Add support for zero length files
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13866 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/FileUtilities.cpp b/lib/Support/FileUtilities.cpp
index 74df8b2..ed594db 100644
--- a/lib/Support/FileUtilities.cpp
+++ b/lib/Support/FileUtilities.cpp
@@ -230,11 +230,17 @@
FDHandle FD(open(Filename.c_str(), O_RDONLY));
if (FD == -1) return 0;
+ // If the file has a length of zero, mmap might return a null pointer. In
+ // this case, allocate a single byte of memory and return it instead.
+ if (Length == 0)
+ return malloc(1);
+
// mmap in the file all at once...
void *Buffer = (void*)mmap(0, Length, PROT_READ, MAP_PRIVATE, FD, 0);
if (Buffer == (void*)MAP_FAILED)
return 0;
+
return Buffer;
#else
// FIXME: implement with read/write
@@ -246,7 +252,10 @@
/// address space.
void llvm::UnmapFileFromAddressSpace(void *Buffer, unsigned Length) {
#ifdef HAVE_MMAP_FILE
- munmap((char*)Buffer, Length);
+ if (Length)
+ munmap((char*)Buffer, Length);
+ else
+ free(Buffer); // Zero byte files are malloc(1)'s.
#else
free(Buffer);
#endif