The code was previously unused in non-debug builds.

btr_pcur_restore_position(): Add const qualifiers.

buf_LRU_block_remove_hashed_page(): Reduce the amount
of buf_page_hash_get() calls and add a UNIV_UNLIKELY hint
to an assertion-like test.

returns the compressed page size in kilobytes, not bytes.

about block->frame matching rec.

row_ins_check_foreign_constraint(): Pass the correct block to
the lock_ functions.

because the level of that page needs to be adjusted separately.

rec_get_nth_field_offs_old(): Split from rec_get_nth_field_old().

rec_get_nth_field_old(): Reimplement as a constness-preserving macro.

dict_drop_index_tree(), dict_truncate_index_tree(): Note that rec is
an in/out parameter, as the B-tree root page number will be updated.

page_get_page_no(page_align(field_ref)) calls with a local variable
rec_page_no = buf_block_get_page_no(rec_block).

#ifdef UNIV_BTR_DEBUG, as it depends on other #ifdef UNIV_BTR_DEBUG code.

Implement dict_index_get_if_in_cache_low() correctly.
Restore the function dict_index_get_if_in_cache() #ifdef UNIV_DEBUG.

buf0lru.c: Always #include "srv0srv.h"

buf_block_get_lock_mutex(), buf_frame_get_lock_mutex(): Remove.

mtr0log.ic: Remove #include "page0page.h" and replace the page_
functions with lower-level ones to break an #include cycle.

dict0dict.ic: Remove unnecessary #include "trx0undo.h" and "trx0sys.h"
that would create an #include cycle.

btr_check_node_ptr(): Replace page_t* parameter with buf_block_t*.

btr_free_externally_stored_field(): Add const qualifier to rec.
Remove an explicit buf_block_align() call, but replace an
mtr_memo_contains() with mtr_memo_contains_page().

row_upd_rec_sys_fields(): Reorder an assertion containing buf_block_align()
so that the costly call can be avoided in some cases.

with rec_t** current_rec.  Reposition *current_rec after calling
page_zip_reorganize().

from the adaptive hash index [btr_search_guess_on_hash() and
btr_search_validate()].  Some references to buf_block_align() remain
in debug builds.

btr_store_big_rec_extern_fields(): Add the parameter rec_block.

page_rec_get_next_low(): Do not assume that the page has been
allocated from the buffer pool when printing the diagnostic information.

page_cur_insert_rec_low(): Replace the parameter page_zip_des_t* page_zip
with the parameter buf_block_t* block.

Compare heap_no against PAGE_HEAP_NO_SUPREMUM instead of
PAGE_NEW_SUPREMUM or PAGE_OLD_SUPREMUM.

Return NULL when trying to use heap->free_block that is NULL.

Replace all page_t* parameters with buf_block_t*, and replace many
rec_t* parameters with heap_no.  This eliminates also many
rec_get_heap_no() calls, which became more expensive with the
introduction of ROW_FORMAT=COMPACT in MySQL/InnoDB 5.0.3.

page_rec_get_heap_no(), lock_get_min_heap_no(): New functions.

Replace buf_frame_t* guess with buf_block_t* guess in order to avoid
a buf_block_align() call.

trx_undo_t: Replace page_t* guess_page with buf_block_t* guess_block.

btr_search_t: Replace page_t* root_guess with buf_block_t* root_guess.

buf_calc_page_new_checksum(), buf_calc_page_old_checksum(),
buf_page_is_corrupted(), buf_page_print():
Add const qualifier to byte* parameter.

page_parse_create_zip(): Remove this declaration of non-existing function.

page_rec_check(), page_rec_print(), row_vers_impl_x_locked_off_kernel():
Add const qualifier to rec_t* parameter.

row_vers_old_has_index_entry(): Add const qualifier to dtuple_t* parameter.

row_sel_sec_rec_is_for_blob(): Add const qualifiers.

Replace some occurrences of mtr_memo_contains_page() with mtr_memo_contains().

After calling row_sel_sec_rec_is_for_blob(), skip the cmp_data_data()
comparison of the incomplete prefix.

page_set_max_trx_id(): Replace page_t* parameter with buf_block_t*,
to avoid a buf_block_align() call.

Replace some occurrences of page_get_page_no() with buf_block_get_page_no().

page_cur_delete_rec(): Replace buf_block_align() with page_cur_get_block().

btr_cur_pessimistic_insert(): Remove local variable "block".  Replace
an extraneous call to btr_cur_position() [with wrong "block", in r948]
with a debug assertion that the cursor is positioned on the preceding
record after the page split.

btr_pcur_restore_position(): Do not use btr_pcur_get_page(), because
the debug assertion there could fail.  This bug was introduced in r928.

parameters of some functions.

buf_block_get_frame(), because it will lead to debug assertion failure
when buf_fix_count == 0.  This bug was introduced in r908.

btr_cur_t: Move page_block to page_cur_t::block.

page_cur_get_block(), page_cur_get_page_zip(): New functions.

page_cur_position(): Add parameter block.

Remove many page_zip parameters, now that there is page_cur_get_page_zip().
Replace some page, page_zip parameters with block.

Add some const qualifiers to function parameters and remove casts.

PAGE_HEAP_NO_INFIMUM, PAGE_HEAP_NO_SUPREMUM, PAGE_HEAP_NO_USER_LOW:
New constants.

Replace some cursor code in low-level diagnostic functions with
direct management of rec, because buf_block_t::buf_fix_count may be 0
when the functions are called, and debug assertions would fail.

because it will lead to debug assertion failure when buf_fix_count == 0.
This bug was introduced in r912.

added in r928.  Do not call btr_cur_get_block() in the debug assertion,
because the debug assertion there would fail.

We cannot call buf_block_get_space() or buf_block_get_page_no(),
because the assertions there can fail.

while trying to fix r909: invoke mem_erase_buf() before freeing the
buffer, but after interpreting block->buf_block.

ibuf_page(), ibuf_page_low(), ibuf_free_excess_pages(), ibuf_insert(),
buf_read_page(), buf_read_ahead_linear(), buf_read_recv_pages():
Add parameter zip_size.

btr_search_build_page_hash_index(), fsp_parse_init_file_page(),
ibuf_parse_bitmap_init(): Replace page_t* with buf_block_t*.

buf_read_ibuf_merge_pages(): Add const qualifiers.  Retrieve zip_size.

ibuf_merge_or_delete_for_page(): Replace page_t* with buf_block_t*.
Add parameter zip_size.

dict_index_get_nth_col_pos(), dict_index_get_sys_col_pos(),
dict_index_get_n_fields(), fil_page_get_type():
Add const qualifier to parameter.

dict_index_get_nth_field(): Implement as a macro unless #ifdef UNIV_DEBUG.

accessors returning pointers with macros that preserve const qualifiers.
In UNIV_DEBUG builds, retain the accessors and cast away constness there.

dfield_get_type(), dfield_get_data(), dtuple_get_nth_field(),
dict_table_get_nth_col(), dict_table_get_sys_col(): Implement as macro
unless #ifdef UNIV_DEBUG.

rec_get_nth_field(): Replace with rec_get_nth_field_offs() that does not
do pointer arithmetics.  Implement rec_get_nth_field() as a macro.

passed as TRUE.

Enclose hash_table_t::adaptive and buf_block_t::n_pointers in
#ifdef UNIV_DEBUG.

btr_search_drop_page_hash_index(): Enclose the corruption check
(which depends on buf_block_t::n_pointers) in #ifdef UNIV_DEBUG.

calling buf_block_align() in btr_pcur_move_backward_from_page().
Also, enclose some assertions about page_is_comp() in #ifdef UNIV_BTR_DEBUG.