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Diffstat (limited to '')
| -rw-r--r-- | emmalloc/emmalloc.c | 1535 |
1 files changed, 1535 insertions, 0 deletions
diff --git a/emmalloc/emmalloc.c b/emmalloc/emmalloc.c new file mode 100644 index 0000000..c98e42e --- /dev/null +++ b/emmalloc/emmalloc.c @@ -0,0 +1,1535 @@ +/* + * Copyright 2018 The Emscripten Authors. All rights reserved. + * Emscripten is available under two separate licenses, the MIT license and the + * University of Illinois/NCSA Open Source License. Both these licenses can be + * found in the LICENSE file. + * + * Simple minimalistic but efficient sbrk()-based malloc/free that works in + * singlethreaded and multithreaded builds. + * + * Assumptions: + * + * - sbrk() is used to claim new memory (sbrk handles geometric/linear + * - overallocation growth) + * - sbrk() can be used by other code outside emmalloc. + * - sbrk() is very fast in most cases (internal wasm call). + * - sbrk() returns pointers with an alignment of alignof(max_align_t) + * + * Invariants: + * + * - Per-allocation header overhead is 8 bytes, smallest allocated payload + * amount is 8 bytes, and a multiple of 4 bytes. + * - Acquired memory blocks are subdivided into disjoint regions that lie + * next to each other. + * - A region is either in used or free. + * Used regions may be adjacent, and a used and unused region + * may be adjacent, but not two unused ones - they would be + * merged. + * - Memory allocation takes constant time, unless the alloc needs to sbrk() + * or memory is very close to being exhausted. + * + * Debugging: + * + * - If not NDEBUG, runtime assert()s are in use. + * - If EMMALLOC_MEMVALIDATE is defined, a large amount of extra checks are done. + * - If EMMALLOC_VERBOSE is defined, a lot of operations are logged + * out, in addition to EMMALLOC_MEMVALIDATE. + * - Debugging and logging directly uses console.log via uses EM_ASM, not + * printf etc., to minimize any risk of debugging or logging depending on + * malloc. + */ + +#include <stdalign.h> +#include <stdbool.h> +#include <stddef.h> +#include <stdint.h> +#include <unistd.h> +#include <memory.h> +#include <assert.h> +#include <malloc.h> +#include <limits.h> +#include <stdlib.h> + +#ifdef __EMSCRIPTEN_TRACING__ +#include <emscripten/trace.h> +#endif + +// Defind by the linker to have the address of the start of the heap. +extern unsigned char __heap_base; + +// Behavior of right shifting a signed integer is compiler implementation defined. +static_assert((((int32_t)0x80000000U) >> 31) == -1, "This malloc implementation requires that right-shifting a signed integer produces a sign-extending (arithmetic) shift!"); + +// Configuration: specifies the minimum alignment that malloc()ed memory outputs. Allocation requests with smaller alignment +// than this will yield an allocation with this much alignment. +#define MALLOC_ALIGNMENT alignof(max_align_t) +static_assert(alignof(max_align_t) == 16, "max_align_t must be correct"); + +#define EMMALLOC_EXPORT __attribute__((weak)) + +#define MIN(x, y) ((x) < (y) ? (x) : (y)) +#define MAX(x, y) ((x) > (y) ? (x) : (y)) + +#define NUM_FREE_BUCKETS 64 +#define BUCKET_BITMASK_T uint64_t + +// Dynamic memory is subdivided into regions, in the format + +// <size:uint32_t> ..... <size:uint32_t> | <size:uint32_t> ..... <size:uint32_t> | <size:uint32_t> ..... <size:uint32_t> | ..... + +// That is, at the bottom and top end of each memory region, the size of that region is stored. That allows traversing the +// memory regions backwards and forwards. Because each allocation must be at least a multiple of 4 bytes, the lowest two bits of +// each size field is unused. Free regions are distinguished by used regions by having the FREE_REGION_FLAG bit present +// in the size field. I.e. for free regions, the size field is odd, and for used regions, the size field reads even. +#define FREE_REGION_FLAG 0x1u + +// Attempts to malloc() more than this many bytes would cause an overflow when calculating the size of a region, +// therefore allocations larger than this are short-circuited immediately on entry. +#define MAX_ALLOC_SIZE 0xFFFFFFC7u + +// A free region has the following structure: +// <size:size_t> <prevptr> <nextptr> ... <size:size_t> + +typedef struct Region +{ + size_t size; + // Use a circular doubly linked list to represent free region data. + struct Region *prev, *next; + // ... N bytes of free data + size_t _at_the_end_of_this_struct_size; // do not dereference, this is present for convenient struct sizeof() computation only +} Region; + +// Each memory block starts with a RootRegion at the beginning. +// The RootRegion specifies the size of the region block, and forms a linked +// list of all RootRegions in the program, starting with `listOfAllRegions` +// below. +typedef struct RootRegion +{ + uint32_t size; + struct RootRegion *next; + uint8_t* endPtr; +} RootRegion; + +#if defined(__EMSCRIPTEN_PTHREADS__) +// In multithreaded builds, use a simple global spinlock strategy to acquire/release access to the memory allocator. +static volatile uint8_t multithreadingLock = 0; +#define MALLOC_ACQUIRE() while(__sync_lock_test_and_set(&multithreadingLock, 1)) { while(multithreadingLock) { /*nop*/ } } +#define MALLOC_RELEASE() __sync_lock_release(&multithreadingLock) +// Test code to ensure we have tight malloc acquire/release guards in place. +#define ASSERT_MALLOC_IS_ACQUIRED() assert(multithreadingLock == 1) +#else +// In singlethreaded builds, no need for locking. +#define MALLOC_ACQUIRE() ((void)0) +#define MALLOC_RELEASE() ((void)0) +#define ASSERT_MALLOC_IS_ACQUIRED() ((void)0) +#endif + +#define IS_POWER_OF_2(val) (((val) & ((val)-1)) == 0) +#define ALIGN_UP(ptr, alignment) ((uint8_t*)((((uintptr_t)(ptr)) + ((alignment)-1)) & ~((alignment)-1))) +#define HAS_ALIGNMENT(ptr, alignment) ((((uintptr_t)(ptr)) & ((alignment)-1)) == 0) + +static_assert(IS_POWER_OF_2(MALLOC_ALIGNMENT), "MALLOC_ALIGNMENT must be a power of two value!"); +static_assert(MALLOC_ALIGNMENT >= 4, "Smallest possible MALLOC_ALIGNMENT if 4!"); + +// A region that contains as payload a single forward linked list of pointers to +// root regions of each disjoint region blocks. +static RootRegion *listOfAllRegions = NULL; + +// For each of the buckets, maintain a linked list head node. The head node for each +// free region is a sentinel node that does not actually represent any free space, but +// the sentinel is used to avoid awkward testing against (if node == freeRegionHeadNode) +// when adding and removing elements from the linked list, i.e. we are guaranteed that +// the sentinel node is always fixed and there, and the actual free region list elements +// start at freeRegionBuckets[i].next each. +static Region freeRegionBuckets[NUM_FREE_BUCKETS] = { + { .prev = &freeRegionBuckets[0], .next = &freeRegionBuckets[0] }, + { .prev = &freeRegionBuckets[1], .next = &freeRegionBuckets[1] }, + { .prev = &freeRegionBuckets[2], .next = &freeRegionBuckets[2] }, + { .prev = &freeRegionBuckets[3], .next = &freeRegionBuckets[3] }, + { .prev = &freeRegionBuckets[4], .next = &freeRegionBuckets[4] }, + { .prev = &freeRegionBuckets[5], .next = &freeRegionBuckets[5] }, + { .prev = &freeRegionBuckets[6], .next = &freeRegionBuckets[6] }, + { .prev = &freeRegionBuckets[7], .next = &freeRegionBuckets[7] }, + { .prev = &freeRegionBuckets[8], .next = &freeRegionBuckets[8] }, + { .prev = &freeRegionBuckets[9], .next = &freeRegionBuckets[9] }, + { .prev = &freeRegionBuckets[10], .next = &freeRegionBuckets[10] }, + { .prev = &freeRegionBuckets[11], .next = &freeRegionBuckets[11] }, + { .prev = &freeRegionBuckets[12], .next = &freeRegionBuckets[12] }, + { .prev = &freeRegionBuckets[13], .next = &freeRegionBuckets[13] }, + { .prev = &freeRegionBuckets[14], .next = &freeRegionBuckets[14] }, + { .prev = &freeRegionBuckets[15], .next = &freeRegionBuckets[15] }, + { .prev = &freeRegionBuckets[16], .next = &freeRegionBuckets[16] }, + { .prev = &freeRegionBuckets[17], .next = &freeRegionBuckets[17] }, + { .prev = &freeRegionBuckets[18], .next = &freeRegionBuckets[18] }, + { .prev = &freeRegionBuckets[19], .next = &freeRegionBuckets[19] }, + { .prev = &freeRegionBuckets[20], .next = &freeRegionBuckets[20] }, + { .prev = &freeRegionBuckets[21], .next = &freeRegionBuckets[21] }, + { .prev = &freeRegionBuckets[22], .next = &freeRegionBuckets[22] }, + { .prev = &freeRegionBuckets[23], .next = &freeRegionBuckets[23] }, + { .prev = &freeRegionBuckets[24], .next = &freeRegionBuckets[24] }, + { .prev = &freeRegionBuckets[25], .next = &freeRegionBuckets[25] }, + { .prev = &freeRegionBuckets[26], .next = &freeRegionBuckets[26] }, + { .prev = &freeRegionBuckets[27], .next = &freeRegionBuckets[27] }, + { .prev = &freeRegionBuckets[28], .next = &freeRegionBuckets[28] }, + { .prev = &freeRegionBuckets[29], .next = &freeRegionBuckets[29] }, + { .prev = &freeRegionBuckets[30], .next = &freeRegionBuckets[30] }, + { .prev = &freeRegionBuckets[31], .next = &freeRegionBuckets[31] }, + { .prev = &freeRegionBuckets[32], .next = &freeRegionBuckets[32] }, + { .prev = &freeRegionBuckets[33], .next = &freeRegionBuckets[33] }, + { .prev = &freeRegionBuckets[34], .next = &freeRegionBuckets[34] }, + { .prev = &freeRegionBuckets[35], .next = &freeRegionBuckets[35] }, + { .prev = &freeRegionBuckets[36], .next = &freeRegionBuckets[36] }, + { .prev = &freeRegionBuckets[37], .next = &freeRegionBuckets[37] }, + { .prev = &freeRegionBuckets[38], .next = &freeRegionBuckets[38] }, + { .prev = &freeRegionBuckets[39], .next = &freeRegionBuckets[39] }, + { .prev = &freeRegionBuckets[40], .next = &freeRegionBuckets[40] }, + { .prev = &freeRegionBuckets[41], .next = &freeRegionBuckets[41] }, + { .prev = &freeRegionBuckets[42], .next = &freeRegionBuckets[42] }, + { .prev = &freeRegionBuckets[43], .next = &freeRegionBuckets[43] }, + { .prev = &freeRegionBuckets[44], .next = &freeRegionBuckets[44] }, + { .prev = &freeRegionBuckets[45], .next = &freeRegionBuckets[45] }, + { .prev = &freeRegionBuckets[46], .next = &freeRegionBuckets[46] }, + { .prev = &freeRegionBuckets[47], .next = &freeRegionBuckets[47] }, + { .prev = &freeRegionBuckets[48], .next = &freeRegionBuckets[48] }, + { .prev = &freeRegionBuckets[49], .next = &freeRegionBuckets[49] }, + { .prev = &freeRegionBuckets[50], .next = &freeRegionBuckets[50] }, + { .prev = &freeRegionBuckets[51], .next = &freeRegionBuckets[51] }, + { .prev = &freeRegionBuckets[52], .next = &freeRegionBuckets[52] }, + { .prev = &freeRegionBuckets[53], .next = &freeRegionBuckets[53] }, + { .prev = &freeRegionBuckets[54], .next = &freeRegionBuckets[54] }, + { .prev = &freeRegionBuckets[55], .next = &freeRegionBuckets[55] }, + { .prev = &freeRegionBuckets[56], .next = &freeRegionBuckets[56] }, + { .prev = &freeRegionBuckets[57], .next = &freeRegionBuckets[57] }, + { .prev = &freeRegionBuckets[58], .next = &freeRegionBuckets[58] }, + { .prev = &freeRegionBuckets[59], .next = &freeRegionBuckets[59] }, + { .prev = &freeRegionBuckets[60], .next = &freeRegionBuckets[60] }, + { .prev = &freeRegionBuckets[61], .next = &freeRegionBuckets[61] }, + { .prev = &freeRegionBuckets[62], .next = &freeRegionBuckets[62] }, + { .prev = &freeRegionBuckets[63], .next = &freeRegionBuckets[63] }, +}; + +// A bitmask that tracks the population status for each of the 64 distinct memory regions: +// a zero at bit position i means that the free list bucket i is empty. This bitmask is +// used to avoid redundant scanning of the 64 different free region buckets: instead by +// looking at the bitmask we can find in constant time an index to a free region bucket +// that contains free memory of desired size. +static BUCKET_BITMASK_T freeRegionBucketsUsed = 0; + +// Amount of bytes taken up by allocation header data +#define REGION_HEADER_SIZE (2*sizeof(size_t)) + +// Smallest allocation size that is possible is 2*pointer size, since payload of each region must at least contain space +// to store the free region linked list prev and next pointers. An allocation size smaller than this will be rounded up +// to this size. +#define SMALLEST_ALLOCATION_SIZE (2*sizeof(void*)) + +/* Subdivide regions of free space into distinct circular doubly linked lists, where each linked list +represents a range of free space blocks. The following function compute_free_list_bucket() converts +an allocation size to the bucket index that should be looked at. The buckets are grouped as follows: + + Bucket 0: [8, 15], range size=8 + Bucket 1: [16, 23], range size=8 + Bucket 2: [24, 31], range size=8 + Bucket 3: [32, 39], range size=8 + Bucket 4: [40, 47], range size=8 + Bucket 5: [48, 55], range size=8 + Bucket 6: [56, 63], range size=8 + Bucket 7: [64, 71], range size=8 + Bucket 8: [72, 79], range size=8 + Bucket 9: [80, 87], range size=8 + Bucket 10: [88, 95], range size=8 + Bucket 11: [96, 103], range size=8 + Bucket 12: [104, 111], range size=8 + Bucket 13: [112, 119], range size=8 + Bucket 14: [120, 159], range size=40 + Bucket 15: [160, 191], range size=32 + Bucket 16: [192, 223], range size=32 + Bucket 17: [224, 255], range size=32 + Bucket 18: [256, 319], range size=64 + Bucket 19: [320, 383], range size=64 + Bucket 20: [384, 447], range size=64 + Bucket 21: [448, 511], range size=64 + Bucket 22: [512, 639], range size=128 + Bucket 23: [640, 767], range size=128 + Bucket 24: [768, 895], range size=128 + Bucket 25: [896, 1023], range size=128 + Bucket 26: [1024, 1279], range size=256 + Bucket 27: [1280, 1535], range size=256 + Bucket 28: [1536, 1791], range size=256 + Bucket 29: [1792, 2047], range size=256 + Bucket 30: [2048, 2559], range size=512 + Bucket 31: [2560, 3071], range size=512 + Bucket 32: [3072, 3583], range size=512 + Bucket 33: [3584, 6143], range size=2560 + Bucket 34: [6144, 8191], range size=2048 + Bucket 35: [8192, 12287], range size=4096 + Bucket 36: [12288, 16383], range size=4096 + Bucket 37: [16384, 24575], range size=8192 + Bucket 38: [24576, 32767], range size=8192 + Bucket 39: [32768, 49151], range size=16384 + Bucket 40: [49152, 65535], range size=16384 + Bucket 41: [65536, 98303], range size=32768 + Bucket 42: [98304, 131071], range size=32768 + Bucket 43: [131072, 196607], range size=65536 + Bucket 44: [196608, 262143], range size=65536 + Bucket 45: [262144, 393215], range size=131072 + Bucket 46: [393216, 524287], range size=131072 + Bucket 47: [524288, 786431], range size=262144 + Bucket 48: [786432, 1048575], range size=262144 + Bucket 49: [1048576, 1572863], range size=524288 + Bucket 50: [1572864, 2097151], range size=524288 + Bucket 51: [2097152, 3145727], range size=1048576 + Bucket 52: [3145728, 4194303], range size=1048576 + Bucket 53: [4194304, 6291455], range size=2097152 + Bucket 54: [6291456, 8388607], range size=2097152 + Bucket 55: [8388608, 12582911], range size=4194304 + Bucket 56: [12582912, 16777215], range size=4194304 + Bucket 57: [16777216, 25165823], range size=8388608 + Bucket 58: [25165824, 33554431], range size=8388608 + Bucket 59: [33554432, 50331647], range size=16777216 + Bucket 60: [50331648, 67108863], range size=16777216 + Bucket 61: [67108864, 100663295], range size=33554432 + Bucket 62: [100663296, 134217727], range size=33554432 + Bucket 63: 134217728 bytes and larger. */ +static_assert(NUM_FREE_BUCKETS == 64, "Following function is tailored specifically for NUM_FREE_BUCKETS == 64 case"); +static int compute_free_list_bucket(size_t allocSize) +{ + if (allocSize < 128) return (allocSize >> 3) - 1; + int clz = __builtin_clz(allocSize); + int bucketIndex = (clz > 19) ? 110 - (clz<<2) + ((allocSize >> (29-clz)) ^ 4) : MIN(71 - (clz<<1) + ((allocSize >> (30-clz)) ^ 2), NUM_FREE_BUCKETS-1); + assert(bucketIndex >= 0); + assert(bucketIndex < NUM_FREE_BUCKETS); + return bucketIndex; +} + +#define DECODE_CEILING_SIZE(size) ((size_t)((size) & ~FREE_REGION_FLAG)) + +static Region *prev_region(Region *region) +{ + size_t prevRegionSize = ((size_t*)region)[-1]; + prevRegionSize = DECODE_CEILING_SIZE(prevRegionSize); + return (Region*)((uint8_t*)region - prevRegionSize); +} + +static Region *next_region(Region *region) +{ + return (Region*)((uint8_t*)region + region->size); +} + +static size_t region_ceiling_size(Region *region) +{ + return ((size_t*)((uint8_t*)region + region->size))[-1]; +} + +static bool region_is_free(Region *r) +{ + return region_ceiling_size(r) & FREE_REGION_FLAG; +} + +static bool region_is_in_use(Region *r) +{ + return r->size == region_ceiling_size(r); +} + +static size_t size_of_region_from_ceiling(Region *r) +{ + size_t size = region_ceiling_size(r); + return DECODE_CEILING_SIZE(size); +} + +static bool debug_region_is_consistent(Region *r) +{ + assert(r); + size_t sizeAtBottom = r->size; + size_t sizeAtCeiling = size_of_region_from_ceiling(r); + return sizeAtBottom == sizeAtCeiling; +} + +static uint8_t *region_payload_start_ptr(Region *region) +{ + return (uint8_t*)region + sizeof(size_t); +} + +static uint8_t *region_payload_end_ptr(Region *region) +{ + return (uint8_t*)region + region->size - sizeof(size_t); +} + +static void create_used_region(void *ptr, size_t size) +{ + assert(ptr); + assert(HAS_ALIGNMENT(ptr, sizeof(size_t))); + assert(HAS_ALIGNMENT(size, sizeof(size_t))); + assert(size >= sizeof(Region)); + *(size_t*)ptr = size; + ((size_t*)ptr)[(size/sizeof(size_t))-1] = size; +} + +static void create_free_region(void *ptr, size_t size) +{ + assert(ptr); + assert(HAS_ALIGNMENT(ptr, sizeof(size_t))); + assert(HAS_ALIGNMENT(size, sizeof(size_t))); + assert(size >= sizeof(Region)); + Region *freeRegion = (Region*)ptr; + freeRegion->size = size; + ((size_t*)ptr)[(size/sizeof(size_t))-1] = size | FREE_REGION_FLAG; +} + +static void prepend_to_free_list(Region *region, Region *prependTo) +{ + assert(region); + assert(prependTo); + // N.b. the region we are prepending to is always the sentinel node, + // which represents a dummy node that is technically not a free node, so + // region_is_free(prependTo) does not hold. + assert(region_is_free((Region*)region)); + region->next = prependTo; + region->prev = prependTo->prev; + assert(region->prev); + prependTo->prev = region; + region->prev->next = region; +} + +static void unlink_from_free_list(Region *region) +{ + assert(region); + assert(region_is_free((Region*)region)); + assert(region->prev); + assert(region->next); + region->prev->next = region->next; + region->next->prev = region->prev; +} + +static void link_to_free_list(Region *freeRegion) +{ + assert(freeRegion); + assert(freeRegion->size >= sizeof(Region)); + int bucketIndex = compute_free_list_bucket(freeRegion->size-REGION_HEADER_SIZE); + Region *freeListHead = freeRegionBuckets + bucketIndex; + freeRegion->prev = freeListHead; + freeRegion->next = freeListHead->next; + assert(freeRegion->next); + freeListHead->next = freeRegion; + freeRegion->next->prev = freeRegion; + freeRegionBucketsUsed |= ((BUCKET_BITMASK_T)1) << bucketIndex; +} + +#if 0 +static void dump_memory_regions() +{ + ASSERT_MALLOC_IS_ACQUIRED(); + RootRegion *root = listOfAllRegions; + MAIN_THREAD_ASYNC_EM_ASM(console.log('All memory regions:')); + while(root) + { + Region *r = (Region*)root; + assert(debug_region_is_consistent(r)); + uint8_t *lastRegionEnd = root->endPtr; + MAIN_THREAD_ASYNC_EM_ASM(console.log('Region block 0x'+($0>>>0).toString(16)+' - 0x'+($1>>>0).toString(16)+ ' ('+($2>>>0)+' bytes):'), + r, lastRegionEnd, lastRegionEnd-(uint8_t*)r); + while((uint8_t*)r < lastRegionEnd) + { + MAIN_THREAD_ASYNC_EM_ASM(console.log('Region 0x'+($0>>>0).toString(16)+', size: '+($1>>>0)+' ('+($2?"used":"--FREE--")+')'), + r, r->size, region_ceiling_size(r) == r->size); + + assert(debug_region_is_consistent(r)); + size_t sizeFromCeiling = size_of_region_from_ceiling(r); + if (sizeFromCeiling != r->size) + MAIN_THREAD_ASYNC_EM_ASM(console.log('Corrupt region! Size marker at the end of the region does not match: '+($0>>>0)), sizeFromCeiling); + if (r->size == 0) + break; + r = next_region(r); + } + root = root->next; + MAIN_THREAD_ASYNC_EM_ASM(console.log("")); + } + MAIN_THREAD_ASYNC_EM_ASM(console.log('Free regions:')); + for(int i = 0; i < NUM_FREE_BUCKETS; ++i) + { + Region *prev = &freeRegionBuckets[i]; + Region *fr = freeRegionBuckets[i].next; + while(fr != &freeRegionBuckets[i]) + { + MAIN_THREAD_ASYNC_EM_ASM(console.log('In bucket '+$0+', free region 0x'+($1>>>0).toString(16)+', size: ' + ($2>>>0) + ' (size at ceiling: '+($3>>>0)+'), prev: 0x' + ($4>>>0).toString(16) + ', next: 0x' + ($5>>>0).toString(16)), + i, fr, fr->size, size_of_region_from_ceiling(fr), fr->prev, fr->next); + assert(debug_region_is_consistent(fr)); + assert(region_is_free(fr)); + assert(fr->prev == prev); + prev = fr; + assert(fr->next != fr); + assert(fr->prev != fr); + fr = fr->next; + } + } + MAIN_THREAD_ASYNC_EM_ASM(console.log('Free bucket index map: ' + ($0>>>0).toString(2) + ' ' + ($1>>>0).toString(2)), (uint32_t)(freeRegionBucketsUsed >> 32), (uint32_t)freeRegionBucketsUsed); + MAIN_THREAD_ASYNC_EM_ASM(console.log("")); +} + +void emmalloc_dump_memory_regions() +{ + MALLOC_ACQUIRE(); + dump_memory_regions(); + MALLOC_RELEASE(); +} + +static int validate_memory_regions() +{ + ASSERT_MALLOC_IS_ACQUIRED(); + RootRegion *root = listOfAllRegions; + while(root) + { + Region *r = (Region*)root; + if (!debug_region_is_consistent(r)) + { + MAIN_THREAD_ASYNC_EM_ASM(console.error('Used region 0x'+($0>>>0).toString(16)+', size: '+($1>>>0)+' ('+($2?"used":"--FREE--")+') is corrupt (size markers in the beginning and at the end of the region do not match!)'), + r, r->size, region_ceiling_size(r) == r->size); + return 1; + } + uint8_t *lastRegionEnd = root->endPtr; + while((uint8_t*)r < lastRegionEnd) + { + if (!debug_region_is_consistent(r)) + { + MAIN_THREAD_ASYNC_EM_ASM(console.error('Used region 0x'+($0>>>0).toString(16)+', size: '+($1>>>0)+' ('+($2?"used":"--FREE--")+') is corrupt (size markers in the beginning and at the end of the region do not match!)'), + r, r->size, region_ceiling_size(r) == r->size); + return 1; + } + if (r->size == 0) + break; + r = next_region(r); + } + root = root->next; + } + for(int i = 0; i < NUM_FREE_BUCKETS; ++i) + { + Region *prev = &freeRegionBuckets[i]; + Region *fr = freeRegionBuckets[i].next; + while(fr != &freeRegionBuckets[i]) + { + if (!debug_region_is_consistent(fr) || !region_is_free(fr) || fr->prev != prev || fr->next == fr || fr->prev == fr) + { + MAIN_THREAD_ASYNC_EM_ASM(console.log('In bucket '+$0+', free region 0x'+($1>>>0).toString(16)+', size: ' + ($2>>>0) + ' (size at ceiling: '+($3>>>0)+'), prev: 0x' + ($4>>>0).toString(16) + ', next: 0x' + ($5>>>0).toString(16) + ' is corrupt!'), + i, fr, fr->size, size_of_region_from_ceiling(fr), fr->prev, fr->next); + return 1; + } + prev = fr; + fr = fr->next; + } + } + return 0; +} + +int emmalloc_validate_memory_regions() +{ + MALLOC_ACQUIRE(); + int memoryError = validate_memory_regions(); + MALLOC_RELEASE(); + return memoryError; +} +#endif + +static bool claim_more_memory(size_t numBytes) +{ +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('claim_more_memory(numBytes='+($0>>>0)+ ')'), numBytes); +#endif + +#ifdef EMMALLOC_MEMVALIDATE + validate_memory_regions(); +#endif + + uint8_t *startPtr; + uint8_t *endPtr; + do { + // If this is the first time we're called, see if we can use + // the initial heap memory set up by wasm-ld. + if (!listOfAllRegions) { + unsigned char *heap_end = sbrk(0); + if (numBytes <= (size_t)(heap_end - &__heap_base)) { + startPtr = &__heap_base; + endPtr = heap_end; + break; + } + } + + // Round numBytes up to the nearest page size. + numBytes = (numBytes + (PAGE_SIZE-1)) & -PAGE_SIZE; + + // Claim memory via sbrk + startPtr = (uint8_t*)sbrk(numBytes); + if ((intptr_t)startPtr == -1) + { +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.error('claim_more_memory: sbrk failed!')); +#endif + return false; + } +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('claim_more_memory: claimed 0x' + ($0>>>0).toString(16) + ' - 0x' + ($1>>>0).toString(16) + ' (' + ($2>>>0) + ' bytes) via sbrk()'), startPtr, startPtr + numBytes, numBytes); +#endif + assert(HAS_ALIGNMENT(startPtr, alignof(size_t))); + endPtr = startPtr + numBytes; + } while (0); + + // Create a sentinel region at the end of the new heap block + Region *endSentinelRegion = (Region*)(endPtr - sizeof(Region)); + create_used_region(endSentinelRegion, sizeof(Region)); + + // If we are the sole user of sbrk(), it will feed us continuous/consecutive memory addresses - take advantage + // of that if so: instead of creating two disjoint memory regions blocks, expand the previous one to a larger size. + uint8_t *previousSbrkEndAddress = listOfAllRegions ? listOfAllRegions->endPtr : 0; + if (startPtr == previousSbrkEndAddress) + { + Region *prevEndSentinel = prev_region((Region*)startPtr); + assert(debug_region_is_consistent(prevEndSentinel)); + assert(region_is_in_use(prevEndSentinel)); + Region *prevRegion = prev_region(prevEndSentinel); + assert(debug_region_is_consistent(prevRegion)); + + listOfAllRegions->endPtr = endPtr; + + // Two scenarios, either the last region of the previous block was in use, in which case we need to create + // a new free region in the newly allocated space; or it was free, in which case we can extend that region + // to cover a larger size. + if (region_is_free(prevRegion)) + { + size_t newFreeRegionSize = (uint8_t*)endSentinelRegion - (uint8_t*)prevRegion; + unlink_from_free_list(prevRegion); + create_free_region(prevRegion, newFreeRegionSize); + link_to_free_list(prevRegion); + return true; + } + // else: last region of the previous block was in use. Since we are joining two consecutive sbrk() blocks, + // we can swallow the end sentinel of the previous block away. + startPtr -= sizeof(Region); + } + else + { + // Create a root region at the start of the heap block + create_used_region(startPtr, sizeof(Region)); + + // Dynamic heap start region: + RootRegion *newRegionBlock = (RootRegion*)startPtr; + newRegionBlock->next = listOfAllRegions; // Pointer to next region block head + newRegionBlock->endPtr = endPtr; // Pointer to the end address of this region block + listOfAllRegions = newRegionBlock; + startPtr += sizeof(Region); + } + + // Create a new memory region for the new claimed free space. + create_free_region(startPtr, (uint8_t*)endSentinelRegion - startPtr); + link_to_free_list((Region*)startPtr); + return true; +} + +#if 0 +// Initialize emmalloc during static initialization. +// See system/lib/README.md for static constructor ordering. +__attribute__((constructor(47))) +static void initialize_emmalloc_heap() +{ + // Initialize circular doubly linked lists representing free space + // Never useful to unroll this for loop, just takes up code size. +#pragma clang loop unroll(disable) + for(int i = 0; i < NUM_FREE_BUCKETS; ++i) + freeRegionBuckets[i].prev = freeRegionBuckets[i].next = &freeRegionBuckets[i]; + +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('initialize_emmalloc_heap()')); +#endif + + // Start with a tiny dynamic region. + claim_more_memory(3*sizeof(Region)); +} + +void emmalloc_blank_slate_from_orbit() +{ + MALLOC_ACQUIRE(); + listOfAllRegions = NULL; + freeRegionBucketsUsed = 0; + initialize_emmalloc_heap(); + MALLOC_RELEASE(); +} +#endif + +static void *attempt_allocate(Region *freeRegion, size_t alignment, size_t size) +{ + ASSERT_MALLOC_IS_ACQUIRED(); + assert(freeRegion); + // Look at the next potential free region to allocate into. + // First, we should check if the free region has enough of payload bytes contained + // in it to accommodate the new allocation. This check needs to take account the + // requested allocation alignment, so the payload memory area needs to be rounded + // upwards to the desired alignment. + uint8_t *payloadStartPtr = region_payload_start_ptr(freeRegion); + uint8_t *payloadStartPtrAligned = ALIGN_UP(payloadStartPtr, alignment); + uint8_t *payloadEndPtr = region_payload_end_ptr(freeRegion); + + // Do we have enough free space, taking into account alignment? + if (payloadStartPtrAligned + size > payloadEndPtr) + return NULL; + + // We have enough free space, so the memory allocation will be made into this region. Remove this free region + // from the list of free regions: whatever slop remains will be later added back to the free region pool. + unlink_from_free_list(freeRegion); + + // Before we proceed further, fix up the boundary of this region and the region that precedes this one, + // so that the boundary between the two regions happens at a right spot for the payload to be aligned. + if (payloadStartPtr != payloadStartPtrAligned) + { + Region *prevRegion = prev_region((Region*)freeRegion); + // We never have two free regions adjacent to each other, so the region before this free + // region should be in use. + assert(region_is_in_use(prevRegion)); + size_t regionBoundaryBumpAmount = payloadStartPtrAligned - payloadStartPtr; + size_t newThisRegionSize = freeRegion->size - regionBoundaryBumpAmount; + create_used_region(prevRegion, prevRegion->size + regionBoundaryBumpAmount); + freeRegion = (Region *)((uint8_t*)freeRegion + regionBoundaryBumpAmount); + freeRegion->size = newThisRegionSize; + } + // Next, we need to decide whether this region is so large that it should be split into two regions, + // one representing the newly used memory area, and at the high end a remaining leftover free area. + // This splitting to two is done always if there is enough space for the high end to fit a region. + // Carve 'size' bytes of payload off this region. So, + // [sz prev next sz] + // becomes + // [sz payload sz] [sz prev next sz] + if (sizeof(Region) + REGION_HEADER_SIZE + size <= freeRegion->size) + { + // There is enough space to keep a free region at the end of the carved out block + // -> construct the new block + Region *newFreeRegion = (Region *)((uint8_t*)freeRegion + REGION_HEADER_SIZE + size); + create_free_region(newFreeRegion, freeRegion->size - size - REGION_HEADER_SIZE); + link_to_free_list(newFreeRegion); + + // Recreate the resized Region under its new size. + create_used_region(freeRegion, size + REGION_HEADER_SIZE); + } + else + { + // There is not enough space to split the free memory region into used+free parts, so consume the whole + // region as used memory, not leaving a free memory region behind. + // Initialize the free region as used by resetting the ceiling size to the same value as the size at bottom. + ((size_t*)((uint8_t*)freeRegion + freeRegion->size))[-1] = freeRegion->size; + } + +#ifdef __EMSCRIPTEN_TRACING__ + emscripten_trace_record_allocation(freeRegion, freeRegion->size); +#endif + +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('attempt_allocate - succeeded allocating memory, region ptr=0x' + ($0>>>0).toString(16) + ', align=' + $1 + ', payload size=' + ($2>>>0) + ' bytes)'), freeRegion, alignment, size); +#endif + + return (uint8_t*)freeRegion + sizeof(size_t); +} + +static size_t validate_alloc_alignment(size_t alignment) +{ + // Cannot perform allocations that are less than 4 byte aligned, because the Region + // control structures need to be aligned. Also round up to minimum outputted alignment. + alignment = MAX(alignment, MALLOC_ALIGNMENT); + // Arbitrary upper limit on alignment - very likely a programming bug if alignment is higher than this. + assert(alignment <= 1024*1024); + return alignment; +} + +static size_t validate_alloc_size(size_t size) +{ + assert(size + REGION_HEADER_SIZE > size); + + // Allocation sizes must be a multiple of pointer sizes, and at least 2*sizeof(pointer). + size_t validatedSize = size > SMALLEST_ALLOCATION_SIZE ? (size_t)ALIGN_UP(size, sizeof(Region*)) : SMALLEST_ALLOCATION_SIZE; + assert(validatedSize >= size); // 32-bit wraparound should not occur, too large sizes should be stopped before + + return validatedSize; +} + +static void *allocate_memory(size_t alignment, size_t size) +{ + ASSERT_MALLOC_IS_ACQUIRED(); + +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('allocate_memory(align=' + $0 + ', size=' + ($1>>>0) + ' bytes)'), alignment, size); +#endif + +#ifdef EMMALLOC_MEMVALIDATE + validate_memory_regions(); +#endif + + if (!IS_POWER_OF_2(alignment)) + { +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('Allocation failed: alignment not power of 2!')); +#endif + return 0; + } + + if (size > MAX_ALLOC_SIZE) + { +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('Allocation failed: attempted allocation size is too large: ' + ($0 >>> 0) + 'bytes! (negative integer wraparound?)'), size); +#endif + return 0; + } + + alignment = validate_alloc_alignment(alignment); + size = validate_alloc_size(size); + + // Attempt to allocate memory starting from smallest bucket that can contain the required amount of memory. + // Under normal alignment conditions this should always be the first or second bucket we look at, but if + // performing an allocation with complex alignment, we may need to look at multiple buckets. + int bucketIndex = compute_free_list_bucket(size); + BUCKET_BITMASK_T bucketMask = freeRegionBucketsUsed >> bucketIndex; + + // Loop through each bucket that has free regions in it, based on bits set in freeRegionBucketsUsed bitmap. + while(bucketMask) + { + BUCKET_BITMASK_T indexAdd = __builtin_ctzll(bucketMask); + bucketIndex += indexAdd; + bucketMask >>= indexAdd; + assert(bucketIndex >= 0); + assert(bucketIndex <= NUM_FREE_BUCKETS-1); + assert(freeRegionBucketsUsed & (((BUCKET_BITMASK_T)1) << bucketIndex)); + + Region *freeRegion = freeRegionBuckets[bucketIndex].next; + assert(freeRegion); + if (freeRegion != &freeRegionBuckets[bucketIndex]) + { + void *ptr = attempt_allocate(freeRegion, alignment, size); + if (ptr) + return ptr; + + // We were not able to allocate from the first region found in this bucket, so penalize + // the region by cycling it to the end of the doubly circular linked list. (constant time) + // This provides a randomized guarantee that when performing allocations of size k to a + // bucket of [k-something, k+something] range, we will not always attempt to satisfy the + // allocation from the same available region at the front of the list, but we try each + // region in turn. + unlink_from_free_list(freeRegion); + prepend_to_free_list(freeRegion, &freeRegionBuckets[bucketIndex]); + // But do not stick around to attempt to look at other regions in this bucket - move + // to search the next populated bucket index if this did not fit. This gives a practical + // "allocation in constant time" guarantee, since the next higher bucket will only have + // regions that are all of strictly larger size than the requested allocation. Only if + // there is a difficult alignment requirement we may fail to perform the allocation from + // a region in the next bucket, and if so, we keep trying higher buckets until one of them + // works. + ++bucketIndex; + bucketMask >>= 1; + } + else + { + // This bucket was not populated after all with any regions, + // but we just had a stale bit set to mark a populated bucket. + // Reset the bit to update latest status so that we do not + // redundantly look at this bucket again. + freeRegionBucketsUsed &= ~(((BUCKET_BITMASK_T)1) << bucketIndex); + bucketMask ^= 1; + } + // Instead of recomputing bucketMask from scratch at the end of each loop, it is updated as we go, + // to avoid undefined behavior with (x >> 32)/(x >> 64) when bucketIndex reaches 32/64, (the shift would comes out as a no-op instead of 0). + + assert((bucketIndex == NUM_FREE_BUCKETS && bucketMask == 0) || (bucketMask == freeRegionBucketsUsed >> bucketIndex)); + } + + // None of the buckets were able to accommodate an allocation. If this happens we are almost out of memory. + // The largest bucket might contain some suitable regions, but we only looked at one region in that bucket, so + // as a last resort, loop through more free regions in the bucket that represents the largest allocations available. + // But only if the bucket representing largest allocations available is not any of the first thirty buckets, + // these represent allocatable areas less than <1024 bytes - which could be a lot of scrap. + // In such case, prefer to sbrk() in more memory right away. + int largestBucketIndex = NUM_FREE_BUCKETS - 1 - __builtin_clzll(freeRegionBucketsUsed); + // freeRegion will be null if there is absolutely no memory left. (all buckets are 100% used) + Region *freeRegion = freeRegionBucketsUsed ? freeRegionBuckets[largestBucketIndex].next : 0; + if (freeRegionBucketsUsed >> 30) + { + // Look only at a constant number of regions in this bucket max, to avoid bad worst case behavior. + // If this many regions cannot find free space, we give up and prefer to sbrk() more instead. + const int maxRegionsToTryBeforeGivingUp = 99; + int numTriesLeft = maxRegionsToTryBeforeGivingUp; + while(freeRegion != &freeRegionBuckets[largestBucketIndex] && numTriesLeft-- > 0) + { + void *ptr = attempt_allocate(freeRegion, alignment, size); + if (ptr) + return ptr; + freeRegion = freeRegion->next; + } + } + + // We were unable to find a free memory region. Must sbrk() in more memory! + size_t numBytesToClaim = size+sizeof(Region)*3; + assert(numBytesToClaim > size); // 32-bit wraparound should not happen here, allocation size has been validated above! + bool success = claim_more_memory(numBytesToClaim); + if (success) + return allocate_memory(alignment, size); // Recurse back to itself to try again + + // also sbrk() failed, we are really really constrained :( As a last resort, go back to looking at the + // bucket we already looked at above, continuing where the above search left off - perhaps there are + // regions we overlooked the first time that might be able to satisfy the allocation. + if (freeRegion) + { + while(freeRegion != &freeRegionBuckets[largestBucketIndex]) + { + void *ptr = attempt_allocate(freeRegion, alignment, size); + if (ptr) + return ptr; + freeRegion = freeRegion->next; + } + } + +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('Could not find a free memory block!')); +#endif + + return 0; +} + +static +void *emmalloc_memalign(size_t alignment, size_t size) +{ + MALLOC_ACQUIRE(); + void *ptr = allocate_memory(alignment, size); + MALLOC_RELEASE(); + return ptr; +} + +#if 0 +void * EMMALLOC_EXPORT memalign(size_t alignment, size_t size) +{ + return emmalloc_memalign(alignment, size); +} +#endif + +void * EMMALLOC_EXPORT aligned_alloc(size_t alignment, size_t size) +{ + if ((alignment % sizeof(void *) != 0) || (size % alignment) != 0) + return 0; + return emmalloc_memalign(alignment, size); +} + +static +void *emmalloc_malloc(size_t size) +{ + return emmalloc_memalign(MALLOC_ALIGNMENT, size); +} + +void * EMMALLOC_EXPORT malloc(size_t size) +{ + return emmalloc_malloc(size); +} + +static +size_t emmalloc_usable_size(void *ptr) +{ + if (!ptr) + return 0; + + uint8_t *regionStartPtr = (uint8_t*)ptr - sizeof(size_t); + Region *region = (Region*)(regionStartPtr); + assert(HAS_ALIGNMENT(region, sizeof(size_t))); + + MALLOC_ACQUIRE(); + + size_t size = region->size; + assert(size >= sizeof(Region)); + assert(region_is_in_use(region)); + + MALLOC_RELEASE(); + + return size - REGION_HEADER_SIZE; +} + +size_t EMMALLOC_EXPORT malloc_usable_size(void *ptr) +{ + return emmalloc_usable_size(ptr); +} + +static +void emmalloc_free(void *ptr) +{ +#ifdef EMMALLOC_MEMVALIDATE + emmalloc_validate_memory_regions(); +#endif + + if (!ptr) + return; + +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('free(ptr=0x'+($0>>>0).toString(16)+')'), ptr); +#endif + + uint8_t *regionStartPtr = (uint8_t*)ptr - sizeof(size_t); + Region *region = (Region*)(regionStartPtr); + assert(HAS_ALIGNMENT(region, sizeof(size_t))); + + MALLOC_ACQUIRE(); + + size_t size = region->size; +#ifdef EMMALLOC_VERBOSE + if (size < sizeof(Region) || !region_is_in_use(region)) + { + if (debug_region_is_consistent(region)) + // LLVM wasm backend bug: cannot use MAIN_THREAD_ASYNC_EM_ASM() here, that generates internal compiler error + // Reproducible by running e.g. other.test_alloc_3GB + EM_ASM(console.error('Double free at region ptr 0x' + ($0>>>0).toString(16) + ', region->size: 0x' + ($1>>>0).toString(16) + ', region->sizeAtCeiling: 0x' + ($2>>>0).toString(16) + ')'), region, size, region_ceiling_size(region)); + else + MAIN_THREAD_ASYNC_EM_ASM(console.error('Corrupt region at region ptr 0x' + ($0>>>0).toString(16) + ' region->size: 0x' + ($1>>>0).toString(16) + ', region->sizeAtCeiling: 0x' + ($2>>>0).toString(16) + ')'), region, size, region_ceiling_size(region)); + } +#endif + assert(size >= sizeof(Region)); + assert(region_is_in_use(region)); + +#ifdef __EMSCRIPTEN_TRACING__ + emscripten_trace_record_free(region); +#endif + + // Check merging with left side + size_t prevRegionSizeField = ((size_t*)region)[-1]; + size_t prevRegionSize = prevRegionSizeField & ~FREE_REGION_FLAG; + if (prevRegionSizeField != prevRegionSize) // Previous region is free? + { + Region *prevRegion = (Region*)((uint8_t*)region - prevRegionSize); + assert(debug_region_is_consistent(prevRegion)); + unlink_from_free_list(prevRegion); + regionStartPtr = (uint8_t*)prevRegion; + size += prevRegionSize; + } + + // Check merging with right side + Region *nextRegion = next_region(region); + assert(debug_region_is_consistent(nextRegion)); + size_t sizeAtEnd = *(size_t*)region_payload_end_ptr(nextRegion); + if (nextRegion->size != sizeAtEnd) + { + unlink_from_free_list(nextRegion); + size += nextRegion->size; + } + + create_free_region(regionStartPtr, size); + link_to_free_list((Region*)regionStartPtr); + + MALLOC_RELEASE(); + +#ifdef EMMALLOC_MEMVALIDATE + emmalloc_validate_memory_regions(); +#endif +} + +void EMMALLOC_EXPORT free(void *ptr) +{ + emmalloc_free(ptr); +} + +// Can be called to attempt to increase or decrease the size of the given region +// to a new size (in-place). Returns 1 if resize succeeds, and 0 on failure. +static int attempt_region_resize(Region *region, size_t size) +{ + ASSERT_MALLOC_IS_ACQUIRED(); + assert(size > 0); + assert(HAS_ALIGNMENT(size, sizeof(size_t))); + +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('attempt_region_resize(region=0x' + ($0>>>0).toString(16) + ', size=' + ($1>>>0) + ' bytes)'), region, size); +#endif + + // First attempt to resize this region, if the next region that follows this one + // is a free region. + Region *nextRegion = next_region(region); + uint8_t *nextRegionEndPtr = (uint8_t*)nextRegion + nextRegion->size; + size_t sizeAtCeiling = ((size_t*)nextRegionEndPtr)[-1]; + if (nextRegion->size != sizeAtCeiling) // Next region is free? + { + assert(region_is_free(nextRegion)); + uint8_t *newNextRegionStartPtr = (uint8_t*)region + size; + assert(HAS_ALIGNMENT(newNextRegionStartPtr, sizeof(size_t))); + // Next region does not shrink to too small size? + if (newNextRegionStartPtr + sizeof(Region) <= nextRegionEndPtr) + { + unlink_from_free_list(nextRegion); + create_free_region(newNextRegionStartPtr, nextRegionEndPtr - newNextRegionStartPtr); + link_to_free_list((Region*)newNextRegionStartPtr); + create_used_region(region, newNextRegionStartPtr - (uint8_t*)region); + return 1; + } + // If we remove the next region altogether, allocation is satisfied? + if (newNextRegionStartPtr <= nextRegionEndPtr) + { + unlink_from_free_list(nextRegion); + create_used_region(region, region->size + nextRegion->size); + return 1; + } + } + else + { + // Next region is an used region - we cannot change its starting address. However if we are shrinking the + // size of this region, we can create a new free region between this and the next used region. + if (size + sizeof(Region) <= region->size) + { + size_t freeRegionSize = region->size - size; + create_used_region(region, size); + Region *freeRegion = (Region *)((uint8_t*)region + size); + create_free_region(freeRegion, freeRegionSize); + link_to_free_list(freeRegion); + return 1; + } + else if (size <= region->size) + { + // Caller was asking to shrink the size, but due to not being able to fit a full Region in the shrunk + // area, we cannot actually do anything. This occurs if the shrink amount is really small. In such case, + // just call it success without doing any work. + return 1; + } + } +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('attempt_region_resize failed.')); +#endif + return 0; +} + +static int acquire_and_attempt_region_resize(Region *region, size_t size) +{ + MALLOC_ACQUIRE(); + int success = attempt_region_resize(region, size); + MALLOC_RELEASE(); + return success; +} + +static +void *emmalloc_aligned_realloc(void *ptr, size_t alignment, size_t size) +{ +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('aligned_realloc(ptr=0x' + ($0>>>0).toString(16) + ', alignment=' + $1 + ', size=' + ($2>>>0)), ptr, alignment, size); +#endif + + if (!ptr) + return emmalloc_memalign(alignment, size); + + if (size == 0) + { + free(ptr); + return 0; + } + + if (size > MAX_ALLOC_SIZE) + { +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('Allocation failed: attempted allocation size is too large: ' + ($0 >>> 0) + 'bytes! (negative integer wraparound?)'), size); +#endif + return 0; + } + + assert(IS_POWER_OF_2(alignment)); + // aligned_realloc() cannot be used to ask to change the alignment of a pointer. + assert(HAS_ALIGNMENT(ptr, alignment)); + size = validate_alloc_size(size); + + // Calculate the region start address of the original allocation + Region *region = (Region*)((uint8_t*)ptr - sizeof(size_t)); + + // First attempt to resize the given region to avoid having to copy memory around + if (acquire_and_attempt_region_resize(region, size + REGION_HEADER_SIZE)) + { +#ifdef __EMSCRIPTEN_TRACING__ + emscripten_trace_record_reallocation(ptr, ptr, size); +#endif + return ptr; + } + + // If resize failed, we must allocate a new region, copy the data over, and then + // free the old region. + void *newptr = emmalloc_memalign(alignment, size); + if (newptr) + { + memcpy(newptr, ptr, MIN(size, region->size - REGION_HEADER_SIZE)); + free(ptr); + } + // N.B. If there is not enough memory, the old memory block should not be freed and + // null pointer is returned. + return newptr; +} + +#if 0 +void * EMMALLOC_EXPORT aligned_realloc(void *ptr, size_t alignment, size_t size) +{ + return emmalloc_aligned_realloc(ptr, alignment, size); +} +#endif + +#if 0 +// realloc_try() is like realloc(), but only attempts to try to resize the existing memory +// area. If resizing the existing memory area fails, then realloc_try() will return 0 +// (the original memory block is not freed or modified). If resizing succeeds, previous +// memory contents will be valid up to min(old length, new length) bytes. +void *emmalloc_realloc_try(void *ptr, size_t size) +{ + if (!ptr) + return 0; + + if (size == 0) + { + free(ptr); + return 0; + } + + if (size > MAX_ALLOC_SIZE) + { +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('Allocation failed: attempted allocation size is too large: ' + ($0 >>> 0) + 'bytes! (negative integer wraparound?)'), size); +#endif + return 0; + } + + size = validate_alloc_size(size); + + // Calculate the region start address of the original allocation + Region *region = (Region*)((uint8_t*)ptr - sizeof(size_t)); + + // Attempt to resize the given region to avoid having to copy memory around + int success = acquire_and_attempt_region_resize(region, size + REGION_HEADER_SIZE); +#ifdef __EMSCRIPTEN_TRACING__ + if (success) + emscripten_trace_record_reallocation(ptr, ptr, size); +#endif + return success ? ptr : 0; +} + +// emmalloc_aligned_realloc_uninitialized() is like aligned_realloc(), but old memory contents +// will be undefined after reallocation. (old memory is not preserved in any case) +void *emmalloc_aligned_realloc_uninitialized(void *ptr, size_t alignment, size_t size) +{ + if (!ptr) + return emmalloc_memalign(alignment, size); + + if (size == 0) + { + free(ptr); + return 0; + } + + if (size > MAX_ALLOC_SIZE) + { +#ifdef EMMALLOC_VERBOSE + MAIN_THREAD_ASYNC_EM_ASM(console.log('Allocation failed: attempted allocation size is too large: ' + ($0 >>> 0) + 'bytes! (negative integer wraparound?)'), size); +#endif + return 0; + } + + size = validate_alloc_size(size); + + // Calculate the region start address of the original allocation + Region *region = (Region*)((uint8_t*)ptr - sizeof(size_t)); + + // First attempt to resize the given region to avoid having to copy memory around + if (acquire_and_attempt_region_resize(region, size + REGION_HEADER_SIZE)) + { +#ifdef __EMSCRIPTEN_TRACING__ + emscripten_trace_record_reallocation(ptr, ptr, size); +#endif + return ptr; + } + + // If resize failed, drop the old region and allocate a new region. Memory is not + // copied over + free(ptr); + return emmalloc_memalign(alignment, size); +} +#endif + +static +void *emmalloc_realloc(void *ptr, size_t size) +{ + return emmalloc_aligned_realloc(ptr, MALLOC_ALIGNMENT, size); +} + +void * EMMALLOC_EXPORT realloc(void *ptr, size_t size) +{ + return emmalloc_realloc(ptr, size); +} + +#if 0 +// realloc_uninitialized() is like realloc(), but old memory contents +// will be undefined after reallocation. (old memory is not preserved in any case) +void *emmalloc_realloc_uninitialized(void *ptr, size_t size) +{ + return emmalloc_aligned_realloc_uninitialized(ptr, MALLOC_ALIGNMENT, size); +} +#endif + +static +int emmalloc_posix_memalign(void **memptr, size_t alignment, size_t size) +{ + assert(memptr); + if (alignment % sizeof(void *) != 0) + return 22/* EINVAL*/; + *memptr = emmalloc_memalign(alignment, size); + return *memptr ? 0 : 12/*ENOMEM*/; +} + +int EMMALLOC_EXPORT posix_memalign(void **memptr, size_t alignment, size_t size) +{ + return emmalloc_posix_memalign(memptr, alignment, size); +} + +static +void *emmalloc_calloc(size_t num, size_t size) +{ + size_t bytes = num*size; + void *ptr = emmalloc_memalign(MALLOC_ALIGNMENT, bytes); + if (ptr) + memset(ptr, 0, bytes); + return ptr; +} + +void * EMMALLOC_EXPORT calloc(size_t num, size_t size) +{ + return emmalloc_calloc(num, size); +} + +#if 0 +static int count_linked_list_size(Region *list) +{ + int size = 1; + for(Region *i = list->next; i != list; list = list->next) + ++size; + return size; +} + +static size_t count_linked_list_space(Region *list) +{ + size_t space = 0; + for(Region *i = list->next; i != list; list = list->next) + space += region_payload_end_ptr(i) - region_payload_start_ptr(i); + return space; +} + +struct mallinfo emmalloc_mallinfo() +{ + MALLOC_ACQUIRE(); + + struct mallinfo info; + // Non-mmapped space allocated (bytes): For emmalloc, + // let's define this as the difference between heap size and dynamic top end. + info.arena = emscripten_get_heap_size() - (size_t)sbrk(0); + // Number of "ordinary" blocks. Let's define this as the number of highest + // size blocks. (subtract one from each, since there is a sentinel node in each list) + info.ordblks = count_linked_list_size(&freeRegionBuckets[NUM_FREE_BUCKETS-1])-1; + // Number of free "fastbin" blocks. For emmalloc, define this as the number + // of blocks that are not in the largest pristine block. + info.smblks = 0; + // The total number of bytes in free "fastbin" blocks. + info.fsmblks = 0; + for(int i = 0; i < NUM_FREE_BUCKETS-1; ++i) + { + info.smblks += count_linked_list_size(&freeRegionBuckets[i])-1; + info.fsmblks += count_linked_list_space(&freeRegionBuckets[i]); + } + + info.hblks = 0; // Number of mmapped regions: always 0. (no mmap support) + info.hblkhd = 0; // Amount of bytes in mmapped regions: always 0. (no mmap support) + + // Walk through all the heap blocks to report the following data: + // The "highwater mark" for allocated space—that is, the maximum amount of + // space that was ever allocated. Emmalloc does not want to pay code to + // track this, so this is only reported from current allocation data, and + // may not be accurate. + info.usmblks = 0; + info.uordblks = 0; // The total number of bytes used by in-use allocations. + info.fordblks = 0; // The total number of bytes in free blocks. + // The total amount of releasable free space at the top of the heap. + // This is the maximum number of bytes that could ideally be released by malloc_trim(3). + Region *lastActualRegion = prev_region((Region*)(listOfAllRegions->endPtr - sizeof(Region))); + info.keepcost = region_is_free(lastActualRegion) ? lastActualRegion->size : 0; + + RootRegion *root = listOfAllRegions; + while(root) + { + Region *r = (Region*)root; + assert(debug_region_is_consistent(r)); + uint8_t *lastRegionEnd = root->endPtr; + while((uint8_t*)r < lastRegionEnd) + { + assert(debug_region_is_consistent(r)); + + if (region_is_free(r)) + { + // Count only the payload of the free block towards free memory. + info.fordblks += region_payload_end_ptr(r) - region_payload_start_ptr(r); + // But the header data of the free block goes towards used memory. + info.uordblks += REGION_HEADER_SIZE; + } + else + { + info.uordblks += r->size; + } + // Update approximate watermark data + info.usmblks = MAX(info.usmblks, (intptr_t)r + r->size); + + if (r->size == 0) + break; + r = next_region(r); + } + root = root->next; + } + + MALLOC_RELEASE(); + return info; +} + +struct mallinfo EMMALLOC_EXPORT mallinfo() +{ + return emmalloc_mallinfo(); +} + +// Note! This function is not fully multithreadin safe: while this function is running, other threads should not be +// allowed to call sbrk()! +static int trim_dynamic_heap_reservation(size_t pad) +{ + ASSERT_MALLOC_IS_ACQUIRED(); + + if (!listOfAllRegions) + return 0; // emmalloc is not controlling any dynamic memory at all - cannot release memory. + uint8_t *previousSbrkEndAddress = listOfAllRegions->endPtr; + assert(sbrk(0) == previousSbrkEndAddress); + size_t lastMemoryRegionSize = ((size_t*)previousSbrkEndAddress)[-1]; + assert(lastMemoryRegionSize == 16); // // The last memory region should be a sentinel node of exactly 16 bytes in size. + Region *endSentinelRegion = (Region*)(previousSbrkEndAddress - sizeof(Region)); + Region *lastActualRegion = prev_region(endSentinelRegion); + + // Round padding up to multiple of 4 bytes to keep sbrk() and memory region alignment intact. + // Also have at least 8 bytes of payload so that we can form a full free region. + size_t newRegionSize = (size_t)ALIGN_UP(pad, 4); + if (pad > 0) + newRegionSize += sizeof(Region) - (newRegionSize - pad); + + if (!region_is_free(lastActualRegion) || lastActualRegion->size <= newRegionSize) + return 0; // Last actual region is in use, or caller desired to leave more free memory intact than there is. + + // This many bytes will be shrunk away. + size_t shrinkAmount = lastActualRegion->size - newRegionSize; + assert(HAS_ALIGNMENT(shrinkAmount, 4)); + + unlink_from_free_list(lastActualRegion); + // If pad == 0, we should delete the last free region altogether. If pad > 0, + // shrink the last free region to the desired size. + if (newRegionSize > 0) + { + create_free_region(lastActualRegion, newRegionSize); + link_to_free_list(lastActualRegion); + } + + // Recreate the sentinel region at the end of the last free region + endSentinelRegion = (Region*)((uint8_t*)lastActualRegion + newRegionSize); + create_used_region(endSentinelRegion, sizeof(Region)); + + // And update the size field of the whole region block. + listOfAllRegions->endPtr = (uint8_t*)endSentinelRegion + sizeof(Region); + + // Finally call sbrk() to shrink the memory area. + void *oldSbrk = sbrk(-(intptr_t)shrinkAmount); + assert((intptr_t)oldSbrk != -1); // Shrinking with sbrk() should never fail. + assert(oldSbrk == previousSbrkEndAddress); // Another thread should not have raced to increase sbrk() on us! + + // All successful, and we actually trimmed memory! + return 1; +} + +int emmalloc_trim(size_t pad) +{ + MALLOC_ACQUIRE(); + int success = trim_dynamic_heap_reservation(pad); + MALLOC_RELEASE(); + return success; +} + +int EMMALLOC_EXPORT malloc_trim(size_t pad) +{ + return emmalloc_trim(pad); +} + +size_t emmalloc_dynamic_heap_size() +{ + size_t dynamicHeapSize = 0; + + MALLOC_ACQUIRE(); + RootRegion *root = listOfAllRegions; + while(root) + { + dynamicHeapSize += root->endPtr - (uint8_t*)root; + root = root->next; + } + MALLOC_RELEASE(); + return dynamicHeapSize; +} + +size_t emmalloc_free_dynamic_memory() +{ + size_t freeDynamicMemory = 0; + + int bucketIndex = 0; + + MALLOC_ACQUIRE(); + BUCKET_BITMASK_T bucketMask = freeRegionBucketsUsed; + + // Loop through each bucket that has free regions in it, based on bits set in freeRegionBucketsUsed bitmap. + while(bucketMask) + { + BUCKET_BITMASK_T indexAdd = __builtin_ctzll(bucketMask); + bucketIndex += indexAdd; + bucketMask >>= indexAdd; + for(Region *freeRegion = freeRegionBuckets[bucketIndex].next; + freeRegion != &freeRegionBuckets[bucketIndex]; + freeRegion = freeRegion->next) + { + freeDynamicMemory += freeRegion->size - REGION_HEADER_SIZE; + } + ++bucketIndex; + bucketMask >>= 1; + } + MALLOC_RELEASE(); + return freeDynamicMemory; +} + +size_t emmalloc_compute_free_dynamic_memory_fragmentation_map(size_t freeMemorySizeMap[32]) +{ + memset((void*)freeMemorySizeMap, 0, sizeof(freeMemorySizeMap[0])*32); + + size_t numFreeMemoryRegions = 0; + int bucketIndex = 0; + MALLOC_ACQUIRE(); + BUCKET_BITMASK_T bucketMask = freeRegionBucketsUsed; + + // Loop through each bucket that has free regions in it, based on bits set in freeRegionBucketsUsed bitmap. + while(bucketMask) + { + BUCKET_BITMASK_T indexAdd = __builtin_ctzll(bucketMask); + bucketIndex += indexAdd; + bucketMask >>= indexAdd; + for(Region *freeRegion = freeRegionBuckets[bucketIndex].next; + freeRegion != &freeRegionBuckets[bucketIndex]; + freeRegion = freeRegion->next) + { + ++numFreeMemoryRegions; + size_t freeDynamicMemory = freeRegion->size - REGION_HEADER_SIZE; + if (freeDynamicMemory > 0) + ++freeMemorySizeMap[31-__builtin_clz(freeDynamicMemory)]; + else + ++freeMemorySizeMap[0]; + } + ++bucketIndex; + bucketMask >>= 1; + } + MALLOC_RELEASE(); + return numFreeMemoryRegions; +} + +size_t emmalloc_unclaimed_heap_memory(void) { + return emscripten_get_heap_max() - (size_t)sbrk(0); +} +#endif + +// Define these to satisfy musl references. +void *__libc_malloc(size_t) __attribute__((alias("malloc"))); +void __libc_free(void *) __attribute__((alias("free"))); +void *__libc_calloc(size_t nmemb, size_t size) __attribute__((alias("calloc"))); |