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LinkerScript.cpp
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LinkerScript.cpp
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//===- LinkerScript.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 parses a linker script and write the result to Config or ScriptConfig
// objects.
//
// If SECTIONS command is used, a ScriptConfig contains an AST
// of the command which will later be consumed by createSections() and
// assignAddresses().
//
//===----------------------------------------------------------------------===//
#include "LinkerScript.h"
#include "Config.h"
#include "Driver.h"
#include "InputSection.h"
#include "OutputSections.h"
#include "ScriptParser.h"
#include "Strings.h"
#include "Symbols.h"
#include "SymbolTable.h"
#include "Target.h"
#include "Writer.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/StringSaver.h"
using namespace llvm;
using namespace llvm::ELF;
using namespace llvm::object;
using namespace lld;
using namespace lld::elf;
LinkerScriptBase *elf::ScriptBase;
ScriptConfiguration *elf::ScriptConfig;
template <class ELFT> static void addRegular(SymbolAssignment *Cmd) {
Symbol *Sym = Symtab<ELFT>::X->addRegular(Cmd->Name, STB_GLOBAL, STV_DEFAULT);
Sym->Visibility = Cmd->Hidden ? STV_HIDDEN : STV_DEFAULT;
Cmd->Sym = Sym->body();
}
template <class ELFT> static void addSynthetic(SymbolAssignment *Cmd) {
Symbol *Sym = Symtab<ELFT>::X->addSynthetic(
Cmd->Name, nullptr, 0, Cmd->Hidden ? STV_HIDDEN : STV_DEFAULT);
Cmd->Sym = Sym->body();
}
template <class ELFT> static void addSymbol(SymbolAssignment *Cmd) {
if (Cmd->IsAbsolute)
addRegular<ELFT>(Cmd);
else
addSynthetic<ELFT>(Cmd);
}
// If a symbol was in PROVIDE(), we need to define it only when
// it is an undefined symbol.
template <class ELFT> static bool shouldDefine(SymbolAssignment *Cmd) {
if (Cmd->Name == ".")
return false;
if (!Cmd->Provide)
return true;
SymbolBody *B = Symtab<ELFT>::X->find(Cmd->Name);
return B && B->isUndefined();
}
bool SymbolAssignment::classof(const BaseCommand *C) {
return C->Kind == AssignmentKind;
}
bool OutputSectionCommand::classof(const BaseCommand *C) {
return C->Kind == OutputSectionKind;
}
bool InputSectionDescription::classof(const BaseCommand *C) {
return C->Kind == InputSectionKind;
}
bool AssertCommand::classof(const BaseCommand *C) {
return C->Kind == AssertKind;
}
template <class ELFT> static bool isDiscarded(InputSectionBase<ELFT> *S) {
return !S || !S->Live;
}
template <class ELFT> LinkerScript<ELFT>::LinkerScript() {}
template <class ELFT> LinkerScript<ELFT>::~LinkerScript() {}
template <class ELFT>
bool LinkerScript<ELFT>::shouldKeep(InputSectionBase<ELFT> *S) {
for (Regex *Re : Opt.KeptSections)
if (Re->match(S->Name))
return true;
return false;
}
static bool fileMatches(const InputSectionDescription *Desc,
StringRef Filename) {
return const_cast<Regex &>(Desc->FileRe).match(Filename) &&
!const_cast<Regex &>(Desc->ExcludedFileRe).match(Filename);
}
// Returns input sections filtered by given glob patterns.
template <class ELFT>
std::vector<InputSectionBase<ELFT> *>
LinkerScript<ELFT>::getInputSections(const InputSectionDescription *I) {
const Regex &Re = I->SectionRe;
std::vector<InputSectionBase<ELFT> *> Ret;
for (const std::unique_ptr<ObjectFile<ELFT>> &F :
Symtab<ELFT>::X->getObjectFiles()) {
if (fileMatches(I, sys::path::filename(F->getName())))
for (InputSectionBase<ELFT> *S : F->getSections())
if (!isDiscarded(S) && !S->OutSec &&
const_cast<Regex &>(Re).match(S->Name))
Ret.push_back(S);
}
if (const_cast<Regex &>(Re).match("COMMON"))
Ret.push_back(CommonInputSection<ELFT>::X);
return Ret;
}
static bool compareName(InputSectionData *A, InputSectionData *B) {
return A->Name < B->Name;
}
static bool compareAlignment(InputSectionData *A, InputSectionData *B) {
// ">" is not a mistake. Larger alignments are placed before smaller
// alignments in order to reduce the amount of padding necessary.
// This is compatible with GNU.
return A->Alignment > B->Alignment;
}
static std::function<bool(InputSectionData *, InputSectionData *)>
getComparator(SortKind K) {
if (K == SortByName)
return compareName;
return compareAlignment;
}
template <class ELFT>
void LinkerScript<ELFT>::discard(OutputSectionCommand &Cmd) {
for (const std::unique_ptr<BaseCommand> &Base : Cmd.Commands) {
if (auto *Cmd = dyn_cast<InputSectionDescription>(Base.get())) {
for (InputSectionBase<ELFT> *S : getInputSections(Cmd)) {
S->Live = false;
reportDiscarded(S);
}
}
}
}
static bool checkConstraint(uint64_t Flags, ConstraintKind Kind) {
bool RO = (Kind == ConstraintKind::ReadOnly);
bool RW = (Kind == ConstraintKind::ReadWrite);
bool Writable = Flags & SHF_WRITE;
return !(RO && Writable) && !(RW && !Writable);
}
template <class ELFT>
static bool matchConstraints(ArrayRef<InputSectionBase<ELFT> *> Sections,
ConstraintKind Kind) {
if (Kind == ConstraintKind::NoConstraint)
return true;
return llvm::all_of(Sections, [=](InputSectionBase<ELFT> *Sec) {
return checkConstraint(Sec->getSectionHdr()->sh_flags, Kind);
});
}
template <class ELFT>
std::vector<InputSectionBase<ELFT> *>
LinkerScript<ELFT>::createInputSectionList(OutputSectionCommand &OutCmd) {
std::vector<InputSectionBase<ELFT> *> Ret;
DenseSet<InputSectionBase<ELFT> *> SectionIndex;
for (const std::unique_ptr<BaseCommand> &Base : OutCmd.Commands) {
if (auto *OutCmd = dyn_cast<SymbolAssignment>(Base.get())) {
if (shouldDefine<ELFT>(OutCmd))
addSymbol<ELFT>(OutCmd);
OutCmd->GoesAfter = Ret.empty() ? nullptr : Ret.back();
continue;
}
auto *Cmd = cast<InputSectionDescription>(Base.get());
std::vector<InputSectionBase<ELFT> *> V = getInputSections(Cmd);
if (!matchConstraints<ELFT>(V, OutCmd.Constraint))
continue;
if (Cmd->SortInner)
std::stable_sort(V.begin(), V.end(), getComparator(Cmd->SortInner));
if (Cmd->SortOuter)
std::stable_sort(V.begin(), V.end(), getComparator(Cmd->SortOuter));
// Add all input sections corresponding to rule 'Cmd' to
// resulting vector. We do not add duplicate input sections.
for (InputSectionBase<ELFT> *S : V)
if (SectionIndex.insert(S).second)
Ret.push_back(S);
}
return Ret;
}
template <class ELFT> void LinkerScript<ELFT>::createAssignments() {
for (const std::unique_ptr<SymbolAssignment> &Cmd : Opt.Assignments) {
if (shouldDefine<ELFT>(Cmd.get()))
addRegular<ELFT>(Cmd.get());
if (Cmd->Sym)
cast<DefinedRegular<ELFT>>(Cmd->Sym)->Value = Cmd->Expression(0);
}
}
template <class ELFT>
void LinkerScript<ELFT>::createSections(OutputSectionFactory<ELFT> &Factory) {
for (const std::unique_ptr<BaseCommand> &Base1 : Opt.Commands) {
if (auto *Cmd = dyn_cast<SymbolAssignment>(Base1.get())) {
if (shouldDefine<ELFT>(Cmd))
addRegular<ELFT>(Cmd);
continue;
}
if (auto *Cmd = dyn_cast<OutputSectionCommand>(Base1.get())) {
if (Cmd->Name == "/DISCARD/") {
discard(*Cmd);
continue;
}
std::vector<InputSectionBase<ELFT> *> V = createInputSectionList(*Cmd);
if (V.empty())
continue;
for (InputSectionBase<ELFT> *Sec : V) {
OutputSectionBase<ELFT> *OutSec;
bool IsNew;
std::tie(OutSec, IsNew) = Factory.create(Sec, Cmd->Name);
if (IsNew)
OutputSections->push_back(OutSec);
uint32_t Subalign = Cmd->SubalignExpr ? Cmd->SubalignExpr(0) : 0;
if (Subalign)
Sec->Alignment = Subalign;
OutSec->addSection(Sec);
}
}
}
// Add orphan sections.
for (const std::unique_ptr<ObjectFile<ELFT>> &F :
Symtab<ELFT>::X->getObjectFiles()) {
for (InputSectionBase<ELFT> *S : F->getSections()) {
if (isDiscarded(S) || S->OutSec)
continue;
OutputSectionBase<ELFT> *OutSec;
bool IsNew;
std::tie(OutSec, IsNew) = Factory.create(S, getOutputSectionName(S));
if (IsNew)
OutputSections->push_back(OutSec);
OutSec->addSection(S);
}
}
}
// Sets value of a section-defined symbol. Two kinds of
// symbols are processed: synthetic symbols, whose value
// is an offset from beginning of section and regular
// symbols whose value is absolute.
template <class ELFT>
static void assignSectionSymbol(SymbolAssignment *Cmd,
OutputSectionBase<ELFT> *Sec,
typename ELFT::uint Off) {
if (!Cmd->Sym)
return;
if (auto *Body = dyn_cast<DefinedSynthetic<ELFT>>(Cmd->Sym)) {
Body->Section = Sec;
Body->Value = Cmd->Expression(Sec->getVA() + Off) - Sec->getVA();
return;
}
auto *Body = cast<DefinedRegular<ELFT>>(Cmd->Sym);
Body->Value = Cmd->Expression(Sec->getVA() + Off);
}
// Linker script may define start and end symbols for special section types,
// like .got, .eh_frame_hdr, .eh_frame and others. Those sections are not a list
// of regular input input sections, therefore our way of defining symbols for
// regular sections will not work. The approach we use for special section types
// is not perfect - it handles only start and end symbols.
template <class ELFT>
void addStartEndSymbols(OutputSectionCommand *Cmd,
OutputSectionBase<ELFT> *Sec) {
bool Start = true;
BaseCommand *PrevCmd = nullptr;
for (std::unique_ptr<BaseCommand> &Base : Cmd->Commands) {
if (auto *AssignCmd = dyn_cast<SymbolAssignment>(Base.get())) {
assignSectionSymbol<ELFT>(AssignCmd, Sec, Start ? 0 : Sec->getSize());
} else {
if (!Start && isa<SymbolAssignment>(PrevCmd))
error("section '" + Sec->getName() +
"' supports only start and end symbols");
Start = false;
}
PrevCmd = Base.get();
}
}
template <class ELFT>
void assignOffsets(OutputSectionCommand *Cmd, OutputSectionBase<ELFT> *Sec) {
auto *OutSec = dyn_cast<OutputSection<ELFT>>(Sec);
if (!OutSec) {
Sec->assignOffsets();
// This section is not regular output section. However linker script may
// have defined start/end symbols for it. This case is handled below.
addStartEndSymbols(Cmd, Sec);
return;
}
typedef typename ELFT::uint uintX_t;
uintX_t Off = 0;
auto ItCmd = Cmd->Commands.begin();
// Assigns values to all symbols following the given
// input section 'D' in output section 'Sec'. When symbols
// are in the beginning of output section the value of 'D'
// is nullptr.
auto AssignSuccessors = [&](InputSectionData *D) {
for (; ItCmd != Cmd->Commands.end(); ++ItCmd) {
auto *AssignCmd = dyn_cast<SymbolAssignment>(ItCmd->get());
if (!AssignCmd)
continue;
if (D != AssignCmd->GoesAfter)
break;
if (AssignCmd->Name == ".") {
// Update to location counter means update to section size.
Off = AssignCmd->Expression(Sec->getVA() + Off) - Sec->getVA();
Sec->setSize(Off);
continue;
}
assignSectionSymbol<ELFT>(AssignCmd, Sec, Off);
}
};
AssignSuccessors(nullptr);
for (InputSection<ELFT> *I : OutSec->Sections) {
Off = alignTo(Off, I->Alignment);
I->OutSecOff = Off;
Off += I->getSize();
// Update section size inside for-loop, so that SIZEOF
// works correctly in the case below:
// .foo { *(.aaa) a = SIZEOF(.foo); *(.bbb) }
Sec->setSize(Off);
// Add symbols following current input section.
AssignSuccessors(I);
}
}
template <class ELFT>
static std::vector<OutputSectionBase<ELFT> *>
findSections(OutputSectionCommand &Cmd,
ArrayRef<OutputSectionBase<ELFT> *> Sections) {
std::vector<OutputSectionBase<ELFT> *> Ret;
for (OutputSectionBase<ELFT> *Sec : Sections)
if (Sec->getName() == Cmd.Name &&
checkConstraint(Sec->getFlags(), Cmd.Constraint))
Ret.push_back(Sec);
return Ret;
}
template <class ELFT> void LinkerScript<ELFT>::assignAddresses() {
// Orphan sections are sections present in the input files which
// are not explicitly placed into the output file by the linker script.
// We place orphan sections at end of file.
// Other linkers places them using some heuristics as described in
// https://sourceware.org/binutils/docs/ld/Orphan-Sections.html#Orphan-Sections.
for (OutputSectionBase<ELFT> *Sec : *OutputSections) {
StringRef Name = Sec->getName();
if (getSectionIndex(Name) == INT_MAX)
Opt.Commands.push_back(llvm::make_unique<OutputSectionCommand>(Name));
}
// Assign addresses as instructed by linker script SECTIONS sub-commands.
Dot = getHeaderSize();
uintX_t MinVA = std::numeric_limits<uintX_t>::max();
uintX_t ThreadBssOffset = 0;
for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands) {
if (auto *Cmd = dyn_cast<SymbolAssignment>(Base.get())) {
if (Cmd->Name == ".") {
Dot = Cmd->Expression(Dot);
} else if (Cmd->Sym) {
cast<DefinedRegular<ELFT>>(Cmd->Sym)->Value = Cmd->Expression(Dot);
}
continue;
}
if (auto *Cmd = dyn_cast<AssertCommand>(Base.get())) {
Cmd->Expression(Dot);
continue;
}
auto *Cmd = cast<OutputSectionCommand>(Base.get());
for (OutputSectionBase<ELFT> *Sec :
findSections<ELFT>(*Cmd, *OutputSections)) {
if (Cmd->AddrExpr)
Dot = Cmd->AddrExpr(Dot);
if (Cmd->AlignExpr)
Sec->updateAlignment(Cmd->AlignExpr(Dot));
if ((Sec->getFlags() & SHF_TLS) && Sec->getType() == SHT_NOBITS) {
uintX_t TVA = Dot + ThreadBssOffset;
TVA = alignTo(TVA, Sec->getAlignment());
Sec->setVA(TVA);
assignOffsets(Cmd, Sec);
ThreadBssOffset = TVA - Dot + Sec->getSize();
continue;
}
if (!(Sec->getFlags() & SHF_ALLOC)) {
assignOffsets(Cmd, Sec);
continue;
}
Dot = alignTo(Dot, Sec->getAlignment());
Sec->setVA(Dot);
assignOffsets(Cmd, Sec);
MinVA = std::min(MinVA, Dot);
Dot += Sec->getSize();
}
}
// ELF and Program headers need to be right before the first section in
// memory. Set their addresses accordingly.
MinVA = alignDown(MinVA - Out<ELFT>::ElfHeader->getSize() -
Out<ELFT>::ProgramHeaders->getSize(),
Target->PageSize);
Out<ELFT>::ElfHeader->setVA(MinVA);
Out<ELFT>::ProgramHeaders->setVA(Out<ELFT>::ElfHeader->getSize() + MinVA);
}
// Creates program headers as instructed by PHDRS linker script command.
template <class ELFT>
std::vector<PhdrEntry<ELFT>> LinkerScript<ELFT>::createPhdrs() {
std::vector<PhdrEntry<ELFT>> Ret;
// Process PHDRS and FILEHDR keywords because they are not
// real output sections and cannot be added in the following loop.
for (const PhdrsCommand &Cmd : Opt.PhdrsCommands) {
Ret.emplace_back(Cmd.Type, Cmd.Flags == UINT_MAX ? PF_R : Cmd.Flags);
PhdrEntry<ELFT> &Phdr = Ret.back();
if (Cmd.HasFilehdr)
Phdr.add(Out<ELFT>::ElfHeader);
if (Cmd.HasPhdrs)
Phdr.add(Out<ELFT>::ProgramHeaders);
if (Cmd.LMAExpr) {
Phdr.H.p_paddr = Cmd.LMAExpr(0);
Phdr.HasLMA = true;
}
}
// Add output sections to program headers.
PhdrEntry<ELFT> *Load = nullptr;
uintX_t Flags = PF_R;
for (OutputSectionBase<ELFT> *Sec : *OutputSections) {
if (!(Sec->getFlags() & SHF_ALLOC))
break;
std::vector<size_t> PhdrIds = getPhdrIndices(Sec->getName());
if (!PhdrIds.empty()) {
// Assign headers specified by linker script
for (size_t Id : PhdrIds) {
Ret[Id].add(Sec);
if (Opt.PhdrsCommands[Id].Flags == UINT_MAX)
Ret[Id].H.p_flags |= Sec->getPhdrFlags();
}
} else {
// If we have no load segment or flags've changed then we want new load
// segment.
uintX_t NewFlags = Sec->getPhdrFlags();
if (Load == nullptr || Flags != NewFlags) {
Load = &*Ret.emplace(Ret.end(), PT_LOAD, NewFlags);
Flags = NewFlags;
}
Load->add(Sec);
}
}
return Ret;
}
template <class ELFT> bool LinkerScript<ELFT>::ignoreInterpSection() {
// Ignore .interp section in case we have PHDRS specification
// and PT_INTERP isn't listed.
return !Opt.PhdrsCommands.empty() &&
llvm::find_if(Opt.PhdrsCommands, [](const PhdrsCommand &Cmd) {
return Cmd.Type == PT_INTERP;
}) == Opt.PhdrsCommands.end();
}
template <class ELFT>
ArrayRef<uint8_t> LinkerScript<ELFT>::getFiller(StringRef Name) {
for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands)
if (auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get()))
if (Cmd->Name == Name)
return Cmd->Filler;
return {};
}
template <class ELFT> Expr LinkerScript<ELFT>::getLma(StringRef Name) {
for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands)
if (auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get()))
if (Cmd->LmaExpr && Cmd->Name == Name)
return Cmd->LmaExpr;
return {};
}
// Returns the index of the given section name in linker script
// SECTIONS commands. Sections are laid out as the same order as they
// were in the script. If a given name did not appear in the script,
// it returns INT_MAX, so that it will be laid out at end of file.
template <class ELFT> int LinkerScript<ELFT>::getSectionIndex(StringRef Name) {
int I = 0;
for (std::unique_ptr<BaseCommand> &Base : Opt.Commands) {
if (auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get()))
if (Cmd->Name == Name)
return I;
++I;
}
return INT_MAX;
}
// A compartor to sort output sections. Returns -1 or 1 if
// A or B are mentioned in linker script. Otherwise, returns 0.
template <class ELFT>
int LinkerScript<ELFT>::compareSections(StringRef A, StringRef B) {
int I = getSectionIndex(A);
int J = getSectionIndex(B);
if (I == INT_MAX && J == INT_MAX)
return 0;
return I < J ? -1 : 1;
}
template <class ELFT> bool LinkerScript<ELFT>::hasPhdrsCommands() {
return !Opt.PhdrsCommands.empty();
}
template <class ELFT>
uint64_t LinkerScript<ELFT>::getOutputSectionAddress(StringRef Name) {
for (OutputSectionBase<ELFT> *Sec : *OutputSections)
if (Sec->getName() == Name)
return Sec->getVA();
error("undefined section " + Name);
return 0;
}
template <class ELFT>
uint64_t LinkerScript<ELFT>::getOutputSectionSize(StringRef Name) {
for (OutputSectionBase<ELFT> *Sec : *OutputSections)
if (Sec->getName() == Name)
return Sec->getSize();
error("undefined section " + Name);
return 0;
}
template <class ELFT>
uint64_t LinkerScript<ELFT>::getOutputSectionAlign(StringRef Name) {
for (OutputSectionBase<ELFT> *Sec : *OutputSections)
if (Sec->getName() == Name)
return Sec->getAlignment();
error("undefined section " + Name);
return 0;
}
template <class ELFT> uint64_t LinkerScript<ELFT>::getHeaderSize() {
return Out<ELFT>::ElfHeader->getSize() + Out<ELFT>::ProgramHeaders->getSize();
}
template <class ELFT> uint64_t LinkerScript<ELFT>::getSymbolValue(StringRef S) {
if (SymbolBody *B = Symtab<ELFT>::X->find(S))
return B->getVA<ELFT>();
error("symbol not found: " + S);
return 0;
}
// Returns indices of ELF headers containing specific section, identified
// by Name. Each index is a zero based number of ELF header listed within
// PHDRS {} script block.
template <class ELFT>
std::vector<size_t> LinkerScript<ELFT>::getPhdrIndices(StringRef SectionName) {
for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands) {
auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get());
if (!Cmd || Cmd->Name != SectionName)
continue;
std::vector<size_t> Ret;
for (StringRef PhdrName : Cmd->Phdrs)
Ret.push_back(getPhdrIndex(PhdrName));
return Ret;
}
return {};
}
template <class ELFT>
size_t LinkerScript<ELFT>::getPhdrIndex(StringRef PhdrName) {
size_t I = 0;
for (PhdrsCommand &Cmd : Opt.PhdrsCommands) {
if (Cmd.Name == PhdrName)
return I;
++I;
}
error("section header '" + PhdrName + "' is not listed in PHDRS");
return 0;
}
class elf::ScriptParser : public ScriptParserBase {
typedef void (ScriptParser::*Handler)();
public:
ScriptParser(StringRef S, bool B) : ScriptParserBase(S), IsUnderSysroot(B) {}
void readLinkerScript();
void readVersionScript();
private:
void addFile(StringRef Path);
void readAsNeeded();
void readEntry();
void readExtern();
void readGroup();
void readInclude();
void readOutput();
void readOutputArch();
void readOutputFormat();
void readPhdrs();
void readSearchDir();
void readSections();
void readVersion();
void readVersionScriptCommand();
SymbolAssignment *readAssignment(StringRef Name);
std::vector<uint8_t> readFill();
OutputSectionCommand *readOutputSectionDescription(StringRef OutSec);
std::vector<uint8_t> readOutputSectionFiller(StringRef Tok);
std::vector<StringRef> readOutputSectionPhdrs();
InputSectionDescription *readInputSectionDescription(StringRef Tok);
Regex readFilePatterns();
InputSectionDescription *readInputSectionRules(StringRef FilePattern);
unsigned readPhdrType();
SortKind readSortKind();
SymbolAssignment *readProvideHidden(bool Provide, bool Hidden);
SymbolAssignment *readProvideOrAssignment(StringRef Tok, bool MakeAbsolute);
void readSort();
Expr readAssert();
Expr readExpr();
Expr readExpr1(Expr Lhs, int MinPrec);
Expr readPrimary();
Expr readTernary(Expr Cond);
Expr readParenExpr();
// For parsing version script.
void readExtern(std::vector<SymbolVersion> *Globals);
void readVersionDeclaration(StringRef VerStr);
void readGlobal(StringRef VerStr);
void readLocal();
ScriptConfiguration &Opt = *ScriptConfig;
StringSaver Saver = {ScriptConfig->Alloc};
bool IsUnderSysroot;
};
void ScriptParser::readVersionScript() {
readVersionScriptCommand();
if (!atEOF())
setError("EOF expected, but got " + next());
}
void ScriptParser::readVersionScriptCommand() {
if (skip("{")) {
readVersionDeclaration("");
return;
}
while (!atEOF() && !Error && peek() != "}") {
StringRef VerStr = next();
if (VerStr == "{") {
setError("anonymous version definition is used in "
"combination with other version definitions");
return;
}
expect("{");
readVersionDeclaration(VerStr);
}
}
void ScriptParser::readVersion() {
expect("{");
readVersionScriptCommand();
expect("}");
}
void ScriptParser::readLinkerScript() {
while (!atEOF()) {
StringRef Tok = next();
if (Tok == ";")
continue;
if (Tok == "ENTRY") {
readEntry();
} else if (Tok == "EXTERN") {
readExtern();
} else if (Tok == "GROUP" || Tok == "INPUT") {
readGroup();
} else if (Tok == "INCLUDE") {
readInclude();
} else if (Tok == "OUTPUT") {
readOutput();
} else if (Tok == "OUTPUT_ARCH") {
readOutputArch();
} else if (Tok == "OUTPUT_FORMAT") {
readOutputFormat();
} else if (Tok == "PHDRS") {
readPhdrs();
} else if (Tok == "SEARCH_DIR") {
readSearchDir();
} else if (Tok == "SECTIONS") {
readSections();
} else if (Tok == "VERSION") {
readVersion();
} else if (SymbolAssignment *Cmd = readProvideOrAssignment(Tok, true)) {
if (Opt.HasContents)
Opt.Commands.emplace_back(Cmd);
else
Opt.Assignments.emplace_back(Cmd);
} else {
setError("unknown directive: " + Tok);
}
}
}
void ScriptParser::addFile(StringRef S) {
if (IsUnderSysroot && S.startswith("/")) {
SmallString<128> Path;
(Config->Sysroot + S).toStringRef(Path);
if (sys::fs::exists(Path)) {
Driver->addFile(Saver.save(Path.str()));
return;
}
}
if (sys::path::is_absolute(S)) {
Driver->addFile(S);
} else if (S.startswith("=")) {
if (Config->Sysroot.empty())
Driver->addFile(S.substr(1));
else
Driver->addFile(Saver.save(Config->Sysroot + "/" + S.substr(1)));
} else if (S.startswith("-l")) {
Driver->addLibrary(S.substr(2));
} else if (sys::fs::exists(S)) {
Driver->addFile(S);
} else {
std::string Path = findFromSearchPaths(S);
if (Path.empty())
setError("unable to find " + S);
else
Driver->addFile(Saver.save(Path));
}
}
void ScriptParser::readAsNeeded() {
expect("(");
bool Orig = Config->AsNeeded;
Config->AsNeeded = true;
while (!Error && !skip(")"))
addFile(next());
Config->AsNeeded = Orig;
}
void ScriptParser::readEntry() {
// -e <symbol> takes predecence over ENTRY(<symbol>).
expect("(");
StringRef Tok = next();
if (Config->Entry.empty())
Config->Entry = Tok;
expect(")");
}
void ScriptParser::readExtern() {
expect("(");
while (!Error && !skip(")"))
Config->Undefined.push_back(next());
}
void ScriptParser::readGroup() {
expect("(");
while (!Error && !skip(")")) {
StringRef Tok = next();
if (Tok == "AS_NEEDED")
readAsNeeded();
else
addFile(Tok);
}
}
void ScriptParser::readInclude() {
StringRef Tok = next();
auto MBOrErr = MemoryBuffer::getFile(Tok);
if (!MBOrErr) {
setError("cannot open " + Tok);
return;
}
std::unique_ptr<MemoryBuffer> &MB = *MBOrErr;
StringRef S = Saver.save(MB->getMemBufferRef().getBuffer());
std::vector<StringRef> V = tokenize(S);
Tokens.insert(Tokens.begin() + Pos, V.begin(), V.end());
}
void ScriptParser::readOutput() {
// -o <file> takes predecence over OUTPUT(<file>).
expect("(");
StringRef Tok = next();
if (Config->OutputFile.empty())
Config->OutputFile = Tok;
expect(")");
}
void ScriptParser::readOutputArch() {
// Error checking only for now.
expect("(");
next();
expect(")");
}
void ScriptParser::readOutputFormat() {
// Error checking only for now.
expect("(");
next();
StringRef Tok = next();
if (Tok == ")")
return;
if (Tok != ",") {
setError("unexpected token: " + Tok);
return;
}
next();
expect(",");
next();
expect(")");
}
void ScriptParser::readPhdrs() {
expect("{");
while (!Error && !skip("}")) {
StringRef Tok = next();
Opt.PhdrsCommands.push_back(
{Tok, PT_NULL, false, false, UINT_MAX, nullptr});
PhdrsCommand &PhdrCmd = Opt.PhdrsCommands.back();
PhdrCmd.Type = readPhdrType();
do {
Tok = next();
if (Tok == ";")
break;
if (Tok == "FILEHDR")
PhdrCmd.HasFilehdr = true;
else if (Tok == "PHDRS")
PhdrCmd.HasPhdrs = true;
else if (Tok == "AT")
PhdrCmd.LMAExpr = readParenExpr();
else if (Tok == "FLAGS") {
expect("(");
// Passing 0 for the value of dot is a bit of a hack. It means that
// we accept expressions like ".|1".
PhdrCmd.Flags = readExpr()(0);
expect(")");
} else
setError("unexpected header attribute: " + Tok);
} while (!Error);
}
}
void ScriptParser::readSearchDir() {
expect("(");
StringRef Tok = next();
if (!Config->Nostdlib)
Config->SearchPaths.push_back(Tok);
expect(")");
}
void ScriptParser::readSections() {
Opt.HasContents = true;
expect("{");
while (!Error && !skip("}")) {
StringRef Tok = next();
BaseCommand *Cmd = readProvideOrAssignment(Tok, true);
if (!Cmd) {
if (Tok == "ASSERT")
Cmd = new AssertCommand(readAssert());
else
Cmd = readOutputSectionDescription(Tok);
}
Opt.Commands.emplace_back(Cmd);
}
}
static int precedence(StringRef Op) {
return StringSwitch<int>(Op)
.Case("*", 4)
.Case("/", 4)
.Case("+", 3)
.Case("-", 3)
.Case("<", 2)
.Case(">", 2)
.Case(">=", 2)
.Case("<=", 2)
.Case("==", 2)
.Case("!=", 2)
.Case("&", 1)
.Case("|", 1)
.Default(-1);
}
Regex ScriptParser::readFilePatterns() {
std::vector<StringRef> V;
while (!Error && !skip(")"))
V.push_back(next());
return compileGlobPatterns(V);
}
SortKind ScriptParser::readSortKind() {
if (skip("SORT") || skip("SORT_BY_NAME"))
return SortByName;
if (skip("SORT_BY_ALIGNMENT"))
return SortByAlignment;
return SortNone;
}
InputSectionDescription *
ScriptParser::readInputSectionRules(StringRef FilePattern) {
auto *Cmd = new InputSectionDescription(FilePattern);
expect("(");
// Read EXCLUDE_FILE().
if (skip("EXCLUDE_FILE")) {
expect("(");
Cmd->ExcludedFileRe = readFilePatterns();
}
// Read SORT().
if (SortKind K1 = readSortKind()) {
Cmd->SortOuter = K1;
expect("(");
if (SortKind K2 = readSortKind()) {
Cmd->SortInner = K2;
expect("(");
Cmd->SectionRe = readFilePatterns();
expect(")");
} else {
Cmd->SectionRe = readFilePatterns();
}
expect(")");
return Cmd;
}
Cmd->SectionRe = readFilePatterns();
return Cmd;
}
InputSectionDescription *
ScriptParser::readInputSectionDescription(StringRef Tok) {
// Input section wildcard can be surrounded by KEEP.
// https://sourceware.org/binutils/docs/ld/Input-Section-Keep.html#Input-Section-Keep
if (Tok == "KEEP") {
expect("(");
StringRef FilePattern = next();
InputSectionDescription *Cmd = readInputSectionRules(FilePattern);
expect(")");
Opt.KeptSections.push_back(&Cmd->SectionRe);
return Cmd;
}
return readInputSectionRules(Tok);
}
void ScriptParser::readSort() {
expect("(");
expect("CONSTRUCTORS");
expect(")");