When evaluating integer expressions include a check for sub-expressions
depth and error if we exceed a max value, to make sure we avoid a stack overflow.
This is a hacky temporary fix. rdar://10913206.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151585 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 44e4186..31750ea 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -44,6 +44,7 @@
#include "clang/Basic/Builtins.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SaveAndRestore.h"
#include <cstring>
#include <functional>
@@ -445,13 +446,18 @@
/// are suppressed.
bool CheckingPotentialConstantExpression;
+ /// \brief Stack depth of IntExprEvaluator.
+ /// We check this against a maximum value to avoid stack overflow, see
+ /// test case in test/Sema/many-logical-ops.c.
+ // FIXME: This is a hack; handle properly unlimited logical ops.
+ unsigned IntExprEvaluatorDepth;
EvalInfo(const ASTContext &C, Expr::EvalStatus &S)
: Ctx(const_cast<ASTContext&>(C)), EvalStatus(S), CurrentCall(0),
CallStackDepth(0), NextCallIndex(1),
BottomFrame(*this, SourceLocation(), 0, 0, 0),
EvaluatingDecl(0), EvaluatingDeclValue(0), HasActiveDiagnostic(false),
- CheckingPotentialConstantExpression(false) {}
+ CheckingPotentialConstantExpression(false), IntExprEvaluatorDepth(0) {}
const CCValue *getOpaqueValue(const OpaqueValueExpr *e) const {
MapTy::const_iterator i = OpaqueValues.find(e);
@@ -4067,6 +4073,20 @@
bool ZeroInitialization(const Expr *E) { return Success(0, E); }
+ // FIXME: See EvalInfo::IntExprEvaluatorDepth.
+ bool Visit(const Expr *E) {
+ SaveAndRestore<unsigned> Depth(Info.IntExprEvaluatorDepth,
+ Info.IntExprEvaluatorDepth+1);
+ const unsigned MaxDepth = 512;
+ if (Depth.get() > MaxDepth) {
+ Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
+ diag::err_intexpr_depth_limit_exceeded);
+ return false;
+ }
+
+ return ExprEvaluatorBaseTy::Visit(E);
+ }
+
//===--------------------------------------------------------------------===//
// Visitor Methods
//===--------------------------------------------------------------------===//