[HIP] change compress level

Change compression level to 20 for zstd better
compression rate.

Author: yxsamliu

clang/lib/Driver/OffloadBundler.cpp

@@ -942,20 +942,28 @@ CompressedOffloadBundle::compress(const llvm::MemoryBuffer &Input,
       Input.getBuffer().size());
 
   llvm::compression::Format CompressionFormat;
+  int Level;
 
-  if (llvm::compression::zstd::isAvailable())
+  if (llvm::compression::zstd::isAvailable()) {
     CompressionFormat = llvm::compression::Format::Zstd;
-  else if (llvm::compression::zlib::isAvailable())
+    // Use a high zstd compress level by default for better size reduction.
+    const int DefaultZstdLevel = 20;
+    Level = DefaultZstdLevel;
+  } else if (llvm::compression::zlib::isAvailable()) {
     CompressionFormat = llvm::compression::Format::Zlib;
-  else
+    // Use default level for zlib since higher level does not have significant
+    // improvement.
+    Level = llvm::compression::zlib::DefaultCompression;
+  } else
     return createStringError(llvm::inconvertibleErrorCode(),
                              "Compression not supported");
 
   llvm::Timer CompressTimer("Compression Timer", "Compression time",
                             ClangOffloadBundlerTimerGroup);
   if (Verbose)
     CompressTimer.startTimer();
-  llvm::compression::compress(CompressionFormat, BufferUint8, CompressedBuffer);
+  llvm::compression::compress({CompressionFormat, Level}, BufferUint8,
+                              CompressedBuffer);
   if (Verbose)
     CompressTimer.stopTimer();
 
@@ -980,6 +988,7 @@ CompressedOffloadBundle::compress(const llvm::MemoryBuffer &Input,
         CompressionFormat == llvm::compression::Format::Zstd ? "zstd" : "zlib";
     llvm::errs() << "Compressed bundle format version: " << Version << "\n"
                  << "Compression method used: " << MethodUsed << "\n"
+                 << "Compression level: " << Level << "\n"
                  << "Binary size before compression: " << UncompressedSize
                  << " bytes\n"
                  << "Binary size after compression: " << CompressedBuffer.size()

clang/test/Driver/clang-offload-bundler-zlib.c

@@ -1,4 +1,4 @@
-// REQUIRES: zlib
+// REQUIRES: zlib && !zstd
 // REQUIRES: x86-registered-target
 // UNSUPPORTED: target={{.*}}-darwin{{.*}}, target={{.*}}-aix{{.*}}
 
@@ -34,7 +34,8 @@
 // RUN: diff %t.tgt2 %t.res.tgt2
 
 //
-// COMPRESS: Compression method used:
+// COMPRESS: Compression method used: zlib
+// COMPRESS: Compression level: 6
 // DECOMPRESS: Decompression method:
 // NOHOST-NOT: host-
 // NOHOST-DAG: hip-amdgcn-amd-amdhsa--gfx900

clang/test/Driver/clang-offload-bundler-zstd.c

@@ -31,7 +31,8 @@
 // RUN: diff %t.tgt1 %t.res.tgt1
 // RUN: diff %t.tgt2 %t.res.tgt2
 //
-// COMPRESS: Compression method used
+// COMPRESS: Compression method used: zstd
+// COMPRESS: Compression level: 20
 // DECOMPRESS: Decompression method
 // NOHOST-NOT: host-
 // NOHOST-DAG: hip-amdgcn-amd-amdhsa--gfx900

llvm/include/llvm/Support/Compression.h

@@ -94,6 +94,7 @@ struct Params {
   constexpr Params(Format F)
       : format(F), level(F == Format::Zlib ? zlib::DefaultCompression
                                            : zstd::DefaultCompression) {}
+  constexpr Params(Format F, int L) : format(F), level(L) {}
   Params(DebugCompressionType Type) : Params(formatFor(Type)) {}
 
   Format format;