[committed] analyzer: fix ICE reporting NULL dereference (PR 93647)

Message ID 20200210231611.32044-1-dmalcolm@redhat.com
State New
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Series
  • [committed] analyzer: fix ICE reporting NULL dereference (PR 93647)
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Commit Message

David Malcolm Feb. 10, 2020, 11:16 p.m.
Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu.
Pushed to master as r10-6566-ge953f9588d4a7ea4183d14914f915329cc37941f.

gcc/analyzer/ChangeLog:
	PR analyzer/93647
	* diagnostic-manager.cc
	(diagnostic_manager::prune_for_sm_diagnostic): Bulletproof against
	VAR being constant.
	* region-model.cc (region_model::get_lvalue_1): Provide a better
	error message when encountering an unhandled tree code.

gcc/testsuite/ChangeLog:
	PR analyzer/93647
	* gcc.dg/analyzer/torture/pr93647.c: New test.
---
 gcc/analyzer/diagnostic-manager.cc              |  6 ++++++
 gcc/analyzer/region-model.cc                    |  2 ++
 gcc/testsuite/gcc.dg/analyzer/torture/pr93647.c | 14 ++++++++++++++
 3 files changed, 22 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/analyzer/torture/pr93647.c

-- 
2.21.0

Patch

diff --git a/gcc/analyzer/diagnostic-manager.cc b/gcc/analyzer/diagnostic-manager.cc
index 1a82d5f22ec..580152586f4 100644
--- a/gcc/analyzer/diagnostic-manager.cc
+++ b/gcc/analyzer/diagnostic-manager.cc
@@ -965,6 +965,12 @@  diagnostic_manager::prune_for_sm_diagnostic (checker_path *path,
 					     tree var,
 					     state_machine::state_t state) const
 {
+  /* If we have a constant (such as NULL), assume its state is also
+     constant, so as not to attempt to get its lvalue whilst tracking the
+     origin of the state.  */
+  if (var && CONSTANT_CLASS_P (var))
+    var = NULL_TREE;
+
   int idx = path->num_events () - 1;
   while (idx >= 0 && idx < (signed)path->num_events ())
     {
diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-model.cc
index 0ae7536a032..fd82360cc6e 100644
--- a/gcc/analyzer/region-model.cc
+++ b/gcc/analyzer/region-model.cc
@@ -4641,6 +4641,8 @@  region_model::get_lvalue_1 (path_var pv, region_model_context *ctxt)
   switch (TREE_CODE (expr))
     {
     default:
+      internal_error ("unhandled tree code in region_model::get_lvalue_1: %qs",
+		      get_tree_code_name (TREE_CODE (expr)));
       gcc_unreachable ();
 
     case ARRAY_REF:
diff --git a/gcc/testsuite/gcc.dg/analyzer/torture/pr93647.c b/gcc/testsuite/gcc.dg/analyzer/torture/pr93647.c
new file mode 100644
index 00000000000..fbfe570780b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/analyzer/torture/pr93647.c
@@ -0,0 +1,14 @@ 
+/* { dg-skip-if "" { *-*-* } { "-fno-fat-lto-objects" } { "" } } */
+
+int *tz;
+
+void
+ky (int);
+
+void
+wd (void)
+{
+  tz = 0;
+  ky (*tz); /* { dg-warning "dereference of NULL" } */
+}
+