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//===- ScriptParser.cpp ---------------------------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the base parser class for linker script and dynamic
// list.
//
//===----------------------------------------------------------------------===//
#include "ScriptParser.h"
#include "Error.h"
#include "llvm/ADT/Twine.h"
using namespace llvm;
using namespace lld;
using namespace lld::elf;
// Returns a whole line containing the current token.
StringRef ScriptParserBase::getLine() {
StringRef S = getCurrentMB().getBuffer();
StringRef Tok = Tokens[Pos - 1];
size_t Pos = S.rfind('\n', Tok.data() - S.data());
if (Pos != StringRef::npos)
S = S.substr(Pos + 1);
return S.substr(0, S.find_first_of("\r\n"));
}
// Returns 1-based line number of the current token.
size_t ScriptParserBase::getLineNumber() {
StringRef S = getCurrentMB().getBuffer();
StringRef Tok = Tokens[Pos - 1];
return S.substr(0, Tok.data() - S.data()).count('\n') + 1;
}
// Returns 0-based column number of the current token.
size_t ScriptParserBase::getColumnNumber() {
StringRef Tok = Tokens[Pos - 1];
return Tok.data() - getLine().data();
}
std::string ScriptParserBase::getCurrentLocation() {
std::string Filename = getCurrentMB().getBufferIdentifier();
if (!Pos)
return Filename;
return (Filename + ":" + Twine(getLineNumber())).str();
}
ScriptParserBase::ScriptParserBase(MemoryBufferRef MB) { tokenize(MB); }
// We don't want to record cascading errors. Keep only the first one.
void ScriptParserBase::setError(const Twine &Msg) {
if (Error)
return;
Error = true;
if (!Pos) {
error(getCurrentLocation() + ": " + Msg);
return;
}
std::string S = getCurrentLocation() + ": ";
error(S + Msg);
error(S + getLine());
error(S + std::string(getColumnNumber(), ' ') + "^");
}
// Split S into linker script tokens.
void ScriptParserBase::tokenize(MemoryBufferRef MB) {
std::vector<StringRef> Vec;
MBs.push_back(MB);
StringRef S = MB.getBuffer();
StringRef Begin = S;
for (;;) {
S = skipSpace(S);
if (S.empty())
break;
// Quoted token. Note that double-quote characters are parts of a token
// because, in a glob match context, only unquoted tokens are interpreted
// as glob patterns. Double-quoted tokens are literal patterns in that
// context.
if (S.startswith("\"")) {
size_t E = S.find("\"", 1);
if (E == StringRef::npos) {
StringRef Filename = MB.getBufferIdentifier();
size_t Lineno = Begin.substr(0, S.data() - Begin.data()).count('\n');
error(Filename + ":" + Twine(Lineno + 1) + ": unclosed quote");
return;
}
Vec.push_back(S.take_front(E + 1));
S = S.substr(E + 1);
continue;
}
// Unquoted token. This is more relaxed than tokens in C-like language,
// so that you can write "file-name.cpp" as one bare token, for example.
size_t Pos = S.find_first_not_of(
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
"0123456789_.$/\\~=+[]*?-:!<>^");
// A character that cannot start a word (which is usually a
// punctuation) forms a single character token.
if (Pos == 0)
Pos = 1;
Vec.push_back(S.substr(0, Pos));
S = S.substr(Pos);
}
Tokens.insert(Tokens.begin() + Pos, Vec.begin(), Vec.end());
}
// Skip leading whitespace characters or comments.
StringRef ScriptParserBase::skipSpace(StringRef S) {
for (;;) {
if (S.startswith("/*")) {
size_t E = S.find("*/", 2);
if (E == StringRef::npos) {
error("unclosed comment in a linker script");
return "";
}
S = S.substr(E + 2);
continue;
}
if (S.startswith("#")) {
size_t E = S.find('\n', 1);
if (E == StringRef::npos)
E = S.size() - 1;
S = S.substr(E + 1);
continue;
}
size_t Size = S.size();
S = S.ltrim();
if (S.size() == Size)
return S;
}
}
// An erroneous token is handled as if it were the last token before EOF.
bool ScriptParserBase::atEOF() { return Error || Tokens.size() == Pos; }
StringRef ScriptParserBase::next() {
if (Error)
return "";
if (atEOF()) {
setError("unexpected EOF");
return "";
}
return Tokens[Pos++];
}
StringRef ScriptParserBase::peek() {
StringRef Tok = next();
if (Error)
return "";
--Pos;
return Tok;
}
bool ScriptParserBase::consume(StringRef Tok) {
if (peek() == Tok) {
skip();
return true;
}
return false;
}
void ScriptParserBase::skip() { (void)next(); }
void ScriptParserBase::expect(StringRef Expect) {
if (Error)
return;
StringRef Tok = next();
if (Tok != Expect)
setError(Expect + " expected, but got " + Tok);
}
// Returns true if S encloses T.
static bool encloses(StringRef S, StringRef T) {
return S.bytes_begin() <= T.bytes_begin() && T.bytes_end() <= S.bytes_end();
}
MemoryBufferRef ScriptParserBase::getCurrentMB() {
// Find input buffer containing the current token.
assert(!MBs.empty());
if (!Pos)
return MBs[0];
for (MemoryBufferRef MB : MBs)
if (encloses(MB.getBuffer(), Tokens[Pos - 1]))
return MB;
llvm_unreachable("getCurrentMB: failed to find a token");
}
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