//===- PartialDiagnostic.h - Diagnostic "closures" --------------*- 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

//

//===----------------------------------------------------------------------===//

//

/// \file

/// Implements a partial diagnostic that can be emitted anwyhere

/// in a DiagnosticBuilder stream.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_BASIC_PARTIALDIAGNOSTIC_H

#define LLVM_CLANG_BASIC_PARTIALDIAGNOSTIC_H

#include "clang/Basic/Diagnostic.h"

#include "clang/Basic/LLVM.h"

#include "clang/Basic/SourceLocation.h"

#include "llvm/ADT/SmallVector.h"

#include "llvm/ADT/StringRef.h"

#include <cassert>

#include <cstdint>

#include <string>

#include <type_traits>

#include <utility>

namespace clang {

class DeclContext;

class IdentifierInfo;

class PartialDiagnostic {

public:

  enum {

      // The MaxArguments and MaxFixItHints member enum values from

      // DiagnosticsEngine are private but DiagnosticsEngine declares

      // PartialDiagnostic a friend.  These enum values are redeclared

      // here so that the nested Storage class below can access them.

      MaxArguments = DiagnosticsEngine::MaxArguments

  };

  struct Storage {

    enum {

        /// The maximum number of arguments we can hold. We

        /// currently only support up to 10 arguments (%0-%9).

        ///

        /// A single diagnostic with more than that almost certainly has to

        /// be simplified anyway.

        MaxArguments = PartialDiagnostic::MaxArguments

    };

    /// The number of entries in Arguments.

    unsigned char NumDiagArgs = 0;

    /// Specifies for each argument whether it is in DiagArgumentsStr

    /// or in DiagArguments.

    unsigned char DiagArgumentsKind[MaxArguments];

    /// The values for the various substitution positions.

    ///

    /// This is used when the argument is not an std::string. The specific value

    /// is mangled into an intptr_t and the interpretation depends on exactly

    /// what sort of argument kind it is.

    intptr_t DiagArgumentsVal[MaxArguments];

    /// The values for the various substitution positions that have

    /// string arguments.

    std::string DiagArgumentsStr[MaxArguments];

    /// The list of ranges added to this diagnostic.

    SmallVector<CharSourceRange, 8> DiagRanges;

    /// If valid, provides a hint with some code to insert, remove, or

    /// modify at a particular position.

    SmallVector<FixItHint, 6>  FixItHints;

    Storage() = default;

  };

  /// An allocator for Storage objects, which uses a small cache to

  /// objects, used to reduce malloc()/free() traffic for partial diagnostics.

  class StorageAllocator {

    static const unsigned NumCached = 16;

    Storage Cached[NumCached];

    Storage *FreeList[NumCached];

    unsigned NumFreeListEntries;

  public:

    StorageAllocator();

    ~StorageAllocator();

    /// Allocate new storage.

    Storage *Allocate() {

      if (NumFreeListEntries == 0)

        return new Storage;

      Storage *Result = FreeList[--NumFreeListEntries];

      Result->NumDiagArgs = 0;

      Result->DiagRanges.clear();

      Result->FixItHints.clear();

      return Result;

    }

    /// Free the given storage object.

    void Deallocate(Storage *S) {

      if (S >= Cached && 
S <= Cached + NumCached1.15M
) {

        FreeList[NumFreeListEntries++] = S;

        return;

      }

      delete S;

    }

  };

private:

  // NOTE: Sema assumes that PartialDiagnostic is location-invariant

  // in the sense that its bits can be safely memcpy'ed and destructed

  // in the new location.

  /// The diagnostic ID.

  mutable unsigned DiagID = 0;

  /// Storage for args and ranges.

  mutable Storage *DiagStorage = nullptr;

  /// Allocator used to allocate storage for this diagnostic.

  StorageAllocator *Allocator = nullptr;

  /// Retrieve storage for this particular diagnostic.

  Storage *getStorage() const {

    if (DiagStorage)

      return DiagStorage;

    if (Allocator)

      DiagStorage = Allocator->Allocate();

    else {

      assert(Allocator != reinterpret_cast<StorageAllocator *>(~uintptr_t(0)));

      DiagStorage = new Storage;

    }

    return DiagStorage;

  }

  void freeStorage() {

    if (!DiagStorage)

      return;

    // The hot path for PartialDiagnostic is when we just used it to wrap an ID

    // (typically so we have the flexibility of passing a more complex

    // diagnostic into the callee, but that does not commonly occur).

    //

    // Split this out into a slow function for silly compilers (*cough*) which

    // can't do decent partial inlining.

    freeStorageSlow();

  }

  void freeStorageSlow() {

    if (Allocator)

      Allocator->Deallocate(DiagStorage);

    else if (Allocator != reinterpret_cast<StorageAllocator *>(~uintptr_t(0)))

      delete DiagStorage;

    DiagStorage = nullptr;

  }

  void AddSourceRange(const CharSourceRange &R) const {

    if (!DiagStorage)

      DiagStorage = getStorage();

    DiagStorage->DiagRanges.push_back(R);

  }

  void AddFixItHint(const FixItHint &Hint) const {

    if (Hint.isNull())

      return;

    if (!DiagStorage)

      DiagStorage = getStorage();

    DiagStorage->FixItHints.push_back(Hint);

  }

public:

  struct NullDiagnostic {};

  /// Create a null partial diagnostic, which cannot carry a payload,

  /// and only exists to be swapped with a real partial diagnostic.

  PartialDiagnostic(NullDiagnostic) {}

  PartialDiagnostic(unsigned DiagID, StorageAllocator &Allocator)

      : DiagID(DiagID), Allocator(&Allocator) {}

  PartialDiagnostic(const PartialDiagnostic &Other)

      : DiagID(Other.DiagID), Allocator(Other.Allocator) {

    if (Other.DiagStorage) {

      DiagStorage = getStorage();

      *DiagStorage = *Other.DiagStorage;

    }

  }

  PartialDiagnostic(PartialDiagnostic &&Other)

      : DiagID(Other.DiagID), DiagStorage(Other.DiagStorage),

        Allocator(Other.Allocator) {

    Other.DiagStorage = nullptr;

  }

  PartialDiagnostic(const PartialDiagnostic &Other, Storage *DiagStorage)

      : DiagID(Other.DiagID), DiagStorage(DiagStorage),

        Allocator(reinterpret_cast<StorageAllocator *>(~uintptr_t(0))) {

    if (Other.DiagStorage)

      *this->DiagStorage = *Other.DiagStorage;

  }

  PartialDiagnostic(const Diagnostic &Other, StorageAllocator &Allocator)

      : DiagID(Other.getID()), Allocator(&Allocator) {

    // Copy arguments.

    for (unsigned I = 0, N = Other.getNumArgs(); I != N; 
++I164k
) {

      if (Other.getArgKind(I) == DiagnosticsEngine::ak_std_string)

        AddString(Other.getArgStdStr(I));

      else

        AddTaggedVal(Other.getRawArg(I), Other.getArgKind(I));

    }

    // Copy source ranges.

    for (unsigned I = 0, N = Other.getNumRanges(); I != N; 
++I129k
)

      AddSourceRange(Other.getRange(I));

    // Copy fix-its.

    for (unsigned I = 0, N = Other.getNumFixItHints(); I != N; 
++I75
)

      AddFixItHint(Other.getFixItHint(I));

  }

  PartialDiagnostic &operator=(const PartialDiagnostic &Other) {

    DiagID = Other.DiagID;

    if (Other.DiagStorage) {

      if (!DiagStorage)

        DiagStorage = getStorage();

      *DiagStorage = *Other.DiagStorage;

    } else {

      freeStorage();

    }

    return *this;

  }

  PartialDiagnostic &operator=(PartialDiagnostic &&Other) {

    freeStorage();

    DiagID = Other.DiagID;

    DiagStorage = Other.DiagStorage;

    Allocator = Other.Allocator;

    Other.DiagStorage = nullptr;

    return *this;

  }

  ~PartialDiagnostic() {

    freeStorage();

  }

  void swap(PartialDiagnostic &PD) {

    std::swap(DiagID, PD.DiagID);

    std::swap(DiagStorage, PD.DiagStorage);

    std::swap(Allocator, PD.Allocator);

  }

  unsigned getDiagID() const { return DiagID; }

  void AddTaggedVal(intptr_t V, DiagnosticsEngine::ArgumentKind Kind) const {

    if (!DiagStorage)

      DiagStorage = getStorage();

    assert(DiagStorage->NumDiagArgs < Storage::MaxArguments &&

           "Too many arguments to diagnostic!");

    DiagStorage->DiagArgumentsKind[DiagStorage->NumDiagArgs] = Kind;

    DiagStorage->DiagArgumentsVal[DiagStorage->NumDiagArgs++] = V;

  }

  void AddString(StringRef V) const {

    if (!DiagStorage)

      DiagStorage = getStorage();

    assert(DiagStorage->NumDiagArgs < Storage::MaxArguments &&

           "Too many arguments to diagnostic!");

    DiagStorage->DiagArgumentsKind[DiagStorage->NumDiagArgs]

      = DiagnosticsEngine::ak_std_string;

    DiagStorage->DiagArgumentsStr[DiagStorage->NumDiagArgs++] = std::string(V);

  }

  void Emit(const DiagnosticBuilder &DB) const {

    if (!DiagStorage)

      return;

    // Add all arguments.

    
for (unsigned i = 0, e = DiagStorage->NumDiagArgs; 111k
i != e; 
++i265k
) {

      if ((DiagnosticsEngine::ArgumentKind)DiagStorage->DiagArgumentsKind[i]

            == DiagnosticsEngine::ak_std_string)

        DB.AddString(DiagStorage->DiagArgumentsStr[i]);

      else

        DB.AddTaggedVal(DiagStorage->DiagArgumentsVal[i],

            (DiagnosticsEngine::ArgumentKind)DiagStorage->DiagArgumentsKind[i]);

    }

    // Add all ranges.

    for (const CharSourceRange &Range : DiagStorage->DiagRanges)

      DB.AddSourceRange(Range);

    // Add all fix-its.

    for (const FixItHint &Fix : DiagStorage->FixItHints)

      DB.AddFixItHint(Fix);

  }

  void EmitToString(DiagnosticsEngine &Diags,

                    SmallVectorImpl<char> &Buf) const {

    // FIXME: It should be possible to render a diagnostic to a string without

    //        messing with the state of the diagnostics engine.

    DiagnosticBuilder DB(Diags.Report(getDiagID()));

    Emit(DB);

    DB.FlushCounts();

    Diagnostic(&Diags).FormatDiagnostic(Buf);

    DB.Clear();

    Diags.Clear();

  }

  /// Clear out this partial diagnostic, giving it a new diagnostic ID

  /// and removing all of its arguments, ranges, and fix-it hints.

  void Reset(unsigned DiagID = 0) {

    this->DiagID = DiagID;

    freeStorage();

  }

  bool hasStorage() const { return DiagStorage != nullptr; }

  /// Retrieve the string argument at the given index.

  StringRef getStringArg(unsigned I) {

    assert(DiagStorage && "No diagnostic storage?");

    assert(I < DiagStorage->NumDiagArgs && "Not enough diagnostic args");

    assert(DiagStorage->DiagArgumentsKind[I]

             == DiagnosticsEngine::ak_std_string && "Not a string arg");

    return DiagStorage->DiagArgumentsStr[I];

  }

  friend const PartialDiagnostic &operator<<(const PartialDiagnostic &PD,

                                             unsigned I) {

    PD.AddTaggedVal(I, DiagnosticsEngine::ak_uint);

    return PD;

  }

  friend const PartialDiagnostic &operator<<(const PartialDiagnostic &PD,

                                             int I) {

    PD.AddTaggedVal(I, DiagnosticsEngine::ak_sint);

    return PD;

  }

  friend inline const PartialDiagnostic &operator<<(const PartialDiagnostic &PD,

                                                    const char *S) {

    PD.AddTaggedVal(reinterpret_cast<intptr_t>(S),

                    DiagnosticsEngine::ak_c_string);

    return PD;

  }

  friend inline const PartialDiagnostic &operator<<(const PartialDiagnostic &PD,

                                                    StringRef S) {

    PD.AddString(S);

    return PD;

  }

  friend inline const PartialDiagnostic &operator<<(const PartialDiagnostic &PD,

                                                    const IdentifierInfo *II) {

    PD.AddTaggedVal(reinterpret_cast<intptr_t>(II),

                    DiagnosticsEngine::ak_identifierinfo);

    return PD;

  }

  // Adds a DeclContext to the diagnostic. The enable_if template magic is here

  // so that we only match those arguments that are (statically) DeclContexts;

  // other arguments that derive from DeclContext (e.g., RecordDecls) will not

  // match.

  template <typename T>

  friend inline std::enable_if_t<std::is_same<T, DeclContext>::value,

                                 const PartialDiagnostic &>

  operator<<(const PartialDiagnostic &PD, T *DC) {

    PD.AddTaggedVal(reinterpret_cast<intptr_t>(DC),

                    DiagnosticsEngine::ak_declcontext);

    return PD;

  }

  friend inline const PartialDiagnostic &operator<<(const PartialDiagnostic &PD,

                                                    SourceRange R) {

    PD.AddSourceRange(CharSourceRange::getTokenRange(R));

    return PD;

  }

  friend inline const PartialDiagnostic &operator<<(const PartialDiagnostic &PD,

                                                    const CharSourceRange &R) {

    PD.AddSourceRange(R);

    return PD;

  }

  friend const PartialDiagnostic &operator<<(const PartialDiagnostic &PD,

                                             const FixItHint &Hint) {

    PD.AddFixItHint(Hint);

    return PD;

  }

};

inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,

                                           const PartialDiagnostic &PD) {

  PD.Emit(DB);

  return DB;

}

/// A partial diagnostic along with the source location where this

/// diagnostic occurs.

using PartialDiagnosticAt = std::pair<SourceLocation, PartialDiagnostic>;

} // namespace clang

#endif // LLVM_CLANG_BASIC_PARTIALDIAGNOSTIC_H