Bug 146484 – jsc-tailcall: Add new opcodes for tail calls

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Basile Clement]

For now, this opcode should be treated as a regular call in all backends.

[Basile Clement]

(In reply to comment #0)
> For now, this opcode should be treated as a regular call in all backends.

[Basile Clement]

(In reply to comment #1)
> (In reply to comment #0)
> > For now, this opcode should be treated as a regular call in all backends.

(Oops, messed this up)

We should not do this, since it is a semantics change. Instead, we should implement this in the LLint and baseline JIT first, then progressively implement it in the DFG and FTL.

[Basile Clement]

Created attachment 257212 [details]
Patch

[Michael Saboff]

Comment on attachment 257212 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=257212&action=review

r=me with minor fix

> Source/JavaScriptCore/llint/LowLevelInterpreter.asm:609
> +    addp CallerFrameAndPCSize, sp

I don't think ARMv7 will allow you to do math with sp register.  You'll probably need to use a temp and then move result to sp.

[Mark Lam]

(In reply to comment #4)
> > Source/JavaScriptCore/llint/LowLevelInterpreter.asm:609
> > +    addp CallerFrameAndPCSize, sp
> 
> I don't think ARMv7 will allow you to do math with sp register.  You'll
> probably need to use a temp and then move result to sp.

Are you sure?  I thought ARMv7 does allow it (hardware-wise).  Should just try a build and see what gets generated.

[Basile Clement]

(In reply to comment #5)
> (In reply to comment #4)
> > > Source/JavaScriptCore/llint/LowLevelInterpreter.asm:609
> > > +    addp CallerFrameAndPCSize, sp
> > 
> > I don't think ARMv7 will allow you to do math with sp register.  You'll
> > probably need to use a temp and then move result to sp.
> 
> Are you sure?  I thought ARMv7 does allow it (hardware-wise).  Should just
> try a build and see what gets generated.

We established it was fine since we are using the two-argument version. Old version was  trying to use the three-mode operand by adding to calleeFrame, which wouldn't work. Landing this soon.

[Basile Clement]

Landed in r187166 <http://trac.webkit.org/changeset/187166>.

[Michael Saboff]

Created attachment 257287 [details]
ARM64 test output with failures

[Michael Saboff]

Created attachment 257306 [details]
ARM32 test output with failures