Add some helper methods that will be used in my next patch.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126596 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index ca47870..999788f 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -387,9 +387,12 @@
// If this is a label, we have to emit the code, consider something like:
// if (0) { ... foo: bar(); } goto foo;
+ //
+ // TODO: If anyone cared, we could track __label__'s, since we know that you
+ // can't jump to one from outside their declared region.
if (isa<LabelStmt>(S))
return true;
-
+
// If this is a case/default statement, and we haven't seen a switch, we have
// to emit the code.
if (isa<SwitchCase>(S) && !IgnoreCaseStmts)
@@ -407,27 +410,62 @@
return false;
}
+/// containsBreak - Return true if the statement contains a break out of it.
+/// If the statement (recursively) contains a switch or loop with a break
+/// inside of it, this is fine.
+bool CodeGenFunction::containsBreak(const Stmt *S) {
+ // Null statement, not a label!
+ if (S == 0) return false;
+
+ // If this is a switch or loop that defines its own break scope, then we can
+ // include it and anything inside of it.
+ if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) || isa<DoStmt>(S) ||
+ isa<ForStmt>(S))
+ return true;
+
+ // Scan subexpressions for verboten breaks.
+ for (Stmt::const_child_range I = S->children(); I; ++I)
+ if (containsBreak(*I))
+ return true;
+
+ return false;
+}
+
/// ConstantFoldsToSimpleInteger - If the specified expression does not fold
/// to a constant, or if it does but contains a label, return false. If it
/// constant folds return true and set the boolean result in Result.
bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond,
bool &ResultBool) {
+ llvm::APInt ResultInt;
+ if (!ConstantFoldsToSimpleInteger(Cond, ResultInt))
+ return false;
+
+ ResultBool = ResultInt.getBoolValue();
+ return true;
+}
+
+/// ConstantFoldsToSimpleInteger - If the specified expression does not fold
+/// to a constant, or if it does but contains a label, return false. If it
+/// constant folds return true and set the folded value.
+bool CodeGenFunction::
+ConstantFoldsToSimpleInteger(const Expr *Cond, llvm::APInt &ResultInt) {
// FIXME: Rename and handle conversion of other evaluatable things
// to bool.
Expr::EvalResult Result;
if (!Cond->Evaluate(Result, getContext()) || !Result.Val.isInt() ||
Result.HasSideEffects)
return false; // Not foldable, not integer or not fully evaluatable.
-
+
if (CodeGenFunction::ContainsLabel(Cond))
return false; // Contains a label.
-
- ResultBool = Result.Val.getInt().getBoolValue();
+
+ ResultInt = Result.Val.getInt();
return true;
}
+
/// EmitBranchOnBoolExpr - Emit a branch on a boolean condition (e.g. for an if
/// statement) to the specified blocks. Based on the condition, this might try
/// to simplify the codegen of the conditional based on the branch.