1 /*===- InstrProfilingBuffer.c - Write instrumentation to a memory buffer --===*\ 2 |* 3 |* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 |* See https://llvm.org/LICENSE.txt for license information. 5 |* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 |* 7 \*===----------------------------------------------------------------------===*/ 8 9 // Note: This is linked into the Darwin kernel, and must remain compatible 10 // with freestanding compilation. See `darwin_add_builtin_libraries`. 11 12 #include "InstrProfiling.h" 13 #include "InstrProfilingInternal.h" 14 #include "InstrProfilingPort.h" 15 16 /* When continuous mode is enabled (%c), this parameter is set to 1. 17 * 18 * This parameter is defined here in InstrProfilingBuffer.o, instead of in 19 * InstrProfilingFile.o, to sequester all libc-dependent code in 20 * InstrProfilingFile.o. The test `instrprof-without-libc` will break if this 21 * layering is violated. */ 22 static int ContinuouslySyncProfile = 0; 23 24 /* The system page size. Only valid when non-zero. If 0, the page size is 25 * unavailable. */ 26 static unsigned PageSize = 0; 27 28 COMPILER_RT_VISIBILITY int __llvm_profile_is_continuous_mode_enabled(void) { 29 return ContinuouslySyncProfile && PageSize; 30 } 31 32 COMPILER_RT_VISIBILITY void __llvm_profile_enable_continuous_mode(void) { 33 ContinuouslySyncProfile = 1; 34 } 35 36 COMPILER_RT_VISIBILITY void __llvm_profile_set_page_size(unsigned PS) { 37 PageSize = PS; 38 } 39 40 COMPILER_RT_VISIBILITY 41 uint64_t __llvm_profile_get_size_for_buffer(void) { 42 const __llvm_profile_data *DataBegin = __llvm_profile_begin_data(); 43 const __llvm_profile_data *DataEnd = __llvm_profile_end_data(); 44 const uint64_t *CountersBegin = __llvm_profile_begin_counters(); 45 const uint64_t *CountersEnd = __llvm_profile_end_counters(); 46 const char *NamesBegin = __llvm_profile_begin_names(); 47 const char *NamesEnd = __llvm_profile_end_names(); 48 49 return __llvm_profile_get_size_for_buffer_internal( 50 DataBegin, DataEnd, CountersBegin, CountersEnd, NamesBegin, NamesEnd); 51 } 52 53 COMPILER_RT_VISIBILITY 54 uint64_t __llvm_profile_get_data_size(const __llvm_profile_data *Begin, 55 const __llvm_profile_data *End) { 56 intptr_t BeginI = (intptr_t)Begin, EndI = (intptr_t)End; 57 return ((EndI + sizeof(__llvm_profile_data) - 1) - BeginI) / 58 sizeof(__llvm_profile_data); 59 } 60 61 /// Calculate the number of padding bytes needed to add to \p Offset in order 62 /// for (\p Offset + Padding) to be page-aligned. 63 static uint64_t calculateBytesNeededToPageAlign(uint64_t Offset) { 64 uint64_t OffsetModPage = Offset % PageSize; 65 if (OffsetModPage > 0) 66 return PageSize - OffsetModPage; 67 return 0; 68 } 69 70 static int needsCounterPadding(void) { 71 #if defined(__APPLE__) 72 return __llvm_profile_is_continuous_mode_enabled(); 73 #else 74 return 0; 75 #endif 76 } 77 78 COMPILER_RT_VISIBILITY 79 void __llvm_profile_get_padding_sizes_for_counters( 80 uint64_t DataSize, uint64_t CountersSize, uint64_t NamesSize, 81 uint64_t *PaddingBytesBeforeCounters, uint64_t *PaddingBytesAfterCounters, 82 uint64_t *PaddingBytesAfterNames) { 83 if (!needsCounterPadding()) { 84 *PaddingBytesBeforeCounters = 0; 85 *PaddingBytesAfterCounters = 0; 86 *PaddingBytesAfterNames = __llvm_profile_get_num_padding_bytes(NamesSize); 87 return; 88 } 89 90 // In continuous mode, the file offsets for headers and for the start of 91 // counter sections need to be page-aligned. 92 uint64_t DataSizeInBytes = DataSize * sizeof(__llvm_profile_data); 93 uint64_t CountersSizeInBytes = CountersSize * sizeof(uint64_t); 94 *PaddingBytesBeforeCounters = calculateBytesNeededToPageAlign( 95 sizeof(__llvm_profile_header) + DataSizeInBytes); 96 *PaddingBytesAfterCounters = 97 calculateBytesNeededToPageAlign(CountersSizeInBytes); 98 *PaddingBytesAfterNames = calculateBytesNeededToPageAlign(NamesSize); 99 } 100 101 COMPILER_RT_VISIBILITY 102 uint64_t __llvm_profile_get_size_for_buffer_internal( 103 const __llvm_profile_data *DataBegin, const __llvm_profile_data *DataEnd, 104 const uint64_t *CountersBegin, const uint64_t *CountersEnd, 105 const char *NamesBegin, const char *NamesEnd) { 106 /* Match logic in __llvm_profile_write_buffer(). */ 107 const uint64_t NamesSize = (NamesEnd - NamesBegin) * sizeof(char); 108 uint64_t DataSize = __llvm_profile_get_data_size(DataBegin, DataEnd); 109 uint64_t CountersSize = CountersEnd - CountersBegin; 110 111 /* Determine how much padding is needed before/after the counters and after 112 * the names. */ 113 uint64_t PaddingBytesBeforeCounters, PaddingBytesAfterCounters, 114 PaddingBytesAfterNames; 115 __llvm_profile_get_padding_sizes_for_counters( 116 DataSize, CountersSize, NamesSize, &PaddingBytesBeforeCounters, 117 &PaddingBytesAfterCounters, &PaddingBytesAfterNames); 118 119 return sizeof(__llvm_profile_header) + __llvm_write_binary_ids(NULL) + 120 (DataSize * sizeof(__llvm_profile_data)) + PaddingBytesBeforeCounters + 121 (CountersSize * sizeof(uint64_t)) + PaddingBytesAfterCounters + 122 NamesSize + PaddingBytesAfterNames; 123 } 124 125 COMPILER_RT_VISIBILITY 126 void initBufferWriter(ProfDataWriter *BufferWriter, char *Buffer) { 127 BufferWriter->Write = lprofBufferWriter; 128 BufferWriter->WriterCtx = Buffer; 129 } 130 131 COMPILER_RT_VISIBILITY int __llvm_profile_write_buffer(char *Buffer) { 132 ProfDataWriter BufferWriter; 133 initBufferWriter(&BufferWriter, Buffer); 134 return lprofWriteData(&BufferWriter, 0, 0); 135 } 136 137 COMPILER_RT_VISIBILITY int __llvm_profile_write_buffer_internal( 138 char *Buffer, const __llvm_profile_data *DataBegin, 139 const __llvm_profile_data *DataEnd, const uint64_t *CountersBegin, 140 const uint64_t *CountersEnd, const char *NamesBegin, const char *NamesEnd) { 141 ProfDataWriter BufferWriter; 142 initBufferWriter(&BufferWriter, Buffer); 143 return lprofWriteDataImpl(&BufferWriter, DataBegin, DataEnd, CountersBegin, 144 CountersEnd, 0, NamesBegin, NamesEnd, 0); 145 } 146