[lld] r227711 - [test] Add test for section groups and deadstrip

[Rui Ueyama]

I added --gc-sections and used it in your testcase. And... it crashed. :(

I guess the garbage collector reclaims live atoms. I wouldn't be surprised
because ELF reader has never been tested with garbage collection enabled.

On Thu, Feb 5, 2015 at 3:05 PM, Rui Ueyama <ruiu at google.com> wrote:

> Looks like the GNU driver doesn't support --gc-sections, and the
> gc-sections feature is turned off by default. So no section is removed as
> long as you are using the GNU driver.
>
> I think we first have to add that command line option to the driver to
> turn on the flag in the linking context. Whether turning on the flag is
> enough or not is that I don't know. We should just try.
>
> On Thu, Feb 5, 2015 at 2:53 PM, Rafael Espíndola <
> rafael.espindola at gmail.com> wrote:
>
>> I think this is testing for a gnu ld bug/limitation:
>>
>> With the attached testcase, gnu ld keeps zed and bar. Gold keeps only bar.
>>
>> lld keeps _start, bad, zed and produces wrong bindings :-(
>>
>>
>> On 1 February 2015 at 00:47, Shankar Easwaran <shankare at codeaurora.org>
>> wrote:
>> > Author: shankare
>> > Date: Sat Jan 31 23:47:02 2015
>> > New Revision: 227711
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=227711&view=rev
>> > Log:
>> > [test] Add test for section groups and deadstrip
>> >
>> > This adds a test that deadstrip should preserve the section group even
>> if there
>> > is only one reference to a function in the group.
>> >
>> > Added:
>> >     lld/trunk/test/core/sectiongroup-deadstrip.objtxt
>> >
>> > Added: lld/trunk/test/core/sectiongroup-deadstrip.objtxt
>> > URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/test/core/sectiongroup-deadstrip.objtxt?rev=227711&view=auto
>> >
>> ==============================================================================
>> > --- lld/trunk/test/core/sectiongroup-deadstrip.objtxt (added)
>> > +++ lld/trunk/test/core/sectiongroup-deadstrip.objtxt Sat Jan 31
>> 23:47:02 2015
>> > @@ -0,0 +1,92 @@
>> > +# Test for section group members be preserved even if there is a
>> > +# reference to only one functions in the group.
>> > +# RUN: lld -core --dead-strip %s | FileCheck %s
>> > +
>> > +#
>> > +# Test that section groups are parsed properly when there is a
>> reference to a
>> > +# group atom from outside a group.
>> > +#
>> > +
>> > +---
>> > +defined-atoms:
>> > +  - name:         entry
>> > +    dead-strip:   never
>> > +    references:
>> > +    - offset:          1
>> > +      kind:            pcrel32
>> > +      target:          d1
>> > +  - name:            f1
>> > +    scope:           global
>> > +    type:            code
>> > +  - name:            f2
>> > +    scope:           global
>> > +    type:            code
>> > +  - name:            g1
>> > +    scope:           global
>> > +    type:            code
>> > +  - name:            d1
>> > +    scope:           global
>> > +    type:            data
>> > +  - name:            g1
>> > +    scope:           global
>> > +    type:            group-comdat
>> > +    references:
>> > +      - kind:            group-child
>> > +        target:          f1
>> > +      - kind:            group-child
>> > +        target:          f2
>> > +      - kind:            group-child
>> > +        target:          d1
>> > +      - kind:            group-child
>> > +        target:          g1
>> > +  - name:            anotherfunction
>> > +    scope:           global
>> > +    type:            data
>> > +    references:
>> > +      - kind:            layout-before
>> > +        target:          f1
>> > +---
>> > +undefined-atoms:
>> > +    - name:              f1
>> > +      can-be-null:       never
>> > +...
>> > +
>> > +#CHECK: defined-atoms:
>> > +#CHECK:   - name:            g1
>> > +#CHECK:     ref-name:        [[PARENT:[a-zA-Z\.0-9_]+]]
>> > +#CHECK:     scope:           global
>> > +#CHECK:     type:            group-comdat
>> > +#CHECK:     references:
>> > +#CHECK:       - kind:            group-child
>> > +#CHECK:         offset:          0
>> > +#CHECK:         target:          [[GCHILDONE:[a-zA-Z\.0-9_]+]]
>> > +#CHECK:       - kind:            group-child
>> > +#CHECK:         offset:          0
>> > +#CHECK:         target:          [[GCHILDTWO:[a-zA-Z\.0-9_]+]]
>> > +#CHECK:       - kind:            group-child
>> > +#CHECK:         offset:          0
>> > +#CHECK:         target:          [[GCHILDTHREE:[a-zA-Z\.0-9_]+]]
>> > +#CHECK:       - kind:            group-child
>> > +#CHECK:         offset:          0
>> > +#CHECK:         target:          [[GCHILDFOUR:[a-zA-Z\.0-9_]+]]
>> > +#CHECK:   - name:            f1
>> > +#CHECK:     ref-name:        [[GCHILDONE]]
>> > +#CHECK:     scope:           global
>> > +#CHECK:   - name:            f2
>> > +#CHECK:     ref-name:        [[GCHILDTWO]]
>> > +#CHECK:     scope:           global
>> > +#CHECK:   - name:            d1
>> > +#CHECK:     ref-name:        [[GCHILDTHREE]]
>> > +#CHECK:     scope:           global
>> > +#CHECK:     type:            data
>> > +#CHECK:   - name:            g1
>> > +#CHECK:     ref-name:        [[GCHILDFOUR]]
>> > +#CHECK:     scope:           global
>> > +#CHECK:   - name:            anotherfunction
>> > +#CHECK:     scope:           global
>> > +#CHECK:     type:            data
>> > +#CHECK:     references:
>> > +#CHECK:       - kind:            layout-before
>> > +#CHECK:         offset:          0
>> > +#CHECK:         target:          [[GCHILDONE]]
>> > +#CHECK: ...
>> >
>> >
>> > _______________________________________________
>> > llvm-commits mailing list
>> > llvm-commits at cs.uiuc.edu
>> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150205/5f1f8911/attachment.html>