ARM: honor hex immediate formatting for ldr/str i12 offsets.

Previously we would always print the offset as decimal, regardless of
the formatting requested. Now we use the formatImm() helper so the value
is printed as the client (LLDB in the motivating example) requested.

Before:
ldr.w r8, [sp, #180] @ always

After:
ldr.w r8, [sp, #0xb4] @ when printing hex immediates
ldr.w r8, [sp, #0180] @ when printing decimal immediates

rdar://17237103

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210701 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp

@@ -1092,13 +1092,13 @@ void ARMInstPrinter::printAddrModeImm12Operand(const MCInst *MI, unsigned OpNum,
   if (isSub) {
     O << ", "
       << markup("<imm:")
-      << "#-" << -OffImm
+      << "#-" << formatImm(-OffImm)
       << markup(">");
   }
   else if (AlwaysPrintImm0 || OffImm > 0) {
     O << ", "
       << markup("<imm:")
-      << "#" << OffImm
+      << "#" << formatImm(OffImm)
       << markup(">");
   }
   O << "]" << markup(">");

test/MC/Disassembler/ARM/hex-immediates.txt

@@ -3,3 +3,9 @@
 0x08 0x4c
 # CHECK: sub	sp, #0x84
 0xa1 0xb0
+# CHECK: ldr  r0, [sp, #0xb4]
+0x2d 0x98
+# CHECK: str.w  r8, [sp, #0xb4]
+0xcd 0xf8 0xb4 0x80
+# CHECK: ldr.w  r8, [sp, #0xb4]
+0xdd 0xf8 0xb4 0x80