Fix unoptimized code calling a disabled code when --verify-on-transition is enabled.

Fix unoptimized code calling a disabled code when --verify-on-transition is enabled.

Unoptimized code has a static call to optimized code.
Optimized code prologue goes to the OptimizeInvokedFunction runtime.
Callee schedule for background compilation and current code set the return entries return value.
Verify-on-transition triggers a safepoint, wherein the background compiler disables the old optimized code.
The OptimizedInvokedFunction stub calls through the disabled code.
FixCallersTarget see an unoptimized caller. BOOM

Similar problem without --verify-on-transition, except the safepoint comes from BackgroundCompiler::CompileOptimized.

Fixes #26927.

R=fschneider@google.com

Committed: https://github.com/dart-lang/sdk/commit/74e6376b5c602250083b168723374dac7027cdce

[rmacnak, 2016-10-13 21:22:04]

Description was changed from

==========
Fix unoptimized code calling a disabled code when --verify-on-transition is
enabled.

Unoptimized code has a static call to optimized code.
Optimized code prologue goes to the OptimizeInvokedFunction runtime.
Callee schedule for background compilation and current code set the return
entries return value.
Verify-on-transition triggers a safepoint, wherein the background compiler
disables the old optimized code.
The OptimizedInvokedFunction stub calls through the disabled code.
FixCallersTarget see an unoptimized caller. BOOM

Issue #26927, though this probably doesn't fix the bug without
--verify-on-transition because without it exiting from the runtime call doesn't
stop for a safepoint.
==========

to

==========
Fix unoptimized code calling a disabled code when --verify-on-transition is
enabled.

Unoptimized code has a static call to optimized code.
Optimized code prologue goes to the OptimizeInvokedFunction runtime.
Callee schedule for background compilation and current code set the return
entries return value.
Verify-on-transition triggers a safepoint, wherein the background compiler
disables the old optimized code.
The OptimizedInvokedFunction stub calls through the disabled code.
FixCallersTarget see an unoptimized caller. BOOM

Similar problem without --verify-on-transition, except the safepoint comes from
BackgroundCompiler::CompileOptimized.

Fixes #26927.
==========

[rmacnak, 2016-10-13 21:23:02]

rmacnak@google.com changed reviewers:
+ fschneider@google.com

[Florian Schneider, 2016-10-13 21:27:46]

LGTM!

[rmacnak, 2016-10-13 23:06:15]

+dbc, PTAL

[rmacnak, 2016-10-14 17:01:47]

Description was changed from

==========
Fix unoptimized code calling a disabled code when --verify-on-transition is
enabled.

Unoptimized code has a static call to optimized code.
Optimized code prologue goes to the OptimizeInvokedFunction runtime.
Callee schedule for background compilation and current code set the return
entries return value.
Verify-on-transition triggers a safepoint, wherein the background compiler
disables the old optimized code.
The OptimizedInvokedFunction stub calls through the disabled code.
FixCallersTarget see an unoptimized caller. BOOM

Similar problem without --verify-on-transition, except the safepoint comes from
BackgroundCompiler::CompileOptimized.

Fixes #26927.
==========

to

==========
Fix unoptimized code calling a disabled code when --verify-on-transition is
enabled.

Unoptimized code has a static call to optimized code.
Optimized code prologue goes to the OptimizeInvokedFunction runtime.
Callee schedule for background compilation and current code set the return
entries return value.
Verify-on-transition triggers a safepoint, wherein the background compiler
disables the old optimized code.
The OptimizedInvokedFunction stub calls through the disabled code.
FixCallersTarget see an unoptimized caller. BOOM

Similar problem without --verify-on-transition, except the safepoint comes from
BackgroundCompiler::CompileOptimized.

Fixes #26927.

R=fschneider@google.com

Committed:
https://github.com/dart-lang/sdk/commit/74e6376b5c602250083b168723374dac7027cdce
==========

[rmacnak, 2016-10-14 17:01:48]

Committed patchset #3 (id:40001) manually as
74e6376b5c602250083b168723374dac7027cdce (presubmit successful).

[Florian Schneider, 2016-10-14 17:20:00]

lgtm