Android: Switch to native ELF TLS & latest LTS NDK, and enable shared druntime/Phobos

.github/actions/3-build-cross/action.yml

@@ -14,10 +14,10 @@ inputs:
     default: false
   android_ndk_version:
     required: false
-    default: r21e
+    default: r26d
   android_api_level:
     required: false
-    default: 21
+    default: 29
 runs:
   using: composite
   steps:
@@ -92,32 +92,30 @@ runs:
         cd ..
         version='${{ inputs.android_ndk_version }}'
         curl -fL --retry 3 --max-time 300 -o android-ndk.zip \
-          https://dl.google.com/android/repository/android-ndk-$version-linux-x86_64.zip
+          https://dl.google.com/android/repository/android-ndk-$version-linux.zip
         unzip android-ndk.zip >/dev/null
         mv "android-ndk-$version" android-ndk
         rm android-ndk.zip
 
-        # The NDK toolchain file enforces `-g` as base C[XX] flag - remove it to
-        # *significantly* reduce executable sizes
-        toolchainFile="$PWD/android-ndk/build/cmake/android.toolchain.cmake"
-        sed -i 's|^  -g$||' "$toolchainFile"
-
         arch='${{ inputs.arch }}'
         apiLevel='${{ inputs.android_api_level }}'
         cmakeFlags="-DTARGET_SYSTEM='Android;Linux;UNIX'"
         if [[ "$arch" == armv7a ]]; then
           triple="$arch-linux-androideabi$apiLevel"
           cmakeFlags+=' -DANDROID_ABI=armeabi-v7a'
         elif [[ "$arch" == aarch64 ]]; then
+          # FIXME: as of NDK rc26d, libc.a has __tls_get_addr, but libc.so only since API level 30 (Android v11)
+          apiLevel=30
           triple="$arch-linux-android$apiLevel"
           cmakeFlags+=' -DANDROID_ABI=arm64-v8a'
         fi
         cmakeFlags+=" -DANDROID_NATIVE_API_LEVEL=$apiLevel"
         cmakeFlags+=" -DANDROID_STL=c++_static"
-        cmakeFlags+=" -DCMAKE_TOOLCHAIN_FILE=$toolchainFile"
-        cmakeFlags+=" -DLDC_LINK_MANUALLY=ON -DD_LINKER_ARGS='-fuse-ld=bfd;-L$PWD/build-cross-libs/lib;-lphobos2-ldc;-ldruntime-ldc'"
+        cmakeFlags+=" -DCMAKE_TOOLCHAIN_FILE=$PWD/android-ndk/build/cmake/android.toolchain.cmake"
+        cmakeFlags+=" -DANDROID_USE_LEGACY_TOOLCHAIN_FILE=OFF"
+        cmakeFlags+=" -DLDC_LINK_MANUALLY=ON -DD_LINKER_ARGS='-L$PWD/build-cross-libs/lib;-lphobos2-ldc;-ldruntime-ldc'"
 
-        echo "DFLAGS=-mtriple=$triple -fvisibility=hidden -L-L$PWD/build-cross-libs/lib -gcc=$PWD/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/$triple-clang" >> $GITHUB_ENV
+        echo "DFLAGS=-mtriple=$triple -L-L$PWD/build-cross-libs/lib -gcc=$PWD/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/$triple-clang" >> $GITHUB_ENV
         echo "CROSS_TRIPLE=$triple" >> $GITHUB_ENV
         echo "CROSS_CMAKE_FLAGS=$cmakeFlags" >> $GITHUB_ENV
 

.github/actions/3-build-cross/android-llvm-config.in

@@ -53,25 +53,25 @@ LIBFILE="${prefix}/lib/libLLVM-$version.so"
 components="aarch64 aarch64asmparser aarch64codegen aarch64desc aarch64disassembler aarch64info aarch64utils \
 aggressiveinstcombine all all-targets analysis arm armasmparser armcodegen armdesc armdisassembler arminfo armutils \
 asmparser asmprinter binaryformat bitreader bitstreamreader bitwriter cfguard codegen codegentypes core coroutines coverage \
-debuginfobtf debuginfocodeview debuginfodwarf debuginfogsym debuginfologicalview debuginfomsf debuginfopdb demangle dlltooldriver dwarflinker dwarflinkerparallel dwp \
-engine executionengine extensions filecheck frontendhlsl frontendopenacc frontendopenmp fuzzercli fuzzmutate globalisel instcombine \
+debuginfobtf debuginfocodeview debuginfodwarf debuginfogsym debuginfologicalview debuginfomsf debuginfopdb demangle dlltooldriver dwarflinker dwarflinkerclassic dwarflinkerparallel dwp \
+engine executionengine extensions filecheck frontenddriver frontendhlsl frontendoffloading frontendopenacc frontendopenmp fuzzercli fuzzmutate globalisel hipstdpar instcombine \
 instrumentation interfacestub interpreter ipo irprinter irreader jitlink libdriver lineeditor linker lto mc mca mcdisassembler \
-mcjit mcparser mirparser native nativecodegen objcarcopts objcopy object objectyaml option orcjit orcshared orctargetprocess \
+mcjit mcparser mirparser native nativecodegen objcarcopts objcopy object objectyaml option orcdebugging orcjit orcshared orctargetprocess \
 passes profiledata remarks runtimedyld scalaropts selectiondag spirv spirvcodegen spirvdesc spirvinfo support symbolize tablegen target targetparser textapi \
-transformutils vectorize webassembly webassemblyasmparser webassemblycodegen webassemblydesc webassemblydisassembler \
+textapibinaryreader transformutils vectorize webassembly webassemblyasmparser webassemblycodegen webassemblydesc webassemblydisassembler \
 webassemblyinfo webassemblyutils windowsdriver windowsmanifest x86 x86asmparser x86codegen x86desc x86disassembler x86info \
 x86targetmca xray"
-static_libs="-lLLVMWindowsManifest -lLLVMXRay -lLLVMLibDriver -lLLVMDlltoolDriver -lLLVMCoverage -lLLVMLineEditor \
+static_libs="-lLLVMWindowsManifest -lLLVMXRay -lLLVMLibDriver -lLLVMDlltoolDriver -lLLVMTextAPIBinaryReader -lLLVMCoverage -lLLVMLineEditor \
 -lLLVMSPIRVCodeGen -lLLVMSPIRVDesc -lLLVMSPIRVInfo \
 -lLLVMX86TargetMCA -lLLVMX86Disassembler -lLLVMX86AsmParser -lLLVMX86CodeGen -lLLVMX86Desc -lLLVMX86Info -lLLVMWebAssemblyDisassembler \
 -lLLVMWebAssemblyAsmParser -lLLVMWebAssemblyCodeGen -lLLVMWebAssemblyUtils -lLLVMWebAssemblyDesc -lLLVMWebAssemblyInfo -lLLVMARMDisassembler \
 -lLLVMARMAsmParser -lLLVMARMCodeGen -lLLVMARMDesc -lLLVMARMUtils -lLLVMARMInfo -lLLVMAArch64Disassembler \
--lLLVMAArch64AsmParser -lLLVMAArch64CodeGen -lLLVMAArch64Desc -lLLVMAArch64Utils -lLLVMAArch64Info -lLLVMOrcJIT \
+-lLLVMAArch64AsmParser -lLLVMAArch64CodeGen -lLLVMAArch64Desc -lLLVMAArch64Utils -lLLVMAArch64Info -lLLVMOrcDebugging -lLLVMOrcJIT \
 -lLLVMWindowsDriver -lLLVMMCJIT -lLLVMJITLink -lLLVMInterpreter -lLLVMExecutionEngine -lLLVMRuntimeDyld -lLLVMOrcTargetProcess -lLLVMOrcShared \
 -lLLVMDWP -lLLVMDebugInfoLogicalView -lLLVMDebugInfoGSYM -lLLVMOption -lLLVMObjectYAML -lLLVMObjCopy -lLLVMMCA \
--lLLVMMCDisassembler -lLLVMLTO -lLLVMPasses -lLLVMCFGuard -lLLVMCoroutines -lLLVMipo \
--lLLVMVectorize -lLLVMLinker -lLLVMInstrumentation -lLLVMFrontendOpenMP -lLLVMFrontendOpenACC -lLLVMFrontendHLSL -lLLVMExtensions \
--lLLVMDWARFLinkerParallel -lLLVMDWARFLinker -lLLVMGlobalISel -lLLVMMIRParser -lLLVMAsmPrinter -lLLVMSelectionDAG \
+-lLLVMMCDisassembler -lLLVMLTO -lLLVMPasses -lLLVMHipStdPar -lLLVMCFGuard -lLLVMCoroutines -lLLVMipo \
+-lLLVMVectorize -lLLVMLinker -lLLVMInstrumentation -lLLVMFrontendOpenMP -lLLVMFrontendOffloading -lLLVMFrontendOpenACC -lLLVMFrontendHLSL -lLLVMFrontendDriver -lLLVMExtensions \
+-lLLVMDWARFLinkerParallel -lLLVMDWARFLinkerClassic -lLLVMDWARFLinker -lLLVMGlobalISel -lLLVMMIRParser -lLLVMAsmPrinter -lLLVMSelectionDAG \
 -lLLVMCodeGen -lLLVMTarget -lLLVMObjCARCOpts -lLLVMCodeGenTypes -lLLVMIRPrinter -lLLVMInterfaceStub -lLLVMFileCheck -lLLVMFuzzMutate \
 -lLLVMScalarOpts -lLLVMInstCombine -lLLVMAggressiveInstCombine -lLLVMTransformUtils -lLLVMBitWriter -lLLVMAnalysis \
 -lLLVMProfileData -lLLVMSymbolize -lLLVMDebugInfoBTF -lLLVMDebugInfoPDB -lLLVMDebugInfoMSF -lLLVMDebugInfoDWARF -lLLVMObject -lLLVMTextAPI -lLLVMMCParser -lLLVMIRReader -lLLVMAsmParser -lLLVMMC -lLLVMDebugInfoCodeView \

.github/actions/5a-android-x86/action.yml

@@ -23,10 +23,10 @@ runs:
         # use bootstrap-ldc, which is guaranteed to be native
         bootstrap-ldc/bin/ldc-build-runtime --ninja \
           --buildDir="build-libs-$arch" \
-          --dFlags="-mtriple=$triple;-fvisibility=hidden" \
+          --dFlags="-mtriple=$triple" \
           --ldcSrcDir="$PWD/ldc" \
           "${flags[@]}" \
           ANDROID_ABI="$abi" # override the one in CROSS_CMAKE_FLAGS
 
         mkdir "installed/lib-$arch"
-        cp "build-libs-$arch"/lib/*.a "installed/lib-$arch/"
+        cp "build-libs-$arch"/lib/* "installed/lib-$arch/"

.github/workflows/main.yml

@@ -171,6 +171,7 @@ jobs:
               -DD_COMPILER_FLAGS="-O -flto=full -defaultlib=phobos2-ldc-lto,druntime-ldc-lto -L-exported_symbol '-L__*' -L-w"
               -DEXTRA_CXXFLAGS=-flto=full
             with_pgo: true
+            llvm_version: 17.0.6 # TODO
 
           - job_name: Android armv7a
             host_os: ubuntu-20.04
@@ -192,7 +193,6 @@ jobs:
     timeout-minutes: 60
     env:
       MACOSX_DEPLOYMENT_TARGET: 11.0
-      LLVM_VERSION: 17.0.6 # TODO
     steps:
       - uses: actions/checkout@v4
         with:
@@ -202,7 +202,7 @@ jobs:
         uses: ./.github/actions/1-setup
         with:
           clang_version: ${{ env.CLANG_VERSION }}
-          llvm_version: ${{ env.LLVM_VERSION }}
+          llvm_version: ${{ matrix.llvm_version || env.LLVM_VERSION }}
           arch: x86_64
       - name: Build bootstrap LDC
         uses: ./.github/actions/2-build-bootstrap
@@ -218,7 +218,7 @@ jobs:
         with:
           arch: ${{ matrix.arch }}
           os: ${{ matrix.os }}
-          llvm_version: ${{ env.LLVM_VERSION }}
+          llvm_version: ${{ matrix.llvm_version || env.LLVM_VERSION }}
           cmake_flags: ${{ matrix.extra_cmake_flags }}
           with_pgo: ${{ matrix.with_pgo }}
 

CHANGELOG.md

@@ -2,12 +2,14 @@
 
 #### Big news
 - Frontend, druntime and Phobos are at version [2.108.0+](https://dlang.org/changelog/2.108.0.html). (#4591, #4615, #4619)
-- Support for [LLVM 18](https://releases.llvm.org/18.1.0/docs/ReleaseNotes.html). The prebuilt packages use v18.1.3 (except for Android and macOS arm64). (#4599, #4605, #4607, #4604, #4622)
+- Support for [LLVM 18](https://releases.llvm.org/18.1.0/docs/ReleaseNotes.html). The prebuilt packages use v18.1.3 (except for macOS arm64). (#4599, #4605, #4607, #4604, #4622)
+- Android: Switch to native ELF TLS, supported since API level 29 (Android v10), dropping our former custom TLS emulation (requiring a modified LLVM and a legacy ld.bfd linker). The prebuilt packages themselves require Android v10+ (armv7a) / v11+ (aarch64) too, and are built with NDK r26d. Shared druntime and Phobos libraries are now available (`-link-defaultlib-shared`), as on regular Linux. (#4618)
 
 #### Platform support
 - Supports LLVM 11 - 18.
 
 #### Bug fixes
+- Android: Support the lld linker. (#3918)
 
 # LDC 1.37.0 (2024-03-03)
 

driver/linker-gcc.cpp

@@ -621,14 +621,6 @@ void ArgsBuilder::build(llvm::StringRef outputPath,
 void ArgsBuilder::addLinker() {
   llvm::StringRef linker = opts::linker;
 
-  // Default to ld.bfd for Android (placing .tdata and .tbss sections adjacent
-  // to each other as required by druntime's rt.sections_android, contrary to
-  // gold and lld as of Android NDK r21d).
-  if (global.params.targetTriple->getEnvironment() == llvm::Triple::Android &&
-      opts::linker.getNumOccurrences() == 0) {
-    linker = "bfd";
-  }
-
   if (!linker.empty())
     args.push_back(("-fuse-ld=" + linker).str());
 }

driver/main.d

@@ -59,18 +59,3 @@ version (Windows)
         SetConsoleOutputCP(originalOutputCP);
     }
 }
-
-// TLS bracketing symbols required for our custom TLS emulation on Android
-// as we don't have a D main() function for LDC and LDMD.
-version (Android)
-{
-    import ldc.attributes;
-
-    extern(C) __gshared
-    {
-        @section(".tdata")
-        int _tlsstart = 0;
-        @section(".tcommon")
-        int _tlsend = 0;
-    }
-}

driver/targetmachine.cpp

@@ -639,12 +639,14 @@ createTargetMachine(const std::string targetTriple, const std::string arch,
     targetOptions.DataSections = true;
   }
 
-  // On Android, we depend on a custom TLS emulation scheme implemented in our
-  // LLVM fork. LLVM 7+ enables regular emutls by default; prevent that.
+  // On Android, enforce native ELF TLS (supported since API level 29 = Android
+  // v10), as required by druntime. (Some older LLVM versions might default to
+  // EmuTLS).
   if (triple.getEnvironment() == llvm::Triple::Android) {
     targetOptions.EmulatedTLS = false;
 #if LDC_LLVM_VER < 1700
-    // Removed in this commit: https://github.com/llvm/llvm-project/commit/0d333bf0e3aa37e2e6ae211e3aa80631c3e01b85
+    // Removed in this commit:
+    // https://github.com/llvm/llvm-project/commit/0d333bf0e3aa37e2e6ae211e3aa80631c3e01b85
     targetOptions.ExplicitEmulatedTLS = true;
 #endif
   }

runtime/CMakeLists.txt

@@ -89,8 +89,7 @@ else()
 endif()
 
 set(SHARED_LIBS_SUPPORTED OFF)
-if("${TARGET_SYSTEM}" MATCHES "Windows|Linux|FreeBSD|DragonFly|APPLE"
-   AND (NOT "${TARGET_SYSTEM}" MATCHES "Android"))
+if("${TARGET_SYSTEM}" MATCHES "Windows|Linux|FreeBSD|DragonFly|APPLE")
     set(SHARED_LIBS_SUPPORTED ON)
 endif()
 

runtime/druntime/src/core/sys/posix/dlfcn.d

@@ -372,12 +372,20 @@ else version (Solaris)
 }
 else version (CRuntime_Bionic)
 {
-    enum
+    enum RTLD_LOCAL    = 0;
+    enum RTLD_LAZY     = 0x00001;
+    enum RTLD_NOLOAD   = 0x00004;
+    enum RTLD_NODELETE = 0x01000;
+
+    version (D_LP64)
+    {
+        enum RTLD_NOW      = 0x00002;
+        enum RTLD_GLOBAL   = 0x00100;
+    }
+    else // NDK: 'LP32 is broken for historical reasons'
     {
-        RTLD_NOW    = 0,
-        RTLD_LAZY   = 1,
-        RTLD_LOCAL  = 0,
-        RTLD_GLOBAL = 2
+        enum RTLD_NOW      = 0;
+        enum RTLD_GLOBAL   = 0x00002;
     }
 
     int          dladdr(const scope void*, Dl_info*);

runtime/druntime/src/rt/sections.d

@@ -64,7 +64,7 @@ else version (CRuntime_Microsoft)
         public import rt.sections_win64;
 }
 else version (CRuntime_Bionic)
-    public import rt.sections_android;
+    public import rt.sections_elf_shared;
 else version (CRuntime_UClibc)
     public import rt.sections_elf_shared;
 else

runtime/druntime/src/rt/sections_android.d

@@ -10,6 +10,8 @@
 
 module rt.sections_android;
 
+version (LDC) { /* implemented in rt.sections_elf_shared */ } else:
+
 version (CRuntime_Bionic):
 
 // debug = PRINTF;

runtime/druntime/src/rt/sections_elf_shared.d

@@ -24,6 +24,7 @@ else version (CRuntime_Musl) enum SharedELF = true;
 else version (FreeBSD) enum SharedELF = true;
 else version (NetBSD) enum SharedELF = true;
 else version (DragonFlyBSD) enum SharedELF = true;
+else version (CRuntime_Bionic) enum SharedELF = true;
 else version (CRuntime_UClibc) enum SharedELF = true;
 else enum SharedELF = false;
 
@@ -1171,6 +1172,8 @@ else
 
 version (LDC)
 {
+    version (Android) version (X86) version = Android_X86;
+
     version (PPC)
     {
         extern(C) void* __tls_get_addr_opt(tls_index* ti) nothrow @nogc;
@@ -1181,6 +1184,11 @@ version (LDC)
         extern(C) void* __tls_get_addr_opt(tls_index* ti) nothrow @nogc;
         alias __tls_get_addr = __tls_get_addr_opt;
     }
+    else version (Android_X86) // extra underscore
+    {
+        extern(C) void* ___tls_get_addr(tls_index* ti) nothrow @nogc;
+        alias __tls_get_addr = ___tls_get_addr;
+    }
     else
         extern(C) void* __tls_get_addr(tls_index* ti) nothrow @nogc;
 }