deps: patch V8 to 9.0.257.21

Refs: v8/v8@9.0.257.19...9.0.257.21 PR-URL: #38333 Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Jiawen Geng <[email protected]> Reviewed-By: Richard Lau <[email protected]> Reviewed-By: James M Snell <[email protected]>

Author: targos

deps/v8/include/v8-version.h

@@ -11,7 +11,7 @@
 #defineV8_MAJOR_VERSION 9
 #defineV8_MINOR_VERSION 0
 #defineV8_BUILD_NUMBER 257
-#defineV8_PATCH_LEVEL19
+#defineV8_PATCH_LEVEL21
 
 // Use 1 for candidates and 0 otherwise.
 // (Boolean macro values are not supported by all preprocessors.)

deps/v8/src/compiler/js-call-reducer.cc

@@ -5380,24 +5380,31 @@ Reduction JSCallReducer::ReduceArrayPrototypePop(Node* node){
  }
 
 // Compute the new{length}.
- length = graph()->NewNode(simplified()->NumberSubtract(), length,
-jsgraph()->OneConstant());
+ Node* new_length = graph()->NewNode(simplified()->NumberSubtract(),
+ length, jsgraph()->OneConstant());
+
+// This extra check exists solely to break an exploitation technique
+// that abuses typer mismatches.
+ new_length = efalse = graph()->NewNode(
+simplified()->CheckBounds(p.feedback(),
+ CheckBoundsFlag::kAbortOnOutOfBounds),
+ new_length, length, efalse, if_false);
 
 // Store the new{length} to the{receiver}.
  efalse = graph()->NewNode(
 simplified()->StoreField(AccessBuilder::ForJSArrayLength(kind)),
- receiver, length, efalse, if_false);
+ receiver, new_length, efalse, if_false);
 
 // Load the last entry from the{elements}.
  vfalse = efalse = graph()->NewNode(
 simplified()->LoadElement(AccessBuilder::ForFixedArrayElement(kind)),
- elements, length, efalse, if_false);
+ elements, new_length, efalse, if_false);
 
 // Store a hole to the element we just removed from the{receiver}.
  efalse = graph()->NewNode(
 simplified()->StoreElement(
 AccessBuilder::ForFixedArrayElement(GetHoleyElementsKind(kind))),
- elements, length, jsgraph()->TheHoleConstant(), efalse, if_false);
+ elements, new_length, jsgraph()->TheHoleConstant(), efalse, if_false);
  }
 
  control = graph()->NewNode(common()->Merge(2), if_true, if_false);
@@ -5573,19 +5580,27 @@ Reduction JSCallReducer::ReduceArrayPrototypeShift(Node* node){
  }
 
 // Compute the new{length}.
- length = graph()->NewNode(simplified()->NumberSubtract(), length,
-jsgraph()->OneConstant());
+ Node* new_length = graph()->NewNode(simplified()->NumberSubtract(),
+ length, jsgraph()->OneConstant());
+
+// This extra check exists solely to break an exploitation technique
+// that abuses typer mismatches.
+ new_length = etrue1 = graph()->NewNode(
+simplified()->CheckBounds(p.feedback(),
+ CheckBoundsFlag::kAbortOnOutOfBounds),
+ new_length, length, etrue1, if_true1);
 
 // Store the new{length} to the{receiver}.
  etrue1 = graph()->NewNode(
 simplified()->StoreField(AccessBuilder::ForJSArrayLength(kind)),
- receiver, length, etrue1, if_true1);
+ receiver, new_length, etrue1, if_true1);
 
 // Store a hole to the element we just removed from the{receiver}.
  etrue1 = graph()->NewNode(
 simplified()->StoreElement(AccessBuilder::ForFixedArrayElement(
 GetHoleyElementsKind(kind))),
- elements, length, jsgraph()->TheHoleConstant(), etrue1, if_true1);
+ elements, new_length, jsgraph()->TheHoleConstant(), etrue1,
+ if_true1);
  }
 
  Node* if_false1 = graph()->NewNode(common()->IfFalse(), branch1);

deps/v8/src/compiler/simplified-lowering.cc

@@ -1474,10 +1474,15 @@ class RepresentationSelector{
  Type right_feedback_type = TypeOf(node->InputAt(1));
 
 // Using Signed32 as restriction type amounts to promising there won't be
-// signed overflow. This is incompatible with relying on a Word32
-// truncation in order to skip the overflow check.
+// signed overflow. This is incompatible with relying on a Word32 truncation
+// in order to skip the overflow check. Similarly, we must not drop -0 from
+// the result type unless we deopt for -0 inputs.
  Type const restriction =
- truncation.IsUsedAsWord32() ? Type::Any() : Type::Signed32();
+ truncation.IsUsedAsWord32()
+ ? Type::Any()
+ : (truncation.identify_zeros() == kIdentifyZeros)
+ ? Type::Signed32OrMinusZero()
+ : Type::Signed32();
 
 // Handle the case when no int32 checks on inputs are necessary (but
 // an overflow check is needed on the output). Note that we do not