[PATCH] D76221: [Sema][SVE] Flip default RequireCompleteType behavior for sizeless types

[Richard Sandiford via Phabricator via cfe-commits]

rsandifo-arm created this revision.
rsandifo-arm added reviewers: sdesmalen, efriedma, rovka, rjmccall.
Herald added subscribers: cfe-commits, danielkiss, psnobl, jfb, rkruppe, kristof.beyls, tschuett.
Herald added a reviewer: rengolin.
Herald added a project: clang.
rsandifo-arm added a parent revision: D76219: [Sema][SVE] Reject "delete" with sizeless types.

Sizeless types are defined to be a form of incomplete type, but with
more relaxed rules in certain cases.  Previous patches in the series
took the following approach:

- Add tests for things that are explicitly supposed to be valid for sizeless types and that clang already handled correctly.

- Add diagnostics for things that are explicitly supposed to be invalid for sizeless types, in many cases inheriting the same rules as for incomplete types.

For any other cases, we should conservatively treat sizeless types as
in the same way as incomplete types.  This patch therefore flips the
default behavior for RequireCompleteType and co.  Callers that want
to accept sizeless types must then explicitly pass AcceptSizeless.

The Sema::BuildObjCEncodeExpression change is needed to keep
clang/test/CodeGenObjC/aarch64-sve-types.m passing.  If @encoding a
sizeless type will never be useful, we could enforce that here instead.

For reference, here's a list of every other function that now passes
AcceptSizeless, along with one example line from Sema/sizeless-1.c
or SemaCXX/sizeless-1.cpp that would regress without the change.

- CastOperation::CheckCStyleCast

  local_int8 = (svint8_t)0; // expected-error {{...arithmetic or pointer type is required...}}

- Sema::CheckParmsForFunctionDef

  int vararg_receiver(int count, svint8_t first, ...) {

- Sema::AddInitializerToDecl

  svint8_t init_int8 = local_int8;

- Sema::ActOnInitializerError

  svint8_t bad_init_int8 = for; // expected-error {{expected expression}}

- Sema::ActOnUninitializedDecl

  svint8_t local_int8;

- Sema::ActOnStartOfFunctionDef

  svint8_t ret_bad_conv() { return explicit_conv(); }

- Sema::SetParamDefaultArgument

  void with_default(svint8_t = svint8_t());

- Sema::BuildExceptionDeclaration

  } catch (svint8_t) { // expected-error {{...sizeless type...}}

- Sema::CheckSpecifiedExceptionType

  void throwing_func() throw(svint8_t); // expected-error {{...sizeless...}}

- Sema::DefaultVariadicArgumentPromotion

  varargs(1, local_int8, local_int16);

- Sema::GatherArgumentsForCall

  pass_int8(local_int8);

- Sema::BuildResolvedCallExpr

  noproto(local_int8);

- CheckCommaOperands

  0, local_int8;

- Sema::BuildVAArgExpr

  __builtin_va_arg(va, svint8_t);

- Sema::CheckCXXThrowOperand

  throw local_int8; // expected-error {{...sizeless type...}}

- Sema::BuildCXXTypeConstructExpr

  void with_default(svint8_t = svint8_t());

- CheckUnaryTypeTraitTypeCompleteness

  _Static_assert(__is_trivially_destructible(svint8_t), "");

- evaluateTypeTrait

  _Static_assert(__is_constructible(svint8_t), "");

- EvaluateBinaryTypeTrait

  _Static_assert(__is_convertible_to(svint8_t, svint8_t), ""); _Static_assert(!__is_assignable(svint8_t, svint8_t), "");

- Sema::IgnoredValueConversions

  (void)local_int8;

- CopyObject

  widget w(1);

- InitializationSequence::Diagnose

  svint8_t ret_bad_conv() { return explicit_conv(); }

- Sema::buildLambdaScope

  local_int8 = ([]() { return svint8_t(); })();

- TryListConversion

  template_fn_direct<svint8_t>({wrapper<svint8_t>()});

- Sema::AddConversionCandidate

  local_int8 = wrapper<svint8_t>();

- Sema::BuildCXXForRangeStmt

  for (auto x : local_int8) {

- Sema::BuildAtomicType

  _Atomic svint8_t atomic_int8; // expected-error {{...sizeless...}}


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D76221

Files:
  clang/include/clang/Sema/Sema.h
  clang/lib/Sema/SemaCast.cpp
  clang/lib/Sema/SemaChecking.cpp
  clang/lib/Sema/SemaDecl.cpp
  clang/lib/Sema/SemaDeclCXX.cpp
  clang/lib/Sema/SemaExceptionSpec.cpp
  clang/lib/Sema/SemaExpr.cpp
  clang/lib/Sema/SemaExprCXX.cpp
  clang/lib/Sema/SemaExprObjC.cpp
  clang/lib/Sema/SemaInit.cpp
  clang/lib/Sema/SemaLambda.cpp
  clang/lib/Sema/SemaOverload.cpp
  clang/lib/Sema/SemaStmt.cpp
  clang/lib/Sema/SemaType.cpp

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