test: Clang incremental and BMI cache E2E tests

tests/e2e/39_llvm_incremental.sh

@@ -0,0 +1,65 @@
+#!/usr/bin/env bash
+# 39_llvm_incremental.sh — Clang per-file incremental rebuild via clang-scan-deps dyndep.
+set -e
+
+LLVM_ROOT="${HOME}/.mcpp/registry/data/xpkgs/xim-x-llvm/20.1.7"
+if [[ ! -x "$LLVM_ROOT/bin/clang++" ]]; then
+    echo "SKIP: xlings llvm@20.1.7 is not installed"
+    exit 0
+fi
+if [[ ! -f "$LLVM_ROOT/share/libc++/v1/std.cppm" ]]; then
+    echo "SKIP: xlings llvm@20.1.7 has no libc++ std.cppm"
+    exit 0
+fi
+
+TMP=$(mktemp -d)
+trap "rm -rf $TMP" EXIT
+export MCPP_HOME="$TMP/mcpp-home"
+source "$(dirname "$0")/_inherit_toolchain.sh"
+
+mkdir -p "$TMP/proj/src"
+cd "$TMP/proj"
+
+cat > mcpp.toml <<'EOF'
+[package]
+name    = "llvm_inc"
+version = "0.1.0"
+[toolchain]
+linux = "llvm@20.1.7"
+EOF
+
+cat > src/greet.cppm <<'EOF'
+export module llvm_inc.greet;
+import std;
+export std::string greet() { return "hello"; }
+EOF
+
+cat > src/main.cpp <<'EOF'
+import std;
+import llvm_inc.greet;
+int main() { std::println("{}", greet()); }
+EOF
+
+# First build (full)
+"$MCPP" build --no-cache > /dev/null 2>&1
+
+# Second build (no-op) should be fast
+out=$("$MCPP" build 2>&1)
+[[ "$out" == *"Finished"* ]] || { echo "FAIL: no-op rebuild failed: $out"; exit 1; }
+
+# Touch greet.cppm only; rebuild should NOT recompile main.cpp
+sleep 1
+touch src/greet.cppm
+out=$("$MCPP" build --verbose 2>&1)
+echo "$out" | grep -q "greet.cppm" || { echo "FAIL: greet.cppm not rebuilt: $out"; exit 1; }
+# main.cpp should NOT appear in ninja output (it wasn't touched)
+if echo "$out" | grep -q "MOD obj/main.o\|OBJ obj/main.o"; then
+    # Note: main.o MAY be relinked but should NOT be recompiled from source
+    # Check specifically for compilation (not linking)
+    if echo "$out" | grep -q "\-c.*main.cpp"; then
+        echo "FAIL: main.cpp was recompiled when only greet.cppm changed"
+        exit 1
+    fi
+fi
+
+echo "OK"

tests/e2e/40_llvm_bmi_cache.sh

@@ -0,0 +1,69 @@
+#!/usr/bin/env bash
+# 40_llvm_bmi_cache.sh — Clang BMI cache reuse for dependency packages.
+set -e
+
+LLVM_ROOT="${HOME}/.mcpp/registry/data/xpkgs/xim-x-llvm/20.1.7"
+if [[ ! -x "$LLVM_ROOT/bin/clang++" ]]; then
+    echo "SKIP: xlings llvm@20.1.7 is not installed"
+    exit 0
+fi
+if [[ ! -f "$LLVM_ROOT/share/libc++/v1/std.cppm" ]]; then
+    echo "SKIP: xlings llvm@20.1.7 has no libc++ std.cppm"
+    exit 0
+fi
+
+TMP=$(mktemp -d)
+trap "rm -rf $TMP" EXIT
+export MCPP_HOME="$TMP/mcpp-home"
+source "$(dirname "$0")/_inherit_toolchain.sh"
+
+# mcpplibs packages live in a separate registry namespace; inherit it so the
+# index lookup for mcpplibs.cmdline succeeds in the isolated MCPP_HOME.
+USER_MCPP="${HOME}/.mcpp"
+if [[ -d "$USER_MCPP/registry/data/mcpplibs" ]]; then
+    mkdir -p "$MCPP_HOME/registry/data"
+    [[ -e "$MCPP_HOME/registry/data/mcpplibs" ]] \
+        || ln -sf "$USER_MCPP/registry/data/mcpplibs" "$MCPP_HOME/registry/data/mcpplibs"
+fi
+
+mkdir -p "$TMP/proj/src"
+cd "$TMP/proj"
+
+cat > mcpp.toml <<'EOF'
+[package]
+name    = "llvm_cache"
+version = "0.1.0"
+[toolchain]
+linux = "llvm@20.1.7"
+[dependencies]
+"mcpplibs.cmdline" = "0.0.1"
+EOF
+
+cat > src/main.cpp <<'EOF'
+import std;
+import mcpplibs.cmdline;
+int main() {
+    std::println("cache test ok");
+    return 0;
+}
+EOF
+
+# First build — should compile the dependency
+out1=$("$MCPP" build --no-cache 2>&1)
+echo "$out1" | grep -q "Compiling.*mcpplibs.cmdline" || {
+    # It's OK if it says "Cached" because global cache may exist
+    echo "$out1" | grep -q "Cached.*mcpplibs.cmdline" || {
+        echo "FAIL: mcpplibs.cmdline not mentioned in first build: $out1"
+        exit 1
+    }
+}
+
+# Second build (clean target, keep BMI cache) — dependency should be cached
+rm -rf target
+out2=$("$MCPP" build 2>&1)
+echo "$out2" | grep -q "Cached.*mcpplibs.cmdline" || {
+    echo "FAIL: mcpplibs.cmdline not cached on second build: $out2"
+    exit 1
+}
+
+echo "OK"