[libclang] Restore old clang_Cursor_isAnonymous behaviour

[JornVernee]

Summary

https://reviews.llvm.org/D54996 Changed the behaviour of clang_Cursor_isAnonymous, but there is no alternative available to get the old behaviour in some cases, which is essential for determining if a record is syntactically accessible, e.g.

struct {
  int x;
  int y;
} foo;

struct {
  struct {
    int x;
    int y;
  };
} bar;

void fun(struct { int x; int y; } *param);

The only 'anonymous' struct here is the one nested in bar, since there is no way to reference the struct itself, only the fields within. Though the anonymity applies to the instance itself, not the type.

To avoid confusion, I have added a new function called clang_Cursor_isAnonymousRecordDecl which has the old behaviour of clang_Cursor_isAnonymous (and updated the doc for the latter as well, which was seemingly forgotten).

[JornVernee]

Also, I don't have commit access, so I would need some help with that if this gets accepted :)

[yvvan]

Now we know that somebody else also uses libclang :)
I the mentioned change I only wanted to follow the same logic as in TypePrinter::printTag to cover more anonymity cases.

Adding the old one as an extra function seems totally fine to me. Can you please add some tests for it to clarify the purpose for future users?

[JornVernee]

@yvvan Hows that as a test?

I'm pretty new at this, and it took a while to figure out how to run the tests. I used something like: build\Release\bin\c-index-test.exe -test-print-type .\test\Index\print-type.c | ..\llvm\build\Release\bin\FileCheck .\test\Index\print-type.c, but there's probably an easier way?

[yvvan]

Could you please also upload diff with the full context? It's -U9999 for git and quite similar for svn.
Otherwise looks ok.

test/Index/print-type.c

70

The path will be different depending on the machine and OS. You can {{.*}}print-type.cpp instead (like in https://reviews.llvm.org/D54996).

[yvvan]

Thank you! Sorry that I forgot about the required minor version increment.
I will run tests tomorrow and then I can commit it for you.

include/clang-c/Index.h

35

We also need to increment the minor version because of the new function added.

[JornVernee]

Incremented minor version

[JornVernee]

No worries! I'm already glad there's someone who picked up the review for this so quickly ;)

include/clang-c/Index.h

  * The version constants for the libclang API.
  * CINDEX_VERSION_MINOR should increase when there are API additions.
  * CINDEX_VERSION_MAJOR is intended for "major" source/ABI breaking changes.
  *
  * The policy about the libclang API was always to keep it source and ABI
  * compatible, thus CINDEX_VERSION_MAJOR is expected to remain stable.
  */
 #define CINDEX_VERSION_MAJOR 0
-#define CINDEX_VERSION_MINOR 55
+#define CINDEX_VERSION_MINOR 56
 
 #define CINDEX_VERSION_ENCODE(major, minor) ( \
       ((major) * 10000)                       \
     + ((minor) *     1))
 
 #define CINDEX_VERSION CINDEX_VERSION_ENCODE( \
     CINDEX_VERSION_MAJOR,                     \
     CINDEX_VERSION_MINOR )

  * If the field's type declaration is a dependent type,
  *   CXTypeLayoutError_Dependent is returned.
  * If the field's name S is not found,
  *   CXTypeLayoutError_InvalidFieldName is returned.
  */
 CINDEX_LINKAGE long long clang_Cursor_getOffsetOfField(CXCursor C);
 
 /**
+ * Determine whether the given cursor represents an anonymous
+ * tag or namespace
+ */
+CINDEX_LINKAGE unsigned clang_Cursor_isAnonymous(CXCursor C);
+
+/**
  * Determine whether the given cursor represents an anonymous record
  * declaration.
  */
-CINDEX_LINKAGE unsigned clang_Cursor_isAnonymous(CXCursor C);
+CINDEX_LINKAGE unsigned clang_Cursor_isAnonymousRecordDecl(CXCursor C);
 
 enum CXRefQualifierKind {
   /** No ref-qualifier was provided. */
   CXRefQualifier_None = 0,
   /** An lvalue ref-qualifier was provided (\c &). */
   CXRefQualifier_LValue,
   /** An rvalue ref-qualifier was provided (\c &&). */
   CXRefQualifier_RValue

test/Index/print-type.c

 int __attribute__((vector_size(16))) x;
 typedef int __attribute__((vector_size(16))) int4_t;
 
 int f2(int incompletearray[]);
 
 enum Enum{i}; enum Enum elaboratedEnumType();
 struct Struct{}; struct Struct elaboratedStructType();
 
+struct {
+  int x;
+  int y;
+} foo;
+
+struct {
+  struct {
+    int x;
+    int y;
+  };
+} bar;
+
+void fun(struct { int x; int y; } *param);
+
 // RUN: c-index-test -test-print-type %s | FileCheck %s
 // CHECK: FunctionDecl=f:3:6 (Definition) [type=int *(int *, char *, FooType, int *, void (*)(int))] [typekind=FunctionProto] [canonicaltype=int *(int *, char *, int, int *, void (*)(int))] [canonicaltypekind=FunctionProto] [resulttype=int *] [resulttypekind=Pointer] [args= [int *] [Pointer] [char *] [Pointer] [FooType] [Typedef] [int [5]] [ConstantArray] [void (*)(int)] [Pointer]] [isPOD=0]
 // CHECK: ParmDecl=p:3:13 (Definition) [type=int *] [typekind=Pointer] [isPOD=1] [pointeetype=int] [pointeekind=Int]
 // CHECK: ParmDecl=x:3:22 (Definition) [type=char *] [typekind=Pointer] [isPOD=1] [pointeetype=char] [pointeekind=Char_{{[US]}}]
 // CHECK: ParmDecl=z:3:33 (Definition) [type=FooType] [typekind=Typedef] [canonicaltype=int] [canonicaltypekind=Int] [isPOD=1]
 // CHECK: TypeRef=FooType:1:13 [type=FooType] [typekind=Typedef] [canonicaltype=int] [canonicaltypekind=Int] [isPOD=1]
 // CHECK: ParmDecl=arr:3:40 (Definition) [type=int [5]] [typekind=ConstantArray] [isPOD=1]
 // CHECK: IntegerLiteral= [type=int] [typekind=Int] [isPOD=1]

 // CHECK: VarDecl=x:10:38 [type=__attribute__((__vector_size__(4 * sizeof(int)))) int] [typekind=Vector] [isPOD=1]
 // CHECK: TypedefDecl=int4_t:11:46 (Definition) [type=int4_t] [typekind=Typedef] [canonicaltype=__attribute__((__vector_size__(4 * sizeof(int)))) int] [canonicaltypekind=Vector] [isPOD=1]
 // CHECK: ParmDecl=incompletearray:13:12 (Definition) [type=int []] [typekind=IncompleteArray] [isPOD=1]
 // CHECK: FunctionDecl=elaboratedEnumType:15:25 [type=enum Enum ()] [typekind=FunctionNoProto] [canonicaltype=enum Enum ()] [canonicaltypekind=FunctionNoProto] [resulttype=enum Enum] [resulttypekind=Elaborated] [isPOD=0]
 // CHECK: TypeRef=enum Enum:15:6 [type=enum Enum] [typekind=Enum] [isPOD=1]
 // CHECK: StructDecl=Struct:16:8 (Definition) [type=struct Struct] [typekind=Record] [isPOD=1]
 // CHECK: FunctionDecl=elaboratedStructType:16:32 [type=struct Struct ()] [typekind=FunctionNoProto] [canonicaltype=struct Struct ()] [canonicaltypekind=FunctionNoProto] [resulttype=struct Struct] [resulttypekind=Elaborated] [isPOD=0]
 // CHECK: TypeRef=struct Struct:16:8 [type=struct Struct] [typekind=Record] [isPOD=1]
+// CHECK: StructDecl=:18:1 (Definition) [type=struct (anonymous at {{.*}}print-type.c:18:1)] [typekind=Record] [isPOD=1] [nbFields=2] [isAnon=1] [isAnonRecDecl=0]
+// CHECK: StructDecl=:23:1 (Definition) [type=struct (anonymous at {{.*}}print-type.c:23:1)] [typekind=Record] [isPOD=1] [nbFields=1] [isAnon=1] [isAnonRecDecl=0]
+// CHECK: StructDecl=:24:3 (Definition) [type=struct (anonymous at {{.*}}print-type.c:24:3)] [typekind=Record] [isPOD=1] [nbFields=2] [isAnon=1] [isAnonRecDecl=1]
+// CHECK: StructDecl=:30:10 (Definition) [type=struct (anonymous at {{.*}}print-type.c:30:10)] [typekind=Record] [isPOD=1] [nbFields=2] [isAnon=1] [isAnonRecDecl=0]

tools/c-index-test/c-index-test.c

if (!clang_isInvalid(clang_getCursorKind(cursor))) {
     /* Print if it is an anonymous record or namespace. */
     {
       unsigned isAnon = clang_Cursor_isAnonymous(cursor);
       if (isAnon != 0) {
         printf(" [isAnon=%d]", isAnon);
       }
     }
 
+    /* Print if it is an anonymous record decl */
+    {
+      unsigned isAnonRecDecl = clang_Cursor_isAnonymousRecordDecl(cursor);
+      printf(" [isAnonRecDecl=%d]", isAnonRecDecl);
+    }
+
     printf("\n");
   }
   return CXChildVisit_Recurse;
 }
 
 static void PrintSingleTypeSize(CXType T, const char *TypeKindFormat,
                                 const char *SizeFormat,
                                 const char *AlignFormat) {

tools/libclang/CXType.cpp

if (const NamespaceDecl *ND = dyn_cast_or_null<NamespaceDecl>(D)) {
     return ND->isAnonymousNamespace();
   } else if (const TagDecl *TD = dyn_cast_or_null<TagDecl>(D)) {
     return TD->getTypedefNameForAnonDecl() == nullptr &&
            TD->getIdentifier() == nullptr;
   }
 
   return 0;
 }
+
+unsigned clang_Cursor_isAnonymousRecordDecl(CXCursor C){
+  if (!clang_isDeclaration(C.kind))
+    return 0;
+  const Decl *D = cxcursor::getCursorDecl(C);
+  if (const RecordDecl *FD = dyn_cast_or_null<RecordDecl>(D))
+    return FD->isAnonymousStructOrUnion();
+  return 0;
+}
+
 CXType clang_Type_getNamedType(CXType CT){
   QualType T = GetQualType(CT);
   const Type *TP = T.getTypePtrOrNull();
 
   if (TP && TP->getTypeClass() == Type::Elaborated)
     return MakeCXType(cast<ElaboratedType>(TP)->getNamedType(), GetTU(CT));
 
   return MakeCXType(QualType(), GetTU(CT));