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-rw-r--r--libevmasm/Assembly.cpp4
-rw-r--r--libevmasm/CommonSubexpressionEliminator.h8
-rw-r--r--libevmasm/Instruction.cpp2
-rw-r--r--libevmasm/SemanticInformation.cpp7
-rw-r--r--libevmasm/SemanticInformation.h3
-rw-r--r--libsolidity/ast/Types.h13
-rw-r--r--libsolidity/codegen/CompilerUtils.cpp36
-rw-r--r--libsolidity/codegen/ExpressionCompiler.cpp21
-rw-r--r--test/libevmasm/Optimiser.cpp5
-rw-r--r--test/libsolidity/SolidityEndToEndTest.cpp23
10 files changed, 87 insertions, 35 deletions
diff --git a/libevmasm/Assembly.cpp b/libevmasm/Assembly.cpp
index bd4ebf59..b71bc80c 100644
--- a/libevmasm/Assembly.cpp
+++ b/libevmasm/Assembly.cpp
@@ -438,13 +438,15 @@ map<u256, u256> Assembly::optimiseInternal(
// function types that can be stored in storage.
AssemblyItems optimisedItems;
+ bool usesMSize = (find(m_items.begin(), m_items.end(), AssemblyItem(Instruction::MSIZE)) != m_items.end());
+
auto iter = m_items.begin();
while (iter != m_items.end())
{
KnownState emptyState;
CommonSubexpressionEliminator eliminator(emptyState);
auto orig = iter;
- iter = eliminator.feedItems(iter, m_items.end());
+ iter = eliminator.feedItems(iter, m_items.end(), usesMSize);
bool shouldReplace = false;
AssemblyItems optimisedChunk;
try
diff --git a/libevmasm/CommonSubexpressionEliminator.h b/libevmasm/CommonSubexpressionEliminator.h
index 0b957a0e..b20de246 100644
--- a/libevmasm/CommonSubexpressionEliminator.h
+++ b/libevmasm/CommonSubexpressionEliminator.h
@@ -65,8 +65,9 @@ public:
/// Feeds AssemblyItems into the eliminator and @returns the iterator pointing at the first
/// item that must be fed into a new instance of the eliminator.
+ /// @param _msizeImportant if false, do not consider modification of MSIZE a side-effect
template <class _AssemblyItemIterator>
- _AssemblyItemIterator feedItems(_AssemblyItemIterator _iterator, _AssemblyItemIterator _end);
+ _AssemblyItemIterator feedItems(_AssemblyItemIterator _iterator, _AssemblyItemIterator _end, bool _msizeImportant);
/// @returns the resulting items after optimization.
AssemblyItems getOptimizedItems();
@@ -168,11 +169,12 @@ private:
template <class _AssemblyItemIterator>
_AssemblyItemIterator CommonSubexpressionEliminator::feedItems(
_AssemblyItemIterator _iterator,
- _AssemblyItemIterator _end
+ _AssemblyItemIterator _end,
+ bool _msizeImportant
)
{
assertThrow(!m_breakingItem, OptimizerException, "Invalid use of CommonSubexpressionEliminator.");
- for (; _iterator != _end && !SemanticInformation::breaksCSEAnalysisBlock(*_iterator); ++_iterator)
+ for (; _iterator != _end && !SemanticInformation::breaksCSEAnalysisBlock(*_iterator, _msizeImportant); ++_iterator)
feedItem(*_iterator);
if (_iterator != _end)
m_breakingItem = &(*_iterator++);
diff --git a/libevmasm/Instruction.cpp b/libevmasm/Instruction.cpp
index a677a631..f9bbad2c 100644
--- a/libevmasm/Instruction.cpp
+++ b/libevmasm/Instruction.cpp
@@ -199,7 +199,7 @@ static const std::map<Instruction, InstructionInfo> c_instructionInfo =
{ Instruction::ADDMOD, { "ADDMOD", 0, 3, 1, false, Tier::Mid } },
{ Instruction::MULMOD, { "MULMOD", 0, 3, 1, false, Tier::Mid } },
{ Instruction::SIGNEXTEND, { "SIGNEXTEND", 0, 2, 1, false, Tier::Low } },
- { Instruction::KECCAK256, { "KECCAK256", 0, 2, 1, false, Tier::Special } },
+ { Instruction::KECCAK256, { "KECCAK256", 0, 2, 1, true, Tier::Special } },
{ Instruction::ADDRESS, { "ADDRESS", 0, 0, 1, false, Tier::Base } },
{ Instruction::BALANCE, { "BALANCE", 0, 1, 1, false, Tier::Balance } },
{ Instruction::ORIGIN, { "ORIGIN", 0, 0, 1, false, Tier::Base } },
diff --git a/libevmasm/SemanticInformation.cpp b/libevmasm/SemanticInformation.cpp
index 03870f7c..71267ee8 100644
--- a/libevmasm/SemanticInformation.cpp
+++ b/libevmasm/SemanticInformation.cpp
@@ -28,7 +28,7 @@ using namespace std;
using namespace dev;
using namespace dev::eth;
-bool SemanticInformation::breaksCSEAnalysisBlock(AssemblyItem const& _item)
+bool SemanticInformation::breaksCSEAnalysisBlock(AssemblyItem const& _item, bool _msizeImportant)
{
switch (_item.type())
{
@@ -59,6 +59,11 @@ bool SemanticInformation::breaksCSEAnalysisBlock(AssemblyItem const& _item)
return false;
if (_item.instruction() == Instruction::MSTORE)
return false;
+ if (!_msizeImportant && (
+ _item.instruction() == Instruction::MLOAD ||
+ _item.instruction() == Instruction::KECCAK256
+ ))
+ return false;
//@todo: We do not handle the following memory instructions for now:
// calldatacopy, codecopy, extcodecopy, mstore8,
// msize (note that msize also depends on memory read access)
diff --git a/libevmasm/SemanticInformation.h b/libevmasm/SemanticInformation.h
index 83656252..8bdc70be 100644
--- a/libevmasm/SemanticInformation.h
+++ b/libevmasm/SemanticInformation.h
@@ -38,7 +38,8 @@ class AssemblyItem;
struct SemanticInformation
{
/// @returns true if the given items starts a new block for common subexpression analysis.
- static bool breaksCSEAnalysisBlock(AssemblyItem const& _item);
+ /// @param _msizeImportant if false, consider an operation non-breaking if its only side-effect is that it modifies msize.
+ static bool breaksCSEAnalysisBlock(AssemblyItem const& _item, bool _msizeImportant);
/// @returns true if the item is a two-argument operation whose value does not depend on the
/// order of its arguments.
static bool isCommutativeOperation(AssemblyItem const& _item);
diff --git a/libsolidity/ast/Types.h b/libsolidity/ast/Types.h
index b7e64891..2c392705 100644
--- a/libsolidity/ast/Types.h
+++ b/libsolidity/ast/Types.h
@@ -229,6 +229,9 @@ public:
/// i.e. it behaves differently in lvalue context and in value context.
virtual bool isValueType() const { return false; }
virtual unsigned sizeOnStack() const { return 1; }
+ /// If it is possible to initialize such a value in memory by just writing zeros
+ /// of the size memoryHeadSize().
+ virtual bool hasSimpleZeroValueInMemory() const { return true; }
/// @returns the mobile (in contrast to static) type corresponding to the given type.
/// This returns the corresponding IntegerType or FixedPointType for RationalNumberType
/// and the pointer type for storage reference types.
@@ -568,6 +571,7 @@ public:
virtual TypePointer mobileType() const override { return copyForLocation(m_location, true); }
virtual bool dataStoredIn(DataLocation _location) const override { return m_location == _location; }
+ virtual bool hasSimpleZeroValueInMemory() const override { return false; }
/// Storage references can be pointers or bound references. In general, local variables are of
/// pointer type, state variables are bound references. Assignments to pointers or deleting
@@ -855,6 +859,7 @@ public:
virtual u256 storageSize() const override;
virtual bool canLiveOutsideStorage() const override { return false; }
virtual unsigned sizeOnStack() const override;
+ virtual bool hasSimpleZeroValueInMemory() const override { return false; }
virtual TypePointer mobileType() const override;
/// Converts components to their temporary types and performs some wildcard matching.
virtual TypePointer closestTemporaryType(TypePointer const& _targetType) const override;
@@ -999,6 +1004,7 @@ public:
virtual bool isValueType() const override { return true; }
virtual bool canLiveOutsideStorage() const override { return m_kind == Kind::Internal || m_kind == Kind::External; }
virtual unsigned sizeOnStack() const override;
+ virtual bool hasSimpleZeroValueInMemory() const override { return false; }
virtual MemberList::MemberMap nativeMembers(ContractDefinition const* _currentScope) const override;
virtual TypePointer encodingType() const override;
virtual TypePointer interfaceType(bool _inLibrary) const override;
@@ -1104,6 +1110,8 @@ public:
return _inLibrary ? shared_from_this() : TypePointer();
}
virtual bool dataStoredIn(DataLocation _location) const override { return _location == DataLocation::Storage; }
+ /// Cannot be stored in memory, but just in case.
+ virtual bool hasSimpleZeroValueInMemory() const override { solAssert(false, ""); }
TypePointer const& keyType() const { return m_keyType; }
TypePointer const& valueType() const { return m_valueType; }
@@ -1132,6 +1140,7 @@ public:
virtual u256 storageSize() const override;
virtual bool canLiveOutsideStorage() const override { return false; }
virtual unsigned sizeOnStack() const override;
+ virtual bool hasSimpleZeroValueInMemory() const override { solAssert(false, ""); }
virtual std::string toString(bool _short) const override { return "type(" + m_actualType->toString(_short) + ")"; }
virtual MemberList::MemberMap nativeMembers(ContractDefinition const* _currentScope) const override;
@@ -1154,6 +1163,7 @@ public:
virtual u256 storageSize() const override;
virtual bool canLiveOutsideStorage() const override { return false; }
virtual unsigned sizeOnStack() const override { return 0; }
+ virtual bool hasSimpleZeroValueInMemory() const override { solAssert(false, ""); }
virtual std::string richIdentifier() const override;
virtual bool operator==(Type const& _other) const override;
virtual std::string toString(bool _short) const override;
@@ -1179,6 +1189,7 @@ public:
virtual bool operator==(Type const& _other) const override;
virtual bool canBeStored() const override { return false; }
virtual bool canLiveOutsideStorage() const override { return true; }
+ virtual bool hasSimpleZeroValueInMemory() const override { solAssert(false, ""); }
virtual unsigned sizeOnStack() const override { return 0; }
virtual MemberList::MemberMap nativeMembers(ContractDefinition const*) const override;
@@ -1209,6 +1220,7 @@ public:
virtual bool operator==(Type const& _other) const override;
virtual bool canBeStored() const override { return false; }
virtual bool canLiveOutsideStorage() const override { return true; }
+ virtual bool hasSimpleZeroValueInMemory() const override { solAssert(false, ""); }
virtual unsigned sizeOnStack() const override { return 0; }
virtual MemberList::MemberMap nativeMembers(ContractDefinition const*) const override;
@@ -1238,6 +1250,7 @@ public:
virtual bool canLiveOutsideStorage() const override { return false; }
virtual bool isValueType() const override { return true; }
virtual unsigned sizeOnStack() const override { return 1; }
+ virtual bool hasSimpleZeroValueInMemory() const override { solAssert(false, ""); }
virtual std::string toString(bool) const override { return "inaccessible dynamic type"; }
virtual TypePointer decodingType() const override { return std::make_shared<IntegerType>(256); }
};
diff --git a/libsolidity/codegen/CompilerUtils.cpp b/libsolidity/codegen/CompilerUtils.cpp
index 676d5d4e..deaef017 100644
--- a/libsolidity/codegen/CompilerUtils.cpp
+++ b/libsolidity/codegen/CompilerUtils.cpp
@@ -495,14 +495,34 @@ void CompilerUtils::abiDecodeV2(TypePointers const& _parameterTypes, bool _fromM
void CompilerUtils::zeroInitialiseMemoryArray(ArrayType const& _type)
{
- auto repeat = m_context.newTag();
- m_context << repeat;
- pushZeroValue(*_type.baseType());
- storeInMemoryDynamic(*_type.baseType());
- m_context << Instruction::SWAP1 << u256(1) << Instruction::SWAP1;
- m_context << Instruction::SUB << Instruction::SWAP1;
- m_context << Instruction::DUP2;
- m_context.appendConditionalJumpTo(repeat);
+ if (_type.baseType()->hasSimpleZeroValueInMemory())
+ {
+ solAssert(_type.baseType()->isValueType(), "");
+ Whiskers templ(R"({
+ let size := mul(length, <element_size>)
+ // cheap way of zero-initializing a memory range
+ codecopy(memptr, codesize(), size)
+ memptr := add(memptr, size)
+ })");
+ templ("element_size", to_string(_type.baseType()->memoryHeadSize()));
+ m_context.appendInlineAssembly(templ.render(), {"length", "memptr"});
+ }
+ else
+ {
+ // TODO: Potential optimization:
+ // When we create a new multi-dimensional dynamic array, each element
+ // is initialized to an empty array. It actually does not hurt
+ // to re-use exactly the same empty array for all elements. Currently,
+ // a new one is created each time.
+ auto repeat = m_context.newTag();
+ m_context << repeat;
+ pushZeroValue(*_type.baseType());
+ storeInMemoryDynamic(*_type.baseType());
+ m_context << Instruction::SWAP1 << u256(1) << Instruction::SWAP1;
+ m_context << Instruction::SUB << Instruction::SWAP1;
+ m_context << Instruction::DUP2;
+ m_context.appendConditionalJumpTo(repeat);
+ }
m_context << Instruction::SWAP1 << Instruction::POP;
}
diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
index 9e2d30d5..76aa6843 100644
--- a/libsolidity/codegen/ExpressionCompiler.cpp
+++ b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -850,8 +850,6 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
}
case FunctionType::Kind::ObjectCreation:
{
- // Will allocate at the end of memory (MSIZE) and not write at all unless the base
- // type is dynamically sized.
ArrayType const& arrayType = dynamic_cast<ArrayType const&>(*_functionCall.annotation().type);
_functionCall.expression().accept(*this);
solAssert(arguments.size() == 1, "");
@@ -861,15 +859,7 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
utils().convertType(*arguments[0]->annotation().type, IntegerType(256));
// Stack: requested_length
- // Allocate at max(MSIZE, freeMemoryPointer)
utils().fetchFreeMemoryPointer();
- m_context << Instruction::DUP1 << Instruction::MSIZE;
- m_context << Instruction::LT;
- auto initialise = m_context.appendConditionalJump();
- // Free memory pointer does not point to empty memory, use MSIZE.
- m_context << Instruction::POP;
- m_context << Instruction::MSIZE;
- m_context << initialise;
// Stack: requested_length memptr
m_context << Instruction::SWAP1;
@@ -894,13 +884,10 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
// Check if length is zero
m_context << Instruction::DUP1 << Instruction::ISZERO;
auto skipInit = m_context.appendConditionalJump();
-
- // We only have to initialise if the base type is a not a value type.
- if (dynamic_cast<ReferenceType const*>(arrayType.baseType().get()))
- {
- m_context << Instruction::DUP2 << u256(32) << Instruction::ADD;
- utils().zeroInitialiseMemoryArray(arrayType);
- }
+ // Always initialize because the free memory pointer might point at
+ // a dirty memory area.
+ m_context << Instruction::DUP2 << u256(32) << Instruction::ADD;
+ utils().zeroInitialiseMemoryArray(arrayType);
m_context << skipInit;
m_context << Instruction::POP;
break;
diff --git a/test/libevmasm/Optimiser.cpp b/test/libevmasm/Optimiser.cpp
index f630b304..28f6b8c0 100644
--- a/test/libevmasm/Optimiser.cpp
+++ b/test/libevmasm/Optimiser.cpp
@@ -69,8 +69,9 @@ namespace
{
AssemblyItems input = addDummyLocations(_input);
+ bool usesMsize = (find(_input.begin(), _input.end(), AssemblyItem{Instruction::MSIZE}) != _input.end());
eth::CommonSubexpressionEliminator cse(_state);
- BOOST_REQUIRE(cse.feedItems(input.begin(), input.end()) == input.end());
+ BOOST_REQUIRE(cse.feedItems(input.begin(), input.end(), usesMsize) == input.end());
AssemblyItems output = cse.getOptimizedItems();
for (AssemblyItem const& item: output)
@@ -124,7 +125,7 @@ BOOST_AUTO_TEST_CASE(cse_intermediate_swap)
Instruction::SLOAD, Instruction::SWAP1, u256(100), Instruction::EXP, Instruction::SWAP1,
Instruction::DIV, u256(0xff), Instruction::AND
};
- BOOST_REQUIRE(cse.feedItems(input.begin(), input.end()) == input.end());
+ BOOST_REQUIRE(cse.feedItems(input.begin(), input.end(), false) == input.end());
AssemblyItems output = cse.getOptimizedItems();
BOOST_CHECK(!output.empty());
}
diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp
index f5813aed..7fd65c14 100644
--- a/test/libsolidity/SolidityEndToEndTest.cpp
+++ b/test/libsolidity/SolidityEndToEndTest.cpp
@@ -9119,7 +9119,7 @@ BOOST_AUTO_TEST_CASE(calling_uninitialized_function_in_detail)
int mutex;
function t() returns (uint) {
if (mutex > 0)
- return 7;
+ { assembly { mstore(0, 7) return(0, 0x20) } }
mutex = 1;
// Avoid re-executing this function if we jump somewhere.
x();
@@ -9132,6 +9132,27 @@ BOOST_AUTO_TEST_CASE(calling_uninitialized_function_in_detail)
ABI_CHECK(callContractFunction("t()"), encodeArgs());
}
+BOOST_AUTO_TEST_CASE(calling_uninitialized_function_through_array)
+{
+ char const* sourceCode = R"(
+ contract C {
+ int mutex;
+ function t() returns (uint) {
+ if (mutex > 0)
+ { assembly { mstore(0, 7) return(0, 0x20) } }
+ mutex = 1;
+ // Avoid re-executing this function if we jump somewhere.
+ function() internal returns (uint)[200] x;
+ x[0]();
+ return 2;
+ }
+ }
+ )";
+
+ compileAndRun(sourceCode, 0, "C");
+ ABI_CHECK(callContractFunction("t()"), encodeArgs());
+}
+
BOOST_AUTO_TEST_CASE(pass_function_types_internally)
{
char const* sourceCode = R"(
generated by cgit v1.2.3 (git 2.25.1) at 2025-02-01 03:06:50 +0800