From 8b062b61606270950645d73b68036c9ab2c7c4bc Mon Sep 17 00:00:00 2001
From: Kostya Kortchinsky <kostyak@google.com>
Date: Wed, 16 Jun 2021 10:51:51 -0700
Subject: [PATCH] [scudo] Ensure proper allocator alignment in TSD test

The `MockAllocator` used in `ScudoTSDTest` wasn't allocated
properly aligned, which resulted in the `TSDs` of the shared
registry not being aligned either. This lead to some failures
like: https://reviews.llvm.org/D103119#2822008

This changes how the `MockAllocator` is allocated, same as
Vitaly did in the combined tests, properly aligning it, which
results in the `TSDs` being aligned as well.

Add a `DCHECK` in the shared registry to check that it is.

Differential Revision: https://reviews.llvm.org/D104402
---
 compiler-rt/lib/scudo/standalone/primary32.h        | 2 +-
 compiler-rt/lib/scudo/standalone/primary64.h        | 1 +
 compiler-rt/lib/scudo/standalone/quarantine.h       | 2 ++
 compiler-rt/lib/scudo/standalone/tests/tsd_test.cpp | 9 +++++++++
 compiler-rt/lib/scudo/standalone/tsd.h              | 2 ++
 5 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/compiler-rt/lib/scudo/standalone/primary32.h b/compiler-rt/lib/scudo/standalone/primary32.h
index 36ae083cfc73..326c10a32a85 100644
--- a/compiler-rt/lib/scudo/standalone/primary32.h
+++ b/compiler-rt/lib/scudo/standalone/primary32.h
@@ -67,8 +67,8 @@ public:
     if (SCUDO_TRUSTY)
       reportError("SizeClassAllocator32 is not supported on Trusty");
 
+    DCHECK(isAligned(reinterpret_cast<uptr>(this), alignof(ThisT)));
     PossibleRegions.init();
-
     u32 Seed;
     const u64 Time = getMonotonicTime();
     if (!getRandom(reinterpret_cast<void *>(&Seed), sizeof(Seed)))
diff --git a/compiler-rt/lib/scudo/standalone/primary64.h b/compiler-rt/lib/scudo/standalone/primary64.h
index 27634c96c71e..13420bf3d222 100644
--- a/compiler-rt/lib/scudo/standalone/primary64.h
+++ b/compiler-rt/lib/scudo/standalone/primary64.h
@@ -59,6 +59,7 @@ public:
   static bool canAllocate(uptr Size) { return Size <= SizeClassMap::MaxSize; }
 
   void init(s32 ReleaseToOsInterval) {
+    DCHECK(isAligned(reinterpret_cast<uptr>(this), alignof(ThisT)));
     DCHECK_EQ(PrimaryBase, 0U);
     // Reserve the space required for the Primary.
     PrimaryBase = reinterpret_cast<uptr>(
diff --git a/compiler-rt/lib/scudo/standalone/quarantine.h b/compiler-rt/lib/scudo/standalone/quarantine.h
index 84eb90cc0b3f..2d231c3a28db 100644
--- a/compiler-rt/lib/scudo/standalone/quarantine.h
+++ b/compiler-rt/lib/scudo/standalone/quarantine.h
@@ -170,8 +170,10 @@ private:
 template <typename Callback, typename Node> class GlobalQuarantine {
 public:
   typedef QuarantineCache<Callback> CacheT;
+  using ThisT = GlobalQuarantine<Callback, Node>;
 
   void init(uptr Size, uptr CacheSize) {
+    DCHECK(isAligned(reinterpret_cast<uptr>(this), alignof(ThisT)));
     DCHECK_EQ(atomic_load_relaxed(&MaxSize), 0U);
     DCHECK_EQ(atomic_load_relaxed(&MinSize), 0U);
     DCHECK_EQ(atomic_load_relaxed(&MaxCacheSize), 0U);
diff --git a/compiler-rt/lib/scudo/standalone/tests/tsd_test.cpp b/compiler-rt/lib/scudo/standalone/tests/tsd_test.cpp
index 35e579d5dc58..17387ee7c570 100644
--- a/compiler-rt/lib/scudo/standalone/tests/tsd_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/tsd_test.cpp
@@ -11,6 +11,8 @@
 #include "tsd_exclusive.h"
 #include "tsd_shared.h"
 
+#include <stdlib.h>
+
 #include <condition_variable>
 #include <mutex>
 #include <set>
@@ -40,6 +42,13 @@ public:
 
   bool isInitialized() { return Initialized; }
 
+  void *operator new(size_t Size) {
+    void *P = nullptr;
+    EXPECT_EQ(0, posix_memalign(&P, alignof(ThisT), Size));
+    return P;
+  }
+  void operator delete(void *P) { free(P); }
+
 private:
   bool Initialized = false;
   TSDRegistryT TSDRegistry;
diff --git a/compiler-rt/lib/scudo/standalone/tsd.h b/compiler-rt/lib/scudo/standalone/tsd.h
index e376df05af5e..b400a3b56da9 100644
--- a/compiler-rt/lib/scudo/standalone/tsd.h
+++ b/compiler-rt/lib/scudo/standalone/tsd.h
@@ -26,10 +26,12 @@ namespace scudo {
 template <class Allocator> struct alignas(SCUDO_CACHE_LINE_SIZE) TSD {
   typename Allocator::CacheT Cache;
   typename Allocator::QuarantineCacheT QuarantineCache;
+  using ThisT = TSD<Allocator>;
   u8 DestructorIterations = 0;
 
   void init(Allocator *Instance) {
     DCHECK_EQ(DestructorIterations, 0U);
+    DCHECK(isAligned(reinterpret_cast<uptr>(this), alignof(ThisT)));
     Instance->initCache(&Cache);
     DestructorIterations = PTHREAD_DESTRUCTOR_ITERATIONS;
   }