Hi -
I was reminded by the thread that debuginfo downloading for perf is
worth automating more. Since perf uses elfutils, recently-added
facilities to elfutils 0.178 (2019-11) already allow automated
downloading from some perf code paths. The following patch [2] builds
a little bit on that by ensuring that the downloaded debuginfo is
plopped into the $HOME/.debug/ hierarchy explicitly, and should cover
a few more code paths. Feel free to take / adapt this code as you
like.
debuginfod can also do source code downloading on the fly, but the
perf/util/srccode.c machinery would need buildids passed, and I
couldn't quickly figure it out. (Sorry, I also couldn't quickly
figure out the perf testsuite.)
[1] https://sourceware.org/elfutils/Debuginfod.html
[2]
Author: Frank Ch. Eigler <fche@xxxxxxxxxx>
Date: Mon Mar 30 16:15:47 2020 -0400
perf build-ids: fall back to debuginfod query if debuginfo not found
During a perf-record, use the -ldebuginfod API to query a debuginfod
server, should the debug data not be found in the usual system
locations. If successful, the usual $HOME/.debug dir is populated.
Signed-off-by: Frank Ch. Eigler <fche@xxxxxxxxxx>
diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 574c2e0b9d20..51e051858d21 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -48,6 +48,7 @@ FEATURE_TESTS_BASIC := \
libelf-gelf_getnote \
libelf-getshdrstrndx \
libelf-mmap \
+ libdebuginfod \
libnuma \
numa_num_possible_cpus \
libperl \
@@ -114,6 +115,7 @@ FEATURE_DISPLAY ?= \
libbfd \
libcap \
libelf \
+ libdebuginfod \
libnuma \
numa_num_possible_cpus \
libperl \
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 7ac0d8088565..1109f5ec96f7 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -26,6 +26,7 @@ FILES= \
test-libelf-gelf_getnote.bin \
test-libelf-getshdrstrndx.bin \
test-libelf-mmap.bin \
+ test-libdebuginfod.bin \
test-libnuma.bin \
test-numa_num_possible_cpus.bin \
test-libperl.bin \
@@ -155,6 +156,9 @@ endif
$(OUTPUT)test-libelf-getshdrstrndx.bin:
$(BUILD) -lelf
+$(OUTPUT)test-libdebuginfod.bin:
+ $(BUILD) -ldebuginfod
+
$(OUTPUT)test-libnuma.bin:
$(BUILD) -lnuma
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 80e55e796be9..15eeecf4ff17 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -467,6 +467,11 @@ ifndef NO_LIBELF
CFLAGS += -DHAVE_ELF_GETSHDRSTRNDX_SUPPORT
endif
+ ifeq ($(feature-libdebuginfod), 1)
+ CFLAGS += -DHAVE_DEBUGINFOD_SUPPORT
+ EXTLIBS += -ldebuginfod
+ endif
+
ifndef NO_DWARF
ifeq ($(origin PERF_HAVE_DWARF_REGS), undefined)
msg := $(warning DWARF register mappings have not been defined for architecture $(SRCARCH), DWARF support disabled);
diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index c076fc7fe025..a33d00837d81 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -31,6 +31,10 @@
#include "probe-file.h"
#include "strlist.h"
+#if HAVE_DEBUGINFOD_SUPPORT
+#include <elfutils/debuginfod.h>
+#endif
+
#include <linux/ctype.h>
#include <linux/zalloc.h>
@@ -636,6 +640,21 @@ static char *build_id_cache__find_debug(const char *sbuild_id,
if (realname && access(realname, R_OK))
zfree(&realname);
nsinfo__mountns_exit(&nsc);
+
+#if HAVE_DEBUGINFOD_SUPPORT
+ if (realname == NULL) {
+ debuginfod_client* c = debuginfod_begin();
+ if (c != NULL) {
+ int fd = debuginfod_find_debuginfo(c,
+ (const unsigned char*)sbuild_id, 0,
+ &realname);
+ if (fd >= 0)
+ close(fd); /* retaining reference by realname */
+ debuginfod_end(c);
+ }
+ }
+#endif
+
out:
free(debugfile);
return realname;
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