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/*
* Copyright (C) 2017 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 "AirFixSpillsAfterTerminals.h"
#if ENABLE(B3_JIT)
#include "AirBlockInsertionSet.h"
#include "AirCode.h"
#include "AirInsertionSet.h"
namespace JSC { namespace B3 { namespace Air {
void fixSpillsAfterTerminals(Code& code)
{
// Because there may be terminals that produce values, IRC may
// want to spill those terminals. It'll happen to spill it after
// the terminal. If we left the graph in this state, it'd be invalid
// because a terminal must be the last instruction in a block.
// We fix that here.
BlockInsertionSet blockInsertionSet(code);
InsertionSet insertionSet(code);
for (BasicBlock* block : code) {
unsigned terminalIndex = block->size();
bool foundTerminal = false;
while (terminalIndex--) {
if (block->at(terminalIndex).isTerminal()) {
foundTerminal = true;
break;
}
}
ASSERT_UNUSED(foundTerminal, foundTerminal);
if (terminalIndex == block->size() - 1)
continue;
// There must be instructions after the terminal because it's not the last instruction.
ASSERT(terminalIndex < block->size() - 1);
Vector<Inst, 1> instsToMove;
for (unsigned i = terminalIndex + 1; i < block->size(); i++)
instsToMove.append(block->at(i));
RELEASE_ASSERT(instsToMove.size());
for (FrequentedBlock& frequentedSuccessor : block->successors()) {
BasicBlock* successor = frequentedSuccessor.block();
// If successor's only predecessor is block, we can plant the spill inside
// the successor. Otherwise, we must split the critical edge and create
// a new block for the spill.
if (successor->numPredecessors() == 1) {
insertionSet.insertInsts(0, instsToMove);
insertionSet.execute(successor);
} else {
BasicBlock* newBlock = blockInsertionSet.insertBefore(successor, successor->frequency());
for (const Inst& inst : instsToMove)
newBlock->appendInst(inst);
newBlock->appendInst(Inst(Jump, instsToMove.last().origin));
newBlock->successors().append(successor);
frequentedSuccessor.block() = newBlock;
}
}
block->resize(terminalIndex + 1);
}
if (blockInsertionSet.execute())
code.resetReachability();
}
} } } // namespace JSC::B3::Air
#endif // ENABLE(B3_JIT)
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