[Patch, Fortran] PR 45044 - Named common: Different size diagnostics

[Patch, Fortran] PR 45044 - Named common: Different size diagnostics

[Tobias Burnus]

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Named common blocks are required to have the same size in all files and 
scopes. gfortran was warning before when the size was extended, but not 
when a smaller common block followed a larger common block with the same 
name.

This patch adds now a non-equal check and also mentions the byte size. I 
was thinking of adding another ref to point to the first common block, 
but my approach did not work (cf. PR comment 4) - besides, I find error 
messages with two loci harder to read.

Build and regtested on x86-64-linux.
OK for the trunk?

Tobias

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2011-08-30  Tobias Burnus  <burnus@net-b.de>

	PR fortran/45044
	* trans-common.c (build_common_decl): Warn if named common
	block's size is not everywhere the same.

2011-08-30  Tobias Burnus  <burnus@net-b.de>

	PR fortran/45044
	* gfortran.dg/common_14.f90: New.

diff --git a/gcc/fortran/trans-common.c b/gcc/fortran/trans-common.c
index c289bbe..21237c8 100644
--- a/gcc/fortran/trans-common.c
+++ b/gcc/fortran/trans-common.c
@@ -390,14 +390,20 @@ build_common_decl (gfc_common_head *com, tree union_type, bool is_init)
   if (decl != NULL_TREE)
     {
       tree size = TYPE_SIZE_UNIT (union_type);
+
+      /* Named common blocks of the same name shall be of the same size
+	 in all scoping units of a program in which they appear, but
+	 blank common blocks may be of different sizes.  */
+      if (!tree_int_cst_equal (DECL_SIZE_UNIT (decl), size)
+	  && strcmp (com->name, BLANK_COMMON_NAME))
+	gfc_warning ("Named COMMON block '%s' at %L shall be of the "
+		     "same size as elsewhere (%lu vs %lu bytes)", com->name,
+		     &com->where,
+		     (unsigned long) TREE_INT_CST_LOW (size),
+		     (unsigned long) TREE_INT_CST_LOW (DECL_SIZE_UNIT (decl)));
+
       if (tree_int_cst_lt (DECL_SIZE_UNIT (decl), size))
-        {
-	  /* Named common blocks of the same name shall be of the same size
-	     in all scoping units of a program in which they appear, but
-	     blank common blocks may be of different sizes.  */
-	  if (strcmp (com->name, BLANK_COMMON_NAME))
-	    gfc_warning ("Named COMMON block '%s' at %L shall be of the "
-			 "same size", com->name, &com->where);
+	{
 	  DECL_SIZE (decl) = TYPE_SIZE (union_type);
 	  DECL_SIZE_UNIT (decl) = size;
 	  DECL_MODE (decl) = TYPE_MODE (union_type);
--- /dev/null	2011-08-26 08:04:10.762940730 +0200
+++ gcc/gcc/testsuite/gfortran.dg/common_14.f90	2011-08-30 23:25:14.000000000 +0200
@@ -0,0 +1,27 @@
+! { dg-do compile }
+!
+! PR fortran/45044
+!
+! Named common blocks need to be all of the same size
+! check that the compiler warns for those.
+
+module m
+  common /xx/ a
+end module m
+
+subroutine two()
+integer :: a, b, c
+real(8) :: y
+common /xx/ a, b, c, y ! { dg-warning "Named COMMON block 'xx' at \\(1\\) shall be of the same size as elsewhere \\(24 vs 4 bytes" }
+end
+
+
+subroutine one()
+integer :: a, b
+common /xx/ a, b ! { dg-warning "Named COMMON block 'xx' at \\(1\\) shall be of the same size as elsewhere \\(8 vs 24 bytes" }
+end
+
+call two()
+end
+
+! { dg-final { cleanup-modules "m" } }

Re: [Patch, Fortran] PR 45044 - Named common: Different size diagnostics

[Steve Kargl]

On Tue, Aug 30, 2011 at 11:31:38PM +0200, Tobias Burnus wrote:
> Named common blocks are required to have the same size in all files and 
> scopes. gfortran was warning before when the size was extended, but not 
> when a smaller common block followed a larger common block with the same 
> name.
> 
> This patch adds now a non-equal check and also mentions the byte size. I 
> was thinking of adding another ref to point to the first common block, 
> but my approach did not work (cf. PR comment 4) - besides, I find error 
> messages with two loci harder to read.
> 
> Build and regtested on x86-64-linux.
> OK for the trunk?
> 

Looks ok to me.  

-- 
Steve