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Fix the two known limits: adding map keys while looping over the map is a runtime error; temporaries held by an expression are freed when try / or-blocks leave early. err usable after or, inner err shadows outer.

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Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
This commit is contained in:
Nexoniarz 2026-10-09 01:26:53 +02:00
commit 393327b353
9 changed files with 228 additions and 17 deletions
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64
src/codegen.cpp
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@ -296,6 +296,21 @@ void Codegen::define(Fn &fn) {
void Codegen::pushScope() { scopes.emplace_back(); }
void Codegen::hold(const Value_ &v) {
if (v.fresh && v.v && !isa<Constant>(v.v) && owning(v.type)) pending.push_back({v.v, v.type, false});
}
void Codegen::holdAddr(Value *addr, const FType &t) {
if (owning(t)) pending.push_back({addr, t, true});
}
void Codegen::dropPending(size_t downTo) {
for (size_t i = pending.size(); i-- > downTo;) {
if (pending[i].isAddr) dropAt(pending[i].v, pending[i].type);
else dropValue(pending[i].v, pending[i].type);
}
}
void Codegen::popScope() {
if (!terminated()) emitScopeCleanups(scopes.size() - 1);
scopes.pop_back();
@ -352,7 +367,8 @@ Var *Codegen::lookup(const std::string &name) {
Var &Codegen::addVar(Pos p, const std::string &name, const FType &t, Value *init, bool owned, bool readonly,
unsigned argNo) {
if (lookup(name)) failAt(p.file, p.line, p.col, "a variable named '" + name + "' already exists here");
// `err` of an inner `or` hides the outer one: f() or g() or err
if (lookup(name) && name != "err") failAt(p.file, p.line, p.col, "a variable named '" + name + "' already exists here");
ModuleScope &m = modules[curModule];
if (m.fns.count(name)) failAt(p.file, p.line, p.col, "'" + name + "' is already the name of a function");
if (m.imports.count(name)) failAt(p.file, p.line, p.col, "'" + name + "' is already the name of an imported module");
@ -427,6 +443,7 @@ void Codegen::jump(bool isBreak, Pos p) {
if (inDefer) failAt(p.file, p.line, p.col, std::string(word) + " can't be used inside defer");
if (loops.empty()) failAt(p.file, p.line, p.col, std::string(word) + " can only be used inside a loop");
Loop l = loops.back();
dropPending(l.pendingDepth);
emitCleanups(l.scopeDepth);
b.CreateBr(isBreak ? l.breakTo : l.continueTo);
}
@ -466,6 +483,8 @@ void Codegen::assign(const AssignStmt &s) {
if (Var *var = lookup(root)) { want = var->type; known = true; }
}
v = known ? exprWant(*s.value, want) : expr(*s.value);
Held held(*this);
hold(v); // while the target is computed (a[try f()] = ...)
Place dst = place(*s.target, true);
v = coerce(v, dst.type, s.value->pos, what);
Value *nv = own(v);
@ -481,6 +500,8 @@ void Codegen::assign(const AssignStmt &s) {
BinOp op = s.op == '+' ? BinOp::Add : s.op == '-' ? BinOp::Sub : s.op == '*' ? BinOp::Mul
: s.op == '/' ? BinOp::Div : BinOp::Mod;
Value_ rhs = expr(*s.value);
Held held(*this);
hold(rhs);
Place dst = place(*s.target, true);
Value_ cur{b.CreateLoad(ty(dst.type), dst.addr), dst.type};
Value_ v = coerce(arith(op, cur, rhs, s.pos), dst.type, s.pos, what);
@ -538,7 +559,7 @@ void Codegen::whileStmt(const WhileStmt &s) {
else b.CreateCondBr(cond, body, end);
b.SetInsertPoint(body);
loops.push_back({condBB, end, scopes.size()});
loops.push_back({condBB, end, scopes.size(), pending.size()});
block(*s.body);
loops.pop_back();
if (!terminated()) b.CreateBr(condBB);
@ -564,7 +585,7 @@ void Codegen::forStmt(const ForStmt &s) {
b.CreateCondBr(b.CreateICmpSLT(b.CreateLoad(b.getInt64Ty(), i), to), body, end);
b.SetInsertPoint(body);
loops.push_back({step, end, scopes.size()});
loops.push_back({step, end, scopes.size(), pending.size()});
block(*s.body);
loops.pop_back();
if (!terminated()) b.CreateBr(step);
@ -600,10 +621,20 @@ void Codegen::forEachStmt(const ForEachStmt &s) {
bool copyKV = live && mutates(rootVar(*s.list), *s.body);
Value *i = slot(FType::I64, "$i");
b.CreateStore(b.getInt64(0), i);
// adding keys inside the loop could reorder the entries: that stops the program (removing is fine)
Value *adds = live ? b.CreateLoad(b.getInt64Ty(), b.CreateStructGEP(MT, addr, 6)) : nullptr;
BasicBlock *condBB = newBlock("map.cond"), *check = newBlock("map.check"), *body = newBlock("map.body"),
*step = newBlock("map.step"), *end = newBlock("map.end");
b.CreateBr(condBB);
b.SetInsertPoint(condBB);
if (adds && mutates(rootVar(*s.list), *s.body)) {
BasicBlock *changed = newBlock("map.changed"), *same = newBlock("map.same");
b.CreateCondBr(b.CreateICmpNE(b.CreateLoad(b.getInt64Ty(), b.CreateStructGEP(MT, addr, 6)), adds), changed, same);
b.SetInsertPoint(changed);
b.CreateCall(rt("finch_map_changed"), {fileName(s.pos), b.getInt64(s.pos.line)});
b.CreateUnreachable();
b.SetInsertPoint(same);
}
Value *iv = b.CreateLoad(b.getInt64Ty(), i);
b.CreateCondBr(b.CreateICmpSLT(iv, b.CreateLoad(b.getInt64Ty(), b.CreateStructGEP(MT, addr, 2))), check, end);
b.SetInsertPoint(check);
@ -611,7 +642,7 @@ void Codegen::forEachStmt(const ForEachStmt &s) {
Value *hash = b.CreateLoad(b.getInt64Ty(), b.CreateStructGEP(ET, entry, 0));
b.CreateCondBr(b.CreateICmpEQ(hash, b.getInt64(0)), step, body); // a removed entry
b.SetInsertPoint(body);
loops.push_back({step, end, scopes.size()});
loops.push_back({step, end, scopes.size(), pending.size()});
pushScope();
std::string why = " can't be changed (to change the map, use m[key] = ...)";
Value *kv = b.CreateLoad(ty(kt), b.CreateStructGEP(ET, entry, 1));
@ -662,7 +693,7 @@ void Codegen::forEachStmt(const ForEachStmt &s) {
elemAddr = b.CreateInBoundsGEP(ty(et), data, iv);
}
Value *elem = b.CreateLoad(ty(et), elemAddr);
loops.push_back({step, end, scopes.size()});
loops.push_back({step, end, scopes.size(), pending.size()});
pushScope();
std::string elemVar = s.var;
Pos elemPos = s.varPos;
@ -718,6 +749,7 @@ void Codegen::returnStmt(const ReturnStmt &s) {
if (std::string(bd.name) == "error") note(c.pos, 5, "```finch\n" + std::string(bd.signature) + "\n```\n" + bd.doc);
checkArgs(c.args, c.argNames, 1, c.pos, "error");
Value *msg = own(coerce(expr(*c.args[0]), FType::Str, c.args[0]->pos, "the error message"));
dropPending(0);
emitCleanups(0);
retError(msg);
return;
@ -725,6 +757,7 @@ void Codegen::returnStmt(const ReturnStmt &s) {
if (curFn->ret.kind == FType::Void) {
if (s.value)
failAt(s.value->pos.file, s.value->pos.line, s.value->pos.col, "'" + d.name + "' doesn't return a value (it has no '-> type')");
dropPending(0);
emitCleanups(0);
retValue(nullptr);
return;
@ -740,6 +773,7 @@ void Codegen::returnStmt(const ReturnStmt &s) {
if (it->second.owned && it->second.type == curFn->ret) {
Value *v = b.CreateLoad(ty(it->second.type), it->second.slot);
it->second.moved = true;
dropPending(0);
emitCleanups(0);
scopes[idx].vars[name].moved = false;
retValue(v);
@ -750,6 +784,7 @@ void Codegen::returnStmt(const ReturnStmt &s) {
}
Value_ v = coerce(exprWant(*s.value, curFn->ret), curFn->ret, s.value->pos, "the returned value");
Value *out = own(v);
dropPending(0);
emitCleanups(0);
retValue(out);
}
@ -889,6 +924,7 @@ Value_ Codegen::tryExpr(const TryExpr &t) {
BasicBlock *bad = newBlock("try.failed"), *ok = newBlock("try.ok");
b.CreateCondBr(failed, bad, ok);
b.SetInsertPoint(bad);
dropPending(0); // what the expressions around this `try` were holding
emitCleanups(0);
retError(msg);
b.SetInsertPoint(ok);
@ -927,8 +963,10 @@ Value_ Codegen::orElse(const OrElseExpr &e, bool discard) {
Pos fp = e.fallback->pos;
if (v.type.kind == FType::Void)
failAt(fp.file, fp.line, fp.col, "this call gives back no value, so there is nothing to replace; handle the failure with or { ... }");
dropValue(msg, FType::Str);
pushScope(); // the fallback can use the message too: f(x) or err
addVar(fp, "err", FType::Str, msg, true);
Value *fv = own(coerce(exprWant(*e.fallback, v.type), v.type, fp, "the value after 'or'"));
popScope();
BasicBlock *badEnd = b.GetInsertBlock();
BasicBlock *join = newBlock("or.end");
b.CreateBr(join);
@ -1126,6 +1164,8 @@ LRef Codegen::index(const IndexExpr &e, bool forWrite) {
Pos p = e.pos;
LRef obj = ref(*e.obj, forWrite);
FType t = obj.isPlace ? obj.pl.type : obj.val.type;
Held held(*this);
if (!obj.isPlace) hold(obj.val); // while the index is computed
if (t.kind == FType::Map) return mapIndex(e, obj, t, forWrite);
Value *i = coerce(expr(*e.index), FType::I64, e.index->pos, "an index").v;
@ -1180,6 +1220,7 @@ Value_ Codegen::arrayLit(const ArrayLitExpr &a, const FType *want) {
if (allNum && anyFloat) et = FType::F64;
}
std::vector<Value *> vals;
Held held(*this);
for (size_t k = 0; k < a.elems.size(); k++) {
Value_ v = et.kind == FType::Void ? exprWant(*a.elems[k], et) : exprWant(*a.elems[k], et);
if (et.kind == FType::Void) {
@ -1189,6 +1230,7 @@ Value_ Codegen::arrayLit(const ArrayLitExpr &a, const FType *want) {
}
v = coerce(v, et, a.elems[k]->pos, "every element of this array");
vals.push_back(own(v));
hold({vals.back(), et, false, true});
}
FType at = FType::arrayOf(et);
Value *n = b.getInt64(vals.size());
@ -1404,11 +1446,17 @@ Value_ Codegen::binary(const BinaryExpr &e) {
case BinOp::Greater:
case BinOp::GreaterEq: {
Value_ l = expr(*e.lhs);
return compare(e.op, l, expr(*e.rhs), e.pos);
Held held(*this);
hold(l);
Value_ r = expr(*e.rhs);
return compare(e.op, l, r, e.pos);
}
default: {
Value_ l = expr(*e.lhs);
return arith(e.op, l, expr(*e.rhs), e.pos);
Held held(*this);
hold(l);
Value_ r = expr(*e.rhs);
return arith(e.op, l, r, e.pos);
}
}
}