[SFN] not-quite-boilerplate changes in preparation to introduce nonbind markers

This patch adjusts numerous parts of the compiler that would
malfunction should they find debug markers at points where they may be
introduced.  The changes purport to allow the compiler to pass
bootstrap-debug-lean (-fcompare-debug in stage3) at various
optimization levels, as well as bootstrap-debug-lib (-fcompare-debug
for target libraries), even after the compiler is changed so that
debug markers are introduced in code streams at spots where earlier
debug stmts, insns and notes wouldn't normally appear.

This patch depends on an earlier SFN boilerplate patch, and on another
SFN patch that introduces new RTL insn-walking functions.

for  gcc/ChangeLog

	* cfgcleanup.c (delete_unreachable_blocks): Use alternate
	block removal order if MAY_HAVE_DEBUG_BIND_INSNS.
	* cfgexpand.c (label_rtx_for_bb): Skip debug insns.
	* cfgrtl.c (try_redirect_by_replacing_jump): Skip debug insns.
	(rtl_tidy_fallthru_edge): Likewise.
	(rtl_verify_fallthru): Likewise.
	(rtl_verify_bb_layout): Likewise.
	(skip_insns_after_block): Likewise.
	(duplicate_insn_chain): Use DEBUG_BIND_INSN_P.
	* dwarf2out.c: Include print-rtl.h.
	(dwarf2out_next_real_insn): New.
	(dwarf2out_var_location): Call it.  Disregard begin stmt markers.
	Dump debug binds in asm comments.
	* gimple-iterator.c (gimple_find_edge_insert_loc): Skip debug stmts.
	* gimple-iterator.h (gsi_start_bb_nondebug): Remove; adjust
	callers to use gsi_start_nondebug_bb instead.
	(gsi_after_labels): Skip gimple debug stmts.
	(gsi_start_nondebug): New.
	* gimple-loop-interchange.c (find_deps_in_bb_for_stmt): Adjust.
	(proper_loop_form_for_interchange): Adjust.
	* gimple-low.c (gimple_seq_may_fallthru): Take last nondebug stmt.
	* gimple.h (gimple_seq_last_nondebug_stmt): New.
	* gimplify.c (last_stmt_in_scope): Skip debug stmts.
	(collect_fallthrough_labels): Likewise.
	(should_warn_for_implicit_fallthrough): Likewise.
	(warn_implicit_fallthrough_r): Likewise.
	(expand_FALLTHROUGH_r): Likewise.
	* graphite-isl-ast-to-gimple.c (gsi_insert_earliest): Adjust.
	(graphite_copy_stmts_from_block): Skip nonbind markers.
	* haifa-sched.c (sched_extend_bb): Skip debug insns.
	* ipa-icf-gimple.c (func_checker::compare_bb): Adjust.
	* jump.c (clean_barriers): Skip debug insns.
	* omp-expand.c (expand_parallel_call): Skip debug insns.
	(expand_task_call): Likewise.
	(remove_exit_barrier): Likewise.
	(expand_omp_taskreg): Likewise.
	(expand_omp_for_init_counts): Likewise.
	(expand_omp_for_generic): Likewise.
	(expand_omp_for_static_nochunk): Likewise.
	(expand_omp_for_static_chunk): Likewise.
	(expand_omp_simd): Likewise.
	(expand_omp_taskloop_for_outer): Likewise.
	(expand_omp_taskloop_for_inner): Likewise.
	(expand_oacc_for): Likewise.
	(expand_omp_sections): Likewise.
	(expand_omp_single): Likewise.
	(expand_omp_synch): Likewise.
	(expand_omp_atomic_load): Likewise.
	(expand_omp_atomic_store): Likewise.
	(expand_omp_atomic_fetch_op): Likewise.
	(expand_omp_atomic_pipeline): Likewise.
	(expand_omp_atomic_mutex): Likewise.
	(expand_omp_target): Likewise.
	(grid_expand_omp_for_loop): Likewise.
	(grid_expand_target_grid_body): Likewise.
	(build_omp_regions_1): Likewise.
	* omp-low.c (check_combined_parallel): Skip debug stmts.
	* postreload.c (fixup_debug_insns): Skip nonbind debug insns.
	* regcprop.c (find_oldest_value_reg): Ensure REGNO is not a pseudo.
	* sese.c (sese_trivially_empty_bb_p): Call is_gimple_debug in
	test.
	* tree-cfg.c (make_blobs_1): Skip debug stmts.
	(make_edges): Likewise.
	(cleanup_dead_labels): Likewise.
	(gimple_can_merge_blocks_p): Likewise.
	(stmt_starts_bb_p): Likewise.
	(gimple_block_label): Likewise.
	(gimple_redirect_edge_and_branch): Likewise.
	* tree-cfgcleanup.c (remove_forwarder_block): Rearrange skipping
	of debug stmts.
	(execute_cleanup_cfg_post_optimizing): Dump enumerated decls with
	TDF_SLIM.
	* tree-pretty-print (print_declaration): Omit initializer in slim
	dumps.
	* tree-ssa-dce.c (mark_stmt_if_obviously_necessary): Mark begin stmt
	markers.
	(eliminate_unnecessary_stmts): Stabilize block removal order.
	* tree-ssa-tail-merge.c (find_duplicate): Skip debug stmts.
	* var-tracking.c (get_first_insn): New.
	(vt_emit_notes): Call it.
	(vt_initialize): Walk any insns before the first BB.
	(delete_debug_insns): Likewise.

From-SVN: r255566

1 files changed, 36 insertions, 2 deletions

diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 876e53f..82c9ccf 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -83,6 +83,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "toplev.h"
 #include "md5.h"
 #include "tree-pretty-print.h"
+#include "print-rtl.h"
 #include "debug.h"
 #include "common/common-target.h"
 #include "langhooks.h"
@@ -26210,6 +26211,22 @@ static bool maybe_at_text_label_p = true;
 /* One above highest N where .LVLN label might be equal to .Ltext0 label.  */
 static unsigned int first_loclabel_num_not_at_text_label;
 
+/* Look ahead for a real insn, or for a begin stmt marker.  */
+
+static rtx_insn *
+dwarf2out_next_real_insn (rtx_insn *loc_note)
+{
+  rtx_insn *next_real = NEXT_INSN (loc_note);
+
+  while (next_real)
+    if (INSN_P (next_real))
+      break;
+    else
+      next_real = NEXT_INSN (next_real);
+
+  return next_real;
+}
+
 /* Called by the final INSN scan whenever we see a var location.  We
    use it to drop labels in the right places, and throw the location in
    our lookup table.  */
@@ -26258,7 +26275,7 @@ dwarf2out_var_location (rtx_insn *loc_note)
 		  loc_note = NULL;
 		  var_loc_p = false;
 
-		  next_real = next_real_insn (call_insn);
+		  next_real = dwarf2out_next_real_insn (call_insn);
 		  next_note = NULL;
 		  cached_next_real_insn = NULL;
 		  goto create_label;
@@ -26288,11 +26305,12 @@ dwarf2out_var_location (rtx_insn *loc_note)
       || next_note->deleted ()
       || ! NOTE_P (next_note)
       || (NOTE_KIND (next_note) != NOTE_INSN_VAR_LOCATION
+	  && NOTE_KIND (next_note) != NOTE_INSN_BEGIN_STMT
 	  && NOTE_KIND (next_note) != NOTE_INSN_CALL_ARG_LOCATION))
     next_note = NULL;
 
   if (! next_real)
-    next_real = next_real_insn (loc_note);
+    next_real = dwarf2out_next_real_insn (loc_note);
 
   if (next_note)
     {
@@ -26451,6 +26469,22 @@ create_label:
       newloc->label = last_postcall_label;
     }
 
+  if (var_loc_p && flag_debug_asm)
+    {
+      const char *name = NULL, *sep = " => ", *patstr = NULL;
+      if (decl && DECL_NAME (decl))
+	name = IDENTIFIER_POINTER (DECL_NAME (decl));
+      if (NOTE_VAR_LOCATION_LOC (loc_note))
+	patstr = str_pattern_slim (NOTE_VAR_LOCATION_LOC (loc_note));
+      else
+	{
+	  sep = " ";
+	  patstr = "RESET";
+	}
+      fprintf (asm_out_file, "\t%s DEBUG %s%s%s\n", ASM_COMMENT_START,
+	       name, sep, patstr);
+    }
+
   last_var_location_insn = next_real;
   last_in_cold_section_p = in_cold_section_p;
 }