diff options
| author | Jan Beulich <jbeulich@suse.com> | 2021-04-26 10:41:35 +0200 |
|---|---|---|
| committer | Jan Beulich <jbeulich@suse.com> | 2021-04-26 10:41:35 +0200 |
| commit | a7664973b24a242cd9ea17deb5eaf503065fc0bd (patch) | |
| tree | 4022b58da916ab136085e8e19bbaf812e438a678 /ld/testsuite/ld-x86-64 | |
| parent | 8fb8824599f37a726685197a1728e92bc7a953e5 (diff) | |
| download | gdb-a7664973b24a242cd9ea17deb5eaf503065fc0bd.zip gdb-a7664973b24a242cd9ea17deb5eaf503065fc0bd.tar.gz gdb-a7664973b24a242cd9ea17deb5eaf503065fc0bd.tar.bz2 | |
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).
Diffstat (limited to 'ld/testsuite/ld-x86-64')
| -rw-r--r-- | ld/testsuite/ld-x86-64/pcrel16-2.d | 5 | ||||
| -rw-r--r-- | ld/testsuite/ld-x86-64/x86-64.exp | 1 |
2 files changed, 6 insertions, 0 deletions
diff --git a/ld/testsuite/ld-x86-64/pcrel16-2.d b/ld/testsuite/ld-x86-64/pcrel16-2.d new file mode 100644 index 0000000..5346a5b --- /dev/null +++ b/ld/testsuite/ld-x86-64/pcrel16-2.d @@ -0,0 +1,5 @@ +#name: PCREL16 overflow (2) +#source: ../ld-i386/pcrel16-2.s +#ld: +#error: .*relocation truncated to fit: R_X86_64_PC16 .*t16.* +#error: .*relocation truncated to fit: R_X86_64_PC16 .*_start.* diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp index 877d6ba..269f70d 100644 --- a/ld/testsuite/ld-x86-64/x86-64.exp +++ b/ld/testsuite/ld-x86-64/x86-64.exp @@ -261,6 +261,7 @@ run_dump_test "abs-l1om" run_dump_test "apic" run_dump_test "pcrel8" run_dump_test "pcrel16" +run_dump_test "pcrel16-2" run_dump_test "tlsgd2" run_dump_test "tlsgd3" run_dump_test "tlsgd12" |