Port r10939 to x64 and arm (inline Math.random in crankshaft).

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index fcbc90da5f8ed39fe30dee540a5c0e08542579a5..2a707a83fab6b851a1b80400a143fcf7f9d0e5fa 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -3230,15 +3230,62 @@ void LCodeGen::DoPower(LPower* instr) {
 
 
 void LCodeGen::DoRandom(LRandom* instr) {
+  class DeferredDoRandom: public LDeferredCode {
+   public:
+    DeferredDoRandom(LCodeGen* codegen, LRandom* instr)
+        : LDeferredCode(codegen), instr_(instr) { }
+    virtual void Generate() { codegen()->DoDeferredRandom(instr_); }
+    virtual LInstruction* instr() { return instr_; }
+   private:
+    LRandom* instr_;
+  };
+
+  DeferredDoRandom* deferred = new DeferredDoRandom(this, instr);
+
   // Having marked this instruction as a call we can use any
   // registers.
   ASSERT(ToDoubleRegister(instr->result()).is(d7));
   ASSERT(ToRegister(instr->InputAt(0)).is(r0));
 
-  __ PrepareCallCFunction(1, scratch0());
+  static const int kSeedSize = sizeof(uint32_t);
+  STATIC_ASSERT(kPointerSize == kSeedSize);
+
   __ ldr(r0, FieldMemOperand(r0, GlobalObject::kGlobalContextOffset));
-  __ CallCFunction(ExternalReference::random_uint32_function(isolate()), 1);
+  static const int kRandomSeedOffset =
+      FixedArray::kHeaderSize + Context::RANDOM_SEED_INDEX * kPointerSize;
+  __ ldr(r2, FieldMemOperand(r0, kRandomSeedOffset));
+  // r2: FixedArray of the global context's random seeds
+
+  // Load state[0].
+  __ ldr(r1, FieldMemOperand(r2, ByteArray::kHeaderSize));
+  __ cmp(r1, Operand(0));
+  __ b(eq, deferred->entry());
+  // Load state[1].
+  __ ldr(r0, FieldMemOperand(r2, ByteArray::kHeaderSize + kSeedSize));
+  // r1: state[0].
+  // r0: state[1].
+
+  // state[0] = 18273 * (state[0] & 0xFFFF) + (state[0] >> 16)
+  __ and_(r3, r1, Operand(0xFFFF));
+  __ mov(r4, Operand(18273));
+  __ mul(r3, r3, r4);
+  __ add(r1, r3, Operand(r1, LSR, 16));
+  // Save state[0].
+  __ str(r1, FieldMemOperand(r2, ByteArray::kHeaderSize));
+
+  // state[1] = 36969 * (state[1] & 0xFFFF) + (state[1] >> 16)
+  __ and_(r3, r0, Operand(0xFFFF));
+  __ mov(r4, Operand(36969));
+  __ mul(r3, r3, r4);
+  __ add(r0, r3, Operand(r0, LSR, 16));
+  // Save state[1].
+  __ str(r0, FieldMemOperand(r2, ByteArray::kHeaderSize + kSeedSize));
+
+  // Random bit pattern = (state[0] << 14) + (state[1] & 0x3FFFF)
+  __ and_(r0, r0, Operand(0x3FFFF));
+  __ add(r0, r0, Operand(r1, LSL, 14));
 
+  __ bind(deferred->exit());
   // 0x41300000 is the top half of 1.0 x 2^20 as a double.
   // Create this constant using mov/orr to avoid PC relative load.
   __ mov(r1, Operand(0x41000000));
@@ -3253,6 +3300,13 @@ void LCodeGen::DoRandom(LRandom* instr) {
 }
 
 
+void LCodeGen::DoDeferredRandom(LRandom* instr) {
+  __ PrepareCallCFunction(1, scratch0());
+  __ CallCFunction(ExternalReference::random_uint32_function(isolate()), 1);
+  // Return value is in r0.
+}
+
+
 void LCodeGen::DoMathLog(LUnaryMathOperation* instr) {
   ASSERT(ToDoubleRegister(instr->result()).is(d2));
   TranscendentalCacheStub stub(TranscendentalCache::LOG,