perf jit: add source line info support

This patch adds source line information support to perf for jitted code.

The source line info must be emitted by the runtime, such as JVMTI.

Perf injects extract the source line info from the jitdump file and adds
the corresponding .debug_lines section in the ELF image generated for
each jitted function.

The source line enables matching any address in the profile with a
source file and line number.

The improvement is visible in perf annotate with the source code
displayed alongside the assembly code.

The dwarf code leverages the support from OProfile which is also
released under GPLv2.  Copyright 2007 OProfile authors.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Carl Love <cel@us.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John McCutchan <johnmccutchan@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sonny Rao <sonnyrao@chromium.org>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1448874143-7269-5-git-send-email-eranian@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 11 insertions, 4 deletions

diff --git a/tools/perf/util/genelf.c b/tools/perf/util/genelf.c
index 145f8116ef56..c1ef805c6a8f 100644
--- a/tools/perf/util/genelf.c
+++ b/tools/perf/util/genelf.c
@@ -156,7 +156,8 @@ gen_build_id(struct buildid_note *note, unsigned long load_addr, const void *cod
  */
 int
 jit_write_elf(int fd, uint64_t load_addr, const char *sym,
-	      const void *code, int csize)
+	      const void *code, int csize,
+	      void *debug, int nr_debug_entries)
 {
 	Elf *e;
 	Elf_Data *d;
@@ -385,9 +386,15 @@ jit_write_elf(int fd, uint64_t load_addr, const char *sym,
 	shdr->sh_size = sizeof(bnote);
 	shdr->sh_entsize = 0;
 
-	if (elf_update(e, ELF_C_WRITE) < 0) {
-		warnx("elf_update 4 failed");
-		goto error;
+	if (debug && nr_debug_entries) {
+		retval = jit_add_debug_info(e, load_addr, debug, nr_debug_entries);
+		if (retval)
+			goto error;
+	} else {
+		if (elf_update(e, ELF_C_WRITE) < 0) {
+			warnx("elf_update 4 failed");
+			goto error;
+		}
 	}
 
 	retval = 0;