Revert 'Workaround a hang in sigsuspend if compiled with Thread Sanitizer'

This reverts commit 04fd7b5309596423e4342502d3123028d836d551.

Because it does not avoid hangs in all cases when stopping the world.
A better solution is to re-enable signals in the suspend handler.

Allow to turn on spin locking even if thread-local allocations are used

* include/private/gc_locks.h [GC_PTHREADS && !GC_WIN32_THREADS
&& THREAD_LOCAL_ALLOC && !USE_PTHREAD_LOCKS] (UNCOND_LOCK,
UNCOND_UNLOCK): Use spin locks if USE_SPIN_LOCK is defined by client.

Eliminate TSan false positive for stop_info.stack_ptr

Without this patch, Thread Sanitizer reports a data race between
GC_has_other_debug_info() and the code which sets stop_info.stack_ptr.

* include/private/pthread_support.h (GC_Thread_Rep.status): Move the
field to be before stop_info one (so, the latter now has the offset
of at least 3 in words, while oh.oh_sz has the offset of 2 in words
(when KEEP_BACK_PTRS, MAKE_BACK_GRAPH and NEED_CALLINFO are not
defined)).

Eliminate TSan warning about data race when accessing GC_debugging_started

Now GC_debugging_started variable is double-checked with the allocation
lock held before calling GC_start_debugging_inner.

* dbg_mlc.c (GC_start_debugging_inner): Define as GC_INNER (instead of
STATIC).
* dbg_mlc.c [THREADS] (GC_start_debugging): Define as STATIC; do not
call GC_start_debugging_inner() if GC_debugging_started.
* dbg_mlc.c [!THREADS] (GC_start_debugging): Define as macro (redirect
to GC_start_debugging_inner).
* gcj_mlc.c (GC_debug_gcj_malloc): Call GC_start_debugging_inner
(holding the lock) instead of GC_start_debugging.
* include/private/gc_priv.h (GC_start_debugging): Rename to
GC_start_debugging_inner; improve usage comment.

Fix typo in a function name in README.sgi

* doc/README.sgi (4): Fix a typo ("pthread_cond_timedwait").

Workaround TSan false positives in extend_size_map

Thread Sanitizer reports data races between fill_size_map (called from
GC_extend_size_map) and GC_gcj_malloc[_ignore_off_page],
GC_malloc_kind_global, GC_generic_malloc_uncollectable,
GC_malloc_explicitly_typed_ignore_off_page which read a value from
GC_size_map before acquiring the allocation lock.  These races could
be ignored as the value is verified after acquiring the lock.

* alloc.c: Refine comment about GC_allocobj (and GC_size_map) usage
for the case of a multi-threaded environment.
* malloc.c (fill_size_map): New static function (with
GC_ATTR_NO_SANITIZE_THREAD attribute).
* malloc.c (GC_extend_size_map): Use fill_size_map() to fill in
a region of GC_size_map.

Remove GENERAL_MALLOC internal macro
(code refactoring)

* alloc.c: Update comment (about GC_allocobj usage).
* include/private/gc_priv.h (GENERAL_MALLOC): Remove.
* include/private/gc_priv.h (GENERAL_MALLOC_IOP): Move to typd_mlc.c.
* malloc.c (GC_malloc_kind_global): Expand GENERAL_MALLOC macro; copy
the comment from gc_priv.h.

Workaround a hang in sigsuspend if compiled with Thread Sanitizer

Issue #181 (bdwgc).

* pthread_stop_world.c [!GC_OPENBSD_UTHREADS && !NACL
&& THREAD_SANITIZER] (GC_suspend_handler_inner): Use sched_yield()
instead of sigsuspend(&suspend_handler_mask); add TODO item.

Workaround TSan false positives in suspend/resume_thread

* pthread_stop_world.c [!GC_OPENBSD_UTHREADS && !NACL
&& GC_ENABLE_SUSPEND_THREAD] (set_suspended_ext_flag): New static
function (with GC_ATTR_NO_SANITIZE_THREAD attribute); add comment.
* pthread_stop_world.c [!GC_OPENBSD_UTHREADS && !NACL
&& GC_ENABLE_SUSPEND_THREAD] (GC_suspend_thread): Call
set_suspended_ext_flag() instead of t->flags|=SUSPENDED_EXT.
* pthread_stop_world.c [!GC_OPENBSD_UTHREADS && !NACL
&& GC_ENABLE_SUSPEND_THREAD] (GC_resume_thread): Add
GC_ATTR_NO_SANITIZE_THREAD attribute; add comment.

Fix data race when getting object size in explicitly-typed allocators

* typd_mlc.c (COMPLEX): Reformat comment.
* typd_mlc.c (GC_malloc_explicitly_typed,
GC_malloc_explicitly_typed_ignore_off_page, GC_calloc_explicitly_typed):
Always use BYTES_TO_GRANULES(GC_size(op)) instead of GC_size_map[lb] to
determine size of the allocated object in granules (because the value
of GC_size_map[lb] might be updated by another thread since the value
use in GC_malloc_kind); add comment.

Remove 'ifdef USE_SPIN_LOCK' which is always false in gc_locks.h
(fix commit 9a20535)

* include/private/gc_locks.h [!GC_WIN32_THREADS && GC_PTHREADS
&& USE_PTHREAD_LOCKS && !GC_ASSERTIONS && NO_PTHREAD_TRYLOCK
&& USE_SPIN_LOCK] (UNCOND_LOCK): Define to
pthread_mutex_lock(&GC_allocate_ml) instead of GC_lock().

Workaround TSan false positive in write fault handler

The data races reported between GC_write_fault_handler,
catch_exception_raise and GC_install_header, GC_remove_header are OK
as the added or removed header should be already unprotected.

* os_dep.c [MPROTECT_VDB && THREADS] (is_header_found_async): New
static function (with GC_ATTR_NO_SANITIZE_THREAD attribute).
* os_dep.c [MPROTECT_VDB && !THREADS] (is_header_found_async): New
macro.
* os_dep.c [MPROTECT_VDB && !DARWIN] (GC_write_fault_handler): Use
is_header_found_async() instead of HDR(addr)!=0.
* os_dep.c [MPROTECT_VDB && DARWIN] (catch_exception_raise): Likewise.

Fix typo in 'gcdescr' documentation file

* doc/gcdescr.md (Allocation): Fix a typo ("the request is rounded").

Add basic calculation of the total full-collection time

Issue #139 (bdwgc).

New API functions: GC_start_performance_measurement,
GC_get_full_gc_total_time.

This patch is based on code originally written by Zoltan Somogyi
on 2008-03-18.

* alloc.c [!NO_CLOCK] (full_gc_total_time, measure_performance): New
static variable definition; add comment.
* alloc.c [!NO_CLOCK] (GC_start_performance_measurement,
GC_get_full_gc_total_time): New API function definition.
* alloc.c [!NO_CLOCK] (GC_try_to_collect_inner): Declare
start_time_valid local variable; set start_time_valid to true if
GET_TIME(start_time) is called; call GET_TIME(start_time) also if
measure_performance; declare time_diff local variable (used to store
the result of MS_TIME_DIFF());  GET_TIME(current_time) is called only
if start_time_valid; update full_gc_total_time if measure_performance.
* include/gc.h (GC_start_performance_measurement,
GC_get_full_gc_total_time): New API function declaration.
* tests/test.c (INIT_PERF_MEASUREMENT): New macro.
* tests/test.c (GC_COND_INIT): Call INIT_PERF_MEASUREMENT.
* tests/test.c [!NO_CLOCK] (check_heap_stats): Call
GC_get_full_gc_total_time() and print the total time of full
collections.

Fix double lock in a_set(f(a_get())) expression in gctest
(fix commit 8f5746e)

* tests/test.c [!AO_HAVE_store_release] (AO_store_release): Replace
macro with a static function definition (so, new_val argument is
evaluated before acquiring the lock).

Fix data race in a list referenced by A.aa (gctest)

* tests/test.c [!AO_HAVE_load] (AO_load): Remove macro.
* tests/test.c [!AO_HAVE_store] (AO_store): Likewise.
* tests/test.c [!AO_HAVE_load_acquire] (AO_load_acquire): New static
function (which uses FINALIZER_LOCK/FINALIZER_UNLOCK).
* tests/test.c [!AO_HAVE_store_release] (AO_store_release): New macro
(which uses FINALIZER_LOCK/FINALIZER_UNLOCK).
* tests/test.c [!AO_HAVE_fetch_and_add1] (AO_fetch_and_add1): Add
comment.
* tests/test.c (a_set): Use AO_store_release() instead of AO_store().
* tests/test.c (a_get): Use AO_load_acquire() instead of AO_load().
* tests/test.c (reverse_test_inner): Improve comment about thread
safety of a_set(reverse(reverse(a_get()))).

Avoid data race in finalized_count (gctest)

* tests/test.c (FINALIZER_LOCK, FINALIZER_UNLOCK): New macro.
* tests/test.c [GC_PTHREADS] (incr_lock): Move static variable out
of finalizer() and mktree() (use a single lock variable to access
finalized_count in finalizer, mktree and tree_test).
* tests/test.c (dropped_something): Change type back to int; remove
volatile.
* tests/test.c (finalizer, mktree): Use FINALIZER_[UN]LOCK() instead
of PCR_ThCrSec_Enter/ExitSys(), pthread_mutex_[un]lock(),
Enter/LeaveCriticalSection().
* tests/test.c (tree_test): Use FINALIZER_[UN]LOCK() to avoid data
race when accessing finalized_count and dropped_something; do not use
AO_load() and AO_store() to access dropped_something.
* tests/test.c

Eliminate TSan warning about A.dummy in gctest

* tests/test.c (reverse_test_inner): Move A.dummy=17 to
set_print_procs().
* tests/test.c (set_print_procs): Add comment.

Revert 'Eliminate TSan warnings (false positives) in gctest'

This reverts commit c7837f864970e3859a3b35b9b8c0858a3548a457.

Because it does not avoid potential data race between GC_malloc
(invoked from cons) and check_ints; the proper solution seems to
just use AO_load_acquire and AO_store_release to access A.aa.

Eliminate TSan warnings (false positives) in gctest

* tests/test.c (struct SEXPR): Declare first.
* tests/test.c (union sexpr_or_aot_u): New type.
* tests/test.c (struct SEXPR): Replace struct SEXPR* to sexpr_or_aot_u.
* tests/test.c (car, cdr, small_cons_uncollectable): Add .p suffix when
accessing sexpr_car and sexpr_cdr fields.
* tests/test.c [GC_GCJ_SUPPORT] (fake_gcj_mark_proc, gcj_cons):
Likewise.
* tests/test.c  [!VERY_SMALL_CONFIG] (small_cons): Likewise.
* tests/test.c (atomic_car, atomic_cdr): New macro; add comment.
* tests/test.c [!VERY_SMALL_CONFIG] (cons): Store atomic_car and
atomic_cdr atomically.
* tests/test.c [VERY_SMALL_CONFIG] (small_cons): Likewise.
* tests/test.c [!VERY_SMALL_CONFIG] (cons): Ignore store random value
at *p if p points inside r->sexpr_car/cdr; add comment.
* tests/test.c (reverse1, check_ints): Use atomic_car() and
atomic_cdr() instead of car() and cdr(), respectively.
* tests/test.c (reverse_test_inner): Move A.dummy=17 to
set_print_procs().
* tests/test.c (set_print_procs): Add comment.

Workaround TSan false positives in mark_from, push_*_eager

* mark.c (GC_mark_from, GC_push_all_eager): Annotate with
GC_ATTR_NO_SANITIZE_THREAD.
* mark.c [WRAP_MARK_SOME && PARALLEL_MARK] (GC_push_conditional_eager):
Likewise.

Workaround TSan false positive in [set_]mark_bit_from_hdr

There is no data race between GC_set_fl_marks and GC_is_marked because
bit_no is different.

* include/private/gc_priv.h [THREADS && THREAD_SANITIZER]: Include
gc_atomic_ops.h.
* include/private/gc_priv.h [!USE_MARK_BYTES && THREAD_SANITIZER
&& THREADS] (OR_WORD): Use AO_or; update comment.

Workaround TSan false positive in invoke_finalizers

* finalize.c [THREADS && !THREAD_SANITIZER] (GC_invoke_finalizers): Do
not compare bytes_freed_before to GC_bytes_freed without the lock; add
comment.
* include/private/gc_priv.h (_GC_arrays._finalizer_bytes_freed): Replace
"mem." to "memory" in a comment.

Print time passed since GC initialization in GC_dump

Issue #139 (bdwgc).

* misc.c [!NO_DEBUGGING && !NO_CLOCK] (GC_init_time): New static
variable.
* misc.c [!NO_DEBUGGING && !NO_CLOCK] (GC_init): Set GC_init_time.
* misc.c [!NO_DEBUGGING && !NO_CLOCK] (GC_dump_named): Define
current_time local variable; print the time since GC initialization
(in milliseconds); add comment.

Update ChangeLog file

Update ChangeLog file (v7.6 changes only)

Update ChangeLog file (v7.4 changes only)

Do not use system clock consistently if NO_CLOCK

Issue #139 (bdwgc).

* alloc.c (GC_try_to_collect_inner, world_stopped_total_time,
world_stopped_total_divisor, MAX_TOTAL_TIME_DIVISOR, GC_stopped_mark):
Replace "ifndef SMALL_CONFIG" with "ifndef NO_CLOCK".
* reclaim.c (GC_reclaim_all): Likewise.
* alloc.c (GC_finish_collection): Replace "ifndef SMALL_CONFIG" with
"ifndef NO_CLOCK" except for GC_print_finalization_stats invocation.
* doc/README.macros (NO_CLOCK): Document.
* include/private/gc_priv.h (CLOCK_TYPE, GET_TIME, MS_TIME_DIFF): Do
not define if NO_CLOCK.
* include/private/gc_priv.h (GC_print_stats): Define as a macro (to 0)
only if both NO_CLOCK and SMALL_CONFIG are defined.
* misc.c (GC_print_stats): Do not define if both NO_CLOCK and
SMALL_CONFIG are defined.
* misc.c (GC_init): Do not set GC_print_stats only if both NO_CLOCK
and SMALL_CONFIG are defined.
* tests/test.c (run_one_test): Do not define start_time, reverse_time,
time_diff local variables (and do not use GET_TIME, MS_TIME_DIFF) if
NO_CLOCK is defined.

Travis CI: Test NO_CLOCK

Make extend_size_map() static
(code refactoring)

* include/private/gc_priv.h (GC_extend_size_map): Remove prototype.
* malloc.c (GC_extend_size_map): Move the function definition from
misc.c; change GC_INNER to STATIC; reformat code; remove j and
much_smaller_than_i local variables; add assertions that I_HOLD_LOCK
and GC_size_map[i]==0; remove comment that GC_size_map[i] is expected
to be zero.
* malloc.c (GC_generic_malloc_inner): Capitalize the first letter of
the description comment.
* misc.c (GC_extend_size_map): Remove the definition.

Fix typos in documentation (for extend_size_map and ews4800)

* doc/README.ews4800: Fix typos ("32-bit", "64-bit").
* misc.c (GC_extend_size_map): Fix typo ("16-byte") in a comment.

Add two-argument alloc_size attribute to calloc_explicitly_typed (GCC)

* include/gc_config_macros.h [!GC_ATTR_CALLOC_SIZE]
(GC_ATTR_CALLOC_SIZE): New macro (which uses alloc_size attribute
if GCC or Clang).
* include/gc_typed.h (GC_calloc_explicitly_typed): Add
GC_ATTR_CALLOC_SIZE(1,2) attribute.

Use __declspec(allocator) for malloc-like prototypes (MS VS 2015+)

* include/gc_config_macros.h [_MSC_VER>=1900 && !__EDG__]
(GC_ATTR_MALLOC): Add __declspec(allocator).

Revert 'Never try to include private/config.h'

This reverts commit 6abcbd9101a17443a848e58f6bad45d0b0aa4d1a.

Because "config.h" file may be located in some folder other than the
parent of "private" folder, e.g. during "make distcheck".

Workaround Thread Sanitizer (TSan) false positive warnings (partially)

This patch covers only data race false positive warnings reported in
async_set_pht_entry_from_index, GC_clear_stack, GC_invoke_finalizers,
GC_lock, GC_noop1, GC_notify_or_invoke_finalizers, GC_pthread_create,
GC_suspend_handler_inner, I_DONT_HOLD_LOCK.

* finalize.c (GC_should_invoke_finalizers): Add
GC_ATTR_NO_SANITIZE_THREAD.
* mark.c (GC_noop1): Likewise.
* os_dep.c [MPROTECT_VDB && THREADS && AO_HAVE_test_and_set_acquire]
(async_set_pht_entry_from_index): Likewise.
* finalize.c (GC_invoke_finalizers, GC_notify_or_invoke_finalizers):
Call GC_should_invoke_finalizers() instead of
GC_fnlz_roots.finalize_now!=NULL.
* include/private/gc_locks.h [(GC_WIN32_THREADS && !USE_PTHREAD_LOCKS
|| GC_PTHREADS) && GC_ASSERTIONS && THREAD_SANITIZER]
(I_DONT_HOLD_LOCK): Define to TRUE; add comment.
* include/private/gc_locks.h [!GC_ALWAYS_MULTITHREADED
&& THREAD_SANITIZER] (set_need_to_lock): Do not set GC_need_to_lock if
already set; add comment.
* include/private/gc_priv.h [!GC_ATTR_NO_SANITIZE_THREAD]
(GC_ATTR_NO_SANITIZE_THREAD): New macro.
* include/private/gcconfig.h [__has_feature &&
__has_feature(thread_sanitizer)] (THREAD_SANITIZER): Define.
* misc.c [THREADS] (next_random_no): New static function (with
GC_ATTR_NO_SANITIZE_THREAD).
* pthread_stop_world.c [!GC_OPENBSD_UTHREADS && !NACL]
(update_last_stop_count): Likewise.
* pthread_support.c [THREAD_SANITIZER && (USE_SPIN_LOCK
|| !NO_PTHREAD_TRYLOCK)] (is_collecting): Likewise.
* pthread_support.c [USE_SPIN_LOCK] (set_last_spins_and_high_spin_max,
reset_spin_max): Likewise.
* misc.c [THREADS] (GC_clear_stack): Remove random_no static variable;
use next_random_no() instead of ++random_no%13.
* pthread_stop_world.c [!GC_OPENBSD_UTHREADS && !NACL]
(GC_suspend_handler_inner): Call update_last_stop_count() instead of
me->stop_info.last_stop_count=my_stop_count.
* pthread_support.c [USE_SPIN_LOCK || !NO_PTHREAD_TRYLOCK] (SPIN_MAX):
Define only if not yet.
* pthread_support.c [USE_SPIN_LOCK || !NO_PTHREAD_TRYLOCK]
(GC_collecting): Initialize to FALSE instead of 0.
* pthread_support.c [!(THREAD_SANITIZER && (USE_SPIN_LOCK
|| !NO_PTHREAD_TRYLOCK))] (is_collecting): Define as a macro.
* pthread_support.c [USE_SPIN_LOCK] (low_spin_max, high_spin_max,
spin_max, last_spins): Move definition out of GC_lock().
* pthread_support.c (GC_lock): Use is_collecting(),
set_last_spins_and_high_spin_max() and reset_spin_max().

Refine should_invoke_finalizers documentation

* include/gc.h (GC_should_invoke_finalizers): Add comment that it is
not synchronized.

Never try to include private/config.h

config.h is now located in "include" folder (not "include/private").

* include/private/gc_pmark.h [HAVE_CONFIG_H && !GC_PRIVATE_H]
(include config.h): Add "../" prefix.
* include/private/gc_priv.h [HAVE_CONFIG_H] (include config.h):
Likewise.

.gitignore: Do not ignore include/private/config.h

config.h was moved to "include" folder in gc-7.4.0.

Update AUTHORS file (add Erik M. Bray)

Use mprotect instead of mmap in GC_unmap() on Cygwin

Issue #187 (BDWGC).

* configure.ac [$enable_munmap!="" && $enable_munmap!=no]
(USE_WINALLOC): Replace AC_DEFINE with AH_TEMPLATE; remove comment
about a workaround for Cygwin; remove "if $host=*-*-cygwin*".
* os_dep.c [CYGWIN32 && USE_MUNMAP] (GC_setpagesize): Set GC_page_size
to dwAllocationGranularity (instead of dwPageSize); add comment; add
assertion that dwAllocationGranularity is not less than dwPageSize.
* os_dep.c [USE_MUNMAP && CYGWIN32 && !USE_WINALLOC] (GC_unmap,
GC_unmap_gap): Call mprotect() instead of mmap(); add comment.

Fix 'package requirements (atomic_ops) were not met' configure error
(fix commit 3d34335)

* configure.ac [$missing_libatomic_ops] (PKG_CHECK_MODULES):
Pass no-op to action-if-not-found parameter (because the default
action-if-not-found ends the execution with an error in case of the
missing dependency).

Allow PKG_CHECK_MODULES in configure.ac to be commented out easily
(code refactoring)

* configure.ac [$with_libatomic_ops!=no && $with_libatomic_ops!=none]
(missing_libatomic_ops): Set to true (before PKG_CHECK_MODULES).
* configure.ac [$missing_libatomic_ops] (PKG_CHECK_MODULES): Set
missing_libatomic_ops back to false if atomic_ops module is not found;
add comment (about pkg-config and the possibility to comment out
PKG_CHECK_MODULES).

New API function (GC_is_init_called) to check if BDWGC is initialized

Issue #186 (bdwgc).

* include/gc.h (GC_is_init_called): New API function declaration.
* misc.c (GC_is_init_called): New API function definition.
* tests/test.c (check_heap_stats): Add a test that GC is initialized.

Test GC initialization from non-main thread on FreeBSD and NetBSD

Issue #180 (bdwgc).

* tests/initsecondarythread.c [(FREEBSD || LINUX || NETBSD)
&& !NO_PTHREAD_GETATTR_NP && !NO_PTHREAD_ATTR_GET_NP] (main): Do not
call GC_INIT().

Update ChangeLog file

Update ChangeLog file (v7.6 changes only)

Update ChangeLog file (v7.2 - v7.4 changes only)

Support GC_init (and get_stack_base) from non-main thread on NetBSD

Now GC_get_[main_]stack_base uses pthread_getattr_np() and
pthread_attr_getstack() to determine the stack base address on NetBSD.

* include/private/gcconfig.h [NETBSD && !NO_PTHREAD_GETATTR_NP]
(HAVE_PTHREAD_GETATTR_NP): Define.

Eliminate TSan warnings for all counters and A.aa variable (gctest)

Now most of the counters in gctest are updated using atomic increment.
And, the values of gctest dropped_something and A.aa variables are
updated and fetch using the atomic primitives.

* tests/test.c [!AO_CLEAR] (AO_t): Define.
* tests/test.c [!AO_HAVE_load] (AO_load): Define (as a non-atomic
operation).
* tests/test.c [!AO_HAVE_store] (AO_store): Likewise.
* tests/test.c [!AO_HAVE_fetch_and_add1] (AO_fetch_and_add1): Likewise.
* tests/test.c (stubborn_count, uncollectable_count,
collectable_count, atomic_count, realloc_count): Change type from int
to AO_t; add volatile qualifier; update comment; remove FIXME.
* tests/test.c (extra_count): Define unconditionally; change type from
int to AO_t; add volatile qualifier; update comment.
* tests/test.c [!VERY_SMALL_CONFIG] (cons): Use AO_fetch_and_add1 to
get and update the values of extra_count and stubborn_count.
* tests/test.c (small_cons_uncollectable): Use AO_fetch_and_add1 to
update the value of uncollectable_count.
* tests/test.c [!DBG_HDRS_ALL] (run_one_test): Likewise.
* tests/test.c [GC_GCJ_SUPPORT] (gcj_cons): Remove obj_cnt static
variable; use extra_count instead of obj_cnt; use AO_fetch_and_add1 to
get and update the value of extra_count.
* tests/test.c (A): Add volatile qualifier; change the type of aa
field from sexpr to AO_t.
* tests/test.c (a): Do not define (and undefine).
* tests/test.c (a_set, a_get): New macro (that uses AO_store/load).
* tests/test.c (reverse_test_inner): Use a_set() and a_get() to store
and fetch the value of a, respectively; use AO_fetch_and_add1 to
update the value of realloc_count.
* tests/test.c (dropped_something): Change type from int to AO_t.
* tests/test.c (counter): Remove.
* tests/test.c (mktree): Use extra_count instead of counter; use
AO_fetch_and_add1 to update the value of extra_count.
* tests/test.c [GC_PTHREADS && !SMALL_CONFIG && !GC_DEBUG]
(alloc8bytes): Use AO_fetch_and_add1 to update the value of
uncollectable_count.
* tests/test.c (alloc_small, run_one_test): Use AO_fetch_and_add1 to
update the value of atomic_count.
* tests/test.c (tree_test): Use AO_load and AO_store to get and set
the value of dropped_something, respectively.
* tests/test.c (check_heap_stats): Cast uncollectable_count,
atomic_count, stubborn_count, realloc_count to int in printf() call.

Print realloc_count in gctest

Without this patch, realloc_count value is never used.

* tests/test.c (check_heap_stats): Print realloc_count value (after
printing other count variables).

Fix missing atomic_count and realloc_count incrementation in gctest

* tests/test.c [!AT_END && !THREADS] (reverse_test_inner): Increment
realloc_count after GC_REALLOC() call.
* tests/test.c (run_one_test): Increment atomic_count after
(void)GC_MALLOC_ATOMIC(0) and GC_malloc_atomic(1) calls.

Travis CI: Pass --disable-shared option to OS X build with ASan
(fix commit 535cf36)

Fix 'pthread_np.h: no such file' compiler error on kFreeBSD
(fix commit 49d7fe7)

Issue #180 (bdwgc).

* include/private/gcconfig.h [(FREEBSD && __GLIBC__ || LINUX
|| PLATFORM_ANDROID) && !NO_PTHREAD_GETATTR_NP]
(HAVE_PTHREAD_GETATTR_NP): New macro.
* include/private/gcconfig.h [FREEBSD && !__GLIBC__
&& !NO_PTHREAD_ATTR_GET_NP] (HAVE_PTHREAD_NP_H,
HAVE_PTHREAD_ATTR_GET_NP): Likewise.
* os_dep.c [!BEOS && !AMIGA && !OS2 && !MSWIN32 && !MSWINCE
&& !CYGWIN32 && !GC_OPENBSD_THREADS] (include pthread.h,
include pthread_np.h, GC_get_main_stack_base): Check presence of
HAVE_PTHREAD_ATTR_GET_NP, HAVE_PTHREAD_GETATTR_NP, HAVE_PTHREAD_NP_H
macros instead of FREEBSD, NO_PTHREAD_ATTR_GET_NP, LINUX,
PLATFORM_ANDROID, NO_PTHREAD_GETATTR_NP.
* os_dep.c [!HAVE_GET_STACK_BASE] (GC_get_stack_base): Check presence
of THREADS, HAVE_PTHREAD_ATTR_GET_NP, HAVE_PTHREAD_GETATTR_NP,
HAVE_PTHREAD_NP_H macros instead of GC_FREEBSD_THREADS,
NO_PTHREAD_ATTR_GET_NP, GC_LINUX_THREADS, PLATFORM_ANDROID,
NO_PTHREAD_GETATTR_NP, FREEBSD.

Travis CI: Test also 32-bit build with ASan (on OS X, with unmapping)

Travis CI: Test also with Leak Sanitizer (LSan)

Move conditional GC_need_to_lock setting to gc_locks.h
(code refactoring)

* include/private/gc_locks.h [GC_PTHREADS && !THREAD_LOCAL_ALLOC
&& !USE_PTHREAD_LOCKS && !GC_ASSERTIONS] (UNCOND_LOCK): Remove
GC_ASSERT(I_DONT_HOLD_LOCK()) because it is no-op (when assertion
checking is off).
* include/private/gc_locks.h [THREADS] (set_need_to_lock): New macro.
* pthread_support.c [!GC_ALWAYS_MULTITHREADED]
(GC_allow_register_threads, WRAP_FUNC(pthread_create)): Replace
GC_need_to_lock=TRUE to set_need_to_lock().
* win32_threads.c [!GC_ALWAYS_MULTITHREADED]
(GC_allow_register_threads, GC_CreateThread, GC_init_parallel):
Likewise.
* win32_threads.c [!MSWINCE && !CYGWIN32 && !GC_ALWAYS_MULTITHREADED]
(GC_beginthreadex): Likewise.
* win32_threads.c [GC_PTHREADS && !GC_ALWAYS_MULTITHREADED]
(GC_pthread_create): Likewise.

Eliminate TSan warnings for print_proc variables assignment (gctest)

Now GC_is_valid_displacement_print_proc and GC_is_visible_print_proc
are set only once (before the first invocation of run_one_test).

* tests/test.c [DBG_HDRS_ALL] (set_print_procs): New macro (defined
to (void)0).
* tests/test.c [!DBG_HDRS_ALL] (set_print_procs): New function (which
sets GC_is_valid_displacement_print_proc and GC_is_visible_print_proc).
* tests/test.c (fail_count, fail_proc1, TEST_FAIL_COUNT): Do not
define if DBG_HDRS_ALL.
* tests/test.c [!DBG_HDRS_ALL] (run_one_test): Do not set
GC_is_valid_displacement_print_proc and GC_is_visible_print_proc.
* tests/test.c (main): Call set_print_procs() before run_one_test().
* tests/test.c [PCR] (test): Likewise.

Support GC_init (and get_stack_base) from non-main thread on FreeBSD

Issue #180 (bdwgc).

Now GC_get_[main_]stack_base uses pthread_attr_get_np() and
pthread_attr_getstack() to determine the stack base address.

* os_dep.c [FREEBSD && !NO_PTHREAD_ATTR_GET_NP && (THREADS
|| USE_GET_STACKBASE_FOR_MAIN)]: Include pthread.h and pthread_np.h.
* os_dep.c [FREEBSD && !NO_PTHREAD_ATTR_GET_NP
&& (USE_GET_STACKBASE_FOR_MAIN || THREADS && !REDIRECT_MALLOC)]
(GC_get_main_stack_base): Call pthread_attr_init, pthread_attr_get_np
and pthread_attr_getstack to determine the stack base address of the
current thread (fall back to GC_freebsd_main_stack_base in case of
failure).
* os_dep.c [(GC_FREEBSD_THREADS && !NO_PTHREAD_ATTR_GET_NP]
(GC_get_stack_base): Call pthread_attr_init, pthread_attr_get_np and
pthread_attr_getstack to determine the stack base address of the
current thread.

Fix data race in collectable_count (gctest)

* tests/test.c [THREADS && (GC_BUILTIN_ATOMIC || PARALLEL_MARK
|| !GC_WIN32_THREADS)]: Include gc_atomic_ops.h.
* tests/test.c [AO_HAVE_fetch_and_add1] (collectable_count): Change
type to volatile AO_t (and make it static to initalize it without "=0").
* tests/test.c [!AO_HAVE_fetch_and_add1] (AO_fetch_and_add1): Define
to a non-atomic increment (for a single-threaded build).
* tests/test.c (small_cons, reverse_test_inner, mktree, chktree,
alloc8bytes, typed_test, run_one_test): Use
AO_fetch_and_add1(&collectable_count) instead of collectable_count++.
* tests/test.c (check_heap_stats): Cast collectable_count to int in
GC_printf() call.

Fix missing [un]collectable_count increments in gctest

* tests/test.c [!DBG_HDRS_ALL] (run_one_test): Increment
uncollectable_count instead of collectable_count (for
GC_malloc_uncollectable(0)).
* tests/test.c [!DBG_HDRS_ALL] (run_one_test): Add missing increments
of collectable_count for GC_malloc(8) and GC_malloc(17).
* tests/test.c (run_one_test): Add missing increment of
collectable_count for (void)GC_MALLOC(0).

Eliminate '-pedantic is not option that controls warnings' GCC-6.4 message
(fix commits 84c0313, 04eb273)

* mark.c [WRAP_MARK_SOME && (MSWIN32 || MSWINCE) && __GNUC__]
(GC_mark_some): Use "-Wpedantic" instead of "-pedantic" (in pragma
GCC diagnostic) if GCC v6.4+.

Eliminate 'non-null arg compared to null' warning in toggleref_add (GCC)
(fix commit 86991cb)

* finalize.c [!GC_TOGGLE_REFS_NOT_NEEDED] (GC_toggleref_add): Use
NONNULL_ARG_NOT_NULL to check pointer argument marked as non-null (in
the function declaration) is actually non-null.

Fix pthread_detach for threads not yet registered (Cygwin, winpthreads)

* win32_threads.c [GC_PTHREADS] (GC_pthread_detach): Repeat
GC_lookup_pthread() (with a 10 msec delay) while t is null; add comment
and TODO; remove ABORT if t is null (as t is never null after
pthread_detach call).

Fix get_maps on proc maps file asynchronous growth

Issue #179 (bdwgc).

Asynchronous growth of /proc/self/maps could be caused by some thread
which is not currently registered (e.g. stack allocation on thread
creation or a non-GC heap allocation from an unregistered thread).

* os_dep.c [NEED_PROC_MAPS] (GC_get_maps): Refine comment.
* os_dep.c [NEED_PROC_MAPS && THREADS] (GC_get_maps): Replace ABORT
with WARN call; refine printed message; add comment.

Fix pthread_join when thread is registered in thread key destructor

* pthread_support.c (WRAP_FUNC(pthread_join)): Remove assertion that
thread is finished; call GC_delete_gc_thread only if thread is
finished; add comment.
* win32_threads.c [GC_PTHREADS] (GC_pthread_join): Call
GC_delete_gc_thread_no_free and GC_INTERNAL_FREE only if thread is
finished.

Fix pthread_join to avoid thread removal on failure (Cygwin, winpthreads)

* win32_threads.c [GC_WIN32_PTHREADS] (GC_pthread_join): Do not call
GC_lookup_pthread if pthread_join failed.
* win32_threads.c [GC_PTHREADS] (GC_pthread_join): Do not call
GC_delete_gc_thread_no_free, GC_INTERNAL_FREE if pthread_join failed.
* win32_threads.c [GC_PTHREADS && DEBUG_THREADS] (GC_pthread_join):
Log whether pthread_join succeeded or failed.

Fix removal of dead threads in a child process

GC_threads table may contain several elements with the same pthread id,
so GC_remove_all_threads_but_me should remove all elements except for
the first found element matching the id of the current thread.

* pthread_support.c [CAN_HANDLE_FORK] (GC_remove_all_threads_but_me):
Do not assign me if it is already non-null; add comment.
* win32_threads.c [CAN_HANDLE_FORK] (GC_remove_all_threads_but_me):
Likewise.
* win32_threads.c [CAN_HANDLE_FORK] (GC_remove_all_threads_but_me):
Remove GC_ASSERT(me==NULL).

Fix double lock in pthread_detach (Cygwin, winpthreads)

* win32_threads.c [GC_PTHREADS] (GC_pthread_detach): Do not hold the
allocation lock when GC_lookup_pthread is invoked.

Do not disable parallel mark for WRAP_MARK_SOME

Issue #179 (bdwgc).

Now, if there is a chance of unmapping of root segments, the latter
ones are scanned immediately by GC_push_roots thus preventing memory
protection faults in GC_mark_local.

* include/private/gc_priv.h (GC_PUSH_CONDITIONAL): Move definition to
mark_rts.c.
* include/private/gcconfig.h [WRAP_MARK_SOME && PARALLEL_MARK]
(PARALLEL_MARK): Do not undefine; remove TODO item.
* mark.c [WRAP_MARK_SOME && PARALLEL_MARK] (GC_push_conditional_eager):
New internal function; add TODO item.
* mark_rts.c [WRAP_MARK_SOME && PARALLEL_MARK]
(GC_push_conditional_eager): Declare function.
* mark_rts.c [WRAP_MARK_SOME && PARALLEL_MARK] (GC_PUSH_CONDITIONAL):
Define to GC_push_conditional_eager if GC_parallel.

Align local_mark_stack in help_marker explicitly

* mark.c [PARALLEL_MARK] (GC_help_marker): Declare my_id_mse local
variable (of mse type) instead of unsigned my_id; define my_id as
macro to my_id_mse.mse_descr.w; cast my_id to unsigned or int in
GC_helper_count assignment and GC_mark_local() call.

Fix thread id leaks in subthread_create and threadkey_test

* tests/subthread_create.c [GC_PTHREADS] (entry): Call pthread_detach
for the created thread.
* tests/threadkey_test.c (main): Likewise.
* tests/test.c [GC_PTHREADS && CPPCHECK] (main): Remove
UNTESTED(GC_pthread_detach).
* tests/threadkey_test.c (on_thread_exit_inner): New local variable
attr; call pthread_attr_init and pthread_attr_setdetachstate;
pass attr to GC_pthread_create; call pthread_attr_destroy.

Fix missing new-line at format strings end in subthread_create test

* tests/subthread_create.c [GC_PTHREADS] (entry, main): Append "\n" to
fprintf() format string (where missing).

Fix infinite mark_some calls after memory mapping disappeared (Glibc)

Issue #179 (bdwgc).

* mark.c [WRAP_MARK_SOME && REGISTER_LIBRARIES_EARLY] (GC_mark_some):
Call GC_cond_register_dynamic_libraries (with the world running)
before GC_invalidate_mark_state().

Fix 'undefined reference to GC_wait_for_reclaim' linker error
(fix commit f4d690e)

Issue #179 (bdwgc).

* include/private/gc_pmark.h [HAVE_CONFIG_H]: Do not include config.h
if already included from gc_priv.h (to avoid PARALLEL_MARK macro
redefinition in config.h after it was undefined in gcconfig.h).

Add TODO item to suppress 'called on pointer without debugging info'

* dbg_mlc.c [REDIRECT_FREE && USE_PROC_FOR_LIBRARIES] (GC_debug_free):
Add TODO item not to call GC_err_printf() when free() is called from
libpthread or libdl.

Eliminate 'boolean result used in bitwise op' cppcheck false warning

* extra/AmigaOS.c [GC_AMIGA_DS] (GC_register_data_segments):
Replace (ULONG)&data[1] in comparison to (ULONG)(&data[1]).
* misc.c [!THREADS && !SPARC] (GC_do_blocking_inner):
Replace (ptr_t)&d in comparison to (ptr_t)(&d).

Fix USE_GET_STACKBASE_FOR_MAIN definition in gcconfig.h

* include/private/gcconfig.h [PLATFORM_ANDROID && !THREADS]
(USE_GET_STACKBASE_FOR_MAIN): Move definition down to be after THREADS
definition.

Allow custom N_LOCAL_ITERS and ENTRIES_TO_GET values

* mark.c [PARALLEL_MARK] (N_LOCAL_ITERS): Do not define if already
defined.
* mark.c [PARALLEL_MARK] (ENTRIES_TO_GET): Likewise.

Fix missing started_thread_while_stopped call from  mark_some if GCC/Clang

* mark.c [WRAP_MARK_SOME && GC_WIN32_THREADS && !GC_PTHREADS]
(GC_started_thread_while_stopped): Declare even if __GNUC__.
* mark.c [WRAP_MARK_SOME && GC_WIN32_THREADS && (MSWIN32 || MSWINCE)]
(GC_mark_some): Invoke GC_started_thread_while_stopped (unless
GC_PTHREADS).
* win32_threads.c [WRAP_MARK_SOME && !GC_PTHREADS]
(GC_started_thread_while_stopped): Define even if __GNUC__.

Fix SIGSEGV in mark_from called from do_local_mark if WRAP_MARK_SOME

Issue #179 (bdwgc).

Parallel marker is disabled (for now) if there is a chance of
scanning unmapped data roots (because GC_do_local_mark is not
prepared to deal with memory protection faults gracefully).

* mark.c [MSWIN32 || USE_PROC_FOR_LIBRARIES] (WRAP_MARK_SOME): Move
definition to gcconfig.h.
* include/private/gcconfig.h [WRAP_MARK_SOME && PARALLEL_MARK]
(PARALLEL_MARK): Undefine (as not implemented yet).

Fix typo in 'scale' documentation file

* doc/scale.md (Options for enhanced scalability): Fix a typo
("be replaced").

Remove unnecessary type casts of printf arguments to unsigned long
(code refactoring)

* alloc.c [!NO_DEBUGGING] (GC_print_heap_sects): Remove unnecessary
cast to unsigned long in GC_*_printf call and adjust printf format
specifier to match the argument type.
* checksums.c [CHECKSUMS] (GC_checksum): Likewise.
* mark.c [PARALLEL_MARK] (GC_mark_local): Likewise.
* tests/test.c (typed_test): Likewise.
* checksums.c [CHECKSUMS] (GC_checksum): Change type of GC_n_clean,
GC_n_dirty from int to unsigned long.

Fix printf arguments type in print_callers

* os_dep.c [NEED_CALLINFO] (GC_print_callers): Cast info[i].ci_pc to
unsigned long in GC_err_printf call to match the format specifier.

Fix assertion violation in return_single_freelist in child process

Issue #171 (bdwgc).

GC_destroy_thread_local cannot be called from a thread other than
the current one.

* pthread_support.c [CAN_HANDLE_FORK && THREAD_LOCAL_ALLOC]
(GC_remove_all_threads_but_me): Do not call GC_destroy_thread_local;
add comment.
* win32_threads.c [CAN_HANDLE_FORK && THREAD_LOCAL_ALLOC]
(GC_remove_all_threads_but_me): Likewise.
* thread_local_alloc.c [THREAD_LOCAL_ALLOC] (GC_destroy_thread_local):
Update comment.

Travis CI: Test USE_CUSTOM_SPECIFIC

Fix GC_remove_specific invocation from remove_all_threads_but_me
(fix commits fcfae7f, 38e65ea)

* include/private/specific.h (GC_remove_specific): Define as macro
(calls GC_remove_specific_after_fork).
* include/private/specific.h (GC_remove_specific_after_fork): New
GC_INNER function declaration.
* include/private/thread_local_alloc.h [USE_PTHREAD_SPECIFIC
|| USE_COMPILER_TLS || USE_WIN32_COMPILER_TLS || USE_WIN32_SPECIFIC]
(GC_remove_specific_after_fork): New macro (defined to no-op).
* pthread_support.c [CAN_HANDLE_FORK && THREAD_LOCAL_ALLOC]
(GC_remove_all_threads_but_me): Call GC_remove_specific_after_fork
instead of GC_remove_specific (i.e. delete thread-specific control data
for the given thread instead of the current one).
* win32_threads.c [CAN_HANDLE_FORK && THREAD_LOCAL_ALLOC] Like
* specific.c [USE_CUSTOM_SPECIFIC] (GC_setspecific): Add assertion that
the allocation lock is held; remove the corresponding comment.
* specific.c [USE_CUSTOM_SPECIFIC] (GC_remove_specific): Replace to
GC_remove_specific_after_fork (add t argument); replace self local
variable with t argument; update comment;
* specific.c [USE_CUSTOM_SPECIFIC && CAN_HANDLE_FORK]
(GC_remove_specific_after_fork): Add assertion that the allocation lock
is held; add comment.

Eliminate 'memory leak' code defect in remove_specific

* specific.c [LINT2] (GC_remove_specific): Call GC_noop1(entry) to
indicate that entry is lost (the memory will be collected during GC).

Simplify THREAD_TABLE_INDEX expression for Win32/64
(fix commit 85fce54)

Windows thread Id rarely has non-zero highest half of DWORD, so
it is OK to use only the lowest one for hash value computation.

* win32_threads.c (THREAD_TABLE_INDEX): Remove (id>>16) from the
expression.

Add debug logging to new_thread about GC_threads hash table collisions

* pthread_support.c [DEBUG_THREADS] (GC_new_thread): Call GC_log_printf
(with the appropriate message) if a GC_threads[] entry already exists
at the given hv index (excluding the detached threads those id is
already reused).
* win32_threads.c [DEBUG_THREADS] (GC_new_thread): Call GC_log_printf
to report that a new thread is created; call GC_log_printf (with the
appropriate message) if a GC_threads[] entry already exists at the
given hv index; remove useless comment about the result of
GC_INTERNAL_MALLOC.

Eliminate most of collisions in GC_threads on Linux/x64

On some targets (e.g., Linux/x64) pthread_t values always have zero
in the lowest byte (e.g. if pthread_t is actually a page-aligned
pointer) thus causing all the created thread descriptors to have
a collision at GC_threads[0].  This commit mixes 3 lowest bytes
of thread id with a XOR operation (thus greatly reduces the
probability of collisions in GC_threads).

* include/private/pthread_support.h (THREAD_TABLE_SZ): Do not
define if already defined; refine comment.
* pthread_support.c (THREAD_TABLE_INDEX): New macro (similar to that
in win32_threads.c).
* pthread_support.c (GC_new_thread, GC_delete_thread,
GC_delete_gc_thread, GC_lookup_thread): Replace
NUMERIC_THREAD_ID(id)%THREAD_TABLE_SZ to THREAD_TABLE_INDEX(id).
* pthread_support.c (GC_lookup_thread): Remove hv local variable.
* win32_threads.c (THREAD_TABLE_INDEX): Replace (id>>2) to
((id>>16)^(id>>8)^id).
* win32_threads.c [GC_PTHREADS] (GC_lookup_pthread): Define win32_id
local variable to pass it to THREAD_TABLE_INDEX() instead of passing
GET_PTHREAD_MAP_CACHE(id) directly.

Change type of THREAD_TABLE_INDEX result to int in win32_threads.c
(code refactoring)

* win32_threads.c (THREAD_TABLE_INDEX): Cast result to int; remove cast
of argument to word type; add comment.
* win32_threads.c (GC_new_thread, GC_delete_gc_thread_no_free,
GC_delete_thread): Change type of hv local variable from word to int.
* win32_threads.c (GC_lookup_thread_inner): Remove hv local variable;
remove "register" keyword for p local variable.
* win32_threads.c (GC_lookup_pthread): Change type of hv_guess local
variable from word to int.

Fix deadlock in GC_help_marker caused by use of mark_cv of parent process

The marker threads of the parent process are blocked on mark_cv at
fork.  So pthread_cond_wait() malfunction (hang) is possible in the
child process without mark_cv state cleanup (reinitialization).

* pthread_support.c [PARALLEL_MARK] (mark_cv): Move static variable
definition upper to be before GC_start_mark_threads_inner).
* win32_threads.c [GC_PTHREADS_PARAMARK] (mark_cv): Likewise.
* pthread_support.c [PARALLEL_MARK && CAN_HANDLE_FORK] (mark_cv):
Do not initialize statically; add comment.
* win32_threads.c [GC_PTHREADS_PARAMARK && CAN_HANDLE_FORK] (mark_cv):
Likewise.
* pthread_support.c [PARALLEL_MARK && CAN_HANDLE_FORK]
(GC_start_mark_threads_inner): Initialize mark_cv to
PTHREAD_COND_INITIALIZER (unless available_markers_m1 <= 0 or
GC_parallel); add comment.
* win32_threads.c [GC_PTHREADS_PARAMARK && CAN_HANDLE_FORK]
(GC_start_mark_threads_inner): Likewise.
* pthread_support.c [PARALLEL_MARK] (GC_wait_marker,
GC_notify_all_marker): Add assertion that GC_parallel is true (so
mark_cv is initialized).
* win32_threads.c [GC_PTHREADS_PARAMARK] (GC_wait_marker,
GC_notify_all_marker): Likewise.

Travis CI: Test some --enable-munmap configurations with disable incremental collection

Avoid busy waiting in mark_thread while GC_parallel is false

* mark.c [PARALLEL_MARK] (GC_help_marker): Add assertion that
GC_parallel is true (i.e. GC_markers_m1 is non-zero).
* pthread_support.c [PARALLEL_MARK && CAN_HANDLE_FORK]
(GC_start_mark_threads_inner): Set GC_markers_m1 value before starting
the first marker thread (it is already set if fork handling is off).
* win32_threads.c [GC_PTHREADS_PARAMARK && CAN_HANDLE_FORK]
(GC_start_mark_threads_inner): Likewise.
* pthread_support.c [PARALLEL_MARK] (GC_start_mark_threads_inner):
Adjust GC_markers_m1 value only if pthread_create failed.
* win32_threads.c [GC_PTHREADS_PARAMARK] (GC_start_mark_threads_inner):
Likewise.

Eliminate unsigned fl_builder_count underflow in mark_thread
(refactor commit 0ca6d3f)

* include/private/gc_priv.h [PARALLEL_MARK] (GC_fl_builder_count):
Change type from word to signed_word.
* reclaim.c [PARALLEL_MARK] (GC_fl_builder_count): Likewise.
* mark.c [PARALLEL_MARK] (GC_wait_for_markers_init): Change type of
count local variable to signed_word; add assertion that count is
non-negative.
* pthread_support.c [PARALLEL_MARK] (GC_mark_thread): Add comment that
GC_fl_builder_count can be negative here.
* win32_threads.c [PARALLEL_MARK] (GC_mark_thread): Likewise.
* reclaim.c [PARALLEL_MARK] (GC_fl_builder_count): Refine comment.

Add assertion that no hb_n_marks underflow occurs

Issue #177 (bdwgc).

* alloc.c (GC_clear_fl_marks): Add GC_ASSERT that hhdr->hb_n_marks
is non-zero before decrementing it.
* mark.c (GC_clear_mark_bit): Likewise.

Fix hb_n_marks underflow in clear_fl_marks if MARK_BIT_PER_OBJ

Issue #177 (bdwgc).

* mark.c [MARK_BIT_PER_OBJ] (GC_set_hdr_marks): Set hhdr->hb_n_marks
exactly to n_marks value (without a decrement by one).

Use MARK_BIT_PER_GRANULE instead of MARK_BIT_PER_OBJ where appropriate
(code refactoring)

* allchblk.c (setup_header): Use "ifdef MARK_BIT_PER_GRANULE" instead
of "ifndef MARK_BIT_PER_OBJ".
* mallocx.c (GC_realloc): Likewise.

Update ChangeLog file

Update ChangeLog file (v7.6 changes only)