156 lines
3.6 KiB
C++
156 lines
3.6 KiB
C++
//===- LinkerScript.cpp ---------------------------------------------------===//
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//
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// The LLVM Linker
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains the parser/evaluator of the linker script.
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// It does not construct an AST but consume linker script directives directly.
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// Results are written to Symtab or Config object.
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//
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//===----------------------------------------------------------------------===//
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#include "Config.h"
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#include "Driver.h"
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#include "SymbolTable.h"
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#include "llvm/Support/FileSystem.h"
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#include "llvm/Support/MemoryBuffer.h"
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using namespace llvm;
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using namespace lld;
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using namespace lld::elf2;
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namespace {
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class LinkerScript {
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public:
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LinkerScript(StringRef S) : Tokens(tokenize(S)) {}
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void run();
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private:
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static std::vector<StringRef> tokenize(StringRef S);
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static StringRef skipSpace(StringRef S);
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StringRef next();
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bool atEOF() { return Tokens.size() == Pos; }
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void expect(StringRef Expect);
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void readAsNeeded();
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void readGroup();
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void readOutputFormat();
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std::vector<StringRef> Tokens;
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size_t Pos = 0;
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};
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}
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void LinkerScript::run() {
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while (!atEOF()) {
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StringRef Tok = next();
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if (Tok == "GROUP") {
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readGroup();
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} else if (Tok == "OUTPUT_FORMAT") {
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readOutputFormat();
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} else {
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error("unknown directive: " + Tok);
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}
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}
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}
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// Split S into linker script tokens.
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std::vector<StringRef> LinkerScript::tokenize(StringRef S) {
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std::vector<StringRef> Ret;
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for (;;) {
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S = skipSpace(S);
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if (S.empty())
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return Ret;
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// Quoted token
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if (S.startswith("\"")) {
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size_t E = S.find("\"", 1);
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if (E == StringRef::npos)
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error("unclosed quote");
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Ret.push_back(S.substr(1, E));
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S = S.substr(E + 1);
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continue;
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}
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// Unquoted token
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size_t Pos = S.find_first_not_of(
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
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"0123456789_.$/\\~=+[]*?-:");
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// A character that cannot start a word (which is usually a
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// punctuation) forms a single character token.
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if (Pos == 0)
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Pos = 1;
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Ret.push_back(S.substr(0, Pos));
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S = S.substr(Pos);
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}
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}
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// Skip leading whitespace characters or /**/-style comments.
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StringRef LinkerScript::skipSpace(StringRef S) {
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for (;;) {
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if (S.startswith("/*")) {
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size_t E = S.find("*/", 2);
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if (E == StringRef::npos)
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error("unclosed comment in a linker script");
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S = S.substr(E + 2);
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continue;
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}
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size_t Size = S.size();
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S = S.ltrim();
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if (S.size() == Size)
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return S;
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}
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}
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StringRef LinkerScript::next() {
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if (Pos == Tokens.size())
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error("unexpected EOF");
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return Tokens[Pos++];
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}
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void LinkerScript::expect(StringRef Expect) {
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StringRef Tok = next();
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if (Tok != Expect)
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error(Expect + " expected, but got " + Tok);
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}
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void LinkerScript::readAsNeeded() {
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expect("(");
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for (;;) {
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StringRef Tok = next();
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if (Tok == ")")
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return;
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Driver->addFile(Tok);
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}
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}
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void LinkerScript::readGroup() {
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expect("(");
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for (;;) {
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StringRef Tok = next();
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if (Tok == ")")
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return;
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if (Tok == "AS_NEEDED") {
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readAsNeeded();
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continue;
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}
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Driver->addFile(Tok);
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}
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}
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void LinkerScript::readOutputFormat() {
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// Error checking only for now.
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expect("(");
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next();
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expect(")");
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}
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// Entry point. The other functions or classes are private to this file.
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void lld::elf2::readLinkerScript(MemoryBufferRef MB) {
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LinkerScript(MB.getBuffer()).run();
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}
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