688552 - getApiVersionFromCallStack ignores EnterCodeContext

Status: RESOLVED WONTFIX

(Tamarin Graveyard :: Virtual Machine, defect, P3)

Description

[Stan Switzer]

The function AvmCore::getApiVersionFromCallStack is supposed to determine the API version based on the invoking user by walking the MethodFrame stack, but it incorrectly ignores CodeContext entries.

The MethodFrame stack contains both MethodEnvs and raw CodeContexts that represent points where the VM was entered on behalf of user code (say, an event dispatcher).

While crawling the stack, builtin methods are ignored since the function is trying to find the nearest invoking user code. Two problems arise: first there may be no user code on the stack (in some cases builtin code is registered as an event handler), and any MethodEnvs found after a raw CodeContext represent an entirely different entry into the VM so they are beside the point.

Comment 1

[Stan Switzer]

Attachment: Proposed fix

This patch stops looking for non-builtin MethodEnvs at the first raw CodeContext and then determines API version corresponding to that code context. You can find the API version by locating the CodeContext's toplevel's pool's API version.

This fix also addresses the issue alluded to in the FIXME comment.

Comment 2

[Tommy Reilly]

Comment on attachment 561812 [details] [diff] [review]
Proposed fix

Delicate code I'm not familiar with, deferring to the pros.   Should jodyer review as well?

Comment 3

[Rick Reitmaier]

Comment on attachment 561812 [details] [diff] [review]
Proposed fix

Seem ok.  But as we know any change related to this area requires lots and lots of testing.

Comment 4

[Tamarin Bot]

changeset: 6706:1018a267e123
user:      Tommy Reilly <[e-mail]>
summary:   Bug 688552 - getApiVersionFromCallStack ignores EnterCodeContext (author=sswitzer,r=rreitmai,sr-pending=edwsmith)

http://hg.mozilla.org/tamarin-redux/rev/1018a267e123

Comment 5

[Edwin Smith]

desperately needs a test case.

Comment 6

[Sylvestre Ledru [:Sylvestre]]

Tamarin isn't maintained anymore. WONTFIX remaining bugs.