[Support] Renamed member 'Size' to 'AllocatedSize' in MemoryBlock and OwningMemoryBlock.

Rename member 'Size' to 'AllocatedSize' in order to provide a hint that the
allocated size may be different than the requested size. Comments are added to
clarify this point.  Updated the InMemoryBuffer in FileOutputBuffer.cpp to track
the requested buffer size.

Patch by Machiel van Hooren. Thanks Machiel!

https://reviews.llvm.org/D61599

llvm-svn: 361195

1 files changed, 12 insertions, 10 deletions

diff --git a/llvm/lib/Support/Unix/Memory.inc b/llvm/lib/Support/Unix/Memory.inc
index 05c5ccbdb3d..3b003362959 100644
--- a/llvm/lib/Support/Unix/Memory.inc
+++ b/llvm/lib/Support/Unix/Memory.inc
@@ -117,13 +117,15 @@ Memory::allocateMappedMemory(size_t NumBytes,
 
   // Use any near hint and the page size to set a page-aligned starting address
   uintptr_t Start = NearBlock ? reinterpret_cast<uintptr_t>(NearBlock->base()) +
-                                      NearBlock->size() : 0;
+                                      NearBlock->allocatedSize() : 0;
   static const size_t PageSize = Process::getPageSizeEstimate();
+  const size_t NumPages = (NumBytes+PageSize-1)/PageSize;
+
   if (Start && Start % PageSize)
     Start += PageSize - Start % PageSize;
 
   // FIXME: Handle huge page requests (MF_HUGE_HINT).
-  void *Addr = ::mmap(reinterpret_cast<void *>(Start), NumBytes, Protect,
+  void *Addr = ::mmap(reinterpret_cast<void *>(Start), PageSize*NumPages, Protect,
                       MMFlags, fd, 0);
   if (Addr == MAP_FAILED) {
     if (NearBlock) { //Try again without a near hint
@@ -146,7 +148,7 @@ Memory::allocateMappedMemory(size_t NumBytes,
 
   MemoryBlock Result;
   Result.Address = Addr;
-  Result.Size = NumBytes;
+  Result.AllocatedSize = PageSize*NumPages;
   Result.Flags = PFlags;
 
   // Rely on protectMappedMemory to invalidate instruction cache.
@@ -161,14 +163,14 @@ Memory::allocateMappedMemory(size_t NumBytes,
 
 std::error_code
 Memory::releaseMappedMemory(MemoryBlock &M) {
-  if (M.Address == nullptr || M.Size == 0)
+  if (M.Address == nullptr || M.AllocatedSize == 0)
     return std::error_code();
 
-  if (0 != ::munmap(M.Address, M.Size))
+  if (0 != ::munmap(M.Address, M.AllocatedSize))
     return std::error_code(errno, std::generic_category());
 
   M.Address = nullptr;
-  M.Size = 0;
+  M.AllocatedSize = 0;
 
   return std::error_code();
 }
@@ -176,7 +178,7 @@ Memory::releaseMappedMemory(MemoryBlock &M) {
 std::error_code
 Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) {
   static const size_t PageSize = Process::getPageSizeEstimate();
-  if (M.Address == nullptr || M.Size == 0)
+  if (M.Address == nullptr || M.AllocatedSize == 0)
     return std::error_code();
 
   if (!Flags)
@@ -184,7 +186,7 @@ Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) {
 
   int Protect = getPosixProtectionFlags(Flags);
   uintptr_t Start = alignAddr((uint8_t *)M.Address - PageSize + 1, PageSize);
-  uintptr_t End = alignAddr((uint8_t *)M.Address + M.Size, PageSize);
+  uintptr_t End = alignAddr((uint8_t *)M.Address + M.AllocatedSize, PageSize);
 
   bool InvalidateCache = (Flags & MF_EXEC);
 
@@ -197,7 +199,7 @@ Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) {
     if (Result != 0)
       return std::error_code(errno, std::generic_category());
 
-    Memory::InvalidateInstructionCache(M.Address, M.Size);
+    Memory::InvalidateInstructionCache(M.Address, M.AllocatedSize);
     InvalidateCache = false;
   }
 #endif
@@ -208,7 +210,7 @@ Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) {
     return std::error_code(errno, std::generic_category());
 
   if (InvalidateCache)
-    Memory::InvalidateInstructionCache(M.Address, M.Size);
+    Memory::InvalidateInstructionCache(M.Address, M.AllocatedSize);
 
   return std::error_code();
 }