Version 5.0-rseq-20190423.1
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
rseq/selftests: x86: Work-around bogus gcc-8 optimisation
At least the following versions of gcc-8:
- gcc version 8.0.1 20180414 (experimental) [trunk revision 259383] (Ubuntu 8-20180414-1ubuntu2)
- gcc 8.2.0-7ubuntu1 (Ubuntu 18.10 (Cosmic)),
generate broken assembler with asm goto that have a thread-local storage
"m" input operand on both x86-32 and x86-64. For instance:
__thread int var;
static int fct(void)
{
asm goto ( "jmp %l[testlabel]\n\t"
: : [var] "m" (var) : : testlabel);
return 0;
testlabel:
return 1;
}
int main()
{
return fct();
}
% gcc-8 -O2 -o test-asm-goto test-asm-goto.c
/tmp/ccAdHJbe.o: In function `main':
test-asm-goto.c:(.text.startup+0x1): undefined reference to `.L2'
collect2: error: ld returned 1 exit status
% gcc-8 -m32 -O2 -o test-asm-goto test-asm-goto.c
/tmp/ccREsVXA.o: In function `main':
test-asm-goto.c:(.text.startup+0x1): undefined reference to `.L2'
collect2: error: ld returned 1 exit status
Work-around this compiler bug in the rseq-x86.h header by passing the
address of the __rseq_abi TLS as a register operand rather than using
the "m" input operand.
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90193
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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1 file changed
