[LLVMdev] Libclang get class name from DeclRefExpr

[sam at darkfunction.com]

Hi guys,

I am trying to extract the class name of a parameter to a method call 
in objective-C. The code I am parsing is:

- (void)testAddConcreteDataModel:(DFDemoDataModelOne*)helpmeh {
     [self.dataModels addObject:helpmeh];
}
And the result I need is the type of class of helpmeh, which is 
"DFDemoDataModelOne".

So far I have the following code, which outputs: 
"[(DFDataModelContainer).dataModels addObject:helpmeh]"

     if (cursor.kind == CXCursor_ObjCMessageExpr) {
         __block NSString* memberName = nil;
         __block NSString* ownerClassName = nil;
         __block NSString* methodName = [NSString 
stringWithUTF8String:clang_getCString(clang_getCursorDisplayName(cursor))];

         clang_visitChildrenWithBlock(cursor, ^enum 
CXChildVisitResult(CXCursor cursor, CXCursor parent) {
             if (cursor.kind == CXCursor_MemberRefExpr) {
                 memberName = [NSString 
stringWithUTF8String:clang_getCString(clang_getCursorDisplayName(cursor))];
                 ownerClassName = [NSString 
stringWithUTF8String:clang_getCString(clang_getCursorDisplayName(clang_getCursorSemanticParent(clang_getCursorReferenced(cursor))))];
             } else {
                 if (memberName) {
                     NSString* param = [NSString 
stringWithUTF8String:clang_getCString(clang_getCursorDisplayName(cursor))];
                     NSLog(@"[(%@).%@ %@%@]", ownerClassName, 
memberName, methodName, param);
                     clang_visitChildrenWithBlock(cursor, ^enum 
CXChildVisitResult(CXCursor cursor, CXCursor parent) {

                          // test
                          if ([param isEqualToString:@"helpmeh"] && 
cursor.kind == CXCursor_DeclRefExpr) {
                             // found the interesting part.. what now?
                          }
                          return CXChildVisit_Recurse;
                      }
                 }
             }
             return CXChildVisit_Continue;
         }
     }
I'm just a bit lost as to how to extract information from cursors- when 
I AST dump my class I can see the information I need is all there (see 
the last line):

|-ObjCMethodDecl 0x112790f90 <line:32:1, line:34:1> - 
testAddConcreteDataModel: 'void'
   | |-ImplicitParamDecl 0x112791960 <<invalid sloc>> self 
'DFDataModelContainer *const __strong'
   | |-ImplicitParamDecl 0x1127919c0 <<invalid sloc>> _cmd 'SEL':'SEL *'
   | |-ParmVarDecl 0x112791040 <line:32:35, col:55> helpmeh 
'DFDemoDataModelOne *__strong'
   | `-CompoundStmt 0x112791bf0 <col:63, line:34:1>
   |   `-ExprWithCleanups 0x112791bd8 <line:33:5, col:39> 'void'
   |     `-ObjCMessageExpr 0x112791ba0 <col:5, col:39> 'void' 
selector=addObject:
   |       |-PseudoObjectExpr 0x112791b48 <col:6, col:11> 
'NSMutableArray *'
   |       | |-ObjCPropertyRefExpr 0x112791ad0 <col:6, col:11> 
'<pseudo-object type>' lvalue objcproperty Kind=PropertyRef 
Property="dataModels" Messaging=Getter
   |       | | `-OpaqueValueExpr 0x112791ab0 <col:6> 
'DFDataModelContainer *'
   |       | |   `-ImplicitCastExpr 0x112791a40 <col:6> 
'DFDataModelContainer *' <LValueToRValue>
   |       | |     `-DeclRefExpr 0x112791a18 <col:6> 
'DFDataModelContainer *const __strong' lvalue ImplicitParam 0x112791960 
'self' 'DFDataModelContainer *const __strong'
   |       | |-OpaqueValueExpr 0x112791ab0 <col:6> 'DFDataModelContainer 
*'
   |       | | `-ImplicitCastExpr 0x112791a40 <col:6> 
'DFDataModelContainer *' <LValueToRValue>
   |       | |   `-DeclRefExpr 0x112791a18 <col:6> 'DFDataModelContainer 
*const __strong' lvalue ImplicitParam 0x112791960 'self' 
'DFDataModelContainer *const __strong'
   |       | `-ImplicitCastExpr 0x112791b30 <col:11> 'NSMutableArray *' 
<ARCReclaimReturnedObject>
   |       |   `-ObjCMessageExpr 0x112791b00 <col:11> 'NSMutableArray *' 
selector=dataModels
   |       |     `-OpaqueValueExpr 0x112791ab0 <col:6> 
'DFDataModelContainer *'
   |       |       `-ImplicitCastExpr 0x112791a40 <col:6> 
'DFDataModelContainer *' <LValueToRValue>
   |       |         `-DeclRefExpr 0x112791a18 <col:6> 
'DFDataModelContainer *const __strong' lvalue ImplicitParam 0x112791960 
'self' 'DFDataModelContainer *const __strong'
   |       `-ImplicitCastExpr 0x112791b88 <col:32> 'id':'id' <BitCast>
   |         `-ImplicitCastExpr 0x112791b70 <col:32> 'DFDemoDataModelOne 
*' <LValueToRValue>
   |           `-DeclRefExpr 0x112791a88 <col:32> 'DFDemoDataModelOne 
*__strong' lvalue ParmVar 0x112791040 'helpmeh' 'DFDemoDataModelOne 
*__strong'

I have tried grabbing the semantic parent of the DeclRefExpr but the 
cursor kind is CXCursor_FirstInvalid. Now I'm stuck!

Any help appreciated,
Sam