[msan] MemorySanitizer runtime.

Initial commit of the MemorySanitizer runtime library.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@169858 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 107 insertions, 0 deletions

diff --git a/lib/msan/msan_allocator.cc b/lib/msan/msan_allocator.cc
new file mode 100644
index 000000000..5d865c30b
--- /dev/null
+++ b/lib/msan/msan_allocator.cc
@@ -0,0 +1,107 @@
+//===-- msan_allocator.cc --------------------------- ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of MemorySanitizer.
+//
+// MemorySanitizer allocator.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_allocator.h"
+#include "sanitizer_common/sanitizer_stackdepot.h"
+#include "msan.h"
+
+namespace __msan {
+
+struct Metadata {
+  uptr requested_size;
+};
+
+static const uptr kAllocatorSpace = 0x600000000000ULL;
+static const uptr kAllocatorSize   = 0x80000000000;  // 8T.
+static const uptr kMetadataSize  = sizeof(Metadata);
+
+typedef SizeClassAllocator64<kAllocatorSpace, kAllocatorSize, kMetadataSize,
+                             DefaultSizeClassMap> PrimaryAllocator;
+typedef SizeClassAllocatorLocalCache<PrimaryAllocator> AllocatorCache;
+typedef LargeMmapAllocator SecondaryAllocator;
+typedef CombinedAllocator<PrimaryAllocator, AllocatorCache,
+                          SecondaryAllocator> Allocator;
+
+static THREADLOCAL AllocatorCache cache;
+static Allocator allocator;
+
+static int inited = 0;
+
+static inline void Init() {
+  if (inited) return;
+  __msan_init();
+  inited = true;  // this must happen before any threads are created.
+  allocator.Init();
+}
+
+static void *MsanAllocate(StackTrace *stack, uptr size,
+                          uptr alignment, bool zeroise) {
+  Init();
+  void *res = allocator.Allocate(&cache, size, alignment, false);
+  Metadata *meta = reinterpret_cast<Metadata*>(allocator.GetMetaData(res));
+  meta->requested_size = size;
+  if (zeroise)
+    __msan_clear_and_unpoison(res, size);
+  else if (flags()->poison_in_malloc)
+    __msan_poison(res, size);
+  if (__msan_get_track_origins()) {
+    u32 stack_id = StackDepotPut(stack->trace, stack->size);
+    CHECK(stack_id);
+    CHECK_EQ((stack_id >> 31), 0);  // Higher bit is occupied by stack origins.
+    __msan_set_origin(res, size, stack_id);
+  }
+  return res;
+}
+
+void MsanDeallocate(void *p) {
+  CHECK(p);
+  Init();
+  Metadata *meta = reinterpret_cast<Metadata*>(allocator.GetMetaData(p));
+  uptr size = meta->requested_size;
+  // This memory will not be reused by anyone else, so we are free to keep it
+  // poisoned.
+  __msan_poison(p, size);
+  if (__msan_get_track_origins())
+    __msan_set_origin(p, size, -1);
+  allocator.Deallocate(&cache, p);
+}
+
+void *MsanReallocate(StackTrace *stack, void *old_p, uptr new_size,
+                     uptr alignment, bool zeroise) {
+  if (!old_p)
+    return MsanAllocate(stack, new_size, alignment, zeroise);
+  if (!new_size) {
+    MsanDeallocate(old_p);
+    return 0;
+  }
+  Metadata *meta = reinterpret_cast<Metadata*>(allocator.GetMetaData(old_p));
+  uptr old_size = meta->requested_size;
+  uptr actually_allocated_size = allocator.GetActuallyAllocatedSize(old_p);
+  if (new_size <= actually_allocated_size) {
+    // We are not reallocating here.
+    meta->requested_size = new_size;
+    if (new_size > old_size)
+      __msan_poison((char*)old_p + old_size, new_size - old_size);
+    return old_p;
+  }
+  uptr memcpy_size = Min(new_size, old_size);
+  void *new_p = MsanAllocate(stack, new_size, alignment, zeroise);
+  // Printf("realloc: old_size %zd new_size %zd\n", old_size, new_size);
+  if (new_p)
+    __msan_memcpy(new_p, old_p, memcpy_size);
+  MsanDeallocate(old_p);
+  return new_p;
+}
+
+}  // namespace __msan