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

2

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

3

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

17

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

17

strip if possible

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

17

ditto

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

3

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-uwtable.cpp

+// This test is added to provide test coverage for the uwtable attribute. It
+// aims to make sure that for an X86_64 output compiled with -fexceptions or
+//  -fno-exceptions, a uwtable attribute is emitted. However, for an AArch64
+//  output with -fexceptions a uwtable attribute is emitted, but with 
+// -fno-exceptions a uwtable attribute is not emitted.
+
+// 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 -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 -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 -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}
+// ARM64_UWTABLE: attributes #0 =
+
+int main() {
+    return 1;
+}

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

+; This test is added to provide test coverage for the 
+; .cfi_sections .debug_frame intrinsic. It aims to make sure that for a AArch64
+; output compiled with -fexceptions, no .cfi_sections .debug_frame is emitted.
+
+; RUN: llc --filetype=asm %s -o - | FileCheck %s
+; CHECK-NOT: .cfi_sections .debug_frame
+; CHECK: .cfi_startproc
+
+
+; ModuleID = 'test.cpp'
+source_filename = "test.cpp"
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-apple-macosx13.0.0"
+
+; Function Attrs: noinline norecurse nounwind optnone ssp uwtable(sync)
+define i32 @main() #0 !dbg !10 {
+  %1 = alloca i32, align 4
+  store i32 0, ptr %1, align 4
+  ret i32 1, !dbg !15
+}
+
+attributes #0 = { noinline norecurse nounwind optnone ssp uwtable(sync)}
+
+!llvm.module.flags = !{!0, !1, !2, !3, !4, !5, !6}
+!llvm.dbg.cu = !{!7}
+!llvm.ident = !{!9}
+
+!0 = !{i32 2, !"SDK Version", [2 x i32] [i32 14, i32 0]}
+!1 = !{i32 7, !"Dwarf Version", i32 4}
+!2 = !{i32 2, !"Debug Info Version", i32 3}
+!3 = !{i32 1, !"wchar_size", i32 4}
+!4 = !{i32 8, !"PIC Level", i32 2}
+!5 = !{i32 7, !"uwtable", i32 1}
+!6 = !{i32 7, !"frame-pointer", i32 1}
+!7 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !8, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None, sysroot: "/Applications/Xcode.app", sdk: "MacOSX.sdk")
+!8 = !DIFile(filename: "test.cpp", directory: "/Users/shubham/Development")
+!9 = !{!"clang"}
+!10 = distinct !DISubprogram(name: "main", scope: !8, file: !8, line: 1, type: !11, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !14)
+!11 = !DISubroutineType(types: !12)
+!12 = !{!13}
+!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!14 = !{}
+!15 = !DILocation(line: 2, column: 5, scope: !10)

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

+; This test is added to provide test coverage for the 
+; .cfi_sections .debug_frame intrinsic. It aims to make sure that for a AArch64
+; output compiled with -fno-exceptions, a .cfi_sections .debug_frame is emitted.
+
+; RUN: llc --filetype=asm %s -o - | FileCheck %s
+; CHECK: .cfi_sections .debug_frame
+
+; ModuleID = 'test.cpp'
+source_filename = "test.cpp"
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-apple-macosx13.0.0"
+
+; Function Attrs: noinline norecurse nounwind optnone ssp
+define i32 @main() #0 !dbg !9 {
+  %1 = alloca i32, align 4
+  store i32 0, ptr %1, align 4
+  ret i32 1, !dbg !14
+}
+
+attributes #0 = { noinline norecurse nounwind optnone ssp }
+
+!llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
+!llvm.dbg.cu = !{!6}
+!llvm.ident = !{!8}
+
+!0 = !{i32 2, !"SDK Version", [2 x i32] [i32 14, i32 0]}
+!1 = !{i32 7, !"Dwarf Version", i32 4}
+!2 = !{i32 2, !"Debug Info Version", i32 3}
+!3 = !{i32 1, !"wchar_size", i32 4}
+!4 = !{i32 8, !"PIC Level", i32 2}
+!5 = !{i32 7, !"frame-pointer", i32 1}
+!6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None, sysroot: "/Applications/Xcode.app", sdk: "MacOSX.sdk")
+!7 = !DIFile(filename: "test.cpp", directory: "/Users/shubham/Development")
+!8 = !{!"clang"}
+!9 = distinct !DISubprogram(name: "main", scope: !7, file: !7, line: 1, type: !10, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !13)
+!10 = !DISubroutineType(types: !11)
+!11 = !{!12}
+!12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!13 = !{}
+!14 = !DILocation(line: 2, column: 5, scope: !9)

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

+; This test is added to provide test coverage for the 
+; .cfi_sections .debug_frame intrinsic. It aims to make sure that for an X86_64
+; output compiled with -fexceptions, no .cfi_sections .debug_frame is emitted.
+
+; RUN: llc --filetype=asm %s -o - | FileCheck %s
+; CHECK-NOT: .cfi_sections .debug_frame
+; CHECK: .cfi_startproc
+
+; ModuleID = 'test.cpp'
+source_filename = "test.cpp"
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx13.0.0"
+
+; Function Attrs: noinline norecurse nounwind optnone ssp uwtable
+define i32 @main() #0 !dbg !10 {
+  %1 = alloca i32, align 4
+  store i32 0, ptr %1, align 4
+  ret i32 1, !dbg !15
+}
+
+attributes #0 = { noinline norecurse nounwind optnone ssp uwtable  }
+
+!llvm.module.flags = !{!0, !1, !2, !3, !4, !5, !6}
+!llvm.dbg.cu = !{!7}
+!llvm.ident = !{!9}
+
+!0 = !{i32 2, !"SDK Version", [2 x i32] [i32 14, i32 0]}
+!1 = !{i32 7, !"Dwarf Version", i32 4}
+!2 = !{i32 2, !"Debug Info Version", i32 3}
+!3 = !{i32 1, !"wchar_size", i32 4}
+!4 = !{i32 8, !"PIC Level", i32 2}
+!5 = !{i32 7, !"uwtable", i32 2}
+!6 = !{i32 7, !"frame-pointer", i32 2}
+!7 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !8, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None, sysroot: "/Applications/Xcode.app", sdk: "MacOSX.sdk")
+!8 = !DIFile(filename: "test.cpp", directory: "/Users/shubham/Development")
+!9 = !{!"clang"}
+!10 = distinct !DISubprogram(name: "main", scope: !8, file: !8, line: 1, type: !11, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !14)
+!11 = !DISubroutineType(types: !12)
+!12 = !{!13}
+!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!14 = !{}
+!15 = !DILocation(line: 2, column: 5, scope: !10)

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

+; This test is added to provide test coverage for the 
+; .cfi_sections .debug_frame intrinsic. It aims to make sure that for an X86_64
+; output compiled with -fno-exceptions, no .cfi_sections .debug_frame is 
+; emitted.
+
+; RUN: llc --filetype=asm %s -o - | FileCheck %s
+; CHECK-NOT: .cfi_sections .debug_frame
+; CHECK: .cfi_startproc
+
+; ModuleID = 'test.cpp'
+source_filename = "test.cpp"
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx13.0.0"
+
+; Function Attrs: noinline norecurse nounwind optnone ssp uwtable
+define i32 @main() #0 !dbg !10 {
+  %1 = alloca i32, align 4
+  store i32 0, ptr %1, align 4
+  ret i32 1, !dbg !15
+}
+
+attributes #0 = { noinline norecurse nounwind optnone ssp uwtable }
+
+!llvm.module.flags = !{!0, !1, !2, !3, !4, !5, !6}
+!llvm.dbg.cu = !{!7}
+!llvm.ident = !{!9}
+
+!0 = !{i32 2, !"SDK Version", [2 x i32] [i32 14, i32 0]}
+!1 = !{i32 7, !"Dwarf Version", i32 4}
+!2 = !{i32 2, !"Debug Info Version", i32 3}
+!3 = !{i32 1, !"wchar_size", i32 4}
+!4 = !{i32 8, !"PIC Level", i32 2}
+!5 = !{i32 7, !"uwtable", i32 2}
+!6 = !{i32 7, !"frame-pointer", i32 2}
+!7 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !8, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None, sysroot: "/Applications/Xcode.app", sdk: "MacOSX.sdk")
+!8 = !DIFile(filename: "test.cpp", directory: "/Users/shubham/Development")
+!9 = !{!"clang"}
+!10 = distinct !DISubprogram(name: "main", scope: !8, file: !8, line: 1, type: !11, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !14)
+!11 = !DISubroutineType(types: !12)
+!12 = !{!13}
+!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!14 = !{}
+!15 = !DILocation(line: 2, column: 5, scope: !10)