Re: Support for WEAK attribute, part 2

[Rimvydas Jasinskas <rimvydasjas@gmail.com>]

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On Thu, Feb 23, 2023 at 10:53 PM Harald Anlauf <anlauf@gmx.de> wrote:
> the patch is mostly fine, but there is a minor style issue:
>
> +      if (sym->attr.ext_attr & (1 << EXT_ATTR_WEAK))
> +       gfc_error ("Symbol %qs at %L has the WEAK attribute but is a %s",
> +                  sym->name, &sym->declared_at, sym->attr.dummy
> +                  ? "dummy argument" : "local variable");
> +
>
> It is my understanding that this is not translation-friendly.
> Please use separate error texts for either case instead.
Interesting, I was under the impression this was fixed with OO-inlines
around the *.c rename.  In any case, adjusted in v2 to use:
+      if (sym->attr.ext_attr & (1 << EXT_ATTR_WEAK))
+    {
+      if (sym->attr.dummy)
+        gfc_error ("Symbol %qs at %L has the WEAK attribute but is a "
+               "dummy argument", sym->name, &sym->declared_at);
+      else
+        gfc_error ("Symbol %qs at %L has the WEAK attribute but is a "
+               "local variable", sym->name, &sym->declared_at);
+    }

> Do we need to really have that many separate files for all
> the tests?  Note that each separate file contributes to the
> time developers wait on regtesting to complete.  Some of the
> files essentially test only minor variations, like weak-2.f90
> and weak-3.f90.
These testcases are dg-compile and do not go through the "-O0 -O1 -O2
-O3 -Os" options like dg-run.  Combining the testcases does not reduce
gfortran.sum a lot:
-PASS: gfortran.dg/weak-2.f90   -O   scan-assembler weak[^ \t]*[ \t]_?impl
-PASS: gfortran.dg/weak-2.f90   -O  (test for excess errors)
-PASS: gfortran.dg/weak-3.f90   -O   scan-assembler weak[^ \t]*[ \t]_?bar__
-PASS: gfortran.dg/weak-3.f90   -O  (test for excess errors)
-PASS: gfortran.dg/weak-4.f90   -O   scan-assembler weak[^ \t]*[
\t]_?__foo_MOD_abc
-PASS: gfortran.dg/weak-4.f90   -O  (test for excess errors)
-PASS: gfortran.dg/weak-5.f90   -O  (test for excess errors)
-PASS: gfortran.dg/weak-6.f90   -O   (test for errors, line 3)
-PASS: gfortran.dg/weak-6.f90   -O  (test for excess errors)
-PASS: gfortran.dg/weak-7.f90   -O   (test for errors, line 10)
-PASS: gfortran.dg/weak-7.f90   -O   (test for errors, line 6)
-PASS: gfortran.dg/weak-7.f90   -O  (test for excess errors)
-PASS: gfortran.dg/weak-8.f90   -O   (test for errors, line 3)
-PASS: gfortran.dg/weak-8.f90   -O   (test for errors, line 7)
-PASS: gfortran.dg/weak-8.f90   -O  (test for excess errors)
+PASS: gfortran.dg/weak-2.f90   -O   scan-assembler weak[^ \t]*[
\t]_?__foo_MOD_abc
+PASS: gfortran.dg/weak-2.f90   -O   scan-assembler weak[^ \t]*[ \t]_?bar__
+PASS: gfortran.dg/weak-2.f90   -O   scan-assembler weak[^ \t]*[ \t]_?impl1
+PASS: gfortran.dg/weak-2.f90   -O  (test for excess errors)
+PASS: gfortran.dg/weak-3.f90   -O   (test for errors, line 14)
+PASS: gfortran.dg/weak-3.f90   -O   (test for errors, line 18)
+PASS: gfortran.dg/weak-3.f90   -O   (test for errors, line 24)
+PASS: gfortran.dg/weak-3.f90   -O   (test for errors, line 28)
+PASS: gfortran.dg/weak-3.f90   -O   (test for errors, line 5)
+PASS: gfortran.dg/weak-3.f90   -O  (test for excess errors)

Only benefit is a bit less gfortran/f951 binaries invocations at
expense of potentially introducing issues in what was intended to be
tested.  There exists a partial(intentionally or not) sequential
file-scope namespace (like in C) how gfortran parses different units
in the same file.  Swapping unit order in the file can affect not only
code generation but diagnostic counts reported.  I tend to avoid
having more than one unit per source to avoid dealing with
"borrowing".  However with part3 now implemented after debugging, I
guess, samples could be combined to "accepts" + "rejects" two
testcases,  Done in v2.

> What is the purpose of testcase weak-5.f90?  It's valid
> Fortran, the common block /c/ shows in the assembler and
> does not interfere with the module variable c.
Removed.  Issue is not directly related to only the WEAK attributes.
Will be addressed in the future.

> Finally, please do not forget to CC patches to gcc-patches@
> so that others can see them.
Out of curiosity, what is the purpose of CC patches to gcc-patches
too?  Attachments are even available in web mailing list too, like in:
https://gcc.gnu.org/pipermail/fortran/2023-February/058953.html

Regards,
Rimvydas

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From 5b83226c714b17780334b5bad9b17c2266af8232 Mon Sep 17 00:00:00 2001
From: Rimvydas Jasinskas <rimvydas.jas@gmail.com>
Date: Fri, 24 Feb 2023 04:41:00 +0000
Subject: Fortran: Add support for WEAK attribute for variables

 Add the rest of the weak-*.f90 testcases.

gcc/fortran/ChangeLog:

	* trans-decl.cc (gfc_finish_var_decl): Apply attribute.
	(generate_local_decl): Add diagnostic for dummy and local variables.

gcc/testsuite/ChangeLog:

	* gfortran.dg/weak-2.f90: New test.
	* gfortran.dg/weak-3.f90: New test.

Signed-off-by: Rimvydas Jasinskas <rimvydas.jas@gmail.com>
---
 gcc/fortran/trans-decl.cc            | 14 +++++++++++++
 gcc/testsuite/gfortran.dg/weak-2.f90 | 26 ++++++++++++++++++++++++
 gcc/testsuite/gfortran.dg/weak-3.f90 | 30 ++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)
 create mode 100644 gcc/testsuite/gfortran.dg/weak-2.f90
 create mode 100644 gcc/testsuite/gfortran.dg/weak-3.f90

diff --git a/gcc/fortran/trans-decl.cc b/gcc/fortran/trans-decl.cc
index ff64588b9a8..474920966ec 100644
--- a/gcc/fortran/trans-decl.cc
+++ b/gcc/fortran/trans-decl.cc
@@ -814,6 +814,10 @@ gfc_finish_var_decl (tree decl, gfc_symbol * sym)
       && (TREE_STATIC (decl) || DECL_EXTERNAL (decl)))
     set_decl_tls_model (decl, decl_default_tls_model (decl));
 
+  /* Mark weak variables.  */
+  if (sym->attr.ext_attr & (1 << EXT_ATTR_WEAK))
+    declare_weak (decl);
+
   gfc_finish_decl_attrs (decl, &sym->attr);
 }
 
@@ -5885,6 +5889,16 @@ generate_local_decl (gfc_symbol * sym)
       if (!sym->attr.dummy && !sym->ns->proc_name->attr.entry_master)
 	generate_dependency_declarations (sym);
 
+      if (sym->attr.ext_attr & (1 << EXT_ATTR_WEAK))
+	{
+	  if (sym->attr.dummy)
+	    gfc_error ("Symbol %qs at %L has the WEAK attribute but is a "
+		       "dummy argument", sym->name, &sym->declared_at);
+	  else
+	    gfc_error ("Symbol %qs at %L has the WEAK attribute but is a "
+		       "local variable", sym->name, &sym->declared_at);
+	}
+
       if (sym->attr.referenced)
 	gfc_get_symbol_decl (sym);
 
diff --git a/gcc/testsuite/gfortran.dg/weak-2.f90 b/gcc/testsuite/gfortran.dg/weak-2.f90
new file mode 100644
index 00000000000..3e0e877e903
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/weak-2.f90
@@ -0,0 +1,26 @@
+! { dg-do compile }
+! { dg-require-weak "" }
+! { dg-skip-if "" { x86_64-*-mingw* } }
+! { dg-skip-if "" { nvptx-*-* } }
+
+! 1.
+! { dg-final { scan-assembler "weak\[^ \t\]*\[ \t\]_?__foo_MOD_abc" } }
+module foo
+implicit none
+!GCC$ ATTRIBUTES weak :: abc
+real :: abc(7)
+end module
+
+! 2.
+! { dg-final { scan-assembler "weak\[^ \t\]*\[ \t\]_?impl1" } }
+integer function impl1()
+implicit none
+!GCC$ ATTRIBUTES weak :: impl1
+end function
+
+! 3.
+! { dg-final { scan-assembler "weak\[^ \t\]*\[ \t\]_?bar__" } }
+integer function impl2() bind(c,name='bar__')
+implicit none
+!GCC$ ATTRIBUTES weak :: impl2
+end function
diff --git a/gcc/testsuite/gfortran.dg/weak-3.f90 b/gcc/testsuite/gfortran.dg/weak-3.f90
new file mode 100644
index 00000000000..cfa845921ff
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/weak-3.f90
@@ -0,0 +1,30 @@
+! { dg-do compile }
+! { dg-require-weak "" }
+
+! 1.
+program foo1  ! { dg-error "weak declaration of 'foo1' must be public" "" }
+implicit none
+!GCC$ ATTRIBUTES weak :: foo1
+end program
+
+! 2.
+subroutine foo2
+implicit none
+contains
+ function dar() ! { dg-error "weak declaration of 'dar' must be public" "" }
+ integer :: dar
+!GCC$ ATTRIBUTES weak :: dar
+ end function
+ subroutine bar ! { dg-error "weak declaration of 'bar' must be public" "" }
+!GCC$ ATTRIBUTES weak :: bar
+ end subroutine
+end subroutine
+
+! 3.
+subroutine foo3(n) ! { dg-error "has the WEAK attribute but is a dummy argument" "" }
+implicit none
+integer :: n
+!GCC$ ATTRIBUTES weak :: n
+real :: abc       ! { dg-error "has the WEAK attribute but is a local variable" "" }
+!GCC$ ATTRIBUTES weak :: abc
+end subroutine
-- 
2.39.2