[gcc r11-3407] Avoid assuming input corresponds to valid source code (PR c/97131).

[Martin Sebor]

https://gcc.gnu.org/g:e92779db3304bc96a6b861f87c5edde8dd4d4030

commit r11-3407-ge92779db3304bc96a6b861f87c5edde8dd4d4030
Author: Martin Sebor <msebor@redhat.com>
Date:   Wed Sep 23 15:02:01 2020 -0600

    Avoid assuming input corresponds to valid source code (PR c/97131).
    
    gcc/c-family/ChangeLog:
    
            PR c/97131
            * c-warn.c (warn_parm_ptrarray_mismatch): Handle more invalid input.
    
    gcc/testsuite/ChangeLog:
    
            PR c/97131
            * gcc.dg/Warray-parameter-6.c: New test.

Diff:
---
 gcc/c-family/c-warn.c                     | 5 +++++
 gcc/testsuite/gcc.dg/Warray-parameter-6.c | 9 +++++++++
 2 files changed, 14 insertions(+)

diff --git a/gcc/c-family/c-warn.c b/gcc/c-family/c-warn.c
index d6db85b6de5..ebd011d1a42 100644
--- a/gcc/c-family/c-warn.c
+++ b/gcc/c-family/c-warn.c
@@ -3181,11 +3181,16 @@ warn_parm_ptrarray_mismatch (location_t origloc, tree curparms, tree newparms)
       while (TREE_CODE (curtyp) == POINTER_TYPE
 	     && TREE_CODE (newtyp) == POINTER_TYPE);
 
+      if (!newtyp)
+	/* Bail on error.  */
+	return;
+
       if (TREE_CODE (curtyp) != ARRAY_TYPE
 	  || TREE_CODE (newtyp) != ARRAY_TYPE)
 	{
 	  if (curtyp == error_mark_node
 	      || newtyp == error_mark_node)
+	    /* Bail on error.  */
 	    return;
 
 	  continue;
diff --git a/gcc/testsuite/gcc.dg/Warray-parameter-6.c b/gcc/testsuite/gcc.dg/Warray-parameter-6.c
new file mode 100644
index 00000000000..609dac96bb6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Warray-parameter-6.c
@@ -0,0 +1,9 @@
+/* PR c/97131 - ICE: Segmentation fault in warn_parm_ptrarray_mismatch
+   { dg-do compile }
+   { dg-options "-Wall" } */
+
+struct bm { };
+
+void ms (struct bm (*at)[1]) { }
+
+void ms (int f1) { }          // { dg-error "conflicting types for 'ms'" }