c: Handle C_TYPE_INCOMPLETE_VARS even for ENUMERAL_TYPEs [PR94172]

The following testcases ICE, because they contain extern variable
declarations with incomplete enum types that is later completed and after
that those variables are accessed.  The ICEs are because the vars then may have
incorrect DECL_MODE etc., e.g. in the first case the var has SImode
DECL_MODE (the guessed mode for the enum), but the enum then actually has
DImode because its enumerators don't fit into unsigned int.

The following patch fixes it by using C_TYPE_INCOMPLETE_VARS not just on
incomplete struct/union types, but also incomplete enum types.
TYPE_VFIELD can't be used as it is TYPE_MIN_VALUE on ENUMERAL_TYPE,
thankfully TYPE_LANG_SLOT_1 has been used in the C FE only on
FUNCTION_TYPEs.

2020-03-17  Jakub Jelinek  <jakub@redhat.com>

	PR c/94172
	* c-tree.h (C_TYPE_INCOMPLETE_VARS): Define to TYPE_LANG_SLOT_1
	instead of TYPE_VFIELD, and support it on {RECORD,UNION,ENUMERAL}_TYPE.
	(TYPE_ACTUAL_ARG_TYPES): Check that it is only used on FUNCTION_TYPEs.
	* c-decl.c (pushdecl): Push C_TYPE_INCOMPLETE_VARS also to
	ENUMERAL_TYPEs.
	(finish_incomplete_vars): New function, moved from finish_struct.  Use
	relayout_decl instead of layout_decl.
	(finish_struct): Remove obsolete comment about C_TYPE_INCOMPLETE_VARS
	being TYPE_VFIELD.  Use finish_incomplete_vars.
	(finish_enum): Clear C_TYPE_INCOMPLETE_VARS.  Call
	finish_incomplete_vars.
	* c-typeck.c (c_build_qualified_type): Clear C_TYPE_INCOMPLETE_VARS
	also on ENUMERAL_TYPEs.

	* gcc.dg/pr94172-1.c: New test.
	* gcc.dg/pr94172-2.c: New test.

diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index c38f1d736058bd12977288acd930ebb690ab5b17..1c3ca1b47096f213b2446187636e4f9eb2781c21 100644 (file)
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,23 @@
+2020-04-07  Jakub Jelinek  <jakub@redhat.com>
+
+       Backported from mainline
+       2020-03-17  Jakub Jelinek  <jakub@redhat.com>
+
+       PR c/94172
+       * c-tree.h (C_TYPE_INCOMPLETE_VARS): Define to TYPE_LANG_SLOT_1
+       instead of TYPE_VFIELD, and support it on {RECORD,UNION,ENUMERAL}_TYPE.
+       (TYPE_ACTUAL_ARG_TYPES): Check that it is only used on FUNCTION_TYPEs.
+       * c-decl.c (pushdecl): Push C_TYPE_INCOMPLETE_VARS also to
+       ENUMERAL_TYPEs.
+       (finish_incomplete_vars): New function, moved from finish_struct.  Use
+       relayout_decl instead of layout_decl.
+       (finish_struct): Remove obsolete comment about C_TYPE_INCOMPLETE_VARS
+       being TYPE_VFIELD.  Use finish_incomplete_vars.
+       (finish_enum): Clear C_TYPE_INCOMPLETE_VARS.  Call
+       finish_incomplete_vars.
+       * c-typeck.c (c_build_qualified_type): Clear C_TYPE_INCOMPLETE_VARS
+       also on ENUMERAL_TYPEs.
+
 2020-03-12  Release Manager
 
        * GCC 9.3.0 released.

diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 859a624125830f7baf594e6a64790d466ee8068d..350e08e22c2ed6bd88d68500c9c9f427764cf3bd 100644 (file)
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -3272,7 +3272,8 @@ pushdecl (tree x)
        element = TREE_TYPE (element);
       element = TYPE_MAIN_VARIANT (element);
 
-      if (RECORD_OR_UNION_TYPE_P (element)
+      if ((RECORD_OR_UNION_TYPE_P (element)
+          || TREE_CODE (element) == ENUMERAL_TYPE)
          && (TREE_CODE (x) != TYPE_DECL
              || TREE_CODE (TREE_TYPE (x)) == ARRAY_TYPE)
          && !COMPLETE_TYPE_P (element))
@@ -8141,6 +8142,26 @@ field_decl_cmp (const void *x_p, const void *y_p)
   return 1;
 }
 
+/* If this structure or union completes the type of any previous
+   variable declaration, lay it out and output its rtl.  */
+static void
+finish_incomplete_vars (tree incomplete_vars, bool toplevel)
+{
+  for (tree x = incomplete_vars; x; x = TREE_CHAIN (x))
+    {
+      tree decl = TREE_VALUE (x);
+      if (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
+       layout_array_type (TREE_TYPE (decl));
+      if (TREE_CODE (decl) != TYPE_DECL)
+       {
+         relayout_decl (decl);
+         if (c_dialect_objc ())
+           objc_check_decl (decl);
+         rest_of_decl_compilation (decl, toplevel, 0);
+       }
+    }
+}
+
 /* Fill in the fields of a RECORD_TYPE or UNION_TYPE node, T.
    LOC is the location of the RECORD_TYPE or UNION_TYPE's definition.
    FIELDLIST is a chain of FIELD_DECL nodes for the fields.
@@ -8399,13 +8420,6 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes,
       warning_at (loc, 0, "union cannot be made transparent");
     }
 
-  /* Note: C_TYPE_INCOMPLETE_VARS overloads TYPE_VFIELD which is used
-     in dwarf2out via rest_of_decl_compilation below and means
-     something totally different.  Since we will be clearing
-     C_TYPE_INCOMPLETE_VARS shortly after we iterate through them,
-     clear it ahead of time and avoid problems in dwarf2out.  Ideally,
-     C_TYPE_INCOMPLETE_VARS should use some language specific
-     node.  */
   tree incomplete_vars = C_TYPE_INCOMPLETE_VARS (TYPE_MAIN_VARIANT (t));
   for (x = TYPE_MAIN_VARIANT (t); x; x = TYPE_NEXT_VARIANT (x))
     {
@@ -8426,21 +8440,7 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes,
   /* Finish debugging output for this type.  */
   rest_of_type_compilation (t, toplevel);
 
-  /* If this structure or union completes the type of any previous
-     variable declaration, lay it out and output its rtl.  */
-  for (x = incomplete_vars; x; x = TREE_CHAIN (x))
-    {
-      tree decl = TREE_VALUE (x);
-      if (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
-       layout_array_type (TREE_TYPE (decl));
-      if (TREE_CODE (decl) != TYPE_DECL)
-       {
-         layout_decl (decl, 0);
-         if (c_dialect_objc ())
-           objc_check_decl (decl);
-         rest_of_decl_compilation (decl, toplevel, 0);
-       }
-    }
+  finish_incomplete_vars (incomplete_vars, toplevel);
 
   /* If we're inside a function proper, i.e. not file-scope and not still
      parsing parameters, then arrange for the size of a variable sized type
@@ -8719,8 +8719,10 @@ finish_enum (tree enumtype, tree values, tree attributes)
   TYPE_LANG_SPECIFIC (enumtype) = lt;
 
   /* Fix up all variant types of this enum type.  */
+  tree incomplete_vars = C_TYPE_INCOMPLETE_VARS (TYPE_MAIN_VARIANT (enumtype));
   for (tem = TYPE_MAIN_VARIANT (enumtype); tem; tem = TYPE_NEXT_VARIANT (tem))
     {
+      C_TYPE_INCOMPLETE_VARS (tem) = NULL_TREE;
       if (tem == enumtype)
        continue;
       TYPE_VALUES (tem) = TYPE_VALUES (enumtype);
@@ -8739,6 +8741,8 @@ finish_enum (tree enumtype, tree values, tree attributes)
   /* Finish debugging output for this type.  */
   rest_of_type_compilation (enumtype, toplevel);
 
+  finish_incomplete_vars (incomplete_vars, toplevel);
+
   /* If this enum is defined inside a struct, add it to
      struct_types.  */
   if (warn_cxx_compat

diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index 7e35ab1f0bcfe7ece008788547e29261592899f4..147a7e867aae10866621cb6294289845c1eda374 100644 (file)
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -38,9 +38,12 @@ along with GCC; see the file COPYING3.  If not see
    nonzero if the definition of the type has already started.  */
 #define C_TYPE_BEING_DEFINED(TYPE) TYPE_LANG_FLAG_0 (TYPE)
 
-/* In an incomplete RECORD_TYPE or UNION_TYPE, a list of variable
-   declarations whose type would be completed by completing that type.  */
-#define C_TYPE_INCOMPLETE_VARS(TYPE) TYPE_VFIELD (TYPE)
+/* In an incomplete RECORD_TYPE, UNION_TYPE or ENUMERAL_TYPE, a list of
+   variable declarations whose type would be completed by completing
+   that type.  */
+#define C_TYPE_INCOMPLETE_VARS(TYPE) \
+  TYPE_LANG_SLOT_1 (TREE_CHECK4 (TYPE, RECORD_TYPE, UNION_TYPE, \
+                                QUAL_UNION_TYPE, ENUMERAL_TYPE))
 
 /* In an IDENTIFIER_NODE, nonzero if this identifier is actually a
    keyword.  C_RID_CODE (node) is then the RID_* value of the keyword.  */
@@ -111,7 +114,8 @@ along with GCC; see the file COPYING3.  If not see
 /* For FUNCTION_TYPE, a hidden list of types of arguments.  The same as
    TYPE_ARG_TYPES for functions with prototypes, but created for functions
    without prototypes.  */
-#define TYPE_ACTUAL_ARG_TYPES(NODE) TYPE_LANG_SLOT_1 (NODE)
+#define TYPE_ACTUAL_ARG_TYPES(NODE) \
+  TYPE_LANG_SLOT_1 (FUNCTION_TYPE_CHECK (NODE))
 
 /* For a CONSTRUCTOR, whether some initializer contains a
    subexpression meaning it is not a constant expression.  */

diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index c0582a54c93ab3918ba9fd781d062cec55d5dbb0..24106c126cde958b496254f11f1828f654e9ad46 100644 (file)
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -14965,7 +14965,8 @@ c_build_qualified_type (tree type, int type_quals, tree orig_qual_type,
                   : build_qualified_type (type, type_quals));
   /* A variant type does not inherit the list of incomplete vars from the
      type main variant.  */
-  if (RECORD_OR_UNION_TYPE_P (var_type)
+  if ((RECORD_OR_UNION_TYPE_P (var_type)
+       || TREE_CODE (var_type) == ENUMERAL_TYPE)
       && TYPE_MAIN_VARIANT (var_type) != var_type)
     C_TYPE_INCOMPLETE_VARS (var_type) = 0;
   return var_type;

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c10d50b623b997c9665b131565a0bad89a5cdb87..18025a5fa58281a50814af0e7d2fea181499ea1c 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -3,6 +3,10 @@
        Backported from mainline
        2020-03-17  Jakub Jelinek  <jakub@redhat.com>
 
+       PR c/94172
+       * gcc.dg/pr94172-1.c: New test.
+       * gcc.dg/pr94172-2.c: New test.
+
        PR c++/90995
        * g++.dg/cpp0x/enum40.C: New test.
 

diff --git a/gcc/testsuite/gcc.dg/pr94172-1.c b/gcc/testsuite/gcc.dg/pr94172-1.c
new file mode 100644 (file)
index 0000000..12f84af
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr94172-1.c
@@ -0,0 +1,12 @@
+/* PR c/94172 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+extern enum E e;
+enum E { l = 0x100000000ULL };
+
+unsigned long long
+foo (void)
+{
+  return e;
+}

diff --git a/gcc/testsuite/gcc.dg/pr94172-2.c b/gcc/testsuite/gcc.dg/pr94172-2.c
new file mode 100644 (file)
index 0000000..bb7b060
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr94172-2.c
@@ -0,0 +1,19 @@
+/* PR c/94172 */
+/* { dg-do compile } */
+/* { dg-options "-Os -g -fshort-enums" } */
+
+extern enum E e;
+extern void bar (int a);
+enum E { F };
+
+void
+foo (int a)
+{
+  int l = e;
+  if (a)
+    {
+      __asm volatile ("nop");
+      l = 0;
+    }
+  bar (l);
+}