compiler: change Expression export to use Export_function_body

    
    In preparation for writing expressions to inline function bodies,
    change the existing expression export code to use Export_function_body
    rather than Export.  Adjust existing expression exporters accordingly.
    
    This is a refactoring that doesn't affect compiler output.
    
    Reviewed-on: https://go-review.googlesource.com/c/150063

From-SVN: r266523

gcc/go/gofrontend/MERGE

-f551ab95f46c3d7bb7c032711e10b03bfa995ee2
+db5240278b3b62a919dd88f857e718a66be50346
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/export.cc

@@ -936,21 +936,41 @@ Export::write_unsigned(unsigned value)
   this->write_c_string(buf);
 }
 
-// Export a type.
+// Return the index of a type.
 
-void
-Export::write_type(const Type* type)
+int
+Export::type_index(const Type* type)
 {
   type = type->forwarded();
   Type_refs::const_iterator p = type_refs.find(type);
   go_assert(p != type_refs.end());
   int index = p->second;
   go_assert(index != 0);
+  return index;
+}
+
+// Export a type.
+
+void
+Export::write_type(const Type* type)
+{
+  int index = this->type_index(type);
   char buf[30];
   snprintf(buf, sizeof buf, "<type %d>", index);
   this->write_c_string(buf);
 }
 
+// Export a type to a function body.
+
+void
+Export::write_type_to(const Type* type, Export_function_body* efb)
+{
+  int index = this->type_index(type);
+  char buf[30];
+  snprintf(buf, sizeof buf, "<type %d>", index);
+  efb->write_c_string(buf);
+}
+
 // Export escape note.
 
 void

gcc/go/gofrontend/export.h

@@ -12,6 +12,7 @@
 class Go_sha1_helper;
 class Gogo;
 class Named_object;
+class Export_function_body;
 class Import_init;
 class Named_object;
 class Bindings;
@@ -183,6 +184,10 @@ class Export : public String_dump
   void
   write_type(const Type*);
 
+  // Write a type to an exported function body.
+  void
+  write_type_to(const Type*, Export_function_body*);
+
   // Write the escape note to the export stream.  If NOTE is NULL, write
   // nothing.
   void
@@ -241,6 +246,10 @@ class Export : public String_dump
   void
   register_builtin_type(Gogo*, const char* name, Builtin_code);
 
+  // Return the index of a type in the export data.
+  int
+  type_index(const Type*);
+
   // The stream to which we are writing data.
   Stream* stream_;
   // Index number of next type.
@@ -290,11 +299,11 @@ class Stream_to_string : public Export::Stream
 // to Statements and Expressions.  It builds up the export data for
 // the function.
 
-class Export_function_body
+class Export_function_body : public String_dump
 {
  public:
-  Export_function_body(int indent)
-    : indent_(indent)
+  Export_function_body(Export* exp, int indent)
+    : exp_(exp), indent_(indent)
   { }
 
   // Write a character to the body.
@@ -312,6 +321,11 @@ class Export_function_body
   write_string(const std::string& str)
   { this->body_.append(str); }
 
+  // Write a type reference to the body.
+  void
+  write_type(const Type* type)
+  { this->exp_->write_type_to(type, this); }
+
   // Append as many spaces as the current indentation level.
   void
   indent()
@@ -336,6 +350,8 @@ class Export_function_body
   { return this->body_; }
 
  private:
+  // The overall export data.
+  Export* exp_;
   // The body we are building.
   std::string body_;
   // Current indentation level: the number of spaces before each statement.

gcc/go/gofrontend/expressions.h

@@ -65,7 +65,7 @@ class Conditional_expression;
 class Compound_expression;
 class Numeric_constant;
 class Named_object;
-class Export;
+class Export_function_body;
 class Import;
 class Temporary_statement;
 class Label;
@@ -1009,12 +1009,10 @@ class Expression
   backend_numeric_constant_expression(Translate_context*,
                                       Numeric_constant* val);
 
-  // Export the expression.  This is only used for constants.  It will
-  // be used for things like values of named constants and sizes of
-  // arrays.
+  // Export the expression.
   void
-  export_expression(Export* exp) const
-  { this->do_export(exp); }
+  export_expression(Export_function_body* efb) const
+  { this->do_export(efb); }
 
   // Import an expression.
   static Expression*
@@ -1130,7 +1128,7 @@ class Expression
 
   // Child class implements export.
   virtual void
-  do_export(Export*) const;
+  do_export(Export_function_body*) const;
 
   // For children to call to give an error for an unused value.
   void
@@ -1603,7 +1601,7 @@ class String_expression : public Expression
   export_string(String_dump* exp, const String_expression* str);
 
   void
-  do_export(Export*) const;
+  do_export(Export_function_body*) const;
 
   void
   do_dump_expression(Ast_dump_context*) const;
@@ -1687,7 +1685,7 @@ class Type_conversion_expression : public Expression
   do_get_backend(Translate_context* context);
 
   void
-  do_export(Export*) const;
+  do_export(Export_function_body*) const;
 
   void
   do_dump_expression(Ast_dump_context*) const;
@@ -1878,7 +1876,7 @@ class Unary_expression : public Expression
   do_get_backend(Translate_context*);
 
   void
-  do_export(Export*) const;
+  do_export(Export_function_body*) const;
 
   void
   do_dump_expression(Ast_dump_context*) const;
@@ -2023,7 +2021,7 @@ class Binary_expression : public Expression
   do_get_backend(Translate_context*);
 
   void
-  do_export(Export*) const;
+  do_export(Export_function_body*) const;
 
   void
   do_dump_expression(Ast_dump_context*) const;
@@ -2130,7 +2128,7 @@ class String_concat_expression : public Expression
   { go_unreachable(); }
 
   void
-  do_export(Export*) const
+  do_export(Export_function_body*) const
   { go_unreachable(); }
 
   void
@@ -2456,7 +2454,7 @@ class Builtin_call_expression : public Call_expression
   do_get_backend(Translate_context*);
 
   void
-  do_export(Export*) const;
+  do_export(Export_function_body*) const;
 
   virtual bool
   do_is_recover_call() const;
@@ -3551,7 +3549,7 @@ class Struct_construction_expression : public Expression,
   do_get_backend(Translate_context*);
 
   void
-  do_export(Export*) const;
+  do_export(Export_function_body*) const;
 
   void
   do_dump_expression(Ast_dump_context*) const;
@@ -3606,7 +3604,7 @@ protected:
   do_check_types(Gogo*);
 
   void
-  do_export(Export*) const;
+  do_export(Export_function_body*) const;
 
   // The indexes.
   const std::vector<unsigned long>*
@@ -3744,7 +3742,7 @@ class Map_construction_expression : public Expression
   do_get_backend(Translate_context*);
 
   void
-  do_export(Export*) const;
+  do_export(Export_function_body*) const;
 
   void
   do_dump_expression(Ast_dump_context*) const;
@@ -3859,7 +3857,7 @@ class Heap_expression : public Expression
   // We only export global objects, and the parser does not generate
   // this in global scope.
   void
-  do_export(Export*) const
+  do_export(Export_function_body*) const
   { go_unreachable(); }
 
   void

gcc/go/gofrontend/gogo.cc

@@ -5572,7 +5572,7 @@ Function::export_func_with_type(Export* exp, const std::string& name,
       if (fntype->is_method())
 	indent++;
 
-      Export_function_body efb(indent);
+      Export_function_body efb(exp, indent);
 
       efb.indent();
       efb.write_c_string("// ");
@@ -7606,7 +7606,11 @@ Named_constant::export_const(Export* exp, const std::string& name) const
       exp->write_c_string(" ");
     }
   exp->write_c_string("= ");
-  this->expr()->export_expression(exp);
+
+  Export_function_body efb(exp, 0);
+  this->expr()->export_expression(&efb);
+  exp->write_string(efb.body());
+
   exp->write_c_string("\n");
 }
 

gcc/go/gofrontend/types.cc

@@ -6566,7 +6566,11 @@ Struct_type::do_export(Export* exp) const
 	  exp->write_c_string(" ");
 	  Expression* expr =
             Expression::make_string(p->tag(), Linemap::predeclared_location());
-	  expr->export_expression(exp);
+
+	  Export_function_body efb(exp, 0);
+	  expr->export_expression(&efb);
+	  exp->write_string(efb.body());
+
 	  delete expr;
 	}
 
@@ -7545,7 +7549,11 @@ Array_type::do_export(Export* exp) const
 {
   exp->write_c_string("[");
   if (this->length_ != NULL)
-    this->length_->export_expression(exp);
+    {
+      Export_function_body efb(exp, 0);
+      this->length_->export_expression(&efb);
+      exp->write_string(efb.body());
+    }
   exp->write_c_string("] ");
   exp->write_type(this->element_type_);
 }