From: Adrian Hunter <adrian.hunter@intel.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Ian Rogers <irogers@google.com>,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Subject: [PATCH 09/10] perf symbols: Combine handling for SHT_RELA and SHT_REL
Date: Fri, 20 Jan 2023 14:34:55 +0200 [thread overview]
Message-ID: <20230120123456.12449-10-adrian.hunter@intel.com> (raw)
In-Reply-To: <20230120123456.12449-1-adrian.hunter@intel.com>
SHT_REL and SHT_RELA are handled the same way. Simplify by combining the
handling.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
tools/perf/util/symbol-elf.c | 75 +++++++++++++-----------------------
1 file changed, 27 insertions(+), 48 deletions(-)
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 6e4a22acefba..e274f646ac32 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -323,6 +323,23 @@ static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
return demangled;
}
+struct rel_info {
+ bool is_rela;
+ Elf_Data *reldata;
+ GElf_Rela rela;
+ GElf_Rel rel;
+};
+
+static u32 get_rel_symidx(struct rel_info *ri, u32 idx)
+{
+ if (ri->is_rela) {
+ gelf_getrela(ri->reldata, idx, &ri->rela);
+ return GELF_R_SYM(ri->rela.r_info);
+ }
+ gelf_getrel(ri->reldata, idx, &ri->rel);
+ return GELF_R_SYM(ri->rel.r_info);
+}
+
static bool get_plt_sizes(struct dso *dso, GElf_Ehdr *ehdr, GElf_Shdr *shdr_plt,
u64 *plt_header_size, u64 *plt_entry_size)
{
@@ -353,16 +370,6 @@ static bool get_plt_sizes(struct dso *dso, GElf_Ehdr *ehdr, GElf_Shdr *shdr_plt,
}
}
-#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; \
- ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
-
-#define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
- for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
- idx < nr_entries; \
- ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
-
/*
* We need to check if we have a .dynsym, so that we can handle the
* .plt, synthesizing its symbols, that aren't on the symtabs (be it
@@ -378,13 +385,14 @@ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
GElf_Shdr shdr_plt;
struct symbol *f;
GElf_Shdr shdr_rel_plt, shdr_dynsym;
- Elf_Data *reldata, *syms, *symstrs;
+ Elf_Data *syms, *symstrs;
Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
size_t dynsym_idx;
GElf_Ehdr ehdr;
char sympltname[1024];
Elf *elf;
- int nr = 0, symidx, err = -1;
+ int nr = 0, err = -1;
+ struct rel_info ri = { .is_rela = false };
elf = ss->elf;
ehdr = ss->ehdr;
@@ -433,8 +441,8 @@ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
* Fetch the relocation section to find the idxes to the GOT
* and the symbols in the .dynsym they refer to.
*/
- reldata = elf_getdata(scn_plt_rel, NULL);
- if (reldata == NULL)
+ ri.reldata = elf_getdata(scn_plt_rel, NULL);
+ if (!ri.reldata)
goto out_elf_end;
syms = elf_getdata(scn_dynsym, NULL);
@@ -456,44 +464,15 @@ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
plt_offset = shdr_plt.sh_offset;
plt_offset += plt_header_size;
- if (shdr_rel_plt.sh_type == SHT_RELA) {
- GElf_Rela pos_mem, *pos;
+ ri.is_rela = shdr_rel_plt.sh_type == SHT_RELA;
- elf_section__for_each_rela(reldata, pos, pos_mem, idx,
- nr_rel_entries) {
+ if (shdr_rel_plt.sh_type == SHT_RELA ||
+ shdr_rel_plt.sh_type == SHT_REL) {
+ for (idx = 0; idx < nr_rel_entries; idx++) {
const char *elf_name = NULL;
char *demangled = NULL;
- symidx = GELF_R_SYM(pos->r_info);
- 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;
- if (*elf_name)
- snprintf(sympltname, sizeof(sympltname), "%s@plt", elf_name);
- else
- snprintf(sympltname, sizeof(sympltname),
- "offset_%#" PRIx64 "@plt", plt_offset);
- free(demangled);
- f = symbol__new(plt_offset, plt_entry_size,
- STB_GLOBAL, STT_FUNC, sympltname);
- if (!f)
- goto out_elf_end;
-
- plt_offset += plt_entry_size;
- symbols__insert(&dso->symbols, f);
- ++nr;
- }
- } else if (shdr_rel_plt.sh_type == SHT_REL) {
- 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);
- gelf_getsym(syms, symidx, &sym);
+ gelf_getsym(syms, get_rel_symidx(&ri, idx), &sym);
elf_name = elf_sym__name(&sym, symstrs);
demangled = demangle_sym(dso, 0, elf_name);
--
2.34.1
next prev parent reply other threads:[~2023-01-20 12:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-20 12:34 [PATCH 00/10] perf symbols: Improve dso__synthesize_plt_symbols() Adrian Hunter
2023-01-20 12:34 ` [PATCH 01/10] perf test: Add Symbols test Adrian Hunter
2023-01-20 12:34 ` [PATCH 02/10] perf symbols: Factor out get_plt_sizes() Adrian Hunter
2023-01-20 12:34 ` [PATCH 03/10] perf symbols: Check plt_entry_size is not zero Adrian Hunter
2023-01-20 12:34 ` [PATCH 04/10] perf symbols: Add dso__find_symbol_nocache() Adrian Hunter
2023-01-20 12:34 ` [PATCH 05/10] perf symbols: Slightly simplify 'err' usage in dso__synthesize_plt_symbols() Adrian Hunter
2023-01-20 12:34 ` [PATCH 06/10] perf symbols: Do not check ss->dynsym twice Adrian Hunter
2023-01-20 12:34 ` [PATCH 07/10] perf symbols: Add symbol for .plt header Adrian Hunter
2023-01-20 12:34 ` [PATCH 08/10] perf symbols: Allow for .plt entries with no symbol Adrian Hunter
2023-01-20 12:34 ` Adrian Hunter [this message]
2023-01-20 12:34 ` [PATCH 10/10] perf symbols: Check SHT_RELA and SHT_REL type earlier Adrian Hunter
2023-01-20 14:11 ` [PATCH 00/10] perf symbols: Improve dso__synthesize_plt_symbols() Arnaldo Carvalho de Melo
2023-01-21 17:53 ` Ian Rogers
2023-01-22 21:11 ` Arnaldo Carvalho de Melo
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