[llvm] r347476 - Reland test/MC/Mips/reloc-directive-label-offset.s

Thu Nov 22 12:05:02 PST 2018

On 22.11.18. 20:30, Roman Lebedev wrote:
> On Thu, Nov 22, 2018 at 10:24 PM Vladimir Stefanovic
> <vladimir.stefanovic at rt-rk.com> wrote:
>> Hi Roman,
>>
>> maybe I should have mentioned it in the commit message - I added this
>> test yesterday as part of
>> '[MC] Support labels as offsets in .reloc directive'
>> (https://reviews.llvm.org/D53990).
> Yes, i saw that.
>
>> It's only meant to check that relocations are present in the relocation
>> table with the properly resolved offset, their order in the table is not
>> this test's concern.
> But since no other test is failing, this is the first test to expose
> the issue, no?
> I can't tell whether that is a pre-existing bug, or it is only now
> being introduced though.
>
>> (It's legal to have more relocations at the same offset.)
> Which means it is the non-determinism that is the problem.
>
Although legal, I can't think of any real world use case of this 'feature'.
>> Regards,
>> Vladimir
> Roman.
Regards,
Vladimir
>> On 22.11.18. 19:27, Roman Lebedev wrote:
>>> On Thu, Nov 22, 2018 at 9:21 PM Vladimir Stefanovic via llvm-commits
>>> <llvm-commits at lists.llvm.org> wrote:
>>>> Author: vstefanovic
>>>> Date: Thu Nov 22 10:18:58 2018
>>>> New Revision: 347476
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=347476&view=rev
>>>> Log:
>>>> Reland test/MC/Mips/reloc-directive-label-offset.s
>>>>
>>>> The test was reverted because it failed on
>>>> llvm-clang-x86_64-expensive-checks-win builder, and that was because
>>>> -DEXPENSIVE_CHECKS adds randomness to llvm::sort(), affecting the order of
>>>> relocation table entries.
>>>> Modified the test to not have two relocations at the same offset.
>>> I don't know what i'm talking about, but i'm not sure this is the correct fix.
>>>
>>> Is it *legal* to have two relocations at the same offset?
>>> If no, then shouldn't such situation result in an error?
>>> If yes, then that bot exposed the issue it was designed to expose, and
>>> hardening the test simply hides it.
>>> I would have guessed that somewhere, the relocation should be stable_sort'ed?
>>>
>>> Or maybe i'm just wrong.
>>>
>>>> Added:
>>>>       llvm/trunk/test/MC/Mips/reloc-directive-label-offset.s
>>>>
>>>> Added: llvm/trunk/test/MC/Mips/reloc-directive-label-offset.s
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Mips/reloc-directive-label-offset.s?rev=347476&view=auto
>>>> ==============================================================================
>>>> --- llvm/trunk/test/MC/Mips/reloc-directive-label-offset.s (added)
>>>> +++ llvm/trunk/test/MC/Mips/reloc-directive-label-offset.s Thu Nov 22 10:18:58 2018
>>>> @@ -0,0 +1,75 @@
>>>> +# RUN: llvm-mc -triple mips-unknown-linux %s -show-encoding -target-abi=o32 \
>>>> +# RUN:     | FileCheck --check-prefixes=ASM,ASM-32 %s
>>>> +# RUN: llvm-mc -triple mips64-unknown-linux %s -show-encoding -target-abi=n32 \
>>>> +# RUN:     | FileCheck --check-prefixes=ASM,ASM-64 %s
>>>> +# RUN: llvm-mc -triple mips64-unknown-linux %s -show-encoding -target-abi=n64 \
>>>> +# RUN:     | FileCheck --check-prefixes=ASM,ASM-64 %s
>>>> +# RUN: llvm-mc -triple mips-unknown-linux %s -show-encoding -target-abi=o32 \
>>>> +# RUN:     -filetype=obj | llvm-readobj -r | FileCheck -check-prefix=OBJ-O32 %s
>>>> +# RUN: llvm-mc -triple mips64-unknown-linux %s -show-encoding -target-abi=n32 \
>>>> +# RUN:     -filetype=obj | llvm-readobj -r | FileCheck -check-prefix=OBJ-N32 %s
>>>> +# RUN: llvm-mc -triple mips64-unknown-linux %s -show-encoding -target-abi=n64 \
>>>> +# RUN:     -filetype=obj | llvm-readobj -r | FileCheck -check-prefix=OBJ-N64 %s
>>>> +
>>>> +  .text
>>>> +foo: # ASM-LABEL: foo:
>>>> +  nop
>>>> +1:
>>>> +  nop
>>>> +  .reloc 1b, R_MIPS_NONE, foo       # ASM-32: .reloc ($tmp0), R_MIPS_NONE, foo
>>>> +                                    # ASM-64: .reloc .Ltmp0, R_MIPS_NONE, foo
>>>> +  nop
>>>> +  .reloc 1f, R_MIPS_32, foo         # ASM-32: .reloc ($tmp1), R_MIPS_32, foo
>>>> +                                    # ASM-64: .reloc .Ltmp1, R_MIPS_32, foo
>>>> +1:
>>>> +  nop
>>>> +  .reloc 1f, R_MIPS_CALL16, foo     # ASM-32: .reloc ($tmp2), R_MIPS_CALL16, foo
>>>> +                                    # ASM-64: .reloc .Ltmp2, R_MIPS_CALL16, foo
>>>> +1:
>>>> +  nop
>>>> +  .reloc 2f, R_MIPS_GOT_DISP, foo   # ASM-32: .reloc ($tmp3), R_MIPS_GOT_DISP, foo
>>>> +                                    # ASM-64: .reloc .Ltmp3, R_MIPS_GOT_DISP, foo
>>>> +  nop
>>>> +
>>>> +  .reloc 3f, R_MIPS_GOT_PAGE, foo   # ASM-32: .reloc ($tmp4), R_MIPS_GOT_PAGE, foo
>>>> +                                    # ASM-64: .reloc .Ltmp4, R_MIPS_GOT_PAGE, foo
>>>> +  nop
>>>> +bar:
>>>> +  nop
>>>> +2:
>>>> +  nop
>>>> +3:
>>>> +  nop
>>>> +  .reloc bar, R_MIPS_GOT_OFST, foo  # ASM: .reloc bar, R_MIPS_GOT_OFST, foo
>>>> +  nop
>>>> +  .reloc foo, R_MIPS_32, foo        # ASM: .reloc foo, R_MIPS_32, foo
>>>> +  nop
>>>> +1:
>>>> +  nop
>>>> +
>>>> +# OBJ-O32-LABEL: Relocations [
>>>> +# OBJ-O32:           0x0 R_MIPS_32 .text 0x0
>>>> +# OBJ-O32-NEXT:      0x4 R_MIPS_NONE .text 0x0
>>>> +# OBJ-O32-NEXT:      0xC R_MIPS_32 .text 0x0
>>>> +# OBJ-O32-NEXT:      0x10 R_MIPS_CALL16 foo 0x0
>>>> +# OBJ-O32-NEXT:      0x1C R_MIPS_GOT_OFST .text 0x0
>>>> +# OBJ-O32-NEXT:      0x20 R_MIPS_GOT_DISP foo 0x0
>>>> +# OBJ-O32-NEXT:      0x24 R_MIPS_GOT_PAGE .text 0x0
>>>> +
>>>> +# OBJ-N32-LABEL: Relocations [
>>>> +# OBJ-N32:           0x4 R_MIPS_NONE .text 0x0
>>>> +# OBJ-N32-NEXT:      0x1C R_MIPS_GOT_OFST .text 0x0
>>>> +# OBJ-N32-NEXT:      0x0 R_MIPS_32 .text 0x0
>>>> +# OBJ-N32-NEXT:      0xC R_MIPS_32 .text 0x0
>>>> +# OBJ-N32-NEXT:      0x10 R_MIPS_CALL16 foo 0x0
>>>> +# OBJ-N32-NEXT:      0x20 R_MIPS_GOT_DISP foo 0x0
>>>> +# OBJ-N32-NEXT:      0x24 R_MIPS_GOT_PAGE .text 0x0
>>>> +
>>>> +# OBJ-N64-LABEL: Relocations [
>>>> +# OBJ-N64:           0x4 R_MIPS_NONE/R_MIPS_NONE/R_MIPS_NONE .text 0x0
>>>> +# OBJ-N64-NEXT:      0x1C R_MIPS_GOT_OFST/R_MIPS_NONE/R_MIPS_NONE .text 0x0
>>>> +# OBJ-N64-NEXT:      0x0 R_MIPS_32/R_MIPS_NONE/R_MIPS_NONE .text 0x0
>>>> +# OBJ-N64-NEXT:      0xC R_MIPS_32/R_MIPS_NONE/R_MIPS_NONE .text 0x0
>>>> +# OBJ-N64-NEXT:      0x10 R_MIPS_CALL16/R_MIPS_NONE/R_MIPS_NONE foo 0x0
>>>> +# OBJ-N64-NEXT:      0x20 R_MIPS_GOT_DISP/R_MIPS_NONE/R_MIPS_NONE foo 0x0
>>>> +# OBJ-N64-NEXT:      0x24 R_MIPS_GOT_PAGE/R_MIPS_NONE/R_MIPS_NONE .text 0x0
>>> Roman.
>>>
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