maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/clang/lib/Sema/SemaStmtAsm.cpp

630 lines
22 KiB
C++
Raw Blame History

//===--- SemaStmtAsm.cpp - Semantic Analysis for Asm Statements -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements semantic analysis for inline asm statements.
//
//===----------------------------------------------------------------------===//
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstPrinter.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCTargetAsmParser.h"
#include "llvm/MC/MCParser/MCAsmLexer.h"
#include "llvm/MC/MCParser/MCAsmParser.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
using namespace clang;
using namespace sema;
/// 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(const 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()) {
if (!S.getLangOpts().HeinousExtensions)
S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue)
<< E->getSourceRange();
else
S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue)
<< E->getSourceRange();
// 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<AsmStmt::AsmStringPiece> AsmStrPieces) {
for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) {
const AsmStmt::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;
}
StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple,
bool IsVolatile, unsigned NumOutputs,
unsigned NumInputs, IdentifierInfo **Names,
MultiExprArg constraints, MultiExprArg exprs,
Expr *asmString, MultiExprArg clobbers,
SourceLocation RParenLoc) {
unsigned NumClobbers = clobbers.size();
StringLiteral **Constraints =
reinterpret_cast<StringLiteral**>(constraints.get());
Expr **Exprs = exprs.get();
StringLiteral *AsmString = cast<StringLiteral>(asmString);
StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get());
SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
// The parser verifies that there is a string literal here.
if (!AsmString->isAscii())
return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character)
<< AsmString->getSourceRange());
for (unsigned i = 0; i != NumOutputs; i++) {
StringLiteral *Literal = Constraints[i];
if (!Literal->isAscii())
return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
<< Literal->getSourceRange());
StringRef OutputName;
if (Names[i])
OutputName = Names[i]->getName();
TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName);
if (!Context.getTargetInfo().validateOutputConstraint(Info))
return StmtError(Diag(Literal->getLocStart(),
diag::err_asm_invalid_output_constraint)
<< Info.getConstraintStr());
// Check that the output exprs are valid lvalues.
Expr *OutputExpr = Exprs[i];
if (CheckAsmLValue(OutputExpr, *this)) {
return StmtError(Diag(OutputExpr->getLocStart(),
diag::err_asm_invalid_lvalue_in_output)
<< OutputExpr->getSourceRange());
}
OutputConstraintInfos.push_back(Info);
}
SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
StringLiteral *Literal = Constraints[i];
if (!Literal->isAscii())
return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
<< Literal->getSourceRange());
StringRef InputName;
if (Names[i])
InputName = Names[i]->getName();
TargetInfo::ConstraintInfo Info(Literal->getString(), InputName);
if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(),
NumOutputs, Info)) {
return StmtError(Diag(Literal->getLocStart(),
diag::err_asm_invalid_input_constraint)
<< Info.getConstraintStr());
}
Expr *InputExpr = Exprs[i];
// Only allow void types for memory constraints.
if (Info.allowsMemory() && !Info.allowsRegister()) {
if (CheckAsmLValue(InputExpr, *this))
return StmtError(Diag(InputExpr->getLocStart(),
diag::err_asm_invalid_lvalue_in_input)
<< Info.getConstraintStr()
<< InputExpr->getSourceRange());
}
if (Info.allowsRegister()) {
if (InputExpr->getType()->isVoidType()) {
return StmtError(Diag(InputExpr->getLocStart(),
diag::err_asm_invalid_type_in_input)
<< InputExpr->getType() << Info.getConstraintStr()
<< InputExpr->getSourceRange());
}
}
ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]);
if (Result.isInvalid())
return StmtError();
Exprs[i] = Result.take();
InputConstraintInfos.push_back(Info);
}
// Check that the clobbers are valid.
for (unsigned i = 0; i != NumClobbers; i++) {
StringLiteral *Literal = Clobbers[i];
if (!Literal->isAscii())
return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
<< Literal->getSourceRange());
StringRef Clobber = Literal->getString();
if (!Context.getTargetInfo().isValidClobber(Clobber))
return StmtError(Diag(Literal->getLocStart(),
diag::err_asm_unknown_register_name) << Clobber);
}
AsmStmt *NS =
new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, NumOutputs,
NumInputs, Names, Constraints, Exprs, AsmString,
NumClobbers, Clobbers, RParenLoc);
// Validate the asm string, ensuring it makes sense given the operands we
// have.
SmallVector<AsmStmt::AsmStringPiece, 8> Pieces;
unsigned DiagOffs;
if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) {
Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID)
<< AsmString->getSourceRange();
return StmtError();
}
// Validate tied input operands for type mismatches.
for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
// 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];
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).take();
Exprs[InputOpNo] = InputExpr;
NS->setInputExpr(i, InputExpr);
continue;
}
Diag(InputExpr->getLocStart(),
diag::err_asm_tying_incompatible_types)
<< InTy << OutTy << OutputExpr->getSourceRange()
<< InputExpr->getSourceRange();
return StmtError();
}
return Owned(NS);
}
// isMSAsmKeyword - Return true if this is an MS-style inline asm keyword. These
// require special handling.
static bool isMSAsmKeyword(StringRef Name) {
bool Ret = llvm::StringSwitch<bool>(Name)
.Cases("EVEN", "ALIGN", true) // Alignment directives.
.Cases("LENGTH", "SIZE", "TYPE", true) // Type and variable sizes.
.Case("_emit", true) // _emit Pseudoinstruction.
.Default(false);
return Ret;
}
static StringRef getSpelling(Sema &SemaRef, Token AsmTok) {
StringRef Asm;
SmallString<512> TokenBuf;
TokenBuf.resize(512);
bool StringInvalid = false;
Asm = SemaRef.PP.getSpelling(AsmTok, TokenBuf, &StringInvalid);
assert (!StringInvalid && "Expected valid string!");
return Asm;
}
static void patchMSAsmStrings(Sema &SemaRef, bool &IsSimple,
SourceLocation AsmLoc,
ArrayRef<Token> AsmToks,
const TargetInfo &TI,
std::vector<llvm::BitVector> &AsmRegs,
std::vector<llvm::BitVector> &AsmNames,
std::vector<std::string> &AsmStrings) {
assert (!AsmToks.empty() && "Didn't expect an empty AsmToks!");
// Assume simple asm stmt until we parse a non-register identifer (or we just
// need to bail gracefully).
IsSimple = true;
SmallString<512> Asm;
unsigned NumAsmStrings = 0;
for (unsigned i = 0, e = AsmToks.size(); i != e; ++i) {
// Determine if this should be considered a new asm.
bool isNewAsm = i == 0 || AsmToks[i].isAtStartOfLine() ||
AsmToks[i].is(tok::kw_asm);
// Emit the previous asm string.
if (i && isNewAsm) {
AsmStrings[NumAsmStrings++] = Asm.c_str();
if (AsmToks[i].is(tok::kw_asm)) {
++i; // Skip __asm
assert (i != e && "Expected another token.");
}
}
// Start a new asm string with the opcode.
if (isNewAsm) {
AsmRegs[NumAsmStrings].resize(AsmToks.size());
AsmNames[NumAsmStrings].resize(AsmToks.size());
StringRef Piece = AsmToks[i].getIdentifierInfo()->getName();
// MS-style inline asm keywords require special handling.
if (isMSAsmKeyword(Piece))
IsSimple = false;
// TODO: Verify this is a valid opcode.
Asm = Piece;
continue;
}
if (i && AsmToks[i].hasLeadingSpace())
Asm += ' ';
// Check the operand(s).
switch (AsmToks[i].getKind()) {
default:
IsSimple = false;
Asm += getSpelling(SemaRef, AsmToks[i]);
break;
case tok::comma: Asm += ","; break;
case tok::colon: Asm += ":"; break;
case tok::l_square: Asm += "["; break;
case tok::r_square: Asm += "]"; break;
case tok::l_brace: Asm += "{"; break;
case tok::r_brace: Asm += "}"; break;
case tok::numeric_constant:
Asm += getSpelling(SemaRef, AsmToks[i]);
break;
case tok::identifier: {
IdentifierInfo *II = AsmToks[i].getIdentifierInfo();
StringRef Name = II->getName();
// Valid register?
if (TI.isValidGCCRegisterName(Name)) {
AsmRegs[NumAsmStrings].set(i);
Asm += Name;
break;
}
IsSimple = false;
// MS-style inline asm keywords require special handling.
if (isMSAsmKeyword(Name)) {
IsSimple = false;
Asm += Name;
break;
}
// Lookup the identifier.
// TODO: Someone with more experience with clang should verify this the
// proper way of doing a symbol lookup.
DeclarationName DeclName(II);
Scope *CurScope = SemaRef.getCurScope();
LookupResult R(SemaRef, DeclName, AsmLoc, Sema::LookupOrdinaryName);
if (!SemaRef.LookupName(R, CurScope, false/*AllowBuiltinCreation*/))
break;
assert (R.isSingleResult() && "Expected a single result?!");
NamedDecl *Decl = R.getFoundDecl();
switch (Decl->getKind()) {
default:
assert(0 && "Unknown decl kind.");
break;
case Decl::Var: {
case Decl::ParmVar:
AsmNames[NumAsmStrings].set(i);
VarDecl *Var = cast<VarDecl>(Decl);
QualType Ty = Var->getType();
(void)Ty; // Avoid warning.
// TODO: Patch identifier with valid operand. One potential idea is to
// probe the backend with type information to guess the possible
// operand.
break;
}
}
break;
}
}
}
// Emit the final (and possibly only) asm string.
AsmStrings[NumAsmStrings] = Asm.c_str();
}
// Build the unmodified MSAsmString.
static std::string buildMSAsmString(Sema &SemaRef,
ArrayRef<Token> AsmToks,
unsigned &NumAsmStrings) {
assert (!AsmToks.empty() && "Didn't expect an empty AsmToks!");
NumAsmStrings = 0;
SmallString<512> Asm;
for (unsigned i = 0, e = AsmToks.size(); i < e; ++i) {
bool isNewAsm = i == 0 || AsmToks[i].isAtStartOfLine() ||
AsmToks[i].is(tok::kw_asm);
if (isNewAsm) {
++NumAsmStrings;
if (i)
Asm += '\n';
if (AsmToks[i].is(tok::kw_asm)) {
i++; // Skip __asm
assert (i != e && "Expected another token");
}
}
if (i && AsmToks[i].hasLeadingSpace() && !isNewAsm)
Asm += ' ';
Asm += getSpelling(SemaRef, AsmToks[i]);
}
return Asm.c_str();
}
StmtResult Sema::ActOnMSAsmStmt(SourceLocation AsmLoc,
SourceLocation LBraceLoc,
ArrayRef<Token> AsmToks,
SourceLocation EndLoc) {
// MS-style inline assembly is not fully supported, so emit a warning.
Diag(AsmLoc, diag::warn_unsupported_msasm);
SmallVector<StringRef,4> Clobbers;
std::set<std::string> ClobberRegs;
SmallVector<IdentifierInfo*, 4> Inputs;
SmallVector<IdentifierInfo*, 4> Outputs;
// Empty asm statements don't need to instantiate the AsmParser, etc.
if (AsmToks.empty()) {
StringRef AsmString;
MSAsmStmt *NS =
new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, /*IsSimple*/ true,
/*IsVolatile*/ true, AsmToks, Inputs, Outputs,
AsmString, Clobbers, EndLoc);
return Owned(NS);
}
unsigned NumAsmStrings;
std::string AsmString = buildMSAsmString(*this, AsmToks, NumAsmStrings);
bool IsSimple;
std::vector<llvm::BitVector> Regs;
std::vector<llvm::BitVector> Names;
std::vector<std::string> PatchedAsmStrings;
Regs.resize(NumAsmStrings);
Names.resize(NumAsmStrings);
PatchedAsmStrings.resize(NumAsmStrings);
// Rewrite operands to appease the AsmParser.
patchMSAsmStrings(*this, IsSimple, AsmLoc, AsmToks,
Context.getTargetInfo(), Regs, Names, PatchedAsmStrings);
// patchMSAsmStrings doesn't correctly patch non-simple asm statements.
if (!IsSimple) {
MSAsmStmt *NS =
new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, /*IsSimple*/ true,
/*IsVolatile*/ true, AsmToks, Inputs, Outputs,
AsmString, Clobbers, EndLoc);
return Owned(NS);
}
// Initialize targets and assembly printers/parsers.
llvm::InitializeAllTargetInfos();
llvm::InitializeAllTargetMCs();
llvm::InitializeAllAsmParsers();
// Get the target specific parser.
std::string Error;
const std::string &TT = Context.getTargetInfo().getTriple().getTriple();
const llvm::Target *TheTarget(llvm::TargetRegistry::lookupTarget(TT, Error));
OwningPtr<llvm::MCAsmInfo> MAI(TheTarget->createMCAsmInfo(TT));
OwningPtr<llvm::MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TT));
OwningPtr<llvm::MCObjectFileInfo> MOFI(new llvm::MCObjectFileInfo());
OwningPtr<llvm::MCSubtargetInfo>
STI(TheTarget->createMCSubtargetInfo(TT, "", ""));
for (unsigned i = 0, e = PatchedAsmStrings.size(); i != e; ++i) {
llvm::SourceMgr SrcMgr;
llvm::MCContext Ctx(*MAI, *MRI, MOFI.get(), &SrcMgr);
llvm::MemoryBuffer *Buffer =
llvm::MemoryBuffer::getMemBuffer(PatchedAsmStrings[i], "<inline asm>");
// Tell SrcMgr about this buffer, which is what the parser will pick up.
SrcMgr.AddNewSourceBuffer(Buffer, llvm::SMLoc());
OwningPtr<llvm::MCStreamer> Str(createNullStreamer(Ctx));
OwningPtr<llvm::MCAsmParser>
Parser(createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));
OwningPtr<llvm::MCTargetAsmParser>
TargetParser(TheTarget->createMCAsmParser(*STI, *Parser));
// Change to the Intel dialect.
Parser->setAssemblerDialect(1);
Parser->setTargetParser(*TargetParser.get());
// Prime the lexer.
Parser->Lex();
// Parse the opcode.
StringRef IDVal;
Parser->ParseIdentifier(IDVal);
// Canonicalize the opcode to lower case.
SmallString<128> Opcode;
for (unsigned i = 0, e = IDVal.size(); i != e; ++i)
Opcode.push_back(tolower(IDVal[i]));
// Parse the operands.
llvm::SMLoc IDLoc;
SmallVector<llvm::MCParsedAsmOperand*, 8> Operands;
bool HadError = TargetParser->ParseInstruction(Opcode.str(), IDLoc,
Operands);
assert (!HadError && "Unexpected error parsing instruction");
// Match the MCInstr.
SmallVector<llvm::MCInst, 2> Instrs;
HadError = TargetParser->MatchInstruction(IDLoc, Operands, Instrs);
assert (!HadError && "Unexpected error matching instruction");
assert ((Instrs.size() == 1) && "Expected only a single instruction.");
// Get the instruction descriptor.
llvm::MCInst Inst = Instrs[0];
const llvm::MCInstrInfo *MII = TheTarget->createMCInstrInfo();
const llvm::MCInstrDesc &Desc = MII->get(Inst.getOpcode());
llvm::MCInstPrinter *IP =
TheTarget->createMCInstPrinter(1, *MAI, *MII, *MRI, *STI);
// Build the list of clobbers.
for (unsigned i = 0, e = Desc.getNumDefs(); i != e; ++i) {
const llvm::MCOperand &Op = Inst.getOperand(i);
if (!Op.isReg())
continue;
std::string Reg;
llvm::raw_string_ostream OS(Reg);
IP->printRegName(OS, Op.getReg());
StringRef Clobber(OS.str());
if (!Context.getTargetInfo().isValidClobber(Clobber))
return StmtError(Diag(AsmLoc, diag::err_asm_unknown_register_name) <<
Clobber);
ClobberRegs.insert(Reg);
}
}
for (std::set<std::string>::iterator I = ClobberRegs.begin(),
E = ClobberRegs.end(); I != E; ++I)
Clobbers.push_back(*I);
MSAsmStmt *NS =
new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, IsSimple,
/*IsVolatile*/ true, AsmToks, Inputs, Outputs,
AsmString, Clobbers, EndLoc);
return Owned(NS);
}
Reference in New Issue View Git Blame Copy Permalink