debug info problems about address-sanitizer HOT 13 CLOSED

-Stability+1: crashes in the libc stack unwinder on Android. Only happen when 
main() is instrumented. I can only explain this by the incorrect debug info. 
May be related to http://llvm.org/bugs/show_bug.cgi?id=11468 (incorrect debug 
info with aligned stack variables).

Notes on the progress:
Exceptions (PR11468): Call frame information is incorrect in case the stack is 
aligned. I see no short quick fix for this bug at the moment. eugenis@, does 
this happen on ARM? The code that emits function prologue is target-specific, 
so probably it's incorrect both on X86 and ARM.

Debug Info Quality: fixed little bug with debug info in presence of aligned 
stack, but it didn't help ASan - have to dig deeper.

Debug Info Size: Clang option -gline-tables-only submitted to trunk and is 
being tested. This option increases the size of the binary by about 2x (instead 
of 4-5x with regular -g) and produces stack traces with files and line numbers.

Thanks for working on this. The "Debug info quality" problem (11818) seems to 
be the most severe for us at the moment because it makes it pretty much 
impossible to debug any ASan failures with GDB in Firefox or Spidermonkey.

-gline-tables-only looks good so far, with the only problem that it does not 
save the 
full function names.
I.e. instead of AAA::BBB::CCC(int, int) it will just have CCC.
This is not a big deal if we can extract the function name from the symbol in 
the binary, but it hurts if we have some inlined frames.
-gline-tables-only can be fixed to actually store the full function names, but 
it will
cost some debug info size. 
Alexey, please measure the difference and update this bug. 

PR11468 is fixed in r160248.

Is there any update on the second point? I'm still seeing lots of "<optimized 
out>" in debug-only builds. I was just trying again to debug an ASan failure 
under GDB but it's pretty much impossible.

No, full debug info (the ability to trace variable/argument values) is still 
broken with ASan. We hope to fix this soon, but I can't give the exact date 
when it is done...

[deleted comment]

r169984 makes ASan + "-g" + gdb much more usable (I can now observe values of 
local variables and function arguments). I would be happy to hear from 
decoder.oh if it works for Firefox/Spidermonkey. Closing this issue for now. 
Feel free to file debug info problems or bugs as separate (hopefully, not 
major) issues.

Can we get Chromium's clang revision rolled past this change. Please. Pretty 
please.

Right now Chromium is at clang r169803, according to 
tools/clang/scripts/update.sh

Stephen, you need this for debugging, right?
You can refer to http://dev.chromium.org/developers/testing/addresssanitizer 
for the instructions on how to build Chromium with a custom Clang (and 
code.google.com/p/address-sanitizer/wiki/HowToBuild for Clang build 
instructions).

Moreover, you can fix tools/clang/scripts/update.sh to point to this revision 
(you'll also need to work around the Android flag in that script). Then running 
update.sh will download and build the corresponding Clang version for you.

Adding Project:AddressSanitizer as part of GitHub migration.