MIPS: port ARM: Changed the handling of compiletime CPU feature detection

src/mips/assembler-mips.cc

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // 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.
 //
@@ skipping 31 matching lines @@
 
 namespace v8 {
 namespace internal {
 
 #ifdef DEBUG
 bool CpuFeatures::initialized_ = false;
 #endif
 unsigned CpuFeatures::supported_ = 0;
 unsigned CpuFeatures::found_by_runtime_probing_ = 0;
 
+
+// Get the CPU features enabled by the build. For cross compilation the
+// preprocessor symbols CAN_USE_FPU_INSTRUCTIONS
+// can be defined to enable FPU instructions when building the
+// snapshot.
+static uint64_t CpuFeaturesImpliedByCompiler() {
+  uint64_t answer = 0;
+#ifdef CAN_USE_FPU_INSTRUCTIONS
+  answer |= 1u << FPU;
+#endif  // def CAN_USE_FPU_INSTRUCTIONS
+
+#ifdef __mips__
+  // If the compiler is allowed to use FPU then we can use FPU too in our code
+  // generation even when generating snapshots.  This won't work for cross
+  // compilation.
+#if(defined(__mips_hard_float) && __mips_hard_float != 0)
+  answer |= 1u << FPU;
+#endif  // defined(__mips_hard_float) && __mips_hard_float != 0
+#endif  // def __mips__
+
+  return answer;
+}
+
+
 void CpuFeatures::Probe() {
   ASSERT(!initialized_);
 #ifdef DEBUG
   initialized_ = true;
 #endif
+
+  // Get the features implied by the OS and the compiler settings. This is the
+  // minimal set of features which is also allowed for generated code in the
+  // snapshot.
+  supported_ |= OS::CpuFeaturesImpliedByPlatform();
+  supported_ |= CpuFeaturesImpliedByCompiler();
+
+  if (Serializer::enabled()) {
+    // No probing for features if we might serialize (generate snapshot).
+    return;
+  }
+
   // If the compiler is allowed to use fpu then we can use fpu too in our
   // code generation.
 #if !defined(__mips__)
   // For the simulator=mips build, use FPU when FLAG_enable_fpu is enabled.
   if (FLAG_enable_fpu) {
       supported_ |= 1u << FPU;
   }
 #else
-  if (Serializer::enabled()) {
-    supported_ |= OS::CpuFeaturesImpliedByPlatform();
-    return;  // No features if we might serialize.
-  }
-
+  // Probe for additional features not already known to be available.
   if (OS::MipsCpuHasFeature(FPU)) {
     // This implementation also sets the FPU flags if
     // runtime detection of FPU returns true.
     supported_ |= 1u << FPU;
     found_by_runtime_probing_ |= 1u << FPU;
   }
 #endif
 }
 
 
@@ skipping 1979 matching lines @@
   *p = LUI | rt_code | ((itarget & kHiMask) >> kLuiShift);
   *(p+1) = ORI | rt_code | (rt_code << 5) | (itarget & kImm16Mask);
 
   CPU::FlushICache(pc, 2 * sizeof(int32_t));
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS