[ubsan] PR33081: Skip the standard type checks for volatile

Skip checks for null dereference, alignment violation, object size
violation, and dynamic type violation if the pointer points to volatile
data.

Differential Revision: https://reviews.llvm.org/D34262

llvm-svn: 305546

2 files changed, 12 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 15829888ead..7359006677f 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -549,6 +549,11 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
   if (Ptr->getType()->getPointerAddressSpace())
     return;
 
+  // Don't check pointers to volatile data. The behavior here is implementation-
+  // defined.
+  if (Ty.isVolatileQualified())
+    return;
+
   SanitizerScope SanScope(this);
 
   SmallVector<std::pair<llvm::Value *, SanitizerMask>, 3> Checks;
diff --git a/clang/test/CodeGen/ubsan-volatile.c b/clang/test/CodeGen/ubsan-volatile.c
new file mode 100644
index 00000000000..ce54aada81f
--- /dev/null
+++ b/clang/test/CodeGen/ubsan-volatile.c
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -fsanitize=null,alignment,object-size,vptr -S -emit-llvm %s -o - | FileCheck %s
+
+// CHECK: @volatile_null_deref
+void volatile_null_deref(volatile int *p) {
+  // CHECK-NOT: call{{.*}}ubsan
+  *p;
+}