Use USE_SIMULATOR when appropriate.

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index ae38e71c7b8e2e07dd906bbec4666a7af2aefc1a..ec9de6248fcdd32c52fe590e11d77d424c635103 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -81,15 +81,8 @@ typedef void* ExternalReferenceRedirectorPointer();
 class Debug;
 class Debugger;
 class PromiseOnStack;
-
-#if !defined(__arm__) && V8_TARGET_ARCH_ARM ||       \
-    !defined(__aarch64__) && V8_TARGET_ARCH_ARM64 || \
-    !defined(__PPC__) && V8_TARGET_ARCH_PPC ||       \
-    !defined(__mips__) && V8_TARGET_ARCH_MIPS ||     \
-    !defined(__mips__) && V8_TARGET_ARCH_MIPS64
 class Redirection;
 class Simulator;
-#endif
 
 
 // Static indirection table for handles to constants.  If a frame
@@ -321,11 +314,7 @@ class ThreadLocalTop BASE_EMBEDDED {
 };
 
 
-#if V8_TARGET_ARCH_ARM && !defined(__arm__) ||       \
-    V8_TARGET_ARCH_ARM64 && !defined(__aarch64__) || \
-    V8_TARGET_ARCH_PPC && !defined(__PPC__) ||       \
-    V8_TARGET_ARCH_MIPS && !defined(__mips__) ||     \
-    V8_TARGET_ARCH_MIPS64 && !defined(__mips__)
+#if USE_SIMULATOR
 
 #define ISOLATE_INIT_SIMULATOR_LIST(V)                                         \
   V(bool, simulator_initialized, false)                                        \
@@ -417,11 +406,7 @@ class Isolate {
           thread_id_(thread_id),
           stack_limit_(0),
           thread_state_(NULL),
-#if !defined(__arm__) && V8_TARGET_ARCH_ARM ||       \
-    !defined(__aarch64__) && V8_TARGET_ARCH_ARM64 || \
-    !defined(__PPC__) && V8_TARGET_ARCH_PPC ||       \
-    !defined(__mips__) && V8_TARGET_ARCH_MIPS ||     \
-    !defined(__mips__) && V8_TARGET_ARCH_MIPS64
+#if USE_SIMULATOR
           simulator_(NULL),
 #endif
           next_(NULL),
@@ -433,11 +418,7 @@ class Isolate {
     FIELD_ACCESSOR(uintptr_t, stack_limit)
     FIELD_ACCESSOR(ThreadState*, thread_state)
 
-#if !defined(__arm__) && V8_TARGET_ARCH_ARM ||       \
-    !defined(__aarch64__) && V8_TARGET_ARCH_ARM64 || \
-    !defined(__PPC__) && V8_TARGET_ARCH_PPC ||       \
-    !defined(__mips__) && V8_TARGET_ARCH_MIPS ||     \
-    !defined(__mips__) && V8_TARGET_ARCH_MIPS64
+#if USE_SIMULATOR
     FIELD_ACCESSOR(Simulator*, simulator)
 #endif
 
@@ -451,11 +432,7 @@ class Isolate {
     uintptr_t stack_limit_;
     ThreadState* thread_state_;
 
-#if !defined(__arm__) && V8_TARGET_ARCH_ARM ||       \
-    !defined(__aarch64__) && V8_TARGET_ARCH_ARM64 || \
-    !defined(__PPC__) && V8_TARGET_ARCH_PPC ||       \
-    !defined(__mips__) && V8_TARGET_ARCH_MIPS ||     \
-    !defined(__mips__) && V8_TARGET_ARCH_MIPS64
+#if USE_SIMULATOR
     Simulator* simulator_;
 #endif