VM: Improve receiver class check in polymorphic inlining.

runtime/vm/disassembler_ia32.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_IA32)
 #include "platform/utils.h"
 #include "vm/allocation.h"
@@ skipping 221 matching lines @@
     case 0x16: return "movlhps";
     case 0xA2: return "cpuid";
     case 0x31: return "rdtsc";
     case 0xBE: return "movsx_b";
     case 0xBF: return "movsx_w";
     case 0xB6: return "movzx_b";
     case 0xB7: return "movzx_w";
     case 0xAF: return "imul";
     case 0xA5: return "shld";
     case 0xAD: return "shrd";
+    case 0xA3: return "bt";
     case 0xAB: return "bts";
     case 0xBD: return "bsr";
     case 0xB1: return "cmpxchg";
     case 0x50: return "movmskps";
     case 0x51: return "sqrtps";
     case 0x52: return "rqstps";
     case 0x53: return "rcpps";
     case 0x54: return "andps";
     case 0x56: return "orps";
     case 0x57: return "xorps";
@@ skipping 1150 matching lines @@
                      *(data+3) == 0x00 &&
                      *(data+3) == 0x00 &&
                      *(data+4) == 0x00) {
             Print("nop");
             data += 8;
           } else {
             UNIMPLEMENTED();
           }
         } else {
           data += 2;
-          if (f0byte == 0xAB || f0byte == 0xA5 || f0byte == 0xAD) {
-            // shrd, shld, bts
+          if (f0byte == 0xAB ||
+              f0byte == 0xA5 ||
+              f0byte == 0xAD ||
+              f0byte == 0xA3) {
+            // shrd, shld, bts, bt
             Print(f0mnem);
             int mod, regop, rm;
             GetModRm(*data, &mod, &regop, &rm);
             Print(" ");
             data += PrintRightOperand(data);
-            if (f0byte == 0xAB) {
+            if (f0byte == 0xAB || f0byte == 0xA3) {
               Print(",");
               PrintCPURegister(regop);
             } else {
               Print(",");
               PrintCPURegister(regop);
               Print(",cl");
             }
           } else if ((f0byte == 0x10) || (f0byte == 0x11) ||
                      IsTwoXmmRegInstruction(f0byte)) {
             data = SSEInstruction(0x0F, f0byte, data);
@@ skipping 377 matching lines @@
       default:
         OS::Print("Unknown case %#x\n", *data);
         UNIMPLEMENTED();
     }
   }
 
   int instr_len = data - reinterpret_cast<uint8_t*>(pc);
   ASSERT(instr_len > 0);  // Ensure progress.
 
   return instr_len;
-}
+}  // NOLINT

[Cutch, 2014/07/09 19:22:53]

Did you add this to avoid the function length lint warning? I wonder if it would
be better to start refactoring the function to shorten its length.

[Florian Schneider, 2014/07/10 09:00:59]

Yes, I don't know if the lint warning makes sense here: The reason for this
large function is the huge switch statement, and splitting it does not make it
more readable in my opinion. It does the opposite: Making the reader jump back
and forth between helper functions that are used in exactly one place.

 
 
 void Disassembler::DecodeInstruction(char* hex_buffer, intptr_t hex_size,
                                      char* human_buffer, intptr_t human_size,
                                      int* out_instr_len, uword pc) {
   ASSERT(hex_size > 0);
   ASSERT(human_size > 0);
   X86Decoder decoder(human_buffer, human_size);
   int instruction_length = decoder.InstructionDecode(pc);
   uint8_t* pc_ptr = reinterpret_cast<uint8_t*>(pc);
@@ skipping 42 matching lines @@
                                   pc);
     pc += instruction_length;
   }
 
   return;
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32