[GitHub] [incubator-tvm] tqchen commented on a change in pull request #5932: [Frontend][Relay] Add Parser 2.0

[GitBox <gi...@apache.org>]

tqchen commented on a change in pull request #5932:
URL: https://github.com/apache/incubator-tvm/pull/5932#discussion_r449303920



##########
File path: src/parser/parser.cc
##########
@@ -0,0 +1,1103 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*!
+ * \file parser.cc
+ * \brief A parser for TVM IR.
+ */
+#include <tvm/ir/module.h>
+#include <tvm/relay/expr.h>
+#include <tvm/relay/function.h>
+#include <tvm/runtime/object.h>
+#include <tvm/runtime/registry.h>
+#include <tvm/node/reflection.h>
+
+#include <fstream>
+
+#include "./diagnostic.h"
+#include "./op_table.h"
+#include "./tokenizer.h"
+
+namespace tvm {
+namespace parser {
+
+using namespace relay;
+using Expr = relay::Expr;
+
+// adtConsDefnList: adtConsDefn (',' adtConsDefn)* ','? ;
+// adtConsDefn: constructorName ('(' typeExpr (',' typeExpr)* ')')? ;
+// matchClauseList: matchClause (',' matchClause)* ','? ;
+// matchClause: pattern '=>' ('{' expr '}' | expr) ;
+// // complete or incomplete match, respectively
+// matchType : 'match' | 'match?' ;
+
+// patternList: '(' pattern (',' pattern)* ')';
+// pattern
+//   : '_'                             # wildcardPattern
+//   | localVar (':' typeExpr)?        # varPattern
+//   | constructorName patternList?    # constructorPattern
+//   | patternList                     # tuplePattern
+//   ;
+
+struct GlobalFunc {
+  GlobalVar global;
+  Function function;
+  GlobalFunc() : global(), function() {}
+  GlobalFunc(GlobalVar global, Function function) : global(global), function(function) {}
+  GlobalFunc(const GlobalFunc& gfunc) {
+    this->global = gfunc.global;
+    this->function = gfunc.function;
+  }
+};
+
+struct Definitions {
+  std::vector<GlobalFunc> funcs;
+  std::vector<TypeData> types;
+};
+
+struct SemVer {
+  int major;
+  int minor;
+  int patch;
+};
+
+class MetaRefExpr;
+class MetaRefExprNode : public TempExprNode {
+ public:
+  std::string type_key;
+  uint64_t node_index;
+
+  void VisitAttrs(tvm::AttrVisitor* v) {}
+
+  Expr Realize() const final { return Expr(); }
+
+  static constexpr const char* _type_key = "relay.MetaRefExpr";
+  TVM_DECLARE_FINAL_OBJECT_INFO(MetaRefExprNode, TempExprNode);
+};
+
+class MetaRefExpr : public TempExpr {
+ public:
+  /*!
+   * \brief The constructor
+   * \param expr The original relay expression.
+   * \param kind The annotation kind.
+   */
+  TVM_DLL MetaRefExpr(std::string type_key, uint64_t node_index);
+
+  TVM_DEFINE_OBJECT_REF_METHODS(MetaRefExpr, TempExpr, MetaRefExprNode);
+};
+
+MetaRefExpr::MetaRefExpr(std::string type_key, uint64_t node_index) {
+  auto rnode = make_object<MetaRefExprNode>();
+  rnode->type_key = type_key;
+  rnode->node_index = node_index;
+  data_ = std::move(rnode);
+}
+
+template<typename T>
+struct Scope {
+  std::unordered_map<std::string, T> name_map;
+  Scope() : name_map() {}
+};
+
+template<typename T>
+struct ScopeStack {
+  std::vector<Scope<T>> scope_stack;
+
+  void Add(const std::string& name, const T& value) {
+    if (!this->scope_stack.size()) {
+      LOG(FATAL) << "internal issue";
+    }
+    this->scope_stack.back().name_map.insert({ name, value });
+  }
+
+  T Lookup(const std::string& name) {
+    for (auto scope = this->scope_stack.rbegin(); scope != this->scope_stack.rend(); scope++) {
+      auto it = scope->name_map.find(name);
+      if (it != scope->name_map.end()) {
+        return it->second;
+      }
+    }
+    return T();
+  }
+
+  void PushStack() {
+    this->scope_stack.push_back(Scope<T>());
+  }
+
+  void PopStack() {
+    this->scope_stack.pop_back();
+  }
+};
+
+template<typename T>
+struct InternTable {
+  std::unordered_map<std::string, T> table;
+  void Add(const std::string& name, const T& t) {
+    auto it = table.find(name);
+    if (it != table.end()) {
+      LOG(FATAL) << "duplicate name";
+    } else {
+      table.insert({ name, t});
+    }
+  }
+
+  T Get(const std::string& name) {
+    auto it = table.find(name);
+    if (it != table.end()) {
+      return it->second;
+    } else {
+      return T();
+    }
+  }
+};
+
+struct Parser {
+  /*! \brief The diagnostic context used for error reporting. */
+  DiagnosticContext diag_ctx;
+
+  /*! \brief The current position in the token stream. */
+  int pos;
+
+  /*! \brief The token stream for the parser. */
+  std::vector<Token> tokens;
+
+  /*! \brief The configured operator table. */
+  OperatorTable op_table;
+
+  /*! \brief Configure the whitespace mode, right now we ignore all whitespace. */
+  bool ignore_whitespace;
+
+  /*! \brief A global mapping for GlobalVar. */
+  InternTable<GlobalVar> global_names;
+
+  /*! \brief A global mapping for type definitions. */
+  InternTable<GlobalTypeVar> type_names;
+
+  /*! \brief A mapping from graph variable to expression, i.e., `%0 = expr`. */
+  std::unordered_map<int, Expr> graph_ctx;
+
+  /*! \brief The set of type scopes used for generics. */
+  ScopeStack<TypeVar> type_scopes;
+
+  /*! \brief The set of expression scopes used for lexical scope. */
+  ScopeStack<Var> expr_scopes;
+
+  Parser(std::vector<Token> tokens, OperatorTable op_table, Source source)
+      : diag_ctx(source), pos(0), tokens(tokens), op_table(op_table), ignore_whitespace(true) {}
+
+  void DisplayNextN(int n) {
+    std::cout << "remaining tokens: " << std::endl;
+    auto bound = std::min(pos + n, (int)tokens.size());
+    for (int i = 0; i < bound - pos; i++) {
+      std::cout << tokens[pos + i] << std::endl;
+    }
+  }
+
+  Token Peek() {
+    // For now we ignore all whitespace tokens and comments.
+    // We can tweak this behavior later to enable white space sensitivity in the parser.
+    while (pos < tokens.size() &&
+           ignore_whitespace && (tokens.at(pos)->token_type == TokenType::Whitespace ||
+                                 tokens.at(pos)->token_type == TokenType::Newline ||
+                                 tokens.at(pos)->token_type == TokenType::LineComment ||
+                                 tokens.at(pos)->token_type == TokenType::Comment)) {
+      // std::cout << "pos: " << pos << std::endl;
+      // std::cout << "tokens: " << tokens.size() << std::endl;
+      pos++;
+    }
+
+    if (pos < tokens.size()) {
+      return Token(this->tokens.at(pos));
+    } else {
+      return Token::Null();
+    }
+  }
+
+  // Allow lookahead into the token stream.
+  Token Lookahead(int n) {
+    CHECK_LE(1, n)
+      << "lookahead by > 1 is invalid";
+
+    auto old_pos = pos;
+    for (int i = 0; i < n - 1; i++) {
+      Peek();
+      pos++;
+    }
+
+    auto tok = Peek();
+    pos = old_pos;
+    return tok;
+  }
+
+  void Consume(const TokenType& token) {
+    if (tokens[pos]->token_type != token) {
+      std::string message =  "expected a " + Pretty(token) + " found " + Pretty(Peek()->token_type);
+      this->diag_ctx.Emit({tokens[pos]->line, tokens[pos]->column, message});
+      this->diag_ctx.Render();
+    }
+    pos++;
+  }
+
+  Token Match(const TokenType& token_type) {
+    auto tok = Peek();
+    Consume(token_type);
+    return tok;
+  }
+
+  bool WhenMatch(const TokenType& token_type) {
+    if (Peek()->token_type == token_type) {
+      Consume(token_type);
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  void AddGraphBinding(const Token& token, const Expr& expr) {
+    auto graph_no = token.ToNumber();
+    this->graph_ctx.insert({graph_no, expr});
+  }
+
+  Expr LookupGraphBinding(const Token& token) {
+    auto graph_no = token.ToNumber();
+    return this->graph_ctx.at(graph_no);
+  }
+
+  Var BindVar(const std::string& name, const relay::Type& type_annotation) {
+    auto var = Var(name, type_annotation);
+    this->expr_scopes.Add(name, var);
+    return var;
+  }
+
+  TypeVar BindTypeVar(const std::string& name, const TypeKind type_kind) {
+    auto type_var = TypeVar(name, type_kind);
+    this->type_scopes.Add(name, type_var);
+    return type_var;
+  }
+
+  Var LookupLocal(const Token& local) {
+    auto var = this->expr_scopes.Lookup(local.ToString());
+    if (!var.defined()) {
+      diag_ctx.Emit({ local->line, local->column, "this local variable has not been previously declared"});
+    }
+    return var;
+  }
+
+  TypeVar LookupTypeVar(const Token& ident) {
+    auto var = this->type_scopes.Lookup(ident.ToString());
+    if (!var.defined()) {
+      diag_ctx.Emit({ ident->line, ident->column, "this type variable has not been previously declared anywhere, perhaps a typo?"});
+    }
+    return var;
+  }
+
+  void PushScope() {
+    this->expr_scopes.PushStack();
+  }
+
+  void PopScopes(int n) {
+    for (int i = 0; i < n; i++) {
+      this->expr_scopes.PopStack();
+    }
+  }
+
+  void PushTypeScope() {
+    this->type_scopes.PushStack();
+  }
+
+  void PopTypeScopes(int n) {
+    for (int i = 0; i < n; i++) {
+      this->type_scopes.PopStack();
+    }
+  }
+
+  NDArray NumberToNDArray(const Token& token) {
+    if (token->token_type == TokenType::Integer) {
+      DLContext ctx({.device_type = DLDeviceType::kDLCPU, .device_id = 0});
+      auto dtype = String2DLDataType("int32");
+      auto data = NDArray::Empty({}, dtype, ctx);
+      auto array = reinterpret_cast<int32_t*>(data->data);
+      // revisit this, literal node issue.
+      int64_t value = Downcast<tvm::Integer>(token->data);
+      array[0] = (int32_t)value;
+      return data;
+    } else if (token->token_type == TokenType::Float) {
+      DLContext ctx({.device_type = DLDeviceType::kDLCPU, .device_id = 0});
+      auto dtype = String2DLDataType("float32");
+      auto data = NDArray::Empty({}, dtype, ctx);
+      auto array = reinterpret_cast<float*>(data->data);
+      // revisit this, literal node issue.
+      float value = Downcast<tvm::FloatImm>(token->data)->value;
+      array[0] = value;
+      return data;
+    } else {
+      throw "foo";
+    }
+  }
+
+  NDArray BooleanToNDarray(bool value) {
+    DLContext ctx({.device_type = DLDeviceType::kDLCPU, .device_id = 0});
+    auto dtype = String2DLDataType("bool");
+    auto data = NDArray::Empty({}, dtype, ctx);
+    auto array = reinterpret_cast<bool*>(data->data);
+    array[0] = value;
+    return data;
+  }
+
+  [[noreturn]] void ParseError(const Token& token, const std::string& msg) {
+    throw std::runtime_error(msg);
+  }
+
+  IRModule ParseModule() {
+    // Parse the semver header at the top of the module.
+    auto _version = ParseSemVer();
+    // Parse the definitions.
+    auto defs = ParseDefinitions();
+    // Parse the metadata section at the end.
+    auto metadata = ParseMetadata();
+    Match(TokenType::EndOfFile);
+    Map<tvm::GlobalVar, BaseFunc> funcs;
+    Map<tvm::GlobalTypeVar, TypeData> types;
+
+    for (auto func : defs.funcs) {
+      funcs.Set(func.global, func.function);
+    }
+
+    for (auto type_def : defs.types) {
+      types.Set(type_def->header, type_def);
+    }
+
+    return IRModule(funcs, types);
+  }
+
+  SemVer ParseSemVer() {
+    // Consume(TokenType::Unknown);
+    return SemVer{.major = 0, .minor = 0, .patch = 0};
+  }
+
+  Definitions ParseDefinitions() {
+    Definitions defs;
+
+    while (true) {
+     auto next = Peek();
+     switch (next->token_type) {
+        case TokenType::Defn: {
+          Consume(TokenType::Defn);
+          auto global_name = Match(TokenType::Global).ToString();
+          auto global = GlobalVar(global_name);
+          global_names.Add(global_name, global);
+          auto func = ParseFunctionDef();
+          defs.funcs.push_back(GlobalFunc(global, func));
+          continue;
+        }
+        case TokenType::TypeDef: {
+          defs.types.push_back(ParseTypeDef());
+          continue;
+        }
+        default:
+          return defs;
+      }
+    }
+  }
+
+  TypeData ParseTypeDef() {
+    // Match the `type` keyword.
+    Match(TokenType::TypeDef);
+    // Parse the type's identifier.
+    auto type_id = Match(TokenType::Identifier).ToString();
+    auto type_global = tvm::GlobalTypeVar(type_id, TypeKind::kTypeData);
+    type_names.Add(type_id, type_global);
+
+    Array<TypeVar> generics;
+
+    bool should_pop = false;
+    if (Peek()->token_type == TokenType::LSquare) {
+      // If we have generics we need to add a type scope.
+      PushTypeScope();
+      should_pop = true;
+      generics = ParseSequence<TypeVar>(TokenType::LSquare, TokenType::Comma, TokenType::RSquare, [&]() {
+        auto type_var_name = Match(TokenType::Identifier).ToString();
+        return BindTypeVar(type_var_name, TypeKind::kType);
+      });
+    }
+
+    // Parse the list of constructors.
+    auto ctors = ParseSequence<tvm::Constructor>(TokenType::LCurly, TokenType::Comma, TokenType::RCurly, [&]() {
+      // First match the name of the constructor.
+      auto ctor = Match(TokenType::Identifier).ToString();
+      // Match the optional field list.
+      if (Peek()->token_type != TokenType::OpenParen) {
+        return tvm::Constructor(ctor, {}, type_global);
+      } else {
+        auto arg_types = ParseSequence<Type>(TokenType::OpenParen, TokenType::Comma, TokenType::CloseParen, [&]() {
+          return ParseType();
+        });
+        return tvm::Constructor(ctor, arg_types, type_global);
+      }
+    });
+
+    // Now pop the type scope.
+    if (should_pop) {
+      PopTypeScopes(1);
+    }
+
+    return TypeData(type_global, generics, ctors);
+  }
+
+  template <typename R>
+  R Bracket(TokenType open, TokenType close, std::function<R()> parser) {

Review comment:
       the template F is the most efficient way if you want it to be inlined




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