[compiler-rt] [asan] Flush stderr/stdout in tests (PR #114084)

[Thurston Dang via llvm-commits]

https://github.com/thurstond created https://github.com/llvm/llvm-project/pull/114084

This is the ASan equivalent of https://github.com/llvm/llvm-project/pull/114083.

The x86_64_lam_qemu buildbots started failing
(https://lab.llvm.org/buildbot/#/builders/139/builds/5462/steps/2/logs/stdio). Based on the logs, it appears the HWASan check is correct but it did not match the stderr/stdout output. This patch attempts to fix the issue by flushing stderr/stdout as appropriate.

>From 74c20367cbe534e592b09ae4dcbefa9c0ee9f8d3 Mon Sep 17 00:00:00 2001
From: Thurston Dang <thurston at google.com>
Date: Tue, 29 Oct 2024 16:31:32 +0000
Subject: [PATCH] [asan] Flush stderr/stdout in tests

This is the ASan equivalent of https://github.com/llvm/llvm-project/pull/114083.

The x86_64_lam_qemu buildbots started failing
(https://lab.llvm.org/buildbot/#/builders/139/builds/5462/steps/2/logs/stdio).
Based on the logs, it appears the HWASan check is correct but it did not
match the stderr/stdout output. This patch attempts to fix the issue by
flushing stderr/stdout as appropriate.
---
 compiler-rt/test/asan/TestCases/Posix/ignore_free_hook.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/compiler-rt/test/asan/TestCases/Posix/ignore_free_hook.cpp b/compiler-rt/test/asan/TestCases/Posix/ignore_free_hook.cpp
index 87be90014d56e8..dfeb8ad5c7b53f 100644
--- a/compiler-rt/test/asan/TestCases/Posix/ignore_free_hook.cpp
+++ b/compiler-rt/test/asan/TestCases/Posix/ignore_free_hook.cpp
@@ -26,14 +26,17 @@ bool ignore_free = false;
 
 extern "C" {
 WEAK_ON_APPLE void __sanitizer_free_hook(const volatile void *ptr) {
-  if (ptr == glob_ptr)
+  if (ptr == glob_ptr) {
     fprintf(stderr, "Free Hook\n");
+    fflush(stderr);
+  }
 }
 
 WEAK_ON_APPLE int __sanitizer_ignore_free_hook(const volatile void *ptr) {
   if (ptr != glob_ptr)
     return 0;
   fprintf(stderr, ignore_free ? "Free Ignored\n" : "Free Respected\n");
+  fflush(stderr);
   return ignore_free;
 }
 } // extern "C"