A third attempt to provide correct conversion specifiers on MacOS.

runtime/vm/disassembler_x64.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/disassembler.h"
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_IA32.
 #if defined(TARGET_ARCH_X64)
 #include "platform/utils.h"
 #include "vm/allocation.h"
@@ skipping 541 matching lines @@
       break;
     case QUADWORD_SIZE:
       value = *reinterpret_cast<int32_t*>(data);
       count = 4;
       break;
     default:
       UNREACHABLE();
       value = 0;  // Initialize variables on all paths to satisfy the compiler.
       count = 0;
   }
-  AppendToBuffer("%#"Px"", value);
+  AppendToBuffer("%#"Px64"", value);
   return count;
 }
 
 
 // Returns number of bytes used by machine instruction, including *data byte.
 // Writes immediate instructions to 'tmp_buffer_'.
 int DisassemblerX64::PrintImmediateOp(uint8_t* data) {
   bool byte_size_immediate = (*data & 0x02) != 0;
   uint8_t modrm = *(data + 1);
   int mod, regop, rm;
@@ skipping 1175 matching lines @@
             value = *reinterpret_cast<uint32_t*>(data + 1);
             data += 5;
             break;
           case QUADWORD_SIZE:
             value = *reinterpret_cast<int32_t*>(data + 1);
             data += 5;
             break;
           default:
             UNREACHABLE();
         }
-        AppendToBuffer("test%c rax,%#"Px"",
+        AppendToBuffer("test%c rax,%#"Px64"",
                        operand_size_code(),
                        value);
         break;
       }
       case 0xD1:  // fall through
       case 0xD3:  // fall through
       case 0xC1:
         data += ShiftInstruction(data);
         break;
       case 0xD0:  // fall through
@@ skipping 87 matching lines @@
                                   human_buffer,
                                   sizeof(human_buffer),
                                   pc);
     pc += instruction_length;
   }
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64