Index: include/llvm/Support/CRC.h
===================================================================
--- include/llvm/Support/CRC.h
+++ include/llvm/Support/CRC.h
@@ -0,0 +1,25 @@
+//===-- llvm/Support/CRC.h - Cyclic Redundancy Check-------------*- C++ -*-===//
+//
+// 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 contains basic functions for calculating Cyclic Redundancy Check
+// or CRC.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_CRC_H
+#define LLVM_SUPPORT_CRC_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/DataTypes.h"
+
+namespace llvm {
+// zlib independent CRC32 calculation.
+uint32_t getCRC32(uint32_t CRC, StringRef S);
+} // end namespace llvm
+
+#endif
Index: lib/DebugInfo/Symbolize/Symbolize.cpp
===================================================================
--- lib/DebugInfo/Symbolize/Symbolize.cpp
+++ lib/DebugInfo/Symbolize/Symbolize.cpp
@@ -23,6 +23,7 @@
 #include "llvm/Object/COFF.h"
 #include "llvm/Object/MachO.h"
 #include "llvm/Object/MachOUniversal.h"
+#include "llvm/Support/CRC.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Compression.h"
 #include "llvm/Support/DataExtractor.h"
@@ -163,7 +164,9 @@
       MemoryBuffer::getFileOrSTDIN(Path);
   if (!MB)
     return false;
-  return !zlib::isAvailable() || CRCHash == zlib::crc32(MB.get()->getBuffer());
+  return CRCHash == (zlib::isAvailable()
+                         ? zlib::crc32(MB.get()->getBuffer())
+                         : llvm::getCRC32(0, MB.get()->getBuffer()));
 }
 
 bool findDebugBinary(const std::string &OrigPath,
Index: lib/Support/CMakeLists.txt
===================================================================
--- lib/Support/CMakeLists.txt
+++ lib/Support/CMakeLists.txt
@@ -76,6 +76,7 @@
   CodeGenCoverage.cpp
   CommandLine.cpp
   Compression.cpp
+  CRC.cpp
   ConvertUTF.cpp
   ConvertUTFWrapper.cpp
   CrashRecoveryContext.cpp
Index: lib/Support/CRC.cpp
===================================================================
--- lib/Support/CRC.cpp
+++ lib/Support/CRC.cpp
@@ -0,0 +1,70 @@
+//===--- CRC.cpp - Cyclic Redundancy Check 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 getCRC32 function.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/CRC.h"
+#include "llvm/ADT/StringRef.h"
+
+using namespace llvm;
+
+static const uint32_t CRCTable[] = {
+    0X00000000, 0X77073096, 0XEE0E612C, 0X990951BA, 0X076DC419, 0X706AF48F,
+    0XE963A535, 0X9E6495A3, 0X0EDB8832, 0X79DCB8A4, 0XE0D5E91E, 0X97D2D988,
+    0X09B64C2B, 0X7EB17CBD, 0XE7B82D07, 0X90BF1D91, 0X1DB71064, 0X6AB020F2,
+    0XF3B97148, 0X84BE41DE, 0X1ADAD47D, 0X6DDDE4EB, 0XF4D4B551, 0X83D385C7,
+    0X136C9856, 0X646BA8C0, 0XFD62F97A, 0X8A65C9EC, 0X14015C4F, 0X63066CD9,
+    0XFA0F3D63, 0X8D080DF5, 0X3B6E20C8, 0X4C69105E, 0XD56041E4, 0XA2677172,
+    0X3C03E4D1, 0X4B04D447, 0XD20D85FD, 0XA50AB56B, 0X35B5A8FA, 0X42B2986C,
+    0XDBBBC9D6, 0XACBCF940, 0X32D86CE3, 0X45DF5C75, 0XDCD60DCF, 0XABD13D59,
+    0X26D930AC, 0X51DE003A, 0XC8D75180, 0XBFD06116, 0X21B4F4B5, 0X56B3C423,
+    0XCFBA9599, 0XB8BDA50F, 0X2802B89E, 0X5F058808, 0XC60CD9B2, 0XB10BE924,
+    0X2F6F7C87, 0X58684C11, 0XC1611DAB, 0XB6662D3D, 0X76DC4190, 0X01DB7106,
+    0X98D220BC, 0XEFD5102A, 0X71B18589, 0X06B6B51F, 0X9FBFE4A5, 0XE8B8D433,
+    0X7807C9A2, 0X0F00F934, 0X9609A88E, 0XE10E9818, 0X7F6A0DBB, 0X086D3D2D,
+    0X91646C97, 0XE6635C01, 0X6B6B51F4, 0X1C6C6162, 0X856530D8, 0XF262004E,
+    0X6C0695ED, 0X1B01A57B, 0X8208F4C1, 0XF50FC457, 0X65B0D9C6, 0X12B7E950,
+    0X8BBEB8EA, 0XFCB9887C, 0X62DD1DDF, 0X15DA2D49, 0X8CD37CF3, 0XFBD44C65,
+    0X4DB26158, 0X3AB551CE, 0XA3BC0074, 0XD4BB30E2, 0X4ADFA541, 0X3DD895D7,
+    0XA4D1C46D, 0XD3D6F4FB, 0X4369E96A, 0X346ED9FC, 0XAD678846, 0XDA60B8D0,
+    0X44042D73, 0X33031DE5, 0XAA0A4C5F, 0XDD0D7CC9, 0X5005713C, 0X270241AA,
+    0XBE0B1010, 0XC90C2086, 0X5768B525, 0X206F85B3, 0XB966D409, 0XCE61E49F,
+    0X5EDEF90E, 0X29D9C998, 0XB0D09822, 0XC7D7A8B4, 0X59B33D17, 0X2EB40D81,
+    0XB7BD5C3B, 0XC0BA6CAD, 0XEDB88320, 0X9ABFB3B6, 0X03B6E20C, 0X74B1D29A,
+    0XEAD54739, 0X9DD277AF, 0X04DB2615, 0X73DC1683, 0XE3630B12, 0X94643B84,
+    0X0D6D6A3E, 0X7A6A5AA8, 0XE40ECF0B, 0X9309FF9D, 0X0A00AE27, 0X7D079EB1,
+    0XF00F9344, 0X8708A3D2, 0X1E01F268, 0X6906C2FE, 0XF762575D, 0X806567CB,
+    0X196C3671, 0X6E6B06E7, 0XFED41B76, 0X89D32BE0, 0X10DA7A5A, 0X67DD4ACC,
+    0XF9B9DF6F, 0X8EBEEFF9, 0X17B7BE43, 0X60B08ED5, 0XD6D6A3E8, 0XA1D1937E,
+    0X38D8C2C4, 0X4FDFF252, 0XD1BB67F1, 0XA6BC5767, 0X3FB506DD, 0X48B2364B,
+    0XD80D2BDA, 0XAF0A1B4C, 0X36034AF6, 0X41047A60, 0XDF60EFC3, 0XA867DF55,
+    0X316E8EEF, 0X4669BE79, 0XCB61B38C, 0XBC66831A, 0X256FD2A0, 0X5268E236,
+    0XCC0C7795, 0XBB0B4703, 0X220216B9, 0X5505262F, 0XC5BA3BBE, 0XB2BD0B28,
+    0X2BB45A92, 0X5CB36A04, 0XC2D7FFA7, 0XB5D0CF31, 0X2CD99E8B, 0X5BDEAE1D,
+    0X9B64C2B0, 0XEC63F226, 0X756AA39C, 0X026D930A, 0X9C0906A9, 0XEB0E363F,
+    0X72076785, 0X05005713, 0X95BF4A82, 0XE2B87A14, 0X7BB12BAE, 0X0CB61B38,
+    0X92D28E9B, 0XE5D5BE0D, 0X7CDCEFB7, 0X0BDBDF21, 0X86D3D2D4, 0XF1D4E242,
+    0X68DDB3F8, 0X1FDA836E, 0X81BE16CD, 0XF6B9265B, 0X6FB077E1, 0X18B74777,
+    0X88085AE6, 0XFF0F6A70, 0X66063BCA, 0X11010B5C, 0X8F659EFF, 0XF862AE69,
+    0X616BFFD3, 0X166CCF45, 0XA00AE278, 0XD70DD2EE, 0X4E048354, 0X3903B3C2,
+    0XA7672661, 0XD06016F7, 0X4969474D, 0X3E6E77DB, 0XAED16A4A, 0XD9D65ADC,
+    0X40DF0B66, 0X37D83BF0, 0XA9BCAE53, 0XDEBB9EC5, 0X47B2CF7F, 0X30B5FFE9,
+    0XBDBDF21C, 0XCABAC28A, 0X53B39330, 0X24B4A3A6, 0XBAD03605, 0XCDD70693,
+    0X54DE5729, 0X23D967BF, 0XB3667A2E, 0XC4614AB8, 0X5D681B02, 0X2A6F2B94,
+    0XB40BBE37, 0XC30C8EA1, 0X5A05DF1B, 0X2D02EF8D};
+
+uint32_t llvm::getCRC32(uint32_t CRC, StringRef S) {
+  CRC ^= 0XFFFFFFFF;
+  for (char C : S) {
+    uint32_t I = (CRC ^ C) & 0xFF;
+    CRC = (CRC >> 8) ^ CRCTable[I];
+  }
+  return CRC ^ 0xFFFFFFFF;
+}
Index: unittests/Support/CMakeLists.txt
===================================================================
--- unittests/Support/CMakeLists.txt
+++ unittests/Support/CMakeLists.txt
@@ -18,6 +18,7 @@
   CommandLineTest.cpp
   CompressionTest.cpp
   ConvertUTFTest.cpp
+  CRCTest.cpp
   DataExtractorTest.cpp
   DebugTest.cpp
   DebugCounterTest.cpp
Index: unittests/Support/CRCTest.cpp
===================================================================
--- unittests/Support/CRCTest.cpp
+++ unittests/Support/CRCTest.cpp
@@ -0,0 +1,26 @@
+//===- llvm/unittest/Support/CRCTest.cpp - CRC tests ----------------------===//
+//
+// 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 unit tests for CRC calculation functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/CRC.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+TEST(CRCTest, CRC32) {
+  EXPECT_EQ(0x414FA339U,
+            llvm::getCRC32(
+                0, StringRef("The quick brown fox jumps over the lazy dog")));
+}
+
+} // end anonymous namespace