Bug 966957: Specialize ToString for Float32; r=h4writer

js/src/jit/CodeGenerator.cpp

@@ -776,6 +776,32 @@ CodeGenerator::visitDoubleToString(LDoubleToString *lir)
     return true;
 }
 
+typedef JSString *(*FloatToStringFn)(ThreadSafeContext *, float);
+typedef JSString *(*FloatToStringParFn)(ForkJoinContext *, float);
+static const VMFunctionsModal FloatToStringInfo = VMFunctionsModal(
+    FunctionInfo<FloatToStringFn>(FloatToString),
+    FunctionInfo<FloatToStringParFn>(FloatToStringPar));
+
+bool
+CodeGenerator::visitFloatToString(LFloatToString *lir)
+{
+    FloatRegister input = ToFloatRegister(lir->input());
+    Register temp = ToRegister(lir->tempInt());
+    Register output = ToRegister(lir->output());
+
+    OutOfLineCode *ool = oolCallVM(FloatToStringInfo, lir, (ArgList(), input),
+                                   StoreRegisterTo(output));
+    if (!ool)
+        return false;
+
+    // Try float to integer conversion and run integer to string code.
+    masm.convertFloat32ToInt32(input, temp, ool->entry(), /* negativeCheck = */ true);
+    emitIntToString(temp, output, ool->entry());
+
+    masm.bind(ool->rejoin());
+    return true;
+}
+
 typedef JSString *(*PrimitiveToStringFn)(JSContext *, HandleValue);
 typedef JSString *(*PrimitiveToStringParFn)(ForkJoinContext *, HandleValue);
 static const VMFunctionsModal PrimitiveToStringInfo = VMFunctionsModal(

js/src/jit/CodeGenerator.h

@@ -91,6 +91,7 @@ class CodeGenerator : public CodeGeneratorSpecific
     void emitIntToString(Register input, Register output, Label *ool);
     bool visitIntToString(LIntToString *lir);
     bool visitDoubleToString(LDoubleToString *lir);
+    bool visitFloatToString(LFloatToString *lir);
     bool visitPrimitiveToString(LPrimitiveToString *lir);
     bool visitInteger(LInteger *lir);
     bool visitRegExp(LRegExp *lir);

js/src/jit/LIR-Common.h

@@ -3146,6 +3146,25 @@ class LDoubleToString : public LInstructionHelper<1, 1, 1>
     }
 };
 
+// Convert a float32 hosted on one definition to a string with a function call.
+class LFloatToString : public LInstructionHelper<1, 1, 1>
+{
+  public:
+    LIR_HEADER(FloatToString)
+
+    LFloatToString(const LAllocation &input, const LDefinition &temp) {
+        setOperand(0, input);
+        setTemp(0, temp);
+    }
+
+    const LDefinition *tempInt() {
+        return getTemp(0);
+    }
+    const MToString *mir() {
+        return mir_->toToString();
+    }
+};
+
 // Convert a primitive to a string with a function call.
 class LPrimitiveToString : public LInstructionHelper<1, BOX_PIECES, 1>
 {

js/src/jit/LOpcodes.h

@@ -145,6 +145,7 @@
     _(BooleanToString)              \
     _(IntToString)                  \
     _(DoubleToString)               \
+    _(FloatToString)                \
     _(PrimitiveToString)            \
     _(Start)                        \
     _(OsrEntry)                     \

js/src/jit/Lowering.cpp

@@ -1862,6 +1862,14 @@ LIRGenerator::visitToString(MToString *ins)
         return assignSafepoint(lir, ins);
       }
 
+      case MIRType_Float32: {
+        LFloatToString *lir = new(alloc()) LFloatToString(useRegister(opd), temp());
+
+        if (!define(lir, ins))
+            return false;
+        return assignSafepoint(lir, ins);
+      }
+
       case MIRType_Int32: {
         LIntToString *lir = new(alloc()) LIntToString(useRegister(opd));
 

js/src/jit/MIR.h

@@ -3147,6 +3147,7 @@ class MToString : public MUnaryInstruction
         JS_ASSERT(!input()->mightBeType(MIRType_Object));
         return AliasSet::None();
     }
+    bool canConsumeFloat32() const { return true; }
 };
 
 class MBitNot

js/src/jit/ParallelFunctions.cpp

@@ -663,3 +663,9 @@ jit::InitRestParameterPar(ForkJoinContext *cx, uint32_t length, Value *rest,
 
     return res;
 }
+
+JSString *
+js::jit::FloatToStringPar(ForkJoinContext *cx, float f)
+{
+    return NumberToString<NoGC>(cx, double(f));
+}

js/src/jit/ParallelFunctions.h

@@ -78,6 +78,8 @@ void TraceLIR(IonLIRTraceData *current);
 
 void CallToUncompiledScriptPar(JSObject *obj);
 
+JSString *FloatToStringPar(ForkJoinContext *cx, float f);
+
 } // namespace jit
 } // namespace js
 

js/src/jit/TypePolicy.cpp

@@ -420,9 +420,6 @@ ConvertToStringPolicy<Op>::staticAdjustInputs(TempAllocator &alloc, MInstruction
 
         replace = MUnbox::New(alloc, in, MIRType_String, MUnbox::Fallible);
     } else {
-        // TODO remove these two lines once 966957 has landed
-        EnsureOperandNotFloat32(alloc, ins, Op);
-        in = ins->getOperand(Op);
         replace = MToString::New(alloc, in);
     }
 

js/src/jit/VMFunctions.cpp

@@ -970,6 +970,12 @@ StringReplace(JSContext *cx, HandleString string, HandleString pattern, HandleSt
     return rval.toString();
 }
 
+JSString *
+FloatToString(ThreadSafeContext *cx, float f)
+{
+    return NumberToString<CanGC>(cx, double(f));
+}
+
 bool
 Recompile(JSContext *cx)
 {

js/src/jit/VMFunctions.h

@@ -668,6 +668,8 @@ JSString *RegExpReplace(JSContext *cx, HandleString string, HandleObject regexp,
 JSString *StringReplace(JSContext *cx, HandleString string, HandleString pattern,
                         HandleString repl);
 
+JSString *FloatToString(ThreadSafeContext *cx, float f);
+
 #ifdef DEBUG
 void AssertValidObjectPtr(JSContext *cx, JSObject *obj);
 void AssertValidStringPtr(JSContext *cx, JSString *str);