[llvm-objdump] Add '0x' prefix to a target displacement number to accent its hex format

[atanasyan]

Summary

It might be hard to recognize a hexadecimal number without '0x' prefix. Besides that '0x' prefix corresponds to GNU objdump behaviour.

[• rafael]

LGTM

test/tools/llvm-objdump/hex-displacement.test

+# Check that target displacement has '0x' prefix
+# to accent hex format of the number.
+
+# RUN: llvm-objdump -d %p/Inputs/export.dll.coff-i386 | FileCheck %s
+
+# CHECK:      exportfn2:
+# CHECK-NEXT: 10002010:       50      pushl   %eax
+# CHECK-NEXT: 10002011:       e8 00 00 00 00  calll   0 <exportfn2+0x6>
+# CHECK-NEXT: 10002016:       50      pushl   %eax
+# CHECK-NEXT: 10002017:       e8 00 00 00 00  calll   0 <exportfn2+0xC>

tools/llvm-objdump/llvm-objdump.cpp

#endif
                     });
                 if (TargetSym != TargetSectionSymbols->begin()) {
                   --TargetSym;
                   uint64_t TargetAddress = std::get<0>(*TargetSym);
                   StringRef TargetName = std::get<1>(*TargetSym);
                   outs() << " <" << TargetName;
                   uint64_t Disp = Target - TargetAddress;
                   if (Disp)
-                    outs() << '+' << utohexstr(Disp);
+                    outs() << "+0x" << utohexstr(Disp);
                   outs() << '>';
                 }
               }
             }
           }
           outs() << "\n";
         } else {
           errs() << ToolName << ": warning: invalid instruction encoding\n";