113 lines
4.1 KiB
C++
113 lines
4.1 KiB
C++
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/*
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* This file is part of the LibreOffice project.
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*
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* Based on LLVM/Clang.
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*
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* This file is distributed under the University of Illinois Open Source
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* License. See LICENSE.TXT for details.
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*
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*/
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#include "unusedvariablecheck.hxx"
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#include <clang/Basic/SourceManager.h>
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using namespace clang;
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namespace loplugin
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{
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/*
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Check for unused classes where the compiler cannot decide (e.g. because of
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non-trivial or extern ctors) if a variable is unused if only its ctor/dtor
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are called and nothing else. For example std::vector is a class where
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the ctor may call further functions, but an unused std::string variable
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does nothing. On the other hand, std::auto_ptr instances are used
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for their dtors and so are not unused even if not otherwise accessed.
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Classes which are safe to be warned about need to be marked using
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SAL_WARN_UNUSED (see e.g. OUString). For external classes such as std::vector
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that cannot be edited there is a manual list below.
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*/
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UnusedVariableCheck::UnusedVariableCheck( ASTContext& context )
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: context( context )
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{
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}
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void UnusedVariableCheck::run()
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{
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TraverseDecl( context.getTranslationUnitDecl());
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}
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DiagnosticBuilder UnusedVariableCheck::report( DiagnosticsEngine::Level level, StringRef message, SourceLocation loc )
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{
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// Do some mappings (e.g. for -Werror) that clang does not do for custom messages for some reason.
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DiagnosticsEngine& diag = context.getDiagnostics();
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if( level == DiagnosticsEngine::Warning && diag.getWarningsAsErrors())
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level = DiagnosticsEngine::Error;
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if( level == DiagnosticsEngine::Error && diag.getErrorsAsFatal())
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level = DiagnosticsEngine::Fatal;
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return diag.Report( loc, diag.getCustomDiagID( level, message ));
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}
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bool UnusedVariableCheck::VisitNamedDecl( NamedDecl* declaration )
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{
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// TODO also LO header files? or a subdir?
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if( !context.getSourceManager().isFromMainFile( declaration->getLocStart()))
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return true;
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if( !isa< VarDecl >( declaration ))
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return true;
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const VarDecl* var = cast< VarDecl >( declaration );
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if( var->isReferenced() || var->isUsed())
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return true;
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if( CXXRecordDecl* type = var->getType()->getAsCXXRecordDecl())
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{
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bool warn_unused = false;
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if( type->hasAttrs())
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{
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// Clang currently has no support for custom attributes, but
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// the annotate attribute comes close, so check for __attribute__((annotate("lo_warn_unused")))
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for( specific_attr_iterator<AnnotateAttr> i = type->specific_attr_begin<AnnotateAttr>(),
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e = type->specific_attr_end<AnnotateAttr>();
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i != e;
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++i )
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{
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if( (*i)->getAnnotation() == "lo_warn_unused" )
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{
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warn_unused = true;
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break;
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}
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}
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}
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if( !warn_unused )
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{
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std::string n = type->getQualifiedNameAsString();
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// Check some common non-LO types.
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if( n == "std::string" || n == "std::basic_string"
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|| n == "std::list" || n == "std::__debug::list"
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|| n == "std::vector" || n == "std::__debug::vector" )
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warn_unused = true;
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}
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if( warn_unused )
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{
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if( const ParmVarDecl* param = dyn_cast< ParmVarDecl >( var ))
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{
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// If this declaration does not have a body, then the parameter is indeed not used,
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// so ignore.
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if( const FunctionDecl* func = dyn_cast< FunctionDecl >( param->getParentFunctionOrMethod()))
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if( !func->doesThisDeclarationHaveABody())
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return true;
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report( DiagnosticsEngine::Warning, "unused parameter %0 [loplugin]",
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var->getLocStart()) << var->getDeclName();
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}
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else
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report( DiagnosticsEngine::Warning, "unused variable %0 [loplugin]",
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var->getLocStart()) << var->getDeclName();
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}
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}
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return true;
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}
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} // namespace
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