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0488568178
Support using LLVM as a disassembler method, allowing helperless
annotation in non-distro builds. (It is also much faster than
using libbfd or bfd objdump on binaries with a lot of debug
information.)
This is nearly identical to the output of llvm-objdump; there are
some very rare whitespace differences, some minor changes to demangling
(since we use perf's regular demangling and not LLVM's own) and
the occasional case where llvm-objdump makes a different choice
when multiple symbols share the same address.
It should work across all of LLVM's supported architectures, although
I've only tested 64-bit x86, and finding the right triple from perf's
idea of machine architecture can sometimes be a bit tricky. Ideally, we
should have some way of finding the triplet just from the file itself.
Committer notes:
Address this on 32-bit systems by using PRIu64 from inttypes.h
3 17.58 almalinux:9-i386 : FAIL gcc version 11.4.1 20231218 (Red Hat 11.4.1-3) (GCC)
util/llvm-c-helpers.cpp: In function ‘char* make_symbol_relative_string(dso*, const char*, u64, u64)’:
util/llvm-c-helpers.cpp:150:52: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 5 has type ‘u64’ {aka
+‘long long unsigned int’} [-Werror=format=]
150 | snprintf(buf, sizeof(buf), "%s+0x%lx",
| ~~^
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| long unsigned int
| %llx
151 | demangled ? demangled : sym_name, addr - base_addr);
| ~~~~~~~~~~~~~~~~
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| u64 {aka long long unsigned int}
cc1plus: all warnings being treated as errors
Signed-off-by: Steinar H. Gunderson <sesse@google.com>
Cc: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20240803152008.2818485-3-sesse@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
61 lines
1.9 KiB
C
61 lines
1.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __PERF_LLVM_C_HELPERS
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#define __PERF_LLVM_C_HELPERS 1
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/*
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* Helpers to call into LLVM C++ code from C, for the parts that do not have
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* C APIs.
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*/
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#include <linux/compiler.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct dso;
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struct llvm_a2l_frame {
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char* filename;
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char* funcname;
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unsigned int line;
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};
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/*
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* Implement addr2line() using libLLVM. LLVM is a C++ API, and
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* many of the linux/ headers cannot be included in a C++ compile unit,
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* so we need to make a little bridge code here. llvm_addr2line() will
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* convert the inline frame information from LLVM's internal structures
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* and put them into a flat array given in inline_frames. The caller
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* is then responsible for taking that array and convert it into perf's
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* regular inline frame structures (which depend on e.g. struct list_head).
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*
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* If the address could not be resolved, or an error occurred (e.g. OOM),
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* returns 0. Otherwise, returns the number of inline frames (which means 1
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* if the address was not part of an inlined function). If unwind_inlines
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* is set and the return code is nonzero, inline_frames will be set to
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* a newly allocated array with that length. The caller is then responsible
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* for freeing both the strings and the array itself.
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*/
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int llvm_addr2line(const char* dso_name,
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u64 addr,
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char** file,
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unsigned int* line,
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bool unwind_inlines,
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struct llvm_a2l_frame** inline_frames);
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/*
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* Simple symbolizers for addresses; will convert something like
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* 0x12345 to "func+0x123". Will return NULL if no symbol was found.
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*
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* The returned value must be freed by the caller, with free().
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*/
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char *llvm_name_for_code(struct dso *dso, const char *dso_name, u64 addr);
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char *llvm_name_for_data(struct dso *dso, const char *dso_name, u64 addr);
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#ifdef __cplusplus
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}
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#endif
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#endif /* __PERF_LLVM_C_HELPERS */
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