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#include "cps/CodeGen.h"
#include "cps/MemoryHandler.h"
#include "cps/TypeAST.h"
#include <climits>
#include <cstddef>
using namespace llvm;
using namespace cps;
bool CodeGen::typeNeedsConstruction(const std::string &TypeName) const {
if (findMethod(TypeName, "NEW")) return true;
const TypeInfo *Info = resolveType(TypeName);
if (Info && Info->asRecord()) {
for (const auto &[Name, Field] : Info->Record.Fields)
if (typeNeedsConstruction(Field.TypeName)) return true;
}
return false;
}
bool CodeGen::emitConstruct(const std::string &TypeName, Value *Addr,
const std::vector<std::unique_ptr<ExprAST>> &Args, int Line) {
SaveAndRestore<int> Location(DiagnosticLine, Line);
const TypeInfo *Info = resolveType(TypeName);
if (!Info) return false;
if (Info->asRecord()) {
for (const auto &[Name, Field] : Info->Record.Fields) {
if (!typeNeedsConstruction(Field.TypeName)) continue;
Value *FieldAddr = Builder->CreateStructGEP(Info->LLVMType, Addr, Field.Index);
if (!emitDefaultConstruct(Field.TypeName, FieldAddr, Line)) return false;
}
}
if (findMethod(TypeName, "NEW"))
return emitMethodCall(TypeName, Addr, "NEW", Args, Line) != nullptr;
if (!Args.empty()) {
reportError("Type %s has no constructor NEW but arguments were supplied", TypeName.c_str());
return false;
}
return true;
}
bool CodeGen::emitDefaultConstruct(const std::string &TypeName, Value *Addr, int Line) {
return emitConstruct(TypeName, Addr, {}, Line);
}
Value *CodeGen::symbolAddress(const SymbolInfo &Info) {
if (!Info.IsReference) return Info.Storage;
return Builder->CreateLoad(PointerType::getUnqual(*TheContext), Info.Storage, "object_address");
}
void CodeGen::emitAssignment(const LValueInfo &Target, ExprAST *Expr, const SymbolInfo *Symbol) {
const TypeInfo *Info = resolveType(Target.TypeName);
if (auto *New = dynamic_cast<NewExprAST*>(Expr)) {
SaveAndRestore<int> Location(DiagnosticLine, New->getLine());
const TypeInfo *Class = resolveType(New->getClassName());
if (!Class || !Class->IsClass) {
reportError("NEW requires a class type: %s", New->getClassName().c_str());
return;
}
if (!Info || !Info->sameType(Class)) {
reportError("NEW target must have type %s", Class->Name.c_str());
return;
}
Value *Size = Builder->CreateIntCast(Types->getSizeOfConstant(Class->LLVMType),
Type::getIntNTy(*TheContext, sizeof(std::size_t) * CHAR_BIT), false);
// Method-only classes have zero-sized LLVM structs but still need
// a non-null object address (MALLOC(0) deliberately returns null).
Size = Builder->CreateSelect(Builder->CreateICmpEQ(Size, ConstantInt::get(Size->getType(), 0)),
ConstantInt::get(Size->getType(), 1), Size);
Value *Object = Memory->emitAllocate(Size, New->getLine());
Builder->CreateStore(Types->getZeroValue(Class->Name), Object);
if (!emitConstruct(Class->Name, Object, New->getArgs(), New->getLine())) return;
if (Symbol && Symbol->IsReference) {
Builder->CreateStore(Object, Symbol->Storage);
} else {
Value *Val = Builder->CreateLoad(Class->LLVMType, Object);
Builder->CreateStore(Val, Target.Addr);
}
return;
}
Value *Val = emitCoercedExpr(Expr, Info);
if (Val) Builder->CreateStore(Val, Target.Addr);
}
bool CodeGen::typeNeedsDestruction(const std::string &TypeName) const {
if (findMethod(TypeName, "DELETE")) return true;
const TypeInfo *Info = resolveType(TypeName);
if (Info && Info->asRecord()) {
for (const auto &[Name, Field] : Info->Record.Fields)
if (typeNeedsDestruction(Field.TypeName)) return true;
}
return false;
}
bool CodeGen::emitDestroy(const std::string &TypeName, Value *Addr, int Line) {
SaveAndRestore<int> Location(DiagnosticLine, Line);
const TypeInfo *Info = resolveType(TypeName);
if (!Info) return false;
if (findMethod(TypeName, "DELETE") &&
!emitMethodCall(TypeName, Addr, "DELETE", {}, Line)) return false;
if (Info->asRecord()) {
for (auto It = Info->Record.Fields.rbegin(); It != Info->Record.Fields.rend(); ++It) {
const auto &Field = It->second;
if (!typeNeedsDestruction(Field.TypeName)) continue;
Value *FieldAddr = Builder->CreateStructGEP(Info->LLVMType, Addr, Field.Index);
if (!emitDestroy(Field.TypeName, FieldAddr, Line)) return false;
}
}
return true;
}
size_t CodeGen::registerStackObject(Value *Addr, const std::string &TypeName, int Line,
bool IsArray, bool IsCopy) {
if (!typeNeedsDestruction(TypeName)) return size_t(-1);
auto *F = Builder->GetInsertBlock()->getParent();
IRBuilder<> Entry(&F->getEntryBlock(), F->getEntryBlock().begin());
auto *Alive = Entry.CreateAlloca(Entry.getInt1Ty(), nullptr, "object_alive");
Entry.CreateStore(Entry.getFalse(), Alive);
AllocaInst *Count = nullptr;
if (IsArray) {
Count = Entry.CreateAlloca(Entry.getInt64Ty(), nullptr, "object_count");
Entry.CreateStore(Entry.getInt64(0), Count);
}
StackObjects.push_back({Addr, TypeName, Alive, Count, Line, IsCopy});
// This DECLARE can execute repeatedly, including after a backward loop edge.
emitStackObjectCleanup(StackObjects.back());
return StackObjects.size() - 1;
}
void CodeGen::activateStackObject(size_t Index, Value *Count) {
if (Index == size_t(-1)) return;
const auto &Object = StackObjects[Index];
if (Object.Count) Builder->CreateStore(Count, Object.Count);
Builder->CreateStore(Builder->getTrue(), Object.Alive);
}
void CodeGen::emitStackObjectCleanup(const StackObject &Object) {
auto *F = Builder->GetInsertBlock()->getParent();
auto *Destroy = BasicBlock::Create(*TheContext, "destroy_object", F);
auto *Done = BasicBlock::Create(*TheContext, "destroyed_object", F);
Builder->CreateCondBr(Builder->CreateLoad(Builder->getInt1Ty(), Object.Alive), Destroy, Done);
Builder->SetInsertPoint(Destroy);
// Clear before the user method: a throwing destructor must never run twice.
Builder->CreateStore(Builder->getFalse(), Object.Alive);
if (!Object.Count) {
emitDestroy(Object.TypeName, Object.Addr, Object.Line);
} else {
Value *Base = Builder->CreateLoad(PointerType::getUnqual(*TheContext), Object.Addr);
Value *Count = Builder->CreateLoad(Builder->getInt64Ty(), Object.Count);
auto *Preheader = Builder->GetInsertBlock();
auto *Loop = BasicBlock::Create(*TheContext, "destroy_elements", F);
auto *Body = BasicBlock::Create(*TheContext, "destroy_element", F);
Builder->CreateBr(Loop);
Builder->SetInsertPoint(Loop);
auto *Index = Builder->CreatePHI(Builder->getInt64Ty(), 2);
Index->addIncoming(Count, Preheader);
Builder->CreateCondBr(Builder->CreateICmpNE(Index, Builder->getInt64(0)), Body, Done);
Builder->SetInsertPoint(Body);
Value *Previous = Builder->CreateSub(Index, Builder->getInt64(1));
Value *Element = Builder->CreateGEP(resolveType(Object.TypeName)->LLVMType, Base, Previous);
emitDestroy(Object.TypeName, Element, Object.Line);
Index->addIncoming(Previous, Builder->GetInsertBlock());
Builder->CreateBr(Loop);
Builder->SetInsertPoint(Done);
return;
}
Builder->CreateBr(Done);
Builder->SetInsertPoint(Done);
}
void CodeGen::finishStackObjects(Function *F) {
IRBuilderBase::InsertPointGuard Guard(*Builder);
std::vector<Instruction *> Exits;
for (auto &BB : *F)
if (BB.hasTerminator() && isa<ReturnInst>(BB.getTerminator()))
Exits.push_back(BB.getTerminator());
for (auto *Exit : Exits) {
// Keep the original terminator in a continuation while cleanup builds branches.
auto *BB = Exit->getParent();
auto *Continuation = BB->splitBasicBlock(Exit->getIterator(), "after_destruction");
BB->getTerminator()->eraseFromParent();
Builder->SetInsertPoint(BB);
for (auto It = StackObjects.rbegin(); It != StackObjects.rend(); ++It)
emitStackObjectCleanup(*It);
Builder->CreateBr(Continuation);
}
}
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