CallFrame* CallFrame::trueCallerFrame()
{
// this -> The callee; this is either an inlined callee in which case it already has
// a pointer to the true caller. Otherwise it contains current PC in the machine
// caller.
//
// machineCaller -> The caller according to the machine, which may be zero or
// more frames above the true caller due to inlining.
// Am I an inline call frame? If so, we're done.
if (isInlineCallFrame())
return callerFrame();
// I am a machine call frame, so the question is: is my caller a machine call frame
// that has inlines or a machine call frame that doesn't?
CallFrame* machineCaller = callerFrame()->removeHostCallFrameFlag();
if (!machineCaller)
return 0;
ASSERT(!machineCaller->isInlineCallFrame());
// Figure out how we want to get the current code location.
if (hasHostCallFrameFlag() || returnAddressIsInCtiTrampoline(returnPC()))
return machineCaller->trueCallFrameFromVMCode();
return machineCaller->trueCallFrame(returnPC());
}
CodeBlock* CallFrame::someCodeBlockForPossiblyInlinedCode()
{
if (!isInlineCallFrame())
return codeBlock();
return jsCast<FunctionExecutable*>(inlineCallFrame()->executable.get())->baselineCodeBlockFor(
inlineCallFrame()->isCall ? CodeForCall : CodeForConstruct);
}
CallFrame* CallFrame::trueCallerFrameSlow()
{
// this -> The callee; this is either an inlined callee in which case it already has
// a pointer to the true caller. Otherwise it contains current PC in the machine
// caller.
//
// machineCaller -> The caller according to the machine, which may be zero or
// more frames above the true caller due to inlining.
//
// trueCaller -> The real caller.
// Am I an inline call frame? If so, we're done.
if (isInlineCallFrame())
return callerFrame();
// I am a machine call frame, so the question is: is my caller a machine call frame
// that has inlines or a machine call frame that doesn't?
CallFrame* machineCaller = callerFrame()->removeHostCallFrameFlag();
if (!machineCaller)
return 0;
ASSERT(!machineCaller->isInlineCallFrame());
if (!machineCaller->codeBlock() || !machineCaller->codeBlock()->hasCodeOrigins())
return machineCaller; // No inlining, so machineCaller == trueCaller
// Figure out where the caller frame would have gone relative to the machine
// caller, and rematerialize it. Do so for the entire inline stack.
CodeOrigin codeOrigin = machineCaller->codeBlock()->codeOriginForReturn(returnPC());
for (InlineCallFrame* inlineCallFrame = codeOrigin.inlineCallFrame; inlineCallFrame;) {
InlineCallFrame* nextInlineCallFrame = inlineCallFrame = inlineCallFrame->caller.inlineCallFrame;
CallFrame* inlinedCaller = machineCaller + inlineCallFrame->stackOffset;
JSObject* callee = machineCaller->registers()[inlineCallFrame->calleeVR].function();
JSCell* calleeAsFunctionCell = getJSFunction(callee);
ASSERT(calleeAsFunctionCell);
JSFunction* calleeAsFunction = asFunction(calleeAsFunctionCell);
// Fill in the inlinedCaller
inlinedCaller->setCodeBlock(machineCaller->codeBlock());
inlinedCaller->setScopeChain(calleeAsFunction->scope());
if (nextInlineCallFrame)
inlinedCaller->setCallerFrame(machineCaller + nextInlineCallFrame->stackOffset);
else
inlinedCaller->setCallerFrame(machineCaller);
inlinedCaller->setInlineCallFrame(inlineCallFrame);
inlinedCaller->setArgumentCountIncludingThis(inlineCallFrame->numArgumentsIncludingThis);
inlinedCaller->setCallee(callee);
inlineCallFrame = nextInlineCallFrame;
}
return machineCaller + codeOrigin.inlineCallFrame->stackOffset;
}
CallFrame* CallFrame::trueCallFrame(AbstractPC pc)
{
// Am I an inline call frame? If so, we're done.
if (isInlineCallFrame())
return this;
// If I don't have a code block, then I'm not DFG code, so I'm the true call frame.
CodeBlock* machineCodeBlock = codeBlock();
if (!machineCodeBlock)
return this;
// If the code block does not have any code origins, then there was no inlining, so
// I'm done.
if (!machineCodeBlock->hasCodeOrigins())
return this;
// At this point the PC must be due either to the DFG, or it must be unset.
ASSERT(pc.hasJITReturnAddress() || !pc);
// Try to determine the CodeOrigin. If we don't have a pc set then the only way
// that this makes sense is if the CodeOrigin index was set in the call frame.
// FIXME: Note that you will see "Not currently in inlined code" comments below.
// Currently, we do not record code origins for code that is not inlined, because
// the only thing that we use code origins for is determining the inline stack.
// But in the future, we'll want to use this same functionality (having a code
// origin mapping for any calls out of JIT code) to determine the PC at any point
// in the stack even if not in inlined code. When that happens, the code below
// will have to change the way it detects the presence of inlining: it will always
// get a code origin, but sometimes, that code origin will not have an inline call
// frame. In that case, this method should bail and return this.
CodeOrigin codeOrigin;
if (pc.isSet()) {
ReturnAddressPtr currentReturnPC = pc.jitReturnAddress();
bool hasCodeOrigin = machineCodeBlock->codeOriginForReturn(currentReturnPC, codeOrigin);
ASSERT_UNUSED(hasCodeOrigin, hasCodeOrigin);
} else {
unsigned index = codeOriginIndexForDFG();
codeOrigin = machineCodeBlock->codeOrigin(index);
}
if (!codeOrigin.inlineCallFrame)
return this; // Not currently in inlined code.
for (InlineCallFrame* inlineCallFrame = codeOrigin.inlineCallFrame; inlineCallFrame;) {
InlineCallFrame* nextInlineCallFrame = inlineCallFrame->caller.inlineCallFrame;
CallFrame* inlinedCaller = this + inlineCallFrame->stackOffset;
JSFunction* calleeAsFunction = inlineCallFrame->callee.get();
// Fill in the inlinedCaller
inlinedCaller->setCodeBlock(machineCodeBlock);
inlinedCaller->setScopeChain(calleeAsFunction->scope());
if (nextInlineCallFrame)
inlinedCaller->setCallerFrame(this + nextInlineCallFrame->stackOffset);
else
inlinedCaller->setCallerFrame(this);
inlinedCaller->setInlineCallFrame(inlineCallFrame);
inlinedCaller->setArgumentCountIncludingThis(inlineCallFrame->arguments.size());
inlinedCaller->setCallee(calleeAsFunction);
inlineCallFrame = nextInlineCallFrame;
}
return this + codeOrigin.inlineCallFrame->stackOffset;
}