[PATCH, v2] Fortran: detect blanks within literal constants in free-form mode [PR92805]

[Harald Anlauf <anlauf@gmx.de>]

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Hi Mikael,

Am 29.07.22 um 13:11 schrieb Mikael Morin:
> Hello,
> 
> Le 28/07/2022 à 22:11, Harald Anlauf via Fortran a écrit :
>> Dear all,
>>
>> in free-form mode, blanks are significant, so they cannot appear
>> in literal constants, especially not before or after the "_" that
>> separates the literal and the kind specifier.
>>
>> The initial patch from Steve addressed numerical literals, which
>> I completed by adjusting the parsing of string literals.
>>
>> Regtested on x86_64-pc-linux-gnu.  OK for mainline?
>>
> It looks correct, but I think we should continue to have the free vs 
> fixed form abstracted away from the parsing code.

yes, that makes sense.

> So, I suggest instead to remove the calls to gfc_gobble_whitespace in 
> match_string_constant,

Indeed, removing these simplifies the function and indeed works!

 > and use gfc_next_char instead of gfc_match_char
> in get_kind.

There is one important functionality in gfc_match_char(): it manages
the locus.  We would need then to add this explicitly to get_kind,
which does not look to me like a big improvement over the present
solution.  Otherwise I get test regressions.

> Mikael
> 

I've attached a revised version with improved match_string_constant().
What do you think?

Thanks,
Harald

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From f8e7c297b7c9e5a2b22185c7e0d638764c33aa71 Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Thu, 28 Jul 2022 22:07:02 +0200
Subject: [PATCH] Fortran: detect blanks within literal constants in free-form
 mode [PR92805]

gcc/fortran/ChangeLog:

	PR fortran/92805
	* primary.cc (get_kind): Do not skip over blanks in free-form mode.
	(match_string_constant): Likewise.

gcc/testsuite/ChangeLog:

	PR fortran/92805
	* gfortran.dg/literal_constants.f: New test.
	* gfortran.dg/literal_constants.f90: New test.

Co-authored-by: Steven G. Kargl <kargl@gcc.gnu.org>
---
 gcc/fortran/primary.cc                        | 19 +++++++--------
 gcc/testsuite/gfortran.dg/literal_constants.f | 20 ++++++++++++++++
 .../gfortran.dg/literal_constants.f90         | 24 +++++++++++++++++++
 3 files changed, 53 insertions(+), 10 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/literal_constants.f
 create mode 100644 gcc/testsuite/gfortran.dg/literal_constants.f90

diff --git a/gcc/fortran/primary.cc b/gcc/fortran/primary.cc
index 3f01f67cd49..604f98a8dd9 100644
--- a/gcc/fortran/primary.cc
+++ b/gcc/fortran/primary.cc
@@ -92,14 +92,21 @@ get_kind (int *is_iso_c)
 {
   int kind;
   match m;
+  char c;
 
   *is_iso_c = 0;
 
+  c = gfc_peek_ascii_char ();
+  if (gfc_current_form == FORM_FREE && gfc_is_whitespace (c))
+    return -2;
+
   if (gfc_match_char ('_') != MATCH_YES)
     return -2;
 
-  m = match_kind_param (&kind, is_iso_c);
-  if (m == MATCH_NO)
+  m = MATCH_NO;
+  c = gfc_peek_ascii_char ();
+  if ((gfc_current_form == FORM_FREE && gfc_is_whitespace (c))
+      || (m = match_kind_param (&kind, is_iso_c)) == MATCH_NO)
     gfc_error ("Missing kind-parameter at %C");
 
   return (m == MATCH_YES) ? kind : -1;
@@ -1074,17 +1081,9 @@ match_string_constant (gfc_expr **result)
       c = gfc_next_char ();
     }
 
-  if (c == ' ')
-    {
-      gfc_gobble_whitespace ();
-      c = gfc_next_char ();
-    }
-
   if (c != '_')
     goto no_match;
 
-  gfc_gobble_whitespace ();
-
   c = gfc_next_char ();
   if (c != '\'' && c != '"')
     goto no_match;
diff --git a/gcc/testsuite/gfortran.dg/literal_constants.f b/gcc/testsuite/gfortran.dg/literal_constants.f
new file mode 100644
index 00000000000..4d1f1b7eb4c
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/literal_constants.f
@@ -0,0 +1,20 @@
+! { dg-do compile }
+! { dg-options "-ffixed-form" }
+! PR fortran/92805 - blanks within literal constants in fixed-form mode
+
+      implicit none
+      integer, parameter :: ck = kind ("a")  ! default character kind
+      integer, parameter :: rk = kind (1.0)  ! default real kind
+      print *, 1_"abc"
+      print *, 1 _"abc"
+      print *, 1_ "abc"
+      print *, ck_"a"
+      print *, ck _"ab"
+      print *, ck_ "ab"
+      print *, 3.1415_4
+      print *, 3.1415 _4
+      print *, 3.1415_ 4
+      print *, 3.1415_rk
+      print *, 3.1415 _rk
+      print *, 3.1415_ rk
+      end
diff --git a/gcc/testsuite/gfortran.dg/literal_constants.f90 b/gcc/testsuite/gfortran.dg/literal_constants.f90
new file mode 100644
index 00000000000..f8908f9ad76
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/literal_constants.f90
@@ -0,0 +1,24 @@
+! { dg-do compile }
+! { dg-options "-ffree-form" }
+! PR fortran/92805 - blanks within literal constants in free-form mode
+
+      implicit none
+      integer, parameter :: ck = kind ("a")  ! default character kind
+      integer, parameter :: rk = kind (1.0)  ! default real kind
+      print *, 1_"abc"
+      print *, 1 _"abc"   ! { dg-error "Syntax error" }
+      print *, 1_ "abc"   ! { dg-error "Missing kind-parameter" }
+      print *, 1 _ "abc"  ! { dg-error "Syntax error" }
+      print *, ck_"a"
+      print *, ck _"ab"   ! { dg-error "Syntax error" }
+      print *, ck_ "ab"   ! { dg-error "Syntax error" }
+      print *, ck _ "ab"  ! { dg-error "Syntax error" }
+      print *, 3.1415_4
+      print *, 3.1415 _4  ! { dg-error "Syntax error" }
+      print *, 3.1415_ 4  ! { dg-error "Missing kind-parameter" }
+      print *, 3.1415 _ 4 ! { dg-error "Syntax error" }
+      print *, 3.1415_rk
+      print *, 3.1415 _rk ! { dg-error "Syntax error" }
+      print *, 3.1415_ rk ! { dg-error "Missing kind-parameter" }
+      print *, 3.141 _ rk ! { dg-error "Syntax error" }
+      end
-- 
2.35.3