From ab52ca7d6e2f88f2f8c5830716abffce356b09e7 Mon Sep 17 00:00:00 2001
From: "ivan.penkov@gmail.com"
 <ivan.penkov@gmail.com@4c0a9323-5329-0410-9bdc-e9ce6186880e>
Date: Thu, 19 Sep 2013 21:37:49 +0000
Subject: Handle block helper functions in Breakpad symbol parser.  Block
 helper functions are associated with a source file but not associated with
 any line number.  For such functions, the Breakpad symbol file contains 0 for
 the line numbers.  Hence, 0 should be threated as valid line number.  For
 more information on block helper functions, please, take a look at
 http://clang.llvm.org/docs/Block-ABI-Apple.html.

Here is the symbol parser output:

E0906 11:27:06.051507 22535 basic_source_line_resolver.cc:76] Line 380187: ParseLine failed
E0906 11:27:06.051614 22535 basic_source_line_resolver.cc:76] Line 380188: ParseLine failed
E0906 11:27:06.051648 22535 basic_source_line_resolver.cc:76] Line 380190: ParseLine failed
E0906 11:27:06.051679 22535 basic_source_line_resolver.cc:76] Line 380191: ParseLine failed
E0906 11:27:06.200814 22535 basic_source_line_resolver.cc:76] Line 446729: ParseLine failed

Here are the contents of the Breakpad symbol file:

FUNC 440d60 49 0 __copy_helper_block_
440d60 b 0 3160    <<<-----------  the third number is the line number
440d6b 3e 0 3160    <<<----------------------------   same here
FUNC 440db0 36 0 __destroy_helper_block_
440db0 a 0 3160    <<<----------------------------   same here
440dba 2c 0 3160    <<<----------------------------   same here
Review URL: https://breakpad.appspot.com/629002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1214 4c0a9323-5329-0410-9bdc-e9ce6186880e
---
 src/processor/basic_source_line_resolver.cc | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/processor/basic_source_line_resolver.cc b/src/processor/basic_source_line_resolver.cc
index 6fb47b3b..799045ac 100644
--- a/src/processor/basic_source_line_resolver.cc
+++ b/src/processor/basic_source_line_resolver.cc
@@ -350,7 +350,7 @@ BasicSourceLineResolver::Module::ParseFunction(char *function_line) {
 
 BasicSourceLineResolver::Line* BasicSourceLineResolver::Module::ParseLine(
     char *line_line) {
-  // <address> <line number> <source file id>
+  // <address> <size> <line number> <source file id>
   vector<char*> tokens;
   if (!Tokenize(line_line, kWhitespace, 4, &tokens)) {
     return NULL;
@@ -360,7 +360,14 @@ BasicSourceLineResolver::Line* BasicSourceLineResolver::Module::ParseLine(
   uint64_t size     = strtoull(tokens[1], NULL, 16);
   int line_number   = atoi(tokens[2]);
   int source_file   = atoi(tokens[3]);
-  if (line_number <= 0) {
+
+  // Valid line numbers normally start from 1, however there are functions that
+  // are associated with a source file but not associated with any line number
+  // (block helper function) and for such functions the symbol file contains 0
+  // for the line numbers.  Hence, 0 shoud be treated as a valid line number.
+  // For more information on block helper functions, please, take a look at:
+  // http://clang.llvm.org/docs/Block-ABI-Apple.html
+  if (line_number < 0) {
     return NULL;
   }
 
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