[PATCH] D38854: [scudo] Allow for non-Android Shared TSD platforms, part 2

[Kostya Kortchinsky via Phabricator via llvm-commits]

cryptoad created this revision.
Herald added a subscriber: srhines.

Follow up to https://reviews.llvm.org/D38826.

We introduce `pthread_{get,set}specific` versions of `{get,set}CurrentTSD` to
allow for non Android platforms to use the Shared TSD model.
We now allow `SCUDO_TSD_EXCLUSIVE` to be defined at compile time.

A couple of things:

- I know that `#if SANITIZER_ANDROID` is not ideal within a function, but in the end I feel it looks more compact and clean than going the .inc route; I am open to an alternative if anyone has one;
- `SCUDO_TSD_EXCLUSIVE=1` requires ELF TLS support (and not emutls as this uses malloc). I haven't found anything to enforce that, so it's currently not checked.


https://reviews.llvm.org/D38854

Files:
  lib/scudo/scudo_platform.h
  lib/scudo/scudo_tsd_shared.cpp
  lib/scudo/scudo_tsd_shared.inc


Index: lib/scudo/scudo_tsd_shared.inc
===================================================================
--- lib/scudo/scudo_tsd_shared.inc
+++ lib/scudo/scudo_tsd_shared.inc
@@ -17,8 +17,14 @@
 
 #if !SCUDO_TSD_EXCLUSIVE
 
+extern pthread_key_t PThreadKey;
+
 ALWAYS_INLINE ScudoTSD* getCurrentTSD() {
+#if SANITIZER_ANDROID
   return reinterpret_cast<ScudoTSD *>(*get_android_tls_ptr());
+#else
+  return reinterpret_cast<ScudoTSD *>(pthread_getspecific(PThreadKey));
+#endif  // SANITIZER_ANDROID
 }
 
 ALWAYS_INLINE void initThreadMaybe(bool MinimalInit = false) {
Index: lib/scudo/scudo_tsd_shared.cpp
===================================================================
--- lib/scudo/scudo_tsd_shared.cpp
+++ lib/scudo/scudo_tsd_shared.cpp
@@ -18,7 +18,7 @@
 namespace __scudo {
 
 static pthread_once_t GlobalInitialized = PTHREAD_ONCE_INIT;
-static pthread_key_t PThreadKey;
+pthread_key_t PThreadKey;
 
 static atomic_uint32_t CurrentIndex;
 static ScudoTSD *TSDs;
@@ -50,7 +50,11 @@
 }
 
 ALWAYS_INLINE void setCurrentTSD(ScudoTSD *TSD) {
+#if SANITIZER_ANDROID
   *get_android_tls_ptr() = reinterpret_cast<uptr>(TSD);
+#else
+  CHECK_EQ(pthread_setspecific(PThreadKey, reinterpret_cast<void *>(TSD)), 0);
+#endif  // SANITIZER_ANDROID
 }
 
 void initThread(bool MinimalInit) {
Index: lib/scudo/scudo_platform.h
===================================================================
--- lib/scudo/scudo_platform.h
+++ lib/scudo/scudo_platform.h
@@ -20,15 +20,17 @@
 # error "The Scudo hardened allocator is not supported on this platform."
 #endif
 
-#if SANITIZER_ANDROID || SANITIZER_FUCHSIA
+#ifndef SCUDO_TSD_EXCLUSIVE
+# if SANITIZER_ANDROID || SANITIZER_FUCHSIA
 // Android and Fuchsia use a pool of TSDs shared between threads.
-# define SCUDO_TSD_EXCLUSIVE 0
-#elif SANITIZER_LINUX && !SANITIZER_ANDROID
+#  define SCUDO_TSD_EXCLUSIVE 0
+# elif SANITIZER_LINUX && !SANITIZER_ANDROID
 // Non-Android Linux use an exclusive TSD per thread.
-# define SCUDO_TSD_EXCLUSIVE 1
-#else
-# error "No default TSD model defined for this platform."
-#endif  // SANITIZER_ANDROID || SANITIZER_FUCHSIA
+#  define SCUDO_TSD_EXCLUSIVE 1
+# else
+#  error "No default TSD model defined for this platform."
+# endif  // SANITIZER_ANDROID || SANITIZER_FUCHSIA
+#endif  // SCUDO_TSD_EXCLUSIVE
 
 namespace __scudo {
 


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