Bug 930437 - Remove unnecessary compilation aborts from Lowering::visitToInt32. r=bhackett

js/src/jit/Lowering.cpp

@@ -1732,17 +1732,10 @@ LIRGenerator::visitToInt32(MToInt32 *convert)
       }
 
       case MIRType_String:
-        // Strings are complicated - we don't handle them yet.
-        IonSpew(IonSpew_Abort, "String to Int32 not supported yet.");
-        return false;
-
       case MIRType_Object:
-        // Objects might be effectful.
-        IonSpew(IonSpew_Abort, "Object to Int32 not supported yet.");
-        return false;
-
       case MIRType_Undefined:
-        IonSpew(IonSpew_Abort, "Undefined coerces to NaN, not int32_t.");
+        // Objects might be effectful. Undefined coerces to NaN, not int32.
+        MOZ_ASSUME_UNREACHABLE("ToInt32 invalid input type");
         return false;
 
       default:

js/src/jit/MIR.h

@@ -2919,7 +2919,9 @@ class MAsmJSUnsignedToFloat32
 // Converts a primitive (either typed or untyped) to an int32. If the input is
 // not primitive at runtime, a bailout occurs. If the input cannot be converted
 // to an int32 without loss (i.e. "5.5" or undefined) then a bailout occurs.
-class MToInt32 : public MUnaryInstruction
+class MToInt32
+  : public MUnaryInstruction,
+    public ToInt32Policy
 {
     bool canBeNegativeZero_;
 
@@ -2950,6 +2952,10 @@ class MToInt32 : public MUnaryInstruction
         canBeNegativeZero_ = negativeZero;
     }
 
+    TypePolicy *typePolicy() {
+        return this;
+    }
+
     bool congruentTo(MDefinition *ins) const {
         return congruentIfOperandsEqual(ins);
     }

js/src/jit/TypePolicy.cpp

@@ -536,6 +536,27 @@ ToDoublePolicy::staticAdjustInputs(MInstruction *ins)
     return true;
 }
 
+bool
+ToInt32Policy::staticAdjustInputs(MInstruction *ins)
+{
+    JS_ASSERT(ins->isToInt32());
+
+    MDefinition *in = ins->getOperand(0);
+    switch (in->type()) {
+      case MIRType_Object:
+      case MIRType_String:
+      case MIRType_Undefined:
+        // Objects might be effectful. Undefined coerces to NaN, not int32.
+        in = boxAt(ins, in);
+        ins->replaceOperand(0, in);
+        break;
+      default:
+        break;
+    }
+
+    return true;
+}
+
 template <unsigned Op>
 bool
 ObjectPolicy<Op>::staticAdjustInputs(MInstruction *ins)

js/src/jit/TypePolicy.h

@@ -194,6 +194,16 @@ class ToDoublePolicy : public BoxInputsPolicy
     }
 };
 
+// Box objects, strings and undefined as input to a ToInt32 instruction.
+class ToInt32Policy : public BoxInputsPolicy
+{
+  public:
+    static bool staticAdjustInputs(MInstruction *def);
+    bool adjustInputs(MInstruction *def) {
+        return staticAdjustInputs(def);
+    }
+};
+
 template <unsigned Op>
 class ObjectPolicy : public BoxInputsPolicy
 {