llvm-project/lld/lib/ReaderWriter/LinkerScript.cpp

290 lines
7.9 KiB
C++

//===- ReaderWriter/LinkerScript.cpp --------------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief Linker script parser.
///
//===----------------------------------------------------------------------===//
#include "lld/ReaderWriter/LinkerScript.h"
namespace lld {
namespace script {
void Token::dump(raw_ostream &os) const {
switch (_kind) {
#define CASE(name) \
case Token::name: \
os << #name ": "; \
break;
CASE(eof)
CASE(identifier)
CASE(kw_as_needed)
CASE(kw_entry)
CASE(kw_group)
CASE(kw_output_format)
CASE(l_paren)
CASE(r_paren)
CASE(unknown)
#undef CASE
}
os << _range << "\n";
}
bool Lexer::canStartName(char c) const {
switch (c) {
case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
case 'V': case 'W': case 'X': case 'Y': case 'Z':
case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
case 'v': case 'w': case 'x': case 'y': case 'z':
case '_': case '.': case '$': case '/': case '\\':
return true;
default:
return false;
}
}
bool Lexer::canContinueName(char c) const {
switch (c) {
case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
case 'V': case 'W': case 'X': case 'Y': case 'Z':
case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
case 'v': case 'w': case 'x': case 'y': case 'z':
case '0': case '1': case '2': case '3': case '4': case '5': case '6':
case '7': case '8': case '9':
case '_': case '.': case '$': case '/': case '\\': case '~': case '=':
case '+': case ',': case '[': case ']': case '*': case '?': case '-':
return true;
default:
return false;
}
}
void Lexer::lex(Token &tok) {
skipWhitespace();
if (_buffer.empty()) {
tok = Token(_buffer, Token::eof);
return;
}
switch (_buffer[0]) {
case 0:
tok = Token(_buffer.substr(0, 1), Token::eof);
_buffer = _buffer.drop_front();
return;
case '(':
tok = Token(_buffer.substr(0, 1), Token::l_paren);
_buffer = _buffer.drop_front();
return;
case ')':
tok = Token(_buffer.substr(0, 1), Token::r_paren);
_buffer = _buffer.drop_front();
return;
default:
/// keyword or identifer.
if (!canStartName(_buffer[0]))
break;
auto endIter =
std::find_if(_buffer.begin() + 1, _buffer.end(), [=](char c) {
return !canContinueName(c);
});
StringRef::size_type end =
endIter == _buffer.end() ? StringRef::npos
: std::distance(_buffer.begin(), endIter);
if (end == StringRef::npos || end == 0)
break;
StringRef word = _buffer.substr(0, end);
Token::Kind kind = llvm::StringSwitch<Token::Kind>(word)
.Case("OUTPUT_FORMAT", Token::kw_output_format)
.Case("GROUP", Token::kw_group)
.Case("AS_NEEDED", Token::kw_as_needed)
.Case("ENTRY", Token::kw_entry)
.Default(Token::identifier);
tok = Token(word, kind);
_buffer = _buffer.drop_front(end);
return;
}
tok = Token(_buffer.substr(0, 1), Token::unknown);
_buffer = _buffer.drop_front();
}
void Lexer::skipWhitespace() {
while (true) {
if (_buffer.empty())
return;
switch (_buffer[0]) {
case ' ':
case '\r':
case '\n':
case '\t':
_buffer = _buffer.drop_front();
break;
// Potential comment.
case '/':
if (_buffer.size() >= 2 && _buffer[1] == '*') {
// Skip starting /*
_buffer = _buffer.drop_front(2);
// If the next char is also a /, it's not the end.
if (!_buffer.empty() && _buffer[0] == '/')
_buffer = _buffer.drop_front();
// Scan for /'s. We're done if it is preceded by a *.
while (true) {
if (_buffer.empty())
break;
_buffer = _buffer.drop_front();
if (_buffer.data()[-1] == '/' && _buffer.data()[-2] == '*')
break;
}
} else
return;
break;
default:
return;
}
}
}
LinkerScript *Parser::parse() {
// Get the first token.
_lex.lex(_tok);
// Parse top level commands.
while (true) {
switch (_tok._kind) {
case Token::eof:
return &_script;
case Token::kw_output_format: {
auto outputFormat = parseOutputFormat();
if (!outputFormat)
return nullptr;
_script._commands.push_back(outputFormat);
break;
}
case Token::kw_group: {
auto group = parseGroup();
if (!group)
return nullptr;
_script._commands.push_back(group);
break;
}
case Token::kw_as_needed:
// Not allowed at top level.
return nullptr;
case Token::kw_entry: {
Entry *entry = parseEntry();
if (!entry)
return nullptr;
_script._commands.push_back(entry);
break;
}
default:
// Unexpected.
return nullptr;
}
}
return nullptr;
}
// Parse OUTPUT_FORMAT(ident)
OutputFormat *Parser::parseOutputFormat() {
assert(_tok._kind == Token::kw_output_format && "Expected OUTPUT_FORMAT!");
consumeToken();
if (!expectAndConsume(Token::l_paren, "expected ("))
return nullptr;
if (_tok._kind != Token::identifier) {
error(_tok, "Expected identifier in OUTPUT_FORMAT.");
return nullptr;
}
auto ret = new (_alloc) OutputFormat(_tok._range);
consumeToken();
if (!expectAndConsume(Token::r_paren, "expected )"))
return nullptr;
return ret;
}
// Parse GROUP(file ...)
Group *Parser::parseGroup() {
assert(_tok._kind == Token::kw_group && "Expected GROUP!");
consumeToken();
if (!expectAndConsume(Token::l_paren, "expected ("))
return nullptr;
std::vector<Path> paths;
while (_tok._kind == Token::identifier || _tok._kind == Token::kw_as_needed) {
switch (_tok._kind) {
case Token::identifier:
paths.push_back(Path(_tok._range));
consumeToken();
break;
case Token::kw_as_needed:
if (!parseAsNeeded(paths))
return nullptr;
break;
default:
llvm_unreachable("Invalid token.");
}
}
auto ret = new (_alloc) Group(paths);
if (!expectAndConsume(Token::r_paren, "expected )"))
return nullptr;
return ret;
}
// Parse AS_NEEDED(file ...)
bool Parser::parseAsNeeded(std::vector<Path> &paths) {
assert(_tok._kind == Token::kw_as_needed && "Expected AS_NEEDED!");
consumeToken();
if (!expectAndConsume(Token::l_paren, "expected ("))
return false;
while (_tok._kind == Token::identifier) {
paths.push_back(Path(_tok._range, true));
consumeToken();
}
if (!expectAndConsume(Token::r_paren, "expected )"))
return false;
return true;
}
// Parse ENTRY(ident)
Entry *Parser::parseEntry() {
assert(_tok._kind == Token::kw_entry && "Expected ENTRY!");
consumeToken();
if (!expectAndConsume(Token::l_paren, "expected ("))
return nullptr;
if (_tok._kind != Token::identifier) {
error(_tok, "expected identifier in ENTRY");
return nullptr;
}
StringRef entryName(_tok._range);
consumeToken();
if (!expectAndConsume(Token::r_paren, "expected )"))
return nullptr;
return new (_alloc) Entry(entryName);
}
} // end namespace script
} // end namespace lld