[ASan] Add sleep_before_init flag

Also do a little bit of refactoring instead of just copy&paste.

Differential Revision: https://reviews.llvm.org/D126037

compiler-rt/lib/asan/asan_flags.inc

@@ -83,6 +83,10 @@ ASAN_FLAG(
     int, sleep_after_init, 0,
     "Number of seconds to sleep after AddressSanitizer is initialized. "
     "Useful for debugging purposes (e.g. when one needs to attach gdb).")
+ASAN_FLAG(
+    int, sleep_before_init, 0,
+    "Number of seconds to sleep before AddressSanitizer starts initializing. "
+    "Useful for debugging purposes (e.g. when one needs to attach gdb).")
 ASAN_FLAG(bool, check_malloc_usable_size, true,
           "Allows the users to work around the bug in Nvidia drivers prior to "
           "295.*.")

compiler-rt/lib/asan/asan_rtl.cpp

@@ -51,10 +51,9 @@ static void AsanDie() {
   }
   if (common_flags()->print_module_map >= 1)
     DumpProcessMap();
-  if (flags()->sleep_before_dying) {
-    Report("Sleeping for %d second(s)\n", flags()->sleep_before_dying);
-    SleepForSeconds(flags()->sleep_before_dying);
-  }
+
+  WaitForDebugger(flags()->sleep_before_dying, "before dying");
+
   if (flags()->unmap_shadow_on_exit) {
     if (kMidMemBeg) {
       UnmapOrDie((void*)kLowShadowBeg, kMidMemBeg - kLowShadowBeg);
@@ -386,6 +385,8 @@ static void AsanInitInternal() {
   // initialization steps look at flags().
   InitializeFlags();
 
+  WaitForDebugger(flags()->sleep_before_init, "before init");
+
   // Stop performing init at this point if we are being loaded via
   // dlopen() and the platform supports it.
   if (SANITIZER_SUPPORTS_INIT_FOR_DLOPEN && UNLIKELY(HandleDlopenInit())) {
@@ -497,10 +498,7 @@ static void AsanInitInternal() {
 
   VReport(1, "AddressSanitizer Init done\n");
 
-  if (flags()->sleep_after_init) {
-    Report("Sleeping for %d second(s)\n", flags()->sleep_after_init);
-    SleepForSeconds(flags()->sleep_after_init);
-  }
+  WaitForDebugger(flags()->sleep_after_init, "after init");
 }
 
 // Initialize as requested from some part of ASan runtime library (interceptors,

compiler-rt/lib/sanitizer_common/sanitizer_common.cpp

@@ -351,6 +351,13 @@ void SleepForSeconds(unsigned seconds) {
 }
 void SleepForMillis(unsigned millis) { internal_usleep((u64)millis * 1000); }
 
+void WaitForDebugger(unsigned seconds, const char *label) {
+  if (seconds) {
+    Report("Sleeping for %u second(s) %s\n", seconds, label);
+    SleepForSeconds(seconds);
+  }
+}
+
 } // namespace __sanitizer
 
 using namespace __sanitizer;

compiler-rt/lib/sanitizer_common/sanitizer_common.h

@@ -294,6 +294,7 @@ void InitTlsSize();
 uptr GetTlsSize();
 
 // Other
+void WaitForDebugger(unsigned seconds, const char *label);
 void SleepForSeconds(unsigned seconds);
 void SleepForMillis(unsigned millis);
 u64 NanoTime();

compiler-rt/test/asan/TestCases/sleep_after_init.c

@@ -1,10 +0,0 @@
-// RUN: %clang_asan -O2 %s -o %t
-// RUN: %env_asan_opts=sleep_after_init=1 not %run %t 2>&1 | FileCheck %s
-
-#include <stdlib.h>
-int main() {
-  // CHECK: Sleeping for 1 second
-  char *x = (char*)malloc(10 * sizeof(char));
-  free(x);
-  return x[5];
-}

compiler-rt/test/asan/TestCases/sleep_before_dying.c

@@ -1,10 +0,0 @@
-// RUN: %clang_asan -O2 %s -o %t
-// RUN: %env_asan_opts=sleep_before_dying=1 not %run %t 2>&1 | FileCheck %s
-
-#include <stdlib.h>
-int main() {
-  char *x = (char*)malloc(10 * sizeof(char));
-  free(x);
-  return x[5];
-  // CHECK: Sleeping for 1 second
-}

compiler-rt/test/asan/TestCases/sleep_for_debugger.c

@@ -0,0 +1,17 @@
+// RUN: %clang_asan -O2 %s -o %t
+// RUN: %env_asan_opts=verbosity=1:sleep_before_init=1:sleep_after_init=1:sleep_before_dying=1 not %run %t 2>&1 | FileCheck %s
+
+#include <stdlib.h>
+
+int main() {
+  char *x = (char*)malloc(10 * sizeof(char));
+  free(x);
+  return x[5];
+}
+
+// CHECK: Sleeping for 1 second(s) before init
+// CHECK: AddressSanitizer Init done
+// CHECK: Sleeping for 1 second(s) after init
+// CHECK: ERROR: AddressSanitizer
+// CHECK: ABORTING
+// CHECK: Sleeping for 1 second(s) before dying