[lsan] Invoke hooks on realloc

Previously lsan would not invoke hooks on reallocations.
An accompanying regression test is included in sanitizer_common.

This change also moves hook calls to a location where subsequent
calls (via an external caller) to __sanitizer_get_allocated_size
via hooks will return a valid size.

This allows a faster version of __sanitizer_get_allocated_size
to be implemented, which can skip checks.

Test to ensure RunFreeHooks' call order will come with
__sanitizer_get_allocated_size_fast

Differential Revision: https://reviews.llvm.org/D151175

compiler-rt/lib/lsan/lsan_allocator.cpp

@@ -65,12 +65,14 @@ static void RegisterAllocation(const StackTrace &stack, void *p, uptr size) {
   m->stack_trace_id = StackDepotPut(stack);
   m->requested_size = size;
   atomic_store(reinterpret_cast<atomic_uint8_t *>(m), 1, memory_order_relaxed);
+  RunMallocHooks(p, size);
 }
 
 static void RegisterDeallocation(void *p) {
   if (!p) return;
   ChunkMetadata *m = Metadata(p);
   CHECK(m);
+  RunFreeHooks(p);
   atomic_store(reinterpret_cast<atomic_uint8_t *>(m), 0, memory_order_relaxed);
 }
 
@@ -104,7 +106,6 @@ void *Allocate(const StackTrace &stack, uptr size, uptr alignment,
   if (cleared && allocator.FromPrimary(p))
     memset(p, 0, size);
   RegisterAllocation(stack, p, size);
-  RunMallocHooks(p, size);
   return p;
 }
 
@@ -119,7 +120,6 @@ static void *Calloc(uptr nmemb, uptr size, const StackTrace &stack) {
 }
 
 void Deallocate(void *p) {
-  RunFreeHooks(p);
   RegisterDeallocation(p);
   allocator.Deallocate(GetAllocatorCache(), p);
 }

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

@@ -21,7 +21,7 @@ const volatile void *global_ptr;
 // Note: avoid calling functions that allocate memory in malloc/free
 // to avoid infinite recursion.
 void __sanitizer_malloc_hook(const volatile void *ptr, size_t sz) {
-  if (__sanitizer_get_ownership(ptr) && sz == 4) {
+  if (__sanitizer_get_ownership(ptr) && sz == sizeof(int)) {
     WRITE("MallocHook\n");
     global_ptr = ptr;
   }
@@ -42,7 +42,7 @@ void FreeHook2(const volatile void *ptr) { WRITE("FH2\n"); }
 // TLS shadow for function parameters before calling operator
 // new and, eventually, user-provided hook.
 __attribute__((noinline)) void allocate(int *unused1, int *unused2) {
-  x = new int;
+  x = reinterpret_cast<int *>(malloc(sizeof(int)));
 }
 
 int main() {
@@ -57,9 +57,17 @@ int main() {
   if (global_ptr != (void*)x) {
     _exit(1);
   }
-  *x = 0;
-  delete x;
-  // CHECK: FreeHook
+
+  // Check that realloc invokes hooks
+  // We realloc to 128 here to avoid potential oversizing by allocators
+  // making this a no-op.
+  x = reinterpret_cast<int *>(realloc((int *)x, sizeof(int) * 128));
+  // CHECK-DAG: FreeHook{{[[:space:]].*}}FH1{{[[:space:]].*}}FH2
+  // CHECK-DAG: MH1{{[[:space:]].*}}MH2
+
+  x[0] = 0;
+  x[127] = -1;
+  free((void *)x);
   // CHECK: FH1
   // CHECK: FH2
   return 0;