[hwasan] Add a basic API.

Summary:
Add user tag manipulation functions:
  __hwasan_tag_memory
  __hwasan_tag_pointer
  __hwasan_print_shadow (very simple and ugly, for now)

Reviewers: vitalybuka, kcc

Subscribers: kubamracek, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D50746

1 files changed, 12 insertions, 0 deletions

diff --git a/compiler-rt/include/sanitizer/hwasan_interface.h b/compiler-rt/include/sanitizer/hwasan_interface.h
index 75d31a6c35f..9ca73bc1072 100644
--- a/compiler-rt/include/sanitizer/hwasan_interface.h
+++ b/compiler-rt/include/sanitizer/hwasan_interface.h
@@ -32,6 +32,18 @@ extern "C" {
   void __hwasan_enable_allocator_tagging(void);
   void __hwasan_disable_allocator_tagging(void);
 
+  // Mark region of memory with the given tag. Both address and size need to be
+  // 16-byte aligned.
+  void __hwasan_tag_memory(const volatile void *p, unsigned char tag,
+                           size_t size);
+
+  /// Set pointer tag. Previous tag is lost.
+  void *__hwasan_tag_pointer(const volatile void *p, unsigned char tag);
+
+  // Print shadow and origin for the memory range to stderr in a human-readable
+  // format.
+  void __hwasan_print_shadow(const volatile void *x, size_t size);
+
   int __sanitizer_posix_memalign(void **memptr, size_t alignment, size_t size);
   void * __sanitizer_memalign(size_t alignment, size_t size);
   void * __sanitizer_aligned_alloc(size_t alignment, size_t size);