[PATCH] D103131: support debug info for alias variable

[kamlesh kumar via Phabricator via cfe-commits]

kamleshbhalui updated this revision to Diff 347883.
kamleshbhalui retitled this revision from "support debug info for alias variable " to "support debug info for alias variable".
kamleshbhalui added a comment.

removed unnecessary code.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D103131/new/

https://reviews.llvm.org/D103131

Files:
  clang/lib/CodeGen/CGDebugInfo.cpp
  clang/lib/CodeGen/CGDebugInfo.h
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/test/CodeGen/debug-info-alias.c


Index: clang/test/CodeGen/debug-info-alias.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/debug-info-alias.c
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited -triple x86_64-linux-unknown %s -o - | FileCheck %s
+
+// CHECK: !DIImportedEntity(tag: DW_TAG_imported_declaration, scope:{{.*}}, entity: ![[VAR:[0-9]+]]
+// CHECK: ![[VAR]] = !DIGlobalVariable(name: "newname"
+
+int oldname = 1;
+extern int newname __attribute__((alias("oldname")));
Index: clang/lib/CodeGen/CodeGenModule.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenModule.cpp
+++ clang/lib/CodeGen/CodeGenModule.cpp
@@ -4922,6 +4922,12 @@
       setTLSMode(GA, *VD);
 
   SetCommonAttributes(GD, GA);
+
+  // Emit global alias debug information.
+  if (const auto *VD = dyn_cast<VarDecl>(D)) {
+    if (CGDebugInfo *DI = getModuleDebugInfo())
+      DI->EmitGlobalAlias(VD);
+  }
 }
 
 void CodeGenModule::emitIFuncDefinition(GlobalDecl GD) {
Index: clang/lib/CodeGen/CGDebugInfo.h
===================================================================
--- clang/lib/CodeGen/CGDebugInfo.h
+++ clang/lib/CodeGen/CGDebugInfo.h
@@ -493,6 +493,9 @@
   /// Emit information about an external variable.
   void EmitExternalVariable(llvm::GlobalVariable *GV, const VarDecl *Decl);
 
+  /// Emit information about global alias.
+  void EmitGlobalAlias(const VarDecl *Decl);
+
   /// Emit C++ using directive.
   void EmitUsingDirective(const UsingDirectiveDecl &UD);
 
Index: clang/lib/CodeGen/CGDebugInfo.cpp
===================================================================
--- clang/lib/CodeGen/CGDebugInfo.cpp
+++ clang/lib/CodeGen/CGDebugInfo.cpp
@@ -4945,6 +4945,19 @@
   Var->addDebugInfo(GVE);
 }
 
+void CGDebugInfo::EmitGlobalAlias(const VarDecl *D) {
+  if (!CGM.getCodeGenOpts().hasReducedDebugInfo())
+    return;
+
+  llvm::DIFile *Unit = getOrCreateFile(D->getLocation());
+  llvm::DIScope *DContext = getDeclContextDescriptor(D);
+  if (llvm::DINode *Target = getDeclarationOrDefinition(D)) {
+    auto Loc = D->getLocation();
+    DBuilder.createImportedDeclaration(DContext, Target, Unit,
+                                       getLineNumber(Loc));
+  }
+}
+
 llvm::DIScope *CGDebugInfo::getCurrentContextDescriptor(const Decl *D) {
   if (!LexicalBlockStack.empty())
     return LexicalBlockStack.back();


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