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Implement lookup switches in which a switch arm may contain more than one
solution, such as this code here:
p(d, "four", f1, 4.4).
p(e, "five", f2, 5.5).
p(e, "five2", f3(5), 55.5).
p(f, "six", f4("hex"), 6.6).
p(g, "seven", f5(77.7), 7.7).
p(g, "seven2", f1, 777.7).
p(g, "seven3", f2, 7777.7).
Such code occurs frequently in benchmark programs used to evaluate the
performance of tabled logic programming systems.
Change frameopt.m, which previously worked only on det and semidet code,
to also work for nondet code. For predicates such as the one above, frameopt
can now arrange for the predicate's nondet stack frame to be created only
when a switch arm that has more than one solution is selected.
compiler/lookup_switch.m:
Extend the existing code for recognizing and implementing lookup
switches to recognize and implement them even if they are model_non.
compiler/lookup_util.m:
New module containing utility predicates useful for implementing
both lookup switches, and in the future, lookup disjunctions (i.e.
disjunctions that correspond to a nondet arm of a lookup switch).
compiler/ll_backend.m:
Include the new module.
compiler/notes/compiler_design.html:
Mention the new module.
compiler/global_data.m:
Move the job of filling in dummy slots to our caller, in this case
lookup_switch.m.
compiler/frameopt.m:
Generalize the existing code for delaying stack frame creation,
which worked only on predicates that live on the det stack, to work
also on predicates that live on the nondet stack. Without this,
predicates whose bodies are model_non lookup switches would create
a nonstack stack frame before the switch is ever entered, which
is wasteful if the selected switch arm has at most one solution.
Since the structure of model_non predicates is more complex (you can
cause a branch to a label by storing its address in a redoip slot,
you can succeed from the frame without removing the frame), this
required considerable extra work. To make the new code debuggable,
record, for each basic block that needs a stack frame, *why* it
needs that stack frame.
compiler/opt_util.m:
Be more conservative about what refers to the stack. Export some
previously internal functionality for frameopt. Turn some predicates
into functions, and rename them to better reflect their purpose.
compiler/opt_debug.m:
Print much more information about pragma_c and call LLDS instructions.
compiler/prog_data.m:
Add an extra attribute to foreign_procs that says that the code
of the foreign_proc assumes the existence of a stack frame.
This is needed to avoid frameopt optimizing the stack frame away.
compiler/add_pragma.m:
When processing fact tables, we create foreign_procs that assume
the existence of the stack frame, so set the new attribute.
compiler/pragma_c_gen.m:
When processing foreign_procs, transmit the information in the
attribute to the generated LLDS code.
compiler/llds.m:
Rename the function symbols referring to the fixed slots in nondet
stack frames to make them clearer and to avoid overloading function
symbols such as curfr and succip.
Rename the function symbols of the call_model type to avoid overloading
the function symbols of the code_model type.
Add a new field to the c_procedure type giving the code_model of the
procedure, and give names to all the fields.
Describe the stack slots used by lookup switches to the debugger
and native gc.
compiler/options.m:
doc/user_guide.texi:
Add a new option, --debug-opt-pred-name, that does when the existing
--debug-opt-pred-id options does, but taking a user-friendly predicate
name rather than a pred_id as its argument.
compiler/handle_options.m:
Process --debug-opt-pred-name, and make --frameopt-comments imply
--auto-comments, since it is not useful without it.
Reformat some existing comments that were written in the days of
8-space indentation.
compiler/optimize.m:
Implement the new option.
Use the new field of the c_procedure type to try only the version
of frameopt appropriate for the code model of the current procedure.
Do a peephole pass after frameopt, since frameopt can generate code
sequences that peephole can optimize.
Make the mechanism for recording the process of optimizing procedure
bodies more easily usable by including the name of the optimization
that created a given version of the code in the name of the file
that contains that version of the code, and ensuring that all numbers
are two characters long, so that "vi procname*.opt*" looks at the
relevant files in the proper chronological sequence, instead of having
version 11 appear before version 2.
compiler/peephole.m:
Add a new optimization pattern: a "mkframe, goto fail" pair (which
can be generated by frameopt) should be replaced by a simple "goto
redo".
compiler/code_gen.m:
Factor out some common code.
compiler/llds_out.m:
Ensure that C comments nested inside comment(_) LLDS instructions
aren't emitted as nested C comments, since C compilers cannot handle
these.
compiler/code_info.m:
compiler/code_util.m:
compiler/continuation_info.m:
compiler/dupelim.m:
compiler/exprn_aux.m:
compiler/jumpopt.m:
compiler/livemap.m:
compiler/llds_out.m:
compiler/mercury_compile.m:
compiler/middle_rec.m:
compiler/ml_code_gen.m:
compiler/opt_debug.m:
compiler/opt_util.m:
compiler/peephole.m:
compiler/stack_layout.m:
compiler/transform_llds.m:
compiler/var_locn.m:
Conform to the change to prog_data.m, opt_util.m and/or llds.m.
compiler/handle_options.m:
Don't execute the code in stdlabel.m if doing so would cause a compiler
abort.
tests/hard_coded/dense_lookup_switch_non.{m,exp}:
New test case to exercise the new algorithm.
tests/hard_coded/Mmakefile:
Enable the new test case.
tests/hard_coded/cycles.m:
Make this test case conform to our coding convention.
88 lines
3.7 KiB
Mathematica
88 lines
3.7 KiB
Mathematica
%-----------------------------------------------------------------------------%
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% vim: ft=mercury ts=4 sw=4 et
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%-----------------------------------------------------------------------------%
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% Copyright (C) 2000, 2003-2006 The University of Melbourne.
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% This file may only be copied under the terms of the GNU General
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% Public License - see the file COPYING in the Mercury distribution.
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%-----------------------------------------------------------------------------%
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%
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% This module defines the `code_model' data type, and associated procedures.
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% The `code_model' type is a simplified version of the `determinism' type
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% that is defined in prog_data.m. It ignores most of the distinctions in
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% the determinism type and keeps only the distinctions that are important
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% for code generation.
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%
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% We define this in a different module than the `determinism' type because
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% it is only used by some of the different back-ends, not all of them.
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% It is used by the MLDS, LLDS, and bytecode back-ends.
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%
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%-----------------------------------------------------------------------------%
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:- module hlds.code_model.
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:- interface.
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:- import_module hlds.hlds_goal.
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:- import_module hlds.hlds_pred.
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:- import_module parse_tree.prog_data.
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:- type code_model
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---> model_det % functional & total
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; model_semi % just functional
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; model_non. % not functional
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:- pred determinism_to_code_model(determinism, code_model).
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:- mode determinism_to_code_model(in, out) is det.
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:- mode determinism_to_code_model(out, in) is multi.
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:- pred proc_info_interface_code_model(proc_info::in, code_model::out) is det.
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:- pred goal_info_get_code_model(hlds_goal_info::in, code_model::out) is det.
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% Construct a representation of the interface determinism of a procedure.
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% The code we have chosen is not sequential; instead it encodes the various
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% properties of each determinism. This must match the encoding of
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% MR_Determinism in mercury_stack_layout.h.
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%
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% The 8 bit is set iff the context is first_solution.
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% The 4 bit is set iff the min number of solutions is more than zero.
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% The 2 bit is set iff the max number of solutions is more than zero.
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% The 1 bit is set iff the max number of solutions is more than one.
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%
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:- func represent_determinism(determinism) = int.
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%-----------------------------------------------------------------------------%
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:- implementation.
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:- import_module mdbcomp.program_representation.
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:- import_module int.
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determinism_to_code_model(det, model_det).
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determinism_to_code_model(semidet, model_semi).
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determinism_to_code_model(nondet, model_non).
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determinism_to_code_model(multidet, model_non).
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determinism_to_code_model(cc_nondet, model_semi).
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determinism_to_code_model(cc_multidet, model_det).
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determinism_to_code_model(erroneous, model_det).
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determinism_to_code_model(failure, model_semi).
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proc_info_interface_code_model(ProcInfo, CodeModel) :-
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proc_info_interface_determinism(ProcInfo, Determinism),
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determinism_to_code_model(Determinism, CodeModel).
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goal_info_get_code_model(GoalInfo, CodeModel) :-
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goal_info_get_determinism(GoalInfo, Determinism),
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determinism_to_code_model(Determinism, CodeModel).
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represent_determinism(det) = detism_rep(det_rep).
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represent_determinism(semidet) = detism_rep(semidet_rep).
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represent_determinism(nondet) = detism_rep(nondet_rep).
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represent_determinism(multidet) = detism_rep(multidet_rep).
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represent_determinism(erroneous) = detism_rep(erroneous_rep).
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represent_determinism(failure) = detism_rep(failure_rep).
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represent_determinism(cc_nondet) = detism_rep(cc_nondet_rep).
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represent_determinism(cc_multidet) = detism_rep(cc_multidet_rep).
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%-----------------------------------------------------------------------------%
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