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Date: Thu, 1 Sep 2016 13:45:32 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ingo Molnar <mingo@...nel.org>
Cc: linux-kernel@...r.kernel.org, Milian Wolff <milian.wolff@...b.com>,
Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 06/19] perf symbols: Demangle symbols for synthesized @plt entries.
From: Milian Wolff <milian.wolff@...b.com>
The symbols in the synthesized @plt entries where not demangled before,
i.e. we could end up with entries such as:
$ perf report
Samples: 7K of event 'cycles:ppp', Event count (approx.): 6223833141
Children Self Command Shared Object Symbol
- 93.63% 28.89% lab_mandelbrot lab_mandelbrot [.] main
- 73.81% main
- 33.57% hypot
27.76% __hypot_finite
15.97% __muldc3
2.90% __muldc3@plt
2.40% _ZNK6QImage6heightEv@plt
+ 2.14% QColor::rgb
1.94% _ZNK6QImage5widthEv@plt
1.92% cabs@plt
This patch remedies this issue by also applying demangling to the
synthesized symbols. The output for the above is now:
$ perf report
Samples: 7K of event 'cycles:ppp', Event count (approx.): 6223833141
Children Self Command Shared Object Symbol
- 93.63% 28.89% lab_mandelbrot lab_mandelbrot [.] main
- 73.81% main
- 33.57% hypot
27.76% __hypot_finite
15.97% __muldc3
2.90% __muldc3@plt
2.40% QImage::height() const@plt
+ 2.14% QColor::rgb
1.94% QImage::width() const@plt
1.92% cabs@plt
Signed-off-by: Milian Wolff <milian.wolff@...b.com>
LPU-Reference: 20160830114102.30863-1-milian.wolff@...b.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
tools/perf/util/symbol-elf.c | 81 ++++++++++++++++++++++++++++----------------
1 file changed, 52 insertions(+), 29 deletions(-)
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index a811c13a74d6..fbe31eff1beb 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -206,6 +206,37 @@ Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
return NULL;
}
+static bool want_demangle(bool is_kernel_sym)
+{
+ return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
+}
+
+static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
+{
+ int demangle_flags = verbose ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
+ char *demangled = NULL;
+
+ /*
+ * We need to figure out if the object was created from C++ sources
+ * DWARF DW_compile_unit has this, but we don't always have access
+ * to it...
+ */
+ if (!want_demangle(dso->kernel || kmodule))
+ return demangled;
+
+ demangled = bfd_demangle(NULL, elf_name, demangle_flags);
+ if (demangled == NULL)
+ demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
+ else if (rust_is_mangled(demangled))
+ /*
+ * Input to Rust demangling is the BFD-demangled
+ * name which it Rust-demangles in place.
+ */
+ rust_demangle_sym(demangled);
+
+ return demangled;
+}
+
#define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
idx < nr_entries; \
@@ -301,11 +332,19 @@ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *
elf_section__for_each_rela(reldata, pos, pos_mem, idx,
nr_rel_entries) {
+ const char *elf_name = NULL;
+ char *demangled = NULL;
symidx = GELF_R_SYM(pos->r_info);
plt_offset += shdr_plt.sh_entsize;
gelf_getsym(syms, symidx, &sym);
+
+ elf_name = elf_sym__name(&sym, symstrs);
+ demangled = demangle_sym(dso, 0, elf_name);
+ if (demangled != NULL)
+ elf_name = demangled;
snprintf(sympltname, sizeof(sympltname),
- "%s@plt", elf_sym__name(&sym, symstrs));
+ "%s@plt", elf_name);
+ free(demangled);
f = symbol__new(plt_offset, shdr_plt.sh_entsize,
STB_GLOBAL, sympltname);
@@ -323,11 +362,19 @@ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *
GElf_Rel pos_mem, *pos;
elf_section__for_each_rel(reldata, pos, pos_mem, idx,
nr_rel_entries) {
+ const char *elf_name = NULL;
+ char *demangled = NULL;
symidx = GELF_R_SYM(pos->r_info);
plt_offset += shdr_plt.sh_entsize;
gelf_getsym(syms, symidx, &sym);
+
+ elf_name = elf_sym__name(&sym, symstrs);
+ demangled = demangle_sym(dso, 0, elf_name);
+ if (demangled != NULL)
+ elf_name = demangled;
snprintf(sympltname, sizeof(sympltname),
- "%s@plt", elf_sym__name(&sym, symstrs));
+ "%s@plt", elf_name);
+ free(demangled);
f = symbol__new(plt_offset, shdr_plt.sh_entsize,
STB_GLOBAL, sympltname);
@@ -775,11 +822,6 @@ static u64 ref_reloc(struct kmap *kmap)
return 0;
}
-static bool want_demangle(bool is_kernel_sym)
-{
- return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
-}
-
void __weak arch__sym_update(struct symbol *s __maybe_unused,
GElf_Sym *sym __maybe_unused) { }
@@ -1070,29 +1112,10 @@ int dso__load_sym(struct dso *dso, struct map *map,
sym.st_value -= shdr.sh_addr - shdr.sh_offset;
}
new_symbol:
- /*
- * We need to figure out if the object was created from C++ sources
- * DWARF DW_compile_unit has this, but we don't always have access
- * to it...
- */
- if (want_demangle(dso->kernel || kmodule)) {
- int demangle_flags = DMGL_NO_OPTS;
- if (verbose)
- demangle_flags = DMGL_PARAMS | DMGL_ANSI;
-
- demangled = bfd_demangle(NULL, elf_name, demangle_flags);
- if (demangled == NULL)
- demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
- else if (rust_is_mangled(demangled))
- /*
- * Input to Rust demangling is the BFD-demangled
- * name which it Rust-demangles in place.
- */
- rust_demangle_sym(demangled);
+ demangled = demangle_sym(dso, kmodule, elf_name);
+ if (demangled != NULL)
+ elf_name = demangled;
- if (demangled != NULL)
- elf_name = demangled;
- }
f = symbol__new(sym.st_value, sym.st_size,
GELF_ST_BIND(sym.st_info), elf_name);
free(demangled);
--
2.7.4
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