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1// Test whether mmap'ing profile counters onto an open file is feasible. As2// this involves some platform-specific logic, this test is designed to be a3// minimum viable proof-of-concept: it may be useful when porting the mmap()4// mode to a new platform, but is not in and of itself a test of the profiling5// runtime.6 7// REQUIRES: darwin, target={{arm64.*}}8 9// Align counters and data to the maximum expected page size (16K).10// RUN: %clang -g -o %t %s \11// RUN: -Wl,-sectalign,__DATA,__pcnts,0x4000 \12// RUN: -Wl,-sectalign,__DATA,__pdata,0x400013 14// Create a 'profile' using mmap() and validate it.15// RUN: %run %t create %t.tmpfile16// RUN: %run %t validate %t.tmpfile17 18#include <fcntl.h>19#include <unistd.h>20#include <sys/mman.h>21#include <stdlib.h>22#include <stdio.h>23#include <string.h>24 25__attribute__((section("__DATA,__pcnts"))) int counters[] = {0xbad};26extern int cnts_start __asm("section$start$__DATA$__pcnts");27const size_t cnts_len = 0x4000;28 29__attribute__((section("__DATA,__pdata"))) int data[] = {1, 2, 3};30extern int data_start __asm("section$start$__DATA$__pdata");31const size_t data_len = sizeof(int) * 3;32 33int create_tmpfile(char *path) {34 // Create a temp file.35 int fd = open(path, O_RDWR | O_TRUNC | O_CREAT, 0666);36 if (fd == -1) {37 perror("open");38 return EXIT_FAILURE;39 }40 41 // Grow the file to hold data and counters.42 if (0 != ftruncate(fd, cnts_len + data_len)) {43 perror("ftruncate");44 return EXIT_FAILURE;45 }46 47 // Write the data first (at offset 0x1000, after the counters).48 if (data_len != pwrite(fd, &data, data_len, cnts_len)) {49 perror("write");50 return EXIT_FAILURE;51 }52 53 // Map the counters into the file, before the data.54 //55 // Requirements (on Darwin):56 // - &cnts_start must be page-aligned.57 // - The length and offset-into-fd must be page-aligned.58 int *counter_map = (int *)mmap(&cnts_start, cnts_len, PROT_READ | PROT_WRITE,59 MAP_FIXED | MAP_SHARED, fd, 0);60 if (counter_map != &cnts_start) {61 perror("mmap");62 return EXIT_FAILURE;63 }64 65 // Update counters 1..9. These updates should be visible in the file.66 // Expect counter 0 (0xbad), which is not updated, to be zero in the file.67 for (int i = 1; i < 10; ++i)68 counter_map[i] = i;69 70 // Intentionally do not msync(), munmap(), or close().71 return EXIT_SUCCESS;72}73 74int validate_tmpfile(char *path) {75 int fd = open(path, O_RDONLY);76 if (fd == -1) {77 perror("open");78 return EXIT_FAILURE;79 }80 81 // Verify that the file length is: sizeof(counters) + sizeof(data).82 const size_t num_bytes = cnts_len + data_len;83 int buf[num_bytes];84 if (num_bytes != read(fd, &buf, num_bytes)) {85 perror("read");86 return EXIT_FAILURE;87 }88 89 // Verify the values of counters 1..9 (i.e. that the mmap() worked).90 for (int i = 0; i < 10; ++i) {91 if (buf[i] != i) {92 fprintf(stderr,93 "validate_tmpfile: Expected '%d' at pos=%d, but got '%d' instead.\n",94 i, i, buf[i]);95 return EXIT_FAILURE;96 }97 }98 99 // Verify that the rest of the counters (after counter 9) are 0.100 const int num_cnts = cnts_len / sizeof(int);101 for (int i = 10; i < num_cnts; ++i) {102 if (buf[i] != 0) {103 fprintf(stderr,104 "validate_tmpfile: Expected '%d' at pos=%d, but got '%d' instead.\n",105 0, i, buf[i]);106 return EXIT_FAILURE;107 }108 }109 110 // Verify that the data written after the counters is equal to the "data[]"111 // array (i.e. {1, 2, 3}).112 for (int i = num_cnts; i < num_cnts + 3; ++i) {113 if (buf[i] != (i - num_cnts + 1)) {114 fprintf(stderr,115 "validate_tmpfile: Expected '%d' at pos=%d, but got '%d' instead.\n",116 i - num_cnts + 1, i, buf[i]);117 return EXIT_FAILURE;118 }119 }120 121 // Intentionally do not close().122 return EXIT_SUCCESS;123}124 125int main(int argc, char **argv) {126 intptr_t cnts_start_int = (intptr_t)&cnts_start;127 intptr_t data_start_int = (intptr_t)&data_start;128 int pagesz = getpagesize();129 130 if (cnts_start_int % pagesz != 0) {131 fprintf(stderr, "__pcnts is not page-aligned: 0x%lx.\n", cnts_start_int);132 return EXIT_FAILURE;133 }134 if (data_start_int % 0x4000 != 0) {135 fprintf(stderr, "__pdata is not correctly aligned: 0x%lx.\n",136 data_start_int);137 return EXIT_FAILURE;138 }139 if (cnts_start_int + 0x4000 != data_start_int) {140 fprintf(stderr, "__pdata not ordered after __pcnts.\n");141 return EXIT_FAILURE;142 }143 144 char *action = argv[1];145 char *path = argv[2];146 if (0 == strcmp(action, "create"))147 return create_tmpfile(path);148 else if (0 == strcmp(action, "validate"))149 return validate_tmpfile(path);150 else151 return EXIT_FAILURE;152}153