[HWASAN] Fix __sanitizer_get_allocated_{begin,size}

[vitalybuka]

Summary

HWASAN_ALIASING_MODE needs to untag only
primary allocator pointers.

compiler-rt/lib/hwasan/hwasan_allocator.cpp

HwasanChunkView FindHeapChunkByAddress(uptr address) {
   if (!block)
     return HwasanChunkView();
   Metadata *metadata =
       reinterpret_cast<Metadata*>(allocator.GetMetaData(block));
   return HwasanChunkView(reinterpret_cast<uptr>(block), metadata);
 }
 
 static const void *AllocationBegin(const void *p) {
-  const void *untagged_ptr = UntagPtr(p);
+  const void *untagged_ptr =
+      __hwasan::InTaggableRegion(reinterpret_cast<uptr>(p)) ? UntagPtr(p) : p;
   if (!untagged_ptr)
     return nullptr;
 
   const void *beg = allocator.GetBlockBegin(untagged_ptr);
   if (!beg)
     return nullptr;
 
   Metadata *b = (Metadata *)allocator.GetMetaData(beg);
   if (b->GetRequestedSize() == 0)
     return nullptr;
 
   tag_t tag = GetTagFromPointer((uptr)p);
   return (const void *)AddTagToPointer((uptr)beg, tag);
 }
 
-static uptr AllocationSize(const void *tagged_ptr) {
-  const void *untagged_ptr = UntagPtr(tagged_ptr);
+static uptr AllocationSize(const void *p) {
+  const void *untagged_ptr =
+      __hwasan::InTaggableRegion(reinterpret_cast<uptr>(p)) ? UntagPtr(p) : p;
   if (!untagged_ptr) return 0;
   const void *beg = allocator.GetBlockBegin(untagged_ptr);
-  Metadata *b = (Metadata *)allocator.GetMetaData(untagged_ptr);
-  if (beg != untagged_ptr) return 0;
+  if (!beg)
+    return 0;
+  Metadata *b = (Metadata *)allocator.GetMetaData(beg);
   return b->GetRequestedSize();
 }
 
 void *hwasan_malloc(uptr size, StackTrace *stack) {
   return SetErrnoOnNull(HwasanAllocate(stack, size, sizeof(u64), false));
 }
 
 void *hwasan_calloc(uptr nmemb, uptr size, StackTrace *stack) {

compiler-rt/test/sanitizer_common/TestCases/Linux/malloc_usable_size.c

 // RUN: %clang -O2 %s -o %t && %run %t
 
 // Must not be implemented, no other reason to install interceptors.
 // XFAIL: ubsan
 
-// FIXME: Implement.
-// XFAIL: hwasan-aliasing
-
 #include <assert.h>
 #include <malloc.h>
 #include <sanitizer/allocator_interface.h>
 #include <stdlib.h>
 
 void *p;
 
 int main() {

compiler-rt/test/sanitizer_common/TestCases/get_allocated_begin.cpp

 // RUN: %clangxx -O0 -g %s -o %t && %run %t
 
 // Must not be implemented, no other reason to install interceptors.
 // XFAIL: ubsan
 
-// FIXME: Implement.
-// XFAIL: hwasan-aliasing
-
 #include <assert.h>
 #include <sanitizer/allocator_interface.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 // Based on lib/msan/tests/msan_test.cpp::get_allocated_size_and_ownership
 int main(void) {