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Added implicit scope for if/else, while and do/while statements in ZScript

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Scope is added only for variable or constant definition so it will no longer leak to outer scope
https://forum.zdoom.org/viewtopic.php?t=57848
This commit is contained in:
alexey.lysiuk 2017-11-02 15:51:13 +02:00
parent 587f6f0f91
commit 57de598e48
2 changed files with 47 additions and 3 deletions
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49
src/scripting/zscript/zcc_compile.cpp
View file

@ -3495,7 +3495,9 @@ FxExpression *ZCCCompiler::ConvertNode(ZCC_TreeNode *ast)
case AST_IfStmt:
{
auto iff = static_cast<ZCC_IfStmt *>(ast);
return new FxIfStatement(ConvertNode(iff->Condition), ConvertNode(iff->TruePath), ConvertNode(iff->FalsePath), *ast);
FxExpression *const truePath = ConvertImplicitScopeNode(ast, iff->TruePath);
FxExpression *const falsePath = ConvertImplicitScopeNode(ast, iff->FalsePath);
return new FxIfStatement(ConvertNode(iff->Condition), truePath, falsePath, *ast);
}
case AST_IterationStmt:
@ -3504,7 +3506,8 @@ FxExpression *ZCCCompiler::ConvertNode(ZCC_TreeNode *ast)
if (iter->CheckAt == ZCC_IterationStmt::End)
{
assert(iter->LoopBumper == nullptr);
return new FxDoWhileLoop(ConvertNode(iter->LoopCondition), ConvertNode(iter->LoopStatement), *ast);
FxExpression *const loop = ConvertImplicitScopeNode(ast, iter->LoopStatement);
return new FxDoWhileLoop(ConvertNode(iter->LoopCondition), loop, *ast);
}
else if (iter->LoopBumper != nullptr)
{
@ -3520,7 +3523,8 @@ FxExpression *ZCCCompiler::ConvertNode(ZCC_TreeNode *ast)
}
else
{
return new FxWhileLoop(ConvertNode(iter->LoopCondition), ConvertNode(iter->LoopStatement), *ast);
FxExpression *const loop = ConvertImplicitScopeNode(ast, iter->LoopStatement);
return new FxWhileLoop(ConvertNode(iter->LoopCondition), loop, *ast);
}
}
@ -3584,6 +3588,45 @@ FxExpression *ZCCCompiler::ConvertNode(ZCC_TreeNode *ast)
return nullptr;
}
//==========================================================================
//
// Wrapper around ConvertNode() that adds a scope (a compound statement)
// when needed to avoid leaking of variable or contant to an outer scope:
//
// if (true) int i; else bool b[1];
// while (false) readonly<Actor> a;
// do static const float f[] = {0}; while (false);
//
// Accessing such variables outside of their statements is now an error
//
//==========================================================================
FxExpression *ZCCCompiler::ConvertImplicitScopeNode(ZCC_TreeNode *node, ZCC_Statement *nested)
{
assert(nullptr != node);
if (nullptr == nested)
{
return nullptr;
}
FxExpression *nestedExpr = ConvertNode(nested);
assert(nullptr != nestedExpr);
const EZCCTreeNodeType nestedType = nested->NodeType;
const bool needScope = AST_LocalVarStmt == nestedType || AST_StaticArrayStatement == nestedType;
if (needScope)
{
FxCompoundStatement *implicitCompound = new FxCompoundStatement(*node);
implicitCompound->Add(nestedExpr);
nestedExpr = implicitCompound;
}
return nestedExpr;
}
FArgumentList &ZCCCompiler::ConvertNodeList(FArgumentList &args, ZCC_TreeNode *head)
{

1
src/scripting/zscript/zcc_compile.h
View file

@ -145,6 +145,7 @@ private:
FxExpression *ConvertAST(PContainerType *cclass, ZCC_TreeNode *ast);
FxExpression *ConvertNode(ZCC_TreeNode *node);
FxExpression *ConvertImplicitScopeNode(ZCC_TreeNode *node, ZCC_Statement *nested);
FArgumentList &ConvertNodeList(FArgumentList &, ZCC_TreeNode *head);
DObject *Outer;