[BOLT][Instrumentation][NFC] define and use mmap constants

[treapster]

Summary

Split from D153771 to simplify review

[treapster]

Add MAP_FAILED

[treapster]

bolt/runtime/instr.cpp

1554

Should i remove it from this diff or add it to all mmap calls?

[rafauler]

bolt/runtime/instr.cpp

1554

Why do you ask? I think it's fine

[treapster]

bolt/runtime/instr.cpp

1554

Because i'm not sure it can be called NFC with the check added, but if it is, then we may as well add it to other places

[rafauler]

bolt/runtime/instr.cpp

1554

It's fine to leave as NFC.

[treapster]

Add assertions to other 2 mmap calls

bolt/runtime/common.h

#define RESTORE_ALL                                                            \
   "pop %%rbp\n"                                                                \
   "pop %%rsi\n"                                                                \
   "pop %%rdi\n"                                                                \
   "pop %%rdx\n"                                                                \
   "pop %%rcx\n"                                                                \
   "pop %%rbx\n"                                                                \
   "pop %%rax\n"
 
+#define PROT_READ 0x1  /* Page can be read.  */
+#define PROT_WRITE 0x2 /* Page can be written.  */
+#define PROT_EXEC 0x4  /* Page can be executed.  */
+#define PROT_NONE 0x0  /* Page can not be accessed.  */
+#define PROT_GROWSDOWN                                                         \
+  0x01000000 /* Extend change to start of                                      \
+                growsdown vma (mprotect only).  */
+#define PROT_GROWSUP                                                           \
+  0x02000000 /* Extend change to start of                                      \
+                growsup vma (mprotect only).  */
+
+/* Sharing types (must choose one and only one of these).  */
+#define MAP_SHARED 0x01  /* Share changes.  */
+#define MAP_PRIVATE 0x02 /* Changes are private.  */
+#define MAP_FIXED 0x10   /* Interpret addr exactly.  */
+
+#if defined(__APPLE__)
+#define MAP_ANONYMOUS 0x1000
+#else
+#define MAP_ANONYMOUS 0x20
+#endif
+
+#define MAP_FAILED ((void *)-1)
+
 // 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

     uint64_t AllocSize;
   };
 
 public:
   void *allocate(size_t Size) {
     Lock L(M);
 
     if (StackBase == nullptr) {
-#if defined(__APPLE__)
-    int MAP_PRIVATE_MAP_ANONYMOUS = 0x1002;
-#else
-    int MAP_PRIVATE_MAP_ANONYMOUS = 0x22;
-#endif
       StackBase = reinterpret_cast<uint8_t *>(
-          __mmap(0, MaxSize, 0x3 /* PROT_READ | PROT_WRITE*/,
-                 Shared ? 0x21 /*MAP_SHARED | MAP_ANONYMOUS*/
-                        : MAP_PRIVATE_MAP_ANONYMOUS /* MAP_PRIVATE | MAP_ANONYMOUS*/,
-                 -1, 0));
+          __mmap(0, MaxSize, PROT_READ | PROT_WRITE,
+                 (Shared ? MAP_SHARED : MAP_PRIVATE) | MAP_ANONYMOUS, -1, 0));
       StackSize = 0;
     }
 
     Size = alignTo(Size + sizeof(EntryMetadata), 16);
     uint8_t *AllocAddress = StackBase + StackSize + sizeof(EntryMetadata);
     auto *M = reinterpret_cast<EntryMetadata *>(StackBase + StackSize);
     M->Magic = Magic;
     M->AllocSize = Size;

                        /*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*/);
   uint8_t *BinContents = reinterpret_cast<uint8_t *>(
-      __mmap(0, Size, 0x1 /* PROT_READ*/, 0x2 /* MAP_PRIVATE*/, FD, 0));
+      __mmap(0, Size, PROT_READ, MAP_PRIVATE, FD, 0));
   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 *>(
       BinContents + Hdr->e_shoff + Hdr->e_shstrndx * Hdr->e_shentsize);
 
   // Find .bolt.instr.tables with the data we need and set pointers to it

   const uint64_t CountersEnd = alignTo(
       reinterpret_cast<uint64_t>(&__bolt_instr_locations[__bolt_num_counters]),
       0x1000);
   DEBUG(reportNumber("replace mmap start: ", CountersStart, 16));
   DEBUG(reportNumber("replace mmap stop: ", CountersEnd, 16));
   assert (CountersEnd > CountersStart, "no counters");
   // Maps our counters to be shared instead of private, so we keep counting for
   // forked processes
-  __mmap(CountersStart, CountersEnd - CountersStart,
-         0x3 /*PROT_READ|PROT_WRITE*/,
-         0x31 /*MAP_ANONYMOUS | MAP_SHARED | MAP_FIXED*/, -1, 0);
-
+  void *Ret =
+      __mmap(CountersStart, CountersEnd - CountersStart, PROT_READ | PROT_WRITE,
+             MAP_ANONYMOUS | MAP_SHARED | MAP_FIXED, -1, 0);
+  assert(Ret != MAP_FAILED, "Failed to mmap counters!");
   __bolt_ind_call_counter_func_pointer = __bolt_instr_indirect_call;
   __bolt_ind_tailcall_counter_func_pointer = __bolt_instr_indirect_tailcall;
   // Conservatively reserve 100MiB shared pages
   GlobalAlloc.setMaxSize(0x6400000);
   GlobalAlloc.setShared(true);
   GlobalWriteProfileMutex = new (GlobalAlloc, 0) Mutex();
   if (__bolt_instr_num_ind_calls > 0)
     GlobalIndCallCounters =