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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "jit/BaselineFrameInfo.h"
#ifdef DEBUG
# include "jit/BytecodeAnalysis.h"
#endif
#include "jit/BaselineFrameInfo-inl.h"
#include "jit/MacroAssembler-inl.h"
using namespace js;
using namespace js::jit;
bool
FrameInfo::init(TempAllocator& alloc)
{
// An extra slot is needed for global scopes because INITGLEXICAL (stack
// depth 1) is compiled as a SETPROP (stack depth 2) on the global lexical
// scope.
size_t extra = script->isGlobalCode() ? 1 : 0;
size_t nstack = Max(script->nslots() - script->nfixed(), size_t(MinJITStackSize)) + extra;
if (!stack.init(alloc, nstack))
return false;
return true;
}
void
FrameInfo::sync(StackValue* val)
{
switch (val->kind()) {
case StackValue::Stack:
break;
case StackValue::LocalSlot:
masm.pushValue(addressOfLocal(val->localSlot()));
break;
case StackValue::ArgSlot:
masm.pushValue(addressOfArg(val->argSlot()));
break;
case StackValue::ThisSlot:
masm.pushValue(addressOfThis());
break;
case StackValue::EvalNewTargetSlot:
MOZ_ASSERT(script->isForEval());
masm.pushValue(addressOfEvalNewTarget());
break;
case StackValue::Register:
masm.pushValue(val->reg());
break;
case StackValue::Constant:
masm.pushValue(val->constant());
break;
default:
MOZ_CRASH("Invalid kind");
}
val->setStack();
}
void
FrameInfo::syncStack(uint32_t uses)
{
MOZ_ASSERT(uses <= stackDepth());
uint32_t depth = stackDepth() - uses;
for (uint32_t i = 0; i < depth; i++) {
StackValue* current = &stack[i];
sync(current);
}
}
uint32_t
FrameInfo::numUnsyncedSlots()
{
// Start at the bottom, find the first value that's not synced.
uint32_t i = 0;
for (; i < stackDepth(); i++) {
if (peek(-int32_t(i + 1))->kind() == StackValue::Stack)
break;
}
return i;
}
void
FrameInfo::popValue(ValueOperand dest)
{
StackValue* val = peek(-1);
switch (val->kind()) {
case StackValue::Constant:
masm.moveValue(val->constant(), dest);
break;
case StackValue::LocalSlot:
masm.loadValue(addressOfLocal(val->localSlot()), dest);
break;
case StackValue::ArgSlot:
masm.loadValue(addressOfArg(val->argSlot()), dest);
break;
case StackValue::ThisSlot:
masm.loadValue(addressOfThis(), dest);
break;
case StackValue::EvalNewTargetSlot:
masm.loadValue(addressOfEvalNewTarget(), dest);
break;
case StackValue::Stack:
masm.popValue(dest);
break;
case StackValue::Register:
masm.moveValue(val->reg(), dest);
break;
default:
MOZ_CRASH("Invalid kind");
}
// masm.popValue already adjusted the stack pointer, don't do it twice.
pop(DontAdjustStack);
}
void
FrameInfo::popRegsAndSync(uint32_t uses)
{
// x86 has only 3 Value registers. Only support 2 regs here for now,
// so that there's always a scratch Value register for reg -> reg
// moves.
MOZ_ASSERT(uses > 0);
MOZ_ASSERT(uses <= 2);
MOZ_ASSERT(uses <= stackDepth());
syncStack(uses);
switch (uses) {
case 1:
popValue(R0);
break;
case 2: {
// If the second value is in R1, move it to R2 so that it's not
// clobbered by the first popValue.
StackValue* val = peek(-2);
if (val->kind() == StackValue::Register && val->reg() == R1) {
masm.moveValue(R1, R2);
val->setRegister(R2);
}
popValue(R1);
popValue(R0);
break;
}
default:
MOZ_CRASH("Invalid uses");
}
}
#ifdef DEBUG
void
FrameInfo::assertValidState(const BytecodeInfo& info)
{
// Check stack depth.
MOZ_ASSERT(stackDepth() == info.stackDepth);
// Start at the bottom, find the first value that's not synced.
uint32_t i = 0;
for (; i < stackDepth(); i++) {
if (stack[i].kind() != StackValue::Stack)
break;
}
// Assert all values on top of it are also not synced.
for (; i < stackDepth(); i++)
MOZ_ASSERT(stack[i].kind() != StackValue::Stack);
// Assert every Value register is used by at most one StackValue.
// R2 is used as scratch register by the compiler and FrameInfo,
// so it shouldn't be used for StackValues.
bool usedR0 = false, usedR1 = false;
for (i = 0; i < stackDepth(); i++) {
if (stack[i].kind() == StackValue::Register) {
ValueOperand reg = stack[i].reg();
if (reg == R0) {
MOZ_ASSERT(!usedR0);
usedR0 = true;
} else if (reg == R1) {
MOZ_ASSERT(!usedR1);
usedR1 = true;
} else {
MOZ_CRASH("Invalid register");
}
}
}
}
#endif
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