Add Isolate parameter to disallow Atomics.wait

Atomics.wait is a function which may block, which is not allowed on the
main thread. Since V8 doesn't know whether a particular isolate is the
"main thread", this CL adds an option to Isolate::CreateParams to choose
whether this function is allowed.

Review-Url: https://codereview.chromium.org/2642293002
Cr-Commit-Position: refs/heads/master@{#42611}

include/v8.h

@@ -6345,7 +6345,8 @@ class V8_EXPORT Isolate {
           create_histogram_callback(nullptr),
           add_histogram_sample_callback(nullptr),
           array_buffer_allocator(nullptr),
-          external_references(nullptr) {}
+          external_references(nullptr),
+          allow_atomics_wait(true) {}
 
     /**
      * The optional entry_hook allows the host application to provide the
@@ -6401,6 +6402,12 @@ class V8_EXPORT Isolate {
      * entire lifetime of the isolate.
      */
     intptr_t* external_references;
+
+    /**
+     * Whether calling Atomics.wait (a function that may block) is allowed in
+     * this isolate.
+     */
+    bool allow_atomics_wait;
   };
 
 

src/api.cc

@@ -8121,6 +8121,7 @@ Isolate* Isolate::New(const Isolate::CreateParams& params) {
   }
 
   isolate->set_api_external_references(params.external_references);
+  isolate->set_allow_atomics_wait(params.allow_atomics_wait);
   SetResourceConstraints(isolate, params.constraints);
   // TODO(jochen): Once we got rid of Isolate::Current(), we can remove this.
   Isolate::Scope isolate_scope(v8_isolate);

src/isolate.h

@@ -1194,6 +1194,9 @@ class Isolate {
   base::Mutex* simulator_i_cache_mutex() { return &simulator_i_cache_mutex_; }
 #endif
 
+  void set_allow_atomics_wait(bool set) { allow_atomics_wait_ = set; }
+  bool allow_atomics_wait() { return allow_atomics_wait_; }
+
  protected:
   explicit Isolate(bool enable_serializer);
   bool IsArrayOrObjectPrototype(Object* object);
@@ -1472,6 +1475,8 @@ class Isolate {
   base::Mutex simulator_i_cache_mutex_;
 #endif
 
+  bool allow_atomics_wait_;
+
   friend class ExecutionAccess;
   friend class HandleScopeImplementer;
   friend class HeapTester;

src/messages.h

@@ -269,6 +269,7 @@ class ErrorUtils : public AllStatic {
     "ArrayBuffer subclass returned this from species constructor")             \
   T(ArrayFunctionsOnFrozen, "Cannot modify frozen array elements")             \
   T(ArrayFunctionsOnSealed, "Cannot add/remove sealed array elements")         \
+  T(AtomicsWaitNotAllowed, "Atomics.wait cannot be called in this context")    \
   T(CalledNonCallable, "% is not a function")                                  \
   T(CalledOnNonObject, "% called on non-object")                               \
   T(CalledOnNullOrUndefined, "% called on null or undefined")                  \

src/runtime/runtime-futex.cc

@@ -29,6 +29,11 @@ RUNTIME_FUNCTION(Runtime_AtomicsWait) {
   CHECK_EQ(sta->type(), kExternalInt32Array);
   CHECK(timeout == V8_INFINITY || !std::isnan(timeout));
 
+  if (!isolate->allow_atomics_wait()) {
+    THROW_NEW_ERROR_RETURN_FAILURE(
+        isolate, NewTypeError(MessageTemplate::kAtomicsWaitNotAllowed));
+  }
+
   Handle<JSArrayBuffer> array_buffer = sta->GetBuffer();
   size_t addr = (index << 2) + NumberToSize(sta->byte_offset());
 
@@ -65,5 +70,14 @@ RUNTIME_FUNCTION(Runtime_AtomicsNumWaitersForTesting) {
 
   return FutexEmulation::NumWaitersForTesting(isolate, array_buffer, addr);
 }
+
+RUNTIME_FUNCTION(Runtime_SetAllowAtomicsWait) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(1, args.length());
+  CONVERT_BOOLEAN_ARG_CHECKED(set, 0);
+
+  isolate->set_allow_atomics_wait(set);
+  return isolate->heap()->undefined_value();
+}
 }  // namespace internal
 }  // namespace v8

src/runtime/runtime.h

@@ -73,7 +73,8 @@ namespace internal {
   F(AtomicsIsLockFree, 1, 1)                    \
   F(AtomicsWait, 4, 1)                          \
   F(AtomicsWake, 3, 1)                          \
-  F(AtomicsNumWaitersForTesting, 2, 1)
+  F(AtomicsNumWaitersForTesting, 2, 1)          \
+  F(SetAllowAtomicsWait, 1, 1)
 
 #define FOR_EACH_INTRINSIC_CLASSES(F)        \
   F(ThrowUnsupportedSuperError, 0, 1)        \

test/cctest/interpreter/bytecode_expectations/ForOf.golden

@@ -88,7 +88,7 @@ bytecodes: [
                 B(TestEqualStrict), R(12), U8(20),
                 B(JumpIfFalse), U8(4),
                 B(Jump), U8(18),
-                B(Wide), B(LdaSmi), U16(129),
+                B(Wide), B(LdaSmi), U16(130),
                 B(Star), R(12),
                 B(LdaConstant), U8(9),
                 B(Star), R(13),
@@ -233,7 +233,7 @@ bytecodes: [
                 B(TestEqualStrict), R(13), U8(20),
                 B(JumpIfFalse), U8(4),
                 B(Jump), U8(18),
-                B(Wide), B(LdaSmi), U16(129),
+                B(Wide), B(LdaSmi), U16(130),
                 B(Star), R(13),
                 B(LdaConstant), U8(9),
                 B(Star), R(14),
@@ -391,7 +391,7 @@ bytecodes: [
                 B(TestEqualStrict), R(12), U8(22),
                 B(JumpIfFalse), U8(4),
                 B(Jump), U8(18),
-                B(Wide), B(LdaSmi), U16(129),
+                B(Wide), B(LdaSmi), U16(130),
                 B(Star), R(12),
                 B(LdaConstant), U8(9),
                 B(Star), R(13),
@@ -539,7 +539,7 @@ bytecodes: [
                 B(TestEqualStrict), R(11), U8(24),
                 B(JumpIfFalse), U8(4),
                 B(Jump), U8(18),
-                B(Wide), B(LdaSmi), U16(129),
+                B(Wide), B(LdaSmi), U16(130),
                 B(Star), R(11),
                 B(LdaConstant), U8(11),
                 B(Star), R(12),

test/cctest/interpreter/bytecode_expectations/Generators.golden

@@ -497,7 +497,7 @@ bytecodes: [
                 B(TestEqualStrict), R(11), U8(20),
                 B(JumpIfFalse), U8(4),
                 B(Jump), U8(18),
-                B(Wide), B(LdaSmi), U16(129),
+                B(Wide), B(LdaSmi), U16(130),
                 B(Star), R(11),
                 B(LdaConstant), U8(14),
                 B(Star), R(12),

test/mjsunit/harmony/futex.js

@@ -95,6 +95,15 @@
   assertEquals("timed-out", Atomics.wait(i32a, 0, 0, -Infinity));
 })();
 
+(function TestWaitNotAllowed() {
+  %SetAllowAtomicsWait(false);
+  var i32a = new Int32Array(new SharedArrayBuffer(16));
+  assertThrows(function() {
+    Atomics.wait(i32a, 0, 0, -1);
+  });
+  %SetAllowAtomicsWait(true);
+})();
+
 //// WORKER ONLY TESTS
 
 if (this.Worker) {