Rewrite parser as recursive descent (#591)

* Remove Bison dependency
* Remove pre-generated parser files
* Rename build config from no-re2c-bison to no-re2c
* Add a simple make_unique implementation
* Move handling of module bindings into ir.cc
* Simplify lexer
  - Remove lookahead, the parser handles this now
  - Unify Token/LexerToken, it only contains terminal values now
  - Refactor setting token type and value into one function (e.g.
    LITERAL, RETURN => RETURN_LITERAL)
* New Parser
  - Uses two tokens of lookahead (use Peek(0) or Peek(1))
  - Consume() consumes one token of any kind
  - Match(t) consumes the current token if it matches
  - PeekMatch(t) returns true iff the token matches, but doesn't consume
  - Basic error synchronization; plenty of room for improvement here

1 files changed, 5 insertions, 109 deletions

diff --git a/src/wast-parser-lexer-shared.h b/src/wast-parser-lexer-shared.h
index b5774d58..f3b4607a 100644
--- a/src/wast-parser-lexer-shared.h
+++ b/src/wast-parser-lexer-shared.h
@@ -18,120 +18,16 @@
 #define WABT_WAST_PARSER_LEXER_SHARED_H_
 
 #include <cstdarg>
-#include <memory>
-
-#include "common.h"
-#include "error-handler.h"
-#include "ir.h"
-#include "literal.h"
-#include "wast-parser.h"
-
-#define WABT_WAST_PARSER_STYPE Token
-#define WABT_WAST_PARSER_LTYPE Location
-#define YYSTYPE WABT_WAST_PARSER_STYPE
-#define YYLTYPE WABT_WAST_PARSER_LTYPE
 
 namespace wabt {
 
-// Terminal types are C-style structs so they don't need to be allocated. Any
-// string memory used by terminals is shared with the lexer and does not need
-// to be dellocated.
-
-struct StringTerminal {
-  const char* data;
-  size_t size;
-
-  // Helper functions.
-  std::string to_string() const { return std::string(data, size); }
-  string_view to_string_view() const { return string_view(data, size); }
-};
-
-struct LiteralTerminal {
-  LiteralType type;
-  StringTerminal text;
-};
-
-struct Literal {
-  explicit Literal(LiteralTerminal terminal)
-      : type(terminal.type), text(terminal.text.to_string()) {}
-
-  LiteralType type;
-  std::string text;
-};
-
-typedef std::vector<std::string> TextVector;
-
-union Token {
-  // Terminals
-  StringTerminal t_text;
-  Type t_type;
-  Opcode t_opcode;
-  LiteralTerminal t_literal;
-
-  Token() {}
-
-  // Non-terminals
-  // Some of these use pointers to keep the size of Token down; copying the
-  // tokens is a hotspot when parsing large files.
-  Action* action;
-  Block* block;
-  Catch* catch_;
-  Command* command;
-  CommandPtrVector* commands;
-  Const const_;
-  ConstVector* consts;
-  DataSegment* data_segment;
-  ElemSegment* elem_segment;
-  Exception* exception;
-  Export* export_;
-  Expr* expr;
-  ExprList* expr_list;
-  Func* func;
-  FuncSignature* func_sig;
-  FuncType* func_type;
-  Global* global;
-  Import* import;
-  Limits limits;
-  Literal* literal;
-  Memory* memory;
-  Module* module;
-  ModuleField* module_field;
-  ModuleFieldList* module_fields;
-  ScriptModule* script_module;
-  Script* script;
-  std::string* string;
-  Table* table;
-  TextVector* texts;
-  TryExpr* try_expr;
-  TypeVector* types;
-  uint32_t u32;
-  uint64_t u64;
-  Var* var;
-  VarVector* vars;
-};
-
-struct WastParser {
-  Script* script;
-  ErrorHandler* error_handler;
-  int errors;
-  /* Cached pointers to reallocated parser buffers, so they don't leak. */
-  int16_t* yyssa;
-  YYSTYPE* yyvsa;
-  YYLTYPE* yylsa;
-  WastParseOptions* options;
-};
+class ErrorHandler;
+struct Location;
+class WastLexer;
 
-int WastLexerLex(union Token*,
-                 struct Location*,
-                 WastLexer*,
-                 struct WastParser*);
-void WABT_PRINTF_FORMAT(4, 5) WastParserError(struct Location*,
-                                              WastLexer*,
-                                              struct WastParser*,
-                                              const char*,
-                                              ...);
+// TODO(binji): Move this somewhere else.
 void WastFormatError(ErrorHandler*,
-                     const struct Location*,
+                     const Location*,
                      WastLexer*,
                      const char* format,
                      va_list);