1 //===--- SemaStmtAttr.cpp - Statement Attribute Handling ------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements stmt-related attribute processing.
12 //===----------------------------------------------------------------------===//
14 #include "clang/Sema/SemaInternal.h"
15 #include "clang/AST/ASTContext.h"
16 #include "clang/Basic/SourceManager.h"
17 #include "clang/Sema/DelayedDiagnostic.h"
18 #include "clang/Sema/Lookup.h"
19 #include "clang/Sema/LoopHint.h"
20 #include "clang/Sema/ScopeInfo.h"
21 #include "llvm/ADT/StringExtras.h"
23 using namespace clang;
26 static Attr *handleFallThroughAttr(Sema &S, Stmt *St, const ParsedAttr &A,
28 FallThroughAttr Attr(A.getRange(), S.Context,
29 A.getAttributeSpellingListIndex());
30 if (!isa<NullStmt>(St)) {
31 S.Diag(A.getRange().getBegin(), diag::err_fallthrough_attr_wrong_target)
32 << Attr.getSpelling() << St->getLocStart();
33 if (isa<SwitchCase>(St)) {
34 SourceLocation L = S.getLocForEndOfToken(Range.getEnd());
35 S.Diag(L, diag::note_fallthrough_insert_semi_fixit)
36 << FixItHint::CreateInsertion(L, ";");
40 auto *FnScope = S.getCurFunction();
41 if (FnScope->SwitchStack.empty()) {
42 S.Diag(A.getRange().getBegin(), diag::err_fallthrough_attr_outside_switch);
46 // If this is spelled as the standard C++17 attribute, but not in C++17, warn
47 // about using it as an extension.
48 if (!S.getLangOpts().CPlusPlus17 && A.isCXX11Attribute() &&
50 S.Diag(A.getLoc(), diag::ext_cxx17_attr) << A.getName();
52 FnScope->setHasFallthroughStmt();
53 return ::new (S.Context) auto(Attr);
56 static Attr *handleSuppressAttr(Sema &S, Stmt *St, const ParsedAttr &A,
58 if (A.getNumArgs() < 1) {
59 S.Diag(A.getLoc(), diag::err_attribute_too_few_arguments)
64 std::vector<StringRef> DiagnosticIdentifiers;
65 for (unsigned I = 0, E = A.getNumArgs(); I != E; ++I) {
68 if (!S.checkStringLiteralArgumentAttr(A, I, RuleName, nullptr))
71 // FIXME: Warn if the rule name is unknown. This is tricky because only
72 // clang-tidy knows about available rules.
73 DiagnosticIdentifiers.push_back(RuleName);
76 return ::new (S.Context) SuppressAttr(
77 A.getRange(), S.Context, DiagnosticIdentifiers.data(),
78 DiagnosticIdentifiers.size(), A.getAttributeSpellingListIndex());
81 static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const ParsedAttr &A,
83 IdentifierLoc *PragmaNameLoc = A.getArgAsIdent(0);
84 IdentifierLoc *OptionLoc = A.getArgAsIdent(1);
85 IdentifierLoc *StateLoc = A.getArgAsIdent(2);
86 Expr *ValueExpr = A.getArgAsExpr(3);
88 bool PragmaUnroll = PragmaNameLoc->Ident->getName() == "unroll";
89 bool PragmaNoUnroll = PragmaNameLoc->Ident->getName() == "nounroll";
90 if (St->getStmtClass() != Stmt::DoStmtClass &&
91 St->getStmtClass() != Stmt::ForStmtClass &&
92 St->getStmtClass() != Stmt::CXXForRangeStmtClass &&
93 St->getStmtClass() != Stmt::WhileStmtClass) {
95 llvm::StringSwitch<const char *>(PragmaNameLoc->Ident->getName())
96 .Case("unroll", "#pragma unroll")
97 .Case("nounroll", "#pragma nounroll")
98 .Default("#pragma clang loop");
99 S.Diag(St->getLocStart(), diag::err_pragma_loop_precedes_nonloop) << Pragma;
103 LoopHintAttr::Spelling Spelling =
104 LoopHintAttr::Spelling(A.getAttributeSpellingListIndex());
105 LoopHintAttr::OptionType Option;
106 LoopHintAttr::LoopHintState State;
107 if (PragmaNoUnroll) {
109 Option = LoopHintAttr::Unroll;
110 State = LoopHintAttr::Disable;
111 } else if (PragmaUnroll) {
114 Option = LoopHintAttr::UnrollCount;
115 State = LoopHintAttr::Numeric;
118 Option = LoopHintAttr::Unroll;
119 State = LoopHintAttr::Enable;
122 // #pragma clang loop ...
123 assert(OptionLoc && OptionLoc->Ident &&
124 "Attribute must have valid option info.");
125 Option = llvm::StringSwitch<LoopHintAttr::OptionType>(
126 OptionLoc->Ident->getName())
127 .Case("vectorize", LoopHintAttr::Vectorize)
128 .Case("vectorize_width", LoopHintAttr::VectorizeWidth)
129 .Case("interleave", LoopHintAttr::Interleave)
130 .Case("interleave_count", LoopHintAttr::InterleaveCount)
131 .Case("unroll", LoopHintAttr::Unroll)
132 .Case("unroll_count", LoopHintAttr::UnrollCount)
133 .Case("distribute", LoopHintAttr::Distribute)
134 .Default(LoopHintAttr::Vectorize);
135 if (Option == LoopHintAttr::VectorizeWidth ||
136 Option == LoopHintAttr::InterleaveCount ||
137 Option == LoopHintAttr::UnrollCount) {
138 assert(ValueExpr && "Attribute must have a valid value expression.");
139 if (S.CheckLoopHintExpr(ValueExpr, St->getLocStart()))
141 State = LoopHintAttr::Numeric;
142 } else if (Option == LoopHintAttr::Vectorize ||
143 Option == LoopHintAttr::Interleave ||
144 Option == LoopHintAttr::Unroll ||
145 Option == LoopHintAttr::Distribute) {
146 assert(StateLoc && StateLoc->Ident && "Loop hint must have an argument");
147 if (StateLoc->Ident->isStr("disable"))
148 State = LoopHintAttr::Disable;
149 else if (StateLoc->Ident->isStr("assume_safety"))
150 State = LoopHintAttr::AssumeSafety;
151 else if (StateLoc->Ident->isStr("full"))
152 State = LoopHintAttr::Full;
153 else if (StateLoc->Ident->isStr("enable"))
154 State = LoopHintAttr::Enable;
156 llvm_unreachable("bad loop hint argument");
158 llvm_unreachable("bad loop hint");
161 return LoopHintAttr::CreateImplicit(S.Context, Spelling, Option, State,
162 ValueExpr, A.getRange());
166 CheckForIncompatibleAttributes(Sema &S,
167 const SmallVectorImpl<const Attr *> &Attrs) {
168 // There are 4 categories of loop hints attributes: vectorize, interleave,
169 // unroll and distribute. Except for distribute they come in two variants: a
170 // state form and a numeric form. The state form selectively
171 // defaults/enables/disables the transformation for the loop (for unroll,
172 // default indicates full unrolling rather than enabling the transformation).
173 // The numeric form form provides an integer hint (for example, unroll count)
174 // to the transformer. The following array accumulates the hints encountered
175 // while iterating through the attributes to check for compatibility.
177 const LoopHintAttr *StateAttr;
178 const LoopHintAttr *NumericAttr;
179 } HintAttrs[] = {{nullptr, nullptr},
184 for (const auto *I : Attrs) {
185 const LoopHintAttr *LH = dyn_cast<LoopHintAttr>(I);
187 // Skip non loop hint attributes
191 LoopHintAttr::OptionType Option = LH->getOption();
192 enum { Vectorize, Interleave, Unroll, Distribute } Category;
194 case LoopHintAttr::Vectorize:
195 case LoopHintAttr::VectorizeWidth:
196 Category = Vectorize;
198 case LoopHintAttr::Interleave:
199 case LoopHintAttr::InterleaveCount:
200 Category = Interleave;
202 case LoopHintAttr::Unroll:
203 case LoopHintAttr::UnrollCount:
206 case LoopHintAttr::Distribute:
207 // Perform the check for duplicated 'distribute' hints.
208 Category = Distribute;
212 auto &CategoryState = HintAttrs[Category];
213 const LoopHintAttr *PrevAttr;
214 if (Option == LoopHintAttr::Vectorize ||
215 Option == LoopHintAttr::Interleave || Option == LoopHintAttr::Unroll ||
216 Option == LoopHintAttr::Distribute) {
217 // Enable|Disable|AssumeSafety hint. For example, vectorize(enable).
218 PrevAttr = CategoryState.StateAttr;
219 CategoryState.StateAttr = LH;
221 // Numeric hint. For example, vectorize_width(8).
222 PrevAttr = CategoryState.NumericAttr;
223 CategoryState.NumericAttr = LH;
226 PrintingPolicy Policy(S.Context.getLangOpts());
227 SourceLocation OptionLoc = LH->getRange().getBegin();
229 // Cannot specify same type of attribute twice.
230 S.Diag(OptionLoc, diag::err_pragma_loop_compatibility)
231 << /*Duplicate=*/true << PrevAttr->getDiagnosticName(Policy)
232 << LH->getDiagnosticName(Policy);
234 if (CategoryState.StateAttr && CategoryState.NumericAttr &&
235 (Category == Unroll ||
236 CategoryState.StateAttr->getState() == LoopHintAttr::Disable)) {
237 // Disable hints are not compatible with numeric hints of the same
238 // category. As a special case, numeric unroll hints are also not
239 // compatible with enable or full form of the unroll pragma because these
240 // directives indicate full unrolling.
241 S.Diag(OptionLoc, diag::err_pragma_loop_compatibility)
242 << /*Duplicate=*/false
243 << CategoryState.StateAttr->getDiagnosticName(Policy)
244 << CategoryState.NumericAttr->getDiagnosticName(Policy);
249 static Attr *handleOpenCLUnrollHint(Sema &S, Stmt *St, const ParsedAttr &A,
251 // Although the feature was introduced only in OpenCL C v2.0 s6.11.5, it's
252 // useful for OpenCL 1.x too and doesn't require HW support.
253 // opencl_unroll_hint can have 0 arguments (compiler
254 // determines unrolling factor) or 1 argument (the unroll factor provided
257 unsigned NumArgs = A.getNumArgs();
260 S.Diag(A.getLoc(), diag::err_attribute_too_many_arguments) << A.getName()
265 unsigned UnrollFactor = 0;
268 Expr *E = A.getArgAsExpr(0);
269 llvm::APSInt ArgVal(32);
271 if (!E->isIntegerConstantExpr(ArgVal, S.Context)) {
272 S.Diag(A.getLoc(), diag::err_attribute_argument_type)
273 << A.getName() << AANT_ArgumentIntegerConstant << E->getSourceRange();
277 int Val = ArgVal.getSExtValue();
280 S.Diag(A.getRange().getBegin(),
281 diag::err_attribute_requires_positive_integer)
288 return OpenCLUnrollHintAttr::CreateImplicit(S.Context, UnrollFactor);
291 static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const ParsedAttr &A,
293 switch (A.getKind()) {
294 case ParsedAttr::UnknownAttribute:
295 S.Diag(A.getLoc(), A.isDeclspecAttribute() ?
296 diag::warn_unhandled_ms_attribute_ignored :
297 diag::warn_unknown_attribute_ignored) << A.getName();
299 case ParsedAttr::AT_FallThrough:
300 return handleFallThroughAttr(S, St, A, Range);
301 case ParsedAttr::AT_LoopHint:
302 return handleLoopHintAttr(S, St, A, Range);
303 case ParsedAttr::AT_OpenCLUnrollHint:
304 return handleOpenCLUnrollHint(S, St, A, Range);
305 case ParsedAttr::AT_Suppress:
306 return handleSuppressAttr(S, St, A, Range);
308 // if we're here, then we parsed a known attribute, but didn't recognize
309 // it as a statement attribute => it is declaration attribute
310 S.Diag(A.getRange().getBegin(), diag::err_decl_attribute_invalid_on_stmt)
311 << A.getName() << St->getLocStart();
316 StmtResult Sema::ProcessStmtAttributes(Stmt *S,
317 const ParsedAttributesView &AttrList,
319 SmallVector<const Attr*, 8> Attrs;
320 for (const ParsedAttr &AL : AttrList) {
321 if (Attr *a = ProcessStmtAttribute(*this, S, AL, Range))
325 CheckForIncompatibleAttributes(*this, Attrs);
330 return ActOnAttributedStmt(Range.getBegin(), Attrs, S);