[PATCH] D84870: [DebugInfo] Fix to ctor homing to ignore classes with trivial ctors.

[Amy Huang via Phabricator via cfe-commits]

akhuang created this revision.
akhuang added a reviewer: dblaikie.
Herald added subscribers: cfe-commits, aprantl.
Herald added a project: clang.
akhuang requested review of this revision.

Previously ctor homing was omitting debug info for classes if they
have both trival and nontrivial constructors, but we should only omit debug
info if the class doesn't have any trivial constructors.

Also change to use completeUnusedClass so the debug info is added to the
retained types list.

bug: https://bugs.llvm.org/show_bug.cgi?id=46537


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D84870

Files:
  clang/lib/CodeGen/CGDebugInfo.cpp
  clang/test/CodeGenCXX/debug-info-limited-ctor.cpp


Index: clang/test/CodeGenCXX/debug-info-limited-ctor.cpp
===================================================================
--- clang/test/CodeGenCXX/debug-info-limited-ctor.cpp
+++ clang/test/CodeGenCXX/debug-info-limited-ctor.cpp
@@ -24,3 +24,9 @@
 struct E {
   constexpr E(){};
 } TestE;
+
+// CHECK-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: 
"F"{{.*}}DIFlagTypePassByValue
+struct F {
+  F() = default;
+  F(int) {}
+} TestF;
Index: clang/lib/CodeGen/CGDebugInfo.cpp
===================================================================
--- clang/lib/CodeGen/CGDebugInfo.cpp
+++ clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1705,14 +1705,13 @@
   // info is emitted.
   if (DebugKind == codegenoptions::DebugInfoConstructor)
     if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Method))
-      completeClass(CD->getParent());
+      completeUnusedClass(*CD->getParent());
 
   llvm::DINodeArray TParamsArray = CollectFunctionTemplateParams(Method, Unit);
   llvm::DISubprogram *SP = DBuilder.createMethod(
       RecordTy, MethodName, MethodLinkageName, MethodDefUnit, MethodLine,
       MethodTy, VIndex, ThisAdjustment, ContainingType, Flags, SPFlags,
       TParamsArray.get());
-
   SPCache[Method->getCanonicalDecl()].reset(SP);
 
   return SP;
@@ -2296,12 +2295,19 @@
   // In constructor debug mode, only emit debug info for a class when its
   // constructor is emitted. Skip this optimization if the class or any of
   // its methods are marked dllimport.
+  //
+  // This applies to classes that don't have any trivial constructors and have
+  // at least one constructor.
   if (DebugKind == codegenoptions::DebugInfoConstructor &&
       !CXXDecl->isLambda() && !CXXDecl->hasConstexprNonCopyMoveConstructor() &&
-      !isClassOrMethodDLLImport(CXXDecl))
+      !isClassOrMethodDLLImport(CXXDecl)) {
+    if (CXXDecl->ctors().empty())
+      return false;
     for (const auto *Ctor : CXXDecl->ctors())
-      if (Ctor->isUserProvided())
-        return true;
+      if (Ctor->isTrivial() && !Ctor->isCopyOrMoveConstructor())
+        return false;
+    return true;
+  }
 
   TemplateSpecializationKind Spec = TSK_Undeclared;
   if (const auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD))



Index: clang/test/CodeGenCXX/debug-info-limited-ctor.cpp
===================================================================
--- clang/test/CodeGenCXX/debug-info-limited-ctor.cpp
+++ clang/test/CodeGenCXX/debug-info-limited-ctor.cpp
@@ -24,3 +24,9 @@
 struct E {
   constexpr E(){};
 } TestE;
+
+// CHECK-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "F"{{.*}}DIFlagTypePassByValue
+struct F {
+  F() = default;
+  F(int) {}
+} TestF;
Index: clang/lib/CodeGen/CGDebugInfo.cpp
===================================================================
--- clang/lib/CodeGen/CGDebugInfo.cpp
+++ clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1705,14 +1705,13 @@
   // info is emitted.
   if (DebugKind == codegenoptions::DebugInfoConstructor)
     if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Method))
-      completeClass(CD->getParent());
+      completeUnusedClass(*CD->getParent());
 
   llvm::DINodeArray TParamsArray = CollectFunctionTemplateParams(Method, Unit);
   llvm::DISubprogram *SP = DBuilder.createMethod(
       RecordTy, MethodName, MethodLinkageName, MethodDefUnit, MethodLine,
       MethodTy, VIndex, ThisAdjustment, ContainingType, Flags, SPFlags,
       TParamsArray.get());
-
   SPCache[Method->getCanonicalDecl()].reset(SP);
 
   return SP;
@@ -2296,12 +2295,19 @@
   // In constructor debug mode, only emit debug info for a class when its
   // constructor is emitted. Skip this optimization if the class or any of
   // its methods are marked dllimport.
+  //
+  // This applies to classes that don't have any trivial constructors and have
+  // at least one constructor.
   if (DebugKind == codegenoptions::DebugInfoConstructor &&
       !CXXDecl->isLambda() && !CXXDecl->hasConstexprNonCopyMoveConstructor() &&
-      !isClassOrMethodDLLImport(CXXDecl))
+      !isClassOrMethodDLLImport(CXXDecl)) {
+    if (CXXDecl->ctors().empty())
+      return false;
     for (const auto *Ctor : CXXDecl->ctors())
-      if (Ctor->isUserProvided())
-        return true;
+      if (Ctor->isTrivial() && !Ctor->isCopyOrMoveConstructor())
+        return false;
+    return true;
+  }
 
   TemplateSpecializationKind Spec = TSK_Undeclared;
   if (const auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD))

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