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 ReferenceCasting::ReferenceCasting( CompilerInstance& compiler )
  36     : FilteringPlugin( compiler )
  37 {
  38 }
  39
  40 void ReferenceCasting::run()
  41 {
  42     TraverseDecl( compiler.getASTContext().getTranslationUnitDecl());
  43 }
  44
  45 // This:
  46 // static void example_method()
  47 // {
  48 //     css::uno::Reference<B> b;
  49 //     css::uno::Reference<A>(b, css::uno::UNO_QUERY);
  50 // }
  51 // Compiles to this AST:
  52 // (CompoundStmt 0x205d430 </noel-extra1/libo-clang/compilerplugins/clang/noel1.cxx:17:1, line:20:1>
  53 //   (DeclStmt 0x20580a8 <line:18:5, col:32>
  54 //     (0x20530e0 "css::uno::Reference<B> refB =
  55 //       (CXXConstructExpr 0x2058078 <col:28> 'css::uno::Reference<B>':'class com::sun::star::uno::Reference<class B>''void(void)')"))
  56 //   (DeclStmt 0x205d418 <line:19:5, col:59>
  57 //     (0x2058310 "css::uno::Reference<A> refA =
  58 //       (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)'
  59 //         (ImplicitCastExpr 0x205d3c0 <col:33> 'const class com::sun::star::uno::BaseReference' lvalue <NoOp>
  60 //           (ImplicitCastExpr 0x205d3a0 <col:33> 'class com::sun::star::uno::BaseReference' lvalue <DerivedToBase (BaseReference)>
  61 //             (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>')))
  62 //         (DeclRefExpr 0x2058398 <col:39, col:49> 'enum com::sun::star::uno::UnoReference_Query' EnumConstant 0x1831de0 'UNO_QUERY' 'enum com::sun::star::uno::UnoReference_Query'))")))
  63 //
  64 //
  65 // This:
  66 // static void example_method1(css::uno::Reference<A>)
  67 // {
  68 // }
  69 // static void example_method2()
  70 // {
  71 //     css::uno::Reference<B> refB;
  72 //     example_method1(css::uno::Reference<A>(refB, css::uno::UNO_QUERY));
  73 // }
  74 //  Compiles to this AST:
  75 // static void example_method1(css::uno::Reference<A>) (CompoundStmt 0x2a74ee8 </noel-extra1/libo-clang/compilerplugins/clang/noel1.cxx:17:1, line:18:1>)
  76 // static void example_method2() (CompoundStmt 0x2a7a650 </noel-extra1/libo-clang/compilerplugins/clang/noel1.cxx:21:1, line:24:1>
  77 //  (DeclStmt 0x2a7a1a8 <line:22:5, col:32>
  78 //    (0x2a751e0 "css::uno::Reference<B> refB =
  79 //      (CXXConstructExpr 0x2a7a178 <col:28> 'css::uno::Reference<B>':'class com::sun::star::uno::Reference<class B>''void(void)')"))
  80 //  (ExprWithCleanups 0x2a7a638 <line:23:5, col:70> 'void'
  81 //    (CallExpr 0x2a7a570 <col:5, col:70> 'void'
  82 //      (ImplicitCastExpr 0x2a7a558 <col:5> 'void (*)(css::uno::Reference<A>)' <FunctionToPointerDecay>
  83 //        (DeclRefExpr 0x2a7a4d8 <col:5> 'void (css::uno::Reference<A>)' lvalue Function 0x2a6ff00 'example_method1' 'void (css::uno::Reference<A>)'))
  84 //      (CXXBindTemporaryExpr 0x2a7a618 <col:21, col:69> 'css::uno::Reference<A>':'class com::sun::star::uno::Reference<class A>' (CXXTemporary 0x2a7a610)
  85 //        (CXXConstructExpr 0x2a7a5d8 <col:21, col:69> 'css::uno::Reference<A>':'class com::sun::star::uno::Reference<class A>''void (const Reference<class A> &)' elidable
  86 //          (MaterializeTemporaryExpr 0x2a7a5c0 <col:21, col:69> 'const Reference<class A>':'const class com::sun::star::uno::Reference<class A>' lvalue
  87 //            (ImplicitCastExpr 0x2a7a5a8 <col:21, col:69> 'const Reference<class A>':'const class com::sun::star::uno::Reference<class A>' <NoOp>
  88 //              (CXXBindTemporaryExpr 0x2a7a4b8 <col:21, col:69> 'css::uno::Reference<A>':'class com::sun::star::uno::Reference<class A>' (CXXTemporary 0x2a7a4b0)
  89 //                (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)'
  90 //                  (ImplicitCastExpr 0x2a7a448 <col:44> 'const class com::sun::star::uno::BaseReference' lvalue <NoOp>
  91 //                    (ImplicitCastExpr 0x2a7a428 <col:44> 'class com::sun::star::uno::BaseReference' lvalue <DerivedToBase (BaseReference)>
  92 //                      (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>')))
  93 //                  (DeclRefExpr 0x2a7a398 <col:50, col:60> 'enum com::sun::star::uno::UnoReference_Query' EnumConstant 0x224ee20 'UNO_QUERY' 'enum com::sun::star::uno::UnoReference_Query'))))))))))
  94
  95 static const Type* extractTemplateType(Expr* cce);
  96
  97 bool ReferenceCasting::VisitCXXConstructExpr( CXXConstructExpr* cce )
  98 {
  99     // don't bother processing anything in the Reference.h file. Makes my life easier when debugging this.
 100     if( StringRef(compiler.getSourceManager().getPresumedLoc( cce->getSourceRange().getBegin() )).find( "Reference.h" ) != StringRef::npos )
 101         return true;
 102
 103     // look for calls to the Reference<T>(x,UNO_something) constructor
 104     if( cce->getConstructor()->getNameInfo().getName().getAsString() != "Reference" )
 105         return true;
 106
 107     if( cce->getNumArgs() != 2 )
 108         return true;
 109
 110     // extract the type parameter passed to the template
 111     const Type * templateParamType = extractTemplateType(cce);
 112     if ( !templateParamType )
 113         return true;
 114
 115     // extract the type of the first parameter passed to the constructor
 116     Expr* constructorArg0 = cce->getArg(0);
 117     if( !constructorArg0 )
 118        return true;
 119
 120     // ignore the Reference(XInterface*,...) constructor
 121     if( constructorArg0->getType()->isPointerType() )
 122        return true;
 123
 124     // drill down the expression tree till we hit the bottom
 125     DeclRefExpr* constructorSubArg2;
 126     Expr* constructorArg0SubExpr = constructorArg0;
 127     for(;;)
 128     {
 129         // if we've hit the member expression we want, break
 130         constructorSubArg2 = dyn_cast<DeclRefExpr>( constructorArg0SubExpr );
 131         if( constructorSubArg2 )
 132             break;
 133         CastExpr* tmp1 = dyn_cast<CastExpr>( constructorArg0SubExpr );
 134         if( tmp1 ) {
 135             constructorArg0SubExpr = tmp1->getSubExpr();
 136             continue;
 137         }
 138         MaterializeTemporaryExpr* tmp2 = dyn_cast<MaterializeTemporaryExpr>( constructorArg0SubExpr );
 139         if( tmp2 ) {
 140             constructorArg0SubExpr = tmp2->GetTemporaryExpr();
 141             continue;
 142         }
 143         CXXBindTemporaryExpr* tmp3 = dyn_cast<CXXBindTemporaryExpr>( constructorArg0SubExpr );
 144         if( tmp3 ) {
 145             constructorArg0SubExpr = tmp3->getSubExpr();
 146             continue;
 147         }
 148         CXXTemporaryObjectExpr* tmp4 = dyn_cast<CXXTemporaryObjectExpr>( constructorArg0SubExpr );
 149         if( tmp4 ) {
 150             constructorArg0SubExpr = tmp4->getArg(0);
 151             continue;
 152         }
 153         return true;
 154     }
 155
 156     const Type * tmp3 = extractTemplateType( constructorSubArg2 );
 157     if ( !tmp3 )
 158         return true;
 159
 160     const RecordType* templateParamRT = dyn_cast<RecordType>( templateParamType );
 161     const RecordType* constructorArgRT = dyn_cast<RecordType>( tmp3 );
 162     if( !templateParamRT || !constructorArgRT )
 163        return true;
 164
 165     CXXRecordDecl* templateParamRD = dyn_cast<CXXRecordDecl>( templateParamRT->getDecl() );
 166     CXXRecordDecl* constructorArgRD = dyn_cast<CXXRecordDecl>( constructorArgRT->getDecl() );
 167
 168     if (constructorArgRD->Equals(templateParamRD) || constructorArgRD->isDerivedFrom(templateParamRD))
 169         report( DiagnosticsEngine::Warning,
 170                 "the source reference is already a subtype of the destination reference",
 171                 cce->getLocStart()) // and the exact position where the message should point
 172                     << cce->getSourceRange(); // and the full return statement to highlight (optional)
 173
 174     return true;
 175 }
 176
 177 static const Type* extractTemplateType(Expr* cce)
 178 {
 179     QualType cceQT = cce->getType();
 180     const Type* cceType = cceQT.getTypePtr();
 181     const TemplateSpecializationType* cceTST = dyn_cast<TemplateSpecializationType>( cceType );
 182     if( !cceTST )
 183         return NULL;
 184     if( cceTST->getNumArgs() != 1 )
 185         return NULL;
 186     const TemplateArgument & cceTA = cceTST->getArg(0);
 187     QualType templateParamQT = cceTA.getAsType();
 188     return templateParamQT.getTypePtr();
 189 }
 190
 191 static Plugin::Registration< ReferenceCasting > X( "referencecasting" );
 192
 193 } // namespace
 194
 195 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */