/// Mapping from live pointers to a base-defining-value
DenseMap<llvm::Value *, llvm::Value *> PointerToBase;
- /// Any new values which were added to the IR during base pointer analysis
- /// for this safepoint
- DenseSet<llvm::Value *> NewInsertedDefs;
-
/// The *new* gc.statepoint instruction itself. This produces the token
/// that normal path gc.relocates and the gc.result are tied to.
Instruction *StatepointToken;
/// from. For gc objects, this is simply itself. On success, returns a value
/// which is the base pointer. (This is reliable and can be used for
/// relocation.) On failure, returns nullptr.
-static Value *findBasePointer(Value *I, DefiningValueMapTy &cache,
- DenseSet<llvm::Value *> &NewInsertedDefs) {
+static Value *findBasePointer(Value *I, DefiningValueMapTy &cache) {
Value *def = findBaseOrBDV(I, cache);
if (isKnownBaseResult(def)) {
std::distance(pred_begin(v->getParent()), pred_end(v->getParent()));
assert(num_preds > 0 && "how did we reach here");
PHINode *phi = PHINode::Create(v->getType(), num_preds, "base_phi", v);
- NewInsertedDefs.insert(phi);
// Add metadata marking this as a base value
auto *const_1 = ConstantInt::get(
Type::getInt32Ty(
UndefValue *undef = UndefValue::get(sel->getType());
SelectInst *basesel = SelectInst::Create(sel->getCondition(), undef,
undef, "base_select", sel);
- NewInsertedDefs.insert(basesel);
// Add metadata marking this as a base value
auto *const_1 = ConstantInt::get(
Type::getInt32Ty(
assert(states.count(base));
base = states[base].getBase();
assert(base != nullptr && "unknown PhiState!");
- assert(NewInsertedDefs.count(base) &&
- "should have already added this in a prev. iteration!");
}
// In essense this assert states: the only way two
if (base->getType() != basephi->getType()) {
base = new BitCastInst(base, basephi->getType(), "cast",
InBB->getTerminator());
- NewInsertedDefs.insert(base);
}
basephi->addIncoming(base, InBB);
}
// The cast is needed since base traversal may strip away bitcasts
if (base->getType() != basesel->getType()) {
base = new BitCastInst(base, basesel->getType(), "cast", basesel);
- NewInsertedDefs.insert(base);
}
basesel->setOperand(i, base);
}
static void
findBasePointers(const StatepointLiveSetTy &live,
DenseMap<llvm::Value *, llvm::Value *> &PointerToBase,
- DominatorTree *DT, DefiningValueMapTy &DVCache,
- DenseSet<llvm::Value *> &NewInsertedDefs) {
+ DominatorTree *DT, DefiningValueMapTy &DVCache) {
// For the naming of values inserted to be deterministic - which makes for
// much cleaner and more stable tests - we need to assign an order to the
// live values. DenseSets do not provide a deterministic order across runs.
Temp.insert(Temp.end(), live.begin(), live.end());
std::sort(Temp.begin(), Temp.end(), order_by_name);
for (Value *ptr : Temp) {
- Value *base = findBasePointer(ptr, DVCache, NewInsertedDefs);
+ Value *base = findBasePointer(ptr, DVCache);
assert(base && "failed to find base pointer");
PointerToBase[ptr] = base;
assert((!isa<Instruction>(base) || !isa<Instruction>(ptr) ||
const CallSite &CS,
PartiallyConstructedSafepointRecord &result) {
DenseMap<llvm::Value *, llvm::Value *> PointerToBase;
- DenseSet<llvm::Value *> NewInsertedDefs;
- findBasePointers(result.liveset, PointerToBase, &DT, DVCache,
- NewInsertedDefs);
+ findBasePointers(result.liveset, PointerToBase, &DT, DVCache);
if (PrintBasePointers) {
// Note: Need to print these in a stable order since this is checked in
}
result.PointerToBase = PointerToBase;
- result.NewInsertedDefs = NewInsertedDefs;
}
/// Given an updated version of the dataflow liveness results, update the
// One case which can arise is a phi node starting one of the successor blocks.
// We also need to be able to insert the gc.relocates only on the path which
// goes through the statepoint. We might need to split an edge to make this
-// possible.
-static BasicBlock *normalizeForInvokeSafepoint(BasicBlock *BB,
- BasicBlock *InvokeParent,
- Pass *P) {
+// possible.
+static BasicBlock *
+normalizeForInvokeSafepoint(BasicBlock *BB, BasicBlock *InvokeParent, Pass *P) {
DominatorTree *DT = nullptr;
if (auto *DTP = P->getAnalysisIfAvailable<DominatorTreeWrapperPass>())
DT = &DTP->getDomTree();
}
GCRelocateOperands relocateOperands(relocatedValue);
- Value *originalValue = const_cast<Value *>(relocateOperands.derivedPtr());
+ Value *originalValue =
+ const_cast<Value *>(relocateOperands.getDerivedPtr());
assert(allocaMap.count(originalValue));
Value *alloca = allocaMap[originalValue];
store->insertAfter(inst);
}
} else {
- assert((isa<Argument>(def) || isa<GlobalVariable>(def) ||
- isa<ConstantPointerNull>(def)) &&
- "Must be argument or global");
+ assert(isa<Argument>(def));
store->insertAfter(cast<Instruction>(alloca));
}
}
}
}
-static Function *getUseHolder(Module &M) {
- FunctionType *ftype =
- FunctionType::get(Type::getVoidTy(M.getContext()), true);
- Function *Func = cast<Function>(M.getOrInsertFunction("__tmp_use", ftype));
- return Func;
-}
-
/// Insert holders so that each Value is obviously live through the entire
-/// liftetime of the call.
+/// lifetime of the call.
static void insertUseHolderAfter(CallSite &CS, const ArrayRef<Value *> Values,
- SmallVectorImpl<CallInst *> &holders) {
+ SmallVectorImpl<CallInst *> &Holders) {
+ if (Values.empty())
+ // No values to hold live, might as well not insert the empty holder
+ return;
+
Module *M = CS.getInstruction()->getParent()->getParent()->getParent();
- Function *Func = getUseHolder(*M);
+ // Use a dummy vararg function to actually hold the values live
+ Function *Func = cast<Function>(M->getOrInsertFunction(
+ "__tmp_use", FunctionType::get(Type::getVoidTy(M->getContext()), true)));
if (CS.isCall()) {
// For call safepoints insert dummy calls right after safepoint
- BasicBlock::iterator next(CS.getInstruction());
- next++;
- CallInst *base_holder = CallInst::Create(Func, Values, "", next);
- holders.push_back(base_holder);
- } else if (CS.isInvoke()) {
- // For invoke safepooints insert dummy calls both in normal and
- // exceptional destination blocks
- InvokeInst *invoke = cast<InvokeInst>(CS.getInstruction());
- CallInst *normal_holder = CallInst::Create(
- Func, Values, "", invoke->getNormalDest()->getFirstInsertionPt());
- CallInst *unwind_holder = CallInst::Create(
- Func, Values, "", invoke->getUnwindDest()->getFirstInsertionPt());
- holders.push_back(normal_holder);
- holders.push_back(unwind_holder);
- } else
- llvm_unreachable("unsupported call type");
+ BasicBlock::iterator Next(CS.getInstruction());
+ Next++;
+ Holders.push_back(CallInst::Create(Func, Values, "", Next));
+ return;
+ }
+ // For invoke safepooints insert dummy calls both in normal and
+ // exceptional destination blocks
+ auto *II = cast<InvokeInst>(CS.getInstruction());
+ Holders.push_back(CallInst::Create(
+ Func, Values, "", II->getNormalDest()->getFirstInsertionPt()));
+ Holders.push_back(CallInst::Create(
+ Func, Values, "", II->getUnwindDest()->getFirstInsertionPt()));
}
static void findLiveReferences(
// When inserting gc.relocates for invokes, we need to be able to insert at
// the top of the successor blocks. See the comment on
// normalForInvokeSafepoint on exactly what is needed. Note that this step
- // may restructure the CFG.
- for (CallSite CS : toUpdate)
- if (CS.isInvoke()) {
- InvokeInst *invoke = cast<InvokeInst>(CS.getInstruction());
- normalizeForInvokeSafepoint(invoke->getNormalDest(),
- invoke->getParent(), P);
- normalizeForInvokeSafepoint(invoke->getUnwindDest(),
- invoke->getParent(), P);
- }
+ // may restructure the CFG.
+ for (CallSite CS : toUpdate) {
+ if (!CS.isInvoke())
+ continue;
+ InvokeInst *invoke = cast<InvokeInst>(CS.getInstruction());
+ normalizeForInvokeSafepoint(invoke->getNormalDest(), invoke->getParent(),
+ P);
+ normalizeForInvokeSafepoint(invoke->getUnwindDest(), invoke->getParent(),
+ P);
+ }
// A list of dummy calls added to the IR to keep various values obviously
// live in the IR. We'll remove all of these when done.
// gep a + 1
// safepoint 2
// br loop
- DenseSet<llvm::Value *> allInsertedDefs;
- for (size_t i = 0; i < records.size(); i++) {
- struct PartiallyConstructedSafepointRecord &info = records[i];
- allInsertedDefs.insert(info.NewInsertedDefs.begin(),
- info.NewInsertedDefs.end());
- }
-
// We insert some dummy calls after each safepoint to definitely hold live
// the base pointers which were identified for that safepoint. We'll then
// ask liveness for _every_ base inserted to see what is now live. Then we
// TODO: Consider using bitvectors for liveness, the set of potentially
// interesting values should be small and easy to pre-compute.
-/// Is this value a constant consisting of entirely null values?
-static bool isConstantNull(Value *V) {
- return isa<Constant>(V) && cast<Constant>(V)->isNullValue();
-}
-
/// Compute the live-in set for the location rbegin starting from
/// the live-out set of the basic block
static void computeLiveInValues(BasicBlock::reverse_iterator rbegin,
for (Value *V : I->operands()) {
assert(!isUnhandledGCPointerType(V->getType()) &&
"support for FCA unimplemented");
- if (isHandledGCPointerType(V->getType()) && !isConstantNull(V) &&
- !isa<UndefValue>(V)) {
- // The choice to exclude null and undef is arbitrary here. Reconsider?
+ if (isHandledGCPointerType(V->getType()) && !isa<Constant>(V)) {
+ // The choice to exclude all things constant here is slightly subtle.
+ // There are two idependent reasons:
+ // - We assume that things which are constant (from LLVM's definition)
+ // do not move at runtime. For example, the address of a global
+ // variable is fixed, even though it's contents may not be.
+ // - Second, we can't disallow arbitrary inttoptr constants even
+ // if the language frontend does. Optimization passes are free to
+ // locally exploit facts without respect to global reachability. This
+ // can create sections of code which are dynamically unreachable and
+ // contain just about anything. (see constants.ll in tests)
LiveTmp.insert(V);
}
}
Value *V = Phi->getIncomingValueForBlock(BB);
assert(!isUnhandledGCPointerType(V->getType()) &&
"support for FCA unimplemented");
- if (isHandledGCPointerType(V->getType()) && !isConstantNull(V) &&
- !isa<UndefValue>(V)) {
- // The choice to exclude null and undef is arbitrary here. Reconsider?
+ if (isHandledGCPointerType(V->getType()) && !isa<Constant>(V)) {
LiveTmp.insert(V);
}
}
projects / oota-llvm.git / blobdiff