[ignition/turbofan] Use Switch node for Switch bytecode

Uses CheckSmi to force the switch argument to be a Smi, so that it can
be used as an input into a Switch node.

Change-Id: Ibec6beaeebc2168a3f80b86512c70a99d52f2575
Reviewed-on: https://chromium-review.googlesource.com/505621
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45397}

src/compiler/bytecode-graph-builder.cc

@@ -2165,24 +2165,25 @@ void BytecodeGraphBuilder::VisitJumpIfNotUndefinedConstant() {
 
 void BytecodeGraphBuilder::VisitJumpLoop() { BuildJump(); }
 
-void BytecodeGraphBuilder::VisitSwitchOnSmiNoFeedback() {
-  PrepareEagerCheckpoint();
-
-  Node* acc = environment()->LookupAccumulator();
+void BytecodeGraphBuilder::BuildSwitchOnSmi(Node* condition) {
+  interpreter::JumpTableTargetOffsets offsets =
+      bytecode_iterator().GetJumpTableTargetOffsets();
 
-  for (const auto& entry : bytecode_iterator().GetJumpTableTargetOffsets()) {
-    // TODO(leszeks): This should be a switch, but under OSR we fail to type the
-    // input correctly so we have to do a JS strict equal instead.
-    NewBranch(
-        NewNode(javascript()->StrictEqual(CompareOperationHint::kSignedSmall),
-                acc, jsgraph()->SmiConstant(entry.case_value)));
-    {
+  NewSwitch(condition, offsets.size() + 1);
+  for (const auto& entry : offsets) {
     SubEnvironment sub_environment(this);
-      NewIfTrue();
+    NewIfValue(entry.case_value);
     MergeIntoSuccessorEnvironment(entry.target_offset);
   }
-    NewIfFalse();
-  }
+  NewIfDefault();
+}
+
+void BytecodeGraphBuilder::VisitSwitchOnSmiNoFeedback() {
+  PrepareEagerCheckpoint();
+
+  Node* acc = environment()->LookupAccumulator();
+  Node* acc_smi = NewNode(simplified()->CheckSmi(), acc);
+  BuildSwitchOnSmi(acc_smi);
 }
 
 void BytecodeGraphBuilder::VisitStackCheck() {

src/compiler/bytecode-graph-builder.h

@@ -91,11 +91,16 @@ class BytecodeGraphBuilder {
   // Helpers to create new control nodes.
   Node* NewIfTrue() { return NewNode(common()->IfTrue()); }
   Node* NewIfFalse() { return NewNode(common()->IfFalse()); }
+  Node* NewIfValue(int32_t value) { return NewNode(common()->IfValue(value)); }
+  Node* NewIfDefault() { return NewNode(common()->IfDefault()); }
   Node* NewMerge() { return NewNode(common()->Merge(1), true); }
   Node* NewLoop() { return NewNode(common()->Loop(1), true); }
   Node* NewBranch(Node* condition, BranchHint hint = BranchHint::kNone) {
     return NewNode(common()->Branch(hint), condition);
   }
+  Node* NewSwitch(Node* condition, int control_output_count) {
+    return NewNode(common()->Switch(control_output_count), condition);
+  }
 
   // Creates a new Phi node having {count} input values.
   Node* NewPhi(int count, Node* input, Node* control);
@@ -222,6 +227,8 @@ class BytecodeGraphBuilder {
   void BuildJumpIfNotHole();
   void BuildJumpIfJSReceiver();
 
+  void BuildSwitchOnSmi(Node* condition);
+
   // Simulates control flow by forward-propagating environments.
   void MergeIntoSuccessorEnvironment(int target_offset);
   void BuildLoopHeaderEnvironment(int current_offset);

src/interpreter/bytecode-array-accessor.cc

@@ -237,6 +237,15 @@ JumpTableTargetOffsets::iterator JumpTableTargetOffsets::end() const {
   return iterator(case_value_base_ + table_size_, table_start_ + table_size_,
                   table_start_ + table_size_, accessor_);
 }
+int JumpTableTargetOffsets::size() const {
+  int ret = 0;
+  // TODO(leszeks): Is there a more efficient way of doing this than iterating?
+  for (const auto& entry : *this) {
+    USE(entry);
+    ret++;
+  }
+  return ret;
+}
 
 JumpTableTargetOffsets::iterator::iterator(
     int case_value, int table_offset, int table_end,

src/interpreter/bytecode-array-accessor.h

@@ -51,6 +51,8 @@ class V8_EXPORT_PRIVATE JumpTableTargetOffsets final {
   iterator begin() const;
   iterator end() const;
 
+  int size() const;
+
  private:
   const BytecodeArrayAccessor* accessor_;
   int table_start_;