Rewrite stackmap encoding code.
Remove most of the code related to handling of bit encodings.
The design is still same; the encodings are just more implicit.
Most of the complexity is replaced with a single BitTable class,
which is a generic purpose table of tightly bit-packed integers.
It has its own header which stores the bit-encoding of columns,
and that removes the need to handle the encodings explicitly.
Other classes, like StackMap, are accessors into the BitTable,
with named getter methods for the individual columns.
This CL saves ~1% of .oat file size (~4% of stackmap size).
Test: test-art-host-gtest
Change-Id: I7e92683753b0cc376300e3b23d892feac3670890
diff --git a/libartbase/base/bit_table_test.cc b/libartbase/base/bit_table_test.cc
new file mode 100644
index 0000000..25bfcf0
--- /dev/null
+++ b/libartbase/base/bit_table_test.cc
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "bit_table.h"
+
+#include "gtest/gtest.h"
+
+namespace art {
+
+TEST(BitTableTest, TestVarint) {
+ for (size_t start_bit_offset = 0; start_bit_offset <= 32; start_bit_offset++) {
+ uint32_t values[] = { 0, 1, 11, 12, 15, 16, 255, 256, ~1u, ~0u };
+ for (uint32_t value : values) {
+ std::vector<uint8_t> buffer;
+ size_t encode_bit_offset = start_bit_offset;
+ EncodeVarintBits(&buffer, &encode_bit_offset, value);
+
+ size_t decode_bit_offset = start_bit_offset;
+ BitMemoryRegion region(MemoryRegion(buffer.data(), buffer.size()));
+ uint32_t result = DecodeVarintBits(region, &decode_bit_offset);
+ EXPECT_EQ(encode_bit_offset, decode_bit_offset);
+ EXPECT_EQ(value, result);
+ }
+ }
+}
+
+TEST(BitTableTest, TestEmptyTable) {
+ std::vector<uint8_t> buffer;
+ size_t encode_bit_offset = 0;
+ BitTableBuilder<1> builder;
+ builder.Encode(&buffer, &encode_bit_offset);
+
+ size_t decode_bit_offset = 0;
+ BitTable<1> table(buffer.data(), buffer.size(), &decode_bit_offset);
+ EXPECT_EQ(encode_bit_offset, decode_bit_offset);
+ EXPECT_EQ(0u, table.NumRows());
+}
+
+TEST(BitTableTest, TestSingleColumnTable) {
+ constexpr uint32_t kNoValue = -1;
+ std::vector<uint8_t> buffer;
+ size_t encode_bit_offset = 0;
+ BitTableBuilder<1> builder;
+ builder.AddRow(42u);
+ builder.AddRow(kNoValue);
+ builder.AddRow(1000u);
+ builder.AddRow(kNoValue);
+ builder.Encode(&buffer, &encode_bit_offset);
+
+ size_t decode_bit_offset = 0;
+ BitTable<1> table(buffer.data(), buffer.size(), &decode_bit_offset);
+ EXPECT_EQ(encode_bit_offset, decode_bit_offset);
+ EXPECT_EQ(4u, table.NumRows());
+ EXPECT_EQ(42u, table.Get(0));
+ EXPECT_EQ(kNoValue, table.Get(1));
+ EXPECT_EQ(1000u, table.Get(2));
+ EXPECT_EQ(kNoValue, table.Get(3));
+ EXPECT_EQ(10u, table.NumColumnBits(0));
+}
+
+TEST(BitTableTest, TestUnalignedTable) {
+ for (size_t start_bit_offset = 0; start_bit_offset <= 32; start_bit_offset++) {
+ std::vector<uint8_t> buffer;
+ size_t encode_bit_offset = start_bit_offset;
+ BitTableBuilder<1> builder;
+ builder.AddRow(42u);
+ builder.Encode(&buffer, &encode_bit_offset);
+
+ size_t decode_bit_offset = start_bit_offset;
+ BitTable<1> table(buffer.data(), buffer.size(), &decode_bit_offset);
+ EXPECT_EQ(encode_bit_offset, decode_bit_offset) << " start_bit_offset=" << start_bit_offset;
+ EXPECT_EQ(1u, table.NumRows());
+ EXPECT_EQ(42u, table.Get(0));
+ }
+}
+
+TEST(BitTableTest, TestBigTable) {
+ constexpr uint32_t kNoValue = -1;
+ std::vector<uint8_t> buffer;
+ size_t encode_bit_offset = 0;
+ BitTableBuilder<4> builder;
+ builder.AddRow(42u, kNoValue, 0u, static_cast<uint32_t>(-2));
+ builder.AddRow(62u, kNoValue, 63u, static_cast<uint32_t>(-3));
+ builder.Encode(&buffer, &encode_bit_offset);
+
+ size_t decode_bit_offset = 0;
+ BitTable<4> table(buffer.data(), buffer.size(), &decode_bit_offset);
+ EXPECT_EQ(encode_bit_offset, decode_bit_offset);
+ EXPECT_EQ(2u, table.NumRows());
+ EXPECT_EQ(42u, table.Get(0, 0));
+ EXPECT_EQ(kNoValue, table.Get(0, 1));
+ EXPECT_EQ(0u, table.Get(0, 2));
+ EXPECT_EQ(static_cast<uint32_t>(-2), table.Get(0, 3));
+ EXPECT_EQ(62u, table.Get(1, 0));
+ EXPECT_EQ(kNoValue, table.Get(1, 1));
+ EXPECT_EQ(63u, table.Get(1, 2));
+ EXPECT_EQ(static_cast<uint32_t>(-3), table.Get(1, 3));
+ EXPECT_EQ(6u, table.NumColumnBits(0));
+ EXPECT_EQ(0u, table.NumColumnBits(1));
+ EXPECT_EQ(7u, table.NumColumnBits(2));
+ EXPECT_EQ(32u, table.NumColumnBits(3));
+}
+
+} // namespace art