1 //===--- SemaStmtAsm.cpp - Semantic Analysis for Asm Statements -----------===//
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 semantic analysis for inline asm statements.
12 //===----------------------------------------------------------------------===//
14 #include "clang/AST/ExprCXX.h"
15 #include "clang/AST/RecordLayout.h"
16 #include "clang/AST/TypeLoc.h"
17 #include "clang/Basic/TargetInfo.h"
18 #include "clang/Lex/Preprocessor.h"
19 #include "clang/Sema/Initialization.h"
20 #include "clang/Sema/Lookup.h"
21 #include "clang/Sema/Scope.h"
22 #include "clang/Sema/ScopeInfo.h"
23 #include "clang/Sema/SemaInternal.h"
24 #include "llvm/ADT/ArrayRef.h"
25 #include "llvm/ADT/StringSet.h"
26 #include "llvm/MC/MCParser/MCAsmParser.h"
27 using namespace clang;
30 /// Remove the upper-level LValueToRValue cast from an expression.
31 static void removeLValueToRValueCast(Expr *E) {
33 Expr *ExprUnderCast = nullptr;
34 SmallVector<Expr *, 8> ParentsToUpdate;
37 ParentsToUpdate.push_back(Parent);
38 if (auto *ParenE = dyn_cast<ParenExpr>(Parent)) {
39 Parent = ParenE->getSubExpr();
43 Expr *Child = nullptr;
44 CastExpr *ParentCast = dyn_cast<CastExpr>(Parent);
46 Child = ParentCast->getSubExpr();
50 if (auto *CastE = dyn_cast<CastExpr>(Child))
51 if (CastE->getCastKind() == CK_LValueToRValue) {
52 ExprUnderCast = CastE->getSubExpr();
53 // LValueToRValue cast inside GCCAsmStmt requires an explicit cast.
54 ParentCast->setSubExpr(ExprUnderCast);
60 // Update parent expressions to have same ValueType as the underlying.
61 assert(ExprUnderCast &&
62 "Should be reachable only if LValueToRValue cast was found!");
63 auto ValueKind = ExprUnderCast->getValueKind();
64 for (Expr *E : ParentsToUpdate)
65 E->setValueKind(ValueKind);
68 /// Emit a warning about usage of "noop"-like casts for lvalues (GNU extension)
69 /// and fix the argument with removing LValueToRValue cast from the expression.
70 static void emitAndFixInvalidAsmCastLValue(const Expr *LVal, Expr *BadArgument,
72 if (!S.getLangOpts().HeinousExtensions) {
73 S.Diag(LVal->getBeginLoc(), diag::err_invalid_asm_cast_lvalue)
74 << BadArgument->getSourceRange();
76 S.Diag(LVal->getBeginLoc(), diag::warn_invalid_asm_cast_lvalue)
77 << BadArgument->getSourceRange();
79 removeLValueToRValueCast(BadArgument);
82 /// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently
83 /// ignore "noop" casts in places where an lvalue is required by an inline asm.
84 /// We emulate this behavior when -fheinous-gnu-extensions is specified, but
85 /// provide a strong guidance to not use it.
87 /// This method checks to see if the argument is an acceptable l-value and
88 /// returns false if it is a case we can handle.
89 static bool CheckAsmLValue(Expr *E, Sema &S) {
90 // Type dependent expressions will be checked during instantiation.
91 if (E->isTypeDependent())
95 return false; // Cool, this is an lvalue.
97 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we
98 // are supposed to allow.
99 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context);
100 if (E != E2 && E2->isLValue()) {
101 emitAndFixInvalidAsmCastLValue(E2, E, S);
102 // Accept, even if we emitted an error diagnostic.
106 // None of the above, just randomly invalid non-lvalue.
110 /// isOperandMentioned - Return true if the specified operand # is mentioned
111 /// anywhere in the decomposed asm string.
113 isOperandMentioned(unsigned OpNo,
114 ArrayRef<GCCAsmStmt::AsmStringPiece> AsmStrPieces) {
115 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) {
116 const GCCAsmStmt::AsmStringPiece &Piece = AsmStrPieces[p];
117 if (!Piece.isOperand())
120 // If this is a reference to the input and if the input was the smaller
121 // one, then we have to reject this asm.
122 if (Piece.getOperandNo() == OpNo)
128 static bool CheckNakedParmReference(Expr *E, Sema &S) {
129 FunctionDecl *Func = dyn_cast<FunctionDecl>(S.CurContext);
132 if (!Func->hasAttr<NakedAttr>())
135 SmallVector<Expr*, 4> WorkList;
136 WorkList.push_back(E);
137 while (WorkList.size()) {
138 Expr *E = WorkList.pop_back_val();
139 if (isa<CXXThisExpr>(E)) {
140 S.Diag(E->getBeginLoc(), diag::err_asm_naked_this_ref);
141 S.Diag(Func->getAttr<NakedAttr>()->getLocation(), diag::note_attribute);
144 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
145 if (isa<ParmVarDecl>(DRE->getDecl())) {
146 S.Diag(DRE->getBeginLoc(), diag::err_asm_naked_parm_ref);
147 S.Diag(Func->getAttr<NakedAttr>()->getLocation(), diag::note_attribute);
151 for (Stmt *Child : E->children()) {
152 if (Expr *E = dyn_cast_or_null<Expr>(Child))
153 WorkList.push_back(E);
159 /// Returns true if given expression is not compatible with inline
160 /// assembly's memory constraint; false otherwise.
161 static bool checkExprMemoryConstraintCompat(Sema &S, Expr *E,
162 TargetInfo::ConstraintInfo &Info,
163 bool is_input_expr) {
169 } EType = ExprSafeType;
171 // Bitfields, vector elements and global register variables are not
173 if (E->refersToBitField())
174 EType = ExprBitfield;
175 else if (E->refersToVectorElement())
176 EType = ExprVectorElt;
177 else if (E->refersToGlobalRegisterVar())
178 EType = ExprGlobalRegVar;
180 if (EType != ExprSafeType) {
181 S.Diag(E->getBeginLoc(), diag::err_asm_non_addr_value_in_memory_constraint)
182 << EType << is_input_expr << Info.getConstraintStr()
183 << E->getSourceRange();
190 // Extracting the register name from the Expression value,
191 // if there is no register name to extract, returns ""
192 static StringRef extractRegisterName(const Expr *Expression,
193 const TargetInfo &Target) {
194 Expression = Expression->IgnoreImpCasts();
195 if (const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(Expression)) {
196 // Handle cases where the expression is a variable
197 const VarDecl *Variable = dyn_cast<VarDecl>(AsmDeclRef->getDecl());
198 if (Variable && Variable->getStorageClass() == SC_Register) {
199 if (AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>())
200 if (Target.isValidGCCRegisterName(Attr->getLabel()))
201 return Target.getNormalizedGCCRegisterName(Attr->getLabel(), true);
207 // Checks if there is a conflict between the input and output lists with the
208 // clobbers list. If there's a conflict, returns the location of the
209 // conflicted clobber, else returns nullptr
210 static SourceLocation
211 getClobberConflictLocation(MultiExprArg Exprs, StringLiteral **Constraints,
212 StringLiteral **Clobbers, int NumClobbers,
213 const TargetInfo &Target, ASTContext &Cont) {
214 llvm::StringSet<> InOutVars;
215 // Collect all the input and output registers from the extended asm
216 // statement in order to check for conflicts with the clobber list
217 for (unsigned int i = 0; i < Exprs.size(); ++i) {
218 StringRef Constraint = Constraints[i]->getString();
219 StringRef InOutReg = Target.getConstraintRegister(
220 Constraint, extractRegisterName(Exprs[i], Target));
222 InOutVars.insert(InOutReg);
224 // Check for each item in the clobber list if it conflicts with the input
226 for (int i = 0; i < NumClobbers; ++i) {
227 StringRef Clobber = Clobbers[i]->getString();
228 // We only check registers, therefore we don't check cc and memory
230 if (Clobber == "cc" || Clobber == "memory")
232 Clobber = Target.getNormalizedGCCRegisterName(Clobber, true);
233 // Go over the output's registers we collected
234 if (InOutVars.count(Clobber))
235 return Clobbers[i]->getBeginLoc();
237 return SourceLocation();
240 StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
241 bool IsVolatile, unsigned NumOutputs,
242 unsigned NumInputs, IdentifierInfo **Names,
243 MultiExprArg constraints, MultiExprArg Exprs,
244 Expr *asmString, MultiExprArg clobbers,
245 SourceLocation RParenLoc) {
246 unsigned NumClobbers = clobbers.size();
247 StringLiteral **Constraints =
248 reinterpret_cast<StringLiteral**>(constraints.data());
249 StringLiteral *AsmString = cast<StringLiteral>(asmString);
250 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.data());
252 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
254 // The parser verifies that there is a string literal here.
255 assert(AsmString->isAscii());
257 // If we're compiling CUDA file and function attributes indicate that it's not
258 // for this compilation side, skip all the checks.
259 if (!DeclAttrsMatchCUDAMode(getLangOpts(), getCurFunctionDecl())) {
260 GCCAsmStmt *NS = new (Context) GCCAsmStmt(
261 Context, AsmLoc, IsSimple, IsVolatile, NumOutputs, NumInputs, Names,
262 Constraints, Exprs.data(), AsmString, NumClobbers, Clobbers, RParenLoc);
266 for (unsigned i = 0; i != NumOutputs; i++) {
267 StringLiteral *Literal = Constraints[i];
268 assert(Literal->isAscii());
270 StringRef OutputName;
272 OutputName = Names[i]->getName();
274 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName);
275 if (!Context.getTargetInfo().validateOutputConstraint(Info))
277 Diag(Literal->getBeginLoc(), diag::err_asm_invalid_output_constraint)
278 << Info.getConstraintStr());
280 ExprResult ER = CheckPlaceholderExpr(Exprs[i]);
285 // Check that the output exprs are valid lvalues.
286 Expr *OutputExpr = Exprs[i];
288 // Referring to parameters is not allowed in naked functions.
289 if (CheckNakedParmReference(OutputExpr, *this))
292 // Check that the output expression is compatible with memory constraint.
293 if (Info.allowsMemory() &&
294 checkExprMemoryConstraintCompat(*this, OutputExpr, Info, false))
297 OutputConstraintInfos.push_back(Info);
299 // If this is dependent, just continue.
300 if (OutputExpr->isTypeDependent())
303 Expr::isModifiableLvalueResult IsLV =
304 OutputExpr->isModifiableLvalue(Context, /*Loc=*/nullptr);
306 case Expr::MLV_Valid:
307 // Cool, this is an lvalue.
309 case Expr::MLV_ArrayType:
312 case Expr::MLV_LValueCast: {
313 const Expr *LVal = OutputExpr->IgnoreParenNoopCasts(Context);
314 emitAndFixInvalidAsmCastLValue(LVal, OutputExpr, *this);
315 // Accept, even if we emitted an error diagnostic.
318 case Expr::MLV_IncompleteType:
319 case Expr::MLV_IncompleteVoidType:
320 if (RequireCompleteType(OutputExpr->getBeginLoc(), Exprs[i]->getType(),
321 diag::err_dereference_incomplete_type))
325 return StmtError(Diag(OutputExpr->getBeginLoc(),
326 diag::err_asm_invalid_lvalue_in_output)
327 << OutputExpr->getSourceRange());
330 unsigned Size = Context.getTypeSize(OutputExpr->getType());
331 if (!Context.getTargetInfo().validateOutputSize(Literal->getString(),
334 Diag(OutputExpr->getBeginLoc(), diag::err_asm_invalid_output_size)
335 << Info.getConstraintStr());
338 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
340 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
341 StringLiteral *Literal = Constraints[i];
342 assert(Literal->isAscii());
346 InputName = Names[i]->getName();
348 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName);
349 if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos,
352 Diag(Literal->getBeginLoc(), diag::err_asm_invalid_input_constraint)
353 << Info.getConstraintStr());
356 ExprResult ER = CheckPlaceholderExpr(Exprs[i]);
361 Expr *InputExpr = Exprs[i];
363 // Referring to parameters is not allowed in naked functions.
364 if (CheckNakedParmReference(InputExpr, *this))
367 // Check that the input expression is compatible with memory constraint.
368 if (Info.allowsMemory() &&
369 checkExprMemoryConstraintCompat(*this, InputExpr, Info, true))
372 // Only allow void types for memory constraints.
373 if (Info.allowsMemory() && !Info.allowsRegister()) {
374 if (CheckAsmLValue(InputExpr, *this))
375 return StmtError(Diag(InputExpr->getBeginLoc(),
376 diag::err_asm_invalid_lvalue_in_input)
377 << Info.getConstraintStr()
378 << InputExpr->getSourceRange());
379 } else if (Info.requiresImmediateConstant() && !Info.allowsRegister()) {
380 if (!InputExpr->isValueDependent()) {
381 Expr::EvalResult EVResult;
382 if (!InputExpr->EvaluateAsRValue(EVResult, Context, true))
384 Diag(InputExpr->getBeginLoc(), diag::err_asm_immediate_expected)
385 << Info.getConstraintStr() << InputExpr->getSourceRange());
386 llvm::APSInt Result = EVResult.Val.getInt();
387 if (!Info.isValidAsmImmediate(Result))
388 return StmtError(Diag(InputExpr->getBeginLoc(),
389 diag::err_invalid_asm_value_for_constraint)
390 << Result.toString(10) << Info.getConstraintStr()
391 << InputExpr->getSourceRange());
395 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]);
396 if (Result.isInvalid())
399 Exprs[i] = Result.get();
402 if (Info.allowsRegister()) {
403 if (InputExpr->getType()->isVoidType()) {
405 Diag(InputExpr->getBeginLoc(), diag::err_asm_invalid_type_in_input)
406 << InputExpr->getType() << Info.getConstraintStr()
407 << InputExpr->getSourceRange());
411 InputConstraintInfos.push_back(Info);
413 const Type *Ty = Exprs[i]->getType().getTypePtr();
414 if (Ty->isDependentType())
417 if (!Ty->isVoidType() || !Info.allowsMemory())
418 if (RequireCompleteType(InputExpr->getBeginLoc(), Exprs[i]->getType(),
419 diag::err_dereference_incomplete_type))
422 unsigned Size = Context.getTypeSize(Ty);
423 if (!Context.getTargetInfo().validateInputSize(Literal->getString(),
426 Diag(InputExpr->getBeginLoc(), diag::err_asm_invalid_input_size)
427 << Info.getConstraintStr());
430 // Check that the clobbers are valid.
431 for (unsigned i = 0; i != NumClobbers; i++) {
432 StringLiteral *Literal = Clobbers[i];
433 assert(Literal->isAscii());
435 StringRef Clobber = Literal->getString();
437 if (!Context.getTargetInfo().isValidClobber(Clobber))
439 Diag(Literal->getBeginLoc(), diag::err_asm_unknown_register_name)
444 new (Context) GCCAsmStmt(Context, AsmLoc, IsSimple, IsVolatile, NumOutputs,
445 NumInputs, Names, Constraints, Exprs.data(),
446 AsmString, NumClobbers, Clobbers, RParenLoc);
447 // Validate the asm string, ensuring it makes sense given the operands we
449 SmallVector<GCCAsmStmt::AsmStringPiece, 8> Pieces;
451 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) {
452 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID)
453 << AsmString->getSourceRange();
457 // Validate constraints and modifiers.
458 for (unsigned i = 0, e = Pieces.size(); i != e; ++i) {
459 GCCAsmStmt::AsmStringPiece &Piece = Pieces[i];
460 if (!Piece.isOperand()) continue;
462 // Look for the correct constraint index.
463 unsigned ConstraintIdx = Piece.getOperandNo();
464 unsigned NumOperands = NS->getNumOutputs() + NS->getNumInputs();
466 // Look for the (ConstraintIdx - NumOperands + 1)th constraint with
468 if (ConstraintIdx >= NumOperands) {
469 unsigned I = 0, E = NS->getNumOutputs();
471 for (unsigned Cnt = ConstraintIdx - NumOperands; I != E; ++I)
472 if (OutputConstraintInfos[I].isReadWrite() && Cnt-- == 0) {
477 assert(I != E && "Invalid operand number should have been caught in "
478 " AnalyzeAsmString");
481 // Now that we have the right indexes go ahead and check.
482 StringLiteral *Literal = Constraints[ConstraintIdx];
483 const Type *Ty = Exprs[ConstraintIdx]->getType().getTypePtr();
484 if (Ty->isDependentType() || Ty->isIncompleteType())
487 unsigned Size = Context.getTypeSize(Ty);
488 std::string SuggestedModifier;
489 if (!Context.getTargetInfo().validateConstraintModifier(
490 Literal->getString(), Piece.getModifier(), Size,
491 SuggestedModifier)) {
492 Diag(Exprs[ConstraintIdx]->getBeginLoc(),
493 diag::warn_asm_mismatched_size_modifier);
495 if (!SuggestedModifier.empty()) {
496 auto B = Diag(Piece.getRange().getBegin(),
497 diag::note_asm_missing_constraint_modifier)
498 << SuggestedModifier;
499 SuggestedModifier = "%" + SuggestedModifier + Piece.getString();
500 B.AddFixItHint(FixItHint::CreateReplacement(Piece.getRange(),
506 // Validate tied input operands for type mismatches.
507 unsigned NumAlternatives = ~0U;
508 for (unsigned i = 0, e = OutputConstraintInfos.size(); i != e; ++i) {
509 TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
510 StringRef ConstraintStr = Info.getConstraintStr();
511 unsigned AltCount = ConstraintStr.count(',') + 1;
512 if (NumAlternatives == ~0U)
513 NumAlternatives = AltCount;
514 else if (NumAlternatives != AltCount)
515 return StmtError(Diag(NS->getOutputExpr(i)->getBeginLoc(),
516 diag::err_asm_unexpected_constraint_alternatives)
517 << NumAlternatives << AltCount);
519 SmallVector<size_t, 4> InputMatchedToOutput(OutputConstraintInfos.size(),
521 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
522 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
523 StringRef ConstraintStr = Info.getConstraintStr();
524 unsigned AltCount = ConstraintStr.count(',') + 1;
525 if (NumAlternatives == ~0U)
526 NumAlternatives = AltCount;
527 else if (NumAlternatives != AltCount)
528 return StmtError(Diag(NS->getInputExpr(i)->getBeginLoc(),
529 diag::err_asm_unexpected_constraint_alternatives)
530 << NumAlternatives << AltCount);
532 // If this is a tied constraint, verify that the output and input have
533 // either exactly the same type, or that they are int/ptr operands with the
534 // same size (int/long, int*/long, are ok etc).
535 if (!Info.hasTiedOperand()) continue;
537 unsigned TiedTo = Info.getTiedOperand();
538 unsigned InputOpNo = i+NumOutputs;
539 Expr *OutputExpr = Exprs[TiedTo];
540 Expr *InputExpr = Exprs[InputOpNo];
542 // Make sure no more than one input constraint matches each output.
543 assert(TiedTo < InputMatchedToOutput.size() && "TiedTo value out of range");
544 if (InputMatchedToOutput[TiedTo] != ~0U) {
545 Diag(NS->getInputExpr(i)->getBeginLoc(),
546 diag::err_asm_input_duplicate_match)
548 Diag(NS->getInputExpr(InputMatchedToOutput[TiedTo])->getBeginLoc(),
549 diag::note_asm_input_duplicate_first)
553 InputMatchedToOutput[TiedTo] = i;
555 if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent())
558 QualType InTy = InputExpr->getType();
559 QualType OutTy = OutputExpr->getType();
560 if (Context.hasSameType(InTy, OutTy))
561 continue; // All types can be tied to themselves.
563 // Decide if the input and output are in the same domain (integer/ptr or
566 AD_Int, AD_FP, AD_Other
567 } InputDomain, OutputDomain;
569 if (InTy->isIntegerType() || InTy->isPointerType())
570 InputDomain = AD_Int;
571 else if (InTy->isRealFloatingType())
574 InputDomain = AD_Other;
576 if (OutTy->isIntegerType() || OutTy->isPointerType())
577 OutputDomain = AD_Int;
578 else if (OutTy->isRealFloatingType())
579 OutputDomain = AD_FP;
581 OutputDomain = AD_Other;
583 // They are ok if they are the same size and in the same domain. This
584 // allows tying things like:
586 // void* to int if they are the same size.
587 // double to long double if they are the same size.
589 uint64_t OutSize = Context.getTypeSize(OutTy);
590 uint64_t InSize = Context.getTypeSize(InTy);
591 if (OutSize == InSize && InputDomain == OutputDomain &&
592 InputDomain != AD_Other)
595 // If the smaller input/output operand is not mentioned in the asm string,
596 // then we can promote the smaller one to a larger input and the asm string
598 bool SmallerValueMentioned = false;
600 // If this is a reference to the input and if the input was the smaller
601 // one, then we have to reject this asm.
602 if (isOperandMentioned(InputOpNo, Pieces)) {
603 // This is a use in the asm string of the smaller operand. Since we
604 // codegen this by promoting to a wider value, the asm will get printed
606 SmallerValueMentioned |= InSize < OutSize;
608 if (isOperandMentioned(TiedTo, Pieces)) {
609 // If this is a reference to the output, and if the output is the larger
610 // value, then it's ok because we'll promote the input to the larger type.
611 SmallerValueMentioned |= OutSize < InSize;
614 // If the smaller value wasn't mentioned in the asm string, and if the
615 // output was a register, just extend the shorter one to the size of the
617 if (!SmallerValueMentioned && InputDomain != AD_Other &&
618 OutputConstraintInfos[TiedTo].allowsRegister())
621 // Either both of the operands were mentioned or the smaller one was
622 // mentioned. One more special case that we'll allow: if the tied input is
623 // integer, unmentioned, and is a constant, then we'll allow truncating it
624 // down to the size of the destination.
625 if (InputDomain == AD_Int && OutputDomain == AD_Int &&
626 !isOperandMentioned(InputOpNo, Pieces) &&
627 InputExpr->isEvaluatable(Context)) {
629 (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast);
630 InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).get();
631 Exprs[InputOpNo] = InputExpr;
632 NS->setInputExpr(i, InputExpr);
636 Diag(InputExpr->getBeginLoc(), diag::err_asm_tying_incompatible_types)
637 << InTy << OutTy << OutputExpr->getSourceRange()
638 << InputExpr->getSourceRange();
642 // Check for conflicts between clobber list and input or output lists
643 SourceLocation ConstraintLoc =
644 getClobberConflictLocation(Exprs, Constraints, Clobbers, NumClobbers,
645 Context.getTargetInfo(), Context);
646 if (ConstraintLoc.isValid())
647 return Diag(ConstraintLoc, diag::error_inoutput_conflict_with_clobber);
652 void Sema::FillInlineAsmIdentifierInfo(Expr *Res,
653 llvm::InlineAsmIdentifierInfo &Info) {
654 QualType T = Res->getType();
655 Expr::EvalResult Eval;
656 if (T->isFunctionType() || T->isDependentType())
657 return Info.setLabel(Res);
658 if (Res->isRValue()) {
659 if (isa<clang::EnumType>(T) && Res->EvaluateAsRValue(Eval, Context))
660 return Info.setEnum(Eval.Val.getInt().getSExtValue());
661 return Info.setLabel(Res);
663 unsigned Size = Context.getTypeSizeInChars(T).getQuantity();
664 unsigned Type = Size;
665 if (const auto *ATy = Context.getAsArrayType(T))
666 Type = Context.getTypeSizeInChars(ATy->getElementType()).getQuantity();
667 bool IsGlobalLV = false;
668 if (Res->EvaluateAsLValue(Eval, Context))
669 IsGlobalLV = Eval.isGlobalLValue();
670 Info.setVar(Res, IsGlobalLV, Size, Type);
673 ExprResult Sema::LookupInlineAsmIdentifier(CXXScopeSpec &SS,
674 SourceLocation TemplateKWLoc,
676 bool IsUnevaluatedContext) {
678 if (IsUnevaluatedContext)
679 PushExpressionEvaluationContext(
680 ExpressionEvaluationContext::UnevaluatedAbstract,
681 ReuseLambdaContextDecl);
683 ExprResult Result = ActOnIdExpression(getCurScope(), SS, TemplateKWLoc, Id,
684 /*trailing lparen*/ false,
685 /*is & operand*/ false,
686 /*CorrectionCandidateCallback=*/nullptr,
687 /*IsInlineAsmIdentifier=*/ true);
689 if (IsUnevaluatedContext)
690 PopExpressionEvaluationContext();
692 if (!Result.isUsable()) return Result;
694 Result = CheckPlaceholderExpr(Result.get());
695 if (!Result.isUsable()) return Result;
697 // Referring to parameters is not allowed in naked functions.
698 if (CheckNakedParmReference(Result.get(), *this))
701 QualType T = Result.get()->getType();
703 if (T->isDependentType()) {
707 // Any sort of function type is fine.
708 if (T->isFunctionType()) {
712 // Otherwise, it needs to be a complete type.
713 if (RequireCompleteExprType(Result.get(), diag::err_asm_incomplete_type)) {
720 bool Sema::LookupInlineAsmField(StringRef Base, StringRef Member,
721 unsigned &Offset, SourceLocation AsmLoc) {
723 SmallVector<StringRef, 2> Members;
724 Member.split(Members, ".");
726 NamedDecl *FoundDecl = nullptr;
728 // MS InlineAsm uses 'this' as a base
729 if (getLangOpts().CPlusPlus && Base.equals("this")) {
730 if (const Type *PT = getCurrentThisType().getTypePtrOrNull())
731 FoundDecl = PT->getPointeeType()->getAsTagDecl();
733 LookupResult BaseResult(*this, &Context.Idents.get(Base), SourceLocation(),
735 if (LookupName(BaseResult, getCurScope()) && BaseResult.isSingleResult())
736 FoundDecl = BaseResult.getFoundDecl();
742 for (StringRef NextMember : Members) {
743 const RecordType *RT = nullptr;
744 if (VarDecl *VD = dyn_cast<VarDecl>(FoundDecl))
745 RT = VD->getType()->getAs<RecordType>();
746 else if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(FoundDecl)) {
747 MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
748 // MS InlineAsm often uses struct pointer aliases as a base
749 QualType QT = TD->getUnderlyingType();
750 if (const auto *PT = QT->getAs<PointerType>())
751 QT = PT->getPointeeType();
752 RT = QT->getAs<RecordType>();
753 } else if (TypeDecl *TD = dyn_cast<TypeDecl>(FoundDecl))
754 RT = TD->getTypeForDecl()->getAs<RecordType>();
755 else if (FieldDecl *TD = dyn_cast<FieldDecl>(FoundDecl))
756 RT = TD->getType()->getAs<RecordType>();
760 if (RequireCompleteType(AsmLoc, QualType(RT, 0),
761 diag::err_asm_incomplete_type))
764 LookupResult FieldResult(*this, &Context.Idents.get(NextMember),
765 SourceLocation(), LookupMemberName);
767 if (!LookupQualifiedName(FieldResult, RT->getDecl()))
770 if (!FieldResult.isSingleResult())
772 FoundDecl = FieldResult.getFoundDecl();
774 // FIXME: Handle IndirectFieldDecl?
775 FieldDecl *FD = dyn_cast<FieldDecl>(FoundDecl);
779 const ASTRecordLayout &RL = Context.getASTRecordLayout(RT->getDecl());
780 unsigned i = FD->getFieldIndex();
781 CharUnits Result = Context.toCharUnitsFromBits(RL.getFieldOffset(i));
782 Offset += (unsigned)Result.getQuantity();
789 Sema::LookupInlineAsmVarDeclField(Expr *E, StringRef Member,
790 SourceLocation AsmLoc) {
792 QualType T = E->getType();
793 if (T->isDependentType()) {
794 DeclarationNameInfo NameInfo;
795 NameInfo.setLoc(AsmLoc);
796 NameInfo.setName(&Context.Idents.get(Member));
797 return CXXDependentScopeMemberExpr::Create(
798 Context, E, T, /*IsArrow=*/false, AsmLoc, NestedNameSpecifierLoc(),
800 /*FirstQualifierInScope=*/nullptr, NameInfo, /*TemplateArgs=*/nullptr);
803 const RecordType *RT = T->getAs<RecordType>();
804 // FIXME: Diagnose this as field access into a scalar type.
808 LookupResult FieldResult(*this, &Context.Idents.get(Member), AsmLoc,
811 if (!LookupQualifiedName(FieldResult, RT->getDecl()))
814 // Only normal and indirect field results will work.
815 ValueDecl *FD = dyn_cast<FieldDecl>(FieldResult.getFoundDecl());
817 FD = dyn_cast<IndirectFieldDecl>(FieldResult.getFoundDecl());
821 // Make an Expr to thread through OpDecl.
822 ExprResult Result = BuildMemberReferenceExpr(
823 E, E->getType(), AsmLoc, /*IsArrow=*/false, CXXScopeSpec(),
824 SourceLocation(), nullptr, FieldResult, nullptr, nullptr);
829 StmtResult Sema::ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
830 ArrayRef<Token> AsmToks,
832 unsigned NumOutputs, unsigned NumInputs,
833 ArrayRef<StringRef> Constraints,
834 ArrayRef<StringRef> Clobbers,
835 ArrayRef<Expr*> Exprs,
836 SourceLocation EndLoc) {
837 bool IsSimple = (NumOutputs != 0 || NumInputs != 0);
838 setFunctionHasBranchProtectedScope();
840 new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, IsSimple,
841 /*IsVolatile*/ true, AsmToks, NumOutputs, NumInputs,
842 Constraints, Exprs, AsmString,
847 LabelDecl *Sema::GetOrCreateMSAsmLabel(StringRef ExternalLabelName,
848 SourceLocation Location,
850 LabelDecl* Label = LookupOrCreateLabel(PP.getIdentifierInfo(ExternalLabelName),
853 if (Label->isMSAsmLabel()) {
854 // If we have previously created this label implicitly, mark it as used.
855 Label->markUsed(Context);
857 // Otherwise, insert it, but only resolve it if we have seen the label itself.
858 std::string InternalName;
859 llvm::raw_string_ostream OS(InternalName);
860 // Create an internal name for the label. The name should not be a valid
861 // mangled name, and should be unique. We use a dot to make the name an
862 // invalid mangled name. We use LLVM's inline asm ${:uid} escape so that a
863 // unique label is generated each time this blob is emitted, even after
865 OS << "__MSASMLABEL_.${:uid}__";
866 for (char C : ExternalLabelName) {
868 // We escape '$' in asm strings by replacing it with "$$"
872 Label->setMSAsmLabel(OS.str());
875 // The label might have been created implicitly from a previously encountered
876 // goto statement. So, for both newly created and looked up labels, we mark
878 Label->setMSAsmLabelResolved();
880 // Adjust their location for being able to generate accurate diagnostics.
881 Label->setLocation(Location);