https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119854
Bug ID: 119854
Summary: nvptx offloading: omptests' 'xt-declare-target-ctors':
'unresolved symbol __dso_handle'
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Keywords: openacc, openmp
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: tschwinge at gcc dot gnu.org
CC: burnus at gcc dot gnu.org, jakub at gcc dot gnu.org,
vries at gcc dot gnu.org
Target Milestone: ---
Target: nvptx
For omptests' 'xt-declare-target-ctors'
(<https://github.com/doru1004/omptests/blob/main/xt-declare-target-ctors/test.cpp>),
nvptx offloading compilation currently fails due to:
unresolved symbol __dso_handle
collect2: error: ld returned 1 exit status
nvptx mkoffload: fatal error:
[...]/x86_64-pc-linux-gnu-accel-nvptx-none-gcc returned 1 exit status
GCN offloading compiles fine. I first thought GCN, via being
'OBJECT_FORMAT_ELF', would get a '__dso_handle' definition via
'libgcc/crtstuff.c':
#ifdef OBJECT_FORMAT_ELF
#if DEFAULT_USE_CXA_ATEXIT
/* Declare the __dso_handle variable. It should have a unique value
in every shared-object; in a main program its value is zero. The
object should in any case be protected. This means the instance
in one DSO or the main program is not used in another object. The
dynamic linker takes care of this.
If __cxa_atexit is not being used, __dso_handle will not be used and
doesn't need to be defined. */
#ifdef TARGET_LIBGCC_SDATA_SECTION
extern void *__dso_handle __attribute__ ((__section__
(TARGET_LIBGCC_SDATA_SECTION)));
#endif
#ifdef HAVE_GAS_HIDDEN
extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
#endif
#ifdef CRTSTUFFS_O
void *__dso_handle = &__dso_handle;
#else
void *__dso_handle = 0;
#endif
#endif /* DEFAULT_USE_CXA_ATEXIT */
..., but actually it doesn't, due to being '!DEFAULT_USE_CXA_ATEXIT'. (See
PR119853 "GCN, nvptx: Review 'DEFAULT_USE_CXA_ATEXIT'".) Instead, it's via
linker magic; running GCN offloading 'ld' with '--trace-symbol=__dso_handle':
./a.xamdgcn-amdhsa.mkoffload.hsaco-a.xamdgcn-amdhsa.mkoffload.2.o:
reference to __dso_handle
<internal>: definition of __dso_handle
(The '__dso_handle'-using code is per 'DEFAULT_USE_CXA_ATEXIT' powerpc64le and
x86_64 GNU/Linux host.)
