Changes in src/ControlStruct/MLEMutator.cc [af68f0a:8688ce1]

File:

• src/ControlStruct/MLEMutator.cc (modified) (6 diffs)

src/ControlStruct/MLEMutator.cc

@@ -56 +56 @@
                 bool labeledBlock = !(cmpndStmt->get_labels().empty());
                 if ( labeledBlock ) {
-                        Label brkLabel = generator->newLabel("blockBreak", cmpndStmt);
+                        Label brkLabel = generator->newLabel("blockBreak");
                         enclosingControlStructures.push_back( Entry( cmpndStmt, brkLabel ) );
                 } // if
@@ -80 +80 @@
                 // whether brkLabel and contLabel are used with branch statements and will recursively do the same to nested
                 // loops
-                Label brkLabel = generator->newLabel("loopBreak", loopStmt);
-                Label contLabel = generator->newLabel("loopContinue", loopStmt);
+                Label brkLabel = generator->newLabel("loopBreak");
+                Label contLabel = generator->newLabel("loopContinue");
                 enclosingControlStructures.push_back( Entry( loopStmt, brkLabel, contLabel ) );
                 loopStmt->set_body ( loopStmt->get_body()->acceptMutator( *this ) );
 
-                assert( ! enclosingControlStructures.empty() );
                 Entry &e = enclosingControlStructures.back();
                 // sanity check that the enclosing loops have been popped correctly
@@ -109 +108 @@
                 bool labeledBlock = !(ifStmt->get_labels().empty());
                 if ( labeledBlock ) {
-                        Label brkLabel = generator->newLabel("blockBreak", ifStmt);
+                        Label brkLabel = generator->newLabel("blockBreak");
                         enclosingControlStructures.push_back( Entry( ifStmt, brkLabel ) );
                 } // if
 
                 Parent::mutate( ifStmt );
-
+                
                 if ( labeledBlock ) {
                         if ( ! enclosingControlStructures.back().useBreakExit().empty() ) {
@@ -127 +126 @@
         Statement *MLEMutator::handleSwitchStmt( SwitchClass *switchStmt ) {
                 // generate a label for breaking out of a labeled switch
-                Label brkLabel = generator->newLabel("switchBreak", switchStmt);
+                Label brkLabel = generator->newLabel("switchBreak");
                 enclosingControlStructures.push_back( Entry(switchStmt, brkLabel) );
                 mutateAll( switchStmt->get_statements(), *this );
@@ -159 +158 @@
 
                 std::list< Entry >::reverse_iterator targetEntry;
-                switch ( branchStmt->get_type() ) {
-                        case BranchStmt::Goto:
-                                return branchStmt;
-                        case BranchStmt::Continue:
-                        case BranchStmt::Break: {
-                                bool isContinue = branchStmt->get_type() == BranchStmt::Continue;
-                                // unlabeled break/continue
-                                if ( branchStmt->get_target() == "" ) {
-                                        if ( isContinue ) {
-                                                // continue target is outermost loop
-                                                targetEntry = std::find_if( enclosingControlStructures.rbegin(), enclosingControlStructures.rend(), [](Entry &e) { return isLoop( e.get_controlStructure() ); } );
-                                        } else {
-                                                // break target is outmost control structure
-                                                if ( enclosingControlStructures.empty() ) throw SemanticError( "'break' outside a loop, switch, or labelled block" );
-                                                targetEntry = enclosingControlStructures.rbegin();
-                                        } // if
-                                } else {
-                                        // labeled break/continue - lookup label in table to find attached control structure
-                                        targetEntry = std::find( enclosingControlStructures.rbegin(), enclosingControlStructures.rend(), (*targetTable)[branchStmt->get_target()] );
-                                } // if
-                                // ensure that selected target is valid
-                                if ( targetEntry == enclosingControlStructures.rend() || (isContinue && ! isLoop( targetEntry->get_controlStructure() ) ) ) {
-                                        throw SemanticError( toString( (isContinue ? "'continue'" : "'break'"), " target must be an enclosing ", (isContinue ? "loop: " : "control structure: "), originalTarget ) );
-                                } // if
-                                break;
-                        }
-                        default:
-                                assert( false );
-                } // switch
+                if ( branchStmt->get_type() == BranchStmt::Goto ) {
+                        return branchStmt;
+                } else if ( branchStmt->get_type() == BranchStmt::Continue) {
+                        // continue target must be a loop
+                        if ( branchStmt->get_target() == "" ) {
+                                targetEntry = std::find_if( enclosingControlStructures.rbegin(), enclosingControlStructures.rend(), [](Entry &e) { return isLoop( e.get_controlStructure() ); } );
+                        } else {
+                                // labelled continue - lookup label in table ot find attached control structure
+                                targetEntry = std::find( enclosingControlStructures.rbegin(), enclosingControlStructures.rend(), (*targetTable)[branchStmt->get_target()] );
+                        } // if
+                        if ( targetEntry == enclosingControlStructures.rend() || ! isLoop( targetEntry->get_controlStructure() ) ) {
+                                throw SemanticError( "'continue' target must be an enclosing loop: " + originalTarget );
+                        } // if
+                } else if ( branchStmt->get_type() == BranchStmt::Break ) {
+                        if ( enclosingControlStructures.empty() ) throw SemanticError( "'break' outside a loop, switch, or labelled block" );
+                        targetEntry = enclosingControlStructures.rbegin();
+                } else {
+                        assert( false );
+                } // if
+
+                if ( branchStmt->get_target() != "" && targetTable->find( branchStmt->get_target() ) == targetTable->end() ) {
+                        throw SemanticError("The label defined in the exit loop statement does not exist: " + originalTarget );  // shouldn't happen (since that's already checked)
+                } // if
 
                 // branch error checks, get the appropriate label name and create a goto
@@ -204 +197 @@
                 } // switch
 
-                // transform break/continue statements into goto to simplify later handling of branches
-                delete branchStmt;
-                return new BranchStmt( std::list<Label>(), exitLabel, BranchStmt::Goto );
+                if ( branchStmt->get_target() == "" && branchStmt->get_type() != BranchStmt::Continue ) {
+                        // unlabelled break/continue - can keep branch as break/continue for extra semantic information, but add
+                        // exitLabel as its destination so that label passes can easily determine where the break/continue goes to
+                        branchStmt->set_target( exitLabel );
+                        return branchStmt;
+                } else {
+                        // labelled break/continue - can't easily emulate this with break and continue, so transform into a goto
+                        delete branchStmt;
+                        return new BranchStmt( std::list<Label>(), exitLabel, BranchStmt::Goto );
+                } // if
         }