Fix printf formats

src/x64/disasm-x64.cc

Index: src/x64/disasm-x64.cc
diff --git a/src/x64/disasm-x64.cc b/src/x64/disasm-x64.cc
index a9532dc3ad9b97f8f238cefa7450b26c002dbed4..ff5ce3b3a3ca9c68a27da81fd619e6a59d278acb 100644
--- a/src/x64/disasm-x64.cc
+++ b/src/x64/disasm-x64.cc
@@ -8,6 +8,7 @@
 
 #if V8_TARGET_ARCH_X64
 
+#include "src/base/compiler-specific.h"
 #include "src/base/lazy-instance.h"
 #include "src/disasm.h"
 
@@ -479,7 +480,7 @@ class DisassemblerX64 {
   int MemoryFPUInstruction(int escape_opcode, int regop, byte* modrm_start);
   int RegisterFPUInstruction(int escape_opcode, byte modrm_byte);
   int AVXInstruction(byte* data);
-  void AppendToBuffer(const char* format, ...);
+  PRINTF_FORMAT(2, 3) void AppendToBuffer(const char* format, ...);
 
   void UnimplementedInstruction() {
     if (abort_on_unimplemented_) {
@@ -618,7 +619,7 @@ int DisassemblerX64::PrintImmediate(byte* data, OperandSize size) {
       value = 0;  // Initialize variables on all paths to satisfy the compiler.
       count = 0;
   }
-  AppendToBuffer("%" V8_PTR_PREFIX "x", value);
+  AppendToBuffer("%" PRIx64, value);
   return count;
 }
 
@@ -1999,7 +2000,7 @@ int DisassemblerX64::InstructionDecode(v8::internal::Vector<char> out_buffer,
           if (rex_w()) AppendToBuffer("REX.W ");
           AppendToBuffer("%s%c", idesc.mnem, operand_size_code());
         } else {
-          AppendToBuffer("%s", idesc.mnem, operand_size_code());
+          AppendToBuffer("%s%c", idesc.mnem, operand_size_code());
         }
         data++;
         break;
@@ -2334,9 +2335,7 @@ int DisassemblerX64::InstructionDecode(v8::internal::Vector<char> out_buffer,
           default:
             UNREACHABLE();
         }
-        AppendToBuffer("test%c rax,0x%" V8_PTR_PREFIX "x",
-                       operand_size_code(),
-                       value);
+        AppendToBuffer("test%c rax,0x%" PRIx64, operand_size_code(), value);
         break;
       }
       case 0xD1:  // fall through