When an interface I1 in an imported Go package has an unexported
method, and is then embedded into another interface I2, in a different
package, that has other methods, and a type T2 is converted to I2, the
Go frontend failed to ever define the required interface method table.
Naturally T2 must implement the unexported method, and must therefore
either be defined in the same package as I1, or embed a type from that
package. In this case the compiler was assuming that that package
would define the interface method table, but of course, since I2 was
not defined in that package, that did not happen.
The fix is to only assume that the interface method table will be
defined elsewhere in the case where T2 and I2 are defined in the same
package. The compiler ensures that all such interface method tables
are created, in Gogo::build_interface_method_tables. This requires
knowing the package in which an interface type is defined, a simple
tweak to the importer.
Testing this revealed that the special case for stub methods created
for the embedded unexported methods of T2 needs to be done for
function declarations as it currently is for function definitions,
sothat the newly created interface method tables use the correct name.
Testing that revealed that the code to determine the pkgpath symbolfor
such stub methods was wrong. It assumed that one could call
pkgpath_for_symbol on the pkgpath to get the pkgpath symbol. Would
that it twere so simple. Instead, add a function to look up the
package, which must be known, and fetch the pkgpath symbol.
The test for this is https://golang.org/cl/45085.
Bootstrapped and ran Go testsuite on x86_64-pc-linux-gnu. Committed
to mainline.
Ian
Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE (revision 248994)
+++ gcc/go/gofrontend/MERGE (working copy)
@@ -1,4 +1,4 @@
-eaf4afbabcd91df55d31955500b6db55b07f6de5
+4b857cde45939f0e9f3cf89b9e347b6f6ebe0f8f
The first line of this file holds the git revision number of the last
merge done from the gofrontend repository.
Index: gcc/go/gofrontend/expressions.cc
===================================================================
--- gcc/go/gofrontend/expressions.cc (revision 248934)
+++ gcc/go/gofrontend/expressions.cc (working copy)
@@ -15430,27 +15430,32 @@ Interface_mtable_expression::do_get_back
+ "__"
+ this->type_->mangled_name(gogo));
- // See whether this interface has any hidden methods.
- bool has_hidden_methods = false;
- for (Typed_identifier_list::const_iterator p = interface_methods->begin();
- p != interface_methods->end();
- ++p)
+ // Set is_public if we are converting a named type to an interface
+ // type that is defined in the same package as the named type, and
+ // the interface has hidden methods. In that case the interface
+ // method table will be defined by the package that defines the
+ // types.
+ bool is_public = false;
+ if (this->type_->named_type() != NULL
+ && (this->type_->named_type()->named_object()->package()
+ == this->itype_->package()))
{
- if (Gogo::is_hidden_name(p->name()))
+ for (Typed_identifier_list::const_iterator p =
interface_methods->begin();
+ p != interface_methods->end();
+ ++p)
{
- has_hidden_methods = true;
- break;
+ if (Gogo::is_hidden_name(p->name()))
+ {
+ is_public = true;
+ break;
+ }
}
}
- // We already know that the named type is convertible to the
- // interface. If the interface has hidden methods, and the named
- // type is defined in a different package, then the interface
- // conversion table will be defined by that other package.
- if (has_hidden_methods
- && this->type_->named_type() != NULL
+ if (is_public
&& this->type_->named_type()->named_object()->package() != NULL)
{
+ // The interface conversion table is defined elsewhere.
Btype* btype = this->type()->get_backend(gogo);
std::string asm_name(go_selectively_encode_id(mangled_name));
this->bvar_ =
@@ -15517,7 +15522,6 @@ Interface_mtable_expression::do_get_back
Bexpression* ctor =
gogo->backend()->constructor_expression(btype, ctor_bexprs, loc);
- bool is_public = has_hidden_methods && this->type_->named_type() != NULL;
std::string asm_name(go_selectively_encode_id(mangled_name));
this->bvar_ = gogo->backend()->immutable_struct(mangled_name, asm_name,
false,
!is_public, btype, loc);
Index: gcc/go/gofrontend/gogo.cc
===================================================================
--- gcc/go/gofrontend/gogo.cc (revision 248394)
+++ gcc/go/gofrontend/gogo.cc (working copy)
@@ -1688,6 +1688,16 @@ Gogo::register_package(const std::string
return package;
}
+// Return the pkgpath symbol for a package, given the pkgpath.
+
+std::string
+Gogo::pkgpath_symbol_for_package(const std::string& pkgpath)
+{
+ Packages::iterator p = this->packages_.find(pkgpath);
+ go_assert(p != this->packages_.end());
+ return p->second->pkgpath_symbol();
+}
+
// Start compiling a function.
Named_object*
@@ -5418,8 +5428,8 @@ Function::get_or_make_decl(Gogo* gogo, N
// use the pkgpath of the imported package to avoid
// a possible name collision. See bug478 for a test
// case.
- pkgpath = Gogo::hidden_name_pkgpath(no->name());
- pkgpath = Gogo::pkgpath_for_symbol(pkgpath);
+ std::string p = Gogo::hidden_name_pkgpath(no->name());
+ pkgpath = gogo->pkgpath_symbol_for_package(p);
}
asm_name = pkgpath;
@@ -5514,8 +5524,19 @@ Function_declaration::get_or_make_decl(G
if (this->asm_name_.empty())
{
asm_name = (no->package() == NULL
- ? gogo->pkgpath_symbol()
- : no->package()->pkgpath_symbol());
+ ? gogo->pkgpath_symbol()
+ : no->package()->pkgpath_symbol());
+ if (this->fntype_->is_method()
+ && Gogo::is_hidden_name(no->name())
+ && Gogo::hidden_name_pkgpath(no->name()) != gogo->pkgpath())
+ {
+ // This is a method created for an unexported method of
+ // an imported embedded type. Use the pkgpath of the
+ // imported package. This matches code in
+ // Function::get_or_make_decl, above.
+ std::string p = Gogo::hidden_name_pkgpath(no->name());
+ asm_name = gogo->pkgpath_symbol_for_package(p);
+ }
asm_name.append(1, '.');
asm_name.append(Gogo::unpack_hidden_name(no->name()));
if (this->fntype_->is_method())
Index: gcc/go/gofrontend/gogo.h
===================================================================
--- gcc/go/gofrontend/gogo.h (revision 248081)
+++ gcc/go/gofrontend/gogo.h (working copy)
@@ -362,6 +362,10 @@ class Gogo
register_package(const std::string& pkgpath,
const std::string& pkgpath_symbol, Location);
+ // Look up a package by pkgpath, and return its pkgpath_symbol.
+ std::string
+ pkgpath_symbol_for_package(const std::string&);
+
// Start compiling a function. ADD_METHOD_TO_TYPE is true if a
// method function should be added to the type of its receiver.
Named_object*
Index: gcc/go/gofrontend/types.cc
===================================================================
--- gcc/go/gofrontend/types.cc (revision 248528)
+++ gcc/go/gofrontend/types.cc (working copy)
@@ -9816,7 +9816,9 @@ Interface_type::do_import(Import* imp)
methods = NULL;
}
- return Type::make_interface_type(methods, imp->location());
+ Interface_type* ret = Type::make_interface_type(methods, imp->location());
+ ret->package_ = imp->package();
+ return ret;
}
// Make an interface type.
Index: gcc/go/gofrontend/types.h
===================================================================
--- gcc/go/gofrontend/types.h (revision 248528)
+++ gcc/go/gofrontend/types.h (working copy)
@@ -2854,9 +2854,9 @@ class Interface_type : public Type
Interface_type(Typed_identifier_list* methods, Location location)
: Type(TYPE_INTERFACE),
parse_methods_(methods), all_methods_(NULL), location_(location),
- interface_btype_(NULL), bmethods_(NULL), assume_identical_(NULL),
- methods_are_finalized_(false), bmethods_is_placeholder_(false),
- seen_(false)
+ package_(NULL), interface_btype_(NULL), bmethods_(NULL),
+ assume_identical_(NULL), methods_are_finalized_(false),
+ bmethods_is_placeholder_(false), seen_(false)
{ go_assert(methods == NULL || !methods->empty()); }
// The location where the interface type was defined.
@@ -2864,6 +2864,12 @@ class Interface_type : public Type
location() const
{ return this->location_; }
+ // The package where the interface type was defined. Returns NULL
+ // for the package currently being compiled.
+ Package*
+ package() const
+ { return this->package_; }
+
// Return whether this is an empty interface.
bool
is_empty() const
@@ -3008,6 +3014,9 @@ class Interface_type : public Type
Typed_identifier_list* all_methods_;
// The location where the interface was defined.
Location location_;
+ // The package where the interface was defined. This is NULL for
+ // the package being compiled.
+ Package* package_;
// The backend representation of this type during backend conversion.
Btype* interface_btype_;
// The backend representation of the pointer to the method table.
