[PATCH] Bug 9862

[Steven Bosscher <s dot bosscher at student dot tudelft dot nl>]

Global variables, bah.

The global variables current_function_returns_{value,null} in c-decl.c
are being re-used for the next function after expanding or deferring a
function.  But if these variables were set for an offending function,
and this function is deferred, the two variables don't have the
appropriate value anymore when expanding -- in fact, with
-finline-functions they will always have the value of the function that
was parsed last....

Proposed fix is to move the warnings from c_expand_body_1() to
finish_function().  Bootstrapped and regtested on i686-pc-linux-gnu with
only unrelated new regressions (in objc, "tree check: expected
tree_list, have translation_unit_decl").  Test cases go into gcc.dg.  OK
for mainline?  Also OK for 3.3?

Gr.
Steven

2003-07-13  Steven Bosscher  <steven@gcc.gnu.org>

        Bug 9862
        * c-decl.c (c_expand_body_1): Move warnings from here...
        (finish_function): ...to here.

Index: c-decl.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/c-decl.c,v
retrieving revision 1.404
diff -c -3 -p -r1.404 c-decl.c
*** c-decl.c	11 Jul 2003 08:33:03 -0000	1.404
--- c-decl.c	13 Jul 2003 10:32:07 -0000
*************** finish_function (int nested, int can_def
*** 6220,6225 ****
--- 6220,6259 ----
        && DECL_INLINE (fndecl))
      warning ("no return statement in function returning non-void");
  
+   /* With just -Wextra, complain only if function returns both with
+      and without a value.  */
+   if (extra_warnings
+       && current_function_returns_value
+       && current_function_returns_null)
+     warning ("this function may return with or without a value");
+ 
+   /* If requested, warn about function definitions where the function will
+      return a value (usually of some struct or union type) which itself will
+      take up a lot of stack space.  */
+ 
+   if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))
+     {
+       tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));
+ 
+       if (ret_type && TYPE_SIZE_UNIT (ret_type)
+ 	  && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST
+ 	  && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),
+ 				   larger_than_size))
+ 	{
+ 	  unsigned int size_as_int
+ 	    = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));
+ 
+ 	  if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)
+ 	    warning_with_decl (fndecl,
+ 			       "size of return value of `%s' is %u bytes",
+ 			       size_as_int);
+ 	  else
+ 	    warning_with_decl (fndecl,
+ 			       "size of return value of `%s' is larger than %d bytes",
+ 			       larger_than_size);
+ 	}
+     }
+ 
    /* Clear out memory we no longer need.  */
    free_after_parsing (cfun);
    /* Since we never call rest_of_compilation, we never clear
*************** c_expand_body_1 (tree fndecl, int nested
*** 6416,6455 ****
    /* Undo the GC context switch.  */
    if (nested_p)
      ggc_pop_context ();
- 
-   /* With just -Wextra, complain only if function returns both with
-      and without a value.  */
-   if (extra_warnings
-       && current_function_returns_value
-       && current_function_returns_null)
-     warning ("this function may return with or without a value");
- 
-   /* If requested, warn about function definitions where the function will
-      return a value (usually of some struct or union type) which itself will
-      take up a lot of stack space.  */
- 
-   if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))
-     {
-       tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));
- 
-       if (ret_type && TYPE_SIZE_UNIT (ret_type)
- 	  && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST
- 	  && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),
- 				   larger_than_size))
- 	{
- 	  unsigned int size_as_int
- 	    = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));
- 
- 	  if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)
- 	    warning_with_decl (fndecl,
- 			       "size of return value of `%s' is %u bytes",
- 			       size_as_int);
- 	  else
- 	    warning_with_decl (fndecl,
- 			       "size of return value of `%s' is larger than %d bytes",
- 			       larger_than_size);
- 	}
-     }
  
    if (DECL_SAVED_INSNS (fndecl) == 0 && ! nested_p
        && ! flag_inline_trees)
--- 6450,6455 ----

/* Bug 9862 -- Spurious warnings with -finline-functions.
   Copyright (C) 2003 Free Software Foundation Inc.  */

/* { dg-do compile } */
/* { dg-options "-O -finline-functions" } */

extern int i;
extern int foo (void);
extern int bar (void);

int foo (void)
{
  if( i ) return 0;
  else    return 1;
}			/* { dg-bogus "may return with or without value" } */

int bar (void)
{
  if( i ) return;
  else    return 1;
}			/* { dg-warning "may return with or without value" } */

/* Bug 9862 -- Spurious warnings with -finline-functions.
   Copyright (C) 2003 Free Software Foundation Inc.  */

/* { dg-do compile } */
/* { dg-options "-O -finline-functions" } */

extern int i;
extern int foo (void);
extern int bar (void);

int foo (void)
{
  if( i ) return;
  else    return 1;
}			/* { dg-warning "may return with or without value" } */

int bar (void)
{
  if( i ) return 0;
  else    return 1;
}