Skip to content

[clang][bytecode] Fix getting pointer element type in __builtin_memcmp #130485

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Mar 9, 2025
Merged

[clang][bytecode] Fix getting pointer element type in __builtin_memcmp #130485

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 12 additions & 2 deletions clang/lib/AST/ByteCode/InterpBuiltin.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1881,11 +1881,21 @@ static bool interp__builtin_memcmp(InterpState &S, CodePtr OpPC,
bool IsWide =
(ID == Builtin::BIwmemcmp || ID == Builtin::BI__builtin_wmemcmp);

auto getElemType = [](const Pointer &P) -> QualType {
const Descriptor *Desc = P.getFieldDesc();
QualType T = Desc->getType();
if (T->isPointerType())
return T->getAs<PointerType>()->getPointeeType();
if (Desc->isArray())
return Desc->getElemQualType();
return T;
};

const ASTContext &ASTCtx = S.getASTContext();
// FIXME: This is an arbitrary limitation the current constant interpreter
// had. We could remove this.
if (!IsWide && (!isOneByteCharacterType(PtrA.getType()) ||
!isOneByteCharacterType(PtrB.getType()))) {
if (!IsWide && (!isOneByteCharacterType(getElemType(PtrA)) ||
!isOneByteCharacterType(getElemType(PtrB)))) {
S.FFDiag(S.Current->getSource(OpPC),
diag::note_constexpr_memcmp_unsupported)
<< ASTCtx.BuiltinInfo.getQuotedName(ID) << PtrA.getType()
Expand Down
15 changes: 15 additions & 0 deletions clang/test/AST/ByteCode/builtin-functions.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1352,6 +1352,21 @@ namespace Memcmp {
static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 7) == -1);
static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 6) == -1);
static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 5) == 0);

#if __cplusplus >= 202002L
constexpr bool f() {
char *c = new char[12];
c[0] = 'b';

char n = 'a';
bool b = __builtin_memcmp(c, &n, 1) == 0;

delete[] c;
return !b;
}
static_assert(f());
#endif

}

namespace Memchr {
Expand Down