CI: Add native Windows arm64 job/package

.github/actions/1-setup/action.yml

@@ -23,7 +23,7 @@ runs:
 
         packages=( \
           git-core cmake g++ \
-          libcurl4 libxml2-dev libzstd-dev \
+          libcurl4 libzstd-dev \
           curl gdb p7zip-full tzdata unzip zip python3-pip \
         )
         if [[ $arch == x86_64 ]]; then
@@ -37,30 +37,34 @@ runs:
         # Make sure to link libzstd statically
         sudo rm /usr/lib/$arch-linux-gnu/libzstd.so
 
-    - name: 'Linux: Install clang 19 from apt.llvm.org'
+    - name: 'Linux: Install clang 20 from apt.llvm.org'
       if: runner.os == 'Linux'
       shell: bash
       run: |
         set -eux
         cd ..
         curl -fL --retry 3 --max-time 30 -O https://apt.llvm.org/llvm.sh
-        sudo bash llvm.sh 19
+        sudo bash llvm.sh 20
         for tool in clang clang++ ld.lld; do
-          sudo ln -sf $tool-19 /usr/bin/$tool
+          sudo ln -sf $tool-20 /usr/bin/$tool
           $tool --version
         done
-    - name: 'macOS arm64: Install Homebrew clang 19' # see mimalloc comment in ../3-build-native/action.yml
+    - name: 'macOS arm64: Install Homebrew clang 20' # see mimalloc comment in ../3-build-native/action.yml
       if: runner.os == 'macOS' && inputs.arch == 'arm64'
       shell: bash
-      run: brew install llvm@19
-    - name: 'Windows: Install clang v19.1.3 from GitHub'
+      run: brew install llvm@20
+    - name: 'Windows: Install clang v20.1.3 from GitHub'
       if: runner.os == 'Windows'
       shell: bash
       run: |
         set -eux
         cd ..
+        suffix='win64'
+        if [[ '${{ inputs.arch }}' == arm64 ]]; then
+          suffix='woa64'
+        fi
         curl -fL --retry 3 --max-time 300 -o clang.exe \
-          https://github.com/llvm/llvm-project/releases/download/llvmorg-19.1.3/LLVM-19.1.3-win64.exe
+          https://github.com/llvm/llvm-project/releases/download/llvmorg-20.1.3/LLVM-20.1.3-$suffix.exe
         ./clang.exe //S # double-slash for bash
         rm clang.exe
         # C:\Program Files\LLVM\bin should already be in PATH
@@ -163,7 +167,9 @@ runs:
         cd ..
 
         url='https://curl.se/windows/latest.cgi?p=win64-mingw.zip'
-        if [[ '${{ inputs.arch }}' == x86 ]]; then
+        if [[ '${{ inputs.arch }}' == arm64 ]]; then
+          url='https://curl.se/windows/latest.cgi?p=win64a-mingw.zip'
+        elif [[ '${{ inputs.arch }}' == x86 ]]; then
           url='https://curl.se/windows/latest.cgi?p=win32-mingw.zip'
         fi
 

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

@@ -45,36 +45,36 @@ prefix=@LLVM_INSTALL_DIR@
 has_rtti=NO
 CPPFLAGS="-I${prefix}/include -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS"
 CFLAGS="${CPPFLAGS} ${CFLAGS}"
-CXXFLAGS="${CFLAGS} -std=c++17 -fno-exceptions -fno-unwind-tables -fno-asynchronous-unwind-tables"
+CXXFLAGS="${CFLAGS} -std=c++17 -fno-exceptions -funwind-tables"
 if [ "$has_rtti" != "YES" ]; then CXXFLAGS="$CXXFLAGS -fno-rtti"; fi
 LDFLAGS="-L${prefix}/lib"
 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 codegendata codegentypes core coroutines coverage \
+asmparser asmprinter binaryformat bitreader bitstreamreader bitwriter cfguard cgdata codegen codegentypes core coroutines coverage \
 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 \
+engine executionengine extensions filecheck frontendatomic 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 orcdebugging orcjit orcshared orctargetprocess \
-passes profiledata remarks runtimedyld sandboxir scalaropts selectiondag spirv spirvanalysis spirvcodegen spirvdesc spirvinfo support symbolize tablegen target targetparser textapi \
+passes profiledata remarks runtimedyld sandboxir scalaropts selectiondag spirv spirvanalysis spirvcodegen spirvdesc spirvinfo support symbolize tablegen target targetparser telemetry textapi \
 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 -lLLVMTextAPIBinaryReader -lLLVMCoverage -lLLVMLineEditor \
--lLLVMSandboxIR -lLLVMSPIRVCodeGen -lLLVMSPIRVDesc -lLLVMSPIRVInfo -lLLVMSPIRVAnalysis \
--lLLVMX86TargetMCA -lLLVMX86Disassembler -lLLVMX86AsmParser -lLLVMX86CodeGen -lLLVMX86Desc -lLLVMX86Info -lLLVMWebAssemblyDisassembler \
+static_libs="-lLLVMWindowsManifest -lLLVMXRay -lLLVMLibDriver -lLLVMDlltoolDriver -lLLVMTelemetry -lLLVMTextAPIBinaryReader -lLLVMCoverage -lLLVMLineEditor \
+-lLLVMX86TargetMCA -lLLVMX86Disassembler -lLLVMX86AsmParser -lLLVMX86CodeGen -lLLVMX86Desc -lLLVMX86Info \
+-lLLVMSPIRVCodeGen -lLLVMSPIRVDesc -lLLVMSPIRVInfo -lLLVMSPIRVAnalysis -lLLVMWebAssemblyDisassembler \
 -lLLVMWebAssemblyAsmParser -lLLVMWebAssemblyCodeGen -lLLVMWebAssemblyUtils -lLLVMWebAssemblyDesc -lLLVMWebAssemblyInfo -lLLVMARMDisassembler \
 -lLLVMARMAsmParser -lLLVMARMCodeGen -lLLVMARMDesc -lLLVMARMUtils -lLLVMARMInfo -lLLVMAArch64Disassembler \
 -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 -lLLVMHipStdPar -lLLVMCFGuard -lLLVMCoroutines -lLLVMipo \
--lLLVMVectorize -lLLVMLinker -lLLVMInstrumentation -lLLVMFrontendOpenMP -lLLVMFrontendOffloading -lLLVMFrontendOpenACC -lLLVMFrontendHLSL -lLLVMFrontendDriver -lLLVMExtensions \
--lLLVMDWARFLinkerParallel -lLLVMDWARFLinkerClassic -lLLVMDWARFLinker -lLLVMCodeGenData -lLLVMGlobalISel -lLLVMMIRParser -lLLVMAsmPrinter -lLLVMSelectionDAG \
--lLLVMCodeGen -lLLVMTarget -lLLVMObjCARCOpts -lLLVMCodeGenTypes -lLLVMIRPrinter -lLLVMInterfaceStub -lLLVMFileCheck -lLLVMFuzzMutate \
+-lLLVMVectorize -lLLVMSandboxIR -lLLVMLinker -lLLVMInstrumentation -lLLVMFrontendOpenMP -lLLVMFrontendOffloading -lLLVMFrontendOpenACC -lLLVMFrontendHLSL -lLLVMFrontendDriver -lLLVMFrontendAtomic -lLLVMExtensions \
+-lLLVMDWARFLinkerParallel -lLLVMDWARFLinkerClassic -lLLVMDWARFLinker -lLLVMGlobalISel -lLLVMMIRParser -lLLVMAsmPrinter -lLLVMSelectionDAG \
+-lLLVMCodeGen -lLLVMTarget -lLLVMObjCARCOpts -lLLVMCodeGenTypes -lLLVMCGData -lLLVMIRPrinter -lLLVMInterfaceStub -lLLVMFileCheck -lLLVMFuzzMutate \
 -lLLVMScalarOpts -lLLVMInstCombine -lLLVMAggressiveInstCombine -lLLVMTransformUtils -lLLVMBitWriter -lLLVMAnalysis \
--lLLVMProfileData -lLLVMSymbolize -lLLVMDebugInfoBTF -lLLVMDebugInfoPDB -lLLVMDebugInfoMSF -lLLVMDebugInfoDWARF -lLLVMObject -lLLVMTextAPI -lLLVMMCParser -lLLVMIRReader -lLLVMAsmParser -lLLVMMC -lLLVMDebugInfoCodeView \
+-lLLVMProfileData -lLLVMSymbolize -lLLVMDebugInfoBTF -lLLVMDebugInfoPDB -lLLVMDebugInfoMSF -lLLVMDebugInfoCodeView -lLLVMDebugInfoDWARF -lLLVMObject -lLLVMTextAPI -lLLVMMCParser -lLLVMIRReader -lLLVMAsmParser -lLLVMMC \
 -lLLVMBitReader -lLLVMFuzzerCLI -lLLVMCore -lLLVMRemarks -lLLVMBitstreamReader -lLLVMBinaryFormat -lLLVMTargetParser -lLLVMTableGen -lLLVMSupport \
 -lLLVMDemangle"
 shared_libs="-lLLVM-$version"

.github/actions/5-install/action.yml

@@ -66,6 +66,11 @@ runs:
 
         cp libcurl/ldc2/* installed/bin/
 
+        if [[ '${{ inputs.arch }}' == arm64 ]]; then
+          echo "No MinGW-based libraries available for arm64 yet."
+          exit 0
+        fi
+
         curl -fL --retry 3 --max-time 60 -o mingw-w64-libs.7z \
           https://github.com/ldc-developers/mingw-w64-libs/releases/download/v8.0.0/mingw-w64-libs-v8.0.0.7z
         mkdir mingw-w64-libs

.github/actions/merge-windows/action.yml

@@ -67,6 +67,7 @@ runs:
         set PATH=%CD%\ldc2-multilib\lib32;%PATH%
         ldc2-multilib\bin\ldc2 -link-defaultlib-shared -m32 -run hello.d || exit /b
 
+    # TODO
     # preliminary arm64 cross-compilation support
     - name: Install ninja v1.12.1
       uses: Ahajha/gha-setup-ninja@69595b0cf872acdad8ce599142fbdc88724b9a2b

.github/workflows/main.yml

@@ -14,7 +14,7 @@ concurrency:
   cancel-in-progress: true
 
 env:
-  LLVM_VERSION: 19.1.7
+  LLVM_VERSION: a905655f
 
 jobs:
   build-native:
@@ -85,8 +85,8 @@ jobs:
             os: macos-14
             arch: arm64
             extra_cmake_flags: >-
-              -DCMAKE_C_COMPILER=/opt/homebrew/opt/llvm@19/bin/clang
-              -DCMAKE_CXX_COMPILER=/opt/homebrew/opt/llvm@19/bin/clang++
+              -DCMAKE_C_COMPILER=/opt/homebrew/opt/llvm@20/bin/clang
+              -DCMAKE_CXX_COMPILER=/opt/homebrew/opt/llvm@20/bin/clang++
               -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
@@ -101,6 +101,17 @@ jobs:
               -DEXTRA_CXXFLAGS=-flto=full
             with_pgo: true
 
+          - job_name: Windows arm64
+            os: windows-11-arm
+            arch: arm64
+            base_cmake_flags: >-
+              -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreaded
+              -DD_COMPILER_FLAGS=-link-internally
+            #extra_cmake_flags: >-
+            #  "-DD_COMPILER_FLAGS=-O -flto=full -defaultlib=phobos2-ldc-lto,druntime-ldc-lto"
+            #  -DEXTRA_CXXFLAGS=-flto=full
+            #with_pgo: true
+
           - job_name: Windows x86
             os: windows-2025
             arch: x86

CMakeLists.txt

@@ -195,7 +195,10 @@ if(NOT MSVC_IDE)
 endif()
 
 if(MSVC)
-    if(CMAKE_SIZEOF_VOID_P EQUAL 8)
+    if($ENV{VSCMD_ARG_TGT_ARCH} STREQUAL "arm64")
+        message(STATUS "Let D host compiler output arm64 object files")
+        append("-mtriple=aarch64-windows-msvc" DFLAGS_BASE)
+    elseif(CMAKE_SIZEOF_VOID_P EQUAL 8)
         message(STATUS "Let D host compiler output 64-bit object files")
         append("-m64" DFLAGS_BASE)
     else()
@@ -300,7 +303,9 @@ endif()
 if(MSVC)
     separate_arguments(LLVM_LDFLAGS WINDOWS_COMMAND "${LLVM_LDFLAGS}")
     if(NOT MSVC_IDE) # apparently not needed for VS (and spaces in path are problematic)
-        if(CMAKE_SIZEOF_VOID_P EQUAL 8)
+        if($ENV{VSCMD_ARG_TGT_ARCH} STREQUAL "arm64")
+            list(APPEND LLVM_LDFLAGS "$ENV{VSINSTALLDIR}DIA SDK\\lib\\arm64\\diaguids.lib")
+        elseif(CMAKE_SIZEOF_VOID_P EQUAL 8)
             list(APPEND LLVM_LDFLAGS "$ENV{VSINSTALLDIR}DIA SDK\\lib\\amd64\\diaguids.lib")
         else()
             list(APPEND LLVM_LDFLAGS "$ENV{VSINSTALLDIR}DIA SDK\\lib\\diaguids.lib")
@@ -895,7 +900,9 @@ if (LDC_INSTALL_LLVM_RUNTIME_LIBS)
         copy_compilerrt_lib("libclang_rt.xray-profiling${compilerrt_suffix}.a" "libldc_rt.xray-profiling.a" FALSE)
     elseif(WIN32)
         set(compilerrt_arch_suffix "x86_64")
-        if(CMAKE_SIZEOF_VOID_P EQUAL 4)
+        if($ENV{VSCMD_ARG_TGT_ARCH} STREQUAL "arm64")
+            set(compilerrt_arch_suffix "aarch64")
+        elseif(CMAKE_SIZEOF_VOID_P EQUAL 4)
             set(compilerrt_arch_suffix "i386")
         endif()
         if(LDC_LLVM_VER LESS 2000)

dmd/main.d

@@ -442,8 +442,11 @@ else
     reconcileLinkRunLib(params, files.length, target.obj_ext);
     version(CRuntime_Microsoft)
     {
-        import dmd.root.longdouble;
-        initFPU();
+        version(AArch64) { /* no longdouble_soft support on arm64 host */ } else
+        {
+            import dmd.root.longdouble;
+            initFPU();
+        }
     }
     import dmd.root.ctfloat : CTFloat;
     CTFloat.initialize();

dmd/root/ctfloat.d

@@ -27,13 +27,17 @@ private
 {
     version(CRuntime_DigitalMars) __gshared extern (C) extern const(char)* __locale_decpoint;
 
-    version(CRuntime_Microsoft) extern (C++)
+    version(CRuntime_Microsoft)
     {
-        public import dmd.root.longdouble : longdouble_soft, ld_sprint;
+        version(AArch64) { /* 64-bit real_t */ } else
+        {
+            version = MSVC_X87;
+            import dmd.root.longdouble : longdouble_soft, ld_sprint;
 version (IN_LLVM) {} else
 {
-        import dmd.root.strtold;
+            import dmd.root.strtold;
 }
+        }
     }
 }
 
@@ -193,7 +197,7 @@ extern (C++) struct CTFloat
     // the implementation of longdouble for MSVC is a struct, so mangling
     //  doesn't match with the C++ header.
     // add a wrapper just for isSNaN as this is the only function called from C++
-    version(CRuntime_Microsoft) static if (is(real_t == real))
+    version(MSVC_X87) static if (is(real_t == real))
         pure @trusted
         static bool isSNaN(longdouble_soft ld)
         {
@@ -239,7 +243,7 @@ extern (C++) struct CTFloat
     @system
     static int sprint(char* str, size_t size, char fmt, real_t x)
     {
-        version(CRuntime_Microsoft)
+        version(MSVC_X87)
         {
             auto len = cast(int) ld_sprint(str, size, fmt, longdouble_soft(x));
         }

dmd/root/longdouble.d

@@ -13,7 +13,9 @@ module dmd.root.longdouble;
 
 version (CRuntime_Microsoft)
 {
-    static if (real.sizeof > 8)
+    version (AArch64)
+        alias longdouble = real; // 64-bit
+    else static if (real.sizeof > 8)
         alias longdouble = real;
     else
         alias longdouble = longdouble_soft;
@@ -24,6 +26,7 @@ else
 // longdouble_soft needed when building the backend with
 // Visual C or the frontend with LDC on Windows
 version (CRuntime_Microsoft):
+version (AArch64) { /* cannot use x87 inline asm on arm64 host */ } else:
 extern (C++):
 nothrow:
 @nogc:

dmd/root/longdouble.h

@@ -11,7 +11,7 @@
 
 #pragma once
 
-#if !_MSC_VER // has native 10 byte doubles
+#if !defined(_MSC_VER) || defined(_M_ARM64)
 #include <stdio.h>
 typedef long double longdouble;
 typedef volatile long double volatile_longdouble;
@@ -48,7 +48,7 @@ inline size_t ld_sprint(char* str, size_t size, int fmt, longdouble x)
 #undef snprintf
 #endif
 
-#else
+#else // defined(_MSC_VER) && !defined(_M_ARM64)
 
 #include <float.h>
 #include <limits>
@@ -264,4 +264,4 @@ typedef longdouble_soft longdouble;
 // is not required.
 typedef longdouble_soft volatile_longdouble;
 
-#endif // !_MSC_VER
+#endif // defined(_MSC_VER) && !defined(_M_ARM64)

gen/ctfloat.cpp

@@ -42,8 +42,8 @@ void CTFloat::initialize() {
   if (apSemantics)
     return;
 
-#ifdef _MSC_VER
-  // MSVC hosts use dmd.root.longdouble (80-bit x87)
+#if defined(_MSC_VER) && !defined(_M_ARM64)
+  // MSVC x86[_64] hosts use dmd.root.longdouble (80-bit x87)
   apSemantics = &APFloat::x87DoubleExtended();
 #else
   static_assert(std::numeric_limits<real_t>::is_specialized,