compilerplugins/clang/store/referencecasting.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * Based on LLVM/Clang.
   6  *
   7  * This file is distributed under the University of Illinois Open Source
   8  * License. See LICENSE.TXT for details.
   9  *
  10  */
  11
  12 #include "referencecasting.hxx"
  13
  14 #include <clang/AST/Attr.h>
  15 #include <iostream>
  16
  17 namespace loplugin
  18 {
  19
  20 /*
  21 This is a compile-time checker.
  22
  23 Check for cases where we have
  24  - two IDL interfaces A and B,
  25  - B extends A
  26  - we are converting a Reference<B> to a Reference<A>
  27
  28 Note that it generates the occasional false positive.
  29
  30 Also, it makes clang3.2 crash on about 4 files in the LO codebase.
  31 I have logged a bug here:
  32   http://llvm.org/bugs/show_bug.cgi?id=15902
  33
  34 */
  35
  36 ReferenceCasting::ReferenceCasting( CompilerInstance& compiler )
  37     : Plugin( compiler )
  38 {
  39 }
  40
  41 void ReferenceCasting::run()
  42 {
  43     TraverseDecl( compiler.getASTContext().getTranslationUnitDecl());
  44 }
  45
  46 // This:
  47 // static void example_method()
  48 // {
  49 //     css::uno::Reference<B> b;
  50 //     css::uno::Reference<A>(b, css::uno::UNO_QUERY);
  51 // }
  52 // Compiles to this AST:
  53 // (CompoundStmt 0x205d430 </noel-extra1/libo-clang/compilerplugins/clang/noel1.cxx:17:1, line:20:1>
  54 //   (DeclStmt 0x20580a8 <line:18:5, col:32>
  55 //     (0x20530e0 "css::uno::Reference<B> refB =
  56 //       (CXXConstructExpr 0x2058078 <col:28> 'css::uno::Reference<B>':'class com::sun::star::uno::Reference<class B>''void (void)')"))
  57 //   (DeclStmt 0x205d418 <line:19:5, col:59>
  58 //     (0x2058310 "css::uno::Reference<A> refA =
  59 //       (CXXConstructExpr 0x205d3d8 <col:28, col:58> 'css::uno::Reference<A>':'class com::sun::star::uno::Reference<class A>''void (const class com::sun::star::uno::BaseReference &, enum com::sun::star::uno::UnoReference_Query)'
  60 //         (ImplicitCastExpr 0x205d3c0 <col:33> 'const class com::sun::star::uno::BaseReference' lvalue <NoOp>
  61 //           (ImplicitCastExpr 0x205d3a0 <col:33> 'class com::sun::star::uno::BaseReference' lvalue <DerivedToBase (BaseReference)>
  62 //             (DeclRefExpr 0x20582a0 <col:33> 'css::uno::Reference<B>':'class com::sun::star::uno::Reference<class B>' lvalue Var 0x20530e0 'refB' 'css::uno::Reference<B>':'class com::sun::star::uno::Reference<class B>')))
  63 //         (DeclRefExpr 0x2058398 <col:39, col:49> 'enum com::sun::star::uno::UnoReference_Query' EnumConstant 0x1831de0 'UNO_QUERY' 'enum com::sun::star::uno::UnoReference_Query'))")))
  64 //
  65 //
  66 // This:
  67 // static void example_method1(css::uno::Reference<A>)
  68 // {
  69 // }
  70 // static void example_method2()
  71 // {
  72 //     css::uno::Reference<B> refB;
  73 //     example_method1(css::uno::Reference<A>(refB, css::uno::UNO_QUERY));
  74 // }
  75 //  Compiles to this AST:
  76 // static void example_method1(css::uno::Reference<A>) (CompoundStmt 0x2a74ee8 </noel-extra1/libo-clang/compilerplugins/clang/noel1.cxx:17:1, line:18:1>)
  77 // static void example_method2() (CompoundStmt 0x2a7a650 </noel-extra1/libo-clang/compilerplugins/clang/noel1.cxx:21:1, line:24:1>
  78 //  (DeclStmt 0x2a7a1a8 <line:22:5, col:32>
  79 //    (0x2a751e0 "css::uno::Reference<B> refB =
  80 //      (CXXConstructExpr 0x2a7a178 <col:28> 'css::uno::Reference<B>':'class com::sun::star::uno::Reference<class B>''void (void)')"))
  81 //  (ExprWithCleanups 0x2a7a638 <line:23:5, col:70> 'void'
  82 //    (CallExpr 0x2a7a570 <col:5, col:70> 'void'
  83 //      (ImplicitCastExpr 0x2a7a558 <col:5> 'void (*)(css::uno::Reference<A>)' <FunctionToPointerDecay>
  84 //        (DeclRefExpr 0x2a7a4d8 <col:5> 'void (css::uno::Reference<A>)' lvalue Function 0x2a6ff00 'example_method1' 'void (css::uno::Reference<A>)'))
  85 //      (CXXBindTemporaryExpr 0x2a7a618 <col:21, col:69> 'css::uno::Reference<A>':'class com::sun::star::uno::Reference<class A>' (CXXTemporary 0x2a7a610)
  86 //        (CXXConstructExpr 0x2a7a5d8 <col:21, col:69> 'css::uno::Reference<A>':'class com::sun::star::uno::Reference<class A>''void (const Reference<class A> &)' elidable
  87 //          (MaterializeTemporaryExpr 0x2a7a5c0 <col:21, col:69> 'const Reference<class A>':'const class com::sun::star::uno::Reference<class A>' lvalue
  88 //            (ImplicitCastExpr 0x2a7a5a8 <col:21, col:69> 'const Reference<class A>':'const class com::sun::star::uno::Reference<class A>' <NoOp>
  89 //              (CXXBindTemporaryExpr 0x2a7a4b8 <col:21, col:69> 'css::uno::Reference<A>':'class com::sun::star::uno::Reference<class A>' (CXXTemporary 0x2a7a4b0)
  90 //                (CXXTemporaryObjectExpr 0x2a7a460 <col:21, col:69> 'css::uno::Reference<A>':'class com::sun::star::uno::Reference<class A>''void (const class com::sun::star::uno::BaseReference &, enum com::sun::star::uno::UnoReference_Query)'
  91 //                  (ImplicitCastExpr 0x2a7a448 <col:44> 'const class com::sun::star::uno::BaseReference' lvalue <NoOp>
  92 //                    (ImplicitCastExpr 0x2a7a428 <col:44> 'class com::sun::star::uno::BaseReference' lvalue <DerivedToBase (BaseReference)>
  93 //                      (DeclRefExpr 0x2a7a340 <col:44> 'css::uno::Reference<B>':'class com::sun::star::uno::Reference<class B>' lvalue Var 0x2a751e0 'refB' 'css::uno::Reference<B>':'class com::sun::star::uno::Reference<class B>')))
  94 //                  (DeclRefExpr 0x2a7a398 <col:50, col:60> 'enum com::sun::star::uno::UnoReference_Query' EnumConstant 0x224ee20 'UNO_QUERY' 'enum com::sun::star::uno::UnoReference_Query'))))))))))
  95
  96 static const Type* extractTemplateType(Expr* cce);
  97
  98 bool ReferenceCasting::VisitCXXConstructExpr( CXXConstructExpr* cce )
  99 {
 100     // don't bother processing anything in the Reference.h file. Makes my life easier when debugging this.
 101     if( compiler.getSourceManager().getFilename( cce->getSourceRange().getBegin() ).find( "Reference.h" ) != StringRef::npos )
 102         return true;
 103
 104     // look for calls to the Reference<T>(x,UNO_something) constructor
 105     if( cce->getConstructor()->getNameInfo().getName().getAsString() != "Reference" )
 106         return true;
 107
 108     if( cce->getNumArgs() != 2 )
 109         return true;
 110
 111     // extract the type parameter passed to the template
 112     const Type * templateParamType = extractTemplateType(cce);
 113     if ( !templateParamType )
 114         return true;
 115
 116     // extract the type of the first parameter passed to the constructor
 117     Expr* constructorArg0 = cce->getArg(0);
 118     if( !constructorArg0 )
 119        return true;
 120
 121     // ignore the Reference(XInterface*,...) constructor
 122     if( constructorArg0->getType()->isPointerType() )
 123        return true;
 124
 125     // drill down the expression tree till we hit the bottom
 126     DeclRefExpr* constructorSubArg2;
 127     Expr* constructorArg0SubExpr = constructorArg0;
 128     for(;;)
 129     {
 130         // if we've hit the member expression we want, break
 131         constructorSubArg2 = dyn_cast<DeclRefExpr>( constructorArg0SubExpr );
 132         if( constructorSubArg2 )
 133             break;
 134         CastExpr* tmp1 = dyn_cast<CastExpr>( constructorArg0SubExpr );
 135         if( tmp1 ) {
 136             constructorArg0SubExpr = tmp1->getSubExpr();
 137             continue;
 138         }
 139         MaterializeTemporaryExpr* tmp2 = dyn_cast<MaterializeTemporaryExpr>( constructorArg0SubExpr );
 140         if( tmp2 ) {
 141             constructorArg0SubExpr = tmp2->GetTemporaryExpr();
 142             continue;
 143         }
 144         CXXBindTemporaryExpr* tmp3 = dyn_cast<CXXBindTemporaryExpr>( constructorArg0SubExpr );
 145         if( tmp3 ) {
 146             constructorArg0SubExpr = tmp3->getSubExpr();
 147             continue;
 148         }
 149         CXXTemporaryObjectExpr* tmp4 = dyn_cast<CXXTemporaryObjectExpr>( constructorArg0SubExpr );
 150         if( tmp4 ) {
 151             constructorArg0SubExpr = tmp4->getArg(0);
 152             continue;
 153         }
 154         return true;
 155     }
 156
 157     const Type * tmp3 = extractTemplateType( constructorSubArg2 );
 158     if ( !tmp3 )
 159         return true;
 160
 161     const RecordType* templateParamRT = dyn_cast<RecordType>( templateParamType );
 162     const RecordType* constructorArgRT = dyn_cast<RecordType>( tmp3 );
 163     if( !templateParamRT || !constructorArgRT )
 164        return true;
 165
 166     CXXRecordDecl* templateParamRD = dyn_cast<CXXRecordDecl>( templateParamRT->getDecl() );
 167     CXXRecordDecl* constructorArgRD = dyn_cast<CXXRecordDecl>( constructorArgRT->getDecl() );
 168
 169     if (constructorArgRD->Equals(templateParamRD) || constructorArgRD->isDerivedFrom(templateParamRD))
 170         report( DiagnosticsEngine::Warning,
 171                 "the source reference is already a subtype of the destination reference",
 172                 cce->getLocStart()) // and the exact position where the message should point
 173                     << cce->getSourceRange(); // and the full return statement to highlight (optional)
 174
 175     return true;
 176 }
 177
 178 static const Type* extractTemplateType(Expr* cce)
 179 {
 180     QualType cceQT = cce->getType();
 181     const Type* cceType = cceQT.getTypePtr();
 182     const TemplateSpecializationType* cceTST = dyn_cast<TemplateSpecializationType>( cceType );
 183     if( !cceTST )
 184         return NULL;
 185     if( cceTST->getNumArgs() != 1 )
 186         return NULL;
 187     const TemplateArgument & cceTA = cceTST->getArg(0);
 188     QualType templateParamQT = cceTA.getAsType();
 189     return templateParamQT.getTypePtr();
 190 }
 191
 192
 193 static Plugin::Registration< ReferenceCasting > X( "referencecasting" );
 194
 195 } // namespace
 196
 197 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */