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# Copyright 2011 The Emscripten Authors. All rights reserved.
# Emscripten is available under two separate licenses, the MIT license and the
# University of Illinois/NCSA Open Source License. Both these licenses can be
# found in the LICENSE file.
from .toolchain_profiler import ToolchainProfiler
import base64
import glob
import hashlib
import json
import logging
import os
import re
import shlex
import stat
import shutil
import sys
import time
from subprocess import PIPE
from urllib.parse import quote
from . import building
from . import cache
from . import config
from . import diagnostics
from . import emscripten
from . import feature_matrix
from . import filelock
from . import js_manipulation
from . import ports
from . import shared
from . import system_libs
from . import utils
from . import webassembly
from .utils import read_file, read_binary, write_file, delete_file
from .utils import removeprefix, exit_with_error
from .shared import in_temp, safe_copy, do_replace, run_process, OFormat
from .shared import DEBUG, WINDOWS, DYNAMICLIB_ENDINGS, STATICLIB_ENDINGS
from .shared import unsuffixed, unsuffixed_basename, get_file_suffix
from .settings import settings, default_setting, user_settings
from .minimal_runtime_shell import generate_minimal_runtime_html
import tools.line_endings
logger = logging.getLogger('link')
DEFAULT_SHELL_HTML = utils.path_from_root('src/shell.html')
DEFAULT_ASYNCIFY_IMPORTS = ['__asyncjs__*']
DEFAULT_ASYNCIFY_EXPORTS = [
'main',
'__main_argc_argv',
# Embind's async template wrapper functions. These functions are usually in
# the function pointer table and not called from exports, but we need to name
# them so the JSPI pass can find and convert them.
'_ZN10emscripten8internal5async*'
]
VALID_ENVIRONMENTS = ('web', 'webview', 'worker', 'node', 'shell')
EXECUTABLE_ENDINGS = ['.wasm', '.html', '.js', '.mjs', '.out', '']
# Supported LLD flags which we will pass through to the linker.
SUPPORTED_LINKER_FLAGS = (
'--start-group', '--end-group',
'-(', '-)',
'--whole-archive', '--no-whole-archive',
'-whole-archive', '-no-whole-archive'
)
# Unsupported LLD flags which we will ignore.
# Maps to true if the flag takes an argument.
UNSUPPORTED_LLD_FLAGS = {
# macOS-specific linker flag that libtool (ltmain.sh) will if macOS is detected.
'-bind_at_load': False,
# wasm-ld doesn't support soname or other dynamic linking flags (yet). Ignore them
# in order to aid build systems that want to pass these flags.
'-soname': True,
'-allow-shlib-undefined': False,
'-rpath': True,
'-rpath-link': True,
'-version-script': True,
'-install_name': True,
}
UBSAN_SANITIZERS = {
'alignment',
'bool',
'builtin',
'bounds',
'enum',
'float-cast-overflow',
'float-divide-by-zero',
'function',
'implicit-unsigned-integer-truncation',
'implicit-signed-integer-truncation',
'implicit-integer-sign-change',
'integer-divide-by-zero',
'nonnull-attribute',
'null',
'nullability-arg',
'nullability-assign',
'nullability-return',
'object-size',
'pointer-overflow',
'return',
'returns-nonnull-attribute',
'shift',
'signed-integer-overflow',
'unreachable',
'unsigned-integer-overflow',
'vla-bound',
'vptr',
'undefined',
'undefined-trap',
'implicit-integer-truncation',
'implicit-integer-arithmetic-value-change',
'implicit-conversion',
'integer',
'nullability',
}
final_js = None
# this function uses the global 'final' variable, which contains the current
# final output file. if a method alters final, and calls this method, then it
# must modify final globally (i.e. it can't receive final as a param and
# return it)
# TODO: refactor all this, a singleton that abstracts over the final output
# and saving of intermediates
def save_intermediate(name, suffix='js'):
if not DEBUG:
return
if not final_js:
logger.debug(f'(not saving intermediate {name} because not generating JS)')
return
building.save_intermediate(final_js, f'{name}.{suffix}')
def save_intermediate_with_wasm(name, wasm_binary):
if not DEBUG:
return
save_intermediate(name) # save the js
building.save_intermediate(wasm_binary, name + '.wasm')
def base64_encode(b):
b64 = base64.b64encode(b)
return b64.decode('ascii')
def align_to_wasm_page_boundary(address):
page_size = webassembly.WASM_PAGE_SIZE
return ((address + (page_size - 1)) // page_size) * page_size
def will_metadce():
# The metadce JS parsing code does not currently support the JS that gets generated
# when assertions are enabled.
if settings.ASSERTIONS:
return False
return settings.OPT_LEVEL >= 3 or settings.SHRINK_LEVEL >= 1
def setup_environment_settings():
# Environment setting based on user input
environments = settings.ENVIRONMENT.split(',')
if any([x for x in environments if x not in VALID_ENVIRONMENTS]):
exit_with_error(f'Invalid environment specified in "ENVIRONMENT": {settings.ENVIRONMENT}. Should be one of: {",".join(VALID_ENVIRONMENTS)}')
settings.ENVIRONMENT_MAY_BE_WEB = not settings.ENVIRONMENT or 'web' in environments
settings.ENVIRONMENT_MAY_BE_WEBVIEW = not settings.ENVIRONMENT or 'webview' in environments
settings.ENVIRONMENT_MAY_BE_NODE = not settings.ENVIRONMENT or 'node' in environments
settings.ENVIRONMENT_MAY_BE_SHELL = not settings.ENVIRONMENT or 'shell' in environments
# The worker case also includes Node.js workers when pthreads are
# enabled and Node.js is one of the supported environments for the build to
# run on. Node.js workers are detected as a combination of
# ENVIRONMENT_IS_WORKER and ENVIRONMENT_IS_NODE.
settings.ENVIRONMENT_MAY_BE_WORKER = \
not settings.ENVIRONMENT or \
'worker' in environments or \
(settings.ENVIRONMENT_MAY_BE_NODE and settings.PTHREADS)
if not settings.ENVIRONMENT_MAY_BE_WORKER and settings.PROXY_TO_WORKER:
exit_with_error('If you specify --proxy-to-worker and specify a "-sENVIRONMENT=" directive, it must include "worker" as a target! (Try e.g. -sENVIRONMENT=web,worker)')
if not settings.ENVIRONMENT_MAY_BE_WORKER and settings.SHARED_MEMORY:
exit_with_error('When building with multithreading enabled and a "-sENVIRONMENT=" directive is specified, it must include "worker" as a target! (Try e.g. -sENVIRONMENT=web,worker)')
def embed_memfile(options):
return (settings.SINGLE_FILE or
(settings.WASM2JS and not options.memory_init_file and
(not settings.MAIN_MODULE and
not settings.SIDE_MODULE and
not settings.GENERATE_SOURCE_MAP)))
def is_ar_file_with_missing_index(archive_file):
# We parse the archive header outselves because llvm-nm --print-armap is slower and less
# reliable.
# See: https://github.com/emscripten-core/emscripten/issues/10195
archive_header = b'!<arch>\n'
file_header_size = 60
with open(archive_file, 'rb') as f:
header = f.read(len(archive_header))
if header != archive_header:
# This is not even an ar file
return False
file_header = f.read(file_header_size)
if len(file_header) != file_header_size:
# We don't have any file entires at all so we don't consider the index missing
return False
name = file_header[:16].strip()
# If '/' is the name of the first file we have an index
return name != b'/'
def ensure_archive_index(archive_file):
# Fastcomp linking works without archive indexes.
if not settings.AUTO_ARCHIVE_INDEXES:
return
if is_ar_file_with_missing_index(archive_file):
diagnostics.warning('emcc', '%s: archive is missing an index; Use emar when creating libraries to ensure an index is created', archive_file)
diagnostics.warning('emcc', '%s: adding index', archive_file)
run_process([shared.LLVM_RANLIB, archive_file])
def generate_js_sym_info():
# Runs the js compiler to generate a list of all symbols available in the JS
# libraries. This must be done separately for each linker invokation since the
# list of symbols depends on what settings are used.
# TODO(sbc): Find a way to optimize this. Potentially we could add a super-set
# mode of the js compiler that would generate a list of all possible symbols
# that could be checked in.
_, forwarded_data = emscripten.compile_javascript(symbols_only=True)
# When running in symbols_only mode compiler.mjs outputs a flat list of C symbols.
return json.loads(forwarded_data)
@ToolchainProfiler.profile_block('JS symbol generation')
def get_js_sym_info():
# Avoiding using the cache when generating struct info since
# this step is performed while the cache is locked.
if DEBUG or settings.BOOTSTRAPPING_STRUCT_INFO or config.FROZEN_CACHE:
return generate_js_sym_info()
# We define a cache hit as when the settings and `--js-library` contents are
# identical.
# Ignore certain settings that can are no relevant to library deps. Here we
# skip PRE_JS_FILES/POST_JS_FILES which don't effect the library symbol list
# and can contain full paths to temporary files.
skip_settings = {'PRE_JS_FILES', 'POST_JS_FILES'}
input_files = [json.dumps(settings.external_dict(skip_keys=skip_settings), sort_keys=True, indent=2)]
for jslib in sorted(glob.glob(utils.path_from_root('src') + '/library*.js')):
input_files.append(read_file(jslib))
for jslib in settings.JS_LIBRARIES:
if not os.path.isabs(jslib):
jslib = utils.path_from_root('src', jslib)
input_files.append(read_file(jslib))
content = '\n'.join(input_files)
content_hash = hashlib.sha1(content.encode('utf-8')).hexdigest()
def build_symbol_list(filename):
"""Only called when there is no existing symbol list for a given content hash.
"""
library_syms = generate_js_sym_info()
write_file(filename, json.dumps(library_syms, separators=(',', ':'), indent=2))
# We need to use a separate lock here for symbol lists because, unlike with system libraries,
# it's normally for these file to get pruned as part of normal operation. This means that it
# can be deleted between the `cache.get()` then the `read_file`.
with filelock.FileLock(cache.get_path(cache.get_path('symbol_lists.lock'))):
filename = cache.get(f'symbol_lists/{content_hash}.json', build_symbol_list)
library_syms = json.loads(read_file(filename))
# Limit of the overall size of the cache to 100 files.
# This code will get test coverage since a full test run of `other` or `core`
# generates ~1000 unique symbol lists.
cache_limit = 500
root = cache.get_path('symbol_lists')
if len(os.listdir(root)) > cache_limit:
files = []
for f in os.listdir(root):
f = os.path.join(root, f)
files.append((f, os.path.getmtime(f)))
files.sort(key=lambda x: x[1])
# Delete all but the newest N files
for f, _ in files[:-cache_limit]:
delete_file(f)
return library_syms
def filter_link_flags(flags, using_lld):
def is_supported(f):
if using_lld:
for flag, takes_arg in UNSUPPORTED_LLD_FLAGS.items():
# lld allows various flags to have either a single -foo or double --foo
if f.startswith(flag) or f.startswith('-' + flag):
diagnostics.warning('linkflags', 'ignoring unsupported linker flag: `%s`', f)
# Skip the next argument if this linker flag takes and argument and that
# argument was not specified as a separately (i.e. it was specified as
# single arg containing an `=` char.)
skip_next = takes_arg and '=' not in f
return False, skip_next
return True, False
else:
if f in SUPPORTED_LINKER_FLAGS:
return True, False
# Silently ignore -l/-L flags when not using lld. If using lld allow
# them to pass through the linker
if f.startswith('-l') or f.startswith('-L'):
return False, False
diagnostics.warning('linkflags', 'ignoring unsupported linker flag: `%s`', f)
return False, False
results = []
skip_next = False
for f in flags:
if skip_next:
skip_next = False
continue
keep, skip_next = is_supported(f[1])
if keep:
results.append(f)
return results
def fix_windows_newlines(text):
# Avoid duplicating \r\n to \r\r\n when writing out text.
if WINDOWS:
text = text.replace('\r\n', '\n')
return text
def read_js_files(files):
contents = '\n'.join(read_file(f) for f in files)
return fix_windows_newlines(contents)
def should_run_binaryen_optimizer():
# run the binaryen optimizer in -O2+. in -O0 we don't need it obviously, while
# in -O1 we don't run it as the LLVM optimizer has been run, and it does the
# great majority of the work; not running the binaryen optimizer in that case
# keeps -O1 mostly-optimized while compiling quickly and without rewriting
# DWARF etc.
return settings.OPT_LEVEL >= 2
def remove_trailing_zeros(memfile):
mem_data = utils.read_binary(memfile)
mem_data = mem_data.rstrip(b'\0')
utils.write_binary(memfile, mem_data)
def get_binaryen_passes(memfile):
passes = []
optimizing = should_run_binaryen_optimizer()
# wasm-emscripten-finalize will strip the features section for us
# automatically, but if we did not modify the wasm then we didn't run it,
# and in an optimized build we strip it manually here. (note that in an
# unoptimized build we might end up with the features section, if we neither
# optimize nor run wasm-emscripten-finalize, but a few extra bytes in the
# binary don't matter in an unoptimized build)
if optimizing:
passes += ['--strip-target-features']
# safe heap must run before post-emscripten, so post-emscripten can apply the sbrk ptr
if settings.SAFE_HEAP:
passes += ['--safe-heap']
# sign-ext is enabled by default by llvm. If the target browser settings don't support
# this we lower it away here using a binaryen pass.
if not feature_matrix.caniuse(feature_matrix.Feature.SIGN_EXT):
logger.debug('lowering sign-ext feature due to incompatiable target browser engines')
passes += ['--signext-lowering']
if optimizing:
passes += ['--post-emscripten']
if settings.SIDE_MODULE:
passes += ['--pass-arg=post-emscripten-side-module']
if optimizing:
passes += [building.opt_level_to_str(settings.OPT_LEVEL, settings.SHRINK_LEVEL)]
# when optimizing, use the fact that low memory is never used (1024 is a
# hardcoded value in the binaryen pass)
if optimizing and settings.GLOBAL_BASE >= 1024:
passes += ['--low-memory-unused']
if settings.AUTODEBUG:
# adding '--flatten' here may make these even more effective
passes += ['--instrument-locals']
passes += ['--log-execution']
passes += ['--instrument-memory']
if settings.LEGALIZE_JS_FFI:
# legalize it again now, as the instrumentation may need it
passes += ['--legalize-js-interface']
passes += building.js_legalization_pass_flags()
if settings.EMULATE_FUNCTION_POINTER_CASTS:
# note that this pass must run before asyncify, as if it runs afterwards we only
# generate the byn$fpcast_emu functions after asyncify runs, and so we wouldn't
# be able to further process them.
passes += ['--fpcast-emu']
if settings.ASYNCIFY == 1:
passes += ['--asyncify']
if settings.MAIN_MODULE or settings.SIDE_MODULE:
passes += ['--pass-arg=asyncify-relocatable']
if settings.ASSERTIONS:
passes += ['--pass-arg=asyncify-asserts']
if settings.ASYNCIFY_ADVISE:
passes += ['--pass-arg=asyncify-verbose']
if settings.ASYNCIFY_IGNORE_INDIRECT:
passes += ['--pass-arg=asyncify-ignore-indirect']
passes += ['--pass-arg=asyncify-imports@%s' % ','.join(settings.ASYNCIFY_IMPORTS)]
# shell escaping can be confusing; try to emit useful warnings
def check_human_readable_list(items):
for item in items:
if item.count('(') != item.count(')'):
logger.warning('emcc: ASYNCIFY list contains an item without balanced parentheses ("(", ")"):')
logger.warning(' ' + item)
logger.warning('This may indicate improper escaping that led to splitting inside your names.')
logger.warning('text file, one line per function.')
break
if settings.ASYNCIFY_REMOVE:
check_human_readable_list(settings.ASYNCIFY_REMOVE)
passes += ['--pass-arg=asyncify-removelist@%s' % ','.join(settings.ASYNCIFY_REMOVE)]
if settings.ASYNCIFY_ADD:
check_human_readable_list(settings.ASYNCIFY_ADD)
passes += ['--pass-arg=asyncify-addlist@%s' % ','.join(settings.ASYNCIFY_ADD)]
if settings.ASYNCIFY_ONLY:
check_human_readable_list(settings.ASYNCIFY_ONLY)
passes += ['--pass-arg=asyncify-onlylist@%s' % ','.join(settings.ASYNCIFY_ONLY)]
elif settings.ASYNCIFY == 2:
passes += ['--jspi']
passes += ['--pass-arg=jspi-imports@%s' % ','.join(settings.ASYNCIFY_IMPORTS)]
passes += ['--pass-arg=jspi-exports@%s' % ','.join(settings.ASYNCIFY_EXPORTS)]
if settings.SPLIT_MODULE:
passes += ['--pass-arg=jspi-split-module']
if settings.MEMORY64 == 2:
passes += ['--memory64-lowering']
if memfile:
passes += [
f'--separate-data-segments={memfile}',
f'--pass-arg=separate-data-segments-global-base@{settings.GLOBAL_BASE}'
]
if settings.BINARYEN_IGNORE_IMPLICIT_TRAPS:
passes += ['--ignore-implicit-traps']
# normally we can assume the memory, if imported, has not been modified
# beforehand (in fact, in most cases the memory is not even imported anyhow,
# but it is still safe to pass the flag), and is therefore filled with zeros.
# the one exception is dynamic linking of a side module: the main module is ok
# as it is loaded first, but the side module may be assigned memory that was
# previously used.
if optimizing and not settings.SIDE_MODULE:
passes += ['--zero-filled-memory']
# LLVM output always has immutable initial table contents: the table is
# fixed and may only be appended to at runtime (that is true even in
# relocatable mode)
if optimizing:
passes += ['--pass-arg=directize-initial-contents-immutable']
if settings.BINARYEN_EXTRA_PASSES:
# BINARYEN_EXTRA_PASSES is comma-separated, and we support both '-'-prefixed and
# unprefixed pass names
extras = settings.BINARYEN_EXTRA_PASSES.split(',')
passes += [('--' + p) if p[0] != '-' else p for p in extras if p]
return passes
def make_js_executable(script):
src = read_file(script)
cmd = config.NODE_JS
if settings.MEMORY64 == 1:
cmd += shared.node_memory64_flags()
elif settings.WASM_BIGINT:
cmd += shared.node_bigint_flags(config.NODE_JS)
if len(cmd) > 1 or not os.path.isabs(cmd[0]):
# Using -S (--split-string) here means that arguments to the executable are
# correctly parsed. We don't do this by default because old versions of env
# don't support -S.
cmd = '/usr/bin/env -S ' + shared.shlex_join(cmd)
else:
cmd = shared.shlex_join(cmd)
logger.debug('adding `#!` to JavaScript file: %s' % cmd)
# add shebang
with open(script, 'w') as f:
f.write('#!%s\n' % cmd)
f.write(src)
try:
os.chmod(script, stat.S_IMODE(os.stat(script).st_mode) | stat.S_IXUSR) # make executable
except OSError:
pass # can fail if e.g. writing the executable to /dev/null
def do_split_module(wasm_file, options):
os.rename(wasm_file, wasm_file + '.orig')
args = ['--instrument']
if options.requested_debug:
# Tell wasm-split to preserve function names.
args += ['-g']
building.run_binaryen_command('wasm-split', wasm_file + '.orig', outfile=wasm_file, args=args)
def setup_pthreads(target):
if settings.RELOCATABLE:
# phtreads + dyanmic linking has certain limitations
if settings.SIDE_MODULE:
diagnostics.warning('experimental', '-sSIDE_MODULE + pthreads is experimental')
elif settings.MAIN_MODULE:
diagnostics.warning('experimental', '-sMAIN_MODULE + pthreads is experimental')
elif settings.LINKABLE:
diagnostics.warning('experimental', '-sLINKABLE + pthreads is experimental')
if settings.ALLOW_MEMORY_GROWTH:
diagnostics.warning('pthreads-mem-growth', '-pthread + ALLOW_MEMORY_GROWTH may run non-wasm code slowly, see https://github.com/WebAssembly/design/issues/1271')
default_setting('DEFAULT_PTHREAD_STACK_SIZE', settings.STACK_SIZE)
# Functions needs to be exported from the module since they are used in worker.js
settings.REQUIRED_EXPORTS += [
'_emscripten_thread_free_data',
'emscripten_main_runtime_thread_id',
'emscripten_main_thread_process_queued_calls',
'_emscripten_run_on_main_thread_js',
'emscripten_stack_set_limits',
]
if settings.MAIN_MODULE:
settings.REQUIRED_EXPORTS += [
'_emscripten_dlsync_self',
'_emscripten_dlsync_self_async',
'_emscripten_proxy_dlsync',
'_emscripten_proxy_dlsync_async',
'__dl_seterr',
]
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += [
'$exitOnMainThread',
]
# Some symbols are required by worker.js.
# Because emitDCEGraph only considers the main js file, and not worker.js
# we have explicitly mark these symbols as user-exported so that they will
# kept alive through DCE.
# TODO: Find a less hacky way to do this, perhaps by also scanning worker.js
# for roots.
worker_imports = [
'__emscripten_thread_init',
'__emscripten_thread_exit',
'__emscripten_thread_crashed',
'__emscripten_thread_mailbox_await',
'__emscripten_tls_init',
'_pthread_self',
'checkMailbox',
]
if settings.EMBIND:
worker_imports.append('__embind_initialize_bindings')
settings.EXPORTED_FUNCTIONS += worker_imports
building.user_requested_exports.update(worker_imports)
# set location of worker.js
settings.PTHREAD_WORKER_FILE = unsuffixed_basename(target) + '.worker.js'
if settings.MINIMAL_RUNTIME:
building.user_requested_exports.add('exit')
# pthread stack setup and other necessary utilities
def include_and_export(name):
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$' + name]
settings.EXPORTED_FUNCTIONS += [name]
include_and_export('establishStackSpace')
include_and_export('invokeEntryPoint')
include_and_export('PThread')
if not settings.MINIMAL_RUNTIME:
# keepRuntimeAlive does not apply to MINIMAL_RUNTIME.
settings.EXPORTED_RUNTIME_METHODS += ['keepRuntimeAlive', 'ExitStatus', 'wasmMemory']
if settings.MODULARIZE:
if not settings.EXPORT_ES6 and settings.EXPORT_NAME == 'Module':
exit_with_error('pthreads + MODULARIZE currently require you to set -sEXPORT_NAME=Something (see settings.js) to Something != Module, so that the .worker.js file can work')
# MODULARIZE+PTHREADS mode requires extra exports out to Module so that worker.js
# can access them:
# general threading variables:
settings.EXPORTED_RUNTIME_METHODS += ['PThread']
# To keep code size to minimum, MINIMAL_RUNTIME does not utilize the global ExitStatus
# object, only regular runtime has it.
if not settings.MINIMAL_RUNTIME:
settings.EXPORTED_RUNTIME_METHODS += ['ExitStatus']
def set_max_memory():
# When memory growth is disallowed set MAXIMUM_MEMORY equal to INITIAL_MEMORY
if not settings.ALLOW_MEMORY_GROWTH:
if 'MAXIMUM_MEMORY' in user_settings:
diagnostics.warning('unused-command-line-argument', 'MAXIMUM_MEMORY is only meaningful with ALLOW_MEMORY_GROWTH')
settings.MAXIMUM_MEMORY = settings.INITIAL_MEMORY
if 'MAXIMUM_MEMORY' not in user_settings:
if settings.ALLOW_MEMORY_GROWTH and settings.INITIAL_MEMORY > 2 * 1024 * 1024 * 1024:
settings.MAXIMUM_MEMORY = 4 * 1024 * 1024 * 1024
# INITIAL_MEMORY sets a lower bound for MAXIMUM_MEMORY
if settings.INITIAL_MEMORY > settings.MAXIMUM_MEMORY:
settings.MAXIMUM_MEMORY = settings.INITIAL_MEMORY
if settings.MAXIMUM_MEMORY < settings.INITIAL_MEMORY:
exit_with_error('MAXIMUM_MEMORY cannot be less than INITIAL_MEMORY')
@ToolchainProfiler.profile_block('linker_setup')
def phase_linker_setup(options, state, newargs):
system_libpath = '-L' + str(cache.get_lib_dir(absolute=True))
state.add_link_flag(sys.maxsize, system_libpath)
# We used to do this check during on startup during `check_sanity`, but
# we now only do it when linking, in order to reduce the overhead when
# only compiling.
if not shared.SKIP_SUBPROCS:
shared.check_llvm_version()
autoconf = os.environ.get('EMMAKEN_JUST_CONFIGURE') or 'conftest.c' in state.orig_args or 'conftest.cpp' in state.orig_args
if autoconf:
# configure tests want a more shell-like style, where we emit return codes on exit()
settings.EXIT_RUNTIME = 1
# use node.js raw filesystem access, to behave just like a native executable
settings.NODERAWFS = 1
# Add `#!` line to output JS and make it executable.
options.executable = True
if 'noExitRuntime' in settings.INCOMING_MODULE_JS_API:
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE.append('$noExitRuntime')
if settings.OPT_LEVEL >= 1:
default_setting('ASSERTIONS', 0)
if options.emrun:
options.pre_js.append(utils.path_from_root('src/emrun_prejs.js'))
options.post_js.append(utils.path_from_root('src/emrun_postjs.js'))
# emrun mode waits on program exit
settings.EXIT_RUNTIME = 1
if options.cpu_profiler:
options.post_js.append(utils.path_from_root('src/cpuprofiler.js'))
if not settings.RUNTIME_DEBUG:
settings.RUNTIME_DEBUG = bool(settings.LIBRARY_DEBUG or
settings.GL_DEBUG or
settings.DYLINK_DEBUG or
settings.OPENAL_DEBUG or
settings.SYSCALL_DEBUG or
settings.WEBSOCKET_DEBUG or
settings.SOCKET_DEBUG or
settings.FETCH_DEBUG or
settings.EXCEPTION_DEBUG or
settings.PTHREADS_DEBUG or
settings.ASYNCIFY_DEBUG)
if options.memory_profiler:
settings.MEMORYPROFILER = 1
if settings.PTHREADS_PROFILING:
if not settings.ASSERTIONS:
exit_with_error('PTHREADS_PROFILING only works with ASSERTIONS enabled')
options.post_js.append(utils.path_from_root('src/threadprofiler.js'))
options.extern_pre_js = read_js_files(options.extern_pre_js)
options.extern_post_js = read_js_files(options.extern_post_js)
# TODO: support source maps with js_transform
if options.js_transform and settings.GENERATE_SOURCE_MAP:
logger.warning('disabling source maps because a js transform is being done')
settings.GENERATE_SOURCE_MAP = 0
# options.output_file is the user-specified one, target is what we will generate
if options.output_file:
target = options.output_file
# check for the existence of the output directory now, to avoid having
# to do so repeatedly when each of the various output files (.mem, .wasm,
# etc) are written. This gives a more useful error message than the
# IOError and python backtrace that users would otherwise see.
dirname = os.path.dirname(target)
if dirname and not os.path.isdir(dirname):
exit_with_error("specified output file (%s) is in a directory that does not exist" % target)
elif autoconf:
# Autoconf expects the executable output file to be called `a.out`
target = 'a.out'
elif settings.SIDE_MODULE:
target = 'a.out.wasm'
else:
target = 'a.out.js'
final_suffix = get_file_suffix(target)
if settings.EXTRA_EXPORTED_RUNTIME_METHODS:
diagnostics.warning('deprecated', 'EXTRA_EXPORTED_RUNTIME_METHODS is deprecated, please use EXPORTED_RUNTIME_METHODS instead')
settings.EXPORTED_RUNTIME_METHODS += settings.EXTRA_EXPORTED_RUNTIME_METHODS
# If no output format was specified we try to deduce the format based on
# the output filename extension
if not options.oformat and (options.relocatable or (options.shared and not settings.SIDE_MODULE)):
# Until we have a better story for actually producing runtime shared libraries
# we support a compatibility mode where shared libraries are actually just
# object files linked with `wasm-ld --relocatable` or `llvm-link` in the case
# of LTO.
if final_suffix in EXECUTABLE_ENDINGS:
diagnostics.warning('emcc', '-shared/-r used with executable output suffix. This behaviour is deprecated. Please remove -shared/-r to build an executable or avoid the executable suffix (%s) when building object files.' % final_suffix)
else:
if options.shared:
diagnostics.warning('emcc', 'linking a library with `-shared` will emit a static object file. This is a form of emulation to support existing build systems. If you want to build a runtime shared library use the SIDE_MODULE setting.')
options.oformat = OFormat.OBJECT
if not options.oformat:
if settings.SIDE_MODULE or final_suffix == '.wasm':
options.oformat = OFormat.WASM
elif final_suffix == '.mjs':
options.oformat = OFormat.MJS
elif final_suffix == '.html':
options.oformat = OFormat.HTML
else:
options.oformat = OFormat.JS
if options.oformat == OFormat.MJS:
settings.EXPORT_ES6 = 1
settings.MODULARIZE = 1
if options.oformat in (OFormat.WASM, OFormat.BARE):
# If the user asks directly for a wasm file then this *is* the target
wasm_target = target
else:
# Otherwise the wasm file is produced alongside the final target.
wasm_target = get_secondary_target(target, '.wasm')
if settings.SAFE_HEAP not in [0, 1, 2]:
exit_with_error('emcc: SAFE_HEAP must be 0, 1 or 2')
if not settings.WASM:
# When the user requests non-wasm output, we enable wasm2js. that is,
# we still compile to wasm normally, but we compile the final output
# to js.
settings.WASM = 1
settings.WASM2JS = 1
if settings.WASM == 2:
# Requesting both Wasm and Wasm2JS support
settings.WASM2JS = 1
if options.oformat == OFormat.WASM and not settings.SIDE_MODULE:
# if the output is just a wasm file, it will normally be a standalone one,
# as there is no JS. an exception are side modules, as we can't tell at
# compile time whether JS will be involved or not - the main module may
# have JS, and the side module is expected to link against that.
# we also do not support standalone mode in fastcomp.
settings.STANDALONE_WASM = 1
if settings.LZ4:
settings.EXPORTED_RUNTIME_METHODS += ['LZ4']
if settings.PURE_WASI:
settings.STANDALONE_WASM = 1
settings.WASM_BIGINT = 1
if options.no_entry:
settings.EXPECT_MAIN = 0
elif settings.STANDALONE_WASM:
if '_main' in settings.EXPORTED_FUNCTIONS:
# TODO(sbc): Make this into a warning?
logger.debug('including `_main` in EXPORTED_FUNCTIONS is not necessary in standalone mode')
else:
# In normal non-standalone mode we have special handling of `_main` in EXPORTED_FUNCTIONS.
# 1. If the user specifies exports, but doesn't include `_main` we assume they want to build a
# reactor.
# 2. If the user doesn't export anything we default to exporting `_main` (unless `--no-entry`
# is specified (see above).
if 'EXPORTED_FUNCTIONS' in user_settings:
if '_main' not in settings.USER_EXPORTED_FUNCTIONS:
settings.EXPECT_MAIN = 0
else:
assert not settings.EXPORTED_FUNCTIONS
settings.EXPORTED_FUNCTIONS = ['_main']
if settings.STANDALONE_WASM:
# In STANDALONE_WASM mode we either build a command or a reactor.
# See https://github.com/WebAssembly/WASI/blob/main/design/application-abi.md
# For a command we always want EXIT_RUNTIME=1
# For a reactor we always want EXIT_RUNTIME=0
if 'EXIT_RUNTIME' in user_settings:
exit_with_error('Explicitly setting EXIT_RUNTIME not compatible with STANDALONE_WASM. EXIT_RUNTIME will always be True for programs (with a main function) and False for reactors (not main function).')
settings.EXIT_RUNTIME = settings.EXPECT_MAIN
settings.IGNORE_MISSING_MAIN = 0
# the wasm must be runnable without the JS, so there cannot be anything that
# requires JS legalization
settings.LEGALIZE_JS_FFI = 0
if 'MEMORY_GROWTH_LINEAR_STEP' in user_settings:
exit_with_error('MEMORY_GROWTH_LINEAR_STEP is not compatible with STANDALONE_WASM')
if 'MEMORY_GROWTH_GEOMETRIC_CAP' in user_settings:
exit_with_error('MEMORY_GROWTH_GEOMETRIC_CAP is not compatible with STANDALONE_WASM')
if settings.MINIMAL_RUNTIME:
exit_with_error('MINIMAL_RUNTIME reduces JS size, and is incompatible with STANDALONE_WASM which focuses on ignoring JS anyhow and being 100% wasm')
# Note the exports the user requested
building.user_requested_exports.update(settings.EXPORTED_FUNCTIONS)
if '_main' in settings.EXPORTED_FUNCTIONS:
settings.EXPORT_IF_DEFINED.append('__main_argc_argv')
elif settings.ASSERTIONS and not settings.STANDALONE_WASM:
# In debug builds when `main` is not explicitly requested as an
# export we still add it to EXPORT_IF_DEFINED so that we can warn
# users who forget to explicitly export `main`.
# See other.test_warn_unexported_main.
# This is not needed in STANDALONE_WASM mode since we export _start
# (unconditionally) rather than main.
settings.EXPORT_IF_DEFINED.append('main')
if settings.ASSERTIONS:
# Exceptions are thrown with a stack trace by default when ASSERTIONS is
# set and when building with either -fexceptions or -fwasm-exceptions.
if 'EXCEPTION_STACK_TRACES' in user_settings and not settings.EXCEPTION_STACK_TRACES:
exit_with_error('EXCEPTION_STACK_TRACES cannot be disabled when ASSERTIONS are enabled')
if settings.WASM_EXCEPTIONS or not settings.DISABLE_EXCEPTION_CATCHING:
settings.EXCEPTION_STACK_TRACES = 1
# -sASSERTIONS implies basic stack overflow checks, and ASSERTIONS=2
# implies full stack overflow checks. However, we don't set this default in
# PURE_WASI, or when we are linking without standard libraries because
# STACK_OVERFLOW_CHECK depends on emscripten_stack_get_end which is defined
# in libcompiler-rt.
if not settings.PURE_WASI and '-nostdlib' not in newargs and '-nodefaultlibs' not in newargs:
default_setting('STACK_OVERFLOW_CHECK', max(settings.ASSERTIONS, settings.STACK_OVERFLOW_CHECK))
# For users that opt out of WARN_ON_UNDEFINED_SYMBOLS we assume they also
# want to opt out of ERROR_ON_UNDEFINED_SYMBOLS.
if user_settings.get('WARN_ON_UNDEFINED_SYMBOLS') == '0':
default_setting('ERROR_ON_UNDEFINED_SYMBOLS', 0)
# It is unlikely that developers targeting "native web" APIs with MINIMAL_RUNTIME need
# errno support by default.
if settings.MINIMAL_RUNTIME:
default_setting('SUPPORT_ERRNO', 0)
# Require explicit -lfoo.js flags to link with JS libraries.
default_setting('AUTO_JS_LIBRARIES', 0)
# When using MINIMAL_RUNTIME, symbols should only be exported if requested.
default_setting('EXPORT_KEEPALIVE', 0)
if settings.STRICT_JS and (settings.MODULARIZE or settings.EXPORT_ES6):
exit_with_error("STRICT_JS doesn't work with MODULARIZE or EXPORT_ES6")
if not options.shell_path:
# Minimal runtime uses a different default shell file
if settings.MINIMAL_RUNTIME:
options.shell_path = options.shell_path = utils.path_from_root('src/shell_minimal_runtime.html')
else:
options.shell_path = DEFAULT_SHELL_HTML
if settings.STRICT:
if not settings.MODULARIZE and not settings.EXPORT_ES6:
default_setting('STRICT_JS', 1)
default_setting('DEFAULT_TO_CXX', 0)
default_setting('AUTO_JS_LIBRARIES', 0)
default_setting('AUTO_NATIVE_LIBRARIES', 0)
default_setting('AUTO_ARCHIVE_INDEXES', 0)
default_setting('IGNORE_MISSING_MAIN', 0)
default_setting('ALLOW_UNIMPLEMENTED_SYSCALLS', 0)
if options.oformat == OFormat.HTML and options.shell_path == DEFAULT_SHELL_HTML:
# Out default shell.html file has minimal set of INCOMING_MODULE_JS_API elements that it expects
default_setting('INCOMING_MODULE_JS_API', 'canvas,monitorRunDependencies,onAbort,onExit,print,setStatus'.split(','))
else:
default_setting('INCOMING_MODULE_JS_API', [])
if 'GLOBAL_BASE' not in user_settings and not settings.SHRINK_LEVEL and not settings.OPT_LEVEL:
# When optimizing for size it helps to put static data first before
# the stack (sincs this makes instructions for accessing this data
# use a smaller LEB encoding).
# However, for debugability is better to have the stack come first
# (becuase stack overflows will trap rather than corrupting data).
settings.STACK_FIRST = True
# Default to TEXTDECODER=2 (always use TextDecoder to decode UTF-8 strings)
# in -Oz builds, since custom decoder for UTF-8 takes up space.
# In pthreads enabled builds, TEXTDECODER==2 may not work, see
# https://github.com/whatwg/encoding/issues/172
# When supporting shell environments, do not do this as TextDecoder is not
# widely supported there.
if settings.SHRINK_LEVEL >= 2 and not settings.SHARED_MEMORY and \
not settings.ENVIRONMENT_MAY_BE_SHELL:
default_setting('TEXTDECODER', 2)
# If set to 1, we will run the autodebugger (the automatic debugging tool, see
# tools/autodebugger). Note that this will disable inclusion of libraries. This
# is useful because including dlmalloc makes it hard to compare native and js
# builds
if os.environ.get('EMCC_AUTODEBUG'):
settings.AUTODEBUG = 1
# Use settings
if settings.DEBUG_LEVEL > 1 and options.use_closure_compiler:
diagnostics.warning('emcc', 'disabling closure because debug info was requested')
options.use_closure_compiler = False
if settings.WASM == 2 and settings.SINGLE_FILE:
exit_with_error('cannot have both WASM=2 and SINGLE_FILE enabled at the same time')
if settings.SEPARATE_DWARF and settings.WASM2JS:
exit_with_error('cannot have both SEPARATE_DWARF and WASM2JS at the same time (as there is no wasm file)')
if settings.MINIMAL_RUNTIME_STREAMING_WASM_COMPILATION and settings.MINIMAL_RUNTIME_STREAMING_WASM_INSTANTIATION:
exit_with_error('MINIMAL_RUNTIME_STREAMING_WASM_COMPILATION and MINIMAL_RUNTIME_STREAMING_WASM_INSTANTIATION are mutually exclusive!')
if options.emrun:
if settings.MINIMAL_RUNTIME:
exit_with_error('--emrun is not compatible with MINIMAL_RUNTIME')
if options.use_closure_compiler:
settings.USE_CLOSURE_COMPILER = 1
if 'CLOSURE_WARNINGS' in user_settings:
if settings.CLOSURE_WARNINGS not in ['quiet', 'warn', 'error']:
exit_with_error('Invalid option -sCLOSURE_WARNINGS=%s specified! Allowed values are "quiet", "warn" or "error".' % settings.CLOSURE_WARNINGS)
diagnostics.warning('deprecated', 'CLOSURE_WARNINGS is deprecated, use -Wclosure/-Wno-closure instread')
closure_warnings = diagnostics.manager.warnings['closure']
if settings.CLOSURE_WARNINGS == 'error':
closure_warnings['error'] = True
closure_warnings['enabled'] = True
elif settings.CLOSURE_WARNINGS == 'warn':
closure_warnings['error'] = False
closure_warnings['enabled'] = True
elif settings.CLOSURE_WARNINGS == 'quiet':
closure_warnings['error'] = False
closure_warnings['enabled'] = False
if not settings.MINIMAL_RUNTIME:
if not settings.BOOTSTRAPPING_STRUCT_INFO:
if settings.DYNCALLS:
# Include dynCall() function by default in DYNCALLS builds in classic runtime; in MINIMAL_RUNTIME, must add this explicitly.
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$dynCall']
if settings.ASSERTIONS:
# "checkUnflushedContent()" and "missingLibrarySymbol()" depend on warnOnce
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$warnOnce']
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$getValue', '$setValue']
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$ExitStatus']
if not settings.BOOTSTRAPPING_STRUCT_INFO and settings.SAFE_HEAP:
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$getValue_safe', '$setValue_safe']
if settings.ABORT_ON_WASM_EXCEPTIONS or settings.SPLIT_MODULE:
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$wasmTable']
if settings.MAIN_MODULE:
assert not settings.SIDE_MODULE
if settings.MAIN_MODULE == 1:
settings.INCLUDE_FULL_LIBRARY = 1
# Called from preamble.js once the main module is instantiated.
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$loadDylibs']
if settings.MAIN_MODULE == 1 or settings.SIDE_MODULE == 1:
settings.LINKABLE = 1
if settings.LINKABLE and settings.USER_EXPORTED_FUNCTIONS:
diagnostics.warning('unused-command-line-argument', 'EXPORTED_FUNCTIONS is not valid with LINKABLE set (normally due to SIDE_MODULE=1/MAIN_MODULE=1) since all functions are exported this mode. To export only a subset use SIDE_MODULE=2/MAIN_MODULE=2')
if settings.MAIN_MODULE:
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += [
'$getDylinkMetadata',
'$mergeLibSymbols',
]
if settings.PTHREADS:
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += [
'$registerTLSInit',
]
if settings.RELOCATABLE:
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += [
'$reportUndefinedSymbols',
'$relocateExports',
'$GOTHandler',
'__heap_base',
'__stack_pointer',
]
if settings.ASYNCIFY == 1:
settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += [
'__asyncify_state',