Deprecate unused --llvm-opts command line argument (#13750)

This option was already essentially ignored is the value of
`options.llvm_opts` was written but never read by the compiler driver.

The last use of this option was removed back in #11967 but this went
unnoticed.

Author: sbc100

ChangeLog.md

@@ -23,6 +23,9 @@ Current Trunk
 - Lists that are passed on the command line can now skip the opening an closing
   braces, allowing for simpler, more readable settings.  e.g.
     `-s EXPORTED_FUNCTIONS=foo,bar`
+- Remove/deprecate no longer used `--llvm-opts` command line option.  Any
+  arguments not processed by emcc will be passed through to clang directly
+  these days.
 - Values returned from `sysconf` now more closely match the definitions found in
   header files and in upstream musl (#13713).
 - `DISABLE_EXCEPTION_CATCHING=2` is now deprecated since it can be inferred from

docs/emcc.txt

@@ -215,26 +215,6 @@ Options that are modified or new in *emcc* are listed below:
      happens in "-O2" and above, and when no "-g" option was specified
      to prevent minification.
 
-"--llvm-opts <level>"
-   [compile+link] Enables LLVM optimizations, relevant when we call
-   the LLVM optimizer (which is done when building source files to
-   object code). Possible "level" values are:
-
-      * "0": No LLVM optimizations (default in -O0).
-
-      * "1": LLVM "-O1" optimizations (default in -O1).
-
-      * "2": LLVM "-O2" optimizations.
-
-      * "3": LLVM "-O3" optimizations (default in -O2+).
-
-   You can also specify arbitrary LLVM options, e.g.:
-
-      --llvm-opts "['-O3', '-somethingelse']"
-
-   You normally don't need to specify this option, as "-O" with an
-   optimization level will set a good value.
-
 "-flto"
    [compile+link] Enables link-time optimizations (LTO).
 

emcc.py

@@ -233,7 +233,6 @@ def __init__(self):
     self.profiling_funcs = False
     self.tracing = False
     self.emit_symbol_map = False
-    self.llvm_opts = None
     self.use_closure_compiler = None
     self.closure_args = []
     self.js_transform = None
@@ -1010,11 +1009,6 @@ def uniquename(name):
     if options.thread_profiler:
       options.post_js += open(shared.path_from_root('src', 'threadprofiler.js')).read() + '\n'
 
-    if options.llvm_opts is None:
-      options.llvm_opts = LLVM_OPT_LEVEL[shared.Settings.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 = shared.Settings.OPT_LEVEL >= 2
 
@@ -2559,12 +2553,10 @@ def consume_arg_file():
       # Let -O default to -O2, which is what gcc does.
       options.requested_level = arg[2:] or '2'
       if options.requested_level == 's':
-        options.llvm_opts = ['-Os']
         options.requested_level = 2
         shared.Settings.SHRINK_LEVEL = 1
         settings_changes.append('INLINING_LIMIT=50')
       elif options.requested_level == 'z':
-        options.llvm_opts = ['-Oz']
         options.requested_level = 2
         shared.Settings.SHRINK_LEVEL = 2
         settings_changes.append('INLINING_LIMIT=25')
@@ -2573,7 +2565,7 @@ def consume_arg_file():
       logger.warning('--js-opts ignored when using llvm backend')
       consume_arg()
     elif check_arg('--llvm-opts'):
-      options.llvm_opts = parse_value(consume_arg(), expect_list=True)
+      diagnostics.warning('deprecated', '--llvm-opts is deprecated.  All non-emcc args are passed through to clang.')
     elif arg.startswith('-flto'):
       if '=' in arg:
         shared.Settings.LTO = arg.split('=')[1]

site/source/docs/compiling/Building-Projects.rst

@@ -145,8 +145,6 @@ However, sometimes you may want slightly different optimizations on certain file
 .. note:: Unfortunately each build-system defines its own mechanisms for setting compiler and optimization methods. **You will need to work out the correct approach to set the LLVM optimization flags for your system**.
 
   - Some build systems have a flag like ``./configure --enable-optimize``.
-  - You can control whether LLVM optimizations are run using ``--llvm-opts N`` where N is an integer in the range 0-3. Sending ``-O2 --llvm-opts 0`` to *emcc* during all compilation stages will disable LLVM optimizations but utilize JavaScript optimizations. This can be useful when debugging a build failure.
-
 
 JavaScript/WebAssembly optimizations are specified in the final step (sometimes called "link", as that step typically also links together a bunch of files that are all compiled together into one JavaScript/WebAssembly output). For example, to compile with :ref:`-O1 <emcc-O1>`:
 

site/source/docs/tools_reference/emcc.rst

@@ -203,23 +203,6 @@ Options that are modified or new in *emcc* are listed below:
 
   .. note:: This is only relevant when :term:`minifying` global names, which happens in ``-O2`` and above, and when no ``-g`` option was specified to prevent minification.
 
-.. _emcc-llvm-opts:
-
-``--llvm-opts <level>``
-  [compile+link]
-  Enables LLVM optimizations, relevant when we call the LLVM optimizer (which is done when building source files to object code). Possible ``level`` values are:
-
-    - ``0``: No LLVM optimizations (default in -O0).
-    - ``1``: LLVM ``-O1`` optimizations (default in -O1).
-    - ``2``: LLVM ``-O2`` optimizations.
-    - ``3``: LLVM ``-O3`` optimizations (default in -O2+).
-
-  You can also specify arbitrary LLVM options, e.g.::
-
-    --llvm-opts "['-O3', '-somethingelse']"
-
-  You normally don't need to specify this option, as ``-O`` with an optimization level will set a good value.
-
 .. _emcc-lto:
 
 ``-flto``

tests/fuzz/23.cpp

@@ -476,5 +476,5 @@ int main (int argc, char* argv[])
     return 0;
 }
 
-// /usr/bin/python Dev/emscripten/emcc -O2 --llvm-opts 3 Dev/emscripten/tests/fuzz/temp_fuzzcode29254_.cpp -o Dev/emscripten/tests/fuzz/temp_fuzzcode29254_.js -I Dev/csmith/runtime
+// /usr/bin/python Dev/emscripten/emcc -O2 Dev/emscripten/tests/fuzz/temp_fuzzcode29254_.cpp -o Dev/emscripten/tests/fuzz/temp_fuzzcode29254_.js -I Dev/csmith/runtime
 

tests/fuzz/24.cpp

@@ -4808,5 +4808,5 @@ XXX percentage an existing variable is used: 85.1
 ********************* end of statistics **********************/
 
 
-// /usr/bin/python /media/alon/2f9a30d7-6124-42d9-87c5-3c80cb70ec54/home/alon/Dev/emscripten/emcc -O3 --llvm-opts 3 newfail_11275_1.cpp -I /home/alon/Dev/csmith/runtime -s ALLOW_MEMORY_GROWTH=1 -s EMTERPRETIFY=1 -s EMTERPRETIFY_WHITELIST='["_main"]'
+// /usr/bin/python /media/alon/2f9a30d7-6124-42d9-87c5-3c80cb70ec54/home/alon/Dev/emscripten/emcc -O3 newfail_11275_1.cpp -I /home/alon/Dev/csmith/runtime -s ALLOW_MEMORY_GROWTH=1 -s EMTERPRETIFY=1 -s EMTERPRETIFY_WHITELIST='["_main"]'
 

tests/fuzz/csmith_driver.py

@@ -55,10 +55,6 @@
       opts = '-Oz'
   print('opt level:', opts)
 
-  llvm_opts = []
-  if random.random() < 0.5:
-    llvm_opts = ['--llvm-opts', str(random.randint(0, 3))]
-
   print('Tried %d, notes: %s' % (tried, notes))
   print('1) Generate source')
   extra_args = []
@@ -115,7 +111,7 @@
 
   def try_js(args=[]):
     shared.try_delete(filename + '.js')
-    js_args = [shared.EMCC, fullname, '-o', filename + '.js'] + [opts] + llvm_opts + CSMITH_CFLAGS + args + ['-w']
+    js_args = [shared.EMCC, fullname, '-o', filename + '.js'] + [opts] + CSMITH_CFLAGS + args + ['-w']
     if TEST_BINARYEN:
       if random.random() < 0.5:
         js_args += ['-g']

tests/test_core.py

@@ -6587,7 +6587,7 @@ def test_demangle_stacks(self, extra_args):
     self.set_setting('DEMANGLE_SUPPORT')
     self.set_setting('ASSERTIONS')
     # ensure function names are preserved
-    self.emcc_args += ['--profiling-funcs', '--llvm-opts', '0']
+    self.emcc_args += ['--profiling-funcs']
     self.do_core_test('test_demangle_stacks.cpp', assert_returncode=NON_ZERO)
     if not self.has_changed_setting('ASSERTIONS'):
       print('without assertions, the stack is not printed, but a message suggesting assertions is')
@@ -6596,9 +6596,7 @@ def test_demangle_stacks(self, extra_args):
 
   def test_demangle_stacks_symbol_map(self):
     self.set_setting('DEMANGLE_SUPPORT')
-    if '-O' in str(self.emcc_args) and '-O0' not in self.emcc_args and '-O1' not in self.emcc_args and '-g' not in self.emcc_args:
-      self.emcc_args += ['--llvm-opts', '0']
-    else:
+    if '-O' not in str(self.emcc_args) or '-O0' in self.emcc_args or '-O1' in self.emcc_args or '-g' in self.emcc_args:
       self.skipTest("without opts, we don't emit a symbol map")
     self.emcc_args += ['--emit-symbol-map']
     self.do_runf(test_file('core', 'test_demangle_stacks.cpp'), 'abort', assert_returncode=NON_ZERO)