Make llvm::crc32() work also for input sizes larger than 32 bits.
The problem was noticed by the Chrome OS toolchain folks
(crbug.com/1048445) because llvm-objcopy --add-gnu-debuglink would
insert the wrong checksum when processing a binary larger than 4 GB.
That use case regressed in 1e1e3ba2526 when we started using
llvm::crc32() in more places.
Differential revision: https://reviews.llvm.org/D74039
diff --git a/llvm/lib/Support/CRC.cpp b/llvm/lib/Support/CRC.cpp
index a3dba1a..2bc668b 100644
--- a/llvm/lib/Support/CRC.cpp
+++ b/llvm/lib/Support/CRC.cpp
@@ -85,7 +85,15 @@
#include <zlib.h>
uint32_t llvm::crc32(uint32_t CRC, ArrayRef<uint8_t> Data) {
- return ::crc32(CRC, (const Bytef *)Data.data(), Data.size());
+ // Zlib's crc32() only takes a 32-bit length, so we have to iterate for larger
+ // sizes. One could use crc32_z() instead, but that's a recent (2017) addition
+ // and may not be available on all systems.
+ do {
+ ArrayRef<uint8_t> Slice = Data.take_front(UINT32_MAX);
+ CRC = ::crc32(CRC, (const Bytef *)Slice.data(), (uInt)Slice.size());
+ Data = Data.drop_front(Slice.size());
+ } while (Data.size() > 0);
+ return CRC;
}
#endif