ci: extract the standard-config toolchain prologue into build-toolchain

.github/actions/build-toolchain/action.yml

@@ -0,0 +1,67 @@
+name: Build toolchain
+description: >-
+  Shared CI prologue for the standard toolchain configuration: submodule
+  checkout, Socket Firewall, platform prep (MSYS2 on Windows, disk cleanup
+  on macOS), then the LLVM and solc builds. The build parameters below
+  define the standard-config cache keys shared by test.yaml,
+  slang-tests.yaml, and cache-warmup.yaml — changing them here re-keys all
+  of those workflows together. Workflows needing a different LLVM
+  configuration (sanitizer, coverage, integration, release) call
+  build-llvm/build-solc directly and pair with their own cache-warmup job.
+
+inputs:
+  llvm:
+    description: Whether to build LLVM
+    required: false
+    default: 'true'
+  solc:
+    description: Whether to build solc
+    required: false
+    default: 'true'
+
+runs:
+  using: composite
+  steps:
+    - name: Checkout submodules
+      uses: ./.github/actions/checkout-submodules
+
+    - name: Setup SFW (optional)
+      uses: ./.github/actions/setup-sfw
+      with:
+        optional: 'true'
+
+    - name: Prepare Windows env
+      if: runner.os == 'Windows'
+      uses: ./.github/actions/prepare-msys
+
+    - name: Free disk space (macOS)
+      if: runner.os == 'macOS'
+      uses: ./.github/actions/free-disk-space-macos
+
+    - name: Build LLVM
+      if: inputs.llvm == 'true'
+      uses: ./.github/actions/build-llvm
+      with:
+        build-type: RelWithDebInfo
+        enable-assertions: 'true'
+        enable-mlir: 'true'
+        enable-utils: 'true'
+
+    # Fresh llvm-sys objects under MSYS2 GCC 16 cannot link against the
+    # static libstdc++.a that solx-dev bundles into the LLVM tree; dropping
+    # it resolves -lstdc++ to the shared libstdc++.dll.a instead (#550, fix
+    # option 2). Test builds link libstdc++ shared; release binaries keep
+    # static linking (release.yaml builds LLVM itself and does not use this
+    # action). Runs after build-llvm's mid-action cache save, so the shared
+    # cached tree keeps the archive.
+    - name: Drop bundled static libstdc++ (Windows)
+      if: runner.os == 'Windows' && inputs.llvm == 'true'
+      shell: bash
+      run: rm -v target-llvm/target-final/lib/libstdc++.a
+
+    - name: Build solc
+      if: inputs.solc == 'true'
+      uses: ./.github/actions/build-solc
+      with:
+        cmake-build-type: RelWithDebInfo
+        working-dir: 'solx-solidity'

.github/workflows/cache-warmup.yaml

@@ -68,27 +68,10 @@ jobs:
         if: runner.os == 'Linux' && matrix.image != ''
         uses: ./.github/actions/free-disk-space-linux
 
-      - name: Checkout submodules
-        run: |
-          git config --global --add safe.directory '*'
-          git submodule update --force --depth=1 --recursive --checkout
-
-      - name: Prepare Windows env
-        if: runner.os == 'Windows'
-        uses: ./.github/actions/prepare-msys
-
-      - name: Setup SFW (optional)
-        uses: ./.github/actions/setup-sfw
+      - name: Build toolchain
+        uses: ./.github/actions/build-toolchain
         with:
-          optional: 'true'
-
-      - name: Build LLVM
-        uses: ./.github/actions/build-llvm
-        with:
-          build-type: RelWithDebInfo
-          enable-assertions: 'true'
-          enable-mlir: 'true'
-          enable-utils: 'true'
+          solc: 'false'
 
       # When the artifact cache is warm, build-llvm skips ccache entirely,
       # so the ccache entry's LRU timer isn't refreshed. Touch it explicitly
@@ -144,26 +127,10 @@ jobs:
         if: runner.os == 'Linux' && matrix.image != ''
         uses: ./.github/actions/free-disk-space-linux
 
-      - name: Checkout submodules
-        run: |
-          git config --global --add safe.directory '*'
-          git submodule update --force --depth=1 --recursive --checkout
-
-      - name: Prepare Windows env
-        if: runner.os == 'Windows'
-        uses: ./.github/actions/prepare-msys
-
-      - name: Setup SFW (optional)
-        uses: ./.github/actions/setup-sfw
+      - name: Build toolchain
+        uses: ./.github/actions/build-toolchain
         with:
-          optional: 'true'
-
-      - name: Build solc
-        uses: ./.github/actions/build-solc
-        with:
-          cmake-build-type: RelWithDebInfo
-          boost-version: '1.83.0'
-          working-dir: 'solx-solidity'
+          llvm: 'false'
 
       - name: Touch solc ccache
         if: always()

.github/workflows/slang-tests.yaml

@@ -74,27 +74,12 @@ jobs:
         with:
           submodules: true
 
-      # This step is required to checkout submodules
-      # that are disabled in .gitmodules config
-      - name: Checkout submodules
-        uses: ./.github/actions/checkout-submodules
-
-      - name: Setup SFW (optional)
-        uses: ./.github/actions/setup-sfw
-        with:
-          optional: 'true'
-
-      - name: Prepare Windows env
-        if: runner.os == 'Windows'
-        uses: ./.github/actions/prepare-msys
-
-      - name: Build LLVM
-        uses: ./.github/actions/build-llvm
+      # solc is built separately below: the lit tests need a Release build
+      # against a synced solx-solidity, not the standard config.
+      - name: Build toolchain
+        uses: ./.github/actions/build-toolchain
         with:
-          build-type: RelWithDebInfo
-          enable-assertions: 'true'
-          enable-mlir: 'true'
-          enable-utils: 'true'
+          solc: 'false'
 
       # TODO: remove this step and the Build solc step below once the lit
       # tests stop running against solc.

.github/workflows/test.yaml

@@ -112,17 +112,10 @@ jobs:
       - name: Free disk space (Linux)
         uses: ./.github/actions/free-disk-space-linux
 
-      # This step is required to checkout submodules
-      # that are disabled in .gitmodules config
-      - name: Checkout submodules
-        run: |
-          git config --global --add safe.directory '*'
-          git submodule update --force --depth=1 --recursive --checkout
-
-      - name: Setup SFW (optional)
-        uses: ./.github/actions/setup-sfw
+      - name: Build toolchain
+        uses: ./.github/actions/build-toolchain
         with:
-          optional: 'true'
+          solc: 'false'
 
       - name: Cache cargo artifacts
         uses: Swatinem/rust-cache@c19371144df3bb44fab255c43d04cbc2ab54d1c4 # v2.9.1
@@ -131,14 +124,6 @@ jobs:
           cache-on-failure: true
           save-if: ${{ github.ref == 'refs/heads/main' }}
 
-      - name: Build LLVM
-        uses: ./.github/actions/build-llvm
-        with:
-          build-type: RelWithDebInfo
-          enable-assertions: 'true'
-          enable-mlir: 'true'
-          enable-utils: 'true'
-
       - name: Cargo checks
         uses: ./.github/actions/cargo-check
 
@@ -234,47 +219,19 @@ jobs:
         if: runner.os == 'Linux' && matrix.image != ''
         uses: ./.github/actions/free-disk-space-linux
 
-      # This step is required to checkout submodules
-      # that are disabled in .gitmodules config
-      - name: Checkout submodules
-        run: |
-          git config --global --add safe.directory '*'
-          git submodule update --force --depth=1 --recursive --checkout
-
-      - name: Setup SFW (optional)
-        uses: ./.github/actions/setup-sfw
-        with:
-          optional: 'true'
-
-      - name: Prepare Windows env
-        if: runner.os == 'Windows'
-        uses: ./.github/actions/prepare-msys
-
-      - name: Free disk space (macOS)
-        if: runner.os == 'macOS'
-        uses: ./.github/actions/free-disk-space-macos
+      - name: Build toolchain
+        uses: ./.github/actions/build-toolchain
 
+      # Positioned after build-toolchain: prepare-msys switches the rustup
+      # host, which is part of the cache key, so only the post-msys position
+      # matches the keys already saved on main.
       - name: Cache cargo artifacts
         uses: Swatinem/rust-cache@c19371144df3bb44fab255c43d04cbc2ab54d1c4 # v2.9.1
         with:
           prefix-key: build-and-test-v2
           cache-on-failure: true
           save-if: ${{ github.ref == 'refs/heads/main' }}
 
-      - name: Build LLVM
-        uses: ./.github/actions/build-llvm
-        with:
-          build-type: RelWithDebInfo
-          enable-assertions: 'true'
-          enable-mlir: 'true'
-          enable-utils: 'true'
-
-      - name: Building solc
-        uses: ./.github/actions/build-solc
-        with:
-          cmake-build-type: RelWithDebInfo
-          working-dir: 'solx-solidity'
-
       - name: Free disk space (remove LLVM source and build artifacts)
         shell: bash
         run: |