Implement an indirect-goto optimization for goto *&&lbl and respect this
in the scope checker. With that done, turn an indirect goto into a
protected scope into a hard error; otherwise IR generation has to start
worrying about declarations not dominating their scopes, as exemplified
in PR8473.
If this really affects anyone, I can probably adjust this to only hard-error
on possible indirect gotos into VLA scopes rather than arbitrary scopes.
But we'll see how people cope with the aggressive change on the marginal
feature.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@117539 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Stmt.cpp b/lib/AST/Stmt.cpp
index 4f46b35..09d889e 100644
--- a/lib/AST/Stmt.cpp
+++ b/lib/AST/Stmt.cpp
@@ -669,8 +669,12 @@
Stmt::child_iterator GotoStmt::child_end() { return child_iterator(); }
// IndirectGotoStmt
-Expr* IndirectGotoStmt::getTarget() { return cast<Expr>(Target); }
-const Expr* IndirectGotoStmt::getTarget() const { return cast<Expr>(Target); }
+LabelStmt *IndirectGotoStmt::getConstantTarget() {
+ if (AddrLabelExpr *E =
+ dyn_cast<AddrLabelExpr>(getTarget()->IgnoreParenImpCasts()))
+ return E->getLabel();
+ return 0;
+}
Stmt::child_iterator IndirectGotoStmt::child_begin() { return &Target; }
Stmt::child_iterator IndirectGotoStmt::child_end() { return &Target+1; }
diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index 008c075..4de505a 100644
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -297,6 +297,11 @@
void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
+ if (const LabelStmt *Target = S.getConstantTarget()) {
+ EmitBranchThroughCleanup(getJumpDestForLabel(Target));
+ return;
+ }
+
// Ensure that we have an i8* for our PHI node.
llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()),
llvm::Type::getInt8PtrTy(VMContext),
diff --git a/lib/Sema/JumpDiagnostics.cpp b/lib/Sema/JumpDiagnostics.cpp
index b23f615..bbe7bd5 100644
--- a/lib/Sema/JumpDiagnostics.cpp
+++ b/lib/Sema/JumpDiagnostics.cpp
@@ -186,6 +186,17 @@
break;
case Stmt::IndirectGotoStmtClass:
+ // "goto *&&lbl;" is a special case which we treat as equivalent
+ // to a normal goto. In addition, we don't calculate scope in the
+ // operand (to avoid recording the address-of-label use), which
+ // works only because of the restricted set of expressions which
+ // we detect as constant targets.
+ if (cast<IndirectGotoStmt>(S)->getConstantTarget()) {
+ LabelAndGotoScopes[S] = ParentScope;
+ Jumps.push_back(S);
+ return;
+ }
+
LabelAndGotoScopes[S] = ParentScope;
IndirectJumps.push_back(cast<IndirectGotoStmt>(S));
break;
@@ -341,6 +352,14 @@
continue;
}
+ // We only get indirect gotos here when they have a constant target.
+ if (IndirectGotoStmt *IGS = dyn_cast<IndirectGotoStmt>(Jump)) {
+ LabelStmt *Target = IGS->getConstantTarget();
+ CheckJump(IGS, Target, IGS->getGotoLoc(),
+ diag::err_goto_into_protected_scope);
+ continue;
+ }
+
SwitchStmt *SS = cast<SwitchStmt>(Jump);
for (SwitchCase *SC = SS->getSwitchCaseList(); SC;
SC = SC->getNextSwitchCase()) {
@@ -497,7 +516,7 @@
unsigned TargetScope) {
assert(JumpScope != TargetScope);
- S.Diag(Jump->getGotoLoc(), diag::warn_indirect_goto_in_protected_scope);
+ S.Diag(Jump->getGotoLoc(), diag::err_indirect_goto_in_protected_scope);
S.Diag(Target->getIdentLoc(), diag::note_indirect_goto_target);
unsigned Common = GetDeepestCommonScope(JumpScope, TargetScope);