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Merge pull request #8063 from ethereum/yulvisit-7656

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Use yul::AstWalker for assembly reference resolving
This commit is contained in:
Mathias L. Baumann 2020-01-29 14:56:19 +01:00 committed by GitHub
commit 5130a2b0ae
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8 changed files with 468 additions and 83 deletions
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167
libsolidity/analysis/ReferencesResolver.cpp
View File

@ -270,87 +270,10 @@ bool ReferencesResolver::visit(InlineAssembly const& _inlineAssembly)
{
m_resolver.warnVariablesNamedLikeInstructions();
// Errors created in this stage are completely ignored because we do not yet know
// the type and size of external identifiers, which would result in false errors.
// The only purpose of this step is to fill the inline assembly annotation with
// external references.
ErrorList errors;
ErrorReporter errorsIgnored(errors);
yul::ExternalIdentifierAccess::Resolver resolver =
[&](yul::Identifier const& _identifier, yul::IdentifierContext _context, bool _crossesFunctionBoundary) {
bool isSlot = boost::algorithm::ends_with(_identifier.name.str(), "_slot");
bool isOffset = boost::algorithm::ends_with(_identifier.name.str(), "_offset");
if (_context == yul::IdentifierContext::VariableDeclaration)
{
string namePrefix = _identifier.name.str().substr(0, _identifier.name.str().find('.'));
if (isSlot || isOffset)
declarationError(_identifier.location, "In variable declarations _slot and _offset can not be used as a suffix.");
else if (
auto declarations = m_resolver.nameFromCurrentScope(namePrefix);
!declarations.empty()
)
{
SecondarySourceLocation ssl;
for (auto const* decl: declarations)
ssl.append("The shadowed declaration is here:", decl->location());
if (!ssl.infos.empty())
declarationError(
_identifier.location,
ssl,
namePrefix.size() < _identifier.name.str().size() ?
"The prefix of this declaration conflicts with a declaration outside the inline assembly block." :
"This declaration shadows a declaration outside the inline assembly block."
);
}
return size_t(-1);
}
auto declarations = m_resolver.nameFromCurrentScope(_identifier.name.str());
if (isSlot || isOffset)
{
// special mode to access storage variables
if (!declarations.empty())
// the special identifier exists itself, we should not allow that.
return size_t(-1);
string realName = _identifier.name.str().substr(0, _identifier.name.str().size() - (
isSlot ?
string("_slot").size() :
string("_offset").size()
));
if (realName.empty())
{
declarationError(_identifier.location, "In variable names _slot and _offset can only be used as a suffix.");
return size_t(-1);
}
declarations = m_resolver.nameFromCurrentScope(realName);
}
if (declarations.size() > 1)
{
declarationError(_identifier.location, "Multiple matching identifiers. Resolving overloaded identifiers is not supported.");
return size_t(-1);
}
else if (declarations.size() == 0)
return size_t(-1);
if (auto var = dynamic_cast<VariableDeclaration const*>(declarations.front()))
if (var->isLocalVariable() && _crossesFunctionBoundary)
{
declarationError(_identifier.location, "Cannot access local Solidity variables from inside an inline assembly function.");
return size_t(-1);
}
_inlineAssembly.annotation().externalReferences[&_identifier].isSlot = isSlot;
_inlineAssembly.annotation().externalReferences[&_identifier].isOffset = isOffset;
_inlineAssembly.annotation().externalReferences[&_identifier].declaration = declarations.front();
return size_t(1);
};
m_yulAnnotation = &_inlineAssembly.annotation();
(*this)(_inlineAssembly.operations());
m_yulAnnotation = nullptr;
// Will be re-generated later with correct information
// We use the latest EVM version because we will re-run it anyway.
yul::AsmAnalysisInfo analysisInfo;
yul::AsmAnalyzer(
analysisInfo,
errorsIgnored,
yul::EVMDialect::strictAssemblyForEVM(m_evmVersion),
resolver
).analyze(_inlineAssembly.operations());
return false;
}
@ -468,6 +391,90 @@ void ReferencesResolver::endVisit(VariableDeclaration const& _variable)
_variable.annotation().type = type;
}
void ReferencesResolver::operator()(yul::FunctionDefinition const& _function)
{
bool wasInsideFunction = m_yulInsideFunction;
m_yulInsideFunction = true;
this->operator()(_function.body);
m_yulInsideFunction = wasInsideFunction;
}
void ReferencesResolver::operator()(yul::Identifier const& _identifier)
{
bool isSlot = boost::algorithm::ends_with(_identifier.name.str(), "_slot");
bool isOffset = boost::algorithm::ends_with(_identifier.name.str(), "_offset");
auto declarations = m_resolver.nameFromCurrentScope(_identifier.name.str());
if (isSlot || isOffset)
{
// special mode to access storage variables
if (!declarations.empty())
// the special identifier exists itself, we should not allow that.
return;
string realName = _identifier.name.str().substr(0, _identifier.name.str().size() - (
isSlot ?
string("_slot").size() :
string("_offset").size()
));
if (realName.empty())
{
declarationError(_identifier.location, "In variable names _slot and _offset can only be used as a suffix.");
return;
}
declarations = m_resolver.nameFromCurrentScope(realName);
}
if (declarations.size() > 1)
{
declarationError(_identifier.location, "Multiple matching identifiers. Resolving overloaded identifiers is not supported.");
return;
}
else if (declarations.size() == 0)
return;
if (auto var = dynamic_cast<VariableDeclaration const*>(declarations.front()))
if (var->isLocalVariable() && m_yulInsideFunction)
{
declarationError(_identifier.location, "Cannot access local Solidity variables from inside an inline assembly function.");
return;
}
m_yulAnnotation->externalReferences[&_identifier].isSlot = isSlot;
m_yulAnnotation->externalReferences[&_identifier].isOffset = isOffset;
m_yulAnnotation->externalReferences[&_identifier].declaration = declarations.front();
}
void ReferencesResolver::operator()(yul::VariableDeclaration const& _varDecl)
{
for (auto const& identifier: _varDecl.variables)
{
bool isSlot = boost::algorithm::ends_with(identifier.name.str(), "_slot");
bool isOffset = boost::algorithm::ends_with(identifier.name.str(), "_offset");
string namePrefix = identifier.name.str().substr(0, identifier.name.str().find('.'));
if (isSlot || isOffset)
declarationError(identifier.location, "In variable declarations _slot and _offset can not be used as a suffix.");
else if (
auto declarations = m_resolver.nameFromCurrentScope(namePrefix);
!declarations.empty()
)
{
SecondarySourceLocation ssl;
for (auto const* decl: declarations)
ssl.append("The shadowed declaration is here:", decl->location());
if (!ssl.infos.empty())
declarationError(
identifier.location,
ssl,
namePrefix.size() < identifier.name.str().size() ?
"The prefix of this declaration conflicts with a declaration outside the inline assembly block." :
"This declaration shadows a declaration outside the inline assembly block."
);
}
}
if (_varDecl.value)
visit(*_varDecl.value);
}
void ReferencesResolver::typeError(SourceLocation const& _location, string const& _description)
{
m_errorOccurred = true;

13
libsolidity/analysis/ReferencesResolver.h
View File

@ -25,6 +25,7 @@
#include <libsolidity/ast/ASTVisitor.h>
#include <libsolidity/ast/ASTAnnotations.h>
#include <liblangutil/EVMVersion.h>
#include <libyul/optimiser/ASTWalker.h>
#include <boost/noncopyable.hpp>
#include <list>
@ -45,7 +46,7 @@ class NameAndTypeResolver;
* Resolves references to declarations (of variables and types) and also establishes the link
* between a return statement and the return parameter list.
*/
class ReferencesResolver: private ASTConstVisitor
class ReferencesResolver: private ASTConstVisitor, private yul::ASTWalker
{
public:
ReferencesResolver(
@ -64,6 +65,9 @@ public:
bool resolve(ASTNode const& _root);
private:
using yul::ASTWalker::visit;
using yul::ASTWalker::operator();
bool visit(Block const& _block) override;
void endVisit(Block const& _block) override;
bool visit(ForStatement const& _for) override;
@ -83,6 +87,10 @@ private:
bool visit(Return const& _return) override;
void endVisit(VariableDeclaration const& _variable) override;
void operator()(yul::FunctionDefinition const& _function) override;
void operator()(yul::Identifier const& _identifier) override;
void operator()(yul::VariableDeclaration const& _varDecl) override;
/// Adds a new error to the list of errors.
void typeError(langutil::SourceLocation const& _location, std::string const& _description);
@ -105,6 +113,9 @@ private:
std::vector<ParameterList const*> m_returnParameters;
bool const m_resolveInsideCode;
bool m_errorOccurred = false;
InlineAssemblyAnnotation* m_yulAnnotation = nullptr;
bool m_yulInsideFunction = false;
};
}

166
test/libsolidity/ASTJSON/assembly/nested_functions.json Normal file
View File

@ -0,0 +1,166 @@
{
"absolutePath": "a",
"exportedSymbols":
{
"C":
[
8
]
},
"id": 9,
"nodeType": "SourceUnit",
"nodes":
[
{
"abstract": false,
"baseContracts": [],
"contractDependencies": [],
"contractKind": "contract",
"documentation": null,
"fullyImplemented": true,
"id": 8,
"linearizedBaseContracts":
[
8
],
"name": "C",
"nodeType": "ContractDefinition",
"nodes":
[
{
"body":
{
"id": 6,
"nodeType": "Block",
"src": "57:97:1",
"statements":
[
{
"AST":
{
"nodeType": "YulBlock",
"src": "72:78:1",
"statements":
[
{
"body":
{
"nodeType": "YulBlock",
"src": "94:50:1",
"statements":
[
{
"body":
{
"nodeType": "YulBlock",
"src": "118:3:1",
"statements": []
},
"name": "f2",
"nodeType": "YulFunctionDefinition",
"src": "104:17:1"
},
{
"nodeType": "YulAssignment",
"src": "130:6:1",
"value":
{
"kind": "number",
"nodeType": "YulLiteral",
"src": "135:1:1",
"type": "",
"value": "2"
},
"variableNames":
[
{
"name": "x",
"nodeType": "YulIdentifier",
"src": "130:1:1"
}
]
}
]
},
"name": "f1",
"nodeType": "YulFunctionDefinition",
"src": "80:64:1"
}
]
},
"evmVersion": %EVMVERSION%,
"externalReferences": [],
"id": 5,
"nodeType": "InlineAssembly",
"src": "63:87:1"
}
]
},
"documentation": null,
"functionSelector": "26121ff0",
"id": 7,
"implemented": true,
"kind": "function",
"modifiers": [],
"name": "f",
"nodeType": "FunctionDefinition",
"overrides": null,
"parameters":
{
"id": 1,
"nodeType": "ParameterList",
"parameters": [],
"src": "25:2:1"
},
"returnParameters":
{
"id": 4,
"nodeType": "ParameterList",
"parameters":
[
{
"constant": false,
"id": 3,
"name": "x",
"nodeType": "VariableDeclaration",
"overrides": null,
"scope": 7,
"src": "49:6:1",
"stateVariable": false,
"storageLocation": "default",
"typeDescriptions":
{
"typeIdentifier": "t_uint256",
"typeString": "uint256"
},
"typeName":
{
"id": 2,
"name": "uint",
"nodeType": "ElementaryTypeName",
"src": "49:4:1",
"typeDescriptions":
{
"typeIdentifier": "t_uint256",
"typeString": "uint256"
}
},
"value": null,
"visibility": "internal"
}
],
"src": "48:8:1"
},
"scope": 8,
"src": "15:139:1",
"stateMutability": "pure",
"virtual": false,
"visibility": "public"
}
],
"scope": 9,
"src": "0:156:1"
}
],
"src": "0:157:1"
}

12
test/libsolidity/ASTJSON/assembly/nested_functions.sol Normal file
View File

@ -0,0 +1,12 @@
contract C {
function f() public pure returns (uint x) {
assembly {
function f1() {
function f2() { }
x := 2
}
}
}
}
// ----

148
test/libsolidity/ASTJSON/assembly/nested_functions_legacy.json Normal file
View File

@ -0,0 +1,148 @@
{
"attributes":
{
"absolutePath": "a",
"exportedSymbols":
{
"C":
[
8
]
}
},
"children":
[
{
"attributes":
{
"abstract": false,
"baseContracts":
[
null
],
"contractDependencies":
[
null
],
"contractKind": "contract",
"documentation": null,
"fullyImplemented": true,
"linearizedBaseContracts":
[
8
],
"name": "C",
"scope": 9
},
"children":
[
{
"attributes":
{
"documentation": null,
"functionSelector": "26121ff0",
"implemented": true,
"isConstructor": false,
"kind": "function",
"modifiers":
[
null
],
"name": "f",
"overrides": null,
"scope": 8,
"stateMutability": "pure",
"virtual": false,
"visibility": "public"
},
"children":
[
{
"attributes":
{
"parameters":
[
null
]
},
"children": [],
"id": 1,
"name": "ParameterList",
"src": "25:2:1"
},
{
"children":
[
{
"attributes":
{
"constant": false,
"name": "x",
"overrides": null,
"scope": 7,
"stateVariable": false,
"storageLocation": "default",
"type": "uint256",
"value": null,
"visibility": "internal"
},
"children":
[
{
"attributes":
{
"name": "uint",
"type": "uint256"
},
"id": 2,
"name": "ElementaryTypeName",
"src": "49:4:1"
}
],
"id": 3,
"name": "VariableDeclaration",
"src": "49:6:1"
}
],
"id": 4,
"name": "ParameterList",
"src": "48:8:1"
},
{
"children":
[
{
"attributes":
{
"evmVersion": %EVMVERSION%,
"externalReferences":
[
null
],
"operations": "{\n function f1()\n {\n function f2()\n { }\n x := 2\n }\n}"
},
"children": [],
"id": 5,
"name": "InlineAssembly",
"src": "63:87:1"
}
],
"id": 6,
"name": "Block",
"src": "57:97:1"
}
],
"id": 7,
"name": "FunctionDefinition",
"src": "15:139:1"
}
],
"id": 8,
"name": "ContractDefinition",
"src": "0:156:1"
}
],
"id": 9,
"name": "SourceUnit",
"src": "0:157:1"
}

18
test/libsolidity/ASTJSON/assembly/switch.json
View File

@ -158,7 +158,23 @@
]
},
"evmVersion": %EVMVERSION%,
"externalReferences": [],
"externalReferences":
[
{
"declaration": 5,
"isOffset": false,
"isSlot": false,
"src": "141:1:1",
"valueSize": 18446744073709551615
},
{
"declaration": 5,
"isOffset": false,
"isSlot": false,
"src": "172:1:1",
"valueSize": 18446744073709551615
}
],
"id": 3,
"nodeType": "InlineAssembly",
"src": "52:138:1"

15
test/libsolidity/ASTJSON/assembly/switch_legacy.json
View File

@ -92,7 +92,20 @@
"evmVersion": %EVMVERSION%,
"externalReferences":
[
null
{
"declaration": 5,
"isOffset": false,
"isSlot": false,
"src": "141:1:1",
"valueSize": 18446744073709551615
},
{
"declaration": 5,
"isOffset": false,
"isSlot": false,
"src": "172:1:1",
"valueSize": 18446744073709551615
}
],
"operations": "{\n let f := 0\n switch calldatasize()\n case 0 { f := 1 }\n default { f := 2 }\n}"
},

12
test/libsolidity/syntaxTests/inlineAssembly/invalid/nested_function_local_access.sol Normal file
View File

@ -0,0 +1,12 @@
contract C {
function f() public pure returns (uint x) {
assembly {
function f1() {
function f2() { }
x := 2
}
}
}
}
// ----
// DeclarationError: (130-131): Cannot access local Solidity variables from inside an inline assembly function.