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llvm-project/clang/lib/Parse/ParseStmtAsm.cpp

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//===---- ParseStmtAsm.cpp - Assembly Statement Parser --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements parsing for GCC and Microsoft inline assembly.
//
//===----------------------------------------------------------------------===//
#include "clang/Parse/Parser.h"
#include "RAIIObjectsForParser.h"
#include "clang/AST/ASTContext.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCInstPrinter.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCParser/MCAsmParser.h"
#include "llvm/MC/MCParser/MCTargetAsmParser.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCTargetOptions.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
using namespace clang;
namespace {
class ClangAsmParserCallback : public llvm::MCAsmParserSemaCallback {
Parser &TheParser;
SourceLocation AsmLoc;
StringRef AsmString;
/// The tokens we streamed into AsmString and handed off to MC.
ArrayRef<Token> AsmToks;
/// The offset of each token in AsmToks within AsmString.
ArrayRef<unsigned> AsmTokOffsets;
public:
ClangAsmParserCallback(Parser &P, SourceLocation Loc, StringRef AsmString,
ArrayRef<Token> Toks, ArrayRef<unsigned> Offsets)
: TheParser(P), AsmLoc(Loc), AsmString(AsmString), AsmToks(Toks),
AsmTokOffsets(Offsets) {
assert(AsmToks.size() == AsmTokOffsets.size());
}
void *LookupInlineAsmIdentifier(StringRef &LineBuf,
llvm::InlineAsmIdentifierInfo &Info,
bool IsUnevaluatedContext) override {
// Collect the desired tokens.
SmallVector<Token, 16> LineToks;
const Token *FirstOrigToken = nullptr;
findTokensForString(LineBuf, LineToks, FirstOrigToken);
unsigned NumConsumedToks;
ExprResult Result = TheParser.ParseMSAsmIdentifier(
LineToks, NumConsumedToks, &Info, IsUnevaluatedContext);
// If we consumed the entire line, tell MC that.
// Also do this if we consumed nothing as a way of reporting failure.
if (NumConsumedToks == 0 || NumConsumedToks == LineToks.size()) {
// By not modifying LineBuf, we're implicitly consuming it all.
// Otherwise, consume up to the original tokens.
} else {
assert(FirstOrigToken && "not using original tokens?");
// Since we're using original tokens, apply that offset.
assert(FirstOrigToken[NumConsumedToks].getLocation() ==
LineToks[NumConsumedToks].getLocation());
unsigned FirstIndex = FirstOrigToken - AsmToks.begin();
unsigned LastIndex = FirstIndex + NumConsumedToks - 1;
// The total length we've consumed is the relative offset
// of the last token we consumed plus its length.
unsigned TotalOffset =
(AsmTokOffsets[LastIndex] + AsmToks[LastIndex].getLength() -
AsmTokOffsets[FirstIndex]);
LineBuf = LineBuf.substr(0, TotalOffset);
}
// Initialize the "decl" with the lookup result.
Info.OpDecl = static_cast<void *>(Result.get());
return Info.OpDecl;
}
StringRef LookupInlineAsmLabel(StringRef Identifier, llvm::SourceMgr &LSM,
llvm::SMLoc Location,
bool Create) override {
SourceLocation Loc = translateLocation(LSM, Location);
LabelDecl *Label =
TheParser.getActions().GetOrCreateMSAsmLabel(Identifier, Loc, Create);
return Label->getMSAsmLabel();
}
bool LookupInlineAsmField(StringRef Base, StringRef Member,
unsigned &Offset) override {
return TheParser.getActions().LookupInlineAsmField(Base, Member, Offset,
AsmLoc);
}
static void DiagHandlerCallback(const llvm::SMDiagnostic &D, void *Context) {
((ClangAsmParserCallback *)Context)->handleDiagnostic(D);
}
private:
/// Collect the appropriate tokens for the given string.
void findTokensForString(StringRef Str, SmallVectorImpl<Token> &TempToks,
const Token *&FirstOrigToken) const {
// For now, assert that the string we're working with is a substring
// of what we gave to MC. This lets us use the original tokens.
assert(!std::less<const char *>()(Str.begin(), AsmString.begin()) &&
!std::less<const char *>()(AsmString.end(), Str.end()));
// Try to find a token whose offset matches the first token.
unsigned FirstCharOffset = Str.begin() - AsmString.begin();
const unsigned *FirstTokOffset = std::lower_bound(
AsmTokOffsets.begin(), AsmTokOffsets.end(), FirstCharOffset);
// For now, assert that the start of the string exactly
// corresponds to the start of a token.
assert(*FirstTokOffset == FirstCharOffset);
// Use all the original tokens for this line. (We assume the
// end of the line corresponds cleanly to a token break.)
unsigned FirstTokIndex = FirstTokOffset - AsmTokOffsets.begin();
FirstOrigToken = &AsmToks[FirstTokIndex];
unsigned LastCharOffset = Str.end() - AsmString.begin();
for (unsigned i = FirstTokIndex, e = AsmTokOffsets.size(); i != e; ++i) {
if (AsmTokOffsets[i] >= LastCharOffset)
break;
TempToks.push_back(AsmToks[i]);
}
}
SourceLocation translateLocation(const llvm::SourceMgr &LSM, llvm::SMLoc SMLoc) {
// Compute an offset into the inline asm buffer.
// FIXME: This isn't right if .macro is involved (but hopefully, no
// real-world code does that).
const llvm::MemoryBuffer *LBuf =
LSM.getMemoryBuffer(LSM.FindBufferContainingLoc(SMLoc));
unsigned Offset = SMLoc.getPointer() - LBuf->getBufferStart();
// Figure out which token that offset points into.
const unsigned *TokOffsetPtr =
std::lower_bound(AsmTokOffsets.begin(), AsmTokOffsets.end(), Offset);
unsigned TokIndex = TokOffsetPtr - AsmTokOffsets.begin();
unsigned TokOffset = *TokOffsetPtr;
// If we come up with an answer which seems sane, use it; otherwise,
// just point at the __asm keyword.
// FIXME: Assert the answer is sane once we handle .macro correctly.
SourceLocation Loc = AsmLoc;
if (TokIndex < AsmToks.size()) {
const Token &Tok = AsmToks[TokIndex];
Loc = Tok.getLocation();
Loc = Loc.getLocWithOffset(Offset - TokOffset);
}
return Loc;
}
void handleDiagnostic(const llvm::SMDiagnostic &D) {
const llvm::SourceMgr &LSM = *D.getSourceMgr();
SourceLocation Loc = translateLocation(LSM, D.getLoc());
TheParser.Diag(Loc, diag::err_inline_ms_asm_parsing) << D.getMessage();
}
};
}
/// Parse an identifier in an MS-style inline assembly block.
///
/// \param CastInfo - a void* so that we don't have to teach Parser.h
/// about the actual type.
ExprResult Parser::ParseMSAsmIdentifier(llvm::SmallVectorImpl<Token> &LineToks,
unsigned &NumLineToksConsumed,
void *CastInfo,
bool IsUnevaluatedContext) {
llvm::InlineAsmIdentifierInfo &Info =
*(llvm::InlineAsmIdentifierInfo *)CastInfo;
// Push a fake token on the end so that we don't overrun the token
// stream. We use ';' because it expression-parsing should never
// overrun it.
const tok::TokenKind EndOfStream = tok::semi;
Token EndOfStreamTok;
EndOfStreamTok.startToken();
EndOfStreamTok.setKind(EndOfStream);
LineToks.push_back(EndOfStreamTok);
// Also copy the current token over.
LineToks.push_back(Tok);
PP.EnterTokenStream(LineToks, /*DisableMacroExpansions*/ true);
// Clear the current token and advance to the first token in LineToks.
ConsumeAnyToken();
// Parse an optional scope-specifier if we're in C++.
CXXScopeSpec SS;
if (getLangOpts().CPlusPlus) {
ParseOptionalCXXScopeSpecifier(SS, nullptr, /*EnteringContext=*/false);
}
// Require an identifier here.
SourceLocation TemplateKWLoc;
UnqualifiedId Id;
bool Invalid = true;
ExprResult Result;
if (Tok.is(tok::kw_this)) {
Result = ParseCXXThis();
Invalid = false;
} else {
Invalid = ParseUnqualifiedId(SS,
/*EnteringContext=*/false,
/*AllowDestructorName=*/false,
/*AllowConstructorName=*/false,
/*ObjectType=*/nullptr, TemplateKWLoc, Id);
// Perform the lookup.
Result = Actions.LookupInlineAsmIdentifier(SS, TemplateKWLoc, Id, Info,
IsUnevaluatedContext);
}
// While the next two tokens are 'period' 'identifier', repeatedly parse it as
// a field access. We have to avoid consuming assembler directives that look
// like '.' 'else'.
while (Result.isUsable() && Tok.is(tok::period)) {
Token IdTok = PP.LookAhead(0);
if (IdTok.isNot(tok::identifier))
break;
ConsumeToken(); // Consume the period.
IdentifierInfo *Id = Tok.getIdentifierInfo();
ConsumeToken(); // Consume the identifier.
Result = Actions.LookupInlineAsmVarDeclField(Result.get(), Id->getName(),
Info, Tok.getLocation());
}
// Figure out how many tokens we are into LineToks.
unsigned LineIndex = 0;
if (Tok.is(EndOfStream)) {
LineIndex = LineToks.size() - 2;
} else {
while (LineToks[LineIndex].getLocation() != Tok.getLocation()) {
LineIndex++;
assert(LineIndex < LineToks.size() - 2); // we added two extra tokens
}
}
// If we've run into the poison token we inserted before, or there
// was a parsing error, then claim the entire line.
if (Invalid || Tok.is(EndOfStream)) {
NumLineToksConsumed = LineToks.size() - 2;
} else {
// Otherwise, claim up to the start of the next token.
NumLineToksConsumed = LineIndex;
}
// Finally, restore the old parsing state by consuming all the tokens we
// staged before, implicitly killing off the token-lexer we pushed.
for (unsigned i = 0, e = LineToks.size() - LineIndex - 2; i != e; ++i) {
ConsumeAnyToken();
}
assert(Tok.is(EndOfStream));
ConsumeToken();
// Leave LineToks in its original state.
LineToks.pop_back();
LineToks.pop_back();
return Result;
}
/// Turn a sequence of our tokens back into a string that we can hand
/// to the MC asm parser.
static bool buildMSAsmString(Preprocessor &PP, SourceLocation AsmLoc,
ArrayRef<Token> AsmToks,
SmallVectorImpl<unsigned> &TokOffsets,
SmallString<512> &Asm) {
assert(!AsmToks.empty() && "Didn't expect an empty AsmToks!");
// Is this the start of a new assembly statement?
bool isNewStatement = true;
for (unsigned i = 0, e = AsmToks.size(); i < e; ++i) {
const Token &Tok = AsmToks[i];
// Start each new statement with a newline and a tab.
if (!isNewStatement && (Tok.is(tok::kw_asm) || Tok.isAtStartOfLine())) {
Asm += "\n\t";
isNewStatement = true;
}
// Preserve the existence of leading whitespace except at the
// start of a statement.
if (!isNewStatement && Tok.hasLeadingSpace())
Asm += ' ';
// Remember the offset of this token.
TokOffsets.push_back(Asm.size());
// Don't actually write '__asm' into the assembly stream.
if (Tok.is(tok::kw_asm)) {
// Complain about __asm at the end of the stream.
if (i + 1 == e) {
PP.Diag(AsmLoc, diag::err_asm_empty);
return true;
}
continue;
}
// Append the spelling of the token.
SmallString<32> SpellingBuffer;
bool SpellingInvalid = false;
Asm += PP.getSpelling(Tok, SpellingBuffer, &SpellingInvalid);
assert(!SpellingInvalid && "spelling was invalid after correct parse?");
// We are no longer at the start of a statement.
isNewStatement = false;
}
// Ensure that the buffer is null-terminated.
Asm.push_back('\0');
Asm.pop_back();
assert(TokOffsets.size() == AsmToks.size());
return false;
}
/// ParseMicrosoftAsmStatement. When -fms-extensions/-fasm-blocks is enabled,
/// this routine is called to collect the tokens for an MS asm statement.
///
/// [MS] ms-asm-statement:
/// ms-asm-block
/// ms-asm-block ms-asm-statement
///
/// [MS] ms-asm-block:
/// '__asm' ms-asm-line '\n'
/// '__asm' '{' ms-asm-instruction-block[opt] '}' ';'[opt]
///
/// [MS] ms-asm-instruction-block
/// ms-asm-line
/// ms-asm-line '\n' ms-asm-instruction-block
///
StmtResult Parser::ParseMicrosoftAsmStatement(SourceLocation AsmLoc) {
SourceManager &SrcMgr = PP.getSourceManager();
SourceLocation EndLoc = AsmLoc;
SmallVector<Token, 4> AsmToks;
bool SingleLineMode = true;
unsigned BraceNesting = 0;
unsigned short savedBraceCount = BraceCount;
bool InAsmComment = false;
FileID FID;
unsigned LineNo = 0;
unsigned NumTokensRead = 0;
SmallVector<SourceLocation, 4> LBraceLocs;
bool SkippedStartOfLine = false;
if (Tok.is(tok::l_brace)) {
// Braced inline asm: consume the opening brace.
SingleLineMode = false;
BraceNesting = 1;
EndLoc = ConsumeBrace();
LBraceLocs.push_back(EndLoc);
++NumTokensRead;
} else {
// Single-line inline asm; compute which line it is on.
std::pair<FileID, unsigned> ExpAsmLoc =
SrcMgr.getDecomposedExpansionLoc(EndLoc);
FID = ExpAsmLoc.first;
LineNo = SrcMgr.getLineNumber(FID, ExpAsmLoc.second);
LBraceLocs.push_back(SourceLocation());
}
SourceLocation TokLoc = Tok.getLocation();
do {
// If we hit EOF, we're done, period.
if (isEofOrEom())
break;
if (!InAsmComment && Tok.is(tok::l_brace)) {
// Consume the opening brace.
SkippedStartOfLine = Tok.isAtStartOfLine();
EndLoc = ConsumeBrace();
BraceNesting++;
LBraceLocs.push_back(EndLoc);
TokLoc = Tok.getLocation();
++NumTokensRead;
continue;
} else if (!InAsmComment && Tok.is(tok::semi)) {
// A semicolon in an asm is the start of a comment.
InAsmComment = true;
if (!SingleLineMode) {
// Compute which line the comment is on.
std::pair<FileID, unsigned> ExpSemiLoc =
SrcMgr.getDecomposedExpansionLoc(TokLoc);
FID = ExpSemiLoc.first;
LineNo = SrcMgr.getLineNumber(FID, ExpSemiLoc.second);
}
} else if (SingleLineMode || InAsmComment) {
// If end-of-line is significant, check whether this token is on a
// new line.
std::pair<FileID, unsigned> ExpLoc =
SrcMgr.getDecomposedExpansionLoc(TokLoc);
if (ExpLoc.first != FID ||
SrcMgr.getLineNumber(ExpLoc.first, ExpLoc.second) != LineNo) {
// If this is a single-line __asm, we're done, except if the next
// line begins with an __asm too, in which case we finish a comment
// if needed and then keep processing the next line as a single
// line __asm.
bool isAsm = Tok.is(tok::kw_asm);
if (SingleLineMode && !isAsm)
break;
// We're no longer in a comment.
InAsmComment = false;
if (isAsm) {
// If this is a new __asm {} block we want to process it seperately
// from the single-line __asm statements
if (PP.LookAhead(0).is(tok::l_brace))
break;
LineNo = SrcMgr.getLineNumber(ExpLoc.first, ExpLoc.second);
SkippedStartOfLine = Tok.isAtStartOfLine();
}
} else if (!InAsmComment && Tok.is(tok::r_brace)) {
// In MSVC mode, braces only participate in brace matching and
// separating the asm statements. This is an intentional
// departure from the Apple gcc behavior.
if (!BraceNesting)
break;
}
}
if (!InAsmComment && BraceNesting && Tok.is(tok::r_brace) &&
BraceCount == (savedBraceCount + BraceNesting)) {
// Consume the closing brace.
SkippedStartOfLine = Tok.isAtStartOfLine();
EndLoc = ConsumeBrace();
BraceNesting--;
// Finish if all of the opened braces in the inline asm section were
// consumed.
if (BraceNesting == 0 && !SingleLineMode)
break;
else {
LBraceLocs.pop_back();
TokLoc = Tok.getLocation();
++NumTokensRead;
continue;
}
}
// Consume the next token; make sure we don't modify the brace count etc.
// if we are in a comment.
EndLoc = TokLoc;
if (InAsmComment)
PP.Lex(Tok);
else {
// Set the token as the start of line if we skipped the original start
// of line token in case it was a nested brace.
if (SkippedStartOfLine)
Tok.setFlag(Token::StartOfLine);
AsmToks.push_back(Tok);
ConsumeAnyToken();
}
TokLoc = Tok.getLocation();
++NumTokensRead;
SkippedStartOfLine = false;
} while (1);
if (BraceNesting && BraceCount != savedBraceCount) {
// __asm without closing brace (this can happen at EOF).
for (unsigned i = 0; i < BraceNesting; ++i) {
Diag(Tok, diag::err_expected) << tok::r_brace;
Diag(LBraceLocs.back(), diag::note_matching) << tok::l_brace;
LBraceLocs.pop_back();
}
return StmtError();
} else if (NumTokensRead == 0) {
// Empty __asm.
Diag(Tok, diag::err_expected) << tok::l_brace;
return StmtError();
}
// Okay, prepare to use MC to parse the assembly.
SmallVector<StringRef, 4> ConstraintRefs;
SmallVector<Expr *, 4> Exprs;
SmallVector<StringRef, 4> ClobberRefs;
// We need an actual supported target.
const llvm::Triple &TheTriple = Actions.Context.getTargetInfo().getTriple();
llvm::Triple::ArchType ArchTy = TheTriple.getArch();
const std::string &TT = TheTriple.getTriple();
const llvm::Target *TheTarget = nullptr;
bool UnsupportedArch =
(ArchTy != llvm::Triple::x86 && ArchTy != llvm::Triple::x86_64);
if (UnsupportedArch) {
Diag(AsmLoc, diag::err_msasm_unsupported_arch) << TheTriple.getArchName();
} else {
std::string Error;
TheTarget = llvm::TargetRegistry::lookupTarget(TT, Error);
if (!TheTarget)
Diag(AsmLoc, diag::err_msasm_unable_to_create_target) << Error;
}
assert(!LBraceLocs.empty() && "Should have at least one location here");
// If we don't support assembly, or the assembly is empty, we don't
// need to instantiate the AsmParser, etc.
if (!TheTarget || AsmToks.empty()) {
return Actions.ActOnMSAsmStmt(AsmLoc, LBraceLocs[0], AsmToks, StringRef(),
/*NumOutputs*/ 0, /*NumInputs*/ 0,
ConstraintRefs, ClobberRefs, Exprs, EndLoc);
}
// Expand the tokens into a string buffer.
SmallString<512> AsmString;
SmallVector<unsigned, 8> TokOffsets;
if (buildMSAsmString(PP, AsmLoc, AsmToks, TokOffsets, AsmString))
return StmtError();
TargetOptions TO = Actions.Context.getTargetInfo().getTargetOpts();
std::string FeaturesStr =
llvm::join(TO.Features.begin(), TO.Features.end(), ",");
std::unique_ptr<llvm::MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TT));
std::unique_ptr<llvm::MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, TT));
// Get the instruction descriptor.
std::unique_ptr<llvm::MCInstrInfo> MII(TheTarget->createMCInstrInfo());
std::unique_ptr<llvm::MCObjectFileInfo> MOFI(new llvm::MCObjectFileInfo());
std::unique_ptr<llvm::MCSubtargetInfo> STI(
TheTarget->createMCSubtargetInfo(TT, TO.CPU, FeaturesStr));
llvm::SourceMgr TempSrcMgr;
llvm::MCContext Ctx(MAI.get(), MRI.get(), MOFI.get(), &TempSrcMgr);
MOFI->InitMCObjectFileInfo(TheTriple, llvm::Reloc::Default,
llvm::CodeModel::Default, Ctx);
std::unique_ptr<llvm::MemoryBuffer> Buffer =
llvm::MemoryBuffer::getMemBuffer(AsmString, "<MS inline asm>");
// Tell SrcMgr about this buffer, which is what the parser will pick up.
TempSrcMgr.AddNewSourceBuffer(std::move(Buffer), llvm::SMLoc());
std::unique_ptr<llvm::MCStreamer> Str(createNullStreamer(Ctx));
std::unique_ptr<llvm::MCAsmParser> Parser(
createMCAsmParser(TempSrcMgr, Ctx, *Str.get(), *MAI));
// FIXME: init MCOptions from sanitizer flags here.
llvm::MCTargetOptions MCOptions;
std::unique_ptr<llvm::MCTargetAsmParser> TargetParser(
TheTarget->createMCAsmParser(*STI, *Parser, *MII, MCOptions));
std::unique_ptr<llvm::MCInstPrinter> IP(
TheTarget->createMCInstPrinter(llvm::Triple(TT), 1, *MAI, *MII, *MRI));
// Change to the Intel dialect.
Parser->setAssemblerDialect(1);
Parser->setTargetParser(*TargetParser.get());
Parser->setParsingInlineAsm(true);
TargetParser->setParsingInlineAsm(true);
ClangAsmParserCallback Callback(*this, AsmLoc, AsmString, AsmToks,
TokOffsets);
TargetParser->setSemaCallback(&Callback);
TempSrcMgr.setDiagHandler(ClangAsmParserCallback::DiagHandlerCallback,
&Callback);
unsigned NumOutputs;
unsigned NumInputs;
std::string AsmStringIR;
SmallVector<std::pair<void *, bool>, 4> OpExprs;
SmallVector<std::string, 4> Constraints;
SmallVector<std::string, 4> Clobbers;
if (Parser->parseMSInlineAsm(AsmLoc.getPtrEncoding(), AsmStringIR, NumOutputs,
NumInputs, OpExprs, Constraints, Clobbers,
MII.get(), IP.get(), Callback))
return StmtError();
// Filter out "fpsw". Clang doesn't accept it, and it always lists flags and
// fpsr as clobbers.
auto End = std::remove(Clobbers.begin(), Clobbers.end(), "fpsw");
Clobbers.erase(End, Clobbers.end());
// Build the vector of clobber StringRefs.
ClobberRefs.insert(ClobberRefs.end(), Clobbers.begin(), Clobbers.end());
// Recast the void pointers and build the vector of constraint StringRefs.
unsigned NumExprs = NumOutputs + NumInputs;
ConstraintRefs.resize(NumExprs);
Exprs.resize(NumExprs);
for (unsigned i = 0, e = NumExprs; i != e; ++i) {
Expr *OpExpr = static_cast<Expr *>(OpExprs[i].first);
if (!OpExpr)
return StmtError();
// Need address of variable.
if (OpExprs[i].second)
OpExpr =
Actions.BuildUnaryOp(getCurScope(), AsmLoc, UO_AddrOf, OpExpr).get();
ConstraintRefs[i] = StringRef(Constraints[i]);
Exprs[i] = OpExpr;
}
// FIXME: We should be passing source locations for better diagnostics.
return Actions.ActOnMSAsmStmt(AsmLoc, LBraceLocs[0], AsmToks, AsmStringIR,
NumOutputs, NumInputs, ConstraintRefs,
ClobberRefs, Exprs, EndLoc);
}
/// ParseAsmStatement - Parse a GNU extended asm statement.
/// asm-statement:
/// gnu-asm-statement
/// ms-asm-statement
///
/// [GNU] gnu-asm-statement:
/// 'asm' type-qualifier[opt] '(' asm-argument ')' ';'
///
/// [GNU] asm-argument:
/// asm-string-literal
/// asm-string-literal ':' asm-operands[opt]
/// asm-string-literal ':' asm-operands[opt] ':' asm-operands[opt]
/// asm-string-literal ':' asm-operands[opt] ':' asm-operands[opt]
/// ':' asm-clobbers
///
/// [GNU] asm-clobbers:
/// asm-string-literal
/// asm-clobbers ',' asm-string-literal
///
StmtResult Parser::ParseAsmStatement(bool &msAsm) {
assert(Tok.is(tok::kw_asm) && "Not an asm stmt");
SourceLocation AsmLoc = ConsumeToken();
if (getLangOpts().AsmBlocks && Tok.isNot(tok::l_paren) &&
!isTypeQualifier()) {
msAsm = true;
return ParseMicrosoftAsmStatement(AsmLoc);
}
DeclSpec DS(AttrFactory);
SourceLocation Loc = Tok.getLocation();
ParseTypeQualifierListOpt(DS, AR_VendorAttributesParsed);
// GNU asms accept, but warn, about type-qualifiers other than volatile.
if (DS.getTypeQualifiers() & DeclSpec::TQ_const)
Diag(Loc, diag::w_asm_qualifier_ignored) << "const";
if (DS.getTypeQualifiers() & DeclSpec::TQ_restrict)
Diag(Loc, diag::w_asm_qualifier_ignored) << "restrict";
// FIXME: Once GCC supports _Atomic, check whether it permits it here.
if (DS.getTypeQualifiers() & DeclSpec::TQ_atomic)
Diag(Loc, diag::w_asm_qualifier_ignored) << "_Atomic";
// Remember if this was a volatile asm.
bool isVolatile = DS.getTypeQualifiers() & DeclSpec::TQ_volatile;
if (Tok.isNot(tok::l_paren)) {
Diag(Tok, diag::err_expected_lparen_after) << "asm";
SkipUntil(tok::r_paren, StopAtSemi);
return StmtError();
}
BalancedDelimiterTracker T(*this, tok::l_paren);
T.consumeOpen();
ExprResult AsmString(ParseAsmStringLiteral());
// Check if GNU-style InlineAsm is disabled.
// Error on anything other than empty string.
if (!(getLangOpts().GNUAsm || AsmString.isInvalid())) {
const auto *SL = cast<StringLiteral>(AsmString.get());
if (!SL->getString().trim().empty())
Diag(Loc, diag::err_gnu_inline_asm_disabled);
}
if (AsmString.isInvalid()) {
// Consume up to and including the closing paren.
T.skipToEnd();
return StmtError();
}
SmallVector<IdentifierInfo *, 4> Names;
ExprVector Constraints;
ExprVector Exprs;
ExprVector Clobbers;
if (Tok.is(tok::r_paren)) {
// We have a simple asm expression like 'asm("foo")'.
T.consumeClose();
return Actions.ActOnGCCAsmStmt(AsmLoc, /*isSimple*/ true, isVolatile,
/*NumOutputs*/ 0, /*NumInputs*/ 0, nullptr,
Constraints, Exprs, AsmString.get(),
Clobbers, T.getCloseLocation());
}
// Parse Outputs, if present.
bool AteExtraColon = false;
if (Tok.is(tok::colon) || Tok.is(tok::coloncolon)) {
// In C++ mode, parse "::" like ": :".
AteExtraColon = Tok.is(tok::coloncolon);
ConsumeToken();
if (!AteExtraColon && ParseAsmOperandsOpt(Names, Constraints, Exprs))
return StmtError();
}
unsigned NumOutputs = Names.size();
// Parse Inputs, if present.
if (AteExtraColon || Tok.is(tok::colon) || Tok.is(tok::coloncolon)) {
// In C++ mode, parse "::" like ": :".
if (AteExtraColon)
AteExtraColon = false;
else {
AteExtraColon = Tok.is(tok::coloncolon);
ConsumeToken();
}
if (!AteExtraColon && ParseAsmOperandsOpt(Names, Constraints, Exprs))
return StmtError();
}
assert(Names.size() == Constraints.size() &&
Constraints.size() == Exprs.size() && "Input operand size mismatch!");
unsigned NumInputs = Names.size() - NumOutputs;
// Parse the clobbers, if present.
if (AteExtraColon || Tok.is(tok::colon)) {
if (!AteExtraColon)
ConsumeToken();
// Parse the asm-string list for clobbers if present.
if (Tok.isNot(tok::r_paren)) {
while (1) {
ExprResult Clobber(ParseAsmStringLiteral());
if (Clobber.isInvalid())
break;
Clobbers.push_back(Clobber.get());
if (!TryConsumeToken(tok::comma))
break;
}
}
}
T.consumeClose();
return Actions.ActOnGCCAsmStmt(
AsmLoc, false, isVolatile, NumOutputs, NumInputs, Names.data(),
Constraints, Exprs, AsmString.get(), Clobbers, T.getCloseLocation());
}
/// ParseAsmOperands - Parse the asm-operands production as used by
/// asm-statement, assuming the leading ':' token was eaten.
///
/// [GNU] asm-operands:
/// asm-operand
/// asm-operands ',' asm-operand
///
/// [GNU] asm-operand:
/// asm-string-literal '(' expression ')'
/// '[' identifier ']' asm-string-literal '(' expression ')'
///
//
// FIXME: Avoid unnecessary std::string trashing.
bool Parser::ParseAsmOperandsOpt(SmallVectorImpl<IdentifierInfo *> &Names,
SmallVectorImpl<Expr *> &Constraints,
SmallVectorImpl<Expr *> &Exprs) {
// 'asm-operands' isn't present?
if (!isTokenStringLiteral() && Tok.isNot(tok::l_square))
return false;
while (1) {
// Read the [id] if present.
if (Tok.is(tok::l_square)) {
BalancedDelimiterTracker T(*this, tok::l_square);
T.consumeOpen();
if (Tok.isNot(tok::identifier)) {
Diag(Tok, diag::err_expected) << tok::identifier;
SkipUntil(tok::r_paren, StopAtSemi);
return true;
}
IdentifierInfo *II = Tok.getIdentifierInfo();
ConsumeToken();
Names.push_back(II);
T.consumeClose();
} else
Names.push_back(nullptr);
ExprResult Constraint(ParseAsmStringLiteral());
if (Constraint.isInvalid()) {
SkipUntil(tok::r_paren, StopAtSemi);
return true;
}
Constraints.push_back(Constraint.get());
if (Tok.isNot(tok::l_paren)) {
Diag(Tok, diag::err_expected_lparen_after) << "asm operand";
SkipUntil(tok::r_paren, StopAtSemi);
return true;
}
// Read the parenthesized expression.
BalancedDelimiterTracker T(*this, tok::l_paren);
T.consumeOpen();
ExprResult Res = Actions.CorrectDelayedTyposInExpr(ParseExpression());
T.consumeClose();
if (Res.isInvalid()) {
SkipUntil(tok::r_paren, StopAtSemi);
return true;
}
Exprs.push_back(Res.get());
// Eat the comma and continue parsing if it exists.
if (!TryConsumeToken(tok::comma))
return false;
}
}
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