[sanitizer] Internalize .preinit_array variables

We can use an internal linkage variable to make it clear the variable is
not exported. The special section .preinit_array is a GC root.

Pull Request: https://github.com/llvm/llvm-project/pull/98584

compiler-rt/lib/asan/asan_preinit.cpp

@@ -15,10 +15,8 @@
 using namespace __asan;
 
 #if SANITIZER_CAN_USE_PREINIT_ARRAY
-  // The symbol is called __local_asan_preinit, because it's not intended to be
-  // exported.
-  // This code linked into the main executable when -fsanitize=address is in
-  // the link flags. It can only use exported interface functions.
-  __attribute__((section(".preinit_array"), used))
-  void (*__local_asan_preinit)(void) = __asan_init;
+// This section is linked into the main executable when -fsanitize=hwaddress is
+// specified to perform initialization at a very early stage.
+__attribute__((section(".preinit_array"), used)) static auto preinit =
+    __asan_init;
 #endif

compiler-rt/lib/hwasan/hwasan_preinit.cpp

@@ -14,10 +14,8 @@
 #include "sanitizer_common/sanitizer_internal_defs.h"
 
 #if SANITIZER_CAN_USE_PREINIT_ARRAY
-// The symbol is called __local_hwasan_preinit, because it's not intended to
-// be exported.
-// This code linked into the main executable when -fsanitize=hwaddress is in
-// the link flags. It can only use exported interface functions.
-__attribute__((section(".preinit_array"), used)) static void (
-    *__local_hwasan_preinit)(void) = __hwasan_init;
+// This section is linked into the main executable when -fsanitize=hwaddress is
+// specified to perform initialization at a very early stage.
+__attribute__((section(".preinit_array"), used)) static auto preinit =
+    __hwasan_init;
 #endif

compiler-rt/lib/lsan/lsan_preinit.cpp

@@ -14,8 +14,8 @@
 #include "lsan.h"
 
 #if SANITIZER_CAN_USE_PREINIT_ARRAY
-  // We force __lsan_init to be called before anyone else by placing it into
-  // .preinit_array section.
-  __attribute__((section(".preinit_array"), used))
-  void (*__local_lsan_preinit)(void) = __lsan_init;
+// This section is linked into the main executable when -fsanitize=leak is
+// specified to perform initialization at a very early stage.
+__attribute__((section(".preinit_array"), used)) static auto preinit =
+    __lsan_init;
 #endif

compiler-rt/lib/memprof/memprof_preinit.cpp

@@ -15,9 +15,8 @@
 using namespace __memprof;
 
 #if SANITIZER_CAN_USE_PREINIT_ARRAY
-// The symbol is called __local_memprof_preinit, because it's not intended to
-// be exported. This code linked into the main executable when -fmemory-profile
-// is in the link flags. It can only use exported interface functions.
-__attribute__((section(".preinit_array"),
-               used)) void (*__local_memprof_preinit)(void) = __memprof_preinit;
+// This section is linked into the main executable when -fmemory-profile is
+// specified to perform initialization at a very early stage.
+__attribute__((section(".preinit_array"), used)) static auto preinit =
+    __memprof_preinit;
 #endif

compiler-rt/lib/rtsan/rtsan_preinit.cpp

@@ -13,11 +13,9 @@
 
 #if SANITIZER_CAN_USE_PREINIT_ARRAY
 
-// The symbol is called __local_rtsan_preinit, because it's not intended to be
-// exported.
-// This code is linked into the main executable when -fsanitize=realtime is in
-// the link flags. It can only use exported interface functions.
-__attribute__((section(".preinit_array"),
-               used)) void (*__local_rtsan_preinit)(void) = __rtsan_init;
+// This section is linked into the main executable when -fsanitize=realtime is
+// specified to perform initialization at a very early stage.
+__attribute__((section(".preinit_array"), used)) static auto preinit =
+    __rtsan_init;
 
 #endif

compiler-rt/lib/tsan/rtl/tsan_preinit.cpp

@@ -16,11 +16,9 @@
 
 #if SANITIZER_CAN_USE_PREINIT_ARRAY
 
-// The symbol is called __local_tsan_preinit, because it's not intended to be
-// exported.
-// This code linked into the main executable when -fsanitize=thread is in
-// the link flags. It can only use exported interface functions.
-__attribute__((section(".preinit_array"), used))
-void (*__local_tsan_preinit)(void) = __tsan_init;
+// This section is linked into the main executable when -fsanitize=thread is
+// specified to perform initialization at a very early stage.
+__attribute__((section(".preinit_array"), used)) static auto preinit =
+    __tsan_init;
 
 #endif

compiler-rt/lib/ubsan/ubsan_init_standalone_preinit.cpp

@@ -30,6 +30,6 @@ static void PreInitAsStandalone() {
 
 } // namespace __ubsan
 
-__attribute__((section(".preinit_array"), used)) void (*__local_ubsan_preinit)(
-    void) = __ubsan::PreInitAsStandalone;
+__attribute__((section(".preinit_array"), used)) static auto preinit =
+    __ubsan::PreInitAsStandalone;
 #endif // SANITIZER_CAN_USE_PREINIT_ARRAY

compiler-rt/test/tsan/Linux/check_preinit.cpp

@@ -2,7 +2,7 @@
 // RUN:  %t.so && \
 // RUN:   %clang_tsan -O1 %s %t.so -o %t && %run %t 2>&1 | FileCheck %s
 // RUN: llvm-objdump -t %t | FileCheck %s --check-prefix=CHECK-DUMP
-// CHECK-DUMP:  {{[.]preinit_array.*__local_tsan_preinit}}
+// CHECK-DUMP:  {{[.]preinit_array.*preinit}}
 
 // SANITIZER_CAN_USE_PREINIT_ARRAY is undefined on android.
 // UNSUPPORTED: android