forked from OSchip/llvm-project
Don't crash on leaving nested __finally blocks through an EH edge.
The __finally emission block tries to be clever by removing unused continuation edges if there's an unconditional jump out of the __finally block. With exception edges, the EH continuation edge isn't always unused though and we'd crash in a few places. Just don't be clever. That makes the IR for __finally blocks a bit longer in some cases (hence small and behavior-preserving changes to existing tests), but it makes no difference in general and it fixes the last crash from PR22553. http://reviews.llvm.org/D7918 llvm-svn: 230697
This commit is contained in:
Nico Weber
parent
653773d004
commit
ff62a6a0b7
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@ -1684,8 +1684,7 @@ llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
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const char *RethrowName = Personality.CatchallRethrowFn;
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if (RethrowName != nullptr && !isCleanup) {
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EmitRuntimeCall(getCatchallRethrowFn(CGM, RethrowName),
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getExceptionFromSlot())
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->setDoesNotReturn();
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getExceptionFromSlot())->setDoesNotReturn();
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Builder.CreateUnreachable();
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Builder.restoreIP(SavedIP);
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return EHResumeBlock;
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@ -1943,23 +1942,17 @@ void CodeGenFunction::ExitSEHTryStmt(const SEHTryStmt &S, SEHFinallyInfo &FI) {
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Builder.SetInsertPoint(FI.FinallyBB);
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EmitStmt(Finally->getBlock());
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// If the finally block doesn't fall through, we don't need these blocks.
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if (!HaveInsertPoint()) {
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FI.ContBB->eraseFromParent();
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if (FI.ResumeBB)
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FI.ResumeBB->eraseFromParent();
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return;
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}
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if (FI.ResumeBB) {
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llvm::Value *IsEH = Builder.CreateLoad(getAbnormalTerminationSlot(),
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"abnormal.termination");
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IsEH = Builder.CreateICmpEQ(IsEH, llvm::ConstantInt::get(Int8Ty, 0));
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Builder.CreateCondBr(IsEH, FI.ContBB, FI.ResumeBB);
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} else {
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// There was nothing exceptional in the try body, so we only have normal
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// control flow.
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Builder.CreateBr(FI.ContBB);
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if (HaveInsertPoint()) {
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if (FI.ResumeBB) {
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llvm::Value *IsEH = Builder.CreateLoad(getAbnormalTerminationSlot(),
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"abnormal.termination");
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IsEH = Builder.CreateICmpEQ(IsEH, llvm::ConstantInt::get(Int8Ty, 0));
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Builder.CreateCondBr(IsEH, FI.ContBB, FI.ResumeBB);
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} else {
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// There was nothing exceptional in the try body, so we only have normal
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// control flow.
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Builder.CreateBr(FI.ContBB);
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}
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}
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Builder.restoreIP(SavedIP);
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@ -193,12 +193,99 @@ int nested___finally___finally() {
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// CHECK-NEXT: br label %[[finally:[^ ]*]]
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//
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// CHECK: [[finally]]
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// CHECK-NEXT: store i32 1, i32* %
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// CHECK-NEXT: store i8 0, i8* %
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// CHECK-NEXT: store i32 1, i32* %
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// CHECK-NEXT: store i32 1, i32* %
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// CHECK-NEXT: br label %[[cleanup:[^ ]*]]
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//
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// The finally's unreachable continuation block:
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// CHECK: store i32 0, i32* %
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// CHECK-NEXT: br label %[[cleanup]]
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//
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// CHECK: [[cleanup]]
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// CHECK-NEXT: store i8 0, i8* %
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// CHECK-NEXT: br label %[[outerfinally:[^ ]*]]
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//
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// CHECK: [[outerfinally]]
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// CHECK-NEXT: br label %[[finallycont:[^ ]*]]
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//
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// CHECK: [[finallycont]]
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// CHECK-NEXT: ret i32 1
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// CHECK-NEXT: %[[dest:[^ ]*]] = load i32* %
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// CHECK-NEXT: switch i32 %[[dest]]
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// CHECK-NEXT: i32 0, label %[[cleanupcont:[^ ]*]]
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//
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// CHECK: [[cleanupcont]]
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// CHECK-NEXT: store i32 0, i32* %
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// CHECK-NEXT: br label %[[return:[^ ]*]]
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//
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// CHECK: [[return]]
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// CHECK-NEXT: %[[reg:[^ ]*]] = load i32* %
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// CHECK-NEXT: ret i32 %[[reg]]
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int nested___finally___finally_with_eh_edge() {
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__try {
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__try {
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might_crash();
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} __finally {
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return 899;
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}
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} __finally {
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// Intentionally no return here.
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}
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return 912;
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}
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// CHECK-LABEL: define i32 @nested___finally___finally_with_eh_edge
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// CHECK: invoke void @might_crash() #3
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// CHECK-NEXT: to label %[[invokecont:[^ ]*]] unwind label %[[lpad:[^ ]*]]
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//
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// CHECK: [[invokecont]]
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// CHECK-NEXT: store i8 0, i8* %[[abnormal:[^ ]*]]
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// CHECK-NEXT: br label %[[finally:[^ ]*]]
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// CHECK: [[finally]]
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// CHECK-NEXT: store i32 899, i32* %
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// CHECK-NEXT: store i32 1, i32* %
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// CHECK-NEXT: br label %[[cleanup:[^ ]*]]
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//
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// The inner finally's unreachable continuation block:
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// CHECK: store i32 0, i32* %
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// CHECK-NEXT: br label %[[cleanup]]
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//
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// CHECK: [[cleanup]]
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// CHECK-NEXT: store i8 0, i8* %
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// CHECK-NEXT: br label %[[outerfinally:[^ ]*]]
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//
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// CHECK: [[outerfinally]]
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// CHECK-NEXT: %[[abnormallocal:[^ ]*]] = load i8* %[[abnormal]]
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// CHECK-NEXT: %[[reg:[^ ]*]] = icmp eq i8 %[[abnormallocal]], 0
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// CHECK-NEXT: br i1 %[[reg]], label %[[finallycont:[^ ]*]], label %[[finallyresume:[^ ]*]]
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//
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// CHECK: [[finallycont]]
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// CHECK-NEXT: %[[dest:[^ ]*]] = load i32* %
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// CHECK-NEXT: switch i32 %[[dest]]
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// CHECK-NEXT: i32 0, label %[[cleanupcont:[^ ]*]]
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//
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// CHECK: [[cleanupcont]]
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// CHECK-NEXT: store i32 912, i32* %
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// CHECK-NEXT: br label %[[return:[^ ]*]]
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//
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//
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// CHECK: [[lpad]]
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// CHECK-NEXT: landingpad
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// CHECK-NEXT: cleanup
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// CHECK: store i8 1, i8* %[[abnormal]]
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// CHECK: br label %[[finally]]
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//
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// The inner finally's unreachable resume block:
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// CHECK: store i8 1, i8* %[[abnormal]]
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// CHECK-NEXT: br label %[[outerfinally]]
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//
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// CHECK: [[finallyresume]]
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// CHECK-NEXT: br label %[[ehresume:[^ ]*]]
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//
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// CHECK: [[return]]
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// CHECK-NEXT: %[[reg:[^ ]*]] = load i32* %
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// CHECK-NEXT: ret i32 %[[reg]]
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//
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// The ehresume block, not reachable either.
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// CHECK: [[ehresume]]
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// CHECK: resume
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@ -162,6 +162,13 @@ int nested___except___finally() {
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// CHECK-NEXT: br label %[[tryleave:[^ ]*]]
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// CHECK-NOT: store i32 23
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// Unused __finally continuation block
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// CHECK: store i32 51, i32* %
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// CHECK-NEXT: br label %[[tryleave]]
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// CHECK: [[tryleave]]
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// CHECK-NEXT: br label %[[trycont:[^ ]*]]
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// CHECK: [[g1_lpad]]
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// CHECK: store i8 1, i8* %
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// CHECK-NEXT: br label %[[finally]]
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@ -171,14 +178,11 @@ int nested___except___finally() {
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// CHECK: br label %[[except:[^ ]*]]
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// CHECK: [[except]]
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// CHECK-NEXT: br label %[[trycont:[^ ]*]]
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// CHECK-NEXT: br label %[[trycont]]
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// CHECK: [[trycont]]
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// CHECK-NEXT: ret i32 1
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// CHECK: [[tryleave]]
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// CHECK-NEXT: br label %[[trycont]]
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int nested___except___except() {
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int myres = 0;
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__try {
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