ARM backend support for pld (preload data) instruction

src/arm/disasm-arm.cc

Index: src/arm/disasm-arm.cc
===================================================================
--- src/arm/disasm-arm.cc	(revision 13713)
+++ src/arm/disasm-arm.cc	(working copy)
@@ -557,9 +557,14 @@
       return 4;
     }
     case 'p': {  // 'pu: P and U bits for load and store instructions
-      ASSERT(STRING_STARTS_WITH(format, "pu"));
-      PrintPU(instr);
-      return 2;
+      if (STRING_STARTS_WITH(format, "pu")) {
+        PrintPU(instr);
+        return 2;
+      } else {
+        ASSERT(STRING_STARTS_WITH(format, "preload"));
+        Print("pld");
+        return 7;
+      }
     }
     case 'r': {
       return FormatRegister(instr, format);
@@ -956,11 +961,19 @@
       break;
     }
     case db_x: {
-      Format(instr, "'memop'cond'b 'rd, ['rn, #-'off12]'w");
+      if (instr->ConditionField() == kSpecialCondition) {
+        Format(instr, "'preload ['rn, #-'off12]");
+      } else {
+        Format(instr, "'memop'cond'b 'rd, ['rn, #-'off12]'w");
+      }
       break;
     }
     case ib_x: {
-      Format(instr, "'memop'cond'b 'rd, ['rn, #+'off12]'w");
+      if (instr->ConditionField() == kSpecialCondition) {
+        Format(instr, "'preload ['rn, #+'off12]");
+      } else {
+        Format(instr, "'memop'cond'b 'rd, ['rn, #+'off12]'w");
+      }
       break;
     }
     default: {
@@ -1004,7 +1017,11 @@
           }
         }
       }
-      Format(instr, "'memop'cond'b 'rd, ['rn, -'shift_rm]'w");
+      if (instr->ConditionField() == kSpecialCondition) {
+        Format(instr, "'preload ['rn, -'shift_rm]");
+      } else {
+        Format(instr, "'memop'cond'b 'rd, ['rn, -'shift_rm]'w");
+      }
       break;
     }
     case ib_x: {
@@ -1033,6 +1050,8 @@
         } else {
           UNREACHABLE();
         }
+      } else if (instr->ConditionField() == kSpecialCondition) {
+        Format(instr, "'preload ['rn, +'shift_rm]");
       } else {
         Format(instr, "'memop'cond'b 'rd, ['rn, +'shift_rm]'w");
       }
@@ -1431,7 +1450,7 @@
   out_buffer_pos_ += OS::SNPrintF(out_buffer_ + out_buffer_pos_,
                                   "%08x       ",
                                   instr->InstructionBits());
-  if (instr->ConditionField() == kSpecialCondition) {
+  if (instr->ConditionField() == kSpecialCondition && !instr->IsPld()) {
     Unknown(instr);
     return Instruction::kInstrSize;
   }