diff --git a/projects/eudsl-llvmpy/CMakeLists.txt b/projects/eudsl-llvmpy/CMakeLists.txt
index b6ba28f7e..ae28f4dd3 100644
--- a/projects/eudsl-llvmpy/CMakeLists.txt
+++ b/projects/eudsl-llvmpy/CMakeLists.txt
@@ -41,7 +41,8 @@ add_definitions(${LLVM_DEFINITIONS})
 # C++ source coverage (llvm-cov). When ON, the extension is built with
 # instrumentation; scripts/cpp_coverage.sh runs the test suite (which imports
 # the .so) under LLVM_PROFILE_FILE, merges the profraw, and enforces a
-# src/IR + src/MIR line-coverage threshold via scripts/check_coverage.py.
+# src/IR + src/MIR line-coverage threshold via the repo-root
+# scripts/check_coverage.py.
 option(EUDSL_LLVMPY_ENABLE_COVERAGE "Instrument eudslllvm_ext for llvm-cov" OFF)
 if(EUDSL_LLVMPY_ENABLE_COVERAGE)
   message(STATUS "EUDSL_LLVMPY: C++ coverage instrumentation enabled")
diff --git a/projects/eudsl-llvmpy/README.md b/projects/eudsl-llvmpy/README.md
index 26827b433..8ae10702d 100644
--- a/projects/eudsl-llvmpy/README.md
+++ b/projects/eudsl-llvmpy/README.md
@@ -268,7 +268,7 @@ Python coverage is gated in `pyproject.toml` (`--cov=llvm`, branch coverage,
 fail under 99%). C++ coverage runs through `scripts/cpp_coverage.sh`, which
 builds the extension instrumented, runs the suite under `LLVM_PROFILE_FILE`,
 merges the profile, and enforces a `src/IR` line-coverage threshold with
-`scripts/check_coverage.py`:
+the repo-root `scripts/check_coverage.py` (shared with other projects):
 
 ```bash
 COVERAGE_THRESHOLD=100 bash scripts/cpp_coverage.sh
diff --git a/projects/eudsl-llvmpy/scripts/cpp_coverage.sh b/projects/eudsl-llvmpy/scripts/cpp_coverage.sh
index 64b5fbb17..36a68cd5a 100755
--- a/projects/eudsl-llvmpy/scripts/cpp_coverage.sh
+++ b/projects/eudsl-llvmpy/scripts/cpp_coverage.sh
@@ -67,7 +67,7 @@ if [[ -z "$SO" || ! -f "$SO" ]]; then
 fi
 
 echo ">> checking src/IR + src/MIR coverage (threshold=${THRESHOLD}%)"
-"$PY" "${PROJ_DIR}/scripts/check_coverage.py" \
+"$PY" "${PROJ_DIR}/../../scripts/check_coverage.py" \
   --llvm-cov "$LLVM_COV" \
   --profdata "${COV_DIR}/eudslllvm.profdata" \
   --objects "$SO" \
diff --git a/projects/eudsl-llvmpy/scripts/check_coverage.py b/scripts/check_coverage.py
similarity index 100%
rename from projects/eudsl-llvmpy/scripts/check_coverage.py
rename to scripts/check_coverage.py
diff --git a/scripts/cmake/llvm_cache.cmake b/scripts/cmake/llvm_cache.cmake
index 45b018a77..15ff57761 100644
--- a/scripts/cmake/llvm_cache.cmake
+++ b/scripts/cmake/llvm_cache.cmake
@@ -9,6 +9,21 @@ include(CMakePrintHelpers)
 
 set(LLVM_ENABLE_PROJECTS "llvm;mlir;clang" CACHE STRING "")
 
+if (NOT WIN32)
+  # compiler-rt builtins only (built by the separate `builtins` sub-build);
+  # every compiler-rt runtime is off.
+  set(LLVM_ENABLE_RUNTIMES "compiler-rt" CACHE STRING "")
+  set(COMPILER_RT_BUILD_BUILTINS ON CACHE BOOL "")
+  foreach(_crt SANITIZERS XRAY LIBFUZZER PROFILE MEMPROF CTX_PROFILE ORC GWP_ASAN)
+    set(COMPILER_RT_BUILD_${_crt} OFF CACHE BOOL "")
+  endforeach()
+  set(COMPILER_RT_INCLUDE_TESTS OFF CACHE BOOL "")
+  # macOS only; avoids needing iOS/watchOS/tvOS/visionOS SDKs.
+  foreach(_os IOS WATCHOS TVOS XROS)
+    set(COMPILER_RT_ENABLE_${_os} OFF CACHE BOOL "")
+  endforeach()
+endif()
+
 # LLVM options
 
 set(LLVM_BUILD_TOOLS ON CACHE BOOL "")
@@ -63,6 +78,7 @@ set(LLVM_ENABLE_CRASH_OVERRIDES OFF CACHE BOOL "")
 set(LLVM_ENABLE_Z3_SOLVER OFF CACHE BOOL "")
 set(LLVM_ENABLE_ZLIB OFF CACHE BOOL "")
 set(LLVM_ENABLE_ZSTD OFF CACHE BOOL "")
+set(LLVM_ENABLE_LZMA OFF CACHE BOOL "")
 set(LLVM_INCLUDE_BENCHMARKS OFF CACHE BOOL "")
 set(LLVM_INCLUDE_DOCS OFF CACHE BOOL "")
 set(LLVM_INCLUDE_EXAMPLES OFF CACHE BOOL "")
@@ -81,9 +97,10 @@ set(MLIR_INCLUDE_TESTS ${RUN_TESTS} CACHE BOOL "")
 set(LLVM_INSTALL_TOOLCHAIN_ONLY OFF CACHE BOOL "")
 
 set(LLVM_DISTRIBUTIONS MlirDevelopment CACHE STRING "")
-set(LLVM_MlirDevelopment_DISTRIBUTION_COMPONENTS
+set(_mlir_dev_components
     clang-libraries
     clang-headers
+    clang-resource-headers
     # triggers ClangConfig.cmake and etc
     clang-cmake-exports
     # triggers ClangMlirDevelopmentTargets.cmake
@@ -118,12 +135,16 @@ set(LLVM_MlirDevelopment_DISTRIBUTION_COMPONENTS
     mlir-reduce
     mlir-tblgen
     mlir-translate
-    CACHE STRING "")
+)
 
 if (NOT WIN32)
-  list(APPEND LLVM_MlirDevelopment_DISTRIBUTION_COMPONENTS LLVM MLIR)
+  list(APPEND _mlir_dev_components LLVM MLIR builtins)
 endif()
 
+# Only cache entries survive a -C script, so the list must be complete before
+# it is cached (appending to the variable afterwards has no effect).
+set(LLVM_MlirDevelopment_DISTRIBUTION_COMPONENTS ${_mlir_dev_components} CACHE STRING "")
+
 get_cmake_property(_variableNames VARIABLES)
 list(SORT _variableNames)
 cmake_print_variables(${_variableNames})