700-debian_cp-pass-by-reference.patch

這是一個實時嵌入式作業系統 實作了MCS51 ARM等MCU

This patch needs to be submitted for the FSF.  Also, there may be testcases
already in the GDB testsuite (currently disabled) that it would probably fix.

Index: gdb-6.3/gdb/infcall.c
===================================================================
--- gdb-6.3.orig/gdb/infcall.c	2004-10-08 04:15:56.000000000 -0400
+++ gdb-6.3/gdb/infcall.c	2004-11-10 12:30:07.000000000 -0500
@@ -36,6 +36,7 @@
 #include "gdb_string.h"
 #include "infcall.h"
 #include "dummy-frame.h"
+#include "cp-abi.h"
 
 /* NOTE: cagney/2003-04-16: What's the future of this code?
 
@@ -297,8 +298,8 @@ call_function_by_hand (struct value *fun
 {
   CORE_ADDR sp;
   CORE_ADDR dummy_addr;
-  struct type *value_type;
-  unsigned char struct_return;
+  struct type *value_type, *target_value_type;
+  unsigned char struct_return = 0, cp_struct_return = 0;
   CORE_ADDR struct_addr = 0;
   struct regcache *retbuf;
   struct cleanup *retbuf_cleanup;
@@ -312,6 +313,7 @@ call_function_by_hand (struct value *fun
   struct regcache *caller_regcache;
   struct cleanup *caller_regcache_cleanup;
   struct frame_id dummy_id;
+  struct cleanup *args_cleanup;
 
   if (!target_has_execution)
     noprocess ();
@@ -410,10 +412,31 @@ call_function_by_hand (struct value *fun
     using_gcc = (b == NULL ? 2 : BLOCK_GCC_COMPILED (b));
   }
 
-  /* Are we returning a value using a structure return or a normal
-     value return? */
+  /* Are we returning a value using a structure return (passing a
+     hidden argument pointing to storage) or a normal value return?
+     There are two cases: C++ ABI mandated structure return and
+     target ABI structure return.  The variable STRUCT_RETURN only
+     describes the latter.  The C++ version is handled by passing
+     the return location as the first parameter to the function,
+     even preceding "this".  This is different from the target
+     ABI version, which is target-specific; for instance, on ia64
+     the first argument is passed in out0 but the hidden structure
+     return pointer would normally be passed in r8.  */
 
-  struct_return = using_struct_return (value_type, using_gcc);
+  if (current_language->la_language == language_cplus
+      && cp_pass_by_reference (value_type))
+    {
+      cp_struct_return = 1;
+
+      /* Tell the target specific argument pushing routine not to
+	 expect a value.  */
+      target_value_type = builtin_type_void;
+    }
+  else
+    {
+      struct_return = using_struct_return (value_type, using_gcc);
+      target_value_type = value_type;
+    }
 
   /* Determine the location of the breakpoint (and possibly other
      stuff) that the called function will return to.  The SPARC, for a
@@ -432,7 +455,7 @@ call_function_by_hand (struct value *fun
       if (INNER_THAN (1, 2))
 	{
 	  sp = push_dummy_code (current_gdbarch, sp, funaddr,
-				using_gcc, args, nargs, value_type,
+				using_gcc, args, nargs, target_value_type,
 				&real_pc, &bp_addr);
 	  dummy_addr = sp;
 	}
@@ -440,7 +463,7 @@ call_function_by_hand (struct value *fun
 	{
 	  dummy_addr = sp;
 	  sp = push_dummy_code (current_gdbarch, sp, funaddr,
-				using_gcc, args, nargs, value_type,
+				using_gcc, args, nargs, target_value_type,
 				&real_pc, &bp_addr);
 	}
       break;
@@ -507,9 +530,15 @@ call_function_by_hand (struct value *fun
 	  param_type = TYPE_FIELD_TYPE (ftype, i);
 	else
 	  param_type = NULL;
-	
+
 	args[i] = value_arg_coerce (args[i], param_type, prototyped);
 
+	/* FIXME: Is current_language the right language?  */
+	if (current_language->la_language == language_cplus
+	    && param_type != NULL
+	    && cp_pass_by_reference (param_type))
+	  args[i] = value_addr (args[i]);
+
 	/* elz: this code is to handle the case in which the function
 	   to be called has a pointer to function as parameter and the
 	   corresponding actual argument is the address of a function
@@ -607,7 +636,7 @@ You must use a pointer to function type 
      stack, if necessary.  Make certain that the value is correctly
      aligned. */
 
-  if (struct_return)
+  if (struct_return || cp_struct_return)
     {
       int len = TYPE_LENGTH (value_type);
       if (INNER_THAN (1, 2))
@@ -632,6 +661,22 @@ You must use a pointer to function type 
 	}
     }
 
+  if (cp_struct_return)
+    {
+      struct value **new_args;
+
+      /* Add the new argument to the front of the argument list.  */
+      new_args = xmalloc (sizeof (struct value *) * (nargs + 1));
+      new_args[0] = value_from_pointer (lookup_pointer_type (value_type),
+					struct_addr);
+      memcpy (&new_args[1], &args[0], sizeof (struct value *) * nargs);
+      args = new_args;
+      nargs++;
+      args_cleanup = make_cleanup (xfree, args);
+    }
+  else
+    args_cleanup = make_cleanup (null_cleanup, NULL);
+
   /* Create the dummy stack frame.  Pass in the call dummy address as,
      presumably, the ABI code knows where, in the call dummy, the
      return address should be pointed.  */
@@ -649,6 +694,8 @@ You must use a pointer to function type 
   else
     error ("This target does not support function calls");
 
+  do_cleanups (args_cleanup);
+
   /* Set up a frame ID for the dummy frame so we can pass it to
      set_momentary_breakpoint.  We need to give the breakpoint a frame
      ID so that the breakpoint code can correctly re-identify the
@@ -839,11 +886,7 @@ the function call).", name);
   /* Figure out the value returned by the function, return that.  */
   {
     struct value *retval;
-    if (TYPE_CODE (value_type) == TYPE_CODE_VOID)
-      /* If the function returns void, don't bother fetching the
-	 return value.  */
-      retval = allocate_value (value_type);
-    else if (struct_return)
+    if (struct_return || cp_struct_return)
       /* NOTE: cagney/2003-09-27: This assumes that PUSH_DUMMY_CALL
 	 has correctly stored STRUCT_ADDR in the target.  In the past
 	 that hasn't been the case, the old MIPS PUSH_ARGUMENTS
@@ -853,6 +896,10 @@ the function call).", name);
 	 "struct return convention", check that PUSH_DUMMY_CALL isn't
 	 playing tricks.  */
       retval = value_at (value_type, struct_addr, NULL);
+    else if (TYPE_CODE (value_type) == TYPE_CODE_VOID)
+      /* If the function returns void, don't bother fetching the
+	 return value.  */
+      retval = allocate_value (value_type);
     else
       {
 	/* This code only handles "register convention".  */
Index: gdb-6.3/gdb/cp-abi.h
===================================================================
--- gdb-6.3.orig/gdb/cp-abi.h	2003-04-12 13:41:25.000000000 -0400
+++ gdb-6.3/gdb/cp-abi.h	2004-11-10 12:30:07.000000000 -0500
@@ -1,7 +1,7 @@
 /* Abstraction of various C++ ABI's we support, and the info we need
    to get from them.
    Contributed by Daniel Berlin <[e-mail]>
-   Copyright 2001 Free Software Foundation, Inc.
+   Copyright 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -145,6 +145,10 @@ extern struct type *value_rtti_type (str
 extern int baseclass_offset (struct type *type, int index, char *valaddr,
 			     CORE_ADDR address);
                   
+/* Return non-zero if an argument of type TYPE should be passed by reference
+   instead of value.  */
+extern int cp_pass_by_reference (struct type *type);
+
 struct cp_abi_ops
 {
   const char *shortname;
@@ -162,6 +166,7 @@ struct cp_abi_ops
 			     int *using_enc);
   int (*baseclass_offset) (struct type *type, int index, char *valaddr,
 			   CORE_ADDR address);
+  int (*pass_by_reference) (struct type *type);
 };
 
 
Index: gdb-6.3/gdb/cp-abi.c
===================================================================
--- gdb-6.3.orig/gdb/cp-abi.c	2003-11-26 17:04:00.000000000 -0500
+++ gdb-6.3/gdb/cp-abi.c	2004-11-10 12:30:07.000000000 -0500
@@ -1,5 +1,5 @@
 /* Generic code for supporting multiple C++ ABI's
-   Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
+   Copyright 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -94,6 +94,14 @@ value_rtti_type (struct value *v, int *f
   return (*current_cp_abi.rtti_type) (v, full, top, using_enc);
 }
 
+int
+cp_pass_by_reference (struct type *type)
+{
+  if ((current_cp_abi.pass_by_reference) == NULL)
+    return 0;
+  return (*current_cp_abi.pass_by_reference) (type);
+}
+
 /* Set the current C++ ABI to SHORT_NAME.  */
 
 static int
Index: gdb-6.3/gdb/gnu-v3-abi.c
===================================================================
--- gdb-6.3.orig/gdb/gnu-v3-abi.c	2004-03-15 15:38:08.000000000 -0500
+++ gdb-6.3/gdb/gnu-v3-abi.c	2004-11-10 12:30:07.000000000 -0500
@@ -1,7 +1,7 @@
 /* Abstraction of GNU v3 abi.