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llvm-project/llvm/lib/MC/MCParser/AsmLexer.cpp

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//===- AsmLexer.cpp - Lexer for Assembly Files ----------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This class implements the lexer for assembly files.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCParser/AsmLexer.h"
#include "llvm/Support/SMLoc.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/MC/MCAsmInfo.h"
#include <cerrno>
#include <cstdio>
#include <cstdlib>
using namespace llvm;
AsmLexer::AsmLexer(const MCAsmInfo &_MAI) : MAI(_MAI) {
CurBuf = NULL;
CurPtr = NULL;
}
AsmLexer::~AsmLexer() {
}
void AsmLexer::setBuffer(const MemoryBuffer *buf, const char *ptr) {
CurBuf = buf;
if (ptr)
CurPtr = ptr;
else
CurPtr = CurBuf->getBufferStart();
TokStart = 0;
}
/// ReturnError - Set the error to the specified string at the specified
/// location. This is defined to always return AsmToken::Error.
AsmToken AsmLexer::ReturnError(const char *Loc, const std::string &Msg) {
SetError(SMLoc::getFromPointer(Loc), Msg);
return AsmToken(AsmToken::Error, StringRef(Loc, 0));
}
int AsmLexer::getNextChar() {
char CurChar = *CurPtr++;
switch (CurChar) {
default:
return (unsigned char)CurChar;
case 0:
// A nul character in the stream is either the end of the current buffer or
// a random nul in the file. Disambiguate that here.
if (CurPtr-1 != CurBuf->getBufferEnd())
return 0; // Just whitespace.
// Otherwise, return end of file.
--CurPtr; // Another call to lex will return EOF again.
return EOF;
}
}
/// LexFloatLiteral: [0-9]*[.][0-9]*([eE][+-]?[0-9]*)?
///
/// The leading integral digit sequence and dot should have already been
/// consumed, some or all of the fractional digit sequence *can* have been
/// consumed.
AsmToken AsmLexer::LexFloatLiteral() {
// Skip the fractional digit sequence.
while (isdigit(*CurPtr))
++CurPtr;
// Check for exponent; we intentionally accept a slighlty wider set of
// literals here and rely on the upstream client to reject invalid ones (e.g.,
// "1e+").
if (*CurPtr == 'e' || *CurPtr == 'E') {
++CurPtr;
if (*CurPtr == '-' || *CurPtr == '+')
++CurPtr;
while (isdigit(*CurPtr))
++CurPtr;
}
return AsmToken(AsmToken::Real,
StringRef(TokStart, CurPtr - TokStart));
}
/// LexIdentifier: [a-zA-Z_.][a-zA-Z0-9_$.@]*
static bool IsIdentifierChar(char c) {
return isalnum(c) || c == '_' || c == '$' || c == '.' || c == '@';
}
AsmToken AsmLexer::LexIdentifier() {
// Check for floating point literals.
if (CurPtr[-1] == '.' && isdigit(*CurPtr)) {
// Disambiguate a .1243foo identifier from a floating literal.
while (isdigit(*CurPtr))
++CurPtr;
if (*CurPtr == 'e' || *CurPtr == 'E' || !IsIdentifierChar(*CurPtr))
return LexFloatLiteral();
}
while (IsIdentifierChar(*CurPtr))
++CurPtr;
// Handle . as a special case.
if (CurPtr == TokStart+1 && TokStart[0] == '.')
return AsmToken(AsmToken::Dot, StringRef(TokStart, 1));
return AsmToken(AsmToken::Identifier, StringRef(TokStart, CurPtr - TokStart));
}
/// LexSlash: Slash: /
/// C-Style Comment: /* ... */
AsmToken AsmLexer::LexSlash() {
switch (*CurPtr) {
case '*': break; // C style comment.
case '/': return ++CurPtr, LexLineComment();
default: return AsmToken(AsmToken::Slash, StringRef(CurPtr, 1));
}
// C Style comment.
++CurPtr; // skip the star.
while (1) {
int CurChar = getNextChar();
switch (CurChar) {
case EOF:
return ReturnError(TokStart, "unterminated comment");
case '*':
// End of the comment?
if (CurPtr[0] != '/') break;
++CurPtr; // End the */.
return LexToken();
}
}
}
/// LexLineComment: Comment: #[^\n]*
/// : //[^\n]*
AsmToken AsmLexer::LexLineComment() {
// FIXME: This is broken if we happen to a comment at the end of a file, which
// was .included, and which doesn't end with a newline.
int CurChar = getNextChar();
while (CurChar != '\n' && CurChar != '\n' && CurChar != EOF)
CurChar = getNextChar();
if (CurChar == EOF)
return AsmToken(AsmToken::Eof, StringRef(CurPtr, 0));
return AsmToken(AsmToken::EndOfStatement, StringRef(CurPtr, 0));
}
static void SkipIgnoredIntegerSuffix(const char *&CurPtr) {
if (CurPtr[0] == 'L' && CurPtr[1] == 'L')
CurPtr += 2;
if (CurPtr[0] == 'U' && CurPtr[1] == 'L' && CurPtr[2] == 'L')
CurPtr += 3;
}
/// LexDigit: First character is [0-9].
/// Local Label: [0-9][:]
/// Forward/Backward Label: [0-9][fb]
/// Binary integer: 0b[01]+
/// Octal integer: 0[0-7]+
/// Hex integer: 0x[0-9a-fA-F]+
/// Decimal integer: [1-9][0-9]*
AsmToken AsmLexer::LexDigit() {
// Decimal integer: [1-9][0-9]*
if (CurPtr[-1] != '0' || CurPtr[0] == '.') {
while (isdigit(*CurPtr))
++CurPtr;
// Check for floating point literals.
if (*CurPtr == '.' || *CurPtr == 'e') {
++CurPtr;
return LexFloatLiteral();
}
StringRef Result(TokStart, CurPtr - TokStart);
long long Value;
if (Result.getAsInteger(10, Value)) {
// We have to handle minint_as_a_positive_value specially, because
// - minint_as_a_positive_value = minint and it is valid.
if (Result == "9223372036854775808")
Value = -9223372036854775808ULL;
else
return ReturnError(TokStart, "Invalid decimal number");
}
// The darwin/x86 (and x86-64) assembler accepts and ignores ULL and LL
// suffixes on integer literals.
SkipIgnoredIntegerSuffix(CurPtr);
return AsmToken(AsmToken::Integer, Result, Value);
}
if (*CurPtr == 'b') {
++CurPtr;
// See if we actually have "0b" as part of something like "jmp 0b\n"
if (!isdigit(CurPtr[0])) {
--CurPtr;
StringRef Result(TokStart, CurPtr - TokStart);
return AsmToken(AsmToken::Integer, Result, 0);
}
const char *NumStart = CurPtr;
while (CurPtr[0] == '0' || CurPtr[0] == '1')
++CurPtr;
// Requires at least one binary digit.
if (CurPtr == NumStart)
return ReturnError(TokStart, "Invalid binary number");
StringRef Result(TokStart, CurPtr - TokStart);
long long Value;
if (Result.substr(2).getAsInteger(2, Value))
return ReturnError(TokStart, "Invalid binary number");
// The darwin/x86 (and x86-64) assembler accepts and ignores ULL and LL
// suffixes on integer literals.
SkipIgnoredIntegerSuffix(CurPtr);
return AsmToken(AsmToken::Integer, Result, Value);
}
if (*CurPtr == 'x') {
++CurPtr;
const char *NumStart = CurPtr;
while (isxdigit(CurPtr[0]))
++CurPtr;
// Requires at least one hex digit.
if (CurPtr == NumStart)
return ReturnError(CurPtr-2, "Invalid hexadecimal number");
unsigned long long Result;
if (StringRef(TokStart, CurPtr - TokStart).getAsInteger(0, Result))
return ReturnError(TokStart, "Invalid hexadecimal number");
// The darwin/x86 (and x86-64) assembler accepts and ignores ULL and LL
// suffixes on integer literals.
SkipIgnoredIntegerSuffix(CurPtr);
return AsmToken(AsmToken::Integer, StringRef(TokStart, CurPtr - TokStart),
(int64_t)Result);
}
// Must be an octal number, it starts with 0.
while (*CurPtr >= '0' && *CurPtr <= '7')
++CurPtr;
StringRef Result(TokStart, CurPtr - TokStart);
long long Value;
if (Result.getAsInteger(8, Value))
return ReturnError(TokStart, "Invalid octal number");
// The darwin/x86 (and x86-64) assembler accepts and ignores ULL and LL
// suffixes on integer literals.
SkipIgnoredIntegerSuffix(CurPtr);
return AsmToken(AsmToken::Integer, Result, Value);
}
/// LexQuote: String: "..."
AsmToken AsmLexer::LexQuote() {
int CurChar = getNextChar();
// TODO: does gas allow multiline string constants?
while (CurChar != '"') {
if (CurChar == '\\') {
// Allow \", etc.
CurChar = getNextChar();
}
if (CurChar == EOF)
return ReturnError(TokStart, "unterminated string constant");
CurChar = getNextChar();
}
return AsmToken(AsmToken::String, StringRef(TokStart, CurPtr - TokStart));
}
StringRef AsmLexer::LexUntilEndOfStatement() {
TokStart = CurPtr;
while (!isAtStartOfComment(*CurPtr) && // Start of line comment.
*CurPtr != ';' && // End of statement marker.
*CurPtr != '\n' &&
*CurPtr != '\r' &&
(*CurPtr != 0 || CurPtr != CurBuf->getBufferEnd())) {
++CurPtr;
}
return StringRef(TokStart, CurPtr-TokStart);
}
bool AsmLexer::isAtStartOfComment(char Char) {
// FIXME: This won't work for multi-character comment indicators like "//".
return Char == *MAI.getCommentString();
}
AsmToken AsmLexer::LexToken() {
TokStart = CurPtr;
// This always consumes at least one character.
int CurChar = getNextChar();
if (isAtStartOfComment(CurChar))
return LexLineComment();
switch (CurChar) {
default:
// Handle identifier: [a-zA-Z_.][a-zA-Z0-9_$.@]*
if (isalpha(CurChar) || CurChar == '_' || CurChar == '.')
return LexIdentifier();
// Unknown character, emit an error.
return ReturnError(TokStart, "invalid character in input");
case EOF: return AsmToken(AsmToken::Eof, StringRef(TokStart, 0));
case 0:
case ' ':
case '\t':
// Ignore whitespace.
return LexToken();
case '\n': // FALL THROUGH.
case '\r': // FALL THROUGH.
case ';': return AsmToken(AsmToken::EndOfStatement, StringRef(TokStart, 1));
case ':': return AsmToken(AsmToken::Colon, StringRef(TokStart, 1));
case '+': return AsmToken(AsmToken::Plus, StringRef(TokStart, 1));
case '-': return AsmToken(AsmToken::Minus, StringRef(TokStart, 1));
case '~': return AsmToken(AsmToken::Tilde, StringRef(TokStart, 1));
case '(': return AsmToken(AsmToken::LParen, StringRef(TokStart, 1));
case ')': return AsmToken(AsmToken::RParen, StringRef(TokStart, 1));
case '[': return AsmToken(AsmToken::LBrac, StringRef(TokStart, 1));
case ']': return AsmToken(AsmToken::RBrac, StringRef(TokStart, 1));
case '{': return AsmToken(AsmToken::LCurly, StringRef(TokStart, 1));
case '}': return AsmToken(AsmToken::RCurly, StringRef(TokStart, 1));
case '*': return AsmToken(AsmToken::Star, StringRef(TokStart, 1));
case ',': return AsmToken(AsmToken::Comma, StringRef(TokStart, 1));
case '$': return AsmToken(AsmToken::Dollar, StringRef(TokStart, 1));
case '@': return AsmToken(AsmToken::At, StringRef(TokStart, 1));
case '=':
if (*CurPtr == '=')
return ++CurPtr, AsmToken(AsmToken::EqualEqual, StringRef(TokStart, 2));
return AsmToken(AsmToken::Equal, StringRef(TokStart, 1));
case '|':
if (*CurPtr == '|')
return ++CurPtr, AsmToken(AsmToken::PipePipe, StringRef(TokStart, 2));
return AsmToken(AsmToken::Pipe, StringRef(TokStart, 1));
case '^': return AsmToken(AsmToken::Caret, StringRef(TokStart, 1));
case '&':
if (*CurPtr == '&')
return ++CurPtr, AsmToken(AsmToken::AmpAmp, StringRef(TokStart, 2));
return AsmToken(AsmToken::Amp, StringRef(TokStart, 1));
case '!':
if (*CurPtr == '=')
return ++CurPtr, AsmToken(AsmToken::ExclaimEqual, StringRef(TokStart, 2));
return AsmToken(AsmToken::Exclaim, StringRef(TokStart, 1));
case '%': return AsmToken(AsmToken::Percent, StringRef(TokStart, 1));
case '/': return LexSlash();
case '#': return AsmToken(AsmToken::Hash, StringRef(TokStart, 1));
case '"': return LexQuote();
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
return LexDigit();
case '<':
switch (*CurPtr) {
case '<': return ++CurPtr, AsmToken(AsmToken::LessLess,
StringRef(TokStart, 2));
case '=': return ++CurPtr, AsmToken(AsmToken::LessEqual,
StringRef(TokStart, 2));
case '>': return ++CurPtr, AsmToken(AsmToken::LessGreater,
StringRef(TokStart, 2));
default: return AsmToken(AsmToken::Less, StringRef(TokStart, 1));
}
case '>':
switch (*CurPtr) {
case '>': return ++CurPtr, AsmToken(AsmToken::GreaterGreater,
StringRef(TokStart, 2));
case '=': return ++CurPtr, AsmToken(AsmToken::GreaterEqual,
StringRef(TokStart, 2));
default: return AsmToken(AsmToken::Greater, StringRef(TokStart, 1));
}
// TODO: Quoted identifiers (objc methods etc)
// local labels: [0-9][:]
// Forward/backward labels: [0-9][fb]
// Integers, fp constants, character constants.
}
}
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