Changeset b7fd9daf

Timestamp:

Nov 10, 2021, 7:47:45 PM (3 years ago)

Author:

Fangren Yu <f37yu@…>

Branches:

ADT, ast-experimental, enum, forall-pointer-decay, master, pthread-emulation, qualifiedEnum

Children:

3249dd8b

Parents:

1622af5 (diff), f95634e (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge branch 'new-ast-unique-expr'

Location:

src

Files:

• AST/Convert.cpp (modified) (1 diff)
• AST/Copy.hpp (modified) (2 diffs)
• AST/Expr.hpp (modified) (1 diff)
• Tuples/TupleExpansionNew.cpp (modified) (2 diffs)
• Tuples/Tuples.h (modified) (1 diff)
• main.cc (modified) (2 diffs)

src/AST/Convert.cpp

@@ -1041 +1041 @@
 
         const ast::Expr * visit( const ast::StmtExpr * node ) override final {
-                auto stmts = node->stmts;
-                // disable sharing between multiple StmtExprs explicitly.
-                // this should no longer be true.
-
                 auto rslt = new StmtExpr(
-                        get<CompoundStmt>().accept1(stmts)
+                        get<CompoundStmt>().accept1(node->stmts)
                 );
 
                 rslt->returnDecls = get<ObjectDecl>().acceptL(node->returnDecls);
                 rslt->dtors       = get<Expression>().acceptL(node->dtors);
-                if (node->resultExpr) {
-                        // this MUST be found by children visit
-                        rslt->resultExpr  = strict_dynamic_cast<ExprStmt *>(readonlyCache.at(node->resultExpr));
-                }
+
+                // is this even used after convert?
+                //if (tmp->resultExpr) {
+                //      // this MUST be found by children visit
+                //      rslt->resultExpr  = strict_dynamic_cast<ExprStmt *>(readonlyCache.at(tmp->resultExpr));
+                //}
 
                 auto expr = visitBaseExpr( node, rslt );

src/AST/Copy.hpp

@@ -88 +88 @@
         }
 
+        void postvisit( const StmtExpr * node ) {
+                readonlyInsert( &node->resultExpr );
+        }
+
         void postvisit( const MemberExpr * node ) {
                 readonlyInsert( &node->member );
@@ -122 +126 @@
 node_t * deepCopy( const node_t * localRoot ) {
         Pass< DeepCopyCore > dc;
-        node_t const * newRoot = localRoot->accept( dc );
+        node_t const * newRoot = strict_dynamic_cast<node_t const*>(localRoot->accept( dc ));
         dc.core.readonlyUpdates();
         return const_cast< node_t * >( newRoot );

src/AST/Expr.hpp

@@ -767 +767 @@
 
 /// An expression which must only be evaluated once
-class UniqueExpr final : public Expr {
+class 
+UniqueExpr final : public Expr {
         static unsigned long long nextId;
 public:

src/Tuples/TupleExpansionNew.cpp

@@ -21 +21 @@
                 void previsit( const ast::UntypedMemberExpr * ) { visit_children = false; }
         const ast::Expr * postvisit( const ast::UntypedMemberExpr * memberExpr );
+        };
+        struct UniqueExprExpander final : public ast::WithDeclsToAdd<> {
+                const ast::Expr * postvisit( const ast::UniqueExpr * unqExpr );
+                std::map< int, ast::ptr<ast::Expr> > decls; // not vector, because order added may not be increasing order
         };
 } // namespace
@@ -66 +70 @@
         }
 } // namespace
+
+void expandUniqueExpr( ast::TranslationUnit & translationUnit ) {
+        ast::Pass< UniqueExprExpander >::run( translationUnit );
+}
+
+namespace {
+        const ast::Expr * UniqueExprExpander::postvisit( const ast::UniqueExpr * unqExpr ) {
+                const CodeLocation loc = unqExpr->location;
+                const int id = unqExpr->id;
+
+                // on first time visiting a unique expr with a particular ID, generate the expression that replaces all UniqueExprs with that ID,
+                // and lookup on subsequent hits. This ensures that all unique exprs with the same ID reference the same variable.
+                if ( ! decls.count( id ) ) {
+                        ast::ptr< ast::Expr > assignUnq;
+                        const ast::VariableExpr * var = unqExpr->var;
+                        if ( unqExpr->object ) {
+                                // an object was generated to represent this unique expression -- it should be added to the list of declarations now
+                                declsToAddBefore.push_back( unqExpr->object.as< ast::Decl >() );
+                                // deep copy required due to unresolved issues with UniqueExpr
+                                assignUnq = ast::UntypedExpr::createAssign( loc, var, unqExpr->expr );
+                        } else {
+                                const auto commaExpr = unqExpr->expr.strict_as< ast::CommaExpr >();
+                                assignUnq = commaExpr->arg1;
+                        }
+                        auto finished = new ast::ObjectDecl( loc, toString( "_unq", id, "_finished_" ), new ast::BasicType( ast::BasicType::Kind::Bool ),
+                                new ast::SingleInit( loc, ast::ConstantExpr::from_int( loc, 0 ) ), {}, ast::Linkage::Cforall );
+                        declsToAddBefore.push_back( finished );
+                        // (finished ? _unq_expr_N : (_unq_expr_N = <unqExpr->get_expr()>, finished = 1, _unq_expr_N))
+                        // This pattern ensures that each unique expression is evaluated once, regardless of evaluation order of the generated C code.
+                        auto assignFinished = ast::UntypedExpr::createAssign( loc, new ast::VariableExpr( loc, finished ),
+                                ast::ConstantExpr::from_int( loc, 1 ) );
+                        auto condExpr = new ast::ConditionalExpr( loc, new ast::VariableExpr( loc, finished ), var,
+                                new ast::CommaExpr( loc, new ast::CommaExpr( loc, assignUnq, assignFinished ), var ) );
+                        condExpr->result = var->result;
+                        condExpr->env = unqExpr->env;
+                        decls[id] = condExpr;
+                }
+                //delete unqExpr;
+                return ast::deepCopy(decls[id].get());
+        }
+} // namespace
 } // namespace Tuples

src/Tuples/Tuples.h

@@ -46 +46 @@
         /// replaces UniqueExprs with a temporary variable and one call
         void expandUniqueExpr( std::list< Declaration * > & translationUnit );
+        void expandUniqueExpr( ast::TranslationUnit & translationUnit );
 
         /// returns VoidType if any of the expressions have Voidtype, otherwise TupleType of the Expression result types

src/main.cc

@@ -381 +381 @@
                         PASS( "Fix Init", InitTweak::fix(transUnit, buildingLibrary()));
 
+                        // fix ObjectDecl - replaces ConstructorInit nodes
+                        if ( ctorinitp ) {
+                                dump( move( transUnit ) );
+                                return EXIT_SUCCESS;
+                        } // if
+
+                        // Currently not working due to unresolved issues with UniqueExpr
+                        PASS( "Expand Unique Expr", Tuples::expandUniqueExpr( transUnit ) ); // xxx - is this the right place for this? want to expand ASAP so tha, sequent passes don't need to worry about double-visiting a unique expr - needs to go after InitTweak::fix so that copy constructed return declarations are reused
                         translationUnit = convert( move( transUnit ) );
                 } else {
@@ -435 +443 @@
 
                         PASS( "Fix Init", InitTweak::fix( translationUnit, buildingLibrary() ) );
+
+                        // fix ObjectDecl - replaces ConstructorInit nodes
+                        if ( ctorinitp ) {
+                                dump ( translationUnit );
+                                return EXIT_SUCCESS;
+                        } // if
+
+                        PASS( "Expand Unique Expr", Tuples::expandUniqueExpr( translationUnit ) ); // xxx - is this the right place for this? want to expand ASAP so tha, sequent passes don't need to worry about double-visiting a unique expr - needs to go after InitTweak::fix so that copy constructed return declarations are reused
                 }
-
-                // fix ObjectDecl - replaces ConstructorInit nodes
-                if ( ctorinitp ) {
-                        dump ( translationUnit );
-                        return EXIT_SUCCESS;
-                } // if
-
-                PASS( "Expand Unique Expr", Tuples::expandUniqueExpr( translationUnit ) ); // xxx - is this the right place for this? want to expand ASAP so tha, sequent passes don't need to worry about double-visiting a unique expr - needs to go after InitTweak::fix so that copy constructed return declarations are reused
 
                 PASS( "Translate Tries" , ControlStruct::translateTries( translationUnit ) );