1 /*===- InstrProfilingPlatformFuchsia.c - Profile data Fuchsia platform ----===*\ 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 * This file implements the profiling runtime for Fuchsia and defines the 10 * shared profile runtime interface. Each module (executable or DSO) statically 11 * links in the whole profile runtime to satisfy the calls from its 12 * instrumented code. Several modules in the same program might be separately 13 * compiled and even use different versions of the instrumentation ABI and data 14 * format. All they share in common is the VMO and the offset, which live in 15 * exported globals so that exactly one definition will be shared across all 16 * modules. Each module has its own independent runtime that registers its own 17 * atexit hook to append its own data into the shared VMO which is published 18 * via the data sink hook provided by Fuchsia's dynamic linker. 19 */ 20 21 #if defined(__Fuchsia__) 22 23 #include <inttypes.h> 24 #include <stdarg.h> 25 #include <stdbool.h> 26 #include <stdlib.h> 27 28 #include <zircon/process.h> 29 #include <zircon/sanitizer.h> 30 #include <zircon/status.h> 31 #include <zircon/syscalls.h> 32 33 #include "InstrProfiling.h" 34 #include "InstrProfilingInternal.h" 35 #include "InstrProfilingUtil.h" 36 37 /* This variable is an external reference to symbol defined by the compiler. */ 38 COMPILER_RT_VISIBILITY extern intptr_t INSTR_PROF_PROFILE_COUNTER_BIAS_VAR; 39 40 COMPILER_RT_VISIBILITY unsigned lprofProfileDumped() { 41 return 1; 42 } 43 COMPILER_RT_VISIBILITY void lprofSetProfileDumped(unsigned Value) {} 44 45 static const char ProfileSinkName[] = "llvm-profile"; 46 47 static inline void lprofWrite(const char *fmt, ...) { 48 char s[256]; 49 50 va_list ap; 51 va_start(ap, fmt); 52 int ret = vsnprintf(s, sizeof(s), fmt, ap); 53 va_end(ap); 54 55 __sanitizer_log_write(s, ret); 56 } 57 58 struct lprofVMOWriterCtx { 59 /* VMO that contains the profile data for this module. */ 60 zx_handle_t Vmo; 61 /* Current offset within the VMO where data should be written next. */ 62 uint64_t Offset; 63 }; 64 65 static uint32_t lprofVMOWriter(ProfDataWriter *This, ProfDataIOVec *IOVecs, 66 uint32_t NumIOVecs) { 67 struct lprofVMOWriterCtx *Ctx = (struct lprofVMOWriterCtx *)This->WriterCtx; 68 69 /* Compute the total length of data to be written. */ 70 size_t Length = 0; 71 for (uint32_t I = 0; I < NumIOVecs; I++) 72 Length += IOVecs[I].ElmSize * IOVecs[I].NumElm; 73 74 /* Resize the VMO to ensure there's sufficient space for the data. */ 75 zx_status_t Status = _zx_vmo_set_size(Ctx->Vmo, Ctx->Offset + Length); 76 if (Status != ZX_OK) 77 return -1; 78 79 /* Copy the data into VMO. */ 80 for (uint32_t I = 0; I < NumIOVecs; I++) { 81 size_t Length = IOVecs[I].ElmSize * IOVecs[I].NumElm; 82 if (IOVecs[I].Data) { 83 Status = _zx_vmo_write(Ctx->Vmo, IOVecs[I].Data, Ctx->Offset, Length); 84 if (Status != ZX_OK) 85 return -1; 86 } else if (IOVecs[I].UseZeroPadding) { 87 /* Resizing the VMO should zero fill. */ 88 } 89 Ctx->Offset += Length; 90 } 91 92 /* Record the profile size as a property of the VMO. */ 93 _zx_object_set_property(Ctx->Vmo, ZX_PROP_VMO_CONTENT_SIZE, &Ctx->Offset, 94 sizeof(Ctx->Offset)); 95 96 return 0; 97 } 98 99 static void initVMOWriter(ProfDataWriter *This, struct lprofVMOWriterCtx *Ctx) { 100 This->Write = lprofVMOWriter; 101 This->WriterCtx = Ctx; 102 } 103 104 /* This method is invoked by the runtime initialization hook 105 * InstrProfilingRuntime.o if it is linked in. */ 106 COMPILER_RT_VISIBILITY 107 void __llvm_profile_initialize(void) { 108 /* Check if there is llvm/runtime version mismatch. */ 109 if (GET_VERSION(__llvm_profile_get_version()) != INSTR_PROF_RAW_VERSION) { 110 lprofWrite("LLVM Profile: runtime and instrumentation version mismatch: " 111 "expected %d, but got %d\n", 112 INSTR_PROF_RAW_VERSION, 113 (int)GET_VERSION(__llvm_profile_get_version())); 114 return; 115 } 116 117 const __llvm_profile_data *DataBegin = __llvm_profile_begin_data(); 118 const __llvm_profile_data *DataEnd = __llvm_profile_end_data(); 119 const char *CountersBegin = __llvm_profile_begin_counters(); 120 const char *CountersEnd = __llvm_profile_end_counters(); 121 const uint64_t DataSize = __llvm_profile_get_data_size(DataBegin, DataEnd); 122 const uint64_t CountersOffset = 123 sizeof(__llvm_profile_header) + __llvm_write_binary_ids(NULL) + DataSize; 124 uint64_t CountersSize = 125 __llvm_profile_get_counters_size(CountersBegin, CountersEnd); 126 127 /* Don't publish a VMO if there are no counters. */ 128 if (!CountersSize) 129 return; 130 131 zx_status_t Status; 132 133 /* Create a VMO to hold the profile data. */ 134 zx_handle_t Vmo = ZX_HANDLE_INVALID; 135 Status = _zx_vmo_create(0, ZX_VMO_RESIZABLE, &Vmo); 136 if (Status != ZX_OK) { 137 lprofWrite("LLVM Profile: cannot create VMO: %s\n", 138 _zx_status_get_string(Status)); 139 return; 140 } 141 142 /* Give the VMO a name that includes the module signature. */ 143 char VmoName[ZX_MAX_NAME_LEN]; 144 snprintf(VmoName, sizeof(VmoName), "%" PRIu64 ".profraw", 145 lprofGetLoadModuleSignature()); 146 _zx_object_set_property(Vmo, ZX_PROP_NAME, VmoName, strlen(VmoName)); 147 148 /* Write the profile data into the mapped region. */ 149 ProfDataWriter VMOWriter; 150 struct lprofVMOWriterCtx Ctx = {.Vmo = Vmo, .Offset = 0}; 151 initVMOWriter(&VMOWriter, &Ctx); 152 if (lprofWriteData(&VMOWriter, 0, 0) != 0) { 153 lprofWrite("LLVM Profile: failed to write data\n"); 154 _zx_handle_close(Vmo); 155 return; 156 } 157 158 uint64_t Len = 0; 159 Status = _zx_vmo_get_size(Vmo, &Len); 160 if (Status != ZX_OK) { 161 lprofWrite("LLVM Profile: failed to get the VMO size: %s\n", 162 _zx_status_get_string(Status)); 163 _zx_handle_close(Vmo); 164 return; 165 } 166 167 uintptr_t Mapping; 168 Status = 169 _zx_vmar_map(_zx_vmar_root_self(), ZX_VM_PERM_READ | ZX_VM_PERM_WRITE, 0, 170 Vmo, 0, Len, &Mapping); 171 if (Status != ZX_OK) { 172 lprofWrite("LLVM Profile: failed to map the VMO: %s\n", 173 _zx_status_get_string(Status)); 174 _zx_handle_close(Vmo); 175 return; 176 } 177 178 /* Publish the VMO which contains profile data to the system. Note that this 179 * also consumes the VMO handle. */ 180 __sanitizer_publish_data(ProfileSinkName, Vmo); 181 182 /* Update the profile fields based on the current mapping. */ 183 INSTR_PROF_PROFILE_COUNTER_BIAS_VAR = 184 (intptr_t)Mapping - (uintptr_t)CountersBegin + CountersOffset; 185 186 /* Return the memory allocated for counters to OS. */ 187 lprofReleaseMemoryPagesToOS((uintptr_t)CountersBegin, (uintptr_t)CountersEnd); 188 } 189 190 #endif 191