On Fri, Jun 14, 2024 at 4:31 PM John Hubbard jhubbard@nvidia.com wrote:
When building with clang, via:
make LLVM=1 -C tools/testing/selftests...there are several warnings, and an error. This fixes all of those and allows these tests to run and pass.
Fix linker error (undefined reference to memcpy) by providing a local version of memcpy.
clang complains about using this form:
if (g = h & 0xf0000000)
...so factor out the assignment into a separate step.
The code is passing a signed const char* to elf_hash(), which expects a const unsigned char *. There are several callers, so fix this at the source by allowing the function to accept a signed argument, and then converting to unsigned operations, once inside the function.
clang doesn't have __attribute__((externally_visible)) and generates a warning to that effect. Fortunately, gcc 12 and gcc 13 do not seem to require that attribute in order to build, run and pass tests here, so remove it.
Reviewed-by: Carlos Llamas cmllamas@google.com Reviewed-by: Edward Liaw edliaw@google.com Reviewed-by: Muhammad Usama Anjum usama.anjum@collabora.com Tested-by: Muhammad Usama Anjum usama.anjum@collabora.com Signed-off-by: John Hubbard jhubbard@nvidia.com
tools/testing/selftests/vDSO/parse_vdso.c | 16 +++++++++++----- .../selftests/vDSO/vdso_standalone_test_x86.c | 18 ++++++++++++++++-- 2 files changed, 27 insertions(+), 7 deletions(-)
diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c index 413f75620a35..4ae417372e9e 100644 --- a/tools/testing/selftests/vDSO/parse_vdso.c +++ b/tools/testing/selftests/vDSO/parse_vdso.c @@ -55,14 +55,20 @@ static struct vdso_info ELF(Verdef) *verdef; } vdso_info;
-/* Straight from the ELF specification. */ -static unsigned long elf_hash(const unsigned char *name) +/*
- Straight from the ELF specification...and then tweaked slightly, in order to
- avoid a few clang warnings.
- */
+static unsigned long elf_hash(const char *name) { unsigned long h = 0, g;
while (*name)
const unsigned char *uch_name = (const unsigned char *)name;while (*uch_name) {
h = (h << 4) + *name++;if (g = h & 0xf0000000)
h = (h << 4) + *uch_name++;g = h & 0xf0000000;if (g) h ^= g >> 24; h &= ~g; }diff --git a/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c b/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c index 8a44ff973ee1..27f6fdf11969 100644 --- a/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c +++ b/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c @@ -18,7 +18,7 @@
#include "parse_vdso.h"
-/* We need a libc functions... */ +/* We need some libc functions... */ int strcmp(const char *a, const char *b) { /* This implementation is buggy: it never returns -1. */ @@ -34,6 +34,20 @@ int strcmp(const char *a, const char *b) return 0; }
+/*
- The clang build needs this, although gcc does not.
- Stolen from lib/string.c.
- */
+void *memcpy(void *dest, const void *src, size_t count) +{
char *tmp = dest;const char *s = src;while (count--)*tmp++ = *s++;return dest;+}
/* ...and two syscalls. This is x86-specific. */ static inline long x86_syscall3(long nr, long a0, long a1, long a2) { @@ -70,7 +84,7 @@ void to_base10(char *lastdig, time_t n) } }
-__attribute__((externally_visible)) void c_main(void **stack) +void c_main(void **stack) { /* Parse the stack */ long argc = (long)*stack; -- 2.45.2
Hi John, Could you try re-submitting this series with the RESEND prefix?
Thanks, Edward