Mike Klein | 7ac2be2 | 2020-11-05 09:38:53 -0600 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2020 Google Inc. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license that can be |
| 5 | * found in the LICENSE file. |
| 6 | */ |
| 7 | |
| 8 | #include "src/core/SkMSAN.h" |
| 9 | #include "src/core/SkOpts.h" |
| 10 | |
| 11 | #if defined(__x86_64__) || defined(_M_X64) // memset16 and memset32 could work on 32-bit x86 too. |
| 12 | |
| 13 | static const char* note = "MSAN can't see that rep sto initializes memory."; |
| 14 | |
| 15 | #if defined(_MSC_VER) |
| 16 | #include <intrin.h> |
| 17 | static inline void repsto(uint16_t* dst, uint16_t v, size_t n) { |
| 18 | sk_msan_mark_initialized(dst,dst+n,note); |
| 19 | __stosw(dst, v, n); |
| 20 | } |
| 21 | static inline void repsto(uint32_t* dst, uint32_t v, size_t n) { |
| 22 | sk_msan_mark_initialized(dst,dst+n,note); |
| 23 | static_assert(sizeof(uint32_t) == sizeof(unsigned long)); |
| 24 | __stosd(reinterpret_cast<unsigned long*>(dst), v, n); |
| 25 | } |
| 26 | static inline void repsto(uint64_t* dst, uint64_t v, size_t n) { |
| 27 | sk_msan_mark_initialized(dst,dst+n,note); |
| 28 | __stosq(dst, v, n); |
| 29 | } |
| 30 | #else |
| 31 | static inline void repsto(uint16_t* dst, uint16_t v, size_t n) { |
| 32 | sk_msan_mark_initialized(dst,dst+n,note); |
| 33 | asm volatile("rep stosw" : "+D"(dst), "+c"(n) : "a"(v) : "memory"); |
| 34 | } |
| 35 | static inline void repsto(uint32_t* dst, uint32_t v, size_t n) { |
| 36 | sk_msan_mark_initialized(dst,dst+n,note); |
| 37 | asm volatile("rep stosl" : "+D"(dst), "+c"(n) : "a"(v) : "memory"); |
| 38 | } |
| 39 | static inline void repsto(uint64_t* dst, uint64_t v, size_t n) { |
| 40 | sk_msan_mark_initialized(dst,dst+n,note); |
| 41 | asm volatile("rep stosq" : "+D"(dst), "+c"(n) : "a"(v) : "memory"); |
| 42 | } |
| 43 | #endif |
| 44 | |
| 45 | // ERMS is ideal for large copies but has a relatively high setup cost, |
| 46 | // so we use the previous best routine for small inputs. FSRM would make this moot. |
| 47 | static void (*g_memset16_prev)(uint16_t*, uint16_t, int); |
| 48 | static void (*g_memset32_prev)(uint32_t*, uint32_t, int); |
| 49 | static void (*g_memset64_prev)(uint64_t*, uint64_t, int); |
| 50 | static void (*g_rect_memset16_prev)(uint16_t*, uint16_t, int, size_t, int); |
| 51 | static void (*g_rect_memset32_prev)(uint32_t*, uint32_t, int, size_t, int); |
| 52 | static void (*g_rect_memset64_prev)(uint64_t*, uint64_t, int, size_t, int); |
| 53 | |
| 54 | // Empirically determined with `nanobench -m memset`. |
| 55 | static bool small(size_t bytes) { return bytes < 1024; } |
| 56 | |
| 57 | #define SK_OPTS_NS erms |
| 58 | namespace SK_OPTS_NS { |
| 59 | static inline void memset16(uint16_t* dst, uint16_t v, int n) { |
| 60 | return small(sizeof(v)*n) ? g_memset16_prev(dst, v, n) |
| 61 | : repsto(dst, v, n); |
| 62 | } |
| 63 | static inline void memset32(uint32_t* dst, uint32_t v, int n) { |
| 64 | return small(sizeof(v)*n) ? g_memset32_prev(dst, v, n) |
| 65 | : repsto(dst, v, n); |
| 66 | } |
| 67 | static inline void memset64(uint64_t* dst, uint64_t v, int n) { |
| 68 | return small(sizeof(v)*n) ? g_memset64_prev(dst, v, n) |
| 69 | : repsto(dst, v, n); |
| 70 | } |
| 71 | |
| 72 | static inline void rect_memset16(uint16_t* dst, uint16_t v, int n, |
| 73 | size_t rowBytes, int height) { |
| 74 | if (small(sizeof(v)*n)) { |
| 75 | return g_rect_memset16_prev(dst,v,n, rowBytes,height); |
| 76 | } |
| 77 | for (int stride = rowBytes/sizeof(v); height --> 0; dst += stride) { |
| 78 | repsto(dst, v, n); |
| 79 | } |
| 80 | } |
| 81 | static inline void rect_memset32(uint32_t* dst, uint32_t v, int n, |
| 82 | size_t rowBytes, int height) { |
| 83 | if (small(sizeof(v)*n)) { |
| 84 | return g_rect_memset32_prev(dst,v,n, rowBytes,height); |
| 85 | } |
| 86 | for (int stride = rowBytes/sizeof(v); height --> 0; dst += stride) { |
| 87 | repsto(dst, v, n); |
| 88 | } |
| 89 | } |
| 90 | static inline void rect_memset64(uint64_t* dst, uint64_t v, int n, |
| 91 | size_t rowBytes, int height) { |
| 92 | if (small(sizeof(v)*n)) { |
| 93 | return g_rect_memset64_prev(dst,v,n, rowBytes,height); |
| 94 | } |
| 95 | for (int stride = rowBytes/sizeof(v); height --> 0; dst += stride) { |
| 96 | repsto(dst, v, n); |
| 97 | } |
| 98 | } |
| 99 | } // namespace SK_OPTS_NS |
| 100 | |
| 101 | namespace SkOpts { |
| 102 | void Init_erms() { |
| 103 | g_memset16_prev = memset16; |
| 104 | g_memset32_prev = memset32; |
| 105 | g_memset64_prev = memset64; |
| 106 | g_rect_memset16_prev = rect_memset16; |
| 107 | g_rect_memset32_prev = rect_memset32; |
| 108 | g_rect_memset64_prev = rect_memset64; |
| 109 | |
| 110 | memset16 = SK_OPTS_NS::memset16; |
| 111 | memset32 = SK_OPTS_NS::memset32; |
| 112 | memset64 = SK_OPTS_NS::memset64; |
| 113 | rect_memset16 = SK_OPTS_NS::rect_memset16; |
| 114 | rect_memset32 = SK_OPTS_NS::rect_memset32; |
| 115 | rect_memset64 = SK_OPTS_NS::rect_memset64; |
| 116 | } |
| 117 | } |
| 118 | #else |
| 119 | namespace SkOpts { |
| 120 | void Init_erms() {} |
| 121 | } |
| 122 | #endif |