Make source map names field optional

src/settings_internal.js

@@ -189,10 +189,14 @@ var EXPECT_MAIN = true;
 // If true, building against Emscripten's wasm heap memory profiler.
 var MEMORYPROFILER = false;
 
-// Set automatically to :
-// - 1 when using `-gsource-map`
-// - 2 when using `gsource-map=inline` (embed sources content in source map)
-var GENERATE_SOURCE_MAP = 0;
+// Source map related options. You can specify both like
+// -gsource-map=inline,names
+// -gsource-map
+var SOURCE_MAP_GENERATE = 0;
+// -gsource-map=inline
+var SOURCE_MAP_EMBED_SOURCE = 0;
+// -gsource-map=names
+var SOURCE_MAP_GENERATE_NAMES = 0;
 
 var GENERATE_DWARF = false;
 

test/test_other.py

@@ -9626,16 +9626,17 @@ def check_source_map_loc_info(address, func, loc):
       out = self.run_process(
           [emsymbolizer, '-s', 'sourcemap', 'test_dwarf.wasm', address],
           stdout=PIPE).stdout
-      self.assertIn(func, out)
+      if func:
+        self.assertIn(func, out)
       self.assertIn(loc, out)
 
     def do_tests(src):
       # 1. Test DWARF + source map together
       # For DWARF, we check for the full inlined info for both function names and
       # source locations. Source maps does not provide inlined info. So we only
       # check for the info of the outermost function.
-      self.run_process([EMCC, test_file(src), '-g', '-gsource-map', '-O1', '-o',
-                        'test_dwarf.js'])
+      self.run_process([EMCC, test_file(src), '-g', '-gsource-map=names', '-O1',
+                        '-o', 'test_dwarf.js'])
       check_dwarf_loc_info(out_to_js_call_addr, out_to_js_call_func,
                            out_to_js_call_loc)
       check_source_map_loc_info(out_to_js_call_addr, out_to_js_call_func[0],
@@ -9650,13 +9651,20 @@ def do_tests(src):
       # The addresses, function names, and source locations are the same across
       # the builds because they are relative offsets from the code section, so we
       # don't need to recompute them
-      self.run_process([EMCC, test_file(src), '-gsource-map', '-O1', '-o',
+      self.run_process([EMCC, test_file(src), '-gsource-map=names', '-O1', '-o',
                         'test_dwarf.js'])
       check_source_map_loc_info(out_to_js_call_addr, out_to_js_call_func[0],
                                 out_to_js_call_loc[0])
       check_source_map_loc_info(unreachable_addr, unreachable_func[0],
                                 unreachable_loc[0])
 
+      # 2-1. Test source map only with names section turned off
+      self.run_process([EMCC, test_file(src), '-gsource-map', '-O1', '-o',
+                        'test_dwarf.js'])
+      check_source_map_loc_info(out_to_js_call_addr, None,
+                                out_to_js_call_loc[0])
+      check_source_map_loc_info(unreachable_addr, None, unreachable_loc[0])
+
       # 3. Test DWARF only
       self.run_process([EMCC, test_file(src), '-g', '-O1', '-o',
                         'test_dwarf.js'])

tools/building.py

@@ -184,7 +184,7 @@ def lld_flags_for_executable(external_symbols):
   # those things.
   if   (not settings.GENERATE_DWARF and
         not settings.EMIT_SYMBOL_MAP and
-        not settings.GENERATE_SOURCE_MAP and
+        not settings.SOURCE_MAP_GENERATE and
         not settings.EMIT_NAME_SECTION and
         not settings.ASYNCIFY):
     cmd.append('--strip-debug')
@@ -1172,8 +1172,10 @@ def emit_wasm_source_map(wasm_file, map_file, final_wasm):
   if settings.SOURCE_MAP_PREFIXES:
     sourcemap_cmd += ['--prefix', *settings.SOURCE_MAP_PREFIXES]
 
-  if settings.GENERATE_SOURCE_MAP == 2:
+  if settings.SOURCE_MAP_EMBED_SOURCE:
     sourcemap_cmd += ['--sources']
+  if settings.SOURCE_MAP_GENERATE_NAMES:
+    sourcemap_cmd += ['--names']
 
   # TODO(sbc): Convert to using library internal API instead of running `main` here
   rtn = wasm_sourcemap.main(sourcemap_cmd)
@@ -1257,7 +1259,7 @@ def run_binaryen_command(tool, infile, outfile=None, args=None, debug=False, std
   # we must tell binaryen to update it
   # TODO: all tools should support source maps; wasm-ctor-eval does not atm,
   #       for example
-  if settings.GENERATE_SOURCE_MAP and outfile and tool in ['wasm-opt', 'wasm-emscripten-finalize', 'wasm-metadce']:
+  if settings.SOURCE_MAP_GENERATE and outfile and tool in ['wasm-opt', 'wasm-emscripten-finalize', 'wasm-metadce']:
     cmd += [f'--input-source-map={infile}.map']
     cmd += [f'--output-source-map={outfile}.map']
   if shared.SKIP_SUBPROCS:

tools/cmdline.py

@@ -365,13 +365,13 @@ def consume_arg_file():
         if debug_level == 0:
           # Set these explicitly so -g0 overrides previous -g on the cmdline
           settings.GENERATE_DWARF = 0
-          settings.GENERATE_SOURCE_MAP = 0
+          settings.SOURCE_MAP_GENERATE = 0
           settings.EMIT_NAME_SECTION = 0
         elif debug_level > 1:
           settings.EMIT_NAME_SECTION = 1
         # if we don't need to preserve LLVM debug info, do not keep this flag
         # for clang
-        if debug_level < 3 and not (settings.GENERATE_SOURCE_MAP or settings.SEPARATE_DWARF):
+        if debug_level < 3 and not (settings.SOURCE_MAP_GENERATE or settings.SEPARATE_DWARF):
           newargs[i] = '-g0'
         else:
           if debug_level == 3:
@@ -381,7 +381,7 @@ def consume_arg_file():
             # Lower this to -g3, and report a warning.
             newargs[i] = '-g3'
             diagnostics.warning('deprecated', 'please replace -g4 with -gsource-map')
-            settings.GENERATE_SOURCE_MAP = 1
+            settings.SOURCE_MAP_GENERATE = 1
           elif debug_level > 4:
             exit_with_error("unknown argument: '%s'", arg)
       else:
@@ -401,9 +401,15 @@ def consume_arg_file():
             settings.SEPARATE_DWARF = True
           settings.GENERATE_DWARF = 1
           settings.DEBUG_LEVEL = 3
-        elif debug_level in ['source-map', 'source-map=inline']:
-          settings.GENERATE_SOURCE_MAP = 1 if debug_level == 'source-map' else 2
+        elif debug_level.startswith('source-map'):
+          settings.SOURCE_MAP_GENERATE = 1
           newargs[i] = '-g'
+          if '=' in debug_level:
+            source_map_options = debug_level.split('=')[1].split(',')
+            if 'inline' in source_map_options:
+              settings.SOURCE_MAP_EMBED_SOURCE = 1
+            if 'names' in source_map_options:
+              settings.SOURCE_MAP_GENERATE_NAMES = 1
         elif debug_level == 'z':
           # Ignore `-gz`.  We don't support debug info compression.
           pass

tools/emscripten.py

@@ -565,7 +565,7 @@ def finalize_wasm(infile, outfile, js_syms):
   if infile != outfile:
     shutil.copy(infile, outfile)
 
-  if settings.GENERATE_SOURCE_MAP:
+  if settings.SOURCE_MAP_GENERATE:
     building.emit_wasm_source_map(infile, outfile + '.map', outfile)
     building.save_intermediate(outfile + '.map', 'base_wasm.map')
     base_url = settings.SOURCE_MAP_BASE + os.path.basename(outfile) + '.map'
@@ -601,7 +601,7 @@ def finalize_wasm(infile, outfile, js_syms):
 
   metadata = get_metadata(outfile, outfile, modify_wasm, args)
 
-  if settings.GENERATE_SOURCE_MAP:
+  if settings.SOURCE_MAP_GENERATE:
     building.save_intermediate(outfile + '.map', 'post_finalize.map')
 
   expected_exports = set(settings.EXPORTED_FUNCTIONS)

tools/link.py

@@ -764,7 +764,7 @@ def setup_sanitizers(options):
     if settings.MEMORY64:
       exit_with_error('MEMORY64 does not yet work with ASAN')
 
-  if settings.GENERATE_SOURCE_MAP:
+  if settings.SOURCE_MAP_GENERATE:
     settings.LOAD_SOURCE_MAP = 1
 
 
@@ -875,9 +875,9 @@ def phase_linker_setup(options, linker_args):  # noqa: C901, PLR0912, PLR0915
     settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$addOnInit', '$addOnExit']
 
   # TODO: support source maps with js_transform
-  if options.js_transform and settings.GENERATE_SOURCE_MAP:
+  if options.js_transform and settings.SOURCE_MAP_GENERATE:
     logger.warning('disabling source maps because a js transform is being done')
-    settings.GENERATE_SOURCE_MAP = 0
+    settings.SOURCE_MAP_GENERATE = 0
 
   # options.output_file is the user-specified one, target is what we will generate
   if options.output_file:
@@ -1633,9 +1633,9 @@ def limit_incoming_module_api():
   if settings.WASM_BIGINT:
     settings.LEGALIZE_JS_FFI = 0
 
-  if settings.SINGLE_FILE and settings.GENERATE_SOURCE_MAP:
+  if settings.SINGLE_FILE and settings.SOURCE_MAP_GENERATE:
     diagnostics.warning('emcc', 'SINGLE_FILE disables source map support (which requires a .map file)')
-    settings.GENERATE_SOURCE_MAP = 0
+    settings.SOURCE_MAP_GENERATE = 0
 
   if options.use_closure_compiler == 2 and not settings.WASM2JS:
     exit_with_error('closure compiler mode 2 assumes the code is asm.js, so not meaningful for wasm')
@@ -1760,7 +1760,7 @@ def get_full_import_name(name):
       diagnostics.warning('experimental', '-sJSPI (ASYNCIFY=2) is still experimental')
 
   if settings.WASM2JS:
-    if settings.GENERATE_SOURCE_MAP:
+    if settings.SOURCE_MAP_GENERATE:
       exit_with_error('wasm2js does not support source maps yet (debug in wasm for now)')
     if settings.MEMORY64:
       exit_with_error('wasm2js does not support MEMORY64')

tools/wasm-sourcemap.py

@@ -45,6 +45,7 @@ def parse_args(args):
   parser.add_argument('--dwarfdump', help="path to llvm-dwarfdump executable")
   parser.add_argument('--dwarfdump-output', nargs='?', help=argparse.SUPPRESS)
   parser.add_argument('--basepath', help='base path for source files, which will be relative to this')
+  parser.add_argument('--names', action='store_true', help='generate function names in the names field')
   return parser.parse_args(args)
 
 
@@ -399,12 +400,17 @@ def read_dwarf_info(wasm, options):
     logger.debug('Reading DWARF information from %s' % wasm)
     if not os.path.exists(options.dwarfdump):
       utils.exit_with_error('llvm-dwarfdump not found: ' + options.dwarfdump)
-    # We need only three tags in the debug info: DW_TAG_compile_unit for
-    # source location, and DW_TAG_subprogram and DW_TAG_inlined_subroutine
-    # for the function ranges.
-    dwarfdump_cmd = [options.dwarfdump, '-debug-info', '-debug-line', wasm,
-                     '-t', 'DW_TAG_compile_unit', '-t', 'DW_TAG_subprogram',
-                     '-t', 'DW_TAG_inlined_subroutine']
+    dwarfdump_cmd = [options.dwarfdump, '-debug-info', '-debug-line', wasm]
+    if options.names:
+      # We need only three tags in the debug info: DW_TAG_compile_unit for
+      # source location, and DW_TAG_subprogram and DW_TAG_inlined_subroutine
+      # for the function ranges.
+      dwarfdump_cmd += ['-t', 'DW_TAG_compile_unit', '-t', 'DW_TAG_subprogram',
+                        '-t', 'DW_TAG_inlined_subroutine']
+    else:
+      # We only need the top-level DW_TAG_compile_unit tags when not generating
+      # the names field
+      dwarfdump_cmd += ['--recurse-depth=0']
     proc = shared.check_call(dwarfdump_cmd, stdout=shared.PIPE)
     output = proc.stdout
   else:
@@ -480,7 +486,10 @@ def read_dwarf_info(wasm, options):
   # return entries sorted by the address field
   entries = sorted(entries, key=lambda entry: entry['address'])
 
-  func_ranges = extract_func_ranges(debug_info)
+  if options.names:
+    func_ranges = extract_func_ranges(debug_info)
+  else:
+    func_ranges = []
   return entries, func_ranges