[clang] a1a71b7 - [Clang] Fix capture of values initialized by bitfields

[Corentin Jabot via cfe-commits]

Author: Corentin Jabot
Date: 2022-08-04T23:58:47+02:00
New Revision: a1a71b7dc97b35133425a31ede90c40529f1be9e

URL: https://github.com/llvm/llvm-project/commit/a1a71b7dc97b35133425a31ede90c40529f1be9e
DIFF: https://github.com/llvm/llvm-project/commit/a1a71b7dc97b35133425a31ede90c40529f1be9e.diff

LOG: [Clang] Fix capture of values initialized by bitfields

This fixes a regression introduced in 127bf44

Differential Revision: https://reviews.llvm.org/D131202

Added: 
    

Modified: 
    clang/include/clang/Basic/DiagnosticSemaKinds.td
    clang/lib/Sema/SemaExpr.cpp
    clang/test/SemaCXX/cxx1z-decomposition.cpp

Removed: 
    


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diff  --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 550ad5ab73c64..13209d3bff24f 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -9013,8 +9013,6 @@ def ext_ms_anonymous_record : ExtWarn<
 def err_reference_to_local_in_enclosing_context : Error<
   "reference to local %select{variable|binding}1 %0 declared in enclosing "
   "%select{%3|block literal|lambda expression|context}2">;
-def err_bitfield_capture_by_ref : Error<
-  "cannot capture a bit-field by reference">;
 def err_capture_binding_openmp : Error<
   "capturing a structured binding is not yet supported in OpenMP">;
 def ext_capture_binding : ExtWarn<

diff  --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 9497c4b5d5300..152f15159fa1f 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -18533,32 +18533,8 @@ static bool captureInLambda(LambdaScopeInfo *LSI, ValueDecl *Var,
   } else {
     ByRef = (LSI->ImpCaptureStyle == LambdaScopeInfo::ImpCap_LambdaByref);
   }
-  // C++20 : [expr.prim.lambda.capture]p12
-  // A bit-field or a member of an anonymous union shall
-  // not be captured by reference.
-  MemberExpr *ME = nullptr;
-  BindingDecl *BD = nullptr;
-  if (auto *V = dyn_cast<VarDecl>(Var)) {
-    if (V->getInit())
-      ME = dyn_cast<MemberExpr>(V->getInit()->IgnoreImplicit());
-  } else if ((BD = dyn_cast<BindingDecl>(Var))) {
-    ME = dyn_cast_or_null<MemberExpr>(BD->getBinding());
-  }
-
-  // Capturing a bitfield by reference is not allowed except in OpenMP.
-  if (ByRef && ME &&
-      (isa<BindingDecl>(Var) || !S.LangOpts.OpenMP ||
-       !S.isOpenMPCapturedDecl(Var))) {
-    const auto *FD = dyn_cast_or_null<FieldDecl>(ME->getMemberDecl());
-    if (FD && FD->isBitField()) {
-      if (BuildAndDiagnose) {
-        S.Diag(Loc, diag::err_bitfield_capture_by_ref) << Var;
-        S.Diag(Var->getLocation(), diag::note_entity_declared_at) << Var;
-        S.Diag(FD->getLocation(), diag::note_bitfield_decl) << FD;
-      }
-      Invalid = true;
-    }
-  }
+
+  BindingDecl *BD = dyn_cast<BindingDecl>(Var);
   // FIXME: We should support capturing structured bindings in OpenMP.
   if (!Invalid && BD && S.LangOpts.OpenMP) {
     if (BuildAndDiagnose) {

diff  --git a/clang/test/SemaCXX/cxx1z-decomposition.cpp b/clang/test/SemaCXX/cxx1z-decomposition.cpp
index 7165f30dc0703..13fe826759a34 100644
--- a/clang/test/SemaCXX/cxx1z-decomposition.cpp
+++ b/clang/test/SemaCXX/cxx1z-decomposition.cpp
@@ -84,9 +84,9 @@ void enclosing() {
 
   (void)[outerbit1]{}; // expected-error {{'outerbit1' cannot be captured because it does not have automatic storage duration}}
 
-  auto [bit, var] = S2{1, 1}; // expected-note 4{{'bit' declared here}}
+  auto [bit, var] = S2{1, 1}; // expected-note 2{{'bit' declared here}}
 
-  (void)[&bit] { // expected-error {{cannot capture a bit-field by reference}} \
+  (void)[&bit] { // expected-error {{non-const reference cannot bind to bit-field 'a'}} \
                     // expected-warning {{C++20}}
     return bit;
   };
@@ -96,7 +96,7 @@ void enclosing() {
   };
 
   (void)[&] { return bit + u; } // expected-error {{unnamed variable cannot be implicitly captured in a lambda expression}} \
-                                // expected-error {{cannot capture a bit-field by reference}} \
+                                // expected-error {{non-const reference cannot bind to bit-field 'a'}} \
                                 // expected-warning {{C++20}}
   ();
 }