feat: extend wasm backend entrypoints

scripts/build_linux.sh

@@ -12,29 +12,70 @@ mkdir bin/assets > /dev/null 2>&1
 mkdir work > /dev/null 2>&1
 
 COMPILER="clang++"
-FLAGS="-g -rdynamic -w -Wall -$OPT_FLAG -std=c++20 -fpermissive -ffast-math"
+# -rdynamic is a link-time flag (exports the binary's symbols so dlopen'd .uce
+# units resolve the runtime against it); the -c compiles below do not need it.
+FLAGS="-g -w -Wall -$OPT_FLAG -std=c++20 -fpermissive -ffast-math"
 
-# Wasmtime C API for the W4 wasm backend (src/wasm/backend.cpp).
+# Wasmtime C++ API — needed only by the wasm backend object (src/wasm).
 WASMTIME_HOME=${WASMTIME_HOME:-/opt/wasmtime}
 WASM_FLAGS="-I$WASMTIME_HOME/include"
 WASM_LIBS="-L$WASMTIME_HOME/lib -Wl,-rpath,$WASMTIME_HOME/lib -lwasmtime"
 
 LIBS="-ldl -lm -lpthread -lpcre2-8 `mysql_config --cflags --libs` $WASM_LIBS"
-SRCFLAGS="-D EXEC_NAME=\"$GF\" -D PLATFORM_NAME=\"linux\" $WASM_FLAGS"
+SRCFLAGS="-D EXEC_NAME=\"$GF\" -D PLATFORM_NAME=\"linux\""
 
-echo "Compiling SQLite..."
-clang -g -O2 -fPIC \
-	-DSQLITE_THREADSAFE=1 \
-	-DSQLITE_OMIT_LOAD_EXTENSION=1 \
-	-DSQLITE_DQS=0 \
-	-DSQLITE_DEFAULT_FOREIGN_KEYS=1 \
-	-DSQLITE_DEFAULT_WAL_SYNCHRONOUS=1 \
-	-c src/3rdparty/sqlite/sqlite3.c -o bin/sqlite3.o 2>&1
-if [ $? -ne 0 ]; then exit 1; fi
+# The runtime is split into separately-compiled objects so an edit to one
+# module no longer recompiles the others (notably: editing the wasm backend
+# does not recompile the rest, and vendored SQLite is built once):
+#   bin/sqlite3.o  vendored SQLite amalgamation (depends only on its own source)
+#   bin/wasm.o     wasm backend + worker + wasmtime.hh (src/wasm)
+#   bin/main.o     linux_fastcgi.cpp + the uce_lib core amalgamation
+# All link into the single -rdynamic binary, so the dlopen unit model is
+# unchanged. Delete bin/*.o to force a clean rebuild.
 
+# Rebuild $1 if it is missing or anything under the remaining find-args is newer.
+needs_rebuild() {
+	local obj="$1"; shift
+	[ ! -f "$obj" ] && return 0
+	[ -n "$(find "$@" -newer "$obj" -print -quit 2>/dev/null)" ] && return 0
+	return 1
+}
 
-echo "Compiling executable..."
-time -p $COMPILER src/linux_fastcgi.cpp bin/sqlite3.o $SRCFLAGS $FLAGS $LIBS -o bin/$GF.linux.bin 2>&1
+# SQLite: vendored C, depends only on its own source (not our headers).
+if needs_rebuild bin/sqlite3.o src/3rdparty/sqlite/sqlite3.c src/3rdparty/sqlite/sqlite3.h; then
+	echo "Compiling SQLite..."
+	clang -g -O2 -fPIC \
+		-DSQLITE_THREADSAFE=1 \
+		-DSQLITE_OMIT_LOAD_EXTENSION=1 \
+		-DSQLITE_DQS=0 \
+		-DSQLITE_DEFAULT_FOREIGN_KEYS=1 \
+		-DSQLITE_DEFAULT_WAL_SYNCHRONOUS=1 \
+		-c src/3rdparty/sqlite/sqlite3.c -o bin/sqlite3.o 2>&1 || exit 1
+else
+	echo "Reusing bin/sqlite3.o"
+fi
+
+# wasm backend object: the wasm sources plus the lib headers it includes for
+# declarations (not the lib .cpp — those are compiled into main.o).
+if needs_rebuild bin/wasm.o src/wasm src/lib/*.h; then
+	echo "Compiling wasm backend..."
+	time -p $COMPILER -c src/wasm/wasm_module.cpp $SRCFLAGS $FLAGS $WASM_FLAGS -o bin/wasm.o 2>&1 || exit 1
+else
+	echo "Reusing bin/wasm.o"
+fi
+
+# main object: the FastCGI entrypoint + the uce_lib core amalgamation. Depends
+# on linux_fastcgi.cpp, the whole lib tree, fcgicc, and the wasm backend header
+# (its only view of the wasm object) — but not the wasm .cpp sources.
+if needs_rebuild bin/main.o src/linux_fastcgi.cpp src/lib src/fastcgi src/wasm/backend.h; then
+	echo "Compiling main..."
+	time -p $COMPILER -c src/linux_fastcgi.cpp $SRCFLAGS $FLAGS -o bin/main.o 2>&1 || exit 1
+else
+	echo "Reusing bin/main.o"
+fi
+
+echo "Linking..."
+$COMPILER -rdynamic bin/main.o bin/wasm.o bin/sqlite3.o $FLAGS $LIBS -o bin/$GF.linux.bin 2>&1
 
 if [ $? -eq 0 ]
 then