Remove fastc-only ELIMINATE_DUPLICATE_FUNCTIONS option. See #11860

Author: kripken

emcc.py

@@ -1869,9 +1869,6 @@ def include_and_export(name):
         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
-      if shared.Settings.ELIMINATE_DUPLICATE_FUNCTIONS:
-        diagnostics.warning('emcc', 'for wasm there is no need to set ELIMINATE_DUPLICATE_FUNCTIONS, the binaryen optimizer does it automatically')
-        shared.Settings.ELIMINATE_DUPLICATE_FUNCTIONS = 0
       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')
@@ -2695,12 +2692,6 @@ def get_eliminate():
           else:
             optimizer.queue += ['registerize']
 
-        # NOTE: Important that this comes after registerize/registerizeHarder
-        if shared.Settings.ELIMINATE_DUPLICATE_FUNCTIONS and shared.Settings.OPT_LEVEL >= 2:
-          optimizer.flush()
-          building.eliminate_duplicate_funcs(final)
-          save_intermediate('dfe')
-
       if shared.Settings.EVAL_CTORS and options.memory_init_file and not use_source_map(options) and not shared.Settings.WASM:
         optimizer.flush()
         building.eval_ctors(final, memfile)

site/source/docs/optimizing/Optimizing-Code.rst

@@ -86,7 +86,6 @@ The following compiler settings can help (see ``src/settings.js`` for more detai
 - Disable inlining when possible, using ``-s INLINING_LIMIT=1``. Compiling with -Os or -Oz generally avoids inlining too. (Inlining can make code faster, though, so use this carefully.)
 - You can use the ``-s FILESYSTEM=0`` option to disable bundling of filesystem support code (the compiler should optimize it out if not used, but may not always succeed). This can be useful if you are building a pure computational library, for example.
 - The ``ENVIRONMENT`` flag lets you specify that the output will only run on the web, or only run in node.js, etc. This prevents the compiler from emitting code to support all possible runtime environments, saving ~2KB.
-- You can use ``ELIMINATE_DUPLICATE_FUNCTIONS`` to remove duplicate functions, which C++ templates often create. (This is already done by default for wasm, in ``-O1`` and above.)
 
 LTO
 ===

src/settings.js

@@ -1412,19 +1412,6 @@ var PTHREADS_DEBUG = 0;
 // If true, building against Emscripten's asm.js/wasm heap memory profiler.
 var MEMORYPROFILER = 0;
 
-// Duplicate function elimination. This coalesces function bodies that are
-// identical, which can happen e.g. if two methods have different C/C++ or LLVM
-// types, but end up identical at the asm.js level (all pointers are the same as
-// int32_t in asm.js, for example).
-//
-// This option is quite slow to run, as it processes and hashes all methods in
-// the codebase in multiple passes.
-//
-// [fastcomp-only]
-var ELIMINATE_DUPLICATE_FUNCTIONS = 0; // disabled by default
-var ELIMINATE_DUPLICATE_FUNCTIONS_DUMP_EQUIVALENT_FUNCTIONS = 0;
-var ELIMINATE_DUPLICATE_FUNCTIONS_PASSES = 5;
-
 // This tries to evaluate global ctors at compile-time, applying their effects
 // into the mem init file. This saves running code during startup, and also
 // allows removing the global ctor functions and other code that only they used,

tests/fuzz/25.c

@@ -1785,8 +1785,3 @@ XXX max block depth: 5
 XXX percentage a fresh-made variable is used: 17.8
 XXX percentage an existing variable is used: 82.2
 ********************* end of statistics **********************/
-
-
-// /usr/bin/python /Users/achoudhury/Code/emscripten/emscripten/emcc -Oz --llvm-opts 1 /Users/achoudhury/Code/emscripten/emscripten/tests/fuzz/temp_fuzzcode28225_.cpp -o /Users/achoudhury/Code/emscripten/emscripten/tests/fuzz/fuzz.cpp -I /usr/local/Cellar/csmith/2.2.0/include/csmith-2.2.0/runtime -s ELIMINATE_DUPLICATE_FUNCTIONS=1 --emit-symbol-map -w -s MAIN_MODULE=1 -s EMTERPRETIFY=1 -s EMTERPRETIFY_WHITELIST=["_main"]
-
-

tests/test_core.py

@@ -264,18 +264,6 @@ class TestCoreBase(RunnerCore):
   def is_wasm2js(self):
     return self.is_wasm_backend() and not self.get_setting('WASM')
 
-  # whether the test mode supports duplicate function elimination in js
-  def supports_js_dfe(self):
-    # wasm does this when optimizing anyhow, and the wasm backend always
-    # optimizes the wasm even if it does wasm2js later
-    if self.is_wasm() or self.is_wasm_backend():
-      return False
-    supported_opt_levels = ['-O2', '-O3', '-Oz', '-Os']
-    for opt_level in supported_opt_levels:
-      if opt_level in self.emcc_args:
-        return True
-    return False
-
   # Use closure in some tests for some additional coverage
   def maybe_closure(self):
     if '-g' not in self.emcc_args and ('-O2' in self.emcc_args or '-Os' in self.emcc_args):
@@ -6258,14 +6246,6 @@ def test():
 
     test()
 
-    if self.supports_js_dfe():
-      print("Testing poppler with ELIMINATE_DUPLICATE_FUNCTIONS set to 1", file=sys.stderr)
-      num_original_funcs = self.count_funcs('src.cpp.o.js')
-      self.set_setting('ELIMINATE_DUPLICATE_FUNCTIONS', 1)
-      test()
-      # Make sure that DFE ends up eliminating more than 200 functions (if we can view source)
-      assert (num_original_funcs - self.count_funcs('src.cpp.o.js')) > 200
-
   @needs_make('make')
   @is_slow_test
   def test_openjpeg(self):
@@ -8290,14 +8270,6 @@ def test(assert_returncode=0):
       print('ENVIRONMENT =', self.get_setting('ENVIRONMENT'))
       test()
 
-  def test_dfe(self):
-    if not self.supports_js_dfe():
-      self.skipTest('dfe-only')
-    self.set_setting('ELIMINATE_DUPLICATE_FUNCTIONS', 1)
-    self.do_run_in_out_file_test('tests', 'core', 'test_hello_world')
-    self.emcc_args += ['-g2'] # test for issue #6331
-    self.do_run_in_out_file_test('tests', 'core', 'test_hello_world')
-
   def test_postrun_exception(self):
     # verify that an exception thrown in postRun() will not trigger the
     # compilation failed handler, and will be printed to stderr.

tests/test_other.py

@@ -9035,7 +9035,7 @@ def test_minimal_runtime_code_size(self):
                                '-DNDEBUG',
                                '-ffast-math']
 
-    asmjs = ['-s', 'WASM=0', '--separate-asm', '-s', 'ELIMINATE_DUPLICATE_FUNCTIONS=1', '--memory-init-file', '1']
+    asmjs = ['-s', 'WASM=0', '--separate-asm', '-s', '--memory-init-file', '1']
     wasm2js = ['-s', 'WASM=0', '--memory-init-file', '1']
 
     hello_world_sources = [path_from_root('tests', 'small_hello_world.c'),

tools/building.py

@@ -986,11 +986,6 @@ def eval_ctors(js_file, binary_file, binaryen_bin='', debug_info=False):
   check_call(cmd)
 
 
-def eliminate_duplicate_funcs(filename):
-  from . import duplicate_function_eliminator
-  duplicate_function_eliminator.eliminate_duplicate_funcs(filename)
-
-
 def calculate_reachable_functions(infile, initial_list, can_reach=True):
   with ToolchainProfiler.profile_block('calculate_reachable_functions'):
     from . import asm_module