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heap.cfa @ 2bfc6b2

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Last change on this file since 2bfc6b2 was b6830d74, checked in by Thierry Delisle <tdelisle@…>, 6 years ago
First pass of comment on heap.cfa
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1	// #comment TD : this file uses both spaces and tabs for indentation
2
3	//
4	// Cforall Version 1.0.0 Copyright (C) 2017 University of Waterloo
5	//
6	// The contents of this file are covered under the licence agreement in the
7	// file "LICENCE" distributed with Cforall.
8	//
9	// heap.c --
10	//
11	// Author : Peter A. Buhr
12	// Created On : Tue Dec 19 21:58:35 2017
13	// Last Modified By : Peter A. Buhr
14	// Last Modified On : Sat Aug 11 08:22:16 2018
15	// Update Count : 495
16	//
17
18	#include <unistd.h> // sbrk, sysconf
19	#include <stdbool.h> // true, false
20	#include <stdio.h> // snprintf, fileno
21	#include <errno.h> // errno
22	extern "C" {
23	#include <sys/mman.h> // mmap, munmap
24	} // extern "C"
25
26	// #comment TD : Many of these should be merged into math I believe
27	#include "bits/align.hfa" // libPow2
28	#include "bits/defs.hfa" // likely, unlikely
29	#include "bits/locks.hfa" // __spinlock_t
30	#include "startup.hfa" // STARTUP_PRIORITY_MEMORY
31	#include "stdlib.hfa" // bsearchl
32	#include "malloc.h"
33
34
35	enum {
36	__CFA_DEFAULT_MMAP_START__ = (512 * 1024 + 1),
37	__CFA_DEFAULT_HEAP_EXPANSION__ = (1 * 1024 * 1024),
38	};
39
40	size_t default_mmap_start() __attribute__(( weak )) {
41	return __CFA_DEFAULT_MMAP_START__;
42	} // default_mmap_start
43
44	size_t default_heap_expansion() __attribute__(( weak )) {
45	return __CFA_DEFAULT_HEAP_EXPANSION__;
46	} // default_heap_expansion
47
48
49	// supported mallopt options
50	#ifndef M_MMAP_THRESHOLD
51	#define M_MMAP_THRESHOLD (-1)
52	#endif // M_TOP_PAD
53	#ifndef M_TOP_PAD
54	#define M_TOP_PAD (-2)
55	#endif // M_TOP_PAD
56
57	#define FASTLOOKUP
58	#define __STATISTICS__
59
60	#define SPINLOCK 0
61	#define LOCKFREE 1
62	#define BUCKETLOCK SPINLOCK
63	#if BUCKETLOCK == LOCKFREE
64	#include <uStackLF.h>
65	#endif // LOCKFREE
66
67	// #comment TD : This defined is significantly different from the __ALIGN__ define from locks.hfa
68	#define ALIGN 16
69
70	// enum { NoBucketSizes = 93, // number of buckets sizes
71	// #ifdef FASTLOOKUP
72	// LookupSizes = 65536, // number of fast lookup sizes
73	// #endif // FASTLOOKUP
74	// };
75	#define NoBucketSizes 93 // number of buckets sizes
76	#ifdef FASTLOOKUP
77	#define LookupSizes 65536 // number of fast lookup sizes
78	#endif // FASTLOOKUP
79
80
81	static bool traceHeap = false;
82
83	inline bool traceHeap() {
84	return traceHeap;
85	} // traceHeap
86
87	bool traceHeapOn() {
88	bool temp = traceHeap;
89	traceHeap = true;
90	return temp;
91	} // traceHeapOn
92
93	bool traceHeapOff() {
94	bool temp = traceHeap;
95	traceHeap = false;
96	return temp;
97	} // traceHeapOff
98
99
100	static bool checkFree = false;
101
102	inline bool checkFree() {
103	return checkFree;
104	} // checkFree
105
106	bool checkFreeOn() {
107	bool temp = checkFree;
108	checkFree = true;
109	return temp;
110	} // checkFreeOn
111
112	bool checkFreeOff() {
113	bool temp = checkFree;
114	checkFree = false;
115	return temp;
116	} // checkFreeOff
117
118
119	// static bool traceHeapTerm = false;
120
121	// inline bool traceHeapTerm() {
122	// return traceHeapTerm;
123	// } // traceHeapTerm
124
125	// bool traceHeapTermOn() {
126	// bool temp = traceHeapTerm;
127	// traceHeapTerm = true;
128	// return temp;
129	// } // traceHeapTermOn
130
131	// bool traceHeapTermOff() {
132	// bool temp = traceHeapTerm;
133	// traceHeapTerm = false;
134	// return temp;
135	// } // traceHeapTermOff
136
137
138	#ifdef __CFA_DEBUG__
139	static unsigned int allocFree; // running total of allocations minus frees
140
141	static void checkUnfreed() {
142	if ( allocFree != 0 ) {
143	// DO NOT USE STREAMS AS THEY MAY BE UNAVAILABLE AT THIS POINT.
144	// char helpText[512];
145	// int len = snprintf( helpText, sizeof(helpText), "CFA warning (UNIX pid:%ld) : program terminating with %u(0x%x) bytes of storage allocated but not freed.\n"
146	// "Possible cause is unfreed storage allocated by the program or system/library routines called from the program.\n",
147	// (long int)getpid(), allocFree, allocFree ); // always print the UNIX pid
148	// __cfaabi_dbg_bits_write( helpText, len );
149	} // if
150	} // checkUnfreed
151
152	extern "C" {
153	void heapAppStart() { // called by __cfaabi_appready_startup
154	allocFree = 0;
155	} // heapAppStart
156
157	void heapAppStop() { // called by __cfaabi_appready_startdown
158	fclose( stdin ); fclose( stdout );
159	checkUnfreed();
160	} // heapAppStop
161	} // extern "C"
162	#endif // __CFA_DEBUG__
163
164
165	struct HeapManager {
166	// struct FreeHeader; // forward declaration
167
168	struct Storage {
169	struct Header { // header
170	union Kind {
171	struct RealHeader {
172	union {
173	// #comment TD : this code use byte size but the comment uses bit size
174
175	struct { // 32-bit word => 64-bit header, 64-bit word => 128-bit header
176	#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ && __SIZEOF_POINTER__ == 4
177	uint32_t padding; // unused, force home/blocksize to overlay alignment in fake header
178	#endif // __ORDER_BIG_ENDIAN__ && __U_WORDSIZE__ == 32
179
180	union {
181	// FreeHeader * home; // allocated block points back to home locations (must overlay alignment)
182	void * home; // allocated block points back to home locations (must overlay alignment)
183	size_t blockSize; // size for munmap (must overlay alignment)
184	#if BUCKLOCK == SPINLOCK
185	Storage * next; // freed block points next freed block of same size
186	#endif // SPINLOCK
187	};
188
189	#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ && __SIZEOF_POINTER__ == 4
190	uint32_t padding; // unused, force home/blocksize to overlay alignment in fake header
191	#endif // __ORDER_LITTLE_ENDIAN__ && __U_WORDSIZE__ == 32
192
193	};
194
195	// #comment TD : C++ code
196	#if BUCKLOCK == LOCKFREE
197	Stack<Storage>::Link next; // freed block points next freed block of same size (double-wide)
198	#endif // LOCKFREE
199	};
200	} real; // RealHeader
201	struct FakeHeader {
202	#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
203	uint32_t alignment; // low-order bits of home/blockSize used for tricks
204	#endif // __ORDER_LITTLE_ENDIAN__
205
206	uint32_t offset;
207
208	#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
209	uint32_t alignment; // low-order bits of home/blockSize used for tricks
210	#endif // __ORDER_BIG_ENDIAN__
211	} fake; // FakeHeader
212	} kind; // Kind
213	} header; // Header
214	char pad[ALIGN - sizeof( Header )];
215	char data[0]; // storage
216	}; // Storage
217
218	static_assert( ALIGN >= sizeof( Storage ), "ALIGN < sizeof( Storage )" );
219
220	struct FreeHeader {
221	#if BUCKLOCK == SPINLOCK
222	__spinlock_t lock; // must be first field for alignment
223	Storage * freeList;
224	#elif BUCKLOCK == LOCKFREE
225	// #comment TD : C++ code
226	StackLF<Storage> freeList;
227	#else
228	#error undefined lock type for bucket lock
229	#endif // SPINLOCK
230	size_t blockSize; // size of allocations on this list
231	}; // FreeHeader
232
233	// must be first fields for alignment
234	__spinlock_t extlock; // protects allocation-buffer extension
235	FreeHeader freeLists[NoBucketSizes]; // buckets for different allocation sizes
236
237	void * heapBegin; // start of heap
238	void * heapEnd; // logical end of heap
239	size_t heapRemaining; // amount of storage not allocated in the current chunk
240	}; // HeapManager
241
242	static inline size_t getKey( const HeapManager.FreeHeader & freeheader ) { return freeheader.blockSize; }
243	// statically allocated variables => zero filled.
244
245
246	static size_t pageSize; // architecture pagesize
247	static size_t heapExpand; // sbrk advance
248	static size_t mmapStart; // cross over point for mmap
249	static unsigned int maxBucketsUsed; // maximum number of buckets in use
250
251	// #comment TD : This array is not const but it feels like it should be
252	// Powers of 2 are common allocation sizes, so make powers of 2 generate the minimum required size.
253	static unsigned int bucketSizes[NoBucketSizes] @= { // different bucket sizes
254	16, 32, 48, 64,
255	64 + sizeof(HeapManager.Storage), 96, 112, 128, 128 + sizeof(HeapManager.Storage), 160, 192, 224,
256	256 + sizeof(HeapManager.Storage), 320, 384, 448, 512 + sizeof(HeapManager.Storage), 640, 768, 896,
257	1_024 + sizeof(HeapManager.Storage), 1_536, 2_048 + sizeof(HeapManager.Storage), 2_560, 3_072, 3_584, 4_096 + sizeof(HeapManager.Storage), 6_144,
258	8_192 + sizeof(HeapManager.Storage), 9_216, 10_240, 11_264, 12_288, 13_312, 14_336, 15_360,
259	16_384 + sizeof(HeapManager.Storage), 18_432, 20_480, 22_528, 24_576, 26_624, 28_672, 30_720,
260	32_768 + sizeof(HeapManager.Storage), 36_864, 40_960, 45_056, 49_152, 53_248, 57_344, 61_440,
261	65_536 + sizeof(HeapManager.Storage), 73_728, 81_920, 90_112, 98_304, 106_496, 114_688, 122_880,
262	131_072 + sizeof(HeapManager.Storage), 147_456, 163_840, 180_224, 196_608, 212_992, 229_376, 245_760,
263	262_144 + sizeof(HeapManager.Storage), 294_912, 327_680, 360_448, 393_216, 425_984, 458_752, 491_520,
264	524_288 + sizeof(HeapManager.Storage), 655_360, 786_432, 917_504, 1_048_576 + sizeof(HeapManager.Storage), 1_179_648, 1_310_720, 1_441_792,
265	1_572_864, 1_703_936, 1_835_008, 1_966_080, 2_097_152 + sizeof(HeapManager.Storage), 2_621_440, 3_145_728, 3_670_016,
266	4_194_304 + sizeof(HeapManager.Storage)
267	};
268	#ifdef FASTLOOKUP
269	static unsigned char lookup[LookupSizes]; // O(1) lookup for small sizes
270	#endif // FASTLOOKUP
271	static int mmapFd = -1; // fake or actual fd for anonymous file
272
273
274	#ifdef __CFA_DEBUG__
275	static bool heapBoot = 0; // detect recursion during boot
276	#endif // __CFA_DEBUG__
277	static HeapManager heapManager __attribute__(( aligned (128) )) @= {}; // size of cache line to prevent false sharing
278
279	// #comment TD : The return type of this function should be commented
280	static inline bool setMmapStart( size_t value ) {
281	if ( value < pageSize \|\| bucketSizes[NoBucketSizes - 1] < value ) return true;
282	mmapStart = value; // set global
283
284	// find the closest bucket size less than or equal to the mmapStart size
285	maxBucketsUsed = bsearchl( (unsigned int)mmapStart, bucketSizes, NoBucketSizes ); // binary search
286	assert( maxBucketsUsed < NoBucketSizes ); // subscript failure ?
287	assert( mmapStart <= bucketSizes[maxBucketsUsed] ); // search failure ?
288	return false;
289	} // setMmapStart
290
291
292	static void ?{}( HeapManager & manager ) with ( manager ) {
293	pageSize = sysconf( _SC_PAGESIZE );
294
295	for ( unsigned int i = 0; i < NoBucketSizes; i += 1 ) { // initialize the free lists
296	freeLists[i].blockSize = bucketSizes[i];
297	} // for
298
299	#ifdef FASTLOOKUP
300	unsigned int idx = 0;
301	for ( unsigned int i = 0; i < LookupSizes; i += 1 ) {
302	if ( i > bucketSizes[idx] ) idx += 1;
303	lookup[i] = idx;
304	} // for
305	#endif // FASTLOOKUP
306
307	if ( setMmapStart( default_mmap_start() ) ) {
308	abort( "HeapManager : internal error, mmap start initialization failure." );
309	} // if
310	heapExpand = default_heap_expansion();
311
312	char * End = (char *)sbrk( 0 );
313	sbrk( (char *)libCeiling( (long unsigned int)End, libAlign() ) - End ); // move start of heap to multiple of alignment
314	heapBegin = heapEnd = sbrk( 0 ); // get new start point
315	} // HeapManager
316
317
318	static void ^?{}( HeapManager & ) {
319	#ifdef __STATISTICS__
320	// if ( traceHeapTerm() ) {
321	// printStats();
322	// if ( checkfree() ) checkFree( heapManager, true );
323	// } // if
324	#endif // __STATISTICS__
325	} // ~HeapManager
326
327
328	static void memory_startup( void ) __attribute__(( constructor( STARTUP_PRIORITY_MEMORY ) ));
329	void memory_startup( void ) {
330	#ifdef __CFA_DEBUG__
331	if ( unlikely( heapBoot ) ) { // check for recursion during system boot
332	// DO NOT USE STREAMS AS THEY MAY BE UNAVAILABLE AT THIS POINT.
333	abort( "boot() : internal error, recursively invoked during system boot." );
334	} // if
335	heapBoot = true;
336	#endif // __CFA_DEBUG__
337
338	// #comment TD : This assertion seems redundent with the above code
339	assert( heapManager.heapBegin == 0 );
340	heapManager{};
341	} // memory_startup
342
343	static void memory_shutdown( void ) __attribute__(( destructor( STARTUP_PRIORITY_MEMORY ) ));
344	void memory_shutdown( void ) {
345	^heapManager{};
346	} // memory_shutdown
347
348
349	#ifdef __STATISTICS__
350	static unsigned long long int mmap_storage; // heap statistics counters
351	static unsigned int mmap_calls;
352	static unsigned long long int munmap_storage;
353	static unsigned int munmap_calls;
354	static unsigned long long int sbrk_storage;
355	static unsigned int sbrk_calls;
356	static unsigned long long int malloc_storage;
357	static unsigned int malloc_calls;
358	static unsigned long long int free_storage;
359	static unsigned int free_calls;
360	static unsigned long long int calloc_storage;
361	static unsigned int calloc_calls;
362	static unsigned long long int memalign_storage;
363	static unsigned int memalign_calls;
364	static unsigned long long int cmemalign_storage;
365	static unsigned int cmemalign_calls;
366	static unsigned long long int realloc_storage;
367	static unsigned int realloc_calls;
368
369	static int statfd; // statistics file descriptor (changed by malloc_stats_fd)
370
371
372	// Use "write" because streams may be shutdown when calls are made.
373	static void printStats() {
374	char helpText[512];
375	__cfaabi_dbg_bits_print_buffer( helpText, sizeof(helpText),
376	"\nHeap statistics:\n"
377	" malloc: calls %u / storage %llu\n"
378	" calloc: calls %u / storage %llu\n"
379	" memalign: calls %u / storage %llu\n"
380	" cmemalign: calls %u / storage %llu\n"
381	" realloc: calls %u / storage %llu\n"
382	" free: calls %u / storage %llu\n"
383	" mmap: calls %u / storage %llu\n"
384	" munmap: calls %u / storage %llu\n"
385	" sbrk: calls %u / storage %llu\n",
386	malloc_calls, malloc_storage,
387	calloc_calls, calloc_storage,
388	memalign_calls, memalign_storage,
389	cmemalign_calls, cmemalign_storage,
390	realloc_calls, realloc_storage,
391	free_calls, free_storage,
392	mmap_calls, mmap_storage,
393	munmap_calls, munmap_storage,
394	sbrk_calls, sbrk_storage
395	);
396	} // printStats
397
398	// #comment TD : Why do we have this?
399	static int printStatsXML( FILE * stream ) {
400	char helpText[512];
401	int len = snprintf( helpText, sizeof(helpText),
402	"<malloc version=\"1\">\n"
403	"<heap nr=\"0\">\n"
404	"<sizes>\n"
405	"</sizes>\n"
406	"<total type=\"malloc\" count=\"%u\" size=\"%llu\"/>\n"
407	"<total type=\"calloc\" count=\"%u\" size=\"%llu\"/>\n"
408	"<total type=\"memalign\" count=\"%u\" size=\"%llu\"/>\n"
409	"<total type=\"cmemalign\" count=\"%u\" size=\"%llu\"/>\n"
410	"<total type=\"realloc\" count=\"%u\" size=\"%llu\"/>\n"
411	"<total type=\"free\" count=\"%u\" size=\"%llu\"/>\n"
412	"<total type=\"mmap\" count=\"%u\" size=\"%llu\"/>\n"
413	"<total type=\"munmap\" count=\"%u\" size=\"%llu\"/>\n"
414	"<total type=\"sbrk\" count=\"%u\" size=\"%llu\"/>\n"
415	"</malloc>",
416	malloc_calls, malloc_storage,
417	calloc_calls, calloc_storage,
418	memalign_calls, memalign_storage,
419	cmemalign_calls, cmemalign_storage,
420	realloc_calls, realloc_storage,
421	free_calls, free_storage,
422	mmap_calls, mmap_storage,
423	munmap_calls, munmap_storage,
424	sbrk_calls, sbrk_storage
425	);
426	return write( fileno( stream ), helpText, len ); // -1 => error
427	} // printStatsXML
428	#endif // __STATISTICS__
429
430	// #comment TD : Is this the samething as Out-of-Memory?
431	static inline void noMemory() {
432	abort( "Heap memory exhausted at %zu bytes.\n"
433	"Possible cause is very large memory allocation and/or large amount of unfreed storage allocated by the program or system/library routines.",
434	((char )(sbrk( 0 )) - (char )(heapManager.heapBegin)) );
435	} // noMemory
436
437
438	static inline void checkAlign( size_t alignment ) {
439	if ( alignment < sizeof(void *) \|\| ! libPow2( alignment ) ) {
440	abort( "Alignment %zu for memory allocation is less than sizeof(void *) and/or not a power of 2.", alignment );
441	} // if
442	} // checkAlign
443
444
445	static inline bool setHeapExpand( size_t value ) {
446	if ( heapExpand < pageSize ) return true;
447	heapExpand = value;
448	return false;
449	} // setHeapExpand
450
451
452	static inline void checkHeader( bool check, const char * name, void * addr ) {
453	if ( unlikely( check ) ) { // bad address ?
454	abort( "Attempt to %s storage %p with address outside the heap.\n"
455	"Possible cause is duplicate free on same block or overwriting of memory.",
456	name, addr );
457	} // if
458	} // checkHeader
459
460	// #comment TD : function should be commented and/or have a more evocative name
461	// this isn't either a check or a constructor which is what I would expect this function to be
462	static inline void fakeHeader( HeapManager.Storage.Header *& header, size_t & size, size_t & alignment ) {
463	if ( unlikely( (header->kind.fake.alignment & 1) == 1 ) ) { // fake header ?
464	size_t offset = header->kind.fake.offset;
465	alignment = header->kind.fake.alignment & -2; // remove flag from value
466	#ifdef __CFA_DEBUG__
467	checkAlign( alignment ); // check alignment
468	#endif // __CFA_DEBUG__
469	header = (HeapManager.Storage.Header )((char )header - offset);
470	} // if
471	} // fakeHeader
472
473	// #comment TD : Why is this a define
474	#define headerAddr( addr ) ((HeapManager.Storage.Header )( (char )addr - sizeof(HeapManager.Storage) ))
475
476	static inline bool headers( const char * name, void * addr, HeapManager.Storage.Header & header, HeapManager.FreeHeader & freeElem, size_t & size, size_t & alignment ) with ( heapManager ) {
477	header = headerAddr( addr );
478
479	if ( unlikely( heapEnd < addr ) ) { // mmapped ?
480	fakeHeader( header, size, alignment );
481	size = header->kind.real.blockSize & -3; // mmap size
482	return true;
483	} // if
484
485	#ifdef __CFA_DEBUG__
486	checkHeader( addr < heapBegin \|\| header < (HeapManager.Storage.Header *)heapBegin, name, addr ); // bad low address ?
487	#endif // __CFA_DEBUG__
488
489	// #comment TD : This code looks weird...
490	// It's called as the first statement of both branches of the last if, with the same parameters in all cases
491
492	// header may be safe to dereference
493	fakeHeader( header, size, alignment );
494	#ifdef __CFA_DEBUG__
495	checkHeader( header < (HeapManager.Storage.Header )heapBegin \|\| (HeapManager.Storage.Header )heapEnd < header, name, addr ); // bad address ? (offset could be + or -)
496	#endif // __CFA_DEBUG__
497
498	freeElem = (HeapManager.FreeHeader *)((size_t)header->kind.real.home & -3);
499	#ifdef __CFA_DEBUG__
500	if ( freeElem < &freeLists[0] \|\| &freeLists[NoBucketSizes] <= freeElem ) {
501	abort( "Attempt to %s storage %p with corrupted header.\n"
502	"Possible cause is duplicate free on same block or overwriting of header information.",
503	name, addr );
504	} // if
505	#endif // __CFA_DEBUG__
506	size = freeElem->blockSize;
507	return false;
508	} // headers
509
510
511	static inline void * extend( size_t size ) with ( heapManager ) {
512	lock( extlock __cfaabi_dbg_ctx2 );
513	ptrdiff_t rem = heapRemaining - size;
514	if ( rem < 0 ) {
515	// If the size requested is bigger than the current remaining storage, increase the size of the heap.
516
517	size_t increase = libCeiling( size > heapExpand ? size : heapExpand, libAlign() );
518	if ( sbrk( increase ) == (void *)-1 ) {
519	unlock( extlock );
520	errno = ENOMEM;
521	return 0;
522	} // if
523	#ifdef __STATISTICS__
524	sbrk_calls += 1;
525	sbrk_storage += increase;
526	#endif // __STATISTICS__
527	#ifdef __CFA_DEBUG__
528	// Set new memory to garbage so subsequent uninitialized usages might fail.
529	memset( (char *)heapEnd + heapRemaining, '\377', increase );
530	#endif // __CFA_DEBUG__
531	rem = heapRemaining + increase - size;
532	} // if
533
534	HeapManager.Storage * block = (HeapManager.Storage *)heapEnd;
535	heapRemaining = rem;
536	heapEnd = (char *)heapEnd + size;
537	unlock( extlock );
538	return block;
539	} // extend
540
541
542	static inline void * doMalloc( size_t size ) with ( heapManager ) {
543	HeapManager.Storage * block;
544
545	// Look up size in the size list. Make sure the user request includes space for the header that must be allocated
546	// along with the block and is a multiple of the alignment size.
547
548	size_t tsize = size + sizeof(HeapManager.Storage);
549	if ( likely( tsize < mmapStart ) ) { // small size => sbrk
550	HeapManager.FreeHeader * freeElem =
551	#ifdef FASTLOOKUP
552	tsize < LookupSizes ? &freeLists[lookup[tsize]] :
553	#endif // FASTLOOKUP
554	bsearchl( tsize, freeLists, (size_t)maxBucketsUsed ); // binary search
555	assert( freeElem <= &freeLists[maxBucketsUsed] ); // subscripting error ?
556	assert( tsize <= freeElem->blockSize ); // search failure ?
557	tsize = freeElem->blockSize; // total space needed for request
558
559	// Spin until the lock is acquired for this particular size of block.
560
561	#if defined( SPINLOCK )
562	lock( freeElem->lock __cfaabi_dbg_ctx2 );
563	block = freeElem->freeList; // remove node from stack
564	#else
565	block = freeElem->freeList.pop();
566	#endif // SPINLOCK
567	if ( unlikely( block == 0 ) ) { // no free block ?
568	#if defined( SPINLOCK )
569	unlock( freeElem->lock );
570	#endif // SPINLOCK
571	// Freelist for that size was empty, so carve it out of the heap if there's enough left, or get some more
572	// and then carve it off.
573
574	block = (HeapManager.Storage *)extend( tsize ); // mutual exclusion on call
575	if ( unlikely( block == 0 ) ) return 0;
576	#if defined( SPINLOCK )
577	} else {
578	freeElem->freeList = block->header.kind.real.next;
579	unlock( freeElem->lock );
580	#endif // SPINLOCK
581	} // if
582
583	block->header.kind.real.home = freeElem; // pointer back to free list of apropriate size
584	} else { // large size => mmap
585	tsize = libCeiling( tsize, pageSize ); // must be multiple of page size
586	#ifdef __STATISTICS__
587	__atomic_add_fetch( &mmap_calls, 1, __ATOMIC_SEQ_CST );
588	__atomic_add_fetch( &mmap_storage, tsize, __ATOMIC_SEQ_CST );
589	#endif // __STATISTICS__
590	block = (HeapManager.Storage *)mmap( 0, tsize, PROT_READ \| PROT_WRITE, MAP_PRIVATE \| MAP_ANONYMOUS, mmapFd, 0 );
591	if ( block == (HeapManager.Storage *)MAP_FAILED ) {
592	// Do not call strerror( errno ) as it may call malloc.
593	abort( "(HeapManager &)0x%p.doMalloc() : internal error, mmap failure, size:%zu error:%d.", &heapManager, tsize, errno );
594	} // if
595	#ifdef __CFA_DEBUG__
596	// Set new memory to garbage so subsequent uninitialized usages might fail.
597	memset( block, '\377', tsize );
598	#endif // __CFA_DEBUG__
599	block->header.kind.real.blockSize = tsize; // storage size for munmap
600	} // if
601
602	void * area = &(block->data); // adjust off header to user bytes
603
604	#ifdef __CFA_DEBUG__
605	assert( ((uintptr_t)area & (libAlign() - 1)) == 0 ); // minimum alignment ?
606	__atomic_add_fetch( &allocFree, tsize, __ATOMIC_SEQ_CST );
607	if ( traceHeap() ) {
608	enum { BufferSize = 64 };
609	char helpText[BufferSize];
610	int len = snprintf( helpText, BufferSize, "%p = Malloc( %zu ) (allocated %zu)\n", area, size, tsize );
611	// int len = snprintf( helpText, BufferSize, "Malloc %p %zu\n", area, size );
612	__cfaabi_dbg_bits_write( helpText, len );
613	} // if
614	#endif // __CFA_DEBUG__
615
616	return area;
617	} // doMalloc
618
619
620	static inline void doFree( void * addr ) with ( heapManager ) {
621	#ifdef __CFA_DEBUG__
622	if ( unlikely( heapManager.heapBegin == 0 ) ) {
623	abort( "doFree( %p ) : internal error, called before heap is initialized.", addr );
624	} // if
625	#endif // __CFA_DEBUG__
626
627	HeapManager.Storage.Header * header;
628	HeapManager.FreeHeader * freeElem;
629	size_t size, alignment; // not used (see realloc)
630
631	if ( headers( "free", addr, header, freeElem, size, alignment ) ) { // mmapped ?
632	#ifdef __STATISTICS__
633	__atomic_add_fetch( &munmap_calls, 1, __ATOMIC_SEQ_CST );
634	__atomic_add_fetch( &munmap_storage, size, __ATOMIC_SEQ_CST );
635	#endif // __STATISTICS__
636	if ( munmap( header, size ) == -1 ) {
637	#ifdef __CFA_DEBUG__
638	abort( "Attempt to deallocate storage %p not allocated or with corrupt header.\n"
639	"Possible cause is invalid pointer.",
640	addr );
641	#endif // __CFA_DEBUG__
642	} // if
643	} else {
644	#ifdef __CFA_DEBUG__
645	// Set free memory to garbage so subsequent usages might fail.
646	memset( ((HeapManager.Storage *)header)->data, '\377', freeElem->blockSize - sizeof( HeapManager.Storage ) );
647	#endif // __CFA_DEBUG__
648
649	#ifdef __STATISTICS__
650	free_storage += size;
651	#endif // __STATISTICS__
652	#if defined( SPINLOCK )
653	lock( freeElem->lock __cfaabi_dbg_ctx2 ); // acquire spin lock
654	header->kind.real.next = freeElem->freeList; // push on stack
655	freeElem->freeList = (HeapManager.Storage *)header;
656	unlock( freeElem->lock ); // release spin lock
657	#else
658	freeElem->freeList.push( (HeapManager.Storage )header );
659	#endif // SPINLOCK
660	} // if
661
662	#ifdef __CFA_DEBUG__
663	__atomic_add_fetch( &allocFree, -size, __ATOMIC_SEQ_CST );
664	if ( traceHeap() ) {
665	char helpText[64];
666	int len = snprintf( helpText, sizeof(helpText), "Free( %p ) size:%zu\n", addr, size );
667	__cfaabi_dbg_bits_write( helpText, len );
668	} // if
669	#endif // __CFA_DEBUG__
670	} // doFree
671
672
673	size_t checkFree( HeapManager & manager ) with ( manager ) {
674	size_t total = 0;
675	#ifdef __STATISTICS__
676	__cfaabi_dbg_bits_acquire();
677	__cfaabi_dbg_bits_print_nolock( "\nBin lists (bin size : free blocks on list)\n" );
678	#endif // __STATISTICS__
679	for ( unsigned int i = 0; i < maxBucketsUsed; i += 1 ) {
680	size_t size = freeLists[i].blockSize;
681	#ifdef __STATISTICS__
682	unsigned int N = 0;
683	#endif // __STATISTICS__
684
685	#if defined( SPINLOCK )
686	for ( HeapManager.Storage * p = freeLists[i].freeList; p != 0; p = p->header.kind.real.next ) {
687	#else
688	for ( HeapManager.Storage * p = freeLists[i].freeList.top(); p != 0; p = p->header.kind.real.next.top ) {
689	#endif // SPINLOCK
690	total += size;
691	#ifdef __STATISTICS__
692	N += 1;
693	#endif // __STATISTICS__
694	} // for
695
696	#ifdef __STATISTICS__
697	__cfaabi_dbg_bits_print_nolock( "%7zu, %-7u ", size, N );
698	if ( (i + 1) % 8 == 0 ) __cfaabi_dbg_bits_print_nolock( "\n" );
699	#endif // __STATISTICS__
700	} // for
701	#ifdef __STATISTICS__
702	__cfaabi_dbg_bits_print_nolock( "\ntotal free blocks:%zu\n", total );
703	__cfaabi_dbg_bits_release();
704	#endif // __STATISTICS__
705	return (char )heapEnd - (char )heapBegin - total;
706	} // checkFree
707
708	// #comment TD : This is not a good name, plus this feels like it could easily be folded into doMalloc
709	static inline void * malloc2( size_t size ) { // necessary for malloc statistics
710	assert( heapManager.heapBegin != 0 );
711	void * area = doMalloc( size );
712	if ( unlikely( area == 0 ) ) errno = ENOMEM; // POSIX
713	return area;
714	} // malloc2
715
716
717	static inline void * memalign2( size_t alignment, size_t size ) { // necessary for malloc statistics
718	#ifdef __CFA_DEBUG__
719	checkAlign( alignment ); // check alignment
720	#endif // __CFA_DEBUG__
721
722	// if alignment <= default alignment, do normal malloc as two headers are unnecessary
723	if ( unlikely( alignment <= libAlign() ) ) return malloc2( size );
724
725	// Allocate enough storage to guarantee an address on the alignment boundary, and sufficient space before it for
726	// administrative storage. NOTE, WHILE THERE ARE 2 HEADERS, THE FIRST ONE IS IMPLICITLY CREATED BY DOMALLOC.
727	// .-------------v-----------------v----------------v----------,
728	// \| Real Header \| ... padding ... \| Fake Header \| data ... \|
729	// `-------------^-----------------^-+--------------^----------'
730	// \|<--------------------------------' offset/align \|<-- alignment boundary
731
732	// subtract libAlign() because it is already the minimum alignment
733	// add sizeof(Storage) for fake header
734	// #comment TD : this is the only place that calls doMalloc without calling malloc2, why ?
735	char * area = (char *)doMalloc( size + alignment - libAlign() + sizeof(HeapManager.Storage) );
736	if ( unlikely( area == 0 ) ) return area;
737
738	// address in the block of the "next" alignment address
739	char * user = (char *)libCeiling( (uintptr_t)(area + sizeof(HeapManager.Storage)), alignment );
740
741	// address of header from malloc
742	HeapManager.Storage.Header * realHeader = headerAddr( area );
743	// address of fake header * before* the alignment location
744	HeapManager.Storage.Header * fakeHeader = headerAddr( user );
745	// SKULLDUGGERY: insert the offset to the start of the actual storage block and remember alignment
746	fakeHeader->kind.fake.offset = (char )fakeHeader - (char )realHeader;
747	// SKULLDUGGERY: odd alignment imples fake header
748	fakeHeader->kind.fake.alignment = alignment \| 1;
749
750	return user;
751	} // memalign2
752
753
754	extern "C" {
755	// The malloc() function allocates size bytes and returns a pointer to the
756	// allocated memory. The memory is not initialized. If size is 0, then malloc()
757	// returns either NULL, or a unique pointer value that can later be successfully
758	// passed to free().
759	void * malloc( size_t size ) {
760	#ifdef __STATISTICS__
761	__atomic_add_fetch( &malloc_calls, 1, __ATOMIC_SEQ_CST );
762	__atomic_add_fetch( &malloc_storage, size, __ATOMIC_SEQ_CST );
763	#endif // __STATISTICS__
764
765	return malloc2( size );
766	} // malloc
767
768	// The calloc() function allocates memory for an array of nmemb elements of
769	// size bytes each and returns a pointer to the allocated memory. The memory
770	// is set to zero. If nmemb or size is 0, then calloc() returns either NULL,
771	// or a unique pointer value that can later be successfully passed to free().
772	void * calloc( size_t noOfElems, size_t elemSize ) {
773	size_t size = noOfElems * elemSize;
774	#ifdef __STATISTICS__
775	__atomic_add_fetch( &calloc_calls, 1, __ATOMIC_SEQ_CST );
776	__atomic_add_fetch( &calloc_storage, size, __ATOMIC_SEQ_CST );
777	#endif // __STATISTICS__
778
779	char * area = (char *)malloc2( size );
780	if ( unlikely( area == 0 ) ) return 0;
781
782	HeapManager.Storage.Header * header;
783	HeapManager.FreeHeader * freeElem;
784	size_t asize, alignment;
785	bool mapped __attribute__(( unused )) = headers( "calloc", area, header, freeElem, asize, alignment );
786	#ifndef __CFA_DEBUG__
787	// Mapped storage is zero filled, but in debug mode mapped memory is scrubbed in doMalloc, so it has to be reset to zero.
788	if ( ! mapped )
789	#endif // __CFA_DEBUG__
790	memset( area, '\0', asize - sizeof(HeapManager.Storage) ); // set to zeros
791
792	header->kind.real.blockSize \|= 2; // mark as zero filled
793	return area;
794	} // calloc
795
796	// #comment TD : Document this function
797	void * cmemalign( size_t alignment, size_t noOfElems, size_t elemSize ) {
798	size_t size = noOfElems * elemSize;
799	#ifdef __STATISTICS__
800	__atomic_add_fetch( &cmemalign_calls, 1, __ATOMIC_SEQ_CST );
801	__atomic_add_fetch( &cmemalign_storage, size, __ATOMIC_SEQ_CST );
802	#endif // __STATISTICS__
803
804	char * area = (char *)memalign2( alignment, size );
805	if ( unlikely( area == 0 ) ) return 0;
806	HeapManager.Storage.Header * header;
807	HeapManager.FreeHeader * freeElem;
808	size_t asize;
809	bool mapped __attribute__(( unused )) = headers( "cmemalign", area, header, freeElem, asize, alignment );
810	#ifndef __CFA_DEBUG__
811	// Mapped storage is zero filled, but in debug mode mapped memory is scrubbed in doMalloc, so it has to be reset to zero.
812	if ( ! mapped )
813	#endif // __CFA_DEBUG__
814	memset( area, '\0', asize - ( (char )area - (char )header ) ); // set to zeros
815	header->kind.real.blockSize \|= 2; // mark as zero filled
816
817	return area;
818	} // cmemalign
819
820	// The realloc() function changes the size of the memory block pointed to by
821	// ptr to size bytes. The contents will be unchanged in the range from the
822	// start of the region up to the minimum of the old and new sizes. If the new
823	// size is larger than the old size, the added memory will not be initialized.
824	// If ptr is NULL, then the call is equivalent to malloc(size), for all values
825	// of size; if size is equal to zero, and ptr is not NULL, then the call is
826	// equivalent to free(ptr). Unless ptr is NULL, it must have been returned by
827	// an earlier call to malloc(), calloc() or realloc(). If the area pointed to
828	// was moved, a free(ptr) is done.
829	void * realloc( void * addr, size_t size ) {
830	#ifdef __STATISTICS__
831	__atomic_add_fetch( &realloc_calls, 1, __ATOMIC_SEQ_CST );
832	#endif // __STATISTICS__
833
834	if ( unlikely( addr == 0 ) ) return malloc2( size ); // special cases
835	if ( unlikely( size == 0 ) ) { free( addr ); return 0; }
836
837	HeapManager.Storage.Header * header;
838	HeapManager.FreeHeader * freeElem;
839	size_t asize, alignment = 0;
840	headers( "realloc", addr, header, freeElem, asize, alignment );
841
842	size_t usize = asize - ( (char )addr - (char )header ); // compute the amount of user storage in the block
843	if ( usize >= size ) { // already sufficient storage
844	// This case does not result in a new profiler entry because the previous one still exists and it must match with
845	// the free for this memory. Hence, this realloc does not appear in the profiler output.
846	return addr;
847	} // if
848
849	#ifdef __STATISTICS__
850	__atomic_add_fetch( &realloc_storage, size, __ATOMIC_SEQ_CST );
851	#endif // __STATISTICS__
852
853	void * area;
854	if ( unlikely( alignment != 0 ) ) { // previous request memalign?
855	area = memalign( alignment, size ); // create new area
856	} else {
857	area = malloc2( size ); // create new area
858	} // if
859	if ( unlikely( area == 0 ) ) return 0;
860	if ( unlikely( header->kind.real.blockSize & 2 ) ) { // previous request zero fill (calloc/cmemalign) ?
861	assert( (header->kind.real.blockSize & 1) == 0 );
862	bool mapped __attribute__(( unused )) = headers( "realloc", area, header, freeElem, asize, alignment );
863	#ifndef __CFA_DEBUG__
864	// Mapped storage is zero filled, but in debug mode mapped memory is scrubbed in doMalloc, so it has to be reset to zero.
865	if ( ! mapped )
866	#endif // __CFA_DEBUG__
867	memset( (char )area + usize, '\0', asize - ( (char )area - (char *)header ) - usize ); // zero-fill back part
868	header->kind.real.blockSize \|= 2; // mark new request as zero fill
869	} // if
870	memcpy( area, addr, usize ); // copy bytes
871	free( addr );
872	return area;
873	} // realloc
874
875
876	// The obsolete function memalign() allocates size bytes and returns
877	// a pointer to the allocated memory. The memory address will be a
878	// multiple of alignment, which must be a power of two.
879	void * memalign( size_t alignment, size_t size ) __attribute__ ((deprecated));
880	void * memalign( size_t alignment, size_t size ) {
881	#ifdef __STATISTICS__
882	__atomic_add_fetch( &memalign_calls, 1, __ATOMIC_SEQ_CST );
883	__atomic_add_fetch( &memalign_storage, size, __ATOMIC_SEQ_CST );
884	#endif // __STATISTICS__
885
886	void * area = memalign2( alignment, size );
887
888	return area;
889	} // memalign
890
891	// The function aligned_alloc() is the same as memalign(), except for
892	// the added restriction that size should be a multiple of alignment.
893	void * aligned_alloc( size_t alignment, size_t size ) {
894	return memalign( alignment, size );
895	} // aligned_alloc
896
897
898	// The function posix_memalign() allocates size bytes and places the address
899	// of the allocated memory in *memptr. The address of the allocated memory
900	// will be a multiple of alignment, which must be a power of two and a multiple
901	// of sizeof(void *). If size is 0, then posix_memalign() returns either NULL,
902	// or a unique pointer value that can later be successfully passed to free(3).
903	int posix_memalign( void ** memptr, size_t alignment, size_t size ) {
904	if ( alignment < sizeof(void *) \|\| ! libPow2( alignment ) ) return EINVAL; // check alignment
905	* memptr = memalign( alignment, size );
906	if ( unlikely( * memptr == 0 ) ) return ENOMEM;
907	return 0;
908	} // posix_memalign
909
910	// The obsolete function valloc() allocates size bytes and returns a pointer
911	// to the allocated memory. The memory address will be a multiple of the page size.
912	// It is equivalent to memalign(sysconf(_SC_PAGESIZE),size).
913	void * valloc( size_t size ) __attribute__ ((deprecated));
914	void * valloc( size_t size ) {
915	return memalign( pageSize, size );
916	} // valloc
917
918
919	// The free() function frees the memory space pointed to by ptr, which must
920	// have been returned by a previous call to malloc(), calloc() or realloc().
921	// Otherwise, or if free(ptr) has already been called before, undefined
922	// behavior occurs. If ptr is NULL, no operation is performed.
923	void free( void * addr ) {
924	#ifdef __STATISTICS__
925	__atomic_add_fetch( &free_calls, 1, __ATOMIC_SEQ_CST );
926	#endif // __STATISTICS__
927
928	// #comment TD : To decrease nesting I would but the special case in the
929	// else instead, plus it reads more naturally to have the
930	// short / normal case instead
931	if ( unlikely( addr == 0 ) ) { // special case
932	#ifdef __CFA_DEBUG__
933	if ( traceHeap() ) {
934	#define nullmsg "Free( 0x0 ) size:0\n"
935	// Do not debug print free( 0 ), as it can cause recursive entry from sprintf.
936	__cfaabi_dbg_bits_write( nullmsg, sizeof(nullmsg) - 1 );
937	} // if
938	#endif // __CFA_DEBUG__
939	return;
940	} // exit
941
942	doFree( addr );
943	} // free
944
945	// The mallopt() function adjusts parameters that control the behavior of the
946	// memory-allocation functions (see malloc(3)). The param argument specifies
947	// the parameter to be modified, and value specifies the new value for that
948	// parameter.
949	int mallopt( int option, int value ) {
950	choose( option ) {
951	case M_TOP_PAD:
952	if ( setHeapExpand( value ) ) fallthru default;
953	case M_MMAP_THRESHOLD:
954	if ( setMmapStart( value ) ) fallthru default;
955	default:
956	// #comment TD : 1 for unsopported feels wrong
957	return 1; // success, or unsupported
958	} // switch
959	return 0; // error
960	} // mallopt
961
962	// The malloc_trim() function attempts to release free memory at the top
963	// of the heap (by calling sbrk(2) with a suitable argument).
964	int malloc_trim( size_t ) {
965	return 0; // => impossible to release memory
966	} // malloc_trim
967
968	// The malloc_usable_size() function returns the number of usable bytes in the
969	// block pointed to by ptr, a pointer to a block of memory allocated by
970	// malloc(3) or a related function.
971	size_t malloc_usable_size( void * addr ) {
972	if ( unlikely( addr == 0 ) ) return 0; // null allocation has 0 size
973
974	HeapManager.Storage.Header * header;
975	HeapManager.FreeHeader * freeElem;
976	size_t size, alignment;
977
978	headers( "malloc_usable_size", addr, header, freeElem, size, alignment );
979	size_t usize = size - ( (char )addr - (char )header ); // compute the amount of user storage in the block
980	return usize;
981	} // malloc_usable_size
982
983
984	// #comment TD : Document this function
985	size_t malloc_alignment( void * addr ) {
986	if ( unlikely( addr == 0 ) ) return libAlign(); // minimum alignment
987	HeapManager.Storage.Header * header = (HeapManager.Storage.Header )( (char )addr - sizeof(HeapManager.Storage) );
988	if ( (header->kind.fake.alignment & 1) == 1 ) { // fake header ?
989	return header->kind.fake.alignment & -2; // remove flag from value
990	} else {
991	return libAlign (); // minimum alignment
992	} // if
993	} // malloc_alignment
994
995
996	// #comment TD : Document this function
997	bool malloc_zero_fill( void * addr ) {
998	if ( unlikely( addr == 0 ) ) return false; // null allocation is not zero fill
999
1000	HeapManager.Storage.Header * header = (HeapManager.Storage.Header )( (char )addr - sizeof(HeapManager.Storage) );
1001	if ( (header->kind.fake.alignment & 1) == 1 ) { // fake header ?
1002	header = (HeapManager.Storage.Header )((char )header - header->kind.fake.offset);
1003	} // if
1004	return (header->kind.real.blockSize & 2) != 0; // zero filled (calloc/cmemalign) ?
1005	} // malloc_zero_fill
1006
1007
1008	// #comment TD : Document this function
1009	void malloc_stats( void ) {
1010	#ifdef __STATISTICS__
1011	printStats();
1012	if ( checkFree() ) checkFree( heapManager );
1013	#endif // __STATISTICS__
1014	} // malloc_stats
1015
1016	// #comment TD : Document this function
1017	int malloc_stats_fd( int fd ) {
1018	#ifdef __STATISTICS__
1019	int temp = statfd;
1020	statfd = fd;
1021	return temp;
1022	#else
1023	return -1;
1024	#endif // __STATISTICS__
1025	} // malloc_stats_fd
1026
1027
1028	// #comment TD : Document this function
1029	int malloc_info( int options, FILE * stream ) {
1030	return printStatsXML( stream );
1031	} // malloc_info
1032
1033
1034	// #comment TD : What are these two functions for?
1035	void * malloc_get_state( void ) {
1036	return 0;
1037	} // malloc_get_state
1038
1039	int malloc_set_state( void * ptr ) {
1040	return 0;
1041	} // malloc_set_state
1042	} // extern "C"
1043
1044
1045	// Local Variables: //
1046	// tab-width: 4 //
1047	// compile-command: "cfa -nodebug -O2 heap.c" //
1048	// End: //

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