Re: [gfortran, PR33269] Simplify FORMAT expressions before checking them

[Tobias Schlüter <tobias dot schlueter at physik dot uni-muenchen dot de>]

Now with patch attached.

Tobias Schlüter wrote:
> this patch is completely straightforward: call gfc_simplify_expr() on 
> the format string before checking its validity via 
> check_format_string().  This is done during resolutions, so the call to 
> gfc_simplify_expr() doesn't happen unduly early.  I also moved some 
> checks into check_format as they belonged there IMO.
>
> Built and tested on i386-darwin with clean testsuite runs except for the 
> known do_3.f90 failures and the ones I mentioned in my earlier mail.  Ok?
>
> Cheers,
> - Tobi

:ADDPATCH fortran:
2007-09-23  Tobias Schlüter  <tobi@gcc.gnu.org>

	PR fortran/33269
fortran/
	* io.c (check_format_string): Move NULL and constant checks into
	this function.
	(check_io_constraints): Call gfc_simplify_expr() before calling
	check_format_string().  Remove NULL and constant checks.
testsuite/
	* gfortran.dg/fmt_error_2.f90: New.

diff -r 52bb8e870295 gcc/fortran/io.c
--- a/gcc/fortran/io.c	Sat Sep 22 20:06:49 2007 +0900
+++ b/gcc/fortran/io.c	Sun Sep 23 15:39:13 2007 +0900
@@ -919,6 +919,9 @@ static try
 static try
 check_format_string (gfc_expr *e, bool is_input)
 {
+  if (!e || e->expr_type != EXPR_CONSTANT)
+    return SUCCESS;
+
   mode = MODE_STRING;
   format_string = e->value.character.string;
   return check_format (is_input);
@@ -2786,8 +2789,8 @@ if (condition) \
     }
 
   expr = dt->format_expr;
-  if (expr != NULL && expr->expr_type == EXPR_CONSTANT
-      && check_format_string (expr, k == M_READ) == FAILURE)
+  if (gfc_simplify_expr (expr, 0) == FAILURE
+      || check_format_string (expr, k == M_READ) == FAILURE)
     return MATCH_ERROR;
 
   return m;
diff -r 52bb8e870295 gcc/testsuite/gfortran.dg/fmt_error_2.f90
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gfortran.dg/fmt_error_2.f90	Sun Sep 23 15:39:13 2007 +0900
@@ -0,0 +1,35 @@
+! { dg-do compile }
+! PR 33269: we used to not simplify format strings before checking if
+! they were valid, leading to a missed error.
+
+IMPLICIT CHARACTER*5 (h-z)
+
+CHARACTER*5 f
+CHARACTER*5 bad, good
+parameter(bad="a", good="(a)")
+
+PRINT ('a'), "hello" ! { dg-error "Missing leading left parenthesis in format string" }
+WRITE (*, ("a")) "error"  ! { dg-error "Missing leading left parenthesis in format string" }
+
+PRINT 'a', "hello" ! { dg-error "Missing leading left parenthesis in format string" }
+WRITE (*, "a") "error"  ! { dg-error "Missing leading left parenthesis in format string" }
+WRITE (*, bad) "error"  ! { dg-error "Missing leading left parenthesis in format string" }
+
+PRINT 'a' // ', a', "err", "or"   ! { dg-error "Missing leading left parenthesis in format string" }
+
+PRINT '(' // 'a'  ! { dg-error "Unexpected end of format string in format string" }
+
+! the following are ok
+PRINT "(2f5.3)", bar, foo
+PRINT ' (a)', "hello"
+WRITE (*, " ((a))") "hello"
+print "(a" // ")", "all is fine"
+print good, "great"
+
+! verify that we haven't broken non-constant expressions
+f = "(f5.3)"
+print f, 3.14159
+print (f), 2.71813
+print implicitly_typed, "something"
+write (*, implicitly_typed_as_well) "something else"
+END