Direct call api functions (arm implementation)

src/arm/simulator-arm.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 30 matching lines @@
 
 // Only build the simulator if not compiling for real ARM hardware.
 namespace assembler {
 namespace arm {
 
 using ::v8::internal::Object;
 using ::v8::internal::PrintF;
 using ::v8::internal::OS;
 using ::v8::internal::ReadLine;
 using ::v8::internal::DeleteArray;
+using ::v8::internal::ExternalReference;
 
 // This macro provides a platform independent use of sscanf. The reason for
 // SScanF not being implemented in a platform independent way through
 // ::v8::internal::OS in the same way as SNPrintF is that the
 // Windows C Run-Time Library does not provide vsscanf.
 #define SScanF sscanf  // NOLINT
 
 // The Debugger class is used by the simulator while debugging simulated ARM
 // code.
 class Debugger {
@@ skipping 677 matching lines @@
 
 // When the generated code calls an external reference we need to catch that in
 // the simulator.  The external reference will be a function compiled for the
 // host architecture.  We need to call that function instead of trying to
 // execute it with the simulator.  We do that by redirecting the external
 // reference to a svc (Supervisor Call) instruction that is handled by
 // the simulator.  We write the original destination of the jump just at a known
 // offset from the svc instruction so the simulator knows what to call.
 class Redirection {
  public:
-  Redirection(void* external_function, bool fp_return)
+  Redirection(void* external_function, ExternalReference::Type type)
       : external_function_(external_function),
         swi_instruction_((AL << 28) | (0xf << 24) | call_rt_redirected),
-        fp_return_(fp_return),
+        type_(type),
         next_(list_) {
     Simulator::current()->
         FlushICache(reinterpret_cast<void*>(&swi_instruction_),
                       Instr::kInstrSize);
     list_ = this;
   }
 
   void* address_of_swi_instruction() {
     return reinterpret_cast<void*>(&swi_instruction_);
   }
 
   void* external_function() { return external_function_; }
-  bool fp_return() { return fp_return_; }
+  ExternalReference::Type type() { return type_; }
 
-  static Redirection* Get(void* external_function, bool fp_return) {
+  static Redirection* Get(void* external_function,
+                          ExternalReference::Type type) {
     Redirection* current;
     for (current = list_; current != NULL; current = current->next_) {
       if (current->external_function_ == external_function) return current;
     }
-    return new Redirection(external_function, fp_return);
+    return new Redirection(external_function, type);
   }
 
   static Redirection* FromSwiInstruction(Instr* swi_instruction) {
     char* addr_of_swi = reinterpret_cast<char*>(swi_instruction);
     char* addr_of_redirection =
         addr_of_swi - OFFSET_OF(Redirection, swi_instruction_);
     return reinterpret_cast<Redirection*>(addr_of_redirection);
   }
 
  private:
   void* external_function_;
   uint32_t swi_instruction_;
-  bool fp_return_;
+  ExternalReference::Type type_;
   Redirection* next_;
   static Redirection* list_;
 };
 
 
 Redirection* Redirection::list_ = NULL;
 
 
 void* Simulator::RedirectExternalReference(void* external_function,
-                                           bool fp_return) {
-  Redirection* redirection = Redirection::Get(external_function, fp_return);
+                                           ExternalReference::Type type) {
+  Redirection* redirection = Redirection::Get(external_function, type);
   return redirection->address_of_swi_instruction();
 }
 
 
 // Get the active Simulator for the current thread.
 Simulator* Simulator::current() {
   Initialize();
   Simulator* sim = reinterpret_cast<Simulator*>(
       v8::internal::Thread::GetThreadLocal(simulator_key));
   if (sim == NULL) {
@@ skipping 720 matching lines @@
 typedef int64_t (*SimulatorRuntimeCall)(int32_t arg0,
                                         int32_t arg1,
                                         int32_t arg2,
                                         int32_t arg3,
                                         int32_t arg4);
 typedef double (*SimulatorRuntimeFPCall)(int32_t arg0,
                                          int32_t arg1,
                                          int32_t arg2,
                                          int32_t arg3);
 
+// This signature supports direct call in to API function native callback
+// (refer to InvocationCallback in v8.h).
+typedef v8::Handle<v8::Value> (*SimulatorRuntimeApiCall)(int32_t arg0);
 
 // Software interrupt instructions are used by the simulator to call into the
 // C-based V8 runtime.
 void Simulator::SoftwareInterrupt(Instr* instr) {
   int svc = instr->SvcField();
   switch (svc) {
     case call_rt_redirected: {
       // Check if stack is aligned. Error if not aligned is reported below to
       // include information on the function called.
       bool stack_aligned =
           (get_register(sp)
            & (::v8::internal::FLAG_sim_stack_alignment - 1)) == 0;
       Redirection* redirection = Redirection::FromSwiInstruction(instr);
       int32_t arg0 = get_register(r0);
       int32_t arg1 = get_register(r1);
       int32_t arg2 = get_register(r2);
       int32_t arg3 = get_register(r3);
       int32_t* stack_pointer = reinterpret_cast<int32_t*>(get_register(sp));
       int32_t arg4 = *stack_pointer;
       // This is dodgy but it works because the C entry stubs are never moved.
       // See comment in codegen-arm.cc and bug 1242173.
       int32_t saved_lr = get_register(lr);
-      if (redirection->fp_return()) {
-        intptr_t external =
-            reinterpret_cast<intptr_t>(redirection->external_function());
+      intptr_t external =
+          reinterpret_cast<intptr_t>(redirection->external_function());
+      if (redirection->type() == ExternalReference::FP_RETURN_CALL) {
         SimulatorRuntimeFPCall target =
             reinterpret_cast<SimulatorRuntimeFPCall>(external);
         if (::v8::internal::FLAG_trace_sim || !stack_aligned) {
           double x, y;
           GetFpArgs(&x, &y);
           PrintF("Call to host function at %p with args %f, %f",
                  FUNCTION_ADDR(target), x, y);
           if (!stack_aligned) {
             PrintF(" with unaligned stack %08x\n", get_register(sp));
           }
           PrintF("\n");
         }
         CHECK(stack_aligned);
         double result = target(arg0, arg1, arg2, arg3);
         SetFpResult(result);
+      } else if (redirection->type() == ExternalReference::DIRECT_CALL) {
+        SimulatorRuntimeApiCall target =
+            reinterpret_cast<SimulatorRuntimeApiCall>(external);
+        if (::v8::internal::FLAG_trace_sim || !stack_aligned) {
+          PrintF(
+              "Call to host function at %p args %08x",
+              FUNCTION_ADDR(target),
+              arg0);
+          if (!stack_aligned) {
+            PrintF(" with unaligned stack %08x\n", get_register(sp));
+          }
+          PrintF("\n");
+        }
+        CHECK(stack_aligned);
+        v8::Handle<v8::Value> result = target(arg0);
+        if (::v8::internal::FLAG_trace_sim) {
+          PrintF("Returned %p\n", reinterpret_cast<void *>(*result));
+        }
+        set_register(r0, (int32_t) *result);
       } else {

[Erik Corry, 2011/01/24 21:45:16]

The usual pattern in V8 is to add a line here saying something like.
ASSERT(redirection->type() == ExternalReference::...)
which serves as a check and also a comment that aids the reader.

[Zaheer, 2011/01/25 07:39:52]

Done.

-        intptr_t external =
-            reinterpret_cast<int32_t>(redirection->external_function());
         SimulatorRuntimeCall target =
             reinterpret_cast<SimulatorRuntimeCall>(external);
         if (::v8::internal::FLAG_trace_sim || !stack_aligned) {
           PrintF(
               "Call to host function at %p args %08x, %08x, %08x, %08x, %0xc",
               FUNCTION_ADDR(target),
               arg0,
               arg1,
               arg2,
               arg3,
@@ skipping 1455 matching lines @@
   uintptr_t address = *stack_slot;
   set_register(sp, current_sp + sizeof(uintptr_t));
   return address;
 }
 
 } }  // namespace assembler::arm
 
 #endif  // USE_SIMULATOR
 
 #endif  // V8_TARGET_ARCH_ARM