490 lines
18 KiB
C++
490 lines
18 KiB
C++
//===--- SemaStmtAsm.cpp - Semantic Analysis for Asm Statements -----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements semantic analysis for inline asm statements.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Sema/SemaInternal.h"
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#include "clang/AST/RecordLayout.h"
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#include "clang/AST/TypeLoc.h"
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#include "clang/Basic/TargetInfo.h"
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#include "clang/Sema/Initialization.h"
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#include "clang/Sema/Lookup.h"
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#include "clang/Sema/Scope.h"
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#include "clang/Sema/ScopeInfo.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/BitVector.h"
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#include "llvm/MC/MCParser/MCAsmParser.h"
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using namespace clang;
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using namespace sema;
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/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently
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/// ignore "noop" casts in places where an lvalue is required by an inline asm.
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/// We emulate this behavior when -fheinous-gnu-extensions is specified, but
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/// provide a strong guidance to not use it.
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///
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/// This method checks to see if the argument is an acceptable l-value and
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/// returns false if it is a case we can handle.
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static bool CheckAsmLValue(const Expr *E, Sema &S) {
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// Type dependent expressions will be checked during instantiation.
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if (E->isTypeDependent())
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return false;
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if (E->isLValue())
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return false; // Cool, this is an lvalue.
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// Okay, this is not an lvalue, but perhaps it is the result of a cast that we
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// are supposed to allow.
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const Expr *E2 = E->IgnoreParenNoopCasts(S.Context);
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if (E != E2 && E2->isLValue()) {
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if (!S.getLangOpts().HeinousExtensions)
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S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue)
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<< E->getSourceRange();
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else
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S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue)
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<< E->getSourceRange();
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// Accept, even if we emitted an error diagnostic.
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return false;
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}
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// None of the above, just randomly invalid non-lvalue.
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return true;
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}
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/// isOperandMentioned - Return true if the specified operand # is mentioned
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/// anywhere in the decomposed asm string.
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static bool isOperandMentioned(unsigned OpNo,
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ArrayRef<GCCAsmStmt::AsmStringPiece> AsmStrPieces) {
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for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) {
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const GCCAsmStmt::AsmStringPiece &Piece = AsmStrPieces[p];
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if (!Piece.isOperand()) continue;
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// If this is a reference to the input and if the input was the smaller
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// one, then we have to reject this asm.
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if (Piece.getOperandNo() == OpNo)
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return true;
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}
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return false;
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}
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StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
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bool IsVolatile, unsigned NumOutputs,
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unsigned NumInputs, IdentifierInfo **Names,
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MultiExprArg constraints, MultiExprArg Exprs,
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Expr *asmString, MultiExprArg clobbers,
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SourceLocation RParenLoc) {
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unsigned NumClobbers = clobbers.size();
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StringLiteral **Constraints =
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reinterpret_cast<StringLiteral**>(constraints.data());
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StringLiteral *AsmString = cast<StringLiteral>(asmString);
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StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.data());
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SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
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// The parser verifies that there is a string literal here.
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if (!AsmString->isAscii())
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return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character)
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<< AsmString->getSourceRange());
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for (unsigned i = 0; i != NumOutputs; i++) {
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StringLiteral *Literal = Constraints[i];
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if (!Literal->isAscii())
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return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
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<< Literal->getSourceRange());
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StringRef OutputName;
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if (Names[i])
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OutputName = Names[i]->getName();
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TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName);
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if (!Context.getTargetInfo().validateOutputConstraint(Info))
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return StmtError(Diag(Literal->getLocStart(),
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diag::err_asm_invalid_output_constraint)
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<< Info.getConstraintStr());
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// Check that the output exprs are valid lvalues.
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Expr *OutputExpr = Exprs[i];
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if (CheckAsmLValue(OutputExpr, *this))
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return StmtError(Diag(OutputExpr->getLocStart(),
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diag::err_asm_invalid_lvalue_in_output)
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<< OutputExpr->getSourceRange());
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if (RequireCompleteType(OutputExpr->getLocStart(), Exprs[i]->getType(),
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diag::err_dereference_incomplete_type))
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return StmtError();
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OutputConstraintInfos.push_back(Info);
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}
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SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
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for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
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StringLiteral *Literal = Constraints[i];
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if (!Literal->isAscii())
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return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
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<< Literal->getSourceRange());
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StringRef InputName;
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if (Names[i])
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InputName = Names[i]->getName();
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TargetInfo::ConstraintInfo Info(Literal->getString(), InputName);
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if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(),
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NumOutputs, Info)) {
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return StmtError(Diag(Literal->getLocStart(),
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diag::err_asm_invalid_input_constraint)
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<< Info.getConstraintStr());
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}
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Expr *InputExpr = Exprs[i];
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// Only allow void types for memory constraints.
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if (Info.allowsMemory() && !Info.allowsRegister()) {
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if (CheckAsmLValue(InputExpr, *this))
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return StmtError(Diag(InputExpr->getLocStart(),
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diag::err_asm_invalid_lvalue_in_input)
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<< Info.getConstraintStr()
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<< InputExpr->getSourceRange());
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}
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if (Info.allowsRegister()) {
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if (InputExpr->getType()->isVoidType()) {
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return StmtError(Diag(InputExpr->getLocStart(),
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diag::err_asm_invalid_type_in_input)
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<< InputExpr->getType() << Info.getConstraintStr()
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<< InputExpr->getSourceRange());
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}
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}
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ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]);
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if (Result.isInvalid())
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return StmtError();
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Exprs[i] = Result.get();
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InputConstraintInfos.push_back(Info);
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const Type *Ty = Exprs[i]->getType().getTypePtr();
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if (Ty->isDependentType())
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continue;
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if (!Ty->isVoidType() || !Info.allowsMemory())
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if (RequireCompleteType(InputExpr->getLocStart(), Exprs[i]->getType(),
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diag::err_dereference_incomplete_type))
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return StmtError();
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unsigned Size = Context.getTypeSize(Ty);
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if (!Context.getTargetInfo().validateInputSize(Literal->getString(),
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Size))
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return StmtError(Diag(InputExpr->getLocStart(),
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diag::err_asm_invalid_input_size)
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<< Info.getConstraintStr());
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}
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// Check that the clobbers are valid.
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for (unsigned i = 0; i != NumClobbers; i++) {
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StringLiteral *Literal = Clobbers[i];
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if (!Literal->isAscii())
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return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
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<< Literal->getSourceRange());
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StringRef Clobber = Literal->getString();
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if (!Context.getTargetInfo().isValidClobber(Clobber))
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return StmtError(Diag(Literal->getLocStart(),
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diag::err_asm_unknown_register_name) << Clobber);
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}
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GCCAsmStmt *NS =
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new (Context) GCCAsmStmt(Context, AsmLoc, IsSimple, IsVolatile, NumOutputs,
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NumInputs, Names, Constraints, Exprs.data(),
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AsmString, NumClobbers, Clobbers, RParenLoc);
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// Validate the asm string, ensuring it makes sense given the operands we
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// have.
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SmallVector<GCCAsmStmt::AsmStringPiece, 8> Pieces;
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unsigned DiagOffs;
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if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) {
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Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID)
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<< AsmString->getSourceRange();
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return StmtError();
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}
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// Validate constraints and modifiers.
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for (unsigned i = 0, e = Pieces.size(); i != e; ++i) {
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GCCAsmStmt::AsmStringPiece &Piece = Pieces[i];
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if (!Piece.isOperand()) continue;
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// Look for the correct constraint index.
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unsigned Idx = 0;
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unsigned ConstraintIdx = 0;
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for (unsigned i = 0, e = NS->getNumOutputs(); i != e; ++i, ++ConstraintIdx) {
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TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
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if (Idx == Piece.getOperandNo())
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break;
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++Idx;
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if (Info.isReadWrite()) {
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if (Idx == Piece.getOperandNo())
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break;
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++Idx;
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}
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}
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for (unsigned i = 0, e = NS->getNumInputs(); i != e; ++i, ++ConstraintIdx) {
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TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
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if (Idx == Piece.getOperandNo())
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break;
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++Idx;
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if (Info.isReadWrite()) {
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if (Idx == Piece.getOperandNo())
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break;
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++Idx;
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}
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}
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// Now that we have the right indexes go ahead and check.
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StringLiteral *Literal = Constraints[ConstraintIdx];
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const Type *Ty = Exprs[ConstraintIdx]->getType().getTypePtr();
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if (Ty->isDependentType() || Ty->isIncompleteType())
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continue;
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unsigned Size = Context.getTypeSize(Ty);
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if (!Context.getTargetInfo()
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.validateConstraintModifier(Literal->getString(), Piece.getModifier(),
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Size))
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Diag(Exprs[ConstraintIdx]->getLocStart(),
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diag::warn_asm_mismatched_size_modifier);
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}
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// Validate tied input operands for type mismatches.
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for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
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TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
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// If this is a tied constraint, verify that the output and input have
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// either exactly the same type, or that they are int/ptr operands with the
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// same size (int/long, int*/long, are ok etc).
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if (!Info.hasTiedOperand()) continue;
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unsigned TiedTo = Info.getTiedOperand();
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unsigned InputOpNo = i+NumOutputs;
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Expr *OutputExpr = Exprs[TiedTo];
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Expr *InputExpr = Exprs[InputOpNo];
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if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent())
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continue;
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QualType InTy = InputExpr->getType();
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QualType OutTy = OutputExpr->getType();
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if (Context.hasSameType(InTy, OutTy))
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continue; // All types can be tied to themselves.
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// Decide if the input and output are in the same domain (integer/ptr or
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// floating point.
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enum AsmDomain {
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AD_Int, AD_FP, AD_Other
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} InputDomain, OutputDomain;
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if (InTy->isIntegerType() || InTy->isPointerType())
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InputDomain = AD_Int;
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else if (InTy->isRealFloatingType())
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InputDomain = AD_FP;
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else
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InputDomain = AD_Other;
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if (OutTy->isIntegerType() || OutTy->isPointerType())
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OutputDomain = AD_Int;
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else if (OutTy->isRealFloatingType())
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OutputDomain = AD_FP;
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else
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OutputDomain = AD_Other;
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// They are ok if they are the same size and in the same domain. This
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// allows tying things like:
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// void* to int*
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// void* to int if they are the same size.
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// double to long double if they are the same size.
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//
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uint64_t OutSize = Context.getTypeSize(OutTy);
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uint64_t InSize = Context.getTypeSize(InTy);
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if (OutSize == InSize && InputDomain == OutputDomain &&
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InputDomain != AD_Other)
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continue;
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// If the smaller input/output operand is not mentioned in the asm string,
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// then we can promote the smaller one to a larger input and the asm string
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// won't notice.
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bool SmallerValueMentioned = false;
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// If this is a reference to the input and if the input was the smaller
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// one, then we have to reject this asm.
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if (isOperandMentioned(InputOpNo, Pieces)) {
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// This is a use in the asm string of the smaller operand. Since we
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// codegen this by promoting to a wider value, the asm will get printed
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// "wrong".
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SmallerValueMentioned |= InSize < OutSize;
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}
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if (isOperandMentioned(TiedTo, Pieces)) {
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// If this is a reference to the output, and if the output is the larger
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// value, then it's ok because we'll promote the input to the larger type.
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SmallerValueMentioned |= OutSize < InSize;
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}
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// If the smaller value wasn't mentioned in the asm string, and if the
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// output was a register, just extend the shorter one to the size of the
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// larger one.
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if (!SmallerValueMentioned && InputDomain != AD_Other &&
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OutputConstraintInfos[TiedTo].allowsRegister())
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continue;
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// Either both of the operands were mentioned or the smaller one was
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// mentioned. One more special case that we'll allow: if the tied input is
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// integer, unmentioned, and is a constant, then we'll allow truncating it
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// down to the size of the destination.
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if (InputDomain == AD_Int && OutputDomain == AD_Int &&
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!isOperandMentioned(InputOpNo, Pieces) &&
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InputExpr->isEvaluatable(Context)) {
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CastKind castKind =
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(OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast);
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InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).get();
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Exprs[InputOpNo] = InputExpr;
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NS->setInputExpr(i, InputExpr);
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continue;
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}
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Diag(InputExpr->getLocStart(),
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diag::err_asm_tying_incompatible_types)
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<< InTy << OutTy << OutputExpr->getSourceRange()
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<< InputExpr->getSourceRange();
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return StmtError();
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}
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return NS;
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}
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ExprResult Sema::LookupInlineAsmIdentifier(CXXScopeSpec &SS,
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SourceLocation TemplateKWLoc,
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UnqualifiedId &Id,
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llvm::InlineAsmIdentifierInfo &Info,
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bool IsUnevaluatedContext) {
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Info.clear();
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if (IsUnevaluatedContext)
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PushExpressionEvaluationContext(UnevaluatedAbstract,
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ReuseLambdaContextDecl);
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ExprResult Result = ActOnIdExpression(getCurScope(), SS, TemplateKWLoc, Id,
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/*trailing lparen*/ false,
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/*is & operand*/ false,
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/*CorrectionCandidateCallback=*/nullptr,
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/*IsInlineAsmIdentifier=*/ true);
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if (IsUnevaluatedContext)
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PopExpressionEvaluationContext();
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if (!Result.isUsable()) return Result;
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Result = CheckPlaceholderExpr(Result.get());
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if (!Result.isUsable()) return Result;
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QualType T = Result.get()->getType();
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// For now, reject dependent types.
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if (T->isDependentType()) {
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Diag(Id.getLocStart(), diag::err_asm_incomplete_type) << T;
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return ExprError();
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}
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// Any sort of function type is fine.
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if (T->isFunctionType()) {
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return Result;
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}
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// Otherwise, it needs to be a complete type.
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if (RequireCompleteExprType(Result.get(), diag::err_asm_incomplete_type)) {
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return ExprError();
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}
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// Compute the type size (and array length if applicable?).
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Info.Type = Info.Size = Context.getTypeSizeInChars(T).getQuantity();
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if (T->isArrayType()) {
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const ArrayType *ATy = Context.getAsArrayType(T);
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Info.Type = Context.getTypeSizeInChars(ATy->getElementType()).getQuantity();
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Info.Length = Info.Size / Info.Type;
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}
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// We can work with the expression as long as it's not an r-value.
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if (!Result.get()->isRValue())
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Info.IsVarDecl = true;
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return Result;
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}
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bool Sema::LookupInlineAsmField(StringRef Base, StringRef Member,
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unsigned &Offset, SourceLocation AsmLoc) {
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Offset = 0;
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LookupResult BaseResult(*this, &Context.Idents.get(Base), SourceLocation(),
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LookupOrdinaryName);
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if (!LookupName(BaseResult, getCurScope()))
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return true;
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if (!BaseResult.isSingleResult())
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return true;
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const RecordType *RT = nullptr;
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NamedDecl *FoundDecl = BaseResult.getFoundDecl();
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if (VarDecl *VD = dyn_cast<VarDecl>(FoundDecl))
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RT = VD->getType()->getAs<RecordType>();
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else if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(FoundDecl))
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RT = TD->getUnderlyingType()->getAs<RecordType>();
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else if (TypeDecl *TD = dyn_cast<TypeDecl>(FoundDecl))
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RT = TD->getTypeForDecl()->getAs<RecordType>();
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if (!RT)
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return true;
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if (RequireCompleteType(AsmLoc, QualType(RT, 0), 0))
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return true;
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LookupResult FieldResult(*this, &Context.Idents.get(Member), SourceLocation(),
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LookupMemberName);
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if (!LookupQualifiedName(FieldResult, RT->getDecl()))
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return true;
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// FIXME: Handle IndirectFieldDecl?
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FieldDecl *FD = dyn_cast<FieldDecl>(FieldResult.getFoundDecl());
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if (!FD)
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return true;
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const ASTRecordLayout &RL = Context.getASTRecordLayout(RT->getDecl());
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unsigned i = FD->getFieldIndex();
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CharUnits Result = Context.toCharUnitsFromBits(RL.getFieldOffset(i));
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Offset = (unsigned)Result.getQuantity();
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return false;
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}
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StmtResult Sema::ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
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ArrayRef<Token> AsmToks,
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StringRef AsmString,
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unsigned NumOutputs, unsigned NumInputs,
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ArrayRef<StringRef> Constraints,
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ArrayRef<StringRef> Clobbers,
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ArrayRef<Expr*> Exprs,
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SourceLocation EndLoc) {
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bool IsSimple = (NumOutputs != 0 || NumInputs != 0);
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MSAsmStmt *NS =
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new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, IsSimple,
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/*IsVolatile*/ true, AsmToks, NumOutputs, NumInputs,
|
|
Constraints, Exprs, AsmString,
|
|
Clobbers, EndLoc);
|
|
return NS;
|
|
}
|