1 /* GDB-specific functions for operating on agent expressions.
3 Copyright (C) 1998-2001, 2003, 2007-2012 Free Software Foundation,
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"
43 #include "arch-utils.h"
48 /* To make sense of this file, you should read doc/agentexpr.texi.
49 Then look at the types and enums in ax-gdb.h. For the code itself,
50 look at gen_expr, towards the bottom; that's the main function that
51 looks at the GDB expressions and calls everything else to generate
54 I'm beginning to wonder whether it wouldn't be nicer to internally
55 generate trees, with types, and then spit out the bytecode in
56 linear form afterwards; we could generate fewer `swap', `ext', and
57 `zero_ext' bytecodes that way; it would make good constant folding
58 easier, too. But at the moment, I think we should be willing to
59 pay for the simplicity of this code with less-than-optimal bytecode
62 Remember, "GBD" stands for "Great Britain, Dammit!" So be careful. */
66 /* Prototypes for local functions. */
68 /* There's a standard order to the arguments of these functions:
69 union exp_element ** --- pointer into expression
70 struct agent_expr * --- agent expression buffer to generate code into
71 struct axs_value * --- describes value left on top of stack */
73 static struct value
*const_var_ref (struct symbol
*var
);
74 static struct value
*const_expr (union exp_element
**pc
);
75 static struct value
*maybe_const_expr (union exp_element
**pc
);
77 static void gen_traced_pop (struct gdbarch
*, struct agent_expr
*,
80 static void gen_sign_extend (struct agent_expr
*, struct type
*);
81 static void gen_extend (struct agent_expr
*, struct type
*);
82 static void gen_fetch (struct agent_expr
*, struct type
*);
83 static void gen_left_shift (struct agent_expr
*, int);
86 static void gen_frame_args_address (struct gdbarch
*, struct agent_expr
*);
87 static void gen_frame_locals_address (struct gdbarch
*, struct agent_expr
*);
88 static void gen_offset (struct agent_expr
*ax
, int offset
);
89 static void gen_sym_offset (struct agent_expr
*, struct symbol
*);
90 static void gen_var_ref (struct gdbarch
*, struct agent_expr
*ax
,
91 struct axs_value
*value
, struct symbol
*var
);
94 static void gen_int_literal (struct agent_expr
*ax
,
95 struct axs_value
*value
,
96 LONGEST k
, struct type
*type
);
99 static void require_rvalue (struct agent_expr
*ax
, struct axs_value
*value
);
100 static void gen_usual_unary (struct expression
*exp
, struct agent_expr
*ax
,
101 struct axs_value
*value
);
102 static int type_wider_than (struct type
*type1
, struct type
*type2
);
103 static struct type
*max_type (struct type
*type1
, struct type
*type2
);
104 static void gen_conversion (struct agent_expr
*ax
,
105 struct type
*from
, struct type
*to
);
106 static int is_nontrivial_conversion (struct type
*from
, struct type
*to
);
107 static void gen_usual_arithmetic (struct expression
*exp
,
108 struct agent_expr
*ax
,
109 struct axs_value
*value1
,
110 struct axs_value
*value2
);
111 static void gen_integral_promotions (struct expression
*exp
,
112 struct agent_expr
*ax
,
113 struct axs_value
*value
);
114 static void gen_cast (struct agent_expr
*ax
,
115 struct axs_value
*value
, struct type
*type
);
116 static void gen_scale (struct agent_expr
*ax
,
117 enum agent_op op
, struct type
*type
);
118 static void gen_ptradd (struct agent_expr
*ax
, struct axs_value
*value
,
119 struct axs_value
*value1
, struct axs_value
*value2
);
120 static void gen_ptrsub (struct agent_expr
*ax
, struct axs_value
*value
,
121 struct axs_value
*value1
, struct axs_value
*value2
);
122 static void gen_ptrdiff (struct agent_expr
*ax
, struct axs_value
*value
,
123 struct axs_value
*value1
, struct axs_value
*value2
,
124 struct type
*result_type
);
125 static void gen_binop (struct agent_expr
*ax
,
126 struct axs_value
*value
,
127 struct axs_value
*value1
,
128 struct axs_value
*value2
,
130 enum agent_op op_unsigned
, int may_carry
, char *name
);
131 static void gen_logical_not (struct agent_expr
*ax
, struct axs_value
*value
,
132 struct type
*result_type
);
133 static void gen_complement (struct agent_expr
*ax
, struct axs_value
*value
);
134 static void gen_deref (struct agent_expr
*, struct axs_value
*);
135 static void gen_address_of (struct agent_expr
*, struct axs_value
*);
136 static void gen_bitfield_ref (struct expression
*exp
, struct agent_expr
*ax
,
137 struct axs_value
*value
,
138 struct type
*type
, int start
, int end
);
139 static void gen_primitive_field (struct expression
*exp
,
140 struct agent_expr
*ax
,
141 struct axs_value
*value
,
142 int offset
, int fieldno
, struct type
*type
);
143 static int gen_struct_ref_recursive (struct expression
*exp
,
144 struct agent_expr
*ax
,
145 struct axs_value
*value
,
146 char *field
, int offset
,
148 static void gen_struct_ref (struct expression
*exp
, struct agent_expr
*ax
,
149 struct axs_value
*value
,
151 char *operator_name
, char *operand_name
);
152 static void gen_static_field (struct gdbarch
*gdbarch
,
153 struct agent_expr
*ax
, struct axs_value
*value
,
154 struct type
*type
, int fieldno
);
155 static void gen_repeat (struct expression
*exp
, union exp_element
**pc
,
156 struct agent_expr
*ax
, struct axs_value
*value
);
157 static void gen_sizeof (struct expression
*exp
, union exp_element
**pc
,
158 struct agent_expr
*ax
, struct axs_value
*value
,
159 struct type
*size_type
);
160 static void gen_expr (struct expression
*exp
, union exp_element
**pc
,
161 struct agent_expr
*ax
, struct axs_value
*value
);
162 static void gen_expr_binop_rest (struct expression
*exp
,
163 enum exp_opcode op
, union exp_element
**pc
,
164 struct agent_expr
*ax
,
165 struct axs_value
*value
,
166 struct axs_value
*value1
,
167 struct axs_value
*value2
);
169 static void agent_command (char *exp
, int from_tty
);
172 /* Detecting constant expressions. */
174 /* If the variable reference at *PC is a constant, return its value.
175 Otherwise, return zero.
177 Hey, Wally! How can a variable reference be a constant?
179 Well, Beav, this function really handles the OP_VAR_VALUE operator,
180 not specifically variable references. GDB uses OP_VAR_VALUE to
181 refer to any kind of symbolic reference: function names, enum
182 elements, and goto labels are all handled through the OP_VAR_VALUE
183 operator, even though they're constants. It makes sense given the
186 Gee, Wally, don'cha wonder sometimes if data representations that
187 subvert commonly accepted definitions of terms in favor of heavily
188 context-specific interpretations are really just a tool of the
189 programming hegemony to preserve their power and exclude the
192 static struct value
*
193 const_var_ref (struct symbol
*var
)
195 struct type
*type
= SYMBOL_TYPE (var
);
197 switch (SYMBOL_CLASS (var
))
200 return value_from_longest (type
, (LONGEST
) SYMBOL_VALUE (var
));
203 return value_from_pointer (type
, (CORE_ADDR
) SYMBOL_VALUE_ADDRESS (var
));
211 /* If the expression starting at *PC has a constant value, return it.
212 Otherwise, return zero. If we return a value, then *PC will be
213 advanced to the end of it. If we return zero, *PC could be
215 static struct value
*
216 const_expr (union exp_element
**pc
)
218 enum exp_opcode op
= (*pc
)->opcode
;
225 struct type
*type
= (*pc
)[1].type
;
226 LONGEST k
= (*pc
)[2].longconst
;
229 return value_from_longest (type
, k
);
234 struct value
*v
= const_var_ref ((*pc
)[2].symbol
);
240 /* We could add more operators in here. */
244 v1
= const_expr (pc
);
246 return value_neg (v1
);
256 /* Like const_expr, but guarantee also that *PC is undisturbed if the
257 expression is not constant. */
258 static struct value
*
259 maybe_const_expr (union exp_element
**pc
)
261 union exp_element
*tentative_pc
= *pc
;
262 struct value
*v
= const_expr (&tentative_pc
);
264 /* If we got a value, then update the real PC. */
272 /* Generating bytecode from GDB expressions: general assumptions */
274 /* Here are a few general assumptions made throughout the code; if you
275 want to make a change that contradicts one of these, then you'd
276 better scan things pretty thoroughly.
278 - We assume that all values occupy one stack element. For example,
279 sometimes we'll swap to get at the left argument to a binary
280 operator. If we decide that void values should occupy no stack
281 elements, or that synthetic arrays (whose size is determined at
282 run time, created by the `@' operator) should occupy two stack
283 elements (address and length), then this will cause trouble.
285 - We assume the stack elements are infinitely wide, and that we
286 don't have to worry what happens if the user requests an
287 operation that is wider than the actual interpreter's stack.
288 That is, it's up to the interpreter to handle directly all the
289 integer widths the user has access to. (Woe betide the language
292 - We don't support side effects. Thus, we don't have to worry about
293 GCC's generalized lvalues, function calls, etc.
295 - We don't support floating point. Many places where we switch on
296 some type don't bother to include cases for floating point; there
297 may be even more subtle ways this assumption exists. For
298 example, the arguments to % must be integers.
300 - We assume all subexpressions have a static, unchanging type. If
301 we tried to support convenience variables, this would be a
304 - All values on the stack should always be fully zero- or
307 (I wasn't sure whether to choose this or its opposite --- that
308 only addresses are assumed extended --- but it turns out that
309 neither convention completely eliminates spurious extend
310 operations (if everything is always extended, then you have to
311 extend after add, because it could overflow; if nothing is
312 extended, then you end up producing extends whenever you change
313 sizes), and this is simpler.) */
316 /* Generating bytecode from GDB expressions: the `trace' kludge */
318 /* The compiler in this file is a general-purpose mechanism for
319 translating GDB expressions into bytecode. One ought to be able to
320 find a million and one uses for it.
322 However, at the moment it is HOPELESSLY BRAIN-DAMAGED for the sake
323 of expediency. Let he who is without sin cast the first stone.
325 For the data tracing facility, we need to insert `trace' bytecodes
326 before each data fetch; this records all the memory that the
327 expression touches in the course of evaluation, so that memory will
328 be available when the user later tries to evaluate the expression
331 This should be done (I think) in a post-processing pass, that walks
332 an arbitrary agent expression and inserts `trace' operations at the
333 appropriate points. But it's much faster to just hack them
334 directly into the code. And since we're in a crunch, that's what
337 Setting the flag trace_kludge to non-zero enables the code that
338 emits the trace bytecodes at the appropriate points. */
341 /* Inspired by trace_kludge, this indicates that pointers to chars
342 should get an added tracenz bytecode to record nonzero bytes, up to
343 a length that is the value of trace_string_kludge. */
344 int trace_string_kludge
;
346 /* Scan for all static fields in the given class, including any base
347 classes, and generate tracing bytecodes for each. */
350 gen_trace_static_fields (struct gdbarch
*gdbarch
,
351 struct agent_expr
*ax
,
354 int i
, nbases
= TYPE_N_BASECLASSES (type
);
355 struct axs_value value
;
357 CHECK_TYPEDEF (type
);
359 for (i
= TYPE_NFIELDS (type
) - 1; i
>= nbases
; i
--)
361 if (field_is_static (&TYPE_FIELD (type
, i
)))
363 gen_static_field (gdbarch
, ax
, &value
, type
, i
);
364 if (value
.optimized_out
)
368 case axs_lvalue_memory
:
370 int length
= TYPE_LENGTH (check_typedef (value
.type
));
372 ax_const_l (ax
, length
);
373 ax_simple (ax
, aop_trace
);
377 case axs_lvalue_register
:
378 /* We don't actually need the register's value to be pushed,
379 just note that we need it to be collected. */
380 ax_reg_mask (ax
, value
.u
.reg
);
388 /* Now scan through base classes recursively. */
389 for (i
= 0; i
< nbases
; i
++)
391 struct type
*basetype
= check_typedef (TYPE_BASECLASS (type
, i
));
393 gen_trace_static_fields (gdbarch
, ax
, basetype
);
397 /* Trace the lvalue on the stack, if it needs it. In either case, pop
398 the value. Useful on the left side of a comma, and at the end of
399 an expression being used for tracing. */
401 gen_traced_pop (struct gdbarch
*gdbarch
,
402 struct agent_expr
*ax
, struct axs_value
*value
)
404 int string_trace
= 0;
405 if (trace_string_kludge
406 && TYPE_CODE (value
->type
) == TYPE_CODE_PTR
407 && c_textual_element_type (check_typedef (TYPE_TARGET_TYPE (value
->type
)),
417 ax_const_l (ax
, trace_string_kludge
);
418 ax_simple (ax
, aop_tracenz
);
421 /* We don't trace rvalues, just the lvalues necessary to
422 produce them. So just dispose of this value. */
423 ax_simple (ax
, aop_pop
);
426 case axs_lvalue_memory
:
428 int length
= TYPE_LENGTH (check_typedef (value
->type
));
431 ax_simple (ax
, aop_dup
);
433 /* There's no point in trying to use a trace_quick bytecode
434 here, since "trace_quick SIZE pop" is three bytes, whereas
435 "const8 SIZE trace" is also three bytes, does the same
436 thing, and the simplest code which generates that will also
437 work correctly for objects with large sizes. */
438 ax_const_l (ax
, length
);
439 ax_simple (ax
, aop_trace
);
443 ax_simple (ax
, aop_ref32
);
444 ax_const_l (ax
, trace_string_kludge
);
445 ax_simple (ax
, aop_tracenz
);
450 case axs_lvalue_register
:
451 /* We don't actually need the register's value to be on the
452 stack, and the target will get heartburn if the register is
453 larger than will fit in a stack, so just mark it for
454 collection and be done with it. */
455 ax_reg_mask (ax
, value
->u
.reg
);
457 /* But if the register points to a string, assume the value
458 will fit on the stack and push it anyway. */
461 ax_reg (ax
, value
->u
.reg
);
462 ax_const_l (ax
, trace_string_kludge
);
463 ax_simple (ax
, aop_tracenz
);
468 /* If we're not tracing, just pop the value. */
469 ax_simple (ax
, aop_pop
);
471 /* To trace C++ classes with static fields stored elsewhere. */
473 && (TYPE_CODE (value
->type
) == TYPE_CODE_STRUCT
474 || TYPE_CODE (value
->type
) == TYPE_CODE_UNION
))
475 gen_trace_static_fields (gdbarch
, ax
, value
->type
);
480 /* Generating bytecode from GDB expressions: helper functions */
482 /* Assume that the lower bits of the top of the stack is a value of
483 type TYPE, and the upper bits are zero. Sign-extend if necessary. */
485 gen_sign_extend (struct agent_expr
*ax
, struct type
*type
)
487 /* Do we need to sign-extend this? */
488 if (!TYPE_UNSIGNED (type
))
489 ax_ext (ax
, TYPE_LENGTH (type
) * TARGET_CHAR_BIT
);
493 /* Assume the lower bits of the top of the stack hold a value of type
494 TYPE, and the upper bits are garbage. Sign-extend or truncate as
497 gen_extend (struct agent_expr
*ax
, struct type
*type
)
499 int bits
= TYPE_LENGTH (type
) * TARGET_CHAR_BIT
;
502 ((TYPE_UNSIGNED (type
) ? ax_zero_ext
: ax_ext
) (ax
, bits
));
506 /* Assume that the top of the stack contains a value of type "pointer
507 to TYPE"; generate code to fetch its value. Note that TYPE is the
508 target type, not the pointer type. */
510 gen_fetch (struct agent_expr
*ax
, struct type
*type
)
514 /* Record the area of memory we're about to fetch. */
515 ax_trace_quick (ax
, TYPE_LENGTH (type
));
518 switch (TYPE_CODE (type
))
526 /* It's a scalar value, so we know how to dereference it. How
527 many bytes long is it? */
528 switch (TYPE_LENGTH (type
))
530 case 8 / TARGET_CHAR_BIT
:
531 ax_simple (ax
, aop_ref8
);
533 case 16 / TARGET_CHAR_BIT
:
534 ax_simple (ax
, aop_ref16
);
536 case 32 / TARGET_CHAR_BIT
:
537 ax_simple (ax
, aop_ref32
);
539 case 64 / TARGET_CHAR_BIT
:
540 ax_simple (ax
, aop_ref64
);
543 /* Either our caller shouldn't have asked us to dereference
544 that pointer (other code's fault), or we're not
545 implementing something we should be (this code's fault).
546 In any case, it's a bug the user shouldn't see. */
548 internal_error (__FILE__
, __LINE__
,
549 _("gen_fetch: strange size"));
552 gen_sign_extend (ax
, type
);
556 /* Either our caller shouldn't have asked us to dereference that
557 pointer (other code's fault), or we're not implementing
558 something we should be (this code's fault). In any case,
559 it's a bug the user shouldn't see. */
560 internal_error (__FILE__
, __LINE__
,
561 _("gen_fetch: bad type code"));
566 /* Generate code to left shift the top of the stack by DISTANCE bits, or
567 right shift it by -DISTANCE bits if DISTANCE < 0. This generates
568 unsigned (logical) right shifts. */
570 gen_left_shift (struct agent_expr
*ax
, int distance
)
574 ax_const_l (ax
, distance
);
575 ax_simple (ax
, aop_lsh
);
577 else if (distance
< 0)
579 ax_const_l (ax
, -distance
);
580 ax_simple (ax
, aop_rsh_unsigned
);
586 /* Generating bytecode from GDB expressions: symbol references */
588 /* Generate code to push the base address of the argument portion of
589 the top stack frame. */
591 gen_frame_args_address (struct gdbarch
*gdbarch
, struct agent_expr
*ax
)
594 LONGEST frame_offset
;
596 gdbarch_virtual_frame_pointer (gdbarch
,
597 ax
->scope
, &frame_reg
, &frame_offset
);
598 ax_reg (ax
, frame_reg
);
599 gen_offset (ax
, frame_offset
);
603 /* Generate code to push the base address of the locals portion of the
606 gen_frame_locals_address (struct gdbarch
*gdbarch
, struct agent_expr
*ax
)
609 LONGEST frame_offset
;
611 gdbarch_virtual_frame_pointer (gdbarch
,
612 ax
->scope
, &frame_reg
, &frame_offset
);
613 ax_reg (ax
, frame_reg
);
614 gen_offset (ax
, frame_offset
);
618 /* Generate code to add OFFSET to the top of the stack. Try to
619 generate short and readable code. We use this for getting to
620 variables on the stack, and structure members. If we were
621 programming in ML, it would be clearer why these are the same
624 gen_offset (struct agent_expr
*ax
, int offset
)
626 /* It would suffice to simply push the offset and add it, but this
627 makes it easier to read positive and negative offsets in the
631 ax_const_l (ax
, offset
);
632 ax_simple (ax
, aop_add
);
636 ax_const_l (ax
, -offset
);
637 ax_simple (ax
, aop_sub
);
642 /* In many cases, a symbol's value is the offset from some other
643 address (stack frame, base register, etc.) Generate code to add
644 VAR's value to the top of the stack. */
646 gen_sym_offset (struct agent_expr
*ax
, struct symbol
*var
)
648 gen_offset (ax
, SYMBOL_VALUE (var
));
652 /* Generate code for a variable reference to AX. The variable is the
653 symbol VAR. Set VALUE to describe the result. */
656 gen_var_ref (struct gdbarch
*gdbarch
, struct agent_expr
*ax
,
657 struct axs_value
*value
, struct symbol
*var
)
659 /* Dereference any typedefs. */
660 value
->type
= check_typedef (SYMBOL_TYPE (var
));
661 value
->optimized_out
= 0;
663 /* I'm imitating the code in read_var_value. */
664 switch (SYMBOL_CLASS (var
))
666 case LOC_CONST
: /* A constant, like an enum value. */
667 ax_const_l (ax
, (LONGEST
) SYMBOL_VALUE (var
));
668 value
->kind
= axs_rvalue
;
671 case LOC_LABEL
: /* A goto label, being used as a value. */
672 ax_const_l (ax
, (LONGEST
) SYMBOL_VALUE_ADDRESS (var
));
673 value
->kind
= axs_rvalue
;
676 case LOC_CONST_BYTES
:
677 internal_error (__FILE__
, __LINE__
,
678 _("gen_var_ref: LOC_CONST_BYTES "
679 "symbols are not supported"));
681 /* Variable at a fixed location in memory. Easy. */
683 /* Push the address of the variable. */
684 ax_const_l (ax
, SYMBOL_VALUE_ADDRESS (var
));
685 value
->kind
= axs_lvalue_memory
;
688 case LOC_ARG
: /* var lives in argument area of frame */
689 gen_frame_args_address (gdbarch
, ax
);
690 gen_sym_offset (ax
, var
);
691 value
->kind
= axs_lvalue_memory
;
694 case LOC_REF_ARG
: /* As above, but the frame slot really
695 holds the address of the variable. */
696 gen_frame_args_address (gdbarch
, ax
);
697 gen_sym_offset (ax
, var
);
698 /* Don't assume any particular pointer size. */
699 gen_fetch (ax
, builtin_type (gdbarch
)->builtin_data_ptr
);
700 value
->kind
= axs_lvalue_memory
;
703 case LOC_LOCAL
: /* var lives in locals area of frame */
704 gen_frame_locals_address (gdbarch
, ax
);
705 gen_sym_offset (ax
, var
);
706 value
->kind
= axs_lvalue_memory
;
710 error (_("Cannot compute value of typedef `%s'."),
711 SYMBOL_PRINT_NAME (var
));
715 ax_const_l (ax
, BLOCK_START (SYMBOL_BLOCK_VALUE (var
)));
716 value
->kind
= axs_rvalue
;
720 /* Don't generate any code at all; in the process of treating
721 this as an lvalue or rvalue, the caller will generate the
723 value
->kind
= axs_lvalue_register
;
724 value
->u
.reg
= SYMBOL_REGISTER_OPS (var
)->register_number (var
, gdbarch
);
727 /* A lot like LOC_REF_ARG, but the pointer lives directly in a
728 register, not on the stack. Simpler than LOC_REGISTER
729 because it's just like any other case where the thing
730 has a real address. */
731 case LOC_REGPARM_ADDR
:
732 ax_reg (ax
, SYMBOL_REGISTER_OPS (var
)->register_number (var
, gdbarch
));
733 value
->kind
= axs_lvalue_memory
;
738 struct minimal_symbol
*msym
739 = lookup_minimal_symbol (SYMBOL_LINKAGE_NAME (var
), NULL
, NULL
);
742 error (_("Couldn't resolve symbol `%s'."), SYMBOL_PRINT_NAME (var
));
744 /* Push the address of the variable. */
745 ax_const_l (ax
, SYMBOL_VALUE_ADDRESS (msym
));
746 value
->kind
= axs_lvalue_memory
;
751 /* FIXME: cagney/2004-01-26: It should be possible to
752 unconditionally call the SYMBOL_COMPUTED_OPS method when available.
753 Unfortunately DWARF 2 stores the frame-base (instead of the
754 function) location in a function's symbol. Oops! For the
755 moment enable this when/where applicable. */
756 SYMBOL_COMPUTED_OPS (var
)->tracepoint_var_ref (var
, gdbarch
, ax
, value
);
759 case LOC_OPTIMIZED_OUT
:
760 /* Flag this, but don't say anything; leave it up to callers to
762 value
->optimized_out
= 1;
766 error (_("Cannot find value of botched symbol `%s'."),
767 SYMBOL_PRINT_NAME (var
));
774 /* Generating bytecode from GDB expressions: literals */
777 gen_int_literal (struct agent_expr
*ax
, struct axs_value
*value
, LONGEST k
,
781 value
->kind
= axs_rvalue
;
782 value
->type
= check_typedef (type
);
787 /* Generating bytecode from GDB expressions: unary conversions, casts */
789 /* Take what's on the top of the stack (as described by VALUE), and
790 try to make an rvalue out of it. Signal an error if we can't do
793 require_rvalue (struct agent_expr
*ax
, struct axs_value
*value
)
795 /* Only deal with scalars, structs and such may be too large
796 to fit in a stack entry. */
797 value
->type
= check_typedef (value
->type
);
798 if (TYPE_CODE (value
->type
) == TYPE_CODE_ARRAY
799 || TYPE_CODE (value
->type
) == TYPE_CODE_STRUCT
800 || TYPE_CODE (value
->type
) == TYPE_CODE_UNION
801 || TYPE_CODE (value
->type
) == TYPE_CODE_FUNC
)
802 error (_("Value not scalar: cannot be an rvalue."));
807 /* It's already an rvalue. */
810 case axs_lvalue_memory
:
811 /* The top of stack is the address of the object. Dereference. */
812 gen_fetch (ax
, value
->type
);
815 case axs_lvalue_register
:
816 /* There's nothing on the stack, but value->u.reg is the
817 register number containing the value.
819 When we add floating-point support, this is going to have to
820 change. What about SPARC register pairs, for example? */
821 ax_reg (ax
, value
->u
.reg
);
822 gen_extend (ax
, value
->type
);
826 value
->kind
= axs_rvalue
;
830 /* Assume the top of the stack is described by VALUE, and perform the
831 usual unary conversions. This is motivated by ANSI 6.2.2, but of
832 course GDB expressions are not ANSI; they're the mishmash union of
833 a bunch of languages. Rah.
835 NOTE! This function promises to produce an rvalue only when the
836 incoming value is of an appropriate type. In other words, the
837 consumer of the value this function produces may assume the value
838 is an rvalue only after checking its type.
840 The immediate issue is that if the user tries to use a structure or
841 union as an operand of, say, the `+' operator, we don't want to try
842 to convert that structure to an rvalue; require_rvalue will bomb on
843 structs and unions. Rather, we want to simply pass the struct
844 lvalue through unchanged, and let `+' raise an error. */
847 gen_usual_unary (struct expression
*exp
, struct agent_expr
*ax
,
848 struct axs_value
*value
)
850 /* We don't have to generate any code for the usual integral
851 conversions, since values are always represented as full-width on
852 the stack. Should we tweak the type? */
854 /* Some types require special handling. */
855 switch (TYPE_CODE (value
->type
))
857 /* Functions get converted to a pointer to the function. */
859 value
->type
= lookup_pointer_type (value
->type
);
860 value
->kind
= axs_rvalue
; /* Should always be true, but just in case. */
863 /* Arrays get converted to a pointer to their first element, and
864 are no longer an lvalue. */
865 case TYPE_CODE_ARRAY
:
867 struct type
*elements
= TYPE_TARGET_TYPE (value
->type
);
869 value
->type
= lookup_pointer_type (elements
);
870 value
->kind
= axs_rvalue
;
871 /* We don't need to generate any code; the address of the array
872 is also the address of its first element. */
876 /* Don't try to convert structures and unions to rvalues. Let the
877 consumer signal an error. */
878 case TYPE_CODE_STRUCT
:
879 case TYPE_CODE_UNION
:
882 /* If the value is an enum or a bool, call it an integer. */
885 value
->type
= builtin_type (exp
->gdbarch
)->builtin_int
;
889 /* If the value is an lvalue, dereference it. */
890 require_rvalue (ax
, value
);
894 /* Return non-zero iff the type TYPE1 is considered "wider" than the
895 type TYPE2, according to the rules described in gen_usual_arithmetic. */
897 type_wider_than (struct type
*type1
, struct type
*type2
)
899 return (TYPE_LENGTH (type1
) > TYPE_LENGTH (type2
)
900 || (TYPE_LENGTH (type1
) == TYPE_LENGTH (type2
)
901 && TYPE_UNSIGNED (type1
)
902 && !TYPE_UNSIGNED (type2
)));
906 /* Return the "wider" of the two types TYPE1 and TYPE2. */
908 max_type (struct type
*type1
, struct type
*type2
)
910 return type_wider_than (type1
, type2
) ? type1
: type2
;
914 /* Generate code to convert a scalar value of type FROM to type TO. */
916 gen_conversion (struct agent_expr
*ax
, struct type
*from
, struct type
*to
)
918 /* Perhaps there is a more graceful way to state these rules. */
920 /* If we're converting to a narrower type, then we need to clear out
922 if (TYPE_LENGTH (to
) < TYPE_LENGTH (from
))
923 gen_extend (ax
, from
);
925 /* If the two values have equal width, but different signednesses,
926 then we need to extend. */
927 else if (TYPE_LENGTH (to
) == TYPE_LENGTH (from
))
929 if (TYPE_UNSIGNED (from
) != TYPE_UNSIGNED (to
))
933 /* If we're converting to a wider type, and becoming unsigned, then
934 we need to zero out any possible sign bits. */
935 else if (TYPE_LENGTH (to
) > TYPE_LENGTH (from
))
937 if (TYPE_UNSIGNED (to
))
943 /* Return non-zero iff the type FROM will require any bytecodes to be
944 emitted to be converted to the type TO. */
946 is_nontrivial_conversion (struct type
*from
, struct type
*to
)
948 struct agent_expr
*ax
= new_agent_expr (NULL
, 0);
951 /* Actually generate the code, and see if anything came out. At the
952 moment, it would be trivial to replicate the code in
953 gen_conversion here, but in the future, when we're supporting
954 floating point and the like, it may not be. Doing things this
955 way allows this function to be independent of the logic in
957 gen_conversion (ax
, from
, to
);
958 nontrivial
= ax
->len
> 0;
959 free_agent_expr (ax
);
964 /* Generate code to perform the "usual arithmetic conversions" (ANSI C
965 6.2.1.5) for the two operands of an arithmetic operator. This
966 effectively finds a "least upper bound" type for the two arguments,
967 and promotes each argument to that type. *VALUE1 and *VALUE2
968 describe the values as they are passed in, and as they are left. */
970 gen_usual_arithmetic (struct expression
*exp
, struct agent_expr
*ax
,
971 struct axs_value
*value1
, struct axs_value
*value2
)
973 /* Do the usual binary conversions. */
974 if (TYPE_CODE (value1
->type
) == TYPE_CODE_INT
975 && TYPE_CODE (value2
->type
) == TYPE_CODE_INT
)
977 /* The ANSI integral promotions seem to work this way: Order the
978 integer types by size, and then by signedness: an n-bit
979 unsigned type is considered "wider" than an n-bit signed
980 type. Promote to the "wider" of the two types, and always
981 promote at least to int. */
982 struct type
*target
= max_type (builtin_type (exp
->gdbarch
)->builtin_int
,
983 max_type (value1
->type
, value2
->type
));
985 /* Deal with value2, on the top of the stack. */
986 gen_conversion (ax
, value2
->type
, target
);
988 /* Deal with value1, not on the top of the stack. Don't
989 generate the `swap' instructions if we're not actually going
991 if (is_nontrivial_conversion (value1
->type
, target
))
993 ax_simple (ax
, aop_swap
);
994 gen_conversion (ax
, value1
->type
, target
);
995 ax_simple (ax
, aop_swap
);
998 value1
->type
= value2
->type
= check_typedef (target
);
1003 /* Generate code to perform the integral promotions (ANSI 6.2.1.1) on
1004 the value on the top of the stack, as described by VALUE. Assume
1005 the value has integral type. */
1007 gen_integral_promotions (struct expression
*exp
, struct agent_expr
*ax
,
1008 struct axs_value
*value
)
1010 const struct builtin_type
*builtin
= builtin_type (exp
->gdbarch
);
1012 if (!type_wider_than (value
->type
, builtin
->builtin_int
))
1014 gen_conversion (ax
, value
->type
, builtin
->builtin_int
);
1015 value
->type
= builtin
->builtin_int
;
1017 else if (!type_wider_than (value
->type
, builtin
->builtin_unsigned_int
))
1019 gen_conversion (ax
, value
->type
, builtin
->builtin_unsigned_int
);
1020 value
->type
= builtin
->builtin_unsigned_int
;
1025 /* Generate code for a cast to TYPE. */
1027 gen_cast (struct agent_expr
*ax
, struct axs_value
*value
, struct type
*type
)
1029 /* GCC does allow casts to yield lvalues, so this should be fixed
1030 before merging these changes into the trunk. */
1031 require_rvalue (ax
, value
);
1032 /* Dereference typedefs. */
1033 type
= check_typedef (type
);
1035 switch (TYPE_CODE (type
))
1039 /* It's implementation-defined, and I'll bet this is what GCC
1043 case TYPE_CODE_ARRAY
:
1044 case TYPE_CODE_STRUCT
:
1045 case TYPE_CODE_UNION
:
1046 case TYPE_CODE_FUNC
:
1047 error (_("Invalid type cast: intended type must be scalar."));
1049 case TYPE_CODE_ENUM
:
1050 case TYPE_CODE_BOOL
:
1051 /* We don't have to worry about the size of the value, because
1052 all our integral values are fully sign-extended, and when
1053 casting pointers we can do anything we like. Is there any
1054 way for us to know what GCC actually does with a cast like
1059 gen_conversion (ax
, value
->type
, type
);
1062 case TYPE_CODE_VOID
:
1063 /* We could pop the value, and rely on everyone else to check
1064 the type and notice that this value doesn't occupy a stack
1065 slot. But for now, leave the value on the stack, and
1066 preserve the "value == stack element" assumption. */
1070 error (_("Casts to requested type are not yet implemented."));
1078 /* Generating bytecode from GDB expressions: arithmetic */
1080 /* Scale the integer on the top of the stack by the size of the target
1081 of the pointer type TYPE. */
1083 gen_scale (struct agent_expr
*ax
, enum agent_op op
, struct type
*type
)
1085 struct type
*element
= TYPE_TARGET_TYPE (type
);
1087 if (TYPE_LENGTH (element
) != 1)
1089 ax_const_l (ax
, TYPE_LENGTH (element
));
1095 /* Generate code for pointer arithmetic PTR + INT. */
1097 gen_ptradd (struct agent_expr
*ax
, struct axs_value
*value
,
1098 struct axs_value
*value1
, struct axs_value
*value2
)
1100 gdb_assert (pointer_type (value1
->type
));
1101 gdb_assert (TYPE_CODE (value2
->type
) == TYPE_CODE_INT
);
1103 gen_scale (ax
, aop_mul
, value1
->type
);
1104 ax_simple (ax
, aop_add
);
1105 gen_extend (ax
, value1
->type
); /* Catch overflow. */
1106 value
->type
= value1
->type
;
1107 value
->kind
= axs_rvalue
;
1111 /* Generate code for pointer arithmetic PTR - INT. */
1113 gen_ptrsub (struct agent_expr
*ax
, struct axs_value
*value
,
1114 struct axs_value
*value1
, struct axs_value
*value2
)
1116 gdb_assert (pointer_type (value1
->type
));
1117 gdb_assert (TYPE_CODE (value2
->type
) == TYPE_CODE_INT
);
1119 gen_scale (ax
, aop_mul
, value1
->type
);
1120 ax_simple (ax
, aop_sub
);
1121 gen_extend (ax
, value1
->type
); /* Catch overflow. */
1122 value
->type
= value1
->type
;
1123 value
->kind
= axs_rvalue
;
1127 /* Generate code for pointer arithmetic PTR - PTR. */
1129 gen_ptrdiff (struct agent_expr
*ax
, struct axs_value
*value
,
1130 struct axs_value
*value1
, struct axs_value
*value2
,
1131 struct type
*result_type
)
1133 gdb_assert (pointer_type (value1
->type
));
1134 gdb_assert (pointer_type (value2
->type
));
1136 if (TYPE_LENGTH (TYPE_TARGET_TYPE (value1
->type
))
1137 != TYPE_LENGTH (TYPE_TARGET_TYPE (value2
->type
)))
1139 First argument of `-' is a pointer, but second argument is neither\n\
1140 an integer nor a pointer of the same type."));
1142 ax_simple (ax
, aop_sub
);
1143 gen_scale (ax
, aop_div_unsigned
, value1
->type
);
1144 value
->type
= result_type
;
1145 value
->kind
= axs_rvalue
;
1149 gen_equal (struct agent_expr
*ax
, struct axs_value
*value
,
1150 struct axs_value
*value1
, struct axs_value
*value2
,
1151 struct type
*result_type
)
1153 if (pointer_type (value1
->type
) || pointer_type (value2
->type
))
1154 ax_simple (ax
, aop_equal
);
1156 gen_binop (ax
, value
, value1
, value2
,
1157 aop_equal
, aop_equal
, 0, "equal");
1158 value
->type
= result_type
;
1159 value
->kind
= axs_rvalue
;
1163 gen_less (struct agent_expr
*ax
, struct axs_value
*value
,
1164 struct axs_value
*value1
, struct axs_value
*value2
,
1165 struct type
*result_type
)
1167 if (pointer_type (value1
->type
) || pointer_type (value2
->type
))
1168 ax_simple (ax
, aop_less_unsigned
);
1170 gen_binop (ax
, value
, value1
, value2
,
1171 aop_less_signed
, aop_less_unsigned
, 0, "less than");
1172 value
->type
= result_type
;
1173 value
->kind
= axs_rvalue
;
1176 /* Generate code for a binary operator that doesn't do pointer magic.
1177 We set VALUE to describe the result value; we assume VALUE1 and
1178 VALUE2 describe the two operands, and that they've undergone the
1179 usual binary conversions. MAY_CARRY should be non-zero iff the
1180 result needs to be extended. NAME is the English name of the
1181 operator, used in error messages */
1183 gen_binop (struct agent_expr
*ax
, struct axs_value
*value
,
1184 struct axs_value
*value1
, struct axs_value
*value2
,
1185 enum agent_op op
, enum agent_op op_unsigned
,
1186 int may_carry
, char *name
)
1188 /* We only handle INT op INT. */
1189 if ((TYPE_CODE (value1
->type
) != TYPE_CODE_INT
)
1190 || (TYPE_CODE (value2
->type
) != TYPE_CODE_INT
))
1191 error (_("Invalid combination of types in %s."), name
);
1194 TYPE_UNSIGNED (value1
->type
) ? op_unsigned
: op
);
1196 gen_extend (ax
, value1
->type
); /* catch overflow */
1197 value
->type
= value1
->type
;
1198 value
->kind
= axs_rvalue
;
1203 gen_logical_not (struct agent_expr
*ax
, struct axs_value
*value
,
1204 struct type
*result_type
)
1206 if (TYPE_CODE (value
->type
) != TYPE_CODE_INT
1207 && TYPE_CODE (value
->type
) != TYPE_CODE_PTR
)
1208 error (_("Invalid type of operand to `!'."));
1210 ax_simple (ax
, aop_log_not
);
1211 value
->type
= result_type
;
1216 gen_complement (struct agent_expr
*ax
, struct axs_value
*value
)
1218 if (TYPE_CODE (value
->type
) != TYPE_CODE_INT
)
1219 error (_("Invalid type of operand to `~'."));
1221 ax_simple (ax
, aop_bit_not
);
1222 gen_extend (ax
, value
->type
);
1227 /* Generating bytecode from GDB expressions: * & . -> @ sizeof */
1229 /* Dereference the value on the top of the stack. */
1231 gen_deref (struct agent_expr
*ax
, struct axs_value
*value
)
1233 /* The caller should check the type, because several operators use
1234 this, and we don't know what error message to generate. */
1235 if (!pointer_type (value
->type
))
1236 internal_error (__FILE__
, __LINE__
,
1237 _("gen_deref: expected a pointer"));
1239 /* We've got an rvalue now, which is a pointer. We want to yield an
1240 lvalue, whose address is exactly that pointer. So we don't
1241 actually emit any code; we just change the type from "Pointer to
1242 T" to "T", and mark the value as an lvalue in memory. Leave it
1243 to the consumer to actually dereference it. */
1244 value
->type
= check_typedef (TYPE_TARGET_TYPE (value
->type
));
1245 if (TYPE_CODE (value
->type
) == TYPE_CODE_VOID
)
1246 error (_("Attempt to dereference a generic pointer."));
1247 value
->kind
= ((TYPE_CODE (value
->type
) == TYPE_CODE_FUNC
)
1248 ? axs_rvalue
: axs_lvalue_memory
);
1252 /* Produce the address of the lvalue on the top of the stack. */
1254 gen_address_of (struct agent_expr
*ax
, struct axs_value
*value
)
1256 /* Special case for taking the address of a function. The ANSI
1257 standard describes this as a special case, too, so this
1258 arrangement is not without motivation. */
1259 if (TYPE_CODE (value
->type
) == TYPE_CODE_FUNC
)
1260 /* The value's already an rvalue on the stack, so we just need to
1262 value
->type
= lookup_pointer_type (value
->type
);
1264 switch (value
->kind
)
1267 error (_("Operand of `&' is an rvalue, which has no address."));
1269 case axs_lvalue_register
:
1270 error (_("Operand of `&' is in a register, and has no address."));
1272 case axs_lvalue_memory
:
1273 value
->kind
= axs_rvalue
;
1274 value
->type
= lookup_pointer_type (value
->type
);
1279 /* Generate code to push the value of a bitfield of a structure whose
1280 address is on the top of the stack. START and END give the
1281 starting and one-past-ending *bit* numbers of the field within the
1284 gen_bitfield_ref (struct expression
*exp
, struct agent_expr
*ax
,
1285 struct axs_value
*value
, struct type
*type
,
1288 /* Note that ops[i] fetches 8 << i bits. */
1289 static enum agent_op ops
[]
1290 = {aop_ref8
, aop_ref16
, aop_ref32
, aop_ref64
};
1291 static int num_ops
= (sizeof (ops
) / sizeof (ops
[0]));
1293 /* We don't want to touch any byte that the bitfield doesn't
1294 actually occupy; we shouldn't make any accesses we're not
1295 explicitly permitted to. We rely here on the fact that the
1296 bytecode `ref' operators work on unaligned addresses.
1298 It takes some fancy footwork to get the stack to work the way
1299 we'd like. Say we're retrieving a bitfield that requires three
1300 fetches. Initially, the stack just contains the address:
1302 For the first fetch, we duplicate the address
1304 then add the byte offset, do the fetch, and shift and mask as
1305 needed, yielding a fragment of the value, properly aligned for
1306 the final bitwise or:
1308 then we swap, and repeat the process:
1309 frag1 addr --- address on top
1310 frag1 addr addr --- duplicate it
1311 frag1 addr frag2 --- get second fragment
1312 frag1 frag2 addr --- swap again
1313 frag1 frag2 frag3 --- get third fragment
1314 Notice that, since the third fragment is the last one, we don't
1315 bother duplicating the address this time. Now we have all the
1316 fragments on the stack, and we can simply `or' them together,
1317 yielding the final value of the bitfield. */
1319 /* The first and one-after-last bits in the field, but rounded down
1320 and up to byte boundaries. */
1321 int bound_start
= (start
/ TARGET_CHAR_BIT
) * TARGET_CHAR_BIT
;
1322 int bound_end
= (((end
+ TARGET_CHAR_BIT
- 1)
1326 /* current bit offset within the structure */
1329 /* The index in ops of the opcode we're considering. */
1332 /* The number of fragments we generated in the process. Probably
1333 equal to the number of `one' bits in bytesize, but who cares? */
1336 /* Dereference any typedefs. */
1337 type
= check_typedef (type
);
1339 /* Can we fetch the number of bits requested at all? */
1340 if ((end
- start
) > ((1 << num_ops
) * 8))
1341 internal_error (__FILE__
, __LINE__
,
1342 _("gen_bitfield_ref: bitfield too wide"));
1344 /* Note that we know here that we only need to try each opcode once.
1345 That may not be true on machines with weird byte sizes. */
1346 offset
= bound_start
;
1348 for (op
= num_ops
- 1; op
>= 0; op
--)
1350 /* number of bits that ops[op] would fetch */
1351 int op_size
= 8 << op
;
1353 /* The stack at this point, from bottom to top, contains zero or
1354 more fragments, then the address. */
1356 /* Does this fetch fit within the bitfield? */
1357 if (offset
+ op_size
<= bound_end
)
1359 /* Is this the last fragment? */
1360 int last_frag
= (offset
+ op_size
== bound_end
);
1363 ax_simple (ax
, aop_dup
); /* keep a copy of the address */
1365 /* Add the offset. */
1366 gen_offset (ax
, offset
/ TARGET_CHAR_BIT
);
1370 /* Record the area of memory we're about to fetch. */
1371 ax_trace_quick (ax
, op_size
/ TARGET_CHAR_BIT
);
1374 /* Perform the fetch. */
1375 ax_simple (ax
, ops
[op
]);
1377 /* Shift the bits we have to their proper position.
1378 gen_left_shift will generate right shifts when the operand
1381 A big-endian field diagram to ponder:
1382 byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 byte 6 byte 7
1383 +------++------++------++------++------++------++------++------+
1384 xxxxAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBCCCCCxxxxxxxxxxx
1386 bit number 16 32 48 53
1387 These are bit numbers as supplied by GDB. Note that the
1388 bit numbers run from right to left once you've fetched the
1391 A little-endian field diagram to ponder:
1392 byte 7 byte 6 byte 5 byte 4 byte 3 byte 2 byte 1 byte 0
1393 +------++------++------++------++------++------++------++------+
1394 xxxxxxxxxxxAAAAABBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCCCCCCCCCCCxxxx
1396 bit number 48 32 16 4 0
1398 In both cases, the most significant end is on the left
1399 (i.e. normal numeric writing order), which means that you
1400 don't go crazy thinking about `left' and `right' shifts.
1402 We don't have to worry about masking yet:
1403 - If they contain garbage off the least significant end, then we
1404 must be looking at the low end of the field, and the right
1405 shift will wipe them out.
1406 - If they contain garbage off the most significant end, then we
1407 must be looking at the most significant end of the word, and
1408 the sign/zero extension will wipe them out.
1409 - If we're in the interior of the word, then there is no garbage
1410 on either end, because the ref operators zero-extend. */
1411 if (gdbarch_byte_order (exp
->gdbarch
) == BFD_ENDIAN_BIG
)
1412 gen_left_shift (ax
, end
- (offset
+ op_size
));
1414 gen_left_shift (ax
, offset
- start
);
1417 /* Bring the copy of the address up to the top. */
1418 ax_simple (ax
, aop_swap
);
1425 /* Generate enough bitwise `or' operations to combine all the
1426 fragments we left on the stack. */
1427 while (fragment_count
-- > 1)
1428 ax_simple (ax
, aop_bit_or
);
1430 /* Sign- or zero-extend the value as appropriate. */
1431 ((TYPE_UNSIGNED (type
) ? ax_zero_ext
: ax_ext
) (ax
, end
- start
));
1433 /* This is *not* an lvalue. Ugh. */
1434 value
->kind
= axs_rvalue
;
1438 /* Generate bytecodes for field number FIELDNO of type TYPE. OFFSET
1439 is an accumulated offset (in bytes), will be nonzero for objects
1440 embedded in other objects, like C++ base classes. Behavior should
1441 generally follow value_primitive_field. */
1444 gen_primitive_field (struct expression
*exp
,
1445 struct agent_expr
*ax
, struct axs_value
*value
,
1446 int offset
, int fieldno
, struct type
*type
)
1448 /* Is this a bitfield? */
1449 if (TYPE_FIELD_PACKED (type
, fieldno
))
1450 gen_bitfield_ref (exp
, ax
, value
, TYPE_FIELD_TYPE (type
, fieldno
),
1451 (offset
* TARGET_CHAR_BIT
1452 + TYPE_FIELD_BITPOS (type
, fieldno
)),
1453 (offset
* TARGET_CHAR_BIT
1454 + TYPE_FIELD_BITPOS (type
, fieldno
)
1455 + TYPE_FIELD_BITSIZE (type
, fieldno
)));
1458 gen_offset (ax
, offset
1459 + TYPE_FIELD_BITPOS (type
, fieldno
) / TARGET_CHAR_BIT
);
1460 value
->kind
= axs_lvalue_memory
;
1461 value
->type
= TYPE_FIELD_TYPE (type
, fieldno
);
1465 /* Search for the given field in either the given type or one of its
1466 base classes. Return 1 if found, 0 if not. */
1469 gen_struct_ref_recursive (struct expression
*exp
, struct agent_expr
*ax
,
1470 struct axs_value
*value
,
1471 char *field
, int offset
, struct type
*type
)
1474 int nbases
= TYPE_N_BASECLASSES (type
);
1476 CHECK_TYPEDEF (type
);
1478 for (i
= TYPE_NFIELDS (type
) - 1; i
>= nbases
; i
--)
1480 char *this_name
= TYPE_FIELD_NAME (type
, i
);
1484 if (strcmp (field
, this_name
) == 0)
1486 /* Note that bytecodes for the struct's base (aka
1487 "this") will have been generated already, which will
1488 be unnecessary but not harmful if the static field is
1489 being handled as a global. */
1490 if (field_is_static (&TYPE_FIELD (type
, i
)))
1492 gen_static_field (exp
->gdbarch
, ax
, value
, type
, i
);
1493 if (value
->optimized_out
)
1494 error (_("static field `%s' has been "
1495 "optimized out, cannot use"),
1500 gen_primitive_field (exp
, ax
, value
, offset
, i
, type
);
1503 #if 0 /* is this right? */
1504 if (this_name
[0] == '\0')
1505 internal_error (__FILE__
, __LINE__
,
1506 _("find_field: anonymous unions not supported"));
1511 /* Now scan through base classes recursively. */
1512 for (i
= 0; i
< nbases
; i
++)
1514 struct type
*basetype
= check_typedef (TYPE_BASECLASS (type
, i
));
1516 rslt
= gen_struct_ref_recursive (exp
, ax
, value
, field
,
1517 offset
+ TYPE_BASECLASS_BITPOS (type
, i
)
1524 /* Not found anywhere, flag so caller can complain. */
1528 /* Generate code to reference the member named FIELD of a structure or
1529 union. The top of the stack, as described by VALUE, should have
1530 type (pointer to a)* struct/union. OPERATOR_NAME is the name of
1531 the operator being compiled, and OPERAND_NAME is the kind of thing
1532 it operates on; we use them in error messages. */
1534 gen_struct_ref (struct expression
*exp
, struct agent_expr
*ax
,
1535 struct axs_value
*value
, char *field
,
1536 char *operator_name
, char *operand_name
)
1541 /* Follow pointers until we reach a non-pointer. These aren't the C
1542 semantics, but they're what the normal GDB evaluator does, so we
1543 should at least be consistent. */
1544 while (pointer_type (value
->type
))
1546 require_rvalue (ax
, value
);
1547 gen_deref (ax
, value
);
1549 type
= check_typedef (value
->type
);
1551 /* This must yield a structure or a union. */
1552 if (TYPE_CODE (type
) != TYPE_CODE_STRUCT
1553 && TYPE_CODE (type
) != TYPE_CODE_UNION
)
1554 error (_("The left operand of `%s' is not a %s."),
1555 operator_name
, operand_name
);
1557 /* And it must be in memory; we don't deal with structure rvalues,
1558 or structures living in registers. */
1559 if (value
->kind
!= axs_lvalue_memory
)
1560 error (_("Structure does not live in memory."));
1562 /* Search through fields and base classes recursively. */
1563 found
= gen_struct_ref_recursive (exp
, ax
, value
, field
, 0, type
);
1566 error (_("Couldn't find member named `%s' in struct/union/class `%s'"),
1567 field
, TYPE_TAG_NAME (type
));
1571 gen_namespace_elt (struct expression
*exp
,
1572 struct agent_expr
*ax
, struct axs_value
*value
,
1573 const struct type
*curtype
, char *name
);
1575 gen_maybe_namespace_elt (struct expression
*exp
,
1576 struct agent_expr
*ax
, struct axs_value
*value
,
1577 const struct type
*curtype
, char *name
);
1580 gen_static_field (struct gdbarch
*gdbarch
,
1581 struct agent_expr
*ax
, struct axs_value
*value
,
1582 struct type
*type
, int fieldno
)
1584 if (TYPE_FIELD_LOC_KIND (type
, fieldno
) == FIELD_LOC_KIND_PHYSADDR
)
1586 ax_const_l (ax
, TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1587 value
->kind
= axs_lvalue_memory
;
1588 value
->type
= TYPE_FIELD_TYPE (type
, fieldno
);
1589 value
->optimized_out
= 0;
1593 const char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1594 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1598 gen_var_ref (gdbarch
, ax
, value
, sym
);
1600 /* Don't error if the value was optimized out, we may be
1601 scanning all static fields and just want to pass over this
1602 and continue with the rest. */
1606 /* Silently assume this was optimized out; class printing
1607 will let the user know why the data is missing. */
1608 value
->optimized_out
= 1;
1614 gen_struct_elt_for_reference (struct expression
*exp
,
1615 struct agent_expr
*ax
, struct axs_value
*value
,
1616 struct type
*type
, char *fieldname
)
1618 struct type
*t
= type
;
1621 if (TYPE_CODE (t
) != TYPE_CODE_STRUCT
1622 && TYPE_CODE (t
) != TYPE_CODE_UNION
)
1623 internal_error (__FILE__
, __LINE__
,
1624 _("non-aggregate type to gen_struct_elt_for_reference"));
1626 for (i
= TYPE_NFIELDS (t
) - 1; i
>= TYPE_N_BASECLASSES (t
); i
--)
1628 char *t_field_name
= TYPE_FIELD_NAME (t
, i
);
1630 if (t_field_name
&& strcmp (t_field_name
, fieldname
) == 0)
1632 if (field_is_static (&TYPE_FIELD (t
, i
)))
1634 gen_static_field (exp
->gdbarch
, ax
, value
, t
, i
);
1635 if (value
->optimized_out
)
1636 error (_("static field `%s' has been "
1637 "optimized out, cannot use"),
1641 if (TYPE_FIELD_PACKED (t
, i
))
1642 error (_("pointers to bitfield members not allowed"));
1644 /* FIXME we need a way to do "want_address" equivalent */
1646 error (_("Cannot reference non-static field \"%s\""), fieldname
);
1650 /* FIXME add other scoped-reference cases here */
1652 /* Do a last-ditch lookup. */
1653 return gen_maybe_namespace_elt (exp
, ax
, value
, type
, fieldname
);
1656 /* C++: Return the member NAME of the namespace given by the type
1660 gen_namespace_elt (struct expression
*exp
,
1661 struct agent_expr
*ax
, struct axs_value
*value
,
1662 const struct type
*curtype
, char *name
)
1664 int found
= gen_maybe_namespace_elt (exp
, ax
, value
, curtype
, name
);
1667 error (_("No symbol \"%s\" in namespace \"%s\"."),
1668 name
, TYPE_TAG_NAME (curtype
));
1673 /* A helper function used by value_namespace_elt and
1674 value_struct_elt_for_reference. It looks up NAME inside the
1675 context CURTYPE; this works if CURTYPE is a namespace or if CURTYPE
1676 is a class and NAME refers to a type in CURTYPE itself (as opposed
1677 to, say, some base class of CURTYPE). */
1680 gen_maybe_namespace_elt (struct expression
*exp
,
1681 struct agent_expr
*ax
, struct axs_value
*value
,
1682 const struct type
*curtype
, char *name
)
1684 const char *namespace_name
= TYPE_TAG_NAME (curtype
);
1687 sym
= cp_lookup_symbol_namespace (namespace_name
, name
,
1688 block_for_pc (ax
->scope
),
1694 gen_var_ref (exp
->gdbarch
, ax
, value
, sym
);
1696 if (value
->optimized_out
)
1697 error (_("`%s' has been optimized out, cannot use"),
1698 SYMBOL_PRINT_NAME (sym
));
1705 gen_aggregate_elt_ref (struct expression
*exp
,
1706 struct agent_expr
*ax
, struct axs_value
*value
,
1707 struct type
*type
, char *field
,
1708 char *operator_name
, char *operand_name
)
1710 switch (TYPE_CODE (type
))
1712 case TYPE_CODE_STRUCT
:
1713 case TYPE_CODE_UNION
:
1714 return gen_struct_elt_for_reference (exp
, ax
, value
, type
, field
);
1716 case TYPE_CODE_NAMESPACE
:
1717 return gen_namespace_elt (exp
, ax
, value
, type
, field
);
1720 internal_error (__FILE__
, __LINE__
,
1721 _("non-aggregate type in gen_aggregate_elt_ref"));
1727 /* Generate code for GDB's magical `repeat' operator.
1728 LVALUE @ INT creates an array INT elements long, and whose elements
1729 have the same type as LVALUE, located in memory so that LVALUE is
1730 its first element. For example, argv[0]@argc gives you the array
1731 of command-line arguments.
1733 Unfortunately, because we have to know the types before we actually
1734 have a value for the expression, we can't implement this perfectly
1735 without changing the type system, having values that occupy two
1736 stack slots, doing weird things with sizeof, etc. So we require
1737 the right operand to be a constant expression. */
1739 gen_repeat (struct expression
*exp
, union exp_element
**pc
,
1740 struct agent_expr
*ax
, struct axs_value
*value
)
1742 struct axs_value value1
;
1744 /* We don't want to turn this into an rvalue, so no conversions
1746 gen_expr (exp
, pc
, ax
, &value1
);
1747 if (value1
.kind
!= axs_lvalue_memory
)
1748 error (_("Left operand of `@' must be an object in memory."));
1750 /* Evaluate the length; it had better be a constant. */
1752 struct value
*v
= const_expr (pc
);
1756 error (_("Right operand of `@' must be a "
1757 "constant, in agent expressions."));
1758 if (TYPE_CODE (value_type (v
)) != TYPE_CODE_INT
)
1759 error (_("Right operand of `@' must be an integer."));
1760 length
= value_as_long (v
);
1762 error (_("Right operand of `@' must be positive."));
1764 /* The top of the stack is already the address of the object, so
1765 all we need to do is frob the type of the lvalue. */
1767 /* FIXME-type-allocation: need a way to free this type when we are
1770 = lookup_array_range_type (value1
.type
, 0, length
- 1);
1772 value
->kind
= axs_lvalue_memory
;
1773 value
->type
= array
;
1779 /* Emit code for the `sizeof' operator.
1780 *PC should point at the start of the operand expression; we advance it
1781 to the first instruction after the operand. */
1783 gen_sizeof (struct expression
*exp
, union exp_element
**pc
,
1784 struct agent_expr
*ax
, struct axs_value
*value
,
1785 struct type
*size_type
)
1787 /* We don't care about the value of the operand expression; we only
1788 care about its type. However, in the current arrangement, the
1789 only way to find an expression's type is to generate code for it.
1790 So we generate code for the operand, and then throw it away,
1791 replacing it with code that simply pushes its size. */
1792 int start
= ax
->len
;
1794 gen_expr (exp
, pc
, ax
, value
);
1796 /* Throw away the code we just generated. */
1799 ax_const_l (ax
, TYPE_LENGTH (value
->type
));
1800 value
->kind
= axs_rvalue
;
1801 value
->type
= size_type
;
1805 /* Generating bytecode from GDB expressions: general recursive thingy */
1808 /* A gen_expr function written by a Gen-X'er guy.
1809 Append code for the subexpression of EXPR starting at *POS_P to AX. */
1811 gen_expr (struct expression
*exp
, union exp_element
**pc
,
1812 struct agent_expr
*ax
, struct axs_value
*value
)
1814 /* Used to hold the descriptions of operand expressions. */
1815 struct axs_value value1
, value2
, value3
;
1816 enum exp_opcode op
= (*pc
)[0].opcode
, op2
;
1817 int if1
, go1
, if2
, go2
, end
;
1818 struct type
*int_type
= builtin_type (exp
->gdbarch
)->builtin_int
;
1820 /* If we're looking at a constant expression, just push its value. */
1822 struct value
*v
= maybe_const_expr (pc
);
1826 ax_const_l (ax
, value_as_long (v
));
1827 value
->kind
= axs_rvalue
;
1828 value
->type
= check_typedef (value_type (v
));
1833 /* Otherwise, go ahead and generate code for it. */
1836 /* Binary arithmetic operators. */
1844 case BINOP_SUBSCRIPT
:
1845 case BINOP_BITWISE_AND
:
1846 case BINOP_BITWISE_IOR
:
1847 case BINOP_BITWISE_XOR
:
1849 case BINOP_NOTEQUAL
:
1855 gen_expr (exp
, pc
, ax
, &value1
);
1856 gen_usual_unary (exp
, ax
, &value1
);
1857 gen_expr_binop_rest (exp
, op
, pc
, ax
, value
, &value1
, &value2
);
1860 case BINOP_LOGICAL_AND
:
1862 /* Generate the obvious sequence of tests and jumps. */
1863 gen_expr (exp
, pc
, ax
, &value1
);
1864 gen_usual_unary (exp
, ax
, &value1
);
1865 if1
= ax_goto (ax
, aop_if_goto
);
1866 go1
= ax_goto (ax
, aop_goto
);
1867 ax_label (ax
, if1
, ax
->len
);
1868 gen_expr (exp
, pc
, ax
, &value2
);
1869 gen_usual_unary (exp
, ax
, &value2
);
1870 if2
= ax_goto (ax
, aop_if_goto
);
1871 go2
= ax_goto (ax
, aop_goto
);
1872 ax_label (ax
, if2
, ax
->len
);
1874 end
= ax_goto (ax
, aop_goto
);
1875 ax_label (ax
, go1
, ax
->len
);
1876 ax_label (ax
, go2
, ax
->len
);
1878 ax_label (ax
, end
, ax
->len
);
1879 value
->kind
= axs_rvalue
;
1880 value
->type
= int_type
;
1883 case BINOP_LOGICAL_OR
:
1885 /* Generate the obvious sequence of tests and jumps. */
1886 gen_expr (exp
, pc
, ax
, &value1
);
1887 gen_usual_unary (exp
, ax
, &value1
);
1888 if1
= ax_goto (ax
, aop_if_goto
);
1889 gen_expr (exp
, pc
, ax
, &value2
);
1890 gen_usual_unary (exp
, ax
, &value2
);
1891 if2
= ax_goto (ax
, aop_if_goto
);
1893 end
= ax_goto (ax
, aop_goto
);
1894 ax_label (ax
, if1
, ax
->len
);
1895 ax_label (ax
, if2
, ax
->len
);
1897 ax_label (ax
, end
, ax
->len
);
1898 value
->kind
= axs_rvalue
;
1899 value
->type
= int_type
;
1904 gen_expr (exp
, pc
, ax
, &value1
);
1905 gen_usual_unary (exp
, ax
, &value1
);
1906 /* For (A ? B : C), it's easiest to generate subexpression
1907 bytecodes in order, but if_goto jumps on true, so we invert
1908 the sense of A. Then we can do B by dropping through, and
1910 gen_logical_not (ax
, &value1
, int_type
);
1911 if1
= ax_goto (ax
, aop_if_goto
);
1912 gen_expr (exp
, pc
, ax
, &value2
);
1913 gen_usual_unary (exp
, ax
, &value2
);
1914 end
= ax_goto (ax
, aop_goto
);
1915 ax_label (ax
, if1
, ax
->len
);
1916 gen_expr (exp
, pc
, ax
, &value3
);
1917 gen_usual_unary (exp
, ax
, &value3
);
1918 ax_label (ax
, end
, ax
->len
);
1919 /* This is arbitary - what if B and C are incompatible types? */
1920 value
->type
= value2
.type
;
1921 value
->kind
= value2
.kind
;
1926 if ((*pc
)[0].opcode
== OP_INTERNALVAR
)
1928 char *name
= internalvar_name ((*pc
)[1].internalvar
);
1929 struct trace_state_variable
*tsv
;
1932 gen_expr (exp
, pc
, ax
, value
);
1933 tsv
= find_trace_state_variable (name
);
1936 ax_tsv (ax
, aop_setv
, tsv
->number
);
1938 ax_tsv (ax
, aop_tracev
, tsv
->number
);
1941 error (_("$%s is not a trace state variable, "
1942 "may not assign to it"), name
);
1945 error (_("May only assign to trace state variables"));
1948 case BINOP_ASSIGN_MODIFY
:
1950 op2
= (*pc
)[0].opcode
;
1953 if ((*pc
)[0].opcode
== OP_INTERNALVAR
)
1955 char *name
= internalvar_name ((*pc
)[1].internalvar
);
1956 struct trace_state_variable
*tsv
;
1959 tsv
= find_trace_state_variable (name
);
1962 /* The tsv will be the left half of the binary operation. */
1963 ax_tsv (ax
, aop_getv
, tsv
->number
);
1965 ax_tsv (ax
, aop_tracev
, tsv
->number
);
1966 /* Trace state variables are always 64-bit integers. */
1967 value1
.kind
= axs_rvalue
;
1968 value1
.type
= builtin_type (exp
->gdbarch
)->builtin_long_long
;
1969 /* Now do right half of expression. */
1970 gen_expr_binop_rest (exp
, op2
, pc
, ax
, value
, &value1
, &value2
);
1971 /* We have a result of the binary op, set the tsv. */
1972 ax_tsv (ax
, aop_setv
, tsv
->number
);
1974 ax_tsv (ax
, aop_tracev
, tsv
->number
);
1977 error (_("$%s is not a trace state variable, "
1978 "may not assign to it"), name
);
1981 error (_("May only assign to trace state variables"));
1984 /* Note that we need to be a little subtle about generating code
1985 for comma. In C, we can do some optimizations here because
1986 we know the left operand is only being evaluated for effect.
1987 However, if the tracing kludge is in effect, then we always
1988 need to evaluate the left hand side fully, so that all the
1989 variables it mentions get traced. */
1992 gen_expr (exp
, pc
, ax
, &value1
);
1993 /* Don't just dispose of the left operand. We might be tracing,
1994 in which case we want to emit code to trace it if it's an
1996 gen_traced_pop (exp
->gdbarch
, ax
, &value1
);
1997 gen_expr (exp
, pc
, ax
, value
);
1998 /* It's the consumer's responsibility to trace the right operand. */
2001 case OP_LONG
: /* some integer constant */
2003 struct type
*type
= (*pc
)[1].type
;
2004 LONGEST k
= (*pc
)[2].longconst
;
2007 gen_int_literal (ax
, value
, k
, type
);
2012 gen_var_ref (exp
->gdbarch
, ax
, value
, (*pc
)[2].symbol
);
2014 if (value
->optimized_out
)
2015 error (_("`%s' has been optimized out, cannot use"),
2016 SYMBOL_PRINT_NAME ((*pc
)[2].symbol
));
2023 const char *name
= &(*pc
)[2].string
;
2026 (*pc
) += 4 + BYTES_TO_EXP_ELEM ((*pc
)[1].longconst
+ 1);
2027 reg
= user_reg_map_name_to_regnum (exp
->gdbarch
, name
, strlen (name
));
2029 internal_error (__FILE__
, __LINE__
,
2030 _("Register $%s not available"), name
);
2031 /* No support for tracing user registers yet. */
2032 if (reg
>= gdbarch_num_regs (exp
->gdbarch
)
2033 + gdbarch_num_pseudo_regs (exp
->gdbarch
))
2034 error (_("'%s' is a user-register; "
2035 "GDB cannot yet trace user-register contents."),
2037 value
->kind
= axs_lvalue_register
;
2039 value
->type
= register_type (exp
->gdbarch
, reg
);
2043 case OP_INTERNALVAR
:
2045 const char *name
= internalvar_name ((*pc
)[1].internalvar
);
2046 struct trace_state_variable
*tsv
;
2049 tsv
= find_trace_state_variable (name
);
2052 ax_tsv (ax
, aop_getv
, tsv
->number
);
2054 ax_tsv (ax
, aop_tracev
, tsv
->number
);
2055 /* Trace state variables are always 64-bit integers. */
2056 value
->kind
= axs_rvalue
;
2057 value
->type
= builtin_type (exp
->gdbarch
)->builtin_long_long
;
2060 error (_("$%s is not a trace state variable; GDB agent "
2061 "expressions cannot use convenience variables."), name
);
2065 /* Weirdo operator: see comments for gen_repeat for details. */
2067 /* Note that gen_repeat handles its own argument evaluation. */
2069 gen_repeat (exp
, pc
, ax
, value
);
2074 struct type
*type
= (*pc
)[1].type
;
2077 gen_expr (exp
, pc
, ax
, value
);
2078 gen_cast (ax
, value
, type
);
2084 struct type
*type
= check_typedef ((*pc
)[1].type
);
2087 gen_expr (exp
, pc
, ax
, value
);
2089 /* If we have an axs_rvalue or an axs_lvalue_memory, then we
2090 already have the right value on the stack. For
2091 axs_lvalue_register, we must convert. */
2092 if (value
->kind
== axs_lvalue_register
)
2093 require_rvalue (ax
, value
);
2096 value
->kind
= axs_lvalue_memory
;
2102 /* + FOO is equivalent to 0 + FOO, which can be optimized. */
2103 gen_expr (exp
, pc
, ax
, value
);
2104 gen_usual_unary (exp
, ax
, value
);
2109 /* -FOO is equivalent to 0 - FOO. */
2110 gen_int_literal (ax
, &value1
, 0,
2111 builtin_type (exp
->gdbarch
)->builtin_int
);
2112 gen_usual_unary (exp
, ax
, &value1
); /* shouldn't do much */
2113 gen_expr (exp
, pc
, ax
, &value2
);
2114 gen_usual_unary (exp
, ax
, &value2
);
2115 gen_usual_arithmetic (exp
, ax
, &value1
, &value2
);
2116 gen_binop (ax
, value
, &value1
, &value2
, aop_sub
, aop_sub
, 1, "negation");
2119 case UNOP_LOGICAL_NOT
:
2121 gen_expr (exp
, pc
, ax
, value
);
2122 gen_usual_unary (exp
, ax
, value
);
2123 gen_logical_not (ax
, value
, int_type
);
2126 case UNOP_COMPLEMENT
:
2128 gen_expr (exp
, pc
, ax
, value
);
2129 gen_usual_unary (exp
, ax
, value
);
2130 gen_integral_promotions (exp
, ax
, value
);
2131 gen_complement (ax
, value
);
2136 gen_expr (exp
, pc
, ax
, value
);
2137 gen_usual_unary (exp
, ax
, value
);
2138 if (!pointer_type (value
->type
))
2139 error (_("Argument of unary `*' is not a pointer."));
2140 gen_deref (ax
, value
);
2145 gen_expr (exp
, pc
, ax
, value
);
2146 gen_address_of (ax
, value
);
2151 /* Notice that gen_sizeof handles its own operand, unlike most
2152 of the other unary operator functions. This is because we
2153 have to throw away the code we generate. */
2154 gen_sizeof (exp
, pc
, ax
, value
,
2155 builtin_type (exp
->gdbarch
)->builtin_int
);
2158 case STRUCTOP_STRUCT
:
2161 int length
= (*pc
)[1].longconst
;
2162 char *name
= &(*pc
)[2].string
;
2164 (*pc
) += 4 + BYTES_TO_EXP_ELEM (length
+ 1);
2165 gen_expr (exp
, pc
, ax
, value
);
2166 if (op
== STRUCTOP_STRUCT
)
2167 gen_struct_ref (exp
, ax
, value
, name
, ".", "structure or union");
2168 else if (op
== STRUCTOP_PTR
)
2169 gen_struct_ref (exp
, ax
, value
, name
, "->",
2170 "pointer to a structure or union");
2172 /* If this `if' chain doesn't handle it, then the case list
2173 shouldn't mention it, and we shouldn't be here. */
2174 internal_error (__FILE__
, __LINE__
,
2175 _("gen_expr: unhandled struct case"));
2182 struct symbol
*sym
, *func
;
2184 const struct language_defn
*lang
;
2186 b
= block_for_pc (ax
->scope
);
2187 func
= block_linkage_function (b
);
2188 lang
= language_def (SYMBOL_LANGUAGE (func
));
2190 sym
= lookup_language_this (lang
, b
);
2192 error (_("no `%s' found"), lang
->la_name_of_this
);
2194 gen_var_ref (exp
->gdbarch
, ax
, value
, sym
);
2196 if (value
->optimized_out
)
2197 error (_("`%s' has been optimized out, cannot use"),
2198 SYMBOL_PRINT_NAME (sym
));
2206 struct type
*type
= (*pc
)[1].type
;
2207 int length
= longest_to_int ((*pc
)[2].longconst
);
2208 char *name
= &(*pc
)[3].string
;
2211 found
= gen_aggregate_elt_ref (exp
, ax
, value
, type
, name
,
2214 error (_("There is no field named %s"), name
);
2215 (*pc
) += 5 + BYTES_TO_EXP_ELEM (length
+ 1);
2220 error (_("Attempt to use a type name as an expression."));
2223 error (_("Unsupported operator %s (%d) in expression."),
2224 op_string (op
), op
);
2228 /* This handles the middle-to-right-side of code generation for binary
2229 expressions, which is shared between regular binary operations and
2230 assign-modify (+= and friends) expressions. */
2233 gen_expr_binop_rest (struct expression
*exp
,
2234 enum exp_opcode op
, union exp_element
**pc
,
2235 struct agent_expr
*ax
, struct axs_value
*value
,
2236 struct axs_value
*value1
, struct axs_value
*value2
)
2238 struct type
*int_type
= builtin_type (exp
->gdbarch
)->builtin_int
;
2240 gen_expr (exp
, pc
, ax
, value2
);
2241 gen_usual_unary (exp
, ax
, value2
);
2242 gen_usual_arithmetic (exp
, ax
, value1
, value2
);
2246 if (TYPE_CODE (value1
->type
) == TYPE_CODE_INT
2247 && pointer_type (value2
->type
))
2249 /* Swap the values and proceed normally. */
2250 ax_simple (ax
, aop_swap
);
2251 gen_ptradd (ax
, value
, value2
, value1
);
2253 else if (pointer_type (value1
->type
)
2254 && TYPE_CODE (value2
->type
) == TYPE_CODE_INT
)
2255 gen_ptradd (ax
, value
, value1
, value2
);
2257 gen_binop (ax
, value
, value1
, value2
,
2258 aop_add
, aop_add
, 1, "addition");
2261 if (pointer_type (value1
->type
)
2262 && TYPE_CODE (value2
->type
) == TYPE_CODE_INT
)
2263 gen_ptrsub (ax
,value
, value1
, value2
);
2264 else if (pointer_type (value1
->type
)
2265 && pointer_type (value2
->type
))
2266 /* FIXME --- result type should be ptrdiff_t */
2267 gen_ptrdiff (ax
, value
, value1
, value2
,
2268 builtin_type (exp
->gdbarch
)->builtin_long
);
2270 gen_binop (ax
, value
, value1
, value2
,
2271 aop_sub
, aop_sub
, 1, "subtraction");
2274 gen_binop (ax
, value
, value1
, value2
,
2275 aop_mul
, aop_mul
, 1, "multiplication");
2278 gen_binop (ax
, value
, value1
, value2
,
2279 aop_div_signed
, aop_div_unsigned
, 1, "division");
2282 gen_binop (ax
, value
, value1
, value2
,
2283 aop_rem_signed
, aop_rem_unsigned
, 1, "remainder");
2286 gen_binop (ax
, value
, value1
, value2
,
2287 aop_lsh
, aop_lsh
, 1, "left shift");
2290 gen_binop (ax
, value
, value1
, value2
,
2291 aop_rsh_signed
, aop_rsh_unsigned
, 1, "right shift");
2293 case BINOP_SUBSCRIPT
:
2297 if (binop_types_user_defined_p (op
, value1
->type
, value2
->type
))
2299 error (_("cannot subscript requested type: "
2300 "cannot call user defined functions"));
2304 /* If the user attempts to subscript something that is not
2305 an array or pointer type (like a plain int variable for
2306 example), then report this as an error. */
2307 type
= check_typedef (value1
->type
);
2308 if (TYPE_CODE (type
) != TYPE_CODE_ARRAY
2309 && TYPE_CODE (type
) != TYPE_CODE_PTR
)
2311 if (TYPE_NAME (type
))
2312 error (_("cannot subscript something of type `%s'"),
2315 error (_("cannot subscript requested type"));
2319 if (!is_integral_type (value2
->type
))
2320 error (_("Argument to arithmetic operation "
2321 "not a number or boolean."));
2323 gen_ptradd (ax
, value
, value1
, value2
);
2324 gen_deref (ax
, value
);
2327 case BINOP_BITWISE_AND
:
2328 gen_binop (ax
, value
, value1
, value2
,
2329 aop_bit_and
, aop_bit_and
, 0, "bitwise and");
2332 case BINOP_BITWISE_IOR
:
2333 gen_binop (ax
, value
, value1
, value2
,
2334 aop_bit_or
, aop_bit_or
, 0, "bitwise or");
2337 case BINOP_BITWISE_XOR
:
2338 gen_binop (ax
, value
, value1
, value2
,
2339 aop_bit_xor
, aop_bit_xor
, 0, "bitwise exclusive-or");
2343 gen_equal (ax
, value
, value1
, value2
, int_type
);
2346 case BINOP_NOTEQUAL
:
2347 gen_equal (ax
, value
, value1
, value2
, int_type
);
2348 gen_logical_not (ax
, value
, int_type
);
2352 gen_less (ax
, value
, value1
, value2
, int_type
);
2356 ax_simple (ax
, aop_swap
);
2357 gen_less (ax
, value
, value1
, value2
, int_type
);
2361 ax_simple (ax
, aop_swap
);
2362 gen_less (ax
, value
, value1
, value2
, int_type
);
2363 gen_logical_not (ax
, value
, int_type
);
2367 gen_less (ax
, value
, value1
, value2
, int_type
);
2368 gen_logical_not (ax
, value
, int_type
);
2372 /* We should only list operators in the outer case statement
2373 that we actually handle in the inner case statement. */
2374 internal_error (__FILE__
, __LINE__
,
2375 _("gen_expr: op case sets don't match"));
2380 /* Given a single variable and a scope, generate bytecodes to trace
2381 its value. This is for use in situations where we have only a
2382 variable's name, and no parsed expression; for instance, when the
2383 name comes from a list of local variables of a function. */
2386 gen_trace_for_var (CORE_ADDR scope
, struct gdbarch
*gdbarch
,
2389 struct cleanup
*old_chain
= 0;
2390 struct agent_expr
*ax
= new_agent_expr (gdbarch
, scope
);
2391 struct axs_value value
;
2393 old_chain
= make_cleanup_free_agent_expr (ax
);
2396 gen_var_ref (gdbarch
, ax
, &value
, var
);
2398 /* If there is no actual variable to trace, flag it by returning
2399 an empty agent expression. */
2400 if (value
.optimized_out
)
2402 do_cleanups (old_chain
);
2406 /* Make sure we record the final object, and get rid of it. */
2407 gen_traced_pop (gdbarch
, ax
, &value
);
2409 /* Oh, and terminate. */
2410 ax_simple (ax
, aop_end
);
2412 /* We have successfully built the agent expr, so cancel the cleanup
2413 request. If we add more cleanups that we always want done, this
2414 will have to get more complicated. */
2415 discard_cleanups (old_chain
);
2419 /* Generating bytecode from GDB expressions: driver */
2421 /* Given a GDB expression EXPR, return bytecode to trace its value.
2422 The result will use the `trace' and `trace_quick' bytecodes to
2423 record the value of all memory touched by the expression. The
2424 caller can then use the ax_reqs function to discover which
2425 registers it relies upon. */
2427 gen_trace_for_expr (CORE_ADDR scope
, struct expression
*expr
)
2429 struct cleanup
*old_chain
= 0;
2430 struct agent_expr
*ax
= new_agent_expr (expr
->gdbarch
, scope
);
2431 union exp_element
*pc
;
2432 struct axs_value value
;
2434 old_chain
= make_cleanup_free_agent_expr (ax
);
2438 value
.optimized_out
= 0;
2439 gen_expr (expr
, &pc
, ax
, &value
);
2441 /* Make sure we record the final object, and get rid of it. */
2442 gen_traced_pop (expr
->gdbarch
, ax
, &value
);
2444 /* Oh, and terminate. */
2445 ax_simple (ax
, aop_end
);
2447 /* We have successfully built the agent expr, so cancel the cleanup
2448 request. If we add more cleanups that we always want done, this
2449 will have to get more complicated. */
2450 discard_cleanups (old_chain
);
2454 /* Given a GDB expression EXPR, return a bytecode sequence that will
2455 evaluate and return a result. The bytecodes will do a direct
2456 evaluation, using the current data on the target, rather than
2457 recording blocks of memory and registers for later use, as
2458 gen_trace_for_expr does. The generated bytecode sequence leaves
2459 the result of expression evaluation on the top of the stack. */
2462 gen_eval_for_expr (CORE_ADDR scope
, struct expression
*expr
)
2464 struct cleanup
*old_chain
= 0;
2465 struct agent_expr
*ax
= new_agent_expr (expr
->gdbarch
, scope
);
2466 union exp_element
*pc
;
2467 struct axs_value value
;
2469 old_chain
= make_cleanup_free_agent_expr (ax
);
2473 value
.optimized_out
= 0;
2474 gen_expr (expr
, &pc
, ax
, &value
);
2476 require_rvalue (ax
, &value
);
2478 /* Oh, and terminate. */
2479 ax_simple (ax
, aop_end
);
2481 /* We have successfully built the agent expr, so cancel the cleanup
2482 request. If we add more cleanups that we always want done, this
2483 will have to get more complicated. */
2484 discard_cleanups (old_chain
);
2489 gen_trace_for_return_address (CORE_ADDR scope
, struct gdbarch
*gdbarch
)
2491 struct cleanup
*old_chain
= 0;
2492 struct agent_expr
*ax
= new_agent_expr (gdbarch
, scope
);
2493 struct axs_value value
;
2495 old_chain
= make_cleanup_free_agent_expr (ax
);
2499 gdbarch_gen_return_address (gdbarch
, ax
, &value
, scope
);
2501 /* Make sure we record the final object, and get rid of it. */
2502 gen_traced_pop (gdbarch
, ax
, &value
);
2504 /* Oh, and terminate. */
2505 ax_simple (ax
, aop_end
);
2507 /* We have successfully built the agent expr, so cancel the cleanup
2508 request. If we add more cleanups that we always want done, this
2509 will have to get more complicated. */
2510 discard_cleanups (old_chain
);
2515 agent_command (char *exp
, int from_tty
)
2517 struct cleanup
*old_chain
= 0;
2518 struct expression
*expr
;
2519 struct agent_expr
*agent
;
2520 struct frame_info
*fi
= get_current_frame (); /* need current scope */
2522 /* We don't deal with overlay debugging at the moment. We need to
2523 think more carefully about this. If you copy this code into
2524 another command, change the error message; the user shouldn't
2525 have to know anything about agent expressions. */
2526 if (overlay_debugging
)
2527 error (_("GDB can't do agent expression translation with overlays."));
2530 error_no_arg (_("expression to translate"));
2532 trace_string_kludge
= 0;
2534 exp
= decode_agent_options (exp
);
2536 /* Recognize the return address collection directive specially. Note
2537 that it is not really an expression of any sort. */
2538 if (strcmp (exp
, "$_ret") == 0)
2540 agent
= gen_trace_for_return_address (get_frame_pc (fi
),
2541 get_current_arch ());
2542 old_chain
= make_cleanup_free_agent_expr (agent
);
2546 expr
= parse_expression (exp
);
2547 old_chain
= make_cleanup (free_current_contents
, &expr
);
2548 agent
= gen_trace_for_expr (get_frame_pc (fi
), expr
);
2549 make_cleanup_free_agent_expr (agent
);
2553 ax_print (gdb_stdout
, agent
);
2555 /* It would be nice to call ax_reqs here to gather some general info
2556 about the expression, and then print out the result. */
2558 do_cleanups (old_chain
);
2562 /* Parse the given expression, compile it into an agent expression
2563 that does direct evaluation, and display the resulting
2567 agent_eval_command (char *exp
, int from_tty
)
2569 struct cleanup
*old_chain
= 0;
2570 struct expression
*expr
;
2571 struct agent_expr
*agent
;
2572 struct frame_info
*fi
= get_current_frame (); /* need current scope */
2574 /* We don't deal with overlay debugging at the moment. We need to
2575 think more carefully about this. If you copy this code into
2576 another command, change the error message; the user shouldn't
2577 have to know anything about agent expressions. */
2578 if (overlay_debugging
)
2579 error (_("GDB can't do agent expression translation with overlays."));
2582 error_no_arg (_("expression to translate"));
2584 expr
= parse_expression (exp
);
2585 old_chain
= make_cleanup (free_current_contents
, &expr
);
2586 agent
= gen_eval_for_expr (get_frame_pc (fi
), expr
);
2587 make_cleanup_free_agent_expr (agent
);
2589 ax_print (gdb_stdout
, agent
);
2591 /* It would be nice to call ax_reqs here to gather some general info
2592 about the expression, and then print out the result. */
2594 do_cleanups (old_chain
);
2599 /* Initialization code. */
2601 void _initialize_ax_gdb (void);
2603 _initialize_ax_gdb (void)
2605 add_cmd ("agent", class_maintenance
, agent_command
,
2606 _("Translate an expression into "
2607 "remote agent bytecode for tracing."),
2610 add_cmd ("agent-eval", class_maintenance
, agent_eval_command
,
2611 _("Translate an expression into remote "
2612 "agent bytecode for evaluation."),
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