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8ec9fd4839
I've taken the following steps to add unwinding support from inline assembly:
1) Add a new `unwind` "attribute" (like `sideeffect`) to the asm syntax:
```
invoke void asm sideeffect unwind "call thrower", "~{dirflag},~{fpsr},~{flags}"()
to label %exit unwind label %uexit
```
2.) Add Bitcode writing/reading support + LLVM-IR parsing.
3.) Emit EHLabels around inline assembly lowering (SelectionDAGBuilder + GlobalISel) when `InlineAsm::canThrow` is enabled.
4.) Tweak InstCombineCalls/InlineFunction pass to not mark inline assembly "calls" as nounwind.
5.) Add clang support by introducing a new clobber: "unwind", which lower to the `canThrow` being enabled.
6.) Don't allow unwinding callbr.
Reviewed By: Amanieu
Differential Revision: https://reviews.llvm.org/D95745
35 lines
896 B
C++
35 lines
896 B
C++
// RUN: %clang_cc1 -triple x86_64-unknown-linux -emit-llvm -DUNWIND -fcxx-exceptions -fexceptions -o - %s | FileCheck -check-prefixes CHECK,CHECK-UNWIND %s
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// RUN: %clang_cc1 -triple x86_64-unknown-linux -emit-llvm -fcxx-exceptions -fexceptions -o - %s | FileCheck -check-prefixes CHECK,CHECK-NO-UNWIND %s
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extern "C" void printf(const char *fmt, ...);
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struct DropBomb {
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bool defused = false;
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~DropBomb() {
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if (defused) {
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return;
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}
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printf("Boom!\n");
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}
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};
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extern "C" void trap() {
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throw "Trap";
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}
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// CHECK: define dso_local void @test()
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extern "C" void test() {
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DropBomb bomb;
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// CHECK-UNWIND: invoke void asm sideeffect unwind "call trap"
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// CHECK-NO-UNWIND: call void asm sideeffect "call trap"
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#ifdef UNWIND
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asm volatile("call trap" ::
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: "unwind");
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#else
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asm volatile("call trap" ::
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:);
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#endif
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bomb.defused = true;
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}
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