Minor cleanups to python linking code. NFC (#12201)

- Remove unused get_final function
- Inline trivial do_emscripten function
- Remove meaningless return values from building.link and building.link_lld
- Remove unused `just_calculate` argument from building.link

Author: sbc100

emcc.py

@@ -411,18 +411,6 @@ def find_output_arg(args):
   return specified_target, outargs
 
 
-def do_emscripten(infile, memfile):
-  # Run Emscripten
-  outfile = infile + '.o.js'
-  with ToolchainProfiler.profile_block('emscripten.py'):
-    emscripten.run(infile, outfile, memfile)
-
-  # Detect compilation crashes and errors
-  assert os.path.exists(outfile), 'Emscripten failed to generate .js'
-
-  return outfile
-
-
 def is_ar_file_with_missing_index(archive_file):
   # We parse the archive header outselves because llvm-nm --print-armap is slower and less
   # reliable.
@@ -2056,16 +2044,8 @@ def dedup_list(lst):
     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.
-      DEFAULT_FINAL = in_temp(target_basename + '.wasm')
-
-      def get_final():
-        global final
-        if isinstance(final, list):
-          final = DEFAULT_FINAL
-        return final
-
       logger.debug('linking: ' + str(linker_inputs))
+      final = in_temp(target_basename + '.wasm')
 
       # 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
@@ -2075,7 +2055,7 @@ def get_final():
       if shared.Settings.LLD_REPORT_UNDEFINED and shared.Settings.ERROR_ON_UNDEFINED_SYMBOLS:
         js_funcs = get_all_js_syms(misc_temp_files)
         log_time('JS symbol generation')
-      final = building.link_lld(linker_inputs, DEFAULT_FINAL, external_symbol_list=js_funcs)
+      building.link_lld(linker_inputs, final, external_symbol_list=js_funcs)
       # Special handling for when the user passed '-Wl,--version'.  In this case the linker
       # does not create the output file, but just prints its version and exits with 0.
       if '--version' in linker_inputs:
@@ -2100,7 +2080,9 @@ def get_final():
       if embed_memfile(options):
         shared.Settings.SUPPORT_BASE64_EMBEDDING = 1
 
-      final = do_emscripten(final, shared.replace_or_append_suffix(target, '.mem'))
+      emscripten.run(final, final + '.o.js', shared.replace_or_append_suffix(target, '.mem'))
+      final = final + '.o.js'
+
       save_intermediate('original')
 
       # we also received the wasm at this stage

tests/test_other.py

@@ -6377,32 +6377,6 @@ def test_canonicalize_nan_warning(self):
     self.assertContained('nan\n', out)
     self.assertContained('0x7fc01234\n', out)
 
-  @no_wasm_backend('tests our python linking logic')
-  def test_link_response_file_does_not_force_absolute_paths(self):
-    with_space = 'with space'
-    ensure_dir(with_space)
-
-    create_test_file(os.path.join(with_space, 'main.cpp'), '''
-      int main() {
-        return 0;
-      }
-    ''')
-
-    building.emcc(os.path.join(with_space, 'main.cpp'), ['-c', '-g'])
-
-    with chdir(with_space):
-      link_args = building.link(['main.cpp.o'], 'all.bc', just_calculate=True)
-
-    time.sleep(0.2) # Wait for Windows FS to release access to the directory
-    shutil.rmtree(with_space)
-
-    # We want only the relative path to be in the linker args, it should not be converted to an absolute path.
-    if hasattr(self, 'assertCountEqual'):
-      self.assertCountEqual(link_args, ['main.cpp.o'])
-    else:
-      # Python 2 compatibility
-      self.assertItemsEqual(link_args, ['main.cpp.o'])
-
   def test_memory_growth_noasm(self):
     self.run_process([EMCC, path_from_root('tests', 'hello_world.c'), '-O2', '-s', 'ALLOW_MEMORY_GROWTH=1'])
     src = open('a.out.js').read()

tools/building.py

@@ -456,17 +456,15 @@ def link_to_object(linker_inputs, target):
   if not Settings.LTO:
     link_lld(linker_inputs + ['--relocatable'], target)
   else:
-    link(linker_inputs, target)
+    link_bitcode(linker_inputs, target)
 
 
 def link_llvm(linker_inputs, target):
   # runs llvm-link to link things.
   cmd = [LLVM_LINK] + linker_inputs + ['-o', target]
   cmd = get_command_with_possible_response_file(cmd)
   print_compiler_stage(cmd)
-  output = run_process(cmd, stdout=PIPE).stdout
-  assert os.path.exists(target) and (output is None or 'Could not open input file' not in output), 'Linking error: ' + output
-  return target
+  check_call(cmd)
 
 
 def lld_flags_for_executable(external_symbol_list):
@@ -580,10 +578,9 @@ def link_lld(args, target, external_symbol_list=None):
   print_compiler_stage(cmd)
   cmd = get_command_with_possible_response_file(cmd)
   check_call(cmd)
-  return target
 
 
-def link(files, target, force_archive_contents=False, just_calculate=False):
+def link_bitcode(files, target, force_archive_contents=False):
   # "Full-featured" linking: looks into archives (duplicates lld functionality)
   actual_files = []
   # Tracking unresolveds is necessary for .a linking, see below.
@@ -716,13 +713,9 @@ def scan_archive_group(group):
   # Finish link
   # tolerate people trying to link a.so a.so etc.
   actual_files = unique_ordered(actual_files)
-  if just_calculate:
-    # just calculating; return the link arguments which is the final list of files to link
-    return actual_files
 
   logger.debug('emcc: linking: %s to %s', actual_files, target)
   link_llvm(actual_files, target)
-  return target
 
 
 def get_command_with_possible_response_file(cmd):