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1 //===-------------------------- cxa_vector.cpp ---------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //
9 //  This file implements the "Array Construction and Destruction APIs"
10 //  http://mentorembedded.github.io/cxx-abi/abi.html#array-ctor
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "cxxabi.h"
15 
16 #include <exception>        // for std::terminate
17 
18 namespace __cxxabiv1 {
19 
20 #if 0
21 #pragma mark --Helper routines and classes --
22 #endif
23 
24 namespace {
__get_element_count(void * p)25     inline static size_t __get_element_count ( void *p ) {
26         return static_cast <size_t *> (p)[-1];
27         }
28 
__set_element_count(void * p,size_t element_count)29     inline static void __set_element_count ( void *p, size_t element_count ) {
30         static_cast <size_t *> (p)[-1] = element_count;
31         }
32 
33 
34 //  A pair of classes to simplify exception handling and control flow.
35 //  They get passed a block of memory in the constructor, and unless the
36 //  'release' method is called, they deallocate the memory in the destructor.
37 //  Preferred usage is to allocate some memory, attach it to one of these objects,
38 //  and then, when all the operations to set up the memory block have succeeded,
39 //  call 'release'. If any of the setup operations fail, or an exception is
40 //  thrown, then the block is automatically deallocated.
41 //
42 //  The only difference between these two classes is the signature for the
43 //  deallocation function (to match new2/new3 and delete2/delete3.
44     class st_heap_block2 {
45     public:
46         typedef void (*dealloc_f)(void *);
47 
st_heap_block2(dealloc_f dealloc,void * ptr)48         st_heap_block2 ( dealloc_f dealloc, void *ptr )
49             : dealloc_ ( dealloc ), ptr_ ( ptr ), enabled_ ( true ) {}
~st_heap_block2()50         ~st_heap_block2 () { if ( enabled_ ) dealloc_ ( ptr_ ) ; }
release()51         void release () { enabled_ = false; }
52 
53     private:
54         dealloc_f dealloc_;
55         void *ptr_;
56         bool enabled_;
57     };
58 
59     class st_heap_block3 {
60     public:
61         typedef void (*dealloc_f)(void *, size_t);
62 
st_heap_block3(dealloc_f dealloc,void * ptr,size_t size)63         st_heap_block3 ( dealloc_f dealloc, void *ptr, size_t size )
64             : dealloc_ ( dealloc ), ptr_ ( ptr ), size_ ( size ), enabled_ ( true ) {}
~st_heap_block3()65         ~st_heap_block3 () { if ( enabled_ ) dealloc_ ( ptr_, size_ ) ; }
release()66         void release () { enabled_ = false; }
67 
68     private:
69         dealloc_f dealloc_;
70         void *ptr_;
71         size_t size_;
72         bool enabled_;
73     };
74 
75     class st_cxa_cleanup {
76     public:
77         typedef void (*destruct_f)(void *);
78 
st_cxa_cleanup(void * ptr,size_t & idx,size_t element_size,destruct_f destructor)79         st_cxa_cleanup ( void *ptr, size_t &idx, size_t element_size, destruct_f destructor )
80             : ptr_ ( ptr ), idx_ ( idx ), element_size_ ( element_size ),
81                 destructor_ ( destructor ), enabled_ ( true ) {}
~st_cxa_cleanup()82         ~st_cxa_cleanup () {
83             if ( enabled_ )
84                 __cxa_vec_cleanup ( ptr_, idx_, element_size_, destructor_ );
85             }
86 
release()87         void release () { enabled_ = false; }
88 
89     private:
90         void *ptr_;
91         size_t &idx_;
92         size_t element_size_;
93         destruct_f destructor_;
94         bool enabled_;
95     };
96 
97     class st_terminate {
98     public:
st_terminate(bool enabled=true)99         st_terminate ( bool enabled = true ) : enabled_ ( enabled ) {}
~st_terminate()100         ~st_terminate () { if ( enabled_ ) std::terminate (); }
release()101         void release () { enabled_ = false; }
102     private:
103         bool enabled_ ;
104     };
105 }
106 
107 #if 0
108 #pragma mark --Externally visible routines--
109 #endif
110 
111 extern "C" {
112 
113 // Equivalent to
114 //
115 //   __cxa_vec_new2(element_count, element_size, padding_size, constructor,
116 //                  destructor, &::operator new[], &::operator delete[])
__cxa_vec_new(size_t element_count,size_t element_size,size_t padding_size,void (* constructor)(void *),void (* destructor)(void *))117 void* __cxa_vec_new(
118     size_t element_count, size_t element_size, size_t padding_size,
119         void (*constructor)(void*), void (*destructor)(void*) ) {
120 
121     return __cxa_vec_new2 ( element_count, element_size, padding_size,
122         constructor, destructor, &::operator new [], &::operator delete [] );
123 }
124 
125 
126 
127 // Given the number and size of elements for an array and the non-negative
128 // size of prefix padding for a cookie, allocate space (using alloc) for
129 // the array preceded by the specified padding, initialize the cookie if
130 // the padding is non-zero, and call the given constructor on each element.
131 // Return the address of the array proper, after the padding.
132 //
133 // If alloc throws an exception, rethrow the exception. If alloc returns
134 // NULL, return NULL. If the constructor throws an exception, call
135 // destructor for any already constructed elements, and rethrow the
136 // exception. If the destructor throws an exception, call std::terminate.
137 //
138 // The constructor may be NULL, in which case it must not be called. If the
139 // padding_size is zero, the destructor may be NULL; in that case it must
140 // not be called.
141 //
142 // Neither alloc nor dealloc may be NULL.
__cxa_vec_new2(size_t element_count,size_t element_size,size_t padding_size,void (* constructor)(void *),void (* destructor)(void *),void * (* alloc)(size_t),void (* dealloc)(void *))143 void* __cxa_vec_new2(
144     size_t element_count, size_t element_size, size_t padding_size,
145         void  (*constructor)(void*), void  (*destructor)(void*),
146         void* (*alloc)(size_t), void  (*dealloc)(void*) ) {
147 
148     const size_t heap_size = element_count * element_size + padding_size;
149     char * const heap_block = static_cast<char *> ( alloc ( heap_size ));
150     char *vec_base = heap_block;
151 
152     if ( NULL != vec_base ) {
153         st_heap_block2 heap ( dealloc, heap_block );
154 
155     //  put the padding before the array elements
156         if ( 0 != padding_size ) {
157             vec_base += padding_size;
158             __set_element_count ( vec_base, element_count );
159         }
160 
161     //  Construct the elements
162         __cxa_vec_ctor ( vec_base, element_count, element_size, constructor, destructor );
163         heap.release ();    // We're good!
164     }
165 
166     return vec_base;
167 }
168 
169 
170 // Same as __cxa_vec_new2 except that the deallocation function takes both
171 // the object address and its size.
__cxa_vec_new3(size_t element_count,size_t element_size,size_t padding_size,void (* constructor)(void *),void (* destructor)(void *),void * (* alloc)(size_t),void (* dealloc)(void *,size_t))172 void* __cxa_vec_new3(
173     size_t element_count, size_t element_size, size_t padding_size,
174         void  (*constructor)(void*), void  (*destructor)(void*),
175         void* (*alloc)(size_t), void  (*dealloc)(void*, size_t) ) {
176 
177     const size_t heap_size = element_count * element_size + padding_size;
178     char * const heap_block = static_cast<char *> ( alloc ( heap_size ));
179     char *vec_base = heap_block;
180 
181     if ( NULL != vec_base ) {
182         st_heap_block3 heap ( dealloc, heap_block, heap_size );
183 
184     //  put the padding before the array elements
185         if ( 0 != padding_size ) {
186             vec_base += padding_size;
187             __set_element_count ( vec_base, element_count );
188         }
189 
190     //  Construct the elements
191         __cxa_vec_ctor ( vec_base, element_count, element_size, constructor, destructor );
192         heap.release ();    // We're good!
193     }
194 
195     return vec_base;
196 }
197 
198 
199 // Given the (data) addresses of a destination and a source array, an
200 // element count and an element size, call the given copy constructor to
201 // copy each element from the source array to the destination array. The
202 // copy constructor's arguments are the destination address and source
203 // address, respectively. If an exception occurs, call the given destructor
204 // (if non-NULL) on each copied element and rethrow. If the destructor
205 // throws an exception, call terminate(). The constructor and or destructor
206 // pointers may be NULL. If either is NULL, no action is taken when it
207 // would have been called.
208 
__cxa_vec_cctor(void * dest_array,void * src_array,size_t element_count,size_t element_size,void (* constructor)(void *,void *),void (* destructor)(void *))209 void __cxa_vec_cctor( void*  dest_array, void*  src_array,
210     size_t element_count, size_t element_size,
211         void  (*constructor) (void*, void*), void  (*destructor)(void*) ) {
212 
213     if ( NULL != constructor ) {
214         size_t idx = 0;
215         char *src_ptr  = static_cast<char *>(src_array);
216         char *dest_ptr = static_cast<char *>(dest_array);
217         st_cxa_cleanup cleanup ( dest_array, idx, element_size, destructor );
218 
219         for ( idx = 0; idx < element_count;
220                     ++idx, src_ptr += element_size, dest_ptr += element_size )
221             constructor ( dest_ptr, src_ptr );
222         cleanup.release ();     // We're good!
223     }
224 }
225 
226 
227 // Given the (data) address of an array, not including any cookie padding,
228 // and the number and size of its elements, call the given constructor on
229 // each element. If the constructor throws an exception, call the given
230 // destructor for any already-constructed elements, and rethrow the
231 // exception. If the destructor throws an exception, call terminate(). The
232 // constructor and/or destructor pointers may be NULL. If either is NULL,
233 // no action is taken when it would have been called.
__cxa_vec_ctor(void * array_address,size_t element_count,size_t element_size,void (* constructor)(void *),void (* destructor)(void *))234 void __cxa_vec_ctor(
235     void*  array_address, size_t element_count, size_t element_size,
236        void (*constructor)(void*), void (*destructor)(void*) ) {
237 
238     if ( NULL != constructor ) {
239         size_t idx;
240         char *ptr = static_cast <char *> ( array_address );
241         st_cxa_cleanup cleanup ( array_address, idx, element_size, destructor );
242 
243     //  Construct the elements
244         for ( idx = 0; idx < element_count; ++idx, ptr += element_size )
245             constructor ( ptr );
246         cleanup.release ();     // We're good!
247     }
248 }
249 
250 // Given the (data) address of an array, the number of elements, and the
251 // size of its elements, call the given destructor on each element. If the
252 // destructor throws an exception, rethrow after destroying the remaining
253 // elements if possible. If the destructor throws a second exception, call
254 // terminate(). The destructor pointer may be NULL, in which case this
255 // routine does nothing.
__cxa_vec_dtor(void * array_address,size_t element_count,size_t element_size,void (* destructor)(void *))256 void __cxa_vec_dtor(
257     void*  array_address, size_t element_count, size_t element_size,
258        void (*destructor)(void*) ) {
259 
260     if ( NULL != destructor ) {
261         char *ptr = static_cast <char *> (array_address);
262         size_t idx = element_count;
263         st_cxa_cleanup cleanup ( array_address, idx, element_size, destructor );
264         {
265             st_terminate exception_guard (__cxa_uncaught_exception ());
266             ptr +=  element_count * element_size;   // one past the last element
267 
268             while ( idx-- > 0 ) {
269                 ptr -= element_size;
270                 destructor ( ptr );
271             }
272             exception_guard.release (); //  We're good !
273         }
274         cleanup.release ();     // We're still good!
275     }
276 }
277 
278 // Given the (data) address of an array, the number of elements, and the
279 // size of its elements, call the given destructor on each element. If the
280 // destructor throws an exception, call terminate(). The destructor pointer
281 // may be NULL, in which case this routine does nothing.
__cxa_vec_cleanup(void * array_address,size_t element_count,size_t element_size,void (* destructor)(void *))282 void __cxa_vec_cleanup( void* array_address, size_t element_count,
283         size_t element_size, void  (*destructor)(void*) ) {
284 
285     if ( NULL != destructor ) {
286         char *ptr = static_cast <char *> (array_address);
287         size_t idx = element_count;
288         st_terminate exception_guard;
289 
290         ptr += element_count * element_size;    // one past the last element
291         while ( idx-- > 0 ) {
292             ptr -= element_size;
293             destructor ( ptr );
294             }
295         exception_guard.release ();     // We're done!
296     }
297 }
298 
299 
300 // If the array_address is NULL, return immediately. Otherwise, given the
301 // (data) address of an array, the non-negative size of prefix padding for
302 // the cookie, and the size of its elements, call the given destructor on
303 // each element, using the cookie to determine the number of elements, and
304 // then delete the space by calling ::operator delete[](void *). If the
305 // destructor throws an exception, rethrow after (a) destroying the
306 // remaining elements, and (b) deallocating the storage. If the destructor
307 // throws a second exception, call terminate(). If padding_size is 0, the
308 // destructor pointer must be NULL. If the destructor pointer is NULL, no
309 // destructor call is to be made.
310 //
311 // The intent of this function is to permit an implementation to call this
312 // function when confronted with an expression of the form delete[] p in
313 // the source code, provided that the default deallocation function can be
314 // used. Therefore, the semantics of this function are consistent with
315 // those required by the standard. The requirement that the deallocation
316 // function be called even if the destructor throws an exception derives
317 // from the resolution to DR 353 to the C++ standard, which was adopted in
318 // April, 2003.
__cxa_vec_delete(void * array_address,size_t element_size,size_t padding_size,void (* destructor)(void *))319 void __cxa_vec_delete( void* array_address,
320         size_t element_size, size_t padding_size, void  (*destructor)(void*) ) {
321 
322     __cxa_vec_delete2 ( array_address, element_size, padding_size,
323                destructor, &::operator delete [] );
324 }
325 
326 
327 // Same as __cxa_vec_delete, except that the given function is used for
328 // deallocation instead of the default delete function. If dealloc throws
329 // an exception, the result is undefined. The dealloc pointer may not be
330 // NULL.
__cxa_vec_delete2(void * array_address,size_t element_size,size_t padding_size,void (* destructor)(void *),void (* dealloc)(void *))331 void __cxa_vec_delete2( void* array_address,
332         size_t element_size, size_t padding_size,
333         void  (*destructor)(void*), void  (*dealloc)(void*) ) {
334 
335     if ( NULL != array_address ) {
336         char *vec_base   = static_cast <char *> (array_address);
337         char *heap_block = vec_base - padding_size;
338         st_heap_block2 heap ( dealloc, heap_block );
339 
340         if ( 0 != padding_size && NULL != destructor ) // call the destructors
341             __cxa_vec_dtor ( array_address, __get_element_count ( vec_base ),
342                                     element_size, destructor );
343     }
344 }
345 
346 
347 // Same as __cxa_vec_delete, except that the given function is used for
348 // deallocation instead of the default delete function. The deallocation
349 // function takes both the object address and its size. If dealloc throws
350 // an exception, the result is undefined. The dealloc pointer may not be
351 // NULL.
__cxa_vec_delete3(void * array_address,size_t element_size,size_t padding_size,void (* destructor)(void *),void (* dealloc)(void *,size_t))352 void __cxa_vec_delete3( void* array_address,
353         size_t element_size, size_t padding_size,
354         void  (*destructor)(void*), void  (*dealloc) (void*, size_t)) {
355 
356     if ( NULL != array_address ) {
357         char *vec_base   = static_cast <char *> (array_address);
358         char *heap_block = vec_base - padding_size;
359         const size_t element_count = padding_size ? __get_element_count ( vec_base ) : 0;
360         const size_t heap_block_size = element_size * element_count + padding_size;
361         st_heap_block3 heap ( dealloc, heap_block, heap_block_size );
362 
363         if ( 0 != padding_size && NULL != destructor ) // call the destructors
364             __cxa_vec_dtor ( array_address, element_count, element_size, destructor );
365     }
366 }
367 
368 
369 }  // extern "C"
370 
371 }  // abi
372