[llvm-branch-commits] [clang] [clang][DebugInfo] Disable VTable debug info (#130255) on COFF platforms (PR #150938)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Tomohiro Kashiwada (kikairoya)

<details>
<summary>Changes</summary>

On COFF platform, d1b0cbff806b50d399826e79b9a53e4726c21302 generates a debug info linked with VTable even if that is dllimport-ed. That causes an access violation while performing runtime pseudo-relocation if the debug section is stripped.
For the release branch, we simply disable VTable debug info on COFF platform to avoid this problem.


---
Full diff: https://github.com/llvm/llvm-project/pull/150938.diff


2 Files Affected:

- (modified) clang/lib/CodeGen/CGDebugInfo.cpp (+2-1) 
- (modified) clang/test/CodeGenCXX/vtable-debug-info-inheritance-simple.cpp (+8-3) 


``````````diff
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 0dde045453e3a..ec28bd259e8e1 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -2645,7 +2645,8 @@ StringRef CGDebugInfo::getVTableName(const CXXRecordDecl *RD) {
 // existing information in the DWARF. The type is assumed to be 'void *'.
 void CGDebugInfo::emitVTableSymbol(llvm::GlobalVariable *VTable,
                                    const CXXRecordDecl *RD) {
-  if (!CGM.getTarget().getCXXABI().isItaniumFamily())
+  if (!CGM.getTarget().getCXXABI().isItaniumFamily() ||
+      CGM.getTarget().getTriple().isOSBinFormatCOFF())
     return;
 
   ASTContext &Context = CGM.getContext();
diff --git a/clang/test/CodeGenCXX/vtable-debug-info-inheritance-simple.cpp b/clang/test/CodeGenCXX/vtable-debug-info-inheritance-simple.cpp
index 249586f5991f1..b24ece1598327 100644
--- a/clang/test/CodeGenCXX/vtable-debug-info-inheritance-simple.cpp
+++ b/clang/test/CodeGenCXX/vtable-debug-info-inheritance-simple.cpp
@@ -1,5 +1,3 @@
-// REQUIRES: target={{x86_64.*-linux.*}}
-
 // Simple inheritance case:
 // For CBase and CDerived we check:
 // - Generation of their vtables (including attributes).
@@ -30,13 +28,20 @@ int main() {
   return 0;
 }
 
-// RUN: %clang --target=x86_64-linux -Xclang -disable-O0-optnone -Xclang -disable-llvm-passes -emit-llvm -S -g %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-linux -emit-llvm -mrelocation-model pic -pic-is-pie -debug-info-kind=limited -dwarf-version=5 -disable-O0-optnone -disable-llvm-passes %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-windows-gnu -emit-llvm -mrelocation-model pic -pic-is-pie -debug-info-kind=limited -dwarf-version=5 -disable-O0-optnone -disable-llvm-passes %s -o - | FileCheck %s --check-prefix=COFF
 
 // CHECK: $_ZTVN3NSP5CBaseE = comdat any
 // CHECK: $_ZTV8CDerived = comdat any
 
 // CHECK: @_ZTVN3NSP5CBaseE = linkonce_odr {{dso_local|hidden}} unnamed_addr constant {{.*}}, comdat, align 8, !dbg [[BASE_VTABLE_VAR:![0-9]*]]
 // CHECK: @_ZTV8CDerived = linkonce_odr {{dso_local|hidden}} unnamed_addr constant {{.*}}, comdat, align 8, !dbg [[DERIVED_VTABLE_VAR:![0-9]*]]
+// COFF: @_ZTVN3NSP5CBaseE = linkonce_odr {{dso_local|hidden}} unnamed_addr constant {{.*}}, comdat, align 8
+// COFF-NOT: !dbg
+// COFF-SAME: {{$}}
+// COFF: @_ZTV8CDerived = linkonce_odr {{dso_local|hidden}} unnamed_addr constant {{.*}}, comdat, align 8
+// COFF-NOT: !dbg
+// COFF-SAME: {{$}}
 
 // CHECK: [[BASE_VTABLE_VAR]] = !DIGlobalVariableExpression(var: [[BASE_VTABLE:![0-9]*]], expr: !DIExpression())
 // CHECK-NEXT: [[BASE_VTABLE]] = distinct !DIGlobalVariable(name: "_vtable$", linkageName: "_ZTVN3NSP5CBaseE"

``````````

</details>


https://github.com/llvm/llvm-project/pull/150938