Re: [PATCH 5/9] Introduce class function_reader

[David Malcolm <dmalcolm@redhat.com>]

On Fri, 2016-09-16 at 15:28 -0600, Jeff Law wrote:
> On 09/08/2016 06:30 PM, David Malcolm wrote:
> > This patch generalizes the RTL-reading capabilities so that they
> > can be run on the host as well as the build machine.
> > The available rtx in rtl.def changes dramatically between these
> > two configurations, so a fair amount of #ifdef GENERATOR_FILE is
> > required to express this.
> > 
> > This patch introduces a function_reader subclass of rtx_reader,
> > capable of reading an RTL function dump (or part of one),
> > reconstructing a cfun with a CFG and basic blocks containing insns.
> > 
> > gcc/ChangeLog:
> > 	* Makefile.in (OBJS): Add errors.o, read-md.o, read-rtl.o,
> > 	read-rtl-function.o, and selftest-rtl.o.
> 
> > 	* cfgexpand.c (pass_expand::execute): Move stack
> > initializations
> > 	to rtl_data::init_stack_alignment and call it.  Pass "true"
> > 	for new "emit_insns" param of expand_function_start.
> > 	* emit-rtl.c (gen_reg_rtx): Move regno_pointer_align and
> > 	regno_reg_rtx resizing logic to...
> > 	(emit_status::ensure_regno_capacity): ...this new method.
> > 	(init_emit): Allocate regno_reg_rtx using ggc_cleared_vec_alloc
> > 	rather than ggc_vec_alloc.
> > 	(rtl_data::init_stack_alignment): New method.
> > 	(get_insn_by_uid): New function.
> > 	* emit-rtl.h (rtl_data::init_stack_alignment): New method.
> > 	* errors.c: Use consistent pattern for bconfig.h vs config.h
> > 	includes.
> > 	(progname): Wrap with #ifdef GENERATOR_FILE.
> > 	(error): Likewise.  Add "error: " to message.
> > 	(fatal): Likewise.
> > 	(internal_error): Likewise.
> > 	(trim_filename): Likewise.
> > 	(fancy_abort): Likewise.
> > 	* errors.h (struct file_location): Move here from read-md.h.
> > 	(file_location::file_location): Likewise.
> > 	(error_at): New decl.
> > 	* function-tests.c (selftest::verify_three_block_rtl_cfg):
> > Remove
> > 	"static".
> > 	* function.c (instantiate_decls): Guard call to
> > 	instantiate_decls_1 with if (DECL_INITIAL (fndecl)).
> > 	(expand_function_start): Add param "emit_insns", and use it to
> > 	guard the various gen/emit calls.
> > 	* function.h (emit_status::ensure_regno_capacity): New method.
> > 	(expand_function_start): Add bool param to decl.
> > 	* gensupport.c (gen_reader::gen_reader): Add NULL for new
> > policy
> > 	param of rtx_reader ctor.
> > 	* print-rtl.c (print_rtx): Print "(nil)" rather than an empty
> > 	string for NULL strings.  Print "(nil)" for NULL basic blocks.
> > 	* read-md.c (read_skip_construct): Provide forward decl.
> > 	(read_skip_spaces): Support '/'.
> > 	(require_char): New function.
> > 	(require_word_ws): New function.
> > 	(peek_char): New function.
> > 	(read_name): Rename to...
> > 	(read_name_1): ...this new static function, adding "out_loc"
> > param,
> > 	and converting "missing name or number" to returning false,
> > rather
> > 	than failing.
> > 	(read_name): Reimplement in terms of read_name_1.
> > 	(read_name_or_nil): New function.
> > 	(read_string): Handle "(nil)" by returning NULL.  */
> > 	(rtx_reader::rtx_reader): Add rtl_reader_policy * param, using
> > 	it to initialize m_policy.
> > 	(rtx_reader::~rtx_reader): Free m_base_dir.  Clean up global
> > data.
> > 	* read-md.h (struct file_location): Move to errors.h.
> > 	(file_location::file_location): Likewise.
> > 	Include errors.h.
> > 	(class regno_remapper): New class.
> > 	(struct rtl_reader_policy): New struct.
> > 	(rtx_reader::rtx_reader): Add rtl_reader_policy * param.
> > 	(rtx_reader::add_fixup_insn_uid): New vfunc.
> > 	(rtx_reader::add_fixup_bb): New vfunc.
> > 	(rtx_reader::add_fixup_note_insn_basic_block): New vfunc.
> > 	(rtx_reader::add_fixup_source_location): New vfunc.
> > 	(rtx_reader::add_fixup_jump_label): New vfunc.
> > 	(rtx_reader::add_fixup_expr): New vfunc.
> > 	(rtx_reader::remap_regno): New method.
> > 	(rtx_reader::m_policy): New field.
> > 	(noop_reader::noop_reader): Add NULL for new policy param of
> > 	rtx_reader ctor.
> > 	(peek_char): New decl.
> > 	(require_char): New decl.
> > 	(require_word_ws): New decl.
> > 	(read_name): Convert return type from void to file_location.
> > 	(read_name_or_nil): New decl.
> > 	* read-rtl-function.c: New file.
> > 	* read-rtl-function.h: New file.
> > 	* read-rtl.c: Potentially include config.h rather than
> > bconfig.h.
> > 	For host, include function.h and emit-rtl.h.
> > 	(apply_subst_iterator): Wrap with #ifdef GENERATOR_FILE.
> > 	(bind_subst_iter_and_attr): Likewise.
> > 	(add_condition_to_string): Likewise.
> > 	(add_condition_to_rtx): Likewise.
> > 	(apply_attribute_uses): Likewise.
> > 	(add_current_iterators): Likewise.
> > 	(apply_iterators): Likewise.
> > 	(initialize_iterators): Guard usage of apply_subst_iterator
> > with
> > 	#ifdef GENERATOR_FILE.
> > 	(read_conditions): Wrap with #ifdef GENERATOR_FILE.
> > 	(read_mapping): Likewise.
> > 	(add_define_attr_for_define_subst): Likewise.
> > 	(add_define_subst_attr): Likewise.
> > 	(read_subst_mapping): Likewise.
> > 	(check_code_iterator): Likewise.
> > 	(read_rtx): Likewise.  Move one-time initialization logic to...
> > 	(one_time_initialization): New function.
> > 	(parse_reg_note_name): New function.
> > 	(parse_note_insn_name): New function.
> > 	(maybe_read_location): New function.
> > 	(read_until): New function.
> > 	(strip_trailing_whitespace): New function.
> > 	(read_flags): New function.
> > 	(regno_remapper::get_effective_regno): New method.
> > 	(rtx_reader::remap_regno): New method.
> > 	(read_rtx_code): Remove "static".  Initialize "iterator" to
> > NULL.
> > 	Call one_time_initialization.  Wrap iterator lookup within
> > 	#ifdef GENERATOR_FILE.  Add parsing support for RTL dumps,
> > 	mirroring the special-cases in print_rtx, by calling
> > 	read_flags, reading SYMBOL_REF data, REG_NOTE names,
> > 	INSN_UID values, note-specific data, basic block IDs,
> > 	jump labels, hexdump values of wide ints, REG_EXPR, MEM_EXPR,
> > 	skipping recognized insn names, remapping register numbers.
> > 	When on host, reallocate XSTR and XTMPL fields in the GC
> > -managed
> > 	heap.
> > 	(lookup_global_register): New function.
> > 	(consolidate_reg): New function.
> > 	(consolidate_singletons): New function.
> > 	(read_nested_rtx): Call consolidate_singletons.
> > 	* rtl.h (read_rtx): Wrap decl with #ifdef GENERATOR_FILE.
> > 	(read_rtx_code): New decl.
> > 	* selftest-rtl.c: New file.
> > 	* selftest-rtl.h: New file.
> > 	* selftest-run-tests.c (selftest::run_tests): Run
> > 	read_rtl_function_c_tests.
> > 	* selftest.h  (selftest::read_rtl_function_c_tests): New decl.
> > 	* tree-dfa.c (ssa_default_def): Return NULL_TREE for rtl
> > function
> > 	dumps.
> So I see a couple conceptual things going on here.
> 
> First is initialization/finalization/state handling and various
> fallout 
> items.  Essentially it encompasses all changes that we can make a
> case 
> are useful cleanups and should be handled independently.

I think you've described patch 1 of the kit :)

> Second is all the grunt work necessary to suck in a RTL reader into
> the 
> target's cc1.  The Makefile.in changes, all the GENERATOR_FILE stuff,
> and of course the new rtx_reader class, regno_mapper and the like.
> 
> I think that'll allow us to spend more time looking at the raw
> mechanics 
> of how to pull in an RTL reader into cc1.
> 
> Jeff