Add test to verify behavior of .cfi_sections .debug_frame intrinsic

[rastogishubham]

Summary

I noticed that there was some lacking test coverage for checking when the .cfi_sections .debug_frame intrinsic is emitted. I added this test to address this.

On x86_64 we can see that even with -fno-exceptions there is no .cfi_sections .debug_frame intrinsic emitted because there is an unwind table attribute.

On Arm64 we can see that with -fno-exceptions, there is no unwind table attribute, so the .cfi_sections .debug_frame intrinsic is emitted correctly.

Alternatively, with -fexceptions, both Arm64 and x86_64 emit an unwind table and therefore do not emit a .cfi_sections .debug_frame intrinsic

All this work was done in addition to https://reviews.llvm.org/D139663 patch.

[aprantl]

Clang tests should not depend on a target. The right thing to do here is to generate LLVM IR from the source code and then check in LLVM IR somewhere into llvm/test and compile that with llc. IF there is something in clang that needs to be tested then you can add a second test that does source -> IR -> FileCheck in Clang.

[rastogishubham]

Addressed review feedback by making some tests llc tests instead of the clang driver tests

[aprantl]

llvm/test/DebugInfo/AArch64/test-fexceptions-debug-frame.ll

1 ↗

(On Diff #514735)

Can you add a comment explaining what is being tested here?

2 ↗

(On Diff #514735)

Can you also add one positive CHECK as a sanity check? Otherwise this test passes even if the llc binary outputs nothing.

16 ↗

(On Diff #514735)

it's considered good practice to strip all the "string" attributes that arent' strictly needed from tests, so they are easier to maintain when these attributes change in the future.

llvm/test/DebugInfo/AArch64/test-fno-exceptions-debug-frame.ll

16 ↗

(On Diff #514735)

strip if possible

llvm/test/DebugInfo/X86/test-fexceptions-debug-frame.ll

16 ↗

(On Diff #514735)

ditto

llvm/test/DebugInfo/X86/test-fno-exceptions-debug-frame.ll

2 ↗

(On Diff #514735)

ditto

[rastogishubham]

Addressed review comments, mainly:

1. Added a description to explain what each test does

2. Added a CHECK in tests that just had a CHECK-NOT

3. Renamed test-cfi.cpp to test-uwtable.cpp

clang/test/Driver/test-cfi.cpp

+// RUN: %clang -g -fexceptions --target=x86_64-apple-darwin %s -S -emit-llvm -o - | FileCheck %s --check-prefix=X86_64_UWTABLE_EXCEPTIONS
+// X86_64_UWTABLE_EXCEPTIONS: attributes #0 = { {{.*}} uwtable
+// X86_64_UWTABLE_EXCEPTIONS: !{{[0-9]+}} = !{i32 7, !"uwtable", i32 2}
+
+// RUN: %clang -g -fexceptions --target=x86_64-apple-darwin %s -S -o - | FileCheck %s --check-prefix=X86_64_EXCEPTIONS
+// X86_64_EXCEPTIONS-NOT: .cfi_sections .debug_frame
+
+// RUN: %clang -g -fno-exceptions --target=x86_64-apple-darwin %s -S -emit-llvm -o - | FileCheck %s --check-prefix=X86_64_UWTABLE
+// X86_64_UWTABLE: attributes #0 = { {{.*}} uwtable
+// X86_64_UWTABLE: !{{[0-9]+}} = !{i32 7, !"uwtable", i32 2}
+
+// RUN: %clang -g -fno-exceptions --target=x86_64-apple-darwin %s -S -o - | FileCheck %s --check-prefix=X86_64
+// X86_64-NOT: .cfi_sections .debug_frame
+
+// RUN: %clang -g -fexceptions --target=arm64-apple-darwin %s -S -emit-llvm -o - | FileCheck %s --check-prefix=ARM64_UWTABLE_EXCEPTIONS
+// ARM64_UWTABLE_EXCEPTIONS: attributes #0 = { {{.*}} uwtable
+// ARM64_UWTABLE_EXCEPTIONS: !{{[0-9]+}} = !{i32 7, !"uwtable", i32 1}
+
+// RUN: %clang -g -fexceptions --target=arm64-apple-darwin %s -S -o - | FileCheck %s --check-prefix=ARM64_EXCEPTIONS
+// ARM64_EXCEPTIONS-NOT: .cfi_sections .debug_frame
+
+// RUN: %clang -g -fno-exceptions --target=arm64-apple-darwin %s -S -emit-llvm -o - | FileCheck %s --check-prefix=ARM64_UWTABLE
+// ARM64_UWTABLE-NOT: attributes #0 = { {{.*}} uwtable
+// ARM64_UWTABLE-NOT: !{{[0-9]+}} = !{i32 7, !"uwtable", i32 2}
+
+// RUN: %clang -g -fno-exceptions --target=arm64-apple-darwin %s -S -o - | FileCheck %s --check-prefix=ARM64
+// ARM64: .cfi_sections .debug_frame
+
+int main() {
+    return 1;
+}