//===- ASTVector.h - Vector that uses ASTContext for allocation ---*- 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 provides ASTVector, a vector ADT whose contents are
// allocated using the allocator associated with an ASTContext..
//
//===----------------------------------------------------------------------===//
// FIXME: Most of this is copy-and-paste from BumpVector.h and SmallVector.h.
// We can refactor this core logic into something common.
#ifndef LLVM_CLANG_AST_ASTVECTOR_H
#define LLVM_CLANG_AST_ASTVECTOR_H
#include "clang/AST/ASTContextAllocate.h"
#include "llvm/ADT/PointerIntPair.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstring>
#include <iterator>
#include <memory>
#include <type_traits>
#include <utility>
namespace clang {
class ASTContext;
template<typename T>
class ASTVector {
private:
T *Begin = nullptr;
T *End = nullptr;
llvm::PointerIntPair<T *, 1, bool> Capacity;
void setEnd(T *P) { this->End = P; }
protected:
// Make a tag bit available to users of this class.
// FIXME: This is a horrible hack.
bool getTag() const { return Capacity.getInt(); }
void setTag(bool B) { Capacity.setInt(B); }
public:
// Default ctor - Initialize to empty.
ASTVector() : Capacity(nullptr, false) {}
ASTVector(ASTVector &&O) : Begin(O.Begin), End(O.End), Capacity(O.Capacity) {
O.Begin = O.End = nullptr;
O.Capacity.setPointer(nullptr);
O.Capacity.setInt(false);
}
ASTVector(const ASTContext &C, unsigned N) : Capacity(nullptr, false) {
reserve(C, N);
}
ASTVector &operator=(ASTVector &&RHS) {
ASTVector O(std::move(RHS));
using std::swap;
swap(Begin, O.Begin);
swap(End, O.End);
swap(Capacity, O.Capacity);
return *this;
}
~ASTVector() {
if (std::is_class<T>::value) {
// Destroy the constructed elements in the vector.
destroy_range(Begin, End);
}
}
using size_type = size_t;
using difference_type = ptrdiff_t;
using value_type = T;
using iterator = T *;
using const_iterator = const T *;
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
using reverse_iterator = std::reverse_iterator<iterator>;
using reference = T &;
using const_reference = const T &;
using pointer = T *;
using const_pointer = const T *;
// forward iterator creation methods.
iterator begin() { return Begin; }
const_iterator begin() const { return Begin; }
iterator end() { return End; }
const_iterator end() const { return End; }
// reverse iterator creation methods.
reverse_iterator rbegin() { return reverse_iterator(end()); }
const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
reverse_iterator rend() { return reverse_iterator(begin()); }
const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
bool empty() const { return Begin == End; }
size_type size() const { return End-Begin; }
reference operator[](unsigned idx) {
assert(Begin + idx < End);
return Begin[idx];
}
const_reference operator[](unsigned idx) const {
assert(Begin + idx < End);
return Begin[idx];
}
reference front() {
return begin()[0];
}
const_reference front() const {
return begin()[0];
}
reference back() {
return end()[-1];
}
const_reference back() const {
return end()[-1];
}
void pop_back() {
--End;
End->~T();
}
T pop_back_val() {
T Result = back();
pop_back();
return Result;
}
void clear() {
if (std::is_class<T>::value) {
destroy_range(Begin, End);
}
End = Begin;
}
/// data - Return a pointer to the vector's buffer, even if empty().
pointer data() {
return pointer(Begin);
}
/// data - Return a pointer to the vector's buffer, even if empty().
const_pointer data() const {
return const_pointer(Begin);
}
void push_back(const_reference Elt, const ASTContext &C) {
if (End < this->capacity_ptr()) {
Retry:
new (End) T(Elt);
++End;
return;
}
grow(C);
goto Retry;
}
void reserve(const ASTContext &C, unsigned N) {
if (unsigned(this->capacity_ptr()-Begin) < N)
grow(C, N);
}
/// capacity - Return the total number of elements in the currently allocated
/// buffer.
size_t capacity() const { return this->capacity_ptr() - Begin; }
/// append - Add the specified range to the end of the SmallVector.
template<typename in_iter>
void append(const ASTContext &C, in_iter in_start, in_iter in_end) {
size_type NumInputs = std::distance(in_start, in_end);
if (NumInputs == 0)
return;
// Grow allocated space if needed.
if (NumInputs > size_type(this->capacity_ptr()-this->end()))
this->grow(C, this->size()+NumInputs);
// Copy the new elements over.
// TODO: NEED To compile time dispatch on whether in_iter is a random access
// iterator to use the fast uninitialized_copy.
std::uninitialized_copy(in_start, in_end, this->end());
this->setEnd(this->end() + NumInputs);
}
/// append - Add the specified range to the end of the SmallVector.
void append(const ASTContext &C, size_type NumInputs, const T &Elt) {
// Grow allocated space if needed.
if (NumInputs > size_type(this->capacity_ptr()-this->end()))
this->grow(C, this->size()+NumInputs);
// Copy the new elements over.
std::uninitialized_fill_n(this->end(), NumInputs, Elt);
this->setEnd(this->end() + NumInputs);
}
/// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory
/// starting with "Dest", constructing elements into it as needed.
template<typename It1, typename It2>
static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
std::uninitialized_copy(I, E, Dest);
}
iterator insert(const ASTContext &C, iterator I, const T &Elt) {
if (I == this->end()) { // Important special case for empty vector.
push_back(Elt, C);
return this->end()-1;
}
if (this->End < this->capacity_ptr()) {
Retry:
new (this->end()) T(this->back());
this->setEnd(this->end()+1);
// Push everything else over.
std::copy_backward(I, this->end()-1, this->end());
*I = Elt;
return I;
}
size_t EltNo = I-this->begin();
this->grow(C);
I = this->begin()+EltNo;
goto Retry;
}
iterator insert(const ASTContext &C, iterator I, size_type NumToInsert,
const T &Elt) {
// Convert iterator to elt# to avoid invalidating iterator when we reserve()
size_t InsertElt = I - this->begin();
if (I == this->end()) { // Important special case for empty vector.
append(C, NumToInsert, Elt);
return this->begin() + InsertElt;
}
// Ensure there is enough space.
reserve(C, static_cast<unsigned>(this->size() + NumToInsert));
// Uninvalidate the iterator.
I = this->begin()+InsertElt;
// If there are more elements between the insertion point and the end of the
// range than there are being inserted, we can use a simple approach to
// insertion. Since we already reserved space, we know that this won't
// reallocate the vector.
if (size_t(this->end()-I) >= NumToInsert) {
T *OldEnd = this->end();
append(C, this->end()-NumToInsert, this->end());
// Copy the existing elements that get replaced.
std::copy_backward(I, OldEnd-NumToInsert, OldEnd);
std::fill_n(I, NumToInsert, Elt);
return I;
}
// Otherwise, we're inserting more elements than exist already, and we're
// not inserting at the end.
// Copy over the elements that we're about to overwrite.
T *OldEnd = this->end();
this->setEnd(this->end() + NumToInsert);
size_t NumOverwritten = OldEnd-I;
this->uninitialized_copy(I, OldEnd, this->end()-NumOverwritten);
// Replace the overwritten part.
std::fill_n(I, NumOverwritten, Elt);
// Insert the non-overwritten middle part.
std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt);
return I;
}
template<typename ItTy>
iterator insert(const ASTContext &C, iterator I, ItTy From, ItTy To) {
// Convert iterator to elt# to avoid invalidating iterator when we reserve()
size_t InsertElt = I - this->begin();
if (I == this->end()) { // Important special case for empty vector.
append(C, From, To);
return this->begin() + InsertElt;
}
size_t NumToInsert = std::distance(From, To);
// Ensure there is enough space.
reserve(C, static_cast<unsigned>(this->size() + NumToInsert));
// Uninvalidate the iterator.
I = this->begin()+InsertElt;
// If there are more elements between the insertion point and the end of the
// range than there are being inserted, we can use a simple approach to
// insertion. Since we already reserved space, we know that this won't
// reallocate the vector.
if (size_t(this->end()-I) >= NumToInsert) {
T *OldEnd = this->end();
append(C, this->end()-NumToInsert, this->end());
// Copy the existing elements that get replaced.
std::copy_backward(I, OldEnd-NumToInsert, OldEnd);
std::copy(From, To, I);
return I;
}
// Otherwise, we're inserting more elements than exist already, and we're
// not inserting at the end.
// Copy over the elements that we're about to overwrite.
T *OldEnd = this->end();
this->setEnd(this->end() + NumToInsert);
size_t NumOverwritten = OldEnd-I;
this->uninitialized_copy(I, OldEnd, this->end()-NumOverwritten);
// Replace the overwritten part.
for (; NumOverwritten > 0; --NumOverwritten) {
*I = *From;
++I; ++From;
}
// Insert the non-overwritten middle part.
this->uninitialized_copy(From, To, OldEnd);
return I;
}
void resize(const ASTContext &C, unsigned N, const T &NV) {
if (N < this->size()) {
this->destroy_range(this->begin()+N, this->end());
this->setEnd(this->begin()+N);
} else if (N > this->size()) {
if (this->capacity() < N)
this->grow(C, N);
construct_range(this->end(), this->begin()+N, NV);
this->setEnd(this->begin()+N);
}
}
private:
/// grow - double the size of the allocated memory, guaranteeing space for at
/// least one more element or MinSize if specified.
void grow(const ASTContext &C, size_type MinSize = 1);
void construct_range(T *S, T *E, const T &Elt) {
for (; S != E; ++S)
new (S) T(Elt);
}
void destroy_range(T *S, T *E) {
while (S != E) {
--E;
E->~T();
}
}
protected:
const_iterator capacity_ptr() const {
return (iterator) Capacity.getPointer();
}
iterator capacity_ptr() { return (iterator)Capacity.getPointer(); }
};
// Define this out-of-line to dissuade the C++ compiler from inlining it.
template <typename T>
void ASTVector<T>::grow(const ASTContext &C, size_t MinSize) {
size_t CurCapacity = this->capacity();
size_t CurSize = size();
size_t NewCapacity = 2*CurCapacity;
if (NewCapacity < MinSize)
NewCapacity = MinSize;
// Allocate the memory from the ASTContext.
T *NewElts = new (C, alignof(T)) T[NewCapacity];
// Copy the elements over.
if (Begin != End) {
if (std::is_class<T>::value) {
std::uninitialized_copy(Begin, End, NewElts);
// Destroy the original elements.
destroy_range(Begin, End);
} else {
// Use memcpy for PODs (std::uninitialized_copy optimizes to memmove).
memcpy(NewElts, Begin, CurSize * sizeof(T));
}
}
// ASTContext never frees any memory.
Begin = NewElts;
End = NewElts+CurSize;
Capacity.setPointer(Begin+NewCapacity);
}
} // namespace clang
#endif // LLVM_CLANG_AST_ASTVECTOR_H