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/*
* Copyright (C) 2013-2016 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "DFGInPlaceAbstractState.h"
#if ENABLE(DFG_JIT)
#include "CodeBlock.h"
#include "DFGBasicBlock.h"
#include "GetByIdStatus.h"
#include "JSCInlines.h"
#include "PutByIdStatus.h"
#include "StringObject.h"
namespace JSC { namespace DFG {
namespace DFGInPlaceAbstractStateInternal {
static const bool verbose = false;
}
InPlaceAbstractState::InPlaceAbstractState(Graph& graph)
: m_graph(graph)
, m_abstractValues(*graph.m_abstractValuesCache)
, m_variables(m_graph.m_codeBlock->numParameters(), graph.m_localVars)
, m_block(0)
{
}
InPlaceAbstractState::~InPlaceAbstractState() { }
void InPlaceAbstractState::beginBasicBlock(BasicBlock* basicBlock)
{
ASSERT(!m_block);
ASSERT(basicBlock->variablesAtHead.numberOfLocals() == basicBlock->valuesAtHead.numberOfLocals());
ASSERT(basicBlock->variablesAtTail.numberOfLocals() == basicBlock->valuesAtTail.numberOfLocals());
ASSERT(basicBlock->variablesAtHead.numberOfLocals() == basicBlock->variablesAtTail.numberOfLocals());
m_abstractValues.resize();
for (size_t i = 0; i < basicBlock->size(); i++) {
NodeFlowProjection::forEach(
basicBlock->at(i), [&] (NodeFlowProjection nodeProjection) {
forNode(nodeProjection).clear();
});
}
m_variables = basicBlock->valuesAtHead;
if (m_graph.m_form == SSA) {
for (NodeAbstractValuePair& entry : basicBlock->ssa->valuesAtHead) {
if (entry.node.isStillValid())
forNode(entry.node) = entry.value;
}
}
basicBlock->cfaShouldRevisit = false;
basicBlock->cfaHasVisited = true;
m_block = basicBlock;
m_isValid = true;
m_foundConstants = false;
m_branchDirection = InvalidBranchDirection;
m_structureClobberState = basicBlock->cfaStructureClobberStateAtHead;
}
static void setLiveValues(Vector<NodeAbstractValuePair>& values, const Vector<NodeFlowProjection>& live)
{
values.shrink(0);
values.reserveCapacity(live.size());
for (NodeFlowProjection node : live)
values.uncheckedAppend(NodeAbstractValuePair { node, AbstractValue() });
}
void InPlaceAbstractState::initialize()
{
for (BasicBlock* entrypoint : m_graph.m_roots) {
entrypoint->cfaShouldRevisit = true;
entrypoint->cfaHasVisited = false;
entrypoint->cfaFoundConstants = false;
entrypoint->cfaStructureClobberStateAtHead = StructuresAreWatched;
entrypoint->cfaStructureClobberStateAtTail = StructuresAreWatched;
if (m_graph.m_form == SSA) {
for (size_t i = 0; i < entrypoint->valuesAtHead.numberOfArguments(); ++i) {
entrypoint->valuesAtHead.argument(i).clear();
entrypoint->valuesAtTail.argument(i).clear();
}
} else {
const ArgumentsVector& arguments = m_graph.m_rootToArguments.find(entrypoint)->value;
for (size_t i = 0; i < entrypoint->valuesAtHead.numberOfArguments(); ++i) {
entrypoint->valuesAtTail.argument(i).clear();
FlushFormat format;
Node* node = arguments[i];
if (!node)
format = FlushedJSValue;
else {
ASSERT(node->op() == SetArgument);
format = node->variableAccessData()->flushFormat();
}
switch (format) {
case FlushedInt32:
entrypoint->valuesAtHead.argument(i).setType(SpecInt32Only);
break;
case FlushedBoolean:
entrypoint->valuesAtHead.argument(i).setType(SpecBoolean);
break;
case FlushedCell:
entrypoint->valuesAtHead.argument(i).setType(m_graph, SpecCellCheck);
break;
case FlushedJSValue:
entrypoint->valuesAtHead.argument(i).makeBytecodeTop();
break;
default:
DFG_CRASH(m_graph, nullptr, "Bad flush format for argument");
break;
}
}
}
for (size_t i = 0; i < entrypoint->valuesAtHead.numberOfLocals(); ++i) {
entrypoint->valuesAtHead.local(i).clear();
entrypoint->valuesAtTail.local(i).clear();
}
}
for (BasicBlock* block : m_graph.blocksInNaturalOrder()) {
if (m_graph.isRoot(block)) {
// We bootstrapped the CFG roots above.
continue;
}
ASSERT(block->isReachable);
block->cfaShouldRevisit = false;
block->cfaHasVisited = false;
block->cfaFoundConstants = false;
block->cfaStructureClobberStateAtHead = StructuresAreWatched;
block->cfaStructureClobberStateAtTail = StructuresAreWatched;
for (size_t i = 0; i < block->valuesAtHead.numberOfArguments(); ++i) {
block->valuesAtHead.argument(i).clear();
block->valuesAtTail.argument(i).clear();
}
for (size_t i = 0; i < block->valuesAtHead.numberOfLocals(); ++i) {
block->valuesAtHead.local(i).clear();
block->valuesAtTail.local(i).clear();
}
}
if (m_graph.m_form == SSA) {
for (BlockIndex blockIndex = 0; blockIndex < m_graph.numBlocks(); ++blockIndex) {
BasicBlock* block = m_graph.block(blockIndex);
if (!block)
continue;
setLiveValues(block->ssa->valuesAtHead, block->ssa->liveAtHead);
setLiveValues(block->ssa->valuesAtTail, block->ssa->liveAtTail);
}
}
}
bool InPlaceAbstractState::endBasicBlock()
{
ASSERT(m_block);
BasicBlock* block = m_block; // Save the block for successor merging.
block->cfaFoundConstants = m_foundConstants;
block->cfaDidFinish = m_isValid;
block->cfaBranchDirection = m_branchDirection;
if (!m_isValid) {
reset();
return false;
}
block->cfaStructureClobberStateAtTail = m_structureClobberState;
switch (m_graph.m_form) {
case ThreadedCPS: {
for (size_t argument = 0; argument < block->variablesAtTail.numberOfArguments(); ++argument) {
AbstractValue& destination = block->valuesAtTail.argument(argument);
mergeStateAtTail(destination, m_variables.argument(argument), block->variablesAtTail.argument(argument));
}
for (size_t local = 0; local < block->variablesAtTail.numberOfLocals(); ++local) {
AbstractValue& destination = block->valuesAtTail.local(local);
mergeStateAtTail(destination, m_variables.local(local), block->variablesAtTail.local(local));
}
break;
}
case SSA: {
for (size_t i = 0; i < block->valuesAtTail.size(); ++i)
block->valuesAtTail[i].merge(m_variables[i]);
for (NodeAbstractValuePair& valueAtTail : block->ssa->valuesAtTail) {
AbstractValue& valueAtNode = forNode(valueAtTail.node);
valueAtTail.value.merge(valueAtNode);
valueAtNode = valueAtTail.value;
}
break;
}
default:
RELEASE_ASSERT_NOT_REACHED();
}
reset();
return mergeToSuccessors(block);
}
void InPlaceAbstractState::reset()
{
m_block = 0;
m_isValid = false;
m_branchDirection = InvalidBranchDirection;
m_structureClobberState = StructuresAreWatched;
}
void InPlaceAbstractState::mergeStateAtTail(AbstractValue& destination, AbstractValue& inVariable, Node* node)
{
if (!node)
return;
const AbstractValue* source = nullptr;
switch (node->op()) {
case Phi:
case SetArgument:
case PhantomLocal:
case Flush:
// The block transfers the value from head to tail.
source = &inVariable;
break;
case GetLocal:
// The block refines the value with additional speculations.
source = &forNode(node);
break;
case SetLocal:
// The block sets the variable, and potentially refines it, both
// before and after setting it.
source = &forNode(node->child1());
if (node->variableAccessData()->flushFormat() == FlushedDouble)
RELEASE_ASSERT(!(source->m_type & ~SpecFullDouble));
break;
default:
RELEASE_ASSERT_NOT_REACHED();
break;
}
destination = *source;
}
bool InPlaceAbstractState::merge(BasicBlock* from, BasicBlock* to)
{
if (DFGInPlaceAbstractStateInternal::verbose)
dataLog(" Merging from ", pointerDump(from), " to ", pointerDump(to), "\n");
ASSERT(from->variablesAtTail.numberOfArguments() == to->variablesAtHead.numberOfArguments());
ASSERT(from->variablesAtTail.numberOfLocals() == to->variablesAtHead.numberOfLocals());
bool changed = false;
changed |= checkAndSet(
to->cfaStructureClobberStateAtHead,
DFG::merge(from->cfaStructureClobberStateAtTail, to->cfaStructureClobberStateAtHead));
switch (m_graph.m_form) {
case ThreadedCPS: {
for (size_t argument = 0; argument < from->variablesAtTail.numberOfArguments(); ++argument) {
AbstractValue& destination = to->valuesAtHead.argument(argument);
changed |= mergeVariableBetweenBlocks(destination, from->valuesAtTail.argument(argument), to->variablesAtHead.argument(argument), from->variablesAtTail.argument(argument));
}
for (size_t local = 0; local < from->variablesAtTail.numberOfLocals(); ++local) {
AbstractValue& destination = to->valuesAtHead.local(local);
changed |= mergeVariableBetweenBlocks(destination, from->valuesAtTail.local(local), to->variablesAtHead.local(local), from->variablesAtTail.local(local));
}
break;
}
case SSA: {
for (size_t i = from->valuesAtTail.size(); i--;)
changed |= to->valuesAtHead[i].merge(from->valuesAtTail[i]);
for (NodeAbstractValuePair& entry : to->ssa->valuesAtHead) {
NodeFlowProjection node = entry.node;
if (DFGInPlaceAbstractStateInternal::verbose)
dataLog(" Merging for ", node, ": from ", forNode(node), " to ", entry.value, "\n");
#ifndef NDEBUG
unsigned valueCountInFromBlock = 0;
for (NodeAbstractValuePair& fromBlockValueAtTail : from->ssa->valuesAtTail) {
if (fromBlockValueAtTail.node == node) {
ASSERT(fromBlockValueAtTail.value == forNode(node));
++valueCountInFromBlock;
}
}
ASSERT(valueCountInFromBlock == 1);
#endif
changed |= entry.value.merge(forNode(node));
if (DFGInPlaceAbstractStateInternal::verbose)
dataLog(" Result: ", entry.value, "\n");
}
break;
}
default:
RELEASE_ASSERT_NOT_REACHED();
break;
}
if (!to->cfaHasVisited)
changed = true;
if (DFGInPlaceAbstractStateInternal::verbose)
dataLog(" Will revisit: ", changed, "\n");
to->cfaShouldRevisit |= changed;
return changed;
}
inline bool InPlaceAbstractState::mergeToSuccessors(BasicBlock* basicBlock)
{
Node* terminal = basicBlock->terminal();
ASSERT(terminal->isTerminal());
switch (terminal->op()) {
case Jump: {
ASSERT(basicBlock->cfaBranchDirection == InvalidBranchDirection);
return merge(basicBlock, terminal->targetBlock());
}
case Branch: {
ASSERT(basicBlock->cfaBranchDirection != InvalidBranchDirection);
bool changed = false;
if (basicBlock->cfaBranchDirection != TakeFalse)
changed |= merge(basicBlock, terminal->branchData()->taken.block);
if (basicBlock->cfaBranchDirection != TakeTrue)
changed |= merge(basicBlock, terminal->branchData()->notTaken.block);
return changed;
}
case Switch: {
// FIXME: It would be cool to be sparse conditional for Switch's. Currently
// we're not. However I somehow doubt that this will ever be a big deal.
ASSERT(basicBlock->cfaBranchDirection == InvalidBranchDirection);
SwitchData* data = terminal->switchData();
bool changed = merge(basicBlock, data->fallThrough.block);
for (unsigned i = data->cases.size(); i--;)
changed |= merge(basicBlock, data->cases[i].target.block);
return changed;
}
case EntrySwitch: {
EntrySwitchData* data = terminal->entrySwitchData();
bool changed = false;
for (unsigned i = data->cases.size(); i--;)
changed |= merge(basicBlock, data->cases[i]);
return changed;
}
case Return:
case TailCall:
case DirectTailCall:
case TailCallVarargs:
case TailCallForwardVarargs:
case Unreachable:
case Throw:
case ThrowStaticError:
ASSERT(basicBlock->cfaBranchDirection == InvalidBranchDirection);
return false;
default:
RELEASE_ASSERT_NOT_REACHED();
return false;
}
}
inline bool InPlaceAbstractState::mergeVariableBetweenBlocks(AbstractValue& destination, AbstractValue& source, Node* destinationNode, Node* sourceNode)
{
if (!destinationNode)
return false;
ASSERT_UNUSED(sourceNode, sourceNode);
// FIXME: We could do some sparse conditional propagation here!
return destination.merge(source);
}
} } // namespace JSC::DFG
#endif // ENABLE(DFG_JIT)