[Mac/GN] Use a special .symbol_resolver to help load the ASan dynamic library.

build/config/sanitizers/generate_asan_runtime_stubs.py

+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import optparse
+import os
+import subprocess
+import sys
+
+def GenerateASanRuntimeStubs(asan_dylib, output_file):
+  symbols = _GetSymbolsToStub(asan_dylib)
+  _WriteStubsFile(symbols, output_file)
+
+
+def _GetSymbolsToStub(asan_dylib):
+  nm = ['xcrun', 'nm', '-j', '-g', '-U', asan_dylib]
+  output = subprocess.check_output(nm)
+  return output.strip().split('\n')
+
+
+def _WriteStubsFile(symbols_to_stub, output_file):
+  #symbols_to_stub = [s[1:] for s in symbols_to_stub]
+  resolvers = [_STUB_TEMPLATE % {'name': name} for name in symbols_to_stub]
+  initializers = [_INITIALIZER_TEMPLATE % {'name': name} for name in symbols_to_stub]
+  contents = _FILE_TEMPLATE % {'resolvers': ''.join(resolvers),
+                               'initializers': ''.join(initializers)}
+  with open(output_file, 'w') as f:
+    f.write(contents)
+
+
+def Main():
+  parser = optparse.OptionParser(
+      usage='%prog path/libclang_rt.asan_osx_dynamic.dylib path/gen/file.c')
+  opts, args = parser.parse_args()
+  if len(args) != 2:
+    parser.error('invalid arguments')
+
+  GenerateASanRuntimeStubs(*args)
+  return 0
+
+
+_FILE_TEMPLATE = """// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// NOTICE: This file is generated by:
+// build/config/sanitizers/generate_asan_runtime_stubs.py.
+
+#include <dlfcn.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+%(resolvers)s
+
+static bool did_initialize = []() {
+  printf("IN INITIALIZER RESOLVER\\n");
+  void* library = dlopen(getenv("CHROMIUM_ASAN"), RTLD_LAZY);
+  if (!library)
+    return false;
+
+  %(initializers)s
+  return true;
+}();
+
+"""
+
+_INITIALIZER_TEMPLATE = """
+  ptr_%(name)s = dlsym(library, "%(name)s");
+"""
+
+
+_STUB_TEMPLATE = """
+void* ptr_%(name)s = nullptr;
+
+__asm__(".globl %(name)s;"
+        "%(name)s:"
+        "movq _ptr_%(name)s(%%rip), %%rax;"
+        "jmpq *%%rax");
+"""
+
+
+if __name__ == '__main__':
+  sys.exit(Main())