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Functional gas estimator.

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This commit is contained in:
chriseth 2015-05-22 10:48:54 +02:00
parent 44146e6674
commit 802d52f6a2
4 changed files with 47 additions and 17 deletions
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2
ASTPrinter.cpp
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@ -33,7 +33,7 @@ namespace solidity
ASTPrinter::ASTPrinter( ASTPrinter::ASTPrinter(
ASTNode const& _ast, ASTNode const& _ast,
string const& _source, string const& _source,
StructuralGasEstimator::ASTGasConsumption const& _gasCosts GasEstimator::ASTGasConsumption const& _gasCosts
): m_indentation(0), m_source(_source), m_ast(&_ast), m_gasCosts(_gasCosts) ): m_indentation(0), m_source(_source), m_ast(&_ast), m_gasCosts(_gasCosts)
{ {
} }

6
ASTPrinter.h
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@ -24,7 +24,7 @@
#include <ostream> #include <ostream>
#include <libsolidity/ASTVisitor.h> #include <libsolidity/ASTVisitor.h>
#include <libsolidity/StructuralGasEstimator.h> #include <libsolidity/GasEstimator.h>
namespace dev namespace dev
{ {
@ -42,7 +42,7 @@ public:
ASTPrinter( ASTPrinter(
ASTNode const& _ast, ASTNode const& _ast,
std::string const& _source = std::string(), std::string const& _source = std::string(),
StructuralGasEstimator::ASTGasConsumption const& _gasCosts = StructuralGasEstimator::ASTGasConsumption() GasEstimator::ASTGasConsumption const& _gasCosts = GasEstimator::ASTGasConsumption()
); );
/// Output the string representation of the AST to _stream. /// Output the string representation of the AST to _stream.
void print(std::ostream& _stream); void print(std::ostream& _stream);
@ -133,7 +133,7 @@ private:
int m_indentation; int m_indentation;
std::string m_source; std::string m_source;
ASTNode const* m_ast; ASTNode const* m_ast;
StructuralGasEstimator::ASTGasConsumption m_gasCosts; GasEstimator::ASTGasConsumption m_gasCosts;
std::ostream* m_ostream; std::ostream* m_ostream;
}; };

36
StructuralGasEstimator.cpp → GasEstimator.cpp
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@ -20,12 +20,14 @@
* Gas consumption estimator working alongside the AST. * Gas consumption estimator working alongside the AST.
*/ */
#include "StructuralGasEstimator.h" #include "GasEstimator.h"
#include <map> #include <map>
#include <functional> #include <functional>
#include <memory> #include <memory>
#include <libdevcore/SHA3.h>
#include <libevmasm/ControlFlowGraph.h> #include <libevmasm/ControlFlowGraph.h>
#include <libevmasm/KnownState.h> #include <libevmasm/KnownState.h>
#include <libevmasm/PathGasMeter.h>
#include <libsolidity/AST.h> #include <libsolidity/AST.h>
#include <libsolidity/ASTVisitor.h> #include <libsolidity/ASTVisitor.h>
@ -34,13 +36,13 @@ using namespace dev;
using namespace dev::eth; using namespace dev::eth;
using namespace dev::solidity; using namespace dev::solidity;
StructuralGasEstimator::ASTGasConsumptionSelfAccumulated StructuralGasEstimator::performEstimation( GasEstimator::ASTGasConsumptionSelfAccumulated GasEstimator::structuralEstimation(
AssemblyItems const& _items, AssemblyItems const& _items,
vector<ASTNode const*> const& _ast vector<ASTNode const*> const& _ast
) )
{ {
solAssert(std::count(_ast.begin(), _ast.end(), nullptr) == 0, ""); solAssert(std::count(_ast.begin(), _ast.end(), nullptr) == 0, "");
map<SourceLocation, GasMeter::GasConsumption> particularCosts; map<SourceLocation, GasConsumption> particularCosts;
ControlFlowGraph cfg(_items); ControlFlowGraph cfg(_items);
for (BasicBlock const& block: cfg.optimisedBlocks()) for (BasicBlock const& block: cfg.optimisedBlocks())
@ -72,7 +74,7 @@ StructuralGasEstimator::ASTGasConsumptionSelfAccumulated StructuralGasEstimator:
return gasCosts; return gasCosts;
} }
map<ASTNode const*, GasMeter::GasConsumption> StructuralGasEstimator::breakToStatementLevel( map<ASTNode const*, GasMeter::GasConsumption> GasEstimator::breakToStatementLevel(
ASTGasConsumptionSelfAccumulated const& _gasCosts, ASTGasConsumptionSelfAccumulated const& _gasCosts,
vector<ASTNode const*> const& _roots vector<ASTNode const*> const& _roots
) )
@ -99,7 +101,7 @@ map<ASTNode const*, GasMeter::GasConsumption> StructuralGasEstimator::breakToSta
// we use the location of a node if // we use the location of a node if
// - its statement depth is 0 or // - its statement depth is 0 or
// - its statement depth is undefined but the parent's statement depth is at least 1 // - its statement depth is undefined but the parent's statement depth is at least 1
map<ASTNode const*, GasMeter::GasConsumption> gasCosts; map<ASTNode const*, GasConsumption> gasCosts;
auto onNodeSecondPass = [&](ASTNode const& _node) auto onNodeSecondPass = [&](ASTNode const& _node)
{ {
return statementDepth.count(&_node); return statementDepth.count(&_node);
@ -121,7 +123,28 @@ map<ASTNode const*, GasMeter::GasConsumption> StructuralGasEstimator::breakToSta
return gasCosts; return gasCosts;
} }
set<ASTNode const*> StructuralGasEstimator::finestNodesAtLocation( GasEstimator::GasConsumption GasEstimator::functionalEstimation(
AssemblyItems const& _items,
string const& _signature
)
{
auto state = make_shared<KnownState>();
ExpressionClasses& classes = state->expressionClasses();
using Id = ExpressionClasses::Id;
using Ids = vector<Id>;
Id hashValue = classes.find(u256(FixedHash<4>::Arith(FixedHash<4>(dev::sha3(_signature)))));
Id calldata = classes.find(eth::Instruction::CALLDATALOAD, Ids{classes.find(u256(0))});
classes.forceEqual(hashValue, eth::Instruction::DIV, Ids{
calldata,
classes.find(u256(1) << (8 * 28))
});
PathGasMeter meter(_items);
return meter.estimateMax(0, state);
}
set<ASTNode const*> GasEstimator::finestNodesAtLocation(
vector<ASTNode const*> const& _roots vector<ASTNode const*> const& _roots
) )
{ {
@ -140,4 +163,3 @@ set<ASTNode const*> StructuralGasEstimator::finestNodesAtLocation(
root->accept(visitor); root->accept(visitor);
return nodes; return nodes;
} }

20
StructuralGasEstimator.h → GasEstimator.h
View File

@ -34,17 +34,18 @@ namespace dev
namespace solidity namespace solidity
{ {
class StructuralGasEstimator struct GasEstimator
{ {
public: public:
using ASTGasConsumption = std::map<ASTNode const*, eth::GasMeter::GasConsumption>; using GasConsumption = eth::GasMeter::GasConsumption;
using ASTGasConsumption = std::map<ASTNode const*, GasConsumption>;
using ASTGasConsumptionSelfAccumulated = using ASTGasConsumptionSelfAccumulated =
std::map<ASTNode const*, std::array<eth::GasMeter::GasConsumption, 2>>; std::map<ASTNode const*, std::array<GasConsumption, 2>>;
/// Estimates the gas consumption for every assembly item in the given assembly and stores /// Estimates the gas consumption for every assembly item in the given assembly and stores
/// it by source location. /// it by source location.
/// @returns a mapping from each AST node to a pair of its particular and syntactically accumulated gas costs. /// @returns a mapping from each AST node to a pair of its particular and syntactically accumulated gas costs.
ASTGasConsumptionSelfAccumulated performEstimation( static ASTGasConsumptionSelfAccumulated structuralEstimation(
eth::AssemblyItems const& _items, eth::AssemblyItems const& _items,
std::vector<ASTNode const*> const& _ast std::vector<ASTNode const*> const& _ast
); );
@ -52,14 +53,21 @@ public:
/// the following source locations are part of the mapping: /// the following source locations are part of the mapping:
/// 1. source locations of statements that do not contain other statements /// 1. source locations of statements that do not contain other statements
/// 2. maximal source locations that do not overlap locations coming from the first rule /// 2. maximal source locations that do not overlap locations coming from the first rule
ASTGasConsumption breakToStatementLevel( static ASTGasConsumption breakToStatementLevel(
ASTGasConsumptionSelfAccumulated const& _gasCosts, ASTGasConsumptionSelfAccumulated const& _gasCosts,
std::vector<ASTNode const*> const& _roots std::vector<ASTNode const*> const& _roots
); );
/// @returns the estimated gas consumption by the (public or external) function with the
/// given signature. If no signature is given, estimates the maximum gas usage.
static GasConsumption functionalEstimation(
eth::AssemblyItems const& _items,
std::string const& _signature = ""
);
private: private:
/// @returns the set of AST nodes which are the finest nodes at their location. /// @returns the set of AST nodes which are the finest nodes at their location.
std::set<ASTNode const*> finestNodesAtLocation(std::vector<ASTNode const*> const& _roots); static std::set<ASTNode const*> finestNodesAtLocation(std::vector<ASTNode const*> const& _roots);
}; };
} }