Changeset 5f98ce5 for src/InitTweak

Timestamp:

Jul 19, 2016, 7:09:30 PM (8 years ago)

Author:

Rob Schluntz <rschlunt@…>

Branches:

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

Children:

40e636a

Parents:

2be1023

Message:

hoist non-constexpr array dimension into const variable in case of side effects

Location:

src/InitTweak

Files:

• FixGlobalInit.cc (modified) (1 diff)
• GenInit.cc (modified) (6 diffs)
• InitTweak.h (modified) (1 diff)

src/InitTweak/FixGlobalInit.cc

@@ -79 +79 @@
                 bool isConstExpr;
         };
+
+        bool isConstExpr( Expression * expr ) {
+                if ( expr ) {
+                        ConstExprChecker checker;
+                        expr->accept( checker );
+                        return checker.isConstExpr;
+                }
+                return true;
+        }
 
         bool isConstExpr( Initializer * init ) {

src/InitTweak/GenInit.cc

@@ -26 +26 @@
 #include "SymTab/Autogen.h"
 #include "GenPoly/PolyMutator.h"
+#include "GenPoly/DeclMutator.h"
 
 namespace InitTweak {
@@ -55 +56 @@
           public:
                 /// create constructor and destructor statements for object declarations.
-                /// Destructors are inserted directly into the code, whereas constructors
-                /// will be added in after the resolver has run so that the initializer expression
-                /// is only removed if a constructor is found
+                /// the actual call statements will be added in after the resolver has run
+                /// so that the initializer expression is only removed if a constructor is found
+                /// and the same destructor call is inserted in all of the appropriate locations.
                 static void generateCtorDtor( std::list< Declaration * > &translationUnit );
 
@@ -64 +65 @@
                 virtual DeclarationWithType * mutate( ObjectDecl * );
                 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl );
-                virtual Declaration* mutate( StructDecl *aggregateDecl );
-                virtual Declaration* mutate( UnionDecl *aggregateDecl );
-                virtual Declaration* mutate( EnumDecl *aggregateDecl );
-                virtual Declaration* mutate( TraitDecl *aggregateDecl );
-                virtual TypeDecl* mutate( TypeDecl *typeDecl );
-                virtual Declaration* mutate( TypedefDecl *typeDecl );
-
-                virtual Type * mutate( FunctionType *funcType );
+                // should not traverse into any of these declarations to find objects
+                // that need to be constructed or destructed
+                virtual Declaration* mutate( StructDecl *aggregateDecl ) { return aggregateDecl; }
+                virtual Declaration* mutate( UnionDecl *aggregateDecl ) { return aggregateDecl; }
+                virtual Declaration* mutate( EnumDecl *aggregateDecl ) { return aggregateDecl; }
+                virtual Declaration* mutate( TraitDecl *aggregateDecl ) { return aggregateDecl; }
+                virtual TypeDecl* mutate( TypeDecl *typeDecl ) { return typeDecl; }
+                virtual Declaration* mutate( TypedefDecl *typeDecl ) { return typeDecl; }
+
+                virtual Type * mutate( FunctionType *funcType ) { return funcType; }
 
           protected:
@@ -77 +80 @@
         };
 
+        class HoistArrayDimension : public GenPoly::DeclMutator {
+          public:
+                typedef GenPoly::DeclMutator Parent;
+
+                /// hoist dimension from array types in object declaration so that it uses a single
+                /// const variable of type size_t, so that side effecting array dimensions are only
+                /// computed once.
+                static void hoistArrayDimension( std::list< Declaration * > & translationUnit );
+
+          private:
+                DeclarationWithType * mutate( ObjectDecl * objectDecl );
+                // should not traverse into any of these declarations to find objects
+                // that need to be constructed or destructed
+                virtual Declaration* mutate( StructDecl *aggregateDecl ) { return aggregateDecl; }
+                virtual Declaration* mutate( UnionDecl *aggregateDecl ) { return aggregateDecl; }
+                virtual Declaration* mutate( EnumDecl *aggregateDecl ) { return aggregateDecl; }
+                virtual Declaration* mutate( TraitDecl *aggregateDecl ) { return aggregateDecl; }
+                virtual TypeDecl* mutate( TypeDecl *typeDecl ) { return typeDecl; }
+                virtual Declaration* mutate( TypedefDecl *typeDecl ) { return typeDecl; }
+
+                virtual Type* mutate( FunctionType *funcType ) { return funcType; }
+
+                void hoist( Type * type );
+
+                DeclarationNode::StorageClass storageclass = DeclarationNode::NoStorageClass;
+        };
+
         void genInit( std::list< Declaration * > & translationUnit ) {
                 ReturnFixer::makeReturnTemp( translationUnit );
+                HoistArrayDimension::hoistArrayDimension( translationUnit );
                 CtorDtor::generateCtorDtor( translationUnit );
         }
@@ -124 +155 @@
         }
 
+        void HoistArrayDimension::hoistArrayDimension( std::list< Declaration * > & translationUnit ) {
+                HoistArrayDimension hoister;
+                mutateAll( translationUnit, hoister );
+        }
+
+        DeclarationWithType * HoistArrayDimension::mutate( ObjectDecl * objectDecl ) {
+                storageclass = objectDecl->get_storageClass();
+                DeclarationWithType * temp = Parent::mutate( objectDecl );
+                hoist( objectDecl->get_type() );
+                storageclass = DeclarationNode::NoStorageClass;
+                return temp;
+        }
+
+        void HoistArrayDimension::hoist( Type * type ) {
+                static UniqueName dimensionName( "_array_dim" );
+                if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
+                        if ( ! arrayType->get_dimension() ) return; // xxx - recursive call to hoist?
+
+                        // don't need to hoist dimension if it's a constexpr - only need to if there's potential
+                        // for side effects.
+                        if ( isConstExpr( arrayType->get_dimension() ) ) return;
+
+                        ObjectDecl * arrayDimension = new ObjectDecl( dimensionName.newName(), storageclass, LinkageSpec::C, 0, SymTab::SizeType->clone(), new SingleInit( arrayType->get_dimension() ) );
+                        arrayDimension->get_type()->set_isConst( true );
+
+                        arrayType->set_dimension( new VariableExpr( arrayDimension ) );
+                        addDeclaration( arrayDimension );
+
+                        hoist( arrayType->get_base() );
+                        return;
+                }
+        }
 
         void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) {
@@ -203 +266 @@
                 return functionDecl;
         }
-
-        // should not traverse into any of these declarations to find objects
-        // that need to be constructed or destructed
-        Declaration* CtorDtor::mutate( StructDecl *aggregateDecl ) { return aggregateDecl; }
-        Declaration* CtorDtor::mutate( UnionDecl *aggregateDecl ) { return aggregateDecl; }
-        Declaration* CtorDtor::mutate( EnumDecl *aggregateDecl ) { return aggregateDecl; }
-        Declaration* CtorDtor::mutate( TraitDecl *aggregateDecl ) { return aggregateDecl; }
-        TypeDecl* CtorDtor::mutate( TypeDecl *typeDecl ) { return typeDecl; }
-        Declaration* CtorDtor::mutate( TypedefDecl *typeDecl ) { return typeDecl; }
-        Type* CtorDtor::mutate( FunctionType *funcType ) { return funcType; }
-
 } // namespace InitTweak
 

src/InitTweak/InitTweak.h

@@ -54 +54 @@
   /// returns the argument if it is a PointerType or ArrayType, else returns NULL
   Type * isPointerType( Type * );
+
+  /// returns true if expr is trivially a compile-time constant
+  bool isConstExpr( Expression * expr );
+  bool isConstExpr( Initializer * init );
 } // namespace