Update __sanitizer_get_allocated_begin to return const void*

D147005 introduced __sanitizer_get_allocated_begin, with a return
value of void*. This involved a few naughty casts that dropped the
const. This patch adds back the const qualifier.

Differential Revision: https://reviews.llvm.org/D147489

compiler-rt/include/sanitizer/allocator_interface.h

@@ -28,7 +28,7 @@ extern "C" {
 
   /* If a pointer lies within an allocation, it will return the start address
      of the allocation. Otherwise, it returns nullptr. */
-  void *__sanitizer_get_allocated_begin(const void *p);
+  const void *__sanitizer_get_allocated_begin(const void *p);
 
   /* Returns the number of bytes reserved for the pointer p.
      Requires (get_ownership(p) == true) or (p == 0). */

compiler-rt/lib/asan/asan_allocator.cpp

@@ -1164,7 +1164,7 @@ IgnoreObjectResult IgnoreObjectLocked(const void *p) {
 // ---------------------- Interface ---------------- {{{1
 using namespace __asan;
 
-void *AllocationBegin(const void *p) {
+const void *AllocationBegin(const void *p) {
   AsanChunk *m = __asan::instance.GetAsanChunkByAddr((uptr)p);
   if (!m)
     return nullptr;
@@ -1172,7 +1172,7 @@ void *AllocationBegin(const void *p) {
     return nullptr;
   if (m->UsedSize() == 0)
     return nullptr;
-  return (void *)(m->Beg());
+  return (const void *)(m->Beg());
 }
 
 // ASan allocator doesn't reserve extra bytes, so normally we would
@@ -1198,7 +1198,7 @@ uptr __sanitizer_get_allocated_size(const void *p) {
   return allocated_size;
 }
 
-void *__sanitizer_get_allocated_begin(const void *p) {
+const void *__sanitizer_get_allocated_begin(const void *p) {
   return AllocationBegin(p);
 }
 

compiler-rt/lib/dfsan/dfsan_allocator.cpp

@@ -174,7 +174,7 @@ void *DFsanCalloc(uptr nmemb, uptr size) {
   return DFsanAllocate(nmemb * size, sizeof(u64), true /*zeroise*/);
 }
 
-void *AllocationBegin(const void *p) {
+const void *AllocationBegin(const void *p) {
   if (!p)
     return nullptr;
   void *beg = allocator.GetBlockBegin(p);
@@ -185,7 +185,7 @@ void *AllocationBegin(const void *p) {
     return nullptr;
   if (b->requested_size == 0)
     return nullptr;
-  return (void *)beg;
+  return (const void *)beg;
 }
 
 static uptr AllocationSize(const void *p) {
@@ -308,7 +308,7 @@ uptr __sanitizer_get_estimated_allocated_size(uptr size) { return size; }
 
 int __sanitizer_get_ownership(const void *p) { return AllocationSize(p) != 0; }
 
-void *__sanitizer_get_allocated_begin(const void *p) {
+const void *__sanitizer_get_allocated_begin(const void *p) {
   return AllocationBegin(p);
 }
 

compiler-rt/lib/hwasan/hwasan_allocator.cpp

@@ -397,7 +397,7 @@ HwasanChunkView FindHeapChunkByAddress(uptr address) {
   return HwasanChunkView(reinterpret_cast<uptr>(block), metadata);
 }
 
-void *AllocationBegin(const void *p) {
+const void *AllocationBegin(const void *p) {
   const void *untagged_ptr = UntagPtr(p);
   if (!untagged_ptr)
     return nullptr;
@@ -411,7 +411,7 @@ void *AllocationBegin(const void *p) {
     return nullptr;
 
   tag_t tag = GetTagFromPointer((uptr)p);
-  return (void *)AddTagToPointer((uptr)beg, tag);
+  return (const void *)AddTagToPointer((uptr)beg, tag);
 }
 
 static uptr AllocationSize(const void *tagged_ptr) {
@@ -658,7 +658,7 @@ uptr __sanitizer_get_estimated_allocated_size(uptr size) { return size; }
 
 int __sanitizer_get_ownership(const void *p) { return AllocationSize(p) != 0; }
 
-void *__sanitizer_get_allocated_begin(const void *p) {
+const void *__sanitizer_get_allocated_begin(const void *p) {
   return AllocationBegin(p);
 }
 

compiler-rt/lib/lsan/lsan_allocator.cpp

@@ -145,7 +145,7 @@ void GetAllocatorCacheRange(uptr *begin, uptr *end) {
   *end = *begin + sizeof(AllocatorCache);
 }
 
-void *GetMallocBegin(const void *p) {
+const void *GetMallocBegin(const void *p) {
   if (!p)
     return nullptr;
   void *beg = allocator.GetBlockBegin(p);
@@ -158,7 +158,7 @@ void *GetMallocBegin(const void *p) {
     return nullptr;
   if (m->requested_size == 0)
     return nullptr;
-  return (void *)beg;
+  return (const void *)beg;
 }
 
 uptr GetMallocUsableSize(const void *p) {
@@ -380,7 +380,7 @@ SANITIZER_INTERFACE_ATTRIBUTE
 int __sanitizer_get_ownership(const void *p) { return Metadata(p) != nullptr; }
 
 SANITIZER_INTERFACE_ATTRIBUTE
-void * __sanitizer_get_allocated_begin(const void *p) {
+const void * __sanitizer_get_allocated_begin(const void *p) {
   return GetMallocBegin(p);
 }
 

compiler-rt/lib/memprof/memprof_allocator.cpp

@@ -681,7 +681,7 @@ int memprof_posix_memalign(void **memptr, uptr alignment, uptr size,
   return 0;
 }
 
-void *memprof_malloc_begin(const void *p) {
+const void *memprof_malloc_begin(const void *p) {
   u64 user_requested_size;
   MemprofChunk *m =
       instance.GetMemprofChunkByAddr((uptr)p, user_requested_size);
@@ -690,7 +690,7 @@ void *memprof_malloc_begin(const void *p) {
   if (user_requested_size == 0)
     return nullptr;
 
-  return (void *)m->Beg();
+  return (const void *)m->Beg();
 }
 
 uptr memprof_malloc_usable_size(const void *ptr, uptr pc, uptr bp) {
@@ -711,7 +711,7 @@ int __sanitizer_get_ownership(const void *p) {
   return memprof_malloc_usable_size(p, 0, 0) != 0;
 }
 
-void *__sanitizer_get_allocated_begin(const void *p) {
+const void *__sanitizer_get_allocated_begin(const void *p) {
   return memprof_malloc_begin(p);
 }
 

compiler-rt/lib/msan/msan_allocator.cpp

@@ -260,7 +260,7 @@ static void *MsanCalloc(StackTrace *stack, uptr nmemb, uptr size) {
   return MsanAllocate(stack, nmemb * size, sizeof(u64), true);
 }
 
-void *AllocationBegin(const void *p) {
+const void *AllocationBegin(const void *p) {
   if (!p)
     return nullptr;
   void *beg = allocator.GetBlockBegin(p);
@@ -272,7 +272,7 @@ void *AllocationBegin(const void *p) {
   if (b->requested_size == 0)
     return nullptr;
 
-  return (void *)beg;
+  return (const void *)beg;
 }
 
 static uptr AllocationSize(const void *p) {
@@ -388,7 +388,7 @@ uptr __sanitizer_get_estimated_allocated_size(uptr size) { return size; }
 
 int __sanitizer_get_ownership(const void *p) { return AllocationSize(p) != 0; }
 
-void *__sanitizer_get_allocated_begin(const void *p) {
+const void *__sanitizer_get_allocated_begin(const void *p) {
   return AllocationBegin(p);
 }
 

compiler-rt/lib/sanitizer_common/sanitizer_allocator_interface.h

@@ -21,7 +21,7 @@ extern "C" {
 SANITIZER_INTERFACE_ATTRIBUTE
 uptr __sanitizer_get_estimated_allocated_size(uptr size);
 SANITIZER_INTERFACE_ATTRIBUTE int __sanitizer_get_ownership(const void *p);
-SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE void *
+SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE const void *
 __sanitizer_get_allocated_begin(const void *p);
 SANITIZER_INTERFACE_ATTRIBUTE uptr
 __sanitizer_get_allocated_size(const void *p);

compiler-rt/lib/tsan/rtl/tsan_mman.cpp

@@ -352,7 +352,7 @@ void *user_pvalloc(ThreadState *thr, uptr pc, uptr sz) {
   return SetErrnoOnNull(user_alloc_internal(thr, pc, sz, PageSize));
 }
 
-void *user_alloc_begin(const void *p) {
+const void *user_alloc_begin(const void *p) {
   if (p == nullptr || !IsAppMem((uptr)p))
     return nullptr;
   void *beg = allocator()->GetBlockBegin(p);
@@ -363,7 +363,7 @@ void *user_alloc_begin(const void *p) {
   if (!b)
     return nullptr;  // Not a valid pointer.
 
-  return (void *)beg;
+  return (const void *)beg;
 }
 
 uptr user_alloc_usable_size(const void *p) {
@@ -444,7 +444,7 @@ int __sanitizer_get_ownership(const void *p) {
   return allocator()->GetBlockBegin(p) != 0;
 }
 
-void *__sanitizer_get_allocated_begin(const void *p) {
+const void *__sanitizer_get_allocated_begin(const void *p) {
   return user_alloc_begin(p);
 }
 

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

@@ -23,7 +23,7 @@ int main(void) {
 
     // Bogus value to unpoison start. Calling __sanitizer_get_allocated_begin
     // does not unpoison it.
-    void *start = NULL;
+    const void *start = NULL;
     for (int j = 0; j < sizes[i]; j++) {
       printf("j: %d\n", j);