compiler: track //go:nointerface in export data

The magic //go:nointerface comment, used for field tracking, was only
    implemented for conversions to interface types in the same package.
    Record it in the export data, so that it works as expected for types
    imported from a different package.
    
    Reviewed-on: https://go-review.googlesource.com/93075

From-SVN: r257540

gcc/go/gofrontend/MERGE

@@ -1,4 +1,4 @@
-7e94bac5676afc8188677c98ecb263c78c1a7f8d
+89105404f94005ffa8e2b08df78015dc9ac91362
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/gogo.cc

@@ -5189,17 +5189,24 @@ Function::defer_stack(Location location)
 void
 Function::export_func(Export* exp, const std::string& name) const
 {
-  Function::export_func_with_type(exp, name, this->type_);
+  Function::export_func_with_type(exp, name, this->type_,
+				  this->is_method() && this->nointerface());
 }
 
 // Export a function with a type.
 
 void
 Function::export_func_with_type(Export* exp, const std::string& name,
-				const Function_type* fntype)
+				const Function_type* fntype, bool nointerface)
 {
   exp->write_c_string("func ");
 
+  if (nointerface)
+    {
+      go_assert(fntype->is_method());
+      exp->write_c_string("/*nointerface*/ ");
+    }
+
   if (fntype->is_method())
     {
       exp->write_c_string("(");
@@ -5280,10 +5287,21 @@ Function::import_func(Import* imp, std::string* pname,
 		      Typed_identifier** preceiver,
 		      Typed_identifier_list** pparameters,
 		      Typed_identifier_list** presults,
-		      bool* is_varargs)
+		      bool* is_varargs,
+		      bool* nointerface)
 {
   imp->require_c_string("func ");
 
+  *nointerface = false;
+  if (imp->match_c_string("/*"))
+    {
+      imp->require_c_string("/*nointerface*/ ");
+      *nointerface = true;
+
+      // Only a method can be nointerface.
+      go_assert(imp->peek_char() == '(');
+    }
+
   *preceiver = NULL;
   if (imp->peek_char() == '(')
     {
@@ -6213,6 +6231,32 @@ Bindings_snapshot::check_goto_defs(Location loc, const Block* block,
 
 // Class Function_declaration.
 
+// Whether this declares a method.
+
+bool
+Function_declaration::is_method() const
+{
+  return this->fntype_->is_method();
+}
+
+// Whether this method should not be included in the type descriptor.
+
+bool
+Function_declaration::nointerface() const
+{
+  go_assert(this->is_method());
+  return (this->pragmas_ & GOPRAGMA_NOINTERFACE) != 0;
+}
+
+// Record that this method should not be included in the type
+// descriptor.
+
+void
+Function_declaration::set_nointerface()
+{
+  this->pragmas_ |= GOPRAGMA_NOINTERFACE;
+}
+
 // Return the function descriptor.
 
 Expression*

gcc/go/gofrontend/gogo.h

@@ -1476,13 +1476,14 @@ class Function
   // Export a function with a type.
   static void
   export_func_with_type(Export*, const std::string& name,
-			const Function_type*);
+			const Function_type*, bool nointerface);
 
   // Import a function.
   static void
   import_func(Import*, std::string* pname, Typed_identifier** receiver,
 	      Typed_identifier_list** pparameters,
-	      Typed_identifier_list** presults, bool* is_varargs);
+	      Typed_identifier_list** presults, bool* is_varargs,
+	      bool* nointerface);
 
  private:
   // Type for mapping from label names to Label objects.
@@ -1607,6 +1608,10 @@ class Function_declaration
   location() const
   { return this->location_; }
 
+  // Return whether this function declaration is a method.
+  bool
+  is_method() const;
+
   const std::string&
   asm_name() const
   { return this->asm_name_; }
@@ -1628,6 +1633,16 @@ class Function_declaration
     this->pragmas_ = pragmas;
   }
 
+  // Whether this method should not be included in the type
+  // descriptor.
+  bool
+  nointerface() const;
+
+  // Record that this method should not be included in the type
+  // descriptor.
+  void
+  set_nointerface();
+
   // Return an expression for the function descriptor, given the named
   // object for this function.  This may only be called for functions
   // without a closure.  This will be an immutable struct with one
@@ -1652,7 +1667,10 @@ class Function_declaration
   // Export a function declaration.
   void
   export_func(Export* exp, const std::string& name) const
-  { Function::export_func_with_type(exp, name, this->fntype_); }
+  {
+    Function::export_func_with_type(exp, name, this->fntype_,
+				    this->is_method() && this->nointerface());
+  }
 
   // Check that the types used in this declaration's signature are defined.
   void

gcc/go/gofrontend/import.cc

@@ -607,8 +607,9 @@ Import::import_func(Package* package)
   Typed_identifier_list* parameters;
   Typed_identifier_list* results;
   bool is_varargs;
+  bool nointerface;
   Function::import_func(this, &name, &receiver,
-			&parameters, &results, &is_varargs);
+			&parameters, &results, &is_varargs, &nointerface);
   Function_type *fntype = Type::make_function_type(receiver, parameters,
 						   results, this->location_);
   if (is_varargs)
@@ -648,6 +649,10 @@ Import::import_func(Package* package)
       if (this->add_to_globals_)
 	this->gogo_->add_dot_import_object(no);
     }
+
+  if (nointerface)
+    no->func_declaration_value()->set_nointerface();
+
   return no;
 }
 

gcc/go/gofrontend/types.cc

@@ -9742,7 +9742,12 @@ bool
 Named_method::do_nointerface() const
 {
   Named_object* no = this->named_object_;
-  return no->is_function() && no->func_value()->nointerface();
+  if (no->is_function())
+    return no->func_value()->nointerface();
+  else if (no->is_function_declaration())
+    return no->func_declaration_value()->nointerface();
+  else
+    go_unreachable();
 }
 
 // Class Interface_method.