[llvm-dev] (Thin)LTO llvm build

Tue Sep 27 14:00:06 PDT 2016

On Tue, Sep 27, 2016 at 8:37 PM, Teresa Johnson <tejohnson at google.com> wrote:

Just in case it's important, I'm using Arch Linux (and most Linux
distros these days) CFLAGS/CPPFLAGS/LDFLAGS, which are as follows:

$ grep FLAGS /etc/makepkg.conf
CPPFLAGS="-D_FORTIFY_SOURCE=2"
CFLAGS="-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong"
CXXFLAGS="-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong"
LDFLAGS="-Wl,-O1,--sort-common,--as-needed,-z,relro"

This is the same way Fedora or Arch linux would build clang, or any
other usual package for that matter.

The only uncommon thing I set is the macro -D_GLIBCXX_USE_CXX11_ABI=0,
which I use to avoid C++11 ABI chaos since g++5.x, although it's
probably safe to drop by now, especially when CXX=clang++. That's
g++-specific, so is irrelevant to the issue at hand.

> I wonder if there is a bug that was fixed. I have bootstrapped with
> ThinLTO with the 3.9 compiler, but not with LLDB and not with
> SHARED_LIBS=ON. I can try with an older 3.9 version.

As you seem to have faster hardware, I would appreciate a validation
before I embark on another >=3h build endavour.

> Not sure I followed that, but in essence you just want to make sure that
> llvm-ranlib and llvm-ar match the build compiler.

Sorry for the confusing description.

I build llvm and install it locally in my home dir somewhere
($PREFIX). After building llvm, I move that installation out of the
way before installing the new build in a now empty $PREFIX, but not
before prepending the moved-to PREFIX in $PATH, in case I need the old
toolchain during 'ninja install'.

Make more sense?

> I used ON to try to reproduce your issue, the OFF was a suggestion
> to avoid it as a workaround. I'm surprised your build defaults this
> to ON, according to http://llvm.org/docs/CMake.html it defaults to
> OFF.

Hmm, I will explicitly set it to OFF in the next build.

Is it expected for the .so files listed below to be created with
SHARED_LIB=OFF?

> This is from your SHARED_LIBS=OFF build I assume? With the build
> containing the DSO error I'm assuming BUILD_SHARED_LIBS=ON, which
> would mean this should be a .so.

One would expect so, but in fact it's with the flags I posted
yesterday, so I'm equally confused as to why there's no .so, but the
error

These are the DSO file in lib/:

$ ls lib/*.so
lib/BugpointPasses.so
lib/libclang.so
lib/libgomp.so
lib/libiomp5.so
lib/liblldb.so
lib/libLTO.so
lib/libomp.so
lib/LLVMgold.so
lib/LLVMHello.so
lib/LLVMPolly.so

I'll assume, given the existence of the various .so files, that
SHARED_LIBS=ON is the default and what's been configured.

Unless cmake's configure step somehow is responsible for nuking
libLLVMRUntimedyld.so, I don't know if it's supposed to exist yet in
the build plan (failed) so far.

> If this archive is from the build getting the DSO error then I'm
> confused about which DSO is giving the error. In that case what does
> the link line look like?

For easier reading, I've newlined the parameters.

[1/90] Linking CXX executable bin/lldb-3.9.1
FAILED: bin/lldb-3.9.1
: && $PREFIX/bin/clang++
-D_GLIBCXX_USE_CXX11_ABI=0
-O2
-pipe
-fstack-protector-strong
--param=ssp-buffer-size=4
-march=x86-64
-mtune=generic
-fPIC
-fvisibility-inlines-hidden
-Wall
-W
-Wno-unused-parameter
-Wwrite-strings
-Wcast-qual
-Wmissing-field-initializers
-pedantic
-Wno-long-long
-Wcovered-switch-default
-Wnon-virtual-dtor
-Wdelete-non-virtual-dtor
-Werror=date-time
-std=c++11
-fcolor-diagnostics
-ffunction-sections
-fdata-sections
-flto=thin
-Wno-deprecated-declarations
-Wno-unknown-pragmas
-Wno-strict-aliasing
-Wno-deprecated-register
-Wno-vla-extension
-O3
-DNDEBUG
-Wl,-O1,--sort-common,--as-needed,-z,relro,--hash-style=gnu
-flto=thin
-Wl,-allow-shlib-undefined
-Wl,-O3
-Wl,--gc-sections \
 tools/lldb/tools/driver/CMakeFiles/lldb.dir/Driver.cpp.o \
 tools/lldb/tools/driver/CMakeFiles/lldb.dir/Platform.cpp.o
-o bin/lldb-3.9.1
-lpthread
lib/liblldb.so.3.9.1
-Wl,--start-group
lib/liblldbBase.a
lib/liblldbBreakpoint.a
lib/liblldbCommands.a
lib/liblldbDataFormatters.a
lib/liblldbHost.a
lib/liblldbCore.a
lib/liblldbExpression.a
lib/liblldbInitialization.a
lib/liblldbInterpreter.a
lib/liblldbSymbol.a
lib/liblldbTarget.a
lib/liblldbUtility.a
lib/liblldbPluginDisassemblerLLVM.a
lib/liblldbPluginSymbolFileDWARF.a
lib/liblldbPluginSymbolFilePDB.a
lib/libLLVMDebugInfoPDB.a
lib/libLLVMDebugInfoCodeView.a
lib/liblldbPluginSymbolFileSymtab.a
lib/liblldbPluginDynamicLoaderStatic.a
lib/liblldbPluginDynamicLoaderPosixDYLD.a
lib/liblldbPluginDynamicLoaderHexagonDYLD.a
lib/liblldbPluginDynamicLoaderWindowsDYLD.a
lib/liblldbPluginCPlusPlusLanguage.a
lib/liblldbPluginGoLanguage.a
lib/liblldbPluginJavaLanguage.a
lib/liblldbPluginObjCLanguage.a
lib/liblldbPluginObjCPlusPlusLanguage.a
lib/liblldbPluginObjectFileELF.a
lib/liblldbPluginObjectFileJIT.a
lib/liblldbPluginSymbolVendorELF.a
lib/liblldbPluginObjectContainerBSDArchive.a
lib/liblldbPluginObjectContainerMachOArchive.a
lib/liblldbPluginProcessGDBRemote.a
lib/liblldbPluginProcessUtility.a
lib/liblldbPluginPlatformAndroid.a
lib/liblldbPluginPlatformGDB.a
lib/liblldbPluginPlatformFreeBSD.a
lib/liblldbPluginPlatformKalimba.a
lib/liblldbPluginPlatformLinux.a
lib/liblldbPluginPlatformNetBSD.a
lib/liblldbPluginPlatformPOSIX.a
lib/liblldbPluginPlatformWindows.a
lib/liblldbPluginPlatformMacOSX.a
lib/liblldbPluginDynamicLoaderMacOSXDYLD.a
lib/liblldbPluginUnwindAssemblyInstEmulation.a
lib/liblldbPluginUnwindAssemblyX86.a
lib/liblldbPluginAppleObjCRuntime.a
lib/liblldbPluginRenderScriptRuntime.a
lib/liblldbPluginLanguageRuntimeGo.a
lib/liblldbPluginLanguageRuntimeJava.a
lib/liblldbPluginCXXItaniumABI.a
lib/liblldbPluginABIMacOSX_arm.a
lib/liblldbPluginABIMacOSX_arm64.a
lib/liblldbPluginABIMacOSX_i386.a
lib/liblldbPluginABISysV_arm.a
lib/liblldbPluginABISysV_arm64.a
lib/liblldbPluginABISysV_i386.a
lib/liblldbPluginABISysV_x86_64.a
lib/liblldbPluginABISysV_hexagon.a
lib/liblldbPluginABISysV_ppc.a
lib/liblldbPluginABISysV_ppc64.a
lib/liblldbPluginABISysV_mips.a
lib/liblldbPluginABISysV_mips64.a
lib/liblldbPluginABISysV_s390x.a
lib/liblldbPluginInstructionARM.a
lib/liblldbPluginInstructionARM64.a
lib/liblldbPluginInstructionMIPS.a
lib/liblldbPluginInstructionMIPS64.a
lib/liblldbPluginObjectFilePECOFF.a
lib/liblldbPluginOSGo.a
lib/liblldbPluginOSPython.a
lib/liblldbPluginMemoryHistoryASan.a
lib/liblldbPluginInstrumentationRuntimeAddressSanitizer.a
lib/liblldbPluginInstrumentationRuntimeThreadSanitizer.a
lib/liblldbPluginSystemRuntimeMacOSX.a
lib/liblldbPluginProcessElfCore.a
lib/liblldbPluginJITLoaderGDB.a
lib/liblldbPluginExpressionParserClang.a
lib/liblldbPluginExpressionParserGo.a
lib/liblldbPluginProcessLinux.a
lib/liblldbPluginProcessPOSIX.a
-Wl,--end-group
lib/libclangCodeGen.a
lib/libLLVMBitWriter.a
lib/libLLVMCoverage.a
lib/libLLVMipo.a
lib/libLLVMVectorize.a
lib/libLLVMIRReader.a
lib/libLLVMAsmParser.a
lib/libLLVMInstrumentation.a
lib/libLLVMLinker.a
lib/libLLVMObjCARCOpts.a
lib/libLLVMObject.a
lib/libLLVMScalarOpts.a
lib/libLLVMInstCombine.a
lib/libLLVMTarget.a
lib/libLLVMTransformUtils.a
lib/libLLVMAnalysis.a
lib/libclangRewriteFrontend.a
lib/libclangFrontend.a
lib/libclangDriver.a
lib/libclangParse.a
lib/libLLVMMCParser.a
lib/libLLVMProfileData.a
lib/libLLVMOption.a
lib/libclangRewrite.a
lib/libclangSerialization.a
lib/libclangSema.a
lib/libclangAnalysis.a
lib/libclangEdit.a
lib/libclangAST.a
lib/libclangLex.a
lib/libclangBasic.a
lib/libLLVMMC.a
lib/libLLVMBitReader.a
lib/libLLVMCore.a
lib/libLLVMSupport.a
-lrt
-ldl
-lcurses
-lpthread
-lz
-lm
-Wl,-rpath,"\$ORIGIN/../lib