Add support for Win64 stack unwind data as STACK CFI

Add support for Win64 stack unwind data as STACK CFI

This CL was based on https://breakpad.appspot.com/345002/

BUG=572
TEST=Run dump_syms_unittest after compiling dump_syms_regtest.cc with x64
toolchain

[Mark Mentovai]

Ted reviewed the original CL, he should have an opportunity to chime in on this
one too.

[Ted Mielczarek]

This LGTM, keeping in mind that the patch here was based on code I originally
wrote. It's been long enough that all the technical details are paged out, so I
can't give it a very thorough review (but again, the meaty bits are all mine
anyway).

We should probably figure out how to get this data out of PDB files if it
exists, if for nothing else than getting good unwind data out of Windows system
symbols from Microsoft's symbol server. Microsoft claims the data is there:
http://connect.microsoft.com/VisualStudio/feedback/details/790329/cannot-get-...

...but even with those hints I couldn't figure out exactly how to get it.
Probably if someone spent a few hours poking at it it'd be solveable.

https://breakpad.appspot.com/1264002/diff/1/common/windows/pdb_source_line_wr...
File common/windows/pdb_source_line_writer.cc (right):

https://breakpad.appspot.com/1264002/diff/1/common/windows/pdb_source_line_wr...
common/windows/pdb_source_line_writer.cc:99: //   OPTIONAL ULONG
exception_data[];
We could probably just remove this with a comment that the struct contains more
information.

https://breakpad.appspot.com/1264002/diff/1/common/windows/pdb_source_line_wr...
common/windows/pdb_source_line_writer.cc:713: while (unwind_info);
I don't see a mention of this in the style guide, but can you move this while up
to the line with the closing brace? It's confusing to me formatted like this.

[Mark Mentovai]

LGTM. Very cool.

https://breakpad.appspot.com/1264002/diff/60001/common/windows/pdb_source_lin...
File common/windows/pdb_source_line_writer.cc (right):

https://breakpad.appspot.com/1264002/diff/60001/common/windows/pdb_source_lin...
common/windows/pdb_source_line_writer.cc:61: union UnwindCode {
Minor stylish nits: use 2-space indent inside union, struct, enum.

https://breakpad.appspot.com/1264002/diff/60001/common/windows/pdb_source_lin...
common/windows/pdb_source_line_writer.cc:655: if(unwind_code->operation_info ==
0) {
Another minor stylish nit: I see “if(” and “switch(” appearing a few times in
this file. There should be a space after the keyword for these statements.

https://breakpad.appspot.com/1264002/diff/60001/common/windows/pdb_source_lin...
common/windows/pdb_source_line_writer.cc:656: stack_size += (unwind_code +
1)->frame_offset * 8;
In cases like this, do you want to make sure that c + 1 is within the proper
unwind_info->count_of_codes range?

[Will Harris]

PTAL

https://breakpad.appspot.com/1264002/diff/1/common/windows/pdb_source_line_wr...
File common/windows/pdb_source_line_writer.cc (right):

https://breakpad.appspot.com/1264002/diff/1/common/windows/pdb_source_line_wr...
common/windows/pdb_source_line_writer.cc:99: //   OPTIONAL ULONG
exception_data[];
On 2014/03/21 15:58:26, Ted Mielczarek wrote:
> We could probably just remove this with a comment that the struct contains
more
> information.

Done.

https://breakpad.appspot.com/1264002/diff/1/common/windows/pdb_source_line_wr...
common/windows/pdb_source_line_writer.cc:713: while (unwind_info);
On 2014/03/21 15:58:26, Ted Mielczarek wrote:
> I don't see a mention of this in the style guide, but can you move this while
up
> to the line with the closing brace? It's confusing to me formatted like this.

Done.

https://breakpad.appspot.com/1264002/diff/60001/common/windows/pdb_source_lin...
File common/windows/pdb_source_line_writer.cc (right):

https://breakpad.appspot.com/1264002/diff/60001/common/windows/pdb_source_lin...
common/windows/pdb_source_line_writer.cc:61: union UnwindCode {
On 2014/03/21 20:33:04, Mark Mentovai wrote:
> Minor stylish nits: use 2-space indent inside union, struct, enum.

Done.

https://breakpad.appspot.com/1264002/diff/60001/common/windows/pdb_source_lin...
common/windows/pdb_source_line_writer.cc:655: if(unwind_code->operation_info ==
0) {
On 2014/03/21 20:33:04, Mark Mentovai wrote:
> Another minor stylish nit: I see “if(” and “switch(” appearing a few
times in
> this file. There should be a space after the keyword for these statements.

Done.

https://breakpad.appspot.com/1264002/diff/60001/common/windows/pdb_source_lin...
common/windows/pdb_source_line_writer.cc:656: stack_size += (unwind_code +
1)->frame_offset * 8;
On 2014/03/21 20:33:04, Mark Mentovai wrote:
> In cases like this, do you want to make sure that c + 1 is within the proper
> unwind_info->count_of_codes range?

Done.

[Ted Mielczarek]

Please make sure you credit Mikhail I. Izmestev <izmmishao5@gmail.com> for the
original version of this patch.

[Will Harris]

Yes, certainly will credit original author in the commit.  I've created a new
patch https://breakpad.appspot.com/1274002/ which is correctly based (I was
using upload.py before) so once that gets LGTM I'll push the change.