95 lines
3.2 KiB
C++
95 lines
3.2 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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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 "tutorial2.hxx"
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/*
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This is a compile check.
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Warns about if statements with a comparison followed by literal return false:
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if( a == 1 )
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return false;
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*/
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namespace loplugin
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{
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Tutorial2::Tutorial2( const InstantiationData& data )
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: FilteringPlugin( data )
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{
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}
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void Tutorial2::run()
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{
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// The Clang AST helper class will call VisitIfStmt for every if statement.
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TraverseDecl( compiler.getASTContext().getTranslationUnitDecl());
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}
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// This function is called for every if statement.
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bool Tutorial2::VisitIfStmt( const IfStmt* ifstmt )
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{
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if( ignoreLocation( ifstmt ))
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return true;
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// Check if the condition of the if statement is a binary operator.
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if( const BinaryOperator* oper = dyn_cast< BinaryOperator >( ifstmt->getCond()))
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{
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// And if it's operator==.
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if( oper->getOpcode() == BO_EQ )
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{
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// Now check if the sub-statement is 'return false'.
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const Stmt* warn = NULL; // The return statement (for the warning message).
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// Check if the sub-statement is directly 'return false;'.
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if( isReturnFalse( ifstmt->getThen()))
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warn = ifstmt->getThen();
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// Check if the sub-statement is '{ return false; }'
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else if( const CompoundStmt* compound = dyn_cast< CompoundStmt >( ifstmt->getThen()))
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{
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if( compound->size() == 1 ) // one statement
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if( isReturnFalse( *compound->body_begin())) // check the one sub-statement
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warn = *compound->body_begin();
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}
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if( warn != NULL ) // there is a return statement to warn about.
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{
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report( DiagnosticsEngine::Warning,
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"returning false after if with equality comparison",
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cast< ReturnStmt >( warn )->getRetValue()->getLocStart()) // the 'false' in the return
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<< warn->getSourceRange();
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// Also add a note showing the if statement.
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report( DiagnosticsEngine::Note,
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"the if statement is here",
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ifstmt->getLocStart());
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}
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}
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}
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return true;
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}
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bool Tutorial2::isReturnFalse( const Stmt* stmt )
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{
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// Is it return statement?
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if( const ReturnStmt* returnstmt = dyn_cast< ReturnStmt >( stmt ))
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{
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// dyn_cast_or_null<> can also be passed NULL, unlike dyn_cast<>
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if( const CXXBoolLiteralExpr* boolliteral = dyn_cast_or_null< CXXBoolLiteralExpr >( returnstmt->getRetValue()))
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{
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if( boolliteral->getValue() == false )
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return true;
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}
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}
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return false;
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}
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// Register the plugin action with the LO plugin handling.
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static Plugin::Registration< Tutorial2 > tutorial2( "tutorial2" );
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} // namespace
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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