[compiler-rt] [UBSan] leave BufferedStackTrace uninit

[fmayer]

Otherwise we have to memset 2040 bytes (255 * 8) for each call

[llvmbot]

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

Author: Florian Mayer (fmayer)

Changes

Otherwise we have to memset 2040 bytes (255 * 8) for each call

---

Full diff: https://github.com/llvm/llvm-project/pull/102253.diff

2 Files Affected:

• (modified) compiler-rt/lib/ubsan/ubsan_diag.cpp (+1-1)
• (modified) compiler-rt/lib/ubsan/ubsan_diag_standalone.cpp (+1-1)

diff --git a/compiler-rt/lib/ubsan/ubsan_diag.cpp b/compiler-rt/lib/ubsan/ubsan_diag.cpp
index 1625dfe89eb11..2146ed3c27287 100644
--- a/compiler-rt/lib/ubsan/ubsan_diag.cpp
+++ b/compiler-rt/lib/ubsan/ubsan_diag.cpp
@@ -47,7 +47,7 @@ static void MaybePrintStackTrace(uptr pc, uptr bp) {
   if (!flags()->print_stacktrace)
     return;
 
-  BufferedStackTrace stack;
+  UNINITIALIZED BufferedStackTrace stack;
   ubsan_GetStackTrace(&stack, kStackTraceMax, pc, bp, nullptr,
                 common_flags()->fast_unwind_on_fatal);
   stack.Print();
diff --git a/compiler-rt/lib/ubsan/ubsan_diag_standalone.cpp b/compiler-rt/lib/ubsan/ubsan_diag_standalone.cpp
index 5526ae0516504..03dfde8908dd9 100644
--- a/compiler-rt/lib/ubsan/ubsan_diag_standalone.cpp
+++ b/compiler-rt/lib/ubsan/ubsan_diag_standalone.cpp
@@ -29,7 +29,7 @@ extern "C" {
 SANITIZER_INTERFACE_ATTRIBUTE
 void __sanitizer_print_stack_trace() {
   GET_CURRENT_PC_BP;
-  BufferedStackTrace stack;
+  UNINITIALIZED BufferedStackTrace stack;
   stack.Unwind(pc, bp, nullptr, common_flags()->fast_unwind_on_fatal);
   stack.Print();
 }