1 /* DWARF 2 Expression Evaluator.
3 Copyright (C) 2001-2003, 2005, 2007-2012 Free Software Foundation,
6 Contributed by Daniel Berlin (dan@dberlin.org)
8 This file is part of GDB.
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>. */
29 #include "dwarf2expr.h"
30 #include "gdb_assert.h"
32 /* Local prototypes. */
34 static void execute_stack_op (struct dwarf_expr_context
*,
35 const gdb_byte
*, const gdb_byte
*);
37 /* Cookie for gdbarch data. */
39 static struct gdbarch_data
*dwarf_arch_cookie
;
41 /* This holds gdbarch-specific types used by the DWARF expression
42 evaluator. See comments in execute_stack_op. */
44 struct dwarf_gdbarch_types
46 struct type
*dw_types
[3];
49 /* Allocate and fill in dwarf_gdbarch_types for an arch. */
52 dwarf_gdbarch_types_init (struct gdbarch
*gdbarch
)
54 struct dwarf_gdbarch_types
*types
55 = GDBARCH_OBSTACK_ZALLOC (gdbarch
, struct dwarf_gdbarch_types
);
57 /* The types themselves are lazily initialized. */
62 /* Return the type used for DWARF operations where the type is
63 unspecified in the DWARF spec. Only certain sizes are
67 dwarf_expr_address_type (struct dwarf_expr_context
*ctx
)
69 struct dwarf_gdbarch_types
*types
= gdbarch_data (ctx
->gdbarch
,
73 if (ctx
->addr_size
== 2)
75 else if (ctx
->addr_size
== 4)
77 else if (ctx
->addr_size
== 8)
80 error (_("Unsupported address size in DWARF expressions: %d bits"),
83 if (types
->dw_types
[ndx
] == NULL
)
85 = arch_integer_type (ctx
->gdbarch
,
87 0, "<signed DWARF address type>");
89 return types
->dw_types
[ndx
];
92 /* Create a new context for the expression evaluator. */
94 struct dwarf_expr_context
*
95 new_dwarf_expr_context (void)
97 struct dwarf_expr_context
*retval
;
99 retval
= xcalloc (1, sizeof (struct dwarf_expr_context
));
100 retval
->stack_len
= 0;
101 retval
->stack_allocated
= 10;
102 retval
->stack
= xmalloc (retval
->stack_allocated
103 * sizeof (struct dwarf_stack_value
));
104 retval
->num_pieces
= 0;
106 retval
->max_recursion_depth
= 0x100;
110 /* Release the memory allocated to CTX. */
113 free_dwarf_expr_context (struct dwarf_expr_context
*ctx
)
120 /* Helper for make_cleanup_free_dwarf_expr_context. */
123 free_dwarf_expr_context_cleanup (void *arg
)
125 free_dwarf_expr_context (arg
);
128 /* Return a cleanup that calls free_dwarf_expr_context. */
131 make_cleanup_free_dwarf_expr_context (struct dwarf_expr_context
*ctx
)
133 return make_cleanup (free_dwarf_expr_context_cleanup
, ctx
);
136 /* Expand the memory allocated to CTX's stack to contain at least
137 NEED more elements than are currently used. */
140 dwarf_expr_grow_stack (struct dwarf_expr_context
*ctx
, size_t need
)
142 if (ctx
->stack_len
+ need
> ctx
->stack_allocated
)
144 size_t newlen
= ctx
->stack_len
+ need
+ 10;
146 ctx
->stack
= xrealloc (ctx
->stack
,
147 newlen
* sizeof (struct dwarf_stack_value
));
148 ctx
->stack_allocated
= newlen
;
152 /* Push VALUE onto CTX's stack. */
155 dwarf_expr_push (struct dwarf_expr_context
*ctx
, struct value
*value
,
158 struct dwarf_stack_value
*v
;
160 dwarf_expr_grow_stack (ctx
, 1);
161 v
= &ctx
->stack
[ctx
->stack_len
++];
163 v
->in_stack_memory
= in_stack_memory
;
166 /* Push VALUE onto CTX's stack. */
169 dwarf_expr_push_address (struct dwarf_expr_context
*ctx
, CORE_ADDR value
,
172 dwarf_expr_push (ctx
,
173 value_from_ulongest (dwarf_expr_address_type (ctx
), value
),
177 /* Pop the top item off of CTX's stack. */
180 dwarf_expr_pop (struct dwarf_expr_context
*ctx
)
182 if (ctx
->stack_len
<= 0)
183 error (_("dwarf expression stack underflow"));
187 /* Retrieve the N'th item on CTX's stack. */
190 dwarf_expr_fetch (struct dwarf_expr_context
*ctx
, int n
)
192 if (ctx
->stack_len
<= n
)
193 error (_("Asked for position %d of stack, "
194 "stack only has %d elements on it."),
196 return ctx
->stack
[ctx
->stack_len
- (1 + n
)].value
;
199 /* Require that TYPE be an integral type; throw an exception if not. */
202 dwarf_require_integral (struct type
*type
)
204 if (TYPE_CODE (type
) != TYPE_CODE_INT
205 && TYPE_CODE (type
) != TYPE_CODE_CHAR
206 && TYPE_CODE (type
) != TYPE_CODE_BOOL
)
207 error (_("integral type expected in DWARF expression"));
210 /* Return the unsigned form of TYPE. TYPE is necessarily an integral
214 get_unsigned_type (struct gdbarch
*gdbarch
, struct type
*type
)
216 switch (TYPE_LENGTH (type
))
219 return builtin_type (gdbarch
)->builtin_uint8
;
221 return builtin_type (gdbarch
)->builtin_uint16
;
223 return builtin_type (gdbarch
)->builtin_uint32
;
225 return builtin_type (gdbarch
)->builtin_uint64
;
227 error (_("no unsigned variant found for type, while evaluating "
228 "DWARF expression"));
232 /* Return the signed form of TYPE. TYPE is necessarily an integral
236 get_signed_type (struct gdbarch
*gdbarch
, struct type
*type
)
238 switch (TYPE_LENGTH (type
))
241 return builtin_type (gdbarch
)->builtin_int8
;
243 return builtin_type (gdbarch
)->builtin_int16
;
245 return builtin_type (gdbarch
)->builtin_int32
;
247 return builtin_type (gdbarch
)->builtin_int64
;
249 error (_("no signed variant found for type, while evaluating "
250 "DWARF expression"));
254 /* Retrieve the N'th item on CTX's stack, converted to an address. */
257 dwarf_expr_fetch_address (struct dwarf_expr_context
*ctx
, int n
)
259 struct value
*result_val
= dwarf_expr_fetch (ctx
, n
);
260 enum bfd_endian byte_order
= gdbarch_byte_order (ctx
->gdbarch
);
263 dwarf_require_integral (value_type (result_val
));
264 result
= extract_unsigned_integer (value_contents (result_val
),
265 TYPE_LENGTH (value_type (result_val
)),
268 /* For most architectures, calling extract_unsigned_integer() alone
269 is sufficient for extracting an address. However, some
270 architectures (e.g. MIPS) use signed addresses and using
271 extract_unsigned_integer() will not produce a correct
272 result. Make sure we invoke gdbarch_integer_to_address()
273 for those architectures which require it. */
274 if (gdbarch_integer_to_address_p (ctx
->gdbarch
))
276 gdb_byte
*buf
= alloca (ctx
->addr_size
);
277 struct type
*int_type
= get_unsigned_type (ctx
->gdbarch
,
278 value_type (result_val
));
280 store_unsigned_integer (buf
, ctx
->addr_size
, byte_order
, result
);
281 return gdbarch_integer_to_address (ctx
->gdbarch
, int_type
, buf
);
284 return (CORE_ADDR
) result
;
287 /* Retrieve the in_stack_memory flag of the N'th item on CTX's stack. */
290 dwarf_expr_fetch_in_stack_memory (struct dwarf_expr_context
*ctx
, int n
)
292 if (ctx
->stack_len
<= n
)
293 error (_("Asked for position %d of stack, "
294 "stack only has %d elements on it."),
296 return ctx
->stack
[ctx
->stack_len
- (1 + n
)].in_stack_memory
;
299 /* Return true if the expression stack is empty. */
302 dwarf_expr_stack_empty_p (struct dwarf_expr_context
*ctx
)
304 return ctx
->stack_len
== 0;
307 /* Add a new piece to CTX's piece list. */
309 add_piece (struct dwarf_expr_context
*ctx
, ULONGEST size
, ULONGEST offset
)
311 struct dwarf_expr_piece
*p
;
315 ctx
->pieces
= xrealloc (ctx
->pieces
,
317 * sizeof (struct dwarf_expr_piece
)));
319 p
= &ctx
->pieces
[ctx
->num_pieces
- 1];
320 p
->location
= ctx
->location
;
324 if (p
->location
== DWARF_VALUE_LITERAL
)
326 p
->v
.literal
.data
= ctx
->data
;
327 p
->v
.literal
.length
= ctx
->len
;
329 else if (dwarf_expr_stack_empty_p (ctx
))
331 p
->location
= DWARF_VALUE_OPTIMIZED_OUT
;
332 /* Also reset the context's location, for our callers. This is
333 a somewhat strange approach, but this lets us avoid setting
334 the location to DWARF_VALUE_MEMORY in all the individual
335 cases in the evaluator. */
336 ctx
->location
= DWARF_VALUE_OPTIMIZED_OUT
;
338 else if (p
->location
== DWARF_VALUE_MEMORY
)
340 p
->v
.mem
.addr
= dwarf_expr_fetch_address (ctx
, 0);
341 p
->v
.mem
.in_stack_memory
= dwarf_expr_fetch_in_stack_memory (ctx
, 0);
343 else if (p
->location
== DWARF_VALUE_IMPLICIT_POINTER
)
345 p
->v
.ptr
.die
= ctx
->len
;
346 p
->v
.ptr
.offset
= value_as_long (dwarf_expr_fetch (ctx
, 0));
348 else if (p
->location
== DWARF_VALUE_REGISTER
)
349 p
->v
.regno
= value_as_long (dwarf_expr_fetch (ctx
, 0));
352 p
->v
.value
= dwarf_expr_fetch (ctx
, 0);
356 /* Evaluate the expression at ADDR (LEN bytes long) using the context
360 dwarf_expr_eval (struct dwarf_expr_context
*ctx
, const gdb_byte
*addr
,
363 int old_recursion_depth
= ctx
->recursion_depth
;
365 execute_stack_op (ctx
, addr
, addr
+ len
);
367 /* CTX RECURSION_DEPTH becomes invalid if an exception was thrown here. */
369 gdb_assert (ctx
->recursion_depth
== old_recursion_depth
);
372 /* Decode the unsigned LEB128 constant at BUF into the variable pointed to
373 by R, and return the new value of BUF. Verify that it doesn't extend
374 past BUF_END. R can be NULL, the constant is then only skipped. */
377 read_uleb128 (const gdb_byte
*buf
, const gdb_byte
*buf_end
, ULONGEST
* r
)
386 error (_("read_uleb128: Corrupted DWARF expression."));
389 result
|= ((ULONGEST
) (byte
& 0x7f)) << shift
;
390 if ((byte
& 0x80) == 0)
399 /* Decode the signed LEB128 constant at BUF into the variable pointed to
400 by R, and return the new value of BUF. Verify that it doesn't extend
401 past BUF_END. R can be NULL, the constant is then only skipped. */
404 read_sleb128 (const gdb_byte
*buf
, const gdb_byte
*buf_end
, LONGEST
* r
)
413 error (_("read_sleb128: Corrupted DWARF expression."));
416 result
|= ((ULONGEST
) (byte
& 0x7f)) << shift
;
418 if ((byte
& 0x80) == 0)
421 if (shift
< (sizeof (*r
) * 8) && (byte
& 0x40) != 0)
422 result
|= -(((LONGEST
) 1) << shift
);
430 /* Check that the current operator is either at the end of an
431 expression, or that it is followed by a composition operator. */
434 dwarf_expr_require_composition (const gdb_byte
*op_ptr
, const gdb_byte
*op_end
,
437 /* It seems like DW_OP_GNU_uninit should be handled here. However,
438 it doesn't seem to make sense for DW_OP_*_value, and it was not
439 checked at the other place that this function is called. */
440 if (op_ptr
!= op_end
&& *op_ptr
!= DW_OP_piece
&& *op_ptr
!= DW_OP_bit_piece
)
441 error (_("DWARF-2 expression error: `%s' operations must be "
442 "used either alone or in conjunction with DW_OP_piece "
443 "or DW_OP_bit_piece."),
447 /* Return true iff the types T1 and T2 are "the same". This only does
448 checks that might reasonably be needed to compare DWARF base
452 base_types_equal_p (struct type
*t1
, struct type
*t2
)
454 if (TYPE_CODE (t1
) != TYPE_CODE (t2
))
456 if (TYPE_UNSIGNED (t1
) != TYPE_UNSIGNED (t2
))
458 return TYPE_LENGTH (t1
) == TYPE_LENGTH (t2
);
461 /* A convenience function to call get_base_type on CTX and return the
462 result. DIE is the DIE whose type we need. SIZE is non-zero if
463 this function should verify that the resulting type has the correct
467 dwarf_get_base_type (struct dwarf_expr_context
*ctx
, ULONGEST die
, int size
)
471 if (ctx
->funcs
->get_base_type
)
473 result
= ctx
->funcs
->get_base_type (ctx
, die
);
475 error (_("Could not find type for DW_OP_GNU_const_type"));
476 if (size
!= 0 && TYPE_LENGTH (result
) != size
)
477 error (_("DW_OP_GNU_const_type has different sizes for type and data"));
480 /* Anything will do. */
481 result
= builtin_type (ctx
->gdbarch
)->builtin_int
;
486 /* If <BUF..BUF_END] contains DW_FORM_block* with single DW_OP_reg* return the
487 DWARF register number. Otherwise return -1. */
490 dwarf_block_to_dwarf_reg (const gdb_byte
*buf
, const gdb_byte
*buf_end
)
496 if (*buf
>= DW_OP_reg0
&& *buf
<= DW_OP_reg31
)
498 if (buf_end
- buf
!= 1)
500 return *buf
- DW_OP_reg0
;
503 if (*buf
== DW_OP_GNU_regval_type
)
506 buf
= read_uleb128 (buf
, buf_end
, &dwarf_reg
);
507 buf
= read_uleb128 (buf
, buf_end
, NULL
);
509 else if (*buf
== DW_OP_regx
)
512 buf
= read_uleb128 (buf
, buf_end
, &dwarf_reg
);
516 if (buf
!= buf_end
|| (int) dwarf_reg
!= dwarf_reg
)
521 /* If <BUF..BUF_END] contains DW_FORM_block* with just DW_OP_breg*(0) and
522 DW_OP_deref* return the DWARF register number. Otherwise return -1.
523 DEREF_SIZE_RETURN contains -1 for DW_OP_deref; otherwise it contains the
524 size from DW_OP_deref_size. */
527 dwarf_block_to_dwarf_reg_deref (const gdb_byte
*buf
, const gdb_byte
*buf_end
,
528 CORE_ADDR
*deref_size_return
)
535 if (*buf
>= DW_OP_breg0
&& *buf
<= DW_OP_breg31
)
537 dwarf_reg
= *buf
- DW_OP_breg0
;
540 else if (*buf
== DW_OP_bregx
)
543 buf
= read_uleb128 (buf
, buf_end
, &dwarf_reg
);
544 if ((int) dwarf_reg
!= dwarf_reg
)
550 buf
= read_sleb128 (buf
, buf_end
, &offset
);
557 if (*buf
== DW_OP_deref
)
560 *deref_size_return
= -1;
562 else if (*buf
== DW_OP_deref_size
)
567 *deref_size_return
= *buf
++;
578 /* If <BUF..BUF_END] contains DW_FORM_block* with single DW_OP_fbreg(X) fill
579 in FB_OFFSET_RETURN with the X offset and return 1. Otherwise return 0. */
582 dwarf_block_to_fb_offset (const gdb_byte
*buf
, const gdb_byte
*buf_end
,
583 CORE_ADDR
*fb_offset_return
)
590 if (*buf
!= DW_OP_fbreg
)
594 buf
= read_sleb128 (buf
, buf_end
, &fb_offset
);
595 *fb_offset_return
= fb_offset
;
596 if (buf
!= buf_end
|| fb_offset
!= (LONGEST
) *fb_offset_return
)
602 /* If <BUF..BUF_END] contains DW_FORM_block* with single DW_OP_bregSP(X) fill
603 in SP_OFFSET_RETURN with the X offset and return 1. Otherwise return 0.
604 The matched SP register number depends on GDBARCH. */
607 dwarf_block_to_sp_offset (struct gdbarch
*gdbarch
, const gdb_byte
*buf
,
608 const gdb_byte
*buf_end
, CORE_ADDR
*sp_offset_return
)
615 if (*buf
>= DW_OP_breg0
&& *buf
<= DW_OP_breg31
)
617 dwarf_reg
= *buf
- DW_OP_breg0
;
622 if (*buf
!= DW_OP_bregx
)
625 buf
= read_uleb128 (buf
, buf_end
, &dwarf_reg
);
628 if (gdbarch_dwarf2_reg_to_regnum (gdbarch
, dwarf_reg
)
629 != gdbarch_sp_regnum (gdbarch
))
632 buf
= read_sleb128 (buf
, buf_end
, &sp_offset
);
633 *sp_offset_return
= sp_offset
;
634 if (buf
!= buf_end
|| sp_offset
!= (LONGEST
) *sp_offset_return
)
640 /* The engine for the expression evaluator. Using the context in CTX,
641 evaluate the expression between OP_PTR and OP_END. */
644 execute_stack_op (struct dwarf_expr_context
*ctx
,
645 const gdb_byte
*op_ptr
, const gdb_byte
*op_end
)
647 enum bfd_endian byte_order
= gdbarch_byte_order (ctx
->gdbarch
);
648 /* Old-style "untyped" DWARF values need special treatment in a
649 couple of places, specifically DW_OP_mod and DW_OP_shr. We need
650 a special type for these values so we can distinguish them from
651 values that have an explicit type, because explicitly-typed
652 values do not need special treatment. This special type must be
653 different (in the `==' sense) from any base type coming from the
655 struct type
*address_type
= dwarf_expr_address_type (ctx
);
657 ctx
->location
= DWARF_VALUE_MEMORY
;
658 ctx
->initialized
= 1; /* Default is initialized. */
660 if (ctx
->recursion_depth
> ctx
->max_recursion_depth
)
661 error (_("DWARF-2 expression error: Loop detected (%d)."),
662 ctx
->recursion_depth
);
663 ctx
->recursion_depth
++;
665 while (op_ptr
< op_end
)
667 enum dwarf_location_atom op
= *op_ptr
++;
669 /* Assume the value is not in stack memory.
670 Code that knows otherwise sets this to 1.
671 Some arithmetic on stack addresses can probably be assumed to still
672 be a stack address, but we skip this complication for now.
673 This is just an optimization, so it's always ok to punt
674 and leave this as 0. */
675 int in_stack_memory
= 0;
676 ULONGEST uoffset
, reg
;
678 struct value
*result_val
= NULL
;
680 /* The DWARF expression might have a bug causing an infinite
681 loop. In that case, quitting is the only way out. */
718 result
= op
- DW_OP_lit0
;
719 result_val
= value_from_ulongest (address_type
, result
);
723 result
= extract_unsigned_integer (op_ptr
,
724 ctx
->addr_size
, byte_order
);
725 op_ptr
+= ctx
->addr_size
;
726 /* Some versions of GCC emit DW_OP_addr before
727 DW_OP_GNU_push_tls_address. In this case the value is an
728 index, not an address. We don't support things like
729 branching between the address and the TLS op. */
730 if (op_ptr
>= op_end
|| *op_ptr
!= DW_OP_GNU_push_tls_address
)
731 result
+= ctx
->offset
;
732 result_val
= value_from_ulongest (address_type
, result
);
736 result
= extract_unsigned_integer (op_ptr
, 1, byte_order
);
737 result_val
= value_from_ulongest (address_type
, result
);
741 result
= extract_signed_integer (op_ptr
, 1, byte_order
);
742 result_val
= value_from_ulongest (address_type
, result
);
746 result
= extract_unsigned_integer (op_ptr
, 2, byte_order
);
747 result_val
= value_from_ulongest (address_type
, result
);
751 result
= extract_signed_integer (op_ptr
, 2, byte_order
);
752 result_val
= value_from_ulongest (address_type
, result
);
756 result
= extract_unsigned_integer (op_ptr
, 4, byte_order
);
757 result_val
= value_from_ulongest (address_type
, result
);
761 result
= extract_signed_integer (op_ptr
, 4, byte_order
);
762 result_val
= value_from_ulongest (address_type
, result
);
766 result
= extract_unsigned_integer (op_ptr
, 8, byte_order
);
767 result_val
= value_from_ulongest (address_type
, result
);
771 result
= extract_signed_integer (op_ptr
, 8, byte_order
);
772 result_val
= value_from_ulongest (address_type
, result
);
776 op_ptr
= read_uleb128 (op_ptr
, op_end
, &uoffset
);
778 result_val
= value_from_ulongest (address_type
, result
);
781 op_ptr
= read_sleb128 (op_ptr
, op_end
, &offset
);
783 result_val
= value_from_ulongest (address_type
, result
);
786 /* The DW_OP_reg operations are required to occur alone in
787 location expressions. */
821 && *op_ptr
!= DW_OP_piece
822 && *op_ptr
!= DW_OP_bit_piece
823 && *op_ptr
!= DW_OP_GNU_uninit
)
824 error (_("DWARF-2 expression error: DW_OP_reg operations must be "
825 "used either alone or in conjunction with DW_OP_piece "
826 "or DW_OP_bit_piece."));
828 result
= op
- DW_OP_reg0
;
829 result_val
= value_from_ulongest (address_type
, result
);
830 ctx
->location
= DWARF_VALUE_REGISTER
;
834 op_ptr
= read_uleb128 (op_ptr
, op_end
, ®
);
835 dwarf_expr_require_composition (op_ptr
, op_end
, "DW_OP_regx");
838 result_val
= value_from_ulongest (address_type
, result
);
839 ctx
->location
= DWARF_VALUE_REGISTER
;
842 case DW_OP_implicit_value
:
846 op_ptr
= read_uleb128 (op_ptr
, op_end
, &len
);
847 if (op_ptr
+ len
> op_end
)
848 error (_("DW_OP_implicit_value: too few bytes available."));
851 ctx
->location
= DWARF_VALUE_LITERAL
;
853 dwarf_expr_require_composition (op_ptr
, op_end
,
854 "DW_OP_implicit_value");
858 case DW_OP_stack_value
:
859 ctx
->location
= DWARF_VALUE_STACK
;
860 dwarf_expr_require_composition (op_ptr
, op_end
, "DW_OP_stack_value");
863 case DW_OP_GNU_implicit_pointer
:
868 if (ctx
->ref_addr_size
== -1)
869 error (_("DWARF-2 expression error: DW_OP_GNU_implicit_pointer "
870 "is not allowed in frame context"));
872 /* The referred-to DIE. */
873 ctx
->len
= extract_unsigned_integer (op_ptr
, ctx
->ref_addr_size
,
875 op_ptr
+= ctx
->ref_addr_size
;
877 /* The byte offset into the data. */
878 op_ptr
= read_sleb128 (op_ptr
, op_end
, &len
);
879 result
= (ULONGEST
) len
;
880 result_val
= value_from_ulongest (address_type
, result
);
882 ctx
->location
= DWARF_VALUE_IMPLICIT_POINTER
;
883 dwarf_expr_require_composition (op_ptr
, op_end
,
884 "DW_OP_GNU_implicit_pointer");
921 op_ptr
= read_sleb128 (op_ptr
, op_end
, &offset
);
922 result
= (ctx
->funcs
->read_reg
) (ctx
->baton
, op
- DW_OP_breg0
);
924 result_val
= value_from_ulongest (address_type
, result
);
929 op_ptr
= read_uleb128 (op_ptr
, op_end
, ®
);
930 op_ptr
= read_sleb128 (op_ptr
, op_end
, &offset
);
931 result
= (ctx
->funcs
->read_reg
) (ctx
->baton
, reg
);
933 result_val
= value_from_ulongest (address_type
, result
);
938 const gdb_byte
*datastart
;
940 unsigned int before_stack_len
;
942 op_ptr
= read_sleb128 (op_ptr
, op_end
, &offset
);
943 /* Rather than create a whole new context, we simply
944 record the stack length before execution, then reset it
945 afterwards, effectively erasing whatever the recursive
947 before_stack_len
= ctx
->stack_len
;
948 /* FIXME: cagney/2003-03-26: This code should be using
949 get_frame_base_address(), and then implement a dwarf2
950 specific this_base method. */
951 (ctx
->funcs
->get_frame_base
) (ctx
->baton
, &datastart
, &datalen
);
952 dwarf_expr_eval (ctx
, datastart
, datalen
);
953 if (ctx
->location
== DWARF_VALUE_MEMORY
)
954 result
= dwarf_expr_fetch_address (ctx
, 0);
955 else if (ctx
->location
== DWARF_VALUE_REGISTER
)
956 result
= (ctx
->funcs
->read_reg
) (ctx
->baton
,
957 value_as_long (dwarf_expr_fetch (ctx
, 0)));
959 error (_("Not implemented: computing frame "
960 "base using explicit value operator"));
961 result
= result
+ offset
;
962 result_val
= value_from_ulongest (address_type
, result
);
964 ctx
->stack_len
= before_stack_len
;
965 ctx
->location
= DWARF_VALUE_MEMORY
;
970 result_val
= dwarf_expr_fetch (ctx
, 0);
971 in_stack_memory
= dwarf_expr_fetch_in_stack_memory (ctx
, 0);
975 dwarf_expr_pop (ctx
);
980 result_val
= dwarf_expr_fetch (ctx
, offset
);
981 in_stack_memory
= dwarf_expr_fetch_in_stack_memory (ctx
, offset
);
986 struct dwarf_stack_value t1
, t2
;
988 if (ctx
->stack_len
< 2)
989 error (_("Not enough elements for "
990 "DW_OP_swap. Need 2, have %d."),
992 t1
= ctx
->stack
[ctx
->stack_len
- 1];
993 t2
= ctx
->stack
[ctx
->stack_len
- 2];
994 ctx
->stack
[ctx
->stack_len
- 1] = t2
;
995 ctx
->stack
[ctx
->stack_len
- 2] = t1
;
1000 result_val
= dwarf_expr_fetch (ctx
, 1);
1001 in_stack_memory
= dwarf_expr_fetch_in_stack_memory (ctx
, 1);
1006 struct dwarf_stack_value t1
, t2
, t3
;
1008 if (ctx
->stack_len
< 3)
1009 error (_("Not enough elements for "
1010 "DW_OP_rot. Need 3, have %d."),
1012 t1
= ctx
->stack
[ctx
->stack_len
- 1];
1013 t2
= ctx
->stack
[ctx
->stack_len
- 2];
1014 t3
= ctx
->stack
[ctx
->stack_len
- 3];
1015 ctx
->stack
[ctx
->stack_len
- 1] = t2
;
1016 ctx
->stack
[ctx
->stack_len
- 2] = t3
;
1017 ctx
->stack
[ctx
->stack_len
- 3] = t1
;
1022 case DW_OP_deref_size
:
1023 case DW_OP_GNU_deref_type
:
1025 int addr_size
= (op
== DW_OP_deref
? ctx
->addr_size
: *op_ptr
++);
1026 gdb_byte
*buf
= alloca (addr_size
);
1027 CORE_ADDR addr
= dwarf_expr_fetch_address (ctx
, 0);
1030 dwarf_expr_pop (ctx
);
1032 if (op
== DW_OP_GNU_deref_type
)
1036 op_ptr
= read_uleb128 (op_ptr
, op_end
, &type_die
);
1037 type
= dwarf_get_base_type (ctx
, type_die
, 0);
1040 type
= address_type
;
1042 (ctx
->funcs
->read_mem
) (ctx
->baton
, buf
, addr
, addr_size
);
1044 /* If the size of the object read from memory is different
1045 from the type length, we need to zero-extend it. */
1046 if (TYPE_LENGTH (type
) != addr_size
)
1049 extract_unsigned_integer (buf
, addr_size
, byte_order
);
1051 buf
= alloca (TYPE_LENGTH (type
));
1052 store_unsigned_integer (buf
, TYPE_LENGTH (type
),
1053 byte_order
, result
);
1056 result_val
= value_from_contents_and_address (type
, buf
, addr
);
1063 case DW_OP_plus_uconst
:
1065 /* Unary operations. */
1066 result_val
= dwarf_expr_fetch (ctx
, 0);
1067 dwarf_expr_pop (ctx
);
1072 if (value_less (result_val
,
1073 value_zero (value_type (result_val
), not_lval
)))
1074 result_val
= value_neg (result_val
);
1077 result_val
= value_neg (result_val
);
1080 dwarf_require_integral (value_type (result_val
));
1081 result_val
= value_complement (result_val
);
1083 case DW_OP_plus_uconst
:
1084 dwarf_require_integral (value_type (result_val
));
1085 result
= value_as_long (result_val
);
1086 op_ptr
= read_uleb128 (op_ptr
, op_end
, ®
);
1088 result_val
= value_from_ulongest (address_type
, result
);
1112 /* Binary operations. */
1113 struct value
*first
, *second
;
1115 second
= dwarf_expr_fetch (ctx
, 0);
1116 dwarf_expr_pop (ctx
);
1118 first
= dwarf_expr_fetch (ctx
, 0);
1119 dwarf_expr_pop (ctx
);
1121 if (! base_types_equal_p (value_type (first
), value_type (second
)))
1122 error (_("Incompatible types on DWARF stack"));
1127 dwarf_require_integral (value_type (first
));
1128 dwarf_require_integral (value_type (second
));
1129 result_val
= value_binop (first
, second
, BINOP_BITWISE_AND
);
1132 result_val
= value_binop (first
, second
, BINOP_DIV
);
1135 result_val
= value_binop (first
, second
, BINOP_SUB
);
1140 struct type
*orig_type
= value_type (first
);
1142 /* We have to special-case "old-style" untyped values
1143 -- these must have mod computed using unsigned
1145 if (orig_type
== address_type
)
1148 = get_unsigned_type (ctx
->gdbarch
, orig_type
);
1151 first
= value_cast (utype
, first
);
1152 second
= value_cast (utype
, second
);
1154 /* Note that value_binop doesn't handle float or
1155 decimal float here. This seems unimportant. */
1156 result_val
= value_binop (first
, second
, BINOP_MOD
);
1158 result_val
= value_cast (orig_type
, result_val
);
1162 result_val
= value_binop (first
, second
, BINOP_MUL
);
1165 dwarf_require_integral (value_type (first
));
1166 dwarf_require_integral (value_type (second
));
1167 result_val
= value_binop (first
, second
, BINOP_BITWISE_IOR
);
1170 result_val
= value_binop (first
, second
, BINOP_ADD
);
1173 dwarf_require_integral (value_type (first
));
1174 dwarf_require_integral (value_type (second
));
1175 result_val
= value_binop (first
, second
, BINOP_LSH
);
1178 dwarf_require_integral (value_type (first
));
1179 dwarf_require_integral (value_type (second
));
1180 if (!TYPE_UNSIGNED (value_type (first
)))
1183 = get_unsigned_type (ctx
->gdbarch
, value_type (first
));
1185 first
= value_cast (utype
, first
);
1188 result_val
= value_binop (first
, second
, BINOP_RSH
);
1189 /* Make sure we wind up with the same type we started
1191 if (value_type (result_val
) != value_type (second
))
1192 result_val
= value_cast (value_type (second
), result_val
);
1195 dwarf_require_integral (value_type (first
));
1196 dwarf_require_integral (value_type (second
));
1197 if (TYPE_UNSIGNED (value_type (first
)))
1200 = get_signed_type (ctx
->gdbarch
, value_type (first
));
1202 first
= value_cast (stype
, first
);
1205 result_val
= value_binop (first
, second
, BINOP_RSH
);
1206 /* Make sure we wind up with the same type we started
1208 if (value_type (result_val
) != value_type (second
))
1209 result_val
= value_cast (value_type (second
), result_val
);
1212 dwarf_require_integral (value_type (first
));
1213 dwarf_require_integral (value_type (second
));
1214 result_val
= value_binop (first
, second
, BINOP_BITWISE_XOR
);
1217 /* A <= B is !(B < A). */
1218 result
= ! value_less (second
, first
);
1219 result_val
= value_from_ulongest (address_type
, result
);
1222 /* A >= B is !(A < B). */
1223 result
= ! value_less (first
, second
);
1224 result_val
= value_from_ulongest (address_type
, result
);
1227 result
= value_equal (first
, second
);
1228 result_val
= value_from_ulongest (address_type
, result
);
1231 result
= value_less (first
, second
);
1232 result_val
= value_from_ulongest (address_type
, result
);
1235 /* A > B is B < A. */
1236 result
= value_less (second
, first
);
1237 result_val
= value_from_ulongest (address_type
, result
);
1240 result
= ! value_equal (first
, second
);
1241 result_val
= value_from_ulongest (address_type
, result
);
1244 internal_error (__FILE__
, __LINE__
,
1245 _("Can't be reached."));
1250 case DW_OP_call_frame_cfa
:
1251 result
= (ctx
->funcs
->get_frame_cfa
) (ctx
->baton
);
1252 result_val
= value_from_ulongest (address_type
, result
);
1253 in_stack_memory
= 1;
1256 case DW_OP_GNU_push_tls_address
:
1257 /* Variable is at a constant offset in the thread-local
1258 storage block into the objfile for the current thread and
1259 the dynamic linker module containing this expression. Here
1260 we return returns the offset from that base. The top of the
1261 stack has the offset from the beginning of the thread
1262 control block at which the variable is located. Nothing
1263 should follow this operator, so the top of stack would be
1265 result
= value_as_long (dwarf_expr_fetch (ctx
, 0));
1266 dwarf_expr_pop (ctx
);
1267 result
= (ctx
->funcs
->get_tls_address
) (ctx
->baton
, result
);
1268 result_val
= value_from_ulongest (address_type
, result
);
1272 offset
= extract_signed_integer (op_ptr
, 2, byte_order
);
1281 offset
= extract_signed_integer (op_ptr
, 2, byte_order
);
1283 val
= dwarf_expr_fetch (ctx
, 0);
1284 dwarf_require_integral (value_type (val
));
1285 if (value_as_long (val
) != 0)
1287 dwarf_expr_pop (ctx
);
1298 /* Record the piece. */
1299 op_ptr
= read_uleb128 (op_ptr
, op_end
, &size
);
1300 add_piece (ctx
, 8 * size
, 0);
1302 /* Pop off the address/regnum, and reset the location
1304 if (ctx
->location
!= DWARF_VALUE_LITERAL
1305 && ctx
->location
!= DWARF_VALUE_OPTIMIZED_OUT
)
1306 dwarf_expr_pop (ctx
);
1307 ctx
->location
= DWARF_VALUE_MEMORY
;
1311 case DW_OP_bit_piece
:
1313 ULONGEST size
, offset
;
1315 /* Record the piece. */
1316 op_ptr
= read_uleb128 (op_ptr
, op_end
, &size
);
1317 op_ptr
= read_uleb128 (op_ptr
, op_end
, &offset
);
1318 add_piece (ctx
, size
, offset
);
1320 /* Pop off the address/regnum, and reset the location
1322 if (ctx
->location
!= DWARF_VALUE_LITERAL
1323 && ctx
->location
!= DWARF_VALUE_OPTIMIZED_OUT
)
1324 dwarf_expr_pop (ctx
);
1325 ctx
->location
= DWARF_VALUE_MEMORY
;
1329 case DW_OP_GNU_uninit
:
1330 if (op_ptr
!= op_end
)
1331 error (_("DWARF-2 expression error: DW_OP_GNU_uninit must always "
1332 "be the very last op."));
1334 ctx
->initialized
= 0;
1338 result
= extract_unsigned_integer (op_ptr
, 2, byte_order
);
1340 ctx
->funcs
->dwarf_call (ctx
, result
);
1344 result
= extract_unsigned_integer (op_ptr
, 4, byte_order
);
1346 ctx
->funcs
->dwarf_call (ctx
, result
);
1349 case DW_OP_GNU_entry_value
:
1353 CORE_ADDR deref_size
;
1355 op_ptr
= read_uleb128 (op_ptr
, op_end
, &len
);
1356 if (op_ptr
+ len
> op_end
)
1357 error (_("DW_OP_GNU_entry_value: too few bytes available."));
1359 dwarf_reg
= dwarf_block_to_dwarf_reg (op_ptr
, op_ptr
+ len
);
1360 if (dwarf_reg
!= -1)
1363 ctx
->funcs
->push_dwarf_reg_entry_value (ctx
, dwarf_reg
,
1365 -1 /* deref_size */);
1369 dwarf_reg
= dwarf_block_to_dwarf_reg_deref (op_ptr
, op_ptr
+ len
,
1371 if (dwarf_reg
!= -1)
1373 if (deref_size
== -1)
1374 deref_size
= ctx
->addr_size
;
1376 ctx
->funcs
->push_dwarf_reg_entry_value (ctx
, dwarf_reg
,
1382 error (_("DWARF-2 expression error: DW_OP_GNU_entry_value is "
1383 "supported only for single DW_OP_reg* "
1384 "or for DW_OP_breg*(0)+DW_OP_deref*"));
1387 case DW_OP_GNU_const_type
:
1391 const gdb_byte
*data
;
1394 op_ptr
= read_uleb128 (op_ptr
, op_end
, &type_die
);
1399 type
= dwarf_get_base_type (ctx
, type_die
, n
);
1400 result_val
= value_from_contents (type
, data
);
1404 case DW_OP_GNU_regval_type
:
1409 op_ptr
= read_uleb128 (op_ptr
, op_end
, ®
);
1410 op_ptr
= read_uleb128 (op_ptr
, op_end
, &type_die
);
1412 type
= dwarf_get_base_type (ctx
, type_die
, 0);
1413 result
= (ctx
->funcs
->read_reg
) (ctx
->baton
, reg
);
1414 result_val
= value_from_ulongest (address_type
, result
);
1415 result_val
= value_from_contents (type
,
1416 value_contents_all (result_val
));
1420 case DW_OP_GNU_convert
:
1421 case DW_OP_GNU_reinterpret
:
1426 op_ptr
= read_uleb128 (op_ptr
, op_end
, &type_die
);
1429 type
= address_type
;
1431 type
= dwarf_get_base_type (ctx
, type_die
, 0);
1433 result_val
= dwarf_expr_fetch (ctx
, 0);
1434 dwarf_expr_pop (ctx
);
1436 if (op
== DW_OP_GNU_convert
)
1437 result_val
= value_cast (type
, result_val
);
1438 else if (type
== value_type (result_val
))
1442 else if (TYPE_LENGTH (type
)
1443 != TYPE_LENGTH (value_type (result_val
)))
1444 error (_("DW_OP_GNU_reinterpret has wrong size"));
1447 = value_from_contents (type
,
1448 value_contents_all (result_val
));
1453 error (_("Unhandled dwarf expression opcode 0x%x"), op
);
1456 /* Most things push a result value. */
1457 gdb_assert (result_val
!= NULL
);
1458 dwarf_expr_push (ctx
, result_val
, in_stack_memory
);
1463 /* To simplify our main caller, if the result is an implicit
1464 pointer, then make a pieced value. This is ok because we can't
1465 have implicit pointers in contexts where pieces are invalid. */
1466 if (ctx
->location
== DWARF_VALUE_IMPLICIT_POINTER
)
1467 add_piece (ctx
, 8 * ctx
->addr_size
, 0);
1470 ctx
->recursion_depth
--;
1471 gdb_assert (ctx
->recursion_depth
>= 0);
1474 /* Stub dwarf_expr_context_funcs.get_frame_base implementation. */
1477 ctx_no_get_frame_base (void *baton
, const gdb_byte
**start
, size_t *length
)
1479 error (_("%s is invalid in this context"), "DW_OP_fbreg");
1482 /* Stub dwarf_expr_context_funcs.get_frame_cfa implementation. */
1485 ctx_no_get_frame_cfa (void *baton
)
1487 error (_("%s is invalid in this context"), "DW_OP_call_frame_cfa");
1490 /* Stub dwarf_expr_context_funcs.get_frame_pc implementation. */
1493 ctx_no_get_frame_pc (void *baton
)
1495 error (_("%s is invalid in this context"), "DW_OP_GNU_implicit_pointer");
1498 /* Stub dwarf_expr_context_funcs.get_tls_address implementation. */
1501 ctx_no_get_tls_address (void *baton
, CORE_ADDR offset
)
1503 error (_("%s is invalid in this context"), "DW_OP_GNU_push_tls_address");
1506 /* Stub dwarf_expr_context_funcs.dwarf_call implementation. */
1509 ctx_no_dwarf_call (struct dwarf_expr_context
*ctx
, size_t die_offset
)
1511 error (_("%s is invalid in this context"), "DW_OP_call*");
1514 /* Stub dwarf_expr_context_funcs.get_base_type implementation. */
1517 ctx_no_get_base_type (struct dwarf_expr_context
*ctx
, size_t die
)
1519 error (_("Support for typed DWARF is not supported in this context"));
1522 /* Stub dwarf_expr_context_funcs.push_dwarf_block_entry_value
1526 ctx_no_push_dwarf_reg_entry_value (struct dwarf_expr_context
*ctx
,
1527 int dwarf_reg
, CORE_ADDR fb_offset
,
1530 internal_error (__FILE__
, __LINE__
,
1531 _("Support for DW_OP_GNU_entry_value is unimplemented"));
1535 _initialize_dwarf2expr (void)
1538 = gdbarch_data_register_post_init (dwarf_gdbarch_types_init
);