2010-07-12  Yao Qi  <yao@codesourcery.com>

	Merge from Sourcery G++ 4.4:
 
	2009-10-06  Paul Brook  <paul@codesourcery.com>
	Issue #3869
	gcc/
	* target.h (gcc_target): Add warn_func_result.
	* target-def.h (TARGET_WARN_FUNC_RESULT): Define and use.
	* tree-cfg.h (execute_warn_function_return): Use
	targetm.warn_func_result.
	* config/arm/arm.c (TARGET_WARN_FUNC_RESULT): Define.
	(arm_warn_func_result): New function.

	gcc/testuite/
	 * gcc.target/arm/naked-3.c: New test.

 2010-07-10  Sandra Loosemore  <sandra@codesourcery.com>
 
 	Backport from mainline:

=== modified file 'gcc/config/arm/arm.c'
--- old/gcc/config/arm/arm.c	2010-07-29 16:58:56 +0000
+++ new/gcc/config/arm/arm.c	2010-07-30 13:58:02 +0000
@@ -214,6 +214,7 @@
 static int arm_issue_rate (void);
 static void arm_output_dwarf_dtprel (FILE *, int, rtx) ATTRIBUTE_UNUSED;
 static bool arm_allocate_stack_slots_for_args (void);
+static bool arm_warn_func_result (void);
 static const char *arm_invalid_parameter_type (const_tree t);
 static const char *arm_invalid_return_type (const_tree t);
 static tree arm_promoted_type (const_tree t);
@@ -378,6 +379,9 @@
 #undef TARGET_TRAMPOLINE_ADJUST_ADDRESS
 #define TARGET_TRAMPOLINE_ADJUST_ADDRESS arm_trampoline_adjust_address
 
+#undef TARGET_WARN_FUNC_RESULT
+#define TARGET_WARN_FUNC_RESULT arm_warn_func_result
+
 #undef TARGET_DEFAULT_SHORT_ENUMS
 #define TARGET_DEFAULT_SHORT_ENUMS arm_default_short_enums
 
@@ -2008,6 +2012,14 @@
   return !IS_NAKED (arm_current_func_type ());
 }
 
+static bool
+arm_warn_func_result (void)
+{
+  /* Naked functions are implemented entirely in assembly, including the
+     return sequence, so suppress warnings about this.  */
+  return !IS_NAKED (arm_current_func_type ());
+}
+
 
 /* Output assembler code for a block containing the constant parts
    of a trampoline, leaving space for the variable parts.

=== modified file 'gcc/target-def.h'
--- old/gcc/target-def.h	2010-03-24 20:44:48 +0000
+++ new/gcc/target-def.h	2010-07-30 13:58:02 +0000
@@ -212,6 +212,10 @@
 #define TARGET_EXTRA_LIVE_ON_ENTRY hook_void_bitmap
 #endif
 
+#ifndef TARGET_WARN_FUNC_RESULT
+#define TARGET_WARN_FUNC_RESULT hook_bool_void_true
+#endif
+
 #ifndef TARGET_ASM_FILE_START_APP_OFF
 #define TARGET_ASM_FILE_START_APP_OFF false
 #endif
@@ -1020,6 +1024,7 @@
   TARGET_EMUTLS,				\
   TARGET_OPTION_HOOKS,				\
   TARGET_EXTRA_LIVE_ON_ENTRY,			\
+  TARGET_WARN_FUNC_RESULT,			\
   TARGET_UNWIND_TABLES_DEFAULT,			\
   TARGET_HAVE_NAMED_SECTIONS,			\
   TARGET_HAVE_SWITCHABLE_BSS_SECTIONS,		\

=== modified file 'gcc/target.h'
--- old/gcc/target.h	2010-03-27 10:27:39 +0000
+++ new/gcc/target.h	2010-07-30 13:58:02 +0000
@@ -1171,6 +1171,10 @@
      bits in the bitmap passed in. */
   void (*live_on_entry) (bitmap);
 
+  /* Return false if warnings about missing return statements or suspect
+     noreturn attributes should be suppressed for the current function.  */
+  bool (*warn_func_result) (void);
+
   /* True if unwinding tables should be generated by default.  */
   bool unwind_tables_default;
 

=== added file 'gcc/testsuite/gcc.target/arm/naked-3.c'
--- old/gcc/testsuite/gcc.target/arm/naked-3.c	1970-01-01 00:00:00 +0000
+++ new/gcc/testsuite/gcc.target/arm/naked-3.c	2010-07-30 13:58:02 +0000
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wall" } */
+/* Check that we do not get warnings about missing return statements
+   or bogus looking noreturn functions.  */
+int __attribute__((naked))
+foo(void)
+{
+  __asm__ volatile ("mov r0, #1\r\nbx lr\n");
+}
+
+int __attribute__((naked,noreturn))
+bar(void)
+{
+  __asm__ volatile ("frob r0\n");
+}

=== modified file 'gcc/tree-cfg.c'
--- old/gcc/tree-cfg.c	2010-03-16 12:31:38 +0000
+++ new/gcc/tree-cfg.c	2010-07-30 13:58:02 +0000
@@ -47,6 +47,7 @@
 #include "value-prof.h"
 #include "pointer-set.h"
 #include "tree-inline.h"
+#include "target.h"
 
 /* This file contains functions for building the Control Flow Graph (CFG)
    for a function tree.  */
@@ -7092,6 +7093,9 @@
   edge e;
   edge_iterator ei;
 
+  if (!targetm.warn_func_result())
+    return 0;
+
   /* If we have a path to EXIT, then we do return.  */
   if (TREE_THIS_VOLATILE (cfun->decl)
       && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)