Fix setting of DECL_CONTEXT in pushdecl (PR c/93072)

[Joseph Myers <joseph at codesourcery dot com>]

Bug 93072 is a case where the C front end (a) wrongly interprets an
inline declaration at block scope as indicating that DECL_CONTEXT
should be set for an inline function and (b) this results in an ICE.
This is a regression resulting from a previous fix of mine for other
bugs involving such declarations being wrongly interpreted elsewhere
as nested function declarations.  The fix is similar to the previous
fix: use TREE_PUBLIC instead of DECL_EXTERNAL in another place as the
relevant test to determine whether to set DECL_CONTEXT.  (When a
variable reaches the code in question in pushdecl, the two are
equivalent.)

Bootstrapped with no regressions for x86_64-pc-linux-gnu.  Applied to 
mainline.  Will backport to GCC 9 and 8 branches.

gcc/c:
2020-01-15  Joseph Myers  <joseph@codesourcery.com>

	PR c/93072
	* c-decl.c (pushdecl): Use TREE_PUBLIC, not DECL_EXTERNAL, to
	determine whether to set DECL_CONTEXT.

gcc/testsuite:
2020-01-15  Joseph Myers  <joseph@codesourcery.com>

	PR c/93072
	* gcc.dg/inline-42.c, gcc.dg/inline-43.c: New tests.

diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index fa834d91730..8281af7307a 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -3048,7 +3048,7 @@ pushdecl (tree x)
      unless they have initializers (which generate code).  */
   if (current_function_decl
       && (!VAR_OR_FUNCTION_DECL_P (x)
-	  || DECL_INITIAL (x) || !DECL_EXTERNAL (x)))
+	  || DECL_INITIAL (x) || !TREE_PUBLIC (x)))
     DECL_CONTEXT (x) = current_function_decl;
 
   /* Anonymous decls are just inserted in the scope.  */
diff --git a/gcc/testsuite/gcc.dg/inline-42.c b/gcc/testsuite/gcc.dg/inline-42.c
new file mode 100644
index 00000000000..f5ccea8f3cf
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/inline-42.c
@@ -0,0 +1,50 @@
+/* Test inline functions declared in inner scopes.  Bug 93072.  */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+void
+inline_1 (void)
+{
+}
+
+void
+inline_2 (void)
+{
+}
+
+static void
+inline_static_1 (void)
+{
+}
+
+static void
+inline_static_2 (void)
+{
+}
+
+static void
+test (void)
+{
+  inline void inline_1 (void);
+  if (inline_1 == 0) ;
+  extern inline void inline_2 (void);
+  if (inline_2 == 0) ;
+  inline void inline_3 (void);
+  if (inline_3 == 0) ;
+  extern inline void inline_4 (void);
+  if (inline_4 == 0) ;
+  inline void inline_static_1 (void);
+  if (inline_static_1 == 0) ;
+  extern inline void inline_static_2 (void);
+  if (inline_static_2 == 0) ;
+}
+
+void
+inline_3 (void)
+{
+}
+
+void
+inline_4 (void)
+{
+}
diff --git a/gcc/testsuite/gcc.dg/inline-43.c b/gcc/testsuite/gcc.dg/inline-43.c
new file mode 100644
index 00000000000..87b24450384
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/inline-43.c
@@ -0,0 +1,50 @@
+/* Test inline functions declared in inner scopes.  Bug 93072.  */
+/* { dg-do compile } */
+/* { dg-options "-fgnu89-inline" } */
+
+void
+inline_1 (void)
+{
+}
+
+void
+inline_2 (void)
+{
+}
+
+static void
+inline_static_1 (void)
+{
+}
+
+static void
+inline_static_2 (void)
+{
+}
+
+static void
+test (void)
+{
+  inline void inline_1 (void);
+  if (inline_1 == 0) ;
+  extern inline void inline_2 (void);
+  if (inline_2 == 0) ;
+  inline void inline_3 (void);
+  if (inline_3 == 0) ;
+  extern inline void inline_4 (void);
+  if (inline_4 == 0) ;
+  inline void inline_static_1 (void);
+  if (inline_static_1 == 0) ;
+  extern inline void inline_static_2 (void);
+  if (inline_static_2 == 0) ;
+}
+
+void
+inline_3 (void)
+{
+}
+
+void
+inline_4 (void)
+{
+}

-- 
Joseph S. Myers
joseph@codesourcery.com