1//===- ASTVector.h - Vector that uses ASTContext for allocation ---*- C++ -*-=//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file provides ASTVector, a vector ADT whose contents are
11// allocated using the allocator associated with an ASTContext..
12//
13//===----------------------------------------------------------------------===//
14
15// FIXME: Most of this is copy-and-paste from BumpVector.h and SmallVector.h.
16// We can refactor this core logic into something common.
17
18#ifndef LLVM_CLANG_AST_ASTVECTOR_H
19#define LLVM_CLANG_AST_ASTVECTOR_H
20
21#include "llvm/ADT/PointerIntPair.h"
22#include <algorithm>
23#include <cassert>
24#include <cstddef>
25#include <cstring>
26#include <iterator>
27#include <memory>
28#include <type_traits>
29#include <utility>
30
31namespace clang {
32
33class ASTContext;
34
35template<typename T>
36class ASTVector {
37private:
38 T *Begin = nullptr;
39 T *End = nullptr;
40 llvm::PointerIntPair<T *, 1, bool> Capacity;
41
42 void setEnd(T *P) { this->End = P; }
43
44protected:
45 // Make a tag bit available to users of this class.
46 // FIXME: This is a horrible hack.
47 bool getTag() const { return Capacity.getInt(); }
48 void setTag(bool B) { Capacity.setInt(B); }
49
50public:
51 // Default ctor - Initialize to empty.
52 ASTVector() : Capacity(nullptr, false) {}
53
54 ASTVector(ASTVector &&O) : Begin(O.Begin), End(O.End), Capacity(O.Capacity) {
55 O.Begin = O.End = nullptr;
56 O.Capacity.setPointer(nullptr);
57 O.Capacity.setInt(false);
58 }
59
60 ASTVector(const ASTContext &C, unsigned N) : Capacity(nullptr, false) {
61 reserve(C, N);
62 }
63
64 ASTVector &operator=(ASTVector &&RHS) {
65 ASTVector O(std::move(RHS));
66
67 using std::swap;
68
69 swap(Begin, O.Begin);
70 swap(End, O.End);
71 swap(Capacity, O.Capacity);
72 return *this;
73 }
74
75 ~ASTVector() {
76 if (std::is_class<T>::value) {
77 // Destroy the constructed elements in the vector.
78 destroy_range(Begin, End);
79 }
80 }
81
82 using size_type = size_t;
83 using difference_type = ptrdiff_t;
84 using value_type = T;
85 using iterator = T *;
86 using const_iterator = const T *;
87
88 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
89 using reverse_iterator = std::reverse_iterator<iterator>;
90
91 using reference = T &;
92 using const_reference = const T &;
93 using pointer = T *;
94 using const_pointer = const T *;
95
96 // forward iterator creation methods.
97 iterator begin() { return Begin; }
98 const_iterator begin() const { return Begin; }
99 iterator end() { return End; }
100 const_iterator end() const { return End; }
101
102 // reverse iterator creation methods.
103 reverse_iterator rbegin() { return reverse_iterator(end()); }
104 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
105 reverse_iterator rend() { return reverse_iterator(begin()); }
106 const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
107
108 bool empty() const { return Begin == End; }
109 size_type size() const { return End-Begin; }
110
111 reference operator[](unsigned idx) {
112 assert(Begin + idx < End);
113 return Begin[idx];
114 }
115 const_reference operator[](unsigned idx) const {
116 assert(Begin + idx < End);
117 return Begin[idx];
118 }
119
120 reference front() {
121 return begin()[0];
122 }
123 const_reference front() const {
124 return begin()[0];
125 }
126
127 reference back() {
128 return end()[-1];
129 }
130 const_reference back() const {
131 return end()[-1];
132 }
133
134 void pop_back() {
135 --End;
136 End->~T();
137 }
138
139 T pop_back_val() {
140 T Result = back();
141 pop_back();
142 return Result;
143 }
144
145 void clear() {
146 if (std::is_class<T>::value) {
147 destroy_range(Begin, End);
148 }
149 End = Begin;
150 }
151
152 /// data - Return a pointer to the vector's buffer, even if empty().
153 pointer data() {
154 return pointer(Begin);
155 }
156
157 /// data - Return a pointer to the vector's buffer, even if empty().
158 const_pointer data() const {
159 return const_pointer(Begin);
160 }
161
162 void push_back(const_reference Elt, const ASTContext &C) {
163 if (End < this->capacity_ptr()) {
164 Retry:
165 new (End) T(Elt);
166 ++End;
167 return;
168 }
169 grow(C);
170 goto Retry;
171 }
172
173 void reserve(const ASTContext &C, unsigned N) {
174 if (unsigned(this->capacity_ptr()-Begin) < N)
175 grow(C, N);
176 }
177
178 /// capacity - Return the total number of elements in the currently allocated
179 /// buffer.
180 size_t capacity() const { return this->capacity_ptr() - Begin; }
181
182 /// append - Add the specified range to the end of the SmallVector.
183 template<typename in_iter>
184 void append(const ASTContext &C, in_iter in_start, in_iter in_end) {
185 size_type NumInputs = std::distance(in_start, in_end);
186
187 if (NumInputs == 0)
188 return;
189
190 // Grow allocated space if needed.
191 if (NumInputs > size_type(this->capacity_ptr()-this->end()))
192 this->grow(C, this->size()+NumInputs);
193
194 // Copy the new elements over.
195 // TODO: NEED To compile time dispatch on whether in_iter is a random access
196 // iterator to use the fast uninitialized_copy.
197 std::uninitialized_copy(in_start, in_end, this->end());
198 this->setEnd(this->end() + NumInputs);
199 }
200
201 /// append - Add the specified range to the end of the SmallVector.
202 void append(const ASTContext &C, size_type NumInputs, const T &Elt) {
203 // Grow allocated space if needed.
204 if (NumInputs > size_type(this->capacity_ptr()-this->end()))
205 this->grow(C, this->size()+NumInputs);
206
207 // Copy the new elements over.
208 std::uninitialized_fill_n(this->end(), NumInputs, Elt);
209 this->setEnd(this->end() + NumInputs);
210 }
211
212 /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory
213 /// starting with "Dest", constructing elements into it as needed.
214 template<typename It1, typename It2>
215 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
216 std::uninitialized_copy(I, E, Dest);
217 }
218
219 iterator insert(const ASTContext &C, iterator I, const T &Elt) {
220 if (I == this->end()) { // Important special case for empty vector.
221 push_back(Elt, C);
222 return this->end()-1;
223 }
224
225 if (this->End < this->capacity_ptr()) {
226 Retry:
227 new (this->end()) T(this->back());
228 this->setEnd(this->end()+1);
229 // Push everything else over.
230 std::copy_backward(I, this->end()-1, this->end());
231 *I = Elt;
232 return I;
233 }
234 size_t EltNo = I-this->begin();
235 this->grow(C);
236 I = this->begin()+EltNo;
237 goto Retry;
238 }
239
240 iterator insert(const ASTContext &C, iterator I, size_type NumToInsert,
241 const T &Elt) {
242 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
243 size_t InsertElt = I - this->begin();
244
245 if (I == this->end()) { // Important special case for empty vector.
246 append(C, NumToInsert, Elt);
247 return this->begin() + InsertElt;
248 }
249
250 // Ensure there is enough space.
251 reserve(C, static_cast<unsigned>(this->size() + NumToInsert));
252
253 // Uninvalidate the iterator.
254 I = this->begin()+InsertElt;
255
256 // If there are more elements between the insertion point and the end of the
257 // range than there are being inserted, we can use a simple approach to
258 // insertion. Since we already reserved space, we know that this won't
259 // reallocate the vector.
260 if (size_t(this->end()-I) >= NumToInsert) {
261 T *OldEnd = this->end();
262 append(C, this->end()-NumToInsert, this->end());
263
264 // Copy the existing elements that get replaced.
265 std::copy_backward(I, OldEnd-NumToInsert, OldEnd);
266
267 std::fill_n(I, NumToInsert, Elt);
268 return I;
269 }
270
271 // Otherwise, we're inserting more elements than exist already, and we're
272 // not inserting at the end.
273
274 // Copy over the elements that we're about to overwrite.
275 T *OldEnd = this->end();
276 this->setEnd(this->end() + NumToInsert);
277 size_t NumOverwritten = OldEnd-I;
278 this->uninitialized_copy(I, OldEnd, this->end()-NumOverwritten);
279
280 // Replace the overwritten part.
281 std::fill_n(I, NumOverwritten, Elt);
282
283 // Insert the non-overwritten middle part.
284 std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt);
285 return I;
286 }
287
288 template<typename ItTy>
289 iterator insert(const ASTContext &C, iterator I, ItTy From, ItTy To) {
290 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
291 size_t InsertElt = I - this->begin();
292
293 if (I == this->end()) { // Important special case for empty vector.
294 append(C, From, To);
295 return this->begin() + InsertElt;
296 }
297
298 size_t NumToInsert = std::distance(From, To);
299
300 // Ensure there is enough space.
301 reserve(C, static_cast<unsigned>(this->size() + NumToInsert));
302
303 // Uninvalidate the iterator.
304 I = this->begin()+InsertElt;
305
306 // If there are more elements between the insertion point and the end of the
307 // range than there are being inserted, we can use a simple approach to
308 // insertion. Since we already reserved space, we know that this won't
309 // reallocate the vector.
310 if (size_t(this->end()-I) >= NumToInsert) {
311 T *OldEnd = this->end();
312 append(C, this->end()-NumToInsert, this->end());
313
314 // Copy the existing elements that get replaced.
315 std::copy_backward(I, OldEnd-NumToInsert, OldEnd);
316
317 std::copy(From, To, I);
318 return I;
319 }
320
321 // Otherwise, we're inserting more elements than exist already, and we're
322 // not inserting at the end.
323
324 // Copy over the elements that we're about to overwrite.
325 T *OldEnd = this->end();
326 this->setEnd(this->end() + NumToInsert);
327 size_t NumOverwritten = OldEnd-I;
328 this->uninitialized_copy(I, OldEnd, this->end()-NumOverwritten);
329
330 // Replace the overwritten part.
331 for (; NumOverwritten > 0; --NumOverwritten) {
332 *I = *From;
333 ++I; ++From;
334 }
335
336 // Insert the non-overwritten middle part.
337 this->uninitialized_copy(From, To, OldEnd);
338 return I;
339 }
340
341 void resize(const ASTContext &C, unsigned N, const T &NV) {
342 if (N < this->size()) {
343 this->destroy_range(this->begin()+N, this->end());
344 this->setEnd(this->begin()+N);
345 } else if (N > this->size()) {
346 if (this->capacity() < N)
347 this->grow(C, N);
348 construct_range(this->end(), this->begin()+N, NV);
349 this->setEnd(this->begin()+N);
350 }
351 }
352
353private:
354 /// grow - double the size of the allocated memory, guaranteeing space for at
355 /// least one more element or MinSize if specified.
356 void grow(const ASTContext &C, size_type MinSize = 1);
357
358 void construct_range(T *S, T *E, const T &Elt) {
359 for (; S != E; ++S)
360 new (S) T(Elt);
361 }
362
363 void destroy_range(T *S, T *E) {
364 while (S != E) {
365 --E;
366 E->~T();
367 }
368 }
369
370protected:
371 const_iterator capacity_ptr() const {
372 return (iterator) Capacity.getPointer();
373 }
374
375 iterator capacity_ptr() { return (iterator)Capacity.getPointer(); }
376};
377
378// Define this out-of-line to dissuade the C++ compiler from inlining it.
379template <typename T>
380void ASTVector<T>::grow(const ASTContext &C, size_t MinSize) {
381 size_t CurCapacity = this->capacity();
382 size_t CurSize = size();
383 size_t NewCapacity = 2*CurCapacity;
384 if (NewCapacity < MinSize)
385 NewCapacity = MinSize;
386
387 // Allocate the memory from the ASTContext.
388 T *NewElts = new (C, alignof(T)) T[NewCapacity];
389
390 // Copy the elements over.
391 if (Begin != End) {
392 if (std::is_class<T>::value) {
393 std::uninitialized_copy(Begin, End, NewElts);
394 // Destroy the original elements.
395 destroy_range(Begin, End);
396 } else {
397 // Use memcpy for PODs (std::uninitialized_copy optimizes to memmove).
398 memcpy(NewElts, Begin, CurSize * sizeof(T));
399 }
400 }
401
402 // ASTContext never frees any memory.
403 Begin = NewElts;
404 End = NewElts+CurSize;
405 Capacity.setPointer(Begin+NewCapacity);
406}
407
408} // namespace clang
409
410#endif // LLVM_CLANG_AST_ASTVECTOR_H
411