Make the host endianness check an integer constant expression.

I will remove the isBigEndianHost function once I update clang.

The ifdef logic is designed to
* not use configure/cmake to avoid breaking -arch i686 -arch ppc.
* default to little endian
* be as small as possible

It looks like sys/endian.h is the preferred header on most modern BSD systems,
but it is better to change this in a followup patch as machine/endian.h is
available on FreeBSD, OpenBSD, NetBSD and OS X.

llvm-svn: 179527

2 files changed, 3 insertions, 3 deletions

diff --git a/llvm/lib/Support/DataExtractor.cpp b/llvm/lib/Support/DataExtractor.cpp
index 3d5cce05358..a564d211b1d 100644
--- a/llvm/lib/Support/DataExtractor.cpp
+++ b/llvm/lib/Support/DataExtractor.cpp
@@ -20,7 +20,7 @@ static T getU(uint32_t *offset_ptr, const DataExtractor *de,
   uint32_t offset = *offset_ptr;
   if (de->isValidOffsetForDataOfSize(offset, sizeof(val))) {
     std::memcpy(&val, &Data[offset], sizeof(val));
-    if (sys::isLittleEndianHost() != isLittleEndian)
+    if (sys::IsLittleEndianHost != isLittleEndian)
       val = sys::SwapByteOrder(val);
 
     // Advance the offset
diff --git a/llvm/lib/Support/FoldingSet.cpp b/llvm/lib/Support/FoldingSet.cpp
index 36e33b5aafa..145f12dc1e5 100644
--- a/llvm/lib/Support/FoldingSet.cpp
+++ b/llvm/lib/Support/FoldingSet.cpp
@@ -101,7 +101,7 @@ void FoldingSetNodeID::AddString(StringRef String) {
     // Otherwise do it the hard way.
     // To be compatible with above bulk transfer, we need to take endianness
     // into account.
-    if (sys::isBigEndianHost()) {
+    if (sys::IsBigEndianHost) {
       for (Pos += 4; Pos <= Size; Pos += 4) {
         unsigned V = ((unsigned char)String[Pos - 4] << 24) |
                      ((unsigned char)String[Pos - 3] << 16) |
@@ -110,7 +110,7 @@ void FoldingSetNodeID::AddString(StringRef String) {
         Bits.push_back(V);
       }
     } else {
-      assert(sys::isLittleEndianHost() && "Unexpected host endianness");
+      assert(sys::IsLittleEndianHost && "Unexpected host endianness");
       for (Pos += 4; Pos <= Size; Pos += 4) {
         unsigned V = ((unsigned char)String[Pos - 1] << 24) |
                      ((unsigned char)String[Pos - 2] << 16) |