| //===--- SemaCUDA.cpp - Semantic Analysis for CUDA constructs -------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| /// \file |
| /// \brief This file implements semantic analysis for CUDA constructs. |
| /// |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/AST/ASTContext.h" |
| #include "clang/AST/Decl.h" |
| #include "clang/AST/ExprCXX.h" |
| #include "clang/Lex/Preprocessor.h" |
| #include "clang/Sema/Lookup.h" |
| #include "clang/Sema/Sema.h" |
| #include "clang/Sema/SemaDiagnostic.h" |
| #include "clang/Sema/Template.h" |
| #include "llvm/ADT/Optional.h" |
| #include "llvm/ADT/SmallVector.h" |
| using namespace clang; |
| |
| ExprResult Sema::ActOnCUDAExecConfigExpr(Scope *S, SourceLocation LLLLoc, |
| MultiExprArg ExecConfig, |
| SourceLocation GGGLoc) { |
| FunctionDecl *ConfigDecl = Context.getcudaConfigureCallDecl(); |
| if (!ConfigDecl) |
| return ExprError(Diag(LLLLoc, diag::err_undeclared_var_use) |
| << "cudaConfigureCall"); |
| QualType ConfigQTy = ConfigDecl->getType(); |
| |
| DeclRefExpr *ConfigDR = new (Context) |
| DeclRefExpr(ConfigDecl, false, ConfigQTy, VK_LValue, LLLLoc); |
| MarkFunctionReferenced(LLLLoc, ConfigDecl); |
| |
| return ActOnCallExpr(S, ConfigDR, LLLLoc, ExecConfig, GGGLoc, nullptr, |
| /*IsExecConfig=*/true); |
| } |
| |
| /// IdentifyCUDATarget - Determine the CUDA compilation target for this function |
| Sema::CUDAFunctionTarget Sema::IdentifyCUDATarget(const FunctionDecl *D) { |
| if (D->hasAttr<CUDAInvalidTargetAttr>()) |
| return CFT_InvalidTarget; |
| |
| if (D->hasAttr<CUDAGlobalAttr>()) |
| return CFT_Global; |
| |
| if (D->hasAttr<CUDADeviceAttr>()) { |
| if (D->hasAttr<CUDAHostAttr>()) |
| return CFT_HostDevice; |
| return CFT_Device; |
| } else if (D->hasAttr<CUDAHostAttr>()) { |
| return CFT_Host; |
| } else if (D->isImplicit()) { |
| // Some implicit declarations (like intrinsic functions) are not marked. |
| // Set the most lenient target on them for maximal flexibility. |
| return CFT_HostDevice; |
| } |
| |
| return CFT_Host; |
| } |
| |
| // * CUDA Call preference table |
| // |
| // F - from, |
| // T - to |
| // Ph - preference in host mode |
| // Pd - preference in device mode |
| // H - handled in (x) |
| // Preferences: N:native, SS:same side, HD:host-device, WS:wrong side, --:never. |
| // |
| // | F | T | Ph | Pd | H | |
| // |----+----+-----+-----+-----+ |
| // | d | d | N | N | (c) | |
| // | d | g | -- | -- | (a) | |
| // | d | h | -- | -- | (e) | |
| // | d | hd | HD | HD | (b) | |
| // | g | d | N | N | (c) | |
| // | g | g | -- | -- | (a) | |
| // | g | h | -- | -- | (e) | |
| // | g | hd | HD | HD | (b) | |
| // | h | d | -- | -- | (e) | |
| // | h | g | N | N | (c) | |
| // | h | h | N | N | (c) | |
| // | h | hd | HD | HD | (b) | |
| // | hd | d | WS | SS | (d) | |
| // | hd | g | SS | -- |(d/a)| |
| // | hd | h | SS | WS | (d) | |
| // | hd | hd | HD | HD | (b) | |
| |
| Sema::CUDAFunctionPreference |
| Sema::IdentifyCUDAPreference(const FunctionDecl *Caller, |
| const FunctionDecl *Callee) { |
| assert(Callee && "Callee must be valid."); |
| CUDAFunctionTarget CalleeTarget = IdentifyCUDATarget(Callee); |
| CUDAFunctionTarget CallerTarget = |
| (Caller != nullptr) ? IdentifyCUDATarget(Caller) : Sema::CFT_Host; |
| |
| // If one of the targets is invalid, the check always fails, no matter what |
| // the other target is. |
| if (CallerTarget == CFT_InvalidTarget || CalleeTarget == CFT_InvalidTarget) |
| return CFP_Never; |
| |
| // (a) Can't call global from some contexts until we support CUDA's |
| // dynamic parallelism. |
| if (CalleeTarget == CFT_Global && |
| (CallerTarget == CFT_Global || CallerTarget == CFT_Device || |
| (CallerTarget == CFT_HostDevice && getLangOpts().CUDAIsDevice))) |
| return CFP_Never; |
| |
| // (b) Calling HostDevice is OK for everyone. |
| if (CalleeTarget == CFT_HostDevice) |
| return CFP_HostDevice; |
| |
| // (c) Best case scenarios |
| if (CalleeTarget == CallerTarget || |
| (CallerTarget == CFT_Host && CalleeTarget == CFT_Global) || |
| (CallerTarget == CFT_Global && CalleeTarget == CFT_Device)) |
| return CFP_Native; |
| |
| // (d) HostDevice behavior depends on compilation mode. |
| if (CallerTarget == CFT_HostDevice) { |
| // It's OK to call a compilation-mode matching function from an HD one. |
| if ((getLangOpts().CUDAIsDevice && CalleeTarget == CFT_Device) || |
| (!getLangOpts().CUDAIsDevice && |
| (CalleeTarget == CFT_Host || CalleeTarget == CFT_Global))) |
| return CFP_SameSide; |
| |
| // Calls from HD to non-mode-matching functions (i.e., to host functions |
| // when compiling in device mode or to device functions when compiling in |
| // host mode) are allowed at the sema level, but eventually rejected if |
| // they're ever codegened. TODO: Reject said calls earlier. |
| return CFP_WrongSide; |
| } |
| |
| // (e) Calling across device/host boundary is not something you should do. |
| if ((CallerTarget == CFT_Host && CalleeTarget == CFT_Device) || |
| (CallerTarget == CFT_Device && CalleeTarget == CFT_Host) || |
| (CallerTarget == CFT_Global && CalleeTarget == CFT_Host)) |
| return CFP_Never; |
| |
| llvm_unreachable("All cases should've been handled by now."); |
| } |
| |
| template <typename T> |
| static void EraseUnwantedCUDAMatchesImpl( |
| Sema &S, const FunctionDecl *Caller, llvm::SmallVectorImpl<T> &Matches, |
| std::function<const FunctionDecl *(const T &)> FetchDecl) { |
| if (Matches.size() <= 1) |
| return; |
| |
| // Gets the CUDA function preference for a call from Caller to Match. |
| auto GetCFP = [&](const T &Match) { |
| return S.IdentifyCUDAPreference(Caller, FetchDecl(Match)); |
| }; |
| |
| // Find the best call preference among the functions in Matches. |
| Sema::CUDAFunctionPreference BestCFP = GetCFP(*std::max_element( |
| Matches.begin(), Matches.end(), |
| [&](const T &M1, const T &M2) { return GetCFP(M1) < GetCFP(M2); })); |
| |
| // Erase all functions with lower priority. |
| Matches.erase( |
| llvm::remove_if(Matches, |
| [&](const T &Match) { return GetCFP(Match) < BestCFP; }), |
| Matches.end()); |
| } |
| |
| void Sema::EraseUnwantedCUDAMatches(const FunctionDecl *Caller, |
| SmallVectorImpl<FunctionDecl *> &Matches){ |
| EraseUnwantedCUDAMatchesImpl<FunctionDecl *>( |
| *this, Caller, Matches, [](const FunctionDecl *item) { return item; }); |
| } |
| |
| void Sema::EraseUnwantedCUDAMatches(const FunctionDecl *Caller, |
| SmallVectorImpl<DeclAccessPair> &Matches) { |
| EraseUnwantedCUDAMatchesImpl<DeclAccessPair>( |
| *this, Caller, Matches, [](const DeclAccessPair &item) { |
| return dyn_cast<FunctionDecl>(item.getDecl()); |
| }); |
| } |
| |
| void Sema::EraseUnwantedCUDAMatches( |
| const FunctionDecl *Caller, |
| SmallVectorImpl<std::pair<DeclAccessPair, FunctionDecl *>> &Matches){ |
| EraseUnwantedCUDAMatchesImpl<std::pair<DeclAccessPair, FunctionDecl *>>( |
| *this, Caller, Matches, |
| [](const std::pair<DeclAccessPair, FunctionDecl *> &item) { |
| return dyn_cast<FunctionDecl>(item.second); |
| }); |
| } |
| |
| /// When an implicitly-declared special member has to invoke more than one |
| /// base/field special member, conflicts may occur in the targets of these |
| /// members. For example, if one base's member __host__ and another's is |
| /// __device__, it's a conflict. |
| /// This function figures out if the given targets \param Target1 and |
| /// \param Target2 conflict, and if they do not it fills in |
| /// \param ResolvedTarget with a target that resolves for both calls. |
| /// \return true if there's a conflict, false otherwise. |
| static bool |
| resolveCalleeCUDATargetConflict(Sema::CUDAFunctionTarget Target1, |
| Sema::CUDAFunctionTarget Target2, |
| Sema::CUDAFunctionTarget *ResolvedTarget) { |
| // Only free functions and static member functions may be global. |
| assert(Target1 != Sema::CFT_Global); |
| assert(Target2 != Sema::CFT_Global); |
| |
| if (Target1 == Sema::CFT_HostDevice) { |
| *ResolvedTarget = Target2; |
| } else if (Target2 == Sema::CFT_HostDevice) { |
| *ResolvedTarget = Target1; |
| } else if (Target1 != Target2) { |
| return true; |
| } else { |
| *ResolvedTarget = Target1; |
| } |
| |
| return false; |
| } |
| |
| bool Sema::inferCUDATargetForImplicitSpecialMember(CXXRecordDecl *ClassDecl, |
| CXXSpecialMember CSM, |
| CXXMethodDecl *MemberDecl, |
| bool ConstRHS, |
| bool Diagnose) { |
| llvm::Optional<CUDAFunctionTarget> InferredTarget; |
| |
| // We're going to invoke special member lookup; mark that these special |
| // members are called from this one, and not from its caller. |
| ContextRAII MethodContext(*this, MemberDecl); |
| |
| // Look for special members in base classes that should be invoked from here. |
| // Infer the target of this member base on the ones it should call. |
| // Skip direct and indirect virtual bases for abstract classes. |
| llvm::SmallVector<const CXXBaseSpecifier *, 16> Bases; |
| for (const auto &B : ClassDecl->bases()) { |
| if (!B.isVirtual()) { |
| Bases.push_back(&B); |
| } |
| } |
| |
| if (!ClassDecl->isAbstract()) { |
| for (const auto &VB : ClassDecl->vbases()) { |
| Bases.push_back(&VB); |
| } |
| } |
| |
| for (const auto *B : Bases) { |
| const RecordType *BaseType = B->getType()->getAs<RecordType>(); |
| if (!BaseType) { |
| continue; |
| } |
| |
| CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(BaseType->getDecl()); |
| Sema::SpecialMemberOverloadResult *SMOR = |
| LookupSpecialMember(BaseClassDecl, CSM, |
| /* ConstArg */ ConstRHS, |
| /* VolatileArg */ false, |
| /* RValueThis */ false, |
| /* ConstThis */ false, |
| /* VolatileThis */ false); |
| |
| if (!SMOR || !SMOR->getMethod()) { |
| continue; |
| } |
| |
| CUDAFunctionTarget BaseMethodTarget = IdentifyCUDATarget(SMOR->getMethod()); |
| if (!InferredTarget.hasValue()) { |
| InferredTarget = BaseMethodTarget; |
| } else { |
| bool ResolutionError = resolveCalleeCUDATargetConflict( |
| InferredTarget.getValue(), BaseMethodTarget, |
| InferredTarget.getPointer()); |
| if (ResolutionError) { |
| if (Diagnose) { |
| Diag(ClassDecl->getLocation(), |
| diag::note_implicit_member_target_infer_collision) |
| << (unsigned)CSM << InferredTarget.getValue() << BaseMethodTarget; |
| } |
| MemberDecl->addAttr(CUDAInvalidTargetAttr::CreateImplicit(Context)); |
| return true; |
| } |
| } |
| } |
| |
| // Same as for bases, but now for special members of fields. |
| for (const auto *F : ClassDecl->fields()) { |
| if (F->isInvalidDecl()) { |
| continue; |
| } |
| |
| const RecordType *FieldType = |
| Context.getBaseElementType(F->getType())->getAs<RecordType>(); |
| if (!FieldType) { |
| continue; |
| } |
| |
| CXXRecordDecl *FieldRecDecl = cast<CXXRecordDecl>(FieldType->getDecl()); |
| Sema::SpecialMemberOverloadResult *SMOR = |
| LookupSpecialMember(FieldRecDecl, CSM, |
| /* ConstArg */ ConstRHS && !F->isMutable(), |
| /* VolatileArg */ false, |
| /* RValueThis */ false, |
| /* ConstThis */ false, |
| /* VolatileThis */ false); |
| |
| if (!SMOR || !SMOR->getMethod()) { |
| continue; |
| } |
| |
| CUDAFunctionTarget FieldMethodTarget = |
| IdentifyCUDATarget(SMOR->getMethod()); |
| if (!InferredTarget.hasValue()) { |
| InferredTarget = FieldMethodTarget; |
| } else { |
| bool ResolutionError = resolveCalleeCUDATargetConflict( |
| InferredTarget.getValue(), FieldMethodTarget, |
| InferredTarget.getPointer()); |
| if (ResolutionError) { |
| if (Diagnose) { |
| Diag(ClassDecl->getLocation(), |
| diag::note_implicit_member_target_infer_collision) |
| << (unsigned)CSM << InferredTarget.getValue() |
| << FieldMethodTarget; |
| } |
| MemberDecl->addAttr(CUDAInvalidTargetAttr::CreateImplicit(Context)); |
| return true; |
| } |
| } |
| } |
| |
| if (InferredTarget.hasValue()) { |
| if (InferredTarget.getValue() == CFT_Device) { |
| MemberDecl->addAttr(CUDADeviceAttr::CreateImplicit(Context)); |
| } else if (InferredTarget.getValue() == CFT_Host) { |
| MemberDecl->addAttr(CUDAHostAttr::CreateImplicit(Context)); |
| } else { |
| MemberDecl->addAttr(CUDADeviceAttr::CreateImplicit(Context)); |
| MemberDecl->addAttr(CUDAHostAttr::CreateImplicit(Context)); |
| } |
| } else { |
| // If no target was inferred, mark this member as __host__ __device__; |
| // it's the least restrictive option that can be invoked from any target. |
| MemberDecl->addAttr(CUDADeviceAttr::CreateImplicit(Context)); |
| MemberDecl->addAttr(CUDAHostAttr::CreateImplicit(Context)); |
| } |
| |
| return false; |
| } |
| |
| bool Sema::isEmptyCudaConstructor(SourceLocation Loc, CXXConstructorDecl *CD) { |
| if (!CD->isDefined() && CD->isTemplateInstantiation()) |
| InstantiateFunctionDefinition(Loc, CD->getFirstDecl()); |
| |
| // (E.2.3.1, CUDA 7.5) A constructor for a class type is considered |
| // empty at a point in the translation unit, if it is either a |
| // trivial constructor |
| if (CD->isTrivial()) |
| return true; |
| |
| // ... or it satisfies all of the following conditions: |
| // The constructor function has been defined. |
| // The constructor function has no parameters, |
| // and the function body is an empty compound statement. |
| if (!(CD->hasTrivialBody() && CD->getNumParams() == 0)) |
| return false; |
| |
| // Its class has no virtual functions and no virtual base classes. |
| if (CD->getParent()->isDynamicClass()) |
| return false; |
| |
| // The only form of initializer allowed is an empty constructor. |
| // This will recursively check all base classes and member initializers |
| if (!llvm::all_of(CD->inits(), [&](const CXXCtorInitializer *CI) { |
| if (const CXXConstructExpr *CE = |
| dyn_cast<CXXConstructExpr>(CI->getInit())) |
| return isEmptyCudaConstructor(Loc, CE->getConstructor()); |
| return false; |
| })) |
| return false; |
| |
| return true; |
| } |
| |
| bool Sema::isEmptyCudaDestructor(SourceLocation Loc, CXXDestructorDecl *DD) { |
| // No destructor -> no problem. |
| if (!DD) |
| return true; |
| |
| if (!DD->isDefined() && DD->isTemplateInstantiation()) |
| InstantiateFunctionDefinition(Loc, DD->getFirstDecl()); |
| |
| // (E.2.3.1, CUDA 7.5) A destructor for a class type is considered |
| // empty at a point in the translation unit, if it is either a |
| // trivial constructor |
| if (DD->isTrivial()) |
| return true; |
| |
| // ... or it satisfies all of the following conditions: |
| // The destructor function has been defined. |
| // and the function body is an empty compound statement. |
| if (!DD->hasTrivialBody()) |
| return false; |
| |
| const CXXRecordDecl *ClassDecl = DD->getParent(); |
| |
| // Its class has no virtual functions and no virtual base classes. |
| if (ClassDecl->isDynamicClass()) |
| return false; |
| |
| // Only empty destructors are allowed. This will recursively check |
| // destructors for all base classes... |
| if (!llvm::all_of(ClassDecl->bases(), [&](const CXXBaseSpecifier &BS) { |
| if (CXXRecordDecl *RD = BS.getType()->getAsCXXRecordDecl()) |
| return isEmptyCudaDestructor(Loc, RD->getDestructor()); |
| return true; |
| })) |
| return false; |
| |
| // ... and member fields. |
| if (!llvm::all_of(ClassDecl->fields(), [&](const FieldDecl *Field) { |
| if (CXXRecordDecl *RD = Field->getType() |
| ->getBaseElementTypeUnsafe() |
| ->getAsCXXRecordDecl()) |
| return isEmptyCudaDestructor(Loc, RD->getDestructor()); |
| return true; |
| })) |
| return false; |
| |
| return true; |
| } |
| |
| // With -fcuda-host-device-constexpr, an unattributed constexpr function is |
| // treated as implicitly __host__ __device__, unless: |
| // * it is a variadic function (device-side variadic functions are not |
| // allowed), or |
| // * a __device__ function with this signature was already declared, in which |
| // case in which case we output an error, unless the __device__ decl is in a |
| // system header, in which case we leave the constexpr function unattributed. |
| void Sema::maybeAddCUDAHostDeviceAttrs(Scope *S, FunctionDecl *NewD, |
| const LookupResult &Previous) { |
| assert(getLangOpts().CUDA && "May be called only for CUDA compilations."); |
| if (!getLangOpts().CUDAHostDeviceConstexpr || !NewD->isConstexpr() || |
| NewD->isVariadic() || NewD->hasAttr<CUDAHostAttr>() || |
| NewD->hasAttr<CUDADeviceAttr>() || NewD->hasAttr<CUDAGlobalAttr>()) |
| return; |
| |
| // Is D a __device__ function with the same signature as NewD, ignoring CUDA |
| // attributes? |
| auto IsMatchingDeviceFn = [&](NamedDecl *D) { |
| if (UsingShadowDecl *Using = dyn_cast<UsingShadowDecl>(D)) |
| D = Using->getTargetDecl(); |
| FunctionDecl *OldD = D->getAsFunction(); |
| return OldD && OldD->hasAttr<CUDADeviceAttr>() && |
| !OldD->hasAttr<CUDAHostAttr>() && |
| !IsOverload(NewD, OldD, /* UseMemberUsingDeclRules = */ false, |
| /* ConsiderCudaAttrs = */ false); |
| }; |
| auto It = llvm::find_if(Previous, IsMatchingDeviceFn); |
| if (It != Previous.end()) { |
| // We found a __device__ function with the same name and signature as NewD |
| // (ignoring CUDA attrs). This is an error unless that function is defined |
| // in a system header, in which case we simply return without making NewD |
| // host+device. |
| NamedDecl *Match = *It; |
| if (!getSourceManager().isInSystemHeader(Match->getLocation())) { |
| Diag(NewD->getLocation(), |
| diag::err_cuda_unattributed_constexpr_cannot_overload_device) |
| << NewD->getName(); |
| Diag(Match->getLocation(), |
| diag::note_cuda_conflicting_device_function_declared_here); |
| } |
| return; |
| } |
| |
| NewD->addAttr(CUDAHostAttr::CreateImplicit(Context)); |
| NewD->addAttr(CUDADeviceAttr::CreateImplicit(Context)); |
| } |
| |
| bool Sema::CheckCUDACall(SourceLocation Loc, FunctionDecl *Callee) { |
| assert(getLangOpts().CUDA && |
| "Should only be called during CUDA compilation."); |
| assert(Callee && "Callee may not be null."); |
| FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext); |
| if (!Caller) |
| return true; |
| |
| Sema::CUDAFunctionPreference Pref = IdentifyCUDAPreference(Caller, Callee); |
| if (Pref == Sema::CFP_Never) { |
| Diag(Loc, diag::err_ref_bad_target) << IdentifyCUDATarget(Callee) << Callee |
| << IdentifyCUDATarget(Caller); |
| Diag(Callee->getLocation(), diag::note_previous_decl) << Callee; |
| return false; |
| } |
| if (Pref == Sema::CFP_WrongSide) { |
| // We have to do this odd dance to create our PartialDiagnostic because we |
| // want its storage to be allocated with operator new, not in an arena. |
| PartialDiagnostic ErrPD{PartialDiagnostic::NullDiagnostic()}; |
| ErrPD.Reset(diag::err_ref_bad_target); |
| ErrPD << IdentifyCUDATarget(Callee) << Callee << IdentifyCUDATarget(Caller); |
| Caller->addDeferredDiag({Loc, std::move(ErrPD)}); |
| |
| PartialDiagnostic NotePD{PartialDiagnostic::NullDiagnostic()}; |
| NotePD.Reset(diag::note_previous_decl); |
| NotePD << Callee; |
| Caller->addDeferredDiag({Callee->getLocation(), std::move(NotePD)}); |
| |
| // This is not immediately an error, so return true. The deferred errors |
| // will be emitted if and when Caller is codegen'ed. |
| return true; |
| } |
| return true; |
| } |
