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/shared/Lowering-shared-inl.h"
michael@0: 
michael@0: #include "jit/LIR.h"
michael@0: #include "jit/MIR.h"
michael@0: 
michael@0: using namespace js;
michael@0: using namespace jit;
michael@0: 
michael@0: bool
michael@0: LIRGeneratorShared::visitConstant(MConstant *ins)
michael@0: {
michael@0:     const Value &v = ins->value();
michael@0:     switch (ins->type()) {
michael@0:       case MIRType_Boolean:
michael@0:         return define(new(alloc()) LInteger(v.toBoolean()), ins);
michael@0:       case MIRType_Int32:
michael@0:         return define(new(alloc()) LInteger(v.toInt32()), ins);
michael@0:       case MIRType_String:
michael@0:         return define(new(alloc()) LPointer(v.toString()), ins);
michael@0:       case MIRType_Object:
michael@0:         return define(new(alloc()) LPointer(&v.toObject()), ins);
michael@0:       default:
michael@0:         // Constants of special types (undefined, null) should never flow into
michael@0:         // here directly. Operations blindly consuming them require a Box.
michael@0:         JS_ASSERT(!"unexpected constant type");
michael@0:         return false;
michael@0:     }
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorShared::defineTypedPhi(MPhi *phi, size_t lirIndex)
michael@0: {
michael@0:     LPhi *lir = current->getPhi(lirIndex);
michael@0: 
michael@0:     uint32_t vreg = getVirtualRegister();
michael@0:     if (vreg >= MAX_VIRTUAL_REGISTERS)
michael@0:         return false;
michael@0: 
michael@0:     phi->setVirtualRegister(vreg);
michael@0:     lir->setDef(0, LDefinition(vreg, LDefinition::TypeFrom(phi->type())));
michael@0:     annotate(lir);
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: void
michael@0: LIRGeneratorShared::lowerTypedPhiInput(MPhi *phi, uint32_t inputPosition, LBlock *block, size_t lirIndex)
michael@0: {
michael@0:     MDefinition *operand = phi->getOperand(inputPosition);
michael@0:     LPhi *lir = block->getPhi(lirIndex);
michael@0:     lir->setOperand(inputPosition, LUse(operand->virtualRegister(), LUse::ANY));
michael@0: }
michael@0: 
michael@0: LRecoverInfo *
michael@0: LIRGeneratorShared::getRecoverInfo(MResumePoint *rp)
michael@0: {
michael@0:     if (cachedRecoverInfo_ && cachedRecoverInfo_->mir() == rp)
michael@0:         return cachedRecoverInfo_;
michael@0: 
michael@0:     LRecoverInfo *recoverInfo = LRecoverInfo::New(gen, rp);
michael@0:     if (!recoverInfo)
michael@0:         return nullptr;
michael@0: 
michael@0:     cachedRecoverInfo_ = recoverInfo;
michael@0:     return recoverInfo;
michael@0: }
michael@0: 
michael@0: #ifdef JS_NUNBOX32
michael@0: LSnapshot *
michael@0: LIRGeneratorShared::buildSnapshot(LInstruction *ins, MResumePoint *rp, BailoutKind kind)
michael@0: {
michael@0:     LRecoverInfo *recover = getRecoverInfo(rp);
michael@0:     if (!recover)
michael@0:         return nullptr;
michael@0: 
michael@0:     LSnapshot *snapshot = LSnapshot::New(gen, recover, kind);
michael@0:     if (!snapshot)
michael@0:         return nullptr;
michael@0: 
michael@0:     size_t i = 0;
michael@0:     for (MResumePoint **it = recover->begin(), **end = recover->end(); it != end; ++it) {
michael@0:         MResumePoint *mir = *it;
michael@0:         for (size_t j = 0, e = mir->numOperands(); j < e; ++i, ++j) {
michael@0:             MDefinition *ins = mir->getOperand(j);
michael@0: 
michael@0:             LAllocation *type = snapshot->typeOfSlot(i);
michael@0:             LAllocation *payload = snapshot->payloadOfSlot(i);
michael@0: 
michael@0:             if (ins->isBox())
michael@0:                 ins = ins->toBox()->getOperand(0);
michael@0: 
michael@0:             // Guards should never be eliminated.
michael@0:             JS_ASSERT_IF(ins->isUnused(), !ins->isGuard());
michael@0: 
michael@0:             // Snapshot operands other than constants should never be
michael@0:             // emitted-at-uses. Try-catch support depends on there being no
michael@0:             // code between an instruction and the LOsiPoint that follows it.
michael@0:             JS_ASSERT_IF(!ins->isConstant(), !ins->isEmittedAtUses());
michael@0: 
michael@0:             // The register allocation will fill these fields in with actual
michael@0:             // register/stack assignments. During code generation, we can restore
michael@0:             // interpreter state with the given information. Note that for
michael@0:             // constants, including known types, we record a dummy placeholder,
michael@0:             // since we can recover the same information, much cleaner, from MIR.
michael@0:             if (ins->isConstant() || ins->isUnused()) {
michael@0:                 *type = LConstantIndex::Bogus();
michael@0:                 *payload = LConstantIndex::Bogus();
michael@0:             } else if (ins->type() != MIRType_Value) {
michael@0:                 *type = LConstantIndex::Bogus();
michael@0:                 *payload = use(ins, LUse::KEEPALIVE);
michael@0:             } else {
michael@0:                 *type = useType(ins, LUse::KEEPALIVE);
michael@0:                 *payload = usePayload(ins, LUse::KEEPALIVE);
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     return snapshot;
michael@0: }
michael@0: 
michael@0: #elif JS_PUNBOX64
michael@0: 
michael@0: LSnapshot *
michael@0: LIRGeneratorShared::buildSnapshot(LInstruction *ins, MResumePoint *rp, BailoutKind kind)
michael@0: {
michael@0:     LRecoverInfo *recover = getRecoverInfo(rp);
michael@0:     if (!recover)
michael@0:         return nullptr;
michael@0: 
michael@0:     LSnapshot *snapshot = LSnapshot::New(gen, recover, kind);
michael@0:     if (!snapshot)
michael@0:         return nullptr;
michael@0: 
michael@0:     size_t i = 0;
michael@0:     for (MResumePoint **it = recover->begin(), **end = recover->end(); it != end; ++it) {
michael@0:         MResumePoint *mir = *it;
michael@0:         for (size_t j = 0, e = mir->numOperands(); j < e; ++i, ++j) {
michael@0:             MDefinition *def = mir->getOperand(j);
michael@0: 
michael@0:             if (def->isBox())
michael@0:                 def = def->toBox()->getOperand(0);
michael@0: 
michael@0:             // Guards should never be eliminated.
michael@0:             JS_ASSERT_IF(def->isUnused(), !def->isGuard());
michael@0: 
michael@0:             // Snapshot operands other than constants should never be
michael@0:             // emitted-at-uses. Try-catch support depends on there being no
michael@0:             // code between an instruction and the LOsiPoint that follows it.
michael@0:             JS_ASSERT_IF(!def->isConstant(), !def->isEmittedAtUses());
michael@0: 
michael@0:             LAllocation *a = snapshot->getEntry(i);
michael@0: 
michael@0:             if (def->isUnused()) {
michael@0:                 *a = LConstantIndex::Bogus();
michael@0:                 continue;
michael@0:             }
michael@0: 
michael@0:             *a = useKeepaliveOrConstant(def);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     return snapshot;
michael@0: }
michael@0: #endif
michael@0: 
michael@0: bool
michael@0: LIRGeneratorShared::assignSnapshot(LInstruction *ins, BailoutKind kind)
michael@0: {
michael@0:     // assignSnapshot must be called before define/add, since
michael@0:     // it may add new instructions for emitted-at-use operands.
michael@0:     JS_ASSERT(ins->id() == 0);
michael@0: 
michael@0:     LSnapshot *snapshot = buildSnapshot(ins, lastResumePoint_, kind);
michael@0:     if (!snapshot)
michael@0:         return false;
michael@0: 
michael@0:     ins->assignSnapshot(snapshot);
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool
michael@0: LIRGeneratorShared::assignSafepoint(LInstruction *ins, MInstruction *mir)
michael@0: {
michael@0:     JS_ASSERT(!osiPoint_);
michael@0:     JS_ASSERT(!ins->safepoint());
michael@0: 
michael@0:     ins->initSafepoint(alloc());
michael@0: 
michael@0:     MResumePoint *mrp = mir->resumePoint() ? mir->resumePoint() : lastResumePoint_;
michael@0:     LSnapshot *postSnapshot = buildSnapshot(ins, mrp, Bailout_Normal);
michael@0:     if (!postSnapshot)
michael@0:         return false;
michael@0: 
michael@0:     osiPoint_ = new(alloc()) LOsiPoint(ins->safepoint(), postSnapshot);
michael@0: 
michael@0:     return lirGraph_.noteNeedsSafepoint(ins);
michael@0: }
michael@0: