From d34f3a9312ea407812e1fab5ce3594ebe8139c0c Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Mon, 19 Jul 2021 16:47:05 -0700 Subject: [PATCH] compiler: avoid aliases in receiver types If a package declares a method on an alias type, the alias would be used in the export data. This would then trigger a compiler assertion on import: we should not be adding methods to aliases. Fix the problem by ensuring that receiver types do not use alias types. This seems preferable to consistently avoiding aliases in export data, as aliases can cross packages. And it's painful to try to patch this while writing the export data, as at that point all the types are known. Test case is https://golang.org/cl/335172. Fixes golang/go#47131 Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/335729 --- gcc/go/gofrontend/gogo.cc | 40 ++++++++++++++++++++++++++++++ gcc/go/gofrontend/gogo.h | 8 ++++++ gcc/go/gofrontend/types.cc | 51 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 99 insertions(+) diff --git a/gcc/go/gofrontend/gogo.cc b/gcc/go/gofrontend/gogo.cc index 93b54fd8c118..335982d2e804 100644 --- a/gcc/go/gofrontend/gogo.cc +++ b/gcc/go/gofrontend/gogo.cc @@ -5765,6 +5765,26 @@ Function::check_labels() const } } +// Set the receiver type. This is used to remove aliases. + +void +Function::set_receiver_type(Type* rtype) +{ + Function_type* oft = this->type_; + Typed_identifier* rec = new Typed_identifier(oft->receiver()->name(), + rtype, + oft->receiver()->location()); + Typed_identifier_list* parameters = NULL; + if (oft->parameters() != NULL) + parameters = oft->parameters()->copy(); + Typed_identifier_list* results = NULL; + if (oft->results() != NULL) + results = oft->results()->copy(); + Function_type* nft = Type::make_function_type(rec, parameters, results, + oft->location()); + this->type_ = nft; +} + // Swap one function with another. This is used when building the // thunk we use to call a function which calls recover. It may not // work for any other case. @@ -7287,6 +7307,26 @@ Function_declaration::set_nointerface() this->pragmas_ |= GOPRAGMA_NOINTERFACE; } +// Set the receiver type. This is used to remove aliases. + +void +Function_declaration::set_receiver_type(Type* rtype) +{ + Function_type* oft = this->fntype_; + Typed_identifier* rec = new Typed_identifier(oft->receiver()->name(), + rtype, + oft->receiver()->location()); + Typed_identifier_list* parameters = NULL; + if (oft->parameters() != NULL) + parameters = oft->parameters()->copy(); + Typed_identifier_list* results = NULL; + if (oft->results() != NULL) + results = oft->results()->copy(); + Function_type* nft = Type::make_function_type(rec, parameters, results, + oft->location()); + this->fntype_ = nft; +} + // Import an inlinable function. This is used for an inlinable // function whose body is recorded in the export data. Parse the // export data into a Block and create a regular function using that diff --git a/gcc/go/gofrontend/gogo.h b/gcc/go/gofrontend/gogo.h index f4155a29edb3..c49bc92b3e07 100644 --- a/gcc/go/gofrontend/gogo.h +++ b/gcc/go/gofrontend/gogo.h @@ -1724,6 +1724,10 @@ class Function set_is_referenced_by_inline() { this->is_referenced_by_inline_ = true; } + // Set the receiver type. This is used to remove aliases. + void + set_receiver_type(Type* rtype); + // Swap with another function. Used only for the thunk which calls // recover. void @@ -1990,6 +1994,10 @@ class Function_declaration set_is_on_inlinable_list() { this->is_on_inlinable_list_ = true; } + // Set the receiver type. This is used to remove aliases. + void + set_receiver_type(Type* rtype); + // Import the function body, creating a function. void import_function_body(Gogo*, Named_object*); diff --git a/gcc/go/gofrontend/types.cc b/gcc/go/gofrontend/types.cc index 7d4c47f1c426..ecf382302f70 100644 --- a/gcc/go/gofrontend/types.cc +++ b/gcc/go/gofrontend/types.cc @@ -10409,6 +10409,57 @@ Named_type::finalize_methods(Gogo* gogo) return; } + // Remove any aliases in the local method receiver types. + Bindings* methods = this->local_methods_; + if (methods != NULL) + { + for (Bindings::const_declarations_iterator p = + methods->begin_declarations(); + p != methods->end_declarations(); + ++p) + { + Named_object* no = p->second; + Function_type* fntype; + if (no->is_function()) + fntype = no->func_value()->type(); + else if (no->is_function_declaration()) + fntype = no->func_declaration_value()->type(); + else + { + go_assert(saw_errors()); + continue; + } + + Type* rtype = fntype->receiver()->type(); + bool is_pointer = false; + Type* pt = rtype->points_to(); + if (pt != NULL) + { + rtype = pt; + is_pointer = true; + } + if (rtype->named_type() != this) + { + if (rtype->unalias() != this) + { + go_assert(saw_errors()); + continue; + } + + rtype = this; + if (is_pointer) + rtype = Type::make_pointer_type(rtype); + + if (no->is_function()) + no->func_value()->set_receiver_type(rtype); + else if (no->is_function_declaration()) + no->func_declaration_value()->set_receiver_type(rtype); + else + go_unreachable(); + } + } + } + Type::finalize_methods(gogo, this, this->location_, &this->all_methods_); } -- 2.47.2