Estimated hours taken: 1.5
Split llds into two parts. llds.m defines the data types, while llds_out.m
has the predicates for printing the code.
Removed the call_closure instruction. Instead, we use calls to the
system-defined addresses do_call_{det,semidet,nondet}_closure. This is
how call_closure was implemented already. The advantage of the new
implementation is that it allows jump optimization of what used to be
call_closures, without new code in jumpopt.
Estimated hours taken: 3
options:
Add a new option, --branch-delay-slot, intended for use by mc on
the basis of the configuattion script. It says whether the machine
architecture has delays slots on branches.
The setting of option should affect whether we set
--optimize-delay-slots at -O2, but this doesn't work yet.
hlds_goal:
Add an extra field to hold follow_vars infromation to disjunctions,
switches and if-then-elses. I intend to use this information to
generate better code.
*.m:
Changes to accommodate the extra field.
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.
Estimated hours taken: 2
code_exprn:
When we are processing the flushing of create expressions, make sure
the Lval we are creating into isn't a field reference. This avoids
deep field of field of field of ... nesting. It does introduce
references to high register numbers, but this is a lesser evil,
and Tom and I plan to fix this anyway.
arg_info, globals, options:
Change --args old to --args simple.
options:
Make some help messages more specific.
code_aux, code_exprn, code_info, det_report, make_hlds, mercury_to_goedel,
prog_io, typecheck:
Changes to accommodate the move from varset__lookup_name
to varset__search_name.
Estimated hours taken: 1.5
Undo dylan's changes in the names of some library entities,
by applying the following sed script
s/term_atom/term__atom/g
s/term_string/term__string/g
s/term_integer/term__integer/g
s/term_float/term__float/g
s/term_context/term__context/g
s/term_functor/term__functor/g
s/term_variable/term__variable/g
s/_term__/_term_/g
s/std_util__bool_/bool__/g
to all the `.m' and `.pp' files in the compiler and library directories.
The reason for undoing these changes was to minimize incompatibilities
with 0.4 (and besides, the changes were not a really good idea in the first
place).
I also moved `bool' to a separate module.
The main reason for that change is to ensure that the `__' prefix is
only used when it genuinely represents a module qualifier.
(That's what dylan's changes were trying to acheive, but `term__'
does genuinely represent a module qualifier.)
compiler/*.m:
Apply sed script above;
where appropriate, add `bool' to the list of imported modules.
Estimated hours taken: 5
There was a problem where variables that die during forward
execution, and then become live again on backtracking were
not being handled correctly. There was some half-working code
to deal with the problem. It has now been fixed, and there
are some new test cases for the regression tests.
compiler/.cvsignore:
added *.ql since they become very irritating after a while...
compiler/inlining.m:
added a couple of comments
make a bit of the code more concise.
compiler/*.m:
changes to handle nondet-liveness correctly.
Estimated hours taken: _2___
Change names with badly placed double underscores (ie where the part of
a name before a double underscore is not the same as the module name.)
Reflect changes in the library interface.
compiler/*:
Use the newer, more correct form of the term and bool names.
Predicates "bool__" are now "std_util__bool" and labels of
the term ADT are now "term_" instead of "term__".
compiler/vn*.m:
change all names "vn__*" to a correct module prefix. All the
names remain qualified.
compiler/hlds.m:
s/\<is_builtin__/hlds__is_builtin_/g
s/\<dependency_info__/hlds__dependency_info_/g
compiler/unify_proc.m:
s/\<unify_proc_info__/unify_proc__info_/g
compiler/transform.m:
s/\<reschedule__conj/transform__reschedule_conj/g
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.
:- pragma(inline, predicate/arity).
This declaration means that the corresponding predicate will be inlined.
hlds.m: Add a field to the pred_info indicating whether or not to
inline the pred automatically.
make_hlds.m: Turn on the inline flag in the pred_info if there was a
pragma(inline, ...) declaration.
prog_io.m: Parse the new declaration.
mercury_to_mercury.m:
Spit out the new dec.
inlining.m: Inline the predicate if the inlining field is set in the
pred_info.
polymorphism.m:
code_aux.m: Add an extra paramater to calls to pred_info_init.
llds:
Optionally generate while (1) loops instead of short backward branches.
This is faster in the absence of fast jumps.
options:
Add a new option, --no-emit-c-loops.
middle_rec:
We now check if the LLDS code after the recursive call is empty.
If yes, we don't generate the downward loop.
code_aux:
Minor cleanup associated with previous change.
frameopt:
Instead of blindly assuming that any code before an if_val will be
able to fill the delay slot, we check whether it computes a value
that is used in the condition. We now also allow a slightly wider
range of user instructions to fill delay slots.
opt_util:
Some new preds to support the new funcionality in frameopt.
tag_switch:
Compute the tag of the switched-on value into a register at the
start, instead of computing it in each if_val.
frameopt:
Look inside blocks introduced by value numbering when looking
restorations of succip.
value_number, opt_util:
If we are using conservative garbage collection, disable value
numbering for blocks that allocate more than one cell on the heap.
This allows value numbering of most blocks to work in the absence
of -DALL_INTERIOR_POINTERS.
all other source files:
Clean up "blank" lines that nevertheless contain space or tab
characters.
-------------------------------------------------------
Implement unique modes. We do not handle local aliasing yet, so this
is still not very useful, except for io__state. Destructive update is
not yet implemented. Also note that this really only implements
"mostly unique" variables that may be non-unique on backtracking - we
don't check that you don't backtrack over I/O, for example.
prog_io.m, mode_util.m, modes.m, inst_match.m:
Major changes to Handle unique modes.
mercury_to_mercury.m, polymorphism.m, prog_out.m, undef_modes.m:
Use `ground(Uniqueness)' rather than just `ground'.
compiler/*.m:
Fix compile errors now that unique modes are enforced: add a
few calls to copy/2, and comment out lots of unique mode
declarations that caused problems.
typecheck.m, mode_info.m:
Hack around the use of unique modes, which doesn't work
because we don't allow local aliasing yet: make the insts
`uniq_type_info' and `uniq_mode_info' not unique at all,
and add a call to copy/2 when extracting the io_state from
type_info or mode_info.
-------------------------------------------------------
Plus a couple of unrelated changes:
hlds.m:
Change the modes for the special predicates from `ground -> ground'
to `in', so that any error messages that show those modes
come out looking nicer.
Add a new shared_inst_table for shared versions of user-defined
insts.
mercury_to_goedel.m:
Use string__is_alnum_or_underscore.
mercury_compile.pp llds.m:
fix occurences of A.B (use [A|B]) which were
causing problems trying to build a sicstus
compiler.
[the rest].m:
Fix the compiler so that calculator.m works.
This involved introducing an extra field into
the goal_info to keep track of variables that
become nondet-live.
context of the unification from which call was made. We we use this to generate
significantly better error messages. (There should be no more messages of the
form "call to __Unify__(blah blah blah) can fail".) Most of the files are
changed just to reflect this.
An unrelated change in det_analysis is that we now ensure the absence of
cycles by modifying the new inferred determinism in the light of the old
one, ensuring that any changes are monotonic.
In hlds_out, inhibit the printing of pseudo-imported predicates (unifications)
since nobody cares about them except sometimes Fergus.
code_gen.pp:
Put the comment about the contents of stack slots before the initial
label, since this way it will be preserved by optimizations.
cse_detection.m:
Extended the search to look for cses in if-then-elses and switches
as well as disjunctions. Removed InstmapDelta from preds in which it
was not being used.
det_analysis.m:
Make the diagnosis routines more robust. The changes here avoid the
Philip's problems with lexical.m.
jumpopt.m:
Minor formatting changes.
livemap.m:
Avoid duplicating livevals instructions when optimizations are
repeated, since this can confuse some optimizations.
llds.m:
Minor documentation change.
make_hlds.m:
Minor formatting change.
mercury_compile.pp:
Do not map arguments to registers if any semantic errors have been
found.
middle_rec.m and code_aux.m:
Apply middle recursion only if tail recursion is not possible,
since tail recursion yields more efficient code.
opt_util.m:
Added a predicate to recognize constant conditions in if_vals.
Modified a predicate to make it better suited for frameopt.
optimize.pp:
Changed the way optimizations were repeated to allow better control.
Repeat peephole once more after frameopt, since the new frameopt
can benefit from this.
options.m:
Removed the --compile-to-c option, which was obsolete. Added an
option for predicate-wide value numbering, which is off by default.
Changed some of the default values of optimization flags to reduce
compilation time while holding the loss of speed of generated code
to a minimum.
peephole.m:
Look for if_vals whose conditions are constants, and eliminate the
if_val or turn it into a goto depending on the value of the constant.
Generalized the condition for optimizing incr_sp/decr_sp pairs.
value_number.m:
Added a prepass to separate primary tag tests in if-then-elses from
the test of the secondary tag, which requires dereferencing the
pointer.
Added sanity check routines to test two aspects of the generated code.
First, whether it produces the same values for the live variables as
the original code, and second, whether it has moved any dereferences
of a pointer before a test of the tag of that pointer. If either test
fails, we use the old instruction sequence.
vn_debug.m:
New messages to announce the failure of the sanity checks. They are
enabled by default, but of course can only appear if value numbering
is turned on (it is still off by default).
vn_flush.m:
Threaded a list of forbidden lvals (lvals that may not be assigned to)
through the flushing routines. When saving the old value of an lval
that is being assigned to, we use this list to avoid modifying any of
the values used on the right hand side of the assignment, even if the
saving of an old value results in assignment that requires another
save, and so on recursively.
When the flushing of a node_lval referred to a shared vn, the uses of
the access vns of the node_lvals were not being adjusted properly.
Now they are.
vn_order.m:
The ctrl_vn phase of the ordering was designed to ensure that all
nodes that need not come before a control node come after it. However,
nodes were created after this phase operated, causing leakage of some
value nodes in front of control nodes. Some of these led to pointer
dereferences before tag tests, causing bus errors. The ctrl_vn phase
is now last to avoid this problem.
vn_table.m:
Added an extra interface predicate to support the sanity checks in
value_number.
vn_util.m:
The transformation of c1-e2 into (0-e2)+c1 during vnrval simplification
could lead to an infinite loop in the compiler if c1 was zero. A test
for this case now prevents the loop.
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.
unify_gen:
Whenever we do a test of a variable against a non-constant functor,
we now try to turn it into a negated test on a constant functor.
This is possible if these two functors are the only ones.
code_aux:
Added an extra predicate to look up type definitions to make the
previous change easier.
llds, code_gen, opt_util, opt_debug, frameopt, jumpopt, peephole:
Added a boolean argument to do_succeed to say whether the nondet
frame should be discarded on success or not. The default is no,
but peephole has an optimization that tries to turn on this flag.
optimize, value_number, vn*:
Restructured the top level of value numbering as part of an effort
to identify blocks that could be optimized further given our knowledge
that the contents of e.g. stackvars is also in registers when we
jump to those blocks. Redone the interface between value_number and
frameopt to allow value_number to be iterated, which is necessary
to take advantage of the previously mentioned capability. Threated
the I/O state through the relevant predicates; value numbering doesn't
use non-logical I/O any more.
think I have forgotten ;-)
live_vars.nl:
Fixed the stackslot sharing problem.
Still need to fix the instmap problem.
code_*.nl:
Bits and pieces of higher order stuff, threading the
instmap through code generation.
hlds_out.nl:
Write out the stack allocations (with var numbers).
*.nl:
Replace all occurrences of `not(Vars, Goal)' with just
plain `not(Goal)'.
type_util.nl, switch_gen.nl:
Higher-order pred types are not user-defined types.
Add a `predtype' type category for them.
call_gen.nl:
Change call_closure/2 to call_closure/3 (with liveinfo).
Plus a little bit of random hacking.
inlining.nl:
make the heuristic for inlining stricter.
mercury_compile.*:
add an extra garbage collection.
code_aux.*:
add "goal_is_flat" test predicate.
middle_rec:
code to do middle recursion optimization.
code_aux:
new auxiliary module that unlike code_util, does import code_info.
Previous change to peephole and opt_util was implementation of chain rules.
