Allow DWARF with source map (#17484)

This allows generation of DWARF info and source map at the same time.
This adds an internal setting, `GENERATE_DWARF`, which is a counterpart
of existing `GENERATE_SORUCE_MAP`, because with only `DEBUG_LEVEL` we
now don't have a way to tell whether DWARF info is explicitly requested
or not, because we set `DEBUG_LEVEL` to 3 when source map is requested.

This adds some simple utility functions to `test_other.py` for DWARF and
source map verification. Also this enables `try_delete` to delete a list
of files.

Fixes #16699.

Author: aheejin

ChangeLog.md

@@ -20,6 +20,8 @@ See docs/process.md for more on how version tagging works.
 
 3.1.17
 ------
+- A source map file and DWARF info in the wasm can now be emitted at the same if
+  the user gives the both options: `-g -gsource-map`.
 - The `align` argument to the makeGetValue/makeSetValue JS library macros was
   removed (and replaced with an assert) as it had no uses internally and was
   removed (and replaced with an assert) as it had now uses internally and was

emcc.py

@@ -3177,6 +3177,8 @@ def consume_arg_file():
         else:
           # for 3+, report -g3 to clang as -g4 etc. are not accepted
           newargs[i] = '-g3'
+          if settings.DEBUG_LEVEL == 3:
+            settings.GENERATE_DWARF = 1
           if settings.DEBUG_LEVEL == 4:
             settings.GENERATE_SOURCE_MAP = 1
             diagnostics.warning('deprecated', 'please replace -g4 with -gsource-map')

src/settings_internal.js

@@ -202,6 +202,8 @@ var MEMORYPROFILER = false;
 
 var GENERATE_SOURCE_MAP = false;
 
+var GENERATE_DWARF = false;
+
 // Memory layout.  These are only used/set in RELOCATABLE builds.  Otherwise
 // memory layout is fixed in the wasm binary at link time.
 var STACK_BASE = 0;

tests/test_other.py

@@ -2425,20 +2425,59 @@ def compile_to_O0_executable(compile_args):
     self.assertEqual(no_size, line_size)
     self.assertEqual(line_size, full_size)
 
+  # Verify the existence (or lack thereof) of DWARF info in the given wasm file
+  def verify_dwarf(self, wasm_file, verify_func):
+    self.assertExists(wasm_file)
+    info = self.run_process([LLVM_DWARFDUMP, '--all', wasm_file], stdout=PIPE).stdout
+    verify_func('DW_TAG_subprogram', info) # Subprogram entry in .debug_info
+    verify_func('debug_line[0x', info) # Line table
+
+  def verify_dwarf_exists(self, wasm_file):
+    self.verify_dwarf(wasm_file, self.assertIn)
+
+  def verify_dwarf_does_not_exist(self, wasm_file):
+    self.verify_dwarf(wasm_file, self.assertNotIn)
+
+  # Verify if the given file name contains a source map
+  def verify_source_map_exists(self, map_file):
+    self.assertExists(map_file)
+    data = json.load(open(map_file))
+    # Simply check the existence of required sections
+    self.assertIn('version', data)
+    self.assertIn('sources', data)
+    self.assertIn('mappings', data)
+
   def test_dwarf(self):
     def compile_with_dwarf(args, output):
       # Test that -g enables dwarf info in object files and linked wasm
       self.run_process([EMXX, test_file('hello_world.cpp'), '-o', output, '-g'] + args)
-
-    def verify(output):
-      info = self.run_process([LLVM_DWARFDUMP, '--all', output], stdout=PIPE).stdout
-      self.assertIn('DW_TAG_subprogram', info) # Ensure there's a subprogram entry in .debug_info
-      self.assertIn('debug_line[0x', info) # Ensure there's a line table
-
     compile_with_dwarf(['-c'], 'a.o')
-    verify('a.o')
+    self.verify_dwarf_exists('a.o')
     compile_with_dwarf([], 'a.js')
-    verify('a.wasm')
+    self.verify_dwarf_exists('a.wasm')
+
+  def test_dwarf_with_source_map(self):
+    source_file = 'hello_world.cpp'
+    js_file = 'a.out.js'
+    wasm_file = 'a.out.wasm'
+    map_file = 'a.out.wasm.map'
+
+    # Generate only DWARF
+    self.emcc(test_file(source_file), ['-g'], js_file)
+    self.verify_dwarf_exists(wasm_file)
+    self.assertFalse(os.path.isfile(map_file))
+    try_delete([wasm_file, map_file, js_file])
+
+    # Generate only source map
+    self.emcc(test_file(source_file), ['-gsource-map'], js_file)
+    self.verify_dwarf_does_not_exist(wasm_file)
+    self.verify_source_map_exists(map_file)
+    try_delete([wasm_file, map_file, js_file])
+
+    # Generate DWARF with source map
+    self.emcc(test_file(source_file), ['-g', '-gsource-map'], js_file)
+    self.verify_dwarf_exists(wasm_file)
+    self.verify_source_map_exists(map_file)
 
   @unittest.skipIf(not scons_path, 'scons not found in PATH')
   @with_env_modify({'EMSCRIPTEN_ROOT': path_from_root()})

tools/building.py

@@ -1533,10 +1533,8 @@ def run_binaryen_command(tool, infile, outfile=None, args=None, debug=False, std
 
 
 def run_wasm_opt(infile, outfile=None, args=[], **kwargs):  # noqa
-  if outfile and (settings.DEBUG_LEVEL < 3 or settings.GENERATE_SOURCE_MAP):
-    # remove any dwarf debug info sections, if the debug level is <3, as
-    # we don't need them; also remove them if we use source maps (which are
-    # implemented separately from dwarf).
+  if outfile and not settings.GENERATE_DWARF:
+    # remove any dwarf debug info sections if dwarf is not requested.
     # note that we add this pass first, so that it doesn't interfere with
     # the final set of passes (which may generate stack IR, and nothing
     # should be run after that)

tools/tempfiles.py

@@ -11,9 +11,17 @@
 import sys
 
 
+def try_delete(pathnames):
+  if isinstance(pathnames, list):
+    for pathname in pathnames:
+      try_delete_one(pathname)
+  else:
+    try_delete_one(pathnames)
+
+
 # Attempts to delete given possibly nonexisting or read-only directory tree or filename.
 # If any failures occur, the function silently returns without throwing an error.
-def try_delete(pathname):
+def try_delete_one(pathname):
   try:
     os.unlink(pathname)
   except OSError: