Integrate symgc in druntime

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

@@ -82,15 +82,9 @@ runs:
 
         arch='${{ inputs.arch }}'
 
-        # use assertions for untagged builds
-        assertsSuffix="-withAsserts"
-        if [[ '${{ github.ref }}' = refs/tags/* ]]; then
-          assertsSuffix=""
-        fi
-
         if [[ '${{ runner.os }}' == Windows ]]; then
           curl -fL --retry 3 --max-time 300 -o llvm.7z \
-            https://github.com/ldc-developers/llvm-project/releases/download/$tag/llvm-$version-windows-$arch$assertsSuffix.7z
+            https://github.com/ldc-developers/llvm-project/releases/download/$tag/llvm-$version-windows-$arch.7z
           mkdir llvm
           cd llvm
           7z x ../llvm.7z >/dev/null
@@ -103,7 +97,7 @@ runs:
             os=osx
           fi
           curl -fL --retry 3 --max-time 300 -o llvm.tar.xz \
-            https://github.com/ldc-developers/llvm-project/releases/download/$tag/llvm-$version-$os-$arch$assertsSuffix.tar.xz
+            https://github.com/ldc-developers/llvm-project/releases/download/$tag/llvm-$version-$os-$arch.tar.xz
           mkdir llvm
           tar -xf llvm.tar.xz --strip 1 -C llvm
           rm llvm.tar.xz
@@ -119,8 +113,8 @@ runs:
         sudo ln -sf ld.lld /usr/bin/ld
         ld --version
 
-    - name: Install ninja v1.12.1
-      uses: Ahajha/gha-setup-ninja@69595b0cf872acdad8ce599142fbdc88724b9a2b
+    # - name: Install ninja v1.12.1
+    #   uses: Ahajha/gha-setup-ninja@69595b0cf872acdad8ce599142fbdc88724b9a2b
 
     - name: Install D host compiler
       uses: dlang-community/setup-dlang@v1
@@ -136,7 +130,7 @@ runs:
       run: |
         set -euxo pipefail
         python3 --version
-        if [[ '${{ runner.os }}-${{ inputs.arch }}' == 'macOS-arm64' ]]; then
+        if [[ '${{ runner.os }}' == 'macOS' ]]; then
           brew install lit
         else
           python3 -m pip install --user lit psutil
@@ -164,7 +158,8 @@ runs:
 
         url='https://curl.se/windows/latest.cgi?p=win64-mingw.zip'
         if [[ '${{ inputs.arch }}' == x86 ]]; then
-          url='https://curl.se/windows/latest.cgi?p=win32-mingw.zip'
+          # this is the latest *official* 32-bit build
+          url='https://curl.se/windows/dl-8.15.0_5/curl-8.15.0_5-win32-mingw.zip'
         fi
 
         curl -fL --retry 3 --max-time 60 -o libcurl.zip "$url"

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

@@ -12,6 +12,29 @@ runs:
   using: composite
   steps:
 
+    - name: 'Linux(aarch64/x86_64) & Windows(x86_64): Build symgc'
+      if: (runner.os == 'Linux' && (inputs.arch == 'x86_64' || inputs.arch == 'aarch64')) || (runner.os == 'Windows' && inputs.arch == 'x64')
+      shell: bash
+      run: |
+        set -eux
+        cd runtime/symgc
+        # FIXME: hitting LLVM assertion with -g
+        DFLAGS="-O -g -singleobj -linkonce-templates" dub build -v --compiler=$PWD/../../../bootstrap-ldc/bin/ldc2
+        # extract single object file as symgc.o[bj]
+        if [[ '${{ runner.os }}' == Linux ]]; then
+          ls -l libsymgc.a
+          ar x libsymgc.a
+          mv *.o symgc.o
+          ls -l symgc.o
+        else
+          ls -l symgc.lib
+          #obj=$(lib.exe /nologo /list symgc.lib)
+          #lib.exe /nologo symgc.lib /extract:"$obj" /out:symgc.obj
+          llvm-ar x symgc.lib
+          mv *.obj symgc.obj
+          ls -l symgc.obj
+        fi
+
     - name: 'Posix: Build mimalloc'
       if: runner.os != 'Windows'
       uses: ./.github/actions/helper-mimalloc

.github/actions/4d-test-libs/action.yml

@@ -33,6 +33,10 @@ runs:
         if [[ '${{ runner.os }}' == macOS ]]; then
           # FIXME: https://github.com/dlang/phobos/issues/10730
           excludes+='|^std.experimental.allocator.building_blocks.allocator_list'
+          if [[ '${{ inputs.arch }}' == x86_64 ]]; then
+            # FIXME: regressed with image bump from macos-13 to macos-15-intel, apparently wrt. getpwnam_r() setting unexpected errno
+            excludes+='|^std.path'
+          fi
         fi
 
         ctest -j$N --output-on-failure -E "$excludes" --timeout 120

.github/actions/6-integration-test/action.yml

@@ -8,19 +8,29 @@ runs:
 
     - name: Generate hello.d
       shell: bash
-      run: echo 'void main() { import std.stdio; writefln("Hello world, %d bits", size_t.sizeof * 8); }' > ../hello.d
+      run: echo 'void main() { import std.stdio; writefln("Hello world, %d bits", size_t.sizeof * 8); auto dummyAlloc = new int; }' > ../hello.d
 
     - name: Run hello-world integration test with shared libs
       shell: bash
       run: |
         set -eux
+        symgc=0
+        if [[ -f runtime/symgc/symgc.o || -f runtime/symgc/symgc.obj ]]; then
+          symgc=1
+        fi
         cd ..
         if [[ '${{ runner.os }}' == Windows ]]; then
           # add druntime/Phobos DLL dir to PATH
           export PATH="$PWD/installed/bin:$PATH"
         fi
         installed/bin/ldc2 hello.d -link-defaultlib-shared
         ./hello
+        if [[ $symgc == 1 ]]; then
+          ./hello --DRT-gcopt="gc:sdc"
+          installed/bin/ldc2 hello.d
+          ./hello --DRT-gcopt="gc:sdc"
+          DRT_GCOPT="gc:sdc" ./hello
+        fi
         if [[ -d installed/lib32 ]]; then
           installed/bin/ldc2 hello.d -m32 -link-defaultlib-shared
           ./hello

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

@@ -68,8 +68,8 @@ runs:
         ldc2-multilib\bin\ldc2 -link-defaultlib-shared -m32 -run hello.d || exit /b
 
     # preliminary arm64 cross-compilation support
-    - name: Install ninja v1.12.1
-      uses: Ahajha/gha-setup-ninja@69595b0cf872acdad8ce599142fbdc88724b9a2b
+    # - name: Install ninja v1.12.1
+    #   uses: Ahajha/gha-setup-ninja@69595b0cf872acdad8ce599142fbdc88724b9a2b
     - name: Set VSDIR env variable
       shell: bash
       run: echo "VSDIR=$(vswhere -latest -property installationPath)" >> $GITHUB_ENV

.github/workflows/main.yml

@@ -6,6 +6,7 @@ on:
   push:
     branches-ignore:
       - 'merge-*' # don't run on pushes to merge-X.Y.Z branches, they are usually PRs
+      - 'symgc*'
     tags: # explicitly needed to run for all tags, due to the branches filter above
       - '**'
 
@@ -15,6 +16,7 @@ concurrency:
 
 env:
   LLVM_VERSION: 20.1.5
+  DRT_GCOPT: gc:conservative
 
 jobs:
   build-native:
@@ -71,7 +73,7 @@ jobs:
             with_pgo: true
 
           - job_name: macOS x86_64
-            os: macos-13
+            os: macos-15-intel
             arch: x86_64
             # https://github.com/ldc-developers/ldc/issues/4462:
             # When using LTO, we need to explicitly export ~all symbols for plugin support via `ld64 -exported_symbol '__*'`.
@@ -132,7 +134,7 @@ jobs:
           else
             # set up Alpine container
             apk add \
-              git cmake ninja-is-really-ninja g++ clang ldc lld llvm-dev llvm-static compiler-rt \
+              git cmake ninja-is-really-ninja g++ clang ldc dub lld llvm-dev llvm-static compiler-rt \
               libxml2-static zstd-static zlib-static \
               bash grep diffutils make curl 7zip perl
             # create missing 7za symlink

.github/workflows/supported_llvm_versions.yml

@@ -6,6 +6,7 @@ on:
   push:
     branches-ignore:
       - 'merge-*' # don't run on pushes to merge-X.Y.Z branches, they are usually PRs
+      - 'symgc*'
     tags: # explicitly needed to run for all tags, due to the branches filter above
       - '**'
 
@@ -54,8 +55,8 @@ jobs:
         with:
           submodules: true
           fetch-depth: 50
-      - name: Install ninja
-        uses: symmetryinvestments/gha-setup-ninja@v2
+      # - name: Install ninja
+      #   uses: symmetryinvestments/gha-setup-ninja@v2
       - name: Install D host compiler
         uses: dlang-community/setup-dlang@v1
         with:

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "phobos"]
 	path = runtime/phobos
-	url = https://github.com/ldc-developers/phobos.git
+	url = https://github.com/symmetryinvestments/phobos.git
+[submodule "runtime/symgc"]
+	path = runtime/symgc
+	url = https://github.com/symmetryinvestments/symgc.git

dmd/dinterpret.d

@@ -6763,8 +6763,9 @@ ThrownExceptionExp chainExceptions(ThrownExceptionExp oldest, ThrownExceptionExp
     }
     // Little sanity check to make sure it's really a Throwable
     ClassReferenceExp boss = oldest.thrown;
-    const next = 5;                         // index of Throwable.next
-    assert((*boss.value.elements)[next].type.ty == Tclass); // Throwable.next
+    const next = 5;                          // index of Throwable._nextInChainPtr
+    with ((*boss.value.elements)[next].type) // Throwable._nextInChainPtr
+        assert(ty == Tpointer || ty == Tclass);
     ClassReferenceExp collateral = newest.thrown;
     if (collateral.originalClass().isErrorException() && !boss.originalClass().isErrorException())
     {

runtime/CMakeLists.txt

@@ -537,16 +537,26 @@ macro(compile_druntime d_flags lib_suffix path_suffix emit_bc all_at_once single
     else()
         set(single_obj_name "")
     endif()
+    set(symgc_version "")
+    if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/symgc/symgc${CMAKE_C_OUTPUT_EXTENSION}" AND "${path_suffix}" STREQUAL "${LIB_SUFFIX}") # not for 32-bit druntime with MULTILIB=ON
+        set(symgc_version "-d-version=With_symgc")
+    endif()
     dc("${DRUNTIME_D}"
        "${RUNTIME_DIR}/src"
-       "-conf=;${d_flags};${DRUNTIME_EXTRA_FLAGS};-I${RUNTIME_DIR}/src"
+       "-conf=;${d_flags};${symgc_version};${DRUNTIME_EXTRA_FLAGS};-I${RUNTIME_DIR}/src"
        "${PROJECT_BINARY_DIR}/objects${target_suffix}"
        "${emit_bc}"
        "${all_at_once}"
        "${single_obj_name}"
        ${outlist_o}
        ${outlist_bc}
     )
+    if(symgc_version)
+        list(APPEND ${outlist_o} ${CMAKE_CURRENT_SOURCE_DIR}/symgc/symgc${CMAKE_C_OUTPUT_EXTENSION})
+        if(${emit_bc})
+            list(APPEND ${outlist_bc} ${CMAKE_CURRENT_SOURCE_DIR}/symgc/symgc${CMAKE_C_OUTPUT_EXTENSION})
+        endif()
+    endif()
 endmacro()
 
 # Sets up the targets for building the Phobos D object files, appending the

runtime/druntime/src/core/gc/config.d

@@ -12,12 +12,17 @@ import core.stdc.stdio : printf;
 
 __gshared Config config;
 
+private __gshared bool _initialized;
+
 struct Config
 {
     bool disable;            // start disabled
     bool fork = false;       // optional concurrent behaviour
     ubyte profile;           // enable profiling with summary when terminating program
-    string gc = "conservative"; // select gc implementation conservative|precise|manual
+    version (With_symgc)
+        string gc = "sdcq"; // pick the symgc in quiet mode by default.
+    else
+        string gc = "conservative"; // select gc implementation conservative|precise|manual
 
     @MemVal size_t initReserve;      // initial reserve (bytes)
     @MemVal size_t minPoolSize = 1  << 20;  // initial and minimum pool size (bytes)
@@ -31,7 +36,9 @@ struct Config
 
     bool initialize()
     {
-        return initConfigOptions(this, "gcopt");
+        if (!_initialized)
+            _initialized = initConfigOptions(this, "gcopt");
+        return _initialized;
     }
 
     void help() @nogc nothrow
@@ -52,7 +59,7 @@ struct Config
         auto _minPoolSize = minPoolSize.bytes2prettyStruct;
         auto _maxPoolSize = maxPoolSize.bytes2prettyStruct;
         auto _incPoolSize = incPoolSize.bytes2prettyStruct;
-        printf(" - select gc implementation (default = conservative)
+        printf(" - select gc implementation (default = %.*s)
 
     initReserve:N  - initial memory to reserve in MB (%lld%c)
     minPoolSize:N  - initial and minimum pool size in MB (%lld%c)
@@ -64,6 +71,7 @@ struct Config
 
     Memory-related values can use B, K, M or G suffixes.
 ".ptr,
+               cast(int)gc.length, gc.ptr,
                _initReserve.v, _initReserve.u,
                _minPoolSize.v, _minPoolSize.u,
                _maxPoolSize.v, _maxPoolSize.u,

runtime/druntime/src/core/gc/gcinterface.d

@@ -13,6 +13,8 @@
  */
 module core.gc.gcinterface;
 
+import core.thread.threadbase : ThreadBase;
+
 static import core.memory;
 alias BlkAttr = core.memory.GC.BlkAttr;
 alias BlkInfo = core.memory.GC.BlkInfo;
@@ -270,4 +272,32 @@ interface GC
      * Returns: true if successful.
      */
     bool shrinkArrayUsed(void[] slice, size_t existingUsed, bool atomic = false) nothrow;
+
+    /**
+     * Prepare a thread for use with the GC after the GC is initialized. Note
+     * that you can register an initThread function to call before the GC is
+     * initialized, see core.gc.registry.
+     *
+     * This function is always called *from* the thread as it is being started,
+     * before any static initializers. The thread object parameter may not yet
+     * be registered as `ThreadBase.getThis()`, as this is called before that
+     * happens.
+     */
+    void initThread(ThreadBase thread) nothrow @nogc;
+
+    /**
+     * Clean up any GC related data from the thread before it exits. There is
+     * no equivalent of this function as a hook before the GC is initialized.
+     * That is, the thread init function called before the GC is initialized
+     * (from the registry hook) should assume this function may not be called
+     * on termination if the GC is never initialized.
+     *
+     * Most times, this is called from the thread that is the given thread
+     * reference, but it's possible the `thread` parameter is not the same as
+     * the current thread.
+     *
+     * There is no guarantee the thread is still registered as
+     * `ThreadBase.getThis()`.
+     */
+    void cleanupThread(ThreadBase thread) nothrow @nogc;
 }