1 /* GDB-specific functions for operating on agent expressions.
3 Copyright (C) 1998, 1999, 2000, 2001, 2003, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
6 This file is part of GDB.
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
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
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.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
27 #include "expression.h"
34 #include "gdb_string.h"
37 #include "user-regs.h"
39 #include "dictionary.h"
40 #include "breakpoint.h"
41 #include "tracepoint.h"
42 #include "cp-support.h"
44 /* To make sense of this file, you should read doc/agentexpr.texi.
45 Then look at the types and enums in ax-gdb.h. For the code itself,
46 look at gen_expr, towards the bottom; that's the main function that
47 looks at the GDB expressions and calls everything else to generate
50 I'm beginning to wonder whether it wouldn't be nicer to internally
51 generate trees, with types, and then spit out the bytecode in
52 linear form afterwards; we could generate fewer `swap', `ext', and
53 `zero_ext' bytecodes that way; it would make good constant folding
54 easier, too. But at the moment, I think we should be willing to
55 pay for the simplicity of this code with less-than-optimal bytecode
58 Remember, "GBD" stands for "Great Britain, Dammit!" So be careful. */
62 /* Prototypes for local functions. */
64 /* There's a standard order to the arguments of these functions:
65 union exp_element ** --- pointer into expression
66 struct agent_expr * --- agent expression buffer to generate code into
67 struct axs_value * --- describes value left on top of stack */
69 static struct value *const_var_ref (struct symbol *var);
70 static struct value *const_expr (union exp_element **pc);
71 static struct value *maybe_const_expr (union exp_element **pc);
73 static void gen_traced_pop (struct gdbarch *, struct agent_expr *, struct axs_value *);
75 static void gen_sign_extend (struct agent_expr *, struct type *);
76 static void gen_extend (struct agent_expr *, struct type *);
77 static void gen_fetch (struct agent_expr *, struct type *);
78 static void gen_left_shift (struct agent_expr *, int);
81 static void gen_frame_args_address (struct gdbarch *, struct agent_expr *);
82 static void gen_frame_locals_address (struct gdbarch *, struct agent_expr *);
83 static void gen_offset (struct agent_expr *ax, int offset);
84 static void gen_sym_offset (struct agent_expr *, struct symbol *);
85 static void gen_var_ref (struct gdbarch *, struct agent_expr *ax,
86 struct axs_value *value, struct symbol *var);
89 static void gen_int_literal (struct agent_expr *ax,
90 struct axs_value *value,
91 LONGEST k, struct type *type);
94 static void require_rvalue (struct agent_expr *ax, struct axs_value *value);
95 static void gen_usual_unary (struct expression *exp, struct agent_expr *ax,
96 struct axs_value *value);
97 static int type_wider_than (struct type *type1, struct type *type2);
98 static struct type *max_type (struct type *type1, struct type *type2);
99 static void gen_conversion (struct agent_expr *ax,
100 struct type *from, struct type *to);
101 static int is_nontrivial_conversion (struct type *from, struct type *to);
102 static void gen_usual_arithmetic (struct expression *exp,
103 struct agent_expr *ax,
104 struct axs_value *value1,
105 struct axs_value *value2);
106 static void gen_integral_promotions (struct expression *exp,
107 struct agent_expr *ax,
108 struct axs_value *value);
109 static void gen_cast (struct agent_expr *ax,
110 struct axs_value *value, struct type *type);
111 static void gen_scale (struct agent_expr *ax,
112 enum agent_op op, struct type *type);
113 static void gen_ptradd (struct agent_expr *ax, struct axs_value *value,
114 struct axs_value *value1, struct axs_value *value2);
115 static void gen_ptrsub (struct agent_expr *ax, struct axs_value *value,
116 struct axs_value *value1, struct axs_value *value2);
117 static void gen_ptrdiff (struct agent_expr *ax, struct axs_value *value,
118 struct axs_value *value1, struct axs_value *value2,
119 struct type *result_type);
120 static void gen_binop (struct agent_expr *ax,
121 struct axs_value *value,
122 struct axs_value *value1,
123 struct axs_value *value2,
125 enum agent_op op_unsigned, int may_carry, char *name);
126 static void gen_logical_not (struct agent_expr *ax, struct axs_value *value,
127 struct type *result_type);
128 static void gen_complement (struct agent_expr *ax, struct axs_value *value);
129 static void gen_deref (struct agent_expr *, struct axs_value *);
130 static void gen_address_of (struct agent_expr *, struct axs_value *);
131 static void gen_bitfield_ref (struct expression *exp, struct agent_expr *ax,
132 struct axs_value *value,
133 struct type *type, int start, int end);
134 static void gen_primitive_field (struct expression *exp,
135 struct agent_expr *ax,
136 struct axs_value *value,
137 int offset, int fieldno, struct type *type);
138 static int gen_struct_ref_recursive (struct expression *exp,
139 struct agent_expr *ax,
140 struct axs_value *value,
141 char *field, int offset,
143 static void gen_struct_ref (struct expression *exp, struct agent_expr *ax,
144 struct axs_value *value,
146 char *operator_name, char *operand_name);
147 static void gen_static_field (struct gdbarch *gdbarch,
148 struct agent_expr *ax, struct axs_value *value,
149 struct type *type, int fieldno);
150 static void gen_repeat (struct expression *exp, union exp_element **pc,
151 struct agent_expr *ax, struct axs_value *value);
152 static void gen_sizeof (struct expression *exp, union exp_element **pc,
153 struct agent_expr *ax, struct axs_value *value,
154 struct type *size_type);
155 static void gen_expr (struct expression *exp, union exp_element **pc,
156 struct agent_expr *ax, struct axs_value *value);
157 static void gen_expr_binop_rest (struct expression *exp,
158 enum exp_opcode op, union exp_element **pc,
159 struct agent_expr *ax,
160 struct axs_value *value,
161 struct axs_value *value1,
162 struct axs_value *value2);
164 static void agent_command (char *exp, int from_tty);
167 /* Detecting constant expressions. */
169 /* If the variable reference at *PC is a constant, return its value.
170 Otherwise, return zero.
172 Hey, Wally! How can a variable reference be a constant?
174 Well, Beav, this function really handles the OP_VAR_VALUE operator,
175 not specifically variable references. GDB uses OP_VAR_VALUE to
176 refer to any kind of symbolic reference: function names, enum
177 elements, and goto labels are all handled through the OP_VAR_VALUE
178 operator, even though they're constants. It makes sense given the
181 Gee, Wally, don'cha wonder sometimes if data representations that
182 subvert commonly accepted definitions of terms in favor of heavily
183 context-specific interpretations are really just a tool of the
184 programming hegemony to preserve their power and exclude the
187 static struct value *
188 const_var_ref (struct symbol *var)
190 struct type *type = SYMBOL_TYPE (var);
192 switch (SYMBOL_CLASS (var))
195 return value_from_longest (type, (LONGEST) SYMBOL_VALUE (var));
198 return value_from_pointer (type, (CORE_ADDR) SYMBOL_VALUE_ADDRESS (var));
206 /* If the expression starting at *PC has a constant value, return it.
207 Otherwise, return zero. If we return a value, then *PC will be
208 advanced to the end of it. If we return zero, *PC could be
210 static struct value *
211 const_expr (union exp_element **pc)
213 enum exp_opcode op = (*pc)->opcode;
220 struct type *type = (*pc)[1].type;
221 LONGEST k = (*pc)[2].longconst;
223 return value_from_longest (type, k);
228 struct value *v = const_var_ref ((*pc)[2].symbol);
233 /* We could add more operators in here. */
237 v1 = const_expr (pc);
239 return value_neg (v1);
249 /* Like const_expr, but guarantee also that *PC is undisturbed if the
250 expression is not constant. */
251 static struct value *
252 maybe_const_expr (union exp_element **pc)
254 union exp_element *tentative_pc = *pc;
255 struct value *v = const_expr (&tentative_pc);
257 /* If we got a value, then update the real PC. */
265 /* Generating bytecode from GDB expressions: general assumptions */
267 /* Here are a few general assumptions made throughout the code; if you
268 want to make a change that contradicts one of these, then you'd
269 better scan things pretty thoroughly.
271 - We assume that all values occupy one stack element. For example,
272 sometimes we'll swap to get at the left argument to a binary
273 operator. If we decide that void values should occupy no stack
274 elements, or that synthetic arrays (whose size is determined at
275 run time, created by the `@' operator) should occupy two stack
276 elements (address and length), then this will cause trouble.
278 - We assume the stack elements are infinitely wide, and that we
279 don't have to worry what happens if the user requests an
280 operation that is wider than the actual interpreter's stack.
281 That is, it's up to the interpreter to handle directly all the
282 integer widths the user has access to. (Woe betide the language
285 - We don't support side effects. Thus, we don't have to worry about
286 GCC's generalized lvalues, function calls, etc.
288 - We don't support floating point. Many places where we switch on
289 some type don't bother to include cases for floating point; there
290 may be even more subtle ways this assumption exists. For
291 example, the arguments to % must be integers.
293 - We assume all subexpressions have a static, unchanging type. If
294 we tried to support convenience variables, this would be a
297 - All values on the stack should always be fully zero- or
300 (I wasn't sure whether to choose this or its opposite --- that
301 only addresses are assumed extended --- but it turns out that
302 neither convention completely eliminates spurious extend
303 operations (if everything is always extended, then you have to
304 extend after add, because it could overflow; if nothing is
305 extended, then you end up producing extends whenever you change
306 sizes), and this is simpler.) */
309 /* Generating bytecode from GDB expressions: the `trace' kludge */
311 /* The compiler in this file is a general-purpose mechanism for
312 translating GDB expressions into bytecode. One ought to be able to
313 find a million and one uses for it.
315 However, at the moment it is HOPELESSLY BRAIN-DAMAGED for the sake
316 of expediency. Let he who is without sin cast the first stone.
318 For the data tracing facility, we need to insert `trace' bytecodes
319 before each data fetch; this records all the memory that the
320 expression touches in the course of evaluation, so that memory will
321 be available when the user later tries to evaluate the expression
324 This should be done (I think) in a post-processing pass, that walks
325 an arbitrary agent expression and inserts `trace' operations at the
326 appropriate points. But it's much faster to just hack them
327 directly into the code. And since we're in a crunch, that's what
330 Setting the flag trace_kludge to non-zero enables the code that
331 emits the trace bytecodes at the appropriate points. */
332 static int trace_kludge;
334 /* Scan for all static fields in the given class, including any base
335 classes, and generate tracing bytecodes for each. */
338 gen_trace_static_fields (struct gdbarch *gdbarch,
339 struct agent_expr *ax,
342 int i, nbases = TYPE_N_BASECLASSES (type);
343 struct axs_value value;
345 CHECK_TYPEDEF (type);
347 for (i = TYPE_NFIELDS (type) - 1; i >= nbases; i--)
349 if (field_is_static (&TYPE_FIELD (type, i)))
351 gen_static_field (gdbarch, ax, &value, type, i);
352 if (value.optimized_out)
356 case axs_lvalue_memory:
358 int length = TYPE_LENGTH (check_typedef (value.type));
360 ax_const_l (ax, length);
361 ax_simple (ax, aop_trace);
365 case axs_lvalue_register:
366 /* We need to mention the register somewhere in the bytecode,
367 so ax_reqs will pick it up and add it to the mask of
369 ax_reg (ax, value.u.reg);
377 /* Now scan through base classes recursively. */
378 for (i = 0; i < nbases; i++)
380 struct type *basetype = check_typedef (TYPE_BASECLASS (type, i));
382 gen_trace_static_fields (gdbarch, ax, basetype);
386 /* Trace the lvalue on the stack, if it needs it. In either case, pop
387 the value. Useful on the left side of a comma, and at the end of
388 an expression being used for tracing. */
390 gen_traced_pop (struct gdbarch *gdbarch,
391 struct agent_expr *ax, struct axs_value *value)
397 /* We don't trace rvalues, just the lvalues necessary to
398 produce them. So just dispose of this value. */
399 ax_simple (ax, aop_pop);
402 case axs_lvalue_memory:
404 int length = TYPE_LENGTH (check_typedef (value->type));
406 /* There's no point in trying to use a trace_quick bytecode
407 here, since "trace_quick SIZE pop" is three bytes, whereas
408 "const8 SIZE trace" is also three bytes, does the same
409 thing, and the simplest code which generates that will also
410 work correctly for objects with large sizes. */
411 ax_const_l (ax, length);
412 ax_simple (ax, aop_trace);
416 case axs_lvalue_register:
417 /* We need to mention the register somewhere in the bytecode,
418 so ax_reqs will pick it up and add it to the mask of
420 ax_reg (ax, value->u.reg);
421 ax_simple (ax, aop_pop);
425 /* If we're not tracing, just pop the value. */
426 ax_simple (ax, aop_pop);
428 /* To trace C++ classes with static fields stored elsewhere. */
430 && (TYPE_CODE (value->type) == TYPE_CODE_STRUCT
431 || TYPE_CODE (value->type) == TYPE_CODE_UNION))
432 gen_trace_static_fields (gdbarch, ax, value->type);
437 /* Generating bytecode from GDB expressions: helper functions */
439 /* Assume that the lower bits of the top of the stack is a value of
440 type TYPE, and the upper bits are zero. Sign-extend if necessary. */
442 gen_sign_extend (struct agent_expr *ax, struct type *type)
444 /* Do we need to sign-extend this? */
445 if (!TYPE_UNSIGNED (type))
446 ax_ext (ax, TYPE_LENGTH (type) * TARGET_CHAR_BIT);
450 /* Assume the lower bits of the top of the stack hold a value of type
451 TYPE, and the upper bits are garbage. Sign-extend or truncate as
454 gen_extend (struct agent_expr *ax, struct type *type)
456 int bits = TYPE_LENGTH (type) * TARGET_CHAR_BIT;
458 ((TYPE_UNSIGNED (type) ? ax_zero_ext : ax_ext) (ax, bits));
462 /* Assume that the top of the stack contains a value of type "pointer
463 to TYPE"; generate code to fetch its value. Note that TYPE is the
464 target type, not the pointer type. */
466 gen_fetch (struct agent_expr *ax, struct type *type)
470 /* Record the area of memory we're about to fetch. */
471 ax_trace_quick (ax, TYPE_LENGTH (type));
474 switch (TYPE_CODE (type))
481 /* It's a scalar value, so we know how to dereference it. How
482 many bytes long is it? */
483 switch (TYPE_LENGTH (type))
485 case 8 / TARGET_CHAR_BIT:
486 ax_simple (ax, aop_ref8);
488 case 16 / TARGET_CHAR_BIT:
489 ax_simple (ax, aop_ref16);
491 case 32 / TARGET_CHAR_BIT:
492 ax_simple (ax, aop_ref32);
494 case 64 / TARGET_CHAR_BIT:
495 ax_simple (ax, aop_ref64);
498 /* Either our caller shouldn't have asked us to dereference
499 that pointer (other code's fault), or we're not
500 implementing something we should be (this code's fault).
501 In any case, it's a bug the user shouldn't see. */
503 internal_error (__FILE__, __LINE__,
504 _("gen_fetch: strange size"));
507 gen_sign_extend (ax, type);
511 /* Either our caller shouldn't have asked us to dereference that
512 pointer (other code's fault), or we're not implementing
513 something we should be (this code's fault). In any case,
514 it's a bug the user shouldn't see. */
515 internal_error (__FILE__, __LINE__,
516 _("gen_fetch: bad type code"));
521 /* Generate code to left shift the top of the stack by DISTANCE bits, or
522 right shift it by -DISTANCE bits if DISTANCE < 0. This generates
523 unsigned (logical) right shifts. */
525 gen_left_shift (struct agent_expr *ax, int distance)
529 ax_const_l (ax, distance);
530 ax_simple (ax, aop_lsh);
532 else if (distance < 0)
534 ax_const_l (ax, -distance);
535 ax_simple (ax, aop_rsh_unsigned);
541 /* Generating bytecode from GDB expressions: symbol references */
543 /* Generate code to push the base address of the argument portion of
544 the top stack frame. */
546 gen_frame_args_address (struct gdbarch *gdbarch, struct agent_expr *ax)
549 LONGEST frame_offset;
551 gdbarch_virtual_frame_pointer (gdbarch,
552 ax->scope, &frame_reg, &frame_offset);
553 ax_reg (ax, frame_reg);
554 gen_offset (ax, frame_offset);
558 /* Generate code to push the base address of the locals portion of the
561 gen_frame_locals_address (struct gdbarch *gdbarch, struct agent_expr *ax)
564 LONGEST frame_offset;
566 gdbarch_virtual_frame_pointer (gdbarch,
567 ax->scope, &frame_reg, &frame_offset);
568 ax_reg (ax, frame_reg);
569 gen_offset (ax, frame_offset);
573 /* Generate code to add OFFSET to the top of the stack. Try to
574 generate short and readable code. We use this for getting to
575 variables on the stack, and structure members. If we were
576 programming in ML, it would be clearer why these are the same
579 gen_offset (struct agent_expr *ax, int offset)
581 /* It would suffice to simply push the offset and add it, but this
582 makes it easier to read positive and negative offsets in the
586 ax_const_l (ax, offset);
587 ax_simple (ax, aop_add);
591 ax_const_l (ax, -offset);
592 ax_simple (ax, aop_sub);
597 /* In many cases, a symbol's value is the offset from some other
598 address (stack frame, base register, etc.) Generate code to add
599 VAR's value to the top of the stack. */
601 gen_sym_offset (struct agent_expr *ax, struct symbol *var)
603 gen_offset (ax, SYMBOL_VALUE (var));
607 /* Generate code for a variable reference to AX. The variable is the
608 symbol VAR. Set VALUE to describe the result. */
611 gen_var_ref (struct gdbarch *gdbarch, struct agent_expr *ax,
612 struct axs_value *value, struct symbol *var)
614 /* Dereference any typedefs. */
615 value->type = check_typedef (SYMBOL_TYPE (var));
616 value->optimized_out = 0;
618 /* I'm imitating the code in read_var_value. */
619 switch (SYMBOL_CLASS (var))
621 case LOC_CONST: /* A constant, like an enum value. */
622 ax_const_l (ax, (LONGEST) SYMBOL_VALUE (var));
623 value->kind = axs_rvalue;
626 case LOC_LABEL: /* A goto label, being used as a value. */
627 ax_const_l (ax, (LONGEST) SYMBOL_VALUE_ADDRESS (var));
628 value->kind = axs_rvalue;
631 case LOC_CONST_BYTES:
632 internal_error (__FILE__, __LINE__,
633 _("gen_var_ref: LOC_CONST_BYTES symbols are not supported"));
635 /* Variable at a fixed location in memory. Easy. */
637 /* Push the address of the variable. */
638 ax_const_l (ax, SYMBOL_VALUE_ADDRESS (var));
639 value->kind = axs_lvalue_memory;
642 case LOC_ARG: /* var lives in argument area of frame */
643 gen_frame_args_address (gdbarch, ax);
644 gen_sym_offset (ax, var);
645 value->kind = axs_lvalue_memory;
648 case LOC_REF_ARG: /* As above, but the frame slot really
649 holds the address of the variable. */
650 gen_frame_args_address (gdbarch, ax);
651 gen_sym_offset (ax, var);
652 /* Don't assume any particular pointer size. */
653 gen_fetch (ax, builtin_type (gdbarch)->builtin_data_ptr);
654 value->kind = axs_lvalue_memory;
657 case LOC_LOCAL: /* var lives in locals area of frame */
658 gen_frame_locals_address (gdbarch, ax);
659 gen_sym_offset (ax, var);
660 value->kind = axs_lvalue_memory;
664 error (_("Cannot compute value of typedef `%s'."),
665 SYMBOL_PRINT_NAME (var));
669 ax_const_l (ax, BLOCK_START (SYMBOL_BLOCK_VALUE (var)));
670 value->kind = axs_rvalue;
674 /* Don't generate any code at all; in the process of treating
675 this as an lvalue or rvalue, the caller will generate the
677 value->kind = axs_lvalue_register;
678 value->u.reg = SYMBOL_REGISTER_OPS (var)->register_number (var, gdbarch);
681 /* A lot like LOC_REF_ARG, but the pointer lives directly in a
682 register, not on the stack. Simpler than LOC_REGISTER
683 because it's just like any other case where the thing
684 has a real address. */
685 case LOC_REGPARM_ADDR:
686 ax_reg (ax, SYMBOL_REGISTER_OPS (var)->register_number (var, gdbarch));
687 value->kind = axs_lvalue_memory;
692 struct minimal_symbol *msym
693 = lookup_minimal_symbol (SYMBOL_LINKAGE_NAME (var), NULL, NULL);
695 error (_("Couldn't resolve symbol `%s'."), SYMBOL_PRINT_NAME (var));
697 /* Push the address of the variable. */
698 ax_const_l (ax, SYMBOL_VALUE_ADDRESS (msym));
699 value->kind = axs_lvalue_memory;
704 /* FIXME: cagney/2004-01-26: It should be possible to
705 unconditionally call the SYMBOL_COMPUTED_OPS method when available.
706 Unfortunately DWARF 2 stores the frame-base (instead of the
707 function) location in a function's symbol. Oops! For the
708 moment enable this when/where applicable. */
709 SYMBOL_COMPUTED_OPS (var)->tracepoint_var_ref (var, gdbarch, ax, value);
712 case LOC_OPTIMIZED_OUT:
713 /* Flag this, but don't say anything; leave it up to callers to
715 value->optimized_out = 1;
719 error (_("Cannot find value of botched symbol `%s'."),
720 SYMBOL_PRINT_NAME (var));
727 /* Generating bytecode from GDB expressions: literals */
730 gen_int_literal (struct agent_expr *ax, struct axs_value *value, LONGEST k,
734 value->kind = axs_rvalue;
735 value->type = check_typedef (type);
740 /* Generating bytecode from GDB expressions: unary conversions, casts */
742 /* Take what's on the top of the stack (as described by VALUE), and
743 try to make an rvalue out of it. Signal an error if we can't do
746 require_rvalue (struct agent_expr *ax, struct axs_value *value)
751 /* It's already an rvalue. */
754 case axs_lvalue_memory:
755 /* The top of stack is the address of the object. Dereference. */
756 gen_fetch (ax, value->type);
759 case axs_lvalue_register:
760 /* There's nothing on the stack, but value->u.reg is the
761 register number containing the value.
763 When we add floating-point support, this is going to have to
764 change. What about SPARC register pairs, for example? */
765 ax_reg (ax, value->u.reg);
766 gen_extend (ax, value->type);
770 value->kind = axs_rvalue;
774 /* Assume the top of the stack is described by VALUE, and perform the
775 usual unary conversions. This is motivated by ANSI 6.2.2, but of
776 course GDB expressions are not ANSI; they're the mishmash union of
777 a bunch of languages. Rah.
779 NOTE! This function promises to produce an rvalue only when the
780 incoming value is of an appropriate type. In other words, the
781 consumer of the value this function produces may assume the value
782 is an rvalue only after checking its type.
784 The immediate issue is that if the user tries to use a structure or
785 union as an operand of, say, the `+' operator, we don't want to try
786 to convert that structure to an rvalue; require_rvalue will bomb on
787 structs and unions. Rather, we want to simply pass the struct
788 lvalue through unchanged, and let `+' raise an error. */
791 gen_usual_unary (struct expression *exp, struct agent_expr *ax,
792 struct axs_value *value)
794 /* We don't have to generate any code for the usual integral
795 conversions, since values are always represented as full-width on
796 the stack. Should we tweak the type? */
798 /* Some types require special handling. */
799 switch (TYPE_CODE (value->type))
801 /* Functions get converted to a pointer to the function. */
803 value->type = lookup_pointer_type (value->type);
804 value->kind = axs_rvalue; /* Should always be true, but just in case. */
807 /* Arrays get converted to a pointer to their first element, and
808 are no longer an lvalue. */
809 case TYPE_CODE_ARRAY:
811 struct type *elements = TYPE_TARGET_TYPE (value->type);
812 value->type = lookup_pointer_type (elements);
813 value->kind = axs_rvalue;
814 /* We don't need to generate any code; the address of the array
815 is also the address of its first element. */
819 /* Don't try to convert structures and unions to rvalues. Let the
820 consumer signal an error. */
821 case TYPE_CODE_STRUCT:
822 case TYPE_CODE_UNION:
825 /* If the value is an enum, call it an integer. */
827 value->type = builtin_type (exp->gdbarch)->builtin_int;
831 /* If the value is an lvalue, dereference it. */
832 require_rvalue (ax, value);
836 /* Return non-zero iff the type TYPE1 is considered "wider" than the
837 type TYPE2, according to the rules described in gen_usual_arithmetic. */
839 type_wider_than (struct type *type1, struct type *type2)
841 return (TYPE_LENGTH (type1) > TYPE_LENGTH (type2)
842 || (TYPE_LENGTH (type1) == TYPE_LENGTH (type2)
843 && TYPE_UNSIGNED (type1)
844 && !TYPE_UNSIGNED (type2)));
848 /* Return the "wider" of the two types TYPE1 and TYPE2. */
850 max_type (struct type *type1, struct type *type2)
852 return type_wider_than (type1, type2) ? type1 : type2;
856 /* Generate code to convert a scalar value of type FROM to type TO. */
858 gen_conversion (struct agent_expr *ax, struct type *from, struct type *to)
860 /* Perhaps there is a more graceful way to state these rules. */
862 /* If we're converting to a narrower type, then we need to clear out
864 if (TYPE_LENGTH (to) < TYPE_LENGTH (from))
865 gen_extend (ax, from);
867 /* If the two values have equal width, but different signednesses,
868 then we need to extend. */
869 else if (TYPE_LENGTH (to) == TYPE_LENGTH (from))
871 if (TYPE_UNSIGNED (from) != TYPE_UNSIGNED (to))
875 /* If we're converting to a wider type, and becoming unsigned, then
876 we need to zero out any possible sign bits. */
877 else if (TYPE_LENGTH (to) > TYPE_LENGTH (from))
879 if (TYPE_UNSIGNED (to))
885 /* Return non-zero iff the type FROM will require any bytecodes to be
886 emitted to be converted to the type TO. */
888 is_nontrivial_conversion (struct type *from, struct type *to)
890 struct agent_expr *ax = new_agent_expr (0);
893 /* Actually generate the code, and see if anything came out. At the
894 moment, it would be trivial to replicate the code in
895 gen_conversion here, but in the future, when we're supporting
896 floating point and the like, it may not be. Doing things this
897 way allows this function to be independent of the logic in
899 gen_conversion (ax, from, to);
900 nontrivial = ax->len > 0;
901 free_agent_expr (ax);
906 /* Generate code to perform the "usual arithmetic conversions" (ANSI C
907 6.2.1.5) for the two operands of an arithmetic operator. This
908 effectively finds a "least upper bound" type for the two arguments,
909 and promotes each argument to that type. *VALUE1 and *VALUE2
910 describe the values as they are passed in, and as they are left. */
912 gen_usual_arithmetic (struct expression *exp, struct agent_expr *ax,
913 struct axs_value *value1, struct axs_value *value2)
915 /* Do the usual binary conversions. */
916 if (TYPE_CODE (value1->type) == TYPE_CODE_INT
917 && TYPE_CODE (value2->type) == TYPE_CODE_INT)
919 /* The ANSI integral promotions seem to work this way: Order the
920 integer types by size, and then by signedness: an n-bit
921 unsigned type is considered "wider" than an n-bit signed
922 type. Promote to the "wider" of the two types, and always
923 promote at least to int. */
924 struct type *target = max_type (builtin_type (exp->gdbarch)->builtin_int,
925 max_type (value1->type, value2->type));
927 /* Deal with value2, on the top of the stack. */
928 gen_conversion (ax, value2->type, target);
930 /* Deal with value1, not on the top of the stack. Don't
931 generate the `swap' instructions if we're not actually going
933 if (is_nontrivial_conversion (value1->type, target))
935 ax_simple (ax, aop_swap);
936 gen_conversion (ax, value1->type, target);
937 ax_simple (ax, aop_swap);
940 value1->type = value2->type = check_typedef (target);
945 /* Generate code to perform the integral promotions (ANSI 6.2.1.1) on
946 the value on the top of the stack, as described by VALUE. Assume
947 the value has integral type. */
949 gen_integral_promotions (struct expression *exp, struct agent_expr *ax,
950 struct axs_value *value)
952 const struct builtin_type *builtin = builtin_type (exp->gdbarch);
954 if (!type_wider_than (value->type, builtin->builtin_int))
956 gen_conversion (ax, value->type, builtin->builtin_int);
957 value->type = builtin->builtin_int;
959 else if (!type_wider_than (value->type, builtin->builtin_unsigned_int))
961 gen_conversion (ax, value->type, builtin->builtin_unsigned_int);
962 value->type = builtin->builtin_unsigned_int;
967 /* Generate code for a cast to TYPE. */
969 gen_cast (struct agent_expr *ax, struct axs_value *value, struct type *type)
971 /* GCC does allow casts to yield lvalues, so this should be fixed
972 before merging these changes into the trunk. */
973 require_rvalue (ax, value);
974 /* Dereference typedefs. */
975 type = check_typedef (type);
977 switch (TYPE_CODE (type))
981 /* It's implementation-defined, and I'll bet this is what GCC
985 case TYPE_CODE_ARRAY:
986 case TYPE_CODE_STRUCT:
987 case TYPE_CODE_UNION:
989 error (_("Invalid type cast: intended type must be scalar."));
992 /* We don't have to worry about the size of the value, because
993 all our integral values are fully sign-extended, and when
994 casting pointers we can do anything we like. Is there any
995 way for us to know what GCC actually does with a cast like
1000 gen_conversion (ax, value->type, type);
1003 case TYPE_CODE_VOID:
1004 /* We could pop the value, and rely on everyone else to check
1005 the type and notice that this value doesn't occupy a stack
1006 slot. But for now, leave the value on the stack, and
1007 preserve the "value == stack element" assumption. */
1011 error (_("Casts to requested type are not yet implemented."));
1019 /* Generating bytecode from GDB expressions: arithmetic */
1021 /* Scale the integer on the top of the stack by the size of the target
1022 of the pointer type TYPE. */
1024 gen_scale (struct agent_expr *ax, enum agent_op op, struct type *type)
1026 struct type *element = TYPE_TARGET_TYPE (type);
1028 if (TYPE_LENGTH (element) != 1)
1030 ax_const_l (ax, TYPE_LENGTH (element));
1036 /* Generate code for pointer arithmetic PTR + INT. */
1038 gen_ptradd (struct agent_expr *ax, struct axs_value *value,
1039 struct axs_value *value1, struct axs_value *value2)
1041 gdb_assert (pointer_type (value1->type));
1042 gdb_assert (TYPE_CODE (value2->type) == TYPE_CODE_INT);
1044 gen_scale (ax, aop_mul, value1->type);
1045 ax_simple (ax, aop_add);
1046 gen_extend (ax, value1->type); /* Catch overflow. */
1047 value->type = value1->type;
1048 value->kind = axs_rvalue;
1052 /* Generate code for pointer arithmetic PTR - INT. */
1054 gen_ptrsub (struct agent_expr *ax, struct axs_value *value,
1055 struct axs_value *value1, struct axs_value *value2)
1057 gdb_assert (pointer_type (value1->type));
1058 gdb_assert (TYPE_CODE (value2->type) == TYPE_CODE_INT);
1060 gen_scale (ax, aop_mul, value1->type);
1061 ax_simple (ax, aop_sub);
1062 gen_extend (ax, value1->type); /* Catch overflow. */
1063 value->type = value1->type;
1064 value->kind = axs_rvalue;
1068 /* Generate code for pointer arithmetic PTR - PTR. */
1070 gen_ptrdiff (struct agent_expr *ax, struct axs_value *value,
1071 struct axs_value *value1, struct axs_value *value2,
1072 struct type *result_type)
1074 gdb_assert (pointer_type (value1->type));
1075 gdb_assert (pointer_type (value2->type));
1077 if (TYPE_LENGTH (TYPE_TARGET_TYPE (value1->type))
1078 != TYPE_LENGTH (TYPE_TARGET_TYPE (value2->type)))
1080 First argument of `-' is a pointer, but second argument is neither\n\
1081 an integer nor a pointer of the same type."));
1083 ax_simple (ax, aop_sub);
1084 gen_scale (ax, aop_div_unsigned, value1->type);
1085 value->type = result_type;
1086 value->kind = axs_rvalue;
1090 /* Generate code for a binary operator that doesn't do pointer magic.
1091 We set VALUE to describe the result value; we assume VALUE1 and
1092 VALUE2 describe the two operands, and that they've undergone the
1093 usual binary conversions. MAY_CARRY should be non-zero iff the
1094 result needs to be extended. NAME is the English name of the
1095 operator, used in error messages */
1097 gen_binop (struct agent_expr *ax, struct axs_value *value,
1098 struct axs_value *value1, struct axs_value *value2, enum agent_op op,
1099 enum agent_op op_unsigned, int may_carry, char *name)
1101 /* We only handle INT op INT. */
1102 if ((TYPE_CODE (value1->type) != TYPE_CODE_INT)
1103 || (TYPE_CODE (value2->type) != TYPE_CODE_INT))
1104 error (_("Invalid combination of types in %s."), name);
1107 TYPE_UNSIGNED (value1->type) ? op_unsigned : op);
1109 gen_extend (ax, value1->type); /* catch overflow */
1110 value->type = value1->type;
1111 value->kind = axs_rvalue;
1116 gen_logical_not (struct agent_expr *ax, struct axs_value *value,
1117 struct type *result_type)
1119 if (TYPE_CODE (value->type) != TYPE_CODE_INT
1120 && TYPE_CODE (value->type) != TYPE_CODE_PTR)
1121 error (_("Invalid type of operand to `!'."));
1123 ax_simple (ax, aop_log_not);
1124 value->type = result_type;
1129 gen_complement (struct agent_expr *ax, struct axs_value *value)
1131 if (TYPE_CODE (value->type) != TYPE_CODE_INT)
1132 error (_("Invalid type of operand to `~'."));
1134 ax_simple (ax, aop_bit_not);
1135 gen_extend (ax, value->type);
1140 /* Generating bytecode from GDB expressions: * & . -> @ sizeof */
1142 /* Dereference the value on the top of the stack. */
1144 gen_deref (struct agent_expr *ax, struct axs_value *value)
1146 /* The caller should check the type, because several operators use
1147 this, and we don't know what error message to generate. */
1148 if (!pointer_type (value->type))
1149 internal_error (__FILE__, __LINE__,
1150 _("gen_deref: expected a pointer"));
1152 /* We've got an rvalue now, which is a pointer. We want to yield an
1153 lvalue, whose address is exactly that pointer. So we don't
1154 actually emit any code; we just change the type from "Pointer to
1155 T" to "T", and mark the value as an lvalue in memory. Leave it
1156 to the consumer to actually dereference it. */
1157 value->type = check_typedef (TYPE_TARGET_TYPE (value->type));
1158 if (TYPE_CODE (value->type) == TYPE_CODE_VOID)
1159 error (_("Attempt to dereference a generic pointer."));
1160 value->kind = ((TYPE_CODE (value->type) == TYPE_CODE_FUNC)
1161 ? axs_rvalue : axs_lvalue_memory);
1165 /* Produce the address of the lvalue on the top of the stack. */
1167 gen_address_of (struct agent_expr *ax, struct axs_value *value)
1169 /* Special case for taking the address of a function. The ANSI
1170 standard describes this as a special case, too, so this
1171 arrangement is not without motivation. */
1172 if (TYPE_CODE (value->type) == TYPE_CODE_FUNC)
1173 /* The value's already an rvalue on the stack, so we just need to
1175 value->type = lookup_pointer_type (value->type);
1177 switch (value->kind)
1180 error (_("Operand of `&' is an rvalue, which has no address."));
1182 case axs_lvalue_register:
1183 error (_("Operand of `&' is in a register, and has no address."));
1185 case axs_lvalue_memory:
1186 value->kind = axs_rvalue;
1187 value->type = lookup_pointer_type (value->type);
1192 /* Generate code to push the value of a bitfield of a structure whose
1193 address is on the top of the stack. START and END give the
1194 starting and one-past-ending *bit* numbers of the field within the
1197 gen_bitfield_ref (struct expression *exp, struct agent_expr *ax,
1198 struct axs_value *value, struct type *type,
1201 /* Note that ops[i] fetches 8 << i bits. */
1202 static enum agent_op ops[]
1204 {aop_ref8, aop_ref16, aop_ref32, aop_ref64};
1205 static int num_ops = (sizeof (ops) / sizeof (ops[0]));
1207 /* We don't want to touch any byte that the bitfield doesn't
1208 actually occupy; we shouldn't make any accesses we're not
1209 explicitly permitted to. We rely here on the fact that the
1210 bytecode `ref' operators work on unaligned addresses.
1212 It takes some fancy footwork to get the stack to work the way
1213 we'd like. Say we're retrieving a bitfield that requires three
1214 fetches. Initially, the stack just contains the address:
1216 For the first fetch, we duplicate the address
1218 then add the byte offset, do the fetch, and shift and mask as
1219 needed, yielding a fragment of the value, properly aligned for
1220 the final bitwise or:
1222 then we swap, and repeat the process:
1223 frag1 addr --- address on top
1224 frag1 addr addr --- duplicate it
1225 frag1 addr frag2 --- get second fragment
1226 frag1 frag2 addr --- swap again
1227 frag1 frag2 frag3 --- get third fragment
1228 Notice that, since the third fragment is the last one, we don't
1229 bother duplicating the address this time. Now we have all the
1230 fragments on the stack, and we can simply `or' them together,
1231 yielding the final value of the bitfield. */
1233 /* The first and one-after-last bits in the field, but rounded down
1234 and up to byte boundaries. */
1235 int bound_start = (start / TARGET_CHAR_BIT) * TARGET_CHAR_BIT;
1236 int bound_end = (((end + TARGET_CHAR_BIT - 1)
1240 /* current bit offset within the structure */
1243 /* The index in ops of the opcode we're considering. */
1246 /* The number of fragments we generated in the process. Probably
1247 equal to the number of `one' bits in bytesize, but who cares? */
1250 /* Dereference any typedefs. */
1251 type = check_typedef (type);
1253 /* Can we fetch the number of bits requested at all? */
1254 if ((end - start) > ((1 << num_ops) * 8))
1255 internal_error (__FILE__, __LINE__,
1256 _("gen_bitfield_ref: bitfield too wide"));
1258 /* Note that we know here that we only need to try each opcode once.
1259 That may not be true on machines with weird byte sizes. */
1260 offset = bound_start;
1262 for (op = num_ops - 1; op >= 0; op--)
1264 /* number of bits that ops[op] would fetch */
1265 int op_size = 8 << op;
1267 /* The stack at this point, from bottom to top, contains zero or
1268 more fragments, then the address. */
1270 /* Does this fetch fit within the bitfield? */
1271 if (offset + op_size <= bound_end)
1273 /* Is this the last fragment? */
1274 int last_frag = (offset + op_size == bound_end);
1277 ax_simple (ax, aop_dup); /* keep a copy of the address */
1279 /* Add the offset. */
1280 gen_offset (ax, offset / TARGET_CHAR_BIT);
1284 /* Record the area of memory we're about to fetch. */
1285 ax_trace_quick (ax, op_size / TARGET_CHAR_BIT);
1288 /* Perform the fetch. */
1289 ax_simple (ax, ops[op]);
1291 /* Shift the bits we have to their proper position.
1292 gen_left_shift will generate right shifts when the operand
1295 A big-endian field diagram to ponder:
1296 byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 byte 6 byte 7
1297 +------++------++------++------++------++------++------++------+
1298 xxxxAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBCCCCCxxxxxxxxxxx
1300 bit number 16 32 48 53
1301 These are bit numbers as supplied by GDB. Note that the
1302 bit numbers run from right to left once you've fetched the
1305 A little-endian field diagram to ponder:
1306 byte 7 byte 6 byte 5 byte 4 byte 3 byte 2 byte 1 byte 0
1307 +------++------++------++------++------++------++------++------+
1308 xxxxxxxxxxxAAAAABBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCCCCCCCCCCCxxxx
1310 bit number 48 32 16 4 0
1312 In both cases, the most significant end is on the left
1313 (i.e. normal numeric writing order), which means that you
1314 don't go crazy thinking about `left' and `right' shifts.
1316 We don't have to worry about masking yet:
1317 - If they contain garbage off the least significant end, then we
1318 must be looking at the low end of the field, and the right
1319 shift will wipe them out.
1320 - If they contain garbage off the most significant end, then we
1321 must be looking at the most significant end of the word, and
1322 the sign/zero extension will wipe them out.
1323 - If we're in the interior of the word, then there is no garbage
1324 on either end, because the ref operators zero-extend. */
1325 if (gdbarch_byte_order (exp->gdbarch) == BFD_ENDIAN_BIG)
1326 gen_left_shift (ax, end - (offset + op_size));
1328 gen_left_shift (ax, offset - start);
1331 /* Bring the copy of the address up to the top. */
1332 ax_simple (ax, aop_swap);
1339 /* Generate enough bitwise `or' operations to combine all the
1340 fragments we left on the stack. */
1341 while (fragment_count-- > 1)
1342 ax_simple (ax, aop_bit_or);
1344 /* Sign- or zero-extend the value as appropriate. */
1345 ((TYPE_UNSIGNED (type) ? ax_zero_ext : ax_ext) (ax, end - start));
1347 /* This is *not* an lvalue. Ugh. */
1348 value->kind = axs_rvalue;
1352 /* Generate bytecodes for field number FIELDNO of type TYPE. OFFSET
1353 is an accumulated offset (in bytes), will be nonzero for objects
1354 embedded in other objects, like C++ base classes. Behavior should
1355 generally follow value_primitive_field. */
1358 gen_primitive_field (struct expression *exp,
1359 struct agent_expr *ax, struct axs_value *value,
1360 int offset, int fieldno, struct type *type)
1362 /* Is this a bitfield? */
1363 if (TYPE_FIELD_PACKED (type, fieldno))
1364 gen_bitfield_ref (exp, ax, value, TYPE_FIELD_TYPE (type, fieldno),
1365 (offset * TARGET_CHAR_BIT
1366 + TYPE_FIELD_BITPOS (type, fieldno)),
1367 (offset * TARGET_CHAR_BIT
1368 + TYPE_FIELD_BITPOS (type, fieldno)
1369 + TYPE_FIELD_BITSIZE (type, fieldno)));
1372 gen_offset (ax, offset
1373 + TYPE_FIELD_BITPOS (type, fieldno) / TARGET_CHAR_BIT);
1374 value->kind = axs_lvalue_memory;
1375 value->type = TYPE_FIELD_TYPE (type, fieldno);
1379 /* Search for the given field in either the given type or one of its
1380 base classes. Return 1 if found, 0 if not. */
1383 gen_struct_ref_recursive (struct expression *exp, struct agent_expr *ax,
1384 struct axs_value *value,
1385 char *field, int offset, struct type *type)
1388 int nbases = TYPE_N_BASECLASSES (type);
1390 CHECK_TYPEDEF (type);
1392 for (i = TYPE_NFIELDS (type) - 1; i >= nbases; i--)
1394 char *this_name = TYPE_FIELD_NAME (type, i);
1398 if (strcmp (field, this_name) == 0)
1400 /* Note that bytecodes for the struct's base (aka
1401 "this") will have been generated already, which will
1402 be unnecessary but not harmful if the static field is
1403 being handled as a global. */
1404 if (field_is_static (&TYPE_FIELD (type, i)))
1406 gen_static_field (exp->gdbarch, ax, value, type, i);
1407 if (value->optimized_out)
1408 error (_("static field `%s' has been optimized out, cannot use"),
1413 gen_primitive_field (exp, ax, value, offset, i, type);
1416 #if 0 /* is this right? */
1417 if (this_name[0] == '\0')
1418 internal_error (__FILE__, __LINE__,
1419 _("find_field: anonymous unions not supported"));
1424 /* Now scan through base classes recursively. */
1425 for (i = 0; i < nbases; i++)
1427 struct type *basetype = check_typedef (TYPE_BASECLASS (type, i));
1429 rslt = gen_struct_ref_recursive (exp, ax, value, field,
1430 offset + TYPE_BASECLASS_BITPOS (type, i) / TARGET_CHAR_BIT,
1436 /* Not found anywhere, flag so caller can complain. */
1440 /* Generate code to reference the member named FIELD of a structure or
1441 union. The top of the stack, as described by VALUE, should have
1442 type (pointer to a)* struct/union. OPERATOR_NAME is the name of
1443 the operator being compiled, and OPERAND_NAME is the kind of thing
1444 it operates on; we use them in error messages. */
1446 gen_struct_ref (struct expression *exp, struct agent_expr *ax,
1447 struct axs_value *value, char *field,
1448 char *operator_name, char *operand_name)
1453 /* Follow pointers until we reach a non-pointer. These aren't the C
1454 semantics, but they're what the normal GDB evaluator does, so we
1455 should at least be consistent. */
1456 while (pointer_type (value->type))
1458 require_rvalue (ax, value);
1459 gen_deref (ax, value);
1461 type = check_typedef (value->type);
1463 /* This must yield a structure or a union. */
1464 if (TYPE_CODE (type) != TYPE_CODE_STRUCT
1465 && TYPE_CODE (type) != TYPE_CODE_UNION)
1466 error (_("The left operand of `%s' is not a %s."),
1467 operator_name, operand_name);
1469 /* And it must be in memory; we don't deal with structure rvalues,
1470 or structures living in registers. */
1471 if (value->kind != axs_lvalue_memory)
1472 error (_("Structure does not live in memory."));
1474 /* Search through fields and base classes recursively. */
1475 found = gen_struct_ref_recursive (exp, ax, value, field, 0, type);
1478 error (_("Couldn't find member named `%s' in struct/union/class `%s'"),
1479 field, TYPE_TAG_NAME (type));
1483 gen_namespace_elt (struct expression *exp,
1484 struct agent_expr *ax, struct axs_value *value,
1485 const struct type *curtype, char *name);
1487 gen_maybe_namespace_elt (struct expression *exp,
1488 struct agent_expr *ax, struct axs_value *value,
1489 const struct type *curtype, char *name);
1492 gen_static_field (struct gdbarch *gdbarch,
1493 struct agent_expr *ax, struct axs_value *value,
1494 struct type *type, int fieldno)
1496 if (TYPE_FIELD_LOC_KIND (type, fieldno) == FIELD_LOC_KIND_PHYSADDR)
1498 ax_const_l (ax, TYPE_FIELD_STATIC_PHYSADDR (type, fieldno));
1499 value->kind = axs_lvalue_memory;
1500 value->type = TYPE_FIELD_TYPE (type, fieldno);
1501 value->optimized_out = 0;
1505 char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno);
1506 struct symbol *sym = lookup_symbol (phys_name, 0, VAR_DOMAIN, 0);
1510 gen_var_ref (gdbarch, ax, value, sym);
1512 /* Don't error if the value was optimized out, we may be
1513 scanning all static fields and just want to pass over this
1514 and continue with the rest. */
1518 /* Silently assume this was optimized out; class printing
1519 will let the user know why the data is missing. */
1520 value->optimized_out = 1;
1526 gen_struct_elt_for_reference (struct expression *exp,
1527 struct agent_expr *ax, struct axs_value *value,
1528 struct type *type, char *fieldname)
1530 struct type *t = type;
1532 struct value *v, *result;
1534 if (TYPE_CODE (t) != TYPE_CODE_STRUCT
1535 && TYPE_CODE (t) != TYPE_CODE_UNION)
1536 internal_error (__FILE__, __LINE__,
1537 _("non-aggregate type to gen_struct_elt_for_reference"));
1539 for (i = TYPE_NFIELDS (t) - 1; i >= TYPE_N_BASECLASSES (t); i--)
1541 char *t_field_name = TYPE_FIELD_NAME (t, i);
1543 if (t_field_name && strcmp (t_field_name, fieldname) == 0)
1545 if (field_is_static (&TYPE_FIELD (t, i)))
1547 gen_static_field (exp->gdbarch, ax, value, t, i);
1548 if (value->optimized_out)
1549 error (_("static field `%s' has been optimized out, cannot use"),
1553 if (TYPE_FIELD_PACKED (t, i))
1554 error (_("pointers to bitfield members not allowed"));
1556 /* FIXME we need a way to do "want_address" equivalent */
1558 error (_("Cannot reference non-static field \"%s\""), fieldname);
1562 /* FIXME add other scoped-reference cases here */
1564 /* Do a last-ditch lookup. */
1565 return gen_maybe_namespace_elt (exp, ax, value, type, fieldname);
1568 /* C++: Return the member NAME of the namespace given by the type
1572 gen_namespace_elt (struct expression *exp,
1573 struct agent_expr *ax, struct axs_value *value,
1574 const struct type *curtype, char *name)
1576 int found = gen_maybe_namespace_elt (exp, ax, value, curtype, name);
1579 error (_("No symbol \"%s\" in namespace \"%s\"."),
1580 name, TYPE_TAG_NAME (curtype));
1585 /* A helper function used by value_namespace_elt and
1586 value_struct_elt_for_reference. It looks up NAME inside the
1587 context CURTYPE; this works if CURTYPE is a namespace or if CURTYPE
1588 is a class and NAME refers to a type in CURTYPE itself (as opposed
1589 to, say, some base class of CURTYPE). */
1592 gen_maybe_namespace_elt (struct expression *exp,
1593 struct agent_expr *ax, struct axs_value *value,
1594 const struct type *curtype, char *name)
1596 const char *namespace_name = TYPE_TAG_NAME (curtype);
1599 sym = cp_lookup_symbol_namespace (namespace_name, name,
1600 block_for_pc (ax->scope),
1606 gen_var_ref (exp->gdbarch, ax, value, sym);
1608 if (value->optimized_out)
1609 error (_("`%s' has been optimized out, cannot use"),
1610 SYMBOL_PRINT_NAME (sym));
1617 gen_aggregate_elt_ref (struct expression *exp,
1618 struct agent_expr *ax, struct axs_value *value,
1619 struct type *type, char *field,
1620 char *operator_name, char *operand_name)
1622 switch (TYPE_CODE (type))
1624 case TYPE_CODE_STRUCT:
1625 case TYPE_CODE_UNION:
1626 return gen_struct_elt_for_reference (exp, ax, value, type, field);
1628 case TYPE_CODE_NAMESPACE:
1629 return gen_namespace_elt (exp, ax, value, type, field);
1632 internal_error (__FILE__, __LINE__,
1633 _("non-aggregate type in gen_aggregate_elt_ref"));
1639 /* Generate code for GDB's magical `repeat' operator.
1640 LVALUE @ INT creates an array INT elements long, and whose elements
1641 have the same type as LVALUE, located in memory so that LVALUE is
1642 its first element. For example, argv[0]@argc gives you the array
1643 of command-line arguments.
1645 Unfortunately, because we have to know the types before we actually
1646 have a value for the expression, we can't implement this perfectly
1647 without changing the type system, having values that occupy two
1648 stack slots, doing weird things with sizeof, etc. So we require
1649 the right operand to be a constant expression. */
1651 gen_repeat (struct expression *exp, union exp_element **pc,
1652 struct agent_expr *ax, struct axs_value *value)
1654 struct axs_value value1;
1655 /* We don't want to turn this into an rvalue, so no conversions
1657 gen_expr (exp, pc, ax, &value1);
1658 if (value1.kind != axs_lvalue_memory)
1659 error (_("Left operand of `@' must be an object in memory."));
1661 /* Evaluate the length; it had better be a constant. */
1663 struct value *v = const_expr (pc);
1667 error (_("Right operand of `@' must be a constant, in agent expressions."));
1668 if (TYPE_CODE (value_type (v)) != TYPE_CODE_INT)
1669 error (_("Right operand of `@' must be an integer."));
1670 length = value_as_long (v);
1672 error (_("Right operand of `@' must be positive."));
1674 /* The top of the stack is already the address of the object, so
1675 all we need to do is frob the type of the lvalue. */
1677 /* FIXME-type-allocation: need a way to free this type when we are
1680 = lookup_array_range_type (value1.type, 0, length - 1);
1682 value->kind = axs_lvalue_memory;
1683 value->type = array;
1689 /* Emit code for the `sizeof' operator.
1690 *PC should point at the start of the operand expression; we advance it
1691 to the first instruction after the operand. */
1693 gen_sizeof (struct expression *exp, union exp_element **pc,
1694 struct agent_expr *ax, struct axs_value *value,
1695 struct type *size_type)
1697 /* We don't care about the value of the operand expression; we only
1698 care about its type. However, in the current arrangement, the
1699 only way to find an expression's type is to generate code for it.
1700 So we generate code for the operand, and then throw it away,
1701 replacing it with code that simply pushes its size. */
1702 int start = ax->len;
1703 gen_expr (exp, pc, ax, value);
1705 /* Throw away the code we just generated. */
1708 ax_const_l (ax, TYPE_LENGTH (value->type));
1709 value->kind = axs_rvalue;
1710 value->type = size_type;
1714 /* Generating bytecode from GDB expressions: general recursive thingy */
1717 /* A gen_expr function written by a Gen-X'er guy.
1718 Append code for the subexpression of EXPR starting at *POS_P to AX. */
1720 gen_expr (struct expression *exp, union exp_element **pc,
1721 struct agent_expr *ax, struct axs_value *value)
1723 /* Used to hold the descriptions of operand expressions. */
1724 struct axs_value value1, value2, value3;
1725 enum exp_opcode op = (*pc)[0].opcode, op2;
1726 int if1, go1, if2, go2, end;
1728 /* If we're looking at a constant expression, just push its value. */
1730 struct value *v = maybe_const_expr (pc);
1734 ax_const_l (ax, value_as_long (v));
1735 value->kind = axs_rvalue;
1736 value->type = check_typedef (value_type (v));
1741 /* Otherwise, go ahead and generate code for it. */
1744 /* Binary arithmetic operators. */
1752 case BINOP_SUBSCRIPT:
1753 case BINOP_BITWISE_AND:
1754 case BINOP_BITWISE_IOR:
1755 case BINOP_BITWISE_XOR:
1757 case BINOP_NOTEQUAL:
1763 gen_expr (exp, pc, ax, &value1);
1764 gen_usual_unary (exp, ax, &value1);
1765 gen_expr_binop_rest (exp, op, pc, ax, value, &value1, &value2);
1768 case BINOP_LOGICAL_AND:
1770 /* Generate the obvious sequence of tests and jumps. */
1771 gen_expr (exp, pc, ax, &value1);
1772 gen_usual_unary (exp, ax, &value1);
1773 if1 = ax_goto (ax, aop_if_goto);
1774 go1 = ax_goto (ax, aop_goto);
1775 ax_label (ax, if1, ax->len);
1776 gen_expr (exp, pc, ax, &value2);
1777 gen_usual_unary (exp, ax, &value2);
1778 if2 = ax_goto (ax, aop_if_goto);
1779 go2 = ax_goto (ax, aop_goto);
1780 ax_label (ax, if2, ax->len);
1782 end = ax_goto (ax, aop_goto);
1783 ax_label (ax, go1, ax->len);
1784 ax_label (ax, go2, ax->len);
1786 ax_label (ax, end, ax->len);
1787 value->kind = axs_rvalue;
1788 value->type = language_bool_type (exp->language_defn, exp->gdbarch);
1791 case BINOP_LOGICAL_OR:
1793 /* Generate the obvious sequence of tests and jumps. */
1794 gen_expr (exp, pc, ax, &value1);
1795 gen_usual_unary (exp, ax, &value1);
1796 if1 = ax_goto (ax, aop_if_goto);
1797 gen_expr (exp, pc, ax, &value2);
1798 gen_usual_unary (exp, ax, &value2);
1799 if2 = ax_goto (ax, aop_if_goto);
1801 end = ax_goto (ax, aop_goto);
1802 ax_label (ax, if1, ax->len);
1803 ax_label (ax, if2, ax->len);
1805 ax_label (ax, end, ax->len);
1806 value->kind = axs_rvalue;
1807 value->type = language_bool_type (exp->language_defn, exp->gdbarch);
1812 gen_expr (exp, pc, ax, &value1);
1813 gen_usual_unary (exp, ax, &value1);
1814 /* For (A ? B : C), it's easiest to generate subexpression
1815 bytecodes in order, but if_goto jumps on true, so we invert
1816 the sense of A. Then we can do B by dropping through, and
1818 gen_logical_not (ax, &value1,
1819 language_bool_type (exp->language_defn, exp->gdbarch));
1820 if1 = ax_goto (ax, aop_if_goto);
1821 gen_expr (exp, pc, ax, &value2);
1822 gen_usual_unary (exp, ax, &value2);
1823 end = ax_goto (ax, aop_goto);
1824 ax_label (ax, if1, ax->len);
1825 gen_expr (exp, pc, ax, &value3);
1826 gen_usual_unary (exp, ax, &value3);
1827 ax_label (ax, end, ax->len);
1828 /* This is arbitary - what if B and C are incompatible types? */
1829 value->type = value2.type;
1830 value->kind = value2.kind;
1835 if ((*pc)[0].opcode == OP_INTERNALVAR)
1837 char *name = internalvar_name ((*pc)[1].internalvar);
1838 struct trace_state_variable *tsv;
1840 gen_expr (exp, pc, ax, value);
1841 tsv = find_trace_state_variable (name);
1844 ax_tsv (ax, aop_setv, tsv->number);
1846 ax_tsv (ax, aop_tracev, tsv->number);
1849 error (_("$%s is not a trace state variable, may not assign to it"), name);
1852 error (_("May only assign to trace state variables"));
1855 case BINOP_ASSIGN_MODIFY:
1857 op2 = (*pc)[0].opcode;
1860 if ((*pc)[0].opcode == OP_INTERNALVAR)
1862 char *name = internalvar_name ((*pc)[1].internalvar);
1863 struct trace_state_variable *tsv;
1865 tsv = find_trace_state_variable (name);
1868 /* The tsv will be the left half of the binary operation. */
1869 ax_tsv (ax, aop_getv, tsv->number);
1871 ax_tsv (ax, aop_tracev, tsv->number);
1872 /* Trace state variables are always 64-bit integers. */
1873 value1.kind = axs_rvalue;
1874 value1.type = builtin_type (exp->gdbarch)->builtin_long_long;
1875 /* Now do right half of expression. */
1876 gen_expr_binop_rest (exp, op2, pc, ax, value, &value1, &value2);
1877 /* We have a result of the binary op, set the tsv. */
1878 ax_tsv (ax, aop_setv, tsv->number);
1880 ax_tsv (ax, aop_tracev, tsv->number);
1883 error (_("$%s is not a trace state variable, may not assign to it"), name);
1886 error (_("May only assign to trace state variables"));
1889 /* Note that we need to be a little subtle about generating code
1890 for comma. In C, we can do some optimizations here because
1891 we know the left operand is only being evaluated for effect.
1892 However, if the tracing kludge is in effect, then we always
1893 need to evaluate the left hand side fully, so that all the
1894 variables it mentions get traced. */
1897 gen_expr (exp, pc, ax, &value1);
1898 /* Don't just dispose of the left operand. We might be tracing,
1899 in which case we want to emit code to trace it if it's an
1901 gen_traced_pop (exp->gdbarch, ax, &value1);
1902 gen_expr (exp, pc, ax, value);
1903 /* It's the consumer's responsibility to trace the right operand. */
1906 case OP_LONG: /* some integer constant */
1908 struct type *type = (*pc)[1].type;
1909 LONGEST k = (*pc)[2].longconst;
1911 gen_int_literal (ax, value, k, type);
1916 gen_var_ref (exp->gdbarch, ax, value, (*pc)[2].symbol);
1918 if (value->optimized_out)
1919 error (_("`%s' has been optimized out, cannot use"),
1920 SYMBOL_PRINT_NAME ((*pc)[2].symbol));
1927 const char *name = &(*pc)[2].string;
1929 (*pc) += 4 + BYTES_TO_EXP_ELEM ((*pc)[1].longconst + 1);
1930 reg = user_reg_map_name_to_regnum (exp->gdbarch, name, strlen (name));
1932 internal_error (__FILE__, __LINE__,
1933 _("Register $%s not available"), name);
1934 if (reg >= gdbarch_num_regs (exp->gdbarch))
1935 error (_("'%s' is a pseudo-register; "
1936 "GDB cannot yet trace pseudoregister contents."),
1938 value->kind = axs_lvalue_register;
1940 value->type = register_type (exp->gdbarch, reg);
1944 case OP_INTERNALVAR:
1946 const char *name = internalvar_name ((*pc)[1].internalvar);
1947 struct trace_state_variable *tsv;
1949 tsv = find_trace_state_variable (name);
1952 ax_tsv (ax, aop_getv, tsv->number);
1954 ax_tsv (ax, aop_tracev, tsv->number);
1955 /* Trace state variables are always 64-bit integers. */
1956 value->kind = axs_rvalue;
1957 value->type = builtin_type (exp->gdbarch)->builtin_long_long;
1960 error (_("$%s is not a trace state variable; GDB agent expressions cannot use convenience variables."), name);
1964 /* Weirdo operator: see comments for gen_repeat for details. */
1966 /* Note that gen_repeat handles its own argument evaluation. */
1968 gen_repeat (exp, pc, ax, value);
1973 struct type *type = (*pc)[1].type;
1975 gen_expr (exp, pc, ax, value);
1976 gen_cast (ax, value, type);
1982 struct type *type = check_typedef ((*pc)[1].type);
1984 gen_expr (exp, pc, ax, value);
1985 /* I'm not sure I understand UNOP_MEMVAL entirely. I think
1986 it's just a hack for dealing with minsyms; you take some
1987 integer constant, pretend it's the address of an lvalue of
1988 the given type, and dereference it. */
1989 if (value->kind != axs_rvalue)
1990 /* This would be weird. */
1991 internal_error (__FILE__, __LINE__,
1992 _("gen_expr: OP_MEMVAL operand isn't an rvalue???"));
1994 value->kind = axs_lvalue_memory;
2000 /* + FOO is equivalent to 0 + FOO, which can be optimized. */
2001 gen_expr (exp, pc, ax, value);
2002 gen_usual_unary (exp, ax, value);
2007 /* -FOO is equivalent to 0 - FOO. */
2008 gen_int_literal (ax, &value1, 0,
2009 builtin_type (exp->gdbarch)->builtin_int);
2010 gen_usual_unary (exp, ax, &value1); /* shouldn't do much */
2011 gen_expr (exp, pc, ax, &value2);
2012 gen_usual_unary (exp, ax, &value2);
2013 gen_usual_arithmetic (exp, ax, &value1, &value2);
2014 gen_binop (ax, value, &value1, &value2, aop_sub, aop_sub, 1, "negation");
2017 case UNOP_LOGICAL_NOT:
2019 gen_expr (exp, pc, ax, value);
2020 gen_usual_unary (exp, ax, value);
2021 gen_logical_not (ax, value,
2022 language_bool_type (exp->language_defn, exp->gdbarch));
2025 case UNOP_COMPLEMENT:
2027 gen_expr (exp, pc, ax, value);
2028 gen_usual_unary (exp, ax, value);
2029 gen_integral_promotions (exp, ax, value);
2030 gen_complement (ax, value);
2035 gen_expr (exp, pc, ax, value);
2036 gen_usual_unary (exp, ax, value);
2037 if (!pointer_type (value->type))
2038 error (_("Argument of unary `*' is not a pointer."));
2039 gen_deref (ax, value);
2044 gen_expr (exp, pc, ax, value);
2045 gen_address_of (ax, value);
2050 /* Notice that gen_sizeof handles its own operand, unlike most
2051 of the other unary operator functions. This is because we
2052 have to throw away the code we generate. */
2053 gen_sizeof (exp, pc, ax, value,
2054 builtin_type (exp->gdbarch)->builtin_int);
2057 case STRUCTOP_STRUCT:
2060 int length = (*pc)[1].longconst;
2061 char *name = &(*pc)[2].string;
2063 (*pc) += 4 + BYTES_TO_EXP_ELEM (length + 1);
2064 gen_expr (exp, pc, ax, value);
2065 if (op == STRUCTOP_STRUCT)
2066 gen_struct_ref (exp, ax, value, name, ".", "structure or union");
2067 else if (op == STRUCTOP_PTR)
2068 gen_struct_ref (exp, ax, value, name, "->",
2069 "pointer to a structure or union");
2071 /* If this `if' chain doesn't handle it, then the case list
2072 shouldn't mention it, and we shouldn't be here. */
2073 internal_error (__FILE__, __LINE__,
2074 _("gen_expr: unhandled struct case"));
2081 struct symbol *func, *sym;
2084 func = block_linkage_function (block_for_pc (ax->scope));
2085 this_name = language_def (SYMBOL_LANGUAGE (func))->la_name_of_this;
2086 b = SYMBOL_BLOCK_VALUE (func);
2088 /* Calling lookup_block_symbol is necessary to get the LOC_REGISTER
2089 symbol instead of the LOC_ARG one (if both exist). */
2090 sym = lookup_block_symbol (b, this_name, VAR_DOMAIN);
2092 error (_("no `%s' found"), this_name);
2094 gen_var_ref (exp->gdbarch, ax, value, sym);
2096 if (value->optimized_out)
2097 error (_("`%s' has been optimized out, cannot use"),
2098 SYMBOL_PRINT_NAME (sym));
2106 struct type *type = (*pc)[1].type;
2107 int length = longest_to_int ((*pc)[2].longconst);
2108 char *name = &(*pc)[3].string;
2111 found = gen_aggregate_elt_ref (exp, ax, value, type, name,
2114 error (_("There is no field named %s"), name);
2115 (*pc) += 5 + BYTES_TO_EXP_ELEM (length + 1);
2120 error (_("Attempt to use a type name as an expression."));
2123 error (_("Unsupported operator %s (%d) in expression."),
2124 op_string (op), op);
2128 /* This handles the middle-to-right-side of code generation for binary
2129 expressions, which is shared between regular binary operations and
2130 assign-modify (+= and friends) expressions. */
2133 gen_expr_binop_rest (struct expression *exp,
2134 enum exp_opcode op, union exp_element **pc,
2135 struct agent_expr *ax, struct axs_value *value,
2136 struct axs_value *value1, struct axs_value *value2)
2138 gen_expr (exp, pc, ax, value2);
2139 gen_usual_unary (exp, ax, value2);
2140 gen_usual_arithmetic (exp, ax, value1, value2);
2144 if (TYPE_CODE (value1->type) == TYPE_CODE_INT
2145 && pointer_type (value2->type))
2147 /* Swap the values and proceed normally. */
2148 ax_simple (ax, aop_swap);
2149 gen_ptradd (ax, value, value2, value1);
2151 else if (pointer_type (value1->type)
2152 && TYPE_CODE (value2->type) == TYPE_CODE_INT)
2153 gen_ptradd (ax, value, value1, value2);
2155 gen_binop (ax, value, value1, value2,
2156 aop_add, aop_add, 1, "addition");
2159 if (pointer_type (value1->type)
2160 && TYPE_CODE (value2->type) == TYPE_CODE_INT)
2161 gen_ptrsub (ax,value, value1, value2);
2162 else if (pointer_type (value1->type)
2163 && pointer_type (value2->type))
2164 /* FIXME --- result type should be ptrdiff_t */
2165 gen_ptrdiff (ax, value, value1, value2,
2166 builtin_type (exp->gdbarch)->builtin_long);
2168 gen_binop (ax, value, value1, value2,
2169 aop_sub, aop_sub, 1, "subtraction");
2172 gen_binop (ax, value, value1, value2,
2173 aop_mul, aop_mul, 1, "multiplication");
2176 gen_binop (ax, value, value1, value2,
2177 aop_div_signed, aop_div_unsigned, 1, "division");
2180 gen_binop (ax, value, value1, value2,
2181 aop_rem_signed, aop_rem_unsigned, 1, "remainder");
2184 gen_binop (ax, value, value1, value2,
2185 aop_lsh, aop_lsh, 1, "left shift");
2188 gen_binop (ax, value, value1, value2,
2189 aop_rsh_signed, aop_rsh_unsigned, 1, "right shift");
2191 case BINOP_SUBSCRIPT:
2195 if (binop_types_user_defined_p (op, value1->type, value2->type))
2198 cannot subscript requested type: cannot call user defined functions"));
2202 /* If the user attempts to subscript something that is not
2203 an array or pointer type (like a plain int variable for
2204 example), then report this as an error. */
2205 type = check_typedef (value1->type);
2206 if (TYPE_CODE (type) != TYPE_CODE_ARRAY
2207 && TYPE_CODE (type) != TYPE_CODE_PTR)
2209 if (TYPE_NAME (type))
2210 error (_("cannot subscript something of type `%s'"),
2213 error (_("cannot subscript requested type"));
2217 if (!is_integral_type (value2->type))
2218 error (_("Argument to arithmetic operation not a number or boolean."));
2220 gen_ptradd (ax, value, value1, value2);
2221 gen_deref (ax, value);
2224 case BINOP_BITWISE_AND:
2225 gen_binop (ax, value, value1, value2,
2226 aop_bit_and, aop_bit_and, 0, "bitwise and");
2229 case BINOP_BITWISE_IOR:
2230 gen_binop (ax, value, value1, value2,
2231 aop_bit_or, aop_bit_or, 0, "bitwise or");
2234 case BINOP_BITWISE_XOR:
2235 gen_binop (ax, value, value1, value2,
2236 aop_bit_xor, aop_bit_xor, 0, "bitwise exclusive-or");
2240 gen_binop (ax, value, value1, value2,
2241 aop_equal, aop_equal, 0, "equal");
2244 case BINOP_NOTEQUAL:
2245 gen_binop (ax, value, value1, value2,
2246 aop_equal, aop_equal, 0, "equal");
2247 gen_logical_not (ax, value,
2248 language_bool_type (exp->language_defn,
2253 gen_binop (ax, value, value1, value2,
2254 aop_less_signed, aop_less_unsigned, 0, "less than");
2258 ax_simple (ax, aop_swap);
2259 gen_binop (ax, value, value1, value2,
2260 aop_less_signed, aop_less_unsigned, 0, "less than");
2264 ax_simple (ax, aop_swap);
2265 gen_binop (ax, value, value1, value2,
2266 aop_less_signed, aop_less_unsigned, 0, "less than");
2267 gen_logical_not (ax, value,
2268 language_bool_type (exp->language_defn,
2273 gen_binop (ax, value, value1, value2,
2274 aop_less_signed, aop_less_unsigned, 0, "less than");
2275 gen_logical_not (ax, value,
2276 language_bool_type (exp->language_defn,
2281 /* We should only list operators in the outer case statement
2282 that we actually handle in the inner case statement. */
2283 internal_error (__FILE__, __LINE__,
2284 _("gen_expr: op case sets don't match"));
2289 /* Given a single variable and a scope, generate bytecodes to trace
2290 its value. This is for use in situations where we have only a
2291 variable's name, and no parsed expression; for instance, when the
2292 name comes from a list of local variables of a function. */
2295 gen_trace_for_var (CORE_ADDR scope, struct gdbarch *gdbarch,
2298 struct cleanup *old_chain = 0;
2299 struct agent_expr *ax = new_agent_expr (scope);
2300 struct axs_value value;
2302 old_chain = make_cleanup_free_agent_expr (ax);
2305 gen_var_ref (gdbarch, ax, &value, var);
2307 /* If there is no actual variable to trace, flag it by returning
2308 an empty agent expression. */
2309 if (value.optimized_out)
2311 do_cleanups (old_chain);
2315 /* Make sure we record the final object, and get rid of it. */
2316 gen_traced_pop (gdbarch, ax, &value);
2318 /* Oh, and terminate. */
2319 ax_simple (ax, aop_end);
2321 /* We have successfully built the agent expr, so cancel the cleanup
2322 request. If we add more cleanups that we always want done, this
2323 will have to get more complicated. */
2324 discard_cleanups (old_chain);
2328 /* Generating bytecode from GDB expressions: driver */
2330 /* Given a GDB expression EXPR, return bytecode to trace its value.
2331 The result will use the `trace' and `trace_quick' bytecodes to
2332 record the value of all memory touched by the expression. The
2333 caller can then use the ax_reqs function to discover which
2334 registers it relies upon. */
2336 gen_trace_for_expr (CORE_ADDR scope, struct expression *expr)
2338 struct cleanup *old_chain = 0;
2339 struct agent_expr *ax = new_agent_expr (scope);
2340 union exp_element *pc;
2341 struct axs_value value;
2343 old_chain = make_cleanup_free_agent_expr (ax);
2347 gen_expr (expr, &pc, ax, &value);
2349 /* Make sure we record the final object, and get rid of it. */
2350 gen_traced_pop (expr->gdbarch, ax, &value);
2352 /* Oh, and terminate. */
2353 ax_simple (ax, aop_end);
2355 /* We have successfully built the agent expr, so cancel the cleanup
2356 request. If we add more cleanups that we always want done, this
2357 will have to get more complicated. */
2358 discard_cleanups (old_chain);
2362 /* Given a GDB expression EXPR, return a bytecode sequence that will
2363 evaluate and return a result. The bytecodes will do a direct
2364 evaluation, using the current data on the target, rather than
2365 recording blocks of memory and registers for later use, as
2366 gen_trace_for_expr does. The generated bytecode sequence leaves
2367 the result of expression evaluation on the top of the stack. */
2370 gen_eval_for_expr (CORE_ADDR scope, struct expression *expr)
2372 struct cleanup *old_chain = 0;
2373 struct agent_expr *ax = new_agent_expr (scope);
2374 union exp_element *pc;
2375 struct axs_value value;
2377 old_chain = make_cleanup_free_agent_expr (ax);
2381 gen_expr (expr, &pc, ax, &value);
2383 /* Oh, and terminate. */
2384 ax_simple (ax, aop_end);
2386 /* We have successfully built the agent expr, so cancel the cleanup
2387 request. If we add more cleanups that we always want done, this
2388 will have to get more complicated. */
2389 discard_cleanups (old_chain);
2394 agent_command (char *exp, int from_tty)
2396 struct cleanup *old_chain = 0;
2397 struct expression *expr;
2398 struct agent_expr *agent;
2399 struct frame_info *fi = get_current_frame (); /* need current scope */
2401 /* We don't deal with overlay debugging at the moment. We need to
2402 think more carefully about this. If you copy this code into
2403 another command, change the error message; the user shouldn't
2404 have to know anything about agent expressions. */
2405 if (overlay_debugging)
2406 error (_("GDB can't do agent expression translation with overlays."));
2409 error_no_arg (_("expression to translate"));
2411 expr = parse_expression (exp);
2412 old_chain = make_cleanup (free_current_contents, &expr);
2413 agent = gen_trace_for_expr (get_frame_pc (fi), expr);
2414 make_cleanup_free_agent_expr (agent);
2415 ax_print (gdb_stdout, agent);
2417 /* It would be nice to call ax_reqs here to gather some general info
2418 about the expression, and then print out the result. */
2420 do_cleanups (old_chain);
2424 /* Parse the given expression, compile it into an agent expression
2425 that does direct evaluation, and display the resulting
2429 agent_eval_command (char *exp, int from_tty)
2431 struct cleanup *old_chain = 0;
2432 struct expression *expr;
2433 struct agent_expr *agent;
2434 struct frame_info *fi = get_current_frame (); /* need current scope */
2436 /* We don't deal with overlay debugging at the moment. We need to
2437 think more carefully about this. If you copy this code into
2438 another command, change the error message; the user shouldn't
2439 have to know anything about agent expressions. */
2440 if (overlay_debugging)
2441 error (_("GDB can't do agent expression translation with overlays."));
2444 error_no_arg (_("expression to translate"));
2446 expr = parse_expression (exp);
2447 old_chain = make_cleanup (free_current_contents, &expr);
2448 agent = gen_eval_for_expr (get_frame_pc (fi), expr);
2449 make_cleanup_free_agent_expr (agent);
2450 ax_print (gdb_stdout, agent);
2452 /* It would be nice to call ax_reqs here to gather some general info
2453 about the expression, and then print out the result. */
2455 do_cleanups (old_chain);
2460 /* Initialization code. */
2462 void _initialize_ax_gdb (void);
2464 _initialize_ax_gdb (void)
2466 add_cmd ("agent", class_maintenance, agent_command,
2467 _("Translate an expression into remote agent bytecode for tracing."),
2470 add_cmd ("agent-eval", class_maintenance, agent_eval_command,
2471 _("Translate an expression into remote agent bytecode for evaluation."),