## solve-register-allocation-problems-by-recursive-partition-g.pkg "regor" is a contraction of "register allocator"
#
# Most register allocators choke and die if given
# a controlflow graph which is too large.
#
# The idea here is to take graphs which are "too large"
# and break them down into manageable-sized pieces
# which can then be register-allocated individually.
# Compiled by:
# src/lib/compiler/back/low/lib/lowhalf.lib# This generic is nowhere invoked.
generic package solve_register_allocation_problems_by_recursive_partition_g
# ===========================================================
#
# This is the vanilla register allocator:
#
(ra: Solve_Register_Allocation_Problems) # Solve_Register_Allocation_Problems is from src/lib/compiler/back/low/regor/solve-register-allocation-problems.api # This is the controlflow-graph partitioner:
#
# partition_machcode_controlflow_graph_and_allot_registers_by_partition_g is from src/lib/compiler/back/low/regor/partition-machcode-controlflow-graph-and-allot-registers-by-partition-g.pkg # Partition_Machcode_Controlflow_Graph_And_Allot_Registers_By_Partition is from src/lib/compiler/back/low/regor/partition-machcode-controlflow-graph-and-allot-registers-by-partition.api (fp: Partition_Machcode_Controlflow_Graph_And_Allot_Registers_By_Partition
where
rgk == ra::rgk # "rgk" == "registerkinds".
also Machcode_Controlflow_Graph == ra::flo::Machcode_Controlflow_Graph
)
: (weak) Solve_Register_Allocation_Problems # Solve_Register_Allocation_Problems is from src/lib/compiler/back/low/regor/solve-register-allocation-problems.api{
# Exported to client packages:
#
package flo = ra::flo;
package mcf = flo::mcf; # "mcf" == "machcode_form" (abstract machine code).
package rgk = mcf::rgk; # "rgk" == "registerkinds".
#
include package ra;
stipulate
package cig = iterated_register_coalescing::cig; # iterated_register_coalescing is from src/lib/compiler/back/low/regor/iterated-register-coalescing.pkg herein
max_blocks
=
lowhalf_control::make_int ("ra-max-blocks", "max block count for region-based RA");
# Main entry point.
# All the magic is actually done in
# partition_machcode_controlflow_graph_and_allot_registers_by_partition_g is from src/lib/compiler/back/low/regor/partition-machcode-controlflow-graph-and-allot-registers-by-partition-g.pkg #
fun solve_register_allocation_problems
#
(register_allocation_problems: List(Register_Allocation_Problem))
#
mcg # "mcg" == "machcode_controflow_graph".
=
if (fp::number_of_basic_blocks_in mcg <= *max_blocks)
#
ra::solve_register_allocation_problems register_allocation_problems mcg;
else
apply ra register_allocation_problems
where
fun ra (register_allocation_problem as { registerkind, ... } )
=
fp::partition_machcode_controlflow_graph_and_allot_registers_by_partition
#
mcg
#
registerkind
#
(ra::solve_register_allocation_problems [ register_allocation_problem ])
;
end;
mcg;
fi;
end;
};