[compiler-rt] r215485 - [UBSan] Add returns-nonnull sanitizer.

[Alexey Samsonov]

Author: samsonov
Date: Tue Aug 12 19:26:40 2014
New Revision: 215485

URL: http://llvm.org/viewvc/llvm-project?rev=215485&view=rev
Log:
[UBSan] Add returns-nonnull sanitizer.

Summary:
This patch adds a runtime check verifying that functions
annotated with "returns_nonnull" attribute do in fact return nonnull pointers.
It is based on suggestion by Jakub Jelinek:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20140623/223693.html.

Test Plan: regression test suite

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D4849

Added:
    compiler-rt/trunk/test/ubsan/TestCases/Misc/nonnull.cpp
Modified:
    compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc
    compiler-rt/trunk/lib/ubsan/ubsan_handlers.h

Modified: compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc?rev=215485&r1=215484&r2=215485&view=diff
==============================================================================
--- compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc (original)
+++ compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc Tue Aug 12 19:26:40 2014
@@ -308,3 +308,22 @@ void __ubsan::__ubsan_handle_function_ty
     FunctionTypeMismatchData *Data, ValueHandle Function) {
   handleFunctionTypeMismatch(Data, Function, true);
 }
+
+static void handleNonnullReturn(NonNullReturnData *Data, bool Abort) {
+  SourceLocation Loc = Data->Loc.acquire();
+  if (Loc.isDisabled())
+    return;
+
+  ScopedReport R(Abort);
+
+  Diag(Loc, DL_Error, "null pointer returned from function declared to never "
+                      "return null");
+}
+
+void __ubsan::__ubsan_handle_nonnull_return(NonNullReturnData *Data) {
+  handleNonnullReturn(Data, false);
+}
+
+void __ubsan::__ubsan_handle_nonnull_return_abort(NonNullReturnData *Data) {
+  handleNonnullReturn(Data, true);
+}

Modified: compiler-rt/trunk/lib/ubsan/ubsan_handlers.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/ubsan/ubsan_handlers.h?rev=215485&r1=215484&r2=215485&view=diff
==============================================================================
--- compiler-rt/trunk/lib/ubsan/ubsan_handlers.h (original)
+++ compiler-rt/trunk/lib/ubsan/ubsan_handlers.h Tue Aug 12 19:26:40 2014
@@ -121,6 +121,13 @@ RECOVERABLE(function_type_mismatch,
             FunctionTypeMismatchData *Data,
             ValueHandle Val)
 
+struct NonNullReturnData {
+  SourceLocation Loc;
+};
+
+/// \brief Handle returning null from function with returns_nonnull attribute.
+RECOVERABLE(nonnull_return, NonNullReturnData *Data)
+
 }
 
 #endif // UBSAN_HANDLERS_H

Added: compiler-rt/trunk/test/ubsan/TestCases/Misc/nonnull.cpp
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/ubsan/TestCases/Misc/nonnull.cpp?rev=215485&view=auto
==============================================================================
--- compiler-rt/trunk/test/ubsan/TestCases/Misc/nonnull.cpp (added)
+++ compiler-rt/trunk/test/ubsan/TestCases/Misc/nonnull.cpp Tue Aug 12 19:26:40 2014
@@ -0,0 +1,13 @@
+// RUN: %clangxx -fsanitize=returns-nonnull-attribute %s -O3 -o %t
+// RUN: %run %t foo
+// RUN: %run %t 2>&1 | FileCheck %s
+
+__attribute__((returns_nonnull))
+char *foo(char *a) {
+  return a;
+  // CHECK: nonnull.cpp:[[@LINE+1]]:1: runtime error: null pointer returned from function declared to never return null
+}
+
+int main(int argc, char **argv) {
+  return foo(argv[1]) == 0;
+}