https://gcc.gnu.org/g:737a5760bb24a0a945cc2c916ba452e3f0060c58
commit r15-8906-g737a5760bb24a0a945cc2c916ba452e3f0060c58
Author: Thomas Koenig <tkoe...@gcc.gnu.org>
Date: Tue Mar 25 18:42:30 2025 +0100
C prototypes for functions returning C function pointers.
This patch handles dumping prototypes for C functions returning
function pointers. For the test case
MODULE test
USE, INTRINSIC :: ISO_C_BINDING
CONTAINS
FUNCTION lookup(idx) BIND(C)
type(C_FUNPTR) :: lookup
integer(C_INT), VALUE :: idx
lookup = C_FUNLOC(x1)
END FUNCTION lookup
subroutine x1()
end subroutine x1
END MODULE test
the prototype is
void (*lookup (int idx)) ();
Regression-tested. Again no test case because I don't know how.
During testing, I also found that vtabs were dumped, this is
also corrected.
gcc/fortran/ChangeLog:
PR fortran/119419
* dump-parse-tree.cc (write_funptr_fcn): New function.
(write_type): Invoke it for C_FUNPTR.
(write_interop_decl): Do not dump vtabs.
Diff:
---
gcc/fortran/dump-parse-tree.cc | 26 +++++++++++++++++++++++---
1 file changed, 23 insertions(+), 3 deletions(-)
diff --git a/gcc/fortran/dump-parse-tree.cc b/gcc/fortran/dump-parse-tree.cc
index 1a15757b57be..9501bccb803b 100644
--- a/gcc/fortran/dump-parse-tree.cc
+++ b/gcc/fortran/dump-parse-tree.cc
@@ -4038,6 +4038,7 @@ static void write_interop_decl (gfc_symbol *);
static void write_proc (gfc_symbol *, bool);
static void show_external_symbol (gfc_gsymbol *, void *);
static void write_type (gfc_symbol *sym);
+static void write_funptr_fcn (gfc_symbol *);
/* Do we need to write out an #include <ISO_Fortran_binding.h> or not? */
@@ -4379,9 +4380,10 @@ write_type (gfc_symbol *sym)
{
gfc_component *c;
- /* Don't dump our iso c module. */
+ /* Don't dump our iso c module, nor vtypes. */
- if (sym->from_intmod == INTMOD_ISO_C_BINDING || sym->attr.flavor !=
FL_DERIVED)
+ if (sym->from_intmod == INTMOD_ISO_C_BINDING || sym->attr.flavor !=
FL_DERIVED
+ || sym->attr.vtype)
return;
fprintf (dumpfile, "typedef struct %s {\n", sym->name);
@@ -4495,6 +4497,18 @@ write_formal_arglist (gfc_symbol *sym, bool bind_c)
}
+/* Write out an interoperable function returning a function pointer. Better
+ handled separately. As we know nothing about the type, assume void.
+ Function ponters can be freely converted in C anyway. */
+
+static void
+write_funptr_fcn (gfc_symbol *sym)
+{
+ fprintf (dumpfile, "void (*%s (", sym->binding_label);
+ write_formal_arglist (sym, 1);
+ fputs (")) ();\n", dumpfile);
+}
+
/* Write out a procedure, including its arguments. */
static void
write_proc (gfc_symbol *sym, bool bind_c)
@@ -4552,7 +4566,13 @@ write_interop_decl (gfc_symbol *sym)
else if (sym->attr.flavor == FL_DERIVED)
write_type (sym);
else if (sym->attr.flavor == FL_PROCEDURE)
- write_proc (sym, true);
+ {
+ if (sym->ts.type == BT_DERIVED
+ && sym->ts.u.derived->intmod_sym_id == ISOCBINDING_FUNPTR)
+ write_funptr_fcn (sym);
+ else
+ write_proc (sym, true);
+ }
}
/* This section deals with dumping the global symbol tree. */
