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Block info optimization #144

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merged 3 commits into from
Sep 11, 2019
Merged

Block info optimization #144

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24eb164
Perform block analysis in dedicated struct
chfast Sep 9, 2019
3277e4d
Keep block info in instruction argument
chfast Aug 27, 2019
dd738dc
test: Refactor some analysis unit tests
chfast Sep 11, 2019
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69 changes: 44 additions & 25 deletions lib/evmone/analysis.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,21 @@

namespace evmone
{
struct block_analysis
{
int gas_cost = 0;

int stack_req = 0;
int stack_max_growth = 0;
int stack_change = 0;

/// The index of the beginblock instruction that starts the block.
/// This is the place where the analysis data is going to be dumped.
size_t begin_block_index = 0;

explicit block_analysis(size_t index) noexcept : begin_block_index{index} {}
};

inline constexpr uint64_t load64be(const unsigned char* data) noexcept
{
return uint64_t{data[7]} | (uint64_t{data[6]} << 8) | (uint64_t{data[5]} << 16) |
Expand All @@ -31,13 +46,9 @@ code_analysis analyze(evmc_revision rev, const uint8_t* code, size_t code_size)

const auto* instr_table = evmc_get_instruction_metrics_table(rev);

// Create new block.
auto block = &analysis.blocks.emplace_back();
int block_stack_change = 0;
{
auto& beginblock_instr = analysis.instrs.emplace_back(opx_beginblock_fn);
beginblock_instr.arg.number = static_cast<int>(analysis.blocks.size() - 1);
}
// Create first block.
analysis.instrs.emplace_back(opx_beginblock_fn);
auto block = block_analysis{0};

const auto code_end = code + code_size;
auto code_pos = code;
Expand All @@ -50,19 +61,12 @@ code_analysis analyze(evmc_revision rev, const uint8_t* code, size_t code_size)
const auto instr_stack_req = metrics.num_stack_arguments;
const auto instr_stack_change = metrics.num_stack_returned_items - instr_stack_req;

// TODO: Define a block_analysis struct with regular ints for analysis.
// Compress it when block is closed.
auto stack_req = instr_stack_req - block_stack_change;
if (stack_req > std::numeric_limits<decltype(block->stack_req)>::max())
stack_req = std::numeric_limits<decltype(block->stack_req)>::max();

block->stack_req = std::max(block->stack_req, static_cast<int16_t>(stack_req));
block_stack_change += instr_stack_change;
block->stack_max_growth =
static_cast<int16_t>(std::max(int{block->stack_max_growth}, block_stack_change));
block.stack_req = std::max(block.stack_req, instr_stack_req - block.stack_change);
block.stack_change += instr_stack_change;
block.stack_max_growth = std::max(block.stack_max_growth, block.stack_change);

if (metrics.gas_cost > 0) // can be -1 for undefined instruction
block->gas_cost += metrics.gas_cost;
block.gas_cost += metrics.gas_cost;

if (opcode == OP_JUMPDEST)
{
Expand Down Expand Up @@ -137,25 +141,40 @@ code_analysis analyze(evmc_revision rev, const uint8_t* code, size_t code_size)
case OP_STATICCALL:
case OP_CREATE:
case OP_CREATE2:
instr.arg.number = block->gas_cost;
instr.arg.number = block.gas_cost;
break;

case OP_PC:
instr.arg.number = static_cast<int>(code_pos - code - 1);
break;
}

// If this is a terminating instruction or the next instruction is a JUMPDEST.
if (is_terminator || (code_pos != code_end && *code_pos == OP_JUMPDEST))
{
// Create new basic block if
// this is a terminating instruction or the next instruction is a JUMPDEST.
block = &analysis.blocks.emplace_back();
block_stack_change = 0;
auto& beginblock_instr = analysis.instrs.emplace_back(opx_beginblock_fn);
beginblock_instr.arg.number = static_cast<int>(analysis.blocks.size() - 1);
// Save current block.
const auto stack_req = block.stack_req <= std::numeric_limits<int16_t>::max() ?
static_cast<int16_t>(block.stack_req) :
std::numeric_limits<int16_t>::max();
const auto stack_max_growth = static_cast<int16_t>(block.stack_max_growth);
analysis.instrs[block.begin_block_index].arg.block = {
block.gas_cost, stack_req, stack_max_growth};


// Create new block.
analysis.instrs.emplace_back(opx_beginblock_fn);
block = block_analysis{analysis.instrs.size() - 1};
}
}

// Save current block.
const auto stack_req = block.stack_req <= std::numeric_limits<int16_t>::max() ?
static_cast<int16_t>(block.stack_req) :
std::numeric_limits<int16_t>::max();
const auto stack_max_growth = static_cast<int16_t>(block.stack_max_growth);
analysis.instrs[block.begin_block_index].arg.block = {
block.gas_cost, stack_req, stack_max_growth};

// Make sure the last block is terminated.
// TODO: This is not needed if the last instruction is a terminating one.
analysis.instrs.emplace_back(fns[OP_STOP]);
Expand Down
1 change: 0 additions & 1 deletion lib/evmone/analysis.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -185,7 +185,6 @@ static_assert(sizeof(block_info) == 8);
struct code_analysis
{
std::vector<instr_info> instrs;
std::vector<block_info> blocks;

/// Storage for large push values.
std::vector<intx::uint256> push_values;
Expand Down
2 changes: 1 addition & 1 deletion lib/evmone/instructions.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1202,7 +1202,7 @@ const instr_info* op_selfdestruct(const instr_info*, execution_state& state) noe

const instr_info* opx_beginblock(const instr_info* instr, execution_state& state) noexcept
{
auto& block = state.analysis->blocks[static_cast<size_t>(instr->arg.number)];
auto& block = instr->arg.block;

if ((state.gas_left -= block.gas_cost) < 0)
return state.exit(EVMC_OUT_OF_GAS);
Expand Down
25 changes: 8 additions & 17 deletions test/unittests/analysis_test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,6 @@ TEST(analysis, example1)
ASSERT_EQ(analysis.instrs.size(), 8);

EXPECT_EQ(analysis.instrs[0].fn, op_table[OPX_BEGINBLOCK]);
EXPECT_EQ(analysis.instrs[0].arg.number, 0);
EXPECT_EQ(analysis.instrs[1].fn, op_table[OP_PUSH1]);
EXPECT_EQ(analysis.instrs[2].fn, op_table[OP_PUSH1]);
EXPECT_EQ(analysis.instrs[3].fn, op_table[OP_MSTORE8]);
Expand All @@ -30,10 +29,10 @@ TEST(analysis, example1)
EXPECT_EQ(analysis.instrs[6].fn, op_table[OP_SSTORE]);
EXPECT_EQ(analysis.instrs[7].fn, op_table[OP_STOP]);

ASSERT_EQ(analysis.blocks.size(), 1);
EXPECT_EQ(analysis.blocks[0].gas_cost, 14);
EXPECT_EQ(analysis.blocks[0].stack_req, 0);
EXPECT_EQ(analysis.blocks[0].stack_max_growth, 2);
const auto& block = analysis.instrs[0].arg.block;
EXPECT_EQ(block.gas_cost, 14);
EXPECT_EQ(block.stack_req, 0);
EXPECT_EQ(block.stack_max_growth, 2);
}

TEST(analysis, stack_up_and_down)
Expand All @@ -43,16 +42,15 @@ TEST(analysis, stack_up_and_down)

ASSERT_EQ(analysis.instrs.size(), 20);
EXPECT_EQ(analysis.instrs[0].fn, op_table[OPX_BEGINBLOCK]);
EXPECT_EQ(analysis.instrs[0].arg.number, 0);
EXPECT_EQ(analysis.instrs[1].fn, op_table[OP_DUP2]);
EXPECT_EQ(analysis.instrs[2].fn, op_table[OP_DUP1]);
EXPECT_EQ(analysis.instrs[8].fn, op_table[OP_POP]);
EXPECT_EQ(analysis.instrs[18].fn, op_table[OP_PUSH1]);

ASSERT_EQ(analysis.blocks.size(), 1);
EXPECT_EQ(analysis.blocks[0].gas_cost, 7 * 3 + 10 * 2 + 3);
EXPECT_EQ(analysis.blocks[0].stack_req, 3);
EXPECT_EQ(analysis.blocks[0].stack_max_growth, 7);
const auto& block = analysis.instrs[0].arg.block;
EXPECT_EQ(block.gas_cost, 7 * 3 + 10 * 2 + 3);
EXPECT_EQ(block.stack_req, 3);
EXPECT_EQ(block.stack_max_growth, 7);
}

TEST(analysis, push)
Expand All @@ -77,7 +75,6 @@ TEST(analysis, jumpdest_skip)
const auto code = bytecode{} + OP_STOP + OP_JUMPDEST;
auto analysis = evmone::analyze(rev, &code[0], code.size());

EXPECT_EQ(analysis.blocks.size(), 2);
ASSERT_EQ(analysis.instrs.size(), 4);
EXPECT_EQ(analysis.instrs[0].fn, op_table[OPX_BEGINBLOCK]);
EXPECT_EQ(analysis.instrs[1].fn, op_table[OP_STOP]);
Expand All @@ -90,7 +87,6 @@ TEST(analysis, jump1)
const auto code = jump(add(4, 2)) + OP_JUMPDEST + mstore(0, 3) + ret(0, 0x20) + jump(6);
const auto analysis = analyze(rev, &code[0], code.size());

ASSERT_EQ(analysis.blocks.size(), 4);
ASSERT_EQ(analysis.jumpdest_offsets.size(), 1);
ASSERT_EQ(analysis.jumpdest_targets.size(), 1);
EXPECT_EQ(analysis.jumpdest_offsets[0], 6);
Expand All @@ -105,7 +101,6 @@ TEST(analysis, empty)
bytes code;
auto analysis = evmone::analyze(rev, &code[0], code.size());

EXPECT_EQ(analysis.blocks.size(), 1);
ASSERT_EQ(analysis.instrs.size(), 2);
EXPECT_EQ(analysis.instrs[0].fn, op_table[OPX_BEGINBLOCK]);
EXPECT_EQ(analysis.instrs[1].fn, op_table[OP_STOP]);
Expand All @@ -116,7 +111,6 @@ TEST(analysis, only_jumpdest)
const auto code = bytecode{OP_JUMPDEST};
auto analysis = evmone::analyze(rev, &code[0], code.size());

ASSERT_EQ(analysis.blocks.size(), 1);
ASSERT_EQ(analysis.jumpdest_offsets.size(), 1);
ASSERT_EQ(analysis.jumpdest_targets.size(), 1);
EXPECT_EQ(analysis.jumpdest_offsets[0], 0);
Expand All @@ -128,7 +122,6 @@ TEST(analysis, jumpi_at_the_end)
const auto code = bytecode{OP_JUMPI};
auto analysis = evmone::analyze(rev, &code[0], code.size());

EXPECT_EQ(analysis.blocks.size(), 2);
ASSERT_EQ(analysis.instrs.size(), 4);
EXPECT_EQ(analysis.instrs[0].fn, op_table[OPX_BEGINBLOCK]);
EXPECT_EQ(analysis.instrs[1].fn, op_table[OP_JUMPI]);
Expand All @@ -143,7 +136,6 @@ TEST(analysis, terminated_last_block)
const auto code = ret(0, 0);
auto analysis = evmone::analyze(rev, &code[0], code.size());

EXPECT_EQ(analysis.blocks.size(), 2);
ASSERT_EQ(analysis.instrs.size(), 6);
EXPECT_EQ(analysis.instrs[0].fn, op_table[OPX_BEGINBLOCK]);
EXPECT_EQ(analysis.instrs[3].fn, op_table[OP_RETURN]);
Expand All @@ -156,7 +148,6 @@ TEST(analysis, jumpdests_groups)
const auto code = 3 * OP_JUMPDEST + push(1) + 3 * OP_JUMPDEST + push(2) + OP_JUMPI;
auto analysis = evmone::analyze(rev, &code[0], code.size());

EXPECT_EQ(analysis.blocks.size(), 7);
ASSERT_EQ(analysis.instrs.size(), 11);
EXPECT_EQ(analysis.instrs[0].fn, op_table[OP_JUMPDEST]);
EXPECT_EQ(analysis.instrs[1].fn, op_table[OP_JUMPDEST]);
Expand Down
2 changes: 1 addition & 1 deletion test/utils/dump.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@ void dump(const evmone::code_analysis& analysis)

if (c == OPX_BEGINBLOCK)
{
block = &analysis.blocks[size_t(instr.arg.number)];
block = &instr.arg.block;

const auto get_jumpdest_offset = [&analysis](size_t index) noexcept
{
Expand Down