Add wasm-bindgen support

.circleci/config.yml

@@ -77,6 +77,7 @@ commands:
             curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
             export PATH=${HOME}/.cargo/bin:${PATH}
             rustup target add wasm32-unknown-emscripten
+            cargo install wasm-bindgen-cli
             echo "export PATH=\"\$HOME/.cargo/bin:\$PATH\"" >> $BASH_ENV
   install-node-version:
     description: "install a specific version of node"
@@ -159,6 +160,7 @@ commands:
             # We use an out-of-tree cache directory so it can be part of the
             # persisted workspace (see below).
             echo "CACHE = os.path.expanduser('~/cache')" >> .emscripten
+            echo "WASM_BINDGEN = os.path.expanduser('~/.cargo/bin/wasm-bindgen')" >> .emscripten
             # Refer to commit 0bc3640 if we need to pin V8 version.
             echo "V8_ENGINE = [os.path.expanduser('~/.jsvu/bin/v8')]" >> .emscripten
             echo "JS_ENGINES = [NODE_JS]" >> .emscripten

emcc.py

@@ -27,7 +27,6 @@
 import shutil
 import sys
 import tarfile
-from dataclasses import dataclass
 from enum import Enum, auto, unique
 
 # This assert needs to happen early, before any too-recent python syntax is used.
@@ -51,7 +50,7 @@
 from tools.settings import COMPILE_TIME_SETTINGS, default_setting, settings, user_settings
 from tools.shared import DEBUG, DYLIB_EXTENSIONS, in_temp
 from tools.toolchain_profiler import ToolchainProfiler
-from tools.utils import exit_with_error, get_file_suffix, read_file, unsuffixed_basename
+from tools.utils import LinkFlag, exit_with_error, get_file_suffix, read_file, unsuffixed_basename
 
 logger = logging.getLogger('emcc')
 
@@ -96,20 +95,6 @@ class Mode(Enum):
   COMPILE_AND_LINK = auto()
 
 
-@dataclass
-class LinkFlag:
-  """Used to represent a linker flag.
-
-  The flag value is stored along with a bool that distinguishes input
-  files from non-files.
-
-  A list of these is returned by separate_linker_flags.
-  """
-
-  value: str
-  is_file: int
-
-
 class EmccState:
   def __init__(self, args):
     self.mode = Mode.COMPILE_AND_LINK
@@ -578,7 +563,7 @@ def compile_source_file(input_file):
       # Default to assuming the inputs are object files and pass them to the linker
       pass
 
-  return [f.value for f in linker_args]
+  return linker_args
 
 
 if __name__ == '__main__':

site/source/docs/tools_reference/settings_reference.rst

@@ -3284,6 +3284,15 @@ Example use ``-sSIGNATURE_CONVERSIONS=someFunction:_p,anotherFunction:p``
 
 Default value: []
 
+.. _wasm_bindgen:
+
+WASM_BINDGEN
+============
+
+Run wasm-bindgen and integrate the rust-exported symbols into the rest of Emscripten's JS output.
+
+Default value: 0
+
 .. _source_phase_imports:
 
 SOURCE_PHASE_IMPORTS

src/runtime_common.js

@@ -79,7 +79,7 @@ if (ENVIRONMENT_IS_NODE && {{{ ENVIRONMENT_IS_WORKER_THREAD() }}}) {
 
 // Memory management
 
-#if SUPPORT_BIG_ENDIAN
+#if SUPPORT_BIG_ENDIAN || WASM_BINDGEN
 /** @type {!DataView} */
 var HEAP_DATA_VIEW;
 #endif
@@ -130,8 +130,10 @@ function updateMemoryViews() {
   {{{ maybeExportHeap('HEAP64')  }}}HEAP64 = new BigInt64Array(b);
   {{{ maybeExportHeap('HEAPU64') }}}HEAPU64 = new BigUint64Array(b);
 #endif
+#if SUPPORT_BIG_ENDIAN || WASM_BINDGEN
+  {{{ maybeExportHeap('HEAP_DATA_VIEW') }}}HEAP_DATA_VIEW = new DataView(b);
+#endif
 #if SUPPORT_BIG_ENDIAN
-  {{{ maybeExportHeap('HEAP_DATA_VIEW') }}} HEAP_DATA_VIEW = new DataView(b);
   LE_HEAP_UPDATE();
 #endif
 }

src/settings.js

@@ -2164,6 +2164,10 @@ var LEGACY_RUNTIME = false;
 // [link]
 var SIGNATURE_CONVERSIONS = [];
 
+// Run wasm-bindgen and integrate the rust-exported symbols into the rest of Emscripten's JS output.
+// [link]
+var WASM_BINDGEN = 0;
+
 // Experimental support for wasm source phase imports.
 // This is only currently implemented in the pre-release/nightly version of
 // node, and not yet supported by browsers.

test/common.py

@@ -1374,8 +1374,7 @@ def ccshared(src, linkto=None):
         cfunc_ptr();
         return 0;
       }
-    ''' % locals(),
-           'a: loaded\na: b (prev: (null))\na: c (prev: b)\n', cflags=extra_args)
+    ''', 'a: loaded\na: b (prev: (null))\na: c (prev: b)\n', cflags=extra_args)
 
   def do_run(self, src, expected_output=None, force_c=False, **kwargs):
     if 'no_build' in kwargs:

test/rust/basics/.cargo/config.toml

@@ -0,0 +1,2 @@
+[build]
+target = "wasm32-unknown-emscripten"

test/rust/bindgen_integration/.cargo/config.toml

@@ -0,0 +1,7 @@
+[build]
+target = "wasm32-unknown-emscripten"
+rustflags = [
+    "-Cllvm-args=-enable-emscripten-cxx-exceptions=0",
+    "-Cpanic=abort",
+    "-Crelocation-model=static",
+]

test/rust/bindgen_integration/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "bindgen_integration"
+edition = "2021"
+
+[lib]
+crate-type = ["staticlib"]
+
+[dependencies]

test/rust/bindgen_integration/src/lib.rs

@@ -0,0 +1,6 @@
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+pub fn rs_add(a: i32, b: i32) -> i32 {
+    return a + b;
+}

test/test_other.py

@@ -14845,7 +14845,7 @@ def test_embool(self):
   @requires_rust
   def test_rust_integration_basics(self):
     copytree(test_file('rust/basics'), '.')
-    self.run_process(['cargo', 'build', '--target=wasm32-unknown-emscripten'])
+    self.run_process(['cargo', 'build'])
     lib = 'target/wasm32-unknown-emscripten/debug/libbasics.a'
     self.assertExists(lib)
 
@@ -14857,6 +14857,31 @@ def test_rust_integration_basics(self):
     }''')
     self.do_runf('main.cpp', 'Hello from rust!', cflags=[lib])
 
+  @requires_rust
+  def test_wasm_bindgen_integration(self):
+    copytree(test_file('rust/bindgen_integration'), '.')
+    self.run_process(['cargo', 'add', 'wasm-bindgen'])
+    self.run_process(['cargo', 'build'])
+    lib = 'target/wasm32-unknown-emscripten/debug/libbindgen_integration.a'
+    self.assertExists(lib)
+    self.assertExists(os.path.abspath(config.WASM_BINDGEN[0]))
+
+    create_file('main.cpp', '')
+    create_file('post.js', '''
+      Module.onRuntimeInitialized = () => {
+        out(Module.rs_add(17, 25));
+      };
+    ''')
+    emcc_args = [
+        lib,
+        '-sWASM_BINDGEN',
+        '--post-js',
+        'post.js',
+        '-lexports.js',
+    ]
+
+    self.do_runf('main.cpp', '42', cflags=emcc_args)
+
   def test_relative_em_cache(self):
     with env_modify({'EM_CACHE': 'foo'}):
       self.assert_fail([EMCC, '-c', test_file('hello_world.c')], 'emcc: error: environment variable EM_CACHE must be an absolute path: foo')

tools/building.py

@@ -273,12 +273,43 @@ def lld_flags_for_executable(external_symbols):
   return cmd
 
 
-def lld_flags(args):
+def get_wasm_bindgen_exported_symbols(input_files):
+  if not os.path.exists(LLVM_NM):
+    exit_with_error('llvm-nm not found in LLVM directory: %s', LLVM_NM)
+
+  nm_args = [
+      LLVM_NM,
+      '--defined-only',
+      '--extern-only',
+      '--format=just-symbols',
+      '--print-file-name',
+      '--quiet',
+  ]
+  if input_files is not None:
+    nm_args += input_files
+
+  result = run_process(nm_args, stdout=subprocess.PIPE)
+  symbols = []
+  for line in result.stdout.splitlines():
+    (path, symbol) = line.split()
+    # Skip mangled (non-C) symbols
+    if symbol.startswith(('_Z', '_R', 'anon.')):
+      continue
+    symbols.append(symbol)
+
+  return symbols
+
+
+def lld_flags(args, linker_inputs=None):
   # lld doesn't currently support --start-group/--end-group since the
   # semantics are more like the windows linker where there is no need for
   # grouping.
   args = [a for a in args if a not in {'--start-group', '--end-group'}]
 
+  if settings.WASM_BINDGEN:
+    exported_symbols = get_wasm_bindgen_exported_symbols(linker_inputs)
+    args.extend(f'--export-if-defined={e}' for e in exported_symbols)
+
   # Emscripten currently expects linkable output (SIDE_MODULE/MAIN_MODULE) to
   # include all archive contents.
   if settings.LINKABLE:
@@ -312,7 +343,7 @@ def lld_flags(args):
   return args
 
 
-def link_lld(args, target, external_symbols=None):
+def link_lld(args, target, external_symbols=None, linker_inputs=None):
   # runs lld to link things.
   if not os.path.exists(WASM_LD):
     exit_with_error('linker binary not found in LLVM directory: %s', WASM_LD)
@@ -321,7 +352,7 @@ def link_lld(args, target, external_symbols=None):
   # normal linker flags that are used when building and executable
   if '--relocatable' not in args and '-r' not in args:
     cmd += lld_flags_for_executable(external_symbols)
-  cmd += lld_flags(args)
+  cmd += lld_flags(args, linker_inputs)
   cmd = get_command_with_possible_response_file(cmd)
   check_call(cmd)
 
@@ -1254,6 +1285,28 @@ def run_wasm_opt(infile, outfile=None, args=[], **kwargs):  # noqa
   return run_binaryen_command('wasm-opt', infile, outfile, args=args, **kwargs)
 
 
+def run_wasm_bindgen(infile, outfile=None, args=[], **kwargs):  # noqa
+  bindgen_out_dir = get_emscripten_temp_dir() + '/bindgen_out/'
+
+  cmd = config.WASM_BINDGEN + [
+    infile,
+    '--keep-lld-exports',
+    '--keep-debug',
+    '--out-dir',
+    bindgen_out_dir,
+  ]
+  check_call(cmd)
+
+  # Don't try to predict the .wasm filename that wasm-bindgen outputs. Instead
+  # just grab the .wasm file itself.
+  all_output_files = os.listdir(bindgen_out_dir)
+  new_wasm_file = list(filter(lambda x: x.endswith('.wasm'), all_output_files))[0]
+  if outfile is None:
+    outfile = infile
+
+  shutil.copyfile(bindgen_out_dir + new_wasm_file, outfile)
+
+
 intermediate_counter = 0
 
 

tools/config.py

@@ -27,6 +27,7 @@
 CACHE = None
 PORTS = None
 COMPILER_WRAPPER = None
+WASM_BINDGEN = None
 
 # Set by init()
 EM_CONFIG = None
@@ -60,6 +61,7 @@ def fix_js_engine(old, new):
 def normalize_config_settings():
   global CACHE, PORTS, LLVM_ADD_VERSION, CLANG_ADD_VERSION, CLOSURE_COMPILER
   global NODE_JS, NODE_JS_TEST, V8_ENGINE, JS_ENGINES, SPIDERMONKEY_ENGINE, WASM_ENGINES
+  global WASM_BINDGEN
 
   SPIDERMONKEY_ENGINE = fix_js_engine(SPIDERMONKEY_ENGINE, listify(SPIDERMONKEY_ENGINE))
   NODE_JS = fix_js_engine(NODE_JS, listify(NODE_JS))
@@ -68,6 +70,7 @@ def normalize_config_settings():
   JS_ENGINES = [listify(engine) for engine in JS_ENGINES]
   WASM_ENGINES = [listify(engine) for engine in WASM_ENGINES]
   CLOSURE_COMPILER = listify(CLOSURE_COMPILER)
+  WASM_BINDGEN = listify(WASM_BINDGEN)
   if not CACHE:
     CACHE = path_from_root('cache')
   if not PORTS:
@@ -131,6 +134,7 @@ def parse_config_file():
     'CACHE',
     'PORTS',
     'COMPILER_WRAPPER',
+    'WASM_BINDGEN',
   )
 
   # Only propagate certain settings from the config file.

tools/emscripten.py

@@ -680,7 +680,7 @@ def create_tsd_exported_runtime_methods(metadata):
   return utils.read_file(in_temp(f'{file}.d.ts'))
 
 
-def create_tsd(metadata, embind_tsd):
+def create_tsd(metadata, embind_tsd, bindgen_tsd=None):
   out = '// TypeScript bindings for emscripten-generated code.  Automatically generated at compile time.\n'
   if settings.EXPORTED_RUNTIME_METHODS:
     out += create_tsd_exported_runtime_methods(metadata)
@@ -712,6 +712,12 @@ def create_tsd(metadata, embind_tsd):
   # Add in embind definitions.
   if embind_tsd:
     export_interfaces += ' & EmbindModule'
+  if settings.WASM_BINDGEN and bindgen_tsd:
+    for file_path in bindgen_tsd:
+      with open(file_path, encoding='utf-8') as file:
+          for line in file:
+              out += f'{line}'
+    export_interfaces += ' & BindgenModule'
   out += f'export type MainModule = {export_interfaces};\n'
   if settings.MODULARIZE:
     return_type = 'MainModule'