Estimated hours taken: 14
Implemented a :- use_module directive. This is the same as
:- import_module, except all uses of the imported items
must be explicitly module qualified.
:- use_module is implemented by ensuring that unqualified versions
of items only get added to the HLDS symbol tables if they were imported
using import_module.
Indirectly imported items (from `.int2' files) and items declared in `.opt'
files are treated as if they were imported with use_module, since all uses
of them should be module qualified.
compiler/module_qual.m
Keep two sets of type, mode and inst ids, those which can
be used without qualifiers and those which can't.
Renamed some predicates which no longer have unique names since
'__' became a synonym for ':'.
Made mq_info_set_module_used check whether the current item is in
the interface, rather than relying on its caller to do the check.
Removed init_mq_info_module, since make_hlds.m now uses the
mq_info built during the module qualification pass.
compiler/prog_data.m
Added a pseudo-declaration `used', same as `imported' except uses of
the following items must be module qualified.
Added a type need_qualifier to describe whether uses of an item
need to be module qualified.
compiler/make_hlds.m
Keep with the import_status whether current item was imported
using a :- use_module directive.
Use the mq_info structure passed in instead of building a new one.
Ensure unqualified versions of constructors only get added to the
cons_table if they can be used without qualification.
compiler/hlds_module.m
Added an extra argument to predicate_table_insert of type
need_qualifier.
Only add predicates to the name and name-arity indices if they
can be used without qualifiers.
Changed the structure of the module-name-arity index, so that
lookups can be made without an arity, such as when type-checking
module qualified higher-order predicate constants. This does not
change the interface to the module_name_arity index.
Factored out some common code in predicate_table_insert which
applies to both predicates and functions.
compiler/hlds_pred.m
Removed the opt_decl import_status. It isn't needed any more
since all uses of items declared in .opt files must now be
module qualified.
Added some documentation about when the clauses_info is valid.
compiler/intermod.m
Ensure that predicate and function calls in the `.opt' file are
module qualified. Use use_module instead of import_module in
`.opt' files.
compiler/modules.m
Handle use_module directives.
Report a warning if both use_module and import_module declarations
exist for the same module.
compiler/mercury_compile.m
Collect inter-module optimization information before module
qualification, since it can't cause conflicts any more. This means
that the mq_info structure built in module_qual.m can be reused in
make_hlds.m, instead of building a new one.
compiler/prog_out.m
Add a predicate prog_out__write_module_list, which was moved
here from module_qual.m.
compiler/typecheck.m
Removed code to check that predicates declared in `.opt' files
were being used appropriately, since this is now handled by
use_module.
compiler/*.m
Added missing imports, mostly for prog_data and term.
NEWS
compiler/notes/todo.html
doc/reference_manual.texi
Document `:- use_module'.
tests/valid/intermod_lambda_test.m
tests/valid/intermod_lambda_test2.m
tests/invalid/errors.m
tests/invalid/errors2.m
Test cases.
Estimated hours taken: 3
Replace calls to map__set with calls to either map__det_insert or
map__det_update. In some cases this required a small amount of code
reorganization.
Estimated hours taken: 3
code_gen, pragma_c_code:
Move the code that generates code for pragma_c_codes to a new module.
llds:
Change the representation of reg and temp lvals, in order to create
the concept of a "register type" and to reduce memory requirements.
Also add a comment indicating a possible future extension dealing with
model_non pragma_c_codes.
code_exprn, code_info:
Add the ability to request registers of a given type, or a specific
register, when acquiring registers.
bytecode, bytecode_gen, call_gen, dupelim, exprn_aux, follow_vars, frameopt,
garbage_out, jumpopt, llds_out, middle_rec, opt_debug, opt_util, store_alloc,
string_switch, tag_switch, unify_gen, vn_block, vn_cost, vn_filter, vn_flush,
vn_order, vn_temploc, vn_type, vn_util, vn_verify:
Small changes to accommodate the new register representation.
hlds_goal:
Add a comment indicating a possible future extension dealing with
model_non pragma_c_codes.
inlining:
Add a comment indicating a how to deal with a possible future extension
dealing with model_non pragma_c_codes.
Estimated hours taken: _____
Take the code generator a big step closer to notes/ALLOCATION.
The new code generator emits code that is smaller and faster than
the code we used to emit.
Nondet liveness is no longer used; nondet live sets are always empty.
In code that was being modified anyway, remove its handling. Other
uses will be removed later (this keeps this change from being far too big;
as it is it is merely too big). Similarly for cont-lives.
In several places, clarify the code that gathers several code pieces together.
call_gen:
Unset the failure continuation and flush the resume vars to
their stack slots before nondet calls.
Move the code that decides whether a nondet call can be a tailcall
to code_info.
code_aux:
Remove the code to handle resume points, since these are now
handled in the specific constructs that need them. Replace it
with a sanity check.
code_exprn:
Add a predicate to place multiple vars.
code_gen:
Remove the predicate code_gen__generate_forced_goal, since it
packaged together some operations that should be executed at different
times.
Don't unset the failure continuation after every nondet goal;
this is now done in the constructs that need it.
Modify the handling of negation to use resume point info
according to notes/ALLOCATION.
Remove the predicate code_gen__ensure_vars_are_saved which was
use to save all lives variables to the stack before nondet
disjunctions and if-then-elses; we don't do that anymore.
code_info:
Significantly simplify and document the handling of failure
continuations, and make the types involved abstract types.
Factor out common code in the handling of det and semi commits.
Keep track of "zombies", variables that are dead wrt forward
execution but whose values we need because they may be needed
at a resume point we can reach.
Remove several now unneeded predicates, and introduce new
predicates to help other modules.
code_util:
Add a couple of predicates to check whether ia goal cannot fail before
flushing all variables to the stack, and whether a goal cannot flush
any variables to the stack. These are used in liveness to decide
which entry labels will be needed at resume points.
disj_gen:
Unify the handling of det and semi disjunctions. Model the code
handling of nondet disjunctions on the code handling pruned
disjunctions. It is possible that the handling of nondet and pruned
disjunctions can also be unified; the new code should make this
significantly easier.
Make the code conform to notes/ALLOCATION. This means saving
only the variables mentioned in the resume_point field, not
flushing all live variables to the stack at the start of a
nondet disjunction, handling zombies, and using the new method
of flushing variables at the ends of branched structures.
ite_gen:
Unify the handling of det and semi if-then-elses. Model the code
handling of nondet if-then-elses on the code handling det/semi
if-then-elses. It is possible that the handling of nondet and pruned
if-then-elses can also be unified; the new code should make this
significantly easier.
Make the code conform to notes/ALLOCATION. This means saving
only the variables mentioned in the resume_point field, not
flushing all live variables to the stack at the start of a
nondet if-then-else, handling zombies, and using the new method
of flushing variables at the ends of branched structures.
Apply the new rules about liveness in if-then-elses, which say that
the else part is parallel not to the then part but to the conjunction
of the condition and the then part.
dense_switch, lookup_switch, string_switch, switch_gen, tag_switch, middle_rec:
Use the new method of flushing variables at the ends of branched
structures. Don't call remake_with_store map; switch_gen will do so.
Fix an old bug in lookup_switch.
The code in switch_gen which looked for the special case of a two-way
switch used to use a heuristic to decide which one was recursive and
which one was a base case. We now check the codes of the cases.
hlds_goal:
Adjust the structure of the resume_point field to make it easier
to use. Add a more convenient access predicate.
hlds_out:
Don't print the nondet liveness and cont live fields, since they are
not used anymore. Comment out the printing of the context field,
which is rarely useful. Modify the printing of the resume_point field
to conform to its new definition.
live_vars:
Use the resume_point field, not the nondetlives field, to decide
which variables may be needed on backward execution. Remove some
code copied from liveness.m.
liveness:
Put the several pieces of information we thread through the traversal
predicates into a single tuple.
Don't put variables which are local to one branch of a branched
structure into the post-birth sets of other branches.
Apply the new rules about liveness in if-then-elses, which say that
the else part is parallel not to the then part but to the conjunction
of the condition and the then part. Variables that are needed in the
else part but not in the condition or the then part now die in at the
start of the condition (they will be protected by the resume point on
the condition).
We now treat pruned and non-pruned disjunctions the same way
wrt deadness; the old way was too conservative (it had to be).
We still mishandle branches which produce some variables but
can't succeed.
mercury_compile:
Liveness now prints its own progress message with -V; support this.
store_alloc:
When figuring out what variables need to be saved across calls,
make sure that we put in interference arcs between those variables
and those that are required by enclosing resume points.
Don't compute cont-lives, since they are not used anymore.
livemap:
Fix the starting comment.
Estimated hours taken: 2.5
Switch from using a stack of store_maps in the code_info to govern what
goes where at the end of each branched structure to using the store map
fields of the goal expressions of those structures.
Fix variable names where they resembled the wrong kind of map(var, lval).
code_info:
Remove the operations on stacks of store maps.
Modify the generate_forced_saves and remake_with_store_map operations
to take a store_map parameter.
When making variables magically live, pick random unused variables
to hold them, since we can no longer use the guidance of the top
store map stack entry. This may lead to the generation of some
excess move instructions at non-reachable points in the code;
this will be fixed later.
code_gen:
Remove the store map push and pop invocations.
Modify the generate_forced_goal operation to take a store_map parameter.
code_exprn:
Export a predicate for use by code_info.
middle_rec, disj_gen, ite_gen, switch_gen,
dense_switch, lookup_switch, string_switch, tag_switch:
Pass the store map around to get it to invocations of the primitives
in code_gen and code_info that now need it.
goal_util:
Name apart the new follow_vars field in hlds__goal_infos.
(This should have been in the change that introduced that field.)
common, constraint, cse_detection, det_analysis, dnf, excess, follow_code,
intermod, lambda, lco, liveness, make_hlds, mode_util, modes, polymorphism,
quantification, simplify, switch_detection, typecheck, unique_modes,
unused_args:
Fix variable names.
follow_vars, store_alloc:
Add comments.
Estimated hours taken: 15
hlds_data:
Rename address_const to code_addr_const, and add base_type_info_const
as a new alternative in cons_id, and make corresponding changes
to cons_tag.
Make hlds_type__defn an abstract type.
llds:
Rename address_const to code_addr_const, and add data_addr_const
as a new alternative in rval_const.
Change type "label" to have four alternatives, not three:
local/2 (for internal labels), c_local (local to a C module),
local/1 (local a Mercury module but not necessarily to a C module,
and exported.
llds_out:
Keep track of the things declared previously, and don't declare them
again unnecessarily. Associate indentation with the following item
rather than the previous item (the influence of 244); this results
in braces being put in different places than previously, but should be
easier to maintain. Handle the new forms of addresses and labels.
Refer to c_local labels as STATIC when not using --split-c-files.
code_info:
Use a presently junk field to store a cell counter, which is used
to allocate distinguishing numbers to create'd cells. Previously
we used the label counter, which meant that label numbers changed
when we optimized away some creates. Handle the new forms of
addresses and labels.
exprn_aux:
Handle the new forms of addresses and labels. We are now more
precise in figuring out what label address forms will be considered
constants by the C compilers.
others:
Changes to handle the new forms of addresses and labels, and/or to
access hlds_type__defn as an abstract type.
Estimated hours taken: 2
llds.m:
Add a boolean argument to the create rval, which should be set to true
if the cell created must have a unique reference.
vn_type.m:
Add a corresponding argument to vn_create.
others:
Fix references to creates and vn_creates.
Estimated hours taken: 0.5 hours for the fix, 8 hours debugging
(plus a similar amount of Zoltan's time debugging)
string_switch.m:
Fix a code generation bug: it called
code_info__generate_failure from the wrong spot, and so used
the wrong exprn_info. This meant that the code generated
by generate_failure contained incorrect register shuffling,
since it thought the variables were in different locations
to where they really were.
Estimated hours taken: 10
hlds, hlds_module, hlds_pred, hlds_goal, hlds_data:
Divided the old hlds.m into four files:
hlds_module.m defines the data structures that deal with issues
that are wider than a single predicate. These data structures are
the module_info structure, dependency_info, the predicate table
and the shape table.
hlds_pred.m defined pred_info and proc_info, pred_id and proc_id.
hlds_goal.m defines hlds__goal, hlds__goal_{expr,info}, and the
other parts of goal structures.
hlsd_data.m defines the HLDS types that deal with issues related
to data and its representation: function symbols, types, insts, modes.
It also defines the types related to determinism.
hlds.m is now an empty module. I have not removed it from CVS
because we may need the name hlds.m again, and CVS does not like
the reuse of a name once removed.
other modules:
Import the necessary part of hlds.
det_analysis:
Define a type that was up to now improperly defined in hlds.m.
prog_io:
Move the definition of type determinism to hlds_data. This decision
may need to be revisited when prog_io is broken up.
dnf, lambda:
Simplify the task of defining predicates.
llds:
Fix some comments.
mercury_compile:
If the option -d all is given, dump all HLDS stages.
shape, unused_args:
Fix formatting.
excess:
A new pass to remove unnecessary assignment unifications.
mercury_compile:
Call the new excess assignment module.
options:
Add a new option, excess_assign, to control the new optimization.
Add another, num-real-regs, to specify how many of r1, r2 etc are
actually real registers. The default is now set to 5 for kryten;
later it should be supplied by the mc script, with a value determined
at configuration time.
tag_switch:
Use num-real-regs to figure out whether it is likely to be worthwhile
to eliminate the common subexpression of taking the primary tag of
a variable. Also fix an old performance bug: the test for when a
jump table is worthwhile was reversed.
value_number, vn_block:
Do value numbering on extended basic blocks, not basic blocks.
vn_debug:
Modify an information message.
labelopt:
Clean up an export an internal predicate for value numbering. Replace
bintree_set with set.
middle_rec:
Prepare for the generalization of middle recursion optimization
to include predicates with an if-then-else structure.
cse_detection:
Fix a bug: when hoisting a common desconstruction X = f(Yi), create
new variables for the Yi. This avoids problems with any of the Yis
appearing in other branches of the code.
goal_util:
Add a new predicate for use by cse_detection.
common:
Fix a bug: recompute instmap deltas, since they may be affected by the
optimization of common structures.
code_info:
Make an error message more explicit.
det_analysis:
Restrict import list to the needed modules.
*.m:
Import assoc_list.
instructions, and the last argument from local labels. All these were
placeholders for info put in there by prof.m and used when emitting C
code.
The set of labels that serve as return points are now calculated in llds.m
just before each procedure has its C code generated. This set is passed to
output_instruction along with the label at the start of the procedure.
*.m:
Changed the way the extra field in the label type is defined. Now
all labels are initially assumed to be 'unknown' and a seperate
profiling pass (to be implemented) will determine whether the label can
be accessed externally.
prog_io, hlds: Added the functor "multidet" to the type determinism.
Added types and predicates to relate determinism to its
two components, can_fail and soln_count.
Removed the functor "unspecified" from the type determinism,
substituting maybe(determinism) for determinism in proc_info.
Replaced the type category with the type code_model,
and added predicates to compute it from determinism.
det_analysis: Redone the analyses to work with determinism, not category
(or code_model). This should enable programmers to write
their own erroneous (and failure) predicates.
other files: Use the new and renamed types and access predicates.
compiler/*:
Add copyright messages.
Change all occurences of *.nl in comments to *.m.
compiler/mercury_compile.pp:
Change the output to the .dep files to use *.m rather than *.nl.
(NOTE: this means that `mmake' will not work any more if you
call your files *.nl!!!)
exprn_aux.nl:
a new module for manipulating rvals and lvals.
code_exprn.nl:
the new bottom level of the new code generator. This replaces
a large chunk of code_info.
*code* & *gen*:
various small changes to use the new bottom level of the
code generator.
io.nl:
Introduced a new predicate which ignore's any whitespace in the input.
Needs to have all the whitespace character's added to it.
*.nl and *.pp:
Changed the implementation of time profiling. Now during a compile,
the compiler identifies all the internal labels which can be accessed
externally, and marks them. At the moment, these are the continuation
labels of calls and the next disjunct in nondet disjunctions. Then
at the .mod output, it places a macro 'update_prof_current_proc' to
restore the profiling counter.
llds.nl:
Introduced an extra argument to the LLDS goto. It is the label
address of the Caller and is used for the profiling of tailcall's.
*.nl and *.pp:
Propagated the extra argument to all the appropiate files.
Makefile.common:
Add new targets `mercury_compile.sicstus' (the Mercury compiler
compiled with Sicstus) and `mercury_compile.sicstus.debug'
(debugging version of the above).
*.nl:
Use Sicstus-compatible char and string escapes.
Avoid the use of explicit existential quantification.
Various other hacks to get things to parse correctly under Sicstus.
prog_io.nl:
Don't allow (A -> B) in DCGs, since NU-Prolog and Mercury give
it different semantics to Sicstus.
sp_builtin.nl, sp_lib.nl:
Split sp_builtin.nl into sp_builtin.nl and sp_lib.nl.
sp_conv.sed:
Add sed script which converts some character escapes so that
they work with Sicstus.
term_io.nl:
Remove term_io__prefix_op etc. since they aren't used anymore.
now in dense_switch, string_switch and tag_switch, with the original
if-then-else implementation and the code that decides on optimizations
still in switch_gen.
Added options to replace the magic numbers governing the choice of switch
method.
Added comments to frameopt, jumpopt, labelopt and peephole.
