Use the same constants as zlib to represent compression level.

This change allows users pass compression level that was not listed
in the enum. Also, I think using different values than zlib's
compression levels was just confusing.

Differential Revision: https://reviews.llvm.org/D50196

llvm-svn: 338939
diff --git a/llvm/lib/Support/Compression.cpp b/llvm/lib/Support/Compression.cpp
index 05bd7b5..2217740 100644
--- a/llvm/lib/Support/Compression.cpp
+++ b/llvm/lib/Support/Compression.cpp
@@ -29,16 +29,6 @@
   return make_error<StringError>(Err, inconvertibleErrorCode());
 }
 
-static int encodeZlibCompressionLevel(zlib::CompressionLevel Level) {
-  switch (Level) {
-    case zlib::NoCompression: return 0;
-    case zlib::BestSpeedCompression: return 1;
-    case zlib::DefaultCompression: return Z_DEFAULT_COMPRESSION;
-    case zlib::BestSizeCompression: return 9;
-  }
-  llvm_unreachable("Invalid zlib::CompressionLevel!");
-}
-
 static StringRef convertZlibCodeToString(int Code) {
   switch (Code) {
   case Z_MEM_ERROR:
@@ -58,14 +48,12 @@
 bool zlib::isAvailable() { return true; }
 
 Error zlib::compress(StringRef InputBuffer,
-                     SmallVectorImpl<char> &CompressedBuffer,
-                     CompressionLevel Level) {
+                     SmallVectorImpl<char> &CompressedBuffer, int Level) {
   unsigned long CompressedSize = ::compressBound(InputBuffer.size());
   CompressedBuffer.reserve(CompressedSize);
-  int CLevel = encodeZlibCompressionLevel(Level);
-  int Res = ::compress2((Bytef *)CompressedBuffer.data(), &CompressedSize,
-                        (const Bytef *)InputBuffer.data(), InputBuffer.size(),
-                        CLevel);
+  int Res =
+      ::compress2((Bytef *)CompressedBuffer.data(), &CompressedSize,
+                  (const Bytef *)InputBuffer.data(), InputBuffer.size(), Level);
   // Tell MemorySanitizer that zlib output buffer is fully initialized.
   // This avoids a false report when running LLVM with uninstrumented ZLib.
   __msan_unpoison(CompressedBuffer.data(), CompressedSize);
@@ -118,4 +106,3 @@
   llvm_unreachable("zlib::crc32 is unavailable");
 }
 #endif
-