DEMANGLE_SUPPORT option to use libcxxabi's demangler in stackTrace()

5 files changed, 64 insertions, 5 deletions

diff --git a/emcc b/emcc
index 15cfbb7b..f6180f20 100755
--- a/emcc
+++ b/emcc
@@ -1390,6 +1390,11 @@ try:
     next_arg_index += 1
     shared.Settings.EXPORTED_FUNCTIONS += ['_stbi_load', '_stbi_load_from_memory', '_stbi_image_free']
 
+  forced_stdlibs = []
+  if shared.Settings.DEMANGLE_SUPPORT:
+    shared.Settings.EXPORTED_FUNCTIONS += ['___cxa_demangle']
+    forced_stdlibs += ['libcxxabi']
+
   if type(shared.Settings.EXPORTED_FUNCTIONS) in (list, tuple):
     # always need malloc and free to be kept alive and exported, for internal use and other modules
     for required_export in ['_malloc', '_free']:
@@ -1536,7 +1541,7 @@ try:
   if not LEAVE_INPUTS_RAW and \
      not shared.Settings.BUILD_AS_SHARED_LIB and \
      not shared.Settings.SIDE_MODULE: # shared libraries/side modules link no C libraries, need them in parent
-    extra_files_to_link = system_libs.calculate([f for _, f in sorted(temp_files)], in_temp, stdout, stderr)
+    extra_files_to_link = system_libs.calculate([f for _, f in sorted(temp_files)], in_temp, stdout, stderr, forced=forced_stdlibs)
   else:
     extra_files_to_link = []
 
diff --git a/src/preamble.js b/src/preamble.js
index 1541075e..7ac9b549 100644
--- a/src/preamble.js
+++ b/src/preamble.js
@@ -778,6 +778,25 @@ function stringToUTF32(str, outPtr) {
 Module['stringToUTF32'] = stringToUTF32;
 
 function demangle(func) {
+  var hasLibcxxabi = !!Module['___cxa_demangle'];
+  if (hasLibcxxabi) {
+    try {
+      var buf = _malloc(func.length);
+      writeStringToMemory(func.substr(1), buf);
+      var status = _malloc(4);
+      var ret = Module['___cxa_demangle'](buf, 0, 0, status);
+      if (getValue(status, 'i32') === 0 && ret) {
+        return Pointer_stringify(ret);
+      }
+      // otherwise, libcxxabi failed, we can try ours which may return a partial result
+    } catch(e) {
+      // failure when using libcxxabi, we can try ours which may return a partial result
+    } finally {
+      if (buf) _free(buf);
+      if (status) _free(status);
+      if (ret) _free(ret);
+    }
+  }
   var i = 3;
   // params, etc.
   var basicTypes = {
@@ -909,6 +928,7 @@ function demangle(func) {
       return ret + flushList();
     }
   }
+  var final = func;
   try {
     // Special-case the entry point, since its name differs from other name mangling.
     if (func == 'Object._main' || func == '_main') {
@@ -922,10 +942,14 @@ function demangle(func) {
       case 'n': return 'operator new()';
       case 'd': return 'operator delete()';
     }
-    return parse();
+    final = parse();
   } catch(e) {
-    return func;
+    final += '?';
+  }
+  if (final.indexOf('?') >= 0 && !hasLibcxxabi) {
+    Runtime.warnOnce('A problem occurred in builtin C++ name demangling; build with  -s DEMANGLE_SUPPORT=1  to link in libcxxabi demangling');
   }
+  return final;
 }
 
 function demangleAll(text) {
diff --git a/src/settings.js b/src/settings.js
index 14077efd..b7947ac8 100644
--- a/src/settings.js
+++ b/src/settings.js
@@ -231,6 +231,9 @@ var LABEL_FUNCTION_FILTERS = []; // Filters for function label debug.
                                  // When the array is empty, the filter is disabled.
 var EXCEPTION_DEBUG = 0; // Print out exceptions in emscriptened code. Does not work in asm.js mode
 
+var DEMANGLE_SUPPORT = 0; // If 1, build in libcxxabi's full c++ demangling code, to allow stackTrace()
+                          // to emit fully proper demangled c++ names
+
 var LIBRARY_DEBUG = 0; // Print out when we enter a library call (library*.js). You can also unset
                        // Runtime.debug at runtime for logging to cease, and can set it when you
                        // want it back. A simple way to set it in C++ is
diff --git a/tests/test_other.py b/tests/test_other.py
index b4e6a620..398975fc 100644
--- a/tests/test_other.py
+++ b/tests/test_other.py
@@ -2191,6 +2191,32 @@ void wakaw::Cm::RasterBase<wakaw::watwat::Polocator?>(unsigned int*, unsigned in
     assert 'one(int)' in output
     assert 'two(char)' in output
 
+    # full demangle support
+
+    Popen([PYTHON, EMCC, 'src.cpp', '-s', 'LINKABLE=1', '-s', 'DEMANGLE_SUPPORT=1']).communicate()
+    output = run_js('a.out.js')
+    self.assertContained('''operator new(unsigned int)
+main()
+f2()
+abcdabcdabcd(int)
+abcdabcdabcd(int)
+test(char, short, int, float, double, void*, int*, char*)
+test::moarr(char, short, long, float, double, void*, int*, char*)
+Waka::f::a23412341234::point()
+void Foo<int>()
+void Foo<int, double>(int)
+void Foo::Bar<5>()
+__cxxabiv1::__si_class_type_info::search_below_dst(__cxxabiv1::__dynamic_cast_info*, void const*, int, bool) const
+parseword(char const*&, int, int&)
+multi(wchar_t, signed char, unsigned char, unsigned short, unsigned int, unsigned long, long long, unsigned long long, ...)
+a(int [32], char (*) [5])
+FWakaGLXFleeflsMarfoo::FWakaGLXFleeflsMarfoo(unsigned int, unsigned int, unsigned int, void const*, bool, unsigned int, unsigned int)
+void wakaw::Cm::RasterBase<wakaw::watwat::Polocator>::merbine1<wakaw::Cm::RasterBase<wakaw::watwat::Polocator>::OR>(unsigned int const*, unsigned int)
+''', output)
+    # test for multiple functions in one stack trace
+    assert 'one(int)' in output
+    assert 'two(char)' in output
+
   def test_module_exports_with_closure(self):
     # This test checks that module.export is retained when JavaScript is minified by compiling with --closure 1
     # This is important as if module.export is not present the Module object will not be visible to node.js
diff --git a/tools/system_libs.py b/tools/system_libs.py
index 9b63af09..700f219e 100644
--- a/tools/system_libs.py
+++ b/tools/system_libs.py
@@ -13,7 +13,7 @@ def call_process(cmd):
   if proc.returncode != 0:
     raise CalledProcessError(proc.returncode, cmd)
 
-def calculate(temp_files, in_temp, stdout_, stderr_):
+def calculate(temp_files, in_temp, stdout_, stderr_, forced=[]):
   global stdout, stderr
   stdout = stdout_
   stderr = stderr_
@@ -455,7 +455,8 @@ def calculate(temp_files, in_temp, stdout_, stderr_):
   # You can provide 1 to include everything, or a comma-separated list with the ones you want
   force = os.environ.get('EMCC_FORCE_STDLIBS')
   force_all = force == '1'
-  force = set((force or '').split(','))
+  force = set((force or '').split(',') + forced)
+  if force: logging.debug('forcing stdlibs: ' + str(force))
 
   # Scan symbols
   symbolses = map(lambda temp_file: shared.Building.llvm_nm(temp_file), temp_files)