Function get_clang_flags

tools/compile.py:33–80

(user_args)

def get_clang_flags(user_args):
  flags = get_target_flags()

  # if exception catching is disabled, we can prevent that code from being
  # generated in the frontend
  if settings.DISABLE_EXCEPTION_CATCHING and not settings.WASM_EXCEPTIONS:
    flags.append('-fignore-exceptions')

  if settings.INLINING_LIMIT:
    flags.append('-fno-inline-functions')

  if settings.PTHREADS:
    if '-pthread' not in user_args:
      flags.append('-pthread')
  elif settings.SHARED_MEMORY:
    if '-matomics' not in user_args:
      flags.append('-matomics')
    if '-mbulk-memory' not in user_args:
      flags.append('-mbulk-memory')

  if (settings.MAIN_MODULE or settings.SIDE_MODULE) and '-fPIC' not in user_args:
    flags.append('-fPIC')

  if settings.MAIN_MODULE or settings.SIDE_MODULE or settings.LINKABLE or '-fPIC' in user_args:
    if not any(a.startswith('-fvisibility') for a in user_args):
      # For relocatable code we default to visibility=default in emscripten even
      # though the upstream backend defaults visibility=hidden.  This matches the
      # expectations of C/C++ code in the wild which expects undecorated symbols
      # to be exported to other DSO's by default.
      flags.append('-fvisibility=default')

  if settings.LTO:
    if not any(a.startswith('-flto') for a in user_args):
      flags.append('-flto=' + settings.LTO)
    # setjmp/longjmp handling using Wasm EH
    # For non-LTO, '-mllvm -wasm-enable-eh' added in
    # building.llvm_backend_args() sets this feature in clang. But in LTO, the
    # argument is added to wasm-ld instead, so clang needs to know that EH is
    # enabled so that it can be added to the attributes in LLVM IR.
    if settings.SUPPORT_LONGJMP == 'wasm':
      flags.append('-mexception-handling')

  else:
    # In LTO mode these args get passed instead at link time when the backend runs.
    for a in building.llvm_backend_args():
      flags += ['-mllvm', a]

  return flags


@memoize