Estimated hours taken: 4
Fix some old problems with HLDS dumps, including blank lines between goals
(using vi's paragraph commands to move between predicates now works),
unescaped characters in strings and chars in unifications, and extra dots
in type definitions.
compiler/hlds_out.m:
Make the above fixes. To fix the problem of blank lines between goals,
we reinterpret the meaning of the Follow arguments of several
predicates that print goals, which say what to print after the
goal, to include the newline to print after the goal. This avoids
lots of separate calls to io__write_string("\n").
Document the meanings of the arguments of many predicates.
compiler/prog_out.m:
Modify prog_out__write_sym_name to escape any special characters
(e.g. newlines) in the symbols written. (Strings, as cons_ids,
are printed as symbols.)
Add a new predicate for printing a symbol with single forward quotes
around it.
compiler/mercury_to_mercury:
When printing cons_id, quote strings.
compiler/constraint.m:
compiler/mode_errors.m:
compiler/pd_debug.m:
compiler/rl_dump.m:
compiler/saved_vars.m:
Conform to the new meaning of the Follow arguments in hlds_out.m.
Estimated hours taken: 20
These changes make `var' and `term' polymorphic. This allows us to make
variables and terms representing types of a different type to those
representing program terms and those representing insts.
These changes do not *fix* any existing problems (for instance
there was a messy conflation of program variables and inst variables,
and where necessary I've just called varset__init(InstVarSet) with
an XXX comment).
NEWS:
Mention the changes to the standard library.
library/term.m:
Make term, var and var_supply polymorphic.
Add new predicates:
term__generic_term/1
term__coerce/2
term__coerce_var/2
term__coerce_var_supply/2
library/varset.m:
Make varset polymorphic.
Add the new predicate:
varset__coerce/2
compiler/prog_data.m:
Introduce type equivalences for the different kinds of
vars, terms, and varsets that we use (tvar and tvarset
were already there but have been changed to use the
polymorphic var and term).
Also change the various kinds of items to use the appropriate
kinds of var/varset.
compiler/*.m:
Thousands of boring changes to make the compiler type correct
with the different types for type, program and inst vars and
varsets.
Estimated hours taken: 400
Deforestation.
This increases the code size of the compiler by ~80k when compiling
with --intermodule-optimization --deforestation.
The improvement from deforestation is not measurable for mmc -C make_hlds.m.
Compile time for make_hlds.m increased from 50.7 seconds to 52.2 seconds
when running deforestation.
compiler/simplify.m
compiler/common.m
Provide a nicer interface for simplifying a goal,
not an entire procedure.
Rework the interface to avoid manipulating lots of booleans.
Return an estimate of the improvement in cost from simplification.
Remove failing cases and disjuncts.
Add an option to optimize common structures even across calls.
Remove code to merge branched goals, since that is now
done by deforestation.
Fix a bug: the code to collect instmap_deltas for cases was not
including the switched-on variable in the instmap_delta,
which caused an abort in merge_instmap_delta if the switched
on variable was further instantiated in the switch.
This came up while compiling the compiler with --deforestation.
compiler/det_report.
Output duplicate call warnings even if --warn-simple-code is not set.
XXX fix the same problem with `:- pragma obsolete'.
compiler/code_aux.m
Update code_aux__cannot_loop to use termination information.
compiler/hlds_pred.m
compiler/dnf.m
Pass the type_info_varmap and typeclass_info_varmap
into hlds_pred__define_new_pred.
Restrict the variables of the new procedure onto the variables
of the goal.
Make sure all relevant type_infos are passed into the new
procedure if --typeinfo-liveness is set.
compiler/modes.m
compiler/unique_modes.m
compiler/mode_info.m
compiler/modecheck_unify.m
Put `how_to_check_goal' into the mode_info, rather
than passing it around.
Add a field to the `check_unique_modes' case which
controls whether unique modes is allowed to choose
a different procedure. For deforestation, this is
not allowed, since it could result in choosing a less
efficient procedure after generalisation.
compiler/options.m
New options:
--deforestation
--deforestation-depth-limit
Safety net for termination of the algorithm.
--deforestation-cost-factor
Fudge factor for working out whether deforestation
was worthwhile.
--deforestation-vars-threshold
Like --inline-vars-threshold.
Enable deforestation at -O3.
Removed an unnecessary mode for option_defaults_2, since it
resulted in a warning about disjuncts which cannot succeed.
compiler/handle_options.m
--no-reorder-conj implies --no-deforestation.
compiler/inlining.m
Separate code to rename goals into inlining__do_inline_call.
compiler/hlds_goal.m
Added predicates goal_list_nonlocals, goal_list_instmap_delta
and goal_list_determinism to approximate information about
conjunctions.
compiler/hlds_module.m
Added module_info_set_pred_proc_info to put an updated
pred_info and proc_info back into the module_info.
compiler/hlds_out.m
Exported hlds_out__write_instmap for debugging of deforestation.
Bracket module names on constructors where necessary.
compiler/mercury_compile.m
Call deforestation.
Use the new interface to simplify.m.
compiler/intermod.m
Put recursive predicates with a top-level branched goal
into `.opt' files.
goal_util.m
Added goal_calls_pred_id to work out if a predicate is
recursive before mode analysis.
Export goal_util__goals_goal_vars for use by deforestation.
Give a better message for a missing variable in a substitution.
compiler/instmap.m
Give a better message for inst_merge failing.
compiler/notes/compiler_design.m
Document the new modules.
library/varset.m
Add varset__select to project a varset's names and values
onto a set of variables.
doc/user_guide.texi
Document deforestation.
Remove a reference to a non-existent option, --no-specialize.
util/mdemangle.c
profiler/demangle.m
tests/misc_tests/mdemangle_test.{exp,inp}
Handle the `DeforestationIn__' predicate names introduced by
deforestation, similar to the `IntroducedFrom__' for lambda goals.
New files:
deforest.m Deforestation.
pd_cost.m Cost estimation.
pd_debug.m Debugging output.
pd_info.m State type and version control.
pd_term.m Termination checking.
pd_util.m Utility predicates
