From 65fc51bbe29d39a0aae860dc4f1f9e75a800e221 Mon Sep 17 00:00:00 2001 From: NAKAMURA Takumi Date: Wed, 4 Sep 2013 14:12:19 +0000 Subject: [PATCH] MemoryBuffer.cpp: Don't peek the next page if file is multiple of *physical* pagesize(4k) but is not multiple of AllocationGranularity(64k), when a null terminator is required, on cygwin and win32. For example, r189780's SparcISelLowering.cpp has the size 98304. It crashed clang to touch a null terminator on cygwin. FIXME: It's not good to hardcode 4096 here. dwPageSize shows 4096. llvm-svn: 189939 --- llvm/lib/Support/MemoryBuffer.cpp | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/llvm/lib/Support/MemoryBuffer.cpp b/llvm/lib/Support/MemoryBuffer.cpp index 1134f5bb53e9..e018ad4ecce3 100644 --- a/llvm/lib/Support/MemoryBuffer.cpp +++ b/llvm/lib/Support/MemoryBuffer.cpp @@ -302,6 +302,15 @@ static bool shouldUseMmap(int FD, if (End != FileSize) return false; +#if defined(_WIN32) || defined(__CYGWIN__) + // Don't peek the next page if file is multiple of *physical* pagesize(4k) + // but is not multiple of AllocationGranularity(64k), + // when a null terminator is required. + // FIXME: It's not good to hardcode 4096 here. dwPageSize shows 4096. + if ((FileSize & (4096 - 1)) == 0) + return false; +#endif + // Don't try to map files that are exactly a multiple of the system page size // if we need a null terminator. if ((FileSize & (PageSize -1)) == 0)