[clang] 8e4a867 - Revert "PR45083: Mark statement expressions as being dependent if they contain"
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Fri Mar 6 15:46:49 PST 2020
On Fri, 6 Mar 2020 at 02:11, Stephan Herhut via cfe-commits <
cfe-commits at lists.llvm.org> wrote:
> Author: Stephan Herhut
> Date: 2020-03-06T11:09:45+01:00
> New Revision: 8e4a8677be3061317056335d298d85ce60c23dff
>
> URL:
> https://github.com/llvm/llvm-project/commit/8e4a8677be3061317056335d298d85ce60c23dff
> DIFF:
> https://github.com/llvm/llvm-project/commit/8e4a8677be3061317056335d298d85ce60c23dff.diff
>
> LOG: Revert "PR45083: Mark statement expressions as being dependent if
> they contain"
>
> This reverts commit a95cc77be154433c37a3110ac9af394b7447fcba.
>
> Causes an internal build failure. I followed up with the author by mail.
>
The internal build failure is on invalid code that Clang incorrectly
accepted previously. Unreverting...
> Added:
>
>
> Modified:
> clang/include/clang/AST/Expr.h
> clang/lib/AST/Expr.cpp
> clang/test/SemaTemplate/dependent-expr.cpp
>
> Removed:
>
>
>
>
> ################################################################################
> diff --git a/clang/include/clang/AST/Expr.h
> b/clang/include/clang/AST/Expr.h
> index 75b7a5f6ecd3..7271dbb830a2 100644
> --- a/clang/include/clang/AST/Expr.h
> +++ b/clang/include/clang/AST/Expr.h
> @@ -3959,8 +3959,14 @@ class StmtExpr : public Expr {
> Stmt *SubStmt;
> SourceLocation LParenLoc, RParenLoc;
> public:
> - StmtExpr(CompoundStmt *SubStmt, QualType T,
> - SourceLocation LParen, SourceLocation RParen);
> + // FIXME: Does type-dependence need to be computed
> diff erently?
> + // FIXME: Do we need to compute instantiation instantiation-dependence
> for
> + // statements? (ugh!)
> + StmtExpr(CompoundStmt *substmt, QualType T,
> + SourceLocation lp, SourceLocation rp) :
> + Expr(StmtExprClass, T, VK_RValue, OK_Ordinary,
> + T->isDependentType(), false, false, false),
> + SubStmt(substmt), LParenLoc(lp), RParenLoc(rp) { }
>
> /// Build an empty statement expression.
> explicit StmtExpr(EmptyShell Empty) : Expr(StmtExprClass, Empty) { }
>
> diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
> index 78fd96fd76e6..79f9f42224d0 100644
> --- a/clang/lib/AST/Expr.cpp
> +++ b/clang/lib/AST/Expr.cpp
> @@ -4097,53 +4097,6 @@ void ExtVectorElementExpr::getEncodedElementAccess(
> }
> }
>
> -StmtExpr::StmtExpr(CompoundStmt *SubStmt, QualType T, SourceLocation
> LParen,
> - SourceLocation RParen)
> - : Expr(StmtExprClass, T, VK_RValue, OK_Ordinary, T->isDependentType(),
> - false, false, false),
> - SubStmt(SubStmt), LParenLoc(LParen), RParenLoc(RParen) {
> - llvm::SmallVector<Stmt*, 16> Queue(1, SubStmt);
> - while (!Queue.empty()) {
> - Stmt *S = Queue.pop_back_val();
> - if (!S)
> - continue;
> -
> - // If any subexpression is dependent, the statement expression is
> dependent
> - // in the same way.
> - if (Expr *E = dyn_cast<Expr>(S)) {
> - addDependence(E->getDependence());
> - continue;
> - }
> -
> - // FIXME: Need to properly compute whether DeclStmts contain
> unexpanded
> - // parameter packs.
> - if (DeclStmt *DS = dyn_cast<DeclStmt>(S)) {
> - for (Decl *D : DS->decls()) {
> - // If any contained declaration is in a dependent context, then it
> - // needs to be instantiated, so the statement expression itself is
> - // instantiation-dependent.
> - //
> - // Note that we don't need to worry about the case where the
> context is
> - // non-dependent but contains dependent entities here (eg, inside
> a
> - // variable template or alias template): that can only happen at
> file
> - // scope, where statement expressions are prohibited.
> - if (D->getLexicalDeclContext()->isDependentContext())
> - addDependence(ExprDependence::Instantiation);
> -
> - // If any contained variable declaration has a dependent type, we
> can't
> - // evaluate that declaration.
> - if (auto *VD = dyn_cast<VarDecl>(D))
> - if (VD->getType()->isDependentType())
> - addDependence(ExprDependence::Value);
> - }
> - }
> -
> - // Recurse to substatements.
> - // FIXME: Should we skip the unchosen side of 'if constexpr' if known?
> - Queue.insert(Queue.end(), S->child_begin(), S->child_end());
> - }
> -}
> -
> ShuffleVectorExpr::ShuffleVectorExpr(const ASTContext &C, ArrayRef<Expr*>
> args,
> QualType Type, SourceLocation BLoc,
> SourceLocation RP)
>
> diff --git a/clang/test/SemaTemplate/dependent-expr.cpp
> b/clang/test/SemaTemplate/dependent-expr.cpp
> index 12a99acc21cd..bb1e239c3490 100644
> --- a/clang/test/SemaTemplate/dependent-expr.cpp
> +++ b/clang/test/SemaTemplate/dependent-expr.cpp
> @@ -1,4 +1,5 @@
> -// RUN: %clang_cc1 -fsyntax-only -verify -std=c++2a %s
> +// RUN: %clang_cc1 -fsyntax-only -verify %s
> +// expected-no-diagnostics
>
> // PR5908
> template <typename Iterator>
> @@ -107,42 +108,3 @@ namespace PR18152 {
> };
> template struct A<0>;
> }
> -
> -template<typename T> void stmt_expr_1() {
> - // GCC doesn't check this: it appears to treat statement-expressions as
> being
> - // value-dependent if they appear in a dependent context, regardless of
> their
> - // contents.
> - static_assert( ({ false; }), "" ); // expected-error {{failed}}
> -}
> -void stmt_expr_2() {
> - static_assert( ({ false; }), "" ); // expected-error {{failed}}
> -}
> -
> -namespace PR45083 {
> - struct A { bool x; };
> -
> - template<typename> struct B : A {
> - void f() {
> - const int n = ({ if (x) {} 0; });
> - }
> - };
> -
> - template void B<int>::f();
> -
> - template<typename> void f() {
> - decltype(({})) x; // expected-error {{incomplete type}}
> - }
> - template void f<int>();
> -
> - template<typename> auto g() {
> - auto c = [](auto, int) -> decltype(({})) {};
> - using T = decltype(c(0.0, 0));
> - using T = void;
> - return c(0, 0);
> - }
> - using U = decltype(g<int>()); // expected-note {{previous}}
> - using U = float; // expected-error {{
> diff erent types ('float' vs 'decltype(g<int>())' (aka 'void'))}}
> -
> - void h(auto a, decltype(g<char>())*) {} // expected-note {{previous}}
> - void h(auto a, void*) {} // expected-error {{redefinition}}
> -}
>
>
>
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