blob: c9e2a5df30b23de0e28fbb9672bcc1e0e638e4f3 [file] [log] [blame]
#!/usr/bin/env python2
# 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.
"""emcc - compiler helper script
emcc is a drop-in replacement for a compiler like gcc or clang.
See emcc --help for details.
emcc can be influenced by a few environment variables:
EMCC_DEBUG - "1" will log out useful information during compilation, as well as
save each compiler step as an emcc-* file in the temp dir
(by default /tmp/emscripten_temp). "2" will save additional emcc-*
steps, that would normally not be separately produced (so this
slows down compilation).
EMMAKEN_NO_SDK - Will tell emcc *not* to use the emscripten headers. Instead
your system headers will be used.
EMMAKEN_COMPILER - The compiler to be used, if you don't want the default clang.
from __future__ import print_function
import json
import logging
import os
import re
import shlex
import shutil
import stat
import sys
import time
from subprocess import PIPE
from tools import shared, system_libs, client_mods, js_optimizer, jsrun
from tools.shared import unsuffixed, unsuffixed_basename, WINDOWS, safe_copy, safe_move, run_process, asbytes, read_and_preprocess, exit_with_error, DEBUG
from tools.response_file import substitute_response_files
import tools.line_endings
from tools.toolchain_profiler import ToolchainProfiler
if __name__ == '__main__':
from urllib.parse import quote
except ImportError:
# Python 2 compatibility
from urllib import quote
logger = logging.getLogger('emcc')
# endings = dot + a suffix, safe to test by filename.endswith(endings)
C_ENDINGS = ('.c', '.C', '.i')
CXX_ENDINGS = ('.cpp', '.cxx', '.cc', '.c++', '.CPP', '.CXX', '.CC', '.C++', '.ii')
OBJC_ENDINGS = ('.m', '.mi')
OBJCXX_ENDINGS = ('.mm', '.mii')
C_ENDINGS = C_ENDINGS + SPECIAL_ENDINGLESS_FILENAMES # consider the special endingless filenames like /dev/null to be C
JS_CONTAINING_ENDINGS = ('.js', '.mjs', '.html')
BITCODE_ENDINGS = ('.bc', '.o', '.obj', '.lo')
DYNAMICLIB_ENDINGS = ('.dylib', '.so') # Windows .dll suffix is not included in this list, since those are never linked to directly on the command line.
HEADER_ENDINGS = ('.h', '.hxx', '.hpp', '.hh', '.H', '.HXX', '.HPP', '.HH')
WASM_ENDINGS = ('.wasm', '.wast')
'--start-group', '--end-group',
'-(', '-)',
'--whole-archive', '--no-whole-archive',
'-whole-archive', '-no-whole-archive')
LIB_PREFIXES = ('', 'lib')
# Mapping of emcc opt levels to llvm opt levels. We use llvm opt level 3 in emcc
# opt levels 2 and 3 (emcc 3 is unsafe opts, so unsuitable for the only level to
# get llvm opt level 3, and speed-wise emcc level 2 is already the slowest/most
# optimizing level)
0: ['-O0'],
1: ['-O1'],
2: ['-O3'],
3: ['-O3'],
# Do not compile .ll files into .bc, just compile them with emscripten directly
# Not recommended, this is mainly for the test runner, or if you have some other
# specific need.
# One major limitation with this mode is that libc and libc++ cannot be
# added in. Also, LLVM optimizations will not be done, nor dead code elimination
LEAVE_INPUTS_RAW = int(os.environ.get('EMCC_LEAVE_INPUTS_RAW', '0'))
# If emcc is running with LEAVE_INPUTS_RAW and then launches an emcc to build
# something like the struct info, then we don't want LEAVE_INPUTS_RAW to be
# active in that emcc subprocess.
del os.environ['EMCC_LEAVE_INPUTS_RAW']
# 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
AUTODEBUG = os.environ.get('EMCC_AUTODEBUG')
# Target options
final = None
class Intermediate(object):
counter = 0
# 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:
name = os.path.join(shared.get_emscripten_temp_dir(), 'emcc-%d-%s.%s' % (Intermediate.counter, name, suffix))
if isinstance(final, list):
logger.debug('(not saving intermediate %s because deferring linking)' % name)
shutil.copyfile(final, name)
Intermediate.counter += 1
def save_intermediate_with_wasm(name, wasm_binary):
if not DEBUG:
save_intermediate(name) # save the js
name = os.path.join(shared.get_emscripten_temp_dir(), 'emcc-%d-%s.wasm' % (Intermediate.counter - 1, name))
shutil.copyfile(wasm_binary, name)
class TimeLogger(object):
last = time.time()
def update():
TimeLogger.last = time.time()
def log_time(name):
"""Log out times for emcc stages"""
now = time.time()
logger.debug('emcc step "%s" took %.2f seconds', name, now - TimeLogger.last)
class EmccOptions(object):
def __init__(self):
self.opt_level = 0
self.debug_level = 0
self.shrink_level = 0
self.requested_debug = ''
self.profiling = False
self.profiling_funcs = False
self.tracing = False
self.emit_symbol_map = False
self.js_opts = None
self.force_js_opts = False
self.llvm_opts = None
self.llvm_lto = None
self.default_cxx_std = '-std=c++03' # Enforce a consistent C++ standard when compiling .cpp files, if user does not specify one on the cmdline.
self.use_closure_compiler = None
self.js_transform = None
self.pre_js = '' # before all js
self.post_js = '' # after all js
self.preload_files = []
self.embed_files = []
self.exclude_files = []
self.ignore_dynamic_linking = False
self.shell_path = shared.path_from_root('src', 'shell.html')
self.source_map_base = ''
self.js_libraries = []
self.bind = False
self.emrun = False
self.cpu_profiler = False
self.thread_profiler = False
self.memory_profiler = False
self.save_bc = False
self.memory_init_file = None
self.use_preload_cache = False
self.no_heap_copy = False
self.use_preload_plugins = False
self.proxy_to_worker = False
self.default_object_extension = '.o'
self.valid_abspaths = []
self.separate_asm = False
self.cfi = False
# Specifies the line ending format to use for all generated text files.
# Defaults to using the native EOL on each platform (\r\n on Windows, \n on
# Linux & MacOS)
self.output_eol = os.linesep
def use_source_map(options):
return options.debug_level >= 4
def will_metadce(options):
return options.opt_level >= 3 or options.shrink_level >= 1
class JSOptimizer(object):
def __init__(self, target, options, js_transform_tempfiles, in_temp):
self.queue = []
self.extra_info = {}
self.queue_history = []
self.blacklist = os.environ.get('EMCC_JSOPT_BLACKLIST', '').split(',')
self.minify_whitespace = False
self.cleanup_shell = False = target
self.opt_level = options.opt_level
self.debug_level = options.debug_level
self.emit_symbol_map = options.emit_symbol_map
self.profiling_funcs = options.profiling_funcs
self.use_closure_compiler = options.use_closure_compiler
self.js_transform_tempfiles = js_transform_tempfiles
self.in_temp = in_temp
def flush(self, title='js_opts'):
self.queue = [p for p in self.queue if p not in self.blacklist]
assert not shared.Settings.WASM_BACKEND, 'JSOptimizer should not run with pure wasm output'
if self.extra_info is not None and len(self.extra_info) == 0:
self.extra_info = None
if len(self.queue) and not(not shared.Settings.ASM_JS and len(self.queue) == 1 and self.queue[0] == 'last'):
passes = self.queue[:]
if DEBUG != 2 or len(passes) < 2:
# by assumption, our input is JS, and our output is JS. If a pass is going to run in the native optimizer in C++, then we
# must give it JSON and receive from it JSON
chunks = []
curr = []
for p in passes:
if len(curr) == 0:
native = js_optimizer.use_native(p, source_map=use_source_map(self))
last_native = js_optimizer.use_native(curr[-1], source_map=use_source_map(self))
if native == last_native:
curr = ['receiveJSON', p]
if len(curr):
if len(chunks) == 1:
self.run_passes(chunks[0], title, just_split=False, just_concat=False)
for i, chunk in enumerate(chunks):
self.run_passes(chunk, 'js_opts_' + str(i),
just_split='receiveJSON' in chunk,
just_concat='emitJSON' in chunk)
# DEBUG 2, run each pass separately
extra_info = self.extra_info
for p in passes:
self.queue = [p]
self.extra_info = extra_info # flush wipes it
log_time('part of js opts')
self.queue_history += self.queue
self.queue = []
self.extra_info = {}
def run_passes(self, passes, title, just_split, just_concat):
global final
passes = ['asm'] + passes
if shared.Settings.PRECISE_F32:
passes = ['asmPreciseF32'] + passes
if (self.emit_symbol_map or shared.Settings.CYBERDWARF) and 'minifyNames' in passes:
passes += ['symbolMap=' + + '.symbols']
if self.profiling_funcs and 'minifyNames' in passes:
passes += ['profilingFuncs']
if self.minify_whitespace and 'last' in passes:
passes += ['minifyWhitespace']
if self.cleanup_shell and 'last' in passes:
passes += ['cleanup']
logger.debug('applying js optimization passes: %s', ' '.join(passes))
final = shared.Building.js_optimizer(final, passes, use_source_map(self),
self.extra_info, just_split=just_split,
output_filename=self.in_temp(os.path.basename(final) + '.jsopted.js'))
save_intermediate(title, suffix='js' if 'emitJSON' not in passes else 'json')
def do_minify(self):
"""minifies the code.
this is also when we do certain optimizations that must be done right before or after minification
if self.opt_level >= 2:
if self.debug_level < 2 and not self.use_closure_compiler == 2:
self.queue += ['minifyNames']
if self.debug_level == 0:
self.minify_whitespace = True
if self.use_closure_compiler == 1:
self.queue += ['closure']
elif self.debug_level <= 2 and shared.Settings.FINALIZE_ASM_JS and not self.use_closure_compiler:
self.cleanup_shell = True
def embed_memfile(options):
return shared.Settings.SINGLE_FILE or (shared.Settings.MEM_INIT_METHOD == 0 and (not shared.Settings.MAIN_MODULE and not shared.Settings.SIDE_MODULE and not use_source_map(options)))
def apply_settings(changes):
"""Take a list of settings in form `NAME=VALUE` and apply them to the global
Settings object.
def standardize_setting_change(key, value):
# Handle aliases in settings flags. These are settings whose name
# has changed.
settings_aliases = {
# TODO: change most (all?) other BINARYEN* names to WASM*
key = settings_aliases.get(key, key)
# boolean NO_X settings are aliases for X
# (note that *non*-boolean setting values have special meanings,
# and we can't just flip them, so leave them as-is to be
# handled in a special way later)
if key.startswith('NO_') and value in ('0', '1'):
key = key[3:]
value = str(1 - int(value))
return key, value
for change in changes:
key, value = change.split('=', 1)
key, value = standardize_setting_change(key, value)
# In those settings fields that represent amount of memory, translate suffixes to multiples of 1024.
value = str(shared.expand_byte_size_suffixes(value))
if value[0] == '@':
value = open(value[1:]).read()
value = value.replace('\\', '\\\\')
setattr(shared.Settings, key, parse_value(value))
except Exception as e:
exit_with_error('a problem occured in evaluating the content after a "-s", specifically "%s": %s', change, str(e))
# used for warnings in
def find_output_arg(args):
"""Find and remove any -o arguments. The final one takes precedence.
Return the final -o target along with the remaining (non-o) arguments.
outargs = []
specified_target = None
use_next = False
for arg in args:
if use_next:
specified_target = arg
use_next = False
if arg == '-o':
use_next = True
elif arg.startswith('-o'):
specified_target = arg[2:]
return specified_target, outargs
# Main run() function
def run(args):
global final
target = None
# Additional compiler flags that we treat as if they were passed to us on the
# commandline
EMCC_CFLAGS = os.environ.get('EMCC_CFLAGS')
cmd = ' '.join(args)
cmd += ' + ' + EMCC_CFLAGS
logger.warning('invocation: ' + cmd + ' (in ' + os.getcwd() + ')')
# Strip args[0] (program name)
args = args[1:]
logger.warning('leaving inputs raw')
if '--emscripten-cxx' in args:
run_via_emxx = True
args = [x for x in args if x != '--emscripten-cxx']
run_via_emxx = False
misc_temp_files = shared.configuration.get_temp_files()
# Handle some global flags
# read response files very early on
args = substitute_response_files(args)
if '--help' in args:
# Documentation for emcc and its options must be updated in:
# site/source/docs/tools_reference/emcc.rst
# A prebuilt local version of the documentation is available at:
# site/build/text/docs/tools_reference/emcc.txt
# (it is read from there and printed out when --help is invoked)
# You can also build docs locally as HTML or other formats in site/
# An online HTML version (which may be of a different version of Emscripten)
# is up at
emcc: supported targets: llvm bitcode, javascript, NOT elf
(autoconf likes to see elf above to enable shared object support)
''' % (open(shared.path_from_root('site', 'build', 'text', 'docs', 'tools_reference', 'emcc.txt')).read()))
return 0
if '--version' in args:
revision = '(unknown revision)'
here = os.getcwd()
revision = run_process(['git', 'show'], stdout=PIPE, stderr=PIPE).stdout.split('\n')[0]
print('''emcc (Emscripten gcc/clang-like replacement) %s (%s)
Copyright (C) 2014 the Emscripten authors (see AUTHORS.txt)
This is free and open source software under the MIT license.
''' % (shared.EMSCRIPTEN_VERSION, revision))
return 0
if len(args) == 1 and args[0] == '-v': # -v with no inputs
# autoconf likes to see 'GNU' in the output to enable shared object support
print('emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) %s' % shared.EMSCRIPTEN_VERSION, file=sys.stderr)
code = run_process([shared.CLANG_CC, '-v'], check=False).returncode
return code
# This check comes after check_sanity because test_sanity expects this.
if not args:
logger.warning('no input files')
return 1
if '-dumpmachine' in args:
return 0
if '-dumpversion' in args: # gcc's doc states "Print the compiler version [...] and don't do anything else."
return 0
if '--cflags' in args:
# fake running the command, to see the full args we pass to clang
debug_env = os.environ.copy()
debug_env['EMCC_DEBUG'] = '1'
args = [x for x in args if x != '--cflags']
with misc_temp_files.get_file(suffix='.o') as temp_target:
input_file = 'hello_world.c'
err = run_process([shared.PYTHON, sys.argv[0]] + args + [shared.path_from_root('tests', input_file), '-c', '-o', temp_target], stderr=PIPE, env=debug_env).stderr
lines = [x for x in err.split('\n') if shared.CLANG_CC in x and input_file in x]
line ='running: (.*)', lines[0]).group(1)
parts = shlex.split(line.replace('\\', '\\\\'))
parts = [x for x in parts if x != '-c' and x != '-o' and input_file not in x and temp_target not in x and '-emit-llvm' not in x]
print(' '.join(shared.Building.doublequote_spaces(parts[1:])))
return 0
# Default to using C++ even when run as `emcc`.
# This means that emcc will act as a C++ linker when no source files are
# specified. However, when a C source is specified we do default to C.
# This differs to clang and gcc where the default is always C unless run as
# clang++/g++.
use_cxx = True
def get_language_mode(args):
return_next = False
for item in args:
if return_next:
return item
if item == '-x':
return_next = True
if item.startswith('-x'):
return item[2:]
return None
def has_c_source(args):
for a in args:
if a[0] != '-' and a.endswith(C_ENDINGS + OBJC_ENDINGS):
return True
return False
language_mode = get_language_mode(args)
has_fixed_language_mode = language_mode is not None
if language_mode == 'c':
use_cxx = False
if not has_fixed_language_mode:
if not run_via_emxx and has_c_source(args):
use_cxx = False
def is_minus_s_for_emcc(args, i):
# -s OPT=VALUE or -s OPT are interpreted as emscripten flags.
# -s by itself is a linker option (alias for --strip-all)
assert args[i] == '-s'
if len(args) > i + 1:
arg = args[i + 1]
if arg.split('=')[0].isupper():
return True
logger.debug('treating -s as linker option and not as -s OPT=VALUE for js compilation')
return False
# If this is a configure-type thing, do not compile to JavaScript, instead use clang
# to compile to a native binary (using our headers, so things make sense later)
CONFIGURE_CONFIG = (os.environ.get('EMMAKEN_JUST_CONFIGURE') or 'conftest.c' in args) and not os.environ.get('EMMAKEN_JUST_CONFIGURE_RECURSE')
CMAKE_CONFIG = 'CMakeFiles/cmTryCompileExec.dir' in ' '.join(args)# or 'CMakeCCompilerId' in ' '.join(args)
# XXX use this to debug configure stuff. ./configure's generally hide our
# normal output including stderr so we write to a file
debug_configure = 0
# Whether we fake configure tests using clang - the local, native compiler -
# or not. if not we generate JS and use node with a shebang
# Neither approach is perfect, you can try both, but may need to edit
# configure scripts in some cases
# By default we configure in js, which can break on local filesystem access,
# etc., but is otherwise accurate so we
# disable this if we think we have to. A value of '2' here will force JS
# checks in all cases. In summary:
# 0 - use native compilation for configure checks
# 1 - use js when we think it will work
# 2 - always use js for configure checks
use_js = int(os.environ.get('EMCONFIGURE_JS') or 2)
if debug_configure:
tempout = '/tmp/emscripten_temp/out'
if not os.path.exists(tempout):
open(tempout, 'w').write('//\n')
src = None
for arg in args:
if arg.endswith(SOURCE_ENDINGS):
src = open(arg).read()
if debug_configure:
open(tempout, 'a').write('============= ' + arg + '\n' + src + '\n=============\n\n')
elif arg.endswith('.s'):
if debug_configure:
open(tempout, 'a').write('(compiling .s assembly, must use clang\n')
if use_js == 1:
use_js = 0
elif arg == '-E' or arg == '-M' or arg == '-MM':
if use_js == 1:
use_js = 0
if src:
if 'fopen' in src and '"w"' in src:
if use_js == 1:
use_js = 0 # we cannot write to files from js!
if debug_configure:
open(tempout, 'a').write('Forcing clang since uses fopen to write\n')
# if CONFIGURE_CC is defined, use that. let's you use local gcc etc. if you need that
compiler = os.environ.get('CONFIGURE_CC')
if not compiler:
compiler = shared.EMXX if use_js else shared.CLANG_CPP
if 'CXXCompiler' not in ' '.join(args) and not use_cxx:
compiler = shared.to_cc(compiler)
def filter_emscripten_options(argv):
idx = 0
skip_next = False
for el in argv:
if skip_next:
skip_next = False
idx += 1
if not use_js and el == '-s' and is_minus_s_for_emcc(argv, idx): # skip -s X=Y if not using js for configure
skip_next = True
if not use_js and el == '--tracing':
yield el
idx += 1
if compiler in (shared.EMCC, shared.EMXX):
compiler = [shared.PYTHON, compiler]
compiler = [compiler]
cmd = compiler + list(filter_emscripten_options(args))
if not use_js:
cmd += shared.EMSDK_OPTS + ['-D__EMSCRIPTEN__']
# The preprocessor define EMSCRIPTEN is deprecated. Don't pass it to code
# in strict mode. Code should use the define __EMSCRIPTEN__ instead.
if not shared.Settings.STRICT:
cmd += ['-DEMSCRIPTEN']
if use_js:
# configure tests want a more shell-like style, where we emit return codes on exit()
cmd += ['-s', 'NO_EXIT_RUNTIME=0']
# use node.js raw filesystem access, to behave just like a native executable
cmd += ['-s', 'NODERAWFS=1']
# Disable wasm in configuration checks so that (1) we do not depend on
# wasm support just for configuration (perhaps the user does not intend
# to build to wasm; using asm.js only depends on js which we need anyhow),
# and (2) we don't have issues with a separate .wasm file
# on the side, async startup, etc..
if not shared.Settings.WASM_BACKEND:
cmd += ['-s', 'WASM=0']
logger.debug('just configuring: ' + ' '.join(cmd))
if debug_configure:
open(tempout, 'a').write('emcc, just configuring: ' + ' '.join(cmd) + '\n\n')
if not use_js:
return run_process(cmd, check=False).returncode
only_object = '-c' in cmd
for i in reversed(range(len(cmd) - 1)): # Last -o directive should take precedence, if multiple are specified
if cmd[i] == '-o':
if not only_object:
cmd[i + 1] += '.js'
target = cmd[i + 1]
if not target:
target = 'a.out.js'
ret = run_process(cmd, check=False).returncode
if not os.path.exists(target):
# note that emcc -c will cause target to have the wrong value here;
# but then, we don't care about bitcode outputs anyhow, below, so
# skipping returning early is fine
return ret
if target.endswith('.js'):
shutil.copyfile(target, unsuffixed(target))
target = unsuffixed(target)
if not target.endswith(BITCODE_ENDINGS):
src = open(target).read()
full_node = ' '.join(shared.NODE_JS)
if os.path.sep not in full_node:
full_node = '/usr/bin/' + full_node # TODO: use whereis etc. And how about non-*NIX?
open(target, 'w').write('#!' + full_node + '\n' + src) # add shebang
os.chmod(target, stat.S_IMODE(os.stat(target).st_mode) | stat.S_IXUSR) # make executable
pass # can fail if e.g. writing the executable to /dev/null
return ret
CXX = os.environ.get('EMMAKEN_COMPILER', shared.CLANG_CPP)
CC = shared.to_cc(CXX)
args += shlex.split(EMMAKEN_CFLAGS)
# ---------------- Utilities ---------------
def suffix(name):
"""Return the file extension"""
return os.path.splitext(name)[1]
seen_names = {}
def uniquename(name):
if name not in seen_names:
seen_names[name] = str(len(seen_names))
return unsuffixed(name) + '_' + seen_names[name] + suffix(name)
# ---------------- End configs -------------
# Check if a target is specified on the command line
specified_target, args = find_output_arg(args)
# specified_target is the user-specified one, target is what we will generate
if specified_target:
target = specified_target
target = 'a.out.js'
shared.Settings.TARGET_BASENAME = target_basename = unsuffixed_basename(target)
final_suffix = suffix(target)
temp_dir = shared.get_emscripten_temp_dir()
def in_temp(name):
return os.path.join(temp_dir, os.path.basename(name))
def get_file_suffix(filename):
"""Parses the essential suffix of a filename, discarding Unix-style version
numbers in the name. For example for '' returns '.so'"""
return filename
while filename:
filename, suffix = os.path.splitext(filename)
if not suffix[1:].isdigit():
return suffix
return ''
def optimizing(opts):
return '-O0' not in opts
with ToolchainProfiler.profile_block('parse arguments and setup'):
## Parse args
newargs = list(args)
# Scan and strip emscripten specific cmdline warning flags.
# This needs to run before other cmdline flags have been parsed, so that
# warnings are properly printed during arg parse.
newargs = shared.WarningManager.capture_warnings(newargs)
for i in range(len(newargs)):
if newargs[i] in ('-l', '-L', '-I'):
# Scan for individual -l/-L/-I arguments and concatenate the next arg on
# if there is no suffix
newargs[i] += newargs[i + 1]
newargs[i + 1] = ''
options, settings_changes, newargs = parse_args(newargs)
if use_cxx:
clang_compiler = CXX
# If user did not specify a default -std for C++ code, specify the emscripten default.
if options.default_cxx_std:
newargs += [options.default_cxx_std]
# Compiling C code with .c files, don't enforce a default C++ std.
clang_compiler = CC
if options.emrun:
options.pre_js += open(shared.path_from_root('src', 'emrun_prejs.js')).read() + '\n'
options.post_js += open(shared.path_from_root('src', 'emrun_postjs.js')).read() + '\n'
# emrun mode waits on program exit
shared.Settings.EXIT_RUNTIME = 1
if options.cpu_profiler:
options.post_js += open(shared.path_from_root('src', 'cpuprofiler.js')).read() + '\n'
if options.memory_profiler:
options.post_js += open(shared.path_from_root('src', 'memoryprofiler.js')).read() + '\n'
if options.thread_profiler:
options.post_js += open(shared.path_from_root('src', 'threadprofiler.js')).read() + '\n'
if options.js_opts is None:
options.js_opts = options.opt_level >= 2
if options.llvm_opts is None:
options.llvm_opts = LLVM_OPT_LEVEL[options.opt_level]
elif type(options.llvm_opts) == int:
options.llvm_opts = ['-O%d' % options.llvm_opts]
if options.memory_init_file is None:
options.memory_init_file = options.opt_level >= 2
# TODO: support source maps with js_transform
if options.js_transform and use_source_map(options):
logger.warning('disabling source maps because a js transform is being done')
options.debug_level = 3
start_time = time.time() # done after parsing arguments, which might affect debug state
for i in range(len(newargs)):
if newargs[i] == '-s':
if is_minus_s_for_emcc(newargs, i):
key = newargs[i + 1]
# If not = is specified default to 1
if '=' not in key:
key += '=1'
newargs[i] = newargs[i + 1] = ''
if key == 'WASM_BACKEND=1':
exit_with_error('do not set -s WASM_BACKEND, instead set EMCC_WASM_BACKEND=1 in the environment')
newargs = [arg for arg in newargs if arg is not '']
settings_key_changes = set()
for s in settings_changes:
key, value = s.split('=', 1)
# Find input files
# These three arrays are used to store arguments of different types for
# type-specific processing. In order to shuffle the arguments back together
# after processing, all of these arrays hold tuples (original_index, value).
# Note that the index part of the tuple can have a fractional part for input
# arguments that expand into multiple processed arguments, as in -Wl,-f1,-f2.
input_files = []
libs = []
link_flags = []
# All of the above arg lists entries contain indexes into the full argument
# list. In order to add extra implicit args (, etc) below, we keep a
# counter for the next index that should be used.
next_arg_index = len(newargs)
has_source_inputs = False
has_header_inputs = False
lib_dirs = [shared.path_from_root('system', 'local', 'lib'),
shared.path_from_root('system', 'lib')]
# find input files this a simple heuristic. we should really analyze
# based on a full understanding of gcc params, right now we just assume that
# what is left contains no more |-x OPT| things
for i in range(len(newargs)):
arg = newargs[i]
if i > 0:
prev = newargs[i - 1]
if prev in ('-MT', '-MF', '-MQ', '-D', '-U', '-o', '-x',
'-Xpreprocessor', '-include', '-imacros', '-idirafter',
'-iprefix', '-iwithprefix', '-iwithprefixbefore',
'-isysroot', '-imultilib', '-A', '-isystem', '-iquote',
'-install_name', '-compatibility_version',
'-current_version', '-I', '-L', '-include-pch'):
continue # ignore this gcc-style argument
if os.path.islink(arg) and get_file_suffix(os.path.realpath(arg)) in SOURCE_ENDINGS + BITCODE_ENDINGS + DYNAMICLIB_ENDINGS + ASSEMBLY_ENDINGS + HEADER_ENDINGS:
arg = os.path.realpath(arg)
if not arg.startswith('-'):
if not os.path.exists(arg):
exit_with_error('%s: No such file or directory ("%s" was expected to be an input file, based on the commandline arguments provided)', arg, arg)
file_suffix = get_file_suffix(arg)
if file_suffix in SOURCE_ENDINGS + BITCODE_ENDINGS + DYNAMICLIB_ENDINGS + ASSEMBLY_ENDINGS + HEADER_ENDINGS or shared.Building.is_ar(arg): # we already removed -o <target>, so all these should be inputs
newargs[i] = ''
if file_suffix.endswith(SOURCE_ENDINGS):
input_files.append((i, arg))
has_source_inputs = True
elif file_suffix.endswith(HEADER_ENDINGS):
input_files.append((i, arg))
has_header_inputs = True
elif file_suffix.endswith(ASSEMBLY_ENDINGS) or shared.Building.is_bitcode(arg) or shared.Building.is_ar(arg):
input_files.append((i, arg))
elif 'WASM_OBJECT_FILES=0' not in settings_changes and shared.Building.is_wasm(arg):
# this is before libraries, since wasm static libraries ( that contains wasm) are just
# object files to be linked
input_files.append((i, arg))
elif file_suffix.endswith(STATICLIB_ENDINGS + DYNAMICLIB_ENDINGS):
# if it's not, and it's a library, just add it to libs to find later
l = unsuffixed_basename(arg)
for prefix in LIB_PREFIXES:
if not prefix:
if l.startswith(prefix):
l = l[len(prefix):]
libs.append((i, l))
newargs[i] = ''
logger.warning(arg + ' is not a valid input file')
elif file_suffix.endswith(STATICLIB_ENDINGS):
if not shared.Building.is_ar(arg):
if shared.Building.is_bitcode(arg):
message = arg + ': File has a suffix of a static library ' + str(STATICLIB_ENDINGS) + ', but instead is an LLVM bitcode file! When linking LLVM bitcode files, use one of the suffixes ' + str(BITCODE_ENDINGS)
message = arg + ': Unknown format, not a static library!'
if has_fixed_language_mode:
newargs[i] = ''
input_files.append((i, arg))
has_source_inputs = True
exit_with_error(arg + ": Input file has an unknown suffix, don't know what to do with it!")
elif arg.startswith('-L'):
newargs[i] = ''
elif arg.startswith('-l'):
libs.append((i, arg[2:]))
newargs[i] = ''
elif arg.startswith('-Wl,'):
# Multiple comma separated link flags can be specified. Create fake
# fractional indices for these: -Wl,a,b,c,d at index 4 becomes:
# (4, a), (4.25, b), (4.5, c), (4.75, d)
link_flags_to_add = arg.split(',')[1:]
for flag_index, flag in enumerate(link_flags_to_add):
link_flags.append((i + float(flag_index) / len(link_flags_to_add), flag))
newargs[i] = ''
elif arg == '-s':
# -s and some other compiler flags are normally passed onto the linker
# TODO(sbc): Pass this and other flags through when using lld
# link_flags.append((i, arg))
newargs[i] = ''
original_input_files = input_files[:]
newargs = [a for a in newargs if a is not '']
# -c means do not link in gcc, and for us, the parallel is to not go all the way to JS, but stop at bitcode
has_dash_c = '-c' in newargs
if has_dash_c:
assert has_source_inputs or has_header_inputs, 'Must have source code or header inputs to use -c'
target = target_basename + '.o'
final_suffix = '.o'
if '-E' in newargs:
final_suffix = '.eout' # not bitcode, not js; but just result from preprocessing stage of the input file
if '-M' in newargs or '-MM' in newargs:
final_suffix = '.mout' # not bitcode, not js; but just dependency rule of the input file
# target is now finalized, can finalize other _target s
if final_suffix == '.mjs':
shared.Settings.EXPORT_ES6 = 1
shared.Settings.MODULARIZE = 1
js_target = target
js_target = unsuffixed(target) + '.js'
asm_target = unsuffixed(js_target) + '.asm.js' # might not be used, but if it is, this is the name
wasm_text_target = asm_target.replace('.asm.js', '.wast') # ditto, might not be used
wasm_binary_target = asm_target.replace('.asm.js', '.wasm') # ditto, might not be used
if final_suffix == '.html' and not options.separate_asm and 'PRECISE_F32=2' in settings_changes:
options.separate_asm = True
logger.warning('forcing separate asm output (--separate-asm), because -s PRECISE_F32=2 was passed.')
if options.separate_asm:
shared.Settings.SEPARATE_ASM = shared.JS.get_subresource_location(asm_target)
# Libraries are searched before settings_changes are applied, so apply the
# value for STRICT and ERROR_ON_MISSING_LIBRARIES from command line already
# now.
def get_last_setting_change(setting):
return ([None] + [x for x in settings_changes if x.startswith(setting + '=')])[-1]
strict_cmdline = get_last_setting_change('STRICT')
if strict_cmdline:
shared.Settings.STRICT = int(strict_cmdline.split('=', 1)[1])
if shared.Settings.STRICT:
error_on_missing_libraries_cmdline = get_last_setting_change('ERROR_ON_MISSING_LIBRARIES')
if error_on_missing_libraries_cmdline:
shared.Settings.ERROR_ON_MISSING_LIBRARIES = int(error_on_missing_libraries_cmdline[len('ERROR_ON_MISSING_LIBRARIES='):])
settings_changes.append(process_libraries(libs, lib_dirs, settings_changes, input_files))
# If not compiling to JS, then we are compiling to an intermediate bitcode objects or library, so
# ignore dynamic linking, since multiple dynamic linkings can interfere with each other
if get_file_suffix(target) not in JS_CONTAINING_ENDINGS or options.ignore_dynamic_linking:
def check(input_file):
if get_file_suffix(input_file) in DYNAMICLIB_ENDINGS:
if not options.ignore_dynamic_linking:
logger.warning('ignoring dynamic library %s because not compiling to JS or HTML, remember to link it when compiling to JS or HTML at the end', os.path.basename(input_file))
return False
return True
input_files = [f for f in input_files if check(f[1])]
if len(input_files) == 0:
exit_with_error('no input files\nnote that input files without a known suffix are ignored, make sure your input files end with one of: ' + str(SOURCE_ENDINGS + BITCODE_ENDINGS + DYNAMICLIB_ENDINGS + STATICLIB_ENDINGS + ASSEMBLY_ENDINGS + HEADER_ENDINGS))
newargs = shared.COMPILER_OPTS + newargs
if options.separate_asm and final_suffix != '.html':
# Apply optimization level settings
shared.Settings.apply_opt_level(opt_level=options.opt_level, shrink_level=options.shrink_level, noisy=True)
# For users that opt out of WARN_ON_UNDEFINED_SYMBOLS we assume they also
# want to opt out of ERROR_ON_UNDEFINED_SYMBOLS.
if 'WARN_ON_UNDEFINED_SYMBOLS=0' in settings_changes:
# Set ASM_JS default here so that we can override it from the command line.
shared.Settings.ASM_JS = 1 if options.opt_level > 0 else 2
# Apply -s settings in newargs here (after optimization levels, so they can override them)
# Reconfigure the cache now that settings have been applied (e.g. WASM_OBJECT_FILES)
# TODO: remove
# Note the exports the user requested
shared.Building.user_requested_exports = shared.Settings.EXPORTED_FUNCTIONS[:]
if options.bind:
# If we are using embind and generating JS, now is the time to link in bind.cpp
if final_suffix in JS_CONTAINING_ENDINGS:
input_files.append((next_arg_index, shared.path_from_root('system', 'lib', 'embind', 'bind.cpp')))
next_arg_index += 1
# -s ASSERTIONS=1 implies the heaviest stack overflow check mode. Set the implication here explicitly to avoid having to
# do preprocessor "#if defined(ASSERTIONS) || defined(STACK_OVERFLOW_CHECK)" in .js files, which is not supported.
if shared.Settings.ASSERTIONS:
shared.Settings.STACK_OVERFLOW_CHECK = 2
if shared.Settings.WASM_OBJECT_FILES and not shared.Settings.WASM_BACKEND:
if 'WASM_OBJECT_FILES=1' in settings_changes:
logger.error('WASM_OBJECT_FILES can only be used with wasm backend')
return 1
shared.Settings.WASM_OBJECT_FILES = 0
if not shared.Settings.STRICT:
# The preprocessor define EMSCRIPTEN is deprecated. Don't pass it to code
# in strict mode. Code should use the define __EMSCRIPTEN__ instead.
# Use settings
if options.debug_level > 1 and options.use_closure_compiler:
logger.warning('disabling closure because debug info was requested')
options.use_closure_compiler = False
assert not (shared.Settings.EMTERPRETIFY_FILE and shared.Settings.SINGLE_FILE), 'cannot have both EMTERPRETIFY_FILE and SINGLE_FILE enabled at the same time'
assert not (not shared.Settings.DYNAMIC_EXECUTION and options.use_closure_compiler), 'cannot have both NO_DYNAMIC_EXECUTION and closure compiler enabled at the same time'
if options.emrun:
assert not shared.Settings.MINIMAL_RUNTIME, '--emrun is not compatible with -s MINIMAL_RUNTIME=1'
if options.use_closure_compiler:
shared.Settings.USE_CLOSURE_COMPILER = options.use_closure_compiler
if not shared.check_closure_compiler():
exit_with_error('fatal: closure compiler is not configured correctly')
if options.use_closure_compiler == 2 and shared.Settings.ASM_JS == 1:
shared.WarningManager.warn('ALMOST_ASM', 'not all asm.js optimizations are possible with --closure 2, disabling those - your code will be run more slowly')
shared.Settings.ASM_JS = 2
if shared.Settings.MAIN_MODULE:
assert not shared.Settings.SIDE_MODULE
if shared.Settings.MAIN_MODULE != 2:
shared.Settings.INCLUDE_FULL_LIBRARY = 1
elif shared.Settings.SIDE_MODULE:
assert not shared.Settings.MAIN_MODULE
options.memory_init_file = False # memory init file is not supported with asm.js side modules, must be executable synchronously (for dlopen)
if shared.Settings.MAIN_MODULE or shared.Settings.SIDE_MODULE:
assert shared.Settings.ASM_JS, 'module linking requires asm.js output (-s ASM_JS=1)'
if shared.Settings.MAIN_MODULE != 2 and shared.Settings.SIDE_MODULE != 2:
shared.Settings.LINKABLE = 1
shared.Settings.RELOCATABLE = 1
assert not options.use_closure_compiler, 'cannot use closure compiler on shared modules'
# shared modules need memory utilities to allocate their memory
shared.Settings.ALLOW_TABLE_GROWTH = 1
if shared.Settings.USE_PTHREADS:
# These runtime methods are called from worker.js
shared.Settings.EXPORTED_RUNTIME_METHODS += ['establishStackSpace', 'dynCall_ii']
if shared.Settings.MODULARIZE_INSTANCE:
shared.Settings.MODULARIZE = 1
if shared.Settings.MODULARIZE:
assert not options.proxy_to_worker, '-s MODULARIZE=1 and -s MODULARIZE_INSTANCE=1 are not compatible with --proxy-to-worker (if you want to run in a worker with -s MODULARIZE=1, you likely want to do the worker side setup manually)'
if shared.Settings.LEGACY_VM_SUPPORT:
# legacy vms don't have wasm
assert not shared.Settings.WASM, 'LEGACY_VM_SUPPORT is only supported for asm.js, and not wasm. Build with -s WASM=0'
# Silently drop any individual backwards compatibility emulation flags that are known never to occur on browsers that support WebAssembly.
if shared.Settings.WASM:
if shared.Settings.STB_IMAGE and final_suffix in JS_CONTAINING_ENDINGS:
input_files.append((next_arg_index, shared.path_from_root('third_party', 'stb_image.c')))
next_arg_index += 1
shared.Settings.EXPORTED_FUNCTIONS += ['_stbi_load', '_stbi_load_from_memory', '_stbi_image_free']
# stb_image 2.x need to have STB_IMAGE_IMPLEMENTATION defined to include the implementation when compiling
if shared.Settings.ASMFS and final_suffix in JS_CONTAINING_ENDINGS:
input_files.append((next_arg_index, shared.path_from_root('system', 'lib', 'fetch', 'asmfs.cpp')))
next_arg_index += 1
shared.Settings.FILESYSTEM = 0
shared.Settings.FETCH = 1
options.js_libraries.append(shared.path_from_root('src', 'library_asmfs.js'))
if shared.Settings.FETCH and final_suffix in JS_CONTAINING_ENDINGS:
input_files.append((next_arg_index, shared.path_from_root('system', 'lib', 'fetch', 'emscripten_fetch.cpp')))
next_arg_index += 1
options.js_libraries.append(shared.path_from_root('src', 'library_fetch.js'))
if shared.Settings.USE_PTHREADS:
shared.Settings.FETCH_WORKER_FILE = unsuffixed(os.path.basename(target)) + '.fetch.js'
forced_stdlibs = []
if shared.Settings.DEMANGLE_SUPPORT:
shared.Settings.EXPORTED_FUNCTIONS += ['___cxa_demangle']
forced_stdlibs += ['libc++abi']
if not shared.Settings.ONLY_MY_CODE and not shared.Settings.MINIMAL_RUNTIME:
# Always need malloc and free to be kept alive and exported, for internal use and other modules
shared.Settings.EXPORTED_FUNCTIONS += ['_malloc', '_free']
if shared.Settings.WASM_BACKEND:
# setjmp/longjmp and exception handling JS code depends on this so we
# include it by default. Should be elimiated by meta-DCE if unused.
shared.Settings.EXPORTED_FUNCTIONS += ['_setThrew']
if shared.Settings.RELOCATABLE and not shared.Settings.DYNAMIC_EXECUTION:
exit_with_error('cannot have both DYNAMIC_EXECUTION=0 and RELOCATABLE enabled at the same time, since RELOCATABLE needs to eval()')
if shared.Settings.RELOCATABLE:
assert shared.Settings.GLOBAL_BASE < 1
if 'EMULATED_FUNCTION_POINTERS' not in settings_key_changes:
shared.Settings.EMULATED_FUNCTION_POINTERS = 2 # by default, use optimized function pointer emulation
if shared.Settings.EMTERPRETIFY:
shared.Settings.FINALIZE_ASM_JS = 0
# shared.Settings.GLOBAL_BASE = 8*256 # keep enough space at the bottom for a full stack frame, for z-interpreter
shared.Settings.SIMPLIFY_IFS = 0 # this is just harmful for emterpreting
shared.Settings.EXPORTED_FUNCTIONS += ['emterpret']
if not options.js_opts:
logger.debug('enabling js opts for EMTERPRETIFY')
options.js_opts = True
options.force_js_opts = True
if options.use_closure_compiler == 2:
exit_with_error('EMTERPRETIFY requires valid asm.js, and is incompatible with closure 2 which disables that')
assert not use_source_map(options), 'EMTERPRETIFY is not compatible with source maps (maps are not useful in emterpreted code, and splitting out non-emterpreted source maps is not yet implemented)'
if shared.Settings.DEAD_FUNCTIONS:
if not options.js_opts:
logger.debug('enabling js opts for DEAD_FUNCTIONS')
options.js_opts = True
options.force_js_opts = True
if options.proxy_to_worker:
shared.Settings.PROXY_TO_WORKER = 1
if options.use_preload_plugins or len(options.preload_files) or len(options.embed_files):
if shared.Settings.NODERAWFS:
exit_with_error('--preload-file and --embed-file cannot be used with NODERAWFS which disables virtual filesystem')
# if we include any files, or intend to use preload plugins, then we definitely need filesystem support
shared.Settings.FORCE_FILESYSTEM = 1
if options.proxy_to_worker or options.use_preload_plugins:
shared.Settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$Browser']
if shared.Settings.FILESYSTEM and not shared.Settings.ONLY_MY_CODE:
if shared.Settings.SUPPORT_ERRNO:
shared.Settings.EXPORTED_FUNCTIONS += ['___errno_location'] # so FS can report errno back to C
# to flush streams on FS exit, we need to be able to call fflush
# we only include it if the runtime is exitable, or when ASSERTIONS
# (ASSERTIONS will check that streams do not need to be flushed,
# helping people see when they should have disabled NO_EXIT_RUNTIME)
if shared.Settings.EXIT_RUNTIME or shared.Settings.ASSERTIONS:
shared.Settings.EXPORTED_FUNCTIONS += ['_fflush']
if shared.Settings.USE_PTHREADS:
if shared.Settings.USE_PTHREADS == 2:
exit_with_error('USE_PTHREADS=2 is not longer supported')
if shared.Settings.ALLOW_MEMORY_GROWTH:
exit_with_error('Memory growth is not yet supported with pthreads')
# UTF8Decoder.decode doesn't work with a view of a SharedArrayBuffer
shared.Settings.TEXTDECODER = 0
options.js_libraries.append(shared.path_from_root('src', 'library_pthread.js'))
# set location of worker.js
shared.Settings.PTHREAD_WORKER_FILE = unsuffixed(os.path.basename(target)) + '.worker.js'
options.js_libraries.append(shared.path_from_root('src', 'library_pthread_stub.js'))
if shared.Settings.FORCE_FILESYSTEM and not shared.Settings.MINIMAL_RUNTIME:
# when the filesystem is forced, we export by default methods that filesystem usage
# may need, including filesystem usage from standalone file packager output (i.e.
# file packages not built together with emcc, but that are loaded at runtime
# separately, and they need emcc's output to contain the support they need)
if not shared.Settings.ASMFS:
if shared.Settings.USE_PTHREADS:
if shared.Settings.MODULARIZE:
# MODULARIZE+USE_PTHREADS mode requires extra exports out to Module so that worker.js
# can access them:
# general threading variables:
shared.Settings.EXPORTED_RUNTIME_METHODS += ['PThread', 'ExitStatus']
# pthread stack setup:
shared.Settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$establishStackSpaceInJsModule']
shared.Settings.EXPORTED_FUNCTIONS += ['establishStackSpaceInJsModule']
# stack check:
if shared.Settings.STACK_OVERFLOW_CHECK:
shared.Settings.EXPORTED_RUNTIME_METHODS += ['writeStackCookie', 'checkStackCookie']
if shared.Settings.LINKABLE:
exit_with_error('-s LINKABLE=1 is not supported with -s USE_PTHREADS>0!')
if shared.Settings.SIDE_MODULE:
exit_with_error('-s SIDE_MODULE=1 is not supported with -s USE_PTHREADS>0!')
if shared.Settings.MAIN_MODULE:
exit_with_error('-s MAIN_MODULE=1 is not supported with -s USE_PTHREADS>0!')
if shared.Settings.EMTERPRETIFY:
exit_with_error('-s EMTERPRETIFY=1 is not supported with -s USE_PTHREADS>0!')
if shared.Settings.PROXY_TO_WORKER:
exit_with_error('--proxy-to-worker is not supported with -s USE_PTHREADS>0! Use the option -s PROXY_TO_PTHREAD=1 if you want to run the main thread of a multithreaded application in a web worker.')
if shared.Settings.PROXY_TO_PTHREAD:
exit_with_error('-s PROXY_TO_PTHREAD=1 requires -s USE_PTHREADS to work!')
if shared.Settings.OUTLINING_LIMIT:
if shared.Settings.WASM_BACKEND:
exit_with_error('OUTLINING_LIMIT is not compatible with the LLVM wasm backend')
if not options.js_opts:
logger.debug('enabling js opts as optional functionality implemented as a js opt was requested')
options.js_opts = True
options.force_js_opts = True
# Enable minification of asm.js imports on -O1 and higher if -g1 or lower is used.
if options.opt_level >= 1 and options.debug_level < 2 and not shared.Settings.WASM:
if shared.Settings.WASM:
if not shared.Building.need_asm_js_file():
asm_target = asm_target.replace('.asm.js', '.temp.asm.js')
if shared.Settings.WASM:
if shared.Settings.TOTAL_MEMORY % 65536 != 0:
exit_with_error('For wasm, TOTAL_MEMORY must be a multiple of 64KB, was ' + str(shared.Settings.TOTAL_MEMORY))
if shared.Settings.TOTAL_MEMORY < 16 * 1024 * 1024:
exit_with_error('TOTAL_MEMORY must be at least 16MB, was ' + str(shared.Settings.TOTAL_MEMORY))
if shared.Settings.TOTAL_MEMORY % (16 * 1024 * 1024) != 0:
exit_with_error('For asm.js, TOTAL_MEMORY must be a multiple of 16MB, was ' + str(shared.Settings.TOTAL_MEMORY))
if shared.Settings.TOTAL_MEMORY < shared.Settings.TOTAL_STACK:
exit_with_error('TOTAL_MEMORY must be larger than TOTAL_STACK, was ' + str(shared.Settings.TOTAL_MEMORY) + ' (TOTAL_STACK=' + str(shared.Settings.TOTAL_STACK) + ')')
if shared.Settings.WASM_MEM_MAX != -1 and shared.Settings.WASM_MEM_MAX % 65536 != 0:
exit_with_error('WASM_MEM_MAX must be a multiple of 64KB, was ' + str(shared.Settings.WASM_MEM_MAX))
if shared.Settings.USE_PTHREADS and shared.Settings.WASM and shared.Settings.ALLOW_MEMORY_GROWTH and shared.Settings.WASM_MEM_MAX == -1:
exit_with_error('If pthreads and memory growth are enabled, WASM_MEM_MAX must be set')
if shared.Settings.EXPORT_ES6 and not shared.Settings.MODULARIZE:
exit_with_error('EXPORT_ES6 requires MODULARIZE to be set')
# When MODULARIZE option is used, currently declare all module exports
# individually - TODO: this could be optimized
if shared.Settings.MODULARIZE and not shared.Settings.DECLARE_ASM_MODULE_EXPORTS:
logger.warning('Enabling -s DECLARE_ASM_MODULE_EXPORTS=1, since MODULARIZE currently requires declaring asm.js/wasm module exports in full')
# In MINIMAL_RUNTIME when modularizing, by default output asm.js module under the same name as the JS module. This allows code to share same loading function for both JS and asm.js modules,
# to save code size. The intent is that loader code captures the function variable from global scope to XHR loader local scope when it finishes loading, to avoid polluting global JS scope with
# variables. This provides safety via encapsulation. See src/shell_minimal_runtime.html for an example.
if shared.Settings.MINIMAL_RUNTIME and not shared.Settings.SEPARATE_ASM_MODULE_NAME and not shared.Settings.WASM and shared.Settings.MODULARIZE:
shared.Settings.SEPARATE_ASM_MODULE_NAME = 'var ' + shared.Settings.EXPORT_NAME
if shared.Settings.MODULARIZE and shared.Settings.SEPARATE_ASM and not shared.Settings.WASM and not shared.Settings.SEPARATE_ASM_MODULE_NAME:
exit_with_error('Targeting asm.js with --separate-asm and -s MODULARIZE=1 requires specifying the target variable name to which the asm.js module is loaded into. See for details')
# Apply default option if no custom name is provided
if not shared.Settings.SEPARATE_ASM_MODULE_NAME:
shared.Settings.SEPARATE_ASM_MODULE_NAME = 'Module["asm"]'
elif shared.Settings.WASM:
exit_with_error('-s SEPARATE_ASM_MODULE_NAME option only applies to when targeting asm.js, not with WebAssembly!')
if shared.Settings.MINIMAL_RUNTIME:
# Minimal runtime uses a different default shell file
if options.shell_path == shared.path_from_root('src', 'shell.html'):
options.shell_path = shared.path_from_root('src', 'shell_minimal_runtime.html')
# Remove the default exported functions 'memcpy', 'memset', 'malloc', 'free', etc. - those should only be linked in if used
# Always build with STRICT mode enabled
shared.Settings.STRICT = 1
# Always use the new HTML5 API event target lookup rules (TODO: enable this when the other PR lands)
# In asm.js always use memory init file to get the best code size, other modes are not currently supported.
if not shared.Settings.WASM:
options.memory_init_file = True
if shared.Settings.MODULARIZE and not shared.Settings.MODULARIZE_INSTANCE and shared.Settings.EXPORT_NAME == 'Module' and final_suffix == '.html' and \
(options.shell_path == shared.path_from_root('src', 'shell.html') or options.shell_path == shared.path_from_root('src', 'shell_minimal.html')):
exit_with_error('Due to collision in variable name "Module", the shell file "' + options.shell_path + '" is not compatible with build options "-s MODULARIZE=1 -s EXPORT_NAME=Module". Either provide your own shell file, change the name of the export to something else to avoid the name collision. (see for details)')
if shared.Settings.WASM:
if shared.Settings.SINGLE_FILE:
# placeholder strings for JS glue, to be replaced with subresource locations in do_binaryen
shared.Settings.WASM_TEXT_FILE = shared.FilenameReplacementStrings.WASM_TEXT_FILE
shared.Settings.WASM_BINARY_FILE = shared.FilenameReplacementStrings.WASM_BINARY_FILE
shared.Settings.ASMJS_CODE_FILE = shared.FilenameReplacementStrings.ASMJS_CODE_FILE
# set file locations, so that JS glue can find what it needs
shared.Settings.WASM_TEXT_FILE = shared.JS.escape_for_js_string(os.path.basename(wasm_text_target))
shared.Settings.WASM_BINARY_FILE = shared.JS.escape_for_js_string(os.path.basename(wasm_binary_target))
shared.Settings.ASMJS_CODE_FILE = shared.JS.escape_for_js_string(os.path.basename(asm_target))
shared.Settings.ASM_JS = 2 # when targeting wasm, we use a wasm Memory, but that is not compatible with asm.js opts
# a higher global base is useful for optimizing load/store offsets, as it enables the --post-emscripten pass
shared.Settings.GLOBAL_BASE = 1024
logger.warning('for wasm there is no need to set ELIMINATE_DUPLICATE_FUNCTIONS, the binaryen optimizer does it automatically')
if shared.Settings.OUTLINING_LIMIT:
logger.warning('for wasm there is usually no need to set OUTLINING_LIMIT, as VMs can handle large functions well anyhow')
# default precise-f32 to on, since it works well in wasm
shared.Settings.PRECISE_F32 = 1
if options.js_opts and not options.force_js_opts:
options.js_opts = None
logger.debug('asm.js opts not forced by user or an option that depends them, and we do not intend to run the asm.js, so disabling and leaving opts to the binaryen optimizer')
if options.use_closure_compiler == 2:
exit_with_error('closure compiler mode 2 assumes the code is asm.js, so not meaningful for wasm')
# for simplicity, we always have a mem init file, which may also be imported into the wasm module.
# * if we also supported js mem inits we'd have 4 modes
# * and js mem inits are useful for avoiding a side file, but the wasm module avoids that anyhow
if any(s.startswith('MEM_INIT_METHOD=') for s in settings_changes):
exit_with_error('MEM_INIT_METHOD is not supported in wasm. Memory will be embedded in the wasm binary if threads are not used, and included in a separate file if threads are used.')
options.memory_init_file = True
if not shared.Settings.MINIMAL_RUNTIME: # BINARYEN_ASYNC_COMPILATION and SWAPPABLE_ASM_MODULE do not have a meaning in MINIMAL_RUNTIME (always async)
if shared.Settings.BINARYEN_ASYNC_COMPILATION == 1:
# async compilation requires a swappable module - we swap it in when it's ready
shared.Settings.SWAPPABLE_ASM_MODULE = 1
# if not wasm-only, we can't do async compilation as the build can run in other
# modes than wasm (like asm.js) which may not support an async step
warning = 'This will reduce performance and compatibility (some browsers limit synchronous compilation), see'
if 'BINARYEN_ASYNC_COMPILATION=1' in settings_changes:
logger.warning('BINARYEN_ASYNC_COMPILATION requested, but disabled because of user options. ' + warning)
elif 'BINARYEN_ASYNC_COMPILATION=0' not in settings_changes:
logger.warning('BINARYEN_ASYNC_COMPILATION disabled due to user options. ' + warning)
if not shared.Settings.DECLARE_ASM_MODULE_EXPORTS:
# Swappable wasm module/asynchronous wasm compilation requires an indirect stub
# function generated to each function export from wasm module, so cannot use the
# concise form of grabbing exports that does not need to refer to each export individually.
if shared.Settings.SWAPPABLE_ASM_MODULE == 1:
logger.warning('Enabling -s DECLARE_ASM_MODULE_EXPORTS=1 since -s SWAPPABLE_ASM_MODULE=1 is used')
# we will include the mem init data in the wasm, when we don't need the
# mem init file to be loadable by itself
shared.Settings.MEM_INIT_IN_WASM = not shared.Settings.USE_PTHREADS
# wasm side modules have suffix .wasm
if shared.Settings.SIDE_MODULE and target.endswith('.js'):
logger.warning('output suffix .js requested, but wasm side modules are just wasm files; emitting only a .wasm, no .js')
if options.separate_asm:
exit_with_error('cannot --separate-asm when emitting wasm, since not emitting asm.js')
if shared.Settings.WASM_BACKEND:
options.js_opts = None
# wasm backend output can benefit from the binaryen optimizer (in asm2wasm,
# we run the optimizer during asm2wasm itself). use it, if not overridden
if 'BINARYEN_PASSES' not in settings_key_changes:
passes = []
if not shared.Settings.EXIT_RUNTIME:
passes += ['--no-exit-runtime']
if options.opt_level > 0 or options.shrink_level > 0:
passes += [shared.Building.opt_level_to_str(options.opt_level, options.shrink_level)]
passes += ['--post-emscripten']
if shared.Settings.GLOBAL_BASE >= 1024: # hardcoded value in the binaryen pass
passes += ['--low-memory-unused']
if options.debug_level < 3:
passes += ['--strip-debug']
if not shared.Settings.EMIT_PRODUCERS_SECTION:
passes += ['--strip-producers']
if passes:
shared.Settings.BINARYEN_PASSES = ','.join(passes)
# to bootstrap struct_info, we need binaryen
os.environ['EMCC_WASM_BACKEND_BINARYEN'] = '1'
# run safe-heap as a binaryen pass
if shared.Settings.SAFE_HEAP and shared.Building.is_wasm_only():
if shared.Settings.BINARYEN_PASSES:
shared.Settings.BINARYEN_PASSES += ','
shared.Settings.BINARYEN_PASSES += 'safe-heap'
# emulated function pointer casts is emulated in wasm using a binaryen pass
if shared.Settings.BINARYEN_PASSES:
shared.Settings.BINARYEN_PASSES += ','
shared.Settings.BINARYEN_PASSES += 'fpcast-emu'
# we also need emulated function pointers for that, as we need a single flat
# table, as is standard in wasm, and not asm.js split ones.
# wasm outputs are only possible with a side wasm
if target.endswith(WASM_ENDINGS):
shared.Settings.EMITTING_JS = 0
js_target = misc_temp_files.get(suffix='.js').name
if shared.Settings.EVAL_CTORS:
if not shared.Settings.WASM:
# for asm.js: this option is not a js optimizer pass, but does run the js optimizer internally, so
# we need to generate proper code for that (for wasm, we run a binaryen tool for this)
shared.Settings.RUNNING_JS_OPTS = 1
# memory growth does not work in dynamic linking, except for wasm
if not shared.Settings.WASM and (shared.Settings.MAIN_MODULE or shared.Settings.SIDE_MODULE):
assert not shared.Settings.ALLOW_MEMORY_GROWTH, 'memory growth is not supported with shared asm.js modules'
if shared.Settings.MINIMAL_RUNTIME:
if shared.Settings.ALLOW_MEMORY_GROWTH:
logging.warning('-s ALLOW_MEMORY_GROWTH=1 is not yet supported with -s MINIMAL_RUNTIME=1')
if shared.Settings.EMTERPRETIFY:
exit_with_error('-s EMTERPRETIFY=1 is not supported with -s MINIMAL_RUNTIME=1')
if shared.Settings.USE_PTHREADS:
exit_with_error('-s USE_PTHREADS=1 is not yet supported with -s MINIMAL_RUNTIME=1')
if shared.Settings.PRECISE_F32 == 2:
exit_with_error('-s PRECISE_F32=2 is not supported with -s MINIMAL_RUNTIME=1')
if shared.Settings.SINGLE_FILE:
exit_with_error('-s SINGLE_FILE=1 is not supported with -s MINIMAL_RUNTIME=1')
if shared.Settings.ALLOW_MEMORY_GROWTH and shared.Settings.ASM_JS == 1:
# this is an issue in asm.js, but not wasm
if not shared.Settings.WASM:
shared.Settings.ASM_JS = 2 # memory growth does not validate as asm.js
# safe heap in asm.js uses the js optimizer (in wasm-only mode we can use binaryen)
if shared.Settings.SAFE_HEAP and not shared.Building.is_wasm_only():
if not options.js_opts:
logger.debug('enabling js opts for SAFE_HEAP')
options.js_opts = True
options.force_js_opts = True
if options.js_opts:
shared.Settings.RUNNING_JS_OPTS = 1
if shared.Settings.CYBERDWARF:
options.debug_level = max(options.debug_level, 2)
shared.Settings.BUNDLED_CD_DEBUG_FILE = target + ".cd"
options.js_libraries.append(shared.path_from_root('src', 'library_cyberdwarf.js'))
options.js_libraries.append(shared.path_from_root('src', 'library_debugger_toolkit.js'))
if options.tracing:
if shared.Settings.ALLOW_MEMORY_GROWTH:
shared.Settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['emscripten_trace_report_memory_layout']
if shared.Settings.ONLY_MY_CODE:
options.separate_asm = True
shared.Settings.FINALIZE_ASM_JS = False
# MINIMAL_RUNTIME always use separate .asm.js file for best performance and memory usage
if shared.Settings.MINIMAL_RUNTIME and not shared.Settings.WASM:
options.separate_asm = True
if shared.Settings.GLOBAL_BASE < 0:
shared.Settings.GLOBAL_BASE = 8 # default if nothing else sets it
if shared.Settings.WASM_BACKEND:
if shared.Settings.SIMD:
# We leave the -O option in place so that the clang front-end runs in that
# optimization mode, but we disable the actual optimization passes, as we'll
# run them separately.
if options.opt_level > 0:
if not shared.Settings.LEGALIZE_JS_FFI:
assert shared.Building.is_wasm_only(), 'LEGALIZE_JS_FFI incompatible with RUNNING_JS_OPTS.'
shared.Settings.OPT_LEVEL = options.opt_level
shared.Settings.DEBUG_LEVEL = options.debug_level
shared.Settings.PROFILING_FUNCS = options.profiling_funcs
shared.Settings.SOURCE_MAP_BASE = options.source_map_base or ''
## Compile source code to bitcode
logger.debug('compiling to bitcode')
temp_files = []
# exit block 'parse arguments and setup'
log_time('parse arguments and setup')
# we are about to start using temp dirs. serialize access to the temp dir
# when using EMCC_DEBUG, since we don't want multiple processes would to
# use it at once, they might collide if they happen to use the same
# tempfile names
with ToolchainProfiler.profile_block('bitcodeize inputs'):
# Precompiled headers support
if has_header_inputs:
headers = [header for _, header in input_files]
for header in headers:
assert header.endswith(HEADER_ENDINGS), 'if you have one header input, we assume you want to precompile headers, and cannot have source files or other inputs as well: ' + str(headers) + ' : ' + header
args = newargs + headers
if specified_target:
args += ['-o', specified_target]
args = system_libs.process_args(args, shared.Settings)
logger.debug("running (for precompiled headers): " + clang_compiler + ' ' + ' '.join(args))
return run_process([clang_compiler] + args, check=False).returncode
def get_bitcode_file(input_file):
if final_suffix not in JS_CONTAINING_ENDINGS:
# no need for a temp file, just emit to the right place
if len(input_files) == 1:
# can just emit directly to the target
if specified_target:
if specified_target.endswith('/') or specified_target.endswith('\\') or os.path.isdir(specified_target):
return os.path.join(specified_target, os.path.basename(unsuffixed(input_file))) + options.default_object_extension
return specified_target
return unsuffixed(input_file) + final_suffix
if has_dash_c:
return unsuffixed(input_file) + options.default_object_extension
return in_temp(unsuffixed(uniquename(input_file)) + options.default_object_extension)
# Request LLVM debug info if explicitly specified, or building bitcode with -g, or if building a source all the way to JS with -g
if use_source_map(options) or ((final_suffix not in JS_CONTAINING_ENDINGS or (has_source_inputs and final_suffix in JS_CONTAINING_ENDINGS)) and options.requested_debug == '-g'):
# do not save llvm debug info if js optimizer will wipe it out anyhow (but if source maps are used, keep it)
if use_source_map(options) or not (final_suffix in JS_CONTAINING_ENDINGS and options.js_opts):
newargs.append('-g') # preserve LLVM debug info
options.debug_level = 4
shared.Settings.DEBUG_LEVEL = 4
# Bitcode args generation code
def get_clang_args(input_files):
args = [clang_compiler] + newargs + input_files
if not shared.Building.can_inline():
# For fastcomp backend, no LLVM IR functions should ever be annotated
# 'optnone', because that would skip running the SimplifyCFG pass on
# them, which is required to always run to clean up LandingPadInst
# instructions that are not needed.
if not shared.Settings.WASM_BACKEND:
args += ['-Xclang', '-disable-O0-optnone']
args = system_libs.process_args(args, shared.Settings)
return args
# -E preprocessor-only support
if '-E' in newargs or '-M' in newargs or '-MM' in newargs:
input_files = [x[1] for x in input_files]
cmd = get_clang_args(input_files)
if specified_target:
cmd += ['-o', specified_target]
# Do not compile, but just output the result from preprocessing stage or
# output the dependency rule. Warning: clang and gcc behave differently
# with -MF! (clang seems to not recognize it)
logger.debug(('just preprocessor ' if '-E' in newargs else 'just dependencies: ') + ' '.join(cmd))
return run_process(cmd, check=False).returncode
def compile_source_file(i, input_file):
logger.debug('compiling source file: ' + input_file)
output_file = get_bitcode_file(input_file)
temp_files.append((i, output_file))
args = get_clang_args([input_file]) + ['-c', '-o', output_file]
if shared.Settings.WASM_OBJECT_FILES:
for a in shared.Building.llvm_backend_args():
args += ['-mllvm', a]
logger.debug("running: " + ' '.join(shared.Building.doublequote_spaces(args))) # NOTE: Printing this line here in this specific format is important, it is parsed to implement the "emcc --cflags" command
if run_process(args, check=False).returncode != 0:
exit_with_error('compiler frontend failed to generate LLVM bitcode, halting')
# First, generate LLVM bitcode. For each input file, we get base.o with bitcode
for i, input_file in input_files:
file_ending = get_file_suffix(input_file)
if file_ending.endswith(SOURCE_ENDINGS):
compile_source_file(i, input_file)
else: # bitcode
if file_ending.endswith(BITCODE_ENDINGS):
logger.debug('using bitcode file: ' + input_file)
temp_files.append((i, input_file))
elif file_ending.endswith(DYNAMICLIB_ENDINGS) or shared.Building.is_ar(input_file):
logger.debug('using library file: ' + input_file)
temp_files.append((i, input_file))
elif file_ending.endswith(ASSEMBLY_ENDINGS):
logger.debug('assembling assembly file: ' + input_file)
temp_file = in_temp(unsuffixed(uniquename(input_file)) + '.o')
shared.Building.llvm_as(input_file, temp_file)
temp_files.append((i, temp_file))
if has_fixed_language_mode:
compile_source_file(i, input_file)
exit_with_error(input_file + ': Unknown file suffix when compiling to LLVM bitcode!')
# exit block 'bitcodeize inputs'
log_time('bitcodeize inputs')
with ToolchainProfiler.profile_block('process inputs'):
if not LEAVE_INPUTS_RAW and not shared.Settings.WASM_BACKEND:
assert len(temp_files) == len(input_files)
# Optimize source files
if optimizing(options.llvm_opts):
for pos, (_, input_file) in enumerate(input_files):
file_ending = get_file_suffix(input_file)
if file_ending.endswith(SOURCE_ENDINGS):
temp_file = temp_files[pos][1]
logger.debug('optimizing %s', input_file)
# if DEBUG:
# shutil.copyfile(temp_file, os.path.join(shared.configuration.CANONICAL_TEMP_DIR, 'to_opt.bc')) # useful when LLVM opt aborts
new_temp_file = in_temp(unsuffixed(uniquename(temp_file)) + '.o')
# after optimizing, lower intrinsics to libc calls so that our linking code
# will find them (otherwise, llvm.cos.f32() will not link in cosf(), and
# we end up calling out to JS for Math.cos).
opts = options.llvm_opts + ['-lower-non-em-intrinsics']
shared.Building.llvm_opt(temp_file, opts, new_temp_file)
temp_files[pos] = (temp_files[pos][0], new_temp_file)
# Decide what we will link
executable_endings = JS_CONTAINING_ENDINGS + ('.wasm',)
stop_at_bitcode = final_suffix not in executable_endings
if stop_at_bitcode or not shared.Settings.WASM_BACKEND:
# Filter link flags, keeping only those that knows
# how to deal with. We currently can't handle flags with options (like
# -Wl,-rpath,/bin:/lib, where /bin:/lib is an option for the -rpath
# flag).
link_flags = [f for f in link_flags if f[1] in SUPPORTED_LINKER_FLAGS]
linker_inputs = [val for _, val in sorted(temp_files + link_flags)]
# If we were just asked to generate bitcode, stop there
if stop_at_bitcode:
if not specified_target:
assert len(temp_files) == len(input_files)
for tempf, inputf in zip(temp_files, input_files):
safe_move(tempf[1], unsuffixed_basename(inputf[1]) + final_suffix)
if len(input_files) == 1:
input_file = input_files[0][1]
temp_file = temp_files[0][1]
bitcode_target = specified_target if specified_target else unsuffixed_basename(input_file) + final_suffix
if temp_file != input_file:
safe_move(temp_file, bitcode_target)
shutil.copyfile(temp_file, bitcode_target)
temp_output_base = unsuffixed(temp_file)
if os.path.exists(temp_output_base + '.d'):
# There was a .d file generated, from -MD or -MMD and friends, save a copy of it to where the output resides,
# adjusting the target name away from the temporary file name to the specified target.
# It will be deleted with the rest of the temporary directory.
deps = open(temp_output_base + '.d').read()
deps = deps.replace(temp_output_base + options.default_object_extension, specified_target)
with open(os.path.join(os.path.dirname(specified_target), os.path.basename(unsuffixed(input_file) + '.d')), "w") as out_dep:
assert len(original_input_files) == 1 or not has_dash_c, 'fatal error: cannot specify -o with -c with multiple files' + str(args) + ':' + str(original_input_files)
# We have a specified target (-o <target>), which is not JavaScript or HTML, and
# we have multiple files: Link them
logger.debug('link: ' + str(linker_inputs) + specified_target)
shared.Building.link_to_object(linker_inputs, specified_target)
logger.debug('stopping at bitcode')
if shared.Settings.SIDE_MODULE:
exit_with_error('SIDE_MODULE must only be used when compiling to an executable shared library, and not when emitting LLVM bitcode. That is, you should be emitting a .wasm file (for wasm) or a .js file (for asm.js). Note that when compiling to a typical native suffix for a shared library (.so, .dylib, .dll; which many build systems do) then Emscripten emits an LLVM bitcode file, which you should then compile to .wasm or .js with SIDE_MODULE.')
if final_suffix.lower() in ('.so', '.dylib', '.dll'):
logger.warning('When Emscripten compiles to a typical native suffix for shared libraries (.so, .dylib, .dll) then it emits an LLVM bitcode file. You should then compile that to an emscripten SIDE_MODULE (using that flag) with suffix .wasm (for wasm) or .js (for asm.js). (You may also want to adapt your build system to emit the more standard suffix for a file with LLVM bitcode, \'.bc\', which would avoid this warning.)')
return 0
# exit block 'process inputs'
log_time('process inputs')
## Continue on to create JavaScript
with ToolchainProfiler.profile_block('calculate system libraries'):
logger.debug('will generate JavaScript')
extra_files_to_link = []
# link in ports and system libraries, if necessary
if not LEAVE_INPUTS_RAW and \
not shared.Settings.BOOTSTRAPPING_STRUCT_INFO and \
not shared.Settings.ONLY_MY_CODE and \
not shared.Settings.SIDE_MODULE: # shared libraries/side modules link no C libraries, need them in parent
extra_files_to_link = system_libs.get_ports(shared.Settings)
extra_files_to_link += system_libs.calculate([f for _, f in sorted(temp_files)] + extra_files_to_link, in_temp, stdout_=None, stderr_=None, forced=forced_stdlibs)
# exit block 'calculate system libraries'
log_time('calculate system libraries')
def dedup_list(lst):
rtn = []
for item in lst:
if item not in rtn:
return rtn
# Make a final pass over shared.Settings.EXPORTED_FUNCTIONS to remove any
# duplication between functions added by the driver/libraries and function
# specified by the user
shared.Settings.EXPORTED_FUNCTIONS = dedup_list(shared.Settings.EXPORTED_FUNCTIONS)
with ToolchainProfiler.profile_block('link'):
# final will be an array if linking is deferred, otherwise a normal string.
if shared.Settings.WASM_BACKEND:
DEFAULT_FINAL = in_temp(target_basename + '.wasm')
DEFAULT_FINAL = in_temp(target_basename + '.bc')
def get_final():
global final
if isinstance(final, list):
return final
# First, combine the bitcode files if there are several. We must also link if we have a singleton .a
linker_inputs += extra_files_to_link
perform_link = len(linker_inputs) > 1 or shared.Settings.WASM_BACKEND
if not perform_link and not LEAVE_INPUTS_RAW:
is_bc = suffix(temp_files[0][1]) in BITCODE_ENDINGS
is_dylib = suffix(temp_files[0][1]) in DYNAMICLIB_ENDINGS
is_ar = shared.Building.is_ar(temp_files[0][1])
perform_link = not (is_bc or is_dylib) and is_ar
if perform_link:
logger.debug('linking: ' + str(linker_inputs))
# force archive contents to all be included, if just archives, or if linking shared modules
force_archive_contents = all(t.endswith(STATICLIB_ENDINGS) for _, t in temp_files) or shared.Settings.LINKABLE
# if EMCC_DEBUG=2 then we must link now, so the temp files are complete.
# if using the wasm backend, we might be using vanilla LLVM, which does not allow our fastcomp deferred linking opts.
# TODO: we could check if this is a fastcomp build, and still speed things up here
just_calculate = DEBUG != 2 and not shared.Settings.WASM_BACKEND
if shared.Settings.WASM_BACKEND:
# If LTO is enabled then use the -O opt level as the LTO level
if options.llvm_lto:
lto_level = options.opt_level
lto_level = 0
final = shared.Building.link_lld(linker_inputs, DEFAULT_FINAL, lto_level=lto_level)
final =, DEFAULT_FINAL, force_archive_contents=force_archive_contents, temp_files=misc_temp_files, just_calculate=just_calculate)
logger.debug('skipping linking: ' + str(linker_inputs))
_, temp_file = temp_files[0]
_, input_file = input_files[0]
final = in_temp(target_basename + '.bc')
if temp_file != input_file:
shutil.move(temp_file, final)
shutil.copyfile(temp_file, final)
_, input_file = input_files[0]
final = in_temp(input_file)
shutil.copyfile(input_file, final)
# exit block 'link'
if not shared.Settings.WASM_BACKEND:
with ToolchainProfiler.profile_block('post-link'):
logger.debug('saving intermediate processing steps to %s', shared.get_emscripten_temp_dir())
save_intermediate('basebc', 'bc')
# Optimize, if asked to
# remove LLVM debug if we are not asked for it
link_opts = [] if use_source_map(options) or shared.Settings.CYBERDWARF else ['-strip-debug']
if not shared.Settings.ASSERTIONS:
link_opts += ['-disable-verify']
# when verifying, LLVM debug info has some tricky linking aspects, and llvm-link will
# disable the type map in that case. we added linking to opt, so we need to do
# something similar, which we can do with a param to opt
link_opts += ['-disable-debug-info-type-map']
if options.llvm_lto is not None and options.llvm_lto >= 2 and optimizing(options.llvm_opts):
logger.debug('running LLVM opts as pre-LTO')
final = shared.Building.llvm_opt(final, options.llvm_opts, DEFAULT_FINAL)
save_intermediate('opt', 'bc')
# If we can LTO, do it before dce, since it opens up dce opportunities
if (not shared.Settings.LINKABLE) and options.llvm_lto and options.llvm_lto != 2:
if not shared.Building.can_inline():
# add a manual internalize with the proper things we need to be kept alive during lto
link_opts += shared.Building.get_safe_internalize() + ['-std-link-opts']
# execute it now, so it is done entirely before we get to the stage of legalization etc.
final = shared.Building.llvm_opt(final, link_opts, DEFAULT_FINAL)
save_intermediate('lto', 'bc')
link_opts = []
# At minimum remove dead functions etc., this potentially saves a lot in the size of the generated code (and the time to compile it)
link_opts += shared.Building.get_safe_internalize() + ['-globaldce']
if options.cfi:
if use_cxx:
# let llvm opt directly emit ll, to skip writing and reading all the bitcode
link_opts += ['-S']
final = shared.Building.llvm_opt(final, link_opts, get_final() + '.link.ll')
save_intermediate('linktime', 'll')
if len(link_opts) > 0:
final = shared.Building.llvm_opt(final, link_opts, DEFAULT_FINAL)
save_intermediate('linktime', 'bc')
if options.save_bc:
shutil.copyfile(final, options.save_bc)
# Prepare .ll for Emscripten
assert len(input_files) == 1
if options.save_bc:
save_intermediate('ll', 'll')
next = get_final() + '.ad.ll'
run_process([shared.PYTHON, shared.AUTODEBUGGER, final, next])
final = next
save_intermediate('autodebug', 'll')
assert not isinstance(final, list), 'we must have linked the final files, if linking was deferred, by this point'
# exit block 'post-link'
with ToolchainProfiler.profile_block('emscript'):
# Emscripten
logger.debug('LLVM => JS')
js_libraries = None
if options.js_libraries:
js_libraries = [os.path.abspath(lib) for lib in options.js_libraries]
if options.memory_init_file:
shared.Settings.MEM_INIT_METHOD = 1
assert shared.Settings.MEM_INIT_METHOD != 1
if embed_memfile(options):
shared.Settings.SUPPORT_BASE64_EMBEDDING = 1
final = shared.Building.emscripten(final, target + '.mem', js_libraries)
if shared.Settings.WASM_BACKEND:
# we also received wast and wasm at this stage
temp_basename = unsuffixed(final)
wasm_temp = temp_basename + '.wasm'
shutil.move(wasm_temp, wasm_binary_target)
if use_source_map(options):
shutil.move(wasm_temp + '.map', wasm_binary_target + '.map')
if shared.Settings.CYBERDWARF:
cd_target = final + '.cd'
shutil.move(cd_target, target + '.cd')
# exit block 'emscript'
log_time('emscript (llvm => executable code)')
with ToolchainProfiler.profile_block('source transforms'):
# Embed and preload files
if len(options.preload_files) or len(options.embed_files):
# Also, MEMFS is not aware of heap resizing feature in wasm, so if MEMFS and memory growth are used together, force
# no_heap_copy to be enabled.
if shared.Settings.ALLOW_MEMORY_GROWTH and not options.no_heap_copy:'Enabling --no-heap-copy because -s ALLOW_MEMORY_GROWTH=1 is being used with (pass --no-heap-copy to suppress this notification)')
options.no_heap_copy = True
logger.debug('setting up files')
file_args = ['--from-emcc', '--export-name=' + shared.Settings.EXPORT_NAME]
if len(options.preload_files):
file_args += options.preload_files
if len(options.embed_files):
file_args += options.embed_files
if len(options.exclude_files):
file_args += options.exclude_files
if options.use_preload_cache:
if options.no_heap_copy:
if shared.Settings.LZ4:
if options.use_preload_plugins:
file_code = run_process([shared.PYTHON, shared.FILE_PACKAGER, unsuffixed(target) + '.data'] + file_args, stdout=PIPE).stdout
options.pre_js = file_code + options.pre_js
# Apply pre and postjs files
if options.pre_js or options.post_js:
logger.debug('applying pre/postjses')
src = open(final).read()
final += '.pp.js'
if WINDOWS: # Avoid duplicating \r\n to \r\r\n when writing out.
if options.pre_js:
options.pre_js = options.pre_js.replace('\r\n', '\n')
if options.post_js:
options.post_js = options.post_js.replace('\r\n', '\n')
with open(final, 'w') as f:
# pre-js code goes right after the Module integration code (so it
# can use Module), we have a marker for it
f.write(src.replace('// {{PRE_JSES}}', options.pre_js))
options.pre_js = src = options.post_js = None
# Apply a source code transformation, if requested
if options.js_transform:
shutil.copyfile(final, final + '.tr.js')
final += '.tr.js'
posix = not shared.WINDOWS
logger.debug('applying transform: %s', options.js_transform)
shared.check_call(shared.Building.remove_quotes(shlex.split(options.js_transform, posix=posix) + [os.path.abspath(final)]))
js_transform_tempfiles = [final]
# exit block 'source transforms'
log_time('source transforms')
with ToolchainProfiler.profile_block('memory initializer'):
memfile = None
# for the wasm backend, use a memfile exactly when using pthreads (until
# we can remove this temporary hack)
if (not shared.Settings.WASM_BACKEND and (shared.Settings.MEM_INIT_METHOD > 0 or embed_memfile(options))) or \
(shared.Settings.WASM_BACKEND and shared.Settings.USE_PTHREADS):
if shared.Settings.MINIMAL_RUNTIME:
# Independent of whether user is doing -o a.html or -o a.js, generate the mem init file as a.mem (and not as a.html.mem or a.js.mem)
memfile = target.replace('.html', '.mem').replace('.js', '.mem')
memfile = target + '.mem'
if memfile:
if shared.Settings.WASM_BACKEND:
# For the wasm backend, we don't have any memory info in JS. All we need to do
# is set the memory initializer url.
src = open(final).read()
src = src.replace('var memoryInitializer = null;', 'var memoryInitializer = "%s";' % memfile)
open(final + '.mem.js', 'w').write(src)
final += '.mem.js'
# Non-wasm backend path: Strip the memory initializer out of the asmjs file
def repl(m):
# handle chunking of the memory initializer
s =
if len(s) == 0:
return '' # don't emit 0-size ones
membytes = [int(x or '0') for x in s.split(',')]
while membytes and membytes[-1] == 0:
if not membytes:
return ''
if shared.Settings.MEM_INIT_METHOD == 2:
# memory initializer in a string literal
return "memoryInitializer = '%s';" % shared.JS.generate_string_initializer(membytes)
open(memfile, 'wb').write(bytearray(membytes))
# Copy into temp dir as well, so can be run there too
shared.safe_copy(memfile, os.path.join(shared.get_emscripten_temp_dir(), os.path.basename(memfile)))
if not shared.Settings.WASM or not shared.Settings.MEM_INIT_IN_WASM:
return 'memoryInitializer = "%s";' % shared.JS.get_subresource_location(memfile, embed_memfile(options))
return ''
src = re.sub(shared.JS.memory_initializer_pattern, repl, open(final).read(), count=1)
open(final + '.mem.js', 'w').write(src)
final += '.mem.js'
src = None
js_transform_tempfiles[-1] = final # simple text substitution preserves comment line number mappings
if os.path.exists(memfile):
logger.debug('wrote memory initialization to %s', memfile)
logger.debug('did not see memory initialization')
if shared.Settings.USE_PTHREADS:
target_dir = os.path.dirname(os.path.abspath(target))
worker_output = os.path.join(target_dir, shared.Settings.PTHREAD_WORKER_FILE)
with open(worker_output, 'w') as f:
f.write(shared.read_and_preprocess(shared.path_from_root('src', 'worker.js'), expand_macros=True))
# Generate the fetch.js worker script for multithreaded emscripten_fetch() support if targeting pthreads.
if shared.Settings.FETCH and shared.Settings.USE_PTHREADS:
if shared.Settings.WASM_BACKEND:
logger.warning('Bug/TODO: Blocking calls to the fetch API do not currently work under WASM backend (')
shared.make_fetch_worker(final, shared.Settings.FETCH_WORKER_FILE)
# exit block 'memory initializer'
log_time('memory initializer')
optimizer = JSOptimizer(
with ToolchainProfiler.profile_block('js opts'):
# It is useful to run several js optimizer passes together, to save on unneeded unparsing/reparsing
if shared.Settings.DEAD_FUNCTIONS:
optimizer.queue += ['eliminateDeadFuncs']
optimizer.extra_info['dead_functions'] = shared.Settings.DEAD_FUNCTIONS
if options.opt_level >= 1 and options.js_opts:
logger.debug('running js post-opts')
if DEBUG == 2:
# Clean up the syntax a bit
optimizer.queue += ['noop']
def get_eliminate():
if shared.Settings.ALLOW_MEMORY_GROWTH:
return 'eliminateMemSafe'
return 'eliminate'
if options.opt_level >= 2:
optimizer.queue += [get_eliminate()]
# note that this happens before registerize/minification, which can obfuscate the name of 'label', which is tricky
optimizer.queue += ['aggressiveVariableElimination']
optimizer.queue += ['simplifyExpressions']
if shared.Settings.EMTERPRETIFY:
# emterpreter code will not run through a JS optimizing JIT, do more work ourselves
optimizer.queue += ['localCSE']
if shared.Settings.EMTERPRETIFY:
# add explicit label setting, as we will run aggressiveVariableElimination late, *after* 'label' is no longer notable by name
optimizer.queue += ['safeLabelSetting']
if options.opt_level >= 1 and options.js_opts:
if options.opt_level >= 2:
# simplify ifs if it is ok to make the code somewhat unreadable, and unless outlining (simplified ifs
# with commaified code breaks late aggressive variable elimination)
# do not do this with binaryen, as commaifying confuses binaryen call type detection (FIXME, in theory, but unimportant)
debugging = options.debug_level == 0 or options.profiling
if shared.Settings.SIMPLIFY_IFS and debugging and shared.Settings.OUTLINING_LIMIT == 0 and not shared.Settings.WASM:
optimizer.queue += ['simplifyIfs']
if shared.Settings.PRECISE_F32:
optimizer.queue += ['optimizeFrounds']
if options.js_opts:
if shared.Settings.SAFE_HEAP and not shared.Building.is_wasm_only():
optimizer.queue += ['safeHeap']
if shared.Settings.OUTLINING_LIMIT > 0:
optimizer.queue += ['outline']
optimizer.extra_info['sizeToOutline'] = shared.Settings.OUTLINING_LIMIT
if options.opt_level >= 2 and options.debug_level < 3:
if options.opt_level >= 3 or options.shrink_level > 0:
optimizer.queue += ['registerizeHarder']
optimizer.queue += ['registerize']
# NOTE: Important that this comes after registerize/registerizeHarder
if shared.Settings.ELIMINATE_DUPLICATE_FUNCTIONS and options.opt_level >= 2:
if shared.Settings.EVAL_CTORS and options.memory_init_file and not use_source_map(options) and not shared.Settings.WASM:
shared.Building.eval_ctors(final, memfile)
if options.js_opts:
# some compilation modes require us to minify later or not at all
if not shared.Settings.EMTERPRETIFY and not shared.Settings.WASM:
if options.opt_level >= 2:
optimizer.queue += ['asmLastOpts']
if shared.Settings.FINALIZE_ASM_JS:
optimizer.queue += ['last']
if options.use_closure_compiler == 2:
logger.debug('running closure')
# no need to add this to js_transform_tempfiles, because closure and
# debug_level > 0 are never simultaneously true
final = shared.Building.closure_compiler(final, pretty=options.debug_level >= 1)
log_time('js opts')
with ToolchainProfiler.profile_block('final emitting'):
if shared.Settings.EMTERPRETIFY:
emterpretify(js_target, optimizer, options)
# Remove some trivial whitespace
# TODO: do not run when compress has already been done on all parts of the code
# src = open(final).read()
# src = re.sub(r'\n+[ \n]*\n+', '\n', src)
# open(final, 'w').write(src)
# Bundle symbol data in with the cyberdwarf file
if shared.Settings.CYBERDWARF:
run_process([shared.PYTHON, shared.path_from_root('tools', ''), target + '.cd', target + '.symbols'])
if use_source_map(options) and not shared.Settings.WASM:
emit_js_source_maps(target, optimizer.js_transform_tempfiles)
# track files that will need native eols
generated_text_files_with_native_eols = []
if (options.separate_asm or shared.Settings.WASM) and not shared.Settings.WASM_BACKEND:
separate_asm_js(final, asm_target)
generated_text_files_with_native_eols += [asm_target]
if shared.Settings.WASM:
do_binaryen(target, asm_target, options, memfile, wasm_binary_target,
wasm_text_target, misc_temp_files, optimizer)
if shared.Settings.MODULARIZE:
# Run a final regex pass to clean up items that were not possible to optimize by Closure, or unoptimalities that were left behind
# by processing steps that occurred after Closure.
if shared.Settings.MINIMAL_RUNTIME == 2 and shared.Settings.USE_CLOSURE_COMPILER and options.debug_level == 0:
# Process .js runtime file
shared.run_process([shared.PYTHON, shared.path_from_root('tools', ''), final])
# Process .asm.js file
if not shared.Settings.WASM:
shared.run_process([shared.PYTHON, shared.path_from_root('tools', ''), asm_target])
# The JS is now final. Move it to its final location
shutil.move(final, js_target)
generated_text_files_with_native_eols += [js_target]
# If we were asked to also generate HTML, do that
if final_suffix == '.html':
generate_html(target, options, js_target, target_basename,
asm_target, wasm_binary_target,
memfile, optimizer)
if options.proxy_to_worker:
generate_worker_js(target, js_target, target_basename)
if embed_memfile(options) and memfile:
for f in generated_text_files_with_native_eols:
tools.line_endings.convert_line_endings_in_file(f, os.linesep, options.output_eol)
log_time('final emitting')
# exit block 'final emitting'
logger.debug('total time: %.2f seconds', (time.time() - start_time))
return 0
def parse_args(newargs):
options = EmccOptions()
settings_changes = []
should_exit = False
for i in range(len(newargs)):
# On Windows Vista (and possibly others), excessive spaces in the command line
# leak into the items in this array, so trim e.g. 'foo.cpp ' -> 'foo.cpp'
newargs[i] = newargs[i].strip()
if newargs[i].startswith('-O'):
# Let -O default to -O2, which is what gcc does.
options.requested_level = newargs[i][2:] or '2'
if options.requested_level == 's':
options.llvm_opts = ['-Os']
options.requested_level = 2
options.shrink_level = 1
elif options.requested_level == 'z':
options.llvm_opts = ['-Oz']
options.requested_level = 2
options.shrink_level = 2
options.opt_level = validate_arg_level(options.requested_level, 3, 'Invalid optimization level: ' + newargs[i], clamp=True)
elif newargs[i].startswith('--js-opts'):
options.js_opts = int(newargs[i + 1])
if options.js_opts:
options.force_js_opts = True
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('--llvm-opts'):
options.llvm_opts = parse_value(newargs[i + 1])
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('--llvm-lto'):
options.llvm_lto = int(newargs[i + 1])
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('--closure'):
options.use_closure_compiler = int(newargs[i + 1])
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('--js-transform'):
options.js_transform = newargs[i + 1]
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('--pre-js'):
options.pre_js += open(newargs[i + 1]).read() + '\n'
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('--post-js'):
options.post_js += open(newargs[i + 1]).read() + '\n'
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('--minify'):
assert newargs[i + 1] == '0', '0 is the only supported option for --minify; 1 has been deprecated'
options.debug_level = max(1, options.debug_level)
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('-g'):
requested_level = newargs[i][2:] or '3'
options.debug_level = validate_arg_level(requested_level, 4, 'Invalid debug level: ' + newargs[i])
options.requested_debug = newargs[i]
newargs[i] = ''
elif newargs[i] == '-profiling' or newargs[i] == '--profiling':
options.debug_level = 2
options.profiling = True
newargs[i] = ''
elif newargs[i] == '-profiling-funcs' or newargs[i] == '--profiling-funcs':
options.profiling_funcs = True
newargs[i] = ''
elif newargs[i] == '--tracing' or newargs[i] == '--memoryprofiler':
if newargs[i] == '--memoryprofiler':
options.memory_profiler = True
options.tracing = True
newargs[i] = ''
options.js_libraries.append(shared.path_from_root('src', 'library_trace.js'))
elif newargs[i] == '--emit-symbol-map':
options.emit_symbol_map = True
newargs[i] = ''
elif newargs[i] == '--bind':
options.bind = True
newargs[i] = ''
options.js_libraries.append(shared.path_from_root('src', 'embind', 'emval.js'))
options.js_libraries.append(shared.path_from_root('src', 'embind', 'embind.js'))
if options.default_cxx_std:
# Force C++11 for embind code, but only if user has not explicitly overridden a standard.
options.default_cxx_std = '-std=c++11'
elif newargs[i].startswith('-std=') or newargs[i].startswith('--std='):
# User specified a standard to use, clear Emscripten from specifying it.
options.default_cxx_std = None
elif newargs[i].startswith('--embed-file'):
options.embed_files.append(newargs[i + 1])
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('--preload-file'):
options.preload_files.append(newargs[i + 1])
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('--exclude-file'):
options.exclude_files.append(newargs[i + 1])
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('--use-preload-cache'):
options.use_preload_cache = True
newargs[i] = ''
elif newargs[i].startswith('--no-heap-copy'):
options.no_heap_copy = True
newargs[i] = ''
elif newargs[i].startswith('--use-preload-plugins'):
options.use_preload_plugins = True
newargs[i] = ''
elif newargs[i] == '--ignore-dynamic-linking':
options.ignore_dynamic_linking = True
newargs[i] = ''
elif newargs[i] == '-v':
shared.COMPILER_OPTS += ['-v']
newargs[i] = ''
elif newargs[i].startswith('--shell-file'):
options.shell_path = newargs[i + 1]
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('--source-map-base'):
options.source_map_base = newargs[i + 1]
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i].startswith('--js-library'):
options.js_libraries.append(newargs[i + 1])
newargs[i] = ''
newargs[i + 1] = ''
elif newargs[i] == '--remove-duplicates':
logger.warning('--remove-duplicates is deprecated as it is no longer needed. If you cannot link without it, file a bug with a testcase')
newargs[i] = ''
elif newargs[i] == '--jcache':
logger.error('jcache i