1 files changed, 3 insertions, 2 deletions
diff --git a/llvm/lib/Support/Unix/Memory.inc b/llvm/lib/Support/Unix/Memory.inc
index 7bffdf38773..d70319168b8 100644
--- a/llvm/lib/Support/Unix/Memory.inc
+++ b/llvm/lib/Support/Unix/Memory.inc
@@ -152,6 +152,7 @@ Memory::releaseMappedMemory(MemoryBlock &M) {
 
 std::error_code
 Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) {
+  static const size_t PageSize = Process::getPageSize();
   if (M.Address == nullptr || M.Size == 0)
     return std::error_code();
 
@@ -160,7 +161,7 @@ Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) {
 
   int Protect = getPosixProtectionFlags(Flags);
 
-  int Result = ::mprotect(M.Address, M.Size, Protect);
+  int Result = ::mprotect((void*)((uintptr_t)M.Address & ~(PageSize-1)), PageSize*((M.Size+PageSize-1)/PageSize), Protect);
   if (Result != 0)
     return std::error_code(errno, std::generic_category());
 
@@ -180,7 +181,7 @@ Memory::AllocateRWX(size_t NumBytes, const MemoryBlock* NearBlock,
                     std::string *ErrMsg) {
   if (NumBytes == 0) return MemoryBlock();
 
-  size_t PageSize = Process::getPageSize();
+  static const size_t PageSize = Process::getPageSize();
   size_t NumPages = (NumBytes+PageSize-1)/PageSize;
 
   int fd = -1;