re PR target/34734 ([avr] attribute((progmem)) not handled properly in C++)

	PR target/34734
	* config/avr/avr.c (avr_handle_progmem_attribute): Move warning 
	about uninitialized data attributed 'progmem' from here...
	(avr_encode_section_info): ...to this new function.
	(TARGET_ENCODE_SECTION_INFO): New define.
	(avr_section_type_flags): For data in ".progmem.data", remove
	section flag SECTION_WRITE.

From-SVN: r175621

gcc/ChangeLog

 2011-06-29  Georg-Johann Lay  <avr@gjlay.de>
 	
+	PR target/34734
+	* config/avr/avr.c (avr_handle_progmem_attribute): Move warning 
+	about uninitialized data attributed 'progmem' from here...
+	(avr_encode_section_info): ...to this new function.
+	(TARGET_ENCODE_SECTION_INFO): New define.
+	(avr_section_type_flags): For data in ".progmem.data", remove
+	section flag SECTION_WRITE.
+
+2011-06-29  Georg-Johann Lay  <avr@gjlay.de>
+	
 	* config/avr/t-avr (LIB1ASMFUNCS): Add _mulhisi3, _umulhisi3,
 	_xmulhisi3_exit.
 	* config/avr/libgcc.S (_xmulhisi3_exit): New Function.

gcc/config/avr/avr.c

@@ -108,6 +108,7 @@ static void avr_function_arg_advance (cumulative_args_t, enum machine_mode,
 				      const_tree, bool);
 static bool avr_function_ok_for_sibcall (tree, tree);
 static void avr_asm_named_section (const char *name, unsigned int flags, tree decl);
+static void avr_encode_section_info (tree, rtx, int);
 
 /* Allocate registers from r25 to r8 for parameters for function calls.  */
 #define FIRST_CUM_REG 26
@@ -197,6 +198,8 @@ static const struct attribute_spec avr_attribute_table[] =
 
 #undef TARGET_ASM_INIT_SECTIONS
 #define TARGET_ASM_INIT_SECTIONS avr_asm_init_sections
+#undef TARGET_ENCODE_SECTION_INFO
+#define TARGET_ENCODE_SECTION_INFO avr_encode_section_info
 
 #undef TARGET_REGISTER_MOVE_COST
 #define TARGET_REGISTER_MOVE_COST avr_register_move_cost
@@ -4941,12 +4944,7 @@ avr_handle_progmem_attribute (tree *node, tree name,
 	}
       else if (TREE_STATIC (*node) || DECL_EXTERNAL (*node))
 	{
-	  if (DECL_INITIAL (*node) == NULL_TREE && !DECL_EXTERNAL (*node))
-	    {
-	      warning (0, "only initialized variables can be placed into "
-		       "program memory area");
-	      *no_add_attrs = true;
-	    }
+          *no_add_attrs = false;
 	}
       else
 	{
@@ -5153,10 +5151,35 @@ avr_section_type_flags (tree decl, const char *name, int reloc)
 		 ".noinit section");
     }
 
+  if (0 == strncmp (name, ".progmem.data", strlen (".progmem.data")))
+    flags &= ~SECTION_WRITE;
+  
   return flags;
 }
 
 
+/* Implement `TARGET_ENCODE_SECTION_INFO'.  */
+
+static void
+avr_encode_section_info (tree decl, rtx rtl ATTRIBUTE_UNUSED,
+                         int new_decl_p)
+{
+  /* In avr_handle_progmem_attribute, DECL_INITIAL is not yet
+     readily available, see PR34734.  So we postpone the warning
+     about uninitialized data in program memory section until here.  */
+   
+  if (new_decl_p
+      && decl && DECL_P (decl)
+      && NULL_TREE == DECL_INITIAL (decl)
+      && avr_progmem_p (decl, DECL_ATTRIBUTES (decl)))
+    {
+      warning (OPT_Wuninitialized,
+               "uninitialized variable %q+D put into "
+               "program memory area", decl);
+    }
+}
+
+
 /* Implement `TARGET_ASM_FILE_START'.  */
 /* Outputs some appropriate text to go at the start of an assembler
    file.  */