Remove LLVM 8.0.1 files.

1 files changed, 0 insertions, 1144 deletions

diff --git a/gnu/llvm/tools/lld/ELF/LinkerScript.cpp b/gnu/llvm/tools/lld/ELF/LinkerScript.cpp
deleted file mode 100644
index 483498dc522..00000000000
--- a/gnu/llvm/tools/lld/ELF/LinkerScript.cpp
+++ /dev/null
@@ -1,1144 +0,0 @@
-//===- 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.
-//
-//===----------------------------------------------------------------------===//
-
-#include "LinkerScript.h"
-#include "Config.h"
-#include "InputSection.h"
-#include "OutputSections.h"
-#include "SymbolTable.h"
-#include "Symbols.h"
-#include "SyntheticSections.h"
-#include "Target.h"
-#include "Writer.h"
-#include "lld/Common/Memory.h"
-#include "lld/Common/Strings.h"
-#include "lld/Common/Threads.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/BinaryFormat/ELF.h"
-#include "llvm/Support/Casting.h"
-#include "llvm/Support/Endian.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/FileSystem.h"
-#include "llvm/Support/Path.h"
-#include <algorithm>
-#include <cassert>
-#include <cstddef>
-#include <cstdint>
-#include <iterator>
-#include <limits>
-#include <string>
-#include <vector>
-
-using namespace llvm;
-using namespace llvm::ELF;
-using namespace llvm::object;
-using namespace llvm::support::endian;
-using namespace lld;
-using namespace lld::elf;
-
-LinkerScript *elf::Script;
-
-static uint64_t getOutputSectionVA(SectionBase *InputSec, StringRef Loc) {
-  if (OutputSection *OS = InputSec->getOutputSection())
-    return OS->Addr;
-  error(Loc + ": unable to evaluate expression: input section " +
-        InputSec->Name + " has no output section assigned");
-  return 0;
-}
-
-uint64_t ExprValue::getValue() const {
-  if (Sec)
-    return alignTo(Sec->getOffset(Val) + getOutputSectionVA(Sec, Loc),
-                   Alignment);
-  return alignTo(Val, Alignment);
-}
-
-uint64_t ExprValue::getSecAddr() const {
-  if (Sec)
-    return Sec->getOffset(0) + getOutputSectionVA(Sec, Loc);
-  return 0;
-}
-
-uint64_t ExprValue::getSectionOffset() const {
-  // If the alignment is trivial, we don't have to compute the full
-  // value to know the offset. This allows this function to succeed in
-  // cases where the output section is not yet known.
-  if (Alignment == 1 && (!Sec || !Sec->getOutputSection()))
-    return Val;
-  return getValue() - getSecAddr();
-}
-
-OutputSection *LinkerScript::createOutputSection(StringRef Name,
-                                                 StringRef Location) {
-  OutputSection *&SecRef = NameToOutputSection[Name];
-  OutputSection *Sec;
-  if (SecRef && SecRef->Location.empty()) {
-    // There was a forward reference.
-    Sec = SecRef;
-  } else {
-    Sec = make<OutputSection>(Name, SHT_NOBITS, 0);
-    if (!SecRef)
-      SecRef = Sec;
-  }
-  Sec->Location = Location;
-  return Sec;
-}
-
-OutputSection *LinkerScript::getOrCreateOutputSection(StringRef Name) {
-  OutputSection *&CmdRef = NameToOutputSection[Name];
-  if (!CmdRef)
-    CmdRef = make<OutputSection>(Name, SHT_PROGBITS, 0);
-  return CmdRef;
-}
-
-// Expands the memory region by the specified size.
-static void expandMemoryRegion(MemoryRegion *MemRegion, uint64_t Size,
-                               StringRef RegionName, StringRef SecName) {
-  MemRegion->CurPos += Size;
-  uint64_t NewSize = MemRegion->CurPos - MemRegion->Origin;
-  if (NewSize > MemRegion->Length)
-    error("section '" + SecName + "' will not fit in region '" + RegionName +
-          "': overflowed by " + Twine(NewSize - MemRegion->Length) + " bytes");
-}
-
-void LinkerScript::expandMemoryRegions(uint64_t Size) {
-  if (Ctx->MemRegion)
-    expandMemoryRegion(Ctx->MemRegion, Size, Ctx->MemRegion->Name,
-                       Ctx->OutSec->Name);
-  // Only expand the LMARegion if it is different from MemRegion.
-  if (Ctx->LMARegion && Ctx->MemRegion != Ctx->LMARegion)
-    expandMemoryRegion(Ctx->LMARegion, Size, Ctx->LMARegion->Name,
-                       Ctx->OutSec->Name);
-}
-
-void LinkerScript::expandOutputSection(uint64_t Size) {
-  Ctx->OutSec->Size += Size;
-  expandMemoryRegions(Size);
-}
-
-void LinkerScript::setDot(Expr E, const Twine &Loc, bool InSec) {
-  uint64_t Val = E().getValue();
-  if (Val < Dot && InSec)
-    error(Loc + ": unable to move location counter backward for: " +
-          Ctx->OutSec->Name);
-
-  // Update to location counter means update to section size.
-  if (InSec)
-    expandOutputSection(Val - Dot);
-  else
-    expandMemoryRegions(Val - Dot);
-
-  Dot = Val;
-}
-
-// Used for handling linker symbol assignments, for both finalizing
-// their values and doing early declarations. Returns true if symbol
-// should be defined from linker script.
-static bool shouldDefineSym(SymbolAssignment *Cmd) {
-  if (Cmd->Name == ".")
-    return false;
-
-  if (!Cmd->Provide)
-    return true;
-
-  // If a symbol was in PROVIDE(), we need to define it only
-  // when it is a referenced undefined symbol.
-  Symbol *B = Symtab->find(Cmd->Name);
-  if (B && !B->isDefined())
-    return true;
-  return false;
-}
-
-// This function is called from processSectionCommands,
-// while we are fixing the output section layout.
-void LinkerScript::addSymbol(SymbolAssignment *Cmd) {
-  if (!shouldDefineSym(Cmd))
-    return;
-
-  // Define a symbol.
-  Symbol *Sym;
-  uint8_t Visibility = Cmd->Hidden ? STV_HIDDEN : STV_DEFAULT;
-  std::tie(Sym, std::ignore) = Symtab->insert(Cmd->Name, Visibility,
-                                              /*CanOmitFromDynSym*/ false,
-                                              /*File*/ nullptr);
-  ExprValue Value = Cmd->Expression();
-  SectionBase *Sec = Value.isAbsolute() ? nullptr : Value.Sec;
-
-  // When this function is called, section addresses have not been
-  // fixed yet. So, we may or may not know the value of the RHS
-  // expression.
-  //
-  // For example, if an expression is `x = 42`, we know x is always 42.
-  // However, if an expression is `x = .`, there's no way to know its
-  // value at the moment.
-  //
-  // We want to set symbol values early if we can. This allows us to
-  // use symbols as variables in linker scripts. Doing so allows us to
-  // write expressions like this: `alignment = 16; . = ALIGN(., alignment)`.
-  uint64_t SymValue = Value.Sec ? 0 : Value.getValue();
-
-  replaceSymbol<Defined>(Sym, nullptr, Cmd->Name, STB_GLOBAL, Visibility,
-                         STT_NOTYPE, SymValue, 0, Sec);
-  Cmd->Sym = cast<Defined>(Sym);
-}
-
-// This function is called from LinkerScript::declareSymbols.
-// It creates a placeholder symbol if needed.
-static void declareSymbol(SymbolAssignment *Cmd) {
-  if (!shouldDefineSym(Cmd))
-    return;
-
-  // We can't calculate final value right now.
-  Symbol *Sym;
-  uint8_t Visibility = Cmd->Hidden ? STV_HIDDEN : STV_DEFAULT;
-  std::tie(Sym, std::ignore) = Symtab->insert(Cmd->Name, Visibility,
-                                              /*CanOmitFromDynSym*/ false,
-                                              /*File*/ nullptr);
-  replaceSymbol<Defined>(Sym, nullptr, Cmd->Name, STB_GLOBAL, Visibility,
-                         STT_NOTYPE, 0, 0, nullptr);
-  Cmd->Sym = cast<Defined>(Sym);
-  Cmd->Provide = false;
-  Sym->ScriptDefined = true;
-}
-
-// This method is used to handle INSERT AFTER statement. Here we rebuild
-// the list of script commands to mix sections inserted into.
-void LinkerScript::processInsertCommands() {
-  std::vector<BaseCommand *> V;
-  auto Insert = [&](std::vector<BaseCommand *> &From) {
-    V.insert(V.end(), From.begin(), From.end());
-    From.clear();
-  };
-
-  for (BaseCommand *Base : SectionCommands) {
-    if (auto *OS = dyn_cast<OutputSection>(Base)) {
-      Insert(InsertBeforeCommands[OS->Name]);
-      V.push_back(Base);
-      Insert(InsertAfterCommands[OS->Name]);
-      continue;
-    }
-    V.push_back(Base);
-  }
-
-  for (auto &Cmds : {InsertBeforeCommands, InsertAfterCommands})
-    for (const std::pair<StringRef, std::vector<BaseCommand *>> &P : Cmds)
-      if (!P.second.empty())
-        error("unable to INSERT AFTER/BEFORE " + P.first +
-              ": section not defined");
-
-  SectionCommands = std::move(V);
-}
-
-// Symbols defined in script should not be inlined by LTO. At the same time
-// we don't know their final values until late stages of link. Here we scan
-// over symbol assignment commands and create placeholder symbols if needed.
-void LinkerScript::declareSymbols() {
-  assert(!Ctx);
-  for (BaseCommand *Base : SectionCommands) {
-    if (auto *Cmd = dyn_cast<SymbolAssignment>(Base)) {
-      declareSymbol(Cmd);
-      continue;
-    }
-
-    // If the output section directive has constraints,
-    // we can't say for sure if it is going to be included or not.
-    // Skip such sections for now. Improve the checks if we ever
-    // need symbols from that sections to be declared early.
-    auto *Sec = cast<OutputSection>(Base);
-    if (Sec->Constraint != ConstraintKind::NoConstraint)
-      continue;
-    for (BaseCommand *Base2 : Sec->SectionCommands)
-      if (auto *Cmd = dyn_cast<SymbolAssignment>(Base2))
-        declareSymbol(Cmd);
-  }
-}
-
-// This function is called from assignAddresses, while we are
-// fixing the output section addresses. This function is supposed
-// to set the final value for a given symbol assignment.
-void LinkerScript::assignSymbol(SymbolAssignment *Cmd, bool InSec) {
-  if (Cmd->Name == ".") {
-    setDot(Cmd->Expression, Cmd->Location, InSec);
-    return;
-  }
-
-  if (!Cmd->Sym)
-    return;
-
-  ExprValue V = Cmd->Expression();
-  if (V.isAbsolute()) {
-    Cmd->Sym->Section = nullptr;
-    Cmd->Sym->Value = V.getValue();
-  } else {
-    Cmd->Sym->Section = V.Sec;
-    Cmd->Sym->Value = V.getSectionOffset();
-  }
-}
-
-static std::string getFilename(InputFile *File) {
-  if (!File)
-    return "";
-  if (File->ArchiveName.empty())
-    return File->getName();
-  return (File->ArchiveName + "(" + File->getName() + ")").str();
-}
-
-bool LinkerScript::shouldKeep(InputSectionBase *S) {
-  if (KeptSections.empty())
-    return false;
-  std::string Filename = getFilename(S->File);
-  for (InputSectionDescription *ID : KeptSections)
-    if (ID->FilePat.match(Filename))
-      for (SectionPattern &P : ID->SectionPatterns)
-        if (P.SectionPat.match(S->Name))
-          return true;
-  return false;
-}
-
-// A helper function for the SORT() command.
-static std::function<bool(InputSectionBase *, InputSectionBase *)>
-getComparator(SortSectionPolicy K) {
-  switch (K) {
-  case SortSectionPolicy::Alignment:
-    return [](InputSectionBase *A, InputSectionBase *B) {
-      // ">" is not a mistake. Sections with larger alignments are placed
-      // before sections with smaller alignments in order to reduce the
-      // amount of padding necessary. This is compatible with GNU.
-      return A->Alignment > B->Alignment;
-    };
-  case SortSectionPolicy::Name:
-    return [](InputSectionBase *A, InputSectionBase *B) {
-      return A->Name < B->Name;
-    };
-  case SortSectionPolicy::Priority:
-    return [](InputSectionBase *A, InputSectionBase *B) {
-      return getPriority(A->Name) < getPriority(B->Name);
-    };
-  default:
-    llvm_unreachable("unknown sort policy");
-  }
-}
-
-// A helper function for the SORT() command.
-static bool matchConstraints(ArrayRef<InputSection *> Sections,
-                             ConstraintKind Kind) {
-  if (Kind == ConstraintKind::NoConstraint)
-    return true;
-
-  bool IsRW = llvm::any_of(
-      Sections, [](InputSection *Sec) { return Sec->Flags & SHF_WRITE; });
-
-  return (IsRW && Kind == ConstraintKind::ReadWrite) ||
-         (!IsRW && Kind == ConstraintKind::ReadOnly);
-}
-
-static void sortSections(MutableArrayRef<InputSection *> Vec,
-                         SortSectionPolicy K) {
-  if (K != SortSectionPolicy::Default && K != SortSectionPolicy::None)
-    std::stable_sort(Vec.begin(), Vec.end(), getComparator(K));
-}
-
-// Sort sections as instructed by SORT-family commands and --sort-section
-// option. Because SORT-family commands can be nested at most two depth
-// (e.g. SORT_BY_NAME(SORT_BY_ALIGNMENT(.text.*))) and because the command
-// line option is respected even if a SORT command is given, the exact
-// behavior we have here is a bit complicated. Here are the rules.
-//
-// 1. If two SORT commands are given, --sort-section is ignored.
-// 2. If one SORT command is given, and if it is not SORT_NONE,
-//    --sort-section is handled as an inner SORT command.
-// 3. If one SORT command is given, and if it is SORT_NONE, don't sort.
-// 4. If no SORT command is given, sort according to --sort-section.
-static void sortInputSections(MutableArrayRef<InputSection *> Vec,
-                              const SectionPattern &Pat) {
-  if (Pat.SortOuter == SortSectionPolicy::None)
-    return;
-
-  if (Pat.SortInner == SortSectionPolicy::Default)
-    sortSections(Vec, Config->SortSection);
-  else
-    sortSections(Vec, Pat.SortInner);
-  sortSections(Vec, Pat.SortOuter);
-}
-
-// Compute and remember which sections the InputSectionDescription matches.
-std::vector<InputSection *>
-LinkerScript::computeInputSections(const InputSectionDescription *Cmd) {
-  std::vector<InputSection *> Ret;
-
-  // Collects all sections that satisfy constraints of Cmd.
-  for (const SectionPattern &Pat : Cmd->SectionPatterns) {
-    size_t SizeBefore = Ret.size();
-
-    for (InputSectionBase *Sec : InputSections) {
-      if (!Sec->Live || Sec->Assigned)
-        continue;
-
-      // For -emit-relocs we have to ignore entries like
-      //   .rela.dyn : { *(.rela.data) }
-      // which are common because they are in the default bfd script.
-      // We do not ignore SHT_REL[A] linker-synthesized sections here because
-      // want to support scripts that do custom layout for them.
-      if (auto *IS = dyn_cast<InputSection>(Sec))
-        if (IS->getRelocatedSection())
-          continue;
-
-      std::string Filename = getFilename(Sec->File);
-      if (!Cmd->FilePat.match(Filename) ||
-          Pat.ExcludedFilePat.match(Filename) ||
-          !Pat.SectionPat.match(Sec->Name))
-        continue;
-
-      // It is safe to assume that Sec is an InputSection
-      // because mergeable or EH input sections have already been
-      // handled and eliminated.
-      Ret.push_back(cast<InputSection>(Sec));
-      Sec->Assigned = true;
-    }
-
-    sortInputSections(MutableArrayRef<InputSection *>(Ret).slice(SizeBefore),
-                      Pat);
-  }
-  return Ret;
-}
-
-void LinkerScript::discard(ArrayRef<InputSection *> V) {
-  for (InputSection *S : V) {
-    if (S == In.ShStrTab || S == In.RelaDyn || S == In.RelrDyn)
-      error("discarding " + S->Name + " section is not allowed");
-
-    // You can discard .hash and .gnu.hash sections by linker scripts. Since
-    // they are synthesized sections, we need to handle them differently than
-    // other regular sections.
-    if (S == In.GnuHashTab)
-      In.GnuHashTab = nullptr;
-    if (S == In.HashTab)
-      In.HashTab = nullptr;
-
-    S->Assigned = false;
-    S->Live = false;
-    discard(S->DependentSections);
-  }
-}
-
-std::vector<InputSection *>
-LinkerScript::createInputSectionList(OutputSection &OutCmd) {
-  std::vector<InputSection *> Ret;
-
-  for (BaseCommand *Base : OutCmd.SectionCommands) {
-    if (auto *Cmd = dyn_cast<InputSectionDescription>(Base)) {
-      Cmd->Sections = computeInputSections(Cmd);
-      Ret.insert(Ret.end(), Cmd->Sections.begin(), Cmd->Sections.end());
-    }
-  }
-  return Ret;
-}
-
-void LinkerScript::processSectionCommands() {
-  // A symbol can be assigned before any section is mentioned in the linker
-  // script. In an DSO, the symbol values are addresses, so the only important
-  // section values are:
-  // * SHN_UNDEF
-  // * SHN_ABS
-  // * Any value meaning a regular section.
-  // To handle that, create a dummy aether section that fills the void before
-  // the linker scripts switches to another section. It has an index of one
-  // which will map to whatever the first actual section is.
-  Aether = make<OutputSection>("", 0, SHF_ALLOC);
-  Aether->SectionIndex = 1;
-
-  // Ctx captures the local AddressState and makes it accessible deliberately.
-  // This is needed as there are some cases where we cannot just
-  // thread the current state through to a lambda function created by the
-  // script parser.
-  auto Deleter = make_unique<AddressState>();
-  Ctx = Deleter.get();
-  Ctx->OutSec = Aether;
-
-  size_t I = 0;
-  // Add input sections to output sections.
-  for (BaseCommand *Base : SectionCommands) {
-    // Handle symbol assignments outside of any output section.
-    if (auto *Cmd = dyn_cast<SymbolAssignment>(Base)) {
-      addSymbol(Cmd);
-      continue;
-    }
-
-    if (auto *Sec = dyn_cast<OutputSection>(Base)) {
-      std::vector<InputSection *> V = createInputSectionList(*Sec);
-
-      // The output section name `/DISCARD/' is special.
-      // Any input section assigned to it is discarded.
-      if (Sec->Name == "/DISCARD/") {
-        discard(V);
-        Sec->SectionCommands.clear();
-        continue;
-      }
-
-      // This is for ONLY_IF_RO and ONLY_IF_RW. An output section directive
-      // ".foo : ONLY_IF_R[OW] { ... }" is handled only if all member input
-      // sections satisfy a given constraint. If not, a directive is handled
-      // as if it wasn't present from the beginning.
-      //
-      // Because we'll iterate over SectionCommands many more times, the easy
-      // way to "make it as if it wasn't present" is to make it empty.
-      if (!matchConstraints(V, Sec->Constraint)) {
-        for (InputSectionBase *S : V)
-          S->Assigned = false;
-        Sec->SectionCommands.clear();
-        continue;
-      }
-
-      // A directive may contain symbol definitions like this:
-      // ".foo : { ...; bar = .; }". Handle them.
-      for (BaseCommand *Base : Sec->SectionCommands)
-        if (auto *OutCmd = dyn_cast<SymbolAssignment>(Base))
-          addSymbol(OutCmd);
-
-      // Handle subalign (e.g. ".foo : SUBALIGN(32) { ... }"). If subalign
-      // is given, input sections are aligned to that value, whether the
-      // given value is larger or smaller than the original section alignment.
-      if (Sec->SubalignExpr) {
-        uint32_t Subalign = Sec->SubalignExpr().getValue();
-        for (InputSectionBase *S : V)
-          S->Alignment = Subalign;
-      }
-
-      // Add input sections to an output section.
-      for (InputSection *S : V)
-        Sec->addSection(S);
-
-      Sec->SectionIndex = I++;
-      if (Sec->Noload)
-        Sec->Type = SHT_NOBITS;
-      if (Sec->NonAlloc)
-        Sec->Flags &= ~(uint64_t)SHF_ALLOC;
-    }
-  }
-  Ctx = nullptr;
-}
-
-static OutputSection *findByName(ArrayRef<BaseCommand *> Vec,
-                                 StringRef Name) {
-  for (BaseCommand *Base : Vec)
-    if (auto *Sec = dyn_cast<OutputSection>(Base))
-      if (Sec->Name == Name)
-        return Sec;
-  return nullptr;
-}
-
-static OutputSection *createSection(InputSectionBase *IS,
-                                    StringRef OutsecName) {
-  OutputSection *Sec = Script->createOutputSection(OutsecName, "<internal>");
-  Sec->addSection(cast<InputSection>(IS));
-  return Sec;
-}
-
-static OutputSection *addInputSec(StringMap<OutputSection *> &Map,
-                                  InputSectionBase *IS, StringRef OutsecName) {
-  // Sections with SHT_GROUP or SHF_GROUP attributes reach here only when the -r
-  // option is given. A section with SHT_GROUP defines a "section group", and
-  // its members have SHF_GROUP attribute. Usually these flags have already been
-  // stripped by InputFiles.cpp as section groups are processed and uniquified.
-  // However, for the -r option, we want to pass through all section groups
-  // as-is because adding/removing members or merging them with other groups
-  // change their semantics.
-  if (IS->Type == SHT_GROUP || (IS->Flags & SHF_GROUP))
-    return createSection(IS, OutsecName);
-
-  // Imagine .zed : { *(.foo) *(.bar) } script. Both foo and bar may have
-  // relocation sections .rela.foo and .rela.bar for example. Most tools do
-  // not allow multiple REL[A] sections for output section. Hence we
-  // should combine these relocation sections into single output.
-  // We skip synthetic sections because it can be .rela.dyn/.rela.plt or any
-  // other REL[A] sections created by linker itself.
-  if (!isa<SyntheticSection>(IS) &&
-      (IS->Type == SHT_REL || IS->Type == SHT_RELA)) {
-    auto *Sec = cast<InputSection>(IS);
-    OutputSection *Out = Sec->getRelocatedSection()->getOutputSection();
-
-    if (Out->RelocationSection) {
-      Out->RelocationSection->addSection(Sec);
-      return nullptr;
-    }
-
-    Out->RelocationSection = createSection(IS, OutsecName);
-    return Out->RelocationSection;
-  }
-
-  // When control reaches here, mergeable sections have already been merged into
-  // synthetic sections. For relocatable case we want to create one output
-  // section per syntetic section so that they have a valid sh_entsize.
-  if (Config->Relocatable && (IS->Flags & SHF_MERGE))
-    return createSection(IS, OutsecName);
-
-  //  The ELF spec just says
-  // ----------------------------------------------------------------
-  // In the first phase, input sections that match in name, type and
-  // attribute flags should be concatenated into single sections.
-  // ----------------------------------------------------------------
-  //
-  // However, it is clear that at least some flags have to be ignored for
-  // section merging. At the very least SHF_GROUP and SHF_COMPRESSED have to be
-  // ignored. We should not have two output .text sections just because one was
-  // in a group and another was not for example.
-  //
-  // It also seems that wording was a late addition and didn't get the
-  // necessary scrutiny.
-  //
-  // Merging sections with different flags is expected by some users. One
-  // reason is that if one file has
-  //
-  // int *const bar __attribute__((section(".foo"))) = (int *)0;
-  //
-  // gcc with -fPIC will produce a read only .foo section. But if another
-  // file has
-  //
-  // int zed;
-  // int *const bar __attribute__((section(".foo"))) = (int *)&zed;
-  //
-  // gcc with -fPIC will produce a read write section.
-  //
-  // Last but not least, when using linker script the merge rules are forced by
-  // the script. Unfortunately, linker scripts are name based. This means that
-  // expressions like *(.foo*) can refer to multiple input sections with
-  // different flags. We cannot put them in different output sections or we
-  // would produce wrong results for
-  //
-  // start = .; *(.foo.*) end = .; *(.bar)
-  //
-  // and a mapping of .foo1 and .bar1 to one section and .foo2 and .bar2 to
-  // another. The problem is that there is no way to layout those output
-  // sections such that the .foo sections are the only thing between the start
-  // and end symbols.
-  //
-  // Given the above issues, we instead merge sections by name and error on
-  // incompatible types and flags.
-  OutputSection *&Sec = Map[OutsecName];
-  if (Sec) {
-    Sec->addSection(cast<InputSection>(IS));
-    return nullptr;
-  }
-
-  Sec = createSection(IS, OutsecName);
-  return Sec;
-}
-
-// Add sections that didn't match any sections command.
-void LinkerScript::addOrphanSections() {
-  unsigned End = SectionCommands.size();
-  StringMap<OutputSection *> Map;
-  std::vector<OutputSection *> V;
-
-  auto Add = [&](InputSectionBase *S) {
-    if (!S->Live || S->Parent)
-      return;
-
-    StringRef Name = getOutputSectionName(S);
-
-    if (Config->OrphanHandling == OrphanHandlingPolicy::Error)
-      error(toString(S) + " is being placed in '" + Name + "'");
-    else if (Config->OrphanHandling == OrphanHandlingPolicy::Warn)
-      warn(toString(S) + " is being placed in '" + Name + "'");
-
-    if (OutputSection *Sec =
-            findByName(makeArrayRef(SectionCommands).slice(0, End), Name)) {
-      Sec->addSection(cast<InputSection>(S));
-      return;
-    }
-
-    if (OutputSection *OS = addInputSec(Map, S, Name))
-      V.push_back(OS);
-    assert(S->getOutputSection()->SectionIndex == UINT32_MAX);
-  };
-
-  // For futher --emit-reloc handling code we need target output section
-  // to be created before we create relocation output section, so we want
-  // to create target sections first. We do not want priority handling
-  // for synthetic sections because them are special.
-  for (InputSectionBase *IS : InputSections) {
-    if (auto *Sec = dyn_cast<InputSection>(IS))
-      if (InputSectionBase *Rel = Sec->getRelocatedSection())
-        if (auto *RelIS = dyn_cast_or_null<InputSectionBase>(Rel->Parent))
-          Add(RelIS);
-    Add(IS);
-  }
-
-  // If no SECTIONS command was given, we should insert sections commands
-  // before others, so that we can handle scripts which refers them,
-  // for example: "foo = ABSOLUTE(ADDR(.text)));".
-  // When SECTIONS command is present we just add all orphans to the end.
-  if (HasSectionsCommand)
-    SectionCommands.insert(SectionCommands.end(), V.begin(), V.end());
-  else
-    SectionCommands.insert(SectionCommands.begin(), V.begin(), V.end());
-}
-
-uint64_t LinkerScript::advance(uint64_t Size, unsigned Alignment) {
-  bool IsTbss =
-      (Ctx->OutSec->Flags & SHF_TLS) && Ctx->OutSec->Type == SHT_NOBITS;
-  uint64_t Start = IsTbss ? Dot + Ctx->ThreadBssOffset : Dot;
-  Start = alignTo(Start, Alignment);
-  uint64_t End = Start + Size;
-
-  if (IsTbss)
-    Ctx->ThreadBssOffset = End - Dot;
-  else
-    Dot = End;
-  return End;
-}
-
-void LinkerScript::output(InputSection *S) {
-  assert(Ctx->OutSec == S->getParent());
-  uint64_t Before = advance(0, 1);
-  uint64_t Pos = advance(S->getSize(), S->Alignment);
-  S->OutSecOff = Pos - S->getSize() - Ctx->OutSec->Addr;
-
-  // Update output section size after adding each section. This is so that
-  // SIZEOF works correctly in the case below:
-  // .foo { *(.aaa) a = SIZEOF(.foo); *(.bbb) }
-  expandOutputSection(Pos - Before);
-}
-
-void LinkerScript::switchTo(OutputSection *Sec) {
-  Ctx->OutSec = Sec;
-
-  uint64_t Before = advance(0, 1);
-  Ctx->OutSec->Addr = advance(0, Ctx->OutSec->Alignment);
-  expandMemoryRegions(Ctx->OutSec->Addr - Before);
-}
-
-// This function searches for a memory region to place the given output
-// section in. If found, a pointer to the appropriate memory region is
-// returned. Otherwise, a nullptr is returned.
-MemoryRegion *LinkerScript::findMemoryRegion(OutputSection *Sec) {
-  // If a memory region name was specified in the output section command,
-  // then try to find that region first.
-  if (!Sec->MemoryRegionName.empty()) {
-    if (MemoryRegion *M = MemoryRegions.lookup(Sec->MemoryRegionName))
-      return M;
-    error("memory region '" + Sec->MemoryRegionName + "' not declared");
-    return nullptr;
-  }
-
-  // If at least one memory region is defined, all sections must
-  // belong to some memory region. Otherwise, we don't need to do
-  // anything for memory regions.
-  if (MemoryRegions.empty())
-    return nullptr;
-
-  // See if a region can be found by matching section flags.
-  for (auto &Pair : MemoryRegions) {
-    MemoryRegion *M = Pair.second;
-    if ((M->Flags & Sec->Flags) && (M->NegFlags & Sec->Flags) == 0)
-      return M;
-  }
-
-  // Otherwise, no suitable region was found.
-  if (Sec->Flags & SHF_ALLOC)
-    error("no memory region specified for section '" + Sec->Name + "'");
-  return nullptr;
-}
-
-static OutputSection *findFirstSection(PhdrEntry *Load) {
-  for (OutputSection *Sec : OutputSections)
-    if (Sec->PtLoad == Load)
-      return Sec;
-  return nullptr;
-}
-
-// This function assigns offsets to input sections and an output section
-// for a single sections command (e.g. ".text { *(.text); }").
-void LinkerScript::assignOffsets(OutputSection *Sec) {
-  if (!(Sec->Flags & SHF_ALLOC))
-    Dot = 0;
-  else if (Sec->AddrExpr)
-    setDot(Sec->AddrExpr, Sec->Location, false);
-
-  Ctx->MemRegion = Sec->MemRegion;
-  Ctx->LMARegion = Sec->LMARegion;
-  if (Ctx->MemRegion)
-    Dot = Ctx->MemRegion->CurPos;
-
-  if (Sec->LMAExpr)
-    Ctx->LMAOffset = Sec->LMAExpr().getValue() - Dot;
-
-  if (MemoryRegion *MR = Sec->LMARegion)
-    Ctx->LMAOffset = MR->CurPos - Dot;
-
-  switchTo(Sec);
-
-  // If neither AT nor AT> is specified for an allocatable section, the linker
-  // will set the LMA such that the difference between VMA and LMA for the
-  // section is the same as the preceding output section in the same region
-  // https://sourceware.org/binutils/docs-2.20/ld/Output-Section-LMA.html
-  // This, however, should only be done by the first "non-header" section
-  // in the segment.
-  if (PhdrEntry *L = Ctx->OutSec->PtLoad)
-    if (Sec == findFirstSection(L))
-      L->LMAOffset = Ctx->LMAOffset;
-
-  // We can call this method multiple times during the creation of
-  // thunks and want to start over calculation each time.
-  Sec->Size = 0;
-
-  // We visited SectionsCommands from processSectionCommands to
-  // layout sections. Now, we visit SectionsCommands again to fix
-  // section offsets.
-  for (BaseCommand *Base : Sec->SectionCommands) {
-    // This handles the assignments to symbol or to the dot.
-    if (auto *Cmd = dyn_cast<SymbolAssignment>(Base)) {
-      Cmd->Addr = Dot;
-      assignSymbol(Cmd, true);
-      Cmd->Size = Dot - Cmd->Addr;
-      continue;
-    }
-
-    // Handle BYTE(), SHORT(), LONG(), or QUAD().
-    if (auto *Cmd = dyn_cast<ByteCommand>(Base)) {
-      Cmd->Offset = Dot - Ctx->OutSec->Addr;
-      Dot += Cmd->Size;
-      expandOutputSection(Cmd->Size);
-      continue;
-    }
-
-    // Handle a single input section description command.
-    // It calculates and assigns the offsets for each section and also
-    // updates the output section size.
-    for (InputSection *Sec : cast<InputSectionDescription>(Base)->Sections)
-      output(Sec);
-  }
-}
-
-static bool isDiscardable(OutputSection &Sec) {
-  // We do not remove empty sections that are explicitly
-  // assigned to any segment.
-  if (!Sec.Phdrs.empty())
-    return false;
-
-  // We do not want to remove sections that reference symbols in address and
-  // other expressions. We add script symbols as undefined, and want to ensure
-  // all of them are defined in the output, hence have to keep them.
-  if (Sec.ExpressionsUseSymbols)
-    return false;
-
-  for (BaseCommand *Base : Sec.SectionCommands) {
-    if (auto Cmd = dyn_cast<SymbolAssignment>(Base))
-      // Don't create empty output sections just for unreferenced PROVIDE
-      // symbols.
-      if (Cmd->Name != "." && !Cmd->Sym)
-        continue;
-
-    if (!isa<InputSectionDescription>(*Base))
-      return false;
-  }
-  return true;
-}
-
-void LinkerScript::adjustSectionsBeforeSorting() {
-  // If the output section contains only symbol assignments, create a
-  // corresponding output section. The issue is what to do with linker script
-  // like ".foo : { symbol = 42; }". One option would be to convert it to
-  // "symbol = 42;". That is, move the symbol out of the empty section
-  // description. That seems to be what bfd does for this simple case. The
-  // problem is that this is not completely general. bfd will give up and
-  // create a dummy section too if there is a ". = . + 1" inside the section
-  // for example.
-  // Given that we want to create the section, we have to worry what impact
-  // it will have on the link. For example, if we just create a section with
-  // 0 for flags, it would change which PT_LOADs are created.
-  // We could remember that particular section is dummy and ignore it in
-  // other parts of the linker, but unfortunately there are quite a few places
-  // that would need to change:
-  //   * The program header creation.
-  //   * The orphan section placement.
-  //   * The address assignment.
-  // The other option is to pick flags that minimize the impact the section
-  // will have on the rest of the linker. That is why we copy the flags from
-  // the previous sections. Only a few flags are needed to keep the impact low.
-  uint64_t Flags = SHF_ALLOC;
-
-  for (BaseCommand *&Cmd : SectionCommands) {
-    auto *Sec = dyn_cast<OutputSection>(Cmd);
-    if (!Sec)
-      continue;
-
-    // Handle align (e.g. ".foo : ALIGN(16) { ... }").
-    if (Sec->AlignExpr)
-      Sec->Alignment =
-          std::max<uint32_t>(Sec->Alignment, Sec->AlignExpr().getValue());
-
-    // A live output section means that some input section was added to it. It
-    // might have been removed (if it was empty synthetic section), but we at
-    // least know the flags.
-    if (Sec->Live)
-      Flags = Sec->Flags;
-
-    // We do not want to keep any special flags for output section
-    // in case it is empty.
-    bool IsEmpty = getInputSections(Sec).empty();
-    if (IsEmpty)
-      Sec->Flags = Flags & (SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR);
-
-    if (IsEmpty && isDiscardable(*Sec)) {
-      Sec->Live = false;
-      Cmd = nullptr;
-    }
-  }
-
-  // It is common practice to use very generic linker scripts. So for any
-  // given run some of the output sections in the script will be empty.
-  // We could create corresponding empty output sections, but that would
-  // clutter the output.
-  // We instead remove trivially empty sections. The bfd linker seems even
-  // more aggressive at removing them.
-  llvm::erase_if(SectionCommands, [&](BaseCommand *Base) { return !Base; });
-}
-
-void LinkerScript::adjustSectionsAfterSorting() {
-  // Try and find an appropriate memory region to assign offsets in.
-  for (BaseCommand *Base : SectionCommands) {
-    if (auto *Sec = dyn_cast<OutputSection>(Base)) {
-      if (!Sec->LMARegionName.empty()) {
-        if (MemoryRegion *M = MemoryRegions.lookup(Sec->LMARegionName))
-          Sec->LMARegion = M;
-        else
-          error("memory region '" + Sec->LMARegionName + "' not declared");
-      }
-      Sec->MemRegion = findMemoryRegion(Sec);
-    }
-  }
-
-  // If output section command doesn't specify any segments,
-  // and we haven't previously assigned any section to segment,
-  // then we simply assign section to the very first load segment.
-  // Below is an example of such linker script:
-  // PHDRS { seg PT_LOAD; }
-  // SECTIONS { .aaa : { *(.aaa) } }
-  std::vector<StringRef> DefPhdrs;
-  auto FirstPtLoad = llvm::find_if(PhdrsCommands, [](const PhdrsCommand &Cmd) {
-    return Cmd.Type == PT_LOAD;
-  });
-  if (FirstPtLoad != PhdrsCommands.end())
-    DefPhdrs.push_back(FirstPtLoad->Name);
-
-  // Walk the commands and propagate the program headers to commands that don't
-  // explicitly specify them.
-  for (BaseCommand *Base : SectionCommands) {
-    auto *Sec = dyn_cast<OutputSection>(Base);
-    if (!Sec)
-      continue;
-
-    if (Sec->Phdrs.empty()) {
-      // To match the bfd linker script behaviour, only propagate program
-      // headers to sections that are allocated.
-      if (Sec->Flags & SHF_ALLOC)
-        Sec->Phdrs = DefPhdrs;
-    } else {
-      DefPhdrs = Sec->Phdrs;
-    }
-  }
-}
-
-static uint64_t computeBase(uint64_t Min, bool AllocateHeaders) {
-  // If there is no SECTIONS or if the linkerscript is explicit about program
-  // headers, do our best to allocate them.
-  if (!Script->HasSectionsCommand || AllocateHeaders)
-    return 0;
-  // Otherwise only allocate program headers if that would not add a page.
-  return alignDown(Min, Config->MaxPageSize);
-}
-
-// Try to find an address for the file and program headers output sections,
-// which were unconditionally added to the first PT_LOAD segment earlier.
-//
-// When using the default layout, we check if the headers fit below the first
-// allocated section. When using a linker script, we also check if the headers
-// are covered by the output section. This allows omitting the headers by not
-// leaving enough space for them in the linker script; this pattern is common
-// in embedded systems.
-//
-// If there isn't enough space for these sections, we'll remove them from the
-// PT_LOAD segment, and we'll also remove the PT_PHDR segment.
-void LinkerScript::allocateHeaders(std::vector<PhdrEntry *> &Phdrs) {
-  uint64_t Min = std::numeric_limits<uint64_t>::max();
-  for (OutputSection *Sec : OutputSections)
-    if (Sec->Flags & SHF_ALLOC)
-      Min = std::min<uint64_t>(Min, Sec->Addr);
-
-  auto It = llvm::find_if(
-      Phdrs, [](const PhdrEntry *E) { return E->p_type == PT_LOAD; });
-  if (It == Phdrs.end())
-    return;
-  PhdrEntry *FirstPTLoad = *It;
-
-  bool HasExplicitHeaders =
-      llvm::any_of(PhdrsCommands, [](const PhdrsCommand &Cmd) {
-        return Cmd.HasPhdrs || Cmd.HasFilehdr;
-      });
-  uint64_t HeaderSize = getHeaderSize();
-  if (HeaderSize <= Min - computeBase(Min, HasExplicitHeaders)) {
-    Min = alignDown(Min - HeaderSize, Config->MaxPageSize);
-    Out::ElfHeader->Addr = Min;
-    Out::ProgramHeaders->Addr = Min + Out::ElfHeader->Size;
-    return;
-  }
-
-  // Error if we were explicitly asked to allocate headers.
-  if (HasExplicitHeaders)
-    error("could not allocate headers");
-
-  Out::ElfHeader->PtLoad = nullptr;
-  Out::ProgramHeaders->PtLoad = nullptr;
-  FirstPTLoad->FirstSec = findFirstSection(FirstPTLoad);
-
-  llvm::erase_if(Phdrs,
-                 [](const PhdrEntry *E) { return E->p_type == PT_PHDR; });
-}
-
-LinkerScript::AddressState::AddressState() {
-  for (auto &MRI : Script->MemoryRegions) {
-    MemoryRegion *MR = MRI.second;
-    MR->CurPos = MR->Origin;
-  }
-}
-
-static uint64_t getInitialDot() {
-  // By default linker scripts use an initial value of 0 for '.',
-  // but prefer -image-base if set.
-  if (Script->HasSectionsCommand)
-    return Config->ImageBase ? *Config->ImageBase : 0;
-
-  uint64_t StartAddr = UINT64_MAX;
-  // The Sections with -T<section> have been sorted in order of ascending
-  // address. We must lower StartAddr if the lowest -T<section address> as
-  // calls to setDot() must be monotonically increasing.
-  for (auto &KV : Config->SectionStartMap)
-    StartAddr = std::min(StartAddr, KV.second);
-  return std::min(StartAddr, Target->getImageBase() + elf::getHeaderSize());
-}
-
-// Here we assign addresses as instructed by linker script SECTIONS
-// sub-commands. Doing that allows us to use final VA values, so here
-// we also handle rest commands like symbol assignments and ASSERTs.
-void LinkerScript::assignAddresses() {
-  Dot = getInitialDot();
-
-  auto Deleter = make_unique<AddressState>();
-  Ctx = Deleter.get();
-  ErrorOnMissingSection = true;
-  switchTo(Aether);
-
-  for (BaseCommand *Base : SectionCommands) {
-    if (auto *Cmd = dyn_cast<SymbolAssignment>(Base)) {
-      Cmd->Addr = Dot;
-      assignSymbol(Cmd, false);
-      Cmd->Size = Dot - Cmd->Addr;
-      continue;
-    }
-    assignOffsets(cast<OutputSection>(Base));
-  }
-  Ctx = nullptr;
-}
-
-// Creates program headers as instructed by PHDRS linker script command.
-std::vector<PhdrEntry *> LinkerScript::createPhdrs() {
-  std::vector<PhdrEntry *> 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 : PhdrsCommands) {
-    PhdrEntry *Phdr = make<PhdrEntry>(Cmd.Type, Cmd.Flags ? *Cmd.Flags : PF_R);
-
-    if (Cmd.HasFilehdr)
-      Phdr->add(Out::ElfHeader);
-    if (Cmd.HasPhdrs)
-      Phdr->add(Out::ProgramHeaders);
-
-    if (Cmd.LMAExpr) {
-      Phdr->p_paddr = Cmd.LMAExpr().getValue();
-      Phdr->HasLMA = true;
-    }
-    Ret.push_back(Phdr);
-  }
-
-  // Add output sections to program headers.
-  for (OutputSection *Sec : OutputSections) {
-    // Assign headers specified by linker script
-    for (size_t Id : getPhdrIndices(Sec)) {
-      Ret[Id]->add(Sec);
-      if (!PhdrsCommands[Id].Flags.hasValue())
-        Ret[Id]->p_flags |= Sec->getPhdrFlags();
-    }
-  }
-  return Ret;
-}
-
-// Returns true if we should emit an .interp section.
-//
-// We usually do. But if PHDRS commands are given, and
-// no PT_INTERP is there, there's no place to emit an
-// .interp, so we don't do that in that case.
-bool LinkerScript::needsInterpSection() {
-  if (PhdrsCommands.empty())
-    return true;
-  for (PhdrsCommand &Cmd : PhdrsCommands)
-    if (Cmd.Type == PT_INTERP)
-      return true;
-  return false;
-}
-
-ExprValue LinkerScript::getSymbolValue(StringRef Name, const Twine &Loc) {
-  if (Name == ".") {
-    if (Ctx)
-      return {Ctx->OutSec, false, Dot - Ctx->OutSec->Addr, Loc};
-    error(Loc + ": unable to get location counter value");
-    return 0;
-  }
-
-  if (Symbol *Sym = Symtab->find(Name)) {
-    if (auto *DS = dyn_cast<Defined>(Sym))
-      return {DS->Section, false, DS->Value, Loc};
-    if (isa<SharedSymbol>(Sym))
-      if (!ErrorOnMissingSection)
-        return {nullptr, false, 0, Loc};
-  }
-
-  error(Loc + ": symbol not found: " + Name);
-  return 0;
-}
-
-// Returns the index of the segment named Name.
-static Optional<size_t> getPhdrIndex(ArrayRef<PhdrsCommand> Vec,
-                                     StringRef Name) {
-  for (size_t I = 0; I < Vec.size(); ++I)
-    if (Vec[I].Name == Name)
-      return I;
-  return None;
-}
-
-// Returns indices of ELF headers containing specific section. Each index is a
-// zero based number of ELF header listed within PHDRS {} script block.
-std::vector<size_t> LinkerScript::getPhdrIndices(OutputSection *Cmd) {
-  std::vector<size_t> Ret;
-
-  for (StringRef S : Cmd->Phdrs) {
-    if (Optional<size_t> Idx = getPhdrIndex(PhdrsCommands, S))
-      Ret.push_back(*Idx);
-    else if (S != "NONE")
-      error(Cmd->Location + ": section header '" + S +
-            "' is not listed in PHDRS");
-  }
-  return Ret;
-}