target-def.h (TARGET_CXX_CDTOR_RETURNS_THIS): Define.

gcc/
	* target-def.h (TARGET_CXX_CDTOR_RETURNS_THIS): Define.
	(TARGET_CXX): Use it.
	* target.h (struct gcc_target): Add cdtor_returns_this.
	* config/arm/arm.c (arm_cxx_cdtor_returns_this): New function.
	(TARGET_CXX_CDTOR_RETURNS_THIS): Define.
	* doc/tm.texi: Document TARGET_CXX_CDTOR_RETURNS_THIS.
gcc/cp/
	* Make-lang.in (cp/semantics.o, cp/optimize.o): Depend on TARGET_H.
	* cp-tree.h (struct language_function): Rename x_dtor_label to
	x_cdtor_label.
	(dtor_label): Rename ...
	(cdtor_label): ... to this.
	* decl.c (begin_constructor_body): Remove.
	(check_special_function_return_type): Maybe change the return type.
	(grokdeclarator): Pass the class type.
	(start_preparsed_function): Constructors may need a return label.
	(finish_constructor_body, finish_destructor_body): Set the return
	value.
	(begin_function_body): Don't call begin_constructor_body.
	(finish_function): Don't warn for constructors or destructors.
	(implicitly_declare_fn): Maybe change the return type.
	* optimize.c: Include target.h.
	(maybe_clone_body): Remap the function result.
	* semantics.c: Include target.h.
	(finish_return_stmt): Maybe jump to return label for constructors.

From-SVN: r85561

gcc/ChangeLog

+2004-08-04  Paul Brook  <paul@codesourcery.com>
+
+	* target-def.h (TARGET_CXX_CDTOR_RETURNS_THIS): Define.
+	(TARGET_CXX): Use it.
+	* target.h (struct gcc_target): Add cdtor_returns_this.
+	* config/arm/arm.c (arm_cxx_cdtor_returns_this): New function.
+	(TARGET_CXX_CDTOR_RETURNS_THIS): Define.
+	* doc/tm.texi: Document TARGET_CXX_CDTOR_RETURNS_THIS.
+
 2004-08-03  Nathan Sidwell  <nathan@codesourcery.com>
 
 	* c-lex.c (narrowest_unsigned_type, narrowest_signed_type): Take

gcc/config/arm/arm.c

@@ -168,6 +168,7 @@ static tree arm_cxx_guard_type (void);
 static bool arm_cxx_guard_mask_bit (void);
 static tree arm_get_cookie_size (tree);
 static bool arm_cookie_has_size (void);
+static bool arm_cxx_cdtor_returns_this (void);
 
 
 /* Initialize the GCC target structure.  */
@@ -282,6 +283,9 @@ static bool arm_cookie_has_size (void);
 #undef TARGET_CXX_COOKIE_HAS_SIZE
 #define TARGET_CXX_COOKIE_HAS_SIZE arm_cookie_has_size
 
+#undef TARGET_CXX_CDTOR_RETURNS_THIS
+#define TARGET_CXX_CDTOR_RETURNS_THIS arm_cxx_cdtor_returns_this
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 /* Obstack for minipool constant handling.  */
@@ -14578,3 +14582,13 @@ arm_cookie_has_size (void)
 {
   return TARGET_AAPCS_BASED;
 }
+
+
+/* The EABI says constructors and destructors should return a pointer to
+   the object constructed/destroyed.  */
+
+static bool
+arm_cxx_cdtor_returns_this (void)
+{
+  return TARGET_AAPCS_BASED;
+}

gcc/cp/ChangeLog

+2004-08-04  Paul Brook  <paul@codesourcery.com>
+
+	* Make-lang.in (cp/semantics.o, cp/optimize.o): Depend on TARGET_H.
+	* cp-tree.h (struct language_function): Rename x_dtor_label to
+	x_cdtor_label.
+	(dtor_label): Rename ...
+	(cdtor_label): ... to this.
+	* decl.c (begin_constructor_body): Remove.
+	(check_special_function_return_type): Maybe change the return type.
+	(grokdeclarator): Pass the class type.
+	(start_preparsed_function): Constructors may need a return label.
+	(finish_constructor_body, finish_destructor_body): Set the return
+	value.
+	(begin_function_body): Don't call begin_constructor_body.
+	(finish_function): Don't warn for constructors or destructors.
+	(implicitly_declare_fn): Maybe change the return type.
+	* optimize.c: Include target.h.
+	(maybe_clone_body): Remap the function result.
+	* semantics.c: Include target.h.
+	(finish_return_stmt): Maybe jump to return label for constructors.
+
 2004-08-03  Mark Mitchell  <mark@codesourcery.com>
 
 	* class.c (build_vtable): Do not set DECL_VISIBILITY here.

gcc/cp/Make-lang.in

@@ -260,10 +260,10 @@ cp/repo.o: cp/repo.c $(CXX_TREE_H) $(TM_H) toplev.h diagnostic.h \
   gt-cp-repo.h
 cp/semantics.o: cp/semantics.c $(CXX_TREE_H) $(TM_H) except.h toplev.h \
   flags.h debug.h output.h $(RTL_H) $(TIMEVAR_H) $(EXPR_H) \
-  tree-inline.h cgraph.h
+  tree-inline.h cgraph.h $(TAREGT_H)
 cp/dump.o: cp/dump.c $(CXX_TREE_H) $(TM_H) tree-dump.h
 cp/optimize.o: cp/optimize.c $(CXX_TREE_H) $(TM_H) rtl.h integrate.h insn-config.h \
-  input.h $(PARAMS_H) debug.h tree-inline.h tree-gimple.h
+  input.h $(PARAMS_H) debug.h tree-inline.h tree-gimple.h $(TARGET_H)
 cp/mangle.o: cp/mangle.c $(CXX_TREE_H) $(TM_H) toplev.h real.h gt-cp-mangle.h \
   $(TARGET_H) $(TM_P_H)
 

gcc/cp/cp-tree.h

@@ -708,7 +708,7 @@ struct language_function GTY(())
 {
   struct c_language_function base;
 
-  tree x_dtor_label;
+  tree x_cdtor_label;
   tree x_current_class_ptr;
   tree x_current_class_ref;
   tree x_eh_spec_block;
@@ -735,10 +735,12 @@ struct language_function GTY(())
 
 #define cp_function_chain (cfun->language)
 
-/* In a destructor, the point at which all derived class destroying
-   has been done, just before any base class destroying will be done.  */
+/* In a constructor destructor, the point at which all derived class
+   destroying/contruction has been has been done. Ie. just before a
+   constuctor returns, or before any base class destroying will be done
+   in a destructor.  */
 
-#define dtor_label cp_function_chain->x_dtor_label
+#define cdtor_label cp_function_chain->x_cdtor_label
 
 /* When we're processing a member function, current_class_ptr is the
    PARM_DECL for the `this' pointer.  The current_class_ref is an

gcc/cp/decl.c

@@ -100,7 +100,6 @@ static tree check_initializer (tree, tree, int, tree *);
 static void make_rtl_for_nonlocal_decl (tree, tree, const char *);
 static void save_function_data (tree);
 static void check_function_type (tree, tree);
-static void begin_constructor_body (void);
 static void finish_constructor_body (void);
 static void begin_destructor_body (void);
 static void finish_destructor_body (void);
@@ -6182,7 +6181,8 @@ create_array_type_for_decl (tree name, tree type, tree size)
 /* Check that it's OK to declare a function with the indicated TYPE.
    SFK indicates the kind of special function (if any) that this
    function is.  OPTYPE is the type given in a conversion operator
-   declaration.  Returns the actual return type of the function; that
+   declaration, or the class type for a constructor/destructor.
+   Returns the actual return type of the function; that
    may be different than TYPE if an error occurs, or for certain
    special functions.  */
 
@@ -6197,13 +6197,23 @@ check_special_function_return_type (special_function_kind sfk,
       if (type)
 	error ("return type specification for constructor invalid");
 
-      type = void_type_node;
+      if (targetm.cxx.cdtor_returns_this () && !TYPE_FOR_JAVA (optype))
+	type = build_pointer_type (optype);
+      else
+	type = void_type_node;
       break;
 
     case sfk_destructor:
       if (type)
 	error ("return type specification for destructor invalid");
-      type = void_type_node;
+      /* We can't use the proper return type here because we run into
+	 problems with abiguous bases and covariant returns.
+	 Java classes are left unchanged because (void *) isn't a valid
+	 Java type, and we don't want to change the Java ABI.  */
+      if (targetm.cxx.cdtor_returns_this () && !TYPE_FOR_JAVA (optype))
+	type = build_pointer_type (void_type_node);
+      else
+	type = void_type_node;
       break;
 
     case sfk_conversion:
@@ -6589,6 +6599,9 @@ grokdeclarator (const cp_declarator *declarator,
   typedef_type = type;
 
 
+  if (sfk != sfk_conversion)
+    ctor_return_type = ctype;
+
   if (sfk != sfk_none)
     type = check_special_function_return_type (sfk, type,
 					       ctor_return_type);
@@ -9879,10 +9892,12 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
 
   ++function_depth;
 
-  if (DECL_DESTRUCTOR_P (decl1))
+  if (DECL_DESTRUCTOR_P (decl1)
+      || (DECL_CONSTRUCTOR_P (decl1)
+	  && targetm.cxx.cdtor_returns_this ()))
     {
-      dtor_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
-      DECL_CONTEXT (dtor_label) = current_function_decl;
+      cdtor_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
+      DECL_CONTEXT (cdtor_label) = current_function_decl;
     }
 
   start_fname_decls ();
@@ -10050,22 +10065,27 @@ save_function_data (tree decl)
   f->x_local_names = NULL;
 }
 
-/* Add a note to mark the beginning of the main body of the constructor.
-   This is used to set up the data structures for the cleanup regions for
-   fully-constructed bases and members.  */
 
-static void
-begin_constructor_body (void)
-{
-}
-
-/* Add a note to mark the end of the main body of the constructor.  This is
-   used to end the cleanup regions for fully-constructed bases and
-   members.  */
+/* Set the return value of the constructor (if present).  */
 
 static void
 finish_constructor_body (void)
 {
+  tree val;
+  tree exprstmt;
+
+  if (targetm.cxx.cdtor_returns_this ())
+    {
+      /* Any return from a constructor will end up here.  */
+      add_stmt (build_stmt (LABEL_EXPR, cdtor_label));
+
+      val = DECL_ARGUMENTS (current_function_decl);
+      val = build (MODIFY_EXPR, TREE_TYPE (val),
+		   DECL_RESULT (current_function_decl), val);
+      /* Return the address of the object.  */
+      exprstmt = build_stmt (RETURN_EXPR, val);
+      add_stmt (exprstmt);
+    }
 }
 
 /* Do all the processing for the beginning of a destructor; set up the
@@ -10125,7 +10145,7 @@ finish_destructor_body (void)
 
   /* Any return from a destructor will end up here; that way all base
      and member cleanups will be run when the function returns.  */
-  add_stmt (build_stmt (LABEL_EXPR, dtor_label));
+  add_stmt (build_stmt (LABEL_EXPR, cdtor_label));
 
   /* In a virtual destructor, we must call delete.  */
   if (DECL_VIRTUAL_P (current_function_decl))
@@ -10152,6 +10172,18 @@ finish_destructor_body (void)
       finish_then_clause (if_stmt);
       finish_if_stmt (if_stmt);
     }
+
+  if (targetm.cxx.cdtor_returns_this ())
+    {
+      tree val;
+
+      val = DECL_ARGUMENTS (current_function_decl);
+      val = build (MODIFY_EXPR, TREE_TYPE (val),
+		   DECL_RESULT (current_function_decl), val);
+      /* Return the address of the object.  */
+      exprstmt = build_stmt (RETURN_EXPR, val);
+      add_stmt (exprstmt);
+    }
 }
 
 /* Do the necessary processing for the beginning of a function body, which
@@ -10177,8 +10209,6 @@ begin_function_body (void)
 
   if (processing_template_decl)
     /* Do nothing now.  */;
-  else if (DECL_CONSTRUCTOR_P (current_function_decl))
-    begin_constructor_body ();
   else if (DECL_DESTRUCTOR_P (current_function_decl))
     begin_destructor_body ();
 
@@ -10363,7 +10393,10 @@ finish_function (int flags)
       && !DECL_NAME (DECL_RESULT (fndecl))
       /* Normally, with -Wreturn-type, flow will complain.  Unless we're an
 	 inline function, as we might never be compiled separately.  */
-      && (DECL_INLINE (fndecl) || processing_template_decl))
+      && (DECL_INLINE (fndecl) || processing_template_decl)
+      /* Structor return values (if any) are set by the compiler.  */
+      && !DECL_CONSTRUCTOR_P (fndecl)
+      && !DECL_DESTRUCTOR_P (fndecl))
     warning ("no return statement in function returning non-void");
 
   /* Store the end of the function, so that we get good line number

gcc/cp/method.c

@@ -929,7 +929,7 @@ implicitly_declare_fn (special_function_kind kind, tree type, bool const_p)
 {
   tree fn;
   tree parameter_types = void_list_node;
-  tree return_type = void_type_node;
+  tree return_type;
   tree fn_type;
   tree raises = empty_except_spec;
   tree rhs_parm_type = NULL_TREE;
@@ -937,6 +937,17 @@ implicitly_declare_fn (special_function_kind kind, tree type, bool const_p)
 
   type = TYPE_MAIN_VARIANT (type);
 
+  if (targetm.cxx.cdtor_returns_this () && !TYPE_FOR_JAVA (type))
+    {
+      if (kind == sfk_destructor)
+	/* See comment in check_special_function_return_type.  */
+	return_type = build_pointer_type (void_type_node);
+      else
+	return_type = build_pointer_type (type);
+    }
+  else
+    return_type = void_type_node;
+
   switch (kind)
     {
     case sfk_destructor:

gcc/cp/optimize.c

@@ -34,6 +34,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 #include "varray.h"
 #include "params.h"
 #include "hashtab.h"
+#include "target.h"
 #include "debug.h"
 #include "tree-inline.h"
 #include "flags.h"
@@ -184,6 +185,13 @@ maybe_clone_body (tree fn)
 	    }
 	}
 
+      if (targetm.cxx.cdtor_returns_this ())
+	{
+	  parm = DECL_RESULT (fn);
+	  clone_parm = DECL_RESULT (clone);
+	  splay_tree_insert (decl_map, (splay_tree_key) parm,
+			     (splay_tree_value) clone_parm);
+	}
       /* Clone the body.  */
       clone_body (clone, fn, decl_map);
 

gcc/cp/semantics.c

@@ -45,6 +45,7 @@
 #include "cgraph.h"
 #include "tree-iterator.h"
 #include "vec.h"
+#include "target.h"
 
 /* There routines provide a modular interface to perform many parsing
    operations.  They may therefore be used during actual parsing, or
@@ -703,13 +704,15 @@ finish_return_stmt (tree expr)
   expr = check_return_expr (expr);
   if (!processing_template_decl)
     {
-      if (DECL_DESTRUCTOR_P (current_function_decl))
+      if (DECL_DESTRUCTOR_P (current_function_decl)
+	  || (DECL_CONSTRUCTOR_P (current_function_decl) 
+	      && targetm.cxx.cdtor_returns_this ()))
 	{
 	  /* Similarly, all destructors must run destructors for
 	     base-classes before returning.  So, all returns in a
 	     destructor get sent to the DTOR_LABEL; finish_function emits
 	     code to return a value there.  */
-	  return finish_goto_stmt (dtor_label);
+	  return finish_goto_stmt (cdtor_label);
 	}
     }
 

gcc/doc/tm.texi

@@ -8469,6 +8469,12 @@ modified value and perform any other actions necessary to support the
 backend's targeted operating system.
 @end deftypefn
 
+@deftypefn {Target Hook} bool TARGET_CXX_CDTOR_RETURNS_THIS (void)
+This hook should return @code{true} if constructors and destructors return
+the address of the object created/destroyed.  The default is to return
+@code{false}.
+@end deftypefn
+
 @node Misc
 @section Miscellaneous Parameters
 @cindex parameters, miscellaneous

gcc/target-def.h

@@ -412,13 +412,18 @@ Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 #define TARGET_CXX_IMPORT_EXPORT_CLASS NULL
 #endif
 
+#ifndef TARGET_CXX_CDTOR_RETURNS_THIS
+#define TARGET_CXX_CDTOR_RETURNS_THIS hook_bool_void_false
+#endif
+
 #define TARGET_CXX		\
   {				\
     TARGET_CXX_GUARD_TYPE,	\
     TARGET_CXX_GUARD_MASK_BIT,	\
     TARGET_CXX_GET_COOKIE_SIZE,	\
     TARGET_CXX_COOKIE_HAS_SIZE,	\
-    TARGET_CXX_IMPORT_EXPORT_CLASS	\
+    TARGET_CXX_IMPORT_EXPORT_CLASS,	\
+    TARGET_CXX_CDTOR_RETURNS_THIS	\
   }
 
 /* The whole shebang.  */

gcc/target.h

@@ -492,6 +492,8 @@ struct gcc_target
     /* Allows backends to perform additional processing when
        deciding if a class should be exported or imported.  */
     int (*import_export_class) (tree, int);
+    /* Returns true if constructors and destructors return "this".  */
+    bool (*cdtor_returns_this) (void);
   } cxx;
 
   /* Leave the boolean fields at the end.  */