[asan] initialize fake_stack lazily and increase its maximal size. This makes -fsanitize=address,use-after-return more robust: all SPEC tests pass now. In the default mode thread stacks become a bit smaller.

llvm-svn: 184934

5 files changed, 29 insertions, 19 deletions

diff --git a/compiler-rt/lib/asan/asan_fake_stack.cc b/compiler-rt/lib/asan/asan_fake_stack.cc
index 2fe8ef4fe68..55eddb6ebd8 100644
--- a/compiler-rt/lib/asan/asan_fake_stack.cc
+++ b/compiler-rt/lib/asan/asan_fake_stack.cc
@@ -17,11 +17,6 @@
 
 namespace __asan {
 
-FakeStack::FakeStack() {
-  CHECK(REAL(memset));
-  REAL(memset)(this, 0, sizeof(*this));
-}
-
 bool FakeStack::AddrIsInSizeClass(uptr addr, uptr size_class) {
   uptr mem = allocated_size_classes_[size_class];
   uptr size = ClassMmapSize(size_class);
@@ -170,7 +165,8 @@ uptr __asan_stack_malloc(uptr size, uptr real_stack) {
     // TSD is gone, use the real stack.
     return real_stack;
   }
-  uptr ptr = t->fake_stack().AllocateStack(size, real_stack);
+  t->LazyInitFakeStack();
+  uptr ptr = t->fake_stack()->AllocateStack(size, real_stack);
   // Printf("__asan_stack_malloc %p %zu %p\n", ptr, size, real_stack);
   return ptr;
 }
diff --git a/compiler-rt/lib/asan/asan_fake_stack.h b/compiler-rt/lib/asan/asan_fake_stack.h
index a11a3dbe286..6a5e5f63229 100644
--- a/compiler-rt/lib/asan/asan_fake_stack.h
+++ b/compiler-rt/lib/asan/asan_fake_stack.h
@@ -71,8 +71,6 @@ class FakeFrameLifo {
 // call to __asan_stack_malloc.
 class FakeStack {
  public:
-  FakeStack();
-  explicit FakeStack(LinkerInitialized x) : call_stack_(x) {}
   void Init(uptr stack_size);
   void StopUsingFakeStack() { alive_ = false; }
   void Cleanup();
@@ -88,7 +86,7 @@ class FakeStack {
   static const uptr kMaxStackMallocSize = 1 << kMaxStackFrameSizeLog;
   static const uptr kNumberOfSizeClasses =
       kMaxStackFrameSizeLog - kMinStackFrameSizeLog + 1;
-  static const uptr kMaxRecursionDepth = 1023;
+  static const uptr kMaxRecursionDepth = 15000;
 
   bool AddrIsInSizeClass(uptr addr, uptr size_class);
 
@@ -112,6 +110,8 @@ class FakeStack {
   FakeFrameLifo<kMaxRecursionDepth> call_stack_;
 };
 
+COMPILER_CHECK(sizeof(FakeStack) <= (1 << 17));
+
 }  // namespace __asan
 
 #endif  // ASAN_FAKE_STACK_H
diff --git a/compiler-rt/lib/asan/asan_report.cc b/compiler-rt/lib/asan/asan_report.cc
index f8cc906d3d1..9c46b49e47f 100644
--- a/compiler-rt/lib/asan/asan_report.cc
+++ b/compiler-rt/lib/asan/asan_report.cc
@@ -481,7 +481,8 @@ class ScopedInErrorReport {
       // in case we call an instrumented function from a symbolizer.
       AsanThread *curr_thread = GetCurrentThread();
       CHECK(curr_thread);
-      curr_thread->fake_stack().StopUsingFakeStack();
+      if (curr_thread->fake_stack())
+        curr_thread->fake_stack()->StopUsingFakeStack();
     }
   }
   // Destructor is NORETURN, as functions that report errors are.
diff --git a/compiler-rt/lib/asan/asan_thread.cc b/compiler-rt/lib/asan/asan_thread.cc
index ef43eb684d1..39153bf878d 100644
--- a/compiler-rt/lib/asan/asan_thread.cc
+++ b/compiler-rt/lib/asan/asan_thread.cc
@@ -102,7 +102,7 @@ void AsanThread::Destroy() {
   // some code may still be executing in later TSD destructors
   // and we don't want it to have any poisoned stack.
   ClearShadowForThreadStackAndTLS();
-  fake_stack().Cleanup();
+  DeleteFakeStack();
   uptr size = RoundUpTo(sizeof(AsanThread), GetPageSizeCached());
   UnmapOrDie(this, size);
 }
@@ -118,7 +118,7 @@ void AsanThread::Init() {
            tid(), (void*)stack_bottom_, (void*)stack_top_,
            stack_top_ - stack_bottom_, &local);
   }
-  fake_stack_.Init(stack_size());
+  fake_stack_ = 0;  // Will be initialized lazily if needed.
   AsanPlatformThreadInit();
 }
 
@@ -166,8 +166,8 @@ const char *AsanThread::GetFrameNameByAddr(uptr addr, uptr *offset,
   uptr bottom = 0;
   if (AddrIsInStack(addr)) {
     bottom = stack_bottom();
-  } else {
-    bottom = fake_stack().AddrIsInFakeStack(addr);
+  } else if (fake_stack()) {
+    bottom = fake_stack()->AddrIsInFakeStack(addr);
     CHECK(bottom);
     *offset = addr - bottom;
     *frame_pc = ((uptr*)bottom)[2];
@@ -203,9 +203,11 @@ static bool ThreadStackContainsAddress(ThreadContextBase *tctx_base,
                                        void *addr) {
   AsanThreadContext *tctx = static_cast<AsanThreadContext*>(tctx_base);
   AsanThread *t = tctx->thread;
-  return (t && t->fake_stack().StackSize() &&
-          (t->fake_stack().AddrIsInFakeStack((uptr)addr) ||
-           t->AddrIsInStack((uptr)addr)));
+  if (!t) return false;
+  if (t->AddrIsInStack((uptr)addr)) return true;
+  if (t->fake_stack() && t->fake_stack()->AddrIsInFakeStack((uptr)addr))
+    return true;
+  return false;
 }
 
 AsanThread *GetCurrentThread() {
diff --git a/compiler-rt/lib/asan/asan_thread.h b/compiler-rt/lib/asan/asan_thread.h
index bf08818da04..8aac20279a4 100644
--- a/compiler-rt/lib/asan/asan_thread.h
+++ b/compiler-rt/lib/asan/asan_thread.h
@@ -75,7 +75,18 @@ class AsanThread {
     return addr >= stack_bottom_ && addr < stack_top_;
   }
 
-  FakeStack &fake_stack() { return fake_stack_; }
+  void LazyInitFakeStack() {
+    if (fake_stack_) return;
+    fake_stack_ = (FakeStack*)MmapOrDie(sizeof(FakeStack), "FakeStack");
+    fake_stack_->Init(stack_size());
+  }
+  void DeleteFakeStack() {
+    if (!fake_stack_) return;
+    fake_stack_->Cleanup();
+    UnmapOrDie(fake_stack_, sizeof(FakeStack));
+  }
+  FakeStack *fake_stack() { return fake_stack_; }
+
   AsanThreadLocalMallocStorage &malloc_storage() { return malloc_storage_; }
   AsanStats &stats() { return stats_; }
 
@@ -91,7 +102,7 @@ class AsanThread {
   uptr tls_begin_;
   uptr tls_end_;
 
-  FakeStack fake_stack_;
+  FakeStack *fake_stack_;
   AsanThreadLocalMallocStorage malloc_storage_;
   AsanStats stats_;
 };