[committed] analyzer: fix ICE on escaped unknown pointers [PR96611]

David Malcolm dmalcolm@redhat.com
Fri Aug 14 20:59:33 GMT 2020


PR analyzer/96611 reports an ICE within the handling for unknown
functions, when passing a pointer to something accessed via a
global pointer, after an unknown function has already been called.

The first unknown function leads to the store being flagged, so
the access to the global pointer leads to (*unknown_svalue) for
the base region of the argument to the 2nd function, and thus
*unknown_svalue being reachable by the 2nd unknown function,
triggering an assertion failure.

Handle this case by rejecting attempts to get a cluster for
the unknown pointer, fixing the ICE.

Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu.
Pushed to master as r11-2707-gee88b536069db8f870c444c441182a9c76ec5bba.

gcc/analyzer/ChangeLog:
	PR analyzer/96611
	* store.cc (store::mark_as_escaped): Reject attempts to
	get a cluster for an unknown pointer.

gcc/testsuite/ChangeLog:
	PR analyzer/96611
	* gcc.dg/analyzer/pr96611.c: New test.
---
 gcc/analyzer/store.cc                   |  3 +++
 gcc/testsuite/gcc.dg/analyzer/pr96611.c | 14 ++++++++++++++
 2 files changed, 17 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/analyzer/pr96611.c

diff --git a/gcc/analyzer/store.cc b/gcc/analyzer/store.cc
index 5fef27c8bd2..950a7784542 100644
--- a/gcc/analyzer/store.cc
+++ b/gcc/analyzer/store.cc
@@ -1691,6 +1691,9 @@ store::mark_as_escaped (const region *base_reg)
   gcc_assert (base_reg);
   gcc_assert (base_reg->get_base_region () == base_reg);
 
+  if (base_reg->symbolic_for_unknown_ptr_p ())
+    return;
+
   binding_cluster *cluster = get_or_create_cluster (base_reg);
   cluster->mark_as_escaped ();
 }
diff --git a/gcc/testsuite/gcc.dg/analyzer/pr96611.c b/gcc/testsuite/gcc.dg/analyzer/pr96611.c
new file mode 100644
index 00000000000..4f7502361cb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/analyzer/pr96611.c
@@ -0,0 +1,14 @@
+struct s { int a; } *ptr;
+void unknown_int_ptr (int *);
+void unknown_void (void);
+
+void test_1 ()
+{
+  unknown_int_ptr (&ptr->a);
+}
+
+void test_2 ()
+{
+  unknown_void ();
+  unknown_int_ptr (&ptr->a);
+}
-- 
2.26.2



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