| //===--- SemaStmtAttr.cpp - Statement Attribute Handling ------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements stmt-related attribute processing. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Sema/SemaInternal.h" |
| #include "clang/AST/ASTContext.h" |
| #include "clang/Basic/SourceManager.h" |
| #include "clang/Sema/DelayedDiagnostic.h" |
| #include "clang/Sema/Lookup.h" |
| #include "clang/Sema/LoopHint.h" |
| #include "clang/Sema/ScopeInfo.h" |
| #include "llvm/ADT/StringExtras.h" |
| |
| using namespace clang; |
| using namespace sema; |
| |
| static Attr *handleFallThroughAttr(Sema &S, Stmt *St, const ParsedAttr &A, |
| SourceRange Range) { |
| FallThroughAttr Attr(A.getRange(), S.Context, |
| A.getAttributeSpellingListIndex()); |
| if (!isa<NullStmt>(St)) { |
| S.Diag(A.getRange().getBegin(), diag::err_fallthrough_attr_wrong_target) |
| << Attr.getSpelling() << St->getLocStart(); |
| if (isa<SwitchCase>(St)) { |
| SourceLocation L = S.getLocForEndOfToken(Range.getEnd()); |
| S.Diag(L, diag::note_fallthrough_insert_semi_fixit) |
| << FixItHint::CreateInsertion(L, ";"); |
| } |
| return nullptr; |
| } |
| auto *FnScope = S.getCurFunction(); |
| if (FnScope->SwitchStack.empty()) { |
| S.Diag(A.getRange().getBegin(), diag::err_fallthrough_attr_outside_switch); |
| return nullptr; |
| } |
| |
| // If this is spelled as the standard C++17 attribute, but not in C++17, warn |
| // about using it as an extension. |
| if (!S.getLangOpts().CPlusPlus17 && A.isCXX11Attribute() && |
| !A.getScopeName()) |
| S.Diag(A.getLoc(), diag::ext_cxx17_attr) << A.getName(); |
| |
| FnScope->setHasFallthroughStmt(); |
| return ::new (S.Context) auto(Attr); |
| } |
| |
| static Attr *handleSuppressAttr(Sema &S, Stmt *St, const ParsedAttr &A, |
| SourceRange Range) { |
| if (A.getNumArgs() < 1) { |
| S.Diag(A.getLoc(), diag::err_attribute_too_few_arguments) |
| << A.getName() << 1; |
| return nullptr; |
| } |
| |
| std::vector<StringRef> DiagnosticIdentifiers; |
| for (unsigned I = 0, E = A.getNumArgs(); I != E; ++I) { |
| StringRef RuleName; |
| |
| if (!S.checkStringLiteralArgumentAttr(A, I, RuleName, nullptr)) |
| return nullptr; |
| |
| // FIXME: Warn if the rule name is unknown. This is tricky because only |
| // clang-tidy knows about available rules. |
| DiagnosticIdentifiers.push_back(RuleName); |
| } |
| |
| return ::new (S.Context) SuppressAttr( |
| A.getRange(), S.Context, DiagnosticIdentifiers.data(), |
| DiagnosticIdentifiers.size(), A.getAttributeSpellingListIndex()); |
| } |
| |
| static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const ParsedAttr &A, |
| SourceRange) { |
| IdentifierLoc *PragmaNameLoc = A.getArgAsIdent(0); |
| IdentifierLoc *OptionLoc = A.getArgAsIdent(1); |
| IdentifierLoc *StateLoc = A.getArgAsIdent(2); |
| Expr *ValueExpr = A.getArgAsExpr(3); |
| |
| bool PragmaUnroll = PragmaNameLoc->Ident->getName() == "unroll"; |
| bool PragmaNoUnroll = PragmaNameLoc->Ident->getName() == "nounroll"; |
| if (St->getStmtClass() != Stmt::DoStmtClass && |
| St->getStmtClass() != Stmt::ForStmtClass && |
| St->getStmtClass() != Stmt::CXXForRangeStmtClass && |
| St->getStmtClass() != Stmt::WhileStmtClass) { |
| const char *Pragma = |
| llvm::StringSwitch<const char *>(PragmaNameLoc->Ident->getName()) |
| .Case("unroll", "#pragma unroll") |
| .Case("nounroll", "#pragma nounroll") |
| .Default("#pragma clang loop"); |
| S.Diag(St->getLocStart(), diag::err_pragma_loop_precedes_nonloop) << Pragma; |
| return nullptr; |
| } |
| |
| LoopHintAttr::Spelling Spelling = |
| LoopHintAttr::Spelling(A.getAttributeSpellingListIndex()); |
| LoopHintAttr::OptionType Option; |
| LoopHintAttr::LoopHintState State; |
| if (PragmaNoUnroll) { |
| // #pragma nounroll |
| Option = LoopHintAttr::Unroll; |
| State = LoopHintAttr::Disable; |
| } else if (PragmaUnroll) { |
| if (ValueExpr) { |
| // #pragma unroll N |
| Option = LoopHintAttr::UnrollCount; |
| State = LoopHintAttr::Numeric; |
| } else { |
| // #pragma unroll |
| Option = LoopHintAttr::Unroll; |
| State = LoopHintAttr::Enable; |
| } |
| } else { |
| // #pragma clang loop ... |
| assert(OptionLoc && OptionLoc->Ident && |
| "Attribute must have valid option info."); |
| Option = llvm::StringSwitch<LoopHintAttr::OptionType>( |
| OptionLoc->Ident->getName()) |
| .Case("vectorize", LoopHintAttr::Vectorize) |
| .Case("vectorize_width", LoopHintAttr::VectorizeWidth) |
| .Case("interleave", LoopHintAttr::Interleave) |
| .Case("interleave_count", LoopHintAttr::InterleaveCount) |
| .Case("unroll", LoopHintAttr::Unroll) |
| .Case("unroll_count", LoopHintAttr::UnrollCount) |
| .Case("distribute", LoopHintAttr::Distribute) |
| .Default(LoopHintAttr::Vectorize); |
| if (Option == LoopHintAttr::VectorizeWidth || |
| Option == LoopHintAttr::InterleaveCount || |
| Option == LoopHintAttr::UnrollCount) { |
| assert(ValueExpr && "Attribute must have a valid value expression."); |
| if (S.CheckLoopHintExpr(ValueExpr, St->getLocStart())) |
| return nullptr; |
| State = LoopHintAttr::Numeric; |
| } else if (Option == LoopHintAttr::Vectorize || |
| Option == LoopHintAttr::Interleave || |
| Option == LoopHintAttr::Unroll || |
| Option == LoopHintAttr::Distribute) { |
| assert(StateLoc && StateLoc->Ident && "Loop hint must have an argument"); |
| if (StateLoc->Ident->isStr("disable")) |
| State = LoopHintAttr::Disable; |
| else if (StateLoc->Ident->isStr("assume_safety")) |
| State = LoopHintAttr::AssumeSafety; |
| else if (StateLoc->Ident->isStr("full")) |
| State = LoopHintAttr::Full; |
| else if (StateLoc->Ident->isStr("enable")) |
| State = LoopHintAttr::Enable; |
| else |
| llvm_unreachable("bad loop hint argument"); |
| } else |
| llvm_unreachable("bad loop hint"); |
| } |
| |
| return LoopHintAttr::CreateImplicit(S.Context, Spelling, Option, State, |
| ValueExpr, A.getRange()); |
| } |
| |
| static void |
| CheckForIncompatibleAttributes(Sema &S, |
| const SmallVectorImpl<const Attr *> &Attrs) { |
| // There are 4 categories of loop hints attributes: vectorize, interleave, |
| // unroll and distribute. Except for distribute they come in two variants: a |
| // state form and a numeric form. The state form selectively |
| // defaults/enables/disables the transformation for the loop (for unroll, |
| // default indicates full unrolling rather than enabling the transformation). |
| // The numeric form form provides an integer hint (for example, unroll count) |
| // to the transformer. The following array accumulates the hints encountered |
| // while iterating through the attributes to check for compatibility. |
| struct { |
| const LoopHintAttr *StateAttr; |
| const LoopHintAttr *NumericAttr; |
| } HintAttrs[] = {{nullptr, nullptr}, |
| {nullptr, nullptr}, |
| {nullptr, nullptr}, |
| {nullptr, nullptr}}; |
| |
| for (const auto *I : Attrs) { |
| const LoopHintAttr *LH = dyn_cast<LoopHintAttr>(I); |
| |
| // Skip non loop hint attributes |
| if (!LH) |
| continue; |
| |
| LoopHintAttr::OptionType Option = LH->getOption(); |
| enum { Vectorize, Interleave, Unroll, Distribute } Category; |
| switch (Option) { |
| case LoopHintAttr::Vectorize: |
| case LoopHintAttr::VectorizeWidth: |
| Category = Vectorize; |
| break; |
| case LoopHintAttr::Interleave: |
| case LoopHintAttr::InterleaveCount: |
| Category = Interleave; |
| break; |
| case LoopHintAttr::Unroll: |
| case LoopHintAttr::UnrollCount: |
| Category = Unroll; |
| break; |
| case LoopHintAttr::Distribute: |
| // Perform the check for duplicated 'distribute' hints. |
| Category = Distribute; |
| break; |
| }; |
| |
| auto &CategoryState = HintAttrs[Category]; |
| const LoopHintAttr *PrevAttr; |
| if (Option == LoopHintAttr::Vectorize || |
| Option == LoopHintAttr::Interleave || Option == LoopHintAttr::Unroll || |
| Option == LoopHintAttr::Distribute) { |
| // Enable|Disable|AssumeSafety hint. For example, vectorize(enable). |
| PrevAttr = CategoryState.StateAttr; |
| CategoryState.StateAttr = LH; |
| } else { |
| // Numeric hint. For example, vectorize_width(8). |
| PrevAttr = CategoryState.NumericAttr; |
| CategoryState.NumericAttr = LH; |
| } |
| |
| PrintingPolicy Policy(S.Context.getLangOpts()); |
| SourceLocation OptionLoc = LH->getRange().getBegin(); |
| if (PrevAttr) |
| // Cannot specify same type of attribute twice. |
| S.Diag(OptionLoc, diag::err_pragma_loop_compatibility) |
| << /*Duplicate=*/true << PrevAttr->getDiagnosticName(Policy) |
| << LH->getDiagnosticName(Policy); |
| |
| if (CategoryState.StateAttr && CategoryState.NumericAttr && |
| (Category == Unroll || |
| CategoryState.StateAttr->getState() == LoopHintAttr::Disable)) { |
| // Disable hints are not compatible with numeric hints of the same |
| // category. As a special case, numeric unroll hints are also not |
| // compatible with enable or full form of the unroll pragma because these |
| // directives indicate full unrolling. |
| S.Diag(OptionLoc, diag::err_pragma_loop_compatibility) |
| << /*Duplicate=*/false |
| << CategoryState.StateAttr->getDiagnosticName(Policy) |
| << CategoryState.NumericAttr->getDiagnosticName(Policy); |
| } |
| } |
| } |
| |
| static Attr *handleOpenCLUnrollHint(Sema &S, Stmt *St, const ParsedAttr &A, |
| SourceRange Range) { |
| // Although the feature was introduced only in OpenCL C v2.0 s6.11.5, it's |
| // useful for OpenCL 1.x too and doesn't require HW support. |
| // opencl_unroll_hint can have 0 arguments (compiler |
| // determines unrolling factor) or 1 argument (the unroll factor provided |
| // by the user). |
| |
| unsigned NumArgs = A.getNumArgs(); |
| |
| if (NumArgs > 1) { |
| S.Diag(A.getLoc(), diag::err_attribute_too_many_arguments) << A.getName() |
| << 1; |
| return nullptr; |
| } |
| |
| unsigned UnrollFactor = 0; |
| |
| if (NumArgs == 1) { |
| Expr *E = A.getArgAsExpr(0); |
| llvm::APSInt ArgVal(32); |
| |
| if (!E->isIntegerConstantExpr(ArgVal, S.Context)) { |
| S.Diag(A.getLoc(), diag::err_attribute_argument_type) |
| << A.getName() << AANT_ArgumentIntegerConstant << E->getSourceRange(); |
| return nullptr; |
| } |
| |
| int Val = ArgVal.getSExtValue(); |
| |
| if (Val <= 0) { |
| S.Diag(A.getRange().getBegin(), |
| diag::err_attribute_requires_positive_integer) |
| << A.getName(); |
| return nullptr; |
| } |
| UnrollFactor = Val; |
| } |
| |
| return OpenCLUnrollHintAttr::CreateImplicit(S.Context, UnrollFactor); |
| } |
| |
| static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const ParsedAttr &A, |
| SourceRange Range) { |
| switch (A.getKind()) { |
| case ParsedAttr::UnknownAttribute: |
| S.Diag(A.getLoc(), A.isDeclspecAttribute() ? |
| diag::warn_unhandled_ms_attribute_ignored : |
| diag::warn_unknown_attribute_ignored) << A.getName(); |
| return nullptr; |
| case ParsedAttr::AT_FallThrough: |
| return handleFallThroughAttr(S, St, A, Range); |
| case ParsedAttr::AT_LoopHint: |
| return handleLoopHintAttr(S, St, A, Range); |
| case ParsedAttr::AT_OpenCLUnrollHint: |
| return handleOpenCLUnrollHint(S, St, A, Range); |
| case ParsedAttr::AT_Suppress: |
| return handleSuppressAttr(S, St, A, Range); |
| default: |
| // if we're here, then we parsed a known attribute, but didn't recognize |
| // it as a statement attribute => it is declaration attribute |
| S.Diag(A.getRange().getBegin(), diag::err_decl_attribute_invalid_on_stmt) |
| << A.getName() << St->getLocStart(); |
| return nullptr; |
| } |
| } |
| |
| StmtResult Sema::ProcessStmtAttributes(Stmt *S, |
| const ParsedAttributesView &AttrList, |
| SourceRange Range) { |
| SmallVector<const Attr*, 8> Attrs; |
| for (const ParsedAttr &AL : AttrList) { |
| if (Attr *a = ProcessStmtAttribute(*this, S, AL, Range)) |
| Attrs.push_back(a); |
| } |
| |
| CheckForIncompatibleAttributes(*this, Attrs); |
| |
| if (Attrs.empty()) |
| return S; |
| |
| return ActOnAttributedStmt(Range.getBegin(), Attrs, S); |
| } |
