/// Handle a rare case where the disintegrated nodes instructions
/// no longer dominate all their uses. Not sure if this is really nessasary
void StructurizeCFG::rebuildSSA() {
SSAUpdater Updater;
for (const auto &BB : ParentRegion->blocks())
for (BasicBlock::iterator II = BB->begin(), IE = BB->end();
II != IE; ++II) {
bool Initialized = false;
for (auto I = II->use_begin(), E = II->use_end(); I != E;) {
Use &U = *I++;
Instruction *User = cast<Instruction>(U.getUser());
if (User->getParent() == BB) {
continue;
} else if (PHINode *UserPN = dyn_cast<PHINode>(User)) {
if (UserPN->getIncomingBlock(U) == BB)
continue;
}
if (DT->dominates(II, User))
continue;
if (!Initialized) {
Value *Undef = UndefValue::get(II->getType());
Updater.Initialize(II->getType(), "");
Updater.AddAvailableValue(&Func->getEntryBlock(), Undef);
Updater.AddAvailableValue(BB, II);
Initialized = true;
}
Updater.RewriteUseAfterInsertions(U);
}
}
}
void WebAssemblyLowerEmscriptenEHSjLj::rebuildSSA(Function &F) {
DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
DT.recalculate(F); // CFG has been changed
SSAUpdater SSA;
for (BasicBlock &BB : F) {
for (Instruction &I : BB) {
for (auto UI = I.use_begin(), UE = I.use_end(); UI != UE;) {
Use &U = *UI;
++UI;
SSA.Initialize(I.getType(), I.getName());
SSA.AddAvailableValue(&BB, &I);
Instruction *User = cast<Instruction>(U.getUser());
if (User->getParent() == &BB)
continue;
if (PHINode *UserPN = dyn_cast<PHINode>(User))
if (UserPN->getIncomingBlock(U) == &BB)
continue;
if (DT.dominates(&I, User))
continue;
SSA.RewriteUseAfterInsertions(U);
}
}
}
}
/// Handle a rare case where the disintegrated nodes instructions
/// no longer dominate all their uses. Not sure if this is really nessasary
void StructurizeCFG::rebuildSSA() {
SSAUpdater Updater;
for (BasicBlock *BB : ParentRegion->blocks())
for (Instruction &I : *BB) {
bool Initialized = false;
// We may modify the use list as we iterate over it, so be careful to
// compute the next element in the use list at the top of the loop.
for (auto UI = I.use_begin(), E = I.use_end(); UI != E;) {
Use &U = *UI++;
Instruction *User = cast<Instruction>(U.getUser());
if (User->getParent() == BB) {
continue;
} else if (PHINode *UserPN = dyn_cast<PHINode>(User)) {
if (UserPN->getIncomingBlock(U) == BB)
continue;
}
if (DT->dominates(&I, User))
continue;
if (!Initialized) {
Value *Undef = UndefValue::get(I.getType());
Updater.Initialize(I.getType(), "");
Updater.AddAvailableValue(&Func->getEntryBlock(), Undef);
Updater.AddAvailableValue(BB, &I);
Initialized = true;
}
Updater.RewriteUseAfterInsertions(U);
}
}
}
/// Handle a rare case where the disintegrated nodes instructions
/// no longer dominate all their uses. Not sure if this is really nessasary
void StructurizeCFG::rebuildSSA() {
SSAUpdater Updater;
for (Region::block_iterator I = ParentRegion->block_begin(),
E = ParentRegion->block_end();
I != E; ++I) {
BasicBlock *BB = *I;
for (BasicBlock::iterator II = BB->begin(), IE = BB->end();
II != IE; ++II) {
bool Initialized = false;
for (Use *I = &II->use_begin().getUse(), *Next; I; I = Next) {
Next = I->getNext();
Instruction *User = cast<Instruction>(I->getUser());
if (User->getParent() == BB) {
continue;
} else if (PHINode *UserPN = dyn_cast<PHINode>(User)) {
if (UserPN->getIncomingBlock(*I) == BB)
continue;
}
if (DT->dominates(II, User))
continue;
if (!Initialized) {
Value *Undef = UndefValue::get(II->getType());
Updater.Initialize(II->getType(), "");
Updater.AddAvailableValue(&Func->getEntryBlock(), Undef);
Updater.AddAvailableValue(BB, II);
Initialized = true;
}
Updater.RewriteUseAfterInsertions(*I);
}
}
}
}
void WinEHPrepare::cloneCommonBlocks(Function &F) {
// We need to clone all blocks which belong to multiple funclets. Values are
// remapped throughout the funclet to propagate both the new instructions
// *and* the new basic blocks themselves.
for (auto &Funclets : FuncletBlocks) {
BasicBlock *FuncletPadBB = Funclets.first;
std::vector<BasicBlock *> &BlocksInFunclet = Funclets.second;
Value *FuncletToken;
if (FuncletPadBB == &F.getEntryBlock())
FuncletToken = ConstantTokenNone::get(F.getContext());
else
FuncletToken = FuncletPadBB->getFirstNonPHI();
std::vector<std::pair<BasicBlock *, BasicBlock *>> Orig2Clone;
ValueToValueMapTy VMap;
for (BasicBlock *BB : BlocksInFunclet) {
ColorVector &ColorsForBB = BlockColors[BB];
// We don't need to do anything if the block is monochromatic.
size_t NumColorsForBB = ColorsForBB.size();
if (NumColorsForBB == 1)
continue;
DEBUG_WITH_TYPE("winehprepare-coloring",
dbgs() << " Cloning block \'" << BB->getName()
<< "\' for funclet \'" << FuncletPadBB->getName()
<< "\'.\n");
// Create a new basic block and copy instructions into it!
BasicBlock *CBB =
CloneBasicBlock(BB, VMap, Twine(".for.", FuncletPadBB->getName()));
// Insert the clone immediately after the original to ensure determinism
// and to keep the same relative ordering of any funclet's blocks.
CBB->insertInto(&F, BB->getNextNode());
// Add basic block mapping.
VMap[BB] = CBB;
// Record delta operations that we need to perform to our color mappings.
Orig2Clone.emplace_back(BB, CBB);
}
// If nothing was cloned, we're done cloning in this funclet.
if (Orig2Clone.empty())
continue;
// Update our color mappings to reflect that one block has lost a color and
// another has gained a color.
for (auto &BBMapping : Orig2Clone) {
BasicBlock *OldBlock = BBMapping.first;
BasicBlock *NewBlock = BBMapping.second;
BlocksInFunclet.push_back(NewBlock);
ColorVector &NewColors = BlockColors[NewBlock];
assert(NewColors.empty() && "A new block should only have one color!");
NewColors.push_back(FuncletPadBB);
DEBUG_WITH_TYPE("winehprepare-coloring",
dbgs() << " Assigned color \'" << FuncletPadBB->getName()
<< "\' to block \'" << NewBlock->getName()
<< "\'.\n");
BlocksInFunclet.erase(
std::remove(BlocksInFunclet.begin(), BlocksInFunclet.end(), OldBlock),
BlocksInFunclet.end());
ColorVector &OldColors = BlockColors[OldBlock];
OldColors.erase(
std::remove(OldColors.begin(), OldColors.end(), FuncletPadBB),
OldColors.end());
DEBUG_WITH_TYPE("winehprepare-coloring",
dbgs() << " Removed color \'" << FuncletPadBB->getName()
<< "\' from block \'" << OldBlock->getName()
<< "\'.\n");
}
// Loop over all of the instructions in this funclet, fixing up operand
// references as we go. This uses VMap to do all the hard work.
for (BasicBlock *BB : BlocksInFunclet)
// Loop over all instructions, fixing each one as we find it...
for (Instruction &I : *BB)
RemapInstruction(&I, VMap,
RF_IgnoreMissingLocals | RF_NoModuleLevelChanges);
// Catchrets targeting cloned blocks need to be updated separately from
// the loop above because they are not in the current funclet.
SmallVector<CatchReturnInst *, 2> FixupCatchrets;
for (auto &BBMapping : Orig2Clone) {
BasicBlock *OldBlock = BBMapping.first;
BasicBlock *NewBlock = BBMapping.second;
FixupCatchrets.clear();
for (BasicBlock *Pred : predecessors(OldBlock))
if (auto *CatchRet = dyn_cast<CatchReturnInst>(Pred->getTerminator()))
if (CatchRet->getCatchSwitchParentPad() == FuncletToken)
FixupCatchrets.push_back(CatchRet);
for (CatchReturnInst *CatchRet : FixupCatchrets)
CatchRet->setSuccessor(NewBlock);
}
auto UpdatePHIOnClonedBlock = [&](PHINode *PN, bool IsForOldBlock) {
unsigned NumPreds = PN->getNumIncomingValues();
for (unsigned PredIdx = 0, PredEnd = NumPreds; PredIdx != PredEnd;
++PredIdx) {
BasicBlock *IncomingBlock = PN->getIncomingBlock(PredIdx);
bool EdgeTargetsFunclet;
if (auto *CRI =
dyn_cast<CatchReturnInst>(IncomingBlock->getTerminator())) {
EdgeTargetsFunclet = (CRI->getCatchSwitchParentPad() == FuncletToken);
} else {
ColorVector &IncomingColors = BlockColors[IncomingBlock];
assert(!IncomingColors.empty() && "Block not colored!");
assert((IncomingColors.size() == 1 ||
llvm::all_of(IncomingColors,
[&](BasicBlock *Color) {
return Color != FuncletPadBB;
})) &&
"Cloning should leave this funclet's blocks monochromatic");
EdgeTargetsFunclet = (IncomingColors.front() == FuncletPadBB);
}
if (IsForOldBlock != EdgeTargetsFunclet)
continue;
PN->removeIncomingValue(IncomingBlock, /*DeletePHIIfEmpty=*/false);
// Revisit the next entry.
--PredIdx;
--PredEnd;
}
};
for (auto &BBMapping : Orig2Clone) {
BasicBlock *OldBlock = BBMapping.first;
BasicBlock *NewBlock = BBMapping.second;
for (PHINode &OldPN : OldBlock->phis()) {
UpdatePHIOnClonedBlock(&OldPN, /*IsForOldBlock=*/true);
}
for (PHINode &NewPN : NewBlock->phis()) {
UpdatePHIOnClonedBlock(&NewPN, /*IsForOldBlock=*/false);
}
}
// Check to see if SuccBB has PHI nodes. If so, we need to add entries to
// the PHI nodes for NewBB now.
for (auto &BBMapping : Orig2Clone) {
BasicBlock *OldBlock = BBMapping.first;
BasicBlock *NewBlock = BBMapping.second;
for (BasicBlock *SuccBB : successors(NewBlock)) {
for (PHINode &SuccPN : SuccBB->phis()) {
// Ok, we have a PHI node. Figure out what the incoming value was for
// the OldBlock.
int OldBlockIdx = SuccPN.getBasicBlockIndex(OldBlock);
if (OldBlockIdx == -1)
break;
Value *IV = SuccPN.getIncomingValue(OldBlockIdx);
// Remap the value if necessary.
if (auto *Inst = dyn_cast<Instruction>(IV)) {
ValueToValueMapTy::iterator I = VMap.find(Inst);
if (I != VMap.end())
IV = I->second;
}
SuccPN.addIncoming(IV, NewBlock);
}
}
}
for (ValueToValueMapTy::value_type VT : VMap) {
// If there were values defined in BB that are used outside the funclet,
// then we now have to update all uses of the value to use either the
// original value, the cloned value, or some PHI derived value. This can
// require arbitrary PHI insertion, of which we are prepared to do, clean
// these up now.
SmallVector<Use *, 16> UsesToRename;
auto *OldI = dyn_cast<Instruction>(const_cast<Value *>(VT.first));
if (!OldI)
continue;
auto *NewI = cast<Instruction>(VT.second);
// Scan all uses of this instruction to see if it is used outside of its
// funclet, and if so, record them in UsesToRename.
for (Use &U : OldI->uses()) {
Instruction *UserI = cast<Instruction>(U.getUser());
BasicBlock *UserBB = UserI->getParent();
ColorVector &ColorsForUserBB = BlockColors[UserBB];
assert(!ColorsForUserBB.empty());
if (ColorsForUserBB.size() > 1 ||
*ColorsForUserBB.begin() != FuncletPadBB)
UsesToRename.push_back(&U);
}
// If there are no uses outside the block, we're done with this
// instruction.
if (UsesToRename.empty())
continue;
// We found a use of OldI outside of the funclet. Rename all uses of OldI
// that are outside its funclet to be uses of the appropriate PHI node
// etc.
SSAUpdater SSAUpdate;
SSAUpdate.Initialize(OldI->getType(), OldI->getName());
SSAUpdate.AddAvailableValue(OldI->getParent(), OldI);
SSAUpdate.AddAvailableValue(NewI->getParent(), NewI);
while (!UsesToRename.empty())
SSAUpdate.RewriteUseAfterInsertions(*UsesToRename.pop_back_val());
}
}
}
