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SIL: add a utility function to check if a terminator exits a function… #1984

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Merged
merged 1 commit into from
Mar 31, 2016
Merged

SIL: add a utility function to check if a terminator exits a function… #1984

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6 changes: 6 additions & 0 deletions include/swift/SIL/SILInstruction.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3787,6 +3787,12 @@ class TermInst : public SILInstruction {

bool isBranch() const { return !getSuccessors().empty(); }

/// Returns true if this terminator exits the function.
bool isFunctionExiting() const {
return getKind() == ValueKind::ThrowInst ||
getKind() == ValueKind::ReturnInst;
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Can this be an exhaustive switch, so we cover any new instructions we add? Should Unreachable also be considered to exit the function?

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Can this be an exhaustive switch
Makes sense. I'll change it.

Should Unreachable also be considered to exit the function?
Not for the purposes where this function is used.

}

TermKind getTermKind() const { return ValueKindAsTermKind(getKind()); }
};

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8 changes: 4 additions & 4 deletions lib/SIL/SILVerifier.cpp
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Expand Up @@ -2975,11 +2975,11 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
"stack dealloc does not match most recent stack alloc");
stack.pop_back();
}
if (isa<ReturnInst>(&i) || isa<ThrowInst>(&i)) {
require(stack.empty(),
"return with stack allocs that haven't been deallocated");
}
if (auto term = dyn_cast<TermInst>(&i)) {
if (term->isFunctionExiting()) {
require(stack.empty(),
"return with stack allocs that haven't been deallocated");
}
for (auto &successor : term->getSuccessors()) {
SILBasicBlock *SuccBB = successor.getBB();
auto found = visitedBBs.find(SuccBB);
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4 changes: 2 additions & 2 deletions lib/SILOptimizer/IPO/EagerSpecializer.cpp
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Expand Up @@ -44,7 +44,7 @@ llvm::cl::opt<bool> EagerSpecializeFlag(
/// for new return or error values.
static bool isTrivialReturnBlock(SILBasicBlock *RetBB) {
auto *RetInst = RetBB->getTerminator();
assert(isa<ReturnInst>(RetInst) || isa<ThrowInst>(RetInst) &&
assert(RetInst->isFunctionExiting() &&
"expected a properly terminated return or throw block");

auto RetOperand = RetInst->getOperand(0);
Expand Down Expand Up @@ -87,7 +87,7 @@ static void addReturnValueImpl(SILBasicBlock *RetBB, SILBasicBlock *NewRetBB,
SILLocation Loc = F->getLocation();

auto *RetInst = RetBB->getTerminator();
assert(isa<ReturnInst>(RetInst) || isa<ThrowInst>(RetInst) &&
assert(RetInst->isFunctionExiting() &&
"expected a properly terminated return or throw block");
assert(RetInst->getOperand(0)->getType() == NewRetVal->getType() &&
"Mismatched return type");
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2 changes: 1 addition & 1 deletion lib/SILOptimizer/Mandatory/DefiniteInitialization.cpp
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Expand Up @@ -1874,7 +1874,7 @@ SILValue LifetimeChecker::handleConditionalInitAssign() {
// before the return.
for (auto &BB : TheMemory.getFunction()) {
auto *Term = BB.getTerminator();
if (isa<ReturnInst>(Term) || isa<ThrowInst>(Term)) {
if (Term->isFunctionExiting()) {
B.setInsertionPoint(Term);
B.createDeallocStack(Loc, ControlVariableBox);
}
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4 changes: 2 additions & 2 deletions lib/SILOptimizer/Mandatory/InOutDeshadowing.cpp
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Expand Up @@ -94,7 +94,7 @@ class StackSlotState {
// We need to see a store back to the inout on every exit path.
for (auto &bb : *F) {
auto term = bb.getTerminator();
if (isa<ReturnInst>(term) || isa<ThrowInst>(term)) {
if (term->isFunctionExiting()) {
DEBUG(llvm::dbgs() << " need load from stack slot on exit " << &bb
<< '\n');
ExitBBs.insert(&bb);
Expand Down Expand Up @@ -224,7 +224,7 @@ static void analyzeUseOfInOut(Operand *UI, StackSlotState &state) {
if (isa<UnreachableInst>(term))
return;

if (!isa<ReturnInst>(term) && !isa<ThrowInst>(term))
if (!term->isFunctionExiting())
// Any copy from the inout outside of an exit block fails the analysis.
// We don't need full flow-sensitive analysis for SILGen-ed code.
return state.setFailed("inout is stored outside of an exit block");
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4 changes: 2 additions & 2 deletions lib/SILOptimizer/SILCombiner/SILCombinerApplyVisitors.cpp
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Expand Up @@ -219,10 +219,10 @@ bool PartialApplyCombiner::allocateTemporaries() {

/// Emit dealloc_stack for all temporaries.
void PartialApplyCombiner::deallocateTemporaries() {
// Insert dealloc_stack instructions.
// Insert dealloc_stack instructions at all function exit points.
for (SILBasicBlock &BB : *PAI->getFunction()) {
TermInst *Term = BB.getTerminator();
if (!isa<ReturnInst>(Term) && !isa<ThrowInst>(Term))
if (!Term->isFunctionExiting())
continue;

for (auto Op : Tmps) {
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2 changes: 1 addition & 1 deletion lib/SILOptimizer/Transforms/AllocBoxToStack.cpp
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Expand Up @@ -837,7 +837,7 @@ class AllocBoxToStack : public SILFunctionTransform {

for (auto &BB : *getFunction()) {
auto *Term = BB.getTerminator();
if (isa<ReturnInst>(Term) || isa<ThrowInst>(Term))
if (Term->isFunctionExiting())
Returns.push_back(Term);

for (auto &I : BB)
Expand Down