llvm/lib/TableGen/TableGenBackendSkeleton.cpp

   1 //===- SkeletonEmitter.cpp - Skeleton TableGen backend          -*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This Tablegen backend emits ...
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/ADT/DenseMapInfo.h"
  14 #include "llvm/ADT/StringRef.h"
  15 #include "llvm/TableGen/TableGenBackend.h"
  16
  17 #define DEBUG_TYPE "skeleton-emitter"
  18
  19 namespace llvm {
  20 class RecordKeeper;
  21 class raw_ostream;
  22 } // namespace llvm
  23
  24 using namespace llvm;
  25
  26 namespace {
  27
  28 // Any helper data structures can be defined here. Some backends use
  29 // structs to collect information from the records.
  30
  31 class SkeletonEmitter {
  32 private:
  33   RecordKeeper &Records;
  34
  35 public:
  36   SkeletonEmitter(RecordKeeper &RK) : Records(RK) {}
  37
  38   void run(raw_ostream &OS);
  39 }; // emitter class
  40
  41 } // anonymous namespace
  42
  43 void SkeletonEmitter::run(raw_ostream &OS) {
  44   emitSourceFileHeader("Skeleton data structures", OS);
  45
  46   (void)Records; // To suppress unused variable warning; remove on use.
  47 }
  48
  49 // Choose either option A or B.
  50
  51 //===----------------------------------------------------------------------===//
  52 // Option A: Register the backed as class <SkeletonEmitter>
  53 static TableGen::Emitter::OptClass<SkeletonEmitter>
  54     X("gen-skeleton-class", "Generate example skeleton class");
  55
  56 //===----------------------------------------------------------------------===//
  57 // Option B: Register "EmitSkeleton" directly
  58 // The emitter entry may be private scope.
  59 static void EmitSkeleton(RecordKeeper &RK, raw_ostream &OS) {
  60   // Instantiate the emitter class and invoke run().
  61   SkeletonEmitter(RK).run(OS);
  62 }
  63
  64 static TableGen::Emitter::Opt Y("gen-skeleton-entry", EmitSkeleton,
  65                                 "Generate example skeleton entry");