fix clang build issue.

.cargo/config.toml

@@ -1,3 +1,7 @@
+# We need lld to link libwebrtc.a successfully on aarch64-linux
+[target.aarch64-unknown-linux-gnu]
+rustflags = ["-C", "link-arg=-fuse-ld=lld"]
+
 [target.x86_64-pc-windows-msvc]
 rustflags = ["-C", "target-feature=+crt-static"]
 
@@ -14,4 +18,4 @@ rustflags = ["-C", "link-args=-ObjC"]
 rustflags = ["-C", "link-args=-ObjC"]
 
 [target.aarch64-apple-ios-sim]
-rustflags = ["-C", "link-args=-ObjC"]
+rustflags = ["-C", "link-args=-ObjC"]

.changeset/fix_clang_build_issue_from_zed_patches_949.md

@@ -0,0 +1,17 @@
+---
+webrtc-sys: patch
+webrtc-sys-build: patch
+libwebrtc: patch
+---
+
+# fix clang build issue from zed patches (#949)
+
+#950 by @cloudwebrtc
+
+* webrtc-sys: Use clang instead of gcc
+
+* Debug CI output for aarch64-linux
+
+* ci: Install lld for aarch64-linux FFI builders
+
+* webrtc-sys: Disable CREL

.github/workflows/builds.yml

@@ -76,7 +76,9 @@ jobs:
           sudo apt update -y
           # libasound2-dev is needed for local_audio example
           # libdrm, libgbm, libxfixes, libxdamage, libxrandr, libxcomposite and libglib are needed for DesktopCapturer
+          # lld is needed on aarch64 because GNU ld cannot link libwebrtc.a for some reason
           sudo apt install -y \
+            lld \
             libasound2-dev \
             libssl-dev \
             libx11-dev \

.github/workflows/ffi-builds.yml

@@ -180,7 +180,7 @@ jobs:
           docker run --rm -v $PWD:/workspace -w /workspace ${{ matrix.build_image }} bash -c "\
             uname -a; \
             export PATH=/root/.cargo/bin:\$PATH; \
-            yum install llvm llvm-libs -y; \
+            yum install llvm llvm-libs lld -y; \
             yum install clang -y; \
             yum install protobuf-compiler -y; \
             yum groupinstall 'Development Tools' -y; \

.github/workflows/webrtc-builds.yml

@@ -112,30 +112,6 @@ jobs:
         run: |
          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: |

webrtc-sys/build/src/lib.rs

@@ -28,7 +28,7 @@ use regex::Regex;
 use reqwest::StatusCode;
 
 pub const SCRATH_PATH: &str = "livekit_webrtc";
-pub const WEBRTC_TAG: &str = "webrtc-0001d84-2";
+pub const WEBRTC_TAG: &str = "webrtc-24f6822";
 pub const IGNORE_DEFINES: [&str; 2] = ["CR_CLANG_REVISION", "CR_XCODE_VERSION"];
 
 pub fn target_os() -> String {

webrtc-sys/libwebrtc/build_linux.sh

@@ -71,11 +71,12 @@ git apply "$COMMAND_DIR/patches/add_licenses.patch" -v --ignore-space-change --i
 git apply "$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 "$COMMAND_DIR/patches/force_gcc.patch" -v --ignore-space-change --ignore-whitespace --whitespace=nowarn
-
-cd ..
+# Disable CREL (compact relocations). Chromium's build enables experimental
+# CREL via -Wa,--crel which causes segfaults on aarch64-linux (and is known
+# broken on arm32 and s390x too).
+# See: https://crbug.com/376278218
+# See: https://github.com/zed-industries/zed/pull/51433#discussion_r2944567608
+git -C build apply "$COMMAND_DIR/patches/disable_crel.patch" -v --ignore-space-change --ignore-whitespace --whitespace=nowarn
 
 cd third_party
 
@@ -87,10 +88,6 @@ mkdir -p "$ARTIFACTS_DIR/lib"
 
 python3 "./src/build/linux/sysroot_scripts/install-sysroot.py" --arch="$arch"
 
-if [ "$arch" = "arm64" ]; then
-  sudo sed -i 's/__GLIBC_USE_ISOC2X[[:space:]]*1/__GLIBC_USE_ISOC2X\t0/' /usr/aarch64-linux-gnu/include/features.h
-fi
-
 debug="false"
 if [ "$profile" = "debug" ]; then
   debug="true"
@@ -119,7 +116,6 @@ args="is_debug=$debug  \
   symbol_level=0 \
   enable_iterator_debugging=false \
   use_rtti=true \
-  is_clang=false \
   rtc_use_x11=true"
 
 # generate ninja files
@@ -131,7 +127,7 @@ ninja -C "$OUTPUT_DIR" :default
 # make libwebrtc.a
 # don't include nasm
 ar -rc "$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" "$ARTIFACTS_DIR/lib/libwebrtc.a"
+src/third_party/llvm-build/Release+Asserts/bin/llvm-objcopy --redefine-syms="$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"

webrtc-sys/libwebrtc/patches/disable_crel.patch

@@ -0,0 +1,17 @@
+diff --git a/config/compiler/BUILD.gn b/config/compiler/BUILD.gn
+--- a/config/compiler/BUILD.gn
++++ b/config/compiler/BUILD.gn
+@@ -617,13 +617,6 @@ config("compiler") {
+    cflags += [ "-ffp-contract=off" ]
+    }
+
+-    # Enable ELF CREL (see crbug.com/357878242) for all platforms that use ELF
+-    # (excluding toolchains that use an older version of LLVM).
+-    if (is_linux && use_lld && !llvm_android_mainline &&
+-        default_toolchain != "//build/toolchain/cros:target") {
+-      cflags += [ "-Wa,--crel,--allow-experimental-crel" ]
+-    }
+-
+    # TODO(crbug.com/413427035): Remove once
+    # https://github.com/llvm/llvm-project/pull/136867/ is landed.
+    if (!is_win && !llvm_android_mainline &&