compiler: Use backend interface for function declarations.

	* go-gcc.cc (Backend::error_function): New function.
	(Backend::function): New function.
	(Backend::make_function): New function.
	(function_to_tree): New function.

From-SVN: r203403

gcc/go/ChangeLog

+2013-10-10  Chris Manghane  <cmang@google.com>
+
+	* go-gcc.cc (Backend::error_function): New function.
+	(Backend::function): New function.
+	(Backend::make_function): New function.
+	(function_to_tree): New function.
+
 2013-10-04  Chris Manghane  <cmang@google.com>
 
 	* go-gcc.cc (Backend::convert_expression): New function.

gcc/go/go-gcc.cc

@@ -334,6 +334,17 @@ class Gcc_backend : public Backend
   Bexpression*
   label_address(Blabel*, Location);
 
+  // Functions.
+
+  Bfunction*
+  error_function()
+  { return this->make_function(error_mark_node); }
+
+  Bfunction*
+  function(Btype* fntype, const std::string& name, const std::string& asm_name,
+           bool is_visible, bool is_declaration, bool is_inlinable,
+           bool disable_split_stack, bool in_unique_section, Location);
+
  private:
   // Make a Bexpression from a tree.
   Bexpression*
@@ -350,6 +361,10 @@ class Gcc_backend : public Backend
   make_type(tree t)
   { return new Btype(t); }
 
+  Bfunction*
+  make_function(tree t)
+  { return new Bfunction(t); }
+
   Btype*
   fill_in_struct(Btype*, const std::vector<Btyped_identifier>&);
 
@@ -1724,6 +1739,56 @@ Gcc_backend::label_address(Blabel* label, Location location)
   return this->make_expression(ret);
 }
 
+// Declare or define a new function.
+
+Bfunction*
+Gcc_backend::function(Btype* fntype, const std::string& name,
+                      const std::string& asm_name, bool is_visible,
+                      bool is_declaration, bool is_inlinable,
+                      bool disable_split_stack, bool in_unique_section,
+                      Location location)
+{
+  tree functype = fntype->get_tree();
+  if (functype != error_mark_node)
+    {
+      gcc_assert(FUNCTION_POINTER_TYPE_P(functype));
+      functype = TREE_TYPE(functype);
+    }
+  tree id = get_identifier_from_string(name);
+  if (functype == error_mark_node || id == error_mark_node)
+    return this->error_function();
+
+  tree decl = build_decl(location.gcc_location(), FUNCTION_DECL, id, functype);
+  if (!asm_name.empty())
+    SET_DECL_ASSEMBLER_NAME(decl, get_identifier_from_string(asm_name));
+  if (is_visible)
+    TREE_PUBLIC(decl) = 1;
+  if (is_declaration)
+    DECL_EXTERNAL(decl) = 1;
+  else
+    {
+      tree restype = TREE_TYPE(functype);
+      tree resdecl =
+          build_decl(location.gcc_location(), RESULT_DECL, NULL_TREE, restype);
+      DECL_ARTIFICIAL(resdecl) = 1;
+      DECL_IGNORED_P(resdecl) = 1;
+      DECL_CONTEXT(resdecl) = decl;
+      DECL_RESULT(decl) = resdecl;
+    }
+  if (!is_inlinable)
+    DECL_UNINLINABLE(decl) = 1;
+  if (disable_split_stack)
+    {
+      tree attr = get_identifier("__no_split_stack__");
+      DECL_ATTRIBUTES(decl) = tree_cons(attr, NULL_TREE, NULL_TREE);
+    }
+  if (in_unique_section)
+    resolve_unique_section(decl, 0, 1);
+
+  go_preserve_from_gc(decl);
+  return new Bfunction(decl);
+}
+
 // The single backend.
 
 static Gcc_backend gcc_backend;
@@ -1799,3 +1864,9 @@ var_to_tree(Bvariable* bv)
 {
   return bv->get_tree();
 }
+
+tree
+function_to_tree(Bfunction* bf)
+{
+  return bf->get_tree();
+}

gcc/go/gofrontend/backend.h

@@ -23,7 +23,7 @@ class Bexpression;
 // The backend representation of a statement.
 class Bstatement;
 
-// The backend representation of a function definition.
+// The backend representation of a function definition or declaration.
 class Bfunction;
 
 // The backend representation of a block.
@@ -498,6 +498,32 @@ class Backend
   // recover.
   virtual Bexpression*
   label_address(Blabel*, Location) = 0;
+
+  // Functions.
+
+  // Create an error function.  This is used for cases which should
+  // not occur in a correct program, in order to keep the compilation
+  // going without crashing.
+  virtual Bfunction*
+  error_function() = 0;
+
+  // Declare or define a function of FNTYPE.
+  // NAME is the Go name of the function. ASM_NAME, if not the empty string, is
+  // the name that should be used in the symbol table; this will be non-empty if
+  // a magic extern comment is used.
+  // IS_VISIBLE is true if this function should be visible outside of the
+  // current compilation unit. IS_DECLARATION is true if this is a function
+  // declaration rather than a definition; the function definition will be in
+  // another compilation unit.
+  // IS_INLINABLE is true if the function can be inlined.
+  // DISABLE_SPLIT_STACK is true if this function may not split the stack; this
+  // is used for the implementation of recover.
+  // IN_UNIQUE_SECTION is true if this function should be put into a unique
+  // location if possible; this is used for field tracking.
+  virtual Bfunction*
+  function(Btype* fntype, const std::string& name, const std::string& asm_name,
+           bool is_visible, bool is_declaration, bool is_inlinable,
+           bool disable_split_stack, bool in_unique_section, Location) = 0;
 };
 
 // The backend interface has to define this function.
@@ -517,5 +543,6 @@ extern tree expr_to_tree(Bexpression*);
 extern tree stat_to_tree(Bstatement*);
 extern tree block_to_tree(Bblock*);
 extern tree var_to_tree(Bvariable*);
+extern tree function_to_tree(Bfunction*);
 
 #endif // !defined(GO_BACKEND_H)

gcc/go/gofrontend/expressions.cc

@@ -1240,15 +1240,11 @@ Func_expression::get_code_pointer(Gogo* gogo, Named_object* no, Location loc)
       return error_mark_node;
     }
 
-  tree id = no->get_id(gogo);
-  if (id == error_mark_node)
-    return error_mark_node;
-
   tree fndecl;
   if (no->is_function())
-    fndecl = no->func_value()->get_or_make_decl(gogo, no, id);
+    fndecl = no->func_value()->get_or_make_decl(gogo, no);
   else if (no->is_function_declaration())
-    fndecl = no->func_declaration_value()->get_or_make_decl(gogo, no, id);
+    fndecl = no->func_declaration_value()->get_or_make_decl(gogo, no);
   else
     go_unreachable();
 
@@ -9825,14 +9821,8 @@ Call_expression::do_get_tree(Translate_context* context)
     }
 
   tree fntype_tree = type_to_tree(fntype->get_backend(gogo));
-  if (fntype_tree == error_mark_node)
-    return error_mark_node;
-  go_assert(POINTER_TYPE_P(fntype_tree));
-  if (TREE_TYPE(fntype_tree) == error_mark_node)
-    return error_mark_node;
-  go_assert(TREE_CODE(TREE_TYPE(fntype_tree)) == RECORD_TYPE);
-  tree fnfield_type = TREE_TYPE(TYPE_FIELDS(TREE_TYPE(fntype_tree)));
-  if (fnfield_type == error_mark_node)
+  tree fnfield_type = type_to_tree(fntype->get_backend_fntype(gogo));
+  if (fntype_tree == error_mark_node || fnfield_type == error_mark_node)
     return error_mark_node;
   go_assert(FUNCTION_POINTER_TYPE_P(fnfield_type));
   tree rettype = TREE_TYPE(TREE_TYPE(fnfield_type));

gcc/go/gofrontend/gogo.cc

@@ -5110,6 +5110,75 @@ Named_object::get_backend_variable(Gogo* gogo, Named_object* function)
     go_unreachable();
 }
 
+
+// Return the external identifier for this object.
+
+std::string
+Named_object::get_id(Gogo* gogo)
+{
+  go_assert(!this->is_variable() && !this->is_result_variable());
+  std::string decl_name;
+  if (this->is_function_declaration()
+      && !this->func_declaration_value()->asm_name().empty())
+    decl_name = this->func_declaration_value()->asm_name();
+  else if (this->is_type()
+	   && Linemap::is_predeclared_location(this->type_value()->location()))
+    {
+      // We don't need the package name for builtin types.
+      decl_name = Gogo::unpack_hidden_name(this->name_);
+    }
+  else
+    {
+      std::string package_name;
+      if (this->package_ == NULL)
+	package_name = gogo->package_name();
+      else
+	package_name = this->package_->package_name();
+
+      // Note that this will be misleading if this is an unexported
+      // method generated for an embedded imported type.  In that case
+      // the unexported method should have the package name of the
+      // package from which it is imported, but we are going to give
+      // it our package name.  Fixing this would require knowing the
+      // package name, but we only know the package path.  It might be
+      // better to use package paths here anyhow.  This doesn't affect
+      // the assembler code, because we always set that name in
+      // Function::get_or_make_decl anyhow.  FIXME.
+
+      decl_name = package_name + '.' + Gogo::unpack_hidden_name(this->name_);
+
+      Function_type* fntype;
+      if (this->is_function())
+	fntype = this->func_value()->type();
+      else if (this->is_function_declaration())
+	fntype = this->func_declaration_value()->type();
+      else
+	fntype = NULL;
+      if (fntype != NULL && fntype->is_method())
+	{
+	  decl_name.push_back('.');
+	  decl_name.append(fntype->receiver()->type()->mangled_name(gogo));
+	}
+    }
+  if (this->is_type())
+    {
+      unsigned int index;
+      const Named_object* in_function = this->type_value()->in_function(&index);
+      if (in_function != NULL)
+	{
+	  decl_name += '$' + Gogo::unpack_hidden_name(in_function->name());
+	  if (index > 0)
+	    {
+	      char buf[30];
+	      snprintf(buf, sizeof buf, "%u", index);
+	      decl_name += '$';
+	      decl_name += buf;
+	    }
+	}
+    }
+  return decl_name;
+}
+
 // Class Bindings.
 
 Bindings::Bindings(Bindings* enclosing)

gcc/go/gofrontend/gogo.h

@@ -48,6 +48,7 @@ class Bstatement;
 class Bblock;
 class Bvariable;
 class Blabel;
+class Bfunction;
 
 // This file declares the basic classes used to hold the internal
 // representation of Go which is built by the parser.
@@ -1091,15 +1092,11 @@ class Function
 
   // Return the function's decl given an identifier.
   tree
-  get_or_make_decl(Gogo*, Named_object*, tree id);
+  get_or_make_decl(Gogo*, Named_object*);
 
   // Return the function's decl after it has been built.
   tree
-  get_decl() const
-  {
-    go_assert(this->fndecl_ != NULL);
-    return this->fndecl_;
-  }
+  get_decl() const;
 
   // Set the function decl to hold a tree of the function code.
   void
@@ -1170,7 +1167,7 @@ class Function
   // The function descriptor, if any.
   Expression* descriptor_;
   // The function decl.
-  tree fndecl_;
+  Bfunction* fndecl_;
   // The defer stack variable.  A pointer to this variable is used to
   // distinguish the defer stack for one function from another.  This
   // is NULL unless we actually need a defer stack.
@@ -1267,7 +1264,7 @@ class Function_declaration
 
   // Return a decl for the function given an identifier.
   tree
-  get_or_make_decl(Gogo*, Named_object*, tree id);
+  get_or_make_decl(Gogo*, Named_object*);
 
   // If there is a descriptor, build it into the backend
   // representation.
@@ -1290,7 +1287,7 @@ class Function_declaration
   // The function descriptor, if any.
   Expression* descriptor_;
   // The function decl if needed.
-  tree fndecl_;
+  Bfunction* fndecl_;
 };
 
 // A variable.
@@ -2181,8 +2178,8 @@ class Named_object
   Bvariable*
   get_backend_variable(Gogo*, Named_object* function);
 
-  // Return a tree for the external identifier for this object.
-  tree
+  // Return the external identifier for this object.
+  std::string
   get_id(Gogo*);
 
   // Return a tree representing this object.

gcc/go/gofrontend/types.cc

@@ -3383,6 +3383,68 @@ Function_type::do_hash_for_method(Gogo* gogo) const
 // Get the backend representation for a function type.
 
 Btype*
+Function_type::get_backend_fntype(Gogo* gogo)
+{
+  if (this->fnbtype_ == NULL)
+    {
+      Backend::Btyped_identifier breceiver;
+      if (this->receiver_ != NULL)
+        {
+          breceiver.name = Gogo::unpack_hidden_name(this->receiver_->name());
+
+          // We always pass the address of the receiver parameter, in
+          // order to make interface calls work with unknown types.
+          Type* rtype = this->receiver_->type();
+          if (rtype->points_to() == NULL)
+            rtype = Type::make_pointer_type(rtype);
+          breceiver.btype = rtype->get_backend(gogo);
+          breceiver.location = this->receiver_->location();
+        }
+
+      std::vector<Backend::Btyped_identifier> bparameters;
+      if (this->parameters_ != NULL)
+        {
+          bparameters.resize(this->parameters_->size());
+          size_t i = 0;
+          for (Typed_identifier_list::const_iterator p =
+                   this->parameters_->begin(); p != this->parameters_->end();
+               ++p, ++i)
+	    {
+              bparameters[i].name = Gogo::unpack_hidden_name(p->name());
+              bparameters[i].btype = p->type()->get_backend(gogo);
+              bparameters[i].location = p->location();
+            }
+          go_assert(i == bparameters.size());
+        }
+
+      std::vector<Backend::Btyped_identifier> bresults;
+      if (this->results_ != NULL)
+        {
+          bresults.resize(this->results_->size());
+          size_t i = 0;
+          for (Typed_identifier_list::const_iterator p =
+                   this->results_->begin(); p != this->results_->end();
+               ++p, ++i)
+	    {
+              bresults[i].name = Gogo::unpack_hidden_name(p->name());
+              bresults[i].btype = p->type()->get_backend(gogo);
+              bresults[i].location = p->location();
+            }
+          go_assert(i == bresults.size());
+        }
+
+      this->fnbtype_ = gogo->backend()->function_type(breceiver, bparameters,
+                                                      bresults,
+                                                      this->location());
+
+    }
+
+  return this->fnbtype_;
+}
+
+// Get the backend representation for a Go function type.
+
+Btype*
 Function_type::do_get_backend(Gogo* gogo)
 {
   // When we do anything with a function value other than call it, it
@@ -3395,57 +3457,9 @@ Function_type::do_get_backend(Gogo* gogo)
     gogo->backend()->placeholder_struct_type("__go_descriptor", loc);
   Btype* ptr_struct_type = gogo->backend()->pointer_type(struct_type);
 
-  Backend::Btyped_identifier breceiver;
-  if (this->receiver_ != NULL)
-    {
-      breceiver.name = Gogo::unpack_hidden_name(this->receiver_->name());
-
-      // We always pass the address of the receiver parameter, in
-      // order to make interface calls work with unknown types.
-      Type* rtype = this->receiver_->type();
-      if (rtype->points_to() == NULL)
-	rtype = Type::make_pointer_type(rtype);
-      breceiver.btype = rtype->get_backend(gogo);
-      breceiver.location = this->receiver_->location();
-    }
-
-  std::vector<Backend::Btyped_identifier> bparameters;
-  if (this->parameters_ != NULL)
-    {
-      bparameters.resize(this->parameters_->size());
-      size_t i = 0;
-      for (Typed_identifier_list::const_iterator p = this->parameters_->begin();
-	   p != this->parameters_->end();
-	   ++p, ++i)
-	{
-	  bparameters[i].name = Gogo::unpack_hidden_name(p->name());
-	  bparameters[i].btype = p->type()->get_backend(gogo);
-	  bparameters[i].location = p->location();
-	}
-      go_assert(i == bparameters.size());
-    }
-
-  std::vector<Backend::Btyped_identifier> bresults;
-  if (this->results_ != NULL)
-    {
-      bresults.resize(this->results_->size());
-      size_t i = 0;
-      for (Typed_identifier_list::const_iterator p = this->results_->begin();
-	   p != this->results_->end();
-	   ++p, ++i)
-	{
-	  bresults[i].name = Gogo::unpack_hidden_name(p->name());
-	  bresults[i].btype = p->type()->get_backend(gogo);
-	  bresults[i].location = p->location();
-	}
-      go_assert(i == bresults.size());
-    }
-
-  Btype* fntype = gogo->backend()->function_type(breceiver, bparameters,
-						 bresults, loc);
   std::vector<Backend::Btyped_identifier> fields(1);
   fields[0].name = "code";
-  fields[0].btype = fntype;
+  fields[0].btype = this->get_backend_fntype(gogo);
   fields[0].location = loc;
   if (!gogo->backend()->set_placeholder_struct_type(struct_type, fields))
     return gogo->backend()->error_type();

gcc/go/gofrontend/types.h

@@ -1717,7 +1717,8 @@ class Function_type : public Type
 		Typed_identifier_list* results, Location location)
     : Type(TYPE_FUNCTION),
       receiver_(receiver), parameters_(parameters), results_(results),
-      location_(location), is_varargs_(false), is_builtin_(false)
+      location_(location), is_varargs_(false), is_builtin_(false),
+      fnbtype_(NULL)
   { }
 
   // Get the receiver.
@@ -1798,6 +1799,11 @@ class Function_type : public Type
   static Type*
   make_function_type_descriptor_type();
 
+  // Return the backend representation of this function type. This is used
+  // as the real type of a backend function declaration or defintion.
+  Btype*
+  get_backend_fntype(Gogo*);
+
  protected:
   int
   do_traverse(Traverse*);
@@ -1851,6 +1857,9 @@ class Function_type : public Type
   // Whether this is a special builtin function which can not simply
   // be called.  This is used for len, cap, etc.
   bool is_builtin_;
+  // The backend representation of this type for backend function
+  // declarations and definitions.
+  Btype* fnbtype_;
 };
 
 // The type of a pointer.