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llvm-project/clang/lib/Parse/ParseStmtAsm.cpp
Ehsan Akhgari 2f93b448a8 clang-cl: Merge adjacent single-line __asm blocks 
Summary:
This patch extends the __asm parser to make it keep parsing input tokens
as inline assembly if a single-line __asm line is followed by another line
starting with __asm too.  It also makes sure that we correctly keep
matching braces in such situations by separating the notions of how many
braces we are matching and whether we are in single-line asm block mode.

Reviewers: rnk

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D4598

llvm-svn: 213916
2014-07-25 02:27:14 +00:00

773 lines
27 KiB
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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/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/MCRegisterInfo.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCTargetAsmParser.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;
}
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]);
}
}
void handleDiagnostic(const llvm::SMDiagnostic &D) {
// 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::SourceMgr &LSM = *D.getSourceMgr();
const llvm::MemoryBuffer *LBuf =
LSM.getMemoryBuffer(LSM.FindBufferContainingLoc(D.getLoc()));
unsigned Offset = D.getLoc().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);
}
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.begin(), LineToks.size(),
/*disable macros*/ true,
/*owns tokens*/ false);
// 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, ParsedType(), /*EnteringContext=*/false);
}
// Require an identifier here.
SourceLocation TemplateKWLoc;
UnqualifiedId Id;
bool Invalid =
ParseUnqualifiedId(SS,
/*EnteringContext=*/false,
/*AllowDestructorName=*/false,
/*AllowConstructorName=*/false,
/*ObjectType=*/ParsedType(), TemplateKWLoc, Id);
// 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();
// Perform the lookup.
return Actions.LookupInlineAsmIdentifier(SS, TemplateKWLoc, Id, Info,
IsUnevaluatedContext);
}
/// 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) {
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();
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, "", ""));
llvm::SourceMgr TempSrcMgr;
llvm::MCContext Ctx(MAI.get(), MRI.get(), MOFI.get(), &TempSrcMgr);
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(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(1, *MAI, *MII, *MRI, *STI));
// 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());
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(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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