This patch rewrites the old VEC macro-based interface into a new one

based on the template class 'vec'.  The user-visible changes are
described in http://gcc.gnu.org/wiki/cxx-conversion/cxx-vec.

I have tested the patch pretty extensively:

- Regular bootstraps on x86_64, ppc, ia64, sparc and hppa.
- Bootstraps with --enable-checking=release
- Bootstraps with --enable-checking=gc,gcac
- Basic builds on all targets (using contrib/config-list.mk).

We no longer access the vectors via VEC_* macros.  The pattern is
"VEC_operation (T, A, V, args)" becomes "V.operation (args)".

The only thing I could not do is create proper ctors and dtors for the
vec class.  Since these vectors are stored in unions, we
have to keep them as PODs (C++03 does not allow non-PODs in unions).

This means that creation and destruction must be explicit.  There is a
new method vec<type, allocation, layout>::create() and another vec<type,
allocation, layout>::destroy() to allocate the internal vector.

For vectors that must be pointers, there is a family of free functions
that implement the operations that need to tolerate NULL vectors.
These functions all start with the prefix 'vec_safe_'.  See the wiki
page for details.

The gengtype change removes the special handling for VEC() that used
to exist in gengtype. Additionally, it allows gengtype to recognize
templates of more than one argument and introduces the concept of an
undefined type (useful for template arguments that may or may not be
types).

When a TYPE_UNDEFINED is reached, gengtype will ignore it if it
happens inside a type marked with GTY((user)).  Otherwise, it will
emit an error.

Finally, gengtype rejects root types marked GTY((user)) that are not
first class pointers.

2012-11-16  Diego Novillo  <dnovillo@google.com>

	VEC API overhaul (http://gcc.gnu.org/wiki/cxx-conversion/cxx-vec)

	* vec.c (register_overhead): Convert it into
	member function of vec_prefix.
	(release_overhead): Likewise.
	(calculate_allocation): Likewise.
	(vec_heap_free): Remove.
	(vec_gc_o_reserve_1): Remove.
	(vec_heap_o_reserve_1): Remove.
	(vec_stack_o_reserve_1): Remove.
	(vec_stack_o_reserve_exact): Remove.
	(register_stack_vec): New.
	(stack_vec_register_index): New.
	(unregister_stack_vec): New.
	(vec_assert_fail): Remove.
	* vec.h: Conditionally include ggc.h.  Document conditional
	hackery.
	Update top-level documentation.
	(ALONE_VEC_CHECK_INFO): Remove.
	(VEC_CHECK_INFO): Remove.
	(ALONE_VEC_CHECK_DECL): Remove.
	(VEC_CHECK_DECL): Remove.
	(ALONE_VEC_CHECK_PASS): Remove.
	(VEC_CHECK_PASS): Remove.
	(VEC_ASSERT): Remove.
	(vec_prefix): Add friends va_gc, va_gc_atomic, va_heap and
	va_stack.
	Mark fields alloc_ and num_ as protected.
	(struct vec_t): Remove.  Remove all function members.
	(struct vl_embed): Declare.
	(struct vl_ptr): Declare.
	(free): Remove.
	(reserve_exact): Remove.
	(reserve): Remove.
	(safe_splice): Remove.
	(safe_push): Remove.
	(safe_grow): Remove.
	(safe_grow_cleared): Remove.
	(safe_insert): Remove.
	(DEF_VEC_I): Remove.
	(DEF_VEC_ALLOC_I): Remove.
	(DEF_VEC_P): Remove.
	(DEF_VEC_ALLOC_P): Remove.
	(DEF_VEC_O): Remove.
	(DEF_VEC_ALLOC_O): Remove.
	(DEF_VEC_ALLOC_P_STACK): Remove.
	(DEF_VEC_ALLOC_O_STACK): Remove.
	(DEF_VEC_ALLOC_I_STACK): Remove.
	(DEF_VEC_A): Remove.
	(DEF_VEC_ALLOC_A): Remove.
	(vec_stack_p_reserve_exact_1): Remove.
	(vec_stack_o_reserve): Remove.
	(vec_stack_o_reserve_exact): Remove.
	(VEC_length): Remove.
	(VEC_empty): Remove.
	(VEC_address): Remove.
	(vec_address): Remove.
	(VEC_last): Remove.
	(VEC_index): Remove.
	(VEC_iterate): Remove.
	(VEC_embedded_size): Remove.
	(VEC_embedded_init): Remove.
	(VEC_free): Remove.
	(VEC_copy): Remove.
	(VEC_space): Remove.
	(VEC_reserve): Remove.
	(VEC_reserve_exact): Remove.
	(VEC_splice): Remove.
	(VEC_safe_splice): Remove.
	(VEC_quick_push): Remove.
	(VEC_safe_push): Remove.
	(VEC_pop): Remove.
	(VEC_truncate): Remove.
	(VEC_safe_grow): Remove.
	(VEC_replace): Remove.
	(VEC_quick_insert): Remove.
	(VEC_safe_insert): Remove.
	(VEC_ordered_remove): Remove.
	(VEC_unordered_remove): Remove.
	(VEC_block_remove): Remove.
	(VEC_lower_bound): Remove.
	(VEC_alloc): Remove.
	(VEC_qsort): Remove.

	(va_heap): Declare.
	(va_heap::default_layout): New typedef to vl_ptr.
	(va_heap::reserve): New.
	(va_heap::release): New.
	(va_gc): Declare.
	(va_gc::default_layout): New typedef to vl_embed.
	(va_gc::reserve): New.
	(va_gc::release): New.
	(va_gc_atomic): Declare.  Inherit from va_gc.
	(va_stack): Declare.
	(va_stack::default_layout): New typedef to vl_ptr.
	(va_stack::alloc): New.
	(va_stack::reserve): New.
	(va_stack::release): New.
	(register_stack_vec): Declare.
	(stack_vec_register_index): Declare.
	(unregister_stack_vec): Declare.

	(vec<T, A = va_heap, L = typename A::default_layout>): Declare
	empty vec template.
	(vec<T, A, vl_embed>): Partial specialization for embedded
	layout.
	(vec<T, A, vl_embed>::allocated): New.
	(vec<T, A, vl_embed>::length): New.
	(vec<T, A, vl_embed>::is_empty): New.
	(vec<T, A, vl_embed>::address): New.
	(vec<T, A, vl_embed>::operator[]): New.
	(vec<T, A, vl_embed>::last New.
	(vec<T, A, vl_embed>::space): New.
	(vec<T, A, vl_embed>::iterate): New.
	(vec<T, A, vl_embed>::iterate): New.
	(vec<T, A, vl_embed>::copy): New.
	(vec<T, A, vl_embed>::splice): New.
	(vec<T, A, vl_embed>::quick_push New.
	(vec<T, A, vl_embed>::pop New.
	(vec<T, A, vl_embed>::truncate): New.
	(vec<T, A, vl_embed>::quick_insert): New.
	(vec<T, A, vl_embed>::ordered_remove): New.
	(vec<T, A, vl_embed>::unordered_remove): New.
	(vec<T, A, vl_embed>::block_remove): New.
	(vec<T, A, vl_embed>::qsort): New.
	(vec<T, A, vl_embed>::lower_bound): New.
	(vec<T, A, vl_embed>::embedded_size): New.
	(vec<T, A, vl_embed>::embedded_init): New.
	(vec<T, A, vl_embed>::quick_grow): New.
	(vec<T, A, vl_embed>::quick_grow_cleared): New.
	(vec_safe_space): New.
	(vec_safe_length): New.
	(vec_safe_address): New.
	(vec_safe_is_empty): New.
	(vec_safe_reserve): New.
	(vec_safe_reserve_exact): New.
	(vec_alloc): New.
	(vec_free): New.
	(vec_safe_grow): New.
	(vec_safe_grow_cleared): New.
	(vec_safe_iterate): New.
	(vec_safe_push): New.
	(vec_safe_insert): New.
	(vec_safe_truncate): New.
	(vec_safe_copy): New.
	(vec_safe_splice): New.

	(vec<T, A, vl_ptr>): New partial specialization for the space
	efficient layout.
	(vec<T, A, vl_ptr>::exists): New.
	(vec<T, A, vl_ptr>::is_empty): New.
	(vec<T, A, vl_ptr>::length): New.
	(vec<T, A, vl_ptr>::address): New.
	(vec<T, A, vl_ptr>::operator[]): New.
	(vec<T, A, vl_ptr>::operator!=): New.
	(vec<T, A, vl_ptr>::operator==): New.
	(vec<T, A, vl_ptr>::last): New.
	(vec<T, A, vl_ptr>::space): New.
	(vec<T, A, vl_ptr>::iterate): New.
	(vec<T, A, vl_ptr>::copy): New.
	(vec<T, A, vl_ptr>::reserve): New.
	(vec<T, A, vl_ptr>::reserve_exact): New.
	(vec<T, A, vl_ptr>::splice): New.
	(vec<T, A, vl_ptr>::safe_splice): New.
	(vec<T, A, vl_ptr>::quick_push): New.
	(vec<T, A, vl_ptr>::safe_push): New.
	(vec<T, A, vl_ptr>::pop): New.
	(vec<T, A, vl_ptr>::truncate): New.
	(vec<T, A, vl_ptr>::safe_grow): New.
	(vec<T, A, vl_ptr>::safe_grow_cleared): New.
	(vec<T, A, vl_ptr>::quick_grow): New.
	(vec<T, A, vl_ptr>::quick_grow_cleared): New.
	(vec<T, A, vl_ptr>::quick_insert): New.
	(vec<T, A, vl_ptr>::safe_insert): New.
	(vec<T, A, vl_ptr>::ordered_remove): New.
	(vec<T, A, vl_ptr>::unordered_remove): New.
	(vec<T, A, vl_ptr>::block_remove): New.
	(vec<T, A, vl_ptr>::qsort): New.
	(vec<T, A, vl_ptr>::lower_bound): New.
	(vec_stack_alloc): Define.
	(FOR_EACH_VEC_SAFE_ELT): Define.
	* vecir.h: Remove.  Update all users.
	* vecprim.h: Remove.  Update all users.
	Move uchar to coretypes.h.

	* Makefile.in (VEC_H): Add $(GGC_H).
	Remove vecir.h and vecprim.h dependencies everywhere.

2012-11-16  Diego Novillo  <dnovillo@google.com>

	* gengtype-lex.l (VEC): Remove.
	Add characters in the set [\!\>\.-].
	* gengtype-parse.c (token_names): Remove "VEC".
	(require_template_declaration): Remove handling of VEC_TOKEN.
	(type): Likewise.
	Call create_user_defined_type when parsing GTY((user)).
	* gengtype-state.c (type_lineloc): handle TYPE_UNDEFINED.
	(write_state_undefined_type): New.
	(write_state_type): Call write_state_undefined_type for
	TYPE_UNDEFINED.
	(read_state_type): Call read_state_undefined_type for
	TYPE_UNDEFINED.
	* gengtype.c (dbgprint_count_type_at): Handle TYPE_UNDEFINED.
	(create_user_defined_type): Make extern.
	(type_for_name): Factor out of resolve_typedef.
	(create_undefined_type): New
	(resolve_typedef): Call it when we cannot find a previous
	typedef and the type is not a template.
	(find_structure): Accept TYPE_UNDEFINED.
	(set_gc_used_type): Add argument ALLOWED_UNDEFINED_TYPES,
	default to false.
	Emit an error for TYPE_UNDEFINED unless LEVEL is GC_UNUSED or
	ALLOWED_UNDEFINED_TYPES is set.
	Set ALLOWED_UNDEFINED_TYPES to true for TYPE_USER_STRUCT.
	(filter_type_name): Accept templates with more than one
	argument.
	(output_mangled_typename): Handle TYPE_UNDEFINED
	(walk_type): Likewise.
	(write_types_process_field): Likewise.
	(write_func_for_structure): If CHAIN_NEXT is set, ORIG_S
	should not be a user-defined type.
	(write_types_local_user_process_field): Handle TYPE_ARRAY,
	TYPE_NONE and TYPE_UNDEFINED.
	(write_types_local_process_field): Likewise.
	(contains_scalar_p): Return 0 for TYPE_USER_STRUCT.
	(write_root): Reject user-defined types that are not pointers.
	Handle TYPE_NONE, TYPE_UNDEFINED, TYPE_UNION, TYPE_LANG_STRUCT
	and TYPE_PARAM_STRUCT.
	(output_typename): Handle TYPE_NONE, TYPE_UNDEFINED, and
	TYPE_ARRAY.
	(dump_typekind): Handle TYPE_UNDEFINED.
	* gengtype.h (enum typekind): Add TYPE_UNDEFINED.
	(create_user_defined_type): Declare.
	(enum gty_token): Remove VEC_TOKEN.

2012-11-16  Diego Novillo  <dnovillo@google.com>

	Adjust for new vec API (http://gcc.gnu.org/wiki/cxx-conversion/cxx-vec)

	* coretypes.h (uchar): Define.
	* alias.c: Use new vec API in vec.h.
	* asan.c: Likewise.
	* attribs.c: Likewise.
	* basic-block.h: Likewise.
	* bb-reorder.c: Likewise.
	* builtins.c: Likewise.
	* calls.c: Likewise.
	* cfg.c: Likewise.
	* cfganal.c: Likewise.
	* cfgcleanup.c: Likewise.
	* cfgexpand.c: Likewise.
	* cfghooks.c: Likewise.
	* cfghooks.h: Likewise.
	* cfgloop.c: Likewise.
	* cfgloop.h: Likewise.
	* cfgloopanal.c: Likewise.
	* cfgloopmanip.c: Likewise.
	* cfgrtl.c: Likewise.
	* cgraph.c: Likewise.
	* cgraph.h: Likewise.
	* cgraphclones.c: Likewise.
	* cgraphunit.c: Likewise.
	* combine.c: Likewise.
	* compare-elim.c: Likewise.
	* coverage.c: Likewise.
	* cprop.c: Likewise.
	* data-streamer.h: Likewise.
	* dbxout.c: Likewise.
	* dce.c: Likewise.
	* df-core.c: Likewise.
	* df-problems.c: Likewise.
	* df-scan.c: Likewise.
	* dominance.c: Likewise.
	* domwalk.c: Likewise.
	* domwalk.h: Likewise.
	* dse.c: Likewise.
	* dwarf2cfi.c: Likewise.
	* dwarf2out.c: Likewise.
	* dwarf2out.h: Likewise.
	* emit-rtl.c: Likewise.
	* except.c: Likewise.
	* except.h: Likewise.
	* expr.c: Likewise.
	* expr.h: Likewise.
	* final.c: Likewise.
	* fold-const.c: Likewise.
	* function.c: Likewise.
	* function.h: Likewise.
	* fwprop.c: Likewise.
	* gcc.c: Likewise.
	* gcse.c: Likewise.
	* genattr.c: Likewise.
	* genattrtab.c: Likewise.
	* genautomata.c: Likewise.
	* genextract.c: Likewise.
	* genopinit.c: Likewise
	* ggc-common.c: Likewise.
	* ggc.h: Likewise.
	* gimple-low.c: Likewise.
	* gimple-ssa-strength-reduction.c: Likewise.
	* gimple-streamer-in.c: Likewise.
	* gimple.c: Likewise.
	* gimple.h: Likewise.
	* gimplify.c: Likewise.
	* graph.c: Likewise.
	* graphds.c: Likewise.
	* graphds.h: Likewise.
	* graphite-blocking.c: Likewise.
	* graphite-clast-to-gimple.c: Likewise.
	* graphite-dependences.c: Likewise.
	* graphite-interchange.c: Likewise.
	* graphite-optimize-isl.c: Likewise.
	* graphite-poly.c: Likewise.
	* graphite-poly.h: Likewise.
	* graphite-scop-detection.c: Likewise.
	* graphite-scop-detection.h: Likewise.
	* graphite-sese-to-poly.c: Likewise.
	* graphite.c: Likewise.
	* godump.c: Likewise.
	* haifa-sched.c: Likewise.
	* hw-doloop.c: Likewise.
	* hw-doloop.h: Likewise.
	* ifcvt.c: Likewise.
	* insn-addr.h: Likewise.
	* ipa-cp.c: Likewise.
	* ipa-inline-analysis.c: Likewise.
	* ipa-inline-transform.c: Likewise.
	* ipa-inline.c: Likewise.
	* ipa-inline.h: Likewise.
	* ipa-prop.c: Likewise.
	* ipa-prop.h: Likewise.
	* ipa-pure-const.c: Likewise.
	* ipa-ref-inline.h: Likewise.
	* ipa-ref.c: Likewise.
	* ipa-ref.h: Likewise.
	* ipa-reference.c: Likewise.
	* ipa-split.c: Likewise.
	* ipa-utils.c: Likewise.
	* ipa-utils.h: Likewise.
	* ipa.c: Likewise.
	* ira-build.c: Likewise.
	* ira-color.c: Likewise.
	* ira-emit.c: Likewise.
	* ira-int.h: Likewise.
	* ira.c: Likewise.
	* loop-invariant.c: Likewise.
	* loop-unroll.c: Likewise.
	* lower-subreg.c: Likewise.
	* lra-lives.c: Likewise.
	* lra.c: Likewise.
	* lto-cgraph.c: Likewise.
	* lto-section-out.c: Likewise.
	* lto-streamer-in.c: Likewise.
	* lto-streamer-out.c: Likewise.
	* lto-streamer.h: Likewise.
	* lto-symtab.c: Likewise.
	* mcf.c: Likewise.
	* modulo-sched.c: Likewise.
	* omp-low.c: Likewise.
	* opts-common.c: Likewise.
	* opts-global.c: Likewise.
	* opts.c: Likewise.
	* opts.h: Likewise.
	* passes.c: Likewise.
	* predict.c: Likewise.
	* print-tree.c: Likewise.
	* profile.c: Likewise.
	* profile.h: Likewise.
	* read-rtl.c: Likewise.
	* ree.c: Likewise.
	* reg-stack.c: Likewise.
	* regrename.c: Likewise.
	* regrename.h: Likewise.
	* reload.c: Likewise.
	* reload.h: Likewise.
	* reload1.c: Likewise.
	* rtl.h: Likewise.
	* sched-deps.c: Likewise.
	* sched-int.h: Likewise.
	* sdbout.c: Likewise.
	* sel-sched-dump.c: Likewise.
	* sel-sched-ir.c: Likewise.
	* sel-sched-ir.h: Likewise.
	* sel-sched.c: Likewise.
	* sese.c: Likewise.
	* sese.h: Likewise.
	* statistics.h: Likewise.
	* stmt.c: Likewise.
	* stor-layout.c: Likewise.
	* store-motion.c: Likewise.
	* tlink.c: Likewise.
	* toplev.c: Likewise.
	* trans-mem.c: Likewise.
	* tree-browser.c: Likewise.
	* tree-call-cdce.c: Likewise.
	* tree-cfg.c: Likewise.
	* tree-cfgcleanup.c: Likewise.
	* tree-chrec.c: Likewise.
	* tree-chrec.h: Likewise.
	* tree-complex.c: Likewise.
	* tree-data-ref.c: Likewise.
	* tree-data-ref.h: Likewise.
	* tree-dfa.c: Likewise.
	* tree-diagnostic.c: Likewise.
	* tree-dump.c: Likewise.
	* tree-eh.c: Likewise.
	* tree-emutls.c: Likewise.
	* tree-flow.h: Likewise.
	* tree-if-conv.c: Likewise.
	* tree-inline.c: Likewise.
	* tree-inline.h: Likewise.
	* tree-into-ssa.c: Likewise.
	* tree-iterator.c: Likewise.
	* tree-loop-distribution.c: Likewise.
	* tree-mudflap.c: Likewise.
	* tree-optimize.c: Likewise.
	* tree-outof-ssa.c: Likewise.
	* tree-parloops.c: Likewise.
	* tree-phinodes.c: Likewise.
	* tree-predcom.c: Likewise.
	* tree-pretty-print.c: Likewise.
	* tree-scalar-evolution.c: Likewise.
	* tree-sra.c: Likewise.
	* tree-ssa-address.c: Likewise.
	* tree-ssa-alias.c: Likewise.
	* tree-ssa-ccp.c: Likewise.
	* tree-ssa-coalesce.c: Likewise.
	* tree-ssa-dce.c: Likewise.
	* tree-ssa-dom.c: Likewise.
	* tree-ssa-forwprop.c: Likewise.
	* tree-ssa-live.c: Likewise.
	* tree-ssa-live.h: Likewise.
	* tree-ssa-loop-im.c: Likewise.
	* tree-ssa-loop-ivcanon.c: Likewise.
	* tree-ssa-loop-ivopts.c: Likewise.
	* tree-ssa-loop-manip.c: Likewise.
	* tree-ssa-loop-niter.c: Likewise.
	* tree-ssa-loop-prefetch.c: Likewise.
	* tree-ssa-math-opts.c: Likewise.
	* tree-ssa-operands.c: Likewise.
	* tree-ssa-phiopt.c: Likewise.
	* tree-ssa-phiprop.c: Likewise.
	* tree-ssa-pre.c: Likewise.
	* tree-ssa-propagate.c: Likewise.
	* tree-ssa-reassoc.c: Likewise.
	* tree-ssa-sccvn.c: Likewise.
	* tree-ssa-sccvn.h: Likewise.
	* tree-ssa-strlen.c: Likewise.
	* tree-ssa-structalias.c: Likewise.
	* tree-ssa-tail-merge.c: Likewise.
	* tree-ssa-threadedge.c: Likewise.
	* tree-ssa-threadupdate.c: Likewise.
	* tree-ssa-uncprop.c: Likewise.
	* tree-ssa-uninit.c: Likewise.
	* tree-ssa.c: Likewise.
	* tree-ssanames.c: Likewise.
	* tree-stdarg.c: Likewise.
	* tree-streamer-in.c: Likewise.
	* tree-streamer-out.c: Likewise.
	* tree-streamer.c: Likewise.
	* tree-streamer.h: Likewise.
	* tree-switch-conversion.c: Likewise.
	* tree-vect-data-refs.c: Likewise.
	* tree-vect-generic.c: Likewise.
	* tree-vect-loop-manip.c: Likewise.
	* tree-vect-loop.c: Likewise.
	* tree-vect-patterns.c: Likewise.
	* tree-vect-slp.c: Likewise.
	* tree-vect-stmts.c: Likewise.
	* tree-vectorizer.c: Likewise.
	* tree-vectorizer.h: Likewise.
	* tree-vrp.c: Likewise.
	* tree.c: Likewise.
	* tree.h: Likewise.
	* value-prof.c: Likewise.
	* value-prof.h: Likewise.
	* var-tracking.c: Likewise.
	* varasm.c: Likewise.
	* varpool.c: Likewise.
	* vmsdbgout.c: Likewise.
	* config/bfin/bfin.c: Likewise.
	* config/c6x/c6x.c: Likewise.
	* config/darwin.c: Likewise.
	* config/i386/i386.c: Likewise.
	* config/ia64/ia64.c: Likewise.
	* config/mep/mep.c: Likewise.
	* config/mips/mips.c: Likewise.
	* config/pa/pa.c: Likewise.
	* config/rs6000/rs6000-c.c: Likewise.
	* config/rs6000/rs6000.c: Likewise.
	* config/rx/rx.c: Likewise.
	* config/spu/spu-c.c: Likewise.
	* config/vms/vms.c: Likewise.
	* config/vxworks.c: Likewise.
	* config/epiphany/resolve-sw-modes.c: Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@193595 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 2 insertions, 4 deletions

diff --git a/gcc/domwalk.h b/gcc/domwalk.h
index 63aeec233a3..e0c11f65d72 100644
--- a/gcc/domwalk.h
+++ b/gcc/domwalk.h
@@ -19,8 +19,6 @@ along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
 typedef void *void_p;
-DEF_VEC_P(void_p);
-DEF_VEC_ALLOC_P(void_p,heap);
 
 /* This is the main data structure for the dominator walker.  It provides
    the callback hooks as well as a convenient place to hang block local
@@ -58,7 +56,7 @@ struct dom_walk_data
   /* Stack of any data we need to keep on a per-block basis.
 
      If you have no local data, then BLOCK_DATA_STACK will be NULL.  */
-  VEC(void_p,heap) *block_data_stack;
+  vec<void_p> block_data_stack;
 
   /* Size of the block local data.   If this is zero, then it is assumed
      you have no local data and thus no BLOCK_DATA_STACK as well.  */
@@ -68,7 +66,7 @@ struct dom_walk_data
      information/data outside domwalk.c.  */
 
   /* Stack of available block local structures.  */
-  VEC(void_p,heap) *free_block_data;
+  vec<void_p> free_block_data;
 };
 
 void walk_dominator_tree (struct dom_walk_data *, basic_block);