118 | standard describes this as a special case, too, so this | |
1119 | arrangement is not without motivation. */ | |
0004e5a2 | 1120 | if (TYPE_CODE (value->type) == TYPE_CODE_FUNC) |
c906108c SS |
1121 | /* The value's already an rvalue on the stack, so we just need to |
1122 | change the type. */ | |
1123 | value->type = lookup_pointer_type (value->type); | |
1124 | else | |
1125 | switch (value->kind) | |
1126 | { | |
1127 | case axs_rvalue: | |
3d263c1d | 1128 | error (_("Operand of `&' is an rvalue, which has no address.")); |
c906108c SS |
1129 | |
1130 | case axs_lvalue_register: | |
3d263c1d | 1131 | error (_("Operand of `&' is in a register, and has no address.")); |
c906108c SS |
1132 | |
1133 | case axs_lvalue_memory: | |
1134 | value->kind = axs_rvalue; | |
1135 | value->type = lookup_pointer_type (value->type); | |
1136 | break; | |
1137 | } | |
1138 | } | |
1139 | ||
1140 | ||
1141 | /* A lot of this stuff will have to change to support C++. But we're | |
1142 | not going to deal with that at the moment. */ | |
1143 | ||
1144 | /* Find the field in the structure type TYPE named NAME, and return | |
1145 | its index in TYPE's field array. */ | |
1146 | static int | |
fba45db2 | 1147 | find_field (struct type *type, char *name) |
c906108c SS |
1148 | { |
1149 | int i; | |
1150 | ||
1151 | CHECK_TYPEDEF (type); | |
1152 | ||
1153 | /* Make sure this isn't C++. */ | |
1154 | if (TYPE_N_BASECLASSES (type) != 0) | |
8e65ff28 | 1155 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1156 | _("find_field: derived classes supported")); |
c906108c SS |
1157 | |
1158 | for (i = 0; i < TYPE_NFIELDS (type); i++) | |
1159 | { | |
1160 | char *this_name = TYPE_FIELD_NAME (type, i); | |
1161 | ||
747f3d18 MS |
1162 | if (this_name) |
1163 | { | |
1164 | if (strcmp (name, this_name) == 0) | |
1165 | return i; | |
c906108c | 1166 | |
747f3d18 MS |
1167 | if (this_name[0] == '\0') |
1168 | internal_error (__FILE__, __LINE__, | |
1169 | _("find_field: anonymous unions not supported")); | |
1170 | } | |
c906108c SS |
1171 | } |
1172 | ||
3d263c1d | 1173 | error (_("Couldn't find member named `%s' in struct/union `%s'"), |
7495dfdb | 1174 | name, TYPE_TAG_NAME (type)); |
c906108c SS |
1175 | |
1176 | return 0; | |
1177 | } | |
1178 | ||
1179 | ||
1180 | /* Generate code to push the value of a bitfield of a structure whose | |
1181 | address is on the top of the stack. START and END give the | |
1182 | starting and one-past-ending *bit* numbers of the field within the | |
1183 | structure. */ | |
1184 | static void | |
fba45db2 KB |
1185 | gen_bitfield_ref (struct agent_expr *ax, struct axs_value *value, |
1186 | struct type *type, int start, int end) | |
c906108c SS |
1187 | { |
1188 | /* Note that ops[i] fetches 8 << i bits. */ | |
1189 | static enum agent_op ops[] | |
c5aa993b JM |
1190 | = |
1191 | {aop_ref8, aop_ref16, aop_ref32, aop_ref64}; | |
c906108c SS |
1192 | static int num_ops = (sizeof (ops) / sizeof (ops[0])); |
1193 | ||
1194 | /* We don't want to touch any byte that the bitfield doesn't | |
1195 | actually occupy; we shouldn't make any accesses we're not | |
1196 | explicitly permitted to. We rely here on the fact that the | |
1197 | bytecode `ref' operators work on unaligned addresses. | |
1198 | ||
1199 | It takes some fancy footwork to get the stack to work the way | |
1200 | we'd like. Say we're retrieving a bitfield that requires three | |
1201 | fetches. Initially, the stack just contains the address: | |
c5aa993b | 1202 | addr |
c906108c | 1203 | For the first fetch, we duplicate the address |
c5aa993b | 1204 | addr addr |
c906108c SS |
1205 | then add the byte offset, do the fetch, and shift and mask as |
1206 | needed, yielding a fragment of the value, properly aligned for | |
1207 | the final bitwise or: | |
c5aa993b | 1208 | addr frag1 |
c906108c | 1209 | then we swap, and repeat the process: |
c5aa993b JM |
1210 | frag1 addr --- address on top |
1211 | frag1 addr addr --- duplicate it | |
1212 | frag1 addr frag2 --- get second fragment | |
1213 | frag1 frag2 addr --- swap again | |
1214 | frag1 frag2 frag3 --- get third fragment | |
c906108c SS |
1215 | Notice that, since the third fragment is the last one, we don't |
1216 | bother duplicating the address this time. Now we have all the | |
1217 | fragments on the stack, and we can simply `or' them together, | |
1218 | yielding the final value of the bitfield. */ | |
1219 | ||
1220 | /* The first and one-after-last bits in the field, but rounded down | |
1221 | and up to byte boundaries. */ | |
1222 | int bound_start = (start / TARGET_CHAR_BIT) * TARGET_CHAR_BIT; | |
c5aa993b JM |
1223 | int bound_end = (((end + TARGET_CHAR_BIT - 1) |
1224 | / TARGET_CHAR_BIT) | |
1225 | * TARGET_CHAR_BIT); | |
c906108c SS |
1226 | |
1227 | /* current bit offset within the structure */ | |
1228 | int offset; | |
1229 | ||
1230 | /* The index in ops of the opcode we're considering. */ | |
1231 | int op; | |
1232 | ||
1233 | /* The number of fragments we generated in the process. Probably | |
1234 | equal to the number of `one' bits in bytesize, but who cares? */ | |
1235 | int fragment_count; | |
1236 | ||
1237 | /* Dereference any typedefs. */ | |
1238 | type = check_typedef (type); | |
1239 | ||
1240 | /* Can we fetch the number of bits requested at all? */ | |
1241 | if ((end - start) > ((1 << num_ops) * 8)) | |
8e65ff28 | 1242 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1243 | _("gen_bitfield_ref: bitfield too wide")); |
c906108c SS |
1244 | |
1245 | /* Note that we know here that we only need to try each opcode once. | |
1246 | That may not be true on machines with weird byte sizes. */ | |
1247 | offset = bound_start; | |
1248 | fragment_count = 0; | |
1249 | for (op = num_ops - 1; op >= 0; op--) | |
1250 | { | |
1251 | /* number of bits that ops[op] would fetch */ | |
1252 | int op_size = 8 << op; | |
1253 | ||
1254 | /* The stack at this point, from bottom to top, contains zero or | |
c5aa993b JM |
1255 | more fragments, then the address. */ |
1256 | ||
c906108c SS |
1257 | /* Does this fetch fit within the bitfield? */ |
1258 | if (offset + op_size <= bound_end) | |
1259 | { | |
1260 | /* Is this the last fragment? */ | |
1261 | int last_frag = (offset + op_size == bound_end); | |
1262 | ||
c5aa993b JM |
1263 | if (!last_frag) |
1264 | ax_simple (ax, aop_dup); /* keep a copy of the address */ | |
1265 | ||
c906108c SS |
1266 | /* Add the offset. */ |
1267 | gen_offset (ax, offset / TARGET_CHAR_BIT); | |
1268 | ||
1269 | if (trace_kludge) | |
1270 | { | |
1271 | /* Record the area of memory we're about to fetch. */ | |
1272 | ax_trace_quick (ax, op_size / TARGET_CHAR_BIT); | |
1273 | } | |
1274 | ||
1275 | /* Perform the fetch. */ | |
1276 | ax_simple (ax, ops[op]); | |
c5aa993b JM |
1277 | |
1278 | /* Shift the bits we have to their proper position. | |
c906108c SS |
1279 | gen_left_shift will generate right shifts when the operand |
1280 | is negative. | |
1281 | ||
c5aa993b JM |
1282 | A big-endian field diagram to ponder: |
1283 | byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 byte 6 byte 7 | |
1284 | +------++------++------++------++------++------++------++------+ | |
1285 | xxxxAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBCCCCCxxxxxxxxxxx | |
1286 | ^ ^ ^ ^ | |
1287 | bit number 16 32 48 53 | |
c906108c SS |
1288 | These are bit numbers as supplied by GDB. Note that the |
1289 | bit numbers run from right to left once you've fetched the | |
1290 | value! | |
1291 | ||
c5aa993b JM |
1292 | A little-endian field diagram to ponder: |
1293 | byte 7 byte 6 byte 5 byte 4 byte 3 byte 2 byte 1 byte 0 | |
1294 | +------++------++------++------++------++------++------++------+ | |
1295 | xxxxxxxxxxxAAAAABBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCCCCCCCCCCCxxxx | |
1296 | ^ ^ ^ ^ ^ | |
1297 | bit number 48 32 16 4 0 | |
1298 | ||
1299 | In both cases, the most significant end is on the left | |
1300 | (i.e. normal numeric writing order), which means that you | |
1301 | don't go crazy thinking about `left' and `right' shifts. | |
1302 | ||
1303 | We don't have to worry about masking yet: | |
1304 | - If they contain garbage off the least significant end, then we | |
1305 | must be looking at the low end of the field, and the right | |
1306 | shift will wipe them out. | |
1307 | - If they contain garbage off the most significant end, then we | |
1308 | must be looking at the most significant end of the word, and | |
1309 | the sign/zero extension will wipe them out. | |
1310 | - If we're in the interior of the word, then there is no garbage | |
1311 | on either end, because the ref operators zero-extend. */ | |
0d20ae72 | 1312 | if (gdbarch_byte_order (current_gdbarch) == BFD_ENDIAN_BIG) |
c906108c | 1313 | gen_left_shift (ax, end - (offset + op_size)); |
c5aa993b | 1314 | else |
c906108c SS |
1315 | gen_left_shift (ax, offset - start); |
1316 | ||
c5aa993b | 1317 | if (!last_frag) |
c906108c SS |
1318 | /* Bring the copy of the address up to the top. */ |
1319 | ax_simple (ax, aop_swap); | |
1320 | ||
1321 | offset += op_size; | |
1322 | fragment_count++; | |
1323 | } | |
1324 | } | |
1325 | ||
1326 | /* Generate enough bitwise `or' operations to combine all the | |
1327 | fragments we left on the stack. */ | |
1328 | while (fragment_count-- > 1) | |
1329 | ax_simple (ax, aop_bit_or); | |
1330 | ||
1331 | /* Sign- or zero-extend the value as appropriate. */ | |
1332 | ((TYPE_UNSIGNED (type) ? ax_zero_ext : ax_ext) (ax, end - start)); | |
1333 | ||
1334 | /* This is *not* an lvalue. Ugh. */ | |
1335 | value->kind = axs_rvalue; | |
1336 | value->type = type; | |
1337 | } | |
1338 | ||
1339 | ||
1340 | /* Generate code to reference the member named FIELD of a structure or | |
1341 | union. The top of the stack, as described by VALUE, should have | |
1342 | type (pointer to a)* struct/union. OPERATOR_NAME is the name of | |
1343 | the operator being compiled, and OPERAND_NAME is the kind of thing | |
1344 | it operates on; we use them in error messages. */ | |
1345 | static void | |
fba45db2 KB |
1346 | gen_struct_ref (struct agent_expr *ax, struct axs_value *value, char *field, |
1347 | char *operator_name, char *operand_name) | |
c906108c SS |
1348 | { |
1349 | struct type *type; | |
1350 | int i; | |
1351 | ||
1352 | /* Follow pointers until we reach a non-pointer. These aren't the C | |
1353 | semantics, but they're what the normal GDB evaluator does, so we | |
1354 | should at least be consistent. */ | |
0004e5a2 | 1355 | while (TYPE_CODE (value->type) == TYPE_CODE_PTR) |
c906108c SS |
1356 | { |
1357 | gen_usual_unary (ax, value); | |
1358 | gen_deref (ax, value); | |
1359 | } | |
e8860ec2 | 1360 | type = check_typedef (value->type); |
c906108c SS |
1361 | |
1362 | /* This must yield a structure or a union. */ | |
1363 | if (TYPE_CODE (type) != TYPE_CODE_STRUCT | |
1364 | && TYPE_CODE (type) != TYPE_CODE_UNION) | |
3d263c1d | 1365 | error (_("The left operand of `%s' is not a %s."), |
c906108c SS |
1366 | operator_name, operand_name); |
1367 | ||
1368 | /* And it must be in memory; we don't deal with structure rvalues, | |
1369 | or structures living in registers. */ | |
1370 | if (value->kind != axs_lvalue_memory) | |
3d263c1d | 1371 | error (_("Structure does not live in memory.")); |
c906108c SS |
1372 | |
1373 | i = find_field (type, field); | |
c5aa993b | 1374 | |
c906108c SS |
1375 | /* Is this a bitfield? */ |
1376 | if (TYPE_FIELD_PACKED (type, i)) | |
1377 | gen_bitfield_ref (ax, value, TYPE_FIELD_TYPE (type, i), | |
1378 | TYPE_FIELD_BITPOS (type, i), | |
1379 | (TYPE_FIELD_BITPOS (type, i) | |
1380 | + TYPE_FIELD_BITSIZE (type, i))); | |
1381 | else | |
1382 | { | |
1383 | gen_offset (ax, TYPE_FIELD_BITPOS (type, i) / TARGET_CHAR_BIT); | |
1384 | value->kind = axs_lvalue_memory; | |
1385 | value->type = TYPE_FIELD_TYPE (type, i); | |
1386 | } | |
1387 | } | |
1388 | ||
1389 | ||
1390 | /* Generate code for GDB's magical `repeat' operator. | |
1391 | LVALUE @ INT creates an array INT elements long, and whose elements | |
1392 | have the same type as LVALUE, located in memory so that LVALUE is | |
1393 | its first element. For example, argv[0]@argc gives you the array | |
1394 | of command-line arguments. | |
1395 | ||
1396 | Unfortunately, because we have to know the types before we actually | |
1397 | have a value for the expression, we can't implement this perfectly | |
1398 | without changing the type system, having values that occupy two | |
1399 | stack slots, doing weird things with sizeof, etc. So we require | |
1400 | the right operand to be a constant expression. */ | |
1401 | static void | |
fba45db2 KB |
1402 | gen_repeat (union exp_element **pc, struct agent_expr *ax, |
1403 | struct axs_value *value) | |
c906108c SS |
1404 | { |
1405 | struct axs_value value1; | |
1406 | /* We don't want to turn this into an rvalue, so no conversions | |
1407 | here. */ | |
1408 | gen_expr (pc, ax, &value1); | |
1409 | if (value1.kind != axs_lvalue_memory) | |
3d263c1d | 1410 | error (_("Left operand of `@' must be an object in memory.")); |
c906108c SS |
1411 | |
1412 | /* Evaluate the length; it had better be a constant. */ | |
1413 | { | |
1414 | struct value *v = const_expr (pc); | |
1415 | int length; | |
1416 | ||
c5aa993b | 1417 | if (!v) |
3d263c1d | 1418 | error (_("Right operand of `@' must be a constant, in agent expressions.")); |
04624583 | 1419 | if (TYPE_CODE (value_type (v)) != TYPE_CODE_INT) |
3d263c1d | 1420 | error (_("Right operand of `@' must be an integer.")); |
c906108c SS |
1421 | length = value_as_long (v); |
1422 | if (length <= 0) | |
3d263c1d | 1423 | error (_("Right operand of `@' must be positive.")); |
c906108c SS |
1424 | |
1425 | /* The top of the stack is already the address of the object, so | |
1426 | all we need to do is frob the type of the lvalue. */ | |
1427 | { | |
1428 | /* FIXME-type-allocation: need a way to free this type when we are | |
c5aa993b | 1429 | done with it. */ |
c906108c | 1430 | struct type *range |
c5aa993b | 1431 | = create_range_type (0, builtin_type_int, 0, length - 1); |
c906108c SS |
1432 | struct type *array = create_array_type (0, value1.type, range); |
1433 | ||
1434 | value->kind = axs_lvalue_memory; | |
1435 | value->type = array; | |
1436 | } | |
1437 | } | |
1438 | } | |
1439 | ||
1440 | ||
1441 | /* Emit code for the `sizeof' operator. | |
1442 | *PC should point at the start of the operand expression; we advance it | |
1443 | to the first instruction after the operand. */ | |
1444 | static void | |
fba45db2 KB |
1445 | gen_sizeof (union exp_element **pc, struct agent_expr *ax, |
1446 | struct axs_value *value) | |
c906108c SS |
1447 | { |
1448 | /* We don't care about the value of the operand expression; we only | |
1449 | care about its type. However, in the current arrangement, the | |
1450 | only way to find an expression's type is to generate code for it. | |
1451 | So we generate code for the operand, and then throw it away, | |
1452 | replacing it with code that simply pushes its size. */ | |
1453 | int start = ax->len; | |
1454 | gen_expr (pc, ax, value); | |
1455 | ||
1456 | /* Throw away the code we just generated. */ | |
1457 | ax->len = start; | |
c5aa993b | 1458 | |
c906108c SS |
1459 | ax_const_l (ax, TYPE_LENGTH (value->type)); |
1460 | value->kind = axs_rvalue; | |
1461 | value->type = builtin_type_int; | |
1462 | } | |
c906108c | 1463 | \f |
c5aa993b | 1464 | |
c906108c SS |
1465 | /* Generating bytecode from GDB expressions: general recursive thingy */ |
1466 | ||
3d263c1d | 1467 | /* XXX: i18n */ |
c906108c SS |
1468 | /* A gen_expr function written by a Gen-X'er guy. |
1469 | Append code for the subexpression of EXPR starting at *POS_P to AX. */ | |
1470 | static void | |
fba45db2 KB |
1471 | gen_expr (union exp_element **pc, struct agent_expr *ax, |
1472 | struct axs_value *value) | |
c906108c SS |
1473 | { |
1474 | /* Used to hold the descriptions of operand expressions. */ | |
1475 | struct axs_value value1, value2; | |
1476 | enum exp_opcode op = (*pc)[0].opcode; | |
1477 | ||
1478 | /* If we're looking at a constant expression, just push its value. */ | |
1479 | { | |
1480 | struct value *v = maybe_const_expr (pc); | |
c5aa993b | 1481 | |
c906108c SS |
1482 | if (v) |
1483 | { | |
1484 | ax_const_l (ax, value_as_long (v)); | |
1485 | value->kind = axs_rvalue; | |
df407dfe | 1486 | value->type = check_typedef (value_type (v)); |
c906108c SS |
1487 | return; |
1488 | } | |
1489 | } | |
1490 | ||
1491 | /* Otherwise, go ahead and generate code for it. */ | |
1492 | switch (op) | |
1493 | { | |
1494 | /* Binary arithmetic operators. */ | |
1495 | case BINOP_ADD: | |
1496 | case BINOP_SUB: | |
1497 | case BINOP_MUL: | |
1498 | case BINOP_DIV: | |
1499 | case BINOP_REM: | |
1500 | case BINOP_SUBSCRIPT: | |
1501 | case BINOP_BITWISE_AND: | |
1502 | case BINOP_BITWISE_IOR: | |
1503 | case BINOP_BITWISE_XOR: | |
1504 | (*pc)++; | |
1505 | gen_expr (pc, ax, &value1); | |
1506 | gen_usual_unary (ax, &value1); | |
1507 | gen_expr (pc, ax, &value2); | |
1508 | gen_usual_unary (ax, &value2); | |
1509 | gen_usual_arithmetic (ax, &value1, &value2); | |
1510 | switch (op) | |
1511 | { | |
1512 | case BINOP_ADD: | |
1513 | gen_add (ax, value, &value1, &value2, "addition"); | |
1514 | break; | |
1515 | case BINOP_SUB: | |
1516 | gen_sub (ax, value, &value1, &value2); | |
1517 | break; | |
1518 | case BINOP_MUL: | |
1519 | gen_binop (ax, value, &value1, &value2, | |
1520 | aop_mul, aop_mul, 1, "multiplication"); | |
1521 | break; | |
1522 | case BINOP_DIV: | |
1523 | gen_binop (ax, value, &value1, &value2, | |
1524 | aop_div_signed, aop_div_unsigned, 1, "division"); | |
1525 | break; | |
1526 | case BINOP_REM: | |
1527 | gen_binop (ax, value, &value1, &value2, | |
1528 | aop_rem_signed, aop_rem_unsigned, 1, "remainder"); | |
1529 | break; | |
1530 | case BINOP_SUBSCRIPT: | |
1531 | gen_add (ax, value, &value1, &value2, "array subscripting"); | |
1532 | if (TYPE_CODE (value->type) != TYPE_CODE_PTR) | |
3d263c1d | 1533 | error (_("Invalid combination of types in array subscripting.")); |
c906108c SS |
1534 | gen_deref (ax, value); |
1535 | break; | |
1536 | case BINOP_BITWISE_AND: | |
1537 | gen_binop (ax, value, &value1, &value2, | |
1538 | aop_bit_and, aop_bit_and, 0, "bitwise and"); | |
1539 | break; | |
1540 | ||
1541 | case BINOP_BITWISE_IOR: | |
1542 | gen_binop (ax, value, &value1, &value2, | |
1543 | aop_bit_or, aop_bit_or, 0, "bitwise or"); | |
1544 | break; | |
1545 | ||
1546 | case BINOP_BITWISE_XOR: | |
1547 | gen_binop (ax, value, &value1, &value2, | |
1548 | aop_bit_xor, aop_bit_xor, 0, "bitwise exclusive-or"); | |
1549 | break; | |
1550 | ||
1551 | default: | |
1552 | /* We should only list operators in the outer case statement | |
c5aa993b | 1553 | that we actually handle in the inner case statement. */ |
8e65ff28 | 1554 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1555 | _("gen_expr: op case sets don't match")); |
c906108c SS |
1556 | } |
1557 | break; | |
1558 | ||
1559 | /* Note that we need to be a little subtle about generating code | |
c5aa993b JM |
1560 | for comma. In C, we can do some optimizations here because |
1561 | we know the left operand is only being evaluated for effect. | |
1562 | However, if the tracing kludge is in effect, then we always | |
1563 | need to evaluate the left hand side fully, so that all the | |
1564 | variables it mentions get traced. */ | |
c906108c SS |
1565 | case BINOP_COMMA: |
1566 | (*pc)++; | |
1567 | gen_expr (pc, ax, &value1); | |
1568 | /* Don't just dispose of the left operand. We might be tracing, | |
c5aa993b JM |
1569 | in which case we want to emit code to trace it if it's an |
1570 | lvalue. */ | |
c906108c SS |
1571 | gen_traced_pop (ax, &value1); |
1572 | gen_expr (pc, ax, value); | |
1573 | /* It's the consumer's responsibility to trace the right operand. */ | |
1574 | break; | |
c5aa993b | 1575 | |
c906108c SS |
1576 | case OP_LONG: /* some integer constant */ |
1577 | { | |
1578 | struct type *type = (*pc)[1].type; | |
1579 | LONGEST k = (*pc)[2].longconst; | |
1580 | (*pc) += 4; | |
1581 | gen_int_literal (ax, value, k, type); | |
1582 | } | |
c5aa993b | 1583 | break; |
c906108c SS |
1584 | |
1585 | case OP_VAR_VALUE: | |
1586 | gen_var_ref (ax, value, (*pc)[2].symbol); | |
1587 | (*pc) += 4; | |
1588 | break; | |
1589 | ||
1590 | case OP_REGISTER: | |
1591 | { | |
67f3407f DJ |
1592 | const char *name = &(*pc)[2].string; |
1593 | int reg; | |
1594 | (*pc) += 4 + BYTES_TO_EXP_ELEM ((*pc)[1].longconst + 1); | |
1595 | reg = frame_map_name_to_regnum (deprecated_safe_get_selected_frame (), | |
1596 | name, strlen (name)); | |
1597 | if (reg == -1) | |
1598 | internal_error (__FILE__, __LINE__, | |
1599 | _("Register $%s not available"), name); | |
02e4669d JB |
1600 | if (reg >= gdbarch_num_regs (current_gdbarch)) |
1601 | error (_("'%s' is a pseudo-register; " | |
1602 | "GDB cannot yet trace pseudoregister contents."), | |
1603 | name); | |
c906108c SS |
1604 | value->kind = axs_lvalue_register; |
1605 | value->u.reg = reg; | |
7b83296f | 1606 | value->type = register_type (current_gdbarch, reg); |
c906108c | 1607 | } |
c5aa993b | 1608 | break; |
c906108c SS |
1609 | |
1610 | case OP_INTERNALVAR: | |
3d263c1d | 1611 | error (_("GDB agent expressions cannot use convenience variables.")); |
c906108c | 1612 | |
c5aa993b | 1613 | /* Weirdo operator: see comments for gen_repeat for details. */ |
c906108c SS |
1614 | case BINOP_REPEAT: |
1615 | /* Note that gen_repeat handles its own argument evaluation. */ | |
1616 | (*pc)++; | |
1617 | gen_repeat (pc, ax, value); | |
1618 | break; | |
1619 | ||
1620 | case UNOP_CAST: | |
1621 | { | |
1622 | struct type *type = (*pc)[1].type; | |
1623 | (*pc) += 3; | |
1624 | gen_expr (pc, ax, value); | |
1625 | gen_cast (ax, value, type); | |
1626 | } | |
c5aa993b | 1627 | break; |
c906108c SS |
1628 | |
1629 | case UNOP_MEMVAL: | |
1630 | { | |
1631 | struct type *type = check_typedef ((*pc)[1].type); | |
1632 | (*pc) += 3; | |
1633 | gen_expr (pc, ax, value); | |
1634 | /* I'm not sure I understand UNOP_MEMVAL entirely. I think | |
1635 | it's just a hack for dealing with minsyms; you take some | |
1636 | integer constant, pretend it's the address of an lvalue of | |
1637 | the given type, and dereference it. */ | |
1638 | if (value->kind != axs_rvalue) | |
1639 | /* This would be weird. */ | |
8e65ff28 | 1640 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1641 | _("gen_expr: OP_MEMVAL operand isn't an rvalue???")); |
c906108c SS |
1642 | value->type = type; |
1643 | value->kind = axs_lvalue_memory; | |
1644 | } | |
c5aa993b | 1645 | break; |
c906108c | 1646 | |
36e9969c NS |
1647 | case UNOP_PLUS: |
1648 | (*pc)++; | |
1649 | /* + FOO is equivalent to 0 + FOO, which can be optimized. */ | |
1650 | gen_expr (pc, ax, value); | |
1651 | gen_usual_unary (ax, value); | |
1652 | break; | |
1653 | ||
c906108c SS |
1654 | case UNOP_NEG: |
1655 | (*pc)++; | |
1656 | /* -FOO is equivalent to 0 - FOO. */ | |
1657 | gen_int_literal (ax, &value1, (LONGEST) 0, builtin_type_int); | |
c5aa993b | 1658 | gen_usual_unary (ax, &value1); /* shouldn't do much */ |
c906108c SS |
1659 | gen_expr (pc, ax, &value2); |
1660 | gen_usual_unary (ax, &value2); | |
1661 | gen_usual_arithmetic (ax, &value1, &value2); | |
1662 | gen_sub (ax, value, &value1, &value2); | |
1663 | break; | |
1664 | ||
1665 | case UNOP_LOGICAL_NOT: | |
1666 | (*pc)++; | |
1667 | gen_expr (pc, ax, value); | |
1668 | gen_logical_not (ax, value); | |
1669 | break; | |
1670 | ||
1671 | case UNOP_COMPLEMENT: | |
1672 | (*pc)++; | |
1673 | gen_expr (pc, ax, value); | |
1674 | gen_complement (ax, value); | |
1675 | break; | |
1676 | ||
1677 | case UNOP_IND: | |
1678 | (*pc)++; | |
1679 | gen_expr (pc, ax, value); | |
1680 | gen_usual_unary (ax, value); | |
1681 | if (TYPE_CODE (value->type) != TYPE_CODE_PTR) | |
3d263c1d | 1682 | error (_("Argument of unary `*' is not a pointer.")); |
c906108c SS |
1683 | gen_deref (ax, value); |
1684 | break; | |
1685 | ||
1686 | case UNOP_ADDR: | |
1687 | (*pc)++; | |
1688 | gen_expr (pc, ax, value); | |
1689 | gen_address_of (ax, value); | |
1690 | break; | |
1691 | ||
1692 | case UNOP_SIZEOF: | |
1693 | (*pc)++; | |
1694 | /* Notice that gen_sizeof handles its own operand, unlike most | |
c5aa993b JM |
1695 | of the other unary operator functions. This is because we |
1696 | have to throw away the code we generate. */ | |
c906108c SS |
1697 | gen_sizeof (pc, ax, value); |
1698 | break; | |
1699 | ||
1700 | case STRUCTOP_STRUCT: | |
1701 | case STRUCTOP_PTR: | |
1702 | { | |
1703 | int length = (*pc)[1].longconst; | |
1704 | char *name = &(*pc)[2].string; | |
1705 | ||
1706 | (*pc) += 4 + BYTES_TO_EXP_ELEM (length + 1); | |
1707 | gen_expr (pc, ax, value); | |
1708 | if (op == STRUCTOP_STRUCT) | |
1709 | gen_struct_ref (ax, value, name, ".", "structure or union"); | |
1710 | else if (op == STRUCTOP_PTR) | |
1711 | gen_struct_ref (ax, value, name, "->", | |
1712 | "pointer to a structure or union"); | |
1713 | else | |
1714 | /* If this `if' chain doesn't handle it, then the case list | |
c5aa993b | 1715 | shouldn't mention it, and we shouldn't be here. */ |
8e65ff28 | 1716 | internal_error (__FILE__, __LINE__, |
3d263c1d | 1717 | _("gen_expr: unhandled struct case")); |
c906108c | 1718 | } |
c5aa993b | 1719 | break; |
c906108c SS |
1720 | |
1721 | case OP_TYPE: | |
3d263c1d | 1722 | error (_("Attempt to use a type name as an expression.")); |
c906108c SS |
1723 | |
1724 | default: | |
3d263c1d | 1725 | error (_("Unsupported operator in expression.")); |
c906108c SS |
1726 | } |
1727 | } | |
c906108c | 1728 | \f |
c5aa993b JM |
1729 | |
1730 | ||
c906108c SS |
1731 | /* Generating bytecode from GDB expressions: driver */ |
1732 | ||
c906108c SS |
1733 | /* Given a GDB expression EXPR, return bytecode to trace its value. |
1734 | The result will use the `trace' and `trace_quick' bytecodes to | |
1735 | record the value of all memory touched by the expression. The | |
1736 | caller can then use the ax_reqs function to discover which | |
1737 | registers it relies upon. */ | |
1738 | struct agent_expr * | |
fba45db2 | 1739 | gen_trace_for_expr (CORE_ADDR scope, struct expression *expr) |
c906108c SS |
1740 | { |
1741 | struct cleanup *old_chain = 0; | |
1742 | struct agent_expr *ax = new_agent_expr (scope); | |
1743 | union exp_element *pc; | |
1744 | struct axs_value value; | |
1745 | ||
f23d52e0 | 1746 | old_chain = make_cleanup_free_agent_expr (ax); |
c906108c SS |
1747 | |
1748 | pc = expr->elts; | |
1749 | trace_kludge = 1; | |
1750 | gen_expr (&pc, ax, &value); | |
1751 | ||
1752 | /* Make sure we record the final object, and get rid of it. */ | |
1753 | gen_traced_pop (ax, &value); | |
1754 | ||
1755 | /* Oh, and terminate. */ | |
1756 | ax_simple (ax, aop_end); | |
1757 | ||
1758 | /* We have successfully built the agent expr, so cancel the cleanup | |
1759 | request. If we add more cleanups that we always want done, this | |
1760 | will have to get more complicated. */ | |
1761 | discard_cleanups (old_chain); | |
1762 | return ax; | |
1763 | } | |
c906108c SS |
1764 | |
1765 | static void | |
fba45db2 | 1766 | agent_command (char *exp, int from_tty) |
c906108c SS |
1767 | { |
1768 | struct cleanup *old_chain = 0; | |
1769 | struct expression *expr; | |
1770 | struct agent_expr *agent; | |
6426a772 | 1771 | struct frame_info *fi = get_current_frame (); /* need current scope */ |
c906108c SS |
1772 | |
1773 | /* We don't deal with overlay debugging at the moment. We need to | |
1774 | think more carefully about this. If you copy this code into | |
1775 | another command, change the error message; the user shouldn't | |
1776 | have to know anything about agent expressions. */ | |
1777 | if (overlay_debugging) | |
3d263c1d | 1778 | error (_("GDB can't do agent expression translation with overlays.")); |
c906108c SS |
1779 | |
1780 | if (exp == 0) | |
3d263c1d | 1781 | error_no_arg (_("expression to translate")); |
c5aa993b | 1782 | |
c906108c | 1783 | expr = parse_expression (exp); |
c13c43fd | 1784 | old_chain = make_cleanup (free_current_contents, &expr); |
bdd78e62 | 1785 | agent = gen_trace_for_expr (get_frame_pc (fi), expr); |
f23d52e0 | 1786 | make_cleanup_free_agent_expr (agent); |
c906108c | 1787 | ax_print (gdb_stdout, agent); |
085dd6e6 JM |
1788 | |
1789 | /* It would be nice to call ax_reqs here to gather some general info | |
1790 | about the expression, and then print out the result. */ | |
c906108c SS |
1791 | |
1792 | do_cleanups (old_chain); | |
1793 | dont_repeat (); | |
1794 | } | |
c906108c | 1795 | \f |
c5aa993b | 1796 | |
c906108c SS |
1797 | /* Initialization code. */ |
1798 | ||
a14ed312 | 1799 | void _initialize_ax_gdb (void); |
c906108c | 1800 | void |
fba45db2 | 1801 | _initialize_ax_gdb (void) |
c906108c | 1802 | { |
c906108c | 1803 | add_cmd ("agent", class_maintenance, agent_command, |
3d263c1d | 1804 | _("Translate an expression into remote agent bytecode."), |
c906108c SS |
1805 | &maintenancelist); |
1806 | } |