[llvm-branch-commits] [compiler-rt] release/21.x: [scudo] Make Ptr volatile so that the malloc and free calls are not optimized out (#149944) (PR #151201)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: None (llvmbot)

<details>
<summary>Changes</summary>

Backport fcdcc4ea7ac960c79246b3bd428f14ea350e63e2

Requested by: @<!-- -->mgorny

---
Full diff: https://github.com/llvm/llvm-project/pull/151201.diff


1 Files Affected:

- (modified) compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp (+2-1) 


``````````diff
diff --git a/compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp b/compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp
index 05065444a70c5..612317b3c3293 100644
--- a/compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp
@@ -183,7 +183,8 @@ TEST_F(ScudoWrappersCDeathTest, Malloc) {
   // process doing free(P) is not a double free.
   EXPECT_DEATH(
       {
-        void *Ptr = malloc(Size);
+        // Note: volatile here prevents the calls from being optimized out.
+        void *volatile Ptr = malloc(Size);
         free(Ptr);
         free(Ptr);
       },

``````````

</details>


https://github.com/llvm/llvm-project/pull/151201