Add musl libc CI using Alpine Linux container on Ubuntu GHA (#4650)

* Add musl libc CI on Alpine Linux

* Fix gdb detection.
The pipe through `head` meant that error code was always 0, even when gdb is absent.

* Try a little harder to find compiler-rt libs, by also searching directory structure with major llvm version instead of x.y.z version.

* Add compiler-rt package

* TSan and XRay do not work on Alpine

* Add correct statvfs_t for Musl (upstreamed)

.github/workflows/alpine_musl.yml

@@ -0,0 +1,83 @@
+name: Alpine Linux (musl libc)
+on:
+  - pull_request
+  - push
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: Alpine Linux (musl libc)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+          fetch-depth: 50
+
+      - name: Setup latest Alpine Linux
+        uses: jirutka/setup-alpine@v1
+        with:
+          branch: v3.20
+          packages: ldc git g++ cmake ninja llvm-dev llvm-static compiler-rt libunwind-static libxml2-static zstd-static zlib-static bash grep diffutils make
+
+      - name: Build LDC bootstrap
+        shell: alpine.sh {0}
+        run: |
+          ninja --version
+          set -eux
+          mkdir bootstrap
+          cd bootstrap
+          cmake -G Ninja .. \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_INSTALL_PREFIX="/opt/ldc2" \
+            -DCMAKE_EXE_LINKER_FLAGS=-static-libstdc++ \
+            -DD_COMPILER_FLAGS=-link-defaultlib-shared=false \
+            -DBUILD_SHARED_LIBS=OFF
+          ninja obj/ldc2.o all
+          bin/ldc2 --version
+          cd ..
+
+      # TODO: Add '-DLLVM_IS_SHARED=OFF' when static linking is fully supported
+      # TSan and XRay do not work.
+      - name: Build LDC & LDC D unittests & defaultlib unittest runners
+        shell: alpine.sh {0}
+        run: |
+          set -eux
+          cmake -G Ninja . \
+            -DD_COMPILER=./bootstrap/bin/ldmd2 \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_INSTALL_PREFIX="/opt/ldc2" \
+            -DCMAKE_EXE_LINKER_FLAGS=-static-libstdc++ \
+            -DD_COMPILER_FLAGS=-link-defaultlib-shared=false \
+            -DBUILD_SHARED_LIBS=OFF \
+            -DTEST_COMPILER_RT_LIBRARIES="profile;lsan;asan;msan;fuzzer"
+          ninja obj/ldc2.o all ldc2-unittest all-test-runners
+          bin/ldc2 --version
+          ldd bin/ldc2
+
+      - name: Run LDC D unittests
+        if: success() || failure()
+        shell: alpine.sh {0}
+        run: ctest --output-on-failure -R "ldc2-unittest"
+
+      - name: Run LIT testsuite
+        if: success() || failure()
+        shell: alpine.sh {0}
+        run: |
+          set -eux
+          ctest -V -R "lit-tests"
+
+      - name: Run DMD testsuite
+        if: success() || failure()
+        shell: alpine.sh {0}
+        run: ctest -V -R "dmd-testsuite"
+
+      - name: Run defaultlib unittests & druntime integration tests
+        if: success() || failure()
+        shell: alpine.sh {0}
+        run: |
+          set -eux
+          ctest -j$(nproc) --output-on-failure -E "dmd-testsuite|lit-tests|ldc2-unittest"

driver/linker-gcc.cpp

@@ -257,23 +257,33 @@ std::string getCompilerRTLibFilename(const llvm::Twine &name,
 
 // Clang's RT libs are in a subdir of the lib dir.
 // E.g., for name="libclang_rt.asan" and sharedLibrary=true, returns
-// "clang/6.0.0/lib/darwin/libclang_rt.asan_osx_dynamic.dylib" on
+// "clang/6.0.0/lib/darwin/libclang_rt.asan_osx_dynamic.dylib" and
+// "clang/6/lib/darwin/libclang_rt.asan_osx_dynamic.dylib" on
 // Darwin.
 // This function is "best effort", the path may not be what Clang does...
 // See clang/lib/Driver/Toolchain.cpp.
-std::string getRelativeClangCompilerRTLibPath(const llvm::Twine &name,
-                                              const llvm::Triple &triple,
-                                              bool sharedLibrary) {
-  llvm::StringRef OSName =
-      triple.isOSDarwin()
-          ? "darwin"
-          : triple.isOSFreeBSD() ? "freebsd" : triple.getOSName();
+std::vector<std::string> getRelativeClangCompilerRTLibPath(
+    const llvm::Twine &name, const llvm::Triple &triple, bool sharedLibrary) {
+  llvm::StringRef OSName = triple.isOSDarwin()    ? "darwin"
+                           : triple.isOSFreeBSD() ? "freebsd"
+                                                  : triple.getOSName();
+
+  auto llvm_major_version =
+      llvm::StringRef(ldc::llvm_version_base).take_until([](char c) {
+        return c == '.';
+      });
 
   std::string relPath = (llvm::Twine("clang/") + ldc::llvm_version_base +
                          "/lib/" + OSName + "/" + name)
                             .str();
+  std::string relPath_llvm_major_version =
+      (llvm::Twine("clang/") + llvm_major_version + "/lib/" + OSName + "/" +
+       name)
+          .str();
 
-  return getCompilerRTLibFilename(relPath, triple, sharedLibrary);
+  return {getCompilerRTLibFilename(relPath, triple, sharedLibrary),
+          getCompilerRTLibFilename(relPath_llvm_major_version, triple,
+                                   sharedLibrary)};
 }
 
 void appendFullLibPathCandidates(std::vector<std::string> &paths,
@@ -299,7 +309,8 @@ void appendFullLibPathCandidates(std::vector<std::string> &paths,
 // E.g., for baseName="asan" and sharedLibrary=false, returns something like
 // [ "<libDir>/libldc_rt.asan.a",
 //   "<libDir>/libclang_rt.asan_osx.a",
-//   "<libDir>/clang/6.0.0/lib/darwin/libclang_rt.asan_osx.a" ].
+//   "<libDir>/clang/6.0.0/lib/darwin/libclang_rt.asan_osx.a",
+//   "<libDir>/clang/6/lib/darwin/libclang_rt.asan_osx.a" ].
 std::vector<std::string>
 getFullCompilerRTLibPathCandidates(llvm::StringRef baseName,
                                    const llvm::Triple &triple,
@@ -315,7 +326,9 @@ getFullCompilerRTLibPathCandidates(llvm::StringRef baseName,
   appendFullLibPathCandidates(r, clangRT);
   const auto fullClangRT = getRelativeClangCompilerRTLibPath(
       "libclang_rt." + baseName, triple, sharedLibrary);
-  appendFullLibPathCandidates(r, fullClangRT);
+  for (const auto &path : fullClangRT) {
+    appendFullLibPathCandidates(r, path);
+  }
   return r;
 }
 

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

@@ -84,7 +84,57 @@ version (CRuntime_Glibc) {
         int statvfs (const char * file, statvfs_t* buf);
         int fstatvfs (int fildes, statvfs_t *buf);
     }
+}
+else version (CRuntime_Musl)
+{
+    struct statvfs_t
+    {
+        c_ulong f_bsize;
+        c_ulong f_frsize;
+        fsblkcnt_t f_blocks;
+        fsblkcnt_t f_bfree;
+        fsblkcnt_t f_bavail;
+        fsfilcnt_t f_files;
+        fsfilcnt_t f_ffree;
+        fsfilcnt_t f_favail;
+        static if (true /+__BYTE_ORDER == __LITTLE_ENDIAN+/)
+        {
+            c_ulong f_fsid;
+            byte[2*int.sizeof-c_long.sizeof] __padding;
+        }
+        else
+        {
+            byte[2*int.sizeof-c_long.sizeof] __padding;
+            c_ulong f_fsid;
+        }
+        c_ulong f_flag;
+        c_ulong f_namemax;
+        uint    f_type;
+        int[5]  __reserved;
+    }
+
+    enum FFlag
+    {
+        ST_RDONLY = 1,        /* Mount read-only.  */
+        ST_NOSUID = 2,
+        ST_NODEV = 4,         /* Disallow access to device special files.  */
+        ST_NOEXEC = 8,        /* Disallow program execution.  */
+        ST_SYNCHRONOUS = 16,      /* Writes are synced at once.  */
+        ST_MANDLOCK = 64,     /* Allow mandatory locks on an FS.  */
+        ST_WRITE = 128,       /* Write on file/directory/symlink.  */
+        ST_APPEND = 256,      /* Append-only file.  */
+        ST_IMMUTABLE = 512,       /* Immutable file.  */
+        ST_NOATIME = 1024,        /* Do not update access times.  */
+        ST_NODIRATIME = 2048,     /* Do not update directory access times.  */
+        ST_RELATIME = 4096        /* Update atime relative to mtime/ctime.  */
+
+    }
+
+    int statvfs (const char * file, statvfs_t* buf);
+    int fstatvfs (int fildes, statvfs_t *buf);
 
+    alias statvfs statvfs64;
+    alias fstatvfs fstatvfs64;
 }
 else version (NetBSD)
 {

tests/dmd/CMakeLists.txt

@@ -7,14 +7,16 @@ endif()
 if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
     set(gdb_result_code)
     execute_process(COMMAND gdb --version
-                    COMMAND head -n 1
-                    RESULT_VARIABLE gdb_result_code
-                    OUTPUT_VARIABLE GDB_VERSION
-                    OUTPUT_STRIP_TRAILING_WHITESPACE)
+                    RESULT_VARIABLE gdb_result_code)
     if(gdb_result_code)
         message(STATUS "GDB not detected, will exclude GDB tests from test suite")
         set(gdb_flags "OFF")
     else()
+        execute_process(COMMAND gdb --version
+                        COMMAND head -n 1
+                        RESULT_VARIABLE gdb_result_code
+                        OUTPUT_VARIABLE GDB_VERSION
+                        OUTPUT_STRIP_TRAILING_WHITESPACE)
         string(REGEX REPLACE "[^0-9]*([0-9]+[0-9.]*).*" "\\1" GDB_VERSION "${GDB_VERSION}")
         message(STATUS "GDB ${GDB_VERSION} detected")
         set(gdb_flags "ON")