Introduce BUILTIN_CALL_PAIR.

src/ppc/simulator-ppc.cc

Index: src/ppc/simulator-ppc.cc
diff --git a/src/ppc/simulator-ppc.cc b/src/ppc/simulator-ppc.cc
index 75074317a6d258c1b0b60cf2336121fba3021ef9..e9c94044958c84e23de1e60664d3dc8aa49f0c9e 100644
--- a/src/ppc/simulator-ppc.cc
+++ b/src/ppc/simulator-ppc.cc
@@ -1188,17 +1188,13 @@ static void decodeObjectPair(ObjectPair* pair, intptr_t* x, intptr_t* y) {
 }
 #endif
 
-// Calls into the V8 runtime are based on this very simple interface.
-// Note: To be able to return two values from some calls the code in
-// runtime.cc uses the ObjectPair which is essentially two pointer
-// values stuffed into a structure. With the code below we assume that
-// all runtime calls return this pair. If they don't, the r4 result
-// register contains a bogus value, which is fine because it is
-// caller-saved.
-typedef ObjectPair (*SimulatorRuntimeCall)(intptr_t arg0, intptr_t arg1,
-                                           intptr_t arg2, intptr_t arg3,
-                                           intptr_t arg4, intptr_t arg5);
-
+// Calls into the V8 runtime.
+typedef intptr_t (*SimulatorRuntimeCall)(intptr_t arg0, intptr_t arg1,
+                                         intptr_t arg2, intptr_t arg3,
+                                         intptr_t arg4, intptr_t arg5);
+typedef ObjectPair (*SimulatorRuntimePairCall)(intptr_t arg0, intptr_t arg1,
+                                               intptr_t arg2, intptr_t arg3,
+                                               intptr_t arg4, intptr_t arg5);
 typedef ObjectTriple (*SimulatorRuntimeTripleCall)(intptr_t arg0, intptr_t arg1,
                                                    intptr_t arg2, intptr_t arg3,
                                                    intptr_t arg4,
@@ -1236,7 +1232,9 @@ void Simulator::SoftwareInterrupt(Instruction* instr) {
       int arg0_regnum = 3;
       intptr_t result_buffer = 0;
       bool uses_result_buffer =
-          redirection->type() == ExternalReference::BUILTIN_CALL_TRIPLE;
+          redirection->type() == ExternalReference::BUILTIN_CALL_TRIPLE ||
+          (redirection->type() == ExternalReference::BUILTIN_CALL_PAIR &&
+           !ABI_RETURNS_OBJECT_PAIRS_IN_REGS);
       if (uses_result_buffer) {
         result_buffer = get_register(r3);
         arg0_regnum++;
@@ -1443,19 +1441,36 @@ void Simulator::SoftwareInterrupt(Instruction* instr) {
                  sizeof(ObjectTriple));
           set_register(r3, result_buffer);
         } else {
-          DCHECK(redirection->type() == ExternalReference::BUILTIN_CALL);
-          SimulatorRuntimeCall target =
-              reinterpret_cast<SimulatorRuntimeCall>(external);
-          ObjectPair result =
-              target(arg[0], arg[1], arg[2], arg[3], arg[4], arg[5]);
-          intptr_t x;
-          intptr_t y;
-          decodeObjectPair(&result, &x, &y);
-          if (::v8::internal::FLAG_trace_sim) {
-            PrintF("Returned {%08" V8PRIxPTR ", %08" V8PRIxPTR "}\n", x, y);
+          if (redirection->type() == ExternalReference::BUILTIN_CALL_PAIR) {
+            SimulatorRuntimePairCall target =
+                reinterpret_cast<SimulatorRuntimePairCall>(external);
+            ObjectPair result =
+                target(arg[0], arg[1], arg[2], arg[3], arg[4], arg[5]);
+            intptr_t x;
+            intptr_t y;
+            decodeObjectPair(&result, &x, &y);
+            if (::v8::internal::FLAG_trace_sim) {
+              PrintF("Returned {%08" V8PRIxPTR ", %08" V8PRIxPTR "}\n", x, y);
+            }
+            if (ABI_RETURNS_OBJECT_PAIRS_IN_REGS) {
+              set_register(r3, x);
+              set_register(r4, y);
+            } else {
+              memcpy(reinterpret_cast<void*>(result_buffer), &result,
+                     sizeof(ObjectPair));
+              set_register(r3, result_buffer);
+            }
+          } else {
+            DCHECK(redirection->type() == ExternalReference::BUILTIN_CALL);
+            SimulatorRuntimeCall target =
+                reinterpret_cast<SimulatorRuntimeCall>(external);
+            intptr_t result =
+                target(arg[0], arg[1], arg[2], arg[3], arg[4], arg[5]);
+            if (::v8::internal::FLAG_trace_sim) {
+              PrintF("Returned %08" V8PRIxPTR "\n", result);
+            }
+            set_register(r3, result);
           }
-          set_register(r3, x);
-          set_register(r4, y);
         }
       }
       set_pc(saved_lr);