Calls and invokes with the new clang.arc.no_objc_arc_exceptions
metadata may still unwind, but only in ways that the ARC
optimizer doesn't need to consider. This permits more
aggressive optimization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150829 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/ObjCARC.cpp b/lib/Transforms/Scalar/ObjCARC.cpp
index 673e1a4..dd3e758 100644
--- a/lib/Transforms/Scalar/ObjCARC.cpp
+++ b/lib/Transforms/Scalar/ObjCARC.cpp
@@ -1655,6 +1655,10 @@
/// metadata.
unsigned CopyOnEscapeMDKind;
+ /// NoObjCARCExceptionsMDKind - The Metadata Kind for
+ /// clang.arc.no_objc_arc_exceptions metadata.
+ unsigned NoObjCARCExceptionsMDKind;
+
Constant *getRetainRVCallee(Module *M);
Constant *getAutoreleaseRVCallee(Module *M);
Constant *getReleaseCallee(Module *M);
@@ -2406,7 +2410,15 @@
bool SomeSuccHasSame = false;
bool AllSuccsHaveSame = true;
PtrState &S = MyStates.getPtrTopDownState(Arg);
- for (succ_const_iterator SI(TI), SE(TI, false); SI != SE; ++SI) {
+ succ_const_iterator SI(TI), SE(TI, false);
+
+ // If the terminator is an invoke marked with the
+ // clang.arc.no_objc_arc_exceptions metadata, the unwind edge can be
+ // ignored, for ARC purposes.
+ if (isa<InvokeInst>(TI) && TI->getMetadata(NoObjCARCExceptionsMDKind))
+ --SE;
+
+ for (; SI != SE; ++SI) {
PtrState &SuccS = BBStates[*SI].getPtrBottomUpState(Arg);
switch (SuccS.GetSeq()) {
case S_None:
@@ -2441,7 +2453,15 @@
bool SomeSuccHasSame = false;
bool AllSuccsHaveSame = true;
PtrState &S = MyStates.getPtrTopDownState(Arg);
- for (succ_const_iterator SI(TI), SE(TI, false); SI != SE; ++SI) {
+ succ_const_iterator SI(TI), SE(TI, false);
+
+ // If the terminator is an invoke marked with the
+ // clang.arc.no_objc_arc_exceptions metadata, the unwind edge can be
+ // ignored, for ARC purposes.
+ if (isa<InvokeInst>(TI) && TI->getMetadata(NoObjCARCExceptionsMDKind))
+ --SE;
+
+ for (; SI != SE; ++SI) {
PtrState &SuccS = BBStates[*SI].getPtrBottomUpState(Arg);
switch (SuccS.GetSeq()) {
case S_None: {
@@ -2486,7 +2506,13 @@
succ_const_iterator SI(TI), SE(TI, false);
if (SI == SE)
MyStates.SetAsExit();
- else
+ else {
+ // If the terminator is an invoke marked with the
+ // clang.arc.no_objc_arc_exceptions metadata, the unwind edge can be
+ // ignored, for ARC purposes.
+ if (isa<InvokeInst>(TI) && TI->getMetadata(NoObjCARCExceptionsMDKind))
+ --SE;
+
do {
const BasicBlock *Succ = *SI++;
if (Succ == BB)
@@ -2507,6 +2533,7 @@
}
break;
} while (SI != SE);
+ }
// Visit all the instructions, bottom-up.
for (BasicBlock::iterator I = BB->end(), E = BB->begin(); I != E; --I) {
@@ -2668,7 +2695,18 @@
MyStates.SetAsEntry();
else
do {
- const BasicBlock *Pred = *PI++;
+ unsigned OperandNo = PI.getOperandNo();
+ const Use &Us = PI.getUse();
+ ++PI;
+
+ // Skip invoke unwind edges on invoke instructions marked with
+ // clang.arc.no_objc_arc_exceptions.
+ if (const InvokeInst *II = dyn_cast<InvokeInst>(Us.getUser()))
+ if (OperandNo == II->getNumArgOperands() + 2 &&
+ II->getMetadata(NoObjCARCExceptionsMDKind))
+ continue;
+
+ const BasicBlock *Pred = cast<TerminatorInst>(Us.getUser())->getParent();
if (Pred == BB)
continue;
DenseMap<const BasicBlock *, BBState>::iterator I = BBStates.find(Pred);
@@ -2850,7 +2888,8 @@
OnStack.insert(EntryBB);
do {
dfs_next_succ:
- succ_iterator End = succ_end(SuccStack.back().first);
+ TerminatorInst *TI = cast<TerminatorInst>(&SuccStack.back().first->back());
+ succ_iterator End = succ_iterator(TI, true);
while (SuccStack.back().second != End) {
BasicBlock *BB = *SuccStack.back().second++;
if (Visited.insert(BB)) {
@@ -2871,7 +2910,7 @@
SmallVector<BasicBlock *, 4> Exits;
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
BasicBlock *BB = I;
- if (BB->getTerminator()->getNumSuccessors() == 0)
+ if (cast<TerminatorInst>(&BB->back())->getNumSuccessors() == 0)
Exits.push_back(BB);
}
@@ -3507,6 +3546,8 @@
M.getContext().getMDKindID("clang.imprecise_release");
CopyOnEscapeMDKind =
M.getContext().getMDKindID("clang.arc.copy_on_escape");
+ NoObjCARCExceptionsMDKind =
+ M.getContext().getMDKindID("clang.arc.no_objc_arc_exceptions");
// Intuitively, objc_retain and others are nocapture, however in practice
// they are not, because they return their argument value. And objc_release