diff options
Diffstat (limited to 'clang/lib/Sema/SemaStmtAsm.cpp')
| -rw-r--r-- | clang/lib/Sema/SemaStmtAsm.cpp | 930 |
1 files changed, 930 insertions, 0 deletions
diff --git a/clang/lib/Sema/SemaStmtAsm.cpp b/clang/lib/Sema/SemaStmtAsm.cpp new file mode 100644 index 0000000000000..9b051e02d1275 --- /dev/null +++ b/clang/lib/Sema/SemaStmtAsm.cpp @@ -0,0 +1,930 @@ +//===--- SemaStmtAsm.cpp - Semantic Analysis for Asm Statements -----------===// +// +// 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 semantic analysis for inline asm statements. +// +//===----------------------------------------------------------------------===// + +#include "clang/AST/ExprCXX.h" +#include "clang/AST/RecordLayout.h" +#include "clang/AST/TypeLoc.h" +#include "clang/Basic/TargetInfo.h" +#include "clang/Lex/Preprocessor.h" +#include "clang/Sema/Initialization.h" +#include "clang/Sema/Lookup.h" +#include "clang/Sema/Scope.h" +#include "clang/Sema/ScopeInfo.h" +#include "clang/Sema/SemaInternal.h" +#include "llvm/ADT/ArrayRef.h" +#include "llvm/ADT/StringSet.h" +#include "llvm/MC/MCParser/MCAsmParser.h" +using namespace clang; +using namespace sema; + +/// Remove the upper-level LValueToRValue cast from an expression. +static void removeLValueToRValueCast(Expr *E) { + Expr *Parent = E; + Expr *ExprUnderCast = nullptr; + SmallVector<Expr *, 8> ParentsToUpdate; + + while (true) { + ParentsToUpdate.push_back(Parent); + if (auto *ParenE = dyn_cast<ParenExpr>(Parent)) { + Parent = ParenE->getSubExpr(); + continue; + } + + Expr *Child = nullptr; + CastExpr *ParentCast = dyn_cast<CastExpr>(Parent); + if (ParentCast) + Child = ParentCast->getSubExpr(); + else + return; + + if (auto *CastE = dyn_cast<CastExpr>(Child)) + if (CastE->getCastKind() == CK_LValueToRValue) { + ExprUnderCast = CastE->getSubExpr(); + // LValueToRValue cast inside GCCAsmStmt requires an explicit cast. + ParentCast->setSubExpr(ExprUnderCast); + break; + } + Parent = Child; + } + + // Update parent expressions to have same ValueType as the underlying. + assert(ExprUnderCast && + "Should be reachable only if LValueToRValue cast was found!"); + auto ValueKind = ExprUnderCast->getValueKind(); + for (Expr *E : ParentsToUpdate) + E->setValueKind(ValueKind); +} + +/// Emit a warning about usage of "noop"-like casts for lvalues (GNU extension) +/// and fix the argument with removing LValueToRValue cast from the expression. +static void emitAndFixInvalidAsmCastLValue(const Expr *LVal, Expr *BadArgument, + Sema &S) { + if (!S.getLangOpts().HeinousExtensions) { + S.Diag(LVal->getBeginLoc(), diag::err_invalid_asm_cast_lvalue) + << BadArgument->getSourceRange(); + } else { + S.Diag(LVal->getBeginLoc(), diag::warn_invalid_asm_cast_lvalue) + << BadArgument->getSourceRange(); + } + removeLValueToRValueCast(BadArgument); +} + +/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently +/// ignore "noop" casts in places where an lvalue is required by an inline asm. +/// We emulate this behavior when -fheinous-gnu-extensions is specified, but +/// provide a strong guidance to not use it. +/// +/// This method checks to see if the argument is an acceptable l-value and +/// returns false if it is a case we can handle. +static bool CheckAsmLValue(Expr *E, Sema &S) { + // Type dependent expressions will be checked during instantiation. + if (E->isTypeDependent()) + return false; + + if (E->isLValue()) + return false; // Cool, this is an lvalue. + + // Okay, this is not an lvalue, but perhaps it is the result of a cast that we + // are supposed to allow. + const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); + if (E != E2 && E2->isLValue()) { + emitAndFixInvalidAsmCastLValue(E2, E, S); + // Accept, even if we emitted an error diagnostic. + return false; + } + + // None of the above, just randomly invalid non-lvalue. + return true; +} + +/// isOperandMentioned - Return true if the specified operand # is mentioned +/// anywhere in the decomposed asm string. +static bool +isOperandMentioned(unsigned OpNo, + ArrayRef<GCCAsmStmt::AsmStringPiece> AsmStrPieces) { + for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { + const GCCAsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; + if (!Piece.isOperand()) + continue; + + // If this is a reference to the input and if the input was the smaller + // one, then we have to reject this asm. + if (Piece.getOperandNo() == OpNo) + return true; + } + return false; +} + +static bool CheckNakedParmReference(Expr *E, Sema &S) { + FunctionDecl *Func = dyn_cast<FunctionDecl>(S.CurContext); + if (!Func) + return false; + if (!Func->hasAttr<NakedAttr>()) + return false; + + SmallVector<Expr*, 4> WorkList; + WorkList.push_back(E); + while (WorkList.size()) { + Expr *E = WorkList.pop_back_val(); + if (isa<CXXThisExpr>(E)) { + S.Diag(E->getBeginLoc(), diag::err_asm_naked_this_ref); + S.Diag(Func->getAttr<NakedAttr>()->getLocation(), diag::note_attribute); + return true; + } + if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { + if (isa<ParmVarDecl>(DRE->getDecl())) { + S.Diag(DRE->getBeginLoc(), diag::err_asm_naked_parm_ref); + S.Diag(Func->getAttr<NakedAttr>()->getLocation(), diag::note_attribute); + return true; + } + } + for (Stmt *Child : E->children()) { + if (Expr *E = dyn_cast_or_null<Expr>(Child)) + WorkList.push_back(E); + } + } + return false; +} + +/// Returns true if given expression is not compatible with inline +/// assembly's memory constraint; false otherwise. +static bool checkExprMemoryConstraintCompat(Sema &S, Expr *E, + TargetInfo::ConstraintInfo &Info, + bool is_input_expr) { + enum { + ExprBitfield = 0, + ExprVectorElt, + ExprGlobalRegVar, + ExprSafeType + } EType = ExprSafeType; + + // Bitfields, vector elements and global register variables are not + // compatible. + if (E->refersToBitField()) + EType = ExprBitfield; + else if (E->refersToVectorElement()) + EType = ExprVectorElt; + else if (E->refersToGlobalRegisterVar()) + EType = ExprGlobalRegVar; + + if (EType != ExprSafeType) { + S.Diag(E->getBeginLoc(), diag::err_asm_non_addr_value_in_memory_constraint) + << EType << is_input_expr << Info.getConstraintStr() + << E->getSourceRange(); + return true; + } + + return false; +} + +// Extracting the register name from the Expression value, +// if there is no register name to extract, returns "" +static StringRef extractRegisterName(const Expr *Expression, + const TargetInfo &Target) { + Expression = Expression->IgnoreImpCasts(); + if (const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(Expression)) { + // Handle cases where the expression is a variable + const VarDecl *Variable = dyn_cast<VarDecl>(AsmDeclRef->getDecl()); + if (Variable && Variable->getStorageClass() == SC_Register) { + if (AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>()) + if (Target.isValidGCCRegisterName(Attr->getLabel())) + return Target.getNormalizedGCCRegisterName(Attr->getLabel(), true); + } + } + return ""; +} + +// Checks if there is a conflict between the input and output lists with the +// clobbers list. If there's a conflict, returns the location of the +// conflicted clobber, else returns nullptr +static SourceLocation +getClobberConflictLocation(MultiExprArg Exprs, StringLiteral **Constraints, + StringLiteral **Clobbers, int NumClobbers, + unsigned NumLabels, + const TargetInfo &Target, ASTContext &Cont) { + llvm::StringSet<> InOutVars; + // Collect all the input and output registers from the extended asm + // statement in order to check for conflicts with the clobber list + for (unsigned int i = 0; i < Exprs.size() - NumLabels; ++i) { + StringRef Constraint = Constraints[i]->getString(); + StringRef InOutReg = Target.getConstraintRegister( + Constraint, extractRegisterName(Exprs[i], Target)); + if (InOutReg != "") + InOutVars.insert(InOutReg); + } + // Check for each item in the clobber list if it conflicts with the input + // or output + for (int i = 0; i < NumClobbers; ++i) { + StringRef Clobber = Clobbers[i]->getString(); + // We only check registers, therefore we don't check cc and memory + // clobbers + if (Clobber == "cc" || Clobber == "memory") + continue; + Clobber = Target.getNormalizedGCCRegisterName(Clobber, true); + // Go over the output's registers we collected + if (InOutVars.count(Clobber)) + return Clobbers[i]->getBeginLoc(); + } + return SourceLocation(); +} + +StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple, + bool IsVolatile, unsigned NumOutputs, + unsigned NumInputs, IdentifierInfo **Names, + MultiExprArg constraints, MultiExprArg Exprs, + Expr *asmString, MultiExprArg clobbers, + unsigned NumLabels, + SourceLocation RParenLoc) { + unsigned NumClobbers = clobbers.size(); + StringLiteral **Constraints = + reinterpret_cast<StringLiteral**>(constraints.data()); + StringLiteral *AsmString = cast<StringLiteral>(asmString); + StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.data()); + + SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; + + // The parser verifies that there is a string literal here. + assert(AsmString->isAscii()); + + for (unsigned i = 0; i != NumOutputs; i++) { + StringLiteral *Literal = Constraints[i]; + assert(Literal->isAscii()); + + StringRef OutputName; + if (Names[i]) + OutputName = Names[i]->getName(); + + TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); + if (!Context.getTargetInfo().validateOutputConstraint(Info)) { + targetDiag(Literal->getBeginLoc(), + diag::err_asm_invalid_output_constraint) + << Info.getConstraintStr(); + return new (Context) + GCCAsmStmt(Context, AsmLoc, IsSimple, IsVolatile, NumOutputs, + NumInputs, Names, Constraints, Exprs.data(), AsmString, + NumClobbers, Clobbers, NumLabels, RParenLoc); + } + + ExprResult ER = CheckPlaceholderExpr(Exprs[i]); + if (ER.isInvalid()) + return StmtError(); + Exprs[i] = ER.get(); + + // Check that the output exprs are valid lvalues. + Expr *OutputExpr = Exprs[i]; + + // Referring to parameters is not allowed in naked functions. + if (CheckNakedParmReference(OutputExpr, *this)) + return StmtError(); + + // Check that the output expression is compatible with memory constraint. + if (Info.allowsMemory() && + checkExprMemoryConstraintCompat(*this, OutputExpr, Info, false)) + return StmtError(); + + OutputConstraintInfos.push_back(Info); + + // If this is dependent, just continue. + if (OutputExpr->isTypeDependent()) + continue; + + Expr::isModifiableLvalueResult IsLV = + OutputExpr->isModifiableLvalue(Context, /*Loc=*/nullptr); + switch (IsLV) { + case Expr::MLV_Valid: + // Cool, this is an lvalue. + break; + case Expr::MLV_ArrayType: + // This is OK too. + break; + case Expr::MLV_LValueCast: { + const Expr *LVal = OutputExpr->IgnoreParenNoopCasts(Context); + emitAndFixInvalidAsmCastLValue(LVal, OutputExpr, *this); + // Accept, even if we emitted an error diagnostic. + break; + } + case Expr::MLV_IncompleteType: + case Expr::MLV_IncompleteVoidType: + if (RequireCompleteType(OutputExpr->getBeginLoc(), Exprs[i]->getType(), + diag::err_dereference_incomplete_type)) + return StmtError(); + LLVM_FALLTHROUGH; + default: + return StmtError(Diag(OutputExpr->getBeginLoc(), + diag::err_asm_invalid_lvalue_in_output) + << OutputExpr->getSourceRange()); + } + + unsigned Size = Context.getTypeSize(OutputExpr->getType()); + if (!Context.getTargetInfo().validateOutputSize(Literal->getString(), + Size)) { + targetDiag(OutputExpr->getBeginLoc(), diag::err_asm_invalid_output_size) + << Info.getConstraintStr(); + return new (Context) + GCCAsmStmt(Context, AsmLoc, IsSimple, IsVolatile, NumOutputs, + NumInputs, Names, Constraints, Exprs.data(), AsmString, + NumClobbers, Clobbers, NumLabels, RParenLoc); + } + } + + SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; + + for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { + StringLiteral *Literal = Constraints[i]; + assert(Literal->isAscii()); + + StringRef InputName; + if (Names[i]) + InputName = Names[i]->getName(); + + TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); + if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos, + Info)) { + targetDiag(Literal->getBeginLoc(), diag::err_asm_invalid_input_constraint) + << Info.getConstraintStr(); + return new (Context) + GCCAsmStmt(Context, AsmLoc, IsSimple, IsVolatile, NumOutputs, + NumInputs, Names, Constraints, Exprs.data(), AsmString, + NumClobbers, Clobbers, NumLabels, RParenLoc); + } + + ExprResult ER = CheckPlaceholderExpr(Exprs[i]); + if (ER.isInvalid()) + return StmtError(); + Exprs[i] = ER.get(); + + Expr *InputExpr = Exprs[i]; + + // Referring to parameters is not allowed in naked functions. + if (CheckNakedParmReference(InputExpr, *this)) + return StmtError(); + + // Check that the input expression is compatible with memory constraint. + if (Info.allowsMemory() && + checkExprMemoryConstraintCompat(*this, InputExpr, Info, true)) + return StmtError(); + + // Only allow void types for memory constraints. + if (Info.allowsMemory() && !Info.allowsRegister()) { + if (CheckAsmLValue(InputExpr, *this)) + return StmtError(Diag(InputExpr->getBeginLoc(), + diag::err_asm_invalid_lvalue_in_input) + << Info.getConstraintStr() + << InputExpr->getSourceRange()); + } else if (Info.requiresImmediateConstant() && !Info.allowsRegister()) { + if (!InputExpr->isValueDependent()) { + Expr::EvalResult EVResult; + if (InputExpr->EvaluateAsRValue(EVResult, Context, true)) { + // For compatibility with GCC, we also allow pointers that would be + // integral constant expressions if they were cast to int. + llvm::APSInt IntResult; + if (EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(), + Context)) + if (!Info.isValidAsmImmediate(IntResult)) + return StmtError(Diag(InputExpr->getBeginLoc(), + diag::err_invalid_asm_value_for_constraint) + << IntResult.toString(10) + << Info.getConstraintStr() + << InputExpr->getSourceRange()); + } + } + + } else { + ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); + if (Result.isInvalid()) + return StmtError(); + + Exprs[i] = Result.get(); + } + + if (Info.allowsRegister()) { + if (InputExpr->getType()->isVoidType()) { + return StmtError( + Diag(InputExpr->getBeginLoc(), diag::err_asm_invalid_type_in_input) + << InputExpr->getType() << Info.getConstraintStr() + << InputExpr->getSourceRange()); + } + } + + InputConstraintInfos.push_back(Info); + + const Type *Ty = Exprs[i]->getType().getTypePtr(); + if (Ty->isDependentType()) + continue; + + if (!Ty->isVoidType() || !Info.allowsMemory()) + if (RequireCompleteType(InputExpr->getBeginLoc(), Exprs[i]->getType(), + diag::err_dereference_incomplete_type)) + return StmtError(); + + unsigned Size = Context.getTypeSize(Ty); + if (!Context.getTargetInfo().validateInputSize(Literal->getString(), + Size)) + return StmtResult( + targetDiag(InputExpr->getBeginLoc(), diag::err_asm_invalid_input_size) + << Info.getConstraintStr()); + } + + // Check that the clobbers are valid. + for (unsigned i = 0; i != NumClobbers; i++) { + StringLiteral *Literal = Clobbers[i]; + assert(Literal->isAscii()); + + StringRef Clobber = Literal->getString(); + + if (!Context.getTargetInfo().isValidClobber(Clobber)) { + targetDiag(Literal->getBeginLoc(), diag::err_asm_unknown_register_name) + << Clobber; + return new (Context) + GCCAsmStmt(Context, AsmLoc, IsSimple, IsVolatile, NumOutputs, + NumInputs, Names, Constraints, Exprs.data(), AsmString, + NumClobbers, Clobbers, NumLabels, RParenLoc); + } + } + + GCCAsmStmt *NS = + new (Context) GCCAsmStmt(Context, AsmLoc, IsSimple, IsVolatile, NumOutputs, + NumInputs, Names, Constraints, Exprs.data(), + AsmString, NumClobbers, Clobbers, NumLabels, + RParenLoc); + // Validate the asm string, ensuring it makes sense given the operands we + // have. + SmallVector<GCCAsmStmt::AsmStringPiece, 8> Pieces; + unsigned DiagOffs; + if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { + targetDiag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) + << AsmString->getSourceRange(); + return NS; + } + + // Validate constraints and modifiers. + for (unsigned i = 0, e = Pieces.size(); i != e; ++i) { + GCCAsmStmt::AsmStringPiece &Piece = Pieces[i]; + if (!Piece.isOperand()) continue; + + // Look for the correct constraint index. + unsigned ConstraintIdx = Piece.getOperandNo(); + // Labels are the last in the Exprs list. + if (NS->isAsmGoto() && ConstraintIdx >= NS->getNumInputs()) + continue; + unsigned NumOperands = NS->getNumOutputs() + NS->getNumInputs(); + // Look for the (ConstraintIdx - NumOperands + 1)th constraint with + // modifier '+'. + if (ConstraintIdx >= NumOperands) { + unsigned I = 0, E = NS->getNumOutputs(); + + for (unsigned Cnt = ConstraintIdx - NumOperands; I != E; ++I) + if (OutputConstraintInfos[I].isReadWrite() && Cnt-- == 0) { + ConstraintIdx = I; + break; + } + + assert(I != E && "Invalid operand number should have been caught in " + " AnalyzeAsmString"); + } + + // Now that we have the right indexes go ahead and check. + StringLiteral *Literal = Constraints[ConstraintIdx]; + const Type *Ty = Exprs[ConstraintIdx]->getType().getTypePtr(); + if (Ty->isDependentType() || Ty->isIncompleteType()) + continue; + + unsigned Size = Context.getTypeSize(Ty); + std::string SuggestedModifier; + if (!Context.getTargetInfo().validateConstraintModifier( + Literal->getString(), Piece.getModifier(), Size, + SuggestedModifier)) { + targetDiag(Exprs[ConstraintIdx]->getBeginLoc(), + diag::warn_asm_mismatched_size_modifier); + + if (!SuggestedModifier.empty()) { + auto B = targetDiag(Piece.getRange().getBegin(), + diag::note_asm_missing_constraint_modifier) + << SuggestedModifier; + SuggestedModifier = "%" + SuggestedModifier + Piece.getString(); + B << FixItHint::CreateReplacement(Piece.getRange(), SuggestedModifier); + } + } + } + + // Validate tied input operands for type mismatches. + unsigned NumAlternatives = ~0U; + for (unsigned i = 0, e = OutputConstraintInfos.size(); i != e; ++i) { + TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i]; + StringRef ConstraintStr = Info.getConstraintStr(); + unsigned AltCount = ConstraintStr.count(',') + 1; + if (NumAlternatives == ~0U) { + NumAlternatives = AltCount; + } else if (NumAlternatives != AltCount) { + targetDiag(NS->getOutputExpr(i)->getBeginLoc(), + diag::err_asm_unexpected_constraint_alternatives) + << NumAlternatives << AltCount; + return NS; + } + } + SmallVector<size_t, 4> InputMatchedToOutput(OutputConstraintInfos.size(), + ~0U); + for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { + TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; + StringRef ConstraintStr = Info.getConstraintStr(); + unsigned AltCount = ConstraintStr.count(',') + 1; + if (NumAlternatives == ~0U) { + NumAlternatives = AltCount; + } else if (NumAlternatives != AltCount) { + targetDiag(NS->getInputExpr(i)->getBeginLoc(), + diag::err_asm_unexpected_constraint_alternatives) + << NumAlternatives << AltCount; + return NS; + } + + // If this is a tied constraint, verify that the output and input have + // either exactly the same type, or that they are int/ptr operands with the + // same size (int/long, int*/long, are ok etc). + if (!Info.hasTiedOperand()) continue; + + unsigned TiedTo = Info.getTiedOperand(); + unsigned InputOpNo = i+NumOutputs; + Expr *OutputExpr = Exprs[TiedTo]; + Expr *InputExpr = Exprs[InputOpNo]; + + // Make sure no more than one input constraint matches each output. + assert(TiedTo < InputMatchedToOutput.size() && "TiedTo value out of range"); + if (InputMatchedToOutput[TiedTo] != ~0U) { + targetDiag(NS->getInputExpr(i)->getBeginLoc(), + diag::err_asm_input_duplicate_match) + << TiedTo; + targetDiag(NS->getInputExpr(InputMatchedToOutput[TiedTo])->getBeginLoc(), + diag::note_asm_input_duplicate_first) + << TiedTo; + return NS; + } + InputMatchedToOutput[TiedTo] = i; + + if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent()) + continue; + + QualType InTy = InputExpr->getType(); + QualType OutTy = OutputExpr->getType(); + if (Context.hasSameType(InTy, OutTy)) + continue; // All types can be tied to themselves. + + // Decide if the input and output are in the same domain (integer/ptr or + // floating point. + enum AsmDomain { + AD_Int, AD_FP, AD_Other + } InputDomain, OutputDomain; + + if (InTy->isIntegerType() || InTy->isPointerType()) + InputDomain = AD_Int; + else if (InTy->isRealFloatingType()) + InputDomain = AD_FP; + else + InputDomain = AD_Other; + + if (OutTy->isIntegerType() || OutTy->isPointerType()) + OutputDomain = AD_Int; + else if (OutTy->isRealFloatingType()) + OutputDomain = AD_FP; + else + OutputDomain = AD_Other; + + // They are ok if they are the same size and in the same domain. This + // allows tying things like: + // void* to int* + // void* to int if they are the same size. + // double to long double if they are the same size. + // + uint64_t OutSize = Context.getTypeSize(OutTy); + uint64_t InSize = Context.getTypeSize(InTy); + if (OutSize == InSize && InputDomain == OutputDomain && + InputDomain != AD_Other) + continue; + + // If the smaller input/output operand is not mentioned in the asm string, + // then we can promote the smaller one to a larger input and the asm string + // won't notice. + bool SmallerValueMentioned = false; + + // If this is a reference to the input and if the input was the smaller + // one, then we have to reject this asm. + if (isOperandMentioned(InputOpNo, Pieces)) { + // This is a use in the asm string of the smaller operand. Since we + // codegen this by promoting to a wider value, the asm will get printed + // "wrong". + SmallerValueMentioned |= InSize < OutSize; + } + if (isOperandMentioned(TiedTo, Pieces)) { + // If this is a reference to the output, and if the output is the larger + // value, then it's ok because we'll promote the input to the larger type. + SmallerValueMentioned |= OutSize < InSize; + } + + // If the smaller value wasn't mentioned in the asm string, and if the + // output was a register, just extend the shorter one to the size of the + // larger one. + if (!SmallerValueMentioned && InputDomain != AD_Other && + OutputConstraintInfos[TiedTo].allowsRegister()) + continue; + + // Either both of the operands were mentioned or the smaller one was + // mentioned. One more special case that we'll allow: if the tied input is + // integer, unmentioned, and is a constant, then we'll allow truncating it + // down to the size of the destination. + if (InputDomain == AD_Int && OutputDomain == AD_Int && + !isOperandMentioned(InputOpNo, Pieces) && + InputExpr->isEvaluatable(Context)) { + CastKind castKind = + (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); + InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).get(); + Exprs[InputOpNo] = InputExpr; + NS->setInputExpr(i, InputExpr); + continue; + } + + targetDiag(InputExpr->getBeginLoc(), diag::err_asm_tying_incompatible_types) + << InTy << OutTy << OutputExpr->getSourceRange() + << InputExpr->getSourceRange(); + return NS; + } + + // Check for conflicts between clobber list and input or output lists + SourceLocation ConstraintLoc = + getClobberConflictLocation(Exprs, Constraints, Clobbers, NumClobbers, + NumLabels, + Context.getTargetInfo(), Context); + if (ConstraintLoc.isValid()) + targetDiag(ConstraintLoc, diag::error_inoutput_conflict_with_clobber); + + // Check for duplicate asm operand name between input, output and label lists. + typedef std::pair<StringRef , Expr *> NamedOperand; + SmallVector<NamedOperand, 4> NamedOperandList; + for (unsigned i = 0, e = NumOutputs + NumInputs + NumLabels; i != e; ++i) + if (Names[i]) + NamedOperandList.emplace_back( + std::make_pair(Names[i]->getName(), Exprs[i])); + // Sort NamedOperandList. + std::stable_sort(NamedOperandList.begin(), NamedOperandList.end(), + [](const NamedOperand &LHS, const NamedOperand &RHS) { + return LHS.first < RHS.first; + }); + // Find adjacent duplicate operand. + SmallVector<NamedOperand, 4>::iterator Found = + std::adjacent_find(begin(NamedOperandList), end(NamedOperandList), + [](const NamedOperand &LHS, const NamedOperand &RHS) { + return LHS.first == RHS.first; + }); + if (Found != NamedOperandList.end()) { + Diag((Found + 1)->second->getBeginLoc(), + diag::error_duplicate_asm_operand_name) + << (Found + 1)->first; + Diag(Found->second->getBeginLoc(), diag::note_duplicate_asm_operand_name) + << Found->first; + return StmtError(); + } + if (NS->isAsmGoto()) + setFunctionHasBranchIntoScope(); + return NS; +} + +void Sema::FillInlineAsmIdentifierInfo(Expr *Res, + llvm::InlineAsmIdentifierInfo &Info) { + QualType T = Res->getType(); + Expr::EvalResult Eval; + if (T->isFunctionType() || T->isDependentType()) + return Info.setLabel(Res); + if (Res->isRValue()) { + if (isa<clang::EnumType>(T) && Res->EvaluateAsRValue(Eval, Context)) + return Info.setEnum(Eval.Val.getInt().getSExtValue()); + return Info.setLabel(Res); + } + unsigned Size = Context.getTypeSizeInChars(T).getQuantity(); + unsigned Type = Size; + if (const auto *ATy = Context.getAsArrayType(T)) + Type = Context.getTypeSizeInChars(ATy->getElementType()).getQuantity(); + bool IsGlobalLV = false; + if (Res->EvaluateAsLValue(Eval, Context)) + IsGlobalLV = Eval.isGlobalLValue(); + Info.setVar(Res, IsGlobalLV, Size, Type); +} + +ExprResult Sema::LookupInlineAsmIdentifier(CXXScopeSpec &SS, + SourceLocation TemplateKWLoc, + UnqualifiedId &Id, + bool IsUnevaluatedContext) { + + if (IsUnevaluatedContext) + PushExpressionEvaluationContext( + ExpressionEvaluationContext::UnevaluatedAbstract, + ReuseLambdaContextDecl); + + ExprResult Result = ActOnIdExpression(getCurScope(), SS, TemplateKWLoc, Id, + /*trailing lparen*/ false, + /*is & operand*/ false, + /*CorrectionCandidateCallback=*/nullptr, + /*IsInlineAsmIdentifier=*/ true); + + if (IsUnevaluatedContext) + PopExpressionEvaluationContext(); + + if (!Result.isUsable()) return Result; + + Result = CheckPlaceholderExpr(Result.get()); + if (!Result.isUsable()) return Result; + + // Referring to parameters is not allowed in naked functions. + if (CheckNakedParmReference(Result.get(), *this)) + return ExprError(); + + QualType T = Result.get()->getType(); + + if (T->isDependentType()) { + return Result; + } + + // Any sort of function type is fine. + if (T->isFunctionType()) { + return Result; + } + + // Otherwise, it needs to be a complete type. + if (RequireCompleteExprType(Result.get(), diag::err_asm_incomplete_type)) { + return ExprError(); + } + + return Result; +} + +bool Sema::LookupInlineAsmField(StringRef Base, StringRef Member, + unsigned &Offset, SourceLocation AsmLoc) { + Offset = 0; + SmallVector<StringRef, 2> Members; + Member.split(Members, "."); + + NamedDecl *FoundDecl = nullptr; + + // MS InlineAsm uses 'this' as a base + if (getLangOpts().CPlusPlus && Base.equals("this")) { + if (const Type *PT = getCurrentThisType().getTypePtrOrNull()) + FoundDecl = PT->getPointeeType()->getAsTagDecl(); + } else { + LookupResult BaseResult(*this, &Context.Idents.get(Base), SourceLocation(), + LookupOrdinaryName); + if (LookupName(BaseResult, getCurScope()) && BaseResult.isSingleResult()) + FoundDecl = BaseResult.getFoundDecl(); + } + + if (!FoundDecl) + return true; + + for (StringRef NextMember : Members) { + const RecordType *RT = nullptr; + if (VarDecl *VD = dyn_cast<VarDecl>(FoundDecl)) + RT = VD->getType()->getAs<RecordType>(); + else if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(FoundDecl)) { + MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false); + // MS InlineAsm often uses struct pointer aliases as a base + QualType QT = TD->getUnderlyingType(); + if (const auto *PT = QT->getAs<PointerType>()) + QT = PT->getPointeeType(); + RT = QT->getAs<RecordType>(); + } else if (TypeDecl *TD = dyn_cast<TypeDecl>(FoundDecl)) + RT = TD->getTypeForDecl()->getAs<RecordType>(); + else if (FieldDecl *TD = dyn_cast<FieldDecl>(FoundDecl)) + RT = TD->getType()->getAs<RecordType>(); + if (!RT) + return true; + + if (RequireCompleteType(AsmLoc, QualType(RT, 0), + diag::err_asm_incomplete_type)) + return true; + + LookupResult FieldResult(*this, &Context.Idents.get(NextMember), + SourceLocation(), LookupMemberName); + + if (!LookupQualifiedName(FieldResult, RT->getDecl())) + return true; + + if (!FieldResult.isSingleResult()) + return true; + FoundDecl = FieldResult.getFoundDecl(); + + // FIXME: Handle IndirectFieldDecl? + FieldDecl *FD = dyn_cast<FieldDecl>(FoundDecl); + if (!FD) + return true; + + const ASTRecordLayout &RL = Context.getASTRecordLayout(RT->getDecl()); + unsigned i = FD->getFieldIndex(); + CharUnits Result = Context.toCharUnitsFromBits(RL.getFieldOffset(i)); + Offset += (unsigned)Result.getQuantity(); + } + + return false; +} + +ExprResult +Sema::LookupInlineAsmVarDeclField(Expr *E, StringRef Member, + SourceLocation AsmLoc) { + + QualType T = E->getType(); + if (T->isDependentType()) { + DeclarationNameInfo NameInfo; + NameInfo.setLoc(AsmLoc); + NameInfo.setName(&Context.Idents.get(Member)); + return CXXDependentScopeMemberExpr::Create( + Context, E, T, /*IsArrow=*/false, AsmLoc, NestedNameSpecifierLoc(), + SourceLocation(), + /*FirstQualifierFoundInScope=*/nullptr, NameInfo, /*TemplateArgs=*/nullptr); + } + + const RecordType *RT = T->getAs<RecordType>(); + // FIXME: Diagnose this as field access into a scalar type. + if (!RT) + return ExprResult(); + + LookupResult FieldResult(*this, &Context.Idents.get(Member), AsmLoc, + LookupMemberName); + + if (!LookupQualifiedName(FieldResult, RT->getDecl())) + return ExprResult(); + + // Only normal and indirect field results will work. + ValueDecl *FD = dyn_cast<FieldDecl>(FieldResult.getFoundDecl()); + if (!FD) + FD = dyn_cast<IndirectFieldDecl>(FieldResult.getFoundDecl()); + if (!FD) + return ExprResult(); + + // Make an Expr to thread through OpDecl. + ExprResult Result = BuildMemberReferenceExpr( + E, E->getType(), AsmLoc, /*IsArrow=*/false, CXXScopeSpec(), + SourceLocation(), nullptr, FieldResult, nullptr, nullptr); + + return Result; +} + +StmtResult Sema::ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc, + ArrayRef<Token> AsmToks, + StringRef AsmString, + unsigned NumOutputs, unsigned NumInputs, + ArrayRef<StringRef> Constraints, + ArrayRef<StringRef> Clobbers, + ArrayRef<Expr*> Exprs, + SourceLocation EndLoc) { + bool IsSimple = (NumOutputs != 0 || NumInputs != 0); + setFunctionHasBranchProtectedScope(); + MSAsmStmt *NS = + new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, IsSimple, + /*IsVolatile*/ true, AsmToks, NumOutputs, NumInputs, + Constraints, Exprs, AsmString, + Clobbers, EndLoc); + return NS; +} + +LabelDecl *Sema::GetOrCreateMSAsmLabel(StringRef ExternalLabelName, + SourceLocation Location, + bool AlwaysCreate) { + LabelDecl* Label = LookupOrCreateLabel(PP.getIdentifierInfo(ExternalLabelName), + Location); + + if (Label->isMSAsmLabel()) { + // If we have previously created this label implicitly, mark it as used. + Label->markUsed(Context); + } else { + // Otherwise, insert it, but only resolve it if we have seen the label itself. + std::string InternalName; + llvm::raw_string_ostream OS(InternalName); + // Create an internal name for the label. The name should not be a valid + // mangled name, and should be unique. We use a dot to make the name an + // invalid mangled name. We use LLVM's inline asm ${:uid} escape so that a + // unique label is generated each time this blob is emitted, even after + // inlining or LTO. + OS << "__MSASMLABEL_.${:uid}__"; + for (char C : ExternalLabelName) { + OS << C; + // We escape '$' in asm strings by replacing it with "$$" + if (C == '$') + OS << '$'; + } + Label->setMSAsmLabel(OS.str()); + } + if (AlwaysCreate) { + // The label might have been created implicitly from a previously encountered + // goto statement. So, for both newly created and looked up labels, we mark + // them as resolved. + Label->setMSAsmLabelResolved(); + } + // Adjust their location for being able to generate accurate diagnostics. + Label->setLocation(Location); + + return Label; +} |