Value *AstVarExpr::Codegen(CodeGenerator *codegen) {
codegen->incrementVarCount();
Function *func = codegen->getCurrentFunction();
IAstExpression *expr = this->getAssignmentExpression();
Value *initialVal = nullptr;
AllocaInst *Alloca = nullptr;
if (expr == nullptr) { // variable declaration without an assignment, e.g: 'var x : int;'
if (this->InferredType->getIsArray()) { // type is an array.
Type *arrayType = this->InferredType->GetLLVMType(codegen);
Alloca = Helpers::CreateEntryBlockAlloca(codegen, func, this->Name.c_str(), arrayType);
}
else {
initialVal = Helpers::GetDefaultValue(codegen, this->InferredType);
Alloca = Helpers::CreateEntryBlockAlloca(codegen, func, this->Name.c_str(), this->InferredType->GetLLVMType(codegen));
}
}
else {
initialVal = expr->Codegen(codegen);
auto type = Helpers::GetLLVMTypeName(initialVal->getType());
Alloca = Helpers::CreateEntryBlockAlloca(codegen, func, this->Name, initialVal->getType());
}
if (initialVal != nullptr) {
codegen->getBuilder().CreateStore(initialVal, Alloca);
}
codegen->setNamedValue(this->Name, Alloca);
return initialVal == nullptr ? Alloca : initialVal;
}
// EmitScopeBlock - Emits a std::vector of ast::IAstExpr* expressions and returns their value
// in a std::vector<Value*>
std::vector<Value*> EmitScopeBlock(CodeGenerator *codegen, const std::vector<IAstExpression*> &block, bool stopAtFirstReturn, bool *stopped) {
unsigned varCount = codegen->getVarCount();
codegen->incrementNestDepth();
std::vector<Value*> vals;
for (unsigned i = 0, size = block.size(); i < size; ++i) {
IAstExpression *expr = block[i];
if (codegen->getBuilder().GetInsertBlock()->getTerminator() != nullptr) // stops multiple terminators per block.
{
Warning(expr->getPos(), "Unreachable code.");
continue;
}
Value *val = expr->Codegen(codegen);
if (val == nullptr) {
vals.clear();
goto RETURN;
}
vals.push_back(val);
if (stopAtFirstReturn && expr->getNodeType() == AstNodeType::node_return) {
if (stopped != nullptr) { *stopped = true; }
goto RETURN;
}
}
if (stopped != nullptr) { *stopped = false; }
RETURN:
// Pops all variables declared within this scope
codegen->popFromScopeStack(codegen->getVarCount() - varCount);
codegen->decrementNestDepth();
return vals;
}
Value *AstForExpr::Codegen(CodeGenerator *codegen) {
auto x = this;
Function *func = codegen->getCurrentFunction();
BasicBlock *outsideBB = codegen->getOutsideBlock();
BasicBlock *loopEndBB = BasicBlock::Create(codegen->getContext(), "loop_end", func, outsideBB);
BasicBlock *loopBodyBB = BasicBlock::Create(codegen->getContext(), "loop_body", func, loopEndBB);
codegen->setOutsideBlock(loopEndBB);
unsigned varCountBeforeInit = codegen->getVarCount(); // Keep track of the variables created within the for loop init.
// Emit the init.
for (unsigned i = 0, size = this->Init.size(); i < size; ++i) {
IAstExpression *expr = this->Init[i];
if (expr == nullptr || expr->Codegen(codegen) == nullptr) {
return Helpers::Error(this->getPos(), "Could not initialize 'for' loop.");
}
}
unsigned varCountAfterInit = codegen->getVarCount();
if (this->Condition == nullptr) { // Disallow for loop without condition.
return Helpers::Error(this->getPos(), "For loop must have a condition.");
}
Value *cond = this->Condition->Codegen(codegen);
if (!cond->getType()->isIntegerTy()) { // Condition isn't a possible boolean type.
return Helpers::Error(this->Condition->getPos(), "'for' condition not boolean");
}
Value *toBool = Helpers::ToBoolean(codegen, cond);
// Eval the bool and branch accordingly
codegen->getBuilder().CreateCondBr(toBool, loopBodyBB, loopEndBB);
// Emit the loop body.
codegen->getBuilder().SetInsertPoint(loopBodyBB);
Helpers::EmitScopeBlock(codegen, this->Body, true);
// Emit the afterthough
Helpers::EmitScopeBlock(codegen, this->Afterthought, true);
// Eval the condition, branch accordingly
cond = this->Condition->Codegen(codegen);
toBool = Helpers::ToBoolean(codegen, cond);
codegen->getBuilder().CreateCondBr(toBool, loopBodyBB, loopEndBB);
// Cleanup the variables created in the init.
codegen->popFromScopeStack(varCountAfterInit - varCountBeforeInit);
// Set insert point to the loop and and cleanup.
codegen->getBuilder().SetInsertPoint(loopEndBB);
loopBodyBB = codegen->getBuilder().GetInsertBlock();
loopEndBB = codegen->getBuilder().GetInsertBlock();
codegen->setOutsideBlock(outsideBB);
return loopEndBB;
}
