Merge pull request #10803 from ethereum/shortcut-code-length

Implemented a shortcut  for ``address.code.length`` that generates ``…
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chriseth 2021-01-26 11:20:22 +01:00 committed by GitHub
commit b01110ee16
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6 changed files with 147 additions and 6 deletions

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@ -5,6 +5,7 @@ Language Features:
Compiler Features: Compiler Features:
* Build system: Update the soljson.js build to emscripten 2.0.12 and boost 1.75.0. * Build system: Update the soljson.js build to emscripten 2.0.12 and boost 1.75.0.
* Code Generator: Reduce the cost of ``<address>.code.length`` by using ``extcodesize`` directly.
* Command Line Interface: Allow "=" as separator between library name and address in ``--libraries`` commandline option. * Command Line Interface: Allow "=" as separator between library name and address in ``--libraries`` commandline option.
* Command Line Interface: New option ``--model-checker-targets`` allows specifying which targets should be checked. The valid options are ``all``, ``constantCondition``, ``underflow``, ``overflow``, ``divByZero``, ``balance``, ``assert``, ``popEmptyArray``, where the default is ``all``. Multiple targets can be chosen at the same time, separated by a comma without spaces: ``underflow,overflow,assert``. * Command Line Interface: New option ``--model-checker-targets`` allows specifying which targets should be checked. The valid options are ``all``, ``constantCondition``, ``underflow``, ``overflow``, ``divByZero``, ``balance``, ``assert``, ``popEmptyArray``, where the default is ``all``. Multiple targets can be chosen at the same time, separated by a comma without spaces: ``underflow,overflow,assert``.
* Command Line Interface: Only accept the library address that is prefixed with "0x" in ``--libraries`` commandline option. * Command Line Interface: Only accept the library address that is prefixed with "0x" in ``--libraries`` commandline option.

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@ -1473,6 +1473,29 @@ bool ExpressionCompiler::visit(MemberAccess const& _memberAccess)
return false; return false;
} }
// Another special case for `address.code.length`, which should simply call extcodesize
if (
auto innerExpression = dynamic_cast<MemberAccess const*>(&_memberAccess.expression());
member == "length" &&
innerExpression &&
innerExpression->memberName() == "code" &&
innerExpression->expression().annotation().type->category() == Type::Category::Address
)
{
solAssert(innerExpression->annotation().type->category() == Type::Category::Array, "");
innerExpression->expression().accept(*this);
utils().convertType(
*innerExpression->expression().annotation().type,
*TypeProvider::address(),
true
);
m_context << Instruction::EXTCODESIZE;
return false;
}
_memberAccess.expression().accept(*this); _memberAccess.expression().accept(*this);
switch (_memberAccess.expression().annotation().type->category()) switch (_memberAccess.expression().annotation().type->category())
{ {

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@ -1554,6 +1554,28 @@ void IRGeneratorForStatements::endVisit(FunctionCallOptions const& _options)
} }
} }
bool IRGeneratorForStatements::visit(MemberAccess const& _memberAccess)
{
// A shortcut for <address>.code.length. We skip visiting <address>.code and directly visit
// <address>. The actual code is generated in endVisit.
if (
auto innerExpression = dynamic_cast<MemberAccess const*>(&_memberAccess.expression());
_memberAccess.memberName() == "length" &&
innerExpression &&
innerExpression->memberName() == "code" &&
innerExpression->expression().annotation().type->category() == Type::Category::Address
)
{
solAssert(innerExpression->annotation().type->category() == Type::Category::Array, "");
// Skip visiting <address>.code
innerExpression->expression().accept(*this);
return false;
}
return true;
}
void IRGeneratorForStatements::endVisit(MemberAccess const& _memberAccess) void IRGeneratorForStatements::endVisit(MemberAccess const& _memberAccess)
{ {
setLocation(_memberAccess); setLocation(_memberAccess);
@ -1846,13 +1868,26 @@ void IRGeneratorForStatements::endVisit(MemberAccess const& _memberAccess)
case Type::Category::Array: case Type::Category::Array:
{ {
auto const& type = dynamic_cast<ArrayType const&>(*_memberAccess.expression().annotation().type); auto const& type = dynamic_cast<ArrayType const&>(*_memberAccess.expression().annotation().type);
if (member == "length") if (member == "length")
define(_memberAccess) << {
m_utils.arrayLengthFunction(type) << // shortcut for <address>.code.length
"(" << if (
IRVariable(_memberAccess.expression()).commaSeparatedList() << auto innerExpression = dynamic_cast<MemberAccess const*>(&_memberAccess.expression());
")\n"; innerExpression &&
innerExpression->memberName() == "code" &&
innerExpression->expression().annotation().type->category() == Type::Category::Address
)
define(_memberAccess) <<
"extcodesize(" <<
expressionAsType(innerExpression->expression(), *TypeProvider::address()) <<
")\n";
else
define(_memberAccess) <<
m_utils.arrayLengthFunction(type) <<
"(" <<
IRVariable(_memberAccess.expression()).commaSeparatedList() <<
")\n";
}
else if (member == "pop" || member == "push") else if (member == "pop" || member == "push")
{ {
solAssert(type.location() == DataLocation::Storage, ""); solAssert(type.location() == DataLocation::Storage, "");

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@ -87,6 +87,7 @@ public:
bool visit(BinaryOperation const& _binOp) override; bool visit(BinaryOperation const& _binOp) override;
void endVisit(FunctionCall const& _funCall) override; void endVisit(FunctionCall const& _funCall) override;
void endVisit(FunctionCallOptions const& _funCallOptions) override; void endVisit(FunctionCallOptions const& _funCallOptions) override;
bool visit(MemberAccess const& _memberAccess) override;
void endVisit(MemberAccess const& _memberAccess) override; void endVisit(MemberAccess const& _memberAccess) override;
bool visit(InlineAssembly const& _inlineAsm) override; bool visit(InlineAssembly const& _inlineAsm) override;
void endVisit(IndexAccess const& _indexAccess) override; void endVisit(IndexAccess const& _indexAccess) override;

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@ -0,0 +1,64 @@
// SPDX-License-Identifier: GPL-3.0
contract C {
uint len1;
uint len2;
constructor() {
uint mem_ptr_before;
uint mem_ptr_after;
assembly {
mem_ptr_before := mload(64)
}
len1 = address(0).code.length;
assembly {
mem_ptr_after := mload(64)
}
// To check that no memory was allocated and written.
assert(mem_ptr_before == mem_ptr_after);
len2 = address(this).code.length;
// To check that no memory was allocated and written.
assembly {
mem_ptr_after := mload(64)
}
assert(mem_ptr_before == mem_ptr_after);
}
function f() public view returns (bool r1, bool r2) {
uint mem_ptr_before;
uint mem_ptr_after;
assembly {
mem_ptr_before := mload(64)
}
r1 = address(this).code.length > 50;
assembly {
mem_ptr_after := mload(64)
}
// To check that no memory was allocated and written.
assert(mem_ptr_before == mem_ptr_after);
address a = address(0);
r2 = a.code.length == 0;
// To check that no memory was allocated and written.
assembly {
mem_ptr_after := mload(64)
}
}
}
// ====
// compileViaYul: also
// ----
// constructor()
// f(): true, true -> true, true

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@ -0,0 +1,17 @@
// Test to see if type.code.length does extcodesize(type) only when type is an address.
struct S {
bytes32 code;
bytes32 another;
}
contract C {
S s;
function f() public returns (uint, uint, bool) {
return (s.code.length, s.another.length, address(this).code.length > 50);
}
}
// ====
// compileViaYul: also
// ----
// f() -> 0x20, 0x20, true