Bug 1249736 - Remove redundant StartType from MStart. r=jandem

js/src/jit/BaselineBailouts.cpp

@@ -1895,7 +1895,6 @@ jit::FinishBailoutToBaseline(BaselineBailoutInfo* bailoutInfo)
       case Bailout_NonSimdInt32x4Input:
       case Bailout_NonSimdFloat32x4Input:
       case Bailout_NonSharedTypedArrayInput:
-      case Bailout_InitialState:
       case Bailout_Debugger:
       case Bailout_UninitializedThis:
       case Bailout_BadDerivedConstructorReturn:

js/src/jit/IonBuilder.cpp

@@ -845,7 +845,7 @@ IonBuilder::build()
     }
 
     // Emit the start instruction, so we can begin real instructions.
-    current->add(MStart::New(alloc(), MStart::StartType_Default));
+    current->add(MStart::New(alloc()));
 
     // Guard against over-recursion. Do this before we start unboxing, since
     // this will create an OSI point that will read the incoming argument
@@ -7584,7 +7584,7 @@ IonBuilder::newOsrPreheader(MBasicBlock* predecessor, jsbytecode* loopEntry, jsb
     }
 
     // Create an MStart to hold the first valid MResumePoint.
-    MStart* start = MStart::New(alloc(), MStart::StartType_Osr);
+    MStart* start = MStart::New(alloc());
     osrBlock->add(start);
 
     // MOsrValue instructions are infallible, so the first MResumePoint must

js/src/jit/IonTypes.h

@@ -110,9 +110,6 @@ enum BailoutKind
     // maps unshared memory.
     Bailout_NonSharedTypedArrayInput,
 
-    // For the initial snapshot when entering a function.
-    Bailout_InitialState,
-
     // We hit a |debugger;| statement.
     Bailout_Debugger,
 
@@ -222,8 +219,6 @@ BailoutKindString(BailoutKind kind)
         return "Bailout_NonSimdFloat32x4Input";
       case Bailout_NonSharedTypedArrayInput:
         return "Bailout_NonSharedTypedArrayInput";
-      case Bailout_InitialState:
-        return "Bailout_InitialState";
       case Bailout_Debugger:
         return "Bailout_Debugger";
       case Bailout_UninitializedThis:

js/src/jit/LIR.h

@@ -1312,9 +1312,6 @@ class LSnapshot : public TempObject
     BailoutKind bailoutKind() const {
         return bailoutKind_;
     }
-    void setBailoutKind(BailoutKind kind) {
-        bailoutKind_ = kind;
-    }
     void rewriteRecoveredInput(LUse input);
 };
 
@@ -1833,8 +1830,6 @@ class LIRGraph
     }
     void setEntrySnapshot(LSnapshot* snapshot) {
         MOZ_ASSERT(!entrySnapshot_);
-        MOZ_ASSERT(snapshot->bailoutKind() == Bailout_InitialState);
-        snapshot->setBailoutKind(Bailout_ArgumentCheck);
         entrySnapshot_ = snapshot;
     }
     LSnapshot* entrySnapshot() const {

js/src/jit/Lowering.cpp

@@ -1747,12 +1747,13 @@ LIRGenerator::visitFromCharCode(MFromCharCode* ins)
 void
 LIRGenerator::visitStart(MStart* start)
 {
-    // Create a snapshot that captures the initial state of the function.
     LStart* lir = new(alloc()) LStart;
-    assignSnapshot(lir, Bailout_InitialState);
 
-    if (start->startType() == MStart::StartType_Default && lir->snapshot())
+    // Create a snapshot that captures the initial state of the function.
+    assignSnapshot(lir, Bailout_ArgumentCheck);
+    if (start->block()->graph().entryBlock() == start->block())
         lirGraph_.setEntrySnapshot(lir->snapshot());
+
     add(lir);
 }
 

js/src/jit/MIR.h

@@ -1259,28 +1259,10 @@ typedef MVariadicT<MInstruction> MVariadicInstruction;
 // Generates an LSnapshot without further effect.
 class MStart : public MNullaryInstruction
 {
-  public:
-    enum StartType {
-        StartType_Default,
-        StartType_Osr
-    };
-
-  private:
-    StartType startType_;
-
-  private:
-    explicit MStart(StartType startType)
-      : startType_(startType)
-    { }
-
   public:
     INSTRUCTION_HEADER(Start)
-    static MStart* New(TempAllocator& alloc, StartType startType) {
-        return new(alloc) MStart(startType);
-    }
-
-    StartType startType() {
-        return startType_;
+    static MStart* New(TempAllocator& alloc) {
+        return new(alloc) MStart();
     }
 };
 

js/src/jit/MIRGraph.cpp

@@ -603,8 +603,6 @@ MBasicBlock::shimmySlots(int discardDepth)
 bool
 MBasicBlock::linkOsrValues(MStart* start)
 {
-    MOZ_ASSERT(start->startType() == MStart::StartType_Osr);
-
     MResumePoint* res = start->resumePoint();
 
     for (uint32_t i = 0; i < stackDepth(); i++) {