commit 391168ec03980e1cc8fb6d3e3c4b424819cd90cf
author Jerome Forissier <jerome@forissier.org> Mon Jun 15 09:52:25 2020 +0200
committer Jérôme Forissier <jerome@forissier.org> Mon Jun 15 17:34:16 2020 +0200
tree 0be95317a8b908c63364c5a49110154ebf803b94
parent 5eac193c3b068b87c6148cb2bfe2b1b56e6fd29a

regression 1023: workaround Clang optimization issue

When using Clang on HiKey (tested with 9.0.1 and 10.0.0), xtest 1023
fails with:

 * regression_1023 Test ELF initialization (.init_array)
 regression_1000.c:1860: Expression "op.params[0].value.a == 21" (12 == 21) is false
 regression_1000.c:1871: Expression "op.params[0].value.a == 213" (123 == 213) is false
   regression_1023 FAILED

The values indicate that the os_test_lib shared library is initialized
after the main application, which is not what we expect. In fact, the
reason for the failure is code elimination performed by Clang [1]. The
validity of this optimization is still unclear, but in any case it does
not concern the main things being tested, which is the invocation of
initialization functions when they exist. Therefore this commit applies
a workaround which effectively disables the problematic optimization.

Note: the issue can be reproduced on QEMU with CFLAGS_ta_arm32=-Os and
QEMUv8 with CFLAGS_ta_arm64="-Os -fno-common".

[1] http://lists.llvm.org/pipermail/llvm-dev/2020-June/thread.html#142192

Signed-off-by: Jerome Forissier <jerome@forissier.org>
Acked-by: Etienne Carriere <etienne.carriere@linaro.org>