Index: base/allocator/allocator_shim.h |
diff --git a/base/allocator/allocator_shim.h b/base/allocator/allocator_shim.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..9af44ce08cb27f864be81a1f2a927755db483d04 |
--- /dev/null |
+++ b/base/allocator/allocator_shim.h |
@@ -0,0 +1,87 @@ |
+// Copyright 2016 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#ifndef BASE_ALLOCATOR_ALLOCATOR_SHIM_H_ |
+#define BASE_ALLOCATOR_ALLOCATOR_SHIM_H_ |
+ |
+#include <stddef.h> |
+ |
+#include "base/base_export.h" |
+ |
+namespace base { |
+namespace allocator { |
+ |
+// Allocator Shim API. Allows to to: |
+// - Configure the behavior of the allocator (what to do on OOM failures). |
+// - Install new hooks (AllocatorDispatch) in the allocator chain. |
+ |
+// When this shim layer is enabled, the route of an allocation is as-follows: |
+// |
+// [allocator_shim_override_*.h] Intercept malloc() / operator new calls: |
+// The override_* headers define the symbols required to intercept calls to |
+// malloc() and operator new (if not overridden by specific C++ classes). |
+// |
+// [allocator_shim.cc] Routing allocation calls to the shim: |
+// The headers above route the calls to the internal ShimMalloc(), ShimFree(), |
+// ShimCppNew() etc. methods defined in allocator_shim.cc. |
+// These methods will: (1) forward the allocation call to the front of the |
+// AllocatorDispatch chain. (2) perform security hardenings (e.g., might |
+// call std::new_handler on OOM failure). |
+// |
+// [allocator_shim_default_dispatch_to_*.cc] The AllocatorDispatch chain: |
+// It is a singly linked list where each element is a struct with function |
+// pointers (|malloc_function|, |free_function|, etc). Normally the chain |
+// consists of a single AllocatorDispatch element, herein called |
+// the "default dispatch", which is statically defined at build time and |
+// ultimately routes the calls to the actual allocator defined by the build |
+// config (tcmalloc, glibc, ...). |
+// |
+// It is possible to dynamically insert further AllocatorDispatch stages |
+// to the front of the chain, for debugging / profiling purposes. |
+ |
+struct AllocatorDispatch { |
+ using AllocFn = void*(size_t size, const AllocatorDispatch* self); |
Nico
2016/03/08 03:08:42
why make self the last arg?
mention that these fu
Primiano Tucci (use gerrit)
2016/03/08 20:54:05
Is the question:
Q1) why having |self| at all?
Q2)
Nico
2016/03/09 05:34:25
Q3 – seems a bit more common (languages with expli
Primiano Tucci (use gerrit)
2016/03/09 10:51:59
Alright, point taken. Moved as 1st argument.
|
+ using AllocZeroInitializedFn = void*(size_t n, |
+ size_t size, |
+ const AllocatorDispatch* self); |
+ using AllocAlignedFn = void*(size_t alignment, |
+ size_t size, |
+ const AllocatorDispatch* self); |
+ using ReallocFn = void*(void* address, |
+ size_t size, |
+ const AllocatorDispatch* self); |
+ using FreeFn = void(void* address, const AllocatorDispatch* self); |
+ |
+ AllocFn* const alloc_function; |
+ AllocZeroInitializedFn* const alloc_zero_initialized_function; |
+ AllocAlignedFn* const alloc_aligned_function; |
+ ReallocFn* const realloc_function; |
+ FreeFn* const free_function; |
+ |
+ const AllocatorDispatch* next; |
+ |
+ // |default_dispatch| is statically defined by one (and only one) of the |
+ // allocator_shim_default_dispatch_to_*.cc files, depending on the build |
+ // configuration. |
+ static const AllocatorDispatch default_dispatch; |
+}; |
+ |
+// When true makes malloc behave like new, w.r.t calling the new_handler if |
+// the allocation fails (see set_new_mode() in Windows). |
+BASE_EXPORT void SetCallNewHandlerOnMallocFailure(bool value); |
+ |
+// Allocates |size| bytes or returns nullptr. It does NOT call the new_handler, |
+// regardless of SetCallNewHandlerOnMallocFailure(). |
+BASE_EXPORT void* UncheckedAlloc(size_t size); |
+ |
+// Inserts |dispatch| in front of the allocator chain. This method is NOT |
+// thread-safe w.r.t concurrent invocations of InsertAllocatorDispatch(). |
+// The callers have the responsibility of linearizing the changes to the chain |
+// (or more likely call these always on the same thread). |
+BASE_EXPORT void InsertAllocatorDispatch(AllocatorDispatch* dispatch); |
Nico
2016/03/08 03:08:42
removing a dispatch object is not possible?
Primiano Tucci (use gerrit)
2016/03/08 20:54:05
I removed it after a discussion that with chrisha:
|
+ |
+} // namespace allocator |
+} // namespace base |
+ |
+#endif // BASE_ALLOCATOR_ALLOCATOR_SHIM_H_ |