1804011 - Avoid possible assertion failures in FunctionCompiler::emitInstanceCall

Status: RESOLVED FIXED

(Core :: JavaScript: WebAssembly, defect)

Description

[Julian Seward [:jseward]]

Bug 1799856 D163112 added a helper method FunctionCompiler::emitInstanceCall.
Although this is believed always to generate correct MIR, the assertions
relating to number-of-arguments have been observed to fail in the case where
we're currently in dead code. In that case some of the actual arguments
(MDefinition*s) can be null, which causes the actual args to be
under-counted.

Given that ::passInstance, ::passArg, ::finishCall and
::builtinInstanceMethodCall are all no-ops in dead code, this routine
generates no MIR in dead code, so a simple fix is to add a dead-code check to
this routine too.

Comment 1

[Julian Seward [:jseward]]

Attachment: Bug 1804011 - Avoid possible assertion failures in FunctionCompiler::emitInstanceCall. r=rhunt.

Bug 1799856 D163112 added a helper method FunctionCompiler::emitInstanceCall.
Although this is believed always to generate correct MIR, the assertions
relating to number-of-arguments have been observed to fail in the case where
we're currently in dead code. In that case some of the actual arguments
(MDefinition*s) can be null, which causes the actual args to be
under-counted.

Given that ::passInstance, ::passArg, ::finishCall and
::builtinInstanceMethodCall are all no-ops in dead code, this routine
generates no MIR in dead code, so a simple fix is to add a dead-code check to
this routine too.

Comment 2

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/2f6c696def9f