Fwd: [patch] implement generic debug() for vectors and hash sets

[Aldy Hernandez <aldyh at redhat dot com>]

PING*3

---------- Forwarded message ----------
From: Aldy Hernandez <aldyh@redhat.com>
Date: Mon, Oct 16, 2017 at 9:52 AM
Subject: [patch] implement generic debug() for vectors and hash sets
To: gcc-patches <gcc-patches@gcc.gnu.org>


We have a generic mechanism for dumping types from the debugger with:

(gdb) call debug(some_type)

However, even though most types are implemented, we have no canonical
way of dumping vectors or hash sets.

The attached patch fixes this oversight.  With it you can call
debug(vec<>) and debug(hash_set<>) with the following types: rtx,
tree, basic_block, edge, rtx_insn.  More can be added simply by adding
a debug_slim(your_type) overload and calling:

  DEFINE_DEBUG_VEC (your_type)
  DEFINE_DEBUG_HASH_SET (your_type)

Here is an example of how things look with this patch:

vec of edges:
[0] = <edge 0x0x7f3f81c0d700 (6 -> 10)>

vec of bbs:
[0] = <basic_block 0x7f3f81ac9410 (6)>
[1] = <basic_block 0x7f3f81ac96e8 (10)>

vec of trees:
[0] =  <integer_type 0x7f3f81ad55e8 int>
[1] =  <integer_type 0x7f3f81ad5498 short int>
[2] =  <integer_cst 0x7f3f81ada078 0>

vec of rtx:
[0] = (reg:SI 87)
[1] = (reg:SI 87)

hash of bbs:
<basic_block 0x7f3f81ac96e8 (10)>
<basic_block 0x7f3f81ac9410 (6)>

OK for mainline?

gcc/

	* vec.h (debug_helper): New function.
	(DEFINE_DEBUG_VEC): New macro.
	* hash-set.h (debug_helper): New function.
	(DEFINE_DEBUG_HASH_SET): New macro.
	* cfg.c (debug_slim (edge)): New function.
	Call DEFINE_DEBUG_VEC for edges.
	Call DEFINE_DEBUG_HASH_SET for edges.
	* cfghooks.c (debug_slim (basic_block)): New function.
	Call DEFINE_DEBUG_VEC for basic blocks.
	Call DEFINE_DEBUG_HASH_SET for basic blocks.
	* print-tree.c (debug_slim): New function to handle trees.
	Call DEFINE_DEBUG_VEC for trees.
	Call DEFINE_DEBUG_HASH_SET for trees.
	(debug (vec<tree, va_gc>) &): Remove.
	(debug (<vec<tree, va_gc>) *): Remove.
	* print-rtl.c (debug_slim): New function to handle const_rtx.
	Call DEFINE_DEBUG_VEC for rtx_def.
	Call DEFINE_DEBUG_VEC for rtx_insn.
	Call DEFINE_DEBUG_HASH_SET for rtx_def.
	Call DEFINE_DEBUG_HASH_SET for rtx_insn.
	* sel-sched-dump.c (debug (vec<rtx_insn *> &): Remove.
	(debug (vec<rtx_insn *> *ptr): Remove.
	(debug_insn_vector): Remove.
	* stor-layout.c (debug_rli): Call debug() instead of debug_vec_tree.

diff --git a/gcc/cfg.c b/gcc/cfg.c
index 01e68aeda51..4d02fb56cbf 100644
--- a/gcc/cfg.c
+++ b/gcc/cfg.c
@@ -573,6 +573,16 @@ debug (edge_def *ptr)
   else
     fprintf (stderr, "<nil>\n");
 }
+
+static void
+debug_slim (edge e)
+{
+  fprintf (stderr, "<edge 0x%p (%d -> %d)>", (void *) e,
+	   e->src->index, e->dest->index);
+}
+
+DEFINE_DEBUG_VEC (edge)
+DEFINE_DEBUG_HASH_SET (edge)
 
 /* Simple routines to easily allocate AUX fields of basic blocks.  */
 
diff --git a/gcc/cfghooks.c b/gcc/cfghooks.c
index 258a5eabf8d..73b196feec7 100644
--- a/gcc/cfghooks.c
+++ b/gcc/cfghooks.c
@@ -304,6 +304,14 @@ debug (basic_block_def *ptr)
     fprintf (stderr, "<nil>\n");
 }
 
+static void
+debug_slim (basic_block ptr)
+{
+  fprintf (stderr, "<basic_block %p (%d)>", (void *) ptr, ptr->index);
+}
+
+DEFINE_DEBUG_VEC (basic_block_def *)
+DEFINE_DEBUG_HASH_SET (basic_block_def *)
 
 /* Dumps basic block BB to pretty-printer PP, for use as a label of
    a DOT graph record-node.  The implementation of this hook is
diff --git a/gcc/hash-set.h b/gcc/hash-set.h
index d2247d39571..58f7750243a 100644
--- a/gcc/hash-set.h
+++ b/gcc/hash-set.h
@@ -123,6 +123,44 @@ private:
   hash_table<Traits> m_table;
 };
 
+/* Generic hash_set<TYPE> debug helper.
+
+   This needs to be instantiated for each hash_set<TYPE> used throughout
+   the compiler like this:
+
+    DEFINE_DEBUG_HASH_SET (TYPE)
+
+   The reason we have a debug_helper() is because GDB can't
+   disambiguate a plain call to debug(some_hash), and it must be called
+   like debug<TYPE>(some_hash).  */
+template<typename T>
+void
+debug_helper (hash_set<T> &ref)
+{
+  for (typename hash_set<T>::iterator it = ref.begin ();
+       it != ref.end (); ++it)
+    {
+      debug_slim (*it);
+      fputc ('\n', stderr);
+    }
+}
+
+#define DEFINE_DEBUG_HASH_SET(T) \
+  template static void debug_helper (hash_set<T> &);	\
+  DEBUG_FUNCTION void					\
+  debug (hash_set<T> &ref)				\
+  {							\
+    debug_helper <T> (ref);				\
+  }							\
+  DEBUG_FUNCTION void					\
+  debug (hash_set<T> *ptr)				\
+  {							\
+    if (ptr)						\
+      debug (*ptr);					\
+    else						\
+      fprintf (stderr, "<nil>\n");			\
+  }
+
 /* ggc marking routines.  */
 
 template<typename K, typename H>
diff --git a/gcc/print-rtl.c b/gcc/print-rtl.c
index 28d99862cad..5fe23801ab2 100644
--- a/gcc/print-rtl.c
+++ b/gcc/print-rtl.c
@@ -967,6 +967,23 @@ debug (const rtx_def *ptr)
     fprintf (stderr, "<nil>\n");
 }
 
+/* Like debug_rtx but with no newline, as debug_helper will add one.
+
+   Note: No debug_slim(rtx_insn *) variant implemented, as this
+   function can serve for both rtx and rtx_insn.  */
+
+static void
+debug_slim (const_rtx x)
+{
+  rtx_writer w (stderr, 0, false, false, NULL);
+  w.print_rtx (x);
+}
+
+DEFINE_DEBUG_VEC (rtx_def *)
+DEFINE_DEBUG_VEC (rtx_insn *)
+DEFINE_DEBUG_HASH_SET (rtx_def *)
+DEFINE_DEBUG_HASH_SET (rtx_insn *)
+
 /* Count of rtx's to print with debug_rtx_list.
    This global exists because gdb user defined commands have no arguments.  */
 
diff --git a/gcc/print-tree.c b/gcc/print-tree.c
index d534c76ee49..3a0f85d4038 100644
--- a/gcc/print-tree.c
+++ b/gcc/print-tree.c
@@ -1095,32 +1095,6 @@ debug_raw (vec<tree, va_gc> &ref)
 }
 
 DEBUG_FUNCTION void
-debug (vec<tree, va_gc> &ref)
-{
-  tree elt;
-  unsigned ix;
-
-  /* Print the slot this node is in, and its code, and address.  */
-  fprintf (stderr, "<VEC");
-  dump_addr (stderr, " ", ref.address ());
-
-  FOR_EACH_VEC_ELT (ref, ix, elt)
-    {
-      fprintf (stderr, "elt:%d ", ix);
-      debug (elt);
-    }
-}
-
-DEBUG_FUNCTION void
-debug (vec<tree, va_gc> *ptr)
-{
-  if (ptr)
-    debug (*ptr);
-  else
-    fprintf (stderr, "<nil>\n");
-}
-
-DEBUG_FUNCTION void
 debug_raw (vec<tree, va_gc> *ptr)
 {
   if (ptr)
@@ -1129,8 +1103,11 @@ debug_raw (vec<tree, va_gc> *ptr)
     fprintf (stderr, "<nil>\n");
 }
 
-DEBUG_FUNCTION void
-debug_vec_tree (vec<tree, va_gc> *vec)
+static void
+debug_slim (tree t)
 {
-  debug_raw (vec);
+  print_node_brief (stderr, "", t, 0);
 }
+
+DEFINE_DEBUG_VEC (tree)
+DEFINE_DEBUG_HASH_SET (tree)
diff --git a/gcc/sel-sched-dump.c b/gcc/sel-sched-dump.c
index 388a8af54c6..027b6b1c7c6 100644
--- a/gcc/sel-sched-dump.c
+++ b/gcc/sel-sched-dump.c
@@ -989,35 +989,6 @@ debug_blist (blist_t bnds)
   restore_dump ();
 }
 
-/* Dump a rtx vector REF.  */
-DEBUG_FUNCTION void
-debug (vec<rtx_insn *> &ref)
-{
-  switch_dump (stderr);
-  dump_insn_vector (ref);
-  sel_print ("\n");
-  restore_dump ();
-}
-
-DEBUG_FUNCTION void
-debug (vec<rtx_insn *> *ptr)
-{
-  if (ptr)
-    debug (*ptr);
-  else
-    fprintf (stderr, "<nil>\n");
-}
-
-/* Dump an insn vector SUCCS.  */
-DEBUG_FUNCTION void
-debug_insn_vector (rtx_vec_t succs)
-{
-  switch_dump (stderr);
-  dump_insn_vector (succs);
-  sel_print ("\n");
-  restore_dump ();
-}
-
 /* Dump a hard reg set SET to stderr.  */
 DEBUG_FUNCTION void
 debug_hard_reg_set (HARD_REG_SET set)
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 02739b0ed7f..9577cfa47ef 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -941,7 +941,7 @@ debug_rli (record_layout_info rli)
   if (!vec_safe_is_empty (rli->pending_statics))
     {
       fprintf (stderr, "pending statics:\n");
-      debug_vec_tree (rli->pending_statics);
+      debug (rli->pending_statics);
     }
 }
 
diff --git a/gcc/vec.h b/gcc/vec.h
index cbdd439571b..b145eef2bc7 100644
--- a/gcc/vec.h
+++ b/gcc/vec.h
@@ -407,6 +407,83 @@ struct GTY((user)) vec
 {
 };
 
+/* Generic vec<> debug helpers.
+
+   These need to be instantiated for each vec<TYPE> used throughout
+   the compiler like this:
+
+    DEFINE_DEBUG_VEC (TYPE)
+
+   The reason we have a debug_helper() is because GDB can't
+   disambiguate a plain call to debug(some_vec), and it must be called
+   like debug<TYPE>(some_vec).  */
+
+template<typename T>
+void
+debug_helper (vec<T> &ref)
+{
+  unsigned i;
+  for (i = 0; i < ref.length (); ++i)
+    {
+      fprintf (stderr, "[%d] = ", i);
+      debug_slim (ref[i]);
+      fputc ('\n', stderr);
+    }
+}
+
+/* We need a separate va_gc variant here because default template
+   argument for functions cannot be used in c++-98.  Once this
+   restriction is removed, those variant should be folded with the
+   above debug_helper.  */
+
+template<typename T>
+void
+debug_helper (vec<T, va_gc> &ref)
+{
+  unsigned i;
+  for (i = 0; i < ref.length (); ++i)
+    {
+      fprintf (stderr, "[%d] = ", i);
+      debug_slim (ref[i]);
+      fputc ('\n', stderr);
+    }
+}
+
+/* Macro to define debug(vec<T>) and debug(vec<T, va_gc>) helper
+   functions for a type T.  */
+
+#define DEFINE_DEBUG_VEC(T) \
+  template static void debug_helper (vec<T> &);		\
+  template static void debug_helper (vec<T, va_gc> &);	\
+  /* Define the vec<T> debug functions.  */		\
+  DEBUG_FUNCTION void					\
+  debug (vec<T> &ref)					\
+  {							\
+    debug_helper <T> (ref);				\
+  }							\
+  DEBUG_FUNCTION void					\
+  debug (vec<T> *ptr)					\
+  {							\
+    if (ptr)						\
+      debug (*ptr);					\
+    else						\
+      fprintf (stderr, "<nil>\n");			\
+  }							\
+  /* Define the vec<T, va_gc> debug functions.  */	\
+  DEBUG_FUNCTION void					\
+  debug (vec<T, va_gc> &ref)				\
+  {							\
+    debug_helper <T> (ref);				\
+  }							\
+  DEBUG_FUNCTION void					\
+  debug (vec<T, va_gc> *ptr)				\
+  {							\
+    if (ptr)						\
+      debug (*ptr);					\
+    else						\
+      fprintf (stderr, "<nil>\n");			\
+  }
+
 /* Default-construct N elements in DST.  */
 
 template <typename T>