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a1ab1285 |
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31-Jan-2023 |
Adrian Hunter <adrian.hunter@intel.com> |
perf symbols: Allow for static executables with .plt A statically linked executable can have a .plt due to IFUNCs, in which case .symtab is used not .dynsym. Check the section header link to see if that is the case, and then use symtab instead. Example: Before: $ cat tstifunc.c #include <stdio.h> void thing1(void) { printf("thing1\n"); } void thing2(void) { printf("thing2\n"); } typedef void (*thing_fn_t)(void); thing_fn_t thing_ifunc(void) { int x; if (x & 1) return thing2; return thing1; } void thing(void) __attribute__ ((ifunc ("thing_ifunc"))); int main() { thing(); return 0; } $ gcc --version gcc (Ubuntu 11.3.0-1ubuntu1~22.04) 11.3.0 Copyright (C) 2021 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. $ gcc -static -Wall -Wextra -Wno-uninitialized -o tstifuncstatic tstifunc.c $ readelf -SW tstifuncstatic | grep 'Name\|plt\|dyn' [Nr] Name Type Address Off Size ES Flg Lk Inf Al [ 4] .rela.plt RELA 00000000004002e8 0002e8 000258 18 AI 29 20 8 [ 6] .plt PROGBITS 0000000000401020 001020 000190 00 AX 0 0 16 [20] .got.plt PROGBITS 00000000004c5000 0c4000 0000e0 08 WA 0 0 8 $ perf record -e intel_pt//u --filter 'filter main @ ./tstifuncstatic' ./tstifuncstatic thing1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.008 MB perf.data ] $ perf script --itrace=be --ns -F+flags,-event,+addr,-period,-comm,-tid,-cpu,-dso 15786.690189535: tr strt 0 [unknown] => 4017cd main+0x0 15786.690189535: tr end call 4017d5 main+0x8 => 401170 [unknown] 15786.690197660: tr strt 0 [unknown] => 4017da main+0xd 15786.690197660: tr end return 4017e0 main+0x13 => 401c1a __libc_start_call_main+0x6a After: $ perf script --itrace=be --ns -F+flags,-event,+addr,-period,-comm,-tid,-cpu,-dso 15786.690189535: tr strt 0 [unknown] => 4017cd main+0x0 15786.690189535: tr end call 4017d5 main+0x8 => 401170 thing_ifunc@plt+0x0 15786.690197660: tr strt 0 [unknown] => 4017da main+0xd 15786.690197660: tr end return 4017e0 main+0x13 => 401c1a __libc_start_call_main+0x6a Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230131131625.6964-8-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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b1d1b094 |
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30-Aug-2019 |
Arnaldo Carvalho de Melo <acme@redhat.com> |
perf symbols: Move symsrc prototypes to a separate header So that we can remove dso.h from symbol.h and reduce the header dependency tree. Fixup cases where struct dso guts are needed but were obtained via symbol.h, indirectly. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/n/tip-ip683cegt306ncu3gsz7ii21@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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