compilerplugins/clang/bodynotinblock.cxx

   1 /*
   2  * This file is part of the LibreOffice project.
   3  *
   4  * Based on LLVM/Clang.
   5  *
   6  * This file is distributed under the University of Illinois Open Source
   7  * License. See LICENSE.TXT for details.
   8  *
   9  */
  10
  11 #include "bodynotinblock.hxx"
  12
  13 namespace loplugin
  14 {
  15
  16 /*
  17 This is a compile check.
  18
  19 Check for two statements that are both indented to look like a body of if/while/for
  20 but are not inside a compound statement and thus the second one is unrelated.
  21
  22 For example:
  23
  24     if( a != 0 )
  25         b = 2;
  26         c = 3;
  27
  28 Here either both statements should be inside {} or the second statement in indented wrong.
  29 */
  30
  31 BodyNotInBlock::BodyNotInBlock( CompilerInstance& compiler )
  32     : Plugin( compiler )
  33     {
  34     }
  35
  36 void BodyNotInBlock::run()
  37     {
  38     TraverseDecl( compiler.getASTContext().getTranslationUnitDecl());
  39     }
  40
  41 bool BodyNotInBlock::VisitFunctionDecl( const FunctionDecl* declaration )
  42     {
  43     if( ignoreLocation( declaration ))
  44         return true;
  45     if( !declaration->doesThisDeclarationHaveABody())
  46         return true;
  47     StmtParents parents;
  48     traverseStatement( declaration->getBody(), parents );
  49     return true;
  50     }
  51
  52 void BodyNotInBlock::traverseStatement( const Stmt* stmt, StmtParents& parents )
  53     {
  54     parents.push_back( stmt );
  55     for( ConstStmtIterator it = stmt->child_begin();
  56          it != stmt->child_end();
  57          ++it )
  58         {
  59         if( *it != NULL ) // some children can be apparently NULL
  60             {
  61             traverseStatement( *it, parents ); // substatements first
  62             parents.push_back( *it );
  63             if( const IfStmt* ifstmt = dyn_cast< IfStmt >( *it ))
  64                 {
  65                 checkBody( ifstmt->getThen(), ifstmt->getIfLoc(), parents, 0, ifstmt->getElse() != NULL );
  66                 checkBody( ifstmt->getElse(), ifstmt->getElseLoc(), parents, 0 );
  67                 }
  68             else if( const WhileStmt* whilestmt = dyn_cast< WhileStmt >( *it ))
  69                 checkBody( whilestmt->getBody(), whilestmt->getWhileLoc(), parents, 1 );
  70             else if( const ForStmt* forstmt = dyn_cast< ForStmt >( *it ))
  71                 checkBody( forstmt->getBody(), forstmt->getForLoc(), parents, 2 );
  72             else if( const CXXForRangeStmt* forstmt = dyn_cast< CXXForRangeStmt >( *it ))
  73                 checkBody( forstmt->getBody(), forstmt->getForLoc(), parents, 2 );
  74             parents.pop_back();
  75             }
  76         }
  77     assert( parents.back() == stmt );
  78     parents.pop_back();
  79     }
  80
  81 void BodyNotInBlock::checkBody( const Stmt* body, SourceLocation stmtLocation, const StmtParents& parents,
  82     int stmtType, bool dontGoUp )
  83     {
  84     if( body == NULL || parents.size() < 2 )
  85         return;
  86     // TODO: If the if/else/while/for comes from a macro expansion, ignore it completely for
  87     // now. The code below could assume everything is in the same place (and thus also column)
  88     // and give a false warning. Moreover some macros are rather lousily written and would
  89     // result in poor formatting. To be evaluated later, maybe this could be handled
  90     // including macro expansion.
  91     if( stmtLocation.isMacroID())
  92         return;
  93     if( dyn_cast< CompoundStmt >( body ))
  94         return; // if body is a compound statement, then it is in {}
  95     // Find the next statement (in source position) after 'body'.
  96     for( int parent_pos = parents.size() - 2; // start from grandparent
  97          parent_pos >= 0;
  98          --parent_pos )
  99         {
 100         for( ConstStmtIterator it = parents[ parent_pos ]->child_begin();
 101              it != parents[ parent_pos ]->child_end();
 102              )
 103             {
 104             if( *it == parents[ parent_pos + 1 ] ) // found grand(grand...)parent
 105                 {
 106                 // get next statement after our (grand...)parent
 107                 ++it;
 108                 while( it != parents[ parent_pos ]->child_end() && *it == NULL )
 109                     ++it; // skip empty ones (missing 'else' bodies for example)
 110                 if( it != parents[ parent_pos ]->child_end())
 111                     {
 112                     bool invalid1, invalid2;
 113                     unsigned bodyColumn = compiler.getSourceManager()
 114                         .getPresumedColumnNumber( body->getLocStart(), &invalid1 );
 115                     unsigned nextStatementColumn = compiler.getSourceManager()
 116                         .getPresumedColumnNumber( (*it)->getLocStart(), &invalid2 );
 117                     if( invalid1 || invalid2 )
 118                         return;
 119                     if( bodyColumn == nextStatementColumn )
 120                         {
 121                         report( DiagnosticsEngine::Warning,
 122                             "statement aligned as second statement in %select{if|while|for}0 body but not in a statement block",
 123                             (*it)->getLocStart()) << stmtType;
 124                         report( DiagnosticsEngine::Note,
 125                             "%select{if|while|for}0 body statement is here",
 126                             body->getLocStart()) << stmtType;
 127                         }
 128                     return;
 129                     }
 130                 // else we need to go higher to find the next statement
 131                 }
 132             else
 133                 ++it;
 134             }
 135         // If going up would mean leaving a {} block, stop, because the } should
 136         // make it visible the two statements are not in the same body.
 137         if( dyn_cast< CompoundStmt >( parents[ parent_pos ] ))
 138             return;
 139         // If the body to be checked is a body of an if statement that has also
 140         // an else part, don't go up, the else is after the body and should make
 141         // it clear the body does not continue there.
 142         if( dontGoUp )
 143             return;
 144         }
 145     }
 146
 147 static Plugin::Registration< BodyNotInBlock > X( "bodynotinblock" );
 148
 149 } // namespace