1 files changed, 106 insertions, 0 deletions
diff --git a/llvm/lib/Support/Compression.cpp b/llvm/lib/Support/Compression.cpp
new file mode 100644
index 0000000000000..97d5ffaadf827
--- /dev/null
+++ b/llvm/lib/Support/Compression.cpp
@@ -0,0 +1,106 @@
+//===--- Compression.cpp - Compression implementation ---------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements compression functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Compression.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/ErrorHandling.h"
+#if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
+#include <zlib.h>
+#endif
+
+using namespace llvm;
+
+#if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
+static Error createError(StringRef Err) {
+  return make_error<StringError>(Err, inconvertibleErrorCode());
+}
+
+static StringRef convertZlibCodeToString(int Code) {
+  switch (Code) {
+  case Z_MEM_ERROR:
+    return "zlib error: Z_MEM_ERROR";
+  case Z_BUF_ERROR:
+    return "zlib error: Z_BUF_ERROR";
+  case Z_STREAM_ERROR:
+    return "zlib error: Z_STREAM_ERROR";
+  case Z_DATA_ERROR:
+    return "zlib error: Z_DATA_ERROR";
+  case Z_OK:
+  default:
+    llvm_unreachable("unknown or unexpected zlib status code");
+  }
+}
+
+bool zlib::isAvailable() { return true; }
+
+Error zlib::compress(StringRef InputBuffer,
+                     SmallVectorImpl<char> &CompressedBuffer, int Level) {
+  unsigned long CompressedSize = ::compressBound(InputBuffer.size());
+  CompressedBuffer.reserve(CompressedSize);
+  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);
+  CompressedBuffer.set_size(CompressedSize);
+  return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
+}
+
+Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
+                       size_t &UncompressedSize) {
+  int Res =
+      ::uncompress((Bytef *)UncompressedBuffer, (uLongf *)&UncompressedSize,
+                   (const Bytef *)InputBuffer.data(), InputBuffer.size());
+  // Tell MemorySanitizer that zlib output buffer is fully initialized.
+  // This avoids a false report when running LLVM with uninstrumented ZLib.
+  __msan_unpoison(UncompressedBuffer, UncompressedSize);
+  return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
+}
+
+Error zlib::uncompress(StringRef InputBuffer,
+                       SmallVectorImpl<char> &UncompressedBuffer,
+                       size_t UncompressedSize) {
+  UncompressedBuffer.resize(UncompressedSize);
+  Error E =
+      uncompress(InputBuffer, UncompressedBuffer.data(), UncompressedSize);
+  UncompressedBuffer.resize(UncompressedSize);
+  return E;
+}
+
+uint32_t zlib::crc32(StringRef Buffer) {
+  return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
+}
+
+#else
+bool zlib::isAvailable() { return false; }
+Error zlib::compress(StringRef InputBuffer,
+                     SmallVectorImpl<char> &CompressedBuffer, int Level) {
+  llvm_unreachable("zlib::compress is unavailable");
+}
+Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
+                       size_t &UncompressedSize) {
+  llvm_unreachable("zlib::uncompress is unavailable");
+}
+Error zlib::uncompress(StringRef InputBuffer,
+                       SmallVectorImpl<char> &UncompressedBuffer,
+                       size_t UncompressedSize) {
+  llvm_unreachable("zlib::uncompress is unavailable");
+}
+uint32_t zlib::crc32(StringRef Buffer) {
+  llvm_unreachable("zlib::crc32 is unavailable");
+}
+#endif