[clang][DebugInfo] Attach DW_AT_const_value to static data-member definitions if available

Author: Michael137

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -5518,11 +5518,17 @@ void CGDebugInfo::EmitGlobalVariable(llvm::GlobalVariable *Var,
     }
     AppendAddressSpaceXDeref(AddressSpace, Expr);
 
+    llvm::DIExpression *E = nullptr;
+    if (Expr.empty()) {
+      if (auto const *InitVal = evaluateConstantInitializer(D))
+        E = createConstantValueExpression(D, *InitVal);
+    } else
+      E = DBuilder.createExpression(Expr);
+
     llvm::DINodeArray Annotations = CollectBTFDeclTagAnnotations(D);
     GVE = DBuilder.createGlobalVariableExpression(
         DContext, DeclName, LinkageName, Unit, LineNo, getOrCreateType(T, Unit),
-        Var->hasLocalLinkage(), true,
-        Expr.empty() ? nullptr : DBuilder.createExpression(Expr),
+        Var->hasLocalLinkage(), true, E,
         getOrCreateStaticDataMemberDeclarationOrNull(D), TemplateParameters,
         Align, Annotations);
     Var->addDebugInfo(GVE);

clang/test/CodeGenCXX/debug-info-static-inline-member.cpp

@@ -43,7 +43,7 @@ int main() {
 // CHECK:      @{{.*}}cexpr_struct_with_addr{{.*}} = 
 // CHECK-SAME    !dbg ![[EMPTY_GLOBAL:[0-9]+]]
 
-// CHECK:      !DIGlobalVariableExpression(var: ![[INT_VAR:[0-9]+]], expr: !DIExpression())
+// CHECK:      !DIGlobalVariableExpression(var: ![[INT_VAR:[0-9]+]], expr: !DIExpression(DW_OP_constu, 25, DW_OP_stack_value))
 // CHECK:      ![[INT_VAR]] = distinct !DIGlobalVariable(name: "cexpr_int_with_addr", linkageName:
 // CHECK-SAME:                isLocal: false, isDefinition: true, declaration: ![[INT_DECL:[0-9]+]])
 

clang/test/CodeGenCXX/inline-dllexport-member.cpp

@@ -7,7 +7,7 @@ struct __declspec(dllexport) s {
   static const unsigned int ui = 0;
 };
 
-// CHECK: [[UI]] = !DIGlobalVariableExpression(var: [[UIV:.*]], expr: !DIExpression())
+// CHECK: [[UI]] = !DIGlobalVariableExpression(var: [[UIV:.*]], expr: !DIExpression(DW_OP_constu, 0, DW_OP_stack_value))
 // CHECK: [[UIV]] = distinct !DIGlobalVariable(name: "ui", linkageName: "?ui@s@@2IB", scope: ![[SCOPE:[0-9]+]],
 // CHECK: ![[SCOPE]] = distinct !DICompileUnit(