[clang] 28cd7f8 - Revert "[Clang] Diagnose ill-formed constant expression when setting a non fixed enum to a value outside the range of the enumeration values"

Shafik Yaghmour via cfe-commits cfe-commits at lists.llvm.org
Wed Jul 27 15:32:07 PDT 2022


Author: Shafik Yaghmour
Date: 2022-07-27T15:31:41-07:00
New Revision: 28cd7f86ed0e94ea3ae56a49ba85f0ccb7b51dd4

URL: https://github.com/llvm/llvm-project/commit/28cd7f86ed0e94ea3ae56a49ba85f0ccb7b51dd4
DIFF: https://github.com/llvm/llvm-project/commit/28cd7f86ed0e94ea3ae56a49ba85f0ccb7b51dd4.diff

LOG: Revert "[Clang] Diagnose ill-formed constant expression when setting a non fixed enum to a value outside the range of the enumeration values"

This reverts commit a3710589f285de0bb22ff92b1fc24df9411e986f.

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/include/clang/AST/Decl.h
    clang/include/clang/Basic/DiagnosticASTKinds.td
    clang/lib/AST/Decl.cpp
    clang/lib/AST/ExprConstant.cpp
    clang/lib/CodeGen/CGExpr.cpp
    clang/test/Sema/aarch64-sve-intrinsics/acle_sve_imm.cpp
    clang/test/SemaCXX/constant-expression-cxx11.cpp
    clang/test/SemaTemplate/temp_arg_enum_printing.cpp
    clang/www/cxx_dr_status.html

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index a65a41357523d..4f5e71e0ba808 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -52,10 +52,6 @@ Bug Fixes
 
 Improvements to Clang's diagnostics
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-- Clang will now correctly diagnose as ill-formed a constant expression where an
-  enum without a fixed underlying type is set to a value outside the range of
-  of the enumerations values. Fixes
-  `Issue 50055: <https://github.com/llvm/llvm-project/issues/50055>`_.
 
 Non-comprehensive list of changes in this release
 -------------------------------------------------

diff  --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
index 6441cd339d917..fb87a75a1241f 100644
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -3842,11 +3842,6 @@ class EnumDecl : public TagDecl {
   ///                     -101     1001011                     8
   unsigned getNumNegativeBits() const { return EnumDeclBits.NumNegativeBits; }
 
-  /// Calculates the [Min,Max) values the enum can store based on the
-  /// NumPositiveBits and NumNegativeBits. This matters for enums that do not
-  /// have a fixed underlying type.
-  void getValueRange(llvm::APInt &Max, llvm::APInt &Min) const;
-
   /// Returns true if this is a C++11 scoped enumeration.
   bool isScoped() const { return EnumDeclBits.IsScoped; }
 

diff  --git a/clang/include/clang/Basic/DiagnosticASTKinds.td b/clang/include/clang/Basic/DiagnosticASTKinds.td
index 93e4dfecc49c1..5e694c6ad07ba 100644
--- a/clang/include/clang/Basic/DiagnosticASTKinds.td
+++ b/clang/include/clang/Basic/DiagnosticASTKinds.td
@@ -366,9 +366,6 @@ def note_constexpr_unsupported_layout : Note<
   "type %0 has unexpected layout">;
 def note_constexpr_unsupported_flexible_array : Note<
   "flexible array initialization is not yet supported">;
-def note_constexpr_unscoped_enum_out_of_range : Note<
-  "integer value %0 is outside the valid range of values [%1, %2) for this "
-  "enumeration type">;
 def err_experimental_clang_interp_failed : Error<
   "the experimental clang interpreter failed to evaluate an expression">;
 

diff  --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 030792bfc7ca3..aaba4345587b2 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -4621,21 +4621,6 @@ SourceRange EnumDecl::getSourceRange() const {
   return Res;
 }
 
-void EnumDecl::getValueRange(llvm::APInt &Max, llvm::APInt &Min) const {
-  unsigned Bitwidth = getASTContext().getIntWidth(getIntegerType());
-  unsigned NumNegativeBits = getNumNegativeBits();
-  unsigned NumPositiveBits = getNumPositiveBits();
-
-  if (NumNegativeBits) {
-    unsigned NumBits = std::max(NumNegativeBits, NumPositiveBits + 1);
-    Max = llvm::APInt(Bitwidth, 1) << (NumBits - 1);
-    Min = -Max;
-  } else {
-    Max = llvm::APInt(Bitwidth, 1) << NumPositiveBits;
-    Min = llvm::APInt::getZero(Bitwidth);
-  }
-}
-
 //===----------------------------------------------------------------------===//
 // RecordDecl Implementation
 //===----------------------------------------------------------------------===//

diff  --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 0f15859fc07a4..9d92c848ccb84 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -13519,34 +13519,6 @@ bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
       return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
     }
 
-    if (const EnumType *ET = dyn_cast<EnumType>(DestType)) {
-      const EnumDecl *ED = ET->getDecl();
-      // Check that the value is within the range of the enumeration values.
-      //
-      // This corressponds to [expr.static.cast]p10 which says:
-      // A value of integral or enumeration type can be explicitly converted
-      // to a complete enumeration type ... If the enumeration type does not
-      // have a fixed underlying type, the value is unchanged if the original
-      // value is within the range of the enumeration values ([dcl.enum]), and
-      // otherwise, the behavior is undefined.
-      //
-      // This was resolved as part of DR2338 which has CD5 status.
-      if (!ED->isFixed()) {
-        llvm::APInt Min;
-        llvm::APInt Max;
-
-        ED->getValueRange(Max, Min);
-
-        if (ED->getNumNegativeBits() &&
-            (Max.sle(Result.getInt()) || Min.sgt(Result.getInt())))
-          CCEDiag(E, diag::note_constexpr_unscoped_enum_out_of_range)
-              << Result.getInt() << Min.getSExtValue() << Max.getSExtValue();
-        else if (!ED->getNumNegativeBits() && Max.ule(Result.getInt()))
-          CCEDiag(E, diag::note_constexpr_unscoped_enum_out_of_range)
-              << Result.getInt() << Min.getZExtValue() << Max.getZExtValue();
-      }
-    }
-
     return Success(HandleIntToIntCast(Info, E, DestType, SrcType,
                                       Result.getInt()), E);
   }

diff  --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 0b8c200335a04..bf3dd812b9e8d 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -1661,7 +1661,21 @@ static bool getRangeForType(CodeGenFunction &CGF, QualType Ty,
     End = llvm::APInt(CGF.getContext().getTypeSize(Ty), 2);
   } else {
     const EnumDecl *ED = ET->getDecl();
-    ED->getValueRange(End, Min);
+    llvm::Type *LTy = CGF.ConvertTypeForMem(ED->getIntegerType());
+    unsigned Bitwidth = LTy->getScalarSizeInBits();
+    unsigned NumNegativeBits = ED->getNumNegativeBits();
+    unsigned NumPositiveBits = ED->getNumPositiveBits();
+
+    if (NumNegativeBits) {
+      unsigned NumBits = std::max(NumNegativeBits, NumPositiveBits + 1);
+      assert(NumBits <= Bitwidth);
+      End = llvm::APInt(Bitwidth, 1) << (NumBits - 1);
+      Min = -End;
+    } else {
+      assert(NumPositiveBits <= Bitwidth);
+      End = llvm::APInt(Bitwidth, 1) << NumPositiveBits;
+      Min = llvm::APInt::getZero(Bitwidth);
+    }
   }
   return true;
 }

diff  --git a/clang/test/Sema/aarch64-sve-intrinsics/acle_sve_imm.cpp b/clang/test/Sema/aarch64-sve-intrinsics/acle_sve_imm.cpp
index cfd3b3685a0c7..7be8aec449c9f 100644
--- a/clang/test/Sema/aarch64-sve-intrinsics/acle_sve_imm.cpp
+++ b/clang/test/Sema/aarch64-sve-intrinsics/acle_sve_imm.cpp
@@ -206,19 +206,19 @@ void test_range_0_13(svbool_t pg, const void *const_void_ptr)
 {
   // expected-error-re at +1 {{argument value {{[0-9]+}} is outside the valid range [0, 13]}}
   svprfb(pg, const_void_ptr, svprfop(14));
-  // expected-error-re at +1 {{must be a constant integer}}
+  // expected-error-re at +1 {{argument value {{[0-9]+}} is outside the valid range [0, 13]}}
   svprfb_vnum(pg, const_void_ptr, 0, svprfop(-1));
   // expected-error-re at +1 {{argument value {{[0-9]+}} is outside the valid range [0, 13]}}
   svprfd(pg, const_void_ptr, svprfop(14));
-  // expected-error-re at +1 {{must be a constant integer}}
+  // expected-error-re at +1 {{argument value {{[0-9]+}} is outside the valid range [0, 13]}}
   svprfd_vnum(pg, const_void_ptr, 0, svprfop(-1));
   // expected-error-re at +1 {{argument value {{[0-9]+}} is outside the valid range [0, 13]}}
   svprfh(pg, const_void_ptr, svprfop(14));
-  // expected-error-re at +1 {{must be a constant integer}}
+  // expected-error-re at +1 {{argument value {{[0-9]+}} is outside the valid range [0, 13]}}
   svprfh_vnum(pg, const_void_ptr, 0, svprfop(-1));
   // expected-error-re at +1 {{argument value {{[0-9]+}} is outside the valid range [0, 13]}}
   svprfw(pg, const_void_ptr, svprfop(14));
-  // expected-error-re at +1 {{must be a constant integer}}
+  // expected-error-re at +1 {{argument value {{[0-9]+}} is outside the valid range [0, 13]}}
   svprfw_vnum(pg, const_void_ptr, 0, svprfop(-1));
 }
 

diff  --git a/clang/test/SemaCXX/constant-expression-cxx11.cpp b/clang/test/SemaCXX/constant-expression-cxx11.cpp
index d97c27426b94a..e0163fe1f2bb1 100644
--- a/clang/test/SemaCXX/constant-expression-cxx11.cpp
+++ b/clang/test/SemaCXX/constant-expression-cxx11.cpp
@@ -2399,50 +2399,3 @@ void local_constexpr_var() {
   constexpr int a = 0; // expected-note {{address of non-static constexpr variable 'a' may 
diff er on each invocation of the enclosing function; add 'static' to give it a constant address}}
   constexpr const int *p = &a; // expected-error {{constant expression}} expected-note {{pointer to 'a' is not a constant expression}}
 }
-
-namespace GH50055 {
-// Enums without fixed underlying type
-enum E1 {e11=-4, e12=4};
-enum E2 {e21=0, e22=4};
-enum E3 {e31=-4, e32=1024};
-enum E4 {e41=0};
-// Empty but as-if it had a single enumerator with value 0
-enum EEmpty {};
-
-// Enum with fixed underlying type because the underlying type is explicitly specified
-enum EFixed : int {efixed1=-4, efixed2=4};
-// Enum with fixed underlying type because it is scoped
-enum class EScoped {escoped1=-4, escoped2=4};
-
-void testValueInRangeOfEnumerationValues() {
-  constexpr E1 x1 = static_cast<E1>(-8);
-  constexpr E1 x2 = static_cast<E1>(8); // expected-error {{must be initialized by a constant expression}}
-  // expected-note at -1 {{integer value 8 is outside the valid range of values [-8, 8) for this enumeration type}}
-
-  constexpr E2 x3 = static_cast<E2>(-8); // expected-error {{must be initialized by a constant expression}}
-  // expected-note at -1 {{integer value -8 is outside the valid range of values [0, 8) for this enumeration type}}
-  constexpr E2 x4 = static_cast<E2>(0);
-  constexpr E2 x5 = static_cast<E2>(8); // expected-error {{must be initialized by a constant expression}}
-  // expected-note at -1 {{integer value 8 is outside the valid range of values [0, 8) for this enumeration type}}
-
-  constexpr E3 x6 = static_cast<E3>(-2048);
-  constexpr E3 x7 = static_cast<E3>(-8);
-  constexpr E3 x8 = static_cast<E3>(0);
-  constexpr E3 x9 = static_cast<E3>(8);
-  constexpr E3 x10 = static_cast<E3>(2048); // expected-error {{must be initialized by a constant expression}}
-  // expected-note at -1 {{integer value 2048 is outside the valid range of values [-2048, 2048) for this enumeration type}}
-
-  constexpr E4 x11 = static_cast<E4>(0);
-  constexpr E4 x12 = static_cast<E4>(1);
-  constexpr E4 x13 = static_cast<E4>(2); // expected-error {{must be initialized by a constant expression}}
-  // expected-note at -1 {{integer value 2 is outside the valid range of values [0, 2) for this enumeration type}}
-
-  constexpr EEmpty x14 = static_cast<EEmpty>(0);
-  constexpr EEmpty x15 = static_cast<EEmpty>(1);
-  constexpr EEmpty x16 = static_cast<EEmpty>(2); // expected-error {{must be initialized by a constant expression}}
-  // expected-note at -1 {{integer value 2 is outside the valid range of values [0, 2) for this enumeration type}}
-
-  constexpr EFixed x17 = static_cast<EFixed>(100);
-  constexpr EScoped x18 = static_cast<EScoped>(100);
-}
-}

diff  --git a/clang/test/SemaTemplate/temp_arg_enum_printing.cpp b/clang/test/SemaTemplate/temp_arg_enum_printing.cpp
index 5a486edd2d30d..c5570af82bc84 100644
--- a/clang/test/SemaTemplate/temp_arg_enum_printing.cpp
+++ b/clang/test/SemaTemplate/temp_arg_enum_printing.cpp
@@ -3,7 +3,7 @@
 namespace NamedEnumNS
 {
   
-enum class NamedEnum
+enum NamedEnum
 {
   Val0,
   Val1
@@ -13,9 +13,9 @@ template <NamedEnum E>
 void foo();
   
 void test() {
-  // CHECK: template<> void foo<NamedEnumNS::NamedEnum::Val0>()
-  NamedEnumNS::foo<NamedEnum::Val0>();
-  // CHECK: template<> void foo<NamedEnumNS::NamedEnum::Val1>()
+  // CHECK: template<> void foo<NamedEnumNS::Val0>()
+  NamedEnumNS::foo<Val0>();
+  // CHECK: template<> void foo<NamedEnumNS::Val1>()
   NamedEnumNS::foo<(NamedEnum)1>();
   // CHECK: template<> void foo<(NamedEnumNS::NamedEnum)2>()
   NamedEnumNS::foo<(NamedEnum)2>();

diff  --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index f3cfe9faea150..466f287c75d90 100755
--- a/clang/www/cxx_dr_status.html
+++ b/clang/www/cxx_dr_status.html
@@ -13842,7 +13842,7 @@ <h2 id="cxxdr">C++ defect report implementation status</h2>
     <td><a href="https://wg21.link/cwg2338">2338</a></td>
     <td>CD5</td>
     <td>Undefined behavior converting to short enums with fixed underlying types</td>
-    <td class="full" align="center">Clang 16</td>
+    <td class="full" align="center">Clang 12</td>
   </tr>
   <tr id="2339">
     <td><a href="https://wg21.link/cwg2339">2339</a></td>


        


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