//===- 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 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"); }