From 384c0131ccda2656dec23a0416ad3f14101151a7 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Wed, 3 Jun 2020 19:22:12 -0400
Subject: move oldmalloc to its own directory under src/malloc

this sets the stage for replacement, and makes it practical to keep
oldmalloc around as a build option for a while if that ends up being
useful.

only the files which are actually part of the implementation are
moved. memalign and posix_memalign are entirely generic. in theory
calloc could be pulled out too, but it's useful to have it tied to the
implementation so as to optimize out unnecessary memset when
implementation details make it possible to know the memory is already
clear.
---
 src/malloc/malloc.c | 550 ----------------------------------------------------
 1 file changed, 550 deletions(-)
 delete mode 100644 src/malloc/malloc.c

(limited to 'src/malloc/malloc.c')

diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c
deleted file mode 100644
index df3ea1be..00000000
--- a/src/malloc/malloc.c
+++ /dev/null
@@ -1,550 +0,0 @@
-#define _GNU_SOURCE
-#include <stdlib.h>
-#include <string.h>
-#include <limits.h>
-#include <stdint.h>
-#include <errno.h>
-#include <sys/mman.h>
-#include "libc.h"
-#include "atomic.h"
-#include "pthread_impl.h"
-#include "malloc_impl.h"
-
-#if defined(__GNUC__) && defined(__PIC__)
-#define inline inline __attribute__((always_inline))
-#endif
-
-static struct {
-	volatile uint64_t binmap;
-	struct bin bins[64];
-	volatile int split_merge_lock[2];
-} mal;
-
-int __malloc_replaced;
-
-/* Synchronization tools */
-
-static inline void lock(volatile int *lk)
-{
-	int need_locks = libc.need_locks;
-	if (need_locks) {
-		while(a_swap(lk, 1)) __wait(lk, lk+1, 1, 1);
-		if (need_locks < 0) libc.need_locks = 0;
-	}
-}
-
-static inline void unlock(volatile int *lk)
-{
-	if (lk[0]) {
-		a_store(lk, 0);
-		if (lk[1]) __wake(lk, 1, 1);
-	}
-}
-
-static inline void lock_bin(int i)
-{
-	lock(mal.bins[i].lock);
-	if (!mal.bins[i].head)
-		mal.bins[i].head = mal.bins[i].tail = BIN_TO_CHUNK(i);
-}
-
-static inline void unlock_bin(int i)
-{
-	unlock(mal.bins[i].lock);
-}
-
-static int first_set(uint64_t x)
-{
-#if 1
-	return a_ctz_64(x);
-#else
-	static const char debruijn64[64] = {
-		0, 1, 2, 53, 3, 7, 54, 27, 4, 38, 41, 8, 34, 55, 48, 28,
-		62, 5, 39, 46, 44, 42, 22, 9, 24, 35, 59, 56, 49, 18, 29, 11,
-		63, 52, 6, 26, 37, 40, 33, 47, 61, 45, 43, 21, 23, 58, 17, 10,
-		51, 25, 36, 32, 60, 20, 57, 16, 50, 31, 19, 15, 30, 14, 13, 12
-	};
-	static const char debruijn32[32] = {
-		0, 1, 23, 2, 29, 24, 19, 3, 30, 27, 25, 11, 20, 8, 4, 13,
-		31, 22, 28, 18, 26, 10, 7, 12, 21, 17, 9, 6, 16, 5, 15, 14
-	};
-	if (sizeof(long) < 8) {
-		uint32_t y = x;
-		if (!y) {
-			y = x>>32;
-			return 32 + debruijn32[(y&-y)*0x076be629 >> 27];
-		}
-		return debruijn32[(y&-y)*0x076be629 >> 27];
-	}
-	return debruijn64[(x&-x)*0x022fdd63cc95386dull >> 58];
-#endif
-}
-
-static const unsigned char bin_tab[60] = {
-	            32,33,34,35,36,36,37,37,38,38,39,39,
-	40,40,40,40,41,41,41,41,42,42,42,42,43,43,43,43,
-	44,44,44,44,44,44,44,44,45,45,45,45,45,45,45,45,
-	46,46,46,46,46,46,46,46,47,47,47,47,47,47,47,47,
-};
-
-static int bin_index(size_t x)
-{
-	x = x / SIZE_ALIGN - 1;
-	if (x <= 32) return x;
-	if (x < 512) return bin_tab[x/8-4];
-	if (x > 0x1c00) return 63;
-	return bin_tab[x/128-4] + 16;
-}
-
-static int bin_index_up(size_t x)
-{
-	x = x / SIZE_ALIGN - 1;
-	if (x <= 32) return x;
-	x--;
-	if (x < 512) return bin_tab[x/8-4] + 1;
-	return bin_tab[x/128-4] + 17;
-}
-
-#if 0
-void __dump_heap(int x)
-{
-	struct chunk *c;
-	int i;
-	for (c = (void *)mal.heap; CHUNK_SIZE(c); c = NEXT_CHUNK(c))
-		fprintf(stderr, "base %p size %zu (%d) flags %d/%d\n",
-			c, CHUNK_SIZE(c), bin_index(CHUNK_SIZE(c)),
-			c->csize & 15,
-			NEXT_CHUNK(c)->psize & 15);
-	for (i=0; i<64; i++) {
-		if (mal.bins[i].head != BIN_TO_CHUNK(i) && mal.bins[i].head) {
-			fprintf(stderr, "bin %d: %p\n", i, mal.bins[i].head);
-			if (!(mal.binmap & 1ULL<<i))
-				fprintf(stderr, "missing from binmap!\n");
-		} else if (mal.binmap & 1ULL<<i)
-			fprintf(stderr, "binmap wrongly contains %d!\n", i);
-	}
-}
-#endif
-
-/* This function returns true if the interval [old,new]
- * intersects the 'len'-sized interval below &libc.auxv
- * (interpreted as the main-thread stack) or below &b
- * (the current stack). It is used to defend against
- * buggy brk implementations that can cross the stack. */
-
-static int traverses_stack_p(uintptr_t old, uintptr_t new)
-{
-	const uintptr_t len = 8<<20;
-	uintptr_t a, b;
-
-	b = (uintptr_t)libc.auxv;
-	a = b > len ? b-len : 0;
-	if (new>a && old<b) return 1;
-
-	b = (uintptr_t)&b;
-	a = b > len ? b-len : 0;
-	if (new>a && old<b) return 1;
-
-	return 0;
-}
-
-/* Expand the heap in-place if brk can be used, or otherwise via mmap,
- * using an exponential lower bound on growth by mmap to make
- * fragmentation asymptotically irrelevant. The size argument is both
- * an input and an output, since the caller needs to know the size
- * allocated, which will be larger than requested due to page alignment
- * and mmap minimum size rules. The caller is responsible for locking
- * to prevent concurrent calls. */
-
-static void *__expand_heap(size_t *pn)
-{
-	static uintptr_t brk;
-	static unsigned mmap_step;
-	size_t n = *pn;
-
-	if (n > SIZE_MAX/2 - PAGE_SIZE) {
-		errno = ENOMEM;
-		return 0;
-	}
-	n += -n & PAGE_SIZE-1;
-
-	if (!brk) {
-		brk = __syscall(SYS_brk, 0);
-		brk += -brk & PAGE_SIZE-1;
-	}
-
-	if (n < SIZE_MAX-brk && !traverses_stack_p(brk, brk+n)
-	    && __syscall(SYS_brk, brk+n)==brk+n) {
-		*pn = n;
-		brk += n;
-		return (void *)(brk-n);
-	}
-
-	size_t min = (size_t)PAGE_SIZE << mmap_step/2;
-	if (n < min) n = min;
-	void *area = __mmap(0, n, PROT_READ|PROT_WRITE,
-		MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
-	if (area == MAP_FAILED) return 0;
-	*pn = n;
-	mmap_step++;
-	return area;
-}
-
-static struct chunk *expand_heap(size_t n)
-{
-	static void *end;
-	void *p;
-	struct chunk *w;
-
-	/* The argument n already accounts for the caller's chunk
-	 * overhead needs, but if the heap can't be extended in-place,
-	 * we need room for an extra zero-sized sentinel chunk. */
-	n += SIZE_ALIGN;
-
-	p = __expand_heap(&n);
-	if (!p) return 0;
-
-	/* If not just expanding existing space, we need to make a
-	 * new sentinel chunk below the allocated space. */
-	if (p != end) {
-		/* Valid/safe because of the prologue increment. */
-		n -= SIZE_ALIGN;
-		p = (char *)p + SIZE_ALIGN;
-		w = MEM_TO_CHUNK(p);
-		w->psize = 0 | C_INUSE;
-	}
-
-	/* Record new heap end and fill in footer. */
-	end = (char *)p + n;
-	w = MEM_TO_CHUNK(end);
-	w->psize = n | C_INUSE;
-	w->csize = 0 | C_INUSE;
-
-	/* Fill in header, which may be new or may be replacing a
-	 * zero-size sentinel header at the old end-of-heap. */
-	w = MEM_TO_CHUNK(p);
-	w->csize = n | C_INUSE;
-
-	return w;
-}
-
-static int adjust_size(size_t *n)
-{
-	/* Result of pointer difference must fit in ptrdiff_t. */
-	if (*n-1 > PTRDIFF_MAX - SIZE_ALIGN - PAGE_SIZE) {
-		if (*n) {
-			errno = ENOMEM;
-			return -1;
-		} else {
-			*n = SIZE_ALIGN;
-			return 0;
-		}
-	}
-	*n = (*n + OVERHEAD + SIZE_ALIGN - 1) & SIZE_MASK;
-	return 0;
-}
-
-static void unbin(struct chunk *c, int i)
-{
-	if (c->prev == c->next)
-		a_and_64(&mal.binmap, ~(1ULL<<i));
-	c->prev->next = c->next;
-	c->next->prev = c->prev;
-	c->csize |= C_INUSE;
-	NEXT_CHUNK(c)->psize |= C_INUSE;
-}
-
-static void bin_chunk(struct chunk *self, int i)
-{
-	self->next = BIN_TO_CHUNK(i);
-	self->prev = mal.bins[i].tail;
-	self->next->prev = self;
-	self->prev->next = self;
-	if (self->prev == BIN_TO_CHUNK(i))
-		a_or_64(&mal.binmap, 1ULL<<i);
-}
-
-static void trim(struct chunk *self, size_t n)
-{
-	size_t n1 = CHUNK_SIZE(self);
-	struct chunk *next, *split;
-
-	if (n >= n1 - DONTCARE) return;
-
-	next = NEXT_CHUNK(self);
-	split = (void *)((char *)self + n);
-
-	split->psize = n | C_INUSE;
-	split->csize = n1-n;
-	next->psize = n1-n;
-	self->csize = n | C_INUSE;
-
-	int i = bin_index(n1-n);
-	lock_bin(i);
-
-	bin_chunk(split, i);
-
-	unlock_bin(i);
-}
-
-void *malloc(size_t n)
-{
-	struct chunk *c;
-	int i, j;
-	uint64_t mask;
-
-	if (adjust_size(&n) < 0) return 0;
-
-	if (n > MMAP_THRESHOLD) {
-		size_t len = n + OVERHEAD + PAGE_SIZE - 1 & -PAGE_SIZE;
-		char *base = __mmap(0, len, PROT_READ|PROT_WRITE,
-			MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
-		if (base == (void *)-1) return 0;
-		c = (void *)(base + SIZE_ALIGN - OVERHEAD);
-		c->csize = len - (SIZE_ALIGN - OVERHEAD);
-		c->psize = SIZE_ALIGN - OVERHEAD;
-		return CHUNK_TO_MEM(c);
-	}
-
-	i = bin_index_up(n);
-	if (i<63 && (mal.binmap & (1ULL<<i))) {
-		lock_bin(i);
-		c = mal.bins[i].head;
-		if (c != BIN_TO_CHUNK(i) && CHUNK_SIZE(c)-n <= DONTCARE) {
-			unbin(c, i);
-			unlock_bin(i);
-			return CHUNK_TO_MEM(c);
-		}
-		unlock_bin(i);
-	}
-	lock(mal.split_merge_lock);
-	for (mask = mal.binmap & -(1ULL<<i); mask; mask -= (mask&-mask)) {
-		j = first_set(mask);
-		lock_bin(j);
-		c = mal.bins[j].head;
-		if (c != BIN_TO_CHUNK(j)) {
-			unbin(c, j);
-			unlock_bin(j);
-			break;
-		}
-		unlock_bin(j);
-	}
-	if (!mask) {
-		c = expand_heap(n);
-		if (!c) {
-			unlock(mal.split_merge_lock);
-			return 0;
-		}
-	}
-	trim(c, n);
-	unlock(mal.split_merge_lock);
-	return CHUNK_TO_MEM(c);
-}
-
-static size_t mal0_clear(char *p, size_t pagesz, size_t n)
-{
-#ifdef __GNUC__
-	typedef uint64_t __attribute__((__may_alias__)) T;
-#else
-	typedef unsigned char T;
-#endif
-	char *pp = p + n;
-	size_t i = (uintptr_t)pp & (pagesz - 1);
-	for (;;) {
-		pp = memset(pp - i, 0, i);
-		if (pp - p < pagesz) return pp - p;
-		for (i = pagesz; i; i -= 2*sizeof(T), pp -= 2*sizeof(T))
-		        if (((T *)pp)[-1] | ((T *)pp)[-2])
-				break;
-	}
-}
-
-void *calloc(size_t m, size_t n)
-{
-	if (n && m > (size_t)-1/n) {
-		errno = ENOMEM;
-		return 0;
-	}
-	n *= m;
-	void *p = malloc(n);
-	if (!p) return p;
-	if (!__malloc_replaced) {
-		if (IS_MMAPPED(MEM_TO_CHUNK(p)))
-			return p;
-		if (n >= PAGE_SIZE)
-			n = mal0_clear(p, PAGE_SIZE, n);
-	}
-	return memset(p, 0, n);
-}
-
-void *realloc(void *p, size_t n)
-{
-	struct chunk *self, *next;
-	size_t n0, n1;
-	void *new;
-
-	if (!p) return malloc(n);
-
-	if (adjust_size(&n) < 0) return 0;
-
-	self = MEM_TO_CHUNK(p);
-	n1 = n0 = CHUNK_SIZE(self);
-
-	if (n<=n0 && n0-n<=DONTCARE) return p;
-
-	if (IS_MMAPPED(self)) {
-		size_t extra = self->psize;
-		char *base = (char *)self - extra;
-		size_t oldlen = n0 + extra;
-		size_t newlen = n + extra;
-		/* Crash on realloc of freed chunk */
-		if (extra & 1) a_crash();
-		if (newlen < PAGE_SIZE && (new = malloc(n-OVERHEAD))) {
-			n0 = n;
-			goto copy_free_ret;
-		}
-		newlen = (newlen + PAGE_SIZE-1) & -PAGE_SIZE;
-		if (oldlen == newlen) return p;
-		base = __mremap(base, oldlen, newlen, MREMAP_MAYMOVE);
-		if (base == (void *)-1)
-			goto copy_realloc;
-		self = (void *)(base + extra);
-		self->csize = newlen - extra;
-		return CHUNK_TO_MEM(self);
-	}
-
-	next = NEXT_CHUNK(self);
-
-	/* Crash on corrupted footer (likely from buffer overflow) */
-	if (next->psize != self->csize) a_crash();
-
-	lock(mal.split_merge_lock);
-
-	size_t nsize = next->csize & C_INUSE ? 0 : CHUNK_SIZE(next);
-	if (n0+nsize >= n) {
-		int i = bin_index(nsize);
-		lock_bin(i);
-		if (!(next->csize & C_INUSE)) {
-			unbin(next, i);
-			unlock_bin(i);
-			next = NEXT_CHUNK(next);
-			self->csize = next->psize = n0+nsize | C_INUSE;
-			trim(self, n);
-			unlock(mal.split_merge_lock);
-			return CHUNK_TO_MEM(self);
-		}
-		unlock_bin(i);
-	}
-	unlock(mal.split_merge_lock);
-
-copy_realloc:
-	/* As a last resort, allocate a new chunk and copy to it. */
-	new = malloc(n-OVERHEAD);
-	if (!new) return 0;
-copy_free_ret:
-	memcpy(new, p, n0-OVERHEAD);
-	free(CHUNK_TO_MEM(self));
-	return new;
-}
-
-void __bin_chunk(struct chunk *self)
-{
-	struct chunk *next = NEXT_CHUNK(self);
-
-	/* Crash on corrupted footer (likely from buffer overflow) */
-	if (next->psize != self->csize) a_crash();
-
-	lock(mal.split_merge_lock);
-
-	size_t osize = CHUNK_SIZE(self), size = osize;
-
-	/* Since we hold split_merge_lock, only transition from free to
-	 * in-use can race; in-use to free is impossible */
-	size_t psize = self->psize & C_INUSE ? 0 : CHUNK_PSIZE(self);
-	size_t nsize = next->csize & C_INUSE ? 0 : CHUNK_SIZE(next);
-
-	if (psize) {
-		int i = bin_index(psize);
-		lock_bin(i);
-		if (!(self->psize & C_INUSE)) {
-			struct chunk *prev = PREV_CHUNK(self);
-			unbin(prev, i);
-			self = prev;
-			size += psize;
-		}
-		unlock_bin(i);
-	}
-	if (nsize) {
-		int i = bin_index(nsize);
-		lock_bin(i);
-		if (!(next->csize & C_INUSE)) {
-			unbin(next, i);
-			next = NEXT_CHUNK(next);
-			size += nsize;
-		}
-		unlock_bin(i);
-	}
-
-	int i = bin_index(size);
-	lock_bin(i);
-
-	self->csize = size;
-	next->psize = size;
-	bin_chunk(self, i);
-	unlock(mal.split_merge_lock);
-
-	/* Replace middle of large chunks with fresh zero pages */
-	if (size > RECLAIM && (size^(size-osize)) > size-osize) {
-		uintptr_t a = (uintptr_t)self + SIZE_ALIGN+PAGE_SIZE-1 & -PAGE_SIZE;
-		uintptr_t b = (uintptr_t)next - SIZE_ALIGN & -PAGE_SIZE;
-#if 1
-		__madvise((void *)a, b-a, MADV_DONTNEED);
-#else
-		__mmap((void *)a, b-a, PROT_READ|PROT_WRITE,
-			MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, -1, 0);
-#endif
-	}
-
-	unlock_bin(i);
-}
-
-static void unmap_chunk(struct chunk *self)
-{
-	size_t extra = self->psize;
-	char *base = (char *)self - extra;
-	size_t len = CHUNK_SIZE(self) + extra;
-	/* Crash on double free */
-	if (extra & 1) a_crash();
-	__munmap(base, len);
-}
-
-void free(void *p)
-{
-	if (!p) return;
-
-	struct chunk *self = MEM_TO_CHUNK(p);
-
-	if (IS_MMAPPED(self))
-		unmap_chunk(self);
-	else
-		__bin_chunk(self);
-}
-
-void __malloc_donate(char *start, char *end)
-{
-	size_t align_start_up = (SIZE_ALIGN-1) & (-(uintptr_t)start - OVERHEAD);
-	size_t align_end_down = (SIZE_ALIGN-1) & (uintptr_t)end;
-
-	/* Getting past this condition ensures that the padding for alignment
-	 * and header overhead will not overflow and will leave a nonzero
-	 * multiple of SIZE_ALIGN bytes between start and end. */
-	if (end - start <= OVERHEAD + align_start_up + align_end_down)
-		return;
-	start += align_start_up + OVERHEAD;
-	end   -= align_end_down;
-
-	struct chunk *c = MEM_TO_CHUNK(start), *n = MEM_TO_CHUNK(end);
-	c->psize = n->csize = C_INUSE;
-	c->csize = n->psize = C_INUSE | (end-start);
-	__bin_chunk(c);
-}
-- 
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