[AArch64-instr-info] Define a DEBUG_TYPE for AArch64-instr-info.

[mingmingl]

Summary

In this way, we could use llc -debug-only=aarch64-instr-info <file.ll> to see the LLVM_DEBUG logs.

[dmgreen]

Do you plan to add LLVM_DEBUG statements? If so it probably makes sense to add the DEBUG_TYPE when they are added. As far as I understand, it doesn't do much on it's own :)

[mingmingl]

In D124949#3491912, @dmgreen wrote:

Do you plan to add LLVM_DEBUG statements? If so it probably makes sense to add the DEBUG_TYPE when they are added. As far as I understand, it doesn't do much on it's own :)

Ah this is a good point.

I had a command like llc -O3 -march=aarch64 -debug -debug-only=isel,aarch64-isel,selectiondag,legalizedag,<aarch64-instr-info-to-be-added> to dump the logs that are related, but I didn't realize this cpp doesn't have LLVM_DEBUG at this point. Makes sense to add DEBUT_TYPE until there are LLVM_DEBUG statements needed.

Will abandon this.

llvm/lib/Target/AArch64/AArch64InstrInfo.cpp

 #include "llvm/Target/TargetOptions.h"
 #include <cassert>
 #include <cstdint>
 #include <iterator>
 #include <utility>
 
 using namespace llvm;
 
+#define DEBUG_TYPE "aarch64-instr-info"
+
 #define GET_INSTRINFO_CTOR_DTOR
 #include "AArch64GenInstrInfo.inc"
 
 static cl::opt<unsigned> TBZDisplacementBits(
     "aarch64-tbz-offset-bits", cl::Hidden, cl::init(14),
     cl::desc("Restrict range of TB[N]Z instructions (DEBUG)"));
 
 static cl::opt<unsigned> CBZDisplacementBits(