[PATCH] tree-optimization/116481 - avoid building function_type[]

[Richard Biener]

The following avoids building an array type with function or method
element type during diagnosing an array bound violation as this
will result in an error, rejecting a program with a not too useful
error message.  Instead build such array type manually.

Bootstrapped and tested on x86_64-unknown-linux-gnu, OK?

Thanks,
Richard.

        PR tree-optimization/116481
        * pointer-query.cc (build_printable_array_type):
        Build an array types with function or method element type
        manually to avoid bogus diagnostic.

        * gcc.dg/pr116481.c: New testcase.
---
 gcc/pointer-query.cc            | 11 +++++++++++
 gcc/testsuite/gcc.dg/pr116481.c | 13 +++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/pr116481.c

diff --git a/gcc/pointer-query.cc b/gcc/pointer-query.cc
index c8ab0571e57..a85c04128ff 100644
--- a/gcc/pointer-query.cc
+++ b/gcc/pointer-query.cc
@@ -2587,6 +2587,17 @@ array_elt_at_offset (tree artype, HOST_WIDE_INT off,
 tree
 build_printable_array_type (tree eltype, unsigned HOST_WIDE_INT nelts)
 {
+  /* Cannot build an array type of functions or methods without
+     an error diagnostic.  */
+  if (FUNC_OR_METHOD_TYPE_P (eltype))
+    {
+      tree arrtype = make_node (ARRAY_TYPE);
+      TREE_TYPE (arrtype) = eltype;
+      TYPE_SIZE (arrtype) = bitsize_zero_node;
+      TYPE_SIZE_UNIT (arrtype) = size_zero_node;
+      return arrtype;
+    }
+
   if (TYPE_SIZE_UNIT (eltype)
       && TREE_CODE (TYPE_SIZE_UNIT (eltype)) == INTEGER_CST
       && !integer_zerop (TYPE_SIZE_UNIT (eltype))
diff --git a/gcc/testsuite/gcc.dg/pr116481.c b/gcc/testsuite/gcc.dg/pr116481.c
new file mode 100644
index 00000000000..3ee6d747087
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr116481.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Warray-bounds" } */
+
+extern void tramp ();
+
+int is_trampoline (void* function) /* { dg-bogus "arrays of functions are not 
meaningful" } */
+{
+  void* tramp_address = tramp;
+  if (!(((unsigned long)function & 3) == 2))
+    return 0;
+  return (((long *) ((char*)function - 2))[0]
+         == ((long *) ((char*)tramp_address-2))[0]); /* { dg-warning "outside 
array bounds" } */
+}
-- 
2.43.0