Enable BCJ filters for X86 and ARM ELF binary.
am: 5288bd128e
Change-Id: I91591226d8006477128c782eb81448302ffb6e75
diff --git a/payload_generator/xz_android.cc b/payload_generator/xz_android.cc
index b2b74b1..41c55f7 100644
--- a/payload_generator/xz_android.cc
+++ b/payload_generator/xz_android.cc
@@ -16,12 +16,14 @@
#include "update_engine/payload_generator/xz.h"
-#include <7zCrc.h>
-#include <Xz.h>
-#include <XzEnc.h>
+#include <elf.h>
+#include <endian.h>
#include <algorithm>
+#include <7zCrc.h>
+#include <Xz.h>
+#include <XzEnc.h>
#include <base/logging.h>
namespace {
@@ -67,6 +69,37 @@
brillo::Blob* data_;
};
+// Returns the filter id to be used to compress |data|.
+// Only BCJ filter for x86 and ARM ELF file are supported, returns 0 otherwise.
+int GetFilterID(const brillo::Blob& data) {
+ if (data.size() < sizeof(Elf32_Ehdr) ||
+ memcmp(data.data(), ELFMAG, SELFMAG) != 0)
+ return 0;
+
+ const Elf32_Ehdr* header = reinterpret_cast<const Elf32_Ehdr*>(data.data());
+
+ // Only little-endian is supported.
+ if (header->e_ident[EI_DATA] != ELFDATA2LSB)
+ return 0;
+
+ switch (le16toh(header->e_machine)) {
+ case EM_386:
+ case EM_X86_64:
+ return XZ_ID_X86;
+ case EM_ARM:
+ // Both ARM and ARM Thumb instructions could be found in the same ARM ELF
+ // file. We choose to use the ARM Thumb filter here because testing shows
+ // that it usually works better than the ARM filter.
+ return XZ_ID_ARMT;
+#ifdef EM_AARCH64
+ case EM_AARCH64:
+ // Neither the ARM nor the ARM Thumb filter works well with AArch64.
+ return 0;
+#endif
+ }
+ return 0;
+}
+
} // namespace
namespace chromeos_update_engine {
@@ -107,6 +140,8 @@
Lzma2EncProps_Normalize(&lzma2Props);
props.lzma2Props = lzma2Props;
+ props.filterProps.id = GetFilterID(in);
+
BlobWriterStream out_writer(out);
BlobReaderStream in_reader(in);
SRes res = Xz_Encode(&out_writer, &in_reader, &props, nullptr /* progress */);
diff --git a/payload_generator/zip_unittest.cc b/payload_generator/zip_unittest.cc
index 5b0d5da..29f16d3 100644
--- a/payload_generator/zip_unittest.cc
+++ b/payload_generator/zip_unittest.cc
@@ -135,7 +135,7 @@
brillo::Blob decompressed;
EXPECT_TRUE(this->ZipDecompress(out, &decompressed));
EXPECT_EQ(in.size(), decompressed.size());
- EXPECT_TRUE(!memcmp(in.data(), decompressed.data(), in.size()));
+ EXPECT_EQ(0, memcmp(in.data(), decompressed.data(), in.size()));
}
TYPED_TEST(ZipTest, PoorCompressionTest) {
@@ -165,4 +165,18 @@
EXPECT_EQ(0U, out.size());
}
+TYPED_TEST(ZipTest, CompressELFTest) {
+ string path = test_utils::GetBuildArtifactsPath("delta_generator");
+ brillo::Blob in;
+ utils::ReadFile(path, &in);
+ brillo::Blob out;
+ EXPECT_TRUE(this->ZipCompress(in, &out));
+ EXPECT_LT(out.size(), in.size());
+ EXPECT_GT(out.size(), 0U);
+ brillo::Blob decompressed;
+ EXPECT_TRUE(this->ZipDecompress(out, &decompressed));
+ EXPECT_EQ(in.size(), decompressed.size());
+ EXPECT_EQ(0, memcmp(in.data(), decompressed.data(), in.size()));
+}
+
} // namespace chromeos_update_engine