C++1y: support 'for', 'while', and 'do ... while' in constant expressions.
llvm-svn: 181181
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 5d153c4..14503f4 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -915,10 +915,14 @@
/// Evaluate an expression to see if it had side-effects, and discard its
/// result.
-static void EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
+/// \return \c true if the caller should keep evaluating.
+static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
APValue Scratch;
- if (!Evaluate(Scratch, Info, E))
+ if (!Evaluate(Scratch, Info, E)) {
Info.EvalStatus.HasSideEffects = true;
+ return Info.keepEvaluatingAfterFailure();
+ }
+ return true;
}
/// Should this call expression be treated as a string literal?
@@ -2457,7 +2461,11 @@
/// Hit a 'return' statement.
ESR_Returned,
/// Evaluation succeeded.
- ESR_Succeeded
+ ESR_Succeeded,
+ /// Hit a 'continue' statement.
+ ESR_Continue,
+ /// Hit a 'break' statement.
+ ESR_Break
};
}
@@ -2482,6 +2490,32 @@
return true;
}
+/// Evaluate a condition (either a variable declaration or an expression).
+static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl,
+ const Expr *Cond, bool &Result) {
+ if (CondDecl && !EvaluateDecl(Info, CondDecl))
+ return false;
+ return EvaluateAsBooleanCondition(Cond, Result, Info);
+}
+
+static EvalStmtResult EvaluateStmt(APValue &Result, EvalInfo &Info,
+ const Stmt *S);
+
+/// Evaluate the body of a loop, and translate the result as appropriate.
+static EvalStmtResult EvaluateLoopBody(APValue &Result, EvalInfo &Info,
+ const Stmt *Body) {
+ switch (EvalStmtResult ESR = EvaluateStmt(Result, Info, Body)) {
+ case ESR_Break:
+ return ESR_Succeeded;
+ case ESR_Succeeded:
+ case ESR_Continue:
+ return ESR_Continue;
+ case ESR_Failed:
+ case ESR_Returned:
+ return ESR;
+ }
+}
+
// Evaluate a statement.
static EvalStmtResult EvaluateStmt(APValue &Result, EvalInfo &Info,
const Stmt *S) {
@@ -2490,10 +2524,9 @@
switch (S->getStmtClass()) {
default:
if (const Expr *E = dyn_cast<Expr>(S)) {
- EvaluateIgnoredValue(Info, E);
// Don't bother evaluating beyond an expression-statement which couldn't
// be evaluated.
- if (Info.EvalStatus.HasSideEffects && !Info.keepEvaluatingAfterFailure())
+ if (!EvaluateIgnoredValue(Info, E))
return ESR_Failed;
return ESR_Succeeded;
}
@@ -2536,13 +2569,7 @@
// Evaluate the condition, as either a var decl or as an expression.
bool Cond;
- if (VarDecl *CondDecl = IS->getConditionVariable()) {
- if (!EvaluateDecl(Info, CondDecl))
- return ESR_Failed;
- if (!HandleConversionToBool(Info.CurrentCall->Temporaries[CondDecl],
- Cond))
- return ESR_Failed;
- } else if (!EvaluateAsBooleanCondition(IS->getCond(), Cond, Info))
+ if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), Cond))
return ESR_Failed;
if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) {
@@ -2552,6 +2579,68 @@
}
return ESR_Succeeded;
}
+
+ case Stmt::WhileStmtClass: {
+ const WhileStmt *WS = cast<WhileStmt>(S);
+ while (true) {
+ bool Continue;
+ if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(),
+ Continue))
+ return ESR_Failed;
+ if (!Continue)
+ break;
+
+ EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody());
+ if (ESR != ESR_Continue)
+ return ESR;
+ }
+ return ESR_Succeeded;
+ }
+
+ case Stmt::DoStmtClass: {
+ const DoStmt *DS = cast<DoStmt>(S);
+ bool Continue;
+ do {
+ EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody());
+ if (ESR != ESR_Continue)
+ return ESR;
+
+ if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info))
+ return ESR_Failed;
+ } while (Continue);
+ return ESR_Succeeded;
+ }
+
+ case Stmt::ForStmtClass: {
+ const ForStmt *FS = cast<ForStmt>(S);
+ if (FS->getInit()) {
+ EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
+ if (ESR != ESR_Succeeded)
+ return ESR;
+ }
+ while (true) {
+ bool Continue = true;
+ if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(),
+ FS->getCond(), Continue))
+ return ESR_Failed;
+ if (!Continue)
+ break;
+
+ EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody());
+ if (ESR != ESR_Continue)
+ return ESR;
+
+ if (FS->getInc() && !EvaluateIgnoredValue(Info, FS->getInc()))
+ return ESR_Failed;
+ }
+ return ESR_Succeeded;
+ }
+
+ case Stmt::ContinueStmtClass:
+ return ESR_Continue;
+
+ case Stmt::BreakStmtClass:
+ return ESR_Break;
}
}