[sanitizer] Define MAP_NORESERVE to 0 and hide mremap for FreeBSD

Author: MaskRay

compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp

@@ -183,11 +183,13 @@ uptr internal_munmap(void *addr, uptr length) {
   return internal_syscall(SYSCALL(munmap), (uptr)addr, length);
 }
 
+#if SANITIZER_LINUX
 uptr internal_mremap(void *old_address, uptr old_size, uptr new_size, int flags,
                      void *new_address) {
   return internal_syscall(SYSCALL(mremap), (uptr)old_address, old_size,
                           new_size, flags, (uptr)new_address);
 }
+#endif
 
 int internal_mprotect(void *addr, uptr length, int prot) {
   return internal_syscall(SYSCALL(mprotect), (uptr)addr, length, prot);

compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp

@@ -49,6 +49,10 @@
 #include <osreldate.h>
 #include <sys/sysctl.h>
 #define pthread_getattr_np pthread_attr_get_np
+// The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
+// that, it was never implemented. So just define it to zero.
+#undef MAP_NORESERVE
+#define MAP_NORESERVE 0
 #endif
 
 #if SANITIZER_NETBSD
@@ -883,6 +887,7 @@ static uptr MremapCreateAlias(uptr base_addr, uptr alias_addr,
                          reinterpret_cast<void *>(alias_addr));
 #else
   CHECK(false && "mremap is not supported outside of Linux");
+  return 0;
 #endif
 }
 

compiler-rt/lib/sanitizer_common/sanitizer_posix.h

@@ -40,8 +40,10 @@ uptr internal_write(fd_t fd, const void *buf, uptr count);
 uptr internal_mmap(void *addr, uptr length, int prot, int flags,
                    int fd, u64 offset);
 uptr internal_munmap(void *addr, uptr length);
+#if SANITIZER_LINUX
 uptr internal_mremap(void *old_address, uptr old_size, uptr new_size, int flags,
                      void *new_address);
+#endif
 int internal_mprotect(void *addr, uptr length, int prot);
 int internal_madvise(uptr addr, uptr length, int advice);