[clang][TypePrinter] Replace AppendScope with printNestedNameSpecifier #168534

Michael137 · 2025-11-18T13:32:28Z

In debug-info we soon have the need to print names using the full scope of the entity (see discussion in #159592). Particularly, when a structure is scoped inside a function, we'd like to emit the name as func()::foo. CGDebugInfo uses the TypePrinter to print type names into debug-info. However, TypePrinter stops (and ignores) DeclContexts that are functions. I.e., it would just print foo. Ideally it would behave the same way printNestedNameSpecifier does. The FIXME in

llvm-project/clang/lib/AST/TypePrinter.cpp

Lines 1520 to 1521 in 47c1aa4

    
           // FIXME: Consider replacing this with NamedDecl::printNestedNameSpecifier, 
        
           // which can also print names for function and method scopes.

motivated this patch.

See #168533 for how this will be used by CGDebugInfo. The plan is to introduce a new PrintingPolicy that prints anonymous entities using their full scope (including function/anonymous scopes) and the mangling number.

In debug-info we soon have the need to print names using the full scope of the entity (see discussion in llvm#159592). Particularly, when a structure is scoped inside a function, we'd like to emit the name as `func()::foo`. `CGDebugInfo` uses the `TypePrinter` to print type names into debug-info. However, `TypePrinter` stops (and ignores) `DeclContext`s that are functions. I.e., it would just print `foo`. Ideally it would behave the same way `printNestedNameSpecifier` does. The FIXME in https://github.com/llvm/llvm-project/blob/47c1aa4cef638c97b74f3afb7bed60e92bba1f90/clang/lib/AST/TypePrinter.cpp#L1520-L1521 motivated this patch. See llvm#168533 for how this will be used by `CGDebugInfo`. The plan is to introduce a new `PrintingPolicy` that prints anonymous entities using their full scope (including function/anonymous scopes) and the mangling number.

llvmbot · 2025-11-18T13:33:03Z

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-modules

Author: Michael Buch (Michael137)

Changes

In debug-info we soon have the need to print names using the full scope of the entity (see discussion in #159592). Particularly, when a structure is scoped inside a function, we'd like to emit the name as func()::foo. CGDebugInfo uses the TypePrinter to print type names into debug-info. However, TypePrinter stops (and ignores) DeclContexts that are functions. I.e., it would just print foo. Ideally it would behave the same way printNestedNameSpecifier does. The FIXME in

llvm-project/clang/lib/AST/TypePrinter.cpp

Lines 1520 to 1521 in 47c1aa4

    
           // FIXME: Consider replacing this with NamedDecl::printNestedNameSpecifier, 
        
           // which can also print names for function and method scopes.

motivated this patch.

See #168533 for how this will be used by CGDebugInfo. The plan is to introduce a new PrintingPolicy that prints anonymous entities using their full scope (including function/anonymous scopes) and the mangling number.

Full diff: https://github.com/llvm/llvm-project/pull/168534.diff

8 Files Affected:

(modified) clang/lib/AST/Decl.cpp (+3)
(modified) clang/lib/AST/TypePrinter.cpp (+6-61)
(modified) clang/test/ASTMerge/struct/test.c (+2-2)
(modified) clang/test/CXX/drs/cwg6xx.cpp (+1-1)
(modified) clang/test/Index/print-type.c (+1-1)
(modified) clang/test/Layout/ms-x86-alias-avoidance-padding.cpp (+2-2)
(modified) clang/test/Modules/compare-record.c (+2-1)
(modified) clang/test/SemaObjCXX/arc-0x.mm (+4-4)

diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 8579e51e45697..b771faa4581ec 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -1742,6 +1742,9 @@ void NamedDecl::printNestedNameSpecifier(raw_ostream &OS,
   // Collect named contexts.
   DeclarationName NameInScope = getDeclName();
   for (; Ctx; Ctx = Ctx->getParent()) {
+    if (P.Callbacks && P.Callbacks->isScopeVisible(Ctx))
+      continue;
+
     // Suppress anonymous namespace if requested.
     if (P.SuppressUnwrittenScope && isa<NamespaceDecl>(Ctx) &&
         cast<NamespaceDecl>(Ctx)->isAnonymousNamespace())
diff --git a/clang/lib/AST/TypePrinter.cpp b/clang/lib/AST/TypePrinter.cpp
index c18b2eafc722c..d2881d5ac518a 100644
--- a/clang/lib/AST/TypePrinter.cpp
+++ b/clang/lib/AST/TypePrinter.cpp
@@ -131,8 +131,6 @@ class TypePrinter {
 
   void printBefore(QualType T, raw_ostream &OS);
   void printAfter(QualType T, raw_ostream &OS);
-  void AppendScope(DeclContext *DC, raw_ostream &OS,
-                   DeclarationName NameInScope);
   void printTagType(const TagType *T, raw_ostream &OS);
   void printFunctionAfter(const FunctionType::ExtInfo &Info, raw_ostream &OS);
 #define ABSTRACT_TYPE(CLASS, PARENT)
@@ -1226,7 +1224,7 @@ void TypePrinter::printTypeSpec(NamedDecl *D, raw_ostream &OS) {
   // In C, this will always be empty except when the type
   // being printed is anonymous within other Record.
   if (!Policy.SuppressScope)
-    AppendScope(D->getDeclContext(), OS, D->getDeclName());
+    D->printNestedNameSpecifier(OS, Policy);
 
   IdentifierInfo *II = D->getIdentifier();
   OS << II->getName();
@@ -1240,7 +1238,7 @@ void TypePrinter::printUnresolvedUsingBefore(const UnresolvedUsingType *T,
     OS << ' ';
   auto *D = T->getDecl();
   if (Policy.FullyQualifiedName || T->isCanonicalUnqualified()) {
-    AppendScope(D->getDeclContext(), OS, D->getDeclName());
+    D->printNestedNameSpecifier(OS, Policy);
   } else {
     T->getQualifier().print(OS, Policy);
   }
@@ -1257,7 +1255,7 @@ void TypePrinter::printUsingBefore(const UsingType *T, raw_ostream &OS) {
     OS << ' ';
   auto *D = T->getDecl();
   if (Policy.FullyQualifiedName) {
-    AppendScope(D->getDeclContext(), OS, D->getDeclName());
+    D->printNestedNameSpecifier(OS, Policy);
   } else {
     T->getQualifier().print(OS, Policy);
   }
@@ -1273,7 +1271,7 @@ void TypePrinter::printTypedefBefore(const TypedefType *T, raw_ostream &OS) {
     OS << ' ';
   auto *D = T->getDecl();
   if (Policy.FullyQualifiedName) {
-    AppendScope(D->getDeclContext(), OS, D->getDeclName());
+    D->printNestedNameSpecifier(OS, Policy);
   } else {
     T->getQualifier().print(OS, Policy);
   }
@@ -1511,59 +1509,6 @@ void TypePrinter::printPredefinedSugarBefore(const PredefinedSugarType *T,
 void TypePrinter::printPredefinedSugarAfter(const PredefinedSugarType *T,
                                             raw_ostream &OS) {}
 
-/// Appends the given scope to the end of a string.
-void TypePrinter::AppendScope(DeclContext *DC, raw_ostream &OS,
-                              DeclarationName NameInScope) {
-  if (DC->isTranslationUnit())
-    return;
-
-  // FIXME: Consider replacing this with NamedDecl::printNestedNameSpecifier,
-  // which can also print names for function and method scopes.
-  if (DC->isFunctionOrMethod())
-    return;
-
-  if (Policy.Callbacks && Policy.Callbacks->isScopeVisible(DC))
-    return;
-
-  if (const auto *NS = dyn_cast<NamespaceDecl>(DC)) {
-    if (Policy.SuppressUnwrittenScope && NS->isAnonymousNamespace())
-      return AppendScope(DC->getParent(), OS, NameInScope);
-
-    // Only suppress an inline namespace if the name has the same lookup
-    // results in the enclosing namespace.
-    if (Policy.SuppressInlineNamespace !=
-            PrintingPolicy::SuppressInlineNamespaceMode::None &&
-        NS->isInline() && NameInScope &&
-        NS->isRedundantInlineQualifierFor(NameInScope))
-      return AppendScope(DC->getParent(), OS, NameInScope);
-
-    AppendScope(DC->getParent(), OS, NS->getDeclName());
-    if (NS->getIdentifier())
-      OS << NS->getName() << "::";
-    else
-      OS << "(anonymous namespace)::";
-  } else if (const auto *Spec = dyn_cast<ClassTemplateSpecializationDecl>(DC)) {
-    AppendScope(DC->getParent(), OS, Spec->getDeclName());
-    IncludeStrongLifetimeRAII Strong(Policy);
-    OS << Spec->getIdentifier()->getName();
-    const TemplateArgumentList &TemplateArgs = Spec->getTemplateArgs();
-    printTemplateArgumentList(
-        OS, TemplateArgs.asArray(), Policy,
-        Spec->getSpecializedTemplate()->getTemplateParameters());
-    OS << "::";
-  } else if (const auto *Tag = dyn_cast<TagDecl>(DC)) {
-    AppendScope(DC->getParent(), OS, Tag->getDeclName());
-    if (TypedefNameDecl *Typedef = Tag->getTypedefNameForAnonDecl())
-      OS << Typedef->getIdentifier()->getName() << "::";
-    else if (Tag->getIdentifier())
-      OS << Tag->getIdentifier()->getName() << "::";
-    else
-      return;
-  } else {
-    AppendScope(DC->getParent(), OS, NameInScope);
-  }
-}
-
 void TypePrinter::printTagType(const TagType *T, raw_ostream &OS) {
   TagDecl *D = T->getDecl();
 
@@ -1593,7 +1538,7 @@ void TypePrinter::printTagType(const TagType *T, raw_ostream &OS) {
     // Compute the full nested-name-specifier for this type.
     // In C, this will always be empty except when the type
     // being printed is anonymous within other Record.
-    AppendScope(D->getDeclContext(), OS, D->getDeclName());
+    D->printNestedNameSpecifier(OS, Policy);
   }
 
   if (const IdentifierInfo *II = D->getIdentifier())
@@ -1809,7 +1754,7 @@ void TypePrinter::printTemplateId(const TemplateSpecializationType *T,
   // FIXME: Null TD never exercised in test suite.
   if (FullyQualify && TD) {
     if (!Policy.SuppressScope)
-      AppendScope(TD->getDeclContext(), OS, TD->getDeclName());
+      TD->printNestedNameSpecifier(OS, Policy);
 
     OS << TD->getName();
   } else {
diff --git a/clang/test/ASTMerge/struct/test.c b/clang/test/ASTMerge/struct/test.c
index 10ea753b142bd..d11234472ef29 100644
--- a/clang/test/ASTMerge/struct/test.c
+++ b/clang/test/ASTMerge/struct/test.c
@@ -44,10 +44,10 @@
 // CHECK: struct2.c:72:7: note: field 'i' has type 'int' here
 // CHECK: struct2.c:76:5: warning: external variable 'x13' declared with incompatible types in different translation units ('S13' vs. 'S13')
 // CHECK: struct1.c:79:5: note: declared here with type 'S13'
-// CHECK: struct1.c:130:7: warning: type 'struct DeepUnnamedError::(unnamed at [[PATH_TO_INPUTS:.+]]struct1.c:130:7)' has incompatible definitions in different translation units
+// CHECK: struct1.c:130:7: warning: type 'struct DeepUnnamedError::(anonymous union)::(anonymous union)::(unnamed at [[PATH_TO_INPUTS:.+]]struct1.c:130:7)' has incompatible definitions in different translation units
 // CHECK: struct1.c:131:14: note: field 'i' has type 'long' here
 // CHECK: struct2.c:128:15: note: field 'i' has type 'float' here
-// CHECK: struct1.c:129:5: warning: type 'union DeepUnnamedError::(unnamed at [[PATH_TO_INPUTS]]struct1.c:129:5)' has incompatible definitions in different translation units
+// CHECK: struct1.c:129:5: warning: type 'union DeepUnnamedError::(anonymous union)::(unnamed at [[PATH_TO_INPUTS]]struct1.c:129:5)' has incompatible definitions in different translation units
 // CHECK: struct1.c:132:9: note: field 'S' has type 'struct (unnamed struct at [[PATH_TO_INPUTS]]struct1.c:130:7)' here
 // CHECK: struct2.c:129:9: note: field 'S' has type 'struct (unnamed struct at [[PATH_TO_INPUTS]]struct2.c:127:7)' here
 // CHECK: struct2.c:138:3: warning: external variable 'x16' declared with incompatible types in different translation units ('struct DeepUnnamedError' vs. 'struct DeepUnnamedError')
diff --git a/clang/test/CXX/drs/cwg6xx.cpp b/clang/test/CXX/drs/cwg6xx.cpp
index 11eb0bf3a27b2..8eac049211193 100644
--- a/clang/test/CXX/drs/cwg6xx.cpp
+++ b/clang/test/CXX/drs/cwg6xx.cpp
@@ -1241,7 +1241,7 @@ namespace cwg686 { // cwg686: 3.0
 #endif
     struct N {
       operator struct O{}(){};
-      // expected-error@-1 {{'N::O' cannot be defined in a type specifier}}
+      // expected-error@-1 {{'cwg686::f()::N::O' cannot be defined in a type specifier}}
     };
     try {}
     catch (struct P *) {}
diff --git a/clang/test/Index/print-type.c b/clang/test/Index/print-type.c
index d30f4bed246c5..9fb85f8da4e66 100644
--- a/clang/test/Index/print-type.c
+++ b/clang/test/Index/print-type.c
@@ -71,7 +71,7 @@ _Atomic(unsigned long) aul;
 // CHECK: TypeRef=struct Struct:16:8 [type=struct Struct] [typekind=Record] [isPOD=1]
 // CHECK: StructDecl=struct (unnamed at {{.*}}):18:1 (Definition) [type=struct (unnamed at {{.*}}print-type.c:18:1)] [typekind=Record] [isPOD=1] [nbFields=2] [isAnon=1] [isAnonRecDecl=0]
 // CHECK: StructDecl=struct (unnamed at {{.*}}):23:1 (Definition) [type=struct (unnamed at {{.*}}print-type.c:23:1)] [typekind=Record] [isPOD=1] [nbFields=1] [isAnon=1] [isAnonRecDecl=0]
-// CHECK: StructDecl=struct (anonymous at {{.*}}):24:3 (Definition) [type=struct (anonymous at {{.*}}print-type.c:24:3)] [typekind=Record] [isPOD=1] [nbFields=2] [isAnon=1] [isAnonRecDecl=1]
+// CHECK: StructDecl=struct (anonymous at {{.*}}):24:3 (Definition) [type=struct (anonymous struct)::(anonymous at {{.*}}print-type.c:24:3)] [typekind=Record] [isPOD=1] [nbFields=2] [isAnon=1] [isAnonRecDecl=1]
 // CHECK: FieldDecl=x:25:17 (Definition) [type=_Atomic(int)] [typekind=Atomic] [valuetype=int] [valuetypekind=Int] [isPOD=0] [isAnonRecDecl=0]
 // CHECK: FieldDecl=y:26:9 (Definition) [type=int] [typekind=Int] [isPOD=1] [isAnonRecDecl=0]
 // CHECK: StructDecl=struct (unnamed at {{.*}}):30:10 (Definition) [type=struct (unnamed at {{.*}}print-type.c:30:10)] [typekind=Record] [isPOD=1] [nbFields=2] [isAnon=1] [isAnonRecDecl=0]
diff --git a/clang/test/Layout/ms-x86-alias-avoidance-padding.cpp b/clang/test/Layout/ms-x86-alias-avoidance-padding.cpp
index 678537bb514f5..bc6a56ef37538 100644
--- a/clang/test/Layout/ms-x86-alias-avoidance-padding.cpp
+++ b/clang/test/Layout/ms-x86-alias-avoidance-padding.cpp
@@ -49,7 +49,7 @@ struct AT3 : AT2, AT1 {
 // CHECK-NEXT:    0 |   struct AT2 (base)
 // CHECK-NEXT:    0 |     struct AT0 t
 // CHECK-NEXT:    0 |       union AT0::(unnamed at {{.*}} x
-// CHECK-NEXT:    0 |         struct AT0::(unnamed at {{.*}} y
+// CHECK-NEXT:    0 |         struct AT0::(anonymous union)::(unnamed at {{.*}} y
 // CHECK-NEXT:    0 |           int a
 // CHECK-NEXT:    4 |           struct AT t (empty)
 // CHECK:         0 |         int b
@@ -66,7 +66,7 @@ struct AT3 : AT2, AT1 {
 // CHECK-X64-NEXT:    0 |   struct AT2 (base)
 // CHECK-X64-NEXT:    0 |     struct AT0 t
 // CHECK-X64-NEXT:    0 |       union AT0::(unnamed at {{.*}} x
-// CHECK-X64-NEXT:    0 |         struct AT0::(unnamed at {{.*}} y
+// CHECK-X64-NEXT:    0 |         struct AT0::(anonymous union)::(unnamed at {{.*}} y
 // CHECK-X64-NEXT:    0 |           int a
 // CHECK-X64-NEXT:    4 |           struct AT t (empty)
 // CHECK-X64:         0 |         int b
diff --git a/clang/test/Modules/compare-record.c b/clang/test/Modules/compare-record.c
index ef4a3a5b0e90d..97caabd55fe33 100644
--- a/clang/test/Modules/compare-record.c
+++ b/clang/test/Modules/compare-record.c
@@ -496,6 +496,7 @@ struct CompareAnonymousNestedStruct compareAnonymousNestedStruct;
 // [email protected]:* {{declaration of 'anonymousNestedStructField' does not match}}
 #elif defined(CASE3)
 struct CompareDeeplyNestedAnonymousUnionsAndStructs compareDeeplyNested;
-// [email protected]:* {{'CompareDeeplyNestedAnonymousUnionsAndStructs::(anonymous union)::(anonymous union)::(anonymous struct)::z' from module 'Second' is not present in definition of 'struct CompareDeeplyNestedAnonymousUnionsAndStructs::(anonymous at {{.*}})' in module 'First.Hidden'}}
+// [email protected]:* {{'CompareDeeplyNestedAnonymousUnionsAndStructs::(anonymous union)::(anonymous union)::(anonymous struct)::z' from module 'Second' is not present in definition of 'struct CompareDeeplyNestedAnonymousUnionsAndStructs::(anonymous union)::(anonymous union)::(anonymous at {{.*}})' in module 'First.Hidden'}}
+
 // [email protected]:* {{declaration of 'z' does not match}}
 #endif
diff --git a/clang/test/SemaObjCXX/arc-0x.mm b/clang/test/SemaObjCXX/arc-0x.mm
index bcaa5da6b9283..a7418eceb244b 100644
--- a/clang/test/SemaObjCXX/arc-0x.mm
+++ b/clang/test/SemaObjCXX/arc-0x.mm
@@ -162,7 +162,7 @@ void test() {
 
   struct S1 {
     union {
-      union { // expected-note-re {{copy constructor of 'S1' is implicitly deleted because field 'test_union::S1::(anonymous union at {{.*}})' has a deleted copy constructor}} expected-note-re {{copy assignment operator of 'S1' is implicitly deleted because field 'test_union::S1::(anonymous union at {{.*}})' has a deleted copy assignment operator}} expected-note-re 4 {{'S1' is implicitly deleted because field 'test_union::S1::(anonymous union at {{.*}})' has a deleted}}
+      union { // expected-note-re {{copy constructor of 'S1' is implicitly deleted because field 'test_union::S1::(anonymous union)::(anonymous union at {{.*}})' has a deleted copy constructor}} expected-note-re {{copy assignment operator of 'S1' is implicitly deleted because field 'test_union::S1::(anonymous union)::(anonymous union at {{.*}})' has a deleted copy assignment operator}} expected-note-re 4 {{'S1' is implicitly deleted because field 'test_union::S1::(anonymous union)::(anonymous union at {{.*}})' has a deleted}}
         id f0; // expected-note-re 2 {{{{.*}} of '(anonymous union at {{.*}}' is implicitly deleted because variant field 'f0' is an ObjC pointer}}
         char f1;
       };
@@ -173,7 +173,7 @@ void test() {
   struct S2 {
     union {
       // FIXME: the note should say 'f0' is causing the special functions to be deleted.
-      struct { // expected-note-re 6 {{'S2' is implicitly deleted because variant field 'test_union::S2::(anonymous struct at {{.*}})' has a non-trivial}}
+      struct { // expected-note-re 6 {{'S2' is implicitly deleted because variant field 'test_union::S2::(anonymous union)::(anonymous struct at {{.*}})' has a non-trivial}}
         id f0;
         int f1;
       };
@@ -195,8 +195,8 @@ void test() {
   };
 
   static union { // expected-error {{call to implicitly-deleted default constructor of}}
-    union { // expected-note-re {{default constructor of '(unnamed union at {{.*}}' is implicitly deleted because field 'test_union::(anonymous union at {{.*}})' has a deleted default constructor}}
-      union { // expected-note-re {{default constructor of '(anonymous union at {{.*}}' is implicitly deleted because field 'test_union::(anonymous union at {{.*}})' has a deleted default constructor}}
+    union { // expected-note-re {{default constructor of '(unnamed union at {{.*}}' is implicitly deleted because field 'test_union::(anonymous union)::(anonymous union at {{.*}})' has a deleted default constructor}}
+      union { // expected-note-re {{default constructor of '(anonymous union at {{.*}}' is implicitly deleted because field 'test_union::(anonymous union)::(anonymous union)::(anonymous union at {{.*}})' has a deleted default constructor}}
         __weak id g1; // expected-note-re {{default constructor of '(anonymous union at {{.*}}' is implicitly deleted because variant field 'g1' is an ObjC pointer}}
         int g2;
       };

Michael137 · 2025-11-18T13:35:03Z

Thought I'd open this and see what people think of the change in diagnostics. Description explains the motivation but the TL;DR is that we want to be able to print full nested scopes in the future for debug-info purposes. We could add some logic into AppendScope and guard it behind a PrintingPolicy bit, but it would be nice if we could just re-use printNestedNameSpecifier for all that.

CC @zygoloid since you suggested the FIXME originally

clang/test/CXX/drs/cwg6xx.cpp

github-actions · 2025-11-18T14:14:42Z

🐧 Linux x64 Test Results

111356 tests passed
4426 tests skipped

adrian-prantl

From a debug info perspective this change LGTM.

mizvekov

LGTM, nice cleanup.

Endilll

Unit test is not what I expected, but it works.
LGTM

llvm-ci · 2025-11-21T12:09:22Z

LLVM Buildbot has detected a new failure on builder ppc64le-flang-rhel-clang running on ppc64le-flang-rhel-test while building clang at step 3 "clean-build-dir".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/157/builds/42407

Here is the relevant piece of the build log for the reference

Step 3 (clean-build-dir) failure: Delete failed. (failure) (timed out)
Step 6 (test-build-unified-tree-check-flang) failure: 1200 seconds without output running [b'ninja', b'check-flang'], attempting to kill
...
PASS: Flang :: Fir/abstract-results-bindc.fir (3999 of 4009)
PASS: Flang :: Transforms/debug-index-type.fir (4000 of 4009)
PASS: Flang :: Semantics/critical06.f90 (4001 of 4009)
PASS: Flang :: Transforms/debug-derived-type-2.fir (4002 of 4009)
PASS: Flang :: Transforms/debug-dummy-argument-inline.fir (4003 of 4009)
PASS: Flang :: Transforms/DoConcurrent/reduce_device.mlir (4004 of 4009)
PASS: Flang :: Transforms/DoConcurrent/basic_device.mlir (4005 of 4009)
PASS: Flang :: Transforms/DoConcurrent/reduce_add.mlir (4006 of 4009)
PASS: Flang :: Transforms/debug-assumed-rank-array.fir (4007 of 4009)
PASS: Flang :: Intrinsics/math-codegen.fir (4008 of 4009)
command timed out: 1200 seconds without output running [b'ninja', b'check-flang'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=2325.100177

boomanaiden154 · 2025-11-24T14:49:09Z

It seems like this caused a regression in at least one case.

https://godbolt.org/z/bzY1qbboc

For a simple example:

typedef union {
  struct {
    unsigned int a : 1;
    unsigned int b : 1;
    unsigned int c : 1;
    unsigned int d : 2;
    unsigned int e : 1;
    unsigned int f : 1;
    unsigned int g : 1;
  };
  unsigned char val;
} session_u;

session_u bar;

We were getting the following (from -fdump-record-layouts):

         0 | struct session_u::(anonymous at <source>:2:3)
     0:0-0 |   unsigned int a
     0:1-1 |   unsigned int b
     0:2-2 |   unsigned int c
     0:3-4 |   unsigned int d
     0:5-5 |   unsigned int e
     0:6-6 |   unsigned int f
     0:7-7 |   unsigned int g
           | [sizeof=4, dsize=4, align=4,
           |  nvsize=4, nvalign=4]

But now we are getting the following:

*** Dumping AST Record Layout
         0 | struct (anonymous union)::(anonymous at <source>:2:3)
     0:0-0 |   unsigned int a
     0:1-1 |   unsigned int b
     0:2-2 |   unsigned int c
     0:3-4 |   unsigned int d
     0:5-5 |   unsigned int e
     0:6-6 |   unsigned int f
     0:7-7 |   unsigned int g
           | [sizeof=4, dsize=4, align=4,
           |  nvsize=4, nvalign=4]

Where the union is now listed as anonymous despite it being given a name.

boomanaiden154 · 2025-11-24T16:14:08Z

I almost have a fix ready for this.

This is to resolve a regression caused by llvm#168534. Now when we have an anonymous object like a struct or union that has a typedef attached, we print the typedef name instead of listing it as anonymous.

…169364) This is to resolve a regression caused by #168534. Now when we have an anonymous object like a struct or union that has a typedef attached, we print the typedef name instead of listing it as anonymous.

Michael137 · 2025-11-24T18:59:46Z

I almost have a fix ready for this.

Saw you fixed this now. Many thanks!

…sistent In llvm#168534 we made the `TypePrinter` re-use `printNestedNameSpecifier` for printing scopes. However, the way that the names of anonymous/unnamed get printed by the two are slightly inconsistent with each other. `printNestedNameSpecifier` calls all `TagType`s without an identifer `(anonymous)`. On the other hand, `TypePrinter` prints them slightly more accurate (it differentiates anonymous vs. unnamed decls) and allows for some additional customization points. E.g., with `MSVCFormatting`, it will print `\`'` instead of `()`. `printNestedNameSpecifier` already accounts for `MSVCFormatting` for namespaces, but doesn't for `TagType`s. This inconsistency means that if an unnamed tag is printed as part of a scope it's displayed as `(anonymous struct)`, but if it's the entity being whose scope is being printed, then it shows as `(unnamed struct)`. This patch moves the printing of anonymous/unnamed tags into a common helper and re-uses it from `TypePrinter` and `printNestedNameSpecifier`. We also do this from the AST matchers because they were aligned with how `printNestedNameSpecifier` represents the name. I wasn't sure where to put the helper, so I just put it in `TypeBase.h` for now. Though I suspect there's a better home for it, possibly `DeclBase.h`?

llvm#168534) In debug-info we soon have the need to print names using the full scope of the entity (see discussion in llvm#159592). Particularly, when a structure is scoped inside a function, we'd like to emit the name as `func()::foo`. `CGDebugInfo` uses the `TypePrinter` to print type names into debug-info. However, `TypePrinter` stops (and ignores) `DeclContext`s that are functions. I.e., it would just print `foo`. Ideally it would behave the same way `printNestedNameSpecifier` does. The FIXME in https://github.com/llvm/llvm-project/blob/47c1aa4cef638c97b74f3afb7bed60e92bba1f90/clang/lib/AST/TypePrinter.cpp#L1520-L1521 motivated this patch. See llvm#168533 for how this will be used by `CGDebugInfo`. The plan is to introduce a new `PrintingPolicy` that prints anonymous entities using their full scope (including function/anonymous scopes) and the mangling number.

…lvm#169364) This is to resolve a regression caused by llvm#168534. Now when we have an anonymous object like a struct or union that has a typedef attached, we print the typedef name instead of listing it as anonymous.

llvm#168534) In debug-info we soon have the need to print names using the full scope of the entity (see discussion in llvm#159592). Particularly, when a structure is scoped inside a function, we'd like to emit the name as `func()::foo`. `CGDebugInfo` uses the `TypePrinter` to print type names into debug-info. However, `TypePrinter` stops (and ignores) `DeclContext`s that are functions. I.e., it would just print `foo`. Ideally it would behave the same way `printNestedNameSpecifier` does. The FIXME in https://github.com/llvm/llvm-project/blob/47c1aa4cef638c97b74f3afb7bed60e92bba1f90/clang/lib/AST/TypePrinter.cpp#L1520-L1521 motivated this patch. See llvm#168533 for how this will be used by `CGDebugInfo`. The plan is to introduce a new `PrintingPolicy` that prints anonymous entities using their full scope (including function/anonymous scopes) and the mangling number.

Michael137 requested review from AaronBallman and zygoloid November 18, 2025 13:32

Michael137 requested a review from Endilll as a code owner November 18, 2025 13:32

llvmbot added clang Clang issues not falling into any other category clang:frontend Language frontend issues, e.g. anything involving "Sema" clang:modules C++20 modules and Clang Header Modules labels Nov 18, 2025

Michael137 requested review from adrian-prantl and dwblaikie November 18, 2025 13:36

Endilll reviewed Nov 18, 2025

View reviewed changes

clang/test/CXX/drs/cwg6xx.cpp Show resolved Hide resolved

Michael137 requested a review from cor3ntin November 19, 2025 13:07

fixup! add test-case for function scope with parameters

9fba42d

adrian-prantl approved these changes Nov 20, 2025

View reviewed changes

mizvekov approved these changes Nov 20, 2025

View reviewed changes

fixup! make dedicated unit-test

8d3ff0e

Endilll approved these changes Nov 20, 2025

View reviewed changes

Michael137 merged commit bb1b82a into llvm:main Nov 21, 2025
10 checks passed

Michael137 deleted the clang/nested-name-specfier-refactor branch November 21, 2025 10:31

boomanaiden154 mentioned this pull request Nov 24, 2025

[Clang][TypePrinter] Make printNestedNameSpecifier look at typedefs #169364

Merged

Michael137 mentioned this pull request Nov 25, 2025

[clang][TypePrinter] Unify printing of anonymous/unnamed tag types #169445

Open

cofibrant mentioned this pull request Nov 25, 2025

[Clang](TestOnly) Update annotate-parameterized-classes.m check test swiftlang/llvm-project#11895

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

[clang][TypePrinter] Replace AppendScope with printNestedNameSpecifier #168534

[clang][TypePrinter] Replace AppendScope with printNestedNameSpecifier #168534

Michael137 commented Nov 18, 2025

Uh oh!

llvmbot commented Nov 18, 2025 •

edited

Loading

Uh oh!

Michael137 commented Nov 18, 2025

Uh oh!

Uh oh!

github-actions bot commented Nov 18, 2025 •

edited

Loading

Uh oh!

adrian-prantl left a comment

Uh oh!

mizvekov left a comment

Uh oh!

Endilll left a comment

Uh oh!

Uh oh!

llvm-ci commented Nov 21, 2025

Uh oh!

boomanaiden154 commented Nov 24, 2025

Uh oh!

boomanaiden154 commented Nov 24, 2025

Uh oh!

Michael137 commented Nov 24, 2025 •

edited

Loading

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

7 participants

	// FIXME: Consider replacing this with NamedDecl::printNestedNameSpecifier,
	// which can also print names for function and method scopes.

[clang][TypePrinter] Replace AppendScope with printNestedNameSpecifier #168534

[clang][TypePrinter] Replace AppendScope with printNestedNameSpecifier #168534

Conversation

Michael137 commented Nov 18, 2025

Uh oh!

llvmbot commented Nov 18, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Michael137 commented Nov 18, 2025

Uh oh!

Uh oh!

github-actions bot commented Nov 18, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

🐧 Linux x64 Test Results

Uh oh!

adrian-prantl left a comment

Choose a reason for hiding this comment

Uh oh!

mizvekov left a comment

Choose a reason for hiding this comment

Uh oh!

Endilll left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

llvm-ci commented Nov 21, 2025

Uh oh!

boomanaiden154 commented Nov 24, 2025

Uh oh!

boomanaiden154 commented Nov 24, 2025

Uh oh!

Michael137 commented Nov 24, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

7 participants

llvmbot commented Nov 18, 2025 •

edited

Loading

github-actions bot commented Nov 18, 2025 •

edited

Loading

Michael137 commented Nov 24, 2025 •

edited

Loading