clang-tools-extra/pseudo/unittests/LRTableTest.cpp

   1 //===--- LRTableTest.cpp - ---------------------------------------*- 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 #include "clang-pseudo/grammar/LRTable.h"
  10 #include "clang-pseudo/grammar/Grammar.h"
  11 #include "clang/Basic/TokenKinds.h"
  12 #include "llvm/Testing/Support/SupportHelpers.h"
  13 #include "gmock/gmock.h"
  14 #include "gtest/gtest.h"
  15 #include <vector>
  16
  17 namespace clang {
  18 namespace pseudo {
  19 namespace {
  20
  21 using llvm::ValueIs;
  22 using testing::ElementsAre;
  23 using StateID = LRTable::StateID;
  24
  25 TEST(LRTable, Builder) {
  26   std::vector<std::string> GrammarDiags;
  27   Grammar G = Grammar::parseBNF(R"bnf(
  28     _ := expr            # rule 0
  29     expr := term         # rule 1
  30     expr := expr + term  # rule 2
  31     term := IDENTIFIER   # rule 3
  32   )bnf",
  33                                 GrammarDiags);
  34   EXPECT_THAT(GrammarDiags, testing::IsEmpty());
  35
  36   SymbolID Term = *G.findNonterminal("term");
  37   SymbolID Eof = tokenSymbol(tok::eof);
  38   SymbolID Identifier = tokenSymbol(tok::identifier);
  39   SymbolID Plus = tokenSymbol(tok::plus);
  40
  41   LRTable::Builder B(G);
  42   //           eof  IDENT   term
  43   // +-------+----+-------+------+
  44   // |state0 |    | s0    |      |
  45   // |state1 |    |       | g3   |
  46   // |state2 |    |       |      |
  47   // +-------+----+-------+------+-------
  48   B.Transition[{StateID{0}, Identifier}] = StateID{0};
  49   B.Transition[{StateID{1}, Term}] = StateID{3};
  50   B.Reduce[StateID{0}].insert(RuleID{0});
  51   B.Reduce[StateID{1}].insert(RuleID{2});
  52   B.Reduce[StateID{2}].insert(RuleID{1});
  53   LRTable T = std::move(B).build();
  54
  55   EXPECT_EQ(T.getShiftState(0, Eof), llvm::None);
  56   EXPECT_THAT(T.getShiftState(0, Identifier), ValueIs(0));
  57   EXPECT_THAT(T.getReduceRules(0), ElementsAre(0));
  58
  59   EXPECT_EQ(T.getShiftState(1, Eof), llvm::None);
  60   EXPECT_EQ(T.getShiftState(1, Identifier), llvm::None);
  61   EXPECT_THAT(T.getGoToState(1, Term), ValueIs(3));
  62   EXPECT_THAT(T.getReduceRules(1), ElementsAre(2));
  63
  64   // Verify the behaivor for other non-available-actions terminals.
  65   SymbolID Int = tokenSymbol(tok::kw_int);
  66   EXPECT_EQ(T.getShiftState(2, Int), llvm::None);
  67
  68   // Check follow sets.
  69   EXPECT_TRUE(T.canFollow(Term, Plus));
  70   EXPECT_TRUE(T.canFollow(Term, Eof));
  71   EXPECT_FALSE(T.canFollow(Term, Int));
  72 }
  73
  74 } // namespace
  75 } // namespace pseudo
  76 } // namespace clang