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//===- SymbolListFile.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 parser/evaluator of the linker script.
// It does not construct an AST but consume linker script directives directly.
// Results are written to Driver or Config object.
//
//===----------------------------------------------------------------------===//
#include "SymbolListFile.h"
#include "Config.h"
#include "ScriptParser.h"
#include "llvm/Support/MemoryBuffer.h"
using namespace llvm;
using namespace llvm::ELF;
using namespace lld;
using namespace lld::elf;
// Parse the --dynamic-list argument. A dynamic list is in the form
//
// { symbol1; symbol2; [...]; symbolN };
//
// Multiple groups can be defined in the same file, and they are merged
// into a single group.
class DynamicListParser final : public ScriptParserBase {
public:
DynamicListParser(StringRef S) : ScriptParserBase(S) {}
void run();
};
void DynamicListParser::run() {
while (!atEOF()) {
expect("{");
while (!Error) {
Config->DynamicList.push_back(next());
expect(";");
if (skip("}"))
break;
}
expect(";");
}
}
void elf::parseDynamicList(MemoryBufferRef MB) {
DynamicListParser(MB.getBuffer()).run();
}
// Parse the --version-script argument. We currently only accept the following
// version script syntax:
//
// { [ global: symbol1; symbol2; [...]; symbolN; ] local: *; };
//
// No wildcards are supported, other than for the local entry. Symbol versioning
// is also not supported.
class VersionScriptParser final : public ScriptParserBase {
public:
VersionScriptParser(StringRef S) : ScriptParserBase(S) {}
void run();
private:
void parseExtern(std::vector<SymbolVersion> *Globals);
void parseVersion(StringRef VerStr);
void parseGlobal(StringRef VerStr);
void parseLocal();
};
size_t elf::defineSymbolVersion(StringRef VerStr) {
// Identifiers start at 2 because 0 and 1 are reserved
// for VER_NDX_LOCAL and VER_NDX_GLOBAL constants.
size_t VersionId = Config->VersionDefinitions.size() + 2;
Config->VersionDefinitions.push_back({VerStr, VersionId});
return VersionId;
}
void VersionScriptParser::parseVersion(StringRef VerStr) {
defineSymbolVersion(VerStr);
if (skip("global:") || peek() != "local:")
parseGlobal(VerStr);
if (skip("local:"))
parseLocal();
expect("}");
// Each version may have a parent version. For example, "Ver2" defined as
// "Ver2 { global: foo; local: *; } Ver1;" has "Ver1" as a parent. This
// version hierarchy is, probably against your instinct, purely for human; the
// runtime doesn't care about them at all. In LLD, we simply skip the token.
if (!VerStr.empty() && peek() != ";")
next();
expect(";");
}
void VersionScriptParser::parseLocal() {
Config->DefaultSymbolVersion = VER_NDX_LOCAL;
expect("*");
expect(";");
}
void VersionScriptParser::parseExtern(std::vector<SymbolVersion> *Globals) {
expect("C++");
expect("{");
for (;;) {
if (peek() == "}" || Error)
break;
Globals->push_back({next(), true});
expect(";");
}
expect("}");
expect(";");
}
void VersionScriptParser::parseGlobal(StringRef VerStr) {
std::vector<SymbolVersion> *Globals;
if (VerStr.empty())
Globals = &Config->VersionScriptGlobals;
else
Globals = &Config->VersionDefinitions.back().Globals;
for (;;) {
if (skip("extern"))
parseExtern(Globals);
StringRef Cur = peek();
if (Cur == "}" || Cur == "local:" || Error)
return;
next();
Globals->push_back({Cur, false});
expect(";");
}
}
void VersionScriptParser::run() {
StringRef Msg = "anonymous version definition is used in "
"combination with other version definitions";
if (skip("{")) {
parseVersion("");
if (!atEOF())
setError(Msg);
return;
}
while (!atEOF() && !Error) {
StringRef VerStr = next();
if (VerStr == "{") {
setError(Msg);
return;
}
expect("{");
parseVersion(VerStr);
}
}
void elf::parseVersionScript(MemoryBufferRef MB) {
VersionScriptParser(MB.getBuffer()).run();
}
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