Merge pull request #2319 from ethereum/virtualBlocks

Introduce virtual blocks for function arguments.

5 files changed, 28 insertions, 21 deletions

diff --git a/libsolidity/inlineasm/AsmAnalysis.cpp b/libsolidity/inlineasm/AsmAnalysis.cpp
index eeb7d0a6..9f512f87 100644
--- a/libsolidity/inlineasm/AsmAnalysis.cpp
+++ b/libsolidity/inlineasm/AsmAnalysis.cpp
@@ -46,7 +46,7 @@ set<string> const builtinTypes{"bool", "u8", "s8", "u32", "s32", "u64", "s64", "
 
 bool AsmAnalyzer::analyze(Block const& _block)
 {
-	if (!(ScopeFiller(m_info.scopes, m_errors))(_block))
+	if (!(ScopeFiller(m_info, m_errors))(_block))
 		return false;
 
 	return (*this)(_block);
@@ -206,16 +206,17 @@ bool AsmAnalyzer::operator()(assembly::VariableDeclaration const& _varDecl)
 
 bool AsmAnalyzer::operator()(assembly::FunctionDefinition const& _funDef)
 {
-	Scope& bodyScope = scope(&_funDef.body);
+	Block const* virtualBlock = m_info.virtualBlocks.at(&_funDef).get();
+	solAssert(virtualBlock, "");
+	Scope& varScope = scope(virtualBlock);
 	for (auto const& var: _funDef.arguments + _funDef.returns)
 	{
 		expectValidType(var.type, var.location);
-		boost::get<Scope::Variable>(bodyScope.identifiers.at(var.name)).active = true;
+		boost::get<Scope::Variable>(varScope.identifiers.at(var.name)).active = true;
 	}
 
 	int const stackHeight = m_stackHeight;
 	m_stackHeight = _funDef.arguments.size() + _funDef.returns.size();
-	m_virtualVariablesInNextBlock = m_stackHeight;
 
 	bool success = (*this)(_funDef.body);
 
@@ -337,10 +338,10 @@ bool AsmAnalyzer::operator()(Switch const& _switch)
 bool AsmAnalyzer::operator()(Block const& _block)
 {
 	bool success = true;
+	auto previousScope = m_currentScope;
 	m_currentScope = &scope(&_block);
 
-	int const initialStackHeight = m_stackHeight - m_virtualVariablesInNextBlock;
-	m_virtualVariablesInNextBlock = 0;
+	int const initialStackHeight = m_stackHeight;
 
 	for (auto const& s: _block.statements)
 		if (!boost::apply_visitor(*this, s))
@@ -366,8 +367,8 @@ bool AsmAnalyzer::operator()(Block const& _block)
 		success = false;
 	}
 
-	m_currentScope = m_currentScope->superScope;
 	m_info.stackHeightInfo[&_block] = m_stackHeight;
+	m_currentScope = previousScope;
 	return success;
 }
 
diff --git a/libsolidity/inlineasm/AsmAnalysis.h b/libsolidity/inlineasm/AsmAnalysis.h
index 87d41e11..14b18c4a 100644
--- a/libsolidity/inlineasm/AsmAnalysis.h
+++ b/libsolidity/inlineasm/AsmAnalysis.h
@@ -91,10 +91,6 @@ private:
 	Scope& scope(assembly::Block const* _block);
 	void expectValidType(std::string const& type, SourceLocation const& _location);
 
-	/// This is used when we enter the body of a function definition. There, the parameters
-	/// and return parameters appear as variables which are already on the stack before
-	/// we enter the block.
-	int m_virtualVariablesInNextBlock = 0;
 	int m_stackHeight = 0;
 	julia::ExternalIdentifierAccess::Resolver const& m_resolver;
 	Scope* m_currentScope = nullptr;
diff --git a/libsolidity/inlineasm/AsmAnalysisInfo.h b/libsolidity/inlineasm/AsmAnalysisInfo.h
index 18382db0..78c1fbe0 100644
--- a/libsolidity/inlineasm/AsmAnalysisInfo.h
+++ b/libsolidity/inlineasm/AsmAnalysisInfo.h
@@ -24,6 +24,7 @@
 
 #include <map>
 #include <memory>
+#include <vector>
 
 namespace dev
 {
@@ -55,6 +56,8 @@ struct AsmAnalysisInfo
 	using Scopes = std::map<assembly::Block const*, std::shared_ptr<Scope>>;
 	Scopes scopes;
 	StackHeightInfo stackHeightInfo;
+	/// Virtual blocks which will be used for scopes for function arguments and return values.
+	std::map<FunctionDefinition const*, std::shared_ptr<assembly::Block const>> virtualBlocks;
 };
 
 }
diff --git a/libsolidity/inlineasm/AsmScopeFiller.cpp b/libsolidity/inlineasm/AsmScopeFiller.cpp
index 7eb6a9ed..3fade842 100644
--- a/libsolidity/inlineasm/AsmScopeFiller.cpp
+++ b/libsolidity/inlineasm/AsmScopeFiller.cpp
@@ -22,6 +22,7 @@
 
 #include <libsolidity/inlineasm/AsmData.h>
 #include <libsolidity/inlineasm/AsmScope.h>
+#include <libsolidity/inlineasm/AsmAnalysisInfo.h>
 
 #include <libsolidity/interface/Exceptions.h>
 #include <libsolidity/interface/Utils.h>
@@ -36,8 +37,8 @@ using namespace dev;
 using namespace dev::solidity;
 using namespace dev::solidity::assembly;
 
-ScopeFiller::ScopeFiller(ScopeFiller::Scopes& _scopes, ErrorList& _errors):
-	m_scopes(_scopes), m_errors(_errors)
+ScopeFiller::ScopeFiller(AsmAnalysisInfo& _info, ErrorList& _errors):
+	m_info(_info), m_errors(_errors)
 {
 	m_currentScope = &scope(nullptr);
 }
@@ -84,16 +85,22 @@ bool ScopeFiller::operator()(assembly::FunctionDefinition const& _funDef)
 		));
 		success = false;
 	}
-	Scope& body = scope(&_funDef.body);
-	body.superScope = m_currentScope;
-	body.functionScope = true;
+
+	auto virtualBlock = m_info.virtualBlocks[&_funDef] = make_shared<Block>();
+	Scope& varScope = scope(virtualBlock.get());
+	varScope.superScope = m_currentScope;
+	m_currentScope = &varScope;
+	varScope.functionScope = true;
 	for (auto const& var: _funDef.arguments + _funDef.returns)
-		if (!registerVariable(var, _funDef.location, body))
+		if (!registerVariable(var, _funDef.location, varScope))
 			success = false;
 
 	if (!(*this)(_funDef.body))
 		success = false;
 
+	solAssert(m_currentScope == &varScope, "");
+	m_currentScope = m_currentScope->superScope;
+
 	return success;
 }
 
@@ -137,7 +144,7 @@ bool ScopeFiller::registerVariable(TypedName const& _name, SourceLocation const&
 
 Scope& ScopeFiller::scope(Block const* _block)
 {
-	auto& scope = m_scopes[_block];
+	auto& scope = m_info.scopes[_block];
 	if (!scope)
 		scope = make_shared<Scope>();
 	return *scope;
diff --git a/libsolidity/inlineasm/AsmScopeFiller.h b/libsolidity/inlineasm/AsmScopeFiller.h
index c7179b3b..42e80141 100644
--- a/libsolidity/inlineasm/AsmScopeFiller.h
+++ b/libsolidity/inlineasm/AsmScopeFiller.h
@@ -49,6 +49,7 @@ struct FunctionCall;
 struct Switch;
 
 struct Scope;
+struct AsmAnalysisInfo;
 
 /**
  * Fills scopes with identifiers and checks for name clashes.
@@ -57,8 +58,7 @@ struct Scope;
 class ScopeFiller: public boost::static_visitor<bool>
 {
 public:
-	using Scopes = std::map<assembly::Block const*, std::shared_ptr<Scope>>;
-	ScopeFiller(Scopes& _scopes, ErrorList& _errors);
+	ScopeFiller(AsmAnalysisInfo& _info, ErrorList& _errors);
 
 	bool operator()(assembly::Instruction const&) { return true; }
 	bool operator()(assembly::Literal const&) { return true; }
@@ -83,7 +83,7 @@ private:
 	Scope& scope(assembly::Block const* _block);
 
 	Scope* m_currentScope = nullptr;
-	Scopes& m_scopes;
+	AsmAnalysisInfo& m_info;
 	ErrorList& m_errors;
 };