[HIP] Support compressing device binary

Add option -f[no-]offload-compress to clang to enable/disable
compression of device binary for HIP. By default it is disabled.

Add option -compress to clang-offload-bundler to enable
compression of offload bundle. By default it is disabled.

When enabled, zstd or zlib is used for compression when
available.

When disabled, it is NFC compared to previous behavior. The
same offload bundle format is used as before.

Clang-offload-bundler automatically detects whether the
input file to be unbundled is compressed and the compression
method and decompress if necessary.

Author: yxsamliu

clang/docs/ClangOffloadBundler.rst

@@ -309,3 +309,30 @@ target by comparing bundle ID's. Two bundle ID's are considered compatible if:
   * Their offload kind are the same
   * Their target triple are the same
   * Their GPUArch are the same
+
+Compression and Decompression
+=============================
+
+``clang-offload-bundler`` provides features to compress and decompress the full
+bundle, leveraging inherent redundancies within the bundle entries. Use the
+`-compress` command-line option to enable this compression capability.
+
+The compressed offload bundle begins with a header followed by the compressed binary data:
+
+- **Magic Number (4 bytes)**:
+    This is a unique identifier to distinguish compressed offload bundles. The value is the string 'CCOB' (Compressed Clang Offload Bundle).
+
+- **Version Number (16-bit unsigned int)**:
+    This denotes the version of the compressed offload bundle format. The current version is `1`.
+
+- **Compression Method (16-bit unsigned int)**:
+    This field indicates the compression method used. The value corresponds to either `zlib` or `zstd`, represented as a 16-bit unsigned integer cast from the LLVM compression enumeration.
+
+- **Uncompressed Binary Size (32-bit unsigned int)**:
+    This is the size (in bytes) of the binary data before it was compressed.
+
+- **Hash (64-bit unsigned int)**:
+    This is a 64-bit truncated MD5 hash of the uncompressed binary data. It serves for verification and caching purposes.
+
+- **Compressed Data**:
+    The actual compressed binary data follows the header. Its size can be inferred from the total size of the file minus the header size.

clang/include/clang/Driver/OffloadBundler.h

@@ -19,18 +19,23 @@
 
 #include "llvm/Support/Error.h"
 #include "llvm/TargetParser/Triple.h"
+#include <llvm/Support/MemoryBuffer.h>
 #include <string>
 #include <vector>
 
 namespace clang {
 
 class OffloadBundlerConfig {
 public:
+  OffloadBundlerConfig();
+
   bool AllowNoHost = false;
   bool AllowMissingBundles = false;
   bool CheckInputArchive = false;
   bool PrintExternalCommands = false;
   bool HipOpenmpCompatible = false;
+  bool Compress = false;
+  bool Verbose = false;
 
   unsigned BundleAlignment = 1;
   unsigned HostInputIndex = ~0u;
@@ -84,6 +89,38 @@ struct OffloadTargetInfo {
   std::string str() const;
 };
 
+// CompressedOffloadBundle represents the format for the compressed offload
+// bundles.
+//
+// The format is as follows:
+// - Magic Number (4 bytes) - A constant "CCOB".
+// - Version (2 bytes)
+// - Compression Method (2 bytes) - Uses the values from
+// llvm::compression::Format.
+// - Uncompressed Size (4 bytes).
+// - Truncated MD5 Hash (8 bytes).
+// - Compressed Data (variable length).
+
+class CompressedOffloadBundle {
+private:
+  static inline const size_t MagicSize = 4;
+  static inline const size_t VersionFieldSize = sizeof(uint16_t);
+  static inline const size_t MethodFieldSize = sizeof(uint16_t);
+  static inline const size_t SizeFieldSize = sizeof(uint32_t);
+  static inline const size_t HashFieldSize = 8;
+  static inline const size_t HeaderSize = MagicSize + VersionFieldSize +
+                                          MethodFieldSize + SizeFieldSize +
+                                          HashFieldSize;
+  static inline const llvm::StringRef MagicNumber = "CCOB";
+  static inline const uint16_t Version = 1;
+
+public:
+  static llvm::Expected<std::unique_ptr<llvm::MemoryBuffer>>
+  compress(const llvm::MemoryBuffer &Input, bool Verbose = false);
+  static llvm::Expected<std::unique_ptr<llvm::MemoryBuffer>>
+  decompress(const llvm::MemoryBuffer &Input, bool Verbose = false);
+};
+
 } // namespace clang
 
 #endif // LLVM_CLANG_DRIVER_OFFLOADBUNDLER_H

clang/include/clang/Driver/Options.td

@@ -1183,6 +1183,10 @@ def fgpu_inline_threshold_EQ : Joined<["-"], "fgpu-inline-threshold=">,
 def fgpu_sanitize : Flag<["-"], "fgpu-sanitize">, Group<f_Group>,
   HelpText<"Enable sanitizer for supported offloading devices">;
 def fno_gpu_sanitize : Flag<["-"], "fno-gpu-sanitize">, Group<f_Group>;
+
+def offload_compress : Flag<["--"], "offload-compress">,
+  HelpText<"Compress offload device binaries (HIP only)">;
+def no_offload_compress : Flag<["--"], "no-offload-compress">;
 }
 
 // CUDA options