[libclang] Expose AtomicType

[slowhog]

Summary

Expose atomic type through the C API.

[slowhog]

Hi,

We use libclang in OpenJDK project Panama for a tool, jextract, to read C header files and generate Java bindings. It's critical for us to be able get the "real" underlying type.

Currently type like _Atomic(int) are not exposed, and libclang will give us a type kind of CXType_Unexposed, and we need a way to get the value type of CXType_Int .

Is there an existing way to do that? I have tried to call clang_getCanonicalType on the unexposed type, but that return the same unexposed type.

Please let me know if the proposed patch is on the right track or not, I would appreciate guidance to get this issue solved.

[slowhog]

Updated to latest

[JornVernee]

Would like to try to draw attention to this patch again, since it seems to have gone under the radar. Can someone review this/help get it integrated? We are still having to work around _Atomic types because we can't get to the underlying value type. Thanks

[aaron.ballman]

I'm sorry about the delay in review, this did fall off my radar. Thank you for bringing it to my attention!

Looks mostly good to me, just a few small nits.

clang/include/clang-c/Index.h

3953

Missing a full stop at the end of the comment.

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

1585

Should elide braces here.

clang/tools/libclang/CXType.cpp

1326–1329

I would probably rewrite this function to:

QualType T = GetQualType(CT);
if (T.isNull() || !T->isAtomicType())
  return MakeCXType(QualType(), GetTU(CT));
const auto *AT = T->castAs<AtomicType>();
return MakeCXType(AT->getValueType(), GetTU(CT));

[slowhog]

Thanks for reviewing, I applied the recommended changes.

[aaron.ballman]

LGTM! Do you need me to commit on your behalf?

[slowhog]

Yes, please help to commit the patch. Thank you for looking after this.

[aaron.ballman]

I've commit on your behalf in 38ca7b11db2d22e0fdfbff3f19276f9796f747d3, thank you for the patch!

clang/include/clang-c/Index.h

  * compatible, thus CINDEX_VERSION_MAJOR is expected to remain stable.
  */
 #define CINDEX_VERSION_MAJOR 0
-#define CINDEX_VERSION_MINOR 59
+#define CINDEX_VERSION_MINOR 60
 
 #define CINDEX_VERSION_ENCODE(major, minor) ( \
       ((major) * 10000)                       \

 
   CXType_OCLIntelSubgroupAVCImeDualRefStreamin = 175,
 
-  CXType_ExtVector = 176
+  CXType_ExtVector = 176,
+  CXType_Atomic = 177
 };
 
 /**

  */
 CINDEX_LINKAGE CXType clang_Type_getModifiedType(CXType T);
 
+/**
+ * Gets the type contained by this atomic type
+ *
+ * If a non-atomic type is passed in, an invalid type is returned.
+ */
+CINDEX_LINKAGE CXType clang_Type_getValueType(CXType CT);
+
 /**
  * Return the offset of the field represented by the Cursor.
  *

clang/test/Index/print-type.c

 
 struct {
   struct {
-    int x;
+    _Atomic int x;
     int y;
   };
 } bar;
 
 void fun(struct { int x; int y; } *param);
 
+_Atomic(unsigned long) aul;
+
 // 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: 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: 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=:30:10 (Definition) [type=struct (anonymous at {{.*}}print-type.c:30:10)] [typekind=Record] [isPOD=1] [nbFields=2] [isAnon=1] [isAnonRecDecl=0]
+// CHECK: VarDecl=aul:32:24 [type=_Atomic(unsigned long)] [typekind=Atomic] [valuetype=unsigned long] [valuetypekind=ULong] [isPOD=0] [isAnonRecDecl=0]

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

         PrintTypeTemplateArgs(CT, " [canonicaltemplateargs/%d=");
       }
     }
+    /* Print the value type if it exists. */
+    {
+      CXType VT = clang_Type_getValueType(T);
+      if (VT.kind != CXType_Invalid) {
+        PrintTypeAndTypeKind(VT, " [valuetype=%s] [valuetypekind=%s]");
+      }
+    }
     /* Print the modified type if it exists. */
     {
       CXType MT = clang_Type_getModifiedType(T);

clang/tools/libclang/CXType.cpp

     TKCASE(Elaborated);
     TKCASE(Pipe);
     TKCASE(Attributed);
+    TKCASE(Atomic);
     default:
       return CXType_Unexposed;
   }

     TKIND(OCLEvent);
     TKIND(OCLQueue);
     TKIND(OCLReserveID);
+    TKIND(Atomic);
   }
 #undef TKIND
   return cxstring::createRef(s);

   }
   return CXTypeNullability_Invalid;
 }
+
+CXType clang_Type_getValueType(CXType CT) {
+  QualType T = GetQualType(CT);
+  const Type *TP = T.getTypePtrOrNull();
+
+  if (TP && TP->getTypeClass() == Type::Atomic)
+    return MakeCXType(cast<AtomicType>(TP)->getValueType(), GetTU(CT));
+
+  return MakeCXType(QualType(), GetTU(CT));
+}

clang/tools/libclang/libclang.exports

 clang_Type_getObjCTypeArg
 clang_Type_getModifiedType
 clang_Type_getNullability
+clang_Type_getValueType
 clang_VerbatimBlockLineComment_getText
 clang_VerbatimLineComment_getText
 clang_HTMLTagComment_getAsString