From e736e0c2d52a29a3b88a29ab39b3a90a5a2443a0 Mon Sep 17 00:00:00 2001
From: herb <herb@google.com>
Date: Thu, 3 Nov 2016 07:34:15 -0700
Subject: Try to use only std::aligned_storage. This does not change the API.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2468243002
TBR=reed@google.com

Review-Url: https://codereview.chromium.org/2468243002
---
 include/core/SkPostConfig.h       |  9 ---------
 src/core/SkLinearBitmapPipeline.h | 17 +++++++----------
 src/core/SkSmallAllocator.h       | 12 +++++-------
 3 files changed, 12 insertions(+), 26 deletions(-)

diff --git a/include/core/SkPostConfig.h b/include/core/SkPostConfig.h
index 1b1cb3e751..c34397cde6 100644
--- a/include/core/SkPostConfig.h
+++ b/include/core/SkPostConfig.h
@@ -77,15 +77,6 @@
 #  endif
 #endif
 
-// As usual, there are two ways to increase alignment... the MSVC way and the everyone-else way.
-#ifndef SK_STRUCT_ALIGN
-    #ifdef _MSC_VER
-        #define SK_STRUCT_ALIGN(N) __declspec(align(N))
-    #else
-        #define SK_STRUCT_ALIGN(N) __attribute__((aligned(N)))
-    #endif
-#endif
-
 #if defined(_MSC_VER) && SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
     #define SK_VECTORCALL __vectorcall
 #elif defined(SK_CPU_ARM32) && defined(SK_ARM_HAS_NEON)
diff --git a/src/core/SkLinearBitmapPipeline.h b/src/core/SkLinearBitmapPipeline.h
index 91b573df5d..d9fa97522e 100644
--- a/src/core/SkLinearBitmapPipeline.h
+++ b/src/core/SkLinearBitmapPipeline.h
@@ -57,6 +57,9 @@ public:
     void shadeSpan4f(int x, int y, SkPM4f* dst, int count);
     void blitSpan(int32_t x, int32_t y, void* dst, int count);
 
+    template <size_t N>
+    using Storage = typename std::aligned_storage<N, 16>::type;
+
     template<typename Base, size_t kSize, typename Next = void>
     class Stage {
     public:
@@ -84,11 +87,8 @@ public:
 
     private:
         std::function<void (Next*, void*)> fStageCloner;
-        struct SK_STRUCT_ALIGN(16) Space {
-            char space[kSize];
-        };
-        bool fIsInitialized;
-        mutable Space fSpace;
+        mutable Storage<kSize>             fSpace;
+        bool                               fIsInitialized;
     };
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
@@ -116,11 +116,8 @@ public:
         Base& operator*() const { return *(this->get()); }
 
     private:
-        struct SK_STRUCT_ALIGN(16) Space {
-            char space[kSize];
-        };
-        mutable Space fSpace;
-        bool          fIsInitialized;
+        mutable Storage<kSize> fSpace;
+        bool                   fIsInitialized;
 
     };
 
diff --git a/src/core/SkSmallAllocator.h b/src/core/SkSmallAllocator.h
index 9095fa57fc..b39e359d52 100644
--- a/src/core/SkSmallAllocator.h
+++ b/src/core/SkSmallAllocator.h
@@ -93,7 +93,7 @@ public:
             // There is space in fStorage.
             rec->fStorageSize = storageRequired;
             rec->fHeapStorage = nullptr;
-            rec->fObj = static_cast<void*>(fStorage.fBytes + fStorageUsed);
+            rec->fObj = static_cast<void*>(bytes() + fStorageUsed);
             fStorageUsed += storageRequired;
         }
         rec->fKillProc = DestroyT<T>;
@@ -129,13 +129,11 @@ private:
         static_cast<T*>(ptr)->~T();
     }
 
-    struct SK_STRUCT_ALIGN(16) Storage {
-        // we add kMaxObjects * 15 to account for the worst-case slop, where each allocation wasted
-        // 15 bytes (due to forcing each to be 16-byte aligned)
-        char    fBytes[kTotalBytes + kMaxObjects * 15];
-    };
+    char* bytes() { return reinterpret_cast<char*>(&fStorage); }
+
+    using Storage = typename std::aligned_storage<kTotalBytes, 16>::type;
 
-    Storage     fStorage;
+    Storage     fStorage[kMaxObjects];
     // Number of bytes used so far.
     size_t      fStorageUsed;
     uint32_t    fNumObjects;
-- 
cgit v1.2.3