Re: Support for WEAK attribute, part 2

[Rimvydas Jasinskas <rimvydasjas@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 182 bytes --]

Thank you Harald, for the feedback!

Attached is part2 patch for weak variables support.  I'll post part3
patch for module-wide attribute support separately.

Best regards,
Rimvydas

[-- Attachment #2: 0001-Fortran-Add-support-for-WEAK-attribute-for-variables.patch --]
[-- Type: text/x-patch, Size: 6168 bytes --]

From fb1cf60d3fd7c6aa2d9787bb3af86f18e0178bf7 Mon Sep 17 00:00:00 2001
From: Rimvydas Jasinskas <rimvydas.jas@gmail.com>
Date: Thu, 23 Feb 2023 12:55:28 +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 or local variables.

gcc/testsuite/ChangeLog:

	* gfortran.dg/weak-2.f90: New test.
	* gfortran.dg/weak-3.f90: New test.
	* gfortran.dg/weak-4.f90: New test.
	* gfortran.dg/weak-5.f90: New test.
	* gfortran.dg/weak-6.f90: New test.
	* gfortran.dg/weak-7.f90: New test.
	* gfortran.dg/weak-8.f90: New test.

Signed-off-by: Rimvydas Jasinskas <rimvydas.jas@gmail.com>
---
 gcc/fortran/trans-decl.cc            |  9 +++++++++
 gcc/testsuite/gfortran.dg/weak-2.f90 |  9 +++++++++
 gcc/testsuite/gfortran.dg/weak-3.f90 |  9 +++++++++
 gcc/testsuite/gfortran.dg/weak-4.f90 | 10 ++++++++++
 gcc/testsuite/gfortran.dg/weak-5.f90 | 15 +++++++++++++++
 gcc/testsuite/gfortran.dg/weak-6.f90 |  6 ++++++
 gcc/testsuite/gfortran.dg/weak-7.f90 | 13 +++++++++++++
 gcc/testsuite/gfortran.dg/weak-8.f90 |  9 +++++++++
 8 files changed, 80 insertions(+)
 create mode 100644 gcc/testsuite/gfortran.dg/weak-2.f90
 create mode 100644 gcc/testsuite/gfortran.dg/weak-3.f90
 create mode 100644 gcc/testsuite/gfortran.dg/weak-4.f90
 create mode 100644 gcc/testsuite/gfortran.dg/weak-5.f90
 create mode 100644 gcc/testsuite/gfortran.dg/weak-6.f90
 create mode 100644 gcc/testsuite/gfortran.dg/weak-7.f90
 create mode 100644 gcc/testsuite/gfortran.dg/weak-8.f90

diff --git a/gcc/fortran/trans-decl.cc b/gcc/fortran/trans-decl.cc
index ff64588b9a8..24a85cf6043 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 +5889,11 @@ 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))
+	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");
+
       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..0c948640c89
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/weak-2.f90
@@ -0,0 +1,9 @@
+! { dg-do compile }
+! { dg-require-weak "" }
+! { dg-skip-if "" { x86_64-*-mingw* } }
+! { dg-skip-if "" { nvptx-*-* } }
+! { dg-final { scan-assembler "weak\[^ \t\]*\[ \t\]_?impl" } }
+integer function impl()
+implicit none
+!GCC$ ATTRIBUTES weak :: impl
+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..39ad299291b
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/weak-3.f90
@@ -0,0 +1,9 @@
+! { dg-do compile }
+! { dg-require-weak "" }
+! { dg-skip-if "" { x86_64-*-mingw* } }
+! { dg-skip-if "" { nvptx-*-* } }
+! { dg-final { scan-assembler "weak\[^ \t\]*\[ \t\]_?bar__" } }
+integer function impl() bind(c,name='bar__')
+implicit none
+!GCC$ ATTRIBUTES weak :: impl
+end function
diff --git a/gcc/testsuite/gfortran.dg/weak-4.f90 b/gcc/testsuite/gfortran.dg/weak-4.f90
new file mode 100644
index 00000000000..fef0233be8a
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/weak-4.f90
@@ -0,0 +1,10 @@
+! { dg-do compile }
+! { dg-require-weak "" }
+! { dg-skip-if "" { x86_64-*-mingw* } }
+! { dg-skip-if "" { nvptx-*-* } }
+! { dg-final { scan-assembler "weak\[^ \t\]*\[ \t\]_?__foo_MOD_abc" } }
+module foo
+implicit none
+!GCC$ ATTRIBUTES weak :: abc
+real :: abc(7)
+end module
diff --git a/gcc/testsuite/gfortran.dg/weak-5.f90 b/gcc/testsuite/gfortran.dg/weak-5.f90
new file mode 100644
index 00000000000..e48a8053570
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/weak-5.f90
@@ -0,0 +1,15 @@
+! { dg-do compile }
+! { dg-require-weak "" }
+! { dg-options "-Wall -Wextra" }
+module foo
+implicit none
+real :: a,b
+common /c/ a,b
+integer :: c
+! no error, common /c/ is not exported and variable 'c' has a mangled name
+!GCC$ ATTRIBUTES weak :: c
+contains
+ subroutine bar
+  c = 1
+ end subroutine
+end module
diff --git a/gcc/testsuite/gfortran.dg/weak-6.f90 b/gcc/testsuite/gfortran.dg/weak-6.f90
new file mode 100644
index 00000000000..bcdf4df78a6
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/weak-6.f90
@@ -0,0 +1,6 @@
+! { dg-do compile }
+! { dg-require-weak "" }
+program foo  ! { dg-error "weak declaration of 'foo' must be public" "" }
+implicit none
+!GCC$ ATTRIBUTES weak :: foo
+end program
diff --git a/gcc/testsuite/gfortran.dg/weak-7.f90 b/gcc/testsuite/gfortran.dg/weak-7.f90
new file mode 100644
index 00000000000..9f8f71c2f36
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/weak-7.f90
@@ -0,0 +1,13 @@
+! { dg-do compile }
+! { dg-require-weak "" }
+subroutine foo
+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
diff --git a/gcc/testsuite/gfortran.dg/weak-8.f90 b/gcc/testsuite/gfortran.dg/weak-8.f90
new file mode 100644
index 00000000000..d4bfe221312
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/weak-8.f90
@@ -0,0 +1,9 @@
+! { dg-do compile }
+! { dg-require-weak "" }
+subroutine foo(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