From 2902a1a1bc0c4bfbfe6a5ff2af2de53aaaf444ff Mon Sep 17 00:00:00 2001
From: Aiden Grossman <aidengrossman@google.com>
Date: Wed, 16 Jul 2025 21:48:17 +0000
Subject: [PATCH 1/2] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20ch?=
 =?UTF-8?q?anges=20to=20main=20this=20commit=20is=20based=20on?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Created using spr 1.3.4

[skip ci]
---
 .ci/monolithic-linux.sh                              | 12 ++++--------
 .ci/monolithic-windows.sh                            |  5 -----
 .../workflows/containers/github-action-ci/Dockerfile | 12 ++++++++++--
 3 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/.ci/monolithic-linux.sh b/.ci/monolithic-linux.sh
index 8d1faab13986c..d9f51ba9fd946 100755
--- a/.ci/monolithic-linux.sh
+++ b/.ci/monolithic-linux.sh
@@ -21,12 +21,7 @@ BUILD_DIR="${BUILD_DIR:=${MONOREPO_ROOT}/build}"
 INSTALL_DIR="${BUILD_DIR}/install"
 rm -rf "${BUILD_DIR}"
 
-ccache --zero-stats
-
-if [[ -n "${CLEAR_CACHE:-}" ]]; then
-  echo "clearing cache"
-  ccache --clear
-fi
+sccache --zero-stats
 
 mkdir -p artifacts/reproducers
 
@@ -36,7 +31,7 @@ export CLANG_CRASH_DIAGNOSTICS_DIR=`realpath artifacts/reproducers`
 function at-exit {
   retcode=$?
 
-  ccache --print-stats > artifacts/ccache_stats.txt
+  sccache --show-stats > artifacts/sccache_stats.txt
   cp "${BUILD_DIR}"/.ninja_log artifacts/.ninja_log
   cp "${BUILD_DIR}"/test-results.*.xml artifacts/ || :
 
@@ -78,7 +73,8 @@ cmake -S "${MONOREPO_ROOT}"/llvm -B "${BUILD_DIR}" \
       -D LLVM_LIT_ARGS="${lit_args}" \
       -D LLVM_ENABLE_LLD=ON \
       -D CMAKE_CXX_FLAGS=-gmlt \
-      -D LLVM_CCACHE_BUILD=ON \
+      -D CMAKE_C_COMPILER_LAUNCHER=sccache \
+      -D CMAKE_CXX_COMPILER_LAUNCHER=sccache \
       -D LIBCXX_CXX_ABI=libcxxabi \
       -D MLIR_ENABLE_BINDINGS_PYTHON=ON \
       -D LLDB_ENABLE_PYTHON=ON \
diff --git a/.ci/monolithic-windows.sh b/.ci/monolithic-windows.sh
index 176350fac604c..50a741677d734 100755
--- a/.ci/monolithic-windows.sh
+++ b/.ci/monolithic-windows.sh
@@ -21,11 +21,6 @@ BUILD_DIR="${BUILD_DIR:=${MONOREPO_ROOT}/build}"
 
 rm -rf "${BUILD_DIR}"
 
-if [[ -n "${CLEAR_CACHE:-}" ]]; then
-  echo "clearing sccache"
-  rm -rf "$SCCACHE_DIR"
-fi
-
 sccache --zero-stats
 function at-exit {
   retcode=$?
diff --git a/.github/workflows/containers/github-action-ci/Dockerfile b/.github/workflows/containers/github-action-ci/Dockerfile
index efe08ebc221c5..a8a3428a4471a 100644
--- a/.github/workflows/containers/github-action-ci/Dockerfile
+++ b/.github/workflows/containers/github-action-ci/Dockerfile
@@ -63,11 +63,19 @@ RUN apt-get update && \
     python3-pip \
     ccache \
     file \
-    tzdata \
-    sccache && \
+    tzdata && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
 
+# We need sccache for caching. We cannot use the apt repository version because
+# it is too old and has bugs related to features we require (particularly GCS
+# caching), so we manually install it here.
+RUN curl -L 'https://github.com/mozilla/sccache/releases/download/v0.10.0/sccache-v0.10.0-x86_64-unknown-linux-musl.tar.gz' > /tmp/sccache.tar.gz && \
+    echo "1fbb35e135660d04a2d5e42b59c7874d39b3deb17de56330b25b713ec59f849b /tmp/sccache.tar.gz" | sha256sum -c && \
+    tar xzf /tmp/sccache.tar.gz -O --wildcards '*/sccache' > '/usr/local/bin/sccache' && \
+    rm /tmp/sccache.tar.gz && \
+    chmod +x /usr/local/bin/sccache
+
 ENV LLVM_SYSROOT=$LLVM_SYSROOT
 ENV PATH=${LLVM_SYSROOT}/bin:${PATH}
 

From 7c3030a3b6da3ef8a48acfe0031a7c2ed348499a Mon Sep 17 00:00:00 2001
From: Aiden Grossman <aidengrossman@google.com>
Date: Thu, 17 Jul 2025 14:50:26 +0000
Subject: [PATCH 2/2] feedback

Created using spr 1.3.4
---
 .github/workflows/containers/github-action-ci/Dockerfile | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/.github/workflows/containers/github-action-ci/Dockerfile b/.github/workflows/containers/github-action-ci/Dockerfile
index 74bef3de6dc3c..a4ba956acd501 100644
--- a/.github/workflows/containers/github-action-ci/Dockerfile
+++ b/.github/workflows/containers/github-action-ci/Dockerfile
@@ -58,8 +58,7 @@ RUN apt-get update && \
     python3-psutil \
     sudo \
     # These are needed by the premerge pipeline. Pip is used to install
-    # dependent python packages and sccache is used for build caching. File and
-    # tzdata are used for tests.
+    # dependent python packages. File and tzdata are used for tests.
     python3-pip \
     file \
     tzdata && \