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-rw-r--r--clang/lib/Sema/SemaStmtAttr.cpp362
1 files changed, 362 insertions, 0 deletions
diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
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index 000000000000..3d91893b4065
--- /dev/null
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
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+//===--- SemaStmtAttr.cpp - Statement Attribute Handling ------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// 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/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(S.Context, A);
+ if (!isa<NullStmt>(St)) {
+ S.Diag(A.getRange().getBegin(), diag::err_fallthrough_attr_wrong_target)
+ << Attr.getSpelling() << St->getBeginLoc();
+ 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;
+
+ FnScope->setHasFallthroughStmt();
+ return ::new (S.Context) FallThroughAttr(S.Context, A);
+}
+
+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 << 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(
+ S.Context, A, DiagnosticIdentifiers.data(), DiagnosticIdentifiers.size());
+}
+
+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);
+
+ StringRef PragmaName =
+ llvm::StringSwitch<StringRef>(PragmaNameLoc->Ident->getName())
+ .Cases("unroll", "nounroll", "unroll_and_jam", "nounroll_and_jam",
+ PragmaNameLoc->Ident->getName())
+ .Default("clang loop");
+
+ if (St->getStmtClass() != Stmt::DoStmtClass &&
+ St->getStmtClass() != Stmt::ForStmtClass &&
+ St->getStmtClass() != Stmt::CXXForRangeStmtClass &&
+ St->getStmtClass() != Stmt::WhileStmtClass) {
+ std::string Pragma = "#pragma " + std::string(PragmaName);
+ S.Diag(St->getBeginLoc(), diag::err_pragma_loop_precedes_nonloop) << Pragma;
+ return nullptr;
+ }
+
+ LoopHintAttr::OptionType Option;
+ LoopHintAttr::LoopHintState State;
+
+ auto SetHints = [&Option, &State](LoopHintAttr::OptionType O,
+ LoopHintAttr::LoopHintState S) {
+ Option = O;
+ State = S;
+ };
+
+ if (PragmaName == "nounroll") {
+ SetHints(LoopHintAttr::Unroll, LoopHintAttr::Disable);
+ } else if (PragmaName == "unroll") {
+ // #pragma unroll N
+ if (ValueExpr)
+ SetHints(LoopHintAttr::UnrollCount, LoopHintAttr::Numeric);
+ else
+ SetHints(LoopHintAttr::Unroll, LoopHintAttr::Enable);
+ } else if (PragmaName == "nounroll_and_jam") {
+ SetHints(LoopHintAttr::UnrollAndJam, LoopHintAttr::Disable);
+ } else if (PragmaName == "unroll_and_jam") {
+ // #pragma unroll_and_jam N
+ if (ValueExpr)
+ SetHints(LoopHintAttr::UnrollAndJamCount, LoopHintAttr::Numeric);
+ else
+ SetHints(LoopHintAttr::UnrollAndJam, 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("vectorize_predicate", LoopHintAttr::VectorizePredicate)
+ .Case("interleave_count", LoopHintAttr::InterleaveCount)
+ .Case("unroll", LoopHintAttr::Unroll)
+ .Case("unroll_count", LoopHintAttr::UnrollCount)
+ .Case("pipeline", LoopHintAttr::PipelineDisabled)
+ .Case("pipeline_initiation_interval",
+ LoopHintAttr::PipelineInitiationInterval)
+ .Case("distribute", LoopHintAttr::Distribute)
+ .Default(LoopHintAttr::Vectorize);
+ if (Option == LoopHintAttr::VectorizeWidth ||
+ Option == LoopHintAttr::InterleaveCount ||
+ Option == LoopHintAttr::UnrollCount ||
+ Option == LoopHintAttr::PipelineInitiationInterval) {
+ assert(ValueExpr && "Attribute must have a valid value expression.");
+ if (S.CheckLoopHintExpr(ValueExpr, St->getBeginLoc()))
+ return nullptr;
+ State = LoopHintAttr::Numeric;
+ } else if (Option == LoopHintAttr::Vectorize ||
+ Option == LoopHintAttr::Interleave ||
+ Option == LoopHintAttr::VectorizePredicate ||
+ Option == LoopHintAttr::Unroll ||
+ Option == LoopHintAttr::Distribute ||
+ Option == LoopHintAttr::PipelineDisabled) {
+ 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, Option, State, ValueExpr, A);
+}
+
+static void
+CheckForIncompatibleAttributes(Sema &S,
+ const SmallVectorImpl<const Attr *> &Attrs) {
+ // There are 6 categories of loop hints attributes: vectorize, interleave,
+ // unroll, unroll_and_jam, pipeline 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}, {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,
+ UnrollAndJam,
+ Distribute,
+ Pipeline,
+ VectorizePredicate
+ } 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::UnrollAndJam:
+ case LoopHintAttr::UnrollAndJamCount:
+ Category = UnrollAndJam;
+ break;
+ case LoopHintAttr::Distribute:
+ // Perform the check for duplicated 'distribute' hints.
+ Category = Distribute;
+ break;
+ case LoopHintAttr::PipelineDisabled:
+ case LoopHintAttr::PipelineInitiationInterval:
+ Category = Pipeline;
+ break;
+ case LoopHintAttr::VectorizePredicate:
+ Category = VectorizePredicate;
+ break;
+ };
+
+ assert(Category < sizeof(HintAttrs) / sizeof(HintAttrs[0]));
+ auto &CategoryState = HintAttrs[Category];
+ const LoopHintAttr *PrevAttr;
+ if (Option == LoopHintAttr::Vectorize ||
+ Option == LoopHintAttr::Interleave || Option == LoopHintAttr::Unroll ||
+ Option == LoopHintAttr::UnrollAndJam ||
+ Option == LoopHintAttr::VectorizePredicate ||
+ Option == LoopHintAttr::PipelineDisabled ||
+ 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 || Category == UnrollAndJam ||
+ 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 << 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 << 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 << /* positive */ 0;
+ 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()
+ ? (unsigned)diag::warn_unhandled_ms_attribute_ignored
+ : (unsigned)diag::warn_unknown_attribute_ignored)
+ << A;
+ 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 << St->getBeginLoc();
+ 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);
+}
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