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