Fix use-after-free bug in Tooling.

Summary:
`buildASTFromCodeWithArgs()` was creating a memory buffer referencing a
stack-allocated string.  This diff changes the implementation to copy the code
string into the memory buffer so that said buffer owns the memory.

Patch by Yitzhak Mandelbaum.

Reviewers: alexfh

Reviewed By: alexfh

Subscribers: cfe-commits, EricWF

Differential Revision: https://reviews.llvm.org/D55765

llvm-svn: 350638

1 files changed, 4 insertions, 1 deletions

diff --git a/clang/unittests/Analysis/ExprMutationAnalyzerTest.cpp b/clang/unittests/Analysis/ExprMutationAnalyzerTest.cpp
index 9c6bc783b33..68c921e4398 100644
--- a/clang/unittests/Analysis/ExprMutationAnalyzerTest.cpp
+++ b/clang/unittests/Analysis/ExprMutationAnalyzerTest.cpp
@@ -11,6 +11,7 @@
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/ASTMatchers/ASTMatchers.h"
 #include "clang/Tooling/Tooling.h"
+#include "llvm/ADT/SmallString.h"
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 #include <cctype>
@@ -32,7 +33,9 @@ using StmtMatcher = internal::Matcher<Stmt>;
 std::unique_ptr<ASTUnit>
 buildASTFromCodeWithArgs(const Twine &Code,
                          const std::vector<std::string> &Args) {
-  auto AST = tooling::buildASTFromCodeWithArgs(Code, Args);
+  SmallString<1024> CodeStorage;
+  auto AST =
+      tooling::buildASTFromCodeWithArgs(Code.toStringRef(CodeStorage), Args);
   EXPECT_FALSE(AST->getDiagnostics().hasErrorOccurred());
   return AST;
 }