[PATCH]: Change function_section to allow partitioning w/o insn stream scanning

[Caroline Tice <ctice at apple dot com>]

As part of my work fixing the hot/cold partitioning optimization, I 
need to change the function
"function_section" in varasm.c.  The problem I'm trying to solve is 
that "function_section" is really used
for two different pieces of functionality:  1.  Change to the same text 
section as should be used for the first basic block/code in the current 
function; and 2. Change to the most recent text section.  As long as 
we're not doing hot/cold partitioning those two are the same, so it's 
not a problem.  When we do hot/cold partitioning sometimes the first 
case should be the hot text section and the second case should be the 
cold text section.

This patch addresses that problem by splitting function_section into 
two functions:  "function_section" will change to the same text section 
as should be used for the first basic block/code in the current 
function;  and "current_function_section" will change to the most 
recent text section (within the current function).  I have
also examined all the original calls to function_section to identify 
which ones should really call
current_function_section, and have changed them to do so (except for 
the calls in dwarf2out.c; I will fix those when I fix the dwarf 
debugging stuff to work with hot/cold partitioning).

This patch is a necessary step towards removing the instruction stream 
searching that hot/cold
partitioning does.

I have tested this patch by doing a profiled bootstrap on both a G4 
running apple powerpc darwin, and an x86 box running Linux.  I have 
also run DejaGnu tests on both platforms (with no regressions).

Is this okay to commit to FSF mainline?

-- Caroline Tice
ctice@apple.com


2004-08-31  Caroline Tice  <ctice@apple.com>

        * cfgrtl.c (rtl_verify_flow_info_1): Add EDGE_CROSSING flag to
        test case.
        * dbxout.c (FORCE_TEXT): Change call to function_section into 
call to
        current_function_section.
        * except.c (output_function_exception_table): Likewise.
        * final.c (profile_function): Likewise.
        (final_scan_insn): Likewise (multiple times).
        * output.h (current_function_section): Add new function 
declaration.
        * varasm.c (last_text_section): New global variable.
        (last_text_section_name):  New global variable.
        (text_section):  Add code to set last_text_section.
        (initialize_cold_section_name):  New function.
        (unlikely_text_section):  Change to call 
initialize_cold_section_name;
        add code to set last_text_section.
        (named_section):  Set last_text_section and 
last_text_section_name, if
        appropriate.
        (function_section): Remove code that scanned ahead to determine 
which
        section to use; revert to using section from function decl.
        (current_function_section): New function.
        (assemble_start_function): Add call to 
initialize_cold_section_name;
        set function decl section to cold section if appropriate.
        * config/s390/s390.c (s390_select_rtx_section):  Change call to
        function_section into call to current_function_section.
        * config/sparc/sparc.c (sparc_output_deferred_case_vectors): 
Likewise.
        * config/stormy16/stormy16.c (xstormy16_output_addr_vec): 
Likewise.
        * config/xtensa/xtensa.c (override_options):  Turn off hot/cold
        partitioning for this architecture.

Attachment: gcc5-hot-cold2.txt
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