https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118831
Bug ID: 118831
Summary: C function with variables arguments called from
fortran on ARM architecture
Product: gcc
Version: 14.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: jcldc13 at gmail dot com
Target Milestone: ---
On ARM architecture (in my case mac mini M4), When a fortran program call a
language C function with variables arguments, variables arguments are not
decoded correctly. I have encountered this issue on gcc-14 (ARM), but some
colleague have same pb since gcc-10 (ARM).
Here is a sample of code, fortran an C, to reproduce the bug
Fortran77 style code (main_va_arg.F) :
=======================================
program test_va_arg_fortran_2_c
implicit none
character sp*80
integer test_va_arg_f3, val_i,i
sp="hello world"//char(0)
val_i = 666
i=test_va_arg_f3(val_i,sp)
end
C code (func_va_arg.c) :
========================
#include <stdio.h>
#include <stdarg.h>
int test_va_arg_f3_(int * s1, ...)
{
va_list pa;
char * myval;
fprintf(stderr,"s1 [%d]\n",*s1);
va_start(pa, s1);
myval = (char *) va_arg(pa, char *);
fprintf(stderr,"myval [%s]\n",myval);
return 1;
}
Compilation on mac mini M4 (gcc-14) :
======================================
gcc-14 -c func_va_arg.c
gfortran-14 -o test_va_arg main_va_arg.F func_va_arg.o
Execution :
./test_va_arg
s1 [666]
myval [`k]
As we can see, myval variable does not get the right value, it should be "hello
world",
The same code executed on X86-64 architecture (Linux and mac) works perfectly.
Here is the complete description of the compilers:
gcc-14 :
========
gcc-14 -v
Using built-in specs.
COLLECT_GCC=gcc-14
COLLECT_LTO_WRAPPER=/opt/homebrew/Cellar/gcc/14.2.0_1/bin/../libexec/gcc/aarch64-apple-darwin24/14/lto-wrapper
Target: aarch64-apple-darwin24
Configured with: ../configure --prefix=/opt/homebrew/opt/gcc
--libdir=/opt/homebrew/opt/gcc/lib/gcc/current --disable-nls
--enable-checking=release --with-gcc-major-version-only
--enable-languages=c,c++,objc,obj-c++,fortran,m2 --program-suffix=-14
--with-gmp=/opt/homebrew/opt/gmp --with-mpfr=/opt/homebrew/opt/mpfr
--with-mpc=/opt/homebrew/opt/libmpc --with-isl=/opt/homebrew/opt/isl
--with-zstd=/opt/homebrew/opt/zstd --with-pkgversion='Homebrew GCC 14.2.0_1'
--with-bugurl=https://github.com/Homebrew/homebrew-core/issues
--with-system-zlib --build=aarch64-apple-darwin24
--with-sysroot=/Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 14.2.0 (Homebrew GCC 14.2.0_1)
gfortran-14 :
=============
gfortran-14 -v
Using built-in specs.
COLLECT_GCC=gfortran-14
COLLECT_LTO_WRAPPER=/opt/homebrew/Cellar/gcc/14.2.0_1/bin/../libexec/gcc/aarch64-apple-darwin24/14/lto-wrapper
Target: aarch64-apple-darwin24
Configured with: ../configure --prefix=/opt/homebrew/opt/gcc
--libdir=/opt/homebrew/opt/gcc/lib/gcc/current --disable-nls
--enable-checking=release --with-gcc-major-version-only
--enable-languages=c,c++,objc,obj-c++,fortran,m2 --program-suffix=-14
--with-gmp=/opt/homebrew/opt/gmp --with-mpfr=/opt/homebrew/opt/mpfr
--with-mpc=/opt/homebrew/opt/libmpc --with-isl=/opt/homebrew/opt/isl
--with-zstd=/opt/homebrew/opt/zstd --with-pkgversion='Homebrew GCC 14.2.0_1'
--with-bugurl=https://github.com/Homebrew/homebrew-core/issues
--with-system-zlib --build=aarch64-apple-darwin24
--with-sysroot=/Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 14.2.0 (Homebrew GCC 14.2.0_1)
