/*
* The strategy for this goes as follows:
*
* 1) Scan the stack, looking at all return addresses that could go into JIT
* code.
* 2) If an address corresponds to a call site registered by |callSite| during
* the last compilation, remember it.
* 3) Purge the old compiled state and return if there were no active frames of
* this script on the stack.
* 4) Fix up the stack by replacing all saved addresses with the addresses the
* new compiler gives us for the call sites.
*/
bool
Recompiler::recompile()
{
JS_ASSERT(script->hasJITCode());
Vector<PatchableAddress> normalPatches(cx);
Vector<PatchableAddress> ctorPatches(cx);
StackFrame *firstCtorFrame = NULL;
StackFrame *firstNormalFrame = NULL;
// Find all JIT'd stack frames to account for return addresses that will
// need to be patched after recompilation.
for (VMFrame *f = script->compartment->jaegerCompartment()->activeFrame();
f != NULL;
f = f->previous) {
// Scan all frames owned by this VMFrame.
StackFrame *end = f->entryfp->prev();
for (StackFrame *fp = f->fp(); fp != end; fp = fp->prev()) {
// Remember the latest frame for each type of JIT'd code, so the
// compiler will have a frame to re-JIT from.
if (!firstCtorFrame && fp->script() == script && fp->isConstructing())
firstCtorFrame = fp;
else if (!firstNormalFrame && fp->script() == script && !fp->isConstructing())
firstNormalFrame = fp;
void **addr = fp->addressOfNativeReturnAddress();
if (script->jitCtor && script->jitCtor->isValidCode(*addr)) {
if (!ctorPatches.append(findPatch(script->jitCtor, addr)))
return false;
} else if (script->jitNormal && script->jitNormal->isValidCode(*addr)) {
if (!normalPatches.append(findPatch(script->jitNormal, addr)))
return false;
}
}
void **addr = f->returnAddressLocation();
if (script->jitCtor && script->jitCtor->isValidCode(*addr)) {
if (!ctorPatches.append(findPatch(script->jitCtor, addr)))
return false;
} else if (script->jitNormal && script->jitNormal->isValidCode(*addr)) {
if (!normalPatches.append(findPatch(script->jitNormal, addr)))
return false;
}
}
Vector<CallSite> normalSites(cx);
Vector<CallSite> ctorSites(cx);
if (script->jitNormal && !saveTraps(script->jitNormal, &normalSites))
return false;
if (script->jitCtor && !saveTraps(script->jitCtor, &ctorSites))
return false;
ReleaseScriptCode(cx, script);
if (normalPatches.length() &&
!recompile(firstNormalFrame, normalPatches, normalSites)) {
return false;
}
if (ctorPatches.length() &&
!recompile(firstCtorFrame, ctorPatches, ctorSites)) {
return false;
}
return true;
}
