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Imported Upstream version 6.4.0.137

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Former-commit-id: 943baa9f16a098c33e129777827f3a9d20da00d6
This commit is contained in:
Xamarin Public Jenkins (auto-signing)
2019-07-26 19:53:28 +00:00
parent e9207cf623
commit ef583813eb
2712 changed files with 74169 additions and 40587 deletions
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40
external/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp vendored
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@ -507,14 +507,28 @@ void DeadArgumentEliminationPass::SurveyFunction(const Function &F) {
// MaybeLive. Initialized to a list of RetCount empty lists.
RetUses MaybeLiveRetUses(RetCount);
for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
if (const ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator()))
bool HasMustTailCalls = false;
for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
if (const ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
if (RI->getNumOperands() != 0 && RI->getOperand(0)->getType()
!= F.getFunctionType()->getReturnType()) {
// We don't support old style multiple return values.
MarkLive(F);
return;
}
}
// If we have any returns of `musttail` results - the signature can't
// change
if (BB->getTerminatingMustTailCall() != nullptr)
HasMustTailCalls = true;
}
if (HasMustTailCalls) {
DEBUG(dbgs() << "DeadArgumentEliminationPass - " << F.getName()
<< " has musttail calls\n");
}
if (!F.hasLocalLinkage() && (!ShouldHackArguments || F.isIntrinsic())) {
MarkLive(F);
@ -526,6 +540,9 @@ void DeadArgumentEliminationPass::SurveyFunction(const Function &F) {
// Keep track of the number of live retvals, so we can skip checks once all
// of them turn out to be live.
unsigned NumLiveRetVals = 0;
bool HasMustTailCallers = false;
// Loop all uses of the function.
for (const Use &U : F.uses()) {
// If the function is PASSED IN as an argument, its address has been
@ -536,6 +553,11 @@ void DeadArgumentEliminationPass::SurveyFunction(const Function &F) {
return;
}
// The number of arguments for `musttail` call must match the number of
// arguments of the caller
if (CS.isMustTailCall())
HasMustTailCallers = true;
// If this use is anything other than a call site, the function is alive.
const Instruction *TheCall = CS.getInstruction();
if (!TheCall) { // Not a direct call site?
@ -580,6 +602,11 @@ void DeadArgumentEliminationPass::SurveyFunction(const Function &F) {
}
}
if (HasMustTailCallers) {
DEBUG(dbgs() << "DeadArgumentEliminationPass - " << F.getName()
<< " has musttail callers\n");
}
// Now we've inspected all callers, record the liveness of our return values.
for (unsigned i = 0; i != RetCount; ++i)
MarkValue(CreateRet(&F, i), RetValLiveness[i], MaybeLiveRetUses[i]);
@ -593,12 +620,19 @@ void DeadArgumentEliminationPass::SurveyFunction(const Function &F) {
for (Function::const_arg_iterator AI = F.arg_begin(),
E = F.arg_end(); AI != E; ++AI, ++i) {
Liveness Result;
if (F.getFunctionType()->isVarArg()) {
if (F.getFunctionType()->isVarArg() || HasMustTailCallers ||
HasMustTailCalls) {
// Variadic functions will already have a va_arg function expanded inside
// them, making them potentially very sensitive to ABI changes resulting
// from removing arguments entirely, so don't. For example AArch64 handles
// register and stack HFAs very differently, and this is reflected in the
// IR which has already been generated.
//
// `musttail` calls to this function restrict argument removal attempts.
// The signature of the caller must match the signature of the function.
//
// `musttail` calls in this function prevents us from changing its
// signature
Result = Live;
} else {
// See what the effect of this use is (recording any uses that cause