MDefinition *
MIRGraph::parSlice() {
// Search the entry block to find a par slice instruction. If we do not
// find one, add one after the Start instruction.
//
// Note: the original design used a field in MIRGraph to cache the
// parSlice rather than searching for it again. However, this
// could become out of date due to DCE. Given that we do not
// generally have to search very far to find the par slice
// instruction if it exists, and that we don't look for it that
// often, I opted to simply eliminate the cache and search anew
// each time, so that it is that much easier to keep the IR
// coherent. - nmatsakis
MBasicBlock *entry = entryBlock();
JS_ASSERT(entry->info().executionMode() == ParallelExecution);
MInstruction *start = NULL;
for (MInstructionIterator ins(entry->begin()); ins != entry->end(); ins++) {
if (ins->isParSlice())
return *ins;
else if (ins->isStart())
start = *ins;
}
JS_ASSERT(start);
MParSlice *parSlice = new MParSlice();
entry->insertAfter(start, parSlice);
return parSlice;
}
MDefinition *
MIRGraph::forkJoinContext()
{
// Search the entry block to find a ForkJoinContext instruction. If we do
// not find one, add one after the Start instruction.
//
// Note: the original design used a field in MIRGraph to cache the
// forkJoinContext rather than searching for it again. However, this
// could become out of date due to DCE. Given that we do not generally
// have to search very far to find the ForkJoinContext instruction if it
// exists, and that we don't look for it that often, I opted to simply
// eliminate the cache and search anew each time, so that it is that much
// easier to keep the IR coherent. - nmatsakis
MBasicBlock *entry = entryBlock();
JS_ASSERT(entry->info().executionMode() == ParallelExecution);
MInstruction *start = nullptr;
for (MInstructionIterator ins(entry->begin()); ins != entry->end(); ins++) {
if (ins->isForkJoinContext())
return *ins;
else if (ins->isStart())
start = *ins;
}
JS_ASSERT(start);
MForkJoinContext *cx = MForkJoinContext::New(alloc());
entry->insertAfter(start, cx);
return cx;
}
