build libwebrtc from source during webrtc-sys build

.github/workflows/webrtc-builds.yml

@@ -15,8 +15,8 @@
 name: WebRTC builds
 on:
   push:
-    tags:
-      - "webrtc-*"
+#    tags:
+#      - "webrtc-*"
   workflow_dispatch:
 
 jobs:
@@ -47,12 +47,12 @@ jobs:
 
           - name: linux
             os: ubuntu-latest
-            cmd: ./build_linux.sh
+            cmd: ./build_linux.sh --toolchain chromium-llvm
             arch: x64
 
           - name: linux
             os: ubuntu-latest
-            cmd: ./build_linux.sh
+            cmd: ./build_linux.sh --toolchain chromium-llvm
             arch: arm64
 
           - name: android
@@ -110,38 +110,18 @@ jobs:
       - name: install setuptools (none-macOS)
         if: ${{ matrix.target.os != 'macos-latest' }}
         run: |
-         pip3 install setuptools # pkg_resources is sometimes not found?
+          pip3 install setuptools # pkg_resources is sometimes not found?
 
-      - name: Add GCC PPA and install GCC 14
-        if: ${{ matrix.target.os == 'ubuntu-latest' }}
-        run: |
-          sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y
-          sudo apt update
-          sudo apt install gcc-14 g++-14 g++-14-aarch64-linux-gnu -y
-
-      - name: Verify GCC 14 installation
-        if: ${{ matrix.target.os == 'ubuntu-latest' }}
-        run: |
-          gcc-14 --version
-          g++-14 --version
-          aarch64-linux-gnu-g++-14 --version
-
-      - name: Set GCC 14 as default (optional)
-        if: ${{ matrix.target.os == 'ubuntu-latest' }}
-        run: |
-          sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-14 140 --slave /usr/bin/g++ g++ /usr/bin/g++-14
-          sudo update-alternatives --config gcc
-          gcc --version
-          sudo update-alternatives --install /usr/bin/aarch64-linux-gnu-gcc aarch64-linux-gnu-gcc /usr/bin/aarch64-linux-gnu-gcc-14 140 --slave /usr/bin/aarch64-linux-gnu-g++ aarch64-linux-gnu-g++ /usr/bin/aarch64-linux-gnu-g++-14
-          sudo update-alternatives --config aarch64-linux-gnu-gcc
-          aarch64-linux-gnu-gcc --version
-
       - name: Install linux dependencies
         if: ${{ matrix.target.os == 'ubuntu-latest' }}
         run: |
           sudo apt update -y
           sudo apt install -y ninja-build pkg-config openjdk-11-jdk
 
+      - name: Disable __GLIBC_USE_ISOC2X macro
+        if: ${{ matrix.target.name == 'linux' && matrix.target.arch == 'arm64' }}
+        run: sudo sed -i 's/__GLIBC_USE_ISOC2X[[:space:]]*1/__GLIBC_USE_ISOC2X\t0/' /usr/include/features.h
+
       - name: Install macos dependencies
         if: ${{ matrix.target.os == 'macos-latest' }}
         run: brew install ninja

webrtc-sys/Cargo.toml

@@ -13,12 +13,15 @@ use_vaapi = []
 use_nvidia = []
 
 [dependencies]
-cxx = "1.0"
+# Copy an updated version of the cxx.cc file from cxx's repository
+# into the src directory when updating to a new version of cxx
+# and change the include path for cxx.h to "rust/cxx.h"
+cxx = "=1.0.186"
 log = "0.4"
 
 [build-dependencies]
 webrtc-sys-build = { workspace = true }
-cxx-build = "1.0"
+cxx-build = "=1.0.186"
 glob = "0.3"
 cc = "1.0"
 

webrtc-sys/build.rs

@@ -79,7 +79,54 @@ fn main() {
         "src/apm.cpp",
     ]);
 
-    let webrtc_dir = webrtc_sys_build::webrtc_dir();
+    let mut webrtc_dir = webrtc_sys_build::webrtc_dir();
+    let target_arch = env::var("CARGO_CFG_TARGET_ARCH").unwrap();
+
+    #[cfg(target_os = "linux")]
+    println!("cargo:rerun-if-env-changed=LK_LIBWEBRTC_SOURCE");
+    #[cfg(target_os = "linux")]
+    if let Ok(source_archive) = env::var("LK_LIBWEBRTC_SOURCE") {
+        let out_dir = env::var("OUT_DIR").unwrap();
+        let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
+
+        fn check_command_output(output: std::process::Output) {
+            let status = output.status;
+            if !status.success() {
+                let stderr = String::from_utf8_lossy(&output.stderr);
+                let stdout = String::from_utf8_lossy(&output.stdout);
+                panic!("Command exited unsuccessfully: {status:?},\nstdout:\n{stdout}\nstderr:\n{stderr}");
+            }
+        }
+
+        check_command_output(
+            Command::new("tar").args(["-Jxf", &source_archive, "-C", &out_dir]).output().unwrap(),
+        );
+
+        let script_arch = match target_arch.as_str() {
+            "x86_64" => "x64",
+            "aarch64" => "arm64",
+            a => a,
+        };
+        check_command_output(
+            Command::new("bash")
+                .args([
+                    &format!("{manifest_dir}/libwebrtc/build_linux.sh"),
+                    "--sources",
+                    &format!("{out_dir}/src"),
+                    "--toolchain",
+                    "gnu",
+                    "--arch",
+                    script_arch,
+                    "--profile",
+                    "release",
+                ])
+                .output()
+                .unwrap(),
+        );
+
+        webrtc_dir = PathBuf::from(format!("{out_dir}/linux-{script_arch}-release"));
+    }
+
     let webrtc_include = webrtc_dir.join("include");
     let webrtc_lib = webrtc_dir.join("lib");
 
@@ -110,7 +157,6 @@ fn main() {
     println!("cargo:rustc-link-lib=static=webrtc");
 
     let target_os = env::var("CARGO_CFG_TARGET_OS").unwrap();
-    let target_arch = env::var("CARGO_CFG_TARGET_ARCH").unwrap();
     match target_os.as_str() {
         "windows" => {
             println!("cargo:rustc-link-lib=dylib=msdmo");
@@ -148,6 +194,23 @@ fn main() {
                 .flag("/EHsc");
         }
         "linux" => {
+            // If libwebrtc was built with Chromium's libc++, the C++ in this crate needs to be built with it too.
+            let buildtools = webrtc_include.join("buildtools/third_party/libc++");
+            if buildtools.exists() {
+                // Chromium's libc++ doesn't build with GCC
+                if env::var("CC").is_err() {
+                    builder.compiler("clang++");
+                }
+                builder.include(buildtools);
+                builder.flag("-nostdinc++");
+                let webrtc_include = webrtc_include.to_string_lossy();
+                builder.flag(format!("-isystem{webrtc_include}/third_party/libc++/src/include"));
+                builder.flag(format!("-isystem{webrtc_include}/third_party/libc++abi/src/include"));
+                // The cxx crate builds this C++ file. However, this crate needs to rebuild it when using a
+                // different C++ standard library or linking will fail with unresolved symbol errors.
+                builder.file("src/cxx.cc");
+            }
+
             println!("cargo:rustc-link-lib=dylib=rt");
             println!("cargo:rustc-link-lib=dylib=dl");
             println!("cargo:rustc-link-lib=dylib=pthread");

webrtc-sys/libwebrtc/build_linux.sh

@@ -16,15 +16,16 @@
 
 arch=""
 profile="release"
+toolchain="gnu"
 
 while [ "$#" -gt 0 ]; do
   case "$1" in
+    --sources)
+      sources="$(realpath $2)"
+      shift 2
+      ;;
     --arch)
       arch="$2"
-      if [ "$arch" != "x64" ] && [ "$arch" != "arm64" ]; then
-        echo "Error: Invalid value for --arch. Must be 'x64' or 'arm64'."
-        exit 1
-      fi
       shift 2
       ;;
     --profile)
@@ -35,6 +36,14 @@ while [ "$#" -gt 0 ]; do
       fi
       shift 2
       ;;
+    --toolchain)
+      toolchain="$2"
+      if [ "$toolchain" != "gnu" ] && [ "$toolchain" != "llvm" ] && [ "$toolchain" != "chromium-llvm" ]; then
+        echo "Error: Invalid value for --toolchain. Must be 'gnu', 'llvm', or 'chromium-llvm' (Chromium's bundled Clang with Debian sysroot)"
+        exit 1
+      fi
+      shift 2
+      ;;
     *)
       echo "Error: Unknown argument '$1'"
       exit 1
@@ -47,48 +56,55 @@ if [ -z "$arch" ]; then
   exit 1
 fi
 
+if [ -z "$sources" ]; then
+  echo "Error: --sources must be set."
+  exit 1
+fi
+
 echo "Building LiveKit WebRTC - Linux"
 echo "Arch: $arch"
 echo "Profile: $profile"
-
-if [ ! -e "$(pwd)/depot_tools" ]
-then
-  git clone --depth 1 https://chromium.googlesource.com/chromium/tools/depot_tools.git
-fi
-
-export COMMAND_DIR=$(cd $(dirname $0); pwd)
-export PATH="$(pwd)/depot_tools:$PATH"
-export OUTPUT_DIR="$(pwd)/src/out-$arch-$profile"
-export ARTIFACTS_DIR="$(pwd)/linux-$arch-$profile"
-
-if [ ! -e "$(pwd)/src" ]
-then
-  gclient sync -D --no-history
-fi
-
-cd src
-git apply "$COMMAND_DIR/patches/add_licenses.patch" -v --ignore-space-change --ignore-whitespace --whitespace=nowarn
-git apply "$COMMAND_DIR/patches/ssl_verify_callback_with_native_handle.patch" -v --ignore-space-change --ignore-whitespace --whitespace=nowarn
-git apply "$COMMAND_DIR/patches/add_deps.patch" -v --ignore-space-change --ignore-whitespace --whitespace=nowarn
-
-cd build
-
-git apply "$COMMAND_DIR/patches/force_gcc.patch" -v --ignore-space-change --ignore-whitespace --whitespace=nowarn
-
-cd ..
-
-cd third_party
-
-git apply "$COMMAND_DIR/patches/david_disable_gun_source_macro.patch" -v --ignore-space-change --ignore-whitespace --whitespace=nowarn
-
-cd ../..
-
-mkdir -p "$ARTIFACTS_DIR/lib"
-
-python3 "./src/build/linux/sysroot_scripts/install-sysroot.py" --arch="$arch"
-
-if [ "$arch" = "arm64" ]; then
-  sudo sed -i 's/__GLIBC_USE_ISOC2X[[:space:]]*1/__GLIBC_USE_ISOC2X\t0/' /usr/aarch64-linux-gnu/include/features.h
+echo "Toolchain: $toolchain"
+
+COMMAND_DIR=$(cd $(dirname $0); pwd)
+OUTPUT_DIR="$(dirname "$sources")"
+BUILD_DIR="$OUTPUT_DIR/build-$arch-$profile"
+ARTIFACTS_DIR="$OUTPUT_DIR/linux-$arch-$profile"
+
+if [ "$toolchain" == "gnu" ]; then
+  [ -n "$CC" ] || export CC="$(which gcc)"
+  [ -n "$CXX" ] || export CXX="$(which g++)"
+  [ -n "$AR" ] || export AR="$(which ar)"
+  [ -n "$NM" ] || export NM="$(which nm)"
+  export CXXFLAGS="${CXXFLAGS} -Wno-changes-meaning -Wno-unknown-pragmas -D_DEFAULT_SOURCE"
+  OBJCOPY="$(which objcopy)"
+  chromium_libcxx=false
+  toolchain_gn_args="is_clang=false \
+  use_sysroot=false \
+  custom_toolchain=\"//build/toolchain/linux/unbundle:default\" \
+  host_toolchain=\"//build/toolchain/linux/unbundle:default\""
+elif [ "$toolchain" == "llvm" ]; then
+  [ -n "$CC" ] || export CC="$(which clang)"
+  [ -n "$CXX" ] || export CXX="$(which clang++)"
+  [ -n "$AR" ] || export AR="$(which llvm-ar)"
+  [ -n "$NM" ] || export NM="$(which llvm-nm)"
+  OBJCOPY="$(which llvm-objcopy)"
+  # Using system libc++ stumbles over
+  # https://github.com/llvm/llvm-project/issues/50248
+  # so use Chromium's libc++
+  chromium_libcxx=true
+  toolchain_gn_args="is_clang=true \
+  clang_use_chrome_plugins=false \
+  use_sysroot=false \
+  custom_toolchain=\"//build/toolchain/linux/unbundle:default\" \
+  host_toolchain=\"//build/toolchain/linux/unbundle:default\""
+elif [ "$toolchain" == "chromium-llvm" ]; then
+  AR="$sources/third_party/llvm-build/Release+Asserts/bin/llvm-ar"
+  OBJCOPY="$sources/third_party/llvm-build/Release+Asserts/bin/llvm-objcopy"
+  chromium_libcxx=true
+  toolchain_gn_args="is_clang=true \
+  use_custom_libcxx=true \
+  use_sysroot=true"
 fi
 
 debug="false"
@@ -101,7 +117,7 @@ args="is_debug=$debug  \
   target_cpu=\"$arch\" \
   rtc_enable_protobuf=false \
   treat_warnings_as_errors=false \
-  use_custom_libcxx=false \
+  use_custom_libcxx=${chromium_libcxx}
   use_llvm_libatomic=false \
   use_libcxx_modules=false \
   use_custom_libcxx_for_host=false \
@@ -119,27 +135,43 @@ args="is_debug=$debug  \
   symbol_level=0 \
   enable_iterator_debugging=false \
   use_rtti=true \
-  is_clang=false \
-  rtc_use_x11=false"
+  rtc_use_x11=false \
+  $toolchain_gn_args"
+
+set -xe
+
+if [ "$toolchain" == "chromium-llvm" ]; then
+  python3 "$sources/build/linux/sysroot_scripts/install-sysroot.py" --arch=x64
+  python3 "$sources/build/linux/sysroot_scripts/install-sysroot.py" --arch=arm64
+fi
 
 # generate ninja files
-gn gen "$OUTPUT_DIR" --root="src" --args="${args}"
+export PATH="$sources/depot_tools:$PATH"
+gn gen "$BUILD_DIR" --root="$sources" --args="${args}"
 
 # build static library
-ninja -C "$OUTPUT_DIR" :default
+ninja -C "$BUILD_DIR" :default
+
+mkdir -p "$ARTIFACTS_DIR/lib"
 
 # make libwebrtc.a
 # don't include nasm
-ar -rc "$ARTIFACTS_DIR/lib/libwebrtc.a" `find "$OUTPUT_DIR/obj" -name '*.o' -not -path "*/third_party/nasm/*"`
-objcopy --redefine-syms="$COMMAND_DIR/boringssl_prefix_symbols.txt" "$ARTIFACTS_DIR/lib/libwebrtc.a"
-
-python3 "./src/tools_webrtc/libs/generate_licenses.py" \
-  --target :default "$OUTPUT_DIR" "$OUTPUT_DIR"
-
-cp "$OUTPUT_DIR/obj/webrtc.ninja" "$ARTIFACTS_DIR"
-cp "$OUTPUT_DIR/args.gn" "$ARTIFACTS_DIR"
-cp "$OUTPUT_DIR/LICENSE.md" "$ARTIFACTS_DIR"
-
-cd src
+"$AR" -rc "$ARTIFACTS_DIR/lib/libwebrtc.a" `find "$BUILD_DIR/obj" -name '*.o' -not -path "*/third_party/nasm/*"`
+"$OBJCOPY" --redefine-syms="$COMMAND_DIR/boringssl_prefix_symbols.txt" "$ARTIFACTS_DIR/lib/libwebrtc.a"
+
+python3 "$sources/tools_webrtc/libs/generate_licenses.py" \
+  --target :default "$BUILD_DIR" "$BUILD_DIR"
+
+cp "$BUILD_DIR/obj/webrtc.ninja" "$ARTIFACTS_DIR"
+cp "$BUILD_DIR/args.gn" "$ARTIFACTS_DIR"
+cp "$BUILD_DIR/LICENSE.md" "$ARTIFACTS_DIR"
+
+cd $sources
+if [ $chromium_libcxx == "true" ]; then
+  mkdir -p "$ARTIFACTS_DIR/include/buildtools/third_party"
+  cp -R buildtools/third_party/libc++ "$ARTIFACTS_DIR/include/buildtools/third_party"
+  mkdir -p "$ARTIFACTS_DIR/include/third_party/libc++/src"
+  cp -R third_party/libc++/src/include "$ARTIFACTS_DIR/include/third_party/libc++/src"
+fi
 find . -name "*.h" -print | cpio -pd "$ARTIFACTS_DIR/include"
 find . -name "*.inc" -print | cpio -pd "$ARTIFACTS_DIR/include"