The Swift build fails because libcmark-gfm is not compiled with the -fPIC (position-independent code) flag.

[bc-lee]

While compiling the Swift main branch as of 2024-07-12 on Fedora 40, I encountered the following error:

Details

/usr/bin/clang++ -fPIC -Wno-unknown-warning-option -Werror=unguarded-availability-new -fno-stack-protector -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-class-memaccess -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -Wl,--version-script,"/path/to/swift/build/buildbot_linux/swift-linux-x86_64/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc.exports"  -target x86_64-unknown-linux-gnu -fuse-ld=gold -Xlinker --build-id=sha1 -shared -Wl,-soname,libsourcekitdInProc.so -o lib/libsourcekitdInProc.so tools/SourceKit/tools/sourcekitd/bin/InProc/CMakeFiles/sourcekitdInProc.dir/sourcekitdInProc.cpp.o -L/path/to/swift/build/buildbot_linux/llvm-linux-x86_64/./lib   -L/path/to/swift/build/buildbot_linux/swift-linux-x86_64/libdispatch-linux-x86_64-prefix/lib   -L/usr/lib/swift/linux   -L/usr/lib/swift/linux/x86_64   -L/path/to/swift/build/buildbot_linux/swift-linux-x86_64/lib -Wl,-rpath,"\$ORIGIN/swift/linux:\$ORIGIN/swift/host/compiler"  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMSupport.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMCoverage.a  /usr/lib/swift/linux/x86_64/swiftrt.o  -lswiftCore  -lpthread  -ldl  lib/libSourceKitSwiftLang.a  lib/libsourcekitdAPI.a  lib/libsourcekitdService.a  lib/libswiftIDETool.a  lib/libSourceKitSwiftLang.a  lib/libswiftIDETool.a  lib/libswiftFrontendTool.a  lib/libswiftDependencyScan.a  lib/libswiftDependencyScanImpl.a  lib/libswiftImmediate.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMMCJIT.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMOrcJIT.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMExecutionEngine.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMRuntimeDyld.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMJITLink.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMOrcTargetProcess.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMOrcShared.a  lib/libswiftMigrator.a  lib/libswiftPrintAsClang.a  lib/libswiftThreading.a  lib/libSourceKitCore.a  lib/libswiftFrontend.a  lib/libswiftAPIDigester.a  lib/libswiftConstExtract.a  lib/libswiftLocalization.a  lib/libswiftIRGen.a  lib/libswiftSILGen.a  lib/libswiftSILOptimizer.a  lib/libswiftLLVMPasses.a  lib/libswiftSymbolGraphGen.a  lib/libswiftRefactoring.a  lib/libswiftIndex.a  lib/libswiftIDE.a  lib/libswiftDriver.a  lib/libswiftSIL.a  lib/libswiftSema.a  lib/libswiftSerialization.a  lib/libswiftSIL.a  lib/libswiftSema.a  lib/libswiftSerialization.a  lib/libswiftClangImporter.a  lib/libswiftParse.a  lib/libswiftOption.a  lib/libswiftIDEUtilsBridging.a  lib/libswiftASTGen.a  lib/swift/host/compiler/lib_CompilerSwiftCompilerPluginMessageHandling.so  lib/swift/host/compiler/lib_CompilerSwiftSyntaxMacroExpansion.so  lib/swift/host/compiler/lib_CompilerSwiftOperators.so  lib/swift/host/compiler/lib_CompilerSwiftSyntaxMacros.so  lib/swift/host/compiler/lib_CompilerSwiftSyntaxBuilder.so  lib/swift/host/compiler/lib_CompilerSwiftParserDiagnostics.so  lib/swift/host/compiler/lib_CompilerSwiftBasicFormat.so  lib/swift/host/compiler/lib_CompilerSwiftIDEUtils.so  lib/swift/host/compiler/lib_CompilerSwiftParser.so  lib/swift/host/compiler/lib_CompilerSwiftDiagnostics.so  lib/lib_CompilerRegexParser.a  lib/swift/host/compiler/lib_CompilerSwiftSyntax.so  lib/libswiftAST.a  lib/libswiftMarkup.a  /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangDependencyScanning.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMX86CodeGen.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMX86AsmParser.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMX86Desc.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMX86Disassembler.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMX86Info.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMARMCodeGen.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMARMAsmParser.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMARMDisassembler.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMARMDesc.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMARMInfo.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMARMUtils.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAArch64CodeGen.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMCFGuard.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAArch64AsmParser.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAArch64Disassembler.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAArch64Desc.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAArch64Info.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAArch64Utils.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMPowerPCCodeGen.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMPowerPCAsmParser.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMPowerPCDesc.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMPowerPCDisassembler.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMPowerPCInfo.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMSystemZCodeGen.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMSystemZAsmParser.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMSystemZDisassembler.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMSystemZDesc.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMSystemZInfo.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMMipsCodeGen.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMMipsAsmParser.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMMipsDesc.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMMipsDisassembler.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMMipsInfo.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMRISCVCodeGen.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMGlobalISel.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMRISCVAsmParser.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMRISCVDisassembler.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMRISCVDesc.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMRISCVInfo.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMWebAssemblyCodeGen.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMWebAssemblyAsmParser.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMWebAssemblyDisassembler.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMWebAssemblyUtils.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMWebAssemblyDesc.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMWebAssemblyInfo.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAVRCodeGen.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAsmPrinter.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMSelectionDAG.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAVRAsmParser.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAVRDesc.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAVRDisassembler.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMMCDisassembler.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAVRInfo.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangTooling.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangToolingRefactor.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangToolingRefactoring.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangToolingSyntax.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangFrontendTool.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangExtractAPI.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangARCMigrate.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangStaticAnalyzerFrontend.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangStaticAnalyzerCheckers.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangStaticAnalyzerCore.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangCrossTU.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangIndex.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangFormat.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangToolingInclusions.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangToolingCore.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangCodeGen.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMCoverage.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMLTO.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMExtensions.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMPasses.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMCodeGen.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMObjCARCOpts.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMCodeGenTypes.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMTarget.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMCoroutines.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMipo.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMBitWriter.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMInstrumentation.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMLinker.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMVectorize.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMIRPrinter.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangRewriteFrontend.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangFrontend.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangDriver.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMWindowsDriver.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMOption.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangParse.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMRemoteCachingService.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMRemoteNullService.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangCAS.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMMCCAS.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangSerialization.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangSema.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangAnalysis.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangASTMatchers.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMFrontendHLSL.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangSupport.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangEdit.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangAST.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMFrontendOpenMP.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMScalarOpts.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAggressiveInstCombine.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMInstCombine.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMTransformUtils.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAnalysis.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMProfileData.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMSymbolize.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMDebugInfoDWARF.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMDebugInfoPDB.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMObject.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMMCParser.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMMC.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMCASUtil.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMCAS.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMIRReader.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMAsmParser.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMTextAPI.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMDebugInfoCodeView.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMDebugInfoMSF.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMDebugInfoBTF.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangAPINotes.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMBitReader.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMCore.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMBinaryFormat.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMRemarks.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMBitstreamReader.a  lib/libsourcekitdAPI.a  lib/libSourceKitSupport.a  lib/libswiftBasic.a  lib/libswiftDemangling.a  -lpthread  /usr/lib64/libuuid.so  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangRewrite.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangLex.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libclangBasic.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMTargetParser.a  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMSupport.a  -ldl  -lrt  -lm  /usr/lib64/libz.so  /usr/lib64/libzstd.so  /usr/lib64/libtinfo.so  /path/to/swift/build/buildbot_linux/llvm-linux-x86_64/lib/libLLVMDemangle.a  -ldispatch  -lBlocksRuntime  lib/libswiftCompilerModules.a && :
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(blocks.c.o): requires unsupported dynamic reloc 11; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(buffer.c.o): requires unsupported dynamic reloc 11; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(cmark.c.o): requires dynamic R_X86_64_32 reloc which may overflow at runtime; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(cmark_ctype.c.o): requires unsupported dynamic reloc 11; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(footnotes.c.o): requires dynamic R_X86_64_32 reloc which may overflow at runtime; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(houdini_html_u.c.o): requires dynamic R_X86_64_32 reloc which may overflow at runtime; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(html.c.o): requires unsupported dynamic reloc 11; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(inlines.c.o): requires dynamic R_X86_64_32 reloc which may overflow at runtime; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(iterator.c.o): requires unsupported dynamic reloc 11; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(map.c.o): requires unsupported dynamic reloc 11; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(node.c.o): requires dynamic R_X86_64_32 reloc which may overflow at runtime; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(references.c.o): requires unsupported dynamic reloc 11; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(scanners.c.o): requires unsupported dynamic reloc 11; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(utf8.c.o): requires unsupported dynamic reloc 11; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(houdini_href_e.c.o): requires dynamic R_X86_64_32 reloc which may overflow at runtime; recompile with -fPIC
/usr/bin/ld.gold: error: /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src/libcmark-gfm.a(houdini_html_e.c.o): requires unsupported dynamic reloc 11; recompile with -fPIC

This error occurs because libcmark-gfm is not compiled for position-independent code.

Interestingly, the upstream cmark project unconditionally applies POSITION_INDEPENDENT_CODE in this PR commonmark/cmark#513, but Swift's fork https://github.com/swiftlang/swift-cmark/blob/2c47322cb32cbed555f13bf5cbfaa488cc30a785/src/CMakeLists.txt lacks this change.

To avoid linking errors, it would be beneficial if Swift's fork of cmark also adopts the same change, as demonstrated in this patch: tachoknight/swift-lang-packaging-fedora@c12a145

[QuietMisdreavus]

It's worth noting that swift-cmark is a fork of cmark-gfm now, and it doesn't seem to have picked up the PIC change since it hasn't synced from upstream CommonMark in some time. We should be able to take this change in swift-cmark, though.

[bc-lee]

I checked more about why the linker error occurred on my system but not in Swift's CI. To investigate, I downloaded the swift-DEVELOPMENT-SNAPSHOT-2024-07-11-a-ubi9 toolchain and compared the resulting objects and compiler invocations with those from my system's clang.

My system's clang produces non-PIC objects, while Swift's clang produces PIC objects.

Fedora's readelf result

$ readelf -a buildbot_linux/cmark-linux-x86_64/src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o  | grep -C 5 "Relocation section"

There are no program headers in this file.

There is no dynamic section in this file.

Relocation section '.rela.text' at offset 0x380 contains 5 entries:
  Offset          Info           Type           Sym. Value    Sym. Name + Addend
000000000008  00040000000b R_X86_64_32S      0000000000000000 .rodata + 0
000000000028  00040000000b R_X86_64_32S      0000000000000000 .rodata + 0
000000000047  00040000000b R_X86_64_32S      0000000000000000 .rodata + 0
000000000068  00040000000b R_X86_64_32S      0000000000000000 .rodata + 0
000000000088  00040000000b R_X86_64_32S      0000000000000000 .rodata + 0

Relocation section '.rela.eh_frame' at offset 0x3f8 contains 5 entries:
  Offset          Info           Type           Sym. Value    Sym. Name + Addend
000000000020  000200000002 R_X86_64_PC32     0000000000000000 .text + 0
000000000034  000200000002 R_X86_64_PC32     0000000000000000 .text + 20
000000000048  000200000002 R_X86_64_PC32     0000000000000000 .text + 40
00000000005c  000200000002 R_X86_64_PC32     0000000000000000 .text + 60

Clang from swift snapshot's readelf result

$ readelf -a buildbot_linux/cmark-linux-x86_64/src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o  | grep -C 5 "Relocation section"

There are no program headers in this file.

There is no dynamic section in this file.

Relocation section '.rela.text' at offset 0x3c0 contains 5 entries:
  Offset          Info           Type           Sym. Value    Sym. Name + Addend
000000000007  000400000002 R_X86_64_PC32     0000000000000000 .rodata - 4
000000000027  000400000002 R_X86_64_PC32     0000000000000000 .rodata - 4
000000000047  000400000002 R_X86_64_PC32     0000000000000000 .rodata - 4
000000000067  000400000002 R_X86_64_PC32     0000000000000000 .rodata - 4
000000000087  000400000002 R_X86_64_PC32     0000000000000000 .rodata - 4

Relocation section '.rela.eh_frame' at offset 0x438 contains 5 entries:
  Offset          Info           Type           Sym. Value    Sym. Name + Addend
000000000020  000200000002 R_X86_64_PC32     0000000000000000 .text + 0
000000000034  000200000002 R_X86_64_PC32     0000000000000000 .text + 20
000000000048  000200000002 R_X86_64_PC32     0000000000000000 .text + 40
00000000005c  000200000002 R_X86_64_PC32     0000000000000000 .text + 60

As you can see, Swift's clang produces PIC objects, while Fedora's clang does not. This raises the question: why does Swift's clang produce PIC objects, while Fedora's clang does not?

I checked the detailed logs of each compiler's invocation and found the difference.

Fedora's clang invocation

$ /usr/bin/clang --target=x86_64-unknown-linux-gnu -DCMARK_GFM_STATIC_DEFINE -DCMARK_THREADING -I/path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src -I/path/to/swift/cmark/src -I/path/to/swift/cmark/src/include -I/path/to/swift/cmark/extensions/include -Wno-unknown-warning-option -Werror=unguarded-availability-new -fno-stack-protector -O3 -DNDEBUG -std=c99 -fvisibility=hidden -Wall -Wextra -Wno-unused-parameter -pedantic -MD -MT src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o -MF src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o.d -o src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o -c /path/to/swift/cmark/src/cmark_ctype.c -v
clang version 18.1.6 (Fedora 18.1.6-3.fc40)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
System configuration file directory: /etc/clang/
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-redhat-linux/14
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-redhat-linux/14
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
 (in-process)
 "/usr/bin/clang-18" -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name cmark_ctype.c -mrelocation-model static -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fdebug-compilation-dir=/path/to/swift/build/buildbot_linux/cmark-linux-x86_64 -v -fcoverage-compilation-dir=/path/to/swift/build/buildbot_linux/cmark-linux-x86_64 -resource-dir /usr/bin/../lib/clang/18 -dependency-file src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o.d -MT src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o -sys-header-deps -D CMARK_GFM_STATIC_DEFINE -D CMARK_THREADING -I /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src -I /path/to/swift/cmark/src -I /path/to/swift/cmark/src/include -I /path/to/swift/cmark/extensions/include -D NDEBUG -internal-isystem /usr/bin/../lib/clang/18/include -internal-isystem /usr/local/include -internal-isystem /usr/bin/../lib/gcc/x86_64-redhat-linux/14/../../../../x86_64-redhat-linux/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -O3 -Wno-unknown-warning-option -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -pedantic -std=c99 -ferror-limit 19 -fvisibility=hidden -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fcolor-diagnostics -vectorize-loops -vectorize-slp -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o -x c /path/to/swift/cmark/src/cmark_ctype.c
clang -cc1 version 18.1.6 based upon LLVM 18.1.6 default target x86_64-redhat-linux-gnu
ignoring nonexistent directory "/usr/bin/../lib/gcc/x86_64-redhat-linux/14/../../../../x86_64-redhat-linux/include"
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
 /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src
 /path/to/swift/cmark/src
 /path/to/swift/cmark/src/include
 /path/to/swift/cmark/extensions/include
 /usr/bin/../lib/clang/18/include
 /usr/local/include
 /usr/include
End of search list.

Clang from Swift snapshot's clang invocation

$ /path/to-toolchain/swift-DEVELOPMENT-SNAPSHOT-2024-07-11-a-ubi9/usr/bin/clang --target=x86_64-unknown-linux-gnu -DCMARK_GFM_STATIC_DEFINE -DCMARK_THREADING -I/path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src -I/path/to/swift/cmark/src -I/path/to/swift/cmark/src/include -I/path/to/swift/cmark/extensions/include -Wno-unknown-warning-option -Werror=unguarded-availability-new -fno-stack-protector -O3 -DNDEBUG -std=c99 -fvisibility=hidden -Wall -Wextra -Wno-unused-parameter -pedantic -MD -MT src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o -MF src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o.d -o src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o -c /path/to/swift/cmark/src/cmark_ctype.c -v
clang version 17.0.0 (https://github.com/swiftlang/llvm-project.git 0ad8ad0245d47b47e10e286c291ef2821cdfb616)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /path/to-toolchain/swift-DEVELOPMENT-SNAPSHOT-2024-07-11-a-ubi9/usr/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/14
Selected GCC installation: /usr/lib/gcc/x86_64-redhat-linux/14
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
 (in-process)
 "/path/to-toolchain/swift-DEVELOPMENT-SNAPSHOT-2024-07-11-a-ubi9/usr/bin/clang-17" -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -disable-free -clear-ast-before-backend -main-file-name cmark_ctype.c -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -v -fcoverage-compilation-dir=/path/to/swift/build/buildbot_linux/cmark-linux-x86_64 -resource-dir /path/to-toolchain/swift-DEVELOPMENT-SNAPSHOT-2024-07-11-a-ubi9/usr/lib/clang/17 -dependency-file src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o.d -skip-unused-modulemap-deps -MT src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o -sys-header-deps -D CMARK_GFM_STATIC_DEFINE -D CMARK_THREADING -I /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src -I /path/to/swift/cmark/src -I /path/to/swift/cmark/src/include -I /path/to/swift/cmark/extensions/include -D NDEBUG -internal-isystem /path/to-toolchain/swift-DEVELOPMENT-SNAPSHOT-2024-07-11-a-ubi9/usr/lib/clang/17/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-redhat-linux/14/../../../../x86_64-redhat-linux/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -O3 -Wno-unknown-warning-option -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -pedantic -std=c99 -fdebug-compilation-dir=/path/to/swift/build/buildbot_linux/cmark-linux-x86_64 -ferror-limit 19 -fvisibility=hidden -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o src/CMakeFiles/libcmark-gfm.dir/cmark_ctype.c.o -x c /path/to/swift/cmark/src/cmark_ctype.c
clang -cc1 version 17.0.0 based upon LLVM 17.0.0 default target x86_64-unknown-linux-gnu
ignoring nonexistent directory "/usr/lib/gcc/x86_64-redhat-linux/14/../../../../x86_64-redhat-linux/include"
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
 /path/to/swift/build/buildbot_linux/cmark-linux-x86_64/src
 /path/to/swift/cmark/src
 /path/to/swift/cmark/src/include
 /path/to/swift/cmark/extensions/include
 /path/to-toolchain/swift-DEVELOPMENT-SNAPSHOT-2024-07-11-a-ubi9/usr/lib/clang/17/include
 /usr/local/include
 /usr/include
End of search list.

While both compilers are invoked with the same flags, Swift's clang uses -mrelocation-model pic while Fedora's clang uses -mrelocation-model static. This is why Swift's clang produces PIC objects while Fedora's clang does not.

In conclusion, since Swift's clang produces PIC objects implicitly, I suggest adding CMake flags to make PIC objects explicitly and unconditionally. This would make the build more consistent across different systems and compilers.

[QuietMisdreavus]

@bc-lee Thanks so much for your investigation! I'm fairly unfamiliar with the fine dynamics of ELF sections and PIC, but it seems like the PR you made to swift-cmark is a good step. I'll go ahead and merge it in.