test-ref-configs.pl fails with Clang

[simonbutcher]

Description

• Type: Bug
• Priority: Major

---

Bug

mbed TLS build:
Version: mbedtls-2.13.1

Executing test-ref-configs.pl with clang fails with a series of build errors.

Extract from the build.

  CC    x509/req_app.c
  Gen   test_suite_aes.ofb.c
  CC    test_suite_aes.ofb.c
suites/helpers.function:238:13: error: unused function 'hexify'
      [-Werror,-Wunused-function]
static void hexify( unsigned char *obuf, const unsigned char *ibuf, int len )
            ^
suites/helpers.function:292:23: error: unused function 'unhexify_alloc'
      [-Werror,-Wunused-function]
static unsigned char *unhexify_alloc( const char *ibuf, size_t *olen )
                      ^
suites/helpers.function:343:12: error: unused function 'rnd_zero_rand'
      [-Werror,-Wunused-function]
static int rnd_zero_rand( void *rng_state, unsigned char *output, size_t len )
           ^
suites/helpers.function:370:12: error: unused function 'rnd_buffer_rand'
      [-Werror,-Wunused-function]
static int rnd_buffer_rand( void *rng_state, unsigned char *output, size_t len )
           ^
suites/helpers.function:416:12: error: unused function 'rnd_pseudo_rand'
      [-Werror,-Wunused-function]
static int rnd_pseudo_rand( void *rng_state, unsigned char *output, size_t len )
           ^
5 errors generated.
Makefile:102: recipe for target 'test_suite_aes.ofb' failed
make[1]: *** [test_suite_aes.ofb] Error 1
Makefile:21: recipe for target 'tests' failed
make: *** [tests] Error 2
Failed to build: config-suite-b.h

[ciarmcom]

ARM Internal Ref: IOTSSL-2563

[simonbutcher]

This appears to be a duplicate of #1628. As that was raised first I'm closing this issue.

[gilles-peskine-arm]

Fundamentally the bug is in test-ref-configs.pl: it doesn't invoke make properly. It should run make CFLAGS='-Os -Werror', not make CFLAGS='-Os -Werror -Wall -Wextra'. Perhaps there's a bug in the makefile as well, but that's less clear to me: we run $(CC) $(LOCAL_CFLAGS) $(CFLAGS), should we invert the order of CFLAGS and LOCAL_CFLAGS?