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, 16 insertions, 16 deletions

diff --git a/tools/perf/jvmti/jvmti_agent.c b/tools/perf/jvmti/jvmti_agent.c
index cbab139de5a4..6461e02ab940 100644
--- a/tools/perf/jvmti/jvmti_agent.c
+++ b/tools/perf/jvmti/jvmti_agent.c
@@ -374,20 +374,20 @@ jvmti_write_code(void *agent, char const *sym,
 
 int
 jvmti_write_debug_info(void *agent, uint64_t code, const char *file,
-		       jvmtiAddrLocationMap const *map,
-		       jvmtiLineNumberEntry *li, jint num)
+		       jvmti_line_info_t *li, int nr_lines)
 {
-	static const char *prev_str = "\xff";
 	struct jr_code_debug_info rec;
 	size_t sret, len, size, flen;
 	size_t padding_count;
+	uint64_t addr;
+	const char *fn = file;
 	FILE *fp = agent;
 	int i;
 
 	/*
 	 * no entry to write
 	 */
-	if (!num)
+	if (!nr_lines)
 		return 0;
 
 	if (!fp) {
@@ -401,17 +401,18 @@ jvmti_write_debug_info(void *agent, uint64_t code, const char *file,
 	size            = sizeof(rec);
 	rec.p.timestamp = perf_get_timestamp();
 	rec.code_addr   = (uint64_t)(uintptr_t)code;
-	rec.nr_entry    = num;
+	rec.nr_entry    = nr_lines;
 
 	/*
 	 * on disk source line info layout:
 	 * uint64_t : addr
 	 * int      : line number
+	 * int      : column discriminator
 	 * file[]   : source file name
 	 * padding  : pad to multiple of 8 bytes
 	 */
-	size += num * (sizeof(uint64_t) + sizeof(int));
-	size += flen + (num - 1) * 2;
+	size += nr_lines * sizeof(struct debug_entry);
+	size += flen * nr_lines;
 	/*
 	 * pad to 8 bytes
 	 */
@@ -429,28 +430,27 @@ jvmti_write_debug_info(void *agent, uint64_t code, const char *file,
 	if (sret != 1)
 		goto error;
 
-	for (i = 0; i < num; i++) {
-		uint64_t addr;
+	for (i = 0; i < nr_lines; i++) {
 
-		addr = (uint64_t)map[i].start_address;
+		addr = (uint64_t)li[i].pc;
 		len  = sizeof(addr);
 		sret = fwrite_unlocked(&addr, len, 1, fp);
 		if (sret != 1)
 			goto error;
 
-		len  = sizeof(int);
+		len  = sizeof(li[0].line_number);
 		sret = fwrite_unlocked(&li[i].line_number, len, 1, fp);
 		if (sret != 1)
 			goto error;
 
-		if (i == 0) {
-			sret = fwrite_unlocked(file, flen, 1, fp);
-		} else {
-			sret = fwrite_unlocked(prev_str, 2, 1, fp);
-		}
+		len  = sizeof(li[0].discrim);
+		sret = fwrite_unlocked(&li[i].discrim, len, 1, fp);
 		if (sret != 1)
 			goto error;
 
+		sret = fwrite_unlocked(fn, flen, 1, fp);
+		if (sret != 1)
+			goto error;
 	}
 	if (padding_count)
 		sret = fwrite_unlocked(pad_bytes, padding_count, 1, fp);