Handle block helper functions in Breakpad symbol parser.

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
Committed: https://code.google.com/p/google-breakpad/source/detail?r=1214

[Mark Mentovai]

LGTM.

Also, what’s the file in this case? (FILE 3160) If something is perhaps wrong
with the debuginfo, we should try to get it fixed.

[Mark Mentovai]

Oh, those aren’t real functions, they’re blocks helpers

http://clang.llvm.org/docs/Block-ABI-Apple.html
and
llvm/tools/clang/lib/CodeGen/CGBlocks.cpp

so they’re associated with a file but don’t get real line numbers.

[Ivan Penkov]

On 2013/09/06 20:45:25, Mark Mentovai wrote:
> Oh, those aren’t real functions, they’re blocks helpers
> 
> http://clang.llvm.org/docs/Block-ABI-Apple.html
> and
> llvm/tools/clang/lib/CodeGen/CGBlocks.cpp
> 
> so they’re associated with a file but don’t get real line numbers.

Cool.  Thanks for the link on blocks helpers.