Improvements in positions handling in optimizing compiler.

Improvements in positions handling in optimizing compiler.

- When building binary arithmetic op and comparison restore source position of the operation itself before building operation itself after it was changed by building operands. This ensures that position recorded for operation points to the operation token instead of pointing to the rightmost operand;

- Add support for recording operands' positions and use these positions when inserting HChange instructions;

- When generating hydrogen.cfg emit H-instruction position as BCI (previously 0 was emitted), additionally on every lithium instruction emit annotation pointing to corresponding hydrogen-instruction. This allows to easily reach from deopt_id to lithium instruction and from it to hydrogen instruction and source position.

BUG=
R=danno@chromium.org

Committed: http://code.google.com/p/v8/source/detail?r=17765

[Vyacheslav Egorov (Chromium), 2013-10-28 17:22:23]

Hello!

Please take a look.

Combination of this changes make it easier to build tools that want to map
deoptimization positions to the source code.

More changes that I expect to contribute in separate CLs:

- Emitting unique IDs for compiled functions (I am still trying to figure out
where to put it on OptimizedCode. I think I will identify SharedFunctionInfo
with a pair (script_id,start_position));
 
- Printing source code of optimized functions even if disassembler is not
enabled (essential for using external tooling with Chrome which does not include
disassembler by default). Printing source code of all inlined functions;

- Threading (script_id, position) pair through the optimizing compiler, instead
of just (position). Simply tracking position does not work in multi-scripts
environment (both Chrome and node.js).

[Vyacheslav Egorov (Chromium), 2013-11-08 13:22:01]

friendly ping.

[danno, 2013-11-14 13:22:50]

lgtm

[Vyacheslav Egorov (Google), 2013-11-14 21:00:35]

Committed patchset #1 manually as r17765 (presubmit successful).

[Vyacheslav Egorov (Google), 2013-11-14 21:00:54]

Thank you for the code review.