forked from OSchip/llvm-project
418 lines
13 KiB
C++
418 lines
13 KiB
C++
//===- SymbolTable.cpp ----------------------------------------------------===//
|
|
//
|
|
// The LLVM Linker
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "Config.h"
|
|
#include "Driver.h"
|
|
#include "Error.h"
|
|
#include "SymbolTable.h"
|
|
#include "Symbols.h"
|
|
#include "llvm/ADT/STLExtras.h"
|
|
#include "llvm/LTO/LTOCodeGenerator.h"
|
|
#include "llvm/Support/Debug.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
#include <utility>
|
|
|
|
using namespace llvm;
|
|
|
|
namespace lld {
|
|
namespace coff {
|
|
|
|
SymbolTable::SymbolTable() {
|
|
addSymbol(new (Alloc) DefinedAbsolute("__ImageBase", Config->ImageBase));
|
|
}
|
|
|
|
void SymbolTable::addFile(std::unique_ptr<InputFile> FileP) {
|
|
InputFile *File = FileP.get();
|
|
Files.push_back(std::move(FileP));
|
|
if (auto *F = dyn_cast<ArchiveFile>(File)) {
|
|
ArchiveQueue.push_back(F);
|
|
return;
|
|
}
|
|
ObjectQueue.push_back(File);
|
|
if (auto *F = dyn_cast<ObjectFile>(File)) {
|
|
ObjectFiles.push_back(F);
|
|
} else if (auto *F = dyn_cast<BitcodeFile>(File)) {
|
|
BitcodeFiles.push_back(F);
|
|
} else {
|
|
ImportFiles.push_back(cast<ImportFile>(File));
|
|
}
|
|
}
|
|
|
|
std::error_code SymbolTable::run() {
|
|
while (!ArchiveQueue.empty() || !ObjectQueue.empty()) {
|
|
if (auto EC = readArchives())
|
|
return EC;
|
|
if (auto EC = readObjects())
|
|
return EC;
|
|
++Version;
|
|
}
|
|
return std::error_code();
|
|
}
|
|
|
|
std::error_code SymbolTable::readArchives() {
|
|
if (ArchiveQueue.empty())
|
|
return std::error_code();
|
|
|
|
// Add lazy symbols to the symbol table. Lazy symbols that conflict
|
|
// with existing undefined symbols are accumulated in LazySyms.
|
|
std::vector<Symbol *> LazySyms;
|
|
for (ArchiveFile *File : ArchiveQueue) {
|
|
if (Config->Verbose)
|
|
llvm::outs() << "Reading " << File->getShortName() << "\n";
|
|
if (auto EC = File->parse())
|
|
return EC;
|
|
for (Lazy *Sym : File->getLazySymbols())
|
|
addLazy(Sym, &LazySyms);
|
|
}
|
|
ArchiveQueue.clear();
|
|
|
|
// Add archive member files to ObjectQueue that should resolve
|
|
// existing undefined symbols.
|
|
for (Symbol *Sym : LazySyms)
|
|
if (auto EC = addMemberFile(cast<Lazy>(Sym->Body)))
|
|
return EC;
|
|
return std::error_code();
|
|
}
|
|
|
|
std::error_code SymbolTable::readObjects() {
|
|
if (ObjectQueue.empty())
|
|
return std::error_code();
|
|
|
|
// Add defined and undefined symbols to the symbol table.
|
|
std::vector<StringRef> Directives;
|
|
for (size_t I = 0; I < ObjectQueue.size(); ++I) {
|
|
InputFile *File = ObjectQueue[I];
|
|
if (Config->Verbose)
|
|
llvm::outs() << "Reading " << File->getShortName() << "\n";
|
|
if (auto EC = File->parse())
|
|
return EC;
|
|
// Adding symbols may add more files to ObjectQueue
|
|
// (but not to ArchiveQueue).
|
|
for (SymbolBody *Sym : File->getSymbols())
|
|
if (Sym->isExternal())
|
|
if (auto EC = addSymbol(Sym))
|
|
return EC;
|
|
StringRef S = File->getDirectives();
|
|
if (!S.empty())
|
|
Directives.push_back(S);
|
|
}
|
|
ObjectQueue.clear();
|
|
|
|
// Parse directive sections. This may add files to
|
|
// ArchiveQueue and ObjectQueue.
|
|
for (StringRef S : Directives)
|
|
if (auto EC = Driver->parseDirectives(S))
|
|
return EC;
|
|
return std::error_code();
|
|
}
|
|
|
|
bool SymbolTable::reportRemainingUndefines() {
|
|
bool Ret = false;
|
|
for (auto &I : Symtab) {
|
|
Symbol *Sym = I.second;
|
|
auto *Undef = dyn_cast<Undefined>(Sym->Body);
|
|
if (!Undef)
|
|
continue;
|
|
StringRef Name = Undef->getName();
|
|
// The weak alias may have been resovled, so check for that.
|
|
if (SymbolBody *Alias = Undef->WeakAlias) {
|
|
if (auto *D = dyn_cast<Defined>(Alias->getReplacement())) {
|
|
Sym->Body = D;
|
|
continue;
|
|
}
|
|
}
|
|
// If we can resolve a symbol by removing __imp_ prefix, do that.
|
|
// This odd rule is for compatibility with MSVC linker.
|
|
if (Name.startswith("__imp_")) {
|
|
if (Defined *Imp = find(Name.substr(strlen("__imp_")))) {
|
|
auto *S = new (Alloc) DefinedLocalImport(Name, Imp);
|
|
LocalImportChunks.push_back(S->getChunk());
|
|
Sym->Body = S;
|
|
continue;
|
|
}
|
|
}
|
|
llvm::errs() << "undefined symbol: " << Name << "\n";
|
|
// Remaining undefined symbols are not fatal if /force is specified.
|
|
// They are replaced with dummy defined symbols.
|
|
if (Config->Force) {
|
|
Sym->Body = new (Alloc) DefinedAbsolute(Name, 0);
|
|
continue;
|
|
}
|
|
Ret = true;
|
|
}
|
|
return Ret;
|
|
}
|
|
|
|
void SymbolTable::addLazy(Lazy *New, std::vector<Symbol *> *Accum) {
|
|
Symbol *&Sym = Symtab[New->getName()];
|
|
if (!Sym) {
|
|
Sym = new (Alloc) Symbol(New);
|
|
New->setBackref(Sym);
|
|
return;
|
|
}
|
|
SymbolBody *Existing = Sym->Body;
|
|
if (!isa<Undefined>(Existing))
|
|
return;
|
|
Sym->Body = New;
|
|
New->setBackref(Sym);
|
|
Accum->push_back(Sym);
|
|
}
|
|
|
|
std::error_code SymbolTable::addSymbol(SymbolBody *New) {
|
|
// Find an existing symbol or create and insert a new one.
|
|
assert(isa<Defined>(New) || isa<Undefined>(New));
|
|
Symbol *&Sym = Symtab[New->getName()];
|
|
if (!Sym) {
|
|
Sym = new (Alloc) Symbol(New);
|
|
New->setBackref(Sym);
|
|
return std::error_code();
|
|
}
|
|
New->setBackref(Sym);
|
|
|
|
// If we have an undefined symbol and a lazy symbol,
|
|
// let the lazy symbol to read a member file.
|
|
SymbolBody *Existing = Sym->Body;
|
|
if (auto *L = dyn_cast<Lazy>(Existing)) {
|
|
// Undefined symbols with weak aliases need not to be resolved,
|
|
// since they would be replaced with weak aliases if they remain
|
|
// undefined.
|
|
if (auto *U = dyn_cast<Undefined>(New))
|
|
if (!U->WeakAlias)
|
|
return addMemberFile(L);
|
|
Sym->Body = New;
|
|
return std::error_code();
|
|
}
|
|
|
|
// compare() returns -1, 0, or 1 if the lhs symbol is less preferable,
|
|
// equivalent (conflicting), or more preferable, respectively.
|
|
int Comp = Existing->compare(New);
|
|
if (Comp == 0) {
|
|
llvm::errs() << "duplicate symbol: " << Existing->getDebugName()
|
|
<< " and " << New->getDebugName() << "\n";
|
|
return make_error_code(LLDError::DuplicateSymbols);
|
|
}
|
|
if (Comp < 0)
|
|
Sym->Body = New;
|
|
return std::error_code();
|
|
}
|
|
|
|
// Reads an archive member file pointed by a given symbol.
|
|
std::error_code SymbolTable::addMemberFile(Lazy *Body) {
|
|
auto FileOrErr = Body->getMember();
|
|
if (auto EC = FileOrErr.getError())
|
|
return EC;
|
|
std::unique_ptr<InputFile> File = std::move(FileOrErr.get());
|
|
|
|
// getMember returns an empty buffer if the member was already
|
|
// read from the library.
|
|
if (!File)
|
|
return std::error_code();
|
|
if (Config->Verbose)
|
|
llvm::outs() << "Loaded " << File->getShortName() << " for "
|
|
<< Body->getName() << "\n";
|
|
addFile(std::move(File));
|
|
return std::error_code();
|
|
}
|
|
|
|
std::vector<Chunk *> SymbolTable::getChunks() {
|
|
std::vector<Chunk *> Res;
|
|
for (ObjectFile *File : ObjectFiles) {
|
|
std::vector<Chunk *> &V = File->getChunks();
|
|
Res.insert(Res.end(), V.begin(), V.end());
|
|
}
|
|
return Res;
|
|
}
|
|
|
|
Defined *SymbolTable::find(StringRef Name) {
|
|
auto It = Symtab.find(Name);
|
|
if (It == Symtab.end())
|
|
return nullptr;
|
|
if (auto *Def = dyn_cast<Defined>(It->second->Body))
|
|
return Def;
|
|
return nullptr;
|
|
}
|
|
|
|
Symbol *SymbolTable::findSymbol(StringRef Name) {
|
|
auto It = Symtab.find(Name);
|
|
if (It == Symtab.end())
|
|
return nullptr;
|
|
return It->second;
|
|
}
|
|
|
|
void SymbolTable::mangleMaybe(Undefined *U) {
|
|
if (U->WeakAlias)
|
|
return;
|
|
if (!isa<Undefined>(U->getReplacement()))
|
|
return;
|
|
|
|
// In Microsoft ABI, a non-member function name is mangled this way.
|
|
std::string Prefix = ("?" + U->getName() + "@@Y").str();
|
|
for (auto I : Symtab) {
|
|
StringRef Name = I.first;
|
|
Symbol *New = I.second;
|
|
if (!Name.startswith(Prefix))
|
|
continue;
|
|
U->WeakAlias = New->Body;
|
|
if (auto *L = dyn_cast<Lazy>(New->Body))
|
|
addMemberFile(L);
|
|
return;
|
|
}
|
|
}
|
|
|
|
Undefined *SymbolTable::addUndefined(StringRef Name) {
|
|
auto *U = new (Alloc) Undefined(Name);
|
|
addSymbol(U);
|
|
return U;
|
|
}
|
|
|
|
// Resolve To, and make From an alias to To.
|
|
std::error_code SymbolTable::rename(StringRef From, StringRef To) {
|
|
// If From is not undefined, do nothing.
|
|
// Otherwise, rename it to see if To can be resolved instead.
|
|
auto It = Symtab.find(From);
|
|
if (It == Symtab.end())
|
|
return std::error_code();
|
|
Symbol *Sym = It->second;
|
|
if (!isa<Undefined>(Sym->Body))
|
|
return std::error_code();
|
|
SymbolBody *Body = new (Alloc) Undefined(To);
|
|
if (auto EC = addSymbol(Body))
|
|
return EC;
|
|
SymbolBody *Repl = Body->getReplacement();
|
|
if (isa<Undefined>(Repl))
|
|
return std::error_code();
|
|
Sym->Body = Repl;
|
|
Body->setBackref(Sym);
|
|
++Version;
|
|
return std::error_code();
|
|
}
|
|
|
|
void SymbolTable::printMap(llvm::raw_ostream &OS) {
|
|
for (ObjectFile *File : ObjectFiles) {
|
|
OS << File->getShortName() << ":\n";
|
|
for (SymbolBody *Body : File->getSymbols())
|
|
if (auto *R = dyn_cast<DefinedRegular>(Body))
|
|
if (R->isLive())
|
|
OS << Twine::utohexstr(Config->ImageBase + R->getRVA())
|
|
<< " " << R->getName() << "\n";
|
|
}
|
|
}
|
|
|
|
std::error_code SymbolTable::addCombinedLTOObject() {
|
|
if (BitcodeFiles.empty())
|
|
return std::error_code();
|
|
|
|
// Create an object file and add it to the symbol table by replacing any
|
|
// DefinedBitcode symbols with the definitions in the object file.
|
|
LTOCodeGenerator CG;
|
|
auto FileOrErr = createLTOObject(&CG);
|
|
if (auto EC = FileOrErr.getError())
|
|
return EC;
|
|
ObjectFile *Obj = FileOrErr.get();
|
|
|
|
for (SymbolBody *Body : Obj->getSymbols()) {
|
|
if (!Body->isExternal())
|
|
continue;
|
|
// Find an existing Symbol. We should not see any new undefined symbols at
|
|
// this point.
|
|
StringRef Name = Body->getName();
|
|
Symbol *&Sym = Symtab[Name];
|
|
if (!Sym) {
|
|
if (!isa<Defined>(Body)) {
|
|
llvm::errs() << "LTO: undefined symbol: " << Name << '\n';
|
|
return make_error_code(LLDError::BrokenFile);
|
|
}
|
|
Sym = new (Alloc) Symbol(Body);
|
|
Body->setBackref(Sym);
|
|
continue;
|
|
}
|
|
Body->setBackref(Sym);
|
|
|
|
if (isa<DefinedBitcode>(Sym->Body)) {
|
|
// The symbol should now be defined.
|
|
if (!isa<Defined>(Body)) {
|
|
llvm::errs() << "LTO: undefined symbol: " << Name << '\n';
|
|
return make_error_code(LLDError::BrokenFile);
|
|
}
|
|
Sym->Body = Body;
|
|
continue;
|
|
}
|
|
if (auto *L = dyn_cast<Lazy>(Sym->Body)) {
|
|
// We may see new references to runtime library symbols such as __chkstk
|
|
// here. These symbols must be wholly defined in non-bitcode files.
|
|
if (auto EC = addMemberFile(L))
|
|
return EC;
|
|
continue;
|
|
}
|
|
SymbolBody *Existing = Sym->Body;
|
|
int Comp = Existing->compare(Body);
|
|
if (Comp == 0) {
|
|
llvm::errs() << "LTO: unexpected duplicate symbol: " << Name << "\n";
|
|
return make_error_code(LLDError::BrokenFile);
|
|
}
|
|
if (Comp < 0)
|
|
Sym->Body = Body;
|
|
}
|
|
|
|
size_t NumBitcodeFiles = BitcodeFiles.size();
|
|
if (auto EC = run())
|
|
return EC;
|
|
if (BitcodeFiles.size() != NumBitcodeFiles) {
|
|
llvm::errs() << "LTO: late loaded symbol created new bitcode reference\n";
|
|
return make_error_code(LLDError::BrokenFile);
|
|
}
|
|
|
|
// New runtime library symbol references may have created undefined references.
|
|
if (reportRemainingUndefines())
|
|
return make_error_code(LLDError::BrokenFile);
|
|
return std::error_code();
|
|
}
|
|
|
|
// Combine and compile bitcode files and then return the result
|
|
// as a regular COFF object file.
|
|
ErrorOr<ObjectFile *> SymbolTable::createLTOObject(LTOCodeGenerator *CG) {
|
|
// All symbols referenced by non-bitcode objects must be preserved.
|
|
for (ObjectFile *File : ObjectFiles)
|
|
for (SymbolBody *Body : File->getSymbols())
|
|
if (auto *S = dyn_cast<DefinedBitcode>(Body->getReplacement()))
|
|
CG->addMustPreserveSymbol(S->getName());
|
|
|
|
// Likewise for bitcode symbols which we initially resolved to non-bitcode.
|
|
for (BitcodeFile *File : BitcodeFiles)
|
|
for (SymbolBody *Body : File->getSymbols())
|
|
if (isa<DefinedBitcode>(Body) &&
|
|
!isa<DefinedBitcode>(Body->getReplacement()))
|
|
CG->addMustPreserveSymbol(Body->getName());
|
|
|
|
// Likewise for other symbols that must be preserved.
|
|
for (Undefined *U : Config->GCRoot)
|
|
if (isa<DefinedBitcode>(U->getReplacement()))
|
|
CG->addMustPreserveSymbol(U->getName());
|
|
|
|
CG->setModule(BitcodeFiles[0]->releaseModule());
|
|
for (unsigned I = 1, E = BitcodeFiles.size(); I != E; ++I)
|
|
CG->addModule(BitcodeFiles[I]->getModule());
|
|
|
|
std::string ErrMsg;
|
|
LTOMB = CG->compile(false, false, false, ErrMsg); // take MB ownership
|
|
if (!LTOMB) {
|
|
llvm::errs() << ErrMsg << '\n';
|
|
return make_error_code(LLDError::BrokenFile);
|
|
}
|
|
auto *Obj = new ObjectFile(LTOMB->getMemBufferRef());
|
|
Files.emplace_back(Obj);
|
|
ObjectFiles.push_back(Obj);
|
|
if (auto EC = Obj->parse())
|
|
return EC;
|
|
return Obj;
|
|
}
|
|
|
|
} // namespace coff
|
|
} // namespace lld
|