This relocation is similar to R_*_RELATIVE except that the value used in this relocation is the program address returned by the function, which takes no arguments, at the address of
the result of the corresponding R_*_RELATIVE relocation as specified in the processor-specific ABI. The purpose of this relocation to avoid name lookup for locally defined STT_GNU_IFUNC symbols at load-time.
More info can be found in ifunc.txt from https://sites.google.com/site/x32abi/documents.
Testing can be performed using following sample:
#include <stdio.h>
int myfunc1() { return 1; }
int myfunc2() { return 2; }
// Prototype for the common entry point
extern "C" int myfunc();
__asm__ (".type myfunc, @gnu_indirect_function");
// Make the dispatcher function. This returns a pointer to the desired function version
typeof(myfunc) * myfunc_dispatch (void) __asm__ ("myfunc");
typeof(myfunc) * myfunc_dispatch (void) {
if (0)
return &myfunc1;
else
return &myfunc2;
}
int main() {
printf("\nCalled function number %i\n", myfunc());
return 0;
}~/LLVM/build/bin/clang -fuse-ld=lld -O0 -g test.cpp -o test
./test
Depending on if() condition 1 or 2 should appear in output.
} else if (Body && isGnuIfunc<ELFT>(*Body)) { P->setSymbolAndType(0, Target->getIRelativeReloc(), Config->Mips64EL); } else { P->setSymbolAndType(0, Target->getRelativeReloc(), Config->Mips64EL); }