2 Commits

Author SHA1 Message Date
Zoltan Somogyi
13f0e7610a A large step towards declarative debugging of goals that do I/O.
Estimated hours taken: 40
Branches: main

A large step towards declarative debugging of goals that do I/O. This step
does everything needed for that except modify the declarative debugger itself;
that is for Mark to do.

If you give the new option --trace-table-io-decl, the transformation performed
by the compiler on I/O primitives will preserve not just the output arguments
of the primitive, so that the primitive can be "reexecuted" without performing
any side-effects, but also the input arguments and the identity of the I/O
primitive itself. The I/O table therefore will contain a list of the I/O
primitives executed by the program after I/O tabling is started.

You can test this via the new debugger commands "print action <action-number>"
and "browse action <action-number>".

The new option is currently not documented, because the declarative debugger
does not yet use the information it provides. The new debugger commands are
not documented because they are meant only for implementors, at least for
now.

Since this change adds a field to proc_layout structures, any workspaces
compiled with debugging enabled will need to do a cvs update when this change
is installed.

compiler/options.m:
	Add the option --trace-table-io-decl. When set, this causes the
	compiler to transform I/O action primitives to allow declarative
	debugging of I/O actions.

compiler/handle_options.m:
	Make --trace-table-io-decl imply --trace-table-io.

compiler/table_gen.m:
	Perform the transformation, which is similar to the existing
	--trace-table-io transformation, but preserves the identity of all
	non-io-state arguments (not just the outputs) and the identity
	of the I/O primitive itself.

	Provide better names for variables generated by tabling
	transformations.

compiler/hlds_goal.m:
	Add extra parameters to procedures whose job it is to create new
	goals to name the variables in those goals.

compiler/layout.m:
	Add a new layout structure to contain the information the runtime
	system needs to interpret the information saved by the new
	transformation.

compiler/layout_out.m:
	Output the new layout structure.

compiler/continuation_info.m:
	Add a field to proc_layouts to point to the declarative I/O tabling
	structure, and another to identify the proc_layout without using LLDS
	types.

compiler/code_gen.m:
	Provide the definition of this field when appropriate.

compiler/hlds_pred.m:
	Add a field to proc_infos to store the information from the tabling
	transformation until code generation.

compiler/stack_layout.m:
	Add a mechanism for transforming the high level description of I/O
	action tabling data in proc_infos to the low level description we need
	to generate C data structures.

compiler/hlds_data.m:
	Add a new cons_id and a new cons_tag; they are used to refer to I/O
	tabling structures in code generated by the new transformation.

compiler/*.m:
	Handle the updates to global data types above.

library/table_builtin.m:
	Modernize some old code.

	Fix an old off-by-one error: make I/O tabling use the first slot
	in the I/O action table.

library/varset.m:
	Add a mechanism for creating a variable that is named iff the caller
	has a name for it.

runtime/mercury_layout_util.[ch]:
	Add a function for materializing type parameters from an answer block,
	not from registers or a closure.

runtime/mercury_stack_layout.h:
	Declare a C type for the data structure holding information about
	I/O primitives transformed by --trace-table-io-decl, and add a field
	to proc_layout structures to point to these new structures.

	Add a new evaluation method for --trace-table-io-decl.

runtime/mercury_tabling_macros.h:
	Add some conditionally-compiled debugging code to the primitive for
	saving answers.

trace/mercury_trace_vars.[ch]:
	Add functions for printing I/O action goals.

trace/mercury_trace_internal.c:
	Add code for recognizing and implementing commands to print I/O
	action goals.

trace/mercury_trace.c:
	Add code for handling the new eval method.

tests/debugger/tabled_read.{m,inp,exp*}:
	Add a polymorphic I/O action primitive, add calls to it, and test
	the printing of both monomorphic and polymorphic action goals.

tests/debugger/tabled_read_decl.{m,inp,exp*,data}:
	A new test case. It does the same things as the new version of
	tabled_read, but it is compiled with --trace-table-io-decl, not
	just --trace-table-io. It therefore can (and does) test the printing
	of tabled I/O actions.

tests/debugger/Mmakefile:
	Add the new test case.
2002-02-20 03:14:51 +00:00
Zoltan Somogyi
ebe9f9a3ec Add tabling of I/O actions for the debugger.
Estimated hours taken: 80

Add tabling of I/O actions for the debugger.

compiler/options.m:
	Add a new option, --trace-table-io, that enables the tabling of I/O
	actions, and another, --trace-table-io-states, that governs whether the
	tabling includes the I/O state variables themselves. (You want to table
	these variables iff they contain meaningful information that is not
	stored in global variables.) These options are for developers only
	for now.

compiler/modules.m:
	Implicitly import table_builtin if --trace-table-io is specified.

compiler/prog_data.m:
	Add eval_table_io as a new eval method.

compiler/hlds_pred.m:
	Add a mechanism for checking whether a predicate has an input/output
	pair of io__state args.

	Extend the tables indexed by eval_method to handle eval_table_io.

compiler/hlds_out.m:
	Print the eval method in HLDS dumps.

compiler/table_gen.m:
	If a procedure has a pair of I/O state args and is defined using pragma
	C code that has the tabled_for_io marker, and --trace-table-io is
	specified, then perform I/O tabling on it and mark it as tabled.

compiler/notes/compiler_design.m:
	Document that table_gen.m can now change the evaluation methods of
	procedures (to eval_table_io).

compiler/stack_layout.m:
runtime/mercury_stack_layout.h:
	Add an extra field to proc layouts. If debugging is enabled and a
	procedure has I/O state arguments, this field gives the number of the
	stack slot which will be filled with the I/O action counter at the
	time of the call, so that on retry the debugger can reset the I/O
	action counter to this value.

compiler/trace.m:
	Add code to reserve and fill this stack slot.

	Make the order of fields in the trace_slots structure match the order
	in proc layouts.

compiler/code_info.m:
compiler/live_vars.m:
	Pass a module_info to trace__setup and trace__reserved_slots.

library/io.m:
	Mark the I/O primitives (i.e. procedures that are defined by pragma C
	code and do I/O) with the tabled_for_io feature. (See the discussion
	of I/O primitives in compiler/table_gen.m.)

	Standardize the formatting of predicates defined by pragma C codes.

library/table_builtin.m:
	Define the predicates that perform I/O tabling, to which calls are
	inserted in I/O tabled predicates. These depend on knowing what the
	maximum MR_Unsigned value is.

library/table_builtin.m:
runtime/mercury_tabling_macros.h:
	Table nodes implementing a simple kind of trie, which can also be
	viewed as a hash table with the hash function hash(n) = hash - start
	were already supported by mercury_tabling.c. They are used to
	implement I/O tabling, since I/O the tabled action numbers form a
	contiguous sequence. Now allow that functionality to be accessed
	from the library through macros.

runtime/mercury_trace_base.[ch]:
	Add the global variables required by I/O tabling.

trace/mercury_trace.c:
	Implement retry across I/O by resetting the I/O counter to the value
	it had on entry to the retried call. However, since this is not safe
	in general, ask the user for permission first.

trace/mercury_trace.h:
	Add two extra arguments to MR_trace_retry to specify the input and
	output streams on which to ask permission.

trace/mercury_trace_internal.c:
	Add commands to start and stop I/O tabling. For now, they are for use
	by developers only and are undocumented; I expect they will change
	significantly before being let loose on users.

trace/mercury_trace_external.c:
trace/mercury_trace_declarative.c:
	Pass extra arguments to MR_trace_retry to indicate that these modules
	are not interested (at least for now) in retry across I/O, since they
	do not (yet) have mechanisms for asking the user for permission.

tests/debugger/tabled_read.{m,inp,exp,data}:
	A new test case to check retry across tabled and non-tabled I/O.

tests/debugger/Mmakefile:
	Enable the new test case.
2000-12-06 06:06:06 +00:00