Allow a platform to indicate that some CPU features are always...

src/x64/assembler-x64.cc

 // Copyright 2009 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 62 matching lines @@
 XMMRegister xmm15 = { 15 };
 
 
 // -----------------------------------------------------------------------------
 // Implementation of CpuFeatures
 
 // The required user mode extensions in X64 are (from AMD64 ABI Table A.1):
 //   fpu, tsc, cx8, cmov, mmx, sse, sse2, fxsr, syscall
 uint64_t CpuFeatures::supported_ = kDefaultCpuFeatures;
 uint64_t CpuFeatures::enabled_ = 0;
+uint64_t CpuFeatures::found_by_runtime_probing_ = 0;
 
 void CpuFeatures::Probe()  {
   ASSERT(Heap::HasBeenSetup());
   ASSERT(supported_ == kDefaultCpuFeatures);
-  if (Serializer::enabled()) return;  // No features if we might serialize.
+  if (Serializer::enabled()) {
+    supported_ |= OS::CpuFeaturesImpliedByPlatform();
+    return;  // No features if we might serialize.
+  }
 
   Assembler assm(NULL, 0);
   Label cpuid, done;
 #define __ assm.
   // Save old rsp, since we are going to modify the stack.
   __ push(rbp);
   __ pushfq();
   __ push(rcx);
   __ push(rbx);
   __ movq(rbp, rsp);
@@ skipping 55 matching lines @@
   CodeDesc desc;
   assm.GetCode(&desc);
   Object* code =
       Heap::CreateCode(desc, NULL, Code::ComputeFlags(Code::STUB), NULL);
   if (!code->IsCode()) return;
   LOG(CodeCreateEvent(Logger::BUILTIN_TAG,
                       Code::cast(code), "CpuFeatures::Probe"));
   typedef uint64_t (*F0)();
   F0 probe = FUNCTION_CAST<F0>(Code::cast(code)->entry());
   supported_ = probe();
+  found_by_runtime_probing_ = supported_;
+  found_by_runtime_probing_ &= ~kDefaultCpuFeatures;
+  uint64_t os_guarantees = OS::CpuFeaturesImpliedByPlatform();
+  supported_ |= os_guarantees;
+  found_by_runtime_probing_ &= ~os_guarantees;
   // SSE2 and CMOV must be available on an X64 CPU.
   ASSERT(IsSupported(CPUID));
   ASSERT(IsSupported(SSE2));
   ASSERT(IsSupported(CMOV));
 }
 
 
 // -----------------------------------------------------------------------------
 // Implementation of RelocInfo
 
@@ skipping 709 matching lines @@
 void Assembler::cmpb_al(Immediate imm8) {
   ASSERT(is_int8(imm8.value_) || is_uint8(imm8.value_));
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
   emit(0x3c);
   emit(imm8.value_);
 }
 
 
 void Assembler::cpuid() {
-  ASSERT(CpuFeatures::IsEnabled(CpuFeatures::CPUID));
+  ASSERT(CpuFeatures::IsEnabled(CPUID));
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
   emit(0x0F);
   emit(0xA2);
 }
 
 
 void Assembler::cqo() {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
@@ skipping 1137 matching lines @@
 void Assembler::fistp_s(const Operand& adr) {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xDB);
   emit_operand(3, adr);
 }
 
 
 void Assembler::fisttp_s(const Operand& adr) {
-  ASSERT(CpuFeatures::IsEnabled(CpuFeatures::SSE3));
+  ASSERT(CpuFeatures::IsEnabled(SSE3));
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xDB);
   emit_operand(1, adr);
 }
 
 
 void Assembler::fist_s(const Operand& adr) {
   EnsureSpace ensure_space(this);
@@ skipping 460 matching lines @@
     written_position_ = current_position_;
   }
 }
 
 
 const int RelocInfo::kApplyMask = RelocInfo::kCodeTargetMask |
                                   1 << RelocInfo::INTERNAL_REFERENCE |
                                   1 << RelocInfo::JS_RETURN;
 
 } }  // namespace v8::internal