Estimated hours taken: 70
Branches: main
Implement the trace goal construct we discussed, for now for the LLDS backends
only.
Since the syntax of trace goals is non-trivial, useful feedback on syntax
errors inside trace goal attributes is essential. With the previous setup, this
wasn't possible, since the code that turned terms into parse tree goals turned
*all* terms into goals; it couldn't recognize any errors, sweeping them under
the rug as calls. This diff changes that. Now, if this code recognizes a
keyword that indicates a particular construct, it insists on the rest of the
code following the syntax required for that construct, and returns error
messages if it doesn't.
We handle the trace goal attributes that specify state variables to be threaded
through the trace goal (either the I/O state or a mutable variable) in
add_clause.m, at the point at which we transform the list of items to the HLDS.
We handle the compile-time condition on trace goals in the invocation of
simplify at the end of semantics analysis, by eliminating the goal if the
compile-time condition isn't met. We handle run-time conditions on trace goals
partially in the same invocation of simplify: we transform trace goals with
runtime conditions into an if-then-else with the trace goal as the then part
and `true' as the else part, the condition being a foreign_proc that is handled
specially by the code generator, that special handling being to replace
the actual code of the foreign_proc (which is a dummy) with the evaluation of
the runtime condition.
Since these changes require significant changes to some of our key data
structures, I took the liberty of doing some renaming of function symbols
at the same time to avoid using ambiguities with respect to language keywords.
library/ops.m:
Add "trace" as an operator.
compiler/prog_data.m:
Define data types to represent the various attributes of trace goals.
Rename some function symbols to avoid ambiguities.
compiler/prog_item.m:
Extend the parse tree representation of goals with a trace goal.
compiler/mercury_to_mercury.m:
Output the new kind of goal and its components.
compiler/hlds_goal.m:
Extend the HLDS representation of scopes with a scope_reason
representing trace goals.
Add a mechanism (an extra argument in foreign_procs) to allow
the representation of goals that evaluate runtime trace conditions.
Since this requires modifying all code that traverses the HLDS,
do some renames that were long overdue: rename not as negation,
rename call as plain_call, and rename foreign_proc as
call_foreign_proc. These renames all avoid using language keywords
as function symbols.
Change the way we record goals' purities. Instead of optional features
to indicate impure or semipure, which is error-prone, use a plain
field in the goal_info, accessed in the usual way.
Add a way to represent that a goal contains a trace goal, and should
therefore be treated as if it were impure when considering whether to
optimize it away.
Reformat some comments describing function symbols.
compiler/hlds_out.m:
Output the new construct in the HLDS.
compiler/prog_io_util.m:
Generalize the maybe[123] types to allow the representation of more
than one error message. Add functions to extract the error messages.
Add a maybe4 type. Rename the function symbols of these types to
avoid massive ambiguity.
Change the order of some predicates to bring related predicates
next to each other.
compiler/prog_io.m:
compiler/prog_io_dcg.m:
compiler/prog_io_goal.m:
compiler/prog_io_pragma.m:
Rework these modules almost completely to find and accumulate syntax
errors as terms are being parsed. In some cases, this allowed us to
replace "XXX this is a hack" markers with meaningful error-reporting
code.
In prog_io_goal.m, add code for parsing trace goals.
In a bunch of places, update obsolete coding practices, such as using
nested chains of closures instead of simple sequential code, and
using A0 and A to refer to values of different types (terms and goals
respectively). Use more meaningful variable names.
Break up some too-large predicates.
compiler/superhomogeneous.m:
Find and accumulate syntax errors as terms are being parsed.
compiler/add_clause.m:
Add code to transform trace goals from the parse tree to the HLDS.
This is where the IO state and mutable variable attributes of trace
goals are handled.
Eliminate the practice of using the naming scheme Body0 and Body
to refer to values of different types (prog_item.goal and hlds_goal
respectively).
Use error_util for some error messages.
library/private_builtin.m:
Add the predicates referred to by the transformation in add_clause.m.
compiler/goal_util.m:
Rename a predicate to avoid ambiguity.
compiler/typecheck.m:
Do not print error messages about missing clauses if some errors have
been detected previously.
compiler/purity.m:
Instead of just computing purity, compute (and record) also whether
a goal contains a trace goal. However, treat trace goals as pure.
compiler/mode_info.m:
Add trace goals as a reason for locking variables.
Rename some function symbols to avoid ambiguity.
compiler/modes.m:
When analyzing trace goal scopes, lock the scope's nonlocal variables
to prevent them from being further instantiated.
compiler/det_analysis.m:
Insist on the code in trace goal scopes being det or cc_multi.
compiler/det_report.m:
Generate the error message if the code in a trace goal scope isn't det
or cc_multi.
compiler/simplify.m:
At the end of the front end, eliminate trace goal scopes if their
compile-time condition is false. Transform trace goals with runtime
conditions as described at the top.
Treat goals that contain trace goals as if they were impure when
considering whether to optimize them away.
compiler/mercury_compile.m:
Tell simplify when it is being invoked at the end of the front end.
Rename a predicate to avoid ambiguity.
compiler/trace_params.m:
Provide the predicates simplify.m need to be able to evaluate the trace
goal conditions regarding trace levels.
compiler/trace.m:
compiler/trace_gen.m:
Rename the trace module as trace_gen, since "trace" is now an operator.
Rename some predicates exported by the module, now that it is no longer
possible to preface calls with "trace." as a module qualifier.
compiler/notes/compiler_design.html:
Document this name change.
compiler/options.m:
Rename the trace option as trace_level internally, since "trace"
is now an operator. The user-visible name remains the same.
Add the new --trace-flag option.
Delete an obsolete option.
compiler/handle_options.m:
Rename the function symbols of the grade_component type,
since "trace" is now an operator.
compiler/llds.m:
Extend the LLDS with a mechanism to refer to C global variables.
For now, these are used to refer to C globals that will be created
by mkinit to represent the initial values of the environment variables
referred to by trace goals.
compiler/commit_gen.m:
Check that no trace goal with a runtime condition survives to code
generation; they should have been transformed by simplify.m.
compiler/code_gen.m:
Tell commit_gen.m what kind of scope it is generating code for.
compiler/pragma_c_gen.m:
Generate code for runtime conditions when handling the foreign_procs
created by simplify.m.
compiler/code_info.m:
Allow pragma_c_gen.m to record what environment variables it has
generated references to.
compiler/proc_gen.m:
Record the set of environment variables a procedure refers to
in the LLDS procedure header, for efficient access by llds_out.m.
compiler/llds_out.m:
Handle the new LLDS construct, and tell mkinit which environment
variables need C globals created for them.
compiler/pd_util.m:
Rename some predicates to avoid ambiguity.
compiler/*.m:
Conform to the changes above, mainly the renames of function symbols
and predicates, the changed signatures of some predicates, and the new
handling of purity.
util/mkinit.c:
Generate the definitions and the initializations of any C globals
representing the initial status (set or not set) of environment
variables needed by trace goals.
library/assoc_list.m:
Add some predicates that are useful in prog_io*.m.
library/term_io.m:
Minor cleanup.
tests/hard_coded/trace_goal_{1,2}.{m,exp}:
New test cases to test the new construct, identical except for whether
the trace goal is enabled at compile time.
tests/hard_coded/trace_goal_env_{1,2}.{m,exp}:
New test cases to test the new construct, identical except for whether
the trace goal is enabled at run time.
tests/hard_coded/Mercury.options:
tests/hard_coded/Mmakefile:
Enable the new test cases.
tests/invalid/*.err_exp:
Update the expected output for the new versions of the error messages
now being generated.
Estimated hours taken: 18
Branches: main
Move the univ, maybe, pair and unit types from std_util into their own
modules. std_util still contains the general purpose higher-order programming
constructs.
library/std_util.m:
Move univ, maybe, pair and unit (plus any other related types
and procedures) into their own modules.
library/maybe.m:
New module. This contains the maybe and maybe_error types and
the associated procedures.
library/pair.m:
New module. This contains the pair type and associated procedures.
library/unit.m:
New module. This contains the types unit/0 and unit/1.
library/univ.m:
New module. This contains the univ type and associated procedures.
library/library.m:
Add the new modules.
library/private_builtin.m:
Update the declaration of the type_ctor_info struct for univ.
runtime/mercury.h:
Update the declaration for the type_ctor_info struct for univ.
runtime/mercury_mcpp.h:
runtime/mercury_hlc_types.h:
Update the definition of MR_Univ.
runtime/mercury_init.h:
Fix a comment: ML_type_name is now exported from type_desc.m.
compiler/mlds_to_il.m:
Update the the name of the module that defines univs (which are
handled specially by the il code generator.)
library/*.m:
compiler/*.m:
browser/*.m:
mdbcomp/*.m:
profiler/*.m:
deep_profiler/*.m:
Conform to the above changes. Import the new modules where they
are needed; don't import std_util where it isn't needed.
Fix formatting in lots of modules. Delete duplicate module
imports.
tests/*:
Update the test suite to confrom to the above changes.
Estimated hours taken: 6
Branches: main
compiler/*.m:
Convert almost all the compiler modules to use . instead of __ as
the module qualifier.
In some cases, change the names of predicates and types to make them
meaningful without the module qualifier. In particular, most of the
types that used to be referred to with an "mlds__" prefix have been
changed to have a "mlds_" prefix instead of changing the prefix to
"mlds.".
There are no algorithmic changes.
Estimated hours taken: 4
Branches: main
Various cleanups for the modules in the compiler directory. The are
no changes to algorithms except the replacement of some if-then-elses
that would naturally be switches with switches and the replacement of
most of the calls to error/1.
compiler/*.m:
Convert calls to error/1 to calls to unexpected/2 or sorry/2 as
appropriate throughout most or the compiler.
Fix inaccurate assertion failure messages, e.g. identifying the
assertion failure as taking place in the wrong module.
Add :- end_module declarations.
Fix formatting problems and bring the positioning of comments
into line with our current coding standards.
Fix some overlong lines.
Convert some more modules to 4-space indentation. Fix some spots
where previous conversions to 4-space indentation have stuffed
the formatting of the code up.
Fix a bunch of typos in comments.
Use state variables in more places; use library predicates
from the sv* modules where appropriate.
Delete unnecessary and duplicate module imports.
Misc. other small cleanups.
Estimated hours taken: 5
Branches: main
Implement trail usage optimization for the lowlevel backend.
compiler/code_gen.m:
As we generate code for each HLDS goal check if it is safe to omit
trailing operations. Do so, if trail usage optimization is enabled.
Reformat some code for the purposes of readability.
compiler/commit_gen.m:
compiler/disj_gen.m:
compiler/ite_gen.m:
compiler/code_info.m:
Thread the above information down to the relevant parts of the code
generator.
Misc. cleanups: reduce unnecessary module qualification and minor
layout fixes.
compiler/code_util.m:
Add a utility predicate the tests if we are allowed to omit trailing
primitives for a given HLDS goal.
compiler/llds.m:
Add the equivalence type: add_trail_ops == bool.
compiler/hlds_goal.m:
compiler/prog_data.m:
Unrelated changes: fix typos in comments.
Add an end_module declaration to the former.
Estimated hours taken: 8
Branches: main
Improve the error messages generated for determinism errors involving committed
choice contexts. Previously, we printed a message to the effect that e.g.
a cc pred is called in context that requires all solutions, but we didn't say
*why* the context requires all solutions. We now keep track of all the goals
to the right that could fail, since it is these goals that may reject the first
solution of a committed choice goal.
The motivation for this diff was the fact that I found that locating the
failing goal can be very difficult if the conjunction to the right is
a couple of hundred lines long. This would have been a nontrivial problem,
since (a) unifications involving values of user-defined types are committed
choice goals, and (b) we can expect uses of user-defined types to increase.
compiler/det_analysis.m:
Keep track of goals to the right of the current goal that could fail,
and include them in the error representation if required.
compiler/det_report.m:
Include the list of failing goals to the right in the representations
of determinism errors involving committed committed choice goals.
Convert the last part of this module that wasn't using error_util
to use error_util. Make most parts of this module just construct
error message specifications; print those specifications (using
error_util) in only a few places.
compiler/hlds_out.m:
Add a function for use by the new code in det_report.m.
compiler/error_util.m:
Add a function for use by the new code in det_report.m.
compiler/error_util.m:
compiler/compiler_util.m:
Error_util is still changing reasonably often, and yet it is
included in lots of modules, most of which need only a few simple
non-parse-tree-related predicates from it (e.g. unexpected).
Move those predicates to a new module, compiler_util.m. This also
eliminates some undesirable dependencies from libs to parse_tree.
compiler/libs.m:
Include compiler_util.m.
compiler/notes/compiler_design.html:
Document compiler_util.m, and fix the documentation of some other
modules.
compiler/*.m:
Import compiler_util instead of or in addition to error_util.
To make this easier, consistently use . instead of __ for module
qualifying module names.
tests/invalid/det_errors_cc.{m,err_exp}:
Add this new test case to test the error messages for cc contexts.
tests/invalid/det_errors_deet.{m,err_exp}:
Add this new test case to test the error messages for unifications
inside function symbols.
tests/invalid/Mmakefile:
Add the new test cases.
tests/invalid/det_errors.err_exp:
tests/invalid/magicbox.err_exp:
Change the expected output to conform to the change in det_report.m,
which is now more consistent.
Estimated hours taken: 4
Branches: main
compiler/*.m:
Convert a bunch of modules to four-space indentation.
In the process, fix departures from our coding standards.
In some cases, do minor other cleanups such as changing argument orders
to be friendly to state variables.
There are no algorithmic changes.
Estimated hours taken: 3
Branches: main
compiler/*.m:
Import only one module per line in the modules of the compiler
where my previous diff did not already do so.
Misc other cleanups.
Where relevant, use the new mechanism in tree.m.
compiler/tree.m:
Fix a performance problem I noticed while update :- import_module
items. Instead of supplying a function to convert lists of trees
to a tree, make the tree data structure able to hold a list of
subtrees directly. This reduces the number of times where we have to
convert list of trees to trees that are sticks just to stay within
the old definition of what a tree is.
Estimated hours taken: 4
Branches: main
Reduce the dependence of earlier parts of the compiler on the later ones.
Unnecessary import_module declarations in top level modules such as hlds.m
cause unnecessary recompilations when adding new types in later modules,
such as submodules of ll_backend.m. This change reduces the number of such
unnecessary imports.
There are no changes in algorithms, only functionality being moved around.
compiler/code_model.m:
Change this module from being a submodule of backend_libs.m to being a
submodule of hlds.m, since nothing in it is dependent on any backend.
compiler/arg_info.m:
compiler/code_util.m:
Change arg_info.m from being a submodule of ll_backend.m to being a
submodule of hlds.m, since most of it is applicable to all current
and foreseeable backends. Move the one exported predicate that is
ll_backend dependent, and its support predicates, to code_util.m.
compiler/backend_libs.m:
compiler/ll_backend.m:
compiler/hlds.m:
Update include_module declarations in accordance with the above.
compiler/prog_data.m:
compiler/term_util.m:
Instead of defining two separate types for holding argument size and
termination information, one including HLDS-specific information (in
term_util.m) and one not (in prog_data.m), use a polymorphic type
defined in prog_data.m and two monomorphic instances.
compiler/termination.m:
compiler/mercury_to_mercury.m:
Change the predicates for writing out argument size and termination
information to handle the polymorphic type (we don't need special
handling of the monomorphic versions), and move them from termination.m
to mercury_to_mercury.m, since this allows us to avoid some
undesirable dependencies.
compiler/base_typeclass_info.m:
compiler/hlds_code_util.m:
Move the predicate make_instance_string from base_typeclass_info.m
to hlds_code_util.m, again because it allows us to remove some
undesirable dependencies.
compiler/top_level.m:
compiler/backend_libs.m:
compiler/check_hlds.m:
compiler/hlds.m:
compiler/ll_backend.m:
compiler/parse_tree.m:
compiler/transform_hlds.m:
Delete some import_module declarations of other top level modules
in these top level modules. Some imports were totally unnecessary.
Some imports were useful in only a small minority of submodules;
those submodules now import the necessary top level modules directly.
Move remaining import_module declarations to the implementation section
where this is feasible.
Where we still need to import modules we ideally shouldn't, note why.
compiler/*.m:
Update imports of code_util and arg_info.
In some cases, import top level modules no longer imported by the
parent module.
In some cases, delete unnecessary imports.
Estimated hours taken: 2
Branches: main
compiler/*.m:
Import only one compiler module per line. Sort the blocks of imports.
This makes it easier to merge in changes.
In a couple of places, remove unnecessary imports.
The main aim of this change is to make the overall, high-level structure
of the compiler clearer, and to encourage better encapsulation of the
major components.
compiler/libs.m:
compiler/backend_libs.m:
compiler/parse_tree.m:
compiler/hlds.m:
compiler/check_hlds.m:
compiler/transform_hlds.m:
compiler/bytecode_backend.m:
compiler/aditi_backend.m:
compiler/ml_backend.m:
compiler/ll_backend.m:
compiler/top_level.m:
New files. One module for each of the major components of the
Mercury compiler. These modules contain (as separate sub-modules)
all the other modules in the Mercury compiler, except gcc.m and
mlds_to_gcc.m.
Mmakefile:
compiler/Mmakefile:
Handle the fact that the top-level module is now `top_level',
not `mercury_compile' (since `mercury_compile' is a sub-module
of `top_level').
compiler/Mmakefile:
Update settings of *FLAGS-<modulename> to use the appropriate
nested module names.
compiler/recompilation_check.m:
compiler/recompilation_version.m:
compiler/recompilation_usage.m:
compiler/recompilation.check.m:
compiler/recompilation.version.m:
compiler/recompilation.version.m:
Convert the `recompilation_*' modules into sub-modules of the
`recompilation' module.
compiler/*.m:
compiler/*.pp:
Module-qualify the module names in `:- module', `:- import_module',
and `:- use_module' declarations.
compiler/base_type_info.m:
compiler/base_type_layout.m:
Deleted these unused empty modules.
compiler/prog_data.m:
compiler/globals.m:
Move the `foreign_language' type from prog_data to globals.
compiler/mlds.m:
compiler/ml_util.m:
compiler/mlds_to_il.m:
Import `globals', for `foreign_language'.
Mmake.common.in:
trace/Mmakefile:
runtime/Mmakefile:
Rename the %.check.c targets as %.check_hdr.c,
to avoid conflicts with compiler/recompilation.check.c.
Estimated hours taken: 6
Eliminated a lot of the dependencies on the the `code_model' type,
and move that type from llds.m into a new module `code_model'.
The aim of this change is to improve the modularity of the compiler by
reducing the number of places in the compiler front-end that depend
on back-end concepts and the number of places in the MLDS back-end
which depend on the LLDS.
compiler/code_model.m:
New module. Contains the code_model type and associated
procedures.
compiler/llds.m:
Move the code_model type into code_model.m.
compiler/hlds_goal.m:
Move the goal_info_get_code_model procedure into code_model.m,
to avoid having the HLDS modules import code_model.
compiler/hlds_out.m:
Delete `hlds_out__write_code_model', since it wasn't being used.
compiler/hlds_pred.m:
Move the proc_info_interface_code_model procedure into code_model.m,
to avoid having the HLDS modules import code_model.
compiler/goal_path.m:
When computing the `maybe_cut' field for `some' goals,
compute it by comparing the determinism rather than by
comparing the goal_infos.
compiler/unique_modes.m:
Use determinism and test for soln_count = at_most_many
rather than using code_model and testing for model_non.
compiler/inlining.m:
Test for determinism nondet/multi rather than testing
for code_model model_non.
compiler/hlds_pred.m:
compiler/det_report.m:
Change valid_code_model_for_eval_method, which succeeded unless
the eval_method was minimal_model and the code_model was model_det,
to valid_determinism_for_eval_method, which succeeds unless the
eval_method is minimal_model and the determinism cannot fail.
As well as avoiding a dependency on code_model in the HLDS
modules, this also fixes a bug where det_report could give
misleading error messages, saying that `multi' was a valid
determinism for `minimal_model' predicates, when in fact the
compiler will always report a determinism error if you declare
a `minimal_model' predicate with determinism `multi'.
(Actually the code in which this bug occurs is in fact
unreachable, but this is no doubt also a bug... I'll address
that one in a separate change.)
compiler/lookup_switch.m:
Simplify the code a bit by using globals__lookup_*_option
rather than globals__get_option and then getopt__lookup_option.
compiler/*.m:
Add `import_module' declarations for `code_model', and in some
cases remove `import_module' declarations for `llds'.
Estimated hours taken: 0.01
compiler/commit_gen.m:
A new file containing the code tyhat generates code for commits.
It was left out my previous checkin.
