[BOLT][Instrumentation][NFC] Define and use more syscall constants

[treapster]

Summary

Follow-up to https://reviews.llvm.org/D154056

[treapster]

Fix values

bolt/runtime/common.h

 #if defined(__APPLE__)
 #define MAP_ANONYMOUS 0x1000
 #else
 #define MAP_ANONYMOUS 0x20
 #endif
 
 #define MAP_FAILED ((void *)-1)
 
+#define SEEK_SET 0 /* Seek from beginning of file.  */
+#define SEEK_CUR 1 /* Seek from current position.  */
+#define SEEK_END 2 /* Seek from end of file.  */
+
+#define O_RDONLY 0
+#define O_WRONLY 1
+#define O_RDWR 2
+#define O_CREAT 64
+#define O_TRUNC 512
+#define O_APPEND 1024
+
 // Functions that are required by freestanding environment. Compiler may
 // generate calls to these implicitly.
 extern "C" {
 void *memcpy(void *Dest, const void *Src, size_t Len) {
   uint8_t *d = static_cast<uint8_t *>(Dest);
   const uint8_t *s = static_cast<const uint8_t *>(Src);
   while (Len--)
     *d++ = *s++;

bolt/runtime/instr.cpp

static char *getBinaryPath() {
 
   if (__bolt_instr_binpath[0] != '\0')
     return __bolt_instr_binpath;
 
   if (TargetPath[0] != '\0')
     return TargetPath;
 
   unsigned long CurAddr = (unsigned long)__get_pc();
-  uint64_t FDdir = __open(DirPath,
-                          /*flags=*/0 /*O_RDONLY*/,
+  uint64_t FDdir = __open(DirPath, O_RDONLY,
                           /*mode=*/0666);
   assert(static_cast<int64_t>(FDdir) >= 0,
          "failed to open /proc/self/map_files");
 
   while (long Nread = __getdents(FDdir, (struct dirent *)Buf, BufSize)) {
     assert(static_cast<int64_t>(Nread) != -1, "failed to get folder entries");
 
     struct dirent *d;
static char *getBinaryPath() {
   return nullptr;
 }
 
 ProfileWriterContext readDescriptions() {
   ProfileWriterContext Result;
   char *BinPath = getBinaryPath();
   assert(BinPath && BinPath[0] != '\0', "failed to find binary path");
 
-  uint64_t FD = __open(BinPath,
-                       /*flags=*/0 /*O_RDONLY*/,
+  uint64_t FD = __open(BinPath, O_RDONLY,
                        /*mode=*/0666);
   assert(static_cast<int64_t>(FD) >= 0, "failed to open binary path");
 
   Result.FileDesc = FD;
 
   // mmap our binary to memory
-  uint64_t Size = __lseek(FD, 0, 2 /*SEEK_END*/);
+  uint64_t Size = __lseek(FD, 0, SEEK_END);
   uint8_t *BinContents = reinterpret_cast<uint8_t *>(
       __mmap(0, Size, PROT_READ, MAP_PRIVATE, FD, 0));
   assert(BinContents != MAP_FAILED, "readDescriptions: Failed to mmap self!");
   Result.MMapPtr = BinContents;
   Result.MMapSize = Size;
   Elf64_Ehdr *Hdr = reinterpret_cast<Elf64_Ehdr *>(BinContents);
   Elf64_Shdr *Shdr = reinterpret_cast<Elf64_Shdr *>(BinContents + Hdr->e_shoff);
   Elf64_Shdr *StringTblHeader = reinterpret_cast<Elf64_Shdr *>(
int openProfile() {
   uint64_t PID = __getpid();
   Ptr = strCopy(Buf, __bolt_instr_filename, BufSize);
   if (__bolt_instr_use_pid) {
     Ptr = strCopy(Ptr, ".", BufSize - (Ptr - Buf + 1));
     Ptr = intToStr(Ptr, PID, 10);
     Ptr = strCopy(Ptr, ".fdata", BufSize - (Ptr - Buf + 1));
   }
   *Ptr++ = '\0';
-  uint64_t FD = __open(Buf,
-                       /*flags=*/0x241 /*O_WRONLY|O_TRUNC|O_CREAT*/,
+  uint64_t FD = __open(Buf, O_WRONLY | O_TRUNC | O_CREAT,
                        /*mode=*/0666);
   if (static_cast<int64_t>(FD) < 0) {
     report("Error while trying to open profile file for writing: ");
     report(Buf);
     reportNumber("\nFailed with error number: 0x",
                  0 - static_cast<int64_t>(FD), 16);
     __exit(1);
   }