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. */
38COMPILER_RT_VISIBILITY extern intptr_t INSTR_PROF_PROFILE_COUNTER_BIAS_VAR;
39
40COMPILER_RT_VISIBILITY unsigned lprofProfileDumped(void) {
41 return 1;
42}
43COMPILER_RT_VISIBILITY void lprofSetProfileDumped(unsigned Value) {}
44
45static const char ProfileSinkName[] = "llvm-profile";
46
47static 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
58struct 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
65static 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
99static 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. */
106COMPILER_RT_VISIBILITY
107void __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

source code of compiler-rt/lib/profile/InstrProfilingPlatformFuchsia.c