[lldb-dev] llvm changing line table info from DWARF 2 to DWARF 4

Thu Oct 20 02:25:51 PDT 2016

Our buildbot <http://lab.llvm.org:8011/builders/lldb-x86_64-ubuntu-14.04-cmake>
runs the test suite with a selection of compilers, one of which is
clang ToT (test3, test4). You should get an email from it if anything
breaks.

pl

On 20 October 2016 at 00:24, Eric Christopher via lldb-dev
<lldb-dev at lists.llvm.org> wrote:
>
>
> On Wed, Oct 19, 2016 at 4:21 PM Tim Hammerquist <penryu at gmail.com> wrote:
>>
>> On Wed, Oct 19, 2016 at 4:09 PM, Eric Christopher <echristo at gmail.com>
>> wrote:
>>>
>>>
>>> On Wed, Oct 19, 2016 at 3:34 PM Tim Hammerquist <penryu at gmail.com> wrote:
>>>>
>>>> I was mistaken.
>>>>
>>>> The system toolchain builds stage1 llvm, clang & co.
>>>> The system toolchain builds lldb containing the llvm/clang/etc bits.
>>>> The system toolchain builds gtest test programs.
>>>>
>>>> The stage1 compiler builds the python test inferiors.
>>>>
>>>
>>> OK, then it sounds like at least some of the test programs are built with
>>> the new compiler? IIRC the python test inferiors here are the programs that
>>> are the meat of the testsuite for lldb yes?
>>
>>
>> Yes, these programs set up an expected state, and the python testsuite
>> uses the lldb is used to debug these inferiors.
>>
>> So it looks like we want two scenarios:
>>
>> Scenario 1: build ToT lldb + llvm/clang/etc using Xcode toolchain; build
>> test programs AND inferiors using Xcode toolchain
>> Scenario 2: build ToT lldb + llvm/clang/etc using ToT compiler; build test
>> programs AND inferiors using ToT compiler
>>
>> Does that sound right?
>>
>> S1 is _nearly_ what we have now; it would only require modifying the
>> python test suite to build inferiors with the system compiler.
>>
>
> I'd think so. It makes sure that current lldb is going to continue to work
> with both new compilers as well as existing compilers and that current lldb
> is buildable with both current compilers and newer compilers.
>
> Thanks!
>
> -eric
>
>>
>> I can start looking at what's required to start S2. We've got some
>> hardware coming to make it easier to bring up.
>>
>> -Tim
>>
>>
>>> If so, then on check-in we should possibly see some difference on some
>>> bot if they all use the same general configuration.  I don't have a current
>>> checkout so I don't know if the default -g is used or if it's set to a
>>> different dwarf level. Currently it looks like clang will use dwarf4 by
>>> default with -g:
>>>
>>> echristo at dzur ~/tmp> ~/builds/build-llvm/bin/clang -c foo.c -o - -target
>>> x86_64-apple-macosx10.11 -g | llvm-dwarfdump - | grep version | grep -v
>>> clang
>>> 0x00000000: Compile Unit: length = 0x00000037 version = 0x0004
>>> abbr_offset = 0x0000 addr_size = 0x08 (next unit at 0x0000003b)
>>>          version: 2
>>>
>>> where the first line is the debug_info header and the second is the
>>> version in the line table.
>>>
>>> Ted/Greg: Relatedly, what brought this up was the vliw aspect with
>>> maximum_operations_per_instruction - it's being hard coded to 1 here and I'm
>>> not sure how we want to deal with that on hexagon? Currently it'll be hard
>>> set to 1 so line stepping will work as I imagine it currently does. That
>>> said, if we wanted to take advantage of it then that's different. Primarily
>>> I wasn't sure if Ted and folk had a debugger that did take advantage of it
>>> if it was there.
>>>
>>> Thanks!
>>>
>>> -eric
>>>
>>>>
>>>>
>>>> On Wed, Oct 19, 2016 at 3:28 PM, Eric Christopher <echristo at gmail.com>
>>>> wrote:
>>>>>
>>>>>
>>>>>
>>>>> On Wed, Oct 19, 2016 at 3:26 PM Tim Hammerquist <penryu at gmail.com>
>>>>> wrote:
>>>>>>
>>>>>> The LLDB job in llvm.org will build a stage1 RA with
>>>>>> llvm+clang+libcxx+compiler-rt using the system compiler, and use the new
>>>>>> compiler to build lldb.
>>>>>>
>>>>>> By default, this is kicked off automatically when a clang stage1 RA is
>>>>>> successful, but can be manually triggered to build HEAD, or any revision
>>>>>> desired.
>>>>>>
>>>>>> The python test suite (invoked with the xcodebuild target
>>>>>> lldb-python-test-suite) uses the newly built compiler to build its test
>>>>>> programs.
>>>>>>
>>>>>>
>>>>>> http://lab.llvm.org:8080/green/job/lldb_build_test/21202/consoleFull#console-section-4
>>>>>>
>>>>>> However, the gtest suite (target lldb-gtest) uses the system (Xcode
>>>>>> toolchain) compiler to build test programs.
>>>>>>
>>>>>>
>>>>>> http://lab.llvm.org:8080/green/job/lldb_build_test/21202/artifact/lldb/test_output.zip
>>>>>>
>>>>>
>>>>> This seems like something that should be fixed :)
>>>>>
>>>>> -eric
>>>>>
>>>>>>
>>>>>>
>>>>>> -Tim
>>>>>>
>>>>>> On Wed, Oct 19, 2016 at 2:36 PM, Eric Christopher <echristo at gmail.com>
>>>>>> wrote:
>>>>>>>
>>>>>>> From chatting with Tim it sounds like at least one lldb bot uses the
>>>>>>> ToT compiler - we should probably verify that not only does it use that to
>>>>>>> build lldb but uses it for the tests. That'll get us at least some testing
>>>>>>> here.
>>>>>>>
>>>>>>> -eric
>>>>>>>
>>>>>>>
>>>>>>> On Wed, Oct 19, 2016 at 12:55 PM Greg Clayton via lldb-dev
>>>>>>> <lldb-dev at lists.llvm.org> wrote:
>>>>>>>>
>>>>>>>> I believe we are good, but it would be good to verify via testing
>>>>>>>> once a compiler becomes available.
>>>>>>>>
>>>>>>>> Greg
>>>>>>>>
>>>>>>>> > On Oct 19, 2016, at 12:19 PM, Ted Woodward via lldb-dev
>>>>>>>> > <lldb-dev at lists.llvm.org> wrote:
>>>>>>>> >
>>>>>>>> > This might affect us. Do we handle it correctly?
>>>>>>>> >
>>>>>>>> > https://reviews.llvm.org/D16697
>>>>>>>> >
>>>>>>>> > --
>>>>>>>> > Qualcomm Innovation Center, Inc.
>>>>>>>> > The Qualcomm Innovation Center, Inc. is a member of Code Aurora
>>>>>>>> > Forum, a Linux Foundation Collaborative Project
>>>>>>>> >
>>>>>>>> > _______________________________________________
>>>>>>>> > lldb-dev mailing list
>>>>>>>> > lldb-dev at lists.llvm.org
>>>>>>>> > http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> lldb-dev mailing list
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>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Tim <penryu at gmail.com>
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Tim <penryu at gmail.com>
>>
>>
>>
>>
>> --
>> Tim <penryu at gmail.com>
>
>
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