[Backport] CVE-2021-30513: Type Confusion in V8

Cherry-pick of commit originally reviewed on
https://chromium-review.googlesource.com/c/v8/v8/+/2883780:
Reland "[compiler] Fix more truncation bugs in SimplifiedLowering"

This is a reland of 47077d94492cb604e3a7f02c0d7c3c495ff6b713 without
changes. The revert was false alarm.

[M86]: Resolved simple conflicts.

Original change's description:
> [compiler] Fix more truncation bugs in SimplifiedLowering
>
> Bug: chromium:1200490
> Change-Id: I3555b6d99bdb4b4e7c302a43a82c17e8bff84ebe
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2840452
> Reviewed-by: Nico Hartmann <[email protected]>
> Commit-Queue: Georg Neis <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#74097}

(cherry picked from commit e4a580c9104e42968e8e13b8c7d933f0b2eda2a3)

(cherry picked from commit 97ad04543438f7b235b21346fdd198f81028cd5e)

Bug: chromium:1200490
Tbr: [email protected]
No-Try: true
No-Presubmit: true
No-Tree-Checks: true
Change-Id: Iedddcf2d0117fa59dc9d7a3604ef203808ad2903
Reviewed-by: Georg Neis <[email protected]>
Commit-Queue: Georg Neis <[email protected]>
Cr-Original-Commit-Position: refs/branch-heads/9.0@{#47}
Cr-Original-Branched-From: bd0108b4c88e0d6f2350cb79b5f363fbd02f3eb7-refs/heads/9.0.257@{#1}
Cr-Original-Branched-From: 349bcc6a075411f1a7ce2d866c3dfeefc2efa39d-refs/heads/master@{#73001}
Reviewed-by: Jana Grill <[email protected]>
Commit-Queue: Victor-Gabriel Savu <[email protected]>
Cr-Commit-Position: refs/branch-heads/8.6@{#95}
Cr-Branched-From: a64aed2333abf49e494d2a5ce24bbd14fff19f60-refs/heads/8.6.395@{#1}
Cr-Branched-From: a626bc036236c9bf92ac7b87dc40c9e538b087e3-refs/heads/master@{#69472}
Reviewed-by: Allan Sandfeld Jensen <[email protected]>

Author: GeorgNeis

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

@@ -1398,17 +1398,32 @@ class RepresentationSelector {
     return jsgraph_->simplified();
   }
 
-  void LowerToCheckedInt32Mul(Node* node, Truncation truncation,
-                              Type input0_type, Type input1_type) {
-    // If one of the inputs is positive and/or truncation is being applied,
-    // there is no need to return -0.
-    CheckForMinusZeroMode mz_mode =
-        truncation.IdentifiesZeroAndMinusZero() ||
-                IsSomePositiveOrderedNumber(input0_type) ||
-                IsSomePositiveOrderedNumber(input1_type)
-            ? CheckForMinusZeroMode::kDontCheckForMinusZero
-            : CheckForMinusZeroMode::kCheckForMinusZero;
-    NodeProperties::ChangeOp(node, simplified()->CheckedInt32Mul(mz_mode));
+  template <Phase T>
+  void VisitForCheckedInt32Mul(Node* node, Truncation truncation,
+                               Type input0_type, Type input1_type,
+                               UseInfo input_use) {
+    DCHECK_EQ(node->opcode(), IrOpcode::kSpeculativeNumberMultiply);
+    // A -0 input is impossible or will cause a deopt.
+    DCHECK(BothInputsAre(node, Type::Signed32()) ||
+           !input_use.truncation().IdentifiesZeroAndMinusZero());
+
+    CheckForMinusZeroMode mz_mode;
+    Type restriction;
+    if (IsSomePositiveOrderedNumber(input0_type) ||
+        IsSomePositiveOrderedNumber(input1_type)) {
+      mz_mode = CheckForMinusZeroMode::kDontCheckForMinusZero;
+      restriction = Type::Signed32();
+    } else if (truncation.IdentifiesZeroAndMinusZero()) {
+      mz_mode = CheckForMinusZeroMode::kDontCheckForMinusZero;
+      restriction = Type::Signed32OrMinusZero();
+    } else {
+      mz_mode = CheckForMinusZeroMode::kCheckForMinusZero;
+      restriction = Type::Signed32();
+    }
+
+    VisitBinop<T>(node, input_use, MachineRepresentation::kWord32, restriction);
+    if (lower<T>())
+      NodeProperties::ChangeOp(node, simplified()->CheckedInt32Mul(mz_mode));
   }
 
   void ChangeToInt32OverflowOp(Node* node) {
@@ -1600,12 +1615,22 @@ class RepresentationSelector {
         VisitBinop<T>(node, lhs_use, rhs_use, MachineRepresentation::kWord32);
         if (lower<T>()) DeferReplacement(node, lowering->Int32Mod(node));
       } else if (BothInputsAre(node, Type::Unsigned32OrMinusZeroOrNaN())) {
+        Type const restriction =
+            truncation.IdentifiesZeroAndMinusZero() &&
+                    TypeOf(node->InputAt(0)).Maybe(Type::MinusZero())
+                ? Type::Unsigned32OrMinusZero()
+                : Type::Unsigned32();
         VisitBinop<T>(node, lhs_use, rhs_use, MachineRepresentation::kWord32,
-                      Type::Unsigned32());
+                      restriction);
         if (lower<T>()) ChangeToUint32OverflowOp(node);
       } else {
+        Type const restriction =
+            truncation.IdentifiesZeroAndMinusZero() &&
+                    TypeOf(node->InputAt(0)).Maybe(Type::MinusZero())
+                ? Type::Signed32OrMinusZero()
+                : Type::Signed32();
         VisitBinop<T>(node, lhs_use, rhs_use, MachineRepresentation::kWord32,
-                      Type::Signed32());
+                      restriction);
         if (lower<T>()) ChangeToInt32OverflowOp(node);
       }
       return;
@@ -2165,23 +2190,17 @@ class RepresentationSelector {
           // If both inputs and feedback are int32, use the overflow op.
           if (hint == NumberOperationHint::kSignedSmall ||
               hint == NumberOperationHint::kSigned32) {
-            VisitBinop<T>(node, UseInfo::TruncatingWord32(),
-                          MachineRepresentation::kWord32, Type::Signed32());
-            if (lower<T>()) {
-              LowerToCheckedInt32Mul(node, truncation, input0_type,
-                                     input1_type);
-            }
+            VisitForCheckedInt32Mul<T>(node, truncation, input0_type,
+                                       input1_type,
+                                       UseInfo::TruncatingWord32());
             return;
           }
         }
 
         if (hint == NumberOperationHint::kSignedSmall ||
             hint == NumberOperationHint::kSigned32) {
-          VisitBinop<T>(node, CheckedUseInfoAsWord32FromHint(hint),
-                        MachineRepresentation::kWord32, Type::Signed32());
-          if (lower<T>()) {
-            LowerToCheckedInt32Mul(node, truncation, input0_type, input1_type);
-          }
+          VisitForCheckedInt32Mul<T>(node, truncation, input0_type, input1_type,
+                                     CheckedUseInfoAsWord32FromHint(hint));
           return;
         }
 
@@ -3901,7 +3920,6 @@ template <>
 void RepresentationSelector::SetOutput<RETYPE>(
     Node* node, MachineRepresentation representation, Type restriction_type) {
   NodeInfo* const info = GetInfo(node);
-  DCHECK(info->restriction_type().Is(restriction_type));
   DCHECK(restriction_type.Is(info->restriction_type()));
   info->set_output(representation);
 }
@@ -3911,7 +3929,6 @@ void RepresentationSelector::SetOutput<LOWER>(
     Node* node, MachineRepresentation representation, Type restriction_type) {
   NodeInfo* const info = GetInfo(node);
   DCHECK_EQ(info->representation(), representation);
-  DCHECK(info->restriction_type().Is(restriction_type));
   DCHECK(restriction_type.Is(info->restriction_type()));
   USE(info);
 }