* [binutils-gdb] elf: Use mmap to map in read-only sections
@ 2024-04-03 16:17 H.J. Lu
0 siblings, 0 replies; only message in thread
From: H.J. Lu @ 2024-04-03 16:17 UTC (permalink / raw)
To: binutils-cvs
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=9ba56acee518492cfe21434b974c807f52ac7950
commit 9ba56acee518492cfe21434b974c807f52ac7950
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Thu Feb 29 11:17:01 2024 -0800
elf: Use mmap to map in read-only sections
There are many linker input files in LLVM debug build with huge string
sections. All these string sections can be treated as read-only. But
linker copies all of them into memory which consumes huge amount of
memory and slows down linker significantly.
Add _bfd_mmap_readonly_persistent and _bfd_mmap_readonly_temporary to
mmap in reado-only sections with size >= 4 * page size.
NB: All string sections in valid ELF inputs must be null terminated.
There is no need to terminate it again and string sections are mmapped
as read-only.
* bfd.c (bfd_mmapped_entry): New.
(bfd_mmapped): Likewise.
(bfd): Add mmapped.
* bfdwin.c (bfd_get_file_window): Use _bfd_pagesize.
* cache.c (cache_bmmap): Remove pagesize_m1 and use pagesize_m1
instead.
* elf.c (bfd_elf_get_str_section): Call
_bfd_mmap_readonly_persistent instead of _bfd_alloc_and_read.
Don't terminate the string section again.
(get_hash_table_data): Call _bfd_mmap_readonly_temporary and
_bfd_munmap_readonly_temporary instead of _bfd_malloc_and_read
and free.
(_bfd_elf_get_dynamic_symbols): Call _bfd_mmap_readonly_persistent
instead of _bfd_alloc_and_read. Don't terminate the string
section again. Call _bfd_mmap_readonly_temporary and
_bfd_munmap_readonly_temporary instead of _bfd_malloc_and_read
and free.
(_bfd_elf_slurp_version_tables): Call _bfd_mmap_readonly_temporary
and _bfd_munmap_readonly_temporary instead of _bfd_malloc_and_read
and free.
* elflink.c (bfd_elf_link_record_dynamic_symbol): Use bfd_malloc
to get the unversioned symbol.
* libbfd-in.h (_bfd_pagesize): New.
(_bfd_pagesize_m1): Likewise.
(_bfd_minimum_mmap_size): Likewise.
(_bfd_mmap_readonly_persistent): Likewise.
(_bfd_mmap_readonly_temporary): Likewise.
(_bfd_munmap_readonly_temporary): Likewise.
* libbfd.c
(bfd_allocate_mmapped_page): New.
(_bfd_mmap_readonly_temporary): Likewise.
(_bfd_munmap_readonly_temporary): Likewise.
(_bfd_mmap_readonly_persistent): Likewise.
(_bfd_pagesize): Likewise.
(_bfd_pagesize_m1): Likewise.
(_bfd_minimum_mmap_size): Likewise.
(bfd_init_pagesize): Likewise.
* lynx-core.c (lynx_core_file_p): Use _bfd_pagesize.
* opncls.c (_bfd_delete_bfd): Munmap tracked mmapped memories.
* sysdep.h (MAP_ANONYMOUS): New. Define if undefined.
* bfd-in2.h: Regenerated.
* libbfd.h: Likewise.
Diff:
---
bfd/bfd-in2.h | 17 +++++++
bfd/bfd.c | 17 +++++++
bfd/bfdwin.c | 8 +--
bfd/cache.c | 7 +--
bfd/elf.c | 79 ++++++++++++++++++++---------
bfd/elflink.c | 16 +++---
bfd/libbfd-in.h | 29 +++++++++++
bfd/libbfd.c | 151 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
bfd/libbfd.h | 29 +++++++++++
bfd/lynx-core.c | 2 +-
bfd/opncls.c | 12 +++++
bfd/sysdep.h | 4 ++
12 files changed, 328 insertions(+), 43 deletions(-)
diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index b332f5adad1..8b86607ec1d 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -1962,6 +1962,20 @@ enum bfd_lto_object_type
lto_fat_ir_object /* A fat LTO IR object. */
};
+struct bfd_mmapped_entry
+ {
+ void *addr;
+ size_t size;
+ };
+
+struct bfd_mmapped
+ {
+ struct bfd_mmapped *next;
+ unsigned int max_entry;
+ unsigned int next_entry;
+ struct bfd_mmapped_entry entries[1];
+ };
+
struct bfd
{
/* The filename the application opened the BFD with. */
@@ -2291,6 +2305,9 @@ struct bfd
/* For input BFDs, the build ID, if the object has one. */
const struct bfd_build_id *build_id;
+
+ /* For input BFDs, mmapped entries. */
+ struct bfd_mmapped *mmapped;
};
static inline const char *
diff --git a/bfd/bfd.c b/bfd/bfd.c
index e579788e42f..8fd86f68e6e 100644
--- a/bfd/bfd.c
+++ b/bfd/bfd.c
@@ -82,6 +82,20 @@ EXTERNAL
. lto_fat_ir_object {* A fat LTO IR object. *}
. };
.
+.struct bfd_mmapped_entry
+. {
+. void *addr;
+. size_t size;
+. };
+.
+.struct bfd_mmapped
+. {
+. struct bfd_mmapped *next;
+. unsigned int max_entry;
+. unsigned int next_entry;
+. struct bfd_mmapped_entry entries[1];
+. };
+.
CODE_FRAGMENT
.struct bfd
@@ -414,6 +428,9 @@ CODE_FRAGMENT
.
. {* For input BFDs, the build ID, if the object has one. *}
. const struct bfd_build_id *build_id;
+.
+. {* For input BFDs, mmapped entries. *}
+. struct bfd_mmapped *mmapped;
.};
.
diff --git a/bfd/bfdwin.c b/bfd/bfdwin.c
index 2919c71b3cb..73e44635bcb 100644
--- a/bfd/bfdwin.c
+++ b/bfd/bfdwin.c
@@ -157,7 +157,7 @@ bfd_get_file_window (bfd *abfd,
bool writable)
{
static int ok_to_map = 1;
- static size_t pagesize;
+ size_t pagesize = _bfd_pagesize;
bfd_window_internal *i = windowp->i;
bfd_size_type size_to_alloc = size;
@@ -167,12 +167,6 @@ bfd_get_file_window (bfd *abfd,
windowp, windowp->data, (unsigned long) windowp->size,
windowp->i, writable);
- /* Make sure we know the page size, so we can be friendly to mmap. */
- if (pagesize == 0)
- pagesize = getpagesize ();
- if (pagesize == 0)
- abort ();
-
if (i == NULL)
{
i = bfd_zmalloc (sizeof (bfd_window_internal));
diff --git a/bfd/cache.c b/bfd/cache.c
index d0e7be293a5..0f994c74239 100644
--- a/bfd/cache.c
+++ b/bfd/cache.c
@@ -494,10 +494,10 @@ cache_bmmap (struct bfd *abfd ATTRIBUTE_UNUSED,
#ifdef HAVE_MMAP
else
{
- static uintptr_t pagesize_m1;
+ uintptr_t pagesize_m1 = _bfd_pagesize_m1;
FILE *f;
file_ptr pg_offset;
- bfd_size_type pg_len;
+ size_t pg_len;
f = bfd_cache_lookup (abfd, CACHE_NO_SEEK_ERROR);
if (f == NULL)
@@ -506,9 +506,6 @@ cache_bmmap (struct bfd *abfd ATTRIBUTE_UNUSED,
return ret;
}
- if (pagesize_m1 == 0)
- pagesize_m1 = getpagesize () - 1;
-
/* Align. */
pg_offset = offset & ~pagesize_m1;
pg_len = (len + (offset - pg_offset) + pagesize_m1) & ~pagesize_m1;
diff --git a/bfd/elf.c b/bfd/elf.c
index f7717547fad..34100d81355 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -289,16 +289,23 @@ bfd_elf_get_str_section (bfd *abfd, unsigned int shindex)
in case the string table is not terminated. */
if (shstrtabsize + 1 <= 1
|| bfd_seek (abfd, offset, SEEK_SET) != 0
- || (shstrtab = _bfd_alloc_and_read (abfd, shstrtabsize + 1,
- shstrtabsize)) == NULL)
+ || (shstrtab
+ = _bfd_mmap_readonly_persistent (abfd, shstrtabsize)) == NULL)
{
/* Once we've failed to read it, make sure we don't keep
trying. Otherwise, we'll keep allocating space for
the string table over and over. */
i_shdrp[shindex]->sh_size = 0;
}
- else
- shstrtab[shstrtabsize] = '\0';
+ else if (shstrtab[shstrtabsize - 1] != '\0')
+ {
+ /* It is an error if a string table isn't terminated. */
+ _bfd_error_handler
+ /* xgettext:c-format */
+ (_("%pB(%pA): string table is corrupt"),
+ abfd, i_shdrp[shindex]->bfd_section);
+ return NULL;
+ }
i_shdrp[shindex]->contents = shstrtab;
}
return (char *) shstrtab;
@@ -1897,6 +1904,8 @@ get_hash_table_data (bfd *abfd, bfd_size_type number,
unsigned char *e_data = NULL;
bfd_vma *i_data = NULL;
bfd_size_type size;
+ void *e_data_addr;
+ size_t e_data_size ATTRIBUTE_UNUSED;
if (ent_size != 4 && ent_size != 8)
return NULL;
@@ -1918,7 +1927,8 @@ get_hash_table_data (bfd *abfd, bfd_size_type number,
return NULL;
}
- e_data = _bfd_malloc_and_read (abfd, size, size);
+ e_data = _bfd_mmap_readonly_temporary (abfd, size, &e_data_addr,
+ &e_data_size);
if (e_data == NULL)
return NULL;
@@ -1936,7 +1946,7 @@ get_hash_table_data (bfd *abfd, bfd_size_type number,
while (number--)
i_data[number] = bfd_get_64 (abfd, e_data + number * ent_size);
- free (e_data);
+ _bfd_munmap_readonly_temporary (e_data_addr, e_data_size);
return i_data;
}
@@ -1985,6 +1995,10 @@ _bfd_elf_get_dynamic_symbols (bfd *abfd, Elf_Internal_Phdr *phdr,
size_t verneed_size = 0;
size_t extsym_size;
const struct elf_backend_data *bed;
+ void *dynbuf_addr = NULL;
+ void *esymbuf_addr = NULL;
+ size_t dynbuf_size = 0;
+ size_t esymbuf_size = 0;
/* Return TRUE if symbol table is bad. */
if (elf_bad_symtab (abfd))
@@ -2002,7 +2016,9 @@ _bfd_elf_get_dynamic_symbols (bfd *abfd, Elf_Internal_Phdr *phdr,
if (bfd_seek (abfd, phdr->p_offset, SEEK_SET) != 0)
goto error_return;
- dynbuf = _bfd_malloc_and_read (abfd, phdr->p_filesz, phdr->p_filesz);
+ dynbuf_size = phdr->p_filesz;
+ dynbuf = _bfd_mmap_readonly_temporary (abfd, dynbuf_size,
+ &dynbuf_addr, &dynbuf_size);
if (dynbuf == NULL)
goto error_return;
@@ -2080,11 +2096,17 @@ _bfd_elf_get_dynamic_symbols (bfd *abfd, Elf_Internal_Phdr *phdr,
goto error_return;
/* Dynamic string table must be valid until ABFD is closed. */
- strbuf = (char *) _bfd_alloc_and_read (abfd, dt_strsz + 1, dt_strsz);
+ strbuf = (char *) _bfd_mmap_readonly_persistent (abfd, dt_strsz);
if (strbuf == NULL)
goto error_return;
- /* Since this is a string table, make sure that it is terminated. */
- strbuf[dt_strsz] = 0;
+ if (strbuf[dt_strsz - 1] != 0)
+ {
+ /* It is an error if a string table is't terminated. */
+ _bfd_error_handler
+ /* xgettext:c-format */
+ (_("%pB: DT_STRTAB table is corrupt"), abfd);
+ goto error_return;
+ }
/* Get the real symbol count from DT_HASH or DT_GNU_HASH. Prefer
DT_HASH since it is simpler than DT_GNU_HASH. */
@@ -2259,7 +2281,10 @@ _bfd_elf_get_dynamic_symbols (bfd *abfd, Elf_Internal_Phdr *phdr,
if (filepos == (file_ptr) -1
|| bfd_seek (abfd, filepos, SEEK_SET) != 0)
goto error_return;
- esymbuf = _bfd_malloc_and_read (abfd, amt, amt);
+ esymbuf_size = amt;
+ esymbuf = _bfd_mmap_readonly_temporary (abfd, esymbuf_size,
+ &esymbuf_addr,
+ &esymbuf_size);
if (esymbuf == NULL)
goto error_return;
@@ -2303,7 +2328,7 @@ _bfd_elf_get_dynamic_symbols (bfd *abfd, Elf_Internal_Phdr *phdr,
goto error_return;
/* DT_VERSYM info must be valid until ABFD is closed. */
- versym = _bfd_alloc_and_read (abfd, amt, amt);
+ versym = _bfd_mmap_readonly_persistent (abfd, amt);
if (dt_verdef)
{
@@ -2315,8 +2340,7 @@ _bfd_elf_get_dynamic_symbols (bfd *abfd, Elf_Internal_Phdr *phdr,
goto error_return;
/* DT_VERDEF info must be valid until ABFD is closed. */
- verdef = _bfd_alloc_and_read (abfd, verdef_size,
- verdef_size);
+ verdef = _bfd_mmap_readonly_persistent (abfd, verdef_size);
}
if (dt_verneed)
@@ -2329,8 +2353,7 @@ _bfd_elf_get_dynamic_symbols (bfd *abfd, Elf_Internal_Phdr *phdr,
goto error_return;
/* DT_VERNEED info must be valid until ABFD is closed. */
- verneed = _bfd_alloc_and_read (abfd, verneed_size,
- verneed_size);
+ verneed = _bfd_mmap_readonly_persistent (abfd, verneed_size);
}
}
@@ -2353,8 +2376,8 @@ _bfd_elf_get_dynamic_symbols (bfd *abfd, Elf_Internal_Phdr *phdr,
/* Restore file position for elf_object_p. */
if (bfd_seek (abfd, saved_filepos, SEEK_SET) != 0)
res = false;
- free (dynbuf);
- free (esymbuf);
+ _bfd_munmap_readonly_temporary (dynbuf_addr, dynbuf_size);
+ _bfd_munmap_readonly_temporary (esymbuf_addr, esymbuf_size);
free (gnubuckets);
free (gnuchains);
free (mipsxlat);
@@ -9413,6 +9436,8 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
bfd_byte *contents = NULL;
unsigned int freeidx = 0;
size_t amt;
+ void *contents_addr = NULL;
+ size_t contents_size = 0;
if (elf_dynverref (abfd) != 0 || elf_tdata (abfd)->dt_verneed != NULL)
{
@@ -9449,7 +9474,10 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
if (bfd_seek (abfd, hdr->sh_offset, SEEK_SET) != 0)
goto error_return_verref;
- contents = _bfd_malloc_and_read (abfd, hdr->sh_size, hdr->sh_size);
+ contents_size = hdr->sh_size;
+ contents = _bfd_mmap_readonly_temporary (abfd, contents_size,
+ &contents_addr,
+ &contents_size);
if (contents == NULL)
goto error_return_verref;
@@ -9582,8 +9610,9 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
elf_tdata (abfd)->cverrefs = i;
if (contents != elf_tdata (abfd)->dt_verneed)
- free (contents);
+ _bfd_munmap_readonly_temporary (contents_addr, contents_size);
contents = NULL;
+ contents_addr = NULL;
}
if (elf_dynverdef (abfd) != 0 || elf_tdata (abfd)->dt_verdef != NULL)
@@ -9624,7 +9653,10 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
if (bfd_seek (abfd, hdr->sh_offset, SEEK_SET) != 0)
goto error_return_verdef;
- contents = _bfd_malloc_and_read (abfd, hdr->sh_size, hdr->sh_size);
+ contents_size = hdr->sh_size;
+ contents = _bfd_mmap_readonly_temporary (abfd, contents_size,
+ &contents_addr,
+ &contents_size);
if (contents == NULL)
goto error_return_verdef;
@@ -9778,8 +9810,9 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
}
if (contents != elf_tdata (abfd)->dt_verdef)
- free (contents);
+ _bfd_munmap_readonly_temporary (contents_addr, contents_size);
contents = NULL;
+ contents_addr = NULL;
}
else if (default_imported_symver)
{
@@ -9835,7 +9868,7 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
error_return:
if (contents != elf_tdata (abfd)->dt_verneed
&& contents != elf_tdata (abfd)->dt_verdef)
- free (contents);
+ _bfd_munmap_readonly_temporary (contents_addr, contents_size);
return false;
}
\f
diff --git a/bfd/elflink.c b/bfd/elflink.c
index e9cef470333..44709c9830c 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -549,22 +549,24 @@ bfd_elf_link_record_dynamic_symbol (struct bfd_link_info *info,
return false;
}
+ char *unversioned_name = NULL;
+
/* We don't put any version information in the dynamic string
table. */
name = h->root.root.string;
p = strchr (name, ELF_VER_CHR);
if (p != NULL)
- /* We know that the p points into writable memory. In fact,
- there are only a few symbols that have read-only names, being
- those like _GLOBAL_OFFSET_TABLE_ that are created specially
- by the backends. Most symbols will have names pointing into
- an ELF string table read from a file, or to objalloc memory. */
- *p = 0;
+ {
+ unversioned_name = bfd_malloc (p - name + 1);
+ memcpy (unversioned_name, name, p - name);
+ unversioned_name[p - name] = 0;
+ name = unversioned_name;
+ }
indx = _bfd_elf_strtab_add (dynstr, name, p != NULL);
if (p != NULL)
- *p = ELF_VER_CHR;
+ free (unversioned_name);
if (indx == (size_t) -1)
return false;
diff --git a/bfd/libbfd-in.h b/bfd/libbfd-in.h
index b8b2ce7ba09..c5a79cf932c 100644
--- a/bfd/libbfd-in.h
+++ b/bfd/libbfd-in.h
@@ -851,6 +851,10 @@ extern struct bfd_link_info *_bfd_get_link_info (bfd *)
extern bool _bfd_link_keep_memory (struct bfd_link_info *)
ATTRIBUTE_HIDDEN;
+extern uintptr_t _bfd_pagesize ATTRIBUTE_HIDDEN;
+extern uintptr_t _bfd_pagesize_m1 ATTRIBUTE_HIDDEN;
+extern uintptr_t _bfd_minimum_mmap_size ATTRIBUTE_HIDDEN;
+
#if GCC_VERSION >= 7000
#define _bfd_mul_overflow(a, b, res) __builtin_mul_overflow (a, b, res)
#else
@@ -888,6 +892,19 @@ _bfd_alloc_and_read (bfd *abfd, bfd_size_type asize, bfd_size_type rsize)
return NULL;
}
+#ifdef USE_MMAP
+extern void *_bfd_mmap_readonly_persistent
+ (bfd *, size_t) ATTRIBUTE_HIDDEN;
+extern void *_bfd_mmap_readonly_temporary
+ (bfd *, size_t, void **, size_t *) ATTRIBUTE_HIDDEN;
+extern void _bfd_munmap_readonly_temporary
+ (void *, size_t) ATTRIBUTE_HIDDEN;
+#else
+#define _bfd_mmap_readonly_persistent(abfd, rsize) \
+ _bfd_alloc_and_read (abfd, rsize, rsize)
+#define _bfd_munmap_readonly_temporary(ptr, rsize) free (ptr)
+#endif
+
static inline void *
_bfd_malloc_and_read (bfd *abfd, bfd_size_type asize, bfd_size_type rsize)
{
@@ -910,3 +927,15 @@ _bfd_malloc_and_read (bfd *abfd, bfd_size_type asize, bfd_size_type rsize)
}
return NULL;
}
+
+#ifndef USE_MMAP
+static inline void *
+_bfd_mmap_readonly_temporary (bfd *abfd, size_t rsize, void **map_addr,
+ size_t *map_size)
+{
+ void *mem = _bfd_malloc_and_read (abfd, rsize, rsize);
+ *map_addr = mem;
+ *map_size = rsize;
+ return mem;
+}
+#endif
diff --git a/bfd/libbfd.c b/bfd/libbfd.c
index f8d148c9677..a79c814a0dc 100644
--- a/bfd/libbfd.c
+++ b/bfd/libbfd.c
@@ -1038,6 +1038,141 @@ bfd_get_bits (const void *p, int bits, bool big_p)
return data;
}
\f
+#ifdef USE_MMAP
+/* Allocate a page to track mmapped memory and return the page and
+ the first entry. Return NULL if mmap fails. */
+
+static struct bfd_mmapped *
+bfd_allocate_mmapped_page (bfd *abfd, struct bfd_mmapped_entry **entry)
+{
+ struct bfd_mmapped * mmapped
+ = (struct bfd_mmapped *) mmap (NULL, _bfd_pagesize,
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS,
+ -1, 0);
+ if (mmapped == MAP_FAILED)
+ return NULL;
+
+ mmapped->next = abfd->mmapped;
+ mmapped->max_entry
+ = ((_bfd_pagesize - offsetof (struct bfd_mmapped, entries))
+ / sizeof (struct bfd_mmapped_entry));
+ mmapped->next_entry = 1;
+ abfd->mmapped = mmapped;
+ *entry = mmapped->entries;
+ return mmapped;
+}
+
+/* Mmap a memory region of RSIZE bytes with PROT at the current offset.
+ Return mmap address and size in MAP_ADDR and MAP_SIZE. Return NULL
+ on invalid input and MAP_FAILED for mmap failure. */
+
+static void *
+bfd_mmap_local (bfd *abfd, size_t rsize, int prot, void **map_addr,
+ size_t *map_size)
+{
+ if (!_bfd_constant_p (rsize))
+ {
+ ufile_ptr filesize = bfd_get_file_size (abfd);
+ if (filesize != 0 && rsize > filesize)
+ {
+ bfd_set_error (bfd_error_file_truncated);
+ return NULL;
+ }
+ }
+
+ void *mem;
+ ufile_ptr offset = bfd_tell (abfd);
+ mem = bfd_mmap (abfd, NULL, rsize, prot, MAP_PRIVATE, offset,
+ map_addr, map_size);
+ return mem;
+}
+
+/* Mmap a readonly memory region of RSIZE bytes at the current offset.
+ Return mmap address and size in MAP_ADDR and MAP_SIZE. Return NULL
+ on invalid input and MAP_FAILED for mmap failure. */
+
+void *
+_bfd_mmap_readonly_temporary (bfd *abfd, size_t rsize, void **map_addr,
+ size_t *map_size)
+{
+ /* Use mmap only if section size >= the minimum mmap section size. */
+ if (rsize < _bfd_minimum_mmap_size)
+ {
+ void *mem = _bfd_malloc_and_read (abfd, rsize, rsize);
+ /* NB: Set *MAP_ADDR to MEM and *MAP_SIZE to 0 to indicate that
+ _bfd_malloc_and_read is called. */
+ *map_addr = mem;
+ *map_size = 0;
+ return mem;
+ }
+
+ return bfd_mmap_local (abfd, rsize, PROT_READ, map_addr, map_size);
+}
+
+/* Munmap RSIZE bytes at PTR. */
+
+void
+_bfd_munmap_readonly_temporary (void *ptr, size_t rsize)
+{
+ /* NB: Since _bfd_munmap_readonly_temporary is called like free, PTR
+ may be NULL. Otherwise, PTR and RSIZE must be valid. If RSIZE is
+ 0, _bfd_malloc_and_read is called. */
+ if (ptr == NULL)
+ return;
+ if (rsize != 0)
+ {
+ if (munmap (ptr, rsize) != 0)
+ abort ();
+ }
+ else
+ free (ptr);
+}
+
+/* Mmap a readonly memory region of RSIZE bytes at the current offset.
+ Return NULL on invalid input or mmap failure. */
+
+void *
+_bfd_mmap_readonly_persistent (bfd *abfd, size_t rsize)
+{
+ /* Use mmap only if section size >= the minimum mmap section size. */
+ if (rsize < _bfd_minimum_mmap_size)
+ return _bfd_alloc_and_read (abfd, rsize, rsize);
+
+ void *mem, *map_addr;
+ size_t map_size;
+ mem = bfd_mmap_local (abfd, rsize, PROT_READ, &map_addr, &map_size);
+ if (mem == NULL)
+ return mem;
+ if (mem == MAP_FAILED)
+ return _bfd_alloc_and_read (abfd, rsize, rsize);
+
+ struct bfd_mmapped_entry *entry;
+ unsigned int next_entry;
+ struct bfd_mmapped *mmapped = abfd->mmapped;
+ if (mmapped != NULL
+ && (next_entry = mmapped->next_entry) < mmapped->max_entry)
+ {
+ entry = &mmapped->entries[next_entry];
+ mmapped->next_entry++;
+ }
+ else
+ {
+ mmapped = bfd_allocate_mmapped_page (abfd, &entry);
+ if (mmapped == NULL)
+ {
+ munmap (map_addr, map_size);
+ return NULL;
+ }
+ }
+
+ entry->addr = map_addr;
+ entry->size = map_size;
+
+ return mem;
+}
+#endif
+
/* Default implementation */
bool
@@ -1326,3 +1461,19 @@ _bfd_generic_init_private_section_data (bfd *ibfd ATTRIBUTE_UNUSED,
{
return true;
}
+
+uintptr_t _bfd_pagesize;
+uintptr_t _bfd_pagesize_m1;
+uintptr_t _bfd_minimum_mmap_size;
+
+__attribute__ ((unused, constructor))
+static void
+bfd_init_pagesize (void)
+{
+ _bfd_pagesize = getpagesize ();
+ if (_bfd_pagesize == 0)
+ abort ();
+ _bfd_pagesize_m1 = _bfd_pagesize - 1;
+ /* The minimum section size to use mmap. */
+ _bfd_minimum_mmap_size = _bfd_pagesize * 4;
+}
diff --git a/bfd/libbfd.h b/bfd/libbfd.h
index 7de23a50d18..0caf0f39e61 100644
--- a/bfd/libbfd.h
+++ b/bfd/libbfd.h
@@ -857,6 +857,10 @@ extern struct bfd_link_info *_bfd_get_link_info (bfd *)
extern bool _bfd_link_keep_memory (struct bfd_link_info *)
ATTRIBUTE_HIDDEN;
+extern uintptr_t _bfd_pagesize ATTRIBUTE_HIDDEN;
+extern uintptr_t _bfd_pagesize_m1 ATTRIBUTE_HIDDEN;
+extern uintptr_t _bfd_minimum_mmap_size ATTRIBUTE_HIDDEN;
+
#if GCC_VERSION >= 7000
#define _bfd_mul_overflow(a, b, res) __builtin_mul_overflow (a, b, res)
#else
@@ -894,6 +898,19 @@ _bfd_alloc_and_read (bfd *abfd, bfd_size_type asize, bfd_size_type rsize)
return NULL;
}
+#ifdef USE_MMAP
+extern void *_bfd_mmap_readonly_persistent
+ (bfd *, size_t) ATTRIBUTE_HIDDEN;
+extern void *_bfd_mmap_readonly_temporary
+ (bfd *, size_t, void **, size_t *) ATTRIBUTE_HIDDEN;
+extern void _bfd_munmap_readonly_temporary
+ (void *, size_t) ATTRIBUTE_HIDDEN;
+#else
+#define _bfd_mmap_readonly_persistent(abfd, rsize) \
+ _bfd_alloc_and_read (abfd, rsize, rsize)
+#define _bfd_munmap_readonly_temporary(ptr, rsize) free (ptr)
+#endif
+
static inline void *
_bfd_malloc_and_read (bfd *abfd, bfd_size_type asize, bfd_size_type rsize)
{
@@ -916,6 +933,18 @@ _bfd_malloc_and_read (bfd *abfd, bfd_size_type asize, bfd_size_type rsize)
}
return NULL;
}
+
+#ifndef USE_MMAP
+static inline void *
+_bfd_mmap_readonly_temporary (bfd *abfd, size_t rsize, void **map_addr,
+ size_t *map_size)
+{
+ void *mem = _bfd_malloc_and_read (abfd, rsize, rsize);
+ *map_addr = mem;
+ *map_size = rsize;
+ return mem;
+}
+#endif
/* Extracted from libbfd.c. */
void *bfd_malloc (bfd_size_type /*size*/) ATTRIBUTE_HIDDEN;
diff --git a/bfd/lynx-core.c b/bfd/lynx-core.c
index 44d94ad8745..9ec5a0d2028 100644
--- a/bfd/lynx-core.c
+++ b/bfd/lynx-core.c
@@ -96,7 +96,7 @@ lynx_core_file_p (bfd *abfd)
asection *newsect;
size_t amt;
- pagesize = getpagesize (); /* Serious cross-target issue here... This
+ pagesize = _bfd_pagesize; /* Serious cross-target issue here... This
really needs to come from a system-specific
header file. */
diff --git a/bfd/opncls.c b/bfd/opncls.c
index c764d204831..e6337b88e18 100644
--- a/bfd/opncls.c
+++ b/bfd/opncls.c
@@ -163,6 +163,18 @@ _bfd_new_bfd_contained_in (bfd *obfd)
static void
_bfd_delete_bfd (bfd *abfd)
{
+#ifdef USE_MMAP
+ struct bfd_mmapped *mmapped, *next;
+ for (mmapped = abfd->mmapped; mmapped != NULL; mmapped = next)
+ {
+ struct bfd_mmapped_entry *entries = mmapped->entries;
+ next = mmapped->next;
+ for (unsigned int i = 0; i < mmapped->next_entry; i++)
+ munmap (entries[i].addr, entries[i].size);
+ munmap (mmapped, _bfd_pagesize);
+ }
+#endif
+
/* Give the target _bfd_free_cached_info a chance to free memory. */
if (abfd->memory && abfd->xvec)
bfd_free_cached_info (abfd);
diff --git a/bfd/sysdep.h b/bfd/sysdep.h
index b907bc26a09..173f5804df3 100644
--- a/bfd/sysdep.h
+++ b/bfd/sysdep.h
@@ -98,6 +98,10 @@
#define MAP_FAILED ((void *) -1)
#endif
+#ifndef MAP_ANONYMOUS
+#define MAP_ANONYMOUS MAP_ANON
+#endif
+
#include "filenames.h"
#if !HAVE_DECL_FFS
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