[NOT FOR COMMIT] Native Client builds of V8 on ia32 and x64.

src/arm/simulator-arm.cc

Index: src/arm/simulator-arm.cc
diff --git a/src/arm/simulator-arm.cc b/src/arm/simulator-arm.cc
index 2551e14e4905932a4ad5bd853307bb6c941fac68..731113e20f45ad7aee5688e1f16f8e050036b0aa 100644
--- a/src/arm/simulator-arm.cc
+++ b/src/arm/simulator-arm.cc
@@ -1647,10 +1647,25 @@ typedef int64_t (*SimulatorRuntimeCall)(int32_t arg0,
                                         int32_t arg3,
                                         int32_t arg4,
                                         int32_t arg5);
+#if defined(V8_ARM_ON_X86_64)
+// This prototype will handle calls with up to two double args
+// and up to four integer args in any order. Note that arguments
+// on x86_64 are passed in registers. With this prototype the
+// six cited argument registers are loaded. Note that the callee
+// will simply ignore any arguments it doesn't actually need.
+// This prototype will fail for structures passed by value.
+typedef double (*SimulatorRuntimeFPCall)(double darg0,
+                                         double darg1,
+                                         int32_t arg0,
+                                         int32_t arg1,
+                                         int32_t arg2,
+                                         int32_t arg3);
+#else
 typedef double (*SimulatorRuntimeFPCall)(int32_t arg0,
                                          int32_t arg1,
                                          int32_t arg2,
                                          int32_t arg3);
+#endif
 
 // This signature supports direct call in to API function native callback
 // (refer to InvocationCallback in v8.h).
@@ -1660,6 +1675,16 @@ typedef v8::Handle<v8::Value> (*SimulatorRuntimeDirectApiCall)(int32_t arg0);
 typedef v8::Handle<v8::Value> (*SimulatorRuntimeDirectGetterCall)(int32_t arg0,
                                                                   int32_t arg1);
 
+
+#if defined(V8_ARM_ON_X86_64)
+static double ArgAsDouble(uint32_t lo, uint32_t hi) {
+  union { uint64_t i64; double d; } darg;
+  darg.i64 = hi;
+  darg.i64 = (darg.i64 << 32) | lo;
+  return darg.d;
+}
+#endif
+
 // Software interrupt instructions are used by the simulator to call into the
 // C-based V8 runtime.
 void Simulator::SoftwareInterrupt(Instruction* instr) {
@@ -1751,7 +1776,13 @@ void Simulator::SoftwareInterrupt(Instruction* instr) {
         if (redirection->type() != ExternalReference::BUILTIN_COMPARE_CALL) {
           SimulatorRuntimeFPCall target =
               reinterpret_cast<SimulatorRuntimeFPCall>(external);
+#if defined(V8_ARM_ON_X86_64)
+          double result = target(ArgAsDouble(arg0, arg1),
+                                 ArgAsDouble(arg2, arg3),
+                                 arg0, arg1, arg2, arg3);
+#else
           double result = target(arg0, arg1, arg2, arg3);
+#endif
           SetFpResult(result);
         } else {
           SimulatorRuntimeCall target =