diff --git a/runtime/platform/globals.h b/runtime/platform/globals.h
index ed20219f303..7d695485a73 100644
--- a/runtime/platform/globals.h
+++ b/runtime/platform/globals.h
@@ -356,9 +356,13 @@ typedef simd128_value_t fpu_register_t;
 
 // Determine whether we will be using the simulator.
 #if defined(TARGET_ARCH_IA32)
-// No simulator used.
+#if !defined(HOST_ARCH_IA32)
+#define USING_SIMULATOR 1
+#endif
 #elif defined(TARGET_ARCH_X64)
-// No simulator used.
+#if !defined(HOST_ARCH_X64)
+#define USING_SIMULATOR 1
+#endif
 #elif defined(TARGET_ARCH_ARM)
 #if !defined(HOST_ARCH_ARM)
 #define TARGET_HOST_MISMATCH 1
diff --git a/runtime/vm/cpu_arm64.cc b/runtime/vm/cpu_arm64.cc
index e27ac58d59e..d193d23809e 100644
--- a/runtime/vm/cpu_arm64.cc
+++ b/runtime/vm/cpu_arm64.cc
@@ -64,7 +64,7 @@ const char* CPU::Id() {
   return
 #if defined(USING_SIMULATOR)
       "sim"
-#endif  // !defined(HOST_ARCH_ARM64)
+#endif  // !defined(USING_SIMULATOR)
       "arm64";
 }
 
diff --git a/runtime/vm/cpu_ia32.cc b/runtime/vm/cpu_ia32.cc
index a2ed12853c6..27ae5c549f1 100644
--- a/runtime/vm/cpu_ia32.cc
+++ b/runtime/vm/cpu_ia32.cc
@@ -24,7 +24,11 @@ void CPU::FlushICache(uword start, uword size) {
 }
 
 const char* CPU::Id() {
-  return "ia32";
+  return
+#if defined(USING_SIMULATOR)
+      "sim"
+#endif  // !defined(USING_SIMULATOR)
+      "ia32";
 }
 
 const char* HostCPUFeatures::hardware_ = nullptr;
diff --git a/runtime/vm/cpu_x64.cc b/runtime/vm/cpu_x64.cc
index 7f5981c8a33..cf0acf3798c 100644
--- a/runtime/vm/cpu_x64.cc
+++ b/runtime/vm/cpu_x64.cc
@@ -23,7 +23,11 @@ void CPU::FlushICache(uword start, uword size) {
 }
 
 const char* CPU::Id() {
-  return "x64";
+  return
+#if defined(USING_SIMULATOR)
+      "sim"
+#endif  // !defined(USING_SIMULATOR)
+      "x64";
 }
 
 const char* HostCPUFeatures::hardware_ = nullptr;
diff --git a/runtime/vm/simulator.h b/runtime/vm/simulator.h
index 3194aa918fd..e08337c9b30 100644
--- a/runtime/vm/simulator.h
+++ b/runtime/vm/simulator.h
@@ -9,8 +9,7 @@
 
 #if defined(USING_SIMULATOR)
 #if defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64)
-// No simulator used.
-#error Simulator not supported.
+#error Simulator not implemented.
 #elif defined(TARGET_ARCH_ARM)
 #include "vm/simulator_arm.h"
 #elif defined(TARGET_ARCH_ARM64)