android: Realign stack pointer on JNI entry.

base/android/jni_generator/jni_generator.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """Extracts native methods from a Java file and generates the JNI bindings.
 If you change this, please run and update the tests."""
 
 import collections
 import errno
@@ skipping 1012 matching lines @@
 
     if is_method:
       optional_error_return = JavaReturnValueToC(native.return_type)
       if optional_error_return:
         optional_error_return = ', ' + optional_error_return
       values.update({
           'OPTIONAL_ERROR_RETURN': optional_error_return,
           'PARAM0_NAME': native.params[0].name,
           'P0_TYPE': native.p0_type,
       })
+      # Dalvik JIT generated code doesn't guarantee 16-byte stack alignment on
+      # x86 - use force_align_arg_pointer to realign the stack at the JNI
+      # boundary. crbug.com/655248
       template = Template("""\
 extern "C" __attribute__((visibility("default")))
+#if defined(ARCH_CPU_X86)
+__attribute__((force_align_arg_pointer))
+#endif
 ${RETURN} ${STUB_NAME}(JNIEnv* env,
     ${PARAMS_IN_STUB}) {
   ${PROFILING_ENTERED_NATIVE}
   ${P0_TYPE}* native = reinterpret_cast<${P0_TYPE}*>(${PARAM0_NAME});
   CHECK_NATIVE_PTR(env, jcaller, native, "${NAME}"${OPTIONAL_ERROR_RETURN});
   return native->${NAME}(${PARAMS_IN_CALL})${POST_CALL};
 }
 """)
     else:
       template = Template("""
 static ${RETURN_DECLARATION} ${NAME}(JNIEnv* env, ${PARAMS});
 
 extern "C" __attribute__((visibility("default")))
+#if defined(ARCH_CPU_X86)
+__attribute__((force_align_arg_pointer))
+#endif
 ${RETURN} ${STUB_NAME}(JNIEnv* env, ${PARAMS_IN_STUB}) {
   ${PROFILING_ENTERED_NATIVE}
   return ${NAME}(${PARAMS_IN_CALL})${POST_CALL};
 }
 """)
 
     return RemoveIndentedEmptyLines(template.substitute(values))
 
   def GetArgument(self, param):
     if param.datatype == 'int':
@@ skipping 338 matching lines @@
     root_name = os.path.splitext(os.path.basename(input_file))[0]
     output_file = os.path.join(options.output_dir, root_name) + '_jni.h'
   GenerateJNIHeader(input_file, output_file, options)
 
   if options.depfile:
     build_utils.WriteDepfile(options.depfile, output_file)
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))