mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-27 07:31:35 +00:00
62 lines
1.3 KiB
C++
62 lines
1.3 KiB
C++
#include "Test.h"
|
|
|
|
/*
|
|
|
|
This test case is intended to check for one particular binutils/xcoff problem:
|
|
|
|
Without a patch, GNU ld fails to allocate space for weak uninitialized csects [BS],
|
|
and therefore puts both at the same address.
|
|
|
|
Minimal example:
|
|
|
|
.weak _one[BS]
|
|
.csect _one[BS]
|
|
_one:
|
|
.space 4
|
|
.weak _two[BS]
|
|
.csect _two[BS]
|
|
_two:
|
|
.space 4
|
|
|
|
|
|
powerpc-apple-macos-as test.s > test.o
|
|
powerpc-apple-macos-ld -r test.o -o linked.o
|
|
powerpc-apple-macos-objdump -t -h linked.o
|
|
|
|
Observe the size of the .bss section and the addresses of symbols _one and _two.
|
|
|
|
This test case tests for it using a thread-safe local static variable in an inline
|
|
function, which boils down to a pair of weakly-linked uninitialized csects as above.
|
|
|
|
*/
|
|
|
|
|
|
// noinline so that it doesn't get optimized away
|
|
__attribute__((noinline)) int foo()
|
|
{
|
|
return 42;
|
|
}
|
|
|
|
// the `inline` triggers a problem.
|
|
// the static var and its guard variable are marked `.weak`,
|
|
// and the XCOFF linker puts them at the same address.
|
|
inline int bar()
|
|
{
|
|
static int cachedFoo = foo();
|
|
return cachedFoo;
|
|
}
|
|
|
|
// wrap it in a noinline function to make reading the assembly easier.
|
|
__attribute__((noinline)) int baz()
|
|
{
|
|
return bar();
|
|
}
|
|
|
|
int main()
|
|
{
|
|
if (baz() != 42)
|
|
TestLog("NO");
|
|
else
|
|
TestLog("OK");
|
|
}
|