wasm: add cmake build support

A few configure defines get changed:
QMAKE_WASM_PTHREAD_POOL_SIZE is now QT_WASM_PTHREAD_POOL_SIZE
QMAKE_WASM_TOTAL_MEMORY is now QT_WASM_INITIAL_MEMORY
QMAKE_WASM_SOURCE_MAP_BASE is now QT_WASM_SOURCE_MAP_BASE

device-option EMSCRIPTEN_ASYNCIFY=1 is QT_EMSCRIPTEN_ASYNCIFY=1

To create source maps for debugging. use
device-option QT_WASM_SOURCE_MAP=1

Task-number: QTBUG-78647
Change-Id: If9f30cd7fb408c386d6d69b5f7b1beecf1ab44b5
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

1 files changed, 92 insertions, 0 deletions

diff --git a/cmake/QtWasmHelpers.cmake b/cmake/QtWasmHelpers.cmake
new file mode 100644
index 0000000000..1bbe5c928f
--- /dev/null
+++ b/cmake/QtWasmHelpers.cmake
@@ -0,0 +1,92 @@
+
+function (qt_internal_setup_wasm_target_properties wasmTarget)
+
+    target_link_options("${wasmTarget}" INTERFACE "SHELL:-s EXIT_RUNTIME=1"
+    "SHELL:-s ERROR_ON_UNDEFINED_SYMBOLS=1"
+    "SHELL:-s EXTRA_EXPORTED_RUNTIME_METHODS=[UTF16ToString,stringToUTF16]"
+    "SHELL:-s USE_WEBGL2=1"
+    "--bind"
+    "SHELL:-s FETCH=1")
+
+    # Hardcode wasm memory size. Emscripten does not currently support memory growth
+    # (ALLOW_MEMORY_GROWTH) in pthreads mode, and requires specifying the memory size
+    # at build time. Further, browsers limit the maximum initial memory size to 1GB.
+    # QT_WASM_INITIAL_MEMORY must be a multiple of 64KB (i.e. 65536)
+    if(NOT DEFINED QT_WASM_INITIAL_MEMORY AND QT_FEATURE_thread)
+        set(QT_WASM_INITIAL_MEMORY "1GB")
+    endif()
+
+    if(DEFINED QT_WASM_INITIAL_MEMORY)
+        target_link_options("${wasmTarget}" INTERFACE "SHELL:-s INITIAL_MEMORY=${QT_WASM_INITIAL_MEMORY}")
+        message("Setting INITIAL_MEMORY to ${QT_WASM_INITIAL_MEMORY}")
+    endif()
+
+    if (QT_FEATURE_opengles3)
+        target_link_options("${wasmTarget}" INTERFACE "SHELL:-s FULL_ES3=1")
+
+        target_link_options("${wasmTarget}" INTERFACE "SHELL:-s FULL_ES3=1"
+            "SHELL:-s MAX_WEBGL_VERSION=2"
+            "SHELL:-s WEBGL2_BACKWARDS_COMPATIBILITY_EMULATION=1")
+    else()
+        target_link_options("${wasmTarget}" INTERFACE "SHELL:-s FULL_ES2=1")
+    endif()
+
+    set(disable_exceptions_catching 1)
+    if (QT_FEATURE_exceptions)
+        set(disable_exceptions_catching 0)
+    endif()
+    target_link_options("${wasmTarget}" INTERFACE "SHELL:-s DISABLE_EXCEPTION_CATCHING=${disable_exceptions_catching}")
+
+    if (QT_FEATURE_thread)
+        target_compile_options("${wasmTarget}" INTERFACE "SHELL:-s USE_PTHREADS=1")
+        target_link_options("${wasmTarget}" INTERFACE "SHELL:-s USE_PTHREADS=1")
+
+        if(DEFINED QT_WASM_PTHREAD_POOL_SIZE)
+            target_link_options("${wasmTarget}" INTERFACE "SHELL:-s PTHREAD_POOL_SIZE=${QT_WASM_PTHREAD_POOL_SIZE}")
+            message("Setting PTHREAD_POOL_SIZE to ${QT_WASM_PTHREAD_POOL_SIZE}")
+        endif()
+
+    else()
+        target_link_options("${wasmTarget}" INTERFACE "SHELL:-s ALLOW_MEMORY_GROWTH=1")
+    endif()
+
+    # debug add_compile_options
+    if ("QT_WASM_SOURCE_MAP=1" IN_LIST QT_QMAKE_DEVICE_OPTIONS)
+        set(WASM_SOURCE_MAP_BASE "http://localhost:8000/")
+
+        if(DEFINED QT_WASM_SOURCE_MAP_BASE)
+            set(WASM_SOURCE_MAP_BASE "${QT_WASM_SOURCE_MAP_BASE}")
+        endif()
+
+        # Pass --source-map-base on the linker line. This informs the
+        # browser where to find the source files when debugging.
+        # -g4 to make source maps for debugging
+        target_link_options("${wasmTarget}" INTERFACE  "-g4" "--source-map-base" "${WASM_SOURCE_MAP_BASE}")
+
+    endif()
+
+    # a few good defaults to make console more verbose while debugging
+    target_link_options("${wasmTarget}" INTERFACE $<$<CONFIG:Debug>:
+        SHELL:"-s DEMANGLE_SUPPORT=1"
+        SHELL:"-s GL_DEBUG=1"
+        SHELL:"-s ASSERTIONS=2"
+        --profiling-funcs>)
+
+    # target_link_options("${wasmTarget}" INTERFACE "SHELL:-s LIBRARY_DEBUG=1") # print out library calls, verbose
+    # target_link_options("${wasmTarget}" INTERFACE "SHELL:-s SYSCALL_DEBUG=1") # print out sys calls, verbose
+    # target_link_options("${wasmTarget}" INTERFACE "SHELL:-s FS_LOG=1") # print out filesystem ops, verbose
+    # target_link_options("${wasmTarget}" INTERFACE "SHELL:-s SOCKET_DEBUG") # print out socket,network data transfer
+
+    if ("QT_EMSCRIPTEN_ASYNCIFY=1" IN_LIST QT_QMAKE_DEVICE_OPTIONS)
+
+        # Emscripten recommends building with optimizations when using asyncify
+        # in order to reduce wasm file size, and may also generate broken wasm
+        # (with "wasm validation error: too many locals" type errors) if optimizations
+        # are omitted. Enable optimizations also for debug builds.
+        set(QT_CFLAGS_OPTIMIZE_DEBUG "-Os" CACHE STRING INTERNAL FORCE)
+        set(QT_FEATURE_optimize_debug ON CACHE BOOL INTERNAL FORCE)
+
+        target_link_options("${wasmTarget}" INTERFACE "SHELL:-s ASYNCIFY" "-Os")
+        target_compile_definitions("${wasmTarget}" INTERFACE QT_HAVE_EMSCRIPTEN_ASYNCIFY)
+    endif()
+endfunction()