[UBSan] Implement runtime suppressions (PR25066).

Summary:
Add the ability to suppress UBSan reports for files/functions/modules
at runtime. The user can now pass UBSAN_OPTIONS=suppressions=supp.txt
with the contents of the form:

signed-integer-overflow:file-with-known-overflow.cpp
alignment:function_doing_unaligned_access
vptr:shared_object_with_vptr_failures.so

Suppression categories match the arguments passed to -fsanitize=
flag (although, see below). There is no overhead if suppressions are
not provided. Otherwise there is extra overhead for symbolization.

Limitations:
1) sometimes suppressions need debug info / symbol table to function
   properly (although sometimes frontend generates enough info to
   do the match).
2) it's only possible to suppress recoverable UB kinds - if you've
   built the code with -fno-sanitize-recover=undefined, suppressions
   will not work.
3) categories are fine-grained check kinds, not groups like "undefined"
   or "integer", so you can't write "undefined:file_with_ub.cc".

Reviewers: rsmith, kcc

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D15363

llvm-svn: 256018

1 files changed, 33 insertions, 0 deletions

diff --git a/compiler-rt/test/ubsan/TestCases/Integer/suppressions.cpp b/compiler-rt/test/ubsan/TestCases/Integer/suppressions.cpp
new file mode 100644
index 00000000000..ce3a5469c12
--- /dev/null
+++ b/compiler-rt/test/ubsan/TestCases/Integer/suppressions.cpp
@@ -0,0 +1,33 @@
+// RUN: %clangxx -fsanitize=integer -g0 %s -o %t
+
+// Fails without any suppression.
+// RUN: %env_ubsan_opts=halt_on_error=1 not %run %t 2>&1 | FileCheck %s
+
+// RUN: echo "signed-integer-overflow:%t" > %t.wrong-supp
+// RUN: %env_ubsan_opts=halt_on_error=1:suppressions="%t.wrong-supp" not %run %t 2>&1 | FileCheck %s
+
+// RUN: echo "unsigned-integer-overflow:do_overflow" > %t.func-supp
+// RUN: %env_ubsan_opts=halt_on_error=1:suppressions="%t.func-supp" %run %t
+// RUN: echo "unsigned-integer-overflow:%t" > %t.module-supp
+// RUN: %env_ubsan_opts=halt_on_error=1:suppressions="%t.module-supp" %run %t
+
+// Note: file-level suppressions should work even without debug info.
+// RUN: echo "unsigned-integer-overflow:%s" > %t.file-supp
+// RUN: %env_ubsan_opts=halt_on_error=1:suppressions="%t.file-supp" %run %t
+
+// Suppressions don't work for unrecoverable kinds.
+// RUN: %clangxx -fsanitize=integer -fno-sanitize-recover=integer %s -o %t-norecover
+// RUN: %env_ubsan_opts=halt_on_error=1:suppressions="%t.module-supp" not %run %t-norecover 2>&1 | FileCheck %s
+
+#include <stdint.h>
+
+extern "C" void do_overflow() {
+  (void)(uint64_t(10000000000000000000ull) + uint64_t(9000000000000000000ull));
+  // CHECK: runtime error: unsigned integer overflow
+}
+
+int main() {
+  do_overflow();
+  return 0;
+}
+