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//===-- Arena.cpp ---------------------------------------------------------===//
//
// 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/Analysis/FlowSensitive/Arena.h"
#include "clang/Analysis/FlowSensitive/Formula.h"
#include "clang/Analysis/FlowSensitive/Value.h"
#include "llvm/Support/Error.h"
#include <string>
namespace clang::dataflow {
static std::pair<const Formula *, const Formula *>
canonicalFormulaPair(const Formula &LHS, const Formula &RHS) {
auto Res = std::make_pair(&LHS, &RHS);
if (&RHS < &LHS) // FIXME: use a deterministic order instead
std::swap(Res.first, Res.second);
return Res;
}
template <class Key, class ComputeFunc>
const Formula &cached(llvm::DenseMap<Key, const Formula *> &Cache, Key K,
ComputeFunc &&Compute) {
auto [It, Inserted] = Cache.try_emplace(std::forward<Key>(K));
if (Inserted)
It->second = Compute();
return *It->second;
}
const Formula &Arena::makeAtomRef(Atom A) {
return cached(AtomRefs, A, [&] {
return &Formula::create(Alloc, Formula::AtomRef, {},
static_cast<unsigned>(A));
});
}
const Formula &Arena::makeAnd(const Formula &LHS, const Formula &RHS) {
return cached(Ands, canonicalFormulaPair(LHS, RHS), [&] {
if (&LHS == &RHS)
return &LHS;
if (LHS.kind() == Formula::Literal)
return LHS.literal() ? &RHS : &LHS;
if (RHS.kind() == Formula::Literal)
return RHS.literal() ? &LHS : &RHS;
return &Formula::create(Alloc, Formula::And, {&LHS, &RHS});
});
}
const Formula &Arena::makeOr(const Formula &LHS, const Formula &RHS) {
return cached(Ors, canonicalFormulaPair(LHS, RHS), [&] {
if (&LHS == &RHS)
return &LHS;
if (LHS.kind() == Formula::Literal)
return LHS.literal() ? &LHS : &RHS;
if (RHS.kind() == Formula::Literal)
return RHS.literal() ? &RHS : &LHS;
return &Formula::create(Alloc, Formula::Or, {&LHS, &RHS});
});
}
const Formula &Arena::makeNot(const Formula &Val) {
return cached(Nots, &Val, [&] {
if (Val.kind() == Formula::Not)
return Val.operands()[0];
if (Val.kind() == Formula::Literal)
return &makeLiteral(!Val.literal());
return &Formula::create(Alloc, Formula::Not, {&Val});
});
}
const Formula &Arena::makeImplies(const Formula &LHS, const Formula &RHS) {
return cached(Implies, std::make_pair(&LHS, &RHS), [&] {
if (&LHS == &RHS)
return &makeLiteral(true);
if (LHS.kind() == Formula::Literal)
return LHS.literal() ? &RHS : &makeLiteral(true);
if (RHS.kind() == Formula::Literal)
return RHS.literal() ? &RHS : &makeNot(LHS);
return &Formula::create(Alloc, Formula::Implies, {&LHS, &RHS});
});
}
const Formula &Arena::makeEquals(const Formula &LHS, const Formula &RHS) {
return cached(Equals, canonicalFormulaPair(LHS, RHS), [&] {
if (&LHS == &RHS)
return &makeLiteral(true);
if (LHS.kind() == Formula::Literal)
return LHS.literal() ? &RHS : &makeNot(RHS);
if (RHS.kind() == Formula::Literal)
return RHS.literal() ? &LHS : &makeNot(LHS);
return &Formula::create(Alloc, Formula::Equal, {&LHS, &RHS});
});
}
IntegerValue &Arena::makeIntLiteral(llvm::APInt Value) {
auto [It, Inserted] = IntegerLiterals.try_emplace(Value, nullptr);
if (Inserted)
It->second = &create<IntegerValue>();
return *It->second;
}
BoolValue &Arena::makeBoolValue(const Formula &F) {
auto [It, Inserted] = FormulaValues.try_emplace(&F);
if (Inserted)
It->second = (F.kind() == Formula::AtomRef)
? (BoolValue *)&create<AtomicBoolValue>(F)
: &create<FormulaBoolValue>(F);
return *It->second;
}
namespace {
const Formula *parse(Arena &A, llvm::StringRef &In) {
auto EatSpaces = [&] { In = In.ltrim(' '); };
EatSpaces();
if (In.consume_front("!")) {
if (auto *Arg = parse(A, In))
return &A.makeNot(*Arg);
return nullptr;
}
if (In.consume_front("(")) {
auto *Arg1 = parse(A, In);
if (!Arg1)
return nullptr;
EatSpaces();
decltype(&Arena::makeOr) Op;
if (In.consume_front("|"))
Op = &Arena::makeOr;
else if (In.consume_front("&"))
Op = &Arena::makeAnd;
else if (In.consume_front("=>"))
Op = &Arena::makeImplies;
else if (In.consume_front("="))
Op = &Arena::makeEquals;
else
return nullptr;
auto *Arg2 = parse(A, In);
if (!Arg2)
return nullptr;
EatSpaces();
if (!In.consume_front(")"))
return nullptr;
return &(A.*Op)(*Arg1, *Arg2);
}
// For now, only support unnamed variables V0, V1 etc.
// FIXME: parse e.g. "X" by allocating an atom and storing a name somewhere.
if (In.consume_front("V")) {
std::underlying_type_t<Atom> At;
if (In.consumeInteger(10, At))
return nullptr;
return &A.makeAtomRef(static_cast<Atom>(At));
}
if (In.consume_front("true"))
return &A.makeLiteral(true);
if (In.consume_front("false"))
return &A.makeLiteral(false);
return nullptr;
}
class FormulaParseError : public llvm::ErrorInfo<FormulaParseError> {
std::string Formula;
unsigned Offset;
public:
static char ID;
FormulaParseError(llvm::StringRef Formula, unsigned Offset)
: Formula(Formula), Offset(Offset) {}
void log(raw_ostream &OS) const override {
OS << "bad formula at offset " << Offset << "\n";
OS << Formula << "\n";
OS.indent(Offset) << "^";
}
std::error_code convertToErrorCode() const override {
return std::make_error_code(std::errc::invalid_argument);
}
};
char FormulaParseError::ID = 0;
} // namespace
llvm::Expected<const Formula &> Arena::parseFormula(llvm::StringRef In) {
llvm::StringRef Rest = In;
auto *Result = parse(*this, Rest);
if (!Result) // parse() hit something unparseable
return llvm::make_error<FormulaParseError>(In, In.size() - Rest.size());
Rest = Rest.ltrim();
if (!Rest.empty()) // parse didn't consume all the input
return llvm::make_error<FormulaParseError>(In, In.size() - Rest.size());
return *Result;
}
} // namespace clang::dataflow
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