r305903 - Function with unparsed body is a definition
Serge Pavlov via cfe-commits
cfe-commits at lists.llvm.org
Tue Aug 1 09:28:54 PDT 2017
Yes, sure, I will investigate it.
Thanks,
--Serge
2017-08-01 21:32 GMT+07:00 Alexander Kornienko <alexfh at google.com>:
> This change causes an assertion failure on valid code. Could you take a
> look at fixing this?
>
> A reduced test case:
>
> $ cat /tmp/SemaTemplateInstantiateDecl-crash2.cpp
> template <class T>
> constexpr void f(T) {
> f(0);
> }
> $ clang -fsyntax-only -std=c++11 /tmp/SemaTemplateInstantiateDecl-
> crash2.cpp
> assert.h assertion failed at llvm/tools/clang/lib/Sema/
> SemaTemplateInstantiateDecl.cpp:3840 in void clang::Sema::
> InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl
> *, bool, bool, bool): (Pattern |
> | PatternDecl->isDefaulted()) && "unexpected kind of function template
> definition"
> *** Check failure stack trace: ***
> @ 0x6094c4a __assert_fail
> @ 0x2705bfe clang::Sema::InstantiateFunctionDefinition()
> @ 0x2c1fb13 clang::Sema::MarkFunctionReferenced()
> @ 0x2bec07b clang::Sema::MarkAnyDeclReferenced()
> @ 0x2c2327f MarkExprReferenced()
> @ 0x2be8f0a clang::Sema::MarkDeclRefReferenced()
> @ 0x2980ac0 clang::Sema::FixOverloadedFunctionReference()
> @ 0x2982e66 FinishOverloadedCallExpr()
> @ 0x2982b39 clang::Sema::BuildOverloadedCallExpr()
> @ 0x2be461b clang::Sema::ActOnCallExpr()
> @ 0x2571e90 clang::Parser::ParsePostfixExpressionSuffix()
> @ 0x25784cb clang::Parser::ParseCastExpression()
> @ 0x2570865 clang::Parser::ParseCastExpression()
> @ 0x256f1e3 clang::Parser::ParseAssignmentExpression()
> @ 0x256f0bf clang::Parser::ParseExpression()
> @ 0x2517eeb clang::Parser::ParseExprStatement()
> @ 0x2517074 clang::Parser::ParseStatementOrDeclarationAft
> erAttributes()
> @ 0x2516b50 clang::Parser::ParseStatementOrDeclaration()
> @ 0x251deb4 clang::Parser::ParseCompoundStatementBody()
> @ 0x251ea53 clang::Parser::ParseFunctionStatementBody()
> @ 0x24f5b23 clang::Parser::ParseFunctionDefinition()
> @ 0x25082a5 clang::Parser::ParseSingleDeclarationAfterTem
> plate()
> @ 0x2507652 clang::Parser::ParseTemplateDeclarationOrSpec
> ialization()
> @ 0x2506fa5 clang::Parser::ParseDeclarationStartingWithTe
> mplate()
> @ 0x25b6853 clang::Parser::ParseDeclaration()
> @ 0x24f36d5 clang::Parser::ParseExternalDeclaration()
> @ 0x24f2739 clang::Parser::ParseTopLevelDecl()
> @ 0x24f220e clang::Parser::ParseFirstTopLevelDecl()
> @ 0x24ed582 clang::ParseAST()
>
> On Wed, Jun 21, 2017 at 2:46 PM, Serge Pavlov via cfe-commits <
> cfe-commits at lists.llvm.org> wrote:
>
>> Author: sepavloff
>> Date: Wed Jun 21 07:46:57 2017
>> New Revision: 305903
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=305903&view=rev
>> Log:
>> Function with unparsed body is a definition
>>
>> While a function body is being parsed, the function declaration is not
>> considered
>> as a definition because it does not have a body yet. In some cases it
>> leads to
>> incorrect interpretation, the case is presented in
>> https://bugs.llvm.org/show_bug.cgi?id=14785:
>> ```
>> template<typename T> struct Somewhat {
>> void internal() const {}
>> friend void operator+(int const &, Somewhat<T> const &) {}
>> };
>> void operator+(int const &, Somewhat<char> const &x) { x.internal(); }
>> ```
>> When statement `x.internal()` in the body of global `operator+` is
>> parsed, the type
>> of `x` must be completed, so the instantiation of `Somewhat<char>` is
>> started. It
>> instantiates the declaration of `operator+` defined inline, and makes a
>> check for
>> redefinition. The check does not detect another definition because the
>> declaration
>> of `operator+` is still not defining as does not have a body yet.
>>
>> To solves this problem the function `isThisDeclarationADefinition`
>> considers
>> a function declaration as a definition if it has flag `WillHaveBody` set.
>>
>> This change fixes PR14785.
>>
>> Differential Revision: https://reviews.llvm.org/D30375
>>
>> This is a recommit of 305379, reverted in 305381, with small changes.
>>
>> Modified:
>> cfe/trunk/include/clang/AST/Decl.h
>> cfe/trunk/lib/Sema/SemaCUDA.cpp
>> cfe/trunk/lib/Sema/SemaDecl.cpp
>> cfe/trunk/lib/Sema/SemaDeclCXX.cpp
>> cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
>> cfe/trunk/test/SemaCXX/friend2.cpp
>>
>> Modified: cfe/trunk/include/clang/AST/Decl.h
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/
>> AST/Decl.h?rev=305903&r1=305902&r2=305903&view=diff
>> ============================================================
>> ==================
>> --- cfe/trunk/include/clang/AST/Decl.h (original)
>> +++ cfe/trunk/include/clang/AST/Decl.h Wed Jun 21 07:46:57 2017
>> @@ -1874,7 +1874,7 @@ public:
>> ///
>> bool isThisDeclarationADefinition() const {
>> return IsDeleted || IsDefaulted || Body || IsLateTemplateParsed ||
>> - hasDefiningAttr();
>> + WillHaveBody || hasDefiningAttr();
>> }
>>
>> /// doesThisDeclarationHaveABody - Returns whether this specific
>>
>> Modified: cfe/trunk/lib/Sema/SemaCUDA.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaC
>> UDA.cpp?rev=305903&r1=305902&r2=305903&view=diff
>> ============================================================
>> ==================
>> --- cfe/trunk/lib/Sema/SemaCUDA.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaCUDA.cpp Wed Jun 21 07:46:57 2017
>> @@ -629,12 +629,6 @@ static bool IsKnownEmitted(Sema &S, Func
>> // emitted, because (say) the definition could include "inline".
>> FunctionDecl *Def = FD->getDefinition();
>>
>> - // We may currently be parsing the body of FD, in which case
>> - // FD->getDefinition() will be null, but we still want to treat FD as
>> though
>> - // it's a definition.
>> - if (!Def && FD->willHaveBody())
>> - Def = FD;
>> -
>> if (Def &&
>> !isDiscardableGVALinkage(S.getASTContext().GetGVALinkageFor
>> Function(Def)))
>> return true;
>>
>> Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaD
>> ecl.cpp?rev=305903&r1=305902&r2=305903&view=diff
>> ============================================================
>> ==================
>> --- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaDecl.cpp Wed Jun 21 07:46:57 2017
>> @@ -12232,6 +12232,7 @@ Decl *Sema::ActOnFinishFunctionBody(Decl
>>
>> if (FD) {
>> FD->setBody(Body);
>> + FD->setWillHaveBody(false);
>>
>> if (getLangOpts().CPlusPlus14) {
>> if (!FD->isInvalidDecl() && Body && !FD->isDependentContext() &&
>>
>> Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaD
>> eclCXX.cpp?rev=305903&r1=305902&r2=305903&view=diff
>> ============================================================
>> ==================
>> --- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Wed Jun 21 07:46:57 2017
>> @@ -13878,6 +13878,9 @@ void Sema::SetDeclDeleted(Decl *Dcl, Sou
>> return;
>> }
>>
>> + // Deleted function does not have a body.
>> + Fn->setWillHaveBody(false);
>> +
>> if (const FunctionDecl *Prev = Fn->getPreviousDecl()) {
>> // Don't consider the implicit declaration we generate for explicit
>> // specializations. FIXME: Do not generate these implicit
>> declarations.
>>
>> Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaT
>> emplateInstantiateDecl.cpp?rev=305903&r1=305902&r2=305903&view=diff
>> ============================================================
>> ==================
>> --- cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp Wed Jun 21
>> 07:46:57 2017
>> @@ -1782,6 +1782,9 @@ Decl *TemplateDeclInstantiator::VisitFun
>> Previous.clear();
>> }
>>
>> + if (isFriend)
>> + Function->setObjectOfFriendDecl();
>> +
>> SemaRef.CheckFunctionDeclaration(/*Scope*/ nullptr, Function,
>> Previous,
>> isExplicitSpecialization);
>>
>>
>> Modified: cfe/trunk/test/SemaCXX/friend2.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/
>> friend2.cpp?rev=305903&r1=305902&r2=305903&view=diff
>> ============================================================
>> ==================
>> --- cfe/trunk/test/SemaCXX/friend2.cpp (original)
>> +++ cfe/trunk/test/SemaCXX/friend2.cpp Wed Jun 21 07:46:57 2017
>> @@ -170,3 +170,40 @@ struct Test {
>> template class Test<int>;
>>
>> }
>> +
>> +namespace pr14785 {
>> +template<typename T>
>> +struct Somewhat {
>> + void internal() const { }
>> + friend void operator+(int const &, Somewhat<T> const &) {} //
>> expected-error{{redefinition of 'operator+'}}
>> +};
>> +
>> +void operator+(int const &, Somewhat<char> const &x) { // expected-note
>> {{previous definition is here}}
>> + x.internal(); // expected-note{{in instantiation of template class
>> 'pr14785::Somewhat<char>' requested here}}
>> +}
>> +}
>> +
>> +namespace D30375 {
>> +template <typename K> struct B {
>> + template <typename A> bool insert(A &);
>> +};
>> +
>> +template <typename K>
>> +template <typename A> bool B<K>::insert(A &x) { return x < x; }
>> +
>> +template <typename K> class D {
>> + B<K> t;
>> +
>> +public:
>> + K x;
>> + bool insert() { return t.insert(x); }
>> + template <typename K1> friend bool operator<(const D<K1> &, const
>> D<K1> &);
>> +};
>> +
>> +template <typename K> bool operator<(const D<K> &, const D<K> &);
>> +
>> +void func() {
>> + D<D<int>> cache;
>> + cache.insert();
>> +}
>> +}
>>
>>
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>>
>
>
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