Commit Graph

4 Commits

Author SHA1 Message Date
Zoltan Somogyi
d10af74168 This change introduces interface tracing, and makes it possible to successfully
Estimated hours taken: 50

This change introduces interface tracing, and makes it possible to successfully
bootstrap the compiler with tracing (either interface or full).

compiler/options.m:
	Change the bool options --generate-trace into a string option --trace
	with three valid values: minimal, interface and full. The last two mean
	what they say; the intention is that eventually minimal will mean
	no tracing in non-tracing grades and interface tracing in tracing
	grades.

compiler/globals.m:
	Add a new global for the trace level.

compiler/handle_options.m:
	Convert the argument of --trace to a trace level.

	Use only consistent 4-space indentation in the deeply nested
	if-then-else.

compiler/trace.m:
	Implement interface tracing.

	Rename trace__generate_depth_reset_code as trace__prepare_for_call,
	since it does more than reset the depth if this module is compiled
	with interface tracing.

	Do not check whether tracing is enabled before calling MR_trace;
	let MR_trace make the check. This trades increased non-tracing
	execution time for a substantial code size reduction (which may
	in turn benefit execution time).

compiler/call_gen.m:
	Call trace__generate_depth_reset_code by its new name.

compiler/code_info.m:
	Fix a bug in the handling of non/semi commits. When entering a commit,
	we used to push a clone of whatever the top failure continuation was.
	However, the resume setup for this continuation could have started
	with a label that assumed that the resume vars were in their original
	locations (which are often registers), whereas the method of
	backtracking to that point only guarantees the survival of stack slots,
	not registers.

	(This bug caused two lines of incorrect code to be generated among
	the approx 30 million lines of code in the stage 2 compiler when
	compiled with tracing.)

	Fix another bug (previously untriggered as far as I know) in the
	handling of multi/det commits. This one was breaking the invariant
	that the resume vars set of each entry on the failure continuation
	stack included the resume vars set of every other entry below it,
	which meant that the values of these resume vars were not guaranteed
	to be preserved.

compiler/stack_layout.m:
	Make layout structures local to their module. They are not (yet)
	referred to by name from other modules, and by declaring them
	to be global we caused their names to be included even in stripped
	executables, adding several megabytes to the size of the binary.
	(The names are not stripped because a dynamically linked library
	may want to refer to them.)

	Change the mercury_data__stack_layout__ prefix on the names of
	generated globals vars to just mercury_data__layout__. It is now
	merely too long instead of far too long.

	Include the label number in the label layout structure and the number
	of typeinfo variables in a var_info structure only with native gc.
	Their only use is in debugging native gc.

	Fix some documentation rot.

compiler/llds.m:
	Add a new field to the pragma_c instruction that says whether the
	compiler-generated C code fragments access any stack variables.

compiler/frameopt.m:
	Use the new field in pragma_c's to avoid a bug. Because frameopt was
	assuming that the pragma_c instruction that filled in the stack slots
	containing the call sequence number and depth did not access the stack,
	it moved the pragma_c before the incr_sp that allocates the frame
	(it was trying to get it out of the loop).

compiler/*.m:
	Minor changes to set or ignore the extra field in pragma_c, to refer
	to layout structures via the new prefix, or to handle the --trace
	option.

doc/user_guide.texi:
	Update the documentation for --trace.

runtime/mercury_types.h:
	Add the type Unsigned.

runtime/mercury_goto.h:
	Use the shorter layout prefix.

runtime/mercury_stack_layout.h:
	Use the shorter layout prefix, and include the label number only with
	native gc.

runtime/mercury_trace.[ch]:
runtime/mercury_trace_internal.[ch]:
runtime/mercury_trace_external.[ch]:
runtime/mercury_trace_util.[ch]:
	Divide the old mercury_trace.[ch] into several components, with one
	module for the internal debugger, one for the interface to the
	external debugger, one for utilities needed by both. Mercury_trace.c
	now has only the top-level stuff that steers between the two
	debuggers.

runtime/mercury_trace.[ch]:
	Add the new global variable MR_trace_from_full. Before each call,
	the calling procedure assigns TRUE to this variable if the caller
	is fully traced, and FALSE otherwise. Interface traced procedures
	generate trace events only if this variable is TRUE when they are
	called (fully traced callee procedures ignore the initial value of
	the variable).

	Make MR_trace return immediately without doing anything unless
	tracing is enabled and a new extra argument to MR_trace is TRUE.
	This extra argument is always TRUE for trace events in fully traced
	procedures, while for trace events from interface traced procedures,
	its value is set from the value of MR_trace_from_full at the time
	that the procedure was called (i.e. the event is ignored unless the
	interface traced procedure was called from a fully traced procedure).

runtime/mercury_trace.[ch]:
runtime/mercury_trace_internal.[ch]:
	For global variables that are stored in stack slots, make their type
	Word rather than int.

	Use a new function MR_trace_event_report instead of calling
	MR_trace_event with a NULL command structure pointer to indicate
	that the event is to be reported but there is to be no user
	interaction.

	Use %ld formats in printfs and casts to long for better portability.

runtime/mercury_trace_internal.c:
	Save trace-related globals across calls to Mercury library code
	in the debugger, since otherwise any trace events in this code
	could screw up e.g. the event number or the call number sequence.

	Create separate functions for printing port names and determinisms.

runtime/mercury_wrapper.h:
	Disable the tracing of the initialization and finalization code
	written in Mercury.

runtime/Mmakefile:
	Update for the new source and header files.

tests/debugger/{debugger_regs,interpreter,queens}_lib.{m,inp,exp}:
	One new copy of each existing test case. These ones are intended
	to be used when the stage 2 library is compiled with tracing, which
	affects the tests by adding events for the library procedures called
	from the test programs.

	The .m files are the same as before; one of the .inp files is a bit
	different; the .exp files reflect the correct output when the library
	is compiled with full tracing.

tests/debugger/Mmakefile:
	Provide separate targets for the new set of test cases.

	Use --trace full instead of --generate-trace.

tests/debugger/runtests:
	Try both the new set of test cases if the old set fails, and report
	failure only if both sets fail. This is simpler than trying to figure
	out which set should be really tested, and the probability of a false
	positive is negligible.
1998-05-16 07:31:33 +00:00
Zoltan Somogyi
5013dd9c76 Implement nondet pragma C codes.
Estimated hours taken: 40

Implement nondet pragma C codes.

runtime/mercury_stacks.h:
	Define a new macro, mkpragmaframe, for use in the implementation
	of nondet pragma C codes. This new macro includes space for a
	struct with a given sruct tag in the nondet stack frame being created.

compiler/{prog_data.m,hlds_goal.m}:
	Revise the representation of pragma C codes, both as the item and
	in the HLDS.

compiler/prog_io_pragma.m:
	Parse nondet pragma C declarations.

	Fix the indentation in some places.

compiler/llds.m:
	Include an extra argument in mkframe instructions. This extra argument
	gives the details of the C structure (if any) to be included in the
	nondet stack frame to be created.

	Generalize the LLDS representation of pragma C codes. Instead of a
	fixed sequence of <assign from inputs, user c code, assign to outputs>,
	let the sequence contain these elements, as well as arbitrary
	compiler-generated C code, in any order and possibly with repetitions.
	This flexibility is needed for nondet pragma C codes.

	Add a field to pragma C codes to say whether they can call Mercury.
	Some optimizations can do a better job if they know that a pragma C
	code cannot call Mercury.

	Add another field to pragma C codes to give the name of the label
	they refer to (if any). This is needed to prevent labelopt from
	incorrectly optimizing away the label definition.

	Add a new alternative to the type pragma_c_decl, to describe the
	declaration of the local variable that points to the save struct.

compiler/llds_out.m:
	Output mkframe instructions that specify a struct as invoking the new
	mkpragmaframe macro, and make sure that the struct is declared just
	before the procedure that uses it.

	Other minor changes to keep up with the changes to the representation
	of pragma C code in the LLDS, and to make the output look a bit nicer.

compiler/pragma_c_gen.m:
	Add code to generate code for nondet pragma C codes. Revise the utility
	predicates and their data structures a bit to make this possible.

compiler/code_gen.m:
	Add code for the necessary special handling of prologs and epilogs
	of procedures defined by nondet pragma C codes. The prologs need
	to be modified to include a programmer-defined C structure in the
	nondet stack frame and to communicate the location of this structure
	to the pragma C code, whereas the functionality of the epilog is
	taken care of by the pragma C code itself.

compiler/make_hlds.m:
	When creating a proc_info for a procedure defined by a pragma C code,
	we used to insert unifications between the headvars and the vars of
	the pragma C code into the body goal. We now perform substitutions
	instead. This removes a factor that would complicate the generation
	of code for nondet pragma C codes.

	Pass a moduleinfo down the procedures that warn about singletons
	(and other basic scope errors). When checking whether to warn about
	an argument of a pragma C code not being mentioned in the C code
	fragment, we need to know whether the argument is input or output,
	since input variables should appear in some code fragments in a
	nondet pragma C code and must not appear in others. The
	mode_is_{in,out}put checks need the moduleinfo.

	(We do not need to check for any variables being mentioned where
	they shouldn't be. The C compiler will fail in the presence of any
	errors of that type, and since those variables could be referred
	to via macros whose definitions we do not see, we couldn't implement
	a reliable test anyway.)

compiler/opt_util.m:
	Recognize that some sorts of pragma_c codes cannot affect the data
	structures that control backtracking. This allows peepholing to
	do a better job on code sequences produced for nondet pragma C codes.

	Recognize that the C code strings inside some pragma_c codes refer to
	other labels in the procedure. This prevents labelopt from incorrectly
	optimizing away these labels.

compiler/dupelim.m:
	If a label is referred to from within a C code string, then do not
	attempt to optimize it away.

compiler/det_analysis.m:
	Remove a now incorrect part of an error message.

compiler/*.m:
	Minor changes to conform to changes to the HLDS and LLDS data
	structures.
1998-01-13 10:14:23 +00:00
Zoltan Somogyi
bb4442ddc1 Update copyright dates for 1998.
Estimated hours taken: 0.5

compiler/*.m:
	Update copyright dates for 1998.
1998-01-13 10:06:08 +00:00
Zoltan Somogyi
42c540ad67 Give duplicate code elimination more teeth in dealing with similar arguments
Estimated hours taken: 20

Give duplicate code elimination more teeth in dealing with similar arguments
of different function symbols. For the source code

	:- type t1	--->	f(int)
			;	g(int, int).

	:- pred p1(t1::in, int::out) is det.

	p1(f(Y), Y).
	p1(g(Y, _), Y).

we now generate the C code

	Define_entry(mercury__xdup__p1_2_0);
		r1 = const_mask_field(r1, (Integer) 0);
		proceed();

thus avoiding the cost of testing the function symbol.

runtime/mercury_tags.h:
	Add two new macros, mask_field and const_mask_field, that behave
	just like field and const_field except that instead of stripping
	off a known tag from the pointer, they strip (mask) off an unknown
	tag.

compiler/llds.m:
	Change the first argument of the lval field/3 from tag to maybe(tag).

	Make the comments on some types more readable.

compiler/llds_out.m:
	If the first arg of the lval field/3 is no, emit a (const_)mask_field
	macro; otherwise, emit a (const_)field macro.

compiler/basic_block.m:
	New module to convert sequences of instructions to sequences of
	basic blocks and vice versa. Used in the new dupelim.m.

compiler/dupelim.m:
	Complete rewrite to give duplicate code elimination more teeth.
	Whereas previously we eliminated blocks of code only if they exactly
	duplicated other blocks of code, we now look for blocks that can be
	"anti-unified". For example, the blocks

	r1 = field(mktag(0), r2, 0)
	goto L1

	and

	r1 = field(mktag(1), r2, 0)
	<fall through to L1>

	anti-unify, with the most specific common generalization being

	r1 = mask_field(r2, 0)
	goto L1

	If several basic blocks antiunify, we replace one copy with the
	antiunified block and try to eliminate the others. We do not
	eliminate blocks that can be fallen into, since eliminating them
	would require introducing a goto, which would slow the code down.

compiler/peephole,m:
	If a conditional branch to a label is followed by that label or
	by an unconditional branch to that label, eliminate the branch.
	Dupelim produces this kind of code.

compiler/{code_exprn,exprn_aux,lookup_switch,opt_debug,unify_gen}.m:
	Minor changes required by the change to field/3.

compiler/{frameopt,jumpopt,labelopt,mercury_compile,optimize,value_number}.m:
	s/__main/_main/ in predicate names.

compiler/jumpopt.m:
	Add some documentation.

compiler/unify_gen.m:
	Fix a module qualified predicate name reference that would not
	work in Prolog.

compiler/notes/compiler_design.html:
	Document the new file basic_block.m.
1997-12-22 06:59:25 +00:00