llvm-project/clang-tools-extra/pseudo/lib/LRTable.cpp

125 lines
4.8 KiB
C++

//===--- LRTable.cpp - Parsing table for LR parsers --------------*- C++-*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "clang-pseudo/LRTable.h"
#include "clang-pseudo/Grammar.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/raw_ostream.h"
namespace clang {
namespace pseudo {
llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const LRTable::Action &A) {
switch (A.kind()) {
case LRTable::Action::Shift:
return OS << llvm::formatv("shift state {0}", A.getShiftState());
case LRTable::Action::Reduce:
return OS << llvm::formatv("reduce by rule {0}", A.getReduceRule());
case LRTable::Action::GoTo:
return OS << llvm::formatv("go to state {0}", A.getGoToState());
case LRTable::Action::Accept:
return OS << "acc";
case LRTable::Action::Sentinel:
llvm_unreachable("unexpected Sentinel action kind!");
}
llvm_unreachable("unexpected action kind!");
}
std::string LRTable::dumpStatistics() const {
StateID NumOfStates = 0;
for (StateID It : States)
NumOfStates = std::max(It, NumOfStates);
return llvm::formatv(R"(
Statistics of the LR parsing table:
number of states: {0}
number of actions: {1}
size of the table (bytes): {2}
)",
NumOfStates, Actions.size(), bytes())
.str();
}
std::string LRTable::dumpForTests(const Grammar &G) const {
std::string Result;
llvm::raw_string_ostream OS(Result);
StateID MaxState = 0;
for (StateID It : States)
MaxState = std::max(MaxState, It);
OS << "LRTable:\n";
for (StateID S = 0; S <= MaxState; ++S) {
OS << llvm::formatv("State {0}\n", S);
for (uint16_t Terminal = 0; Terminal < NumTerminals; ++Terminal) {
SymbolID TokID = tokenSymbol(static_cast<tok::TokenKind>(Terminal));
for (auto A : find(S, TokID)) {
if (A.kind() == LRTable::Action::Shift)
OS.indent(4) << llvm::formatv("'{0}': shift state {1}\n",
G.symbolName(TokID), A.getShiftState());
else if (A.kind() == LRTable::Action::Reduce)
OS.indent(4) << llvm::formatv("'{0}': reduce by rule {1} '{2}'\n",
G.symbolName(TokID), A.getReduceRule(),
G.dumpRule(A.getReduceRule()));
else if (A.kind() == LRTable::Action::Accept)
OS.indent(4) << llvm::formatv("'{0}': accept\n", G.symbolName(TokID));
}
}
for (SymbolID NontermID = 0; NontermID < G.table().Nonterminals.size();
++NontermID) {
if (find(S, NontermID).empty())
continue;
OS.indent(4) << llvm::formatv("'{0}': go to state {1}\n",
G.symbolName(NontermID),
getGoToState(S, NontermID));
}
}
return OS.str();
}
llvm::ArrayRef<LRTable::Action> LRTable::getActions(StateID State,
SymbolID Terminal) const {
assert(pseudo::isToken(Terminal) && "expect terminal symbol!");
return find(State, Terminal);
}
LRTable::StateID LRTable::getGoToState(StateID State,
SymbolID Nonterminal) const {
assert(pseudo::isNonterminal(Nonterminal) && "expected nonterminal symbol!");
auto Result = find(State, Nonterminal);
assert(Result.size() == 1 && Result.front().kind() == Action::GoTo);
return Result.front().getGoToState();
}
llvm::ArrayRef<LRTable::Action> LRTable::find(StateID Src, SymbolID ID) const {
size_t Idx = isToken(ID) ? symbolToToken(ID) : ID;
assert(isToken(ID) ? Idx + 1 < TerminalOffset.size()
: Idx + 1 < NontermOffset.size());
std::pair<size_t, size_t> TargetStateRange =
isToken(ID) ? std::make_pair(TerminalOffset[Idx], TerminalOffset[Idx + 1])
: std::make_pair(NontermOffset[Idx], NontermOffset[Idx + 1]);
auto TargetedStates =
llvm::makeArrayRef(States.data() + TargetStateRange.first,
States.data() + TargetStateRange.second);
assert(llvm::is_sorted(TargetedStates) &&
"subrange of the StateIdx should be sorted!");
const LRTable::StateID *Start = llvm::partition_point(
TargetedStates, [&Src](LRTable::StateID S) { return S < Src; });
if (Start == TargetedStates.end())
return {};
const LRTable::StateID *End = Start;
while (End != TargetedStates.end() && *End == Src)
++End;
return llvm::makeArrayRef(&Actions[Start - States.data()],
/*length=*/End - Start);
}
} // namespace pseudo
} // namespace clang