diff --git a/build/build-clang/clang-18.json b/build/build-clang/clang-18.json
new file mode 100644
index 000000000000..5f66e5894708
--- /dev/null
+++ b/build/build-clang/clang-18.json
@@ -0,0 +1,21 @@
+{
+    "patches": [
+        "allow-unversioned-android.patch",
+        "find_symbolizer_linux_clang_15.patch",
+        "android-mangling-error_clang_12.patch",
+        "unpoison-thread-stacks_clang_10.patch",
+        "downgrade-mangling-error_clang_12.patch",
+        "fuzzing_ccov_build_clang_12.patch",
+        "revert-llvmorg-18-init-6208-g2baf4a06ef06.patch",
+        "revert-llvmorg-18-init-6193-gb88cffeafd39.patch",
+        "revert-llvmorg-18-init-6188-gc649f29c24c9.patch",
+        "partial-revert-llvmorg-17-init-17713-gc8e055d485ea.patch",
+        "revert-llvmorg-17-init-4120-g02e8eb1a438b_clang_18.patch",
+        "partial-revert-llvmorg-16-init-17151-gaa0883b59ae1_clang_17.patch",
+        "revert-llvmorg-16-init-11301-g163bb6d64e5f_clang_18.patch",
+        "revert-llvmorg-15-init-13446-g7524fe962e47.patch",
+        "revert-llvmorg-15-init-11205-gcead4eceb01b_clang_18.patch",
+        "win64-ret-null-on-commitment-limit_clang_14.patch",
+        "compiler-rt-rss-limit-heap-profile.patch"
+    ]
+}
diff --git a/taskcluster/ci/fetch/toolchains.yml b/taskcluster/ci/fetch/toolchains.yml
index 43f9d1bbca37..7649d974e6a6 100644
--- a/taskcluster/ci/fetch/toolchains.yml
+++ b/taskcluster/ci/fetch/toolchains.yml
@@ -362,6 +362,13 @@ clang-17:
         repo: https://github.com/llvm/llvm-project
         revision: 6009708b4367171ccdbf4b5905cb6a803753fe18
 
+clang-18:
+    description: clang 18.1.0-rc2 source code
+    fetch:
+        type: git
+        repo: https://github.com/llvm/llvm-project
+        revision: c6c86965d967886ca5a2ed8968c949cd42cdd49a
+
 clang-trunk:
     description: clang main branch source code
     attributes:
diff --git a/taskcluster/ci/toolchain/clang.yml b/taskcluster/ci/toolchain/clang.yml
index 97e23812d789..1223afd4e539 100644
--- a/taskcluster/ci/toolchain/clang.yml
+++ b/taskcluster/ci/toolchain/clang.yml
@@ -505,6 +505,366 @@ win64-clang-17:
             - win32-compiler-rt-17
             - win64-compiler-rt-17
 
+linux64-clang-18-mingw-x86:
+    description: "MinGW-Clang 18 x86 toolchain build"
+    treeherder:
+        symbol: TMW(clang-18-x86)
+    worker-type: b-linux-gcp
+    run:
+        script: build-clang-mingw.sh
+        arguments:
+            - 'x86'
+        resources:
+            - 'taskcluster/scripts/misc/mingw-*.patch'
+        toolchain-artifact: public/build/clangmingw.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+            - mingw-w64
+            - llvm-mingw
+            - gcc-9.5.0
+        toolchain:
+            - linux64-clang-18
+
+linux64-clang-18-mingw-x64:
+    description: "MinGW-Clang 18 x64 toolchain build"
+    treeherder:
+        symbol: TMW(clang-18-x64)
+        tier: 1
+    worker-type: b-linux-gcp
+    run:
+        script: build-clang-mingw.sh
+        arguments:
+            - 'x64'
+        resources:
+            - 'taskcluster/scripts/misc/mingw-*.patch'
+        toolchain-artifact: public/build/clangmingw.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+            - mingw-w64
+            - llvm-mingw
+            - gcc-9.5.0
+        toolchain:
+            - linux64-clang-18
+
+linux64-clang-18-stage1:
+    description: "Clang 18 toolchain build"
+    treeherder:
+        symbol: TL(clang-18-stage1)
+    run:
+        using: toolchain-script
+        script: build-clang.sh
+        arguments:
+            - 'build/build-clang/linux64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/1stage.json'
+        resources:
+            - 'build/build-clang/linux64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/1stage.json'
+        toolchain-artifact: public/build/clang.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-toolchain-sysroot
+
+linux64-clang-18-profile:
+    description: "Clang 18 toolchain build"
+    treeherder:
+        symbol: TL(clang-18-profile)
+    run:
+        using: toolchain-script
+        script: build-clang.sh
+        arguments:
+            - 'build/build-clang/linux64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/skip-stage-1.json'
+            - 'build/build-clang/profile.json'
+        resources:
+            - 'build/build-clang/linux64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/skip-stage-1.json'
+            - 'build/build-clang/profile.json'
+        toolchain-artifact: public/build/merged.profdata
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - linux64-x64-compiler-rt-18
+            - linux64-toolchain-sysroot
+
+linux64-clang-18-raw:
+    description: "Clang 18 toolchain build"
+    treeherder:
+        symbol: TL(clang-18-raw)
+    run:
+        script: build-clang.sh
+        arguments:
+            - 'build/build-clang/linux64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/skip-3-stages.json'
+            - 'build/build-clang/4stages-pgo.json'
+        resources:
+            - 'build/build-clang/linux64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/skip-3-stages.json'
+            - 'build/build-clang/4stages-pgo.json'
+        toolchain-artifact: public/build/clang.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - linux64-clang-18-profile
+            - linux64-toolchain-sysroot
+
+linux64-clang-18:
+    description: "Clang 18 toolchain build"
+    attributes:
+        local-toolchain: true
+    treeherder:
+        symbol: TL(clang-18)
+    worker-type: b-linux-gcp
+    worker:
+        max-run-time: 600
+    run:
+        script: repack-clang.sh
+        toolchain-artifact: public/build/clang.tar.zst
+    fetches:
+        toolchain:
+            - linux64-cctools-port
+            - linux64-clang-18-raw
+            - android-aarch64-compiler-rt-18
+            - android-aarch64-libunwind-18
+            - android-arm-compiler-rt-18
+            - android-arm-libunwind-18
+            - android-x64-compiler-rt-18
+            - android-x64-libunwind-18
+            - android-x86-compiler-rt-18
+            - android-x86-libunwind-18
+            - linux64-aarch64-compiler-rt-18
+            - linux64-x64-compiler-rt-18
+            - linux64-x86-compiler-rt-18
+            - macosx64-aarch64-compiler-rt-18
+            - macosx64-x64-compiler-rt-18
+            - wasm32-wasi-compiler-rt-18
+            - win32-compiler-rt-18
+            - win64-compiler-rt-18
+
+macosx64-clang-18-raw:
+    description: "Clang 18 toolchain build"
+    treeherder:
+        symbol: TM(clang-18-raw)
+    worker-type: b-linux-large-gcp
+    worker:
+        max-run-time: 3600
+    run:
+        script: build-clang.sh
+        arguments:
+            - 'build/build-clang/macosx64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/skip-3-stages.json'
+            - 'build/build-clang/4stages-pgo.json'
+        resources:
+            - 'build/build-clang/macosx64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/skip-3-stages.json'
+            - 'build/build-clang/4stages-pgo.json'
+        toolchain-artifact: public/build/clang.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - linux64-clang-18-profile
+            - macosx64-sdk-toolchain
+            - macosx64-x64-compiler-rt-18
+
+macosx64-clang-18:
+    description: "Clang 18 toolchain repack with MacOS Compiler RT libs"
+    attributes:
+        local-toolchain: true
+    treeherder:
+        symbol: TM(clang-18)
+    worker-type: b-linux-gcp
+    worker:
+        max-run-time: 600
+    run:
+        script: repack-clang.sh
+        toolchain-artifact: public/build/clang.tar.zst
+    fetches:
+        toolchain:
+            - linux64-cctools-port
+            - macosx64-clang-18-raw
+            - android-aarch64-compiler-rt-18
+            - android-aarch64-libunwind-18
+            - android-arm-compiler-rt-18
+            - android-arm-libunwind-18
+            - android-x64-compiler-rt-18
+            - android-x64-libunwind-18
+            - android-x86-compiler-rt-18
+            - android-x86-libunwind-18
+            - linux64-aarch64-compiler-rt-18
+            - linux64-x64-compiler-rt-18
+            - linux64-x86-compiler-rt-18
+            - macosx64-aarch64-compiler-rt-18
+            - macosx64-x64-compiler-rt-18
+            - wasm32-wasi-compiler-rt-18
+            - win32-compiler-rt-18
+            - win64-compiler-rt-18
+
+macosx64-aarch64-clang-18-raw:
+    description: "Clang 18 toolchain build"
+    treeherder:
+        symbol: TM(clang-18-aarch64-raw)
+    worker-type: b-linux-large-gcp
+    worker:
+        max-run-time: 3600
+    run:
+        script: build-clang.sh
+        arguments:
+            - 'build/build-clang/macosx64.json'
+            - 'build/build-clang/macosx64-aarch64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/skip-3-stages.json'
+            - 'build/build-clang/4stages-pgo.json'
+        resources:
+            - 'build/build-clang/macosx64.json'
+            - 'build/build-clang/macosx64-aarch64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/skip-3-stages.json'
+            - 'build/build-clang/4stages-pgo.json'
+        toolchain-artifact: public/build/clang.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - linux64-clang-18-profile
+            - macosx64-sdk-toolchain
+            - macosx64-aarch64-compiler-rt-18
+
+macosx64-aarch64-clang-18:
+    description: "Clang 18 toolchain repack with MacOS Compiler RT libs"
+    attributes:
+        local-toolchain: true
+    treeherder:
+        symbol: TM(clang-18-aarch64)
+    worker-type: b-linux-gcp
+    worker:
+        max-run-time: 600
+    run:
+        script: repack-clang.sh
+        toolchain-artifact: public/build/clang.tar.zst
+    fetches:
+        toolchain:
+            - linux64-cctools-port
+            - macosx64-aarch64-clang-18-raw
+            - android-aarch64-compiler-rt-18
+            - android-aarch64-libunwind-18
+            - android-arm-compiler-rt-18
+            - android-arm-libunwind-18
+            - android-x64-compiler-rt-18
+            - android-x64-libunwind-18
+            - android-x86-compiler-rt-18
+            - android-x86-libunwind-18
+            - linux64-aarch64-compiler-rt-18
+            - linux64-x64-compiler-rt-18
+            - linux64-x86-compiler-rt-18
+            - macosx64-aarch64-compiler-rt-18
+            - macosx64-x64-compiler-rt-18
+            - wasm32-wasi-compiler-rt-18
+            - win32-compiler-rt-18
+            - win64-compiler-rt-18
+
+win64-clang-18-stage1:
+    description: "Clang-cl 18 toolchain build stage 1"
+    treeherder:
+        symbol: TW64(clang-18-stage1)
+    run:
+        script: build-clang.sh
+        arguments:
+            - 'build/build-clang/win64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/1stage.json'
+        resources:
+            - 'build/build-clang/win64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/1stage.json'
+        toolchain-artifact: public/build/clang.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - vs-toolchain
+
+win64-clang-18-raw:
+    description: "Clang-cl 18 toolchain build"
+    treeherder:
+        symbol: TW64(clang-18-raw)
+    worker-type: b-win2022
+    worker:
+        max-run-time: 9000
+    run:
+        script: build-clang.sh
+        arguments:
+            - 'build/build-clang/win64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/skip-stage-1-win64.json'
+            - 'build/build-clang/4stages-pgo.json'
+        resources:
+            - 'build/build-clang/win64.json'
+            - 'build/build-clang/clang-18.json'
+            - 'build/build-clang/skip-stage-1-win64.json'
+            - 'build/build-clang/4stages-pgo.json'
+        toolchain-artifact: public/build/clang.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+            - cmake
+            - ninja
+        toolchain:
+            - win64-clang-18-stage1
+            - win64-compiler-rt-18
+            - vs-toolchain
+
+win64-clang-18:
+    description: "Clang-cl 18 toolchain build"
+    attributes:
+        local-toolchain: true
+    treeherder:
+        symbol: TW64(clang-18)
+    worker-type: b-linux-gcp
+    worker:
+        max-run-time: 600
+    run:
+        script: repack-clang.sh
+        toolchain-artifact: public/build/clang.tar.zst
+    fetches:
+        toolchain:
+            - linux64-cctools-port
+            - win64-clang-18-raw
+            - android-aarch64-compiler-rt-18
+            - android-aarch64-libunwind-18
+            - android-arm-compiler-rt-18
+            - android-arm-libunwind-18
+            - android-x64-compiler-rt-18
+            - android-x64-libunwind-18
+            - android-x86-compiler-rt-18
+            - android-x86-libunwind-18
+            - linux64-aarch64-compiler-rt-18
+            - linux64-x64-compiler-rt-18
+            - linux64-x86-compiler-rt-18
+            - macosx64-aarch64-compiler-rt-18
+            - macosx64-x64-compiler-rt-18
+            - wasm32-wasi-compiler-rt-18
+            - win32-compiler-rt-18
+            - win64-compiler-rt-18
+
 linux64-clang-trunk-mingw-x86:
     description: "MinGW-Clang trunk x86 toolchain build"
     attributes:
diff --git a/taskcluster/ci/toolchain/compiler-rt.yml b/taskcluster/ci/toolchain/compiler-rt.yml
index 1b31c12e4ff5..631024fbf9f5 100644
--- a/taskcluster/ci/toolchain/compiler-rt.yml
+++ b/taskcluster/ci/toolchain/compiler-rt.yml
@@ -246,6 +246,223 @@ wasm32-wasi-compiler-rt-17:
         toolchain:
             - linux64-clang-17-stage1
 
+android-aarch64-compiler-rt-18:
+    description: "android aarch64 Compiler-rt for Clang 18 toolchain build"
+    treeherder:
+        symbol: TA(aarch64-crt-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/compiler-rt-aarch64-linux-android.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - linux64-android-ndk-linux-repack
+
+android-arm-compiler-rt-18:
+    description: "android arm Compiler-rt for Clang 18 toolchain build"
+    treeherder:
+        symbol: TA(arm-crt-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/compiler-rt-armv7-linux-android.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - linux64-android-ndk-linux-repack
+
+android-x86-compiler-rt-18:
+    description: "android x86 Compiler-rt for Clang 18 toolchain build"
+    treeherder:
+        symbol: TA(x86-crt-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/compiler-rt-i686-linux-android.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - linux64-android-ndk-linux-repack
+
+android-x64-compiler-rt-18:
+    description: "android x64 Compiler-rt for Clang 18 toolchain build"
+    treeherder:
+        symbol: TA(x64-crt-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/compiler-rt-x86_64-linux-android.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - linux64-android-ndk-linux-repack
+
+linux64-x86-compiler-rt-18:
+    description: "Linux x86 Compiler-rt for Clang 18 toolchain build"
+    treeherder:
+        symbol: TL(x86-crt-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/compiler-rt-i686-unknown-linux-gnu.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - sysroot-i686-linux-gnu
+
+linux64-x64-compiler-rt-18:
+    description: "Linux x64 Compiler-rt for Clang 18 toolchain build"
+    treeherder:
+        symbol: TL(x64-crt-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/compiler-rt-x86_64-unknown-linux-gnu.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - sysroot-x86_64-linux-gnu
+
+linux64-aarch64-compiler-rt-18:
+    description: "Linux aarch64 Compiler-rt for Clang 18 toolchain build"
+    treeherder:
+        symbol: TL(aarch64-crt-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/compiler-rt-aarch64-unknown-linux-gnu.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - sysroot-aarch64-linux-gnu
+
+macosx64-x64-compiler-rt-18:
+    description: "macOS x64 Compiler-rt for Clang 18 toolchain build"
+    treeherder:
+        symbol: TM(x64-crt-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/compiler-rt-x86_64-apple-darwin.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - macosx64-sdk-toolchain
+
+macosx64-aarch64-compiler-rt-18:
+    description: "macOS aarch64 Compiler-rt for Clang 18 toolchain build"
+    treeherder:
+        symbol: TM(aarch64-crt-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/compiler-rt-aarch64-apple-darwin.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - macosx64-sdk-toolchain
+
+win32-compiler-rt-18:
+    description: "win32 x86 Compiler-rt for Clang 18 toolchain build"
+    treeherder:
+        symbol: TW32(crt-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/compiler-rt-i686-pc-windows-msvc.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - vs-toolchain
+
+win64-compiler-rt-18:
+    description: "win64 x64 Compiler-rt for Clang 18 toolchain build"
+    treeherder:
+        symbol: TW64(crt-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/compiler-rt-x86_64-pc-windows-msvc.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - vs-toolchain
+
+wasm32-wasi-compiler-rt-18:
+    description: "wasm32-wasi Compiler-rt for Clang 18 toolchain build"
+    treeherder:
+        symbol: TL(wasi-crt-18)
+    worker-type: b-linux-xlarge-gcp
+    run:
+        script: build-compiler-rt-wasi.sh
+        arguments:
+            - wasi-sdk.patch
+        resources:
+            - taskcluster/scripts/misc/wasi-sdk.patch
+        toolchain-artifact: public/build/compiler-rt-wasm32-wasi.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+            - wasi-sdk
+        toolchain:
+            - linux64-clang-18-stage1
+
 android-aarch64-compiler-rt-trunk:
     description: "android aarch64 Compiler-rt for Clang trunk toolchain build"
     attributes:
diff --git a/taskcluster/ci/toolchain/libunwind.yml b/taskcluster/ci/toolchain/libunwind.yml
index fa1c9afc1fcd..5a1972f3f651 100644
--- a/taskcluster/ci/toolchain/libunwind.yml
+++ b/taskcluster/ci/toolchain/libunwind.yml
@@ -86,6 +86,82 @@ android-x64-libunwind-17:
             - linux64-clang-17-stage1
             - linux64-android-ndk-linux-repack
 
+android-aarch64-libunwind-18:
+    description: "android aarch64 libunwind for Clang 18 toolchain build"
+    treeherder:
+        symbol: TA(aarch64-unwind-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/libunwind-aarch64-linux-android.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - android-aarch64-compiler-rt-18
+            - linux64-clang-18-stage1
+            - linux64-android-ndk-linux-repack
+
+android-arm-libunwind-18:
+    description: "android arm libunwind for Clang 18 toolchain build"
+    treeherder:
+        symbol: TA(arm-unwind-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/libunwind-armv7-linux-android.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - android-arm-compiler-rt-18
+            - linux64-clang-18-stage1
+            - linux64-android-ndk-linux-repack
+
+android-x86-libunwind-18:
+    description: "android x86 libunwind for Clang 18 toolchain build"
+    treeherder:
+        symbol: TA(x86-unwind-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/libunwind-i686-linux-android.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - android-x86-compiler-rt-18
+            - linux64-clang-18-stage1
+            - linux64-android-ndk-linux-repack
+
+android-x64-libunwind-18:
+    description: "android x64 libunwind for Clang 18 toolchain build"
+    treeherder:
+        symbol: TA(x64-unwind-18)
+    run:
+        arguments:
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+        toolchain-artifact: public/build/libunwind-x86_64-linux-android.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - android-x64-compiler-rt-18
+            - linux64-clang-18-stage1
+            - linux64-android-ndk-linux-repack
+
 android-aarch64-libunwind-trunk:
     description: "android aarch64 libunwind for Clang trunk toolchain build"
     attributes:
diff --git a/taskcluster/ci/toolchain/llvm-symbolizer.yml b/taskcluster/ci/toolchain/llvm-symbolizer.yml
index 6d2ceb744f8e..8864a81cc128 100644
--- a/taskcluster/ci/toolchain/llvm-symbolizer.yml
+++ b/taskcluster/ci/toolchain/llvm-symbolizer.yml
@@ -120,6 +120,96 @@ win64-llvm-symbolizer-17:
             - linux64-clang-17-stage1
             - vs-toolchain
 
+linux32-llvm-symbolizer-18:
+    description: "llvm-symbolizer for Linux"
+    treeherder:
+        symbol: TL32(llvm-symbolizer-18)
+    run:
+        arguments:
+            - i686-unknown-linux-gnu
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - linux32-toolchain-sysroot
+
+linux64-llvm-symbolizer-18:
+    description: "llvm-symbolizer for Linux"
+    treeherder:
+        symbol: TL(llvm-symbolizer-18)
+    run:
+        arguments:
+            - x86_64-unknown-linux-gnu
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - linux64-toolchain-sysroot
+
+macosx64-llvm-symbolizer-18:
+    description: "llvm-symbolizer for macOS x64"
+    treeherder:
+        symbol: TM(llvm-symbolizer-18)
+    run:
+        arguments:
+            - x86_64-apple-darwin
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - macosx64-sdk-toolchain
+
+macosx64-aarch64-llvm-symbolizer-18:
+    description: "llvm-symbolizer for macOS aarch64"
+    treeherder:
+        symbol: TM(llvm-sym-aarch64-18)
+    run:
+        arguments:
+            - aarch64-apple-darwin
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - macosx64-sdk-toolchain
+
+win64-llvm-symbolizer-18:
+    description: "llvm-symbolizer for Windows"
+    treeherder:
+        symbol: TW64(llvm-symbolizer-18)
+    run:
+        arguments:
+            - x86_64-pc-windows-msvc
+            - build/build-clang/clang-18.json
+        resources:
+            - build/build-clang/clang-18.json
+            - taskcluster/scripts/misc/build-llvm-common.sh
+    fetches:
+        fetch:
+            - clang-18
+        toolchain:
+            - linux64-clang-18-stage1
+            - vs-toolchain
+
 linux32-llvm-symbolizer-trunk:
     description: "llvm-symbolizer for Linux"
     attributes:
diff --git a/taskcluster/ci/toolchain/sysroot.yml b/taskcluster/ci/toolchain/sysroot.yml
index 149840bc0cff..e4479d16e091 100644
--- a/taskcluster/ci/toolchain/sysroot.yml
+++ b/taskcluster/ci/toolchain/sysroot.yml
@@ -102,6 +102,27 @@ sysroot-wasm32-wasi-clang-17:
             - linux64-clang-17-stage1
             - wasm32-wasi-compiler-rt-17
 
+sysroot-wasm32-wasi-clang-18:
+    description: "Sysroot for wasi"
+    attributes:
+        local-toolchain: true
+    treeherder:
+        symbol: TL(sysroot-wasi-18)
+    run:
+        script: build-sysroot-wasi.sh
+        arguments:
+            - wasi-sdk.patch
+        resources:
+            - taskcluster/scripts/misc/wasi-sdk.patch
+        toolchain-artifact: public/build/sysroot-wasm32-wasi.tar.zst
+    fetches:
+        fetch:
+            - clang-18
+            - wasi-sdk
+        toolchain:
+            - linux64-clang-18-stage1
+            - wasm32-wasi-compiler-rt-18
+
 sysroot-wasm32-wasi-clang-trunk:
     description: "Sysroot for wasi"
     attributes: