185 lines · cpp
1//===- JSONBackend.cpp - Generate a JSON dump of all records. -*- 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-exception6//7//===----------------------------------------------------------------------===//8//9// This TableGen back end generates a machine-readable representation10// of all the classes and records defined by the input, in JSON format.11//12//===----------------------------------------------------------------------===//13 14#include "llvm/Support/Casting.h"15#include "llvm/Support/Debug.h"16#include "llvm/Support/JSON.h"17#include "llvm/TableGen/Error.h"18#include "llvm/TableGen/Record.h"19 20#define DEBUG_TYPE "json-emitter"21 22using namespace llvm;23 24namespace {25 26class JSONEmitter {27private:28 const RecordKeeper &Records;29 30 json::Value translateInit(const Init &I);31 32public:33 explicit JSONEmitter(const RecordKeeper &R) : Records(R) {}34 35 void run(raw_ostream &OS);36};37 38} // end anonymous namespace39 40json::Value JSONEmitter::translateInit(const Init &I) {41 // Init subclasses that we return as JSON primitive values of one42 // kind or another.43 44 if (isa<UnsetInit>(&I))45 return nullptr;46 if (const auto *Bit = dyn_cast<BitInit>(&I))47 return Bit->getValue() ? 1 : 0;48 if (const auto *Bits = dyn_cast<BitsInit>(&I)) {49 json::Array Array;50 for (unsigned Idx = 0, E = Bits->getNumBits(); Idx < E; ++Idx)51 Array.push_back(translateInit(*Bits->getBit(Idx)));52 return std::move(Array);53 }54 if (const auto *Int = dyn_cast<IntInit>(&I))55 return Int->getValue();56 if (const auto *Str = dyn_cast<StringInit>(&I))57 return Str->getValue();58 if (const auto *List = dyn_cast<ListInit>(&I)) {59 json::Array Array;60 for (const auto *Val : *List)61 Array.push_back(translateInit(*Val));62 return std::move(Array);63 }64 65 // Init subclasses that we return as JSON objects containing a66 // 'kind' discriminator. For these, we also provide the same67 // translation back into TableGen input syntax that -print-records68 // would give.69 70 json::Object Obj;71 Obj["printable"] = I.getAsString();72 73 if (const auto *Def = dyn_cast<DefInit>(&I)) {74 Obj["kind"] = "def";75 Obj["def"] = Def->getDef()->getName();76 return std::move(Obj);77 }78 if (const auto *Var = dyn_cast<VarInit>(&I)) {79 Obj["kind"] = "var";80 Obj["var"] = Var->getName();81 return std::move(Obj);82 }83 if (const auto *VarBit = dyn_cast<VarBitInit>(&I)) {84 if (const auto *Var = dyn_cast<VarInit>(VarBit->getBitVar())) {85 Obj["kind"] = "varbit";86 Obj["var"] = Var->getName();87 Obj["index"] = VarBit->getBitNum();88 return std::move(Obj);89 }90 }91 if (const auto *Dag = dyn_cast<DagInit>(&I)) {92 Obj["kind"] = "dag";93 Obj["operator"] = translateInit(*Dag->getOperator());94 if (auto name = Dag->getName())95 Obj["name"] = name->getAsUnquotedString();96 json::Array Args;97 for (unsigned Idx = 0, E = Dag->getNumArgs(); Idx < E; ++Idx) {98 json::Array Arg;99 Arg.push_back(translateInit(*Dag->getArg(Idx)));100 if (const auto ArgName = Dag->getArgName(Idx))101 Arg.push_back(ArgName->getAsUnquotedString());102 else103 Arg.push_back(nullptr);104 Args.push_back(std::move(Arg));105 }106 Obj["args"] = std::move(Args);107 return std::move(Obj);108 }109 110 // Final fallback: anything that gets past here is simply given a111 // kind field of 'complex', and the only other field is the standard112 // 'printable' representation.113 assert(!I.isConcrete());114 Obj["kind"] = "complex";115 return std::move(Obj);116}117 118void JSONEmitter::run(raw_ostream &OS) {119 json::Object Root;120 121 Root["!tablegen_json_version"] = 1;122 123 // Prepare the arrays that will list the instances of every class.124 // We mostly fill those in by iterating over the superclasses of125 // each def, but we also want to ensure we store an empty list for a126 // class with no instances at all, so we do a preliminary iteration127 // over the classes, invoking std::map::operator[] to default-128 // construct the array for each one.129 std::map<std::string, json::Array> InstanceLists;130 for (const auto &[ClassName, ClassRec] : Records.getClasses())131 InstanceLists.emplace(ClassRec->getNameInitAsString(), json::Array());132 133 // Main iteration over the defs.134 for (const auto &[DefName, Def] : Records.getDefs()) {135 const std::string Name = Def->getNameInitAsString();136 137 json::Object Obj;138 json::Array Fields;139 140 for (const RecordVal &RV : Def->getValues()) {141 if (!Def->isTemplateArg(RV.getNameInit())) {142 auto Name = RV.getNameInitAsString();143 if (RV.isNonconcreteOK())144 Fields.push_back(Name);145 Obj[Name] = translateInit(*RV.getValue());146 }147 }148 149 Obj["!fields"] = std::move(Fields);150 151 json::Array SuperClasses;152 // Add this def to the instance list for each of its superclasses.153 for (const Record *SuperClass : Def->getSuperClasses()) {154 std::string SuperName = SuperClass->getNameInitAsString();155 SuperClasses.push_back(SuperName);156 InstanceLists[SuperName].push_back(Name);157 }158 159 Obj["!superclasses"] = std::move(SuperClasses);160 161 Obj["!name"] = Name;162 Obj["!anonymous"] = Def->isAnonymous();163 164 json::Array Locs;165 for (const SMLoc Loc : Def->getLoc())166 Locs.push_back(SrcMgr.getFormattedLocationNoOffset(Loc));167 Obj["!locs"] = std::move(Locs);168 169 Root[Name] = std::move(Obj);170 }171 172 // Make a JSON object from the std::map of instance lists.173 json::Object InstanceOf;174 for (auto &[ClassName, Instances] : InstanceLists)175 InstanceOf[ClassName] = std::move(Instances);176 Root["!instanceof"] = std::move(InstanceOf);177 178 // Done. Write the output.179 OS << json::Value(std::move(Root)) << "\n";180}181 182void llvm::EmitJSON(const RecordKeeper &RK, raw_ostream &OS) {183 JSONEmitter(RK).run(OS);184}185