Restore rsi on x64 when probing for CPU features.

src/x64/assembler-x64.cc

 // Copyright 2012 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 57 matching lines @@
     delete memory;
     return;
   }
 
   Assembler assm(NULL, memory->address(), kBufferSize);
   Label cpuid, done;
 #define __ assm.
   // Save old rsp, since we are going to modify the stack.
   __ push(rbp);
   __ pushfq();
+  __ push(rsi);
   __ push(rcx);
   __ push(rbx);
   __ movq(rbp, rsp);
 
   // If we can modify bit 21 of the EFLAGS register, then CPUID is supported.
   __ pushfq();
   __ pop(rax);
   __ movq(rdx, rax);
   __ xor_(rax, Immediate(0x200000));  // Flip bit 21.
   __ push(rax);
@@ skipping 33 matching lines @@
   __ not_(rax);
   __ and_(rax, rdi);
   __ or_(rax, rcx);
   __ or_(rax, Immediate(1 << CPUID));
 
   // Done.
   __ bind(&done);
   __ movq(rsp, rbp);
   __ pop(rbx);
   __ pop(rcx);
+  __ pop(rsi);
   __ popfq();
   __ pop(rbp);
   __ ret(0);
 #undef __
 
   typedef uint64_t (*F0)();
   F0 probe = FUNCTION_CAST<F0>(reinterpret_cast<Address>(memory->address()));
   supported_ = probe();
   found_by_runtime_probing_ = supported_;
   found_by_runtime_probing_ &= ~kDefaultCpuFeatures;
@@ skipping 2900 matching lines @@
 bool RelocInfo::IsCodedSpecially() {
   // The deserializer needs to know whether a pointer is specially coded.  Being
   // specially coded on x64 means that it is a relative 32 bit address, as used
   // by branch instructions.
   return (1 << rmode_) & kApplyMask;
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64