Changeset f5c3b6c for src/InitTweak

Timestamp:

Nov 8, 2017, 10:58:35 AM (6 years ago)

Author:

Rob Schluntz <rschlunt@…>

Branches:

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

Children:

0fe4e62

Parents:

d06c808

Message:

Use fake bitwise-assignment function when generating copy constructor calls.

This is change prevents assignment calls from being resolved incorrectly, but is an imperfect fix. Ideally this function could exist somewhere as a real function that the resolver never chooses.

Location:

src/InitTweak

Files:

• FixInit.cc (modified) (4 diffs)
• InitTweak.cc (modified) (2 diffs)
• InitTweak.h (modified) (1 diff)

src/InitTweak/FixInit.cc

@@ -393 +393 @@
                         if ( skipCopyConstruct( result ) ) return; // skip certain non-copyable types
 
-                        // type may involve type variables, so apply type substitution to get temporary variable's actual type.
+                        // type may involve type variables, so apply type substitution to get temporary variable's actual type,
+                        // since result type may not be substituted (e.g., if the type does not appear in the parameter list)
                         // Use applyFree so that types bound in function pointers are not substituted, e.g. in forall(dtype T) void (*)(T).
-                        result = result->clone();
                         env->applyFree( result );
                         ObjectDecl * tmp = ObjectDecl::newObject( "__tmp", result, nullptr );
@@ -570 +570 @@
 
                         if ( returnDecl ) {
-                                UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
-                                assign->get_args().push_back( new VariableExpr( returnDecl ) );
-                                assign->get_args().push_back( callExpr );
-                                // know the result type of the assignment is the type of the LHS (minus the pointer), so
-                                // add that onto the assignment expression so that later steps have the necessary information
-                                assign->set_result( returnDecl->get_type()->clone() );
-
+                                ApplicationExpr * assign = createBitwiseAssignment( new VariableExpr( returnDecl ), callExpr );
                                 Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
                                 // move env from callExpr to retExpr
@@ -1161 +1155 @@
                         assert( ctorExpr->result && ctorExpr->get_result()->size() == 1 );
 
-                        // xxx - ideally we would reuse the temporary generated from the copy constructor passes from within firstArg if it exists and not generate a temporary if it's unnecessary.
-                        ObjectDecl * tmp = ObjectDecl::newObject( tempNamer.newName(), ctorExpr->get_result()->clone(), nullptr );
-                        declsToAddBefore.push_back( tmp );
-
                         // xxx - this can be TupleAssignExpr now. Need to properly handle this case.
                         ApplicationExpr * callExpr = strict_dynamic_cast< ApplicationExpr * > ( ctorExpr->get_callExpr() );
@@ -1170 +1160 @@
                         ctorExpr->set_callExpr( nullptr );
                         ctorExpr->set_env( nullptr );
+
+                        // xxx - ideally we would reuse the temporary generated from the copy constructor passes from within firstArg if it exists and not generate a temporary if it's unnecessary.
+                        ObjectDecl * tmp = ObjectDecl::newObject( tempNamer.newName(), callExpr->args.front()->result->clone(), nullptr );
+                        declsToAddBefore.push_back( tmp );
                         delete ctorExpr;
 

src/InitTweak/InitTweak.cc

@@ -12 +12 @@
 #include "Parser/LinkageSpec.h"    // for Spec, isBuiltin, Intrinsic
 #include "ResolvExpr/typeops.h"    // for typesCompatibleIgnoreQualifiers
+#include "SymTab/Autogen.h"
 #include "SymTab/Indexer.h"        // for Indexer
 #include "SynTree/Attribute.h"     // for Attribute
@@ -523 +524 @@
         }
 
+        ApplicationExpr * createBitwiseAssignment( Expression * dst, Expression * src ) {
+                static FunctionDecl * assign = nullptr;
+                if ( ! assign ) {
+                        // temporary? Generate a fake assignment operator to represent bitwise assignments.
+                        // This operator could easily exist as a real function, but it's tricky because nothing should resolve to this function.
+                        TypeDecl * td = new TypeDecl( "T", noStorageClasses, nullptr, TypeDecl::Dtype, true );
+                        assign = new FunctionDecl( "?=?", noStorageClasses, LinkageSpec::Intrinsic, SymTab::genAssignType( new TypeInstType( noQualifiers, td->name, td ) ), nullptr );
+                }
+                if ( dynamic_cast< ReferenceType * >( dst->result ) ) {
+                        dst = new AddressExpr( dst );
+                } else {
+                        dst = new CastExpr( dst, new ReferenceType( noQualifiers, dst->result->clone() ) );
+                }
+                if ( dynamic_cast< ReferenceType * >( src->result ) ) {
+                        src = new CastExpr( src, new ReferenceType( noQualifiers, src->result->stripReferences()->clone() ) );
+                }
+                return new ApplicationExpr( VariableExpr::functionPointer( assign ), { dst, src } );
+        }
+
         class ConstExprChecker : public Visitor {
         public:

src/InitTweak/InitTweak.h

@@ -35 +35 @@
         /// returns the first parameter of a constructor/destructor/assignment function
         ObjectDecl * getParamThis( FunctionType * ftype );
+
+        /// generate a bitwise assignment operation.
+        ApplicationExpr * createBitwiseAssignment( Expression * dst, Expression * src );
 
         /// transform Initializer into an argument list that can be passed to a call expression