From 0b3458054177629ef0afde4e57641ed91e168428 Mon Sep 17 00:00:00 2001
From: Lindsay Stewart <slindsay@amazon.com>
Date: Thu, 15 Jun 2023 00:01:23 +0000
Subject: [PATCH] PR comments: rework compiler flags

---
 CMakeLists.txt     | 12 +++++-------
 utils/s2n_atomic.c |  6 +++---
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 30ac35fbff4..bc8e6554842 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -221,6 +221,11 @@ if(S2N_UNSAFE_FUZZING_MODE)
     target_compile_options(${PROJECT_NAME} PRIVATE -fsanitize-coverage=trace-pc-guard -fsanitize=address,undefined,leak -fuse-ld=gold -DS2N_ADDRESS_SANITIZER=1)
 endif()
 
+if(TSAN)
+    target_compile_options(${PROJECT_NAME} PUBLIC -fsanitize=thread -DS2N_THREAD_SANITIZER=1)
+    target_link_options(${PROJECT_NAME} PUBLIC -fsanitize=thread)
+endif()
+
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules")
 
 if (NOT $ENV{S2N_LIBCRYPTO} MATCHES "awslc")
@@ -352,13 +357,6 @@ if (NOT S2N_EXECINFO_AVAILABLE)
 endif()
 feature_probe_result(S2N_STACKTRACE ${S2N_STACKTRACE})
 
-if(TSAN)
-    target_compile_options(${PROJECT_NAME} PUBLIC -fsanitize=thread)
-    target_link_options(${PROJECT_NAME} PUBLIC -fsanitize=thread)
-    # For now, only enable real atomics for TSAN
-    feature_probe_result(S2N_ATOMIC_ENABLED ${S2N_ATOMIC_SUPPORTED})
-endif()
-
 set(S2N_KYBER512R3_AVX2_BMI2 FALSE)
 if(NOT S2N_NO_PQ_ASM)
     # Kyber Round-3 code has several different optimizations which require
diff --git a/utils/s2n_atomic.c b/utils/s2n_atomic.c
index 3fa931b7b6e..8496bd40732 100644
--- a/utils/s2n_atomic.c
+++ b/utils/s2n_atomic.c
@@ -21,7 +21,7 @@
 
 S2N_RESULT s2n_atomic_init()
 {
-#if S2N_ATOMIC_ENABLED
+#if S2N_ATOMIC_SUPPORTED && S2N_THREAD_SANITIZER
     RESULT_ENSURE(__atomic_always_lock_free(sizeof(s2n_atomic_bool), NULL), S2N_ERR_ATOMIC);
 #endif
     return S2N_RESULT_OK;
@@ -29,7 +29,7 @@ S2N_RESULT s2n_atomic_init()
 
 void s2n_atomic_store(s2n_atomic_bool *var, bool val)
 {
-#if S2N_ATOMIC_ENABLED
+#if S2N_ATOMIC_SUPPORTED && S2N_THREAD_SANITIZER
     sig_atomic_t input = val;
     __atomic_store(&var->val, &input, __ATOMIC_RELAXED);
 #else
@@ -39,7 +39,7 @@ void s2n_atomic_store(s2n_atomic_bool *var, bool val)
 
 bool s2n_atomic_load(s2n_atomic_bool *var)
 {
-#if S2N_ATOMIC_ENABLED
+#if S2N_ATOMIC_SUPPORTED && S2N_THREAD_SANITIZER
     sig_atomic_t result = 0;
     __atomic_load(&var->val, &result, __ATOMIC_RELAXED);
     return result;