================
@@ -2103,6 +2103,91 @@ static bool isOneByteCharacterType(QualType T) {
return T->isCharType() || T->isChar8Type();
}
+static bool interp__builtin_load8(InterpState &S, CodePtr OpPC,
+ const InterpFrame *Frame,
+ const CallExpr *Call, bool IsBigEndian,
+ bool IsAligned) {
+ Pointer Ptr = S.Stk.pop<Pointer>();
+
+ if (Ptr.isZero()) {
+ S.FFDiag(S.Current->getSource(OpPC), diag::note_constexpr_access_null)
+ << AK_Read;
+ return false;
+ }
+
+ if (!isReadable(Ptr) && !Ptr.isOnePastEnd())
+ return false;
+
+ if (IsAligned) {
+ CharUnits RequiredAlign =
+ S.getASTContext().getTypeAlignInChars(Call->getType());
+ APValue AV = Ptr.toAPValue(S.getASTContext());
+ CharUnits BaseAlignment =
+ GetBaseAlignment(S.getASTContext(), AV.getLValueBase());
+ CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(AV.getLValueOffset());
+ if (PtrAlign < RequiredAlign) {
+ S.FFDiag(S.Current->getSource(OpPC),
diag::note_constexpr_load8_unaligned)
+ << S.getASTContext().BuiltinInfo.getQuotedName(
+ Call->getBuiltinCallee())
+ << RequiredAlign.getQuantity() << PtrAlign.getQuantity();
+ return false;
+ }
+ }
+
+ // A string pointer has no Descriptor; treat it as an array of its
+ // character type.
+ bool IsArray;
+ QualType ElemTy;
+ if (Ptr.isStringPointer()) {
+ IsArray = true;
+ ElemTy = getElemType(Ptr);
+ } else {
+ const Descriptor *Desc = Ptr.getFieldDesc();
+ IsArray = Desc->isArray();
+ ElemTy = IsArray ? Desc->getElemQualType() : Desc->getType();
+ }
+
+ if (IsArray)
+ Ptr = Ptr.expand();
----------------
chaitanyav wrote:
Added tests in `clang/test/Sema/constexpr-builtin-stdc-load8.c`:
- Array of structs: `struct_arr_fail` and `struct_arr_n8_fail` (L122-L125)
- Union: `union_n8_fail` (L223)
Both interpreters reject them.
```
np4.c:5:33: error: constexpr variable 'struct_arr_fail' must be initialized by
a constant expression
np4.c:5:68: note: this conversion is not allowed in a constant expression
5 | constexpr __UINT_LEAST32_TYPE__ struct_arr_fail =
stdc_load8_leu32((const unsigned char *)non_char_arr);
| ^
np4.c:6:32: error: constexpr variable 'struct_arr_n8_fail' must be initialized
by a constant expression
np4.c:6:69: note: this conversion is not allowed in a constant expression
6 | constexpr __UINT_LEAST8_TYPE__ struct_arr_n8_fail =
stdc_load8_leu8((const unsigned char *)non_char_arr);
| ^
np4.c:9:32: error: constexpr variable 'union_n8_fail' must be initialized by a
constant expression
np4.c:9:64: note: this conversion is not allowed in a constant expression
9 | constexpr __UINT_LEAST8_TYPE__ union_n8_fail = stdc_load8_leu8((const
unsigned char *)&field_u);
| ^
```
```
np4.c:5:33: error: constexpr variable 'struct_arr_fail' must be initialized by
a constant expression
5 | constexpr __UINT_LEAST32_TYPE__ struct_arr_fail =
stdc_load8_leu32((const unsigned char *)non_char_arr);
| ^
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
np4.c:5:68: note: this conversion is not allowed in a constant expression
5 | constexpr __UINT_LEAST32_TYPE__ struct_arr_fail =
stdc_load8_leu32((const unsigned char *)non_char_arr);
|
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
np4.c:6:32: error: constexpr variable 'struct_arr_n8_fail' must be initialized
by a constant expression
6 | constexpr __UINT_LEAST8_TYPE__ struct_arr_n8_fail =
stdc_load8_leu8((const unsigned char *)non_char_arr);
| ^
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
np4.c:6:69: note: this conversion is not allowed in a constant expression
6 | constexpr __UINT_LEAST8_TYPE__ struct_arr_n8_fail =
stdc_load8_leu8((const unsigned char *)non_char_arr);
|
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
np4.c:9:32: error: constexpr variable 'union_n8_fail' must be initialized by a
constant expression
9 | constexpr __UINT_LEAST8_TYPE__ union_n8_fail = stdc_load8_leu8((const
unsigned char *)&field_u);
| ^
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
np4.c:9:64: note: this conversion is not allowed in a constant expression
9 | constexpr __UINT_LEAST8_TYPE__ union_n8_fail = stdc_load8_leu8((const
unsigned char *)&field_u);
|
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3 errors generated.
```
https://github.com/llvm/llvm-project/pull/203666
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