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[clang][bytecode] Handle __builtin_wcslen #119187

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Merged
merged 1 commit into from
Dec 9, 2024
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[clang][bytecode] Handle __builtin_wcslen #119187

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25 changes: 23 additions & 2 deletions clang/lib/AST/ByteCode/InterpBuiltin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -243,7 +243,7 @@ static bool interp__builtin_strlen(InterpState &S, CodePtr OpPC,
unsigned ID = Func->getBuiltinID();
const Pointer &StrPtr = getParam<Pointer>(Frame, 0);

if (ID == Builtin::BIstrlen)
if (ID == Builtin::BIstrlen || ID == Builtin::BIwcslen)
diagnoseNonConstexprBuiltin(S, OpPC, ID);

if (!CheckArray(S, OpPC, StrPtr))
Expand All @@ -256,6 +256,12 @@ static bool interp__builtin_strlen(InterpState &S, CodePtr OpPC,
return false;

assert(StrPtr.getFieldDesc()->isPrimitiveArray());
unsigned ElemSize = StrPtr.getFieldDesc()->getElemSize();

if (ID == Builtin::BI__builtin_wcslen || ID == Builtin::BIwcslen) {
const ASTContext &AC = S.getASTContext();
assert(ElemSize == AC.getTypeSizeInChars(AC.getWCharType()).getQuantity());
}

size_t Len = 0;
for (size_t I = StrPtr.getIndex();; ++I, ++Len) {
Expand All @@ -264,7 +270,20 @@ static bool interp__builtin_strlen(InterpState &S, CodePtr OpPC,
if (!CheckRange(S, OpPC, ElemPtr, AK_Read))
return false;

uint8_t Val = ElemPtr.deref<uint8_t>();
uint32_t Val;
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Should we assert that if ID == Builtin::BIwcslen ElemSize is the size of wchar_t?

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Done

switch (ElemSize) {
case 1:
Val = ElemPtr.deref<uint8_t>();
break;
case 2:
Val = ElemPtr.deref<uint16_t>();
break;
case 4:
Val = ElemPtr.deref<uint32_t>();
break;
default:
llvm_unreachable("Unsupported char size");
}
if (Val == 0)
break;
}
Expand Down Expand Up @@ -1859,6 +1878,8 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
break;
case Builtin::BI__builtin_strlen:
case Builtin::BIstrlen:
case Builtin::BI__builtin_wcslen:
case Builtin::BIwcslen:
if (!interp__builtin_strlen(S, OpPC, Frame, F, Call))
return false;
break;
Expand Down
12 changes: 12 additions & 0 deletions clang/test/AST/ByteCode/builtin-functions.cpp
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Expand Up @@ -15,6 +15,10 @@
#error "huh?"
#endif

extern "C" {
typedef decltype(sizeof(int)) size_t;
extern size_t wcslen(const wchar_t *p);
}

namespace strcmp {
constexpr char kFoobar[6] = {'f','o','o','b','a','r'};
Expand Down Expand Up @@ -93,6 +97,14 @@ constexpr const char *a = "foo\0quux";
constexpr char d[] = { 'f', 'o', 'o' }; // no nul terminator.
constexpr int bad = __builtin_strlen(d); // both-error {{constant expression}} \
// both-note {{one-past-the-end}}

constexpr int wn = __builtin_wcslen(L"hello");
static_assert(wn == 5);
constexpr int wm = wcslen(L"hello"); // both-error {{constant expression}} \
// both-note {{non-constexpr function 'wcslen' cannot be used in a constant expression}}

int arr[3]; // both-note {{here}}
int wk = arr[wcslen(L"hello")]; // both-warning {{array index 5}}
}

namespace nan {
Expand Down
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