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bc10db8eb8
Local variables are allocated in the stack and the location list
should look like base register(s) and an offset. Extend the
die_find_variable_by_reg() to handle the following expressions
* DW_OP_breg{0..31}
* DW_OP_bregx
* DW_OP_fbreg
Ususally DWARF subprogram entries have frame base information and
use it to locate stack variable like below:
<2><43d1575>: Abbrev Number: 62 (DW_TAG_variable)
<43d1576> DW_AT_location : 2 byte block: 91 7c (DW_OP_fbreg: -4) <--- here
<43d1579> DW_AT_name : (indirect string, offset: 0x2c00c9): i
<43d157d> DW_AT_decl_file : 1
<43d157e> DW_AT_decl_line : 78
<43d157f> DW_AT_type : <0x43d19d7>
I found some differences on saving the frame base between gcc and clang.
The gcc uses the CFA to get the base so it needs to check the current
frame's CFI info. In this case, stack offset needs to be adjusted from
the start of the CFA.
<1><1bb8d>: Abbrev Number: 102 (DW_TAG_subprogram)
<1bb8e> DW_AT_name : (indirect string, offset: 0x74d41): kernel_init
<1bb92> DW_AT_decl_file : 2
<1bb92> DW_AT_decl_line : 1440
<1bb94> DW_AT_decl_column : 18
<1bb95> DW_AT_prototyped : 1
<1bb95> DW_AT_type : <0xcc>
<1bb99> DW_AT_low_pc : 0xffffffff81bab9e0
<1bba1> DW_AT_high_pc : 0x1b2
<1bba9> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa) <------ here
<1bbab> DW_AT_call_all_calls: 1
<1bbab> DW_AT_sibling : <0x1bf5a>
While clang sets it to a register directly and it can check the register
and offset in the instruction directly.
<1><43d1542>: Abbrev Number: 60 (DW_TAG_subprogram)
<43d1543> DW_AT_low_pc : 0xffffffff816a7c60
<43d154b> DW_AT_high_pc : 0x98
<43d154f> DW_AT_frame_base : 1 byte block: 56 (DW_OP_reg6 (rbp)) <---------- here
<43d1551> DW_AT_GNU_all_call_sites: 1
<43d1551> DW_AT_name : (indirect string, offset: 0x3bce91): foo
<43d1555> DW_AT_decl_file : 1
<43d1556> DW_AT_decl_line : 75
<43d1557> DW_AT_prototyped : 1
<43d1557> DW_AT_type : <0x43c7332>
<43d155b> DW_AT_external : 1
Also it needs to update the offset after finding the type like global
variables since the offset was from the frame base. Factor out
match_var_offset() to check global and local variables in the same way.
The type stats are improved too:
Annotate data type stats:
total 294, ok 160 (54.4%), bad 134 (45.6%)
-----------------------------------------------------------
30 : no_sym
32 : no_mem_ops
51 : no_var
14 : no_typeinfo
7 : bad_offset
Reviewed-by: Ian Rogers <irogers@google.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20240117062657.985479-9-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
199 lines
6.4 KiB
C
199 lines
6.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#ifndef _DWARF_AUX_H
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#define _DWARF_AUX_H
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/*
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* dwarf-aux.h : libdw auxiliary interfaces
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*/
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#include <dwarf.h>
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#include <elfutils/libdw.h>
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#include <elfutils/libdwfl.h>
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#include <elfutils/version.h>
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struct strbuf;
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/* Find the realpath of the target file */
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const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname);
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/* Get DW_AT_comp_dir (should be NULL with older gcc) */
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const char *cu_get_comp_dir(Dwarf_Die *cu_die);
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/* Get a line number and file name for given address */
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int cu_find_lineinfo(Dwarf_Die *cudie, Dwarf_Addr addr,
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const char **fname, int *lineno);
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/* Walk on functions at given address */
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int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
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int (*callback)(Dwarf_Die *, void *), void *data);
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/* Get DW_AT_linkage_name (should be NULL for C binary) */
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const char *die_get_linkage_name(Dwarf_Die *dw_die);
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/* Get the lowest PC in DIE (including range list) */
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int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr);
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/* Ensure that this DIE is a subprogram and definition (not declaration) */
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bool die_is_func_def(Dwarf_Die *dw_die);
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/* Ensure that this DIE is an instance of a subprogram */
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bool die_is_func_instance(Dwarf_Die *dw_die);
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/* Compare diename and tname */
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bool die_compare_name(Dwarf_Die *dw_die, const char *tname);
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/* Matching diename with glob pattern */
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bool die_match_name(Dwarf_Die *dw_die, const char *glob);
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/* Get callsite line number of inline-function instance */
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int die_get_call_lineno(Dwarf_Die *in_die);
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/* Get callsite file name of inlined function instance */
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const char *die_get_call_file(Dwarf_Die *in_die);
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/* Get declared file name of a DIE */
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const char *die_get_decl_file(Dwarf_Die *dw_die);
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/* Get type die */
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Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem);
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/* Get a type die, but skip qualifiers and typedef */
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Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem);
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/* Check whether the DIE is signed or not */
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bool die_is_signed_type(Dwarf_Die *tp_die);
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/* Get data_member_location offset */
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int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs);
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/* Return values for die_find_child() callbacks */
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enum {
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DIE_FIND_CB_END = 0, /* End of Search */
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DIE_FIND_CB_CHILD = 1, /* Search only children */
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DIE_FIND_CB_SIBLING = 2, /* Search only siblings */
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DIE_FIND_CB_CONTINUE = 3, /* Search children and siblings */
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};
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/* Search child DIEs */
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Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
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int (*callback)(Dwarf_Die *, void *),
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void *data, Dwarf_Die *die_mem);
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/* Search a non-inlined function including given address */
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Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
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Dwarf_Die *die_mem);
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/* Search a non-inlined function with tail call at given address */
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Dwarf_Die *die_find_tailfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
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Dwarf_Die *die_mem);
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/* Search the top inlined function including given address */
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Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
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Dwarf_Die *die_mem);
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/* Search the deepest inlined function including given address */
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Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
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Dwarf_Die *die_mem);
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/* Walk on the instances of given DIE */
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int die_walk_instances(Dwarf_Die *in_die,
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int (*callback)(Dwarf_Die *, void *), void *data);
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/* Walker on lines (Note: line number will not be sorted) */
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typedef int (* line_walk_callback_t) (const char *fname, int lineno,
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Dwarf_Addr addr, void *data);
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/*
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* Walk on lines inside given DIE. If the DIE is a subprogram, walk only on
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* the lines inside the subprogram, otherwise the DIE must be a CU DIE.
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*/
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int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data);
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/* Find a variable called 'name' at given address */
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Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
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Dwarf_Addr addr, Dwarf_Die *die_mem);
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/* Find a member called 'name' */
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Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
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Dwarf_Die *die_mem);
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/* Get the name of given type DIE */
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int die_get_typename_from_type(Dwarf_Die *type_die, struct strbuf *buf);
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/* Get the name of given variable DIE */
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int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf);
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/* Get the name and type of given variable DIE, stored as "type\tname" */
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int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf);
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/* Check if target program is compiled with optimization */
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bool die_is_optimized_target(Dwarf_Die *cu_die);
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/* Use next address after prologue as probe location */
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void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,
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Dwarf_Addr *entrypc);
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/* Get the list of including scopes */
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int die_get_scopes(Dwarf_Die *cu_die, Dwarf_Addr pc, Dwarf_Die **scopes);
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#ifdef HAVE_DWARF_GETLOCATIONS_SUPPORT
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/* Get byte offset range of given variable DIE */
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int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf);
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/* Find a variable saved in the 'reg' at given address */
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Dwarf_Die *die_find_variable_by_reg(Dwarf_Die *sc_die, Dwarf_Addr pc, int reg,
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int *poffset, bool is_fbreg,
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Dwarf_Die *die_mem);
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/* Find a (global) variable located in the 'addr' */
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Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die, Dwarf_Addr pc,
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Dwarf_Addr addr, Dwarf_Die *die_mem,
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int *offset);
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#else /* HAVE_DWARF_GETLOCATIONS_SUPPORT */
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static inline int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
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Dwarf_Die *vr_die __maybe_unused,
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struct strbuf *buf __maybe_unused)
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{
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return -ENOTSUP;
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}
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static inline Dwarf_Die *die_find_variable_by_reg(Dwarf_Die *sc_die __maybe_unused,
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Dwarf_Addr pc __maybe_unused,
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int reg __maybe_unused,
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int *poffset __maybe_unused,
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bool is_fbreg __maybe_unused,
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Dwarf_Die *die_mem __maybe_unused)
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{
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return NULL;
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}
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static inline Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die __maybe_unused,
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Dwarf_Addr pc __maybe_unused,
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Dwarf_Addr addr __maybe_unused,
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Dwarf_Die *die_mem __maybe_unused,
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int *offset __maybe_unused)
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{
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return NULL;
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}
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#endif /* HAVE_DWARF_GETLOCATIONS_SUPPORT */
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#ifdef HAVE_DWARF_CFI_SUPPORT
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/* Get the frame base information from CFA */
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int die_get_cfa(Dwarf *dwarf, u64 pc, int *preg, int *poffset);
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#else /* HAVE_DWARF_CFI_SUPPORT */
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static inline int die_get_cfa(Dwarf *dwarf __maybe_unused, u64 pc __maybe_unused,
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int *preg __maybe_unused, int *poffset __maybe_unused)
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{
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return -1;
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}
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#endif /* HAVE_DWARF_CFI_SUPPORT */
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#endif /* _DWARF_AUX_H */
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