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 COMPILER_RT_VISIBILITY 71 void __llvm_profile_get_padding_sizes_for_counters( 72 uint64_t DataSize, uint64_t CountersSize, uint64_t NamesSize, 73 uint64_t *PaddingBytesBeforeCounters, uint64_t *PaddingBytesAfterCounters, 74 uint64_t *PaddingBytesAfterNames) { 75 if (!__llvm_profile_is_continuous_mode_enabled() || 76 lprofRuntimeCounterRelocation()) { 77 *PaddingBytesBeforeCounters = 0; 78 *PaddingBytesAfterCounters = 0; 79 *PaddingBytesAfterNames = __llvm_profile_get_num_padding_bytes(NamesSize); 80 return; 81 } 82 83 // In continuous mode, the file offsets for headers and for the start of 84 // counter sections need to be page-aligned. 85 uint64_t DataSizeInBytes = DataSize * sizeof(__llvm_profile_data); 86 uint64_t CountersSizeInBytes = CountersSize * sizeof(uint64_t); 87 *PaddingBytesBeforeCounters = calculateBytesNeededToPageAlign( 88 sizeof(__llvm_profile_header) + DataSizeInBytes); 89 *PaddingBytesAfterCounters = 90 calculateBytesNeededToPageAlign(CountersSizeInBytes); 91 *PaddingBytesAfterNames = calculateBytesNeededToPageAlign(NamesSize); 92 } 93 94 COMPILER_RT_VISIBILITY 95 uint64_t __llvm_profile_get_size_for_buffer_internal( 96 const __llvm_profile_data *DataBegin, const __llvm_profile_data *DataEnd, 97 const uint64_t *CountersBegin, const uint64_t *CountersEnd, 98 const char *NamesBegin, const char *NamesEnd) { 99 /* Match logic in __llvm_profile_write_buffer(). */ 100 const uint64_t NamesSize = (NamesEnd - NamesBegin) * sizeof(char); 101 uint64_t DataSize = __llvm_profile_get_data_size(DataBegin, DataEnd); 102 uint64_t CountersSize = CountersEnd - CountersBegin; 103 104 /* Determine how much padding is needed before/after the counters and after 105 * the names. */ 106 uint64_t PaddingBytesBeforeCounters, PaddingBytesAfterCounters, 107 PaddingBytesAfterNames; 108 __llvm_profile_get_padding_sizes_for_counters( 109 DataSize, CountersSize, NamesSize, &PaddingBytesBeforeCounters, 110 &PaddingBytesAfterCounters, &PaddingBytesAfterNames); 111 112 return sizeof(__llvm_profile_header) + 113 (DataSize * sizeof(__llvm_profile_data)) + PaddingBytesBeforeCounters + 114 (CountersSize * sizeof(uint64_t)) + PaddingBytesAfterCounters + 115 NamesSize + PaddingBytesAfterNames; 116 } 117 118 COMPILER_RT_VISIBILITY 119 void initBufferWriter(ProfDataWriter *BufferWriter, char *Buffer) { 120 BufferWriter->Write = lprofBufferWriter; 121 BufferWriter->WriterCtx = Buffer; 122 } 123 124 COMPILER_RT_VISIBILITY int __llvm_profile_write_buffer(char *Buffer) { 125 ProfDataWriter BufferWriter; 126 initBufferWriter(&BufferWriter, Buffer); 127 return lprofWriteData(&BufferWriter, 0, 0); 128 } 129 130 COMPILER_RT_VISIBILITY int __llvm_profile_write_buffer_internal( 131 char *Buffer, const __llvm_profile_data *DataBegin, 132 const __llvm_profile_data *DataEnd, const uint64_t *CountersBegin, 133 const uint64_t *CountersEnd, const char *NamesBegin, const char *NamesEnd) { 134 ProfDataWriter BufferWriter; 135 initBufferWriter(&BufferWriter, Buffer); 136 return lprofWriteDataImpl(&BufferWriter, DataBegin, DataEnd, CountersBegin, 137 CountersEnd, 0, NamesBegin, NamesEnd, 0); 138 } 139