Enable lazy compilation for non-trivial outer contexts.

Enable lazy compilation for non-trivial outer contexts.

This changes the compiler to be more aggressive about lazy compilation
of closures with non-trivial outer context. Compilation can only be
triggered with a valid outer context now. One exception is the debugger,
which can request compilation of arbitrary shared code, but it ensures
to trigger compilation only at points where no context is needed.

This relands r11782, r11783, r11790 and a minor fix.

R=ulan@chromium.org
TEST=mjsunit/debug-script-breakpoints-nested

Committed: https://code.google.com/p/v8/source/detail?r=11866

[Michael Starzinger, 2012-06-13 17:21:22]

Patch Set 1: That's just a reland of previously reviewed CLs.
Patch Set 2: That's the regression test for the layout test failure.
Patch Set 3: That's the actual fix.

[ulan, 2012-06-14 08:37:24]

LGTM. I reviewed diffs between patch sets 2/3 and 1. Rubber-stamping patch set
1.

https://chromiumcodereview.appspot.com/10543141/diff/8001/src/runtime.cc
File src/runtime.cc (right):

https://chromiumcodereview.appspot.com/10543141/diff/8001/src/runtime.cc#newc...
src/runtime.cc:11718: continue;
Instead of multiple "continue" statements, I think it would be more readable to
make a boolean variable with descriptive name (e.g.
"found_lazily_compilable_candidate") and then do a single check

if (!found...) continue.

https://chromiumcodereview.appspot.com/10543141/diff/8001/src/runtime.cc#newc...
src/runtime.cc:11774: if (target_function.is_null()) {
Maybe add ASSERT(target->allows_lazy_compilation_without_context()) ?

[Michael Starzinger, 2012-06-19 13:08:13]

Comments addressed. Landing ...

https://chromiumcodereview.appspot.com/10543141/diff/8001/src/runtime.cc
File src/runtime.cc (right):

https://chromiumcodereview.appspot.com/10543141/diff/8001/src/runtime.cc#newc...
src/runtime.cc:11718: continue;
On 2012/06/14 08:37:24, ulan wrote:
> Instead of multiple "continue" statements, I think it would be more readable
to
> make a boolean variable with descriptive name (e.g.
> "found_lazily_compilable_candidate") and then do a single check
> 
> if (!found...) continue.

Done. Named the flag "found_next_candidate", because it also considers functions
that are already compiled.

https://chromiumcodereview.appspot.com/10543141/diff/8001/src/runtime.cc#newc...
src/runtime.cc:11774: if (target_function.is_null()) {
On 2012/06/14 08:37:24, ulan wrote:
> Maybe add ASSERT(target->allows_lazy_compilation_without_context()) ?

That assert is already in SharedFunctionInfo::CompileLazy.