[compiler-rt] r332792 - Align ClearShadowForThreadStackAndTLS for NetBSD/i386

[Kamil Rytarowski via llvm-commits]

Author: kamil
Date: Fri May 18 18:20:00 2018
New Revision: 332792

URL: http://llvm.org/viewvc/llvm-project?rev=332792&view=rev
Log:
Align ClearShadowForThreadStackAndTLS for NetBSD/i386

Summary:
The static TLS vector for the main thread on NetBSD/i386 can be
unaligned in terms of the shadow granularity. Align the start of it with
Round Down and end of it with Round Up operations for the shadow
granularity shift.

Example static TLS vector ranges on NetBSD/i386:
tls_begin_=0xfbee7244 tls_end_=0xfbee726c.

ClearShadowForThreadStackAndTLS() is called from the Main Thread
bootstrap functions.

This change restores the NetBSD x86 32-bit (i386) support.

Sponsored by <The NetBSD Foundation>

Reviewers: vitalybuka, joerg

Reviewed By: vitalybuka

Subscribers: kubamracek, llvm-commits, #sanitizers

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D46585

Modified:
    compiler-rt/trunk/lib/asan/asan_thread.cc

Modified: compiler-rt/trunk/lib/asan/asan_thread.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_thread.cc?rev=332792&r1=332791&r2=332792&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_thread.cc (original)
+++ compiler-rt/trunk/lib/asan/asan_thread.cc Fri May 18 18:20:00 2018
@@ -303,8 +303,13 @@ void AsanThread::SetThreadStackAndTls(co
 
 void AsanThread::ClearShadowForThreadStackAndTLS() {
   PoisonShadow(stack_bottom_, stack_top_ - stack_bottom_, 0);
-  if (tls_begin_ != tls_end_)
-    PoisonShadow(tls_begin_, tls_end_ - tls_begin_, 0);
+  if (tls_begin_ != tls_end_) {
+    uptr tls_begin_aligned = RoundDownTo(tls_begin_, SHADOW_GRANULARITY);
+    uptr tls_end_aligned = RoundUpTo(tls_end_, SHADOW_GRANULARITY);
+    FastPoisonShadowPartialRightRedzone(tls_begin_aligned,
+                                        tls_end_ - tls_begin_aligned,
+                                        tls_end_aligned - tls_end_, 0);
+  }
 }
 
 bool AsanThread::GetStackFrameAccessByAddr(uptr addr,