Re: [PATCH] Move "types deeply equal" code from py-type.c to gdbtypes.c

[Doug Evans <xdje42 at gmail dot com>]

Doug Evans <dje@sebabeach.org> writes:

> WTF?  Where'd the patch go?
> Let's try this again.
>
> On Sat, Nov 9, 2013 at 11:47 AM, Doug Evans <dje@sebabeach.org> wrote:
>> On Thu, Nov 7, 2013 at 8:40 AM, Doug Evans <dje@sebabeach.org> wrote:
>>> On Thu, Nov 7, 2013 at 6:36 AM, Tom Tromey <tromey@redhat.com> wrote:
>>>>>>>>> "Doug" == Doug Evans <dje@sebabeach.org> writes:
>>>>
>>>> Doug> Tom Tromey <tromey@redhat.com> writes:
>>>> Stan> +/* A helper function for tyscm_richcompare that checks two types for
>>>> Stan> +   "deep" equality.  Returns non-zero if the types are considered the
>>>> Stan> +   same, zero otherwise.  */
>>>>>>
>>>> Stan> "tyscm_richcompare"?  Should that be typy_... ?
>>>>>>
>>>>>> It would be helpful if Doug could list all the change he made when
>>>>>> moving the code.
>>>>
>>>> Doug> I don't understand.
>>>> Doug> Which changes?  While useful beyond its present state, this is in
>>>> Doug> essence just a cleanup.
>>>>
>>>> I had thought this patch was more or less a straight move of the code.
>>>> But Stan's note revealed a change from what is currently in the tree.
>>>> So the question is, can you say what else changed?
>>>> That would be handy so I don't have to go over it line-by-line myself.
>>>
>>> Ah.  Except for the comment (*1) the only substantive change is in the result:
>>> Py_{NE,EQ} -> 0.1.
>>>
>>> (*1): Early on I made a copy because I wasn't sure how things would end up,
>>> and left in a FIXME to remind myself to revisit.
>>> I revisited and realized there's no need for the copy, but missed the
>>> comment.  Blech.
>>> "diff -b before after" shows nothing of note to me.
>>
>> Here's v2 of the patch.
>>
>> I fixed the comment and added an assert to check type1,type2 != NULL.
>>
>> I changed the email address in the ChangeLog entry 'cus I'm having
>> problems with this domain.
>> After this email hopefully the switchover is complete.

Well that's weird.
Ok, no more attachment.

2013-11-09  Doug Evans  <xdje42@gmail.com>

	* gdbtypes.c: #include bcache.h, dwarf2loc.h.
	(type_equality_entry): Move here from python/py-type.c.
	(type_equality_entry_d): Ditto.
	(compare_maybe_null_strings, check_types_equal): Ditto.
	(check_types_worklist, types_deeply_equal): Ditto.
	* gdbtypes.h (types_deeply_equal): Declare.
	* python/py-type.c: Remove inclusion of bcache.h, dwarf2loc.h.
	(typy_richcompare): Update.

diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 9069a11..70a7fb5 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -38,6 +38,8 @@
 #include "hashtab.h"
 #include "exceptions.h"
 #include "cp-support.h"
+#include "bcache.h"
+#include "dwarf2loc.h"
 
 /* Initialize BADNESS constants.  */
 
@@ -2494,7 +2496,217 @@ types_equal (struct type *a, struct type *b)
 
   return 0;
 }
+
+/* Deep comparison of types.  */
+
+/* An entry in the type-equality bcache.  */
+
+typedef struct type_equality_entry
+{
+  struct type *type1, *type2;
+} type_equality_entry_d;
+
+DEF_VEC_O (type_equality_entry_d);
+
+/* A helper function to compare two strings.  Returns 1 if they are
+   the same, 0 otherwise.  Handles NULLs properly.  */
+
+static int
+compare_maybe_null_strings (const char *s, const char *t)
+{
+  if (s == NULL && t != NULL)
+    return 0;
+  else if (s != NULL && t == NULL)
+    return 0;
+  else if (s == NULL && t== NULL)
+    return 1;
+  return strcmp (s, t) == 0;
+}
+
+/* A helper function for check_types_worklist that checks two types for
+   "deep" equality.  Returns non-zero if the types are considered the
+   same, zero otherwise.  */
+
+static int
+check_types_equal (struct type *type1, struct type *type2,
+		   VEC (type_equality_entry_d) **worklist)
+{
+  CHECK_TYPEDEF (type1);
+  CHECK_TYPEDEF (type2);
+
+  if (type1 == type2)
+    return 1;
+
+  if (TYPE_CODE (type1) != TYPE_CODE (type2)
+      || TYPE_LENGTH (type1) != TYPE_LENGTH (type2)
+      || TYPE_UNSIGNED (type1) != TYPE_UNSIGNED (type2)
+      || TYPE_NOSIGN (type1) != TYPE_NOSIGN (type2)
+      || TYPE_VARARGS (type1) != TYPE_VARARGS (type2)
+      || TYPE_VECTOR (type1) != TYPE_VECTOR (type2)
+      || TYPE_NOTTEXT (type1) != TYPE_NOTTEXT (type2)
+      || TYPE_INSTANCE_FLAGS (type1) != TYPE_INSTANCE_FLAGS (type2)
+      || TYPE_NFIELDS (type1) != TYPE_NFIELDS (type2))
+    return 0;
+
+  if (!compare_maybe_null_strings (TYPE_TAG_NAME (type1),
+				   TYPE_TAG_NAME (type2)))
+    return 0;
+  if (!compare_maybe_null_strings (TYPE_NAME (type1), TYPE_NAME (type2)))
+    return 0;
+
+  if (TYPE_CODE (type1) == TYPE_CODE_RANGE)
+    {
+      if (memcmp (TYPE_RANGE_DATA (type1), TYPE_RANGE_DATA (type2),
+		  sizeof (*TYPE_RANGE_DATA (type1))) != 0)
+	return 0;
+    }
+  else
+    {
+      int i;
+
+      for (i = 0; i < TYPE_NFIELDS (type1); ++i)
+	{
+	  const struct field *field1 = &TYPE_FIELD (type1, i);
+	  const struct field *field2 = &TYPE_FIELD (type2, i);
+	  struct type_equality_entry entry;
+
+	  if (FIELD_ARTIFICIAL (*field1) != FIELD_ARTIFICIAL (*field2)
+	      || FIELD_BITSIZE (*field1) != FIELD_BITSIZE (*field2)
+	      || FIELD_LOC_KIND (*field1) != FIELD_LOC_KIND (*field2))
+	    return 0;
+	  if (!compare_maybe_null_strings (FIELD_NAME (*field1),
+					   FIELD_NAME (*field2)))
+	    return 0;
+	  switch (FIELD_LOC_KIND (*field1))
+	    {
+	    case FIELD_LOC_KIND_BITPOS:
+	      if (FIELD_BITPOS (*field1) != FIELD_BITPOS (*field2))
+		return 0;
+	      break;
+	    case FIELD_LOC_KIND_ENUMVAL:
+	      if (FIELD_ENUMVAL (*field1) != FIELD_ENUMVAL (*field2))
+		return 0;
+	      break;
+	    case FIELD_LOC_KIND_PHYSADDR:
+	      if (FIELD_STATIC_PHYSADDR (*field1)
+		  != FIELD_STATIC_PHYSADDR (*field2))
+		return 0;
+	      break;
+	    case FIELD_LOC_KIND_PHYSNAME:
+	      if (!compare_maybe_null_strings (FIELD_STATIC_PHYSNAME (*field1),
+					       FIELD_STATIC_PHYSNAME (*field2)))
+		return 0;
+	      break;
+	    case FIELD_LOC_KIND_DWARF_BLOCK:
+	      {
+		struct dwarf2_locexpr_baton *block1, *block2;
+
+		block1 = FIELD_DWARF_BLOCK (*field1);
+		block2 = FIELD_DWARF_BLOCK (*field2);
+		if (block1->per_cu != block2->per_cu
+		    || block1->size != block2->size
+		    || memcmp (block1->data, block2->data, block1->size) != 0)
+		  return 0;
+	      }
+	      break;
+	    default:
+	      internal_error (__FILE__, __LINE__, _("Unsupported field kind "
+						    "%d by check_types_equal"),
+			      FIELD_LOC_KIND (*field1));
+	    }
+
+	  entry.type1 = FIELD_TYPE (*field1);
+	  entry.type2 = FIELD_TYPE (*field2);
+	  VEC_safe_push (type_equality_entry_d, *worklist, &entry);
+	}
+    }
+
+  if (TYPE_TARGET_TYPE (type1) != NULL)
+    {
+      struct type_equality_entry entry;
+
+      if (TYPE_TARGET_TYPE (type2) == NULL)
+	return 0;
+
+      entry.type1 = TYPE_TARGET_TYPE (type1);
+      entry.type2 = TYPE_TARGET_TYPE (type2);
+      VEC_safe_push (type_equality_entry_d, *worklist, &entry);
+    }
+  else if (TYPE_TARGET_TYPE (type2) != NULL)
+    return 0;
+
+  return 1;
+}
+
+/* Check types on a worklist for equality.  Returns zero if any pair
+   is not equal, non-zero if they are all considered equal.  */
+
+static int
+check_types_worklist (VEC (type_equality_entry_d) **worklist,
+		      struct bcache *cache)
+{
+  while (!VEC_empty (type_equality_entry_d, *worklist))
+    {
+      struct type_equality_entry entry;
+      int added;
+
+      entry = *VEC_last (type_equality_entry_d, *worklist);
+      VEC_pop (type_equality_entry_d, *worklist);
+
+      /* If the type pair has already been visited, we know it is
+	 ok.  */
+      bcache_full (&entry, sizeof (entry), cache, &added);
+      if (!added)
+	continue;
 
+      if (check_types_equal (entry.type1, entry.type2, worklist) == 0)
+	return 0;
+    }
+
+  return 1;
+}
+
+/* Return non-zero if types TYPE1 and TYPE2 are equal, as determined by a
+   "deep comparison".  Otherwise return zero.  */
+
+int
+types_deeply_equal (struct type *type1, struct type *type2)
+{
+  volatile struct gdb_exception except;
+  int result = 0;
+  struct bcache *cache;
+  VEC (type_equality_entry_d) *worklist = NULL;
+  struct type_equality_entry entry;
+
+  gdb_assert (type1 != NULL && type2 != NULL);
+
+  /* Early exit for the simple case.  */
+  if (type1 == type2)
+    return 1;
+
+  cache = bcache_xmalloc (NULL, NULL);
+
+  entry.type1 = type1;
+  entry.type2 = type2;
+  VEC_safe_push (type_equality_entry_d, worklist, &entry);
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      result = check_types_worklist (&worklist, cache);
+    }
+  /* check_types_worklist calls several nested helper functions,
+     some of which can raise a GDB Exception, so we just check
+     and rethrow here.  If there is a GDB exception, a comparison
+     is not capable (or trusted), so exit.  */
+  bcache_xfree (cache);
+  VEC_free (type_equality_entry_d, worklist);
+  /* Rethrow if there was a problem.  */
+  if (except.reason < 0)
+    throw_exception (except);
+
+  return result;
+}
+
 /* Compare one type (PARM) for compatibility with another (ARG).
  * PARM is intended to be the parameter type of a function; and
  * ARG is the supplied argument's type.  This function tests if
diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index d7fdedf..c7bef5f 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -1664,4 +1664,6 @@ extern struct type *copy_type (const struct type *type);
 
 extern int types_equal (struct type *, struct type *);
 
+extern int types_deeply_equal (struct type *, struct type *);
+
 #endif /* GDBTYPES_H */
diff --git a/gdb/python/py-type.c b/gdb/python/py-type.c
index 337e307..628a764 100644
--- a/gdb/python/py-type.c
+++ b/gdb/python/py-type.c
@@ -28,8 +28,6 @@
 #include "objfiles.h"
 #include "language.h"
 #include "vec.h"
-#include "bcache.h"
-#include "dwarf2loc.h"
 #include "typeprint.h"
 
 typedef struct pyty_type_object
@@ -961,173 +959,6 @@ typy_str (PyObject *self)
   return result;
 }
 
-/* An entry in the type-equality bcache.  */
-
-typedef struct type_equality_entry
-{
-  struct type *type1, *type2;
-} type_equality_entry_d;
-
-DEF_VEC_O (type_equality_entry_d);
-
-/* A helper function to compare two strings.  Returns 1 if they are
-   the same, 0 otherwise.  Handles NULLs properly.  */
-
-static int
-compare_maybe_null_strings (const char *s, const char *t)
-{
-  if (s == NULL && t != NULL)
-    return 0;
-  else if (s != NULL && t == NULL)
-    return 0;
-  else if (s == NULL && t== NULL)
-    return 1;
-  return strcmp (s, t) == 0;
-}
-
-/* A helper function for typy_richcompare that checks two types for
-   "deep" equality.  Returns Py_EQ if the types are considered the
-   same, Py_NE otherwise.  */
-
-static int
-check_types_equal (struct type *type1, struct type *type2,
-		   VEC (type_equality_entry_d) **worklist)
-{
-  CHECK_TYPEDEF (type1);
-  CHECK_TYPEDEF (type2);
-
-  if (type1 == type2)
-    return Py_EQ;
-
-  if (TYPE_CODE (type1) != TYPE_CODE (type2)
-      || TYPE_LENGTH (type1) != TYPE_LENGTH (type2)
-      || TYPE_UNSIGNED (type1) != TYPE_UNSIGNED (type2)
-      || TYPE_NOSIGN (type1) != TYPE_NOSIGN (type2)
-      || TYPE_VARARGS (type1) != TYPE_VARARGS (type2)
-      || TYPE_VECTOR (type1) != TYPE_VECTOR (type2)
-      || TYPE_NOTTEXT (type1) != TYPE_NOTTEXT (type2)
-      || TYPE_INSTANCE_FLAGS (type1) != TYPE_INSTANCE_FLAGS (type2)
-      || TYPE_NFIELDS (type1) != TYPE_NFIELDS (type2))
-    return Py_NE;
-
-  if (!compare_maybe_null_strings (TYPE_TAG_NAME (type1),
-				   TYPE_TAG_NAME (type2)))
-    return Py_NE;
-  if (!compare_maybe_null_strings (TYPE_NAME (type1), TYPE_NAME (type2)))
-    return Py_NE;
-
-  if (TYPE_CODE (type1) == TYPE_CODE_RANGE)
-    {
-      if (memcmp (TYPE_RANGE_DATA (type1), TYPE_RANGE_DATA (type2),
-		  sizeof (*TYPE_RANGE_DATA (type1))) != 0)
-	return Py_NE;
-    }
-  else
-    {
-      int i;
-
-      for (i = 0; i < TYPE_NFIELDS (type1); ++i)
-	{
-	  const struct field *field1 = &TYPE_FIELD (type1, i);
-	  const struct field *field2 = &TYPE_FIELD (type2, i);
-	  struct type_equality_entry entry;
-
-	  if (FIELD_ARTIFICIAL (*field1) != FIELD_ARTIFICIAL (*field2)
-	      || FIELD_BITSIZE (*field1) != FIELD_BITSIZE (*field2)
-	      || FIELD_LOC_KIND (*field1) != FIELD_LOC_KIND (*field2))
-	    return Py_NE;
-	  if (!compare_maybe_null_strings (FIELD_NAME (*field1),
-					   FIELD_NAME (*field2)))
-	    return Py_NE;
-	  switch (FIELD_LOC_KIND (*field1))
-	    {
-	    case FIELD_LOC_KIND_BITPOS:
-	      if (FIELD_BITPOS (*field1) != FIELD_BITPOS (*field2))
-		return Py_NE;
-	      break;
-	    case FIELD_LOC_KIND_ENUMVAL:
-	      if (FIELD_ENUMVAL (*field1) != FIELD_ENUMVAL (*field2))
-		return Py_NE;
-	      break;
-	    case FIELD_LOC_KIND_PHYSADDR:
-	      if (FIELD_STATIC_PHYSADDR (*field1)
-		  != FIELD_STATIC_PHYSADDR (*field2))
-		return Py_NE;
-	      break;
-	    case FIELD_LOC_KIND_PHYSNAME:
-	      if (!compare_maybe_null_strings (FIELD_STATIC_PHYSNAME (*field1),
-					       FIELD_STATIC_PHYSNAME (*field2)))
-		return Py_NE;
-	      break;
-	    case FIELD_LOC_KIND_DWARF_BLOCK:
-	      {
-		struct dwarf2_locexpr_baton *block1, *block2;
-
-		block1 = FIELD_DWARF_BLOCK (*field1);
-		block2 = FIELD_DWARF_BLOCK (*field2);
-		if (block1->per_cu != block2->per_cu
-		    || block1->size != block2->size
-		    || memcmp (block1->data, block2->data, block1->size) != 0)
-		return Py_NE;
-	      }
-	      break;
-	    default:
-	      internal_error (__FILE__, __LINE__, _("Unsupported field kind "
-						    "%d by check_types_equal"),
-			      FIELD_LOC_KIND (*field1));
-	    }
-
-	  entry.type1 = FIELD_TYPE (*field1);
-	  entry.type2 = FIELD_TYPE (*field2);
-	  VEC_safe_push (type_equality_entry_d, *worklist, &entry);
-	}
-    }
-
-  if (TYPE_TARGET_TYPE (type1) != NULL)
-    {
-      struct type_equality_entry entry;
-
-      if (TYPE_TARGET_TYPE (type2) == NULL)
-	return Py_NE;
-
-      entry.type1 = TYPE_TARGET_TYPE (type1);
-      entry.type2 = TYPE_TARGET_TYPE (type2);
-      VEC_safe_push (type_equality_entry_d, *worklist, &entry);
-    }
-  else if (TYPE_TARGET_TYPE (type2) != NULL)
-    return Py_NE;
-
-  return Py_EQ;
-}
-
-/* Check types on a worklist for equality.  Returns Py_NE if any pair
-   is not equal, Py_EQ if they are all considered equal.  */
-
-static int
-check_types_worklist (VEC (type_equality_entry_d) **worklist,
-		      struct bcache *cache)
-{
-  while (!VEC_empty (type_equality_entry_d, *worklist))
-    {
-      struct type_equality_entry entry;
-      int added;
-
-      entry = *VEC_last (type_equality_entry_d, *worklist);
-      VEC_pop (type_equality_entry_d, *worklist);
-
-      /* If the type pair has already been visited, we know it is
-	 ok.  */
-      bcache_full (&entry, sizeof (entry), cache, &added);
-      if (!added)
-	continue;
-
-      if (check_types_equal (entry.type1, entry.type2, worklist) == Py_NE)
-	return Py_NE;
-    }
-
-  return Py_EQ;
-}
-
 /* Implement the richcompare method.  */
 
 static PyObject *
@@ -1150,30 +981,16 @@ typy_richcompare (PyObject *self, PyObject *other, int op)
     result = Py_EQ;
   else
     {
-      struct bcache *cache;
-      VEC (type_equality_entry_d) *worklist = NULL;
-      struct type_equality_entry entry;
-
-      cache = bcache_xmalloc (NULL, NULL);
-
-      entry.type1 = type1;
-      entry.type2 = type2;
-      VEC_safe_push (type_equality_entry_d, worklist, &entry);
-
       TRY_CATCH (except, RETURN_MASK_ALL)
 	{
-	  result = check_types_worklist (&worklist, cache);
+	  result = types_deeply_equal (type1, type2);
 	}
-      /* check_types_worklist calls several nested Python helper
-	 functions, some of which can raise a GDB Exception, so we
-	 just check and convert here.  If there is a GDB exception, a
-	 comparison is not capable (or trusted), so exit.  */
-      bcache_xfree (cache);
-      VEC_free (type_equality_entry_d, worklist);
+      /* If there is a GDB exception, a comparison is not capable
+	 (or trusted), so exit.  */
       GDB_PY_HANDLE_EXCEPTION (except);
     }
 
-  if (op == result)
+  if (op == (result ? Py_EQ : Py_NE))
     Py_RETURN_TRUE;
   Py_RETURN_FALSE;
 }