src/emscripten-optimizer/parser.cpp

/*
 * Copyright 2015 WebAssembly Community Group participants
 *
 * Licensed 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.
 */

#include <unordered_map>

#include "parser.h"

namespace cashew {

// common strings

IString TOPLEVEL("toplevel");
IString DEFUN("defun");
IString BLOCK("block");
IString VAR("var");
IString CONST("const");
IString CONDITIONAL("conditional");
IString BINARY("binary");
IString RETURN("return");
IString IF("if");
IString ELSE("else");
IString WHILE("while");
IString DO("do");
IString FOR("for");
IString SEQ("seq");
IString SUB("sub");
IString CALL("call");
IString LABEL("label");
IString BREAK("break");
IString CONTINUE("continue");
IString SWITCH("switch");
IString STRING("string");
IString TRY("try");
IString INF("inf");
IString NaN("nan");
IString LLVM_CTTZ_I32("_llvm_cttz_i32");
IString UDIVMODDI4("___udivmoddi4");
IString UNARY_PREFIX("unary-prefix");
IString UNARY_POSTFIX("unary-postfix");
IString MATH_FROUND("Math_fround");
IString MATH_CLZ32("Math_clz32");
IString INT64("i64");
IString INT64_CONST("i64_const");
IString SIMD_FLOAT32X4("SIMD_Float32x4");
IString SIMD_FLOAT64X2("SIMD_Float64x2");
IString SIMD_INT8X16("SIMD_Int8x16");
IString SIMD_INT16X8("SIMD_Int16x8");
IString SIMD_INT32X4("SIMD_Int32x4");
IString PLUS("+");
IString MINUS("-");
IString OR("|");
IString AND("&");
IString XOR("^");
IString L_NOT("!");
IString B_NOT("~");
IString LT("<");
IString GE(">=");
IString LE("<=");
IString GT(">");
IString EQ("==");
IString NE("!=");
IString DIV("/");
IString MOD("%");
IString MUL("*");
IString RSHIFT(">>");
IString LSHIFT("<<");
IString TRSHIFT(">>>");
IString HEAP8("HEAP8");
IString HEAP16("HEAP16");
IString HEAP32("HEAP32");
IString HEAPF32("HEAPF32");
IString HEAPU8("HEAPU8");
IString HEAPU16("HEAPU16");
IString HEAPU32("HEAPU32");
IString HEAPF64("HEAPF64");
IString F0("f0");
IString EMPTY("");
IString FUNCTION("function");
IString OPEN_PAREN("(");
IString OPEN_BRACE("[");
IString OPEN_CURLY("{");
IString CLOSE_CURLY("}");
IString COMMA(",");
IString QUESTION("?");
IString COLON(":");
IString CASE("case");
IString DEFAULT("default");
IString DOT("dot");
IString PERIOD(".");
IString NEW("new");
IString ARRAY("array");
IString OBJECT("object");
IString THROW("throw");
IString SET("=");
IString ATOMICS("Atomics");
IString COMPARE_EXCHANGE("compareExchange");
IString LOAD("load");
IString STORE("store");
IString GETTER("get");
IString SETTER("set");

const char *OPERATOR_INITS = "+-*/%<>&^|~=!,?:.", *SEPARATORS = "([;{}";

int MAX_OPERATOR_SIZE = 3;

std::vector<OperatorClass> operatorClasses;

static std::vector<std::unordered_map<IString, int>>
  precedences; // op, type => prec

struct Init {
  Init() {
    // operators, rtl, type
    operatorClasses.emplace_back(".", false, OperatorClass::Binary);
    operatorClasses.emplace_back("! ~ + -", true, OperatorClass::Prefix);
    operatorClasses.emplace_back("* / %", false, OperatorClass::Binary);
    operatorClasses.emplace_back("+ -", false, OperatorClass::Binary);
    operatorClasses.emplace_back("<< >> >>>", false, OperatorClass::Binary);
    operatorClasses.emplace_back("< <= > >=", false, OperatorClass::Binary);
    operatorClasses.emplace_back("== !=", false, OperatorClass::Binary);
    operatorClasses.emplace_back("&", false, OperatorClass::Binary);
    operatorClasses.emplace_back("^", false, OperatorClass::Binary);
    operatorClasses.emplace_back("|", false, OperatorClass::Binary);
    operatorClasses.emplace_back("? :", true, OperatorClass::Tertiary);
    operatorClasses.emplace_back("=", true, OperatorClass::Binary);
    operatorClasses.emplace_back(",", true, OperatorClass::Binary);

    precedences.resize(OperatorClass::Tertiary + 1);

    for (size_t prec = 0; prec < operatorClasses.size(); prec++) {
      for (auto curr : operatorClasses[prec].ops) {
        precedences[operatorClasses[prec].type][curr] = prec;
      }
    }
  }
};

Init init;

int OperatorClass::getPrecedence(Type type, IString op) {
  return precedences[type][op];
}

bool OperatorClass::getRtl(int prec) { return operatorClasses[prec].rtl; }

bool isIdentInit(char x) {
  return (x >= 'a' && x <= 'z') || (x >= 'A' && x <= 'Z') || x == '_' ||
         x == '$';
}
bool isIdentPart(char x) { return isIdentInit(x) || (x >= '0' && x <= '9'); }

} // namespace cashew