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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[])
117 _LIBCXXABI_FUNC_VIS void *
__cxa_vec_new(size_t element_count,size_t element_size,size_t padding_size,void (* constructor)(void *),void (* destructor)(void *))118 __cxa_vec_new(size_t element_count, size_t element_size, size_t padding_size,
119               void (*constructor)(void *), void (*destructor)(void *)) {
120     return __cxa_vec_new2 ( element_count, element_size, padding_size,
121         constructor, destructor, &::operator new [], &::operator delete [] );
122 }
123 
124 
125 
126 // Given the number and size of elements for an array and the non-negative
127 // size of prefix padding for a cookie, allocate space (using alloc) for
128 // the array preceded by the specified padding, initialize the cookie if
129 // the padding is non-zero, and call the given constructor on each element.
130 // Return the address of the array proper, after the padding.
131 //
132 // If alloc throws an exception, rethrow the exception. If alloc returns
133 // NULL, return NULL. If the constructor throws an exception, call
134 // destructor for any already constructed elements, and rethrow the
135 // exception. If the destructor throws an exception, call std::terminate.
136 //
137 // The constructor may be NULL, in which case it must not be called. If the
138 // padding_size is zero, the destructor may be NULL; in that case it must
139 // not be called.
140 //
141 // Neither alloc nor dealloc may be NULL.
142 _LIBCXXABI_FUNC_VIS void *
__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 __cxa_vec_new2(size_t element_count, size_t element_size, size_t padding_size,
144                void (*constructor)(void *), void (*destructor)(void *),
145                void *(*alloc)(size_t), void (*dealloc)(void *)) {
146     const size_t heap_size = element_count * element_size + padding_size;
147     char * const heap_block = static_cast<char *> ( alloc ( heap_size ));
148     char *vec_base = heap_block;
149 
150     if ( NULL != vec_base ) {
151         st_heap_block2 heap ( dealloc, heap_block );
152 
153     //  put the padding before the array elements
154         if ( 0 != padding_size ) {
155             vec_base += padding_size;
156             __set_element_count ( vec_base, element_count );
157         }
158 
159     //  Construct the elements
160         __cxa_vec_ctor ( vec_base, element_count, element_size, constructor, destructor );
161         heap.release ();    // We're good!
162     }
163 
164     return vec_base;
165 }
166 
167 
168 // Same as __cxa_vec_new2 except that the deallocation function takes both
169 // the object address and its size.
170 _LIBCXXABI_FUNC_VIS void *
__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))171 __cxa_vec_new3(size_t element_count, size_t element_size, size_t padding_size,
172                void (*constructor)(void *), void (*destructor)(void *),
173                void *(*alloc)(size_t), void (*dealloc)(void *, size_t)) {
174     const size_t heap_size = element_count * element_size + padding_size;
175     char * const heap_block = static_cast<char *> ( alloc ( heap_size ));
176     char *vec_base = heap_block;
177 
178     if ( NULL != vec_base ) {
179         st_heap_block3 heap ( dealloc, heap_block, heap_size );
180 
181     //  put the padding before the array elements
182         if ( 0 != padding_size ) {
183             vec_base += padding_size;
184             __set_element_count ( vec_base, element_count );
185         }
186 
187     //  Construct the elements
188         __cxa_vec_ctor ( vec_base, element_count, element_size, constructor, destructor );
189         heap.release ();    // We're good!
190     }
191 
192     return vec_base;
193 }
194 
195 
196 // Given the (data) addresses of a destination and a source array, an
197 // element count and an element size, call the given copy constructor to
198 // copy each element from the source array to the destination array. The
199 // copy constructor's arguments are the destination address and source
200 // address, respectively. If an exception occurs, call the given destructor
201 // (if non-NULL) on each copied element and rethrow. If the destructor
202 // throws an exception, call terminate(). The constructor and or destructor
203 // pointers may be NULL. If either is NULL, no action is taken when it
204 // would have been called.
205 
__cxa_vec_cctor(void * dest_array,void * src_array,size_t element_count,size_t element_size,void (* constructor)(void *,void *),void (* destructor)(void *))206 _LIBCXXABI_FUNC_VIS void __cxa_vec_cctor(void *dest_array, void *src_array,
207                                          size_t element_count,
208                                          size_t element_size,
209                                          void (*constructor)(void *, void *),
210                                          void (*destructor)(void *)) {
211     if ( NULL != constructor ) {
212         size_t idx = 0;
213         char *src_ptr  = static_cast<char *>(src_array);
214         char *dest_ptr = static_cast<char *>(dest_array);
215         st_cxa_cleanup cleanup ( dest_array, idx, element_size, destructor );
216 
217         for ( idx = 0; idx < element_count;
218                     ++idx, src_ptr += element_size, dest_ptr += element_size )
219             constructor ( dest_ptr, src_ptr );
220         cleanup.release ();     // We're good!
221     }
222 }
223 
224 
225 // Given the (data) address of an array, not including any cookie padding,
226 // and the number and size of its elements, call the given constructor on
227 // each element. If the constructor throws an exception, call the given
228 // destructor for any already-constructed elements, and rethrow the
229 // exception. If the destructor throws an exception, call terminate(). The
230 // constructor and/or destructor pointers may be NULL. If either is NULL,
231 // no action is taken when it would have been called.
232 _LIBCXXABI_FUNC_VIS void
__cxa_vec_ctor(void * array_address,size_t element_count,size_t element_size,void (* constructor)(void *),void (* destructor)(void *))233 __cxa_vec_ctor(void *array_address, size_t element_count, size_t element_size,
234                void (*constructor)(void *), void (*destructor)(void *)) {
235     if ( NULL != constructor ) {
236         size_t idx;
237         char *ptr = static_cast <char *> ( array_address );
238         st_cxa_cleanup cleanup ( array_address, idx, element_size, destructor );
239 
240     //  Construct the elements
241         for ( idx = 0; idx < element_count; ++idx, ptr += element_size )
242             constructor ( ptr );
243         cleanup.release ();     // We're good!
244     }
245 }
246 
247 // Given the (data) address of an array, the number of elements, and the
248 // size of its elements, call the given destructor on each element. If the
249 // destructor throws an exception, rethrow after destroying the remaining
250 // elements if possible. If the destructor throws a second exception, call
251 // terminate(). The destructor pointer may be NULL, in which case this
252 // routine does nothing.
__cxa_vec_dtor(void * array_address,size_t element_count,size_t element_size,void (* destructor)(void *))253 _LIBCXXABI_FUNC_VIS void __cxa_vec_dtor(void *array_address,
254                                         size_t element_count,
255                                         size_t element_size,
256                                         void (*destructor)(void *)) {
257     if ( NULL != destructor ) {
258         char *ptr = static_cast <char *> (array_address);
259         size_t idx = element_count;
260         st_cxa_cleanup cleanup ( array_address, idx, element_size, destructor );
261         {
262             st_terminate exception_guard (__cxa_uncaught_exception ());
263             ptr +=  element_count * element_size;   // one past the last element
264 
265             while ( idx-- > 0 ) {
266                 ptr -= element_size;
267                 destructor ( ptr );
268             }
269             exception_guard.release (); //  We're good !
270         }
271         cleanup.release ();     // We're still good!
272     }
273 }
274 
275 // Given the (data) address of an array, the number of elements, and the
276 // size of its elements, call the given destructor on each element. If the
277 // destructor throws an exception, call terminate(). The destructor pointer
278 // 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 *))279 _LIBCXXABI_FUNC_VIS void __cxa_vec_cleanup(void *array_address,
280                                            size_t element_count,
281                                            size_t element_size,
282                                            void (*destructor)(void *)) {
283     if ( NULL != destructor ) {
284         char *ptr = static_cast <char *> (array_address);
285         size_t idx = element_count;
286         st_terminate exception_guard;
287 
288         ptr += element_count * element_size;    // one past the last element
289         while ( idx-- > 0 ) {
290             ptr -= element_size;
291             destructor ( ptr );
292             }
293         exception_guard.release ();     // We're done!
294     }
295 }
296 
297 
298 // If the array_address is NULL, return immediately. Otherwise, given the
299 // (data) address of an array, the non-negative size of prefix padding for
300 // the cookie, and the size of its elements, call the given destructor on
301 // each element, using the cookie to determine the number of elements, and
302 // then delete the space by calling ::operator delete[](void *). If the
303 // destructor throws an exception, rethrow after (a) destroying the
304 // remaining elements, and (b) deallocating the storage. If the destructor
305 // throws a second exception, call terminate(). If padding_size is 0, the
306 // destructor pointer must be NULL. If the destructor pointer is NULL, no
307 // destructor call is to be made.
308 //
309 // The intent of this function is to permit an implementation to call this
310 // function when confronted with an expression of the form delete[] p in
311 // the source code, provided that the default deallocation function can be
312 // used. Therefore, the semantics of this function are consistent with
313 // those required by the standard. The requirement that the deallocation
314 // function be called even if the destructor throws an exception derives
315 // from the resolution to DR 353 to the C++ standard, which was adopted in
316 // April, 2003.
__cxa_vec_delete(void * array_address,size_t element_size,size_t padding_size,void (* destructor)(void *))317 _LIBCXXABI_FUNC_VIS void __cxa_vec_delete(void *array_address,
318                                           size_t element_size,
319                                           size_t padding_size,
320                                           void (*destructor)(void *)) {
321     __cxa_vec_delete2 ( array_address, element_size, padding_size,
322                destructor, &::operator delete [] );
323 }
324 
325 // Same as __cxa_vec_delete, except that the given function is used for
326 // deallocation instead of the default delete function. If dealloc throws
327 // an exception, the result is undefined. The dealloc pointer may not be
328 // NULL.
329 _LIBCXXABI_FUNC_VIS void
__cxa_vec_delete2(void * array_address,size_t element_size,size_t padding_size,void (* destructor)(void *),void (* dealloc)(void *))330 __cxa_vec_delete2(void *array_address, size_t element_size, size_t padding_size,
331                   void (*destructor)(void *), void (*dealloc)(void *)) {
332     if ( NULL != array_address ) {
333         char *vec_base   = static_cast <char *> (array_address);
334         char *heap_block = vec_base - padding_size;
335         st_heap_block2 heap ( dealloc, heap_block );
336 
337         if ( 0 != padding_size && NULL != destructor ) // call the destructors
338             __cxa_vec_dtor ( array_address, __get_element_count ( vec_base ),
339                                     element_size, destructor );
340     }
341 }
342 
343 
344 // Same as __cxa_vec_delete, except that the given function is used for
345 // deallocation instead of the default delete function. The deallocation
346 // function takes both the object address and its size. If dealloc throws
347 // an exception, the result is undefined. The dealloc pointer may not be
348 // NULL.
349 _LIBCXXABI_FUNC_VIS void
__cxa_vec_delete3(void * array_address,size_t element_size,size_t padding_size,void (* destructor)(void *),void (* dealloc)(void *,size_t))350 __cxa_vec_delete3(void *array_address, size_t element_size, size_t padding_size,
351                   void (*destructor)(void *), void (*dealloc)(void *, size_t)) {
352     if ( NULL != array_address ) {
353         char *vec_base   = static_cast <char *> (array_address);
354         char *heap_block = vec_base - padding_size;
355         const size_t element_count = padding_size ? __get_element_count ( vec_base ) : 0;
356         const size_t heap_block_size = element_size * element_count + padding_size;
357         st_heap_block3 heap ( dealloc, heap_block, heap_block_size );
358 
359         if ( 0 != padding_size && NULL != destructor ) // call the destructors
360             __cxa_vec_dtor ( array_address, element_count, element_size, destructor );
361     }
362 }
363 
364 
365 }  // extern "C"
366 
367 }  // abi
368