[PR 87347] Prevent segfaults if TYPE_ARG_TYPES is NULL

[Martin Jambor <mjambor@suse.cz>]

Hi,

the warning for suspicious calls of abs-like functions segfaults if a
user declared their own parameter-less-ish variant of abs like in the
testcase below.  Fixed by looking whether there is any TYPE_ARG_TYPES
before trying to compare the actual argument with it.

Bootstrapped and tested on x86_64-linux and aarch64-linux, the same on
i686-linux is pending.

OK for trunk?

Thanks,

Martin


2018-09-24  Martin Jambor  <mjambor@suse.cz>

	PR c/87347
	c/
	* c-parser.c (warn_for_abs): Bail out if TYPE_ARG_TYPES is NULL.

	testsuite/
	* gcc.dg/pr87347.c: New test.
---
 gcc/c/c-parser.c               | 7 ++++---
 gcc/testsuite/gcc.dg/pr87347.c | 6 ++++++
 2 files changed, 10 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr87347.c

diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index 1766a256633..a96d15fef1d 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -9116,9 +9116,10 @@ warn_for_abs (location_t loc, tree fndecl, tree arg)
      -Wint-conversion warnings.  Most other wrong types hopefully lead to type
      mismatch errors.  TODO: Think about what to do with FIXED_POINT_TYPE_P
      types and possibly other exotic types.  */
-  if (!INTEGRAL_TYPE_P (atype)
-      && !SCALAR_FLOAT_TYPE_P (atype)
-      && TREE_CODE (atype) != COMPLEX_TYPE)
+  if ((!INTEGRAL_TYPE_P (atype)
+       && !SCALAR_FLOAT_TYPE_P (atype)
+       && TREE_CODE (atype) != COMPLEX_TYPE)
+      || !TYPE_ARG_TYPES (TREE_TYPE (fndecl)))
     return;
 
   enum built_in_function fcode = DECL_FUNCTION_CODE (fndecl);
diff --git a/gcc/testsuite/gcc.dg/pr87347.c b/gcc/testsuite/gcc.dg/pr87347.c
new file mode 100644
index 00000000000..d0bdf2a9fec
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr87347.c
@@ -0,0 +1,6 @@
+/* {dg-do compile} */
+/* { dg-options "-Wabsolute-value" } */
+
+int a;
+int abs();
+void b() { abs(a); }
-- 
2.18.0