Re: [PATCH] New fixes for hot/cold partitioning

[Caroline Tice <ctice at apple dot com>]

Okay, let's try it again.  :-) I have tried to address everyone's
concerns about the hot/cold partitioning patch I submitted on Monday.
Here's an updated version of the patch.  It does the following things
differently:

- Turn off partitioning flag if not targetm.have_named_sections (and
  remove all the target,have_named_sections tests that this makes
  superfluous)

- Adds unlikely_text_section_name as field in function struct, and
  updates code to use this (and keeps it a char* rather than an array).

- Adds calls to strip_name_encoding before building up cold section
  name.

As well as doing the following things the other patch did;

> - It makes the hot/cold section labels be pointed to by fields in the
>    function struct.
> - It uses ASM_GENERATE_INTERNAL_LABEL to generate the values for these
>   labels.
> - It changes the argument passed to ASM_SELECT_SECTION from 'bool
>   unlikely' to 'int reloc' in both current_function_section and
>   function_section.
> - It updates dbxout.c and dwarf2out.c to get the section labels from
>   the function record for the current function.
> - It adds cold_text_section_label, cold_end_label and the
>   corresponding macros to dwarf2out.c, and uses them appropriately.
> - It removes or updates some incorrect code I had previously
>   written in dwarf2out.c
> - It checks the partitiong flag before calling
>   verify_hot_cold_block_grouping.


I am running tests on both an x86 running Linux and a Apple G4 running
powerpc Darwin.  So far it has passed the profiledbootstrap with
partitionining, and I'm in the process of running the
profiledbootstrap without partitioning but with reordering.  I will
also run a regular bootstrap and the DejaGnu tests, as well as some
SPEC2000 benchmarks with partitioning.  Assuming it passes all the
tests, is this okay to commit to FSF mainline?

-- Caroline Tice
ctice@apple.com


2005-04-06  Caroline Tice  <ctice@apple.com>

        * bb-reorder.c 
(find_rarely_executed_basic_blocks_and_crossing_edges):
        Remove targetm.have_named_sections test.
        (fix_edges_for_rarely_executed_code): Likewise.
        (insert_section_boundary_note): Likewise.
        (reorder_basic_blocks): Check partitioning flag before calling
        verify_hot_cold_block_grouping.
        * dbxout.c (dbxout_function_end): Get hot/cold section labels 
from
        the function struct rather than global variables.
        * dwarf2out.c (COLD_TEXT_SECTION_LABEL): New macro.
        (COLD_END_LABEL): Likewise
        (cold_text_section_label): New static global variable.
        (cold_end_label): Likewise.
        (dwarf2out_switch_text_section): Get hot/cold section labels 
from
        the function struct rather than global variables.
        (output_aranges): Use cold_text_section_label and 
cold_end_label;
        check partitioning flag before putting out delta.
        (output_ranges): Remove incorrect code attempting to use
        hot/cold labels.
        (output_line_info): Get cold section label from function struct.
        (add_location_or_const_value_attribute): Likewise.
        (get_subprogram_die): Get hot/cold section labels from function 
struct.
        (dwarf2out_var_location): Likewise.
        (dwarf2out_init): Generate cold_text_section_label and 
cold_end_label;
        write out cold_text_section_label if partition flag is set.
        (dwarf2out_finish): Write out cold_end_label if partition flag 
is set;
        * function.h (struct function): Add new fields to point to 
hot/cold
        section labels: hot_section_label, cold_section_label,
        hot_section_end_label and cold_section_end_label; also add new 
field
        for cold text section name, unlikely_text_section_name.
        * opts.c (decode_options): Turn off partitioning flag if
        !targetm.have_named_sections.
        * output.h (hot_section_label): Remove.
        (hot_section_end_label): Remove.
        (cold_section_end_label): Remove.
        (unlikely_section_label): Remove.
        (unlikely_text_section_name): Remove.
        * passes.c (rest_of_handle_final):  Remove code that frees
        unlikely_text_section_name.
        * varasm.c (unlikely_section_label): Remove.
        (hot_section_label): Remove.
        (hot_section_end_label): Remove.
        (cold_section_end_label): Remove.
        (unlikely_text_section_name):  Remove.
        (initialize_cold_section_name): Modify to call
        targetm.strip_name_encoding; to store cold section name in 
current
        function struct, if it exists; and to only use the 
decl_section_name
        if flag_named_sections is true.
        (unlikely_text_section): Modify to get section name out of 
current
        function struct, if there is one; otherwise build it from
        UNLIKELY_EXECUTED_TEXT_SECTION_NAME.
        (in_unlikely_text_section): Likewise.
        (named_section): Modify to get/put cold section name in current 
function
        struct, if there is one.
        (function_section):  Change 'bool unlikely' to 'int reloc'; 
check
        targetm.have_named_sections before calling named_section.
        (current_function_section): Likewise.
        (assemble_start_function): Modify to get/put 
unlikely_text_section_name
        in current function struct; modify to get hot/cold section 
labels
        from function struct; initialize labels using 
ASM_GENERATE_INTERNAL_LABEL;
        test partitioning flag before writing out hot section label.
        (assemble_end_function): Test partitioning flag before writing 
out
        hot/cold section labels.
        (default_section_type_flags_1):  Modify to use array instead of
        char* for unlikely_text_section_name; set flags correctly for
        cold text section if there is not a current function decl.

Attachment: gcc5-hot-cold.txt
Description: Text document