[PATCH] D36351: [lld][ELF] Add profile guided section layout

Tue Dec 12 16:32:26 PST 2017

Thanks Michael. I finally got it working, and I observed a small
performance improvements (~1%) if I'm not wrong.

Michael, can you rebase the patch and upload it so that I can review your
changes on Phabricator? Please make sure you include all changes against
LLVM and lld in a single patch. For now, I uploaded it
https://reviews.llvm.org/D41142, but since this is your patch, you want to
upload this review request rather than adding comments to my clone patch.

On Tue, Dec 12, 2017 at 7:50 AM, Michael Spencer <bigcheesegs at gmail.com>
wrote:

> On Thu, Dec 7, 2017 at 4:13 PM, Rui Ueyama <ruiu at google.com> wrote:
>
>> Could you fork this and fix it for me so that I can build it in exactly
>> the same way as you do? I also saw a clang crash, but before reproducing
>> that error, I observed the other error that I reported to you, so I believe
>> this is not the last error that needs to be fixed to run it on my machine.
>>
>
> I've got it to work and found a bug in the process. Here're my changes.
>
> https://github.com/Bigcheese/llvm-project/commits/cgprofile
>
> - Michael Spencer
>
>
>>
>> On Thu, Dec 7, 2017 at 4:11 PM, Michael Spencer <bigcheesegs at gmail.com>
>> wrote:
>>
>>> This crash is unrelated to my patch. It fails the same way
>>> at eddbec369c44094d57400299c5245bfc390ebf66 .
>>>
>>> - Michael Spencer
>>>
>>> On Tue, Dec 5, 2017 at 8:17 PM, Rui Ueyama <ruiu at google.com> wrote:
>>>
>>>> Please check out this branch (https://github.com/rui314/llv
>>>> m-project/commits/cgprofile) and run `./build.sh`.
>>>>
>>>> On my machine, the script failed with the following error.
>>>>
>>>> : && /ssd/llvm-project-cgprofile/build/bin/bin/clang++  -fPIC
>>>> -fprofile-instr-use=/ssd/llvm-project-cgprofile/build/instrumented/default.profdata
>>>> -fvisibility-inlines-hidden -std=c++11 -Wall -W -Wno-unused-parameter
>>>> -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic
>>>> -Wno-long-long -Wnon-virtual-dtor -Wno-comment -fcolor-diagnostics -O3
>>>> -DNDEBUG  -Wl,-z,defs -Wl,-z,nodelete -fuse-ld=lld -Wl,--color-diagnostics
>>>>  -Wl,-rpath-link,/ssd/llvm-project-cgprofile/build/optimized/./lib
>>>> -Wl,-O3 -Wl,--gc-sections  -Wl,--version-script,/ssd/llvm
>>>> -project-cgprofile/build/optimized/tools/lto/LTO.exports -shared
>>>> -Wl,-soname,libLTO.so.6 -o lib/libLTO.so.6.0.0svn
>>>> tools/lto/CMakeFiles/LTO.dir/LTODisassembler.cpp.o
>>>> tools/lto/CMakeFiles/LTO.dir/lto.cpp.o  lib/libLLVMAArch64CodeGen.a
>>>> lib/libLLVMAArch64AsmParser.a lib/libLLVMAArch64AsmPrinter.a
>>>> lib/libLLVMAArch64Desc.a lib/libLLVMAArch64Disassembler.a
>>>> lib/libLLVMAArch64Info.a lib/libLLVMAArch64Utils.a
>>>> lib/libLLVMAMDGPUCodeGen.a lib/libLLVMAMDGPUAsmParser.a
>>>> lib/libLLVMAMDGPUAsmPrinter.a lib/libLLVMAMDGPUDesc.a
>>>> lib/libLLVMAMDGPUDisassembler.a lib/libLLVMAMDGPUInfo.a
>>>> lib/libLLVMAMDGPUUtils.a lib/libLLVMARMCodeGen.a lib/libLLVMARMAsmParser.a
>>>> lib/libLLVMARMAsmPrinter.a lib/libLLVMARMDesc.a
>>>> lib/libLLVMARMDisassembler.a lib/libLLVMARMInfo.a lib/libLLVMARMUtils.a
>>>> lib/libLLVMBPFCodeGen.a lib/libLLVMBPFAsmParser.a
>>>> lib/libLLVMBPFAsmPrinter.a lib/libLLVMBPFDesc.a
>>>> lib/libLLVMBPFDisassembler.a lib/libLLVMBPFInfo.a
>>>> lib/libLLVMHexagonCodeGen.a lib/libLLVMHexagonAsmParser.a
>>>> lib/libLLVMHexagonDesc.a lib/libLLVMHexagonDisassembler.a
>>>> lib/libLLVMHexagonInfo.a lib/libLLVMLanaiCodeGen.a
>>>> lib/libLLVMLanaiAsmParser.a lib/libLLVMLanaiAsmPrinter.a
>>>> lib/libLLVMLanaiDesc.a lib/libLLVMLanaiDisassembler.a
>>>> lib/libLLVMLanaiInfo.a lib/libLLVMMipsCodeGen.a lib/libLLVMMipsAsmParser.a
>>>> lib/libLLVMMipsAsmPrinter.a lib/libLLVMMipsDesc.a
>>>> lib/libLLVMMipsDisassembler.a lib/libLLVMMipsInfo.a
>>>> lib/libLLVMMSP430CodeGen.a lib/libLLVMMSP430AsmPrinter.a
>>>> lib/libLLVMMSP430Desc.a lib/libLLVMMSP430Info.a lib/libLLVMNVPTXCodeGen.a
>>>> lib/libLLVMNVPTXAsmPrinter.a lib/libLLVMNVPTXDesc.a lib/libLLVMNVPTXInfo.a
>>>> lib/libLLVMPowerPCCodeGen.a lib/libLLVMPowerPCAsmParser.a
>>>> lib/libLLVMPowerPCAsmPrinter.a lib/libLLVMPowerPCDesc.a
>>>> lib/libLLVMPowerPCDisassembler.a lib/libLLVMPowerPCInfo.a
>>>> lib/libLLVMSparcCodeGen.a lib/libLLVMSparcAsmParser.a
>>>> lib/libLLVMSparcAsmPrinter.a lib/libLLVMSparcDesc.a
>>>> lib/libLLVMSparcDisassembler.a lib/libLLVMSparcInfo.a
>>>> lib/libLLVMSystemZCodeGen.a lib/libLLVMSystemZAsmParser.a
>>>> lib/libLLVMSystemZAsmPrinter.a lib/libLLVMSystemZDesc.a
>>>> lib/libLLVMSystemZDisassembler.a lib/libLLVMSystemZInfo.a
>>>> lib/libLLVMX86CodeGen.a lib/libLLVMX86AsmParser.a
>>>> lib/libLLVMX86AsmPrinter.a lib/libLLVMX86Desc.a
>>>> lib/libLLVMX86Disassembler.a lib/libLLVMX86Info.a lib/libLLVMX86Utils.a
>>>> lib/libLLVMXCoreCodeGen.a lib/libLLVMXCoreAsmPrinter.a
>>>> lib/libLLVMXCoreDesc.a lib/libLLVMXCoreDisassembler.a
>>>> lib/libLLVMXCoreInfo.a lib/libLLVMBitReader.a lib/libLLVMCore.a
>>>> lib/libLLVMLTO.a lib/libLLVMMC.a lib/libLLVMMCDisassembler.a
>>>> lib/libLLVMSupport.a lib/libLLVMTarget.a lib/libLLVMAArch64Desc.a
>>>> lib/libLLVMAArch64AsmPrinter.a lib/libLLVMAArch64Info.a
>>>> lib/libLLVMAArch64Utils.a lib/libLLVMAMDGPUDesc.a
>>>> lib/libLLVMAMDGPUAsmPrinter.a lib/libLLVMAMDGPUInfo.a
>>>> lib/libLLVMAMDGPUUtils.a lib/libLLVMARMDesc.a lib/libLLVMARMAsmPrinter.a
>>>> lib/libLLVMARMUtils.a lib/libLLVMARMInfo.a lib/libLLVMBPFAsmPrinter.a
>>>> lib/libLLVMHexagonDesc.a lib/libLLVMHexagonInfo.a lib/libLLVMLanaiDesc.a
>>>> lib/libLLVMLanaiAsmPrinter.a lib/libLLVMLanaiInfo.a
>>>> lib/libLLVMMipsAsmPrinter.a lib/libLLVMMSP430AsmPrinter.a
>>>> lib/libLLVMNVPTXAsmPrinter.a lib/libLLVMPowerPCAsmPrinter.a
>>>> lib/libLLVMSparcAsmPrinter.a lib/libLLVMSystemZDesc.a
>>>> lib/libLLVMSystemZAsmPrinter.a lib/libLLVMSystemZInfo.a
>>>> lib/libLLVMGlobalISel.a lib/libLLVMX86AsmPrinter.a lib/libLLVMX86Utils.a
>>>> lib/libLLVMXCoreAsmPrinter.a lib/libLLVMAsmPrinter.a
>>>> lib/libLLVMDebugInfoCodeView.a lib/libLLVMDebugInfoMSF.a
>>>> lib/libLLVMSelectionDAG.a lib/libLLVMMCDisassembler.a
>>>> lib/libLLVMObjCARCOpts.a lib/libLLVMPasses.a lib/libLLVMCodeGen.a
>>>> lib/libLLVMTarget.a lib/libLLVMipo.a lib/libLLVMScalarOpts.a
>>>> lib/libLLVMVectorize.a lib/libLLVMBitWriter.a lib/libLLVMLinker.a
>>>> lib/libLLVMIRReader.a lib/libLLVMAsmParser.a lib/libLLVMInstCombine.a
>>>> lib/libLLVMInstrumentation.a lib/libLLVMTransformUtils.a
>>>> lib/libLLVMAnalysis.a lib/libLLVMObject.a lib/libLLVMBitReader.a
>>>> lib/libLLVMMCParser.a lib/libLLVMMC.a lib/libLLVMProfileData.a
>>>> lib/libLLVMCore.a lib/libLLVMBinaryFormat.a lib/libLLVMSupport.a -lrt -ldl
>>>> -ltinfo -lpthread -lz -lm lib/libLLVMDemangle.a
>>>> -Wl,-rpath,"\$ORIGIN/../lib" && :
>>>> /usr/local/bin/ld.lld: error: can't create dynamic relocation
>>>> R_X86_64_32S against local symbol in readonly segment; recompile object
>>>> files with -fPIC
>>>> >>> defined in lib/libLLVMAArch64CodeGen.a(AArch64AsmPrinter.cpp.o)
>>>> >>> referenced by AArch64AsmPrinter.cpp
>>>> >>>               AArch64AsmPrinter.cpp.o:(LLVMInitializeAArch64AsmPrinter)
>>>> in archive lib/libLLVMAArch64CodeGen.a
>>>>
>>>> /usr/local/bin/ld.lld: error: can't create dynamic relocation
>>>> R_X86_64_32S against local symbol in readonly segment; recompile object
>>>> files with -fPIC
>>>> >>> defined in lib/libLLVMAArch64CodeGen.a(AArch64AsmPrinter.cpp.o)
>>>> >>> referenced by AArch64AsmPrinter.cpp
>>>> >>>               AArch64AsmPrinter.cpp.o:(LLVMInitializeAArch64AsmPrinter)
>>>> in archive lib/libLLVMAArch64CodeGen.a
>>>>
>>>>
>>>> On Tue, Dec 5, 2017 at 6:38 PM, Rui Ueyama <ruiu at google.com> wrote:
>>>>
>>>>> On Mon, Dec 4, 2017 at 2:30 PM, Michael Spencer <bigcheesegs at gmail.com
>>>>> > wrote:
>>>>>
>>>>>> I've attached updated patches.
>>>>>>
>>>>>> I just tested these patches on Linux based on {llvm, clang,
>>>>>> compiler-rt, lld} as of r319686 and everything worked just fine with the
>>>>>> following steps:
>>>>>>
>>>>>> * Applied the patches.
>>>>>> * Built llvm, clang, compiler-rt and lld in a Release build.
>>>>>> (cgprofile-build)
>>>>>> * Built llvm, and lld in a Release build using the clang from
>>>>>> cgprofile-build with `-fprofile-instr-generate`. (instrumented-build)
>>>>>> * Ran `check-lld` on instrumented-build
>>>>>> * Ran `cgprofile-build/llvm-profdata merge
>>>>>> <PATH-TO-LLVM-SOURCE>/llvm-project/lld/test/ELF/default.profraw -o
>>>>>> default.profdata` in the instrumented-build directory
>>>>>>
>>>>>
>>>>> This step is wrong. `default.profraw` file does not exist in that
>>>>> directory.
>>>>>
>>>>> After fixing the path, I could follow the next step, but during the
>>>>> build with profile data, clang crashed.
>>>>>
>>>>> Looks like we wasted too much time just to reproduce one result on the
>>>>> other end. I'll write a shell script to do all these steps in a batch
>>>>> without human interaction so that we don't need to type in the commands by
>>>>> hand. I'll upload everything to github, so please wait for a while.
>>>>>
>>>>> * Built llvm, and lld in a Release build using the clang from
>>>>>> cgprofile-build with `-fprofile-instr-use=default.profdata`.
>>>>>> (cg-profile-optimized-build)
>>>>>> * Checked that the .o files from cg-profile-optimized-build had call
>>>>>> graph profiles using `cgprofile-build/llvm-readobj -elf-cg-profile`
>>>>>>
>>>>>> - Michael Spencer
>>>>>>
>>>>>> On Mon, Nov 27, 2017 at 9:11 PM, Michael Spencer <
>>>>>> bigcheesegs at gmail.com> wrote:
>>>>>>
>>>>>>> On Mon, Nov 27, 2017 at 9:07 PM, Davide Italiano <davide at freebsd.org
>>>>>>> > wrote:
>>>>>>>
>>>>>>>> Maybe this happens only on Linux? As far as I can tell the patch
>>>>>>>> has been developed on Windows entirely. Michael, have you tried linux?
>>>>>>>>
>>>>>>>
>>>>>>> It has been tested mostly on Linux.
>>>>>>>
>>>>>>> - Michael Spencer
>>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>> On Nov 27, 2017 9:05 PM, "Michael Spencer" <bigcheesegs at gmail.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> On Mon, Nov 27, 2017 at 5:44 PM, Rui Ueyama <ruiu at google.com>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>> I rebased the patches to HEAD and tried to use it again. When I
>>>>>>>>>> ran `bin/llvm-profdata merge default.profraw -o default.profdata`, it
>>>>>>>>>> creates almost empty default.profdata and it shrunk default.profraw. That
>>>>>>>>>> seems pretty odd to me. Michael, do you know what is going on?
>>>>>>>>>>
>>>>>>>>>> Before:
>>>>>>>>>>
>>>>>>>>>> -rw-r-----  1 ruiu eng  29M Nov 27 17:39 default.profraw
>>>>>>>>>>
>>>>>>>>>> After:
>>>>>>>>>>
>>>>>>>>>> -rw-r-----  1 ruiu eng  560 Nov 27 17:39 default.profdata
>>>>>>>>>> -rw-r-----  1 ruiu eng 2.2M Nov 27 17:39 default.profraw
>>>>>>>>>>
>>>>>>>>>> The rebased patch is available at https://reviews.llvm.org/D40534
>>>>>>>>>> .
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I'm not sure what the issue is without more information. My patch
>>>>>>>>> doesn't change how llvm profile information works, it only uses the data.
>>>>>>>>>
>>>>>>>>> - Michael Spencer
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Mon, Nov 27, 2017 at 2:01 PM, Davide Italiano <
>>>>>>>>>> davide at freebsd.org> wrote:
>>>>>>>>>>
>>>>>>>>>>> On Mon, Nov 27, 2017 at 1:49 PM, Rui Ueyama <ruiu at google.com>
>>>>>>>>>>> wrote:
>>>>>>>>>>> > I'm so sorry that I didn't respond in a timely manner. I'm
>>>>>>>>>>> reading it again
>>>>>>>>>>> > now.
>>>>>>>>>>> >
>>>>>>>>>>>
>>>>>>>>>>> No worries, definitely not your fault. The whole back and forth
>>>>>>>>>>> has
>>>>>>>>>>> been a little slow, but this has been around for almost 6 months
>>>>>>>>>>> now
>>>>>>>>>>> (and has been in development for much longer) so we should really
>>>>>>>>>>> decide whether we want to ship it or kill it :)
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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