michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "jit/x86/Lowering-x86.h"
michael@0: 
michael@0: #include "jit/MIR.h"
michael@0: #include "jit/x86/Assembler-x86.h"
michael@0: 
michael@0: #include "jit/shared/Lowering-shared-inl.h"
michael@0: 
michael@0: using namespace js;
michael@0: using namespace js::jit;
michael@0: 
michael@0: LDefinition
michael@0: LIRGeneratorX86::tempForDispatchCache(MIRType outputType)
michael@0: {
michael@0:     // x86 doesn't have a scratch register and we need one for the
michael@0:     // indirect jump for dispatch-style ICs.
michael@0:     //
michael@0:     // Note that currently we only install dispatch-style ICs for parallel
michael@0:     // execution. If this assumption changes, please change it here.
michael@0:     if (gen->info().executionMode() != ParallelExecution)
michael@0:         return LDefinition::BogusTemp();
michael@0: 
michael@0:     // If we don't have an output register, we need a temp.
michael@0:     if (outputType == MIRType_None)
michael@0:         return temp();
michael@0: 
michael@0:     // If we have a double output register, we need a temp.
michael@0:     if (outputType == MIRType_Double)
michael@0:         return temp();
michael@0: 
michael@0:     // Otherwise we have a non-double output register and we can reuse it.
michael@0:     return LDefinition::BogusTemp();
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorX86::useBox(LInstruction *lir, size_t n, MDefinition *mir,
michael@0:                         LUse::Policy policy, bool useAtStart)
michael@0: {
michael@0:     JS_ASSERT(mir->type() == MIRType_Value);
michael@0: 
michael@0:     if (!ensureDefined(mir))
michael@0:         return false;
michael@0:     lir->setOperand(n, LUse(mir->virtualRegister(), policy, useAtStart));
michael@0:     lir->setOperand(n + 1, LUse(VirtualRegisterOfPayload(mir), policy, useAtStart));
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorX86::useBoxFixed(LInstruction *lir, size_t n, MDefinition *mir, Register reg1,
michael@0:                              Register reg2)
michael@0: {
michael@0:     JS_ASSERT(mir->type() == MIRType_Value);
michael@0:     JS_ASSERT(reg1 != reg2);
michael@0: 
michael@0:     if (!ensureDefined(mir))
michael@0:         return false;
michael@0:     lir->setOperand(n, LUse(reg1, mir->virtualRegister()));
michael@0:     lir->setOperand(n + 1, LUse(reg2, VirtualRegisterOfPayload(mir)));
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: LAllocation
michael@0: LIRGeneratorX86::useByteOpRegister(MDefinition *mir)
michael@0: {
michael@0:     return useFixed(mir, eax);
michael@0: }
michael@0: 
michael@0: LAllocation
michael@0: LIRGeneratorX86::useByteOpRegisterOrNonDoubleConstant(MDefinition *mir)
michael@0: {
michael@0:     return useFixed(mir, eax);
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorX86::visitBox(MBox *box)
michael@0: {
michael@0:     MDefinition *inner = box->getOperand(0);
michael@0: 
michael@0:     // If the box wrapped a double, it needs a new register.
michael@0:     if (IsFloatingPointType(inner->type()))
michael@0:         return defineBox(new(alloc()) LBoxFloatingPoint(useRegisterAtStart(inner), tempCopy(inner, 0),
michael@0:                                                         inner->type()), box);
michael@0: 
michael@0:     if (box->canEmitAtUses())
michael@0:         return emitAtUses(box);
michael@0: 
michael@0:     if (inner->isConstant())
michael@0:         return defineBox(new(alloc()) LValue(inner->toConstant()->value()), box);
michael@0: 
michael@0:     LBox *lir = new(alloc()) LBox(use(inner), inner->type());
michael@0: 
michael@0:     // Otherwise, we should not define a new register for the payload portion
michael@0:     // of the output, so bypass defineBox().
michael@0:     uint32_t vreg = getVirtualRegister();
michael@0:     if (vreg >= MAX_VIRTUAL_REGISTERS)
michael@0:         return false;
michael@0: 
michael@0:     // Note that because we're using PASSTHROUGH, we do not change the type of
michael@0:     // the definition. We also do not define the first output as "TYPE",
michael@0:     // because it has no corresponding payload at (vreg + 1). Also note that
michael@0:     // although we copy the input's original type for the payload half of the
michael@0:     // definition, this is only for clarity. PASSTHROUGH definitions are
michael@0:     // ignored.
michael@0:     lir->setDef(0, LDefinition(vreg, LDefinition::GENERAL));
michael@0:     lir->setDef(1, LDefinition(inner->virtualRegister(), LDefinition::TypeFrom(inner->type()),
michael@0:                                LDefinition::PASSTHROUGH));
michael@0:     box->setVirtualRegister(vreg);
michael@0:     return add(lir);
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorX86::visitUnbox(MUnbox *unbox)
michael@0: {
michael@0:     // An unbox on x86 reads in a type tag (either in memory or a register) and
michael@0:     // a payload. Unlike most instructions conusming a box, we ask for the type
michael@0:     // second, so that the result can re-use the first input.
michael@0:     MDefinition *inner = unbox->getOperand(0);
michael@0: 
michael@0:     if (!ensureDefined(inner))
michael@0:         return false;
michael@0: 
michael@0:     if (IsFloatingPointType(unbox->type())) {
michael@0:         LUnboxFloatingPoint *lir = new(alloc()) LUnboxFloatingPoint(unbox->type());
michael@0:         if (unbox->fallible() && !assignSnapshot(lir, unbox->bailoutKind()))
michael@0:             return false;
michael@0:         if (!useBox(lir, LUnboxFloatingPoint::Input, inner))
michael@0:             return false;
michael@0:         return define(lir, unbox);
michael@0:     }
michael@0: 
michael@0:     // Swap the order we use the box pieces so we can re-use the payload register.
michael@0:     LUnbox *lir = new(alloc()) LUnbox;
michael@0:     lir->setOperand(0, usePayloadInRegisterAtStart(inner));
michael@0:     lir->setOperand(1, useType(inner, LUse::ANY));
michael@0: 
michael@0:     if (unbox->fallible() && !assignSnapshot(lir, unbox->bailoutKind()))
michael@0:         return false;
michael@0: 
michael@0:     // Note that PASSTHROUGH here is illegal, since types and payloads form two
michael@0:     // separate intervals. If the type becomes dead before the payload, it
michael@0:     // could be used as a Value without the type being recoverable. Unbox's
michael@0:     // purpose is to eagerly kill the definition of a type tag, so keeping both
michael@0:     // alive (for the purpose of gcmaps) is unappealing. Instead, we create a
michael@0:     // new virtual register.
michael@0:     return defineReuseInput(lir, unbox, 0);
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorX86::visitReturn(MReturn *ret)
michael@0: {
michael@0:     MDefinition *opd = ret->getOperand(0);
michael@0:     JS_ASSERT(opd->type() == MIRType_Value);
michael@0: 
michael@0:     LReturn *ins = new(alloc()) LReturn;
michael@0:     ins->setOperand(0, LUse(JSReturnReg_Type));
michael@0:     ins->setOperand(1, LUse(JSReturnReg_Data));
michael@0:     return fillBoxUses(ins, 0, opd) && add(ins);
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorX86::defineUntypedPhi(MPhi *phi, size_t lirIndex)
michael@0: {
michael@0:     LPhi *type = current->getPhi(lirIndex + VREG_TYPE_OFFSET);
michael@0:     LPhi *payload = current->getPhi(lirIndex + VREG_DATA_OFFSET);
michael@0: 
michael@0:     uint32_t typeVreg = getVirtualRegister();
michael@0:     if (typeVreg >= MAX_VIRTUAL_REGISTERS)
michael@0:         return false;
michael@0: 
michael@0:     phi->setVirtualRegister(typeVreg);
michael@0: 
michael@0:     uint32_t payloadVreg = getVirtualRegister();
michael@0:     if (payloadVreg >= MAX_VIRTUAL_REGISTERS)
michael@0:         return false;
michael@0:     JS_ASSERT(typeVreg + 1 == payloadVreg);
michael@0: 
michael@0:     type->setDef(0, LDefinition(typeVreg, LDefinition::TYPE));
michael@0:     payload->setDef(0, LDefinition(payloadVreg, LDefinition::PAYLOAD));
michael@0:     annotate(type);
michael@0:     annotate(payload);
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: void
michael@0: LIRGeneratorX86::lowerUntypedPhiInput(MPhi *phi, uint32_t inputPosition, LBlock *block, size_t lirIndex)
michael@0: {
michael@0:     MDefinition *operand = phi->getOperand(inputPosition);
michael@0:     LPhi *type = block->getPhi(lirIndex + VREG_TYPE_OFFSET);
michael@0:     LPhi *payload = block->getPhi(lirIndex + VREG_DATA_OFFSET);
michael@0:     type->setOperand(inputPosition, LUse(operand->virtualRegister() + VREG_TYPE_OFFSET, LUse::ANY));
michael@0:     payload->setOperand(inputPosition, LUse(VirtualRegisterOfPayload(operand), LUse::ANY));
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorX86::visitAsmJSUnsignedToDouble(MAsmJSUnsignedToDouble *ins)
michael@0: {
michael@0:     JS_ASSERT(ins->input()->type() == MIRType_Int32);
michael@0:     LAsmJSUInt32ToDouble *lir = new(alloc()) LAsmJSUInt32ToDouble(useRegisterAtStart(ins->input()), temp());
michael@0:     return define(lir, ins);
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorX86::visitAsmJSUnsignedToFloat32(MAsmJSUnsignedToFloat32 *ins)
michael@0: {
michael@0:     JS_ASSERT(ins->input()->type() == MIRType_Int32);
michael@0:     LAsmJSUInt32ToFloat32 *lir = new(alloc()) LAsmJSUInt32ToFloat32(useRegisterAtStart(ins->input()), temp());
michael@0:     return define(lir, ins);
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorX86::visitAsmJSLoadHeap(MAsmJSLoadHeap *ins)
michael@0: {
michael@0:     MDefinition *ptr = ins->ptr();
michael@0:     LAllocation ptrAlloc;
michael@0:     JS_ASSERT(ptr->type() == MIRType_Int32);
michael@0: 
michael@0:     // For the x86 it is best to keep the 'ptr' in a register if a bounds check is needed.
michael@0:     if (ptr->isConstant() && ins->skipBoundsCheck()) {
michael@0:         int32_t ptrValue = ptr->toConstant()->value().toInt32();
michael@0:         // A bounds check is only skipped for a positive index.
michael@0:         JS_ASSERT(ptrValue >= 0);
michael@0:         ptrAlloc = LAllocation(ptr->toConstant()->vp());
michael@0:     } else {
michael@0:         ptrAlloc = useRegisterAtStart(ptr);
michael@0:     }
michael@0:     LAsmJSLoadHeap *lir = new(alloc()) LAsmJSLoadHeap(ptrAlloc);
michael@0:     return define(lir, ins);
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorX86::visitAsmJSStoreHeap(MAsmJSStoreHeap *ins)
michael@0: {
michael@0:     MDefinition *ptr = ins->ptr();
michael@0:     LAsmJSStoreHeap *lir;
michael@0:     JS_ASSERT(ptr->type() == MIRType_Int32);
michael@0: 
michael@0:     if (ptr->isConstant() && ins->skipBoundsCheck()) {
michael@0:         int32_t ptrValue = ptr->toConstant()->value().toInt32();
michael@0:         JS_ASSERT(ptrValue >= 0);
michael@0:         LAllocation ptrAlloc = LAllocation(ptr->toConstant()->vp());
michael@0:         switch (ins->viewType()) {
michael@0:           case ArrayBufferView::TYPE_INT8: case ArrayBufferView::TYPE_UINT8:
michael@0:             // See comment below.
michael@0:             lir = new(alloc()) LAsmJSStoreHeap(ptrAlloc, useFixed(ins->value(), eax));
michael@0:             break;
michael@0:           case ArrayBufferView::TYPE_INT16: case ArrayBufferView::TYPE_UINT16:
michael@0:           case ArrayBufferView::TYPE_INT32: case ArrayBufferView::TYPE_UINT32:
michael@0:           case ArrayBufferView::TYPE_FLOAT32: case ArrayBufferView::TYPE_FLOAT64:
michael@0:             // See comment below.
michael@0:             lir = new(alloc()) LAsmJSStoreHeap(ptrAlloc, useRegisterAtStart(ins->value()));
michael@0:             break;
michael@0:           default: MOZ_ASSUME_UNREACHABLE("unexpected array type");
michael@0:         }
michael@0:         return add(lir, ins);
michael@0:     }
michael@0: 
michael@0:     switch (ins->viewType()) {
michael@0:       case ArrayBufferView::TYPE_INT8: case ArrayBufferView::TYPE_UINT8:
michael@0:         // See comment for LIRGeneratorX86::useByteOpRegister.
michael@0:         lir = new(alloc()) LAsmJSStoreHeap(useRegister(ins->ptr()), useFixed(ins->value(), eax));
michael@0:         break;
michael@0:       case ArrayBufferView::TYPE_INT16: case ArrayBufferView::TYPE_UINT16:
michael@0:       case ArrayBufferView::TYPE_INT32: case ArrayBufferView::TYPE_UINT32:
michael@0:       case ArrayBufferView::TYPE_FLOAT32: case ArrayBufferView::TYPE_FLOAT64:
michael@0:         // For now, don't allow constant values. The immediate operand
michael@0:         // affects instruction layout which affects patching.
michael@0:         lir = new(alloc()) LAsmJSStoreHeap(useRegisterAtStart(ptr), useRegisterAtStart(ins->value()));
michael@0:         break;
michael@0:       default: MOZ_ASSUME_UNREACHABLE("unexpected array type");
michael@0:     }
michael@0: 
michael@0:     return add(lir, ins);
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorX86::visitStoreTypedArrayElementStatic(MStoreTypedArrayElementStatic *ins)
michael@0: {
michael@0:     // The code generated for StoreTypedArrayElementStatic is identical to that
michael@0:     // for AsmJSStoreHeap, and the same concerns apply.
michael@0:     LStoreTypedArrayElementStatic *lir;
michael@0:     switch (ins->viewType()) {
michael@0:       case ArrayBufferView::TYPE_INT8: case ArrayBufferView::TYPE_UINT8:
michael@0:       case ArrayBufferView::TYPE_UINT8_CLAMPED:
michael@0:         lir = new(alloc()) LStoreTypedArrayElementStatic(useRegister(ins->ptr()),
michael@0:                                                          useFixed(ins->value(), eax));
michael@0:         break;
michael@0:       case ArrayBufferView::TYPE_INT16: case ArrayBufferView::TYPE_UINT16:
michael@0:       case ArrayBufferView::TYPE_INT32: case ArrayBufferView::TYPE_UINT32:
michael@0:       case ArrayBufferView::TYPE_FLOAT32: case ArrayBufferView::TYPE_FLOAT64:
michael@0:         lir = new(alloc()) LStoreTypedArrayElementStatic(useRegisterAtStart(ins->ptr()),
michael@0:                                                          useRegisterAtStart(ins->value()));
michael@0:         break;
michael@0:       default: MOZ_ASSUME_UNREACHABLE("unexpected array type");
michael@0:     }
michael@0: 
michael@0:     return add(lir, ins);
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorX86::visitAsmJSLoadFuncPtr(MAsmJSLoadFuncPtr *ins)
michael@0: {
michael@0:     return define(new(alloc()) LAsmJSLoadFuncPtr(useRegisterAtStart(ins->index())), ins);
michael@0: }