DebugSupport.cpp

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//===- DebugSupport.cpp -----------------------------------------*- 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
//
//===----------------------------------------------------------------------===//
//
//  This file defines functions which generate more readable forms of data
//  structures used in the dataflow analyses, for debugging purposes.
//
//===----------------------------------------------------------------------===//
 
#include <utility>
 
#include "clang/Analysis/FlowSensitive/DebugSupport.h"
#include "clang/Analysis/FlowSensitive/Solver.h"
#include "clang/Analysis/FlowSensitive/Value.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormatAdapters.h"
#include "llvm/Support/FormatCommon.h"
#include "llvm/Support/FormatVariadic.h"
 
namespace clang {
namespace dataflow {
 
using llvm::AlignStyle;
using llvm::fmt_pad;
using llvm::formatv;
 
llvm::StringRef debugString(Value::Kind Kind) {
  switch (Kind) {
  case Value::Kind::Integer:
    return "Integer";
  case Value::Kind::Reference:
    return "Reference";
  case Value::Kind::Pointer:
    return "Pointer";
  case Value::Kind::Struct:
    return "Struct";
  case Value::Kind::AtomicBool:
    return "AtomicBool";
  case Value::Kind::Conjunction:
    return "Conjunction";
  case Value::Kind::Disjunction:
    return "Disjunction";
  case Value::Kind::Negation:
    return "Negation";
  case Value::Kind::Implication:
    return "Implication";
  case Value::Kind::Biconditional:
    return "Biconditional";
  }
  llvm_unreachable("Unhandled value kind");
}
 
llvm::StringRef debugString(Solver::Result::Assignment Assignment) {
  switch (Assignment) {
  case Solver::Result::Assignment::AssignedFalse:
    return "False";
  case Solver::Result::Assignment::AssignedTrue:
    return "True";
  }
  llvm_unreachable("Booleans can only be assigned true/false");
}
 
llvm::StringRef debugString(Solver::Result::Status Status) {
  switch (Status) {
  case Solver::Result::Status::Satisfiable:
    return "Satisfiable";
  case Solver::Result::Status::Unsatisfiable:
    return "Unsatisfiable";
  case Solver::Result::Status::TimedOut:
    return "TimedOut";
  }
  llvm_unreachable("Unhandled SAT check result status");
}
 
namespace {
 
class DebugStringGenerator {
public:
  explicit DebugStringGenerator(
      llvm::DenseMap<const AtomicBoolValue *, std::string> AtomNamesArg)
      : Counter(0), AtomNames(std::move(AtomNamesArg)) {
#ifndef NDEBUG
    llvm::StringSet<> Names;
    for (auto &N : AtomNames) {
      assert(Names.insert(N.second).second &&
             "The same name must not assigned to different atoms");
    }
#endif
  }
 
  /// Returns a string representation of a boolean value `B`.
  std::string debugString(const BoolValue &B, size_t Depth = 0) {
    std::string S;
    switch (B.getKind()) {
    case Value::Kind::AtomicBool: {
      S = getAtomName(&cast<AtomicBoolValue>(B));
      break;
    }
    case Value::Kind::Conjunction: {
      auto &C = cast<ConjunctionValue>(B);
      auto L = debugString(C.getLeftSubValue(), Depth + 1);
      auto R = debugString(C.getRightSubValue(), Depth + 1);
      S = formatv("(and\n{0}\n{1})", L, R);
      break;
    }
    case Value::Kind::Disjunction: {
      auto &D = cast<DisjunctionValue>(B);
      auto L = debugString(D.getLeftSubValue(), Depth + 1);
      auto R = debugString(D.getRightSubValue(), Depth + 1);
      S = formatv("(or\n{0}\n{1})", L, R);
      break;
    }
    case Value::Kind::Negation: {
      auto &N = cast<NegationValue>(B);
      S = formatv("(not\n{0})", debugString(N.getSubVal(), Depth + 1));
      break;
    }
    case Value::Kind::Implication: {
      auto &IV = cast<ImplicationValue>(B);
      auto L = debugString(IV.getLeftSubValue(), Depth + 1);
      auto R = debugString(IV.getRightSubValue(), Depth + 1);
      S = formatv("(=>\n{0}\n{1})", L, R);
      break;
    }
    case Value::Kind::Biconditional: {
      auto &BV = cast<BiconditionalValue>(B);
      auto L = debugString(BV.getLeftSubValue(), Depth + 1);
      auto R = debugString(BV.getRightSubValue(), Depth + 1);
      S = formatv("(=\n{0}\n{1})", L, R);
      break;
    }
    default:
      llvm_unreachable("Unhandled value kind");
    }
    auto Indent = Depth * 4;
    return formatv("{0}", fmt_pad(S, Indent, 0));
  }
 
  std::string debugString(const llvm::DenseSet<BoolValue *> &Constraints) {
    std::vector<std::string> ConstraintsStrings;
    ConstraintsStrings.reserve(Constraints.size());
    for (BoolValue *Constraint : Constraints) {
      ConstraintsStrings.push_back(debugString(*Constraint));
    }
    llvm::sort(ConstraintsStrings);
 
    std::string Result;
    for (const std::string &S : ConstraintsStrings) {
      Result += S;
      Result += '\n';
    }
    return Result;
  }
 
  /// Returns a string representation of a set of boolean `Constraints` and the
  /// `Result` of satisfiability checking on the `Constraints`.
  std::string debugString(ArrayRef<BoolValue *> &Constraints,
                          const Solver::Result &Result) {
    auto Template = R"(
Constraints
------------
{0:$[
 
]}
------------
{1}.
{2}
)";
 
    std::vector<std::string> ConstraintsStrings;
    ConstraintsStrings.reserve(Constraints.size());
    for (auto &Constraint : Constraints) {
      ConstraintsStrings.push_back(debugString(*Constraint));
    }
 
    auto StatusString = clang::dataflow::debugString(Result.getStatus());
    auto Solution = Result.getSolution();
    auto SolutionString = Solution ? "\n" + debugString(Solution.value()) : "";
 
    return formatv(
        Template,
        llvm::make_range(ConstraintsStrings.begin(), ConstraintsStrings.end()),
        StatusString, SolutionString);
  }
 
private:
  /// Returns a string representation of a truth assignment to atom booleans.
  std::string debugString(
      const llvm::DenseMap<AtomicBoolValue *, Solver::Result::Assignment>
          &AtomAssignments) {
    size_t MaxNameLength = 0;
    for (auto &AtomName : AtomNames) {
      MaxNameLength = std::max(MaxNameLength, AtomName.second.size());
    }
 
    std::vector<std::string> Lines;
    for (auto &AtomAssignment : AtomAssignments) {
      auto Line = formatv("{0} = {1}",
                          fmt_align(getAtomName(AtomAssignment.first),
                                    AlignStyle::Left, MaxNameLength),
                          clang::dataflow::debugString(AtomAssignment.second));
      Lines.push_back(Line);
    }
    llvm::sort(Lines);
 
    return formatv("{0:$[\n]}", llvm::make_range(Lines.begin(), Lines.end()));
  }
 
  /// Returns the name assigned to `Atom`, either user-specified or created by
  /// default rules (B0, B1, ...).
  std::string getAtomName(const AtomicBoolValue *Atom) {
    auto Entry = AtomNames.try_emplace(Atom, formatv("B{0}", Counter));
    if (Entry.second) {
      Counter++;
    }
    return Entry.first->second;
  }
 
  // Keep track of number of atoms without a user-specified name, used to assign
  // non-repeating default names to such atoms.
  size_t Counter;
 
  // Keep track of names assigned to atoms.
  llvm::DenseMap<const AtomicBoolValue *, std::string> AtomNames;
};
 
} // namespace
 
std::string
debugString(const BoolValue &B,
            llvm::DenseMap<const AtomicBoolValue *, std::string> AtomNames) {
  return DebugStringGenerator(std::move(AtomNames)).debugString(B);
}
 
std::string
debugString(const llvm::DenseSet<BoolValue *> &Constraints,
            llvm::DenseMap<const AtomicBoolValue *, std::string> AtomNames) {
  return DebugStringGenerator(std::move(AtomNames)).debugString(Constraints);
}
 
std::string
debugString(ArrayRef<BoolValue *> Constraints, const Solver::Result &Result,
            llvm::DenseMap<const AtomicBoolValue *, std::string> AtomNames) {
  return DebugStringGenerator(std::move(AtomNames))
      .debugString(Constraints, Result);
}
 
} // namespace dataflow
} // namespace clang