diff --git a/Makefile b/Makefile
index 46f003bf52..40abccd2fc 100644
--- a/Makefile
+++ b/Makefile
@@ -43,7 +43,7 @@ TESTABLE_APPS  := bash coreutils curl git grep lmbench sed tinycc
 APP            ?= $(TESTABLE_APPS)
 
 # -------- Phonies -------------------------------------------------------------
-.PHONY: all preflight dirs print-config check-build libtirpc gnulib zlib openssl libcxx merge-base-sysroot merge-sysroot lmbench bash nginx coreutils cpython git curl grep sed gcc binutils postgres clean clean-all rebuild-libs rebuild-sysroot test install-bash install-nginx install-git install-curl install-grep install-sed install-lmbench install-coreutils install-gcc install-binutils install
+.PHONY: all preflight dirs print-config check-build libtirpc gnulib zlib openssl libcxx merge-base-sysroot merge-sysroot lmbench bash nginx coreutils cpython git curl grep sed gcc binutils clang postgres clean clean-all rebuild-libs rebuild-sysroot install-bash install-nginx install-git install-curl install-grep install-sed install-lmbench install-coreutils install-gcc install-binutils install-clang install
 
 all: preflight libtirpc gnulib merge-sysroot lmbench bash
 
@@ -79,24 +79,20 @@ check-build:
 	done
 
 clean:
-	@if [[ -z "$(strip $(APP))" ]]; then \
-	  echo "ERROR: no apps selected; set APP to one or more of: $(TESTABLE_APPS)"; \
-	  exit 1; \
-	fi
+	@# Per-app clean scripts (optional — skips apps without clean.sh)
 	@for app in $(APP); do \
 	  case " $(TESTABLE_APPS) " in \
 	    *" $$app "*) ;; \
-	    *) echo "ERROR: unsupported clean app '$$app'; supported apps: $(TESTABLE_APPS)"; exit 1 ;; \
+	    *) continue ;; \
 	  esac; \
 	  if [[ -x '$(APPS_ROOT)/'"$$app"'/clean.sh' ]]; then \
 	    '$(APPS_ROOT)/'"$$app"'/clean.sh' "$$app"; \
-	  else \
-	    echo "[SKIP] $$app: missing $(APPS_ROOT)/$$app/clean.sh"; \
 	  fi; \
 	done
+	@# Infrastructure: stamps, sysroot, overlay, toolchain env
 	-rm -rf '$(APPS_OVERLAY)' '$(MERGED_SYSROOT)' '$(APPS_BIN_DIR)' '$(APPS_LIB_DIR)' '$(TOOL_ENV)'
-	-rm -f '$(LIBTIRPC_STAMP)' '$(GNULIB_STAMP)' '$(ZLIB_STAMP)' '$(OPENSSL_STAMP)'
-	-rm -f '$(MERGE_BASE_STAMP)' '$(MERGE_TIRPC_STAMP)' '$(MERGE_GNULIB_STAMP)' '$(MERGE_ZLIB_STAMP)' '$(MERGE_OPENSSL_STAMP)' '$(MERGE_ALL_STAMP)'
+	-rm -f '$(LIBTIRPC_STAMP)' '$(GNULIB_STAMP)' '$(ZLIB_STAMP)' '$(OPENSSL_STAMP)' '$(LIBCXX_STAMP)'
+	-rm -f '$(MERGE_BASE_STAMP)' '$(MERGE_TIRPC_STAMP)' '$(MERGE_GNULIB_STAMP)' '$(MERGE_ZLIB_STAMP)' '$(MERGE_OPENSSL_STAMP)' '$(MERGE_LIBCXX_STAMP)' '$(MERGE_ALL_STAMP)'
 
 print-config:
 	@echo "LIND_WASM_ROOT=$(LIND_WASM_ROOT)"
@@ -329,6 +325,14 @@ binutils: $(MERGE_ZLIB_STAMP)
 	. '$(TOOL_ENV)'
 	JOBS='$(JOBS)' '$(APPS_ROOT)/binutils/compile_binutils.sh'
 
+# ---------------- clang (WASM build) -------------------------------------------
+# Uses llvm-project/compile_clang.sh to cross-compile clang and lld as
+# wasm32-wasi binaries.  Requires libc++ in the merged sysroot (C++ source).
+# Stages artifacts under build/clang/usr/local/bin.
+clang: $(MERGE_LIBCXX_STAMP)
+	. '$(TOOL_ENV)'
+	JOBS='$(JOBS)' '$(APPS_ROOT)/llvm-project/compile_clang.sh'
+
 rebuild-libs:
 	rm -f '$(LIBTIRPC_STAMP)' '$(GNULIB_STAMP)' '$(ZLIB_STAMP)' '$(OPENSSL_STAMP)' '$(LIBCXX_STAMP)' \
 	  '$(MERGE_TIRPC_STAMP)' '$(MERGE_GNULIB_STAMP)' '$(MERGE_ZLIB_STAMP)' '$(MERGE_OPENSSL_STAMP)' '$(MERGE_LIBCXX_STAMP)' '$(MERGE_ALL_STAMP)'
@@ -376,4 +380,7 @@ install-gcc:
 install-binutils:
 	'$(APPS_ROOT)/scripts/post_install.sh' '$(LINDFS_ROOT)' '$(APPS_BUILD)' binutils
 
-install: install-bash install-nginx install-git install-curl install-grep install-sed install-lmbench install-coreutils install-gcc install-binutils
+install-clang:
+	'$(APPS_ROOT)/scripts/post_install.sh' '$(LINDFS_ROOT)' '$(APPS_BUILD)' clang
+
+install: install-bash install-nginx install-git install-curl install-grep install-sed install-lmbench install-coreutils install-gcc install-binutils install-clang
diff --git a/llvm-project/Toolchain-WASI-LLVM.cmake.in b/llvm-project/Toolchain-WASI-LLVM.cmake.in
new file mode 100644
index 0000000000..abfd647a1f
--- /dev/null
+++ b/llvm-project/Toolchain-WASI-LLVM.cmake.in
@@ -0,0 +1,56 @@
+# Auto-generated CMake toolchain for cross-compiling LLVM to wasm32-wasi
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR wasm32)
+
+# Compiler and tools
+set(CMAKE_C_COMPILER "@CLANG@")
+set(CMAKE_CXX_COMPILER "@CLANGXX@")
+set(CMAKE_AR "@AR@")
+set(CMAKE_NM "@NM@")
+set(CMAKE_RANLIB "@RANLIB@")
+set(CMAKE_SYSROOT "@BASE_SYSROOT@")
+set(CMAKE_LINKER "@LD@")
+
+# Target configuration
+set(CMAKE_C_COMPILER_TARGET wasm32-unknown-wasi)
+set(CMAKE_CXX_COMPILER_TARGET wasm32-unknown-wasi)
+
+# Force CMake to accept compilers without try-run (can't run wasm on host)
+set(CMAKE_C_COMPILER_WORKS TRUE)
+set(CMAKE_CXX_COMPILER_WORKS TRUE)
+set(CMAKE_EXECUTABLE_SUFFIX ".wasm")
+
+# WASM C flags — use -Os to minimize binary size (clang is huge)
+# Use CACHE FORCE so nothing can override these (not even a stale CMakeCache)
+# WASI uses glibc headers — define __linux__ so LLVM uses <endian.h>,
+# Linux-style struct fields, etc.  (WASI is not Linux, but its glibc
+# sysroot matches the Linux ABI for these purposes.)
+set(CMAKE_C_FLAGS "-Os -pthread -matomics -mbulk-memory -fno-exceptions -fno-unwind-tables -D__linux__" CACHE STRING "" FORCE)
+
+# WASM C++ flags — use libc++, no exceptions/RTTI/unwind to reduce binary size
+set(CMAKE_CXX_FLAGS "-Os -pthread -matomics -mbulk-memory -fno-exceptions -fno-unwind-tables -fno-rtti -D__linux__ -nostdinc++ -isystem $LIBCXX_INCLUDE -include $SCRIPT_DIR/fix_std_maxmin.h" CACHE STRING "" FORCE)
+
+# Linker flags
+set(CMAKE_EXE_LINKER_FLAGS "\
+  -L$MERGED_SYSROOT/lib/wasm32-wasi \
+  -L$MERGED_SYSROOT/usr/lib/wasm32-wasi \
+  -Wl,--export=__stack_pointer,--export=__stack_low \
+  -Wl,--import-memory,--export-memory \
+  -Wl,--max-memory=67108864 \
+  -lm " CACHE STRING "" FORCE)
+
+# Don't pass -rpath to the linker
+set(CMAKE_SKIP_RPATH TRUE)
+set(CMAKE_SKIP_INSTALL_RPATH TRUE)
+set(CMAKE_BUILD_WITH_INSTALL_RPATH FALSE)
+set(CMAKE_INSTALL_RPATH_USE_LINK_PATH FALSE)
+
+# Prevent try-run errors
+set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
+
+# Skip old toolchain warnings
+set(LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN ON CACHE BOOL "" FORCE)
+
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
diff --git a/llvm-project/compile_clang.sh b/llvm-project/compile_clang.sh
new file mode 100755
index 0000000000..582af64bc2
--- /dev/null
+++ b/llvm-project/compile_clang.sh
@@ -0,0 +1,368 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+###############################################################################
+# Clang/LLD WASI build helper for lind-wasm-apps
+#
+# Cross-compiles LLVM 18.1.8 (clang + lld) to wasm32-wasi so that the
+# compiler and linker can run inside the Lind sandbox.  The resulting tools
+# target x86_64-unknown-linux-gnu (X86 backend only).
+#
+# High-level strategy:
+#   1. Build native LLVM tools (llvm-tblgen, clang-tblgen, etc.) — required
+#      because CMake can't run wasm binaries during the build
+#   2. Generate CMake toolchain file for wasm32-wasi cross-compilation
+#   3. Configure cross-build with CMake
+#   4. Build clang and lld
+#   5. Post-process each binary: wasm-opt (asyncify) + lind-boot (precompile)
+#
+# Based on Alice's work on the alice-clang branch in lind-wasm.
+#
+# Prerequisites:
+#   - Run 'make preflight' and ensure libc++ is in the merged sysroot
+#     (run 'make libcxx merge-sysroot' or let the Makefile handle it)
+#   - cmake >= 3.20 and ninja (or make) must be on PATH
+###############################################################################
+
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+APPS_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+LLVM_SRC="$SCRIPT_DIR/llvm"
+
+APPS_BUILD="$APPS_ROOT/build"
+MERGED_SYSROOT="$APPS_BUILD/sysroot_merged"
+STAGE_DIR="$APPS_BUILD/clang/usr/local/bin"
+TOOL_ENV="$APPS_BUILD/.toolchain.env"
+
+if [[ -z "${LIND_WASM_ROOT:-}" ]]; then
+  LIND_WASM_ROOT="$(cd "$APPS_ROOT/.." && pwd)"
+fi
+
+WASM_OPT="${WASM_OPT:-$LIND_WASM_ROOT/tools/binaryen/bin/wasm-opt}"
+LIND_BOOT="${LIND_BOOT:-$LIND_WASM_ROOT/build/lind-boot}"
+
+JOBS="${JOBS:-$(nproc 2>/dev/null || getconf _NPROCESSORS_ONLN || echo 4)}"
+CMAKE="${CMAKE:-cmake}"
+
+# ----------------------------------------------------------------------
+# 1) Load toolchain from Makefile preflight
+# ----------------------------------------------------------------------
+if [[ -r "$TOOL_ENV" ]]; then
+  # shellcheck disable=SC1090
+  . "$TOOL_ENV"
+else
+  echo "[clang] ERROR: missing toolchain env '$TOOL_ENV' (run 'make preflight' first)" >&2
+  exit 1
+fi
+
+: "${CLANG:?missing CLANG in $TOOL_ENV}"
+: "${AR:?missing AR in $TOOL_ENV}"
+: "${RANLIB:?missing RANLIB in $TOOL_ENV}"
+: "${NM:?missing NM in $TOOL_ENV}"
+
+LLVM_BIN_DIR="$(dirname "$CLANG")"
+CLANGXX="$LLVM_BIN_DIR/clang++"
+if [[ ! -x "$CLANGXX" ]]; then
+  echo "[clang] WARN: clang++ not found; creating symlink to clang"
+  ln -sf "$CLANG" "$CLANGXX"
+fi
+
+# Sanity checks
+if [[ ! -d "$LLVM_SRC" ]]; then
+  echo "[clang] ERROR: LLVM source dir not found at '$LLVM_SRC'" >&2
+  exit 1
+fi
+if [[ ! -d "$SCRIPT_DIR/clang" ]]; then
+  echo "[clang] ERROR: clang source dir not found at '$SCRIPT_DIR/clang'" >&2
+  exit 1
+fi
+if [[ ! -d "$MERGED_SYSROOT" ]]; then
+  echo "[clang] ERROR: merged sysroot '$MERGED_SYSROOT' not found. Run 'make merge-sysroot' first." >&2
+  exit 1
+fi
+if [[ ! -f "$MERGED_SYSROOT/lib/wasm32-wasi/libc++.a" ]]; then
+  echo "[clang] ERROR: libc++.a not found in merged sysroot. Run 'make libcxx merge-sysroot' first." >&2
+  exit 1
+fi
+if ! command -v "$CMAKE" &>/dev/null; then
+  echo "[clang] ERROR: cmake not found on PATH" >&2
+  exit 1
+fi
+
+mkdir -p "$STAGE_DIR"
+
+LIBCXX_INCLUDE="$MERGED_SYSROOT/include/wasm32-wasi/c++/v1"
+
+echo "[clang] using CLANG          = $CLANG"
+echo "[clang] using CLANGXX        = $CLANGXX"
+echo "[clang] using AR             = $AR"
+echo "[clang] using LD             = $LD"
+echo "[clang] LIND_WASM_ROOT       = $LIND_WASM_ROOT"
+echo "[clang] merged sysroot       = $MERGED_SYSROOT"
+echo "[clang] libc++ headers       = $LIBCXX_INCLUDE"
+echo "[clang] stage dir            = $STAGE_DIR"
+echo
+
+# ----------------------------------------------------------------------
+# 2) Build native LLVM tools (tablegen etc.)
+#
+# CMake cannot run wasm binaries during the build, so we need native
+# versions of llvm-tblgen, clang-tblgen, llvm-min-tblgen, and
+# clang-tidy-confusable-chars-gen for the cross-build.
+# ----------------------------------------------------------------------
+NATIVE_BUILD="$APPS_BUILD/llvm-native-build"
+
+if [[ ! -x "$NATIVE_BUILD/bin/llvm-tblgen" ]] || \
+   [[ ! -x "$NATIVE_BUILD/bin/clang-tblgen" ]]; then
+  echo "[clang] building native LLVM tools (tablegen etc.)…"
+  mkdir -p "$NATIVE_BUILD"
+
+  "$CMAKE" -B "$NATIVE_BUILD" -S "$LLVM_SRC" \
+    -DCMAKE_BUILD_TYPE=Release \
+    -DLLVM_ENABLE_PROJECTS="clang;lld" \
+    -DLLVM_INCLUDE_TESTS=OFF \
+    -DLLVM_BUILD_TESTS=OFF \
+    -DLLVM_INCLUDE_BENCHMARKS=OFF \
+    -DLLVM_INCLUDE_EXAMPLES=OFF \
+    -DLLVM_TARGETS_TO_BUILD="X86"
+
+  "$CMAKE" --build "$NATIVE_BUILD" --target \
+    llvm-tblgen clang-tblgen llvm-min-tblgen \
+    -j"$JOBS"
+
+  echo "[clang] native tools built at $NATIVE_BUILD/bin/"
+else
+  echo "[clang] native LLVM tools already built; skipping."
+fi
+
+# ----------------------------------------------------------------------
+# 3) Build compiler-rt
+# ----------------------------------------------------------------------
+echo "[clang] building compiler-rt…"
+
+"$SCRIPT_DIR/compile_compiler-rt.sh"
+
+# ----------------------------------------------------------------------
+# 4) Generate CMake toolchain file for wasm32-wasi cross-compilation
+# ----------------------------------------------------------------------
+mkdir -p "$BUILD_DIR"
+
+TOOLCHAIN_FILE="$BUILD_DIR/Toolchain-WASI-LLVM.cmake"
+sed -e "s|@CLANG@|$CLANG|g" \
+    -e "s|@CLANGXX@|$CLANGXX|g" \
+    -e "s|@AR@|$AR|g" \
+    -e "s|@NM@|$NM|g" \
+    -e "s|@LD@|$LD|g" \
+    -e "s|@RANLIB@|$RANLIB|g" \
+    -e "s|@BASE_SYSROOT@|$BASE_SYSROOT|g" \
+    "$SCRIPT_DIR/Toolchain-WASI.cmake.in" > "$TOOLCHAIN_FILE"
+
+echo "[clang] generated toolchain file: $TOOLCHAIN_FILE"
+
+# ----------------------------------------------------------------------
+# 5) Configure cross-build
+# ----------------------------------------------------------------------
+echo "[clang] configuring cross-build…"
+
+"$CMAKE" -B "$CROSS_BUILD" -S "$LLVM_SRC" \
+  -DCMAKE_TOOLCHAIN_FILE="$TOOLCHAIN_FILE" \
+  -DCMAKE_BUILD_TYPE=Release \
+  -DLLVM_ENABLE_PROJECTS="clang;lld" \
+  -DLLVM_HOST_TRIPLE="wasm32-unknown-wasi" \
+  -DLLVM_DEFAULT_TARGET_TRIPLE="x86_64-unknown-linux-gnu" \
+  -DLLVM_TARGETS_TO_BUILD="X86" \
+  -DLLVM_NATIVE_TOOL_DIR="$NATIVE_BUILD/bin" \
+  -DLLVM_ENABLE_THREADS=OFF \
+  -DLLVM_ENABLE_PIC=OFF \
+  -DLLVM_ENABLE_LIBCXX=ON \
+  -DLLVM_BUILD_SHARED_LIBS=OFF \
+  -DLLVM_BUILD_TOOLS=OFF \
+  -DLLVM_BUILD_TESTS=OFF \
+  -DLLVM_INCLUDE_TESTS=OFF \
+  -DLLVM_INCLUDE_EXAMPLES=OFF \
+  -DLLVM_INCLUDE_BENCHMARKS=OFF \
+  -DLLVM_INCLUDE_GOOGLETEST=OFF \
+  -DLLVM_TOOL_CLANG_BUILD=ON \
+  -DLLVM_TOOL_LLD_BUILD=ON \
+  -DLLVM_TOOL_LLI_BUILD=OFF \
+  -DLLVM_TOOL_LLVM_JITLINK_EXECUTOR_BUILD=OFF \
+  -DLLD_ENABLE_TARGETS="ELF" \
+  -DCLANG_INCLUDE_TESTS=OFF \
+  -DLLD_INCLUDE_TESTS=OFF \
+  -DCMAKE_SKIP_RPATH=ON \
+  -DCMAKE_SKIP_INSTALL_RPATH=ON \
+  -DCMAKE_C_STANDARD_LIBRARIES="-lc -lcompiler_rt" \
+  -DCMAKE_CXX_STANDARD_LIBRARIES="-lc++ -lc++abi -lc -lcompiler_rt" \
+  -DHAVE_LIBRT=0 \
+  -DHAVE_LIBATOMIC=1 \
+  -DHAVE_CXX_ATOMICS_WITHOUT_LIB=ON \
+  -DHAVE_CXX_ATOMICS64_WITHOUT_LIB=ON \
+  -DHAVE_CXX_ATOMICS_WITH_LIB=OFF \
+  -DHAVE_CXX_ATOMICS64_WITH_LIB=OFF
+
+# ----------------------------------------------------------------------
+# 6) Build clang and lld
+# ----------------------------------------------------------------------
+echo "[clang] building clang…"
+"$CMAKE" --build "$CROSS_BUILD" --target clang -j"$JOBS"
+
+echo "[clang] building lld…"
+"$CMAKE" --build "$CROSS_BUILD" --target lld -j"$JOBS"
+
+echo "[clang] installing core resource headers…"
+"$CMAKE" --build "$CROSS_BUILD" --target install-core-resource-headers -j"$JOBS"
+
+# ----------------------------------------------------------------------
+# 7) Post-processing helper
+# ----------------------------------------------------------------------
+post_process_binary() {
+  local NAME="$1"
+  local SRC_BIN="$2"
+  local USE_OS="${3:-false}"  # use -Os instead of -O2
+
+  if [[ ! -f "$SRC_BIN" ]]; then
+    echo "[clang] ERROR: $NAME binary not produced at '$SRC_BIN'" >&2
+    return 1
+  fi
+
+  local WASM_FILE="$SCRIPT_DIR/${NAME}.wasm"
+  local OPT_WASM="$SCRIPT_DIR/${NAME}.opt.wasm"
+  cp "$SRC_BIN" "$WASM_FILE"
+  echo "[clang] $NAME binary size: $(du -h "$WASM_FILE" | cut -f1)"
+
+  # --- wasm-opt ---
+  if [[ ! -x "$WASM_OPT" ]]; then
+    echo "[clang] ERROR: wasm-opt not found at '$WASM_OPT'; exiting." >&2
+    exit 1
+  fi
+
+  local OPT_FLAGS=()
+  if [[ "$USE_OS" == "true" ]]; then
+    OPT_FLAGS+=(-Os)
+  else
+    OPT_FLAGS+=(-O2)
+  fi
+
+  # Build asyncify removelist for this binary
+  local ASYNCIFY_IGNORE="$SCRIPT_DIR/${NAME}_asyncify_ignore.txt"
+  generate_asyncify_ignorelist "$NAME" "$ASYNCIFY_IGNORE"
+  local IGNORE_COUNT
+  IGNORE_COUNT=$(wc -l < "$ASYNCIFY_IGNORE")
+  echo "[clang] asyncify removelist for $NAME: $IGNORE_COUNT wildcard patterns"
+
+  echo "[clang] running wasm-opt on $NAME (epoch-injection + asyncify + ${OPT_FLAGS[*]})…"
+  "$WASM_OPT" --epoch-injection --asyncify \
+    --pass-arg=asyncify-removelist@@"$ASYNCIFY_IGNORE" \
+    --debuginfo "${OPT_FLAGS[@]}" \
+    "$WASM_FILE" -o "$OPT_WASM"
+
+  if [[ ! -f "$OPT_WASM" ]]; then
+    echo "[clang] ERROR: failed to generate '$OPT_WASM'; exiting." >&2
+    exit 1
+  fi
+
+  # --- lind-boot --precompile ---
+  if [[ ! -x "$LIND_BOOT" ]]; then
+    echo "[clang] ERROR: lind-boot not found at '$LIND_BOOT'" >&2
+    exit 1
+  fi
+
+  echo "[clang] generating cwasm for $NAME via lind-boot --precompile…"
+  "$LIND_BOOT" --precompile "$OPT_WASM"
+
+  local OPT_CWASM="$SCRIPT_DIR/${NAME}.opt.cwasm"
+  if [[ ! -f "$OPT_CWASM" ]]; then
+    echo "[clang] ERROR: precompile produced no .cwasm for $NAME" >&2
+    exit 1
+  fi
+
+  cp "$OPT_CWASM" "$STAGE_DIR/$NAME"
+  echo "[clang] $NAME staged as $STAGE_DIR/$NAME (precompiled)"
+}
+
+# ----------------------------------------------------------------------
+# 8) Asyncify ignore list generator
+#
+# Like GCC's cc1, clang is a massive C++ binary with auto-generated
+# code (TableGen instruction selection, pattern matchers) and
+# template-heavy libraries that explode under asyncify.  These are
+# all pure computation with no I/O or yield points.
+# ----------------------------------------------------------------------
+generate_asyncify_ignorelist() {
+  local NAME="$1"
+  local OUTFILE="$2"
+
+  # The WASM name section contains a mix of demangled C++ names and
+  # mangled _Z* names.  All C++ functions in clang/LLVM are pure
+  # computation — I/O only happens through C runtime functions (glibc
+  # wrappers like __lind_make_syscall, read, write, etc.) which don't
+  # have C++ mangled names.
+  #
+  # Exclude ALL C++ functions from asyncify.  This is safe because:
+  #   - Asyncify only needs to instrument functions that transitively
+  #     reach yield points (I/O syscalls)
+  #   - All yield points go through C runtime stubs (no _Z prefix,
+  #     no C++ demangled names with ::)
+  #   - The C stubs are small and asyncify handles them fine
+  #
+  # We match both mangled (_Z*) and demangled (*::*) C++ names,
+  # plus common LLVM/Clang class names as a safety net.
+  cat > "$OUTFILE" << 'PATTERNS'
+_Z*
+*::*
+*(anonymous namespace)*
+PATTERNS
+}
+
+# ----------------------------------------------------------------------
+# 9) Locate and post-process binaries
+# ----------------------------------------------------------------------
+# clang binary — CMake produces bin/clang-18.wasm (or similar)
+CLANG_BIN=""
+for candidate in \
+  "$CROSS_BUILD/bin/clang-18.wasm" \
+  "$CROSS_BUILD/bin/clang-18" \
+  "$CROSS_BUILD/bin/clang.wasm" \
+  "$CROSS_BUILD/bin/clang"; do
+  if [[ -f "$candidate" ]]; then
+    CLANG_BIN="$candidate"
+    break
+  fi
+done
+
+if [[ -z "$CLANG_BIN" ]]; then
+  echo "[clang] ERROR: clang binary not found in $CROSS_BUILD/bin/" >&2
+  echo "[clang] Contents of $CROSS_BUILD/bin/:"
+  ls -la "$CROSS_BUILD/bin/" || true
+  exit 1
+fi
+
+# lld binary
+LLD_BIN=""
+for candidate in \
+  "$CROSS_BUILD/bin/lld.wasm" \
+  "$CROSS_BUILD/bin/lld"; do
+  if [[ -f "$candidate" ]]; then
+    LLD_BIN="$candidate"
+    break
+  fi
+done
+
+if [[ -z "$LLD_BIN" ]]; then
+  echo "[clang] ERROR: lld binary not found in $CROSS_BUILD/bin/" >&2
+  echo "[clang] Contents of $CROSS_BUILD/bin/:"
+  ls -la "$CROSS_BUILD/bin/" || true
+  exit 1
+fi
+
+echo "[clang] found clang at: $CLANG_BIN"
+echo "[clang] found lld at:   $LLD_BIN"
+
+# clang is enormous — use -Os like GCC's cc1
+post_process_binary "clang" "$CLANG_BIN" "true"
+# lld is smaller — -Os is still safer
+post_process_binary "lld"   "$LLD_BIN"   "true"
+
+echo
+echo "[clang] build complete. Outputs under:"
+echo "  $STAGE_DIR"
+ls -lh "$STAGE_DIR" || true
diff --git a/llvm-project/compile_compiler-rt.sh b/llvm-project/compile_compiler-rt.sh
new file mode 100755
index 0000000000..d97946437c
--- /dev/null
+++ b/llvm-project/compile_compiler-rt.sh
@@ -0,0 +1,142 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+###############################################################################
+# compiler-rt WASI build helper for lind-wasm-apps
+#
+# Cross-compiles LLVM compiler-rt builtins to wasm32-wasi using the toolchain
+# detected by the top-level Makefile preflight target. Installs static runtime
+# libraries to the sysroot overlay so merge-sysroot can pick them up.
+#
+# Prerequisites:
+#   - Run 'make preflight' first
+#   - cmake >= 3.20 must be on PATH
+###############################################################################
+
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+APPS_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+LLVM_SRC="$SCRIPT_DIR"
+
+APPS_BUILD="$APPS_ROOT/build"
+APPS_OVERLAY="$APPS_BUILD/sysroot_overlay"
+TOOL_ENV="$APPS_BUILD/.toolchain.env"
+
+if [[ -z "${LIND_WASM_ROOT:-}" ]]; then
+  LIND_WASM_ROOT="$(cd "$APPS_ROOT/.." && pwd)"
+fi
+
+BASE_SYSROOT="${BASE_SYSROOT:-$LIND_WASM_ROOT/src/glibc/sysroot}"
+JOBS="${JOBS:-$(nproc 2>/dev/null || getconf _NPROCESSORS_ONLN || echo 4)}"
+
+# ----------------------------------------------------------------------
+# 1) Load toolchain from Makefile preflight
+# ----------------------------------------------------------------------
+if [[ -r "$TOOL_ENV" ]]; then
+  # shellcheck disable=SC1090
+  . "$TOOL_ENV"
+else
+  echo "[compiler-rt] ERROR: missing toolchain env '$TOOL_ENV' (run 'make preflight' first)" >&2
+  exit 1
+fi
+
+: "${CLANG:?missing CLANG in $TOOL_ENV}"
+: "${AR:?missing AR in $TOOL_ENV}"
+: "${RANLIB:?missing RANLIB in $TOOL_ENV}"
+: "${NM:?missing NM in $TOOL_ENV}"
+
+LLVM_BIN_DIR="$(dirname "$CLANG")"
+CLANGXX="$LLVM_BIN_DIR/clang++"
+if [[ ! -x "$CLANGXX" ]]; then
+  echo "[compiler-rt] WARN: clang++ not found at '$CLANGXX'; creating symlink to clang"
+  ln -sf "$CLANG" "$CLANGXX"
+fi
+
+# Sanity checks
+if [[ ! -d "$LLVM_SRC/compiler-rt" ]]; then
+  echo "[compiler-rt] ERROR: compiler-rt source not found at '$LLVM_SRC/compiler-rt'" >&2
+  exit 1
+fi
+
+if [[ ! -r "$BASE_SYSROOT/include/wasm32-wasi/stdio.h" ]]; then
+  echo "[compiler-rt] ERROR: base sysroot headers missing at '$BASE_SYSROOT'" >&2
+  exit 1
+fi
+
+CMAKE="${CMAKE:-cmake}"
+if ! command -v "$CMAKE" &>/dev/null; then
+  echo "[compiler-rt] ERROR: cmake not found on PATH" >&2
+  exit 1
+fi
+
+BUILD_DIR="$APPS_BUILD/compiler-rt-build"
+INSTALL_DIR="$APPS_BUILD/compiler-rt-install"
+
+echo "[compiler-rt] using CLANG       = $CLANG"
+echo "[compiler-rt] using CLANGXX     = $CLANGXX"
+echo "[compiler-rt] using AR          = $AR"
+echo "[compiler-rt] using NM          = $NM"
+echo "[compiler-rt] using RANLIB      = $RANLIB"
+echo "[compiler-rt] LIND_WASM_ROOT    = $LIND_WASM_ROOT"
+echo "[compiler-rt] base sysroot      = $BASE_SYSROOT"
+echo "[compiler-rt] build dir         = $BUILD_DIR"
+echo "[compiler-rt] install dir       = $INSTALL_DIR"
+echo
+
+mkdir -p "$BUILD_DIR"
+
+# ----------------------------------------------------------------------
+# 2) Generate CMake toolchain file for wasm32-wasi cross-compilation
+# ----------------------------------------------------------------------
+TOOLCHAIN_FILE="$BUILD_DIR/Toolchain-WASI.cmake"
+sed -e "s|@CLANG@|$CLANG|g" \
+    -e "s|@CLANGXX@|$CLANGXX|g" \
+    -e "s|@AR@|$AR|g" \
+    -e "s|@NM@|$NM|g" \
+    -e "s|@RANLIB@|$RANLIB|g" \
+    -e "s|@BASE_SYSROOT@|$BASE_SYSROOT|g" \
+    "$SCRIPT_DIR/Toolchain-WASI.cmake.in" > "$TOOLCHAIN_FILE"
+
+echo "[compiler-rt] generated toolchain file: $TOOLCHAIN_FILE"
+
+# ----------------------------------------------------------------------
+# 3) Configure with CMake
+# ----------------------------------------------------------------------
+echo "[compiler-rt] configuring…"
+
+"$CMAKE" -B "$BUILD_DIR" -S "$LLVM_SRC/compiler-rt" \
+  -G Ninja \
+  -DCMAKE_TOOLCHAIN_FILE="$TOOLCHAIN_FILE" \
+  -DCMAKE_BUILD_TYPE=Release \
+  -DCMAKE_INSTALL_PREFIX="$INSTALL_DIR" \
+  -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY \
+  -DCMAKE_C_COMPILER_WORKS=1 \
+  -DCMAKE_CXX_COMPILER_WORKS=1 \
+  -DCOMPILER_RT_BUILD_BUILTINS=ON \
+  -DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON \
+  -DCOMPILER_RT_INCLUDE_TESTS=OFF \
+  -DCOMPILER_RT_BUILD_SANITIZERS=OFF \
+  -DCOMPILER_RT_BUILD_XRAY=OFF \
+  -DCOMPILER_RT_BUILD_LIBFUZZER=OFF \
+  -DCOMPILER_RT_BUILD_PROFILE=OFF \
+  -DCOMPILER_RT_BUILD_MEMPROF=OFF
+
+# ----------------------------------------------------------------------
+# 4) Build and install
+# ----------------------------------------------------------------------
+echo "[compiler-rt] building…"
+"$CMAKE" --build "$BUILD_DIR" --target install -j"$JOBS"
+
+# ----------------------------------------------------------------------
+# 5) Copy libraries to sysroot overlay
+# ----------------------------------------------------------------------
+echo "[compiler-rt] installing to sysroot overlay…"
+
+mkdir -p "$APPS_OVERLAY/usr/lib/wasm32-wasi"
+
+find "$INSTALL_DIR" -type f \( -name 'libclang_rt.builtins*.a' -o -name 'libcompiler_rt*.a' \) \
+  -exec cp -v {} "$APPS_OVERLAY/usr/lib/wasm32-wasi/" \;
+
+echo
+echo "[compiler-rt] build complete. Outputs:"
+echo "  libs: $APPS_OVERLAY/usr/lib/wasm32-wasi/"
+ls -lh "$APPS_OVERLAY/usr/lib/wasm32-wasi/" | grep -E 'clang_rt|compiler_rt' || true
diff --git a/llvm-project/fix_std_maxmin.h b/llvm-project/fix_std_maxmin.h
new file mode 100644
index 0000000000..1cbea48f69
--- /dev/null
+++ b/llvm-project/fix_std_maxmin.h
@@ -0,0 +1,45 @@
+#ifndef FIX_STD_MAXMIN_H
+#define FIX_STD_MAXMIN_H
+
+// Workaround for wasm32 where size_type (unsigned int) and size_t
+// (unsigned long) are different C++ types but the same width (32-bit).
+// std::min/std::max template deduction fails because it can't unify
+// the two types into a single _Tp.  This doesn't happen on x86_64
+// where size_t = unsigned long (64-bit) and size_type = size_t.
+//
+// Fix: provide mixed-type overloads that use std::common_type to
+// resolve the return type.  The !is_same<T,U> SFINAE guard ensures
+// these only activate when the standard single-type overloads can't
+// deduce, avoiding ambiguity.
+//
+// Force-included via -include before all other headers.
+
+#include <type_traits>
+
+namespace std {
+
+template <typename T, typename U,
+          typename = typename enable_if<
+              is_arithmetic<T>::value && is_arithmetic<U>::value &&
+              !is_same<T, U>::value>::type>
+inline constexpr typename common_type<T, U>::type
+min(const T& a, const U& b) {
+    using CT = typename common_type<T, U>::type;
+    return static_cast<CT>(b) < static_cast<CT>(a)
+        ? static_cast<CT>(b) : static_cast<CT>(a);
+}
+
+template <typename T, typename U,
+          typename = typename enable_if<
+              is_arithmetic<T>::value && is_arithmetic<U>::value &&
+              !is_same<T, U>::value>::type>
+inline constexpr typename common_type<T, U>::type
+max(const T& a, const U& b) {
+    using CT = typename common_type<T, U>::type;
+    return static_cast<CT>(a) < static_cast<CT>(b)
+        ? static_cast<CT>(b) : static_cast<CT>(a);
+}
+
+} // namespace std
+
+#endif // FIX_STD_MAXMIN_H