[flang][unittests] Fix buffer overrun in FrontendActionTest

[kparzysz]

When SmallVector<char> is used as a backing storage, it can't be assumed to end with a \x0. When creating a StringRef from it, pass the length explicitly.

This was detected by address sanitizer.

[llvmbot]

@llvm/pr-subscribers-flang-driver

Author: Krzysztof Parzyszek (kparzysz)

Changes

When SmallVector<char> is used as a backing storage, it can't be assumed to end with a \x0. When creating a StringRef from it, pass the length explicitly.

This was detected by address sanitizer.

---

Full diff: https://github.com/llvm/llvm-project/pull/84381.diff

1 Files Affected:

• (modified) flang/unittests/Frontend/FrontendActionTest.cpp (+3-2)

diff --git a/flang/unittests/Frontend/FrontendActionTest.cpp b/flang/unittests/Frontend/FrontendActionTest.cpp
index 6ec15832d96d3c..123f428cc8b40b 100644
--- a/flang/unittests/Frontend/FrontendActionTest.cpp
+++ b/flang/unittests/Frontend/FrontendActionTest.cpp
@@ -198,7 +198,7 @@ TEST_F(FrontendActionTest, EmitLLVM) {
   EXPECT_TRUE(success);
   EXPECT_TRUE(!outputFileBuffer.empty());
 
-  EXPECT_TRUE(llvm::StringRef(outputFileBuffer.data())
+  EXPECT_TRUE(llvm::StringRef(outputFileBuffer.begin(), outputFileBuffer.size())
                   .contains("define void @_QQmain()"));
 }
 
@@ -227,6 +227,7 @@ TEST_F(FrontendActionTest, EmitAsm) {
   EXPECT_TRUE(success);
   EXPECT_TRUE(!outputFileBuffer.empty());
 
-  EXPECT_TRUE(llvm::StringRef(outputFileBuffer.data()).contains("_QQmain"));
+  EXPECT_TRUE(llvm::StringRef(outputFileBuffer.begin(), outputFileBuffer.size())
+                  .contains("_QQmain"));
 }
 } // namespace

[banach-space]

LGTM, thanks!