Add utility to evaluate lvalues which are an offset relative to a stack
location. Patch by Enea Zaffanella.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@81672 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/AST/Expr.h b/include/clang/AST/Expr.h
index 14e5972..81aecf7 100644
--- a/include/clang/AST/Expr.h
+++ b/include/clang/AST/Expr.h
@@ -248,9 +248,14 @@
/// must be called on an expression that constant folds to an integer.
llvm::APSInt EvaluateAsInt(ASTContext &Ctx) const;
- /// EvaluateAsLValue - Evaluate an expression to see if it's a valid LValue.
+ /// EvaluateAsLValue - Evaluate an expression to see if it's a lvalue
+ /// with link time known address.
bool EvaluateAsLValue(EvalResult &Result, ASTContext &Ctx) const;
+ /// EvaluateAsAnyLValue - The same as EvaluateAsLValue, except that it
+ /// also succeeds on stack based, immutable address lvalues.
+ bool EvaluateAsAnyLValue(EvalResult &Result, ASTContext &Ctx) const;
+
/// isNullPointerConstant - C99 6.3.2.3p3 - Return true if this is either an
/// integer constant expression with the value zero, or if this is one that is
/// cast to void*.
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 4494896..8f5ff72 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -46,8 +46,12 @@
/// EvalResult - Contains information about the evaluation.
Expr::EvalResult &EvalResult;
- EvalInfo(ASTContext &ctx, Expr::EvalResult& evalresult) : Ctx(ctx),
- EvalResult(evalresult) {}
+ /// AnyLValue - Stack based LValue results are not discarded.
+ bool AnyLValue;
+
+ EvalInfo(ASTContext &ctx, Expr::EvalResult& evalresult,
+ bool anylvalue = false)
+ : Ctx(ctx), EvalResult(evalresult), AnyLValue(anylvalue) {}
};
@@ -189,7 +193,7 @@
if (isa<FunctionDecl>(E->getDecl())) {
return APValue(E, 0);
} else if (VarDecl* VD = dyn_cast<VarDecl>(E->getDecl())) {
- if (!VD->hasGlobalStorage())
+ if (!Info.AnyLValue && !VD->hasGlobalStorage())
return APValue();
if (!VD->getType()->isReferenceType())
return APValue(E, 0);
@@ -209,9 +213,9 @@
}
APValue LValueExprEvaluator::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
- if (E->isFileScope())
- return APValue(E, 0);
- return APValue();
+ if (!Info.AnyLValue && !E->isFileScope())
+ return APValue();
+ return APValue(E, 0);
}
APValue LValueExprEvaluator::VisitMemberExpr(MemberExpr *E) {
@@ -1786,6 +1790,12 @@
return EvaluateLValue(this, Result.Val, Info) && !Result.HasSideEffects;
}
+bool Expr::EvaluateAsAnyLValue(EvalResult &Result, ASTContext &Ctx) const {
+ EvalInfo Info(Ctx, Result, true);
+
+ return EvaluateLValue(this, Result.Val, Info) && !Result.HasSideEffects;
+}
+
/// isEvaluatable - Call Evaluate to see if this expression can be constant
/// folded, but discard the result.
bool Expr::isEvaluatable(ASTContext &Ctx) const {