binutils-gdb/ld/testsuite/ld-i386/pcrel16-2.s

	.text
	.global _start
_start:
	data16 xbegin t16
	ret

	.fill 0x8000,1,0xcc

	.global t16
t16:
	data16 xbegin _start
	ret
x86: correct overflow checking for 16-bit PC-relative relocs The only insn requiring a truly 16-bit PC-relative relocation outside of 16-bit mode is XBEGIN (with an operand size override). For it, the relocation generated should behave similar to 8- and (for 64-bit) 32-bit PC-relatives ones, i.e. be checked for a signed value to fit the field. This same mode is also correct for 16-bit code. Outside of 16-bit code, branches with operand size overrides act in a truly PC-relative way only when living in the low 32k of address space, as they truncate rIP to 16 bits. This can't be expressed by a PC-relative relocation. Putting in place a new testcase, I'd like to note that the two existing ones (pcrel16 and pcrel16abs) appear to be pretty pointless: They don't expect any error despite supposedly checking for overflow, and in fact there can't possibly be any error for the - former since gas doesn't emit any relocation in the first place there, - latter because the way the relocation gets expressed by gas doesn't allow the linker to notice the overflow; it should be detected by gas if at all, but see above (an error would be reported here for x86-64 afaict, but this test doesn't get re-used there). 2021-04-26 16:41:35 +08:00			`.text`
			`.global _start`
			`_start:`
			`data16 xbegin t16`
			`ret`

			`.fill 0x8000,1,0xcc`

			`.global t16`
			`t16:`
			`data16 xbegin _start`
			`ret`