Changes in src/ResolvExpr/PtrsAssignable.cc [c6b4432:5bf3976]

File:

• src/ResolvExpr/PtrsAssignable.cc (modified) (1 diff)

src/ResolvExpr/PtrsAssignable.cc

@@ -19 +19 @@
 #include "AST/Type.hpp"
 #include "AST/TypeEnvironment.hpp"
+#include "Common/PassVisitor.h"
+#include "ResolvExpr/TypeEnvironment.h"  // for EqvClass, TypeEnvironment
+#include "SynTree/Type.h"                // for TypeInstType, Type, BasicType
+#include "SynTree/Visitor.h"             // for Visitor
+
 
 namespace ResolvExpr {
+        struct PtrsAssignable : public WithShortCircuiting {
+                PtrsAssignable( const Type * dest, const TypeEnvironment &env );
+
+                int get_result() const { return result; }
+
+                void previsit( const Type * ) { visit_children = false; }
+
+                void postvisit( const VoidType * voidType );
+                void postvisit( const BasicType * basicType );
+                void postvisit( const PointerType * pointerType );
+                void postvisit( const ArrayType * arrayType );
+                void postvisit( const FunctionType * functionType );
+                void postvisit( const StructInstType * inst );
+                void postvisit( const UnionInstType * inst );
+                void postvisit( const EnumInstType * inst );
+                void postvisit( const TraitInstType * inst );
+                void postvisit( const TypeInstType * inst );
+                void postvisit( const TupleType * tupleType );
+                void postvisit( const VarArgsType * varArgsType );
+                void postvisit( const ZeroType * zeroType );
+                void postvisit( const OneType * oneType );
+          private:
+                const Type * dest;
+                int result;
+                const TypeEnvironment &env;
+        };
+
+        int ptrsAssignable( const Type *src, const Type * dest, const TypeEnvironment &env ) {
+                // std::cerr << "assignable: " << src << " | " << dest << std::endl;
+                if ( const TypeInstType * destAsTypeInst = dynamic_cast< const TypeInstType* >( dest ) ) {
+                        if ( const EqvClass * eqvClass = env.lookup( destAsTypeInst->get_name() ) ) {
+                                return ptrsAssignable( src, eqvClass->type, env );
+                        } // if
+                } // if
+                if ( dynamic_cast< const VoidType* >( dest ) ) {
+                        // void * = T * for any T is unsafe
+                        // xxx - this should be safe, but that currently breaks the build
+                        return -1;
+                } else {
+                        PassVisitor<PtrsAssignable> ptrs( dest, env );
+                        src->accept( ptrs );
+                        return ptrs.pass.get_result();
+                } // if
+        }
+
+        PtrsAssignable::PtrsAssignable( const Type * dest, const TypeEnvironment &env ) : dest( dest ), result( 0 ), env( env ) {}
+
+        void PtrsAssignable::postvisit( const VoidType * ) {
+                // T * = void * is disallowed - this is a change from C, where any
+                // void * can be assigned or passed to a non-void pointer without a cast.
+        }
+
+        void PtrsAssignable::postvisit( const BasicType * ) {}
+        void PtrsAssignable::postvisit( const PointerType * ) {}
+        void PtrsAssignable::postvisit( const ArrayType * ) {}
+        void PtrsAssignable::postvisit( const FunctionType * ) {}
+
+        void PtrsAssignable::postvisit( const StructInstType * ) {}
+        void PtrsAssignable::postvisit( const UnionInstType * ) {}
+
+        void PtrsAssignable::postvisit( const EnumInstType * ) {
+                if ( dynamic_cast< const BasicType* >( dest ) ) {
+                        // int * = E *, etc. is safe. This isn't technically correct, as each
+                        // enum has one basic type that it is compatible with, an that type can
+                        // differ from enum to enum. Without replicating GCC's internal logic,
+                        // there is no way to know which type this particular enum is compatible
+                        // with, so punt on this for now.
+                        result = 1;
+                }
+        }
+
+        void PtrsAssignable::postvisit(  const TraitInstType * ) {}
+        void PtrsAssignable::postvisit( const TypeInstType * inst ) {
+                if ( const EqvClass * eqvClass = env.lookup( inst->name ) ) {
+                        if ( eqvClass->type ) {
+                                // T * = S * for any S depends on the type bound to T
+                                result = ptrsAssignable( eqvClass->type, dest, env );
+                        }
+                } // if
+        }
+
+        void PtrsAssignable::postvisit( const TupleType * ) {}
+        void PtrsAssignable::postvisit( const VarArgsType * ) {}
+        void PtrsAssignable::postvisit( const ZeroType * ) {}
+        void PtrsAssignable::postvisit( const OneType * ) {}
 
 // TODO: Get rid of the `_new` suffix when the old version is removed.