[PATCH] D131874: [Clang] Tighten restrictions on enum out of range diagnostic to avoid constant initialization
Shafik Yaghmour via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Wed Aug 17 11:07:51 PDT 2022
shafik updated this revision to Diff 453350.
shafik marked 2 inline comments as done.
shafik added a comment.
- Simplify condition to set `ConstexprVar` even more
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D131874/new/
https://reviews.llvm.org/D131874
Files:
clang/lib/AST/ExprConstant.cpp
clang/test/SemaCXX/constant-expression-cxx11.cpp
Index: clang/test/SemaCXX/constant-expression-cxx11.cpp
===================================================================
--- clang/test/SemaCXX/constant-expression-cxx11.cpp
+++ clang/test/SemaCXX/constant-expression-cxx11.cpp
@@ -2419,6 +2419,13 @@
enum EMaxInt {emaxint1=-1, emaxint2=__INT_MAX__};
+enum NumberType {};
+
+E2 testDefaultArgForParam(E2 e2Param = (E2)-1) { // ok, not a constant expression context
+ E2 e2LocalInit = e2Param; // ok, not a constant expression context
+ return e2LocalInit;
+}
+
void testValueInRangeOfEnumerationValues() {
constexpr E1 x1 = static_cast<E1>(-8);
constexpr E1 x2 = static_cast<E1>(8);
@@ -2454,6 +2461,8 @@
constexpr EMaxInt x19 = static_cast<EMaxInt>(__INT_MAX__-1);
constexpr EMaxInt x20 = static_cast<EMaxInt>((long)__INT_MAX__+1);
// expected-error at -1 {{integer value 2147483648 is outside the valid range of values [-2147483648, 2147483647] for this enumeration type}}
+
+ const NumberType neg_one = (NumberType) ((NumberType) 0 - (NumberType) 1); // ok, not a constant expression context
}
enum SortOrder {
@@ -2470,3 +2479,8 @@
return;
}
}
+
+GH50055::E2 GlobalInitNotCE1 = (GH50055::E2)-1; // ok, not a constant expression context
+GH50055::E2 GlobalInitNotCE2 = GH50055::testDefaultArgForParam(); // ok, not a constant expression context
+constexpr GH50055::E2 GlobalInitCE = (GH50055::E2)-1;
+// expected-error at -1 {{integer value -1 is outside the valid range of values [0, 7] for this enumeration type}}
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -13536,6 +13536,18 @@
if (Info.Ctx.getLangOpts().CPlusPlus && Info.InConstantContext &&
Info.EvalMode == EvalInfo::EM_ConstantExpression &&
DestType->isEnumeralType()) {
+
+ bool ConstexprVar = true;
+
+ // We know if we are here that we are in a context that we might require
+ // a constant expression or a context that requires a constant
+ // value. But if we are initializing a value we don't know if it is a
+ // constexpr variable or not. We can check the EvaluatingDecl to determine
+ // if it constexpr or not. If not then we don't want to emit a diagnostic.
+ if (const auto *VD = dyn_cast_or_null<VarDecl>(
+ Info.EvaluatingDecl.dyn_cast<const ValueDecl *>()))
+ ConstexprVar = VD->isConstexpr();
+
const EnumType *ET = dyn_cast<EnumType>(DestType.getCanonicalType());
const EnumDecl *ED = ET->getDecl();
// Check that the value is within the range of the enumeration values.
@@ -13555,13 +13567,14 @@
ED->getValueRange(Max, Min);
--Max;
- if (ED->getNumNegativeBits() &&
+ if (ED->getNumNegativeBits() && ConstexprVar &&
(Max.slt(Result.getInt().getSExtValue()) ||
Min.sgt(Result.getInt().getSExtValue())))
- Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
- diag::warn_constexpr_unscoped_enum_out_of_range)
- << llvm::toString(Result.getInt(),10) << Min.getSExtValue() << Max.getSExtValue();
- else if (!ED->getNumNegativeBits() &&
+ Info.Ctx.getDiagnostics().Report(
+ E->getExprLoc(), diag::warn_constexpr_unscoped_enum_out_of_range)
+ << llvm::toString(Result.getInt(), 10) << Min.getSExtValue()
+ << Max.getSExtValue();
+ else if (!ED->getNumNegativeBits() && ConstexprVar &&
Max.ult(Result.getInt().getZExtValue()))
Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
diag::warn_constexpr_unscoped_enum_out_of_range)
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