// PTAL, repro:
function foo() {
  "use asm";
  function bar(x) {
    x = x|0;
  }
  return { bar: bar };
}
var v = foo();
v.__defineGetter__("bar", function() { return 0; });
v.bar()

// Output:
# Compared x64,ignition with x64,ignition_asm
#
# Flags of x64,ignition:
--abort_on_stack_overflow --expose-gc --allow-natives-syntax --invoke-weak-callbacks --omit-quit --es-staging --random-seed 732681078 --ignition --turbo-filter=~ --hydrogen-filter=~ --nocrankshaft
# Flags of x64,ignition_asm:
--abort_on_stack_overflow --expose-gc --allow-natives-syntax --invoke-weak-callbacks --omit-quit --es-staging --random-seed 732681078 --ignition --turbo-filter=~ --hydrogen-filter=~ --nocrankshaft --validate-asm --fast-validate-asm --stress-validate-asm --suppress-asm-messages
#
# Difference:
- ./repro.js:11: TypeError: v.bar is not a function
#
# Source file:
none
#
### Start of configuration x64,ignition:
./repro.js:11: TypeError: v.bar is not a function
v.bar()
  ^



### End of configuration x64,ignition
#
### Start of configuration x64,ignition_asm:

### End of configuration x64,ignition_asm

Huh, this is exactly the same as  issue 683086 . :/

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/d049239ca64eb2f278adc48740d12cb687c77575

commit d049239ca64eb2f278adc48740d12cb687c77575
Author: Michael Starzinger <mstarzinger@chromium.org>
Date: Tue Apr 25 14:19:52 2017

[asm.js] Fix [[Configurable]] attribute of exports.

R=clemensh@chromium.org
TEST=mjsunit/asm/asm-validation
BUG= chromium:715068 , v8:5877 

Change-Id: I26e0b84c94e5f036336f39e9d764f0588ff3ec0d
Reviewed-on: https://chromium-review.googlesource.com/486882
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44861}
[modify] https://crrev.com/d049239ca64eb2f278adc48740d12cb687c77575/src/wasm/wasm-module.cc
[modify] https://crrev.com/d049239ca64eb2f278adc48740d12cb687c77575/test/mjsunit/asm/asm-validation.js

ClusterFuzz has detected this issue as fixed in range 44860:44861.

Detailed report: https://clusterfuzz.com/testcase?key=5043095969464320

Fuzzer: foozzie_js_mutation
Job Type: v8_foozzie
Platform Id: linux

Crash Type: V8 correctness failure
Crash Address: 
Crash State:
  configs: x64,ignition:x64,ignition_asm
  sources: 6fb
  
Sanitizer: address (ASAN)

Regressed: V8: 44685:44686
Fixed: V8: 44860:44861

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5043095969464320


See https://dev.chromium.org/Home/chromium-security/bugs/reproducing-clusterfuzz-bugs for more information.

If you suspect that the result above is incorrect, try re-doing that job on the test case report page.