Adapt source position recording and fix ScopeIterator.

Adapt source position recording and fix ScopeIterator.

The ScopeIterator uses recorded scope position - as detailed in scopes.h - and
source code positions it gets from the program counter to recreate the scope
chain. However, the rewriter did not yet record source positions for the
assignment it includes.

This CL adds source code positions for the assignment added by the rewriter. 

The ScopeIterator now uses the ScopeType from the ScopeInfo to determine if the
code being debugged is eval, function or global code instead of looking up the
result symbol.

TEST=mjsunit/debug-stepout-scope.js
BUG=v8:1824, v8:1826

[Steven, 2011-11-17 10:05:38]

PTAL.

[Steven, 2011-11-18 12:57:21]

I reverted the ScopeIterator to use statement positions and added statement
positions for every return sequence not only return statements. Only adapted the
ia32 platform this time. Will port it later.

Lasse, could you PTAL?

[Lasse Reichstein, 2011-11-21 10:16:40]

LGTM.

http://codereview.chromium.org/8585001/diff/4001/src/arm/full-codegen-arm.cc
File src/arm/full-codegen-arm.cc (right):

http://codereview.chromium.org/8585001/diff/4001/src/arm/full-codegen-arm.cc#...
src/arm/full-codegen-arm.cc:363: CodeGenerator::RecordPositions(masm_,
function()->end_position() - 1);
What if the function source doesn't have a closing brace, e.g., Function("return
42;") ?
Will this still work?

http://codereview.chromium.org/8585001/diff/4001/src/ia32/full-codegen-ia32.cc
File src/ia32/full-codegen-ia32.cc (right):

http://codereview.chromium.org/8585001/diff/4001/src/ia32/full-codegen-ia32.c...
src/ia32/full-codegen-ia32.cc:367: SetSourcePosition(function()->end_position()
- 1);
Can't the final character coincide with another scope close, e.g.,
  "with (x) y = z; "
?

http://codereview.chromium.org/8585001/diff/4001/test/mjsunit/debug-stepout-s...
File test/mjsunit/debug-stepout-scope.js (right):

http://codereview.chromium.org/8585001/diff/4001/test/mjsunit/debug-stepout-s...
test/mjsunit/debug-stepout-scope.js:141: eval("with ({x:1}) x = 1");
Try adding tests with an extra character at the end, e.g., a space. Or a
semicolon followed by a space.

[Steven, 2011-11-24 13:23:31]

I will close this issue but merge the changes into
http://codereview.chromium.org/8590027/ .
Will upload an updated patchset soon.

http://codereview.chromium.org/8585001/diff/4001/src/arm/full-codegen-arm.cc
File src/arm/full-codegen-arm.cc (right):

http://codereview.chromium.org/8585001/diff/4001/src/arm/full-codegen-arm.cc#...
src/arm/full-codegen-arm.cc:363: CodeGenerator::RecordPositions(masm_,
function()->end_position() - 1);
Søren and I came up with a different scheme when debug breaking in the return
sequence. In this case we don't use the source position anymore to learn about
the scopes. We simply return only the function scope but not any of the inner
catch/with/block scopes.

So for the ScopeIterator this hunk is not important anymore. I left it as it was
before and added test cases.
On 2011/11/21 10:16:40, Lasse Reichstein wrote:
> What if the function source doesn't have a closing brace, e.g.,
Function("return
> 42;") ?
> Will this still work?

http://codereview.chromium.org/8585001/diff/4001/src/ia32/full-codegen-ia32.cc
File src/ia32/full-codegen-ia32.cc (right):

http://codereview.chromium.org/8585001/diff/4001/src/ia32/full-codegen-ia32.c...
src/ia32/full-codegen-ia32.cc:367: SetSourcePosition(function()->end_position()
- 1);
This is not important anymore. I added special handling of the return sequence
case to the ScopeIterator.
On 2011/11/21 10:16:40, Lasse Reichstein wrote:
> Can't the final character coincide with another scope close, e.g.,
>   "with (x) y = z; "
> ?

http://codereview.chromium.org/8585001/diff/4001/test/mjsunit/debug-stepout-s...
File test/mjsunit/debug-stepout-scope.js (right):

http://codereview.chromium.org/8585001/diff/4001/test/mjsunit/debug-stepout-s...
test/mjsunit/debug-stepout-scope.js:141: eval("with ({x:1}) x = 1");
On 2011/11/21 10:16:40, Lasse Reichstein wrote:
> Try adding tests with an extra character at the end, e.g., a space. Or a
> semicolon followed by a space.

Done.