https://bugs.webkit.org/show_bug.cgi?id=125331

Reviewed by Filip Pizlo.

Split loadVarargs into sizeAndAllocFrameForVarargs() and loadVarargs() in
preparation for moving onto the C stack.  sizeAndAllocFrameForVarargs() will
compute the size of the callee frame and allocate it, while loadVarargs()
actually loads the argument values.

As part of moving onto the C stack, sizeAndAllocFrameForVarargs() will be
changed to a function that just computes the size.  The caller will use that
size to allocate the new frame on the stack before calling loadVargs() and
actually making the call.

* interpreter/Interpreter.cpp:
(JSC::sizeAndAllocFrameForVarargs):
(JSC::loadVarargs):
* interpreter/Interpreter.h:
* jit/JIT.h:
* jit/JITCall.cpp:
(JSC::JIT::compileLoadVarargs):
* jit/JITCall32_64.cpp:
(JSC::JIT::compileLoadVarargs):
* jit/JITInlines.h:
(JSC::JIT::callOperation):
* jit/JITOperations.cpp:
* jit/JITOperations.h:
* llint/LLIntSlowPaths.cpp:
(JSC::LLInt::LLINT_SLOW_PATH_DECL):
* llint/LLIntSlowPaths.h:
* llint/LowLevelInterpreter.asm:
* llint/LowLevelInterpreter32_64.asm:
* llint/LowLevelInterpreter64.asm:
* runtime/VM.h:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@160244 268f45cc-cd09-0410-ab3c-d52691b4dbfc