Changeset 27de955 for src/ControlStruct/MLEMutator.cc

Timestamp:

Jun 3, 2015, 3:19:29 PM (9 years ago)

Author:

Rob Schluntz <rschlunt@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, ctor, deferred_resn, demangler, enum, forall-pointer-decay, gc_noraii, jacob/cs343-translation, jenkins-sandbox, master, memory, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, pthread-emulation, qualifiedEnum, resolv-new, string, with_gc

Children:

4162aea9

Parents:

954463b8

Message:

fix multi-level exit code (labeled break and continue)

File:

• src/ControlStruct/MLEMutator.cc (modified) (7 diffs)

src/ControlStruct/MLEMutator.cc

@@ -10 +10 @@
 // Created On       : Mon May 18 07:44:20 2015
 // Last Modified By : Rob Schluntz
-// Last Modified On : Tue Jun 02 13:43:01 2015
-// Update Count     : 92
+// Last Modified On : Wed Jun 03 15:09:27 2015
+// Update Count     : 170
 //
 
@@ -19 +19 @@
 #include "MLEMutator.h"
 #include "SynTree/Statement.h"
+#include "SynTree/Expression.h"
 
 namespace ControlStruct {
@@ -26 +27 @@
         }
 
-        CompoundStmt* MLEMutator::mutate( CompoundStmt *cmpndStmt ) {
-                bool labeledBlock = false;
-                if ( !(cmpndStmt->get_labels().empty()) ) {
-                        labeledBlock = true;
-                        enclosingBlocks.push_back( Entry( cmpndStmt ) );
-                } // if
-
-                // a child statement may set the break label
-                // - if they do, attach it to the next statement
-                std::list< Statement * > &kids = cmpndStmt->get_kids();
+        // break labels have to come after the statement they break out of, 
+        // so mutate a statement, then if they inform us through the breakLabel field
+        // tha they need a place to jump to on a break statement, add the break label 
+        // to the body of statements
+        void MLEMutator::fixBlock( std::list< Statement * > &kids ) {
                 for ( std::list< Statement * >::iterator k = kids.begin(); k != kids.end(); k++ ) {
                         *k = (*k)->acceptMutator(*this);
@@ -51 +47 @@
                         } // if
                 } // for
+        }
+
+        CompoundStmt* MLEMutator::mutate( CompoundStmt *cmpndStmt ) {
+                bool labeledBlock = !(cmpndStmt->get_labels().empty());
+                if ( labeledBlock ) {
+                        Label brkLabel = generator->newLabel();
+                        enclosingBlocks.push_back( Entry( cmpndStmt, brkLabel ) );
+                } // if
+
+                // a child statement may set the break label
+                // - if they do, attach it to the next statement
+                std::list< Statement * > &kids = cmpndStmt->get_kids();
+                fixBlock( kids );
 
                 if ( labeledBlock ) {
                         assert( ! enclosingBlocks.empty() );
-                        if ( ! enclosingBlocks.back().get_breakExit().empty() ) {
-                                set_breakLabel( enclosingBlocks.back().get_breakExit() );
+                        if ( ! enclosingBlocks.back().useBreakExit().empty() ) {
+                                set_breakLabel( enclosingBlocks.back().useBreakExit() );
                         }
                         enclosingBlocks.pop_back();
@@ -63 +72 @@
         }
 
-        Statement *MLEMutator::mutate( WhileStmt *whileStmt ) {
-                enclosingLoops.push_back( Entry( whileStmt ) );
-                whileStmt->set_body ( whileStmt->get_body()->acceptMutator( *this ) );
-
+        template< typename LoopClass >
+        Statement *MLEMutator::handleLoopStmt( LoopClass *loopStmt ) {
+                // remember this as the most recent enclosing loop, then mutate 
+                // the body of the loop -- this will do SOMETHING with branch statements
+                // and will recursively do the same to nested loops
+                Label brkLabel = generator->newLabel("loopBreak");
+                Label contLabel = generator->newLabel("loopContinue");
+                enclosingLoops.push_back( Entry( loopStmt, brkLabel, contLabel ) );
+                loopStmt->set_body ( loopStmt->get_body()->acceptMutator( *this ) );
+
+                // sanity check that the enclosing loops have been popped correctly
                 Entry &e = enclosingLoops.back();
-                assert ( e == whileStmt );
-                whileStmt->set_body( mutateLoop( whileStmt->get_body(), e ) );
+                assert ( e == loopStmt );
+
+                // generate labels as needed
+                loopStmt->set_body( mutateLoop( loopStmt->get_body(), e ) );
                 enclosingLoops.pop_back();
 
-                return whileStmt;
-        }
-
-        Statement *MLEMutator::mutate( ForStmt *forStmt ) {
-                enclosingLoops.push_back( Entry( forStmt ) );
-                forStmt->set_body( maybeMutate( forStmt->get_body(), *this ) );
-
-                Entry &e = enclosingLoops.back();
-                assert ( e == forStmt );
-                forStmt->set_body( mutateLoop( forStmt->get_body(), e ) );
-                enclosingLoops.pop_back();
-
-                return forStmt;
+                return loopStmt;
+        }
+
+        Statement *MLEMutator::mutate( CaseStmt *caseStmt ) {
+                caseStmt->set_condition( maybeMutate( caseStmt->get_condition(), *this ) );
+                fixBlock( caseStmt->get_statements() );
+
+                return caseStmt;
+        }
+
+        template< typename SwitchClass >
+        Statement *MLEMutator::handleSwitchStmt( SwitchClass *switchStmt ) {
+                // generate a label for breaking out of a labeled switch 
+                Label brkLabel = generator->newLabel("switchBreak");
+                enclosingSwitches.push_back( Entry(switchStmt, brkLabel) );
+                mutateAll( switchStmt->get_branches(), *this ); 
+
+                Entry &e = enclosingSwitches.back();
+                assert ( e == switchStmt );
+
+                // only generate break label if labeled break is used
+                if (e.isBreakUsed()) {
+                        // for the purposes of keeping switch statements uniform (i.e. all statements that are 
+                        // direct children of a switch should be CastStmts), append the exit label + break to the 
+                        // last case statement; create a default case if there are no cases
+                        std::list< Statement * > &branches = switchStmt->get_branches();
+                        if ( branches.empty() ) {
+                                branches.push_back( CaseStmt::makeDefault() );
+                        }
+
+                        if ( CaseStmt * c = dynamic_cast< CaseStmt * >( branches.back() ) ) {
+                                std::list<Label> temp; temp.push_back( brkLabel );
+                                c->get_statements().push_back( new BranchStmt( temp, Label(""), BranchStmt::Break ) );
+                        } else assert(0); // as of this point, all branches of a switch are still CaseStmts
+                }
+
+                assert ( enclosingSwitches.back() == switchStmt );
+                enclosingSwitches.pop_back();
+                return switchStmt;
         }
 
@@ -118 +162 @@
                                         throw SemanticError("The target specified in the exit loop statement does not correspond to an enclosing control structure: " + originalTarget );
 
+                // what about exiting innermost block or switch???
                 if ( enclosingLoops.back() == (*check) )
                         return branchStmt;                              // exit the innermost loop (labels unnecessary)
 
-                Label newLabel;
+                // branch error checks, get the appropriate label name and create a goto
+                Label exitLabel;
                 switch ( branchStmt->get_type() ) {
                   case BranchStmt::Break:
-                                if ( check->get_breakExit() != "" ) {
-                                        newLabel = check->get_breakExit();
-                                } else {
-                                        newLabel = generator->newLabel();
-                                        check->set_breakExit( newLabel );
-                                } // if
+                                assert( check->useBreakExit() != "");
+                                exitLabel = check->useBreakExit();
                                 break;
                   case BranchStmt::Continue:
-                                if ( check->get_contExit() != "" ) {
-                                        newLabel = check->get_contExit();
-                                } else {
-                                        newLabel = generator->newLabel();
-                                        check->set_contExit( newLabel );
-                                } // if
+                                assert( check->useContExit() != "");
+                                exitLabel = check->useContExit();
                                 break;
                   default:
-                                return 0;                                       // shouldn't be here
+                                assert(0);                                      // shouldn't be here
                 } // switch
 
-                return new BranchStmt( std::list<Label>(), newLabel, BranchStmt::Goto );
-        }
-
-        template< typename SwitchClass >
-        Statement *handleSwitchStmt( SwitchClass *switchStmt, MLEMutator &mutator ) {
-                // set up some aliases so that the rest of the code isn't messy
-                typedef MLEMutator::Entry Entry;
-                LabelGenerator *generator = mutator.generator;
-                std::list< Entry > &enclosingSwitches = mutator.enclosingSwitches;
-
-                Label brkLabel = generator->newLabel();
-                enclosingSwitches.push_back( Entry(switchStmt, "", brkLabel) );
-                mutateAll( switchStmt->get_branches(), mutator ); 
-                {
-                        // check if this is necessary (if there is a break to this point, otherwise do not generate
-
-                        // for the purposes of keeping switch statements uniform (i.e. all statements that are 
-                        // direct children of a switch should be CastStmts), append the exit label + break to the 
-                        // last case statement; create a default case if there are no cases
-                        std::list< Statement * > &branches = switchStmt->get_branches();
-                        if ( branches.empty() ) {
-                                branches.push_back( CaseStmt::makeDefault() );
-                        }
-
-                        if ( CaseStmt * c = dynamic_cast< CaseStmt * >( branches.back() ) ) {
-                                std::list<Label> temp; temp.push_back( brkLabel );
-                                c->get_statements().push_back( new BranchStmt( temp, Label(""), BranchStmt::Break ) );
-                        } else assert(0);
-                }
-                assert ( enclosingSwitches.back() == switchStmt );
-                enclosingSwitches.pop_back();
-                return switchStmt;
-        }
-
-        Statement *MLEMutator::mutate( SwitchStmt *switchStmt ) {
-                return handleSwitchStmt( switchStmt, *this );
-        }
-
-        Statement *MLEMutator::mutate( ChooseStmt *switchStmt ) {
-                return handleSwitchStmt( switchStmt, *this );           
+                return new BranchStmt( std::list<Label>(), exitLabel, BranchStmt::Goto );
         }
 
@@ -193 +192 @@
                 } // if
 
-                Label endLabel = e.get_contExit();
-
-                if ( e.get_breakExit() != "" ) {
-                        if ( endLabel == "" ) endLabel = generator->newLabel();
-                        // check for whether this label is used or not, so as to not generate extraneous gotos
-                        if (e.breakExitUsed)
-                                newBody->get_kids().push_back( new BranchStmt( std::list< Label >(), endLabel, BranchStmt::Goto ) );
-                        // xxx
-                        //std::list< Label > ls; ls.push_back( e.get_breakExit() );
-                        set_breakLabel( e.get_breakExit() );
-                        //newBody->get_kids().push_back( new BranchStmt( ls, "", BranchStmt::Break ) );
-                } // if
-
-                if ( e.get_breakExit() != "" || e.get_contExit() != "" ) {
-                        if (dynamic_cast< NullStmt *>( newBody->get_kids().back() ))
-                                newBody->get_kids().back()->get_labels().push_back( endLabel );
-                        else {
-                                std::list < Label > ls; ls.push_back( endLabel );
-                                newBody->get_kids().push_back( new NullStmt( ls ) );
-                        } // if
-                } // if
+                // only generate these when needed
+
+                if ( e.isContUsed() ) {
+                        // continue label goes in the body as the last statement
+                        std::list< Label > labels; labels.push_back( e.useContExit() );
+                        newBody->get_kids().push_back( new NullStmt( labels ) );                        
+                }
+
+                if ( e.isBreakUsed() ) {
+                        // break label goes after the loop -- it'll get set by the 
+                        // outer mutator if we do this
+                        set_breakLabel( e.useBreakExit() );                     
+                }
 
                 return newBody;
         }
 
-        //*** Entry's methods - ensure these labels can be set at most once
-        void MLEMutator::Entry::set_contExit( Label l ) {
-                assert ( contExit == "" || contExit == l );
-                contExit = l;
-        }
-
-        void MLEMutator::Entry::set_breakExit( Label l ) {
-                assert ( breakExit == "" || breakExit == l );
-                breakExit = l;
-        }
+        Statement *MLEMutator::mutate( WhileStmt *whileStmt ) {
+                return handleLoopStmt( whileStmt );
+        }
+
+        Statement *MLEMutator::mutate( ForStmt *forStmt ) {
+                return handleLoopStmt( forStmt );
+        }
+
+        Statement *MLEMutator::mutate( SwitchStmt *switchStmt ) {
+                return handleSwitchStmt( switchStmt );
+        }
+
+        Statement *MLEMutator::mutate( ChooseStmt *switchStmt ) {
+                return handleSwitchStmt( switchStmt );          
+        }
+
 } // namespace ControlStruct