[gcc r12-6913] Make graph dumping work for fn != cfun

[gcc r12-6913] Make graph dumping work for fn != cfun

[Richard Biener]

https://gcc.gnu.org/g:b500d2591ea0080459d5dee127f63c010530f6b6

commit r12-6913-gb500d2591ea0080459d5dee127f63c010530f6b6
Author: Richard Biener <rguenther@suse.de>
Date:   Fri Jan 28 10:28:39 2022 +0100

    Make graph dumping work for fn != cfun
    
    The following makes dumping of a function as graph work as intended
    when specifying a function other than cfun.  Unfortunately the loop
    and the dominance APIs are not set up to work for other functions
    than cfun so you won't get any fancy loop dumps but the non-loop
    dump works up to reaching mark_dfs_back_edges which I trivially made
    function aware and adjusted current callers with a wrapper.
    
    With all this, doing dot-fn id->src_cfun from the debugger when
    debugging inlining works.  Previously you got a strange mix of
    the src and dest functions visualized ;)
    
    2022-01-28  Richard Biener  <rguenther@suse.de>
    
            * cfganal.h (mark_dfs_back_edges): Provide API with struct
            function argument.
            * cfganal.cc (mark_dfs_back_edges): Take a struct function
            to work on, add a wrapper passing cfun.
            * graph.cc (draw_cfg_nodes_no_loops): Replace stray cfun
            uses with fun which is already passed.
            (draw_cfg_edges): Likewise.
            (draw_cfg_nodes_for_loop): Do not use draw_cfg_nodes_for_loop
            for fun != cfun.

Diff:
---
 gcc/cfganal.cc | 28 +++++++++++++++++-----------
 gcc/cfganal.h  |  1 +
 gcc/graph.cc   | 15 ++++++++-------
 3 files changed, 26 insertions(+), 18 deletions(-)

diff --git a/gcc/cfganal.cc b/gcc/cfganal.cc
index e570d27768b..79c627a1716 100644
--- a/gcc/cfganal.cc
+++ b/gcc/cfganal.cc
@@ -58,7 +58,7 @@ private:
    and heavily borrowed from pre_and_rev_post_order_compute.  */
 
 bool
-mark_dfs_back_edges (void)
+mark_dfs_back_edges (struct function *fun)
 {
   int *pre;
   int *post;
@@ -67,20 +67,20 @@ mark_dfs_back_edges (void)
   bool found = false;
 
   /* Allocate the preorder and postorder number arrays.  */
-  pre = XCNEWVEC (int, last_basic_block_for_fn (cfun));
-  post = XCNEWVEC (int, last_basic_block_for_fn (cfun));
+  pre = XCNEWVEC (int, last_basic_block_for_fn (fun));
+  post = XCNEWVEC (int, last_basic_block_for_fn (fun));
 
   /* Allocate stack for back-tracking up CFG.  */
-  auto_vec<edge_iterator, 20> stack (n_basic_blocks_for_fn (cfun) + 1);
+  auto_vec<edge_iterator, 20> stack (n_basic_blocks_for_fn (fun) + 1);
 
   /* Allocate bitmap to track nodes that have been visited.  */
-  auto_sbitmap visited (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (fun));
 
   /* None of the nodes in the CFG have been visited yet.  */
   bitmap_clear (visited);
 
   /* Push the first edge on to the stack.  */
-  stack.quick_push (ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs));
+  stack.quick_push (ei_start (ENTRY_BLOCK_PTR_FOR_FN (fun)->succs));
 
   while (!stack.is_empty ())
     {
@@ -94,8 +94,8 @@ mark_dfs_back_edges (void)
       ei_edge (ei)->flags &= ~EDGE_DFS_BACK;
 
       /* Check if the edge destination has been visited yet.  */
-      if (dest != EXIT_BLOCK_PTR_FOR_FN (cfun) && ! bitmap_bit_p (visited,
-								  dest->index))
+      if (dest != EXIT_BLOCK_PTR_FOR_FN (fun) && ! bitmap_bit_p (visited,
+								 dest->index))
 	{
 	  /* Mark that we have visited the destination.  */
 	  bitmap_set_bit (visited, dest->index);
@@ -112,14 +112,14 @@ mark_dfs_back_edges (void)
 	}
       else
 	{
-	  if (dest != EXIT_BLOCK_PTR_FOR_FN (cfun)
-	      && src != ENTRY_BLOCK_PTR_FOR_FN (cfun)
+	  if (dest != EXIT_BLOCK_PTR_FOR_FN (fun)
+	      && src != ENTRY_BLOCK_PTR_FOR_FN (fun)
 	      && pre[src->index] >= pre[dest->index]
 	      && post[dest->index] == 0)
 	    ei_edge (ei)->flags |= EDGE_DFS_BACK, found = true;
 
 	  if (ei_one_before_end_p (ei)
-	      && src != ENTRY_BLOCK_PTR_FOR_FN (cfun))
+	      && src != ENTRY_BLOCK_PTR_FOR_FN (fun))
 	    post[src->index] = postnum++;
 
 	  if (!ei_one_before_end_p (ei))
@@ -135,6 +135,12 @@ mark_dfs_back_edges (void)
   return found;
 }
 
+bool
+mark_dfs_back_edges (void)
+{
+  return mark_dfs_back_edges (cfun);
+}
+
 /* Find unreachable blocks.  An unreachable block will have 0 in
    the reachable bit in block->flags.  A nonzero value indicates the
    block is reachable.  */
diff --git a/gcc/cfganal.h b/gcc/cfganal.h
index 386cfbf211f..ac637de2b5a 100644
--- a/gcc/cfganal.h
+++ b/gcc/cfganal.h
@@ -49,6 +49,7 @@ private:
   bitmap_obstack m_bitmaps;
 };
 
+extern bool mark_dfs_back_edges (struct function *);
 extern bool mark_dfs_back_edges (void);
 extern void find_unreachable_blocks (void);
 extern void verify_no_unreachable_blocks (void);
diff --git a/gcc/graph.cc b/gcc/graph.cc
index 9990c8eccfd..bc29862fcad 100644
--- a/gcc/graph.cc
+++ b/gcc/graph.cc
@@ -169,14 +169,14 @@ draw_cfg_nodes_no_loops (pretty_printer *pp, struct function *fun)
   int *rpo = XNEWVEC (int, n_basic_blocks_for_fn (fun));
   int i, n;
 
-  auto_sbitmap visited (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (fun));
   bitmap_clear (visited);
 
   n = pre_and_rev_post_order_compute_fn (fun, NULL, rpo, true);
   for (i = n_basic_blocks_for_fn (fun) - n;
        i < n_basic_blocks_for_fn (fun); i++)
     {
-      basic_block bb = BASIC_BLOCK_FOR_FN (cfun, rpo[i]);
+      basic_block bb = BASIC_BLOCK_FOR_FN (fun, rpo[i]);
       draw_cfg_node (pp, fun->funcdef_no, bb);
       bitmap_set_bit (visited, bb->index);
     }
@@ -248,7 +248,8 @@ draw_cfg_nodes_for_loop (pretty_printer *pp, int funcdef_no,
 static void
 draw_cfg_nodes (pretty_printer *pp, struct function *fun)
 {
-  if (loops_for_fn (fun))
+  /* ???  The loop and dominance APIs are dependent on fun == cfun.  */
+  if (fun == cfun && loops_for_fn (fun))
     draw_cfg_nodes_for_loop (pp, fun->funcdef_no, get_loop (fun, 0));
   else
     draw_cfg_nodes_no_loops (pp, fun);
@@ -267,7 +268,7 @@ draw_cfg_edges (pretty_printer *pp, struct function *fun)
   edge e;
   edge_iterator ei;
   unsigned int idx = 0;
-  FOR_EACH_BB_FN (bb, cfun)
+  FOR_EACH_BB_FN (bb, fun)
     FOR_EACH_EDGE (e, ei, bb->succs)
       {
 	if (e->flags & EDGE_DFS_BACK)
@@ -275,13 +276,13 @@ draw_cfg_edges (pretty_printer *pp, struct function *fun)
 	idx++;
       }
 
-  mark_dfs_back_edges ();
-  FOR_ALL_BB_FN (bb, cfun)
+  mark_dfs_back_edges (fun);
+  FOR_ALL_BB_FN (bb, fun)
     draw_cfg_node_succ_edges (pp, fun->funcdef_no, bb);
 
   /* Restore EDGE_DFS_BACK flag from dfs_back.  */
   idx = 0;
-  FOR_EACH_BB_FN (bb, cfun)
+  FOR_EACH_BB_FN (bb, fun)
     FOR_EACH_EDGE (e, ei, bb->succs)
       {
 	if (bitmap_bit_p (dfs_back, idx))