Strict mode arguments do not share binding with formal parameters.

Strict mode arguments do not share binding with formal parameters.

Move strict mode flag from TemporaryScope to Scope so that it can be accessed from variable binding code.
Arguments do not alias in strict mode (ia32, x64 and arm, codegen and full codegen).
Hydrogen tolerates null arguments_shadow().
In codegen-<arch> arguments object is allocated eagerly to capture values before they get modified.

BUG=
TEST=test/mjsunit/strict-mode.js

[Martin Maly, 2011-03-06 22:40:37]

http://codereview.chromium.org/6625048/diff/1/src/ast.h
File src/ast.h (right):

http://codereview.chromium.org/6625048/diff/1/src/ast.h#newcode1689
src/ast.h:1689: contains_loops_(contains_loops),
Strict mode is now needed in scopes.cc so I had to move it from temporary scope
+ function literal to scope.

It is actually cleaner that way but with the downside of having multiple scopes
per function in the future and strict mode flag is per function ...

[Lasse Reichstein, 2011-03-07 07:54:07]

You should coordinate with Kevin, who is planning to rewrite our arguments
implementation.
Since strict mode arguments are not shared, they will need to be treated
differently in any case, so maybe your code will be sufficient for strict mode.
I'll let Kevin decide.

[Kevin Millikin (Chromium), 2011-03-07 11:46:48]

LGTM.

http://codereview.chromium.org/6625048/diff/1/src/arm/codegen-arm.cc
File src/arm/codegen-arm.cc (right):

http://codereview.chromium.org/6625048/diff/1/src/arm/codegen-arm.cc#newcode620
src/arm/codegen-arm.cc:620: ASSERT(shadow != NULL && shadow->AsSlot() != NULL ||
Parens around the && please.

http://codereview.chromium.org/6625048/diff/1/src/arm/full-codegen-arm.cc
File src/arm/full-codegen-arm.cc (right):

http://codereview.chromium.org/6625048/diff/1/src/arm/full-codegen-arm.cc#new...
src/arm/full-codegen-arm.cc:217: if (arguments_shadow != NULL) {
A bit simpler (also on the other platforms):

if (arguments_shadow != NULL) {
  // Duplicate the value; move-to-slot operation might clobber registers.
  __ mov(r3, r0);
  Move(arguments_shadow->AsSlot(), r3, r1, r2);
}
Move(arguments->AsSlot(), r0, r1, r2);

http://codereview.chromium.org/6625048/diff/1/src/hydrogen.cc
File src/hydrogen.cc (right):

http://codereview.chromium.org/6625048/diff/1/src/hydrogen.cc#newcode2238
src/hydrogen.cc:2238: scope->arguments_shadow() != NULL &&
Parens around the && please.

http://codereview.chromium.org/6625048/diff/1/src/parser.cc
File src/parser.cc (right):

http://codereview.chromium.org/6625048/diff/1/src/parser.cc#newcode656
src/parser.cc:656: TemporaryScope temp_scope(&this->temp_scope_);
Hmmm.  TemporaryScope seems like a bad name---it's not really a "scope" at all. 
It seems like a bundle of function-specific bits (literals and a loop flag).  We
already have a stack-allocated "LexicalScope" everywhere we have a
TemporaryScope, so we should probably just combine them.

Maybe roll it into the next change you make to the parser.

[Martin Maly, 2011-03-07 19:09:40]

Thanks, Kevin!

http://codereview.chromium.org/6625048/diff/1/src/arm/codegen-arm.cc
File src/arm/codegen-arm.cc (right):

http://codereview.chromium.org/6625048/diff/1/src/arm/codegen-arm.cc#newcode620
src/arm/codegen-arm.cc:620: ASSERT(shadow != NULL && shadow->AsSlot() != NULL ||
On 2011/03/07 11:46:48, Kevin Millikin wrote:
> Parens around the && please.

Done.

http://codereview.chromium.org/6625048/diff/1/src/arm/full-codegen-arm.cc
File src/arm/full-codegen-arm.cc (right):

http://codereview.chromium.org/6625048/diff/1/src/arm/full-codegen-arm.cc#new...
src/arm/full-codegen-arm.cc:217: if (arguments_shadow != NULL) {
On 2011/03/07 11:46:48, Kevin Millikin wrote:
> A bit simpler (also on the other platforms):
> 
> if (arguments_shadow != NULL) {
>   // Duplicate the value; move-to-slot operation might clobber registers.
>   __ mov(r3, r0);
>   Move(arguments_shadow->AsSlot(), r3, r1, r2);
> }
> Move(arguments->AsSlot(), r0, r1, r2);

Done.

http://codereview.chromium.org/6625048/diff/1/src/hydrogen.cc
File src/hydrogen.cc (right):

http://codereview.chromium.org/6625048/diff/1/src/hydrogen.cc#newcode2238
src/hydrogen.cc:2238: scope->arguments_shadow() != NULL &&
On 2011/03/07 11:46:48, Kevin Millikin wrote:
> Parens around the && please.

Done.

http://codereview.chromium.org/6625048/diff/1/src/parser.cc
File src/parser.cc (right):

http://codereview.chromium.org/6625048/diff/1/src/parser.cc#newcode656
src/parser.cc:656: TemporaryScope temp_scope(&this->temp_scope_);
On 2011/03/07 11:46:48, Kevin Millikin wrote:
> Hmmm.  TemporaryScope seems like a bad name---it's not really a "scope" at
all. 
> It seems like a bundle of function-specific bits (literals and a loop flag). 
We
> already have a stack-allocated "LexicalScope" everywhere we have a
> TemporaryScope, so we should probably just combine them.
> 
> Maybe roll it into the next change you make to the parser.


Putting it on my list of opportunistic changes to make.