void ScopeStack::popCleanups(CleanupCursor targetScope) {
assert(targetScope <= currentCleanupScope());
if (targetScope == currentCleanupScope()) {
return;
}
for (CleanupCursor i = currentCleanupScope(); i-- > targetScope;) {
// Any gotos that are still unresolved necessarily leave this scope.
// Thus, the cleanup needs to be executed.
for (const auto &gotoJump : currentUnresolvedGotos()) {
// Make the source resp. last cleanup branch to this one.
llvm::BasicBlock *tentative = gotoJump.tentativeTarget;
tentative->replaceAllUsesWith(cleanupScopes[i].beginBlock);
// And continue execution with the tentative target (we simply reuse
// it because there is no reason not to).
executeCleanup(irs, cleanupScopes[i], gotoJump.sourceBlock, tentative);
}
std::vector<GotoJump> &nextUnresolved =
(i == 0) ? topLevelUnresolvedGotos
: cleanupScopes[i - 1].unresolvedGotos;
nextUnresolved.insert(nextUnresolved.end(),
currentUnresolvedGotos().begin(),
currentUnresolvedGotos().end());
cleanupScopes.pop_back();
}
}
TryCatchFinallyScopes::~TryCatchFinallyScopes() {
assert(currentCleanupScope() == 0);
// If there are still unresolved gotos left, it means that they were either
// down or "sideways" (i.e. down another branch) of the tree of all
// cleanup scopes, both of which are not allowed in D.
if (!currentUnresolvedGotos().empty()) {
for (const auto &i : currentUnresolvedGotos()) {
error(i.sourceLoc, "`goto` into `try`/`finally` scope is not allowed");
}
fatal();
}
}
void ScopeStack::jumpToLabel(Loc loc, Identifier *labelName) {
// If we have already seen that label, branch to it, executing any cleanups
// as necessary.
auto it = labelTargets.find(labelName);
if (it != labelTargets.end()) {
runCleanups(it->second.cleanupScope, it->second.targetBlock);
return;
}
llvm::BasicBlock *target = llvm::BasicBlock::Create(
irs->context(), "goto.unresolved", irs->topfunc());
irs->ir->CreateBr(target);
currentUnresolvedGotos().emplace_back(loc, irs->scopebb(), target, labelName);
}
void TryCatchFinallyScopes::popCleanups(CleanupCursor targetScope) {
assert(targetScope <= currentCleanupScope());
if (targetScope == currentCleanupScope())
return;
for (CleanupCursor i = currentCleanupScope(); i-- > targetScope;) {
// Any gotos that are still unresolved necessarily leave this scope.
// Thus, the cleanup needs to be executed.
for (const auto &gotoJump : currentUnresolvedGotos()) {
// Replace all branches to the tentative target by branches to the cleanup
// and continue with the tentative target (we simply reuse it because
// there is no reason not to).
llvm::BasicBlock *tentative = gotoJump.tentativeTarget;
// 1) Replace all branches to the tentative target by branches to a
// temporary placeholder BB.
llvm::BasicBlock *dummy = irs.insertBB("");
tentative->replaceAllUsesWith(dummy);
// 2) We need a cleanup instance which continues execution with the
// tentative target.
auto startCleanup =
cleanupScopes[i].run(irs, gotoJump.sourceBlock, tentative);
// 3) Replace all branches to the placeholder BB by branches to the
// cleanup.
dummy->replaceAllUsesWith(startCleanup);
dummy->eraseFromParent();
}
Gotos &nextUnresolved = unresolvedGotosPerCleanupScope[i];
nextUnresolved.insert(nextUnresolved.end(),
currentUnresolvedGotos().begin(),
currentUnresolvedGotos().end());
cleanupScopes.pop_back();
unresolvedGotosPerCleanupScope.pop_back();
landingPadsPerCleanupScope.pop_back();
}
}
void TryCatchFinallyScopes::tryResolveGotos(Identifier *labelName,
llvm::BasicBlock *targetBlock) {
auto &unresolved = currentUnresolvedGotos();
size_t i = 0;
while (i < unresolved.size()) {
if (unresolved[i].targetLabel != labelName) {
++i;
continue;
}
unresolved[i].tentativeTarget->replaceAllUsesWith(targetBlock);
unresolved[i].tentativeTarget->eraseFromParent();
unresolved.erase(unresolved.begin() + i);
}
}
void ScopeStack::addLabelTarget(Identifier *labelName,
llvm::BasicBlock *targetBlock) {
labelTargets[labelName] = {targetBlock, currentCleanupScope(), nullptr};
// See whether any of the unresolved gotos target this label, and resolve
// those that do.
std::vector<GotoJump> &unresolved = currentUnresolvedGotos();
size_t i = 0;
while (i < unresolved.size()) {
if (unresolved[i].targetLabel != labelName) {
++i;
continue;
}
unresolved[i].tentativeTarget->replaceAllUsesWith(targetBlock);
unresolved[i].tentativeTarget->eraseFromParent();
unresolved.erase(unresolved.begin() + i);
}
}
void TryCatchFinallyScopes::registerUnresolvedGoto(Loc loc,
Identifier *labelName) {
llvm::BasicBlock *target = irs.insertBB("goto.unresolved");
irs.ir->CreateBr(target);
currentUnresolvedGotos().push_back({loc, irs.scopebb(), target, labelName});
}
