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mercury/compiler/code_gen.m
Simon Taylor 18430aaef1 Aditi compilation. 
Estimated hours taken: 1200

Aditi compilation.

compiler/options.m:
	The documentation for these is commented out because the Aditi
	system is not currently useful to the general public.
	--aditi: enable Aditi compilation.
	--dump-rl: write the intermediate RL to `<module>.rl_dump'.
	--dump-rl-bytecode: write a text version of the bytecodes
		to `<module>.rla'
	--aditi-only: don't produce a `.c' file.
	--filenames-from-stdin: accept a list of filenames to compile
		from stdin. This is used by the query shell.
	--optimize-rl, --optimize-rl-cse, --optimize-rl-invariants,
	--optimize-rl-index, --detect-rl-streams:
		Options to control RL optimization passes.
	--aditi-user:
		Default owner of any Aditi procedures,
		defaults to $USER or "guest".
	--generate-schemas:
		write schemas for base relations to `<module>'.base_schema
		and schemas for derived relations to `<module>'.derived_schema.
		This is used by the query shell.

compiler/handle_options.m:
	Handle the default for --aditi-user.

compiler/hlds_pred.m:
compiler/prog_data.m:
compiler/prog_io_pragma.m:
compiler/make_hlds.m:
	Add some Aditi pragma declarations - `aditi', `supp_magic', `context',
	`naive', `psn' (predicate semi-naive), `aditi_memo', `aditi_no_memo',
	`base_relation', `owner' and `index'.
	Separate out code to parse a predicate name and arity.

compiler/hlds_pred.m:
	Add predicates to identify Aditi procedures.
	Added markers `generate_inline' and `aditi_interface', which
	are used internally for Aditi code generation.
	Add an `owner' field to pred_infos, which is used for database
	security checks.
	Add a field to pred_infos to hold the list of indexes for a base
	relation.

compiler/make_hlds.m:
	Some pragmas must be exported if the corresponding predicates
	are exported, check this.
	Make sure stratification of Aditi procedures is checked.
	Predicates with a mode declaration but no type declaration
	are no longer assumed to be local.
	Set the `do_aditi_compilation' field of the module_info if there
	are any local Aditi procedures or base relations.
	Check that `--aditi' is set if Aditi compilation is required.

compiler/post_typecheck.m:
	Check that every Aditi predicate has an `aditi__state' argument,
	which is used to ensure sequencing of updates and that Aditi
	procedures are only called within transactions.

compiler/dnf.m:
	Changed the definition of disjunctive normal form slightly
	so that a call followed by some atomic goals not including
	any database calls is considered atomic. magic.m can handle
	this kind of goal, and it results in more efficient RL code.

compiler/hlds_module.m:
compiler/dependency_graph.m:
	Added dependency_graph__get_scc_entry_points which finds
	the procedures in an SCC which could be called from outside.
	Added a new field to the dependency_info, the
	aditi_dependency_ordering. This contains all Aditi SCCs of
	the original program, with multiple SCCs merged where
	possible to improve the effectiveness of differential evaluation
	and the low level RL optimizations.

compiler/hlds_module.m:
	Add a field to record whether there are any local Aditi procedures
	in the current module.
	Added versions of module_info_pred_proc_info and
	module_info_set_pred_proc_info which take a pred_proc_id,
	not a separate pred_id and proc_id.

compiler/polymorphism.m:
compiler/lambda.m:
	Make sure that predicates created for closures in Aditi procedures
	have the correct markers.

compiler/goal_util.m:
	Added goal_util__switch_to_disjunction,
	goal_util__case_to_disjunct (factored out from simplify.m)
	and goal_util__if_then_else_to_disjunction. These are
	require because supplementary magic sets can't handle
	if-then-elses or switches.

compiler/type_util.m:
	Added type_is_aditi_state/1.

compiler/mode_util.m:
	Added partition_args/5 which partitions a list of arguments
	into inputs and others.

compiler/inlining.m:
	Don't inline memoed procedures.
	Don't inline Aditi procedures into non-Aditi procedures.

compiler/intermod.m:
	Handle Aditi markers.
	Clean up handling of markers which should not appear in `.opt' files.

compiler/simplify.m:
	Export a slightly different interface for use by magic.m.
	Remove explicit quantifications where possible.
	Merge multiple nested quantifications.
	Don't report infinite recursion warnings for Aditi procedures.

compiler/prog_out.m:
	Generalised the code to output a module list to write any list.

compiler/code_gen.m:
compiler/arg_info.m:
	Don't process Aditi procedures.

compiler/mercury_compile.m:
	Call magic.m and rl_gen.m.
	Don't perform the low-level annotation passes on Aditi procedures.
	Remove calls to constraint.m - sometime soon a rewritten version
	will be called directly from deforestation.

compiler/passes_aux.m:
	Add predicates to process only non-Aditi procedures.

compiler/llds.m:
compiler/llds_out.m:
	Added new `code_addr' enum members, do_{det,semidet,nondet}_aditi_call,
	which are defined in extras/aditi/aditi.m.

compiler/call_gen.m:
	Handle generation of do_*_aditi_call.

compiler/llds_out.m:
	Write the RL code for the module as a constant char array
	in the `.c' file.

compiler/term_errors.m:
compiler/error_util.m:
	Move code to describe predicates into error_util.m
	Allow the caller to explicitly add line breaks.
	Added error_util:list_to_pieces to format a list of
	strings.
	Reordered some arguments for currying.

compiler/hlds_out.m:
	Don't try to print clauses if there are none.

runtime/mercury_init.h:
util/mkinit.c:
scripts/c2init.in:
	Added a function `mercury__load_aditi_rl_code()' to the generated
	`<module>_init.c' file which throws all the RL code for the program
	at the database. This should be called at connection time by
	`aditi__connect'.
	Added an option `--aditi' which controls the output
	`mercury__load_aditi_rl_code()'.

compiler/notes/compiler_design.html:
	Document the new files.

Mmakefile:
bindist/Mmakefile:
	Don't distribute extras/aditi yet.

New files:

compiler/magic.m:
compiler/magic_util.m:
	Supplementary magic sets transformation. Report errors
	for constructs that Aditi can't handle.

compiler/context.m:
	Supplementary context transformation.

compiler/rl_gen.m:
compiler/rl_relops.m:
	Aditi code generation.

compiler/rl_info.m:
	Code generator state.

compiler/rl.m:
	Intermediate RL representation.

compiler/rl_util:
	Predicates to collect information about RL instructions.

compiler/rl_dump.m:
	Print out the representation in rl.m.

compiler/rl_opt.m:
	Control low-level RL optimizations.

compiler/rl_block.m:
	Break a procedure into basic blocks.

compiler/rl_analyse.m:
	Generic dataflow analysis for RL procedures.

compiler/rl_liveness.m:
	Make sure all relations are initialised before used, clear
	references to relations that are no longer required.

compiler/rl_loop.m:
	Loop invariant removal.

compiler/rl_block_opt.m:
	CSE and instruction merging on basic blocks.

compiler/rl_key.m:
	Detect upper/lower bounds for which a goal could succeed.

compiler/rl_sort.m:
	Use indexing for joins and projections.
	Optimize away unnecessary sorting and indexing.

compiler/rl_stream.m:
	Detect relations which don't need to be materialised.

compiler/rl_code.m:
	RL bytecode definitions. Automatically generated from the Aditi
	header files.

compiler/rl_out.m:
compiler/rl_file.m:
	Output the RL bytecodes in binary to <module>.rlo (for use by Aditi)
	and in text to <module>.rla (for use by the RL interpreter).
	Also output the schema information if --generate-schemas is set.

compiler/rl_exprn.m:
	Generate bytecodes for join conditions.

extras/aditi/Mmakefile:
extras/aditi/aditi.m:
	Definitions of some Aditi library predicates and the
	interfacing and transaction processing code.
1998-12-06 23:49:14 +00:00

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%---------------------------------------------------------------------------%
% Copyright (C) 1994-1998 The University of Melbourne.
% This file may only be copied under the terms of the GNU General
% Public License - see the file COPYING in the Mercury distribution.
%---------------------------------------------------------------------------%
%
% Code generation - convert from HLDS to LLDS.
%
% Main authors: conway, zs.
%
% The two main tasks of this module are
%
% 1 to look after the aspects of generating code for a procedure
% that do not involve generating code for a specific goal, and
%
% 2 to provide a generic predicate that can be called from anywhere in
% the code generator to generate code for a goal.
%
% Code_gen forwards most of the actual construction of code for particular
% goals to other modules. The generation of code for unifications is done
% by unify_gen, for calls, higher-order calls and method calls by call_gen,
% for commits by commit_gen, for if-then-elses and negations by ite_gen,
% for switches by switch_gen and its subsidiary modules, for disjunctions
% by disj_gen, and for pragma_c_codes by pragma_c_gen. The only kind of goal
% handled directly by code_gen is the conjunction.
%
%---------------------------------------------------------------------------%
:- module code_gen.
:- interface.
:- import_module hlds_module, hlds_pred, hlds_goal, llds, code_info.
:- import_module globals.
:- import_module list, io.
% Translate a HLDS module to LLDS.
:- pred generate_code(module_info::in, module_info::out,
list(c_procedure)::out, io__state::di, io__state::uo) is det.
% Translate a HLDS procedure to LLDS, threading through
% the data structure that records information about layout
% structures and the counter for ensuring the uniqueness
% of cell numbers.
:- pred generate_proc_code(pred_info::in, proc_info::in,
proc_id::in, pred_id::in, module_info::in, globals::in,
global_data::in, global_data::out, int::in, int::out,
c_procedure::out) is det.
% Translate a HLDS goal to LLDS.
:- pred code_gen__generate_goal(code_model::in, hlds_goal::in, code_tree::out,
code_info::in, code_info::out) is det.
%---------------------------------------------------------------------------%
%---------------------------------------------------------------------------%
:- implementation.
:- import_module call_gen, unify_gen, ite_gen, switch_gen, disj_gen.
:- import_module par_conj_gen, pragma_c_gen, commit_gen.
:- import_module continuation_info, trace, options, hlds_out.
:- import_module code_aux, middle_rec, passes_aux, llds_out.
:- import_module code_util, type_util, mode_util.
:- import_module prog_data, prog_out, instmap.
:- import_module bool, char, int, string.
:- import_module map, assoc_list, set, term, tree, std_util, require, varset.
%---------------------------------------------------------------------------%
generate_code(ModuleInfo0, ModuleInfo, Procedures) -->
% get a list of all the predicate ids
% for which we are going to generate code.
{ module_info_predids(ModuleInfo0, PredIds) },
% now generate the code for each predicate
generate_pred_list_code(ModuleInfo0, ModuleInfo, PredIds, Procedures).
% Translate a list of HLDS predicates to LLDS.
:- pred generate_pred_list_code(module_info::in, module_info::out,
list(pred_id)::in, list(c_procedure)::out,
io__state::di, io__state::uo) is det.
generate_pred_list_code(ModuleInfo, ModuleInfo, [], []) --> [].
generate_pred_list_code(ModuleInfo0, ModuleInfo, [PredId | PredIds],
Predicates) -->
{ module_info_preds(ModuleInfo0, PredInfos) },
% get the pred_info structure for this predicate
{ map__lookup(PredInfos, PredId, PredInfo) },
% extract a list of all the procedure ids for this
% predicate and generate code for them
{ pred_info_non_imported_procids(PredInfo, ProcIds) },
(
{ ProcIds = []
; hlds_pred__pred_info_is_aditi_relation(PredInfo)
}
->
{ Predicates0 = [] },
{ ModuleInfo1 = ModuleInfo0 }
;
generate_pred_code(ModuleInfo0, ModuleInfo1, PredId,
PredInfo, ProcIds, Predicates0)
),
{ list__append(Predicates0, Predicates1, Predicates) },
% and generate the code for the rest of the predicates
generate_pred_list_code(ModuleInfo1, ModuleInfo, PredIds, Predicates1).
% Translate a HLDS predicate to LLDS.
:- pred generate_pred_code(module_info::in, module_info::out,
pred_id::in, pred_info::in, list(proc_id)::in, list(c_procedure)::out,
io__state::di, io__state::uo) is det.
generate_pred_code(ModuleInfo0, ModuleInfo, PredId, PredInfo, ProcIds, Code) -->
globals__io_lookup_bool_option(very_verbose, VeryVerbose),
( { VeryVerbose = yes } ->
io__write_string("% Generating code for "),
hlds_out__write_pred_id(ModuleInfo0, PredId),
io__write_string("\n"),
globals__io_lookup_bool_option(statistics, Statistics),
maybe_report_stats(Statistics)
;
[]
),
{ module_info_get_global_data(ModuleInfo0, GlobalData0) },
{ module_info_get_cell_count(ModuleInfo0, CellCount0) },
globals__io_get_globals(Globals),
{ generate_proc_list_code(ProcIds, PredId, PredInfo, ModuleInfo0,
Globals, GlobalData0, GlobalData, CellCount0, CellCount,
[], Code) },
{ module_info_set_cell_count(ModuleInfo0, CellCount, ModuleInfo1) },
{ module_info_set_global_data(ModuleInfo1, GlobalData,
ModuleInfo) }.
% Translate all the procedures of a HLDS predicate to LLDS.
:- pred generate_proc_list_code(list(proc_id)::in, pred_id::in, pred_info::in,
module_info::in, globals::in, global_data::in, global_data::out,
int::in, int::out, list(c_procedure)::in, list(c_procedure)::out)
is det.
generate_proc_list_code([], _PredId, _PredInfo, _ModuleInfo, _Globals,
GlobalData, GlobalData, CellCount, CellCount, Procs, Procs).
generate_proc_list_code([ProcId | ProcIds], PredId, PredInfo, ModuleInfo0,
Globals, GlobalData0, GlobalData, CellCount0, CellCount,
Procs0, Procs) :-
pred_info_procedures(PredInfo, ProcInfos),
map__lookup(ProcInfos, ProcId, ProcInfo),
generate_proc_code(PredInfo, ProcInfo, ProcId, PredId, ModuleInfo0,
Globals, GlobalData0, GlobalData1, CellCount0, CellCount1,
Proc),
generate_proc_list_code(ProcIds, PredId, PredInfo, ModuleInfo0,
Globals, GlobalData1, GlobalData, CellCount1, CellCount,
[Proc | Procs0], Procs).
%---------------------------------------------------------------------------%
% Values of this type hold information about stack frames that is
% generated when generating prologs and is used in generating epilogs
% and when massaging the code generated for the procedure.
:- type frame_info
---> frame(
int, % Number of slots in frame.
maybe(int), % Slot number of succip if succip is
% present in a general slot.
bool % Is this the frame of a model_non
% proc defined via pragma C code?
).
%---------------------------------------------------------------------------%
generate_proc_code(PredInfo, ProcInfo, ProcId, PredId, ModuleInfo, Globals,
GlobalData0, GlobalData, CellCount0, CellCount, Proc) :-
proc_info_interface_determinism(ProcInfo, Detism),
proc_info_interface_code_model(ProcInfo, CodeModel),
proc_info_goal(ProcInfo, Goal),
proc_info_varset(ProcInfo, VarSet),
proc_info_liveness_info(ProcInfo, Liveness),
proc_info_stack_slots(ProcInfo, StackSlots),
proc_info_get_initial_instmap(ProcInfo, ModuleInfo, InitialInst),
Goal = _ - GoalInfo,
goal_info_get_follow_vars(GoalInfo, MaybeFollowVars),
(
MaybeFollowVars = yes(FollowVars)
;
MaybeFollowVars = no,
map__init(FollowVars)
),
continuation_info__basic_stack_layout_for_proc(PredInfo, Globals,
BasicStackLayout, ForceProcId),
( BasicStackLayout = yes ->
SaveSuccip = yes
;
SaveSuccip = no
),
% Initialise the code_info structure. Generate_category_code
% below will use the returned OutsideResumePoint as the
% entry to the code that handles the failure of the procedure,
% if such code is needed. It is never needed for model_det
% procedures, always needed for model_semi procedures, and
% needed for model_non procedures only if we are doing
% execution tracing.
code_info__init(VarSet, Liveness, StackSlots, SaveSuccip, Globals,
PredId, ProcId, ProcInfo, InitialInst, FollowVars,
ModuleInfo, CellCount0, OutsideResumePoint, TraceSlotInfo,
CodeInfo0),
% Generate code for the procedure.
generate_category_code(CodeModel, Goal, OutsideResumePoint,
CodeTree, MaybeTraceCallLabel, FrameInfo, CodeInfo0, CodeInfo),
code_info__get_cell_count(CellCount, CodeInfo, _),
% Turn the code tree into a list.
tree__flatten(CodeTree, FragmentList),
% Now the code is a list of code fragments (== list(instr)),
% so we need to do a level of unwinding to get a flat list.
list__condense(FragmentList, Instructions0),
FrameInfo = frame(TotalSlots, MaybeSuccipSlot, _),
(
MaybeSuccipSlot = yes(SuccipSlot)
->
% The set of recorded live values at calls (for value
% numbering) and returns (for accurate gc and execution
% tracing) do not yet record the stack slot holding the
% succip, so add it to those sets.
code_gen__add_saved_succip(Instructions0,
SuccipSlot, Instructions)
;
Instructions = Instructions0
),
( BasicStackLayout = yes ->
% Create the procedure layout structure.
code_info__get_layout_info(InternalMap, CodeInfo, _),
code_util__make_local_entry_label(ModuleInfo, PredId, ProcId,
no, EntryLabel),
ProcLayout = proc_layout_info(EntryLabel, Detism, TotalSlots,
MaybeSuccipSlot, MaybeTraceCallLabel,
TraceSlotInfo, ForceProcId, InternalMap),
global_data_add_new_proc_layout(GlobalData0,
proc(PredId, ProcId), ProcLayout, GlobalData)
;
GlobalData = GlobalData0
),
predicate_name(ModuleInfo, PredId, Name),
predicate_arity(ModuleInfo, PredId, Arity),
% Construct a c_procedure structure with all the information.
Proc = c_procedure(Name, Arity, proc(PredId, ProcId), Instructions).
%---------------------------------------------------------------------------%
%---------------------------------------------------------------------------%
% Generate_category_code generates code for an entire procedure.
% Its algorithm has three or four main stages:
%
% - generate code for the body goal
% - generate code for the procedure entry
% - generate code for the procedure exit
% - generate code for the procedure fail (if needed)
%
% The first three tasks are forwarded to other procedures.
% The fourth task, if needed, is done by generate_category_code.
%
% The only caller of generate_category_code, generate_proc_code,
% has set up the code generator state to reflect what the machine
% state will be on entry to the procedure. Ensuring that the
% machine state at exit will conform to the expectation
% of the caller is the job of code_gen__generate_exit.
%
% The reason why we generate the entry code after the body is that
% information such as the total number of stack slots needed,
% which is needed in the procedure entry prologue, cannot be
% conveniently obtained before generating the body, since the
% code generator may allocate temporary variables to hold values
% such as saved heap and trail pointers.
%
% Code_gen__generate_entry cannot depend on the code generator
% state, since when it is invoked this state is not appropriate
% for the procedure entry. Nor can it change the code generator state,
% since that would confuse code_gen__generate_exit.
%
% Generating CALL trace events is done by generate_category_code,
% since only on entry to generate_category_code is the code generator
% state set up right. Generating EXIT trace events is done by
% code_gen__generate_exit. Generating FAIL trace events is done
% by generate_category_code, since this requires modifying how
% we generate code for the body of the procedure (failures must
% now branch to a different place). Since FAIL trace events are
% part of the failure continuation, generate_category_code takes
% care of the failure continuation as well. (Model_det procedures
% of course have no failure continuation. Model_non procedures have
% a failure continuation, but in the absence of tracing this
% continuation needs no code. Only model_semi procedures need code
% for the failure continuation at all times.)
:- pred generate_category_code(code_model::in, hlds_goal::in,
resume_point_info::in, code_tree::out, maybe(label)::out,
frame_info::out, code_info::in, code_info::out) is det.
generate_category_code(model_det, Goal, ResumePoint, Code,
MaybeTraceCallLabel, FrameInfo) -->
% generate the code for the body of the clause
(
code_info__get_globals(Globals),
{ globals__lookup_bool_option(Globals, middle_rec, yes) },
middle_rec__match_and_generate(Goal, MiddleRecCode)
->
{ Code = MiddleRecCode },
{ MaybeTraceCallLabel = no },
{ FrameInfo = frame(0, no, no) }
;
code_info__get_maybe_trace_info(MaybeTraceInfo),
( { MaybeTraceInfo = yes(TraceInfo) } ->
trace__generate_external_event_code(call, TraceInfo,
TraceCallLabel, _TypeInfos, TraceCallCode),
{ MaybeTraceCallLabel = yes(TraceCallLabel) }
;
{ TraceCallCode = empty },
{ MaybeTraceCallLabel = no }
),
code_gen__generate_goal(model_det, Goal, BodyCode),
code_gen__generate_entry(model_det, Goal, ResumePoint,
FrameInfo, EntryCode),
code_gen__generate_exit(model_det, FrameInfo, _, ExitCode),
{ Code =
tree(EntryCode,
tree(TraceCallCode,
tree(BodyCode,
ExitCode)))
}
).
generate_category_code(model_semi, Goal, ResumePoint, Code,
MaybeTraceCallLabel, FrameInfo) -->
{ set__singleton_set(FailureLiveRegs, reg(r, 1)) },
{ FailCode = node([
assign(reg(r, 1), const(false)) - "Fail",
livevals(FailureLiveRegs) - "",
goto(succip) - "Return from procedure call"
]) },
code_info__get_maybe_trace_info(MaybeTraceInfo),
( { MaybeTraceInfo = yes(TraceInfo) } ->
trace__generate_external_event_code(call, TraceInfo,
TraceCallLabel, _TypeInfos, TraceCallCode),
{ MaybeTraceCallLabel = yes(TraceCallLabel) },
code_gen__generate_goal(model_semi, Goal, BodyCode),
code_gen__generate_entry(model_semi, Goal, ResumePoint,
FrameInfo, EntryCode),
code_gen__generate_exit(model_semi, FrameInfo,
RestoreDeallocCode, ExitCode),
code_info__generate_resume_point(ResumePoint, ResumeCode),
{ code_info__resume_point_vars(ResumePoint, ResumeVarList) },
{ set__list_to_set(ResumeVarList, ResumeVars) },
code_info__set_forward_live_vars(ResumeVars),
trace__generate_external_event_code(fail, TraceInfo, _, _,
TraceFailCode),
{ Code =
tree(EntryCode,
tree(TraceCallCode,
tree(BodyCode,
tree(ExitCode,
tree(ResumeCode,
tree(TraceFailCode,
tree(RestoreDeallocCode,
FailCode)))))))
}
;
{ MaybeTraceCallLabel = no },
code_gen__generate_goal(model_semi, Goal, BodyCode),
code_gen__generate_entry(model_semi, Goal, ResumePoint,
FrameInfo, EntryCode),
code_gen__generate_exit(model_semi, FrameInfo,
RestoreDeallocCode, ExitCode),
code_info__generate_resume_point(ResumePoint, ResumeCode),
{ Code =
tree(EntryCode,
tree(BodyCode,
tree(ExitCode,
tree(ResumeCode,
tree(RestoreDeallocCode,
FailCode)))))
}
).
generate_category_code(model_non, Goal, ResumePoint, Code,
MaybeTraceCallLabel, FrameInfo) -->
code_info__get_maybe_trace_info(MaybeTraceInfo),
( { MaybeTraceInfo = yes(TraceInfo) } ->
trace__generate_external_event_code(call, TraceInfo,
TraceCallLabel, _TypeInfos, TraceCallCode),
{ MaybeTraceCallLabel = yes(TraceCallLabel) },
code_gen__generate_goal(model_non, Goal, BodyCode),
code_gen__generate_entry(model_non, Goal, ResumePoint,
FrameInfo, EntryCode),
code_gen__generate_exit(model_non, FrameInfo, _, ExitCode),
code_info__generate_resume_point(ResumePoint, ResumeCode),
{ code_info__resume_point_vars(ResumePoint, ResumeVarList) },
{ set__list_to_set(ResumeVarList, ResumeVars) },
code_info__set_forward_live_vars(ResumeVars),
trace__generate_external_event_code(fail, TraceInfo, _, _,
TraceFailCode),
{ FailCode = node([
goto(do_fail) - "fail after fail trace port"
]) },
{ Code =
tree(EntryCode,
tree(TraceCallCode,
tree(BodyCode,
tree(ExitCode,
tree(ResumeCode,
tree(TraceFailCode,
FailCode))))))
}
;
{ MaybeTraceCallLabel = no },
code_gen__generate_goal(model_non, Goal, BodyCode),
code_gen__generate_entry(model_non, Goal, ResumePoint,
FrameInfo, EntryCode),
code_gen__generate_exit(model_non, FrameInfo, _, ExitCode),
{ Code =
tree(EntryCode,
tree(BodyCode,
ExitCode))
}
).
%---------------------------------------------------------------------------%
% Generate the prologue for a procedure.
%
% The prologue will contain
%
% a comment to mark prologue start
% a comment explaining the stack layout
% the procedure entry label
% code to allocate a stack frame
% code to fill in some special slots in the stack frame
% a comment to mark prologue end
%
% At the moment the only special slots are the succip slot, and
% the slots holding the call number and call depth for tracing.
%
% Not all frames will have all these components. For example, the code
% to allocate a stack frame will be missing if the procedure doesn't
% need a stack frame, and if the procedure is nondet, then the code
% to fill in the succip slot is subsumed by the mkframe.
:- pred code_gen__generate_entry(code_model::in, hlds_goal::in,
resume_point_info::in, frame_info::out, code_tree::out,
code_info::in, code_info::out) is det.
code_gen__generate_entry(CodeModel, Goal, OutsideResumePoint,
FrameInfo, EntryCode) -->
code_info__get_stack_slots(StackSlots),
code_info__get_varset(VarSet),
{ code_aux__explain_stack_slots(StackSlots, VarSet, SlotsComment) },
{ StartComment = node([
comment("Start of procedure prologue") - "",
comment(SlotsComment) - ""
]) },
code_info__get_total_stackslot_count(MainSlots),
code_info__get_pred_id(PredId),
code_info__get_proc_id(ProcId),
code_info__get_module_info(ModuleInfo),
{ code_util__make_local_entry_label(ModuleInfo, PredId, ProcId, no,
Entry) },
{ LabelCode = node([
label(Entry) - "Procedure entry point"
]) },
code_info__get_succip_used(Used),
(
% Do we need to save the succip across calls?
{ Used = yes },
% Do we need to use a general slot for storing succip?
{ CodeModel \= model_non }
->
{ SuccipSlot is MainSlots + 1 },
{ SaveSuccipCode = node([
assign(stackvar(SuccipSlot), lval(succip)) -
"Save the success ip"
]) },
{ TotalSlots = SuccipSlot },
{ MaybeSuccipSlot = yes(SuccipSlot) }
;
{ SaveSuccipCode = empty },
{ TotalSlots = MainSlots },
{ MaybeSuccipSlot = no }
),
code_info__get_maybe_trace_info(MaybeTraceInfo),
( { MaybeTraceInfo = yes(TraceInfo) } ->
trace__generate_slot_fill_code(TraceInfo, TraceFillCode)
;
{ TraceFillCode = empty }
),
{ predicate_module(ModuleInfo, PredId, ModuleName) },
{ predicate_name(ModuleInfo, PredId, PredName) },
{ predicate_arity(ModuleInfo, PredId, Arity) },
{ prog_out__sym_name_to_string(ModuleName, ModuleNameString) },
{ string__int_to_string(Arity, ArityStr) },
{ string__append_list([ModuleNameString, ":", PredName, "/", ArityStr],
PushMsg) },
(
{ CodeModel = model_non }
->
{ code_info__resume_point_stack_addr(OutsideResumePoint,
OutsideResumeAddress) },
(
{ Goal = pragma_c_code(_,_,_,_,_,_, PragmaCode) - _},
{ PragmaCode = nondet(Fields, FieldsContext,
_,_,_,_,_,_,_) }
->
{ pragma_c_gen__struct_name(ModuleName, PredName,
Arity, ProcId, StructName) },
{ Struct = pragma_c_struct(StructName,
Fields, FieldsContext) },
{ string__format("#define\tMR_ORDINARY_SLOTS\t%d\n",
[i(TotalSlots)], DefineStr) },
{ DefineComponents = [pragma_c_raw_code(DefineStr)] },
{ NondetFrameInfo = ordinary_frame(PushMsg, TotalSlots,
yes(Struct)) },
{ AllocCode = node([
mkframe(NondetFrameInfo, OutsideResumeAddress)
- "Allocate stack frame",
pragma_c([], DefineComponents,
will_not_call_mercury, no, no)
- ""
]) },
{ NondetPragma = yes }
;
{ NondetFrameInfo = ordinary_frame(PushMsg, TotalSlots,
no) },
{ AllocCode = node([
mkframe(NondetFrameInfo, OutsideResumeAddress)
- "Allocate stack frame"
]) },
{ NondetPragma = no }
)
;
{ TotalSlots > 0 }
->
{ AllocCode = node([
incr_sp(TotalSlots, PushMsg) -
"Allocate stack frame"
]) },
{ NondetPragma = no }
;
{ AllocCode = empty },
{ NondetPragma = no }
),
{ FrameInfo = frame(TotalSlots, MaybeSuccipSlot, NondetPragma) },
{ EndComment = node([
comment("End of procedure prologue") - ""
]) },
{ EntryCode =
tree(StartComment,
tree(LabelCode,
tree(AllocCode,
tree(SaveSuccipCode,
tree(TraceFillCode,
EndComment)))))
}.
%---------------------------------------------------------------------------%
% Generate the success epilogue for a procedure.
%
% The success epilogue will contain
%
% a comment to mark epilogue start
% code to place the output arguments where their caller expects
% code to restore registers from some special slots
% code to deallocate the stack frame
% code to set r1 to TRUE (for semidet procedures only)
% a jump back to the caller, including livevals information
% a comment to mark epilogue end
%
% The parts of this that restore registers and deallocate the stack
% frame are also part of the failure epilog, which is handled by
% our caller; this is why we return RestoreDeallocCode.
%
% At the moment the only special slots are the succip slot, and
% the slots holding the call number and call depth for tracing.
%
% Not all frames will have all these components. For example, for
% nondet procedures we don't deallocate the stack frame before
% success.
%
% Epilogues for procedures defined by nondet pragma C codes do not
% follow the rules above. For such procedures, the normal functions
% of the epilogue are handled when traversing the pragma C code goal;
% we need only #undef a macro defined by the procedure prologue.
:- pred code_gen__generate_exit(code_model::in, frame_info::in,
code_tree::out, code_tree::out, code_info::in, code_info::out) is det.
code_gen__generate_exit(CodeModel, FrameInfo, RestoreDeallocCode, ExitCode) -->
{ StartComment = node([
comment("Start of procedure epilogue") - ""
]) },
{ EndComment = node([
comment("End of procedure epilogue") - ""
]) },
{ FrameInfo = frame(TotalSlots, MaybeSuccipSlot, NondetPragma) },
( { NondetPragma = yes } ->
{ UndefStr = "#undef\tMR_ORDINARY_SLOTS\n" },
{ UndefComponents = [pragma_c_raw_code(UndefStr)] },
{ UndefCode = node([
pragma_c([], UndefComponents,
will_not_call_mercury, no, no)
- ""
]) },
{ RestoreDeallocCode = empty }, % always empty for nondet code
{ ExitCode =
tree(StartComment,
tree(UndefCode,
EndComment))
}
;
code_info__get_instmap(Instmap),
code_info__get_arginfo(ArgModes),
code_info__get_headvars(HeadVars),
{ assoc_list__from_corresponding_lists(HeadVars, ArgModes,
Args)},
(
{ instmap__is_unreachable(Instmap) }
->
{ FlushCode = empty }
;
code_info__setup_call(Args, callee, FlushCode)
),
(
{ MaybeSuccipSlot = yes(SuccipSlot) }
->
{ RestoreSuccipCode = node([
assign(succip, lval(stackvar(SuccipSlot))) -
"restore the success ip"
]) }
;
{ RestoreSuccipCode = empty }
),
(
{ TotalSlots = 0 ; CodeModel = model_non }
->
{ DeallocCode = empty }
;
{ DeallocCode = node([
decr_sp(TotalSlots) - "Deallocate stack frame"
]) }
),
{ RestoreDeallocCode = tree(RestoreSuccipCode, DeallocCode ) },
code_info__get_maybe_trace_info(MaybeTraceInfo),
( { MaybeTraceInfo = yes(TraceInfo) } ->
trace__generate_external_event_code(exit, TraceInfo,
_, TypeInfoDatas, TraceExitCode),
{ map__values(TypeInfoDatas, TypeInfoLocnSets) },
{ FindBaseLvals = lambda([Lval::out] is nondet, (
list__member(LocnSet, TypeInfoLocnSets),
set__member(Locn, LocnSet),
(
Locn = direct(Lval)
;
Locn = indirect(Lval, _)
)
)) },
{ solutions(FindBaseLvals, TypeInfoLvals) }
;
{ TraceExitCode = empty },
{ TypeInfoLvals = [] }
),
% Find out which locations should be mentioned
% in the success path livevals(...) annotation,
% so that value numbering doesn't optimize them away.
{ code_gen__select_args_with_mode(Args, top_out, _OutVars,
OutLvals) },
{ list__append(TypeInfoLvals, OutLvals, LiveArgLvals) },
{ set__list_to_set(LiveArgLvals, LiveArgs) },
(
{ CodeModel = model_det },
{ SuccessCode = node([
livevals(LiveArgs) - "",
goto(succip) - "Return from procedure call"
]) },
{ AllSuccessCode =
tree(TraceExitCode,
tree(RestoreDeallocCode,
SuccessCode))
}
;
{ CodeModel = model_semi },
{ set__insert(LiveArgs, reg(r, 1), SuccessLiveRegs) },
{ SuccessCode = node([
assign(reg(r, 1), const(true)) - "Succeed",
livevals(SuccessLiveRegs) - "",
goto(succip) - "Return from procedure call"
]) },
{ AllSuccessCode =
tree(TraceExitCode,
tree(RestoreDeallocCode,
SuccessCode))
}
;
{ CodeModel = model_non },
{ MaybeTraceInfo = yes(TraceInfo2) ->
trace__maybe_setup_redo_event(TraceInfo2,
SetupRedoCode)
;
SetupRedoCode = empty
},
{ SuccessCode = node([
livevals(LiveArgs) - "",
goto(do_succeed(no))
- "Return from procedure call"
]) },
{ AllSuccessCode =
tree(SetupRedoCode,
tree(TraceExitCode,
SuccessCode))
}
),
{ ExitCode =
tree(StartComment,
tree(FlushCode,
tree(AllSuccessCode,
EndComment)))
}
).
%---------------------------------------------------------------------------%
% Generate a goal. This predicate arranges for the necessary updates of
% the generic data structures before and after the actual code generation,
% which is delegated to goal-specific predicates.
code_gen__generate_goal(ContextModel, Goal - GoalInfo, Code) -->
% Make any changes to liveness before Goal
{ goal_is_atomic(Goal) ->
IsAtomic = yes
;
IsAtomic = no
},
code_info__pre_goal_update(GoalInfo, IsAtomic),
code_info__get_instmap(Instmap),
(
{ instmap__is_reachable(Instmap) }
->
{ goal_info_get_code_model(GoalInfo, CodeModel) },
% sanity check: code of some code models
% should occur only in limited contexts
{
CodeModel = model_det
;
CodeModel = model_semi,
( ContextModel \= model_det ->
true
;
error("semidet model in det context")
)
;
CodeModel = model_non,
( ContextModel = model_non ->
true
;
error("nondet model in det/semidet context")
)
},
code_gen__generate_goal_2(Goal, GoalInfo, CodeModel, Code),
% Make live any variables which subsequent goals
% will expect to be live, but were not generated
code_info__set_instmap(Instmap),
code_info__post_goal_update(GoalInfo)
;
{ Code = empty }
),
!.
%---------------------------------------------------------------------------%
:- pred code_gen__generate_goal_2(hlds_goal_expr::in, hlds_goal_info::in,
code_model::in, code_tree::out, code_info::in, code_info::out) is det.
code_gen__generate_goal_2(unify(_, _, _, Uni, _), _, CodeModel, Code) -->
unify_gen__generate_unification(CodeModel, Uni, Code).
code_gen__generate_goal_2(conj(Goals), _GoalInfo, CodeModel, Code) -->
code_gen__generate_goals(Goals, CodeModel, Code).
code_gen__generate_goal_2(par_conj(Goals, _SM), GoalInfo, CodeModel, Code) -->
par_conj_gen__generate_par_conj(Goals, GoalInfo, CodeModel, Code).
code_gen__generate_goal_2(disj(Goals, StoreMap), _, CodeModel, Code) -->
disj_gen__generate_disj(CodeModel, Goals, StoreMap, Code).
code_gen__generate_goal_2(not(Goal), _GoalInfo, CodeModel, Code) -->
ite_gen__generate_negation(CodeModel, Goal, Code).
code_gen__generate_goal_2(if_then_else(_Vars, Cond, Then, Else, StoreMap),
_GoalInfo, CodeModel, Code) -->
ite_gen__generate_ite(CodeModel, Cond, Then, Else, StoreMap, Code).
code_gen__generate_goal_2(switch(Var, CanFail, CaseList, StoreMap),
GoalInfo, CodeModel, Code) -->
switch_gen__generate_switch(CodeModel, Var, CanFail, CaseList,
StoreMap, GoalInfo, Code).
code_gen__generate_goal_2(some(_Vars, Goal), _GoalInfo, CodeModel, Code) -->
commit_gen__generate_commit(CodeModel, Goal, Code).
code_gen__generate_goal_2(higher_order_call(PredVar, Args, Types,
Modes, Det, _PredOrFunc), GoalInfo, CodeModel, Code) -->
call_gen__generate_higher_order_call(CodeModel, PredVar, Args,
Types, Modes, Det, GoalInfo, Code).
code_gen__generate_goal_2(class_method_call(TCVar, Num, Args, Types,
Modes, Det), GoalInfo, CodeModel, Code) -->
call_gen__generate_class_method_call(CodeModel, TCVar, Num, Args,
Types, Modes, Det, GoalInfo, Code).
code_gen__generate_goal_2(call(PredId, ProcId, Args, BuiltinState, _, _),
GoalInfo, CodeModel, Code) -->
(
{ BuiltinState = not_builtin }
->
call_gen__generate_call(CodeModel, PredId, ProcId, Args,
GoalInfo, Code)
;
call_gen__generate_builtin(CodeModel, PredId, ProcId, Args,
Code)
).
code_gen__generate_goal_2(pragma_c_code(Attributes,
PredId, ModeId, Args, ArgNames, OrigArgTypes, PragmaCode),
GoalInfo, CodeModel, Instr) -->
pragma_c_gen__generate_pragma_c_code(CodeModel, Attributes,
PredId, ModeId, Args, ArgNames, OrigArgTypes, GoalInfo,
PragmaCode, Instr).
%---------------------------------------------------------------------------%
% Generate a conjoined series of goals.
% Note of course, that with a conjunction, state information
% flows directly from one conjunct to the next.
:- pred code_gen__generate_goals(hlds_goals::in, code_model::in,
code_tree::out, code_info::in, code_info::out) is det.
code_gen__generate_goals([], _, empty) --> [].
code_gen__generate_goals([Goal | Goals], CodeModel, Instr) -->
code_gen__generate_goal(CodeModel, Goal, Instr1),
code_info__get_instmap(Instmap),
(
{ instmap__is_unreachable(Instmap) }
->
{ Instr = Instr1 }
;
code_gen__generate_goals(Goals, CodeModel, Instr2),
{ Instr = tree(Instr1, Instr2) }
).
%---------------------------------------------------------------------------%
:- pred code_gen__select_args_with_mode(assoc_list(prog_var, arg_info)::in,
arg_mode::in, list(prog_var)::out, list(lval)::out) is det.
code_gen__select_args_with_mode([], _, [], []).
code_gen__select_args_with_mode([Var - ArgInfo | Args], DesiredMode, Vs, Ls) :-
code_gen__select_args_with_mode(Args, DesiredMode, Vs0, Ls0),
ArgInfo = arg_info(Loc, Mode),
(
Mode = DesiredMode
->
code_util__arg_loc_to_register(Loc, Reg),
Vs = [Var | Vs0],
Ls = [Reg | Ls0]
;
Vs = Vs0,
Ls = Ls0
).
%---------------------------------------------------------------------------%
% Add the succip to the livevals before and after calls.
% Traverses the list of instructions looking for livevals and calls,
% adding succip in the stackvar number given as an argument.
:- pred code_gen__add_saved_succip(list(instruction)::in, int::in,
list(instruction)::out) is det.
code_gen__add_saved_succip([], _StackLoc, []).
code_gen__add_saved_succip([Instrn0 - Comment | Instrns0 ], StackLoc,
[Instrn - Comment | Instrns]) :-
(
Instrn0 = livevals(LiveVals0),
Instrns0 \= [goto(succip) - _ | _]
% XXX We should also test for tailcalls
% once we start generating them directly.
->
set__insert(LiveVals0, stackvar(StackLoc), LiveVals1),
Instrn = livevals(LiveVals1)
;
Instrn0 = call(Target, ReturnLabel, LiveVals0, CM)
->
map__init(Empty),
Instrn = call(Target, ReturnLabel,
[live_lvalue(direct(stackvar(StackLoc)),
succip, Empty) |
LiveVals0], CM)
;
Instrn = Instrn0
),
code_gen__add_saved_succip(Instrns0, StackLoc, Instrns).
%---------------------------------------------------------------------------%
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