Revert r341342: Dwarf .debug section compression support (zlib, zlib-gnu).

Also reverts follow-up commits r341343 and r341344.

The primary commit continues to break some build bots even after the
fixes in r341343 for UBSan issues:
http://lab.llvm.org:8011/builders/clang-cmake-aarch64-full/builds/5823

It is also failing for me locally (linux, x86-64).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341360 91177308-0d34-0410-b5e6-96231b3b80d8

test/tools/llvm-objcopy/Inputs/compress-debug-sections.yaml

@@ -1,21 +0,0 @@
---- !ELF
-FileHeader:
-  Class:           ELFCLASS64
-  Data:            ELFDATA2LSB
-  Type:            ET_REL
-  Machine:         EM_X86_64
-Sections:
-  - Name:            .debug_foo
-    Type:            SHT_PROGBITS
-    Content:         0000000000000000
-  - Name:            .notdebug_foo
-    Type:            SHT_PROGBITS
-    Content:         0000000000000000
-  - Name:            .rela.debug_foo
-    Type:            SHT_RELA
-    Info:            .debug_foo
-    Relocations:
-      - Offset:          0x1
-        Symbol:          .debug_foo
-        Type:            R_X86_64_32
-...

test/tools/llvm-objcopy/compress-debug-sections-default-gnu.test

@@ -1,9 +0,0 @@
-# REQUIRES: zlib
-
-# RUN: yaml2obj %p/Inputs/compress-debug-sections.yaml -o %t.o
-# RUN: llvm-objcopy --compress-debug-sections --compress-debug-sections=zlib-gnu %t.o %t-compressed.o
-# RUN: llvm-objdump -s %t-compressed.o | FileCheck %s
-
-# CHECK: .zdebug_foo:
-# CHECK: ZLIB
-

test/tools/llvm-objcopy/compress-debug-sections-default.test

@@ -1,13 +0,0 @@
-# REQUIRES: zlib
-
-# RUN: yaml2obj %p/Inputs/compress-debug-sections.yaml -o %t.o
-# RUN: llvm-objcopy --compress-debug-sections %t.o %t-compressed.o
-# RUN: llvm-readobj -s %t-compressed.o | FileCheck %s
-
-# CHECK: Name: .debug_foo
-# CHECK-NEXT: Type: SHT_PROGBITS
-# CHECK-NEXT: Flags [
-# CHECK-NEXT: SHF_COMPRESSED
-# CHECK-NEXT: ]
-# CHECK-NOT: Name: .debug_foo
-

test/tools/llvm-objcopy/compress-debug-sections-invalid-format.test

@@ -1,5 +0,0 @@
-# RUN: yaml2obj %p/Inputs/compress-debug-sections.yaml -o %t.o
-# RUN: not llvm-objcopy --compress-debug-sections=zlib-fake %t.o 2>&1 | FileCheck %s
-
-# CHECK: Invalid or unsupported --compress-debug-sections format: zlib-fake.
-

test/tools/llvm-objcopy/compress-debug-sections-zlib-gnu.test

@@ -1,49 +0,0 @@
-# REQUIRES: zlib
-
-# RUN: yaml2obj %p/Inputs/compress-debug-sections.yaml -o %t.o
-# RUN: llvm-objcopy --compress-debug-sections=zlib-gnu %t.o %t-compressed.o
-
-# RUN: llvm-objdump -s %t.o -section=.debug_foo | FileCheck %s
-# RUN: llvm-objdump -s %t-compressed.o | FileCheck %s --check-prefix=CHECK-COMPRESSED
-# RUN: llvm-readobj -relocations -s %t-compressed.o | FileCheck %s --check-prefix=CHECK-FLAGS
-
-# CHECK: .debug_foo:
-
-# CHECK-COMPRESSED: .zdebug_foo:
-# CHECK-COMPRESSED: ZLIB
-# CHECK-COMPRESSED: .notdebug_foo:
-
-# CHECK-FLAGS-NOT: Name: .debug_foo
-# CHECK-FLAGS: Index: 1
-# CHECK-FLAGS-NEXT: Name: .zdebug_foo
-# CHECK-FLAGS-NEXT: Type: SHT_PROGBITS
-# CHECK-FLAGS-NEXT: Flags [
-# CHECK-FLAGS-NEXT: ]
-# CHECK-FLAGS-NEXT: Address:
-# CHECK-FLAGS-NEXT: Offset:
-# CHECK-FLAGS-NEXT: Size: 23
-
-# CHECK-FLAGS: Name: .notdebug_foo
-# CHECK-FLAGS-NEXT: Type: SHT_PROGBITS
-# CHECK-FLAGS-NEXT: Flags [
-# CHECK-FLAGS-NEXT: ]
-# CHECK-FLAGS-NEXT: Address:
-# CHECK-FLAGS-NEXT: Offset:
-# CHECK-FLAGS-NEXT: Size: 8
-
-# CHECK-FLAGS: Name: .rela.debug_foo
-# CHECK-FLAGS-NEXT: Type: SHT_RELA
-# CHECK-FLAGS-NEXT: Flags [
-# CHECK-FLAGS-NEXT: ]
-# CHECK-FLAGS-NEXT: Address:
-# CHECK-FLAGS-NEXT: Offset:
-# CHECK-FLAGS-NEXT: Size:
-# CHECK-FLAGS-NEXT: Link:
-# CHECK-FLAGS-NEXT: Info: 1
-
-# CHECK-FLAGS: Relocations [
-# CHECK-FLAGS-NEXT:   .rela.debug_foo {
-# CHECK-FLAGS-NEXT:     0x1 R_X86_64_32 - 0x0
-# CHECK-FLAGS-NEXT:   }
-# CHECK-FLAGS-NEXT: ]
-

test/tools/llvm-objcopy/compress-debug-sections-zlib.test

@@ -1,49 +0,0 @@
-# REQUIRES: zlib
-
-# RUN: yaml2obj %p/Inputs/compress-debug-sections.yaml -o %t.o
-# RUN: llvm-objcopy --compress-debug-sections=zlib %t.o %t-compressed.o
-
-# RUN: llvm-objdump -s %t.o -section=.debug_foo | FileCheck %s
-# RUN: llvm-objdump -s %t-compressed.o | FileCheck %s --check-prefix=CHECK-COMPRESSED
-# RUN: llvm-readobj -relocations -s %t-compressed.o | FileCheck %s --check-prefix=CHECK-FLAGS
-
-# CHECK: .debug_foo:
-
-# CHECK-COMPRESSED: .debug_foo:
-# CHECK-COMPRESSED: .notdebug_foo:
-
-# CHECK-FLAGS: Index: 1
-# CHECK-FLAGS-NEXT: Name: .debug_foo
-# CHECK-FLAGS-NEXT: Type: SHT_PROGBITS
-# CHECK-FLAGS-NEXT: Flags [
-# CHECK-FLAGS-NEXT: SHF_COMPRESSED
-# CHECK-FLAGS-NEXT: ]
-# CHECK-FLAGS-NEXT: Address:
-# CHECK-FLAGS-NEXT: Offset:
-# CHECK-FLAGS-NEXT: Size: 35
-# CHECK-FLAGS-NOT: Name: .debug_foo
-
-# CHECK-FLAGS: Name: .notdebug_foo
-# CHECK-FLAGS-NEXT: Type: SHT_PROGBITS
-# CHECK-FLAGS-NEXT: Flags [
-# CHECK-FLAGS-NEXT: ]
-# CHECK-FLAGS-NEXT: Address:
-# CHECK-FLAGS-NEXT: Offset:
-# CHECK-FLAGS-NEXT: Size: 8
-
-# CHECK-FLAGS: Name: .rela.debug_foo
-# CHECK-FLAGS-NEXT: Type: SHT_RELA
-# CHECK-FLAGS-NEXT: Flags [
-# CHECK-FLAGS-NEXT: ]
-# CHECK-FLAGS-NEXT: Address:
-# CHECK-FLAGS-NEXT: Offset:
-# CHECK-FLAGS-NEXT: Size:
-# CHECK-FLAGS-NEXT: Link:
-# CHECK-FLAGS-NEXT: Info: 1
-
-# CHECK-FLAGS: Relocations [
-# CHECK-FLAGS-NEXT:   .rela.debug_foo {
-# CHECK-FLAGS-NEXT:     0x1 R_X86_64_32 - 0x0
-# CHECK-FLAGS-NEXT:   }
-# CHECK-FLAGS-NEXT: ]
-

tools/llvm-objcopy/ObjcopyOpts.td

@@ -17,12 +17,6 @@ def I : JoinedOrSeparate<[ "-" ], "I">, Alias<input_target>;
 defm output_target : Eq<"output-target">,
                      HelpText<"Format of the output file">,
                      Values<"binary">;
-def compress_debug_sections : Flag<["--", "-"], "compress-debug-sections">;
-def compress_debug_sections_eq : Joined<["--", "-"], "compress-debug-sections=">,
-                                 MetaVarName<"[ zlib | zlib-gnu ]">,
-                                 HelpText<"Compress DWARF debug sections using "
-                                          "specified style. Supported styles: "
-                                          "'zlib-gnu' and 'zlib'">;
 def O : JoinedOrSeparate<["-"], "O">,
         Alias<output_target>;
 defm split_dwo : Eq<"split-dwo">,

tools/llvm-objcopy/Object.cpp

@@ -15,9 +15,7 @@
 #include "llvm/ADT/Twine.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/BinaryFormat/ELF.h"
-#include "llvm/MC/MCTargetOptions.h"
 #include "llvm/Object/ELFObjectFile.h"
-#include "llvm/Support/Compression.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileOutputBuffer.h"
 #include "llvm/Support/Path.h"
@@ -140,65 +138,6 @@ void OwnedDataSection::accept(SectionVisitor &Visitor) const {
   Visitor.visit(*this);
 }
 
-void BinarySectionWriter::visit(const CompressedSection &Sec) {
-  error("Cannot write compressed section '" + Sec.Name + "' ");
-}
-
-template <class ELFT>
-void ELFSectionWriter<ELFT>::visit(const CompressedSection &Sec) {
-  uint8_t *Buf = Out.getBufferStart();
-  Buf += Sec.Offset;
-
-  if (Sec.CompressionType == DebugCompressionType::GNU) {
-    ArrayRef<uint8_t> Magic = {'Z', 'L', 'I', 'B'};
-    std::copy(Magic.begin(), Magic.end(), Buf);
-    Buf += Magic.size();
-    const uint64_t DecompressedSize =
-        support::endian::read64be(&Sec.DecompressedSize);
-    memcpy(Buf, &DecompressedSize, sizeof(DecompressedSize));
-    Buf += sizeof(DecompressedSize);
-  } else {
-    auto Chdr = reinterpret_cast<Elf_Chdr_Impl<ELFT> *>(Buf);
-    Chdr->ch_type = ELF::ELFCOMPRESS_ZLIB;
-    Chdr->ch_size = Sec.DecompressedSize;
-    Chdr->ch_addralign = Sec.DecompressedAlign;
-    Buf += sizeof(*Chdr);
-  }
-
-  std::copy(Sec.CompressedData.begin(), Sec.CompressedData.end(), Buf);
-}
-
-CompressedSection::CompressedSection(const SectionBase &Sec,
-                                     DebugCompressionType CompressionType)
-    : SectionBase(Sec), CompressionType(CompressionType),
-      DecompressedSize(Sec.OriginalData.size()), DecompressedAlign(Sec.Align) {
-
-  if (Error E = zlib::compress(
-          StringRef(reinterpret_cast<const char *>(OriginalData.data()),
-                    OriginalData.size()),
-          CompressedData))
-    reportError(Name, std::move(E));
-
-  size_t ChdrSize;
-  if (CompressionType == DebugCompressionType::GNU) {
-    Name = ".z" + Sec.Name.substr(1);
-    ChdrSize = sizeof("ZLIB") - 1 + sizeof(uint64_t);
-  } else {
-    Flags |= ELF::SHF_COMPRESSED;
-    ChdrSize =
-        std::max(std::max(sizeof(object::Elf_Chdr_Impl<object::ELF64LE>),
-                          sizeof(object::Elf_Chdr_Impl<object::ELF64BE>)),
-                 std::max(sizeof(object::Elf_Chdr_Impl<object::ELF32LE>),
-                          sizeof(object::Elf_Chdr_Impl<object::ELF32BE>)));
-  }
-  Size = ChdrSize + CompressedData.size();
-  Align = 8;
-}
-
-void CompressedSection::accept(SectionVisitor &Visitor) const {
-  Visitor.visit(*this);
-}
-
 void StringTableSection::addString(StringRef Name) {
   StrTabBuilder.add(Name);
   Size = StrTabBuilder.getSize();

tools/llvm-objcopy/Object.h

@@ -26,7 +26,6 @@
 #include <vector>
 
 namespace llvm {
-enum class DebugCompressionType;
 namespace objcopy {
 
 class Buffer;
@@ -40,7 +39,6 @@ class DynamicRelocationSection;
 class GnuDebugLinkSection;
 class GroupSection;
 class SectionIndexSection;
-class CompressedSection;
 class Segment;
 class Object;
 struct Symbol;
@@ -88,7 +86,6 @@ public:
   virtual void visit(const GnuDebugLinkSection &Sec) = 0;
   virtual void visit(const GroupSection &Sec) = 0;
   virtual void visit(const SectionIndexSection &Sec) = 0;
-  virtual void visit(const CompressedSection &Sec) = 0;
 };
 
 class SectionWriter : public SectionVisitor {
@@ -107,7 +104,6 @@ public:
   virtual void visit(const GnuDebugLinkSection &Sec) override = 0;
   virtual void visit(const GroupSection &Sec) override = 0;
   virtual void visit(const SectionIndexSection &Sec) override = 0;
-  virtual void visit(const CompressedSection &Sec) override = 0;
 
   explicit SectionWriter(Buffer &Buf) : Out(Buf) {}
 };
@@ -126,7 +122,6 @@ public:
   void visit(const GnuDebugLinkSection &Sec) override;
   void visit(const GroupSection &Sec) override;
   void visit(const SectionIndexSection &Sec) override;
-  void visit(const CompressedSection &Sec) override;
 
   explicit ELFSectionWriter(Buffer &Buf) : SectionWriter(Buf) {}
 };
@@ -144,7 +139,6 @@ public:
   void visit(const GnuDebugLinkSection &Sec) override;
   void visit(const GroupSection &Sec) override;
   void visit(const SectionIndexSection &Sec) override;
-  void visit(const CompressedSection &Sec) override;
 
   explicit BinarySectionWriter(Buffer &Buf) : SectionWriter(Buf) {}
 };
@@ -252,7 +246,7 @@ public:
 
 class SectionBase {
 public:
-  std::string Name;
+  StringRef Name;
   Segment *ParentSegment = nullptr;
   uint64_t HeaderOffset;
   uint64_t OriginalOffset = std::numeric_limits<uint64_t>::max();
@@ -271,9 +265,6 @@ public:
   uint64_t Type = ELF::SHT_NULL;
   ArrayRef<uint8_t> OriginalData;
 
-  SectionBase() = default;
-  SectionBase(const SectionBase &) = default;
-
   virtual ~SectionBase() = default;
 
   virtual void initialize(SectionTableRef SecTable);
@@ -350,7 +341,7 @@ class OwnedDataSection : public SectionBase {
 public:
   OwnedDataSection(StringRef SecName, ArrayRef<uint8_t> Data)
       : Data(std::begin(Data), std::end(Data)) {
-    Name = SecName.str();
+    Name = SecName;
     Type = ELF::SHT_PROGBITS;
     Size = Data.size();
     OriginalOffset = std::numeric_limits<uint64_t>::max();
@@ -359,20 +350,6 @@ public:
   void accept(SectionVisitor &Sec) const override;
 };
 
-class CompressedSection : public SectionBase {
-  MAKE_SEC_WRITER_FRIEND
-
-  DebugCompressionType CompressionType;
-  uint64_t DecompressedSize;
-  uint64_t DecompressedAlign;
-  SmallVector<char, 128> CompressedData;
-
-public:
-  CompressedSection(const SectionBase &Sec,
-                    DebugCompressionType CompressionType);
-  void accept(SectionVisitor &Visitor) const override;
-};
-
 // There are two types of string tables that can exist, dynamic and not dynamic.
 // In the dynamic case the string table is allocated. Changing a dynamic string
 // table would mean altering virtual addresses and thus the memory image. So

tools/llvm-objcopy/llvm-objcopy.cpp

@@ -17,7 +17,6 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/BinaryFormat/ELF.h"
-#include "llvm/MC/MCTargetOptions.h"
 #include "llvm/Object/Archive.h"
 #include "llvm/Object/ArchiveWriter.h"
 #include "llvm/Object/Binary.h"
@@ -176,7 +175,6 @@ struct CopyConfig {
   bool StripSections = false;
   bool StripUnneeded = false;
   bool Weaken = false;
-  DebugCompressionType CompressionType = DebugCompressionType::None;
 };
 
 using SectionPred = std::function<bool(const SectionBase &Sec)>;
@@ -292,12 +290,12 @@ static SectionRename parseRenameSectionValue(StringRef FlagValue) {
 }
 
 static bool isDebugSection(const SectionBase &Sec) {
-  return StringRef(Sec.Name).startswith(".debug") ||
-         StringRef(Sec.Name).startswith(".zdebug") || Sec.Name == ".gdb_index";
+  return Sec.Name.startswith(".debug") || Sec.Name.startswith(".zdebug") ||
+         Sec.Name == ".gdb_index";
 }
 
 static bool isDWOSection(const SectionBase &Sec) {
-  return StringRef(Sec.Name).endswith(".dwo");
+  return Sec.Name.endswith(".dwo");
 }
 
 static bool onlyKeepDWOPred(const Object &Obj, const SectionBase &Sec) {
@@ -407,49 +405,6 @@ static Error dumpSectionToFile(StringRef SecName, StringRef Filename,
                                  object_error::parse_failed);
 }
 
-static bool isCompressed(const SectionBase &Section) {
-  ArrayRef<uint8_t> GnuPrefix = {'Z', 'L', 'I', 'B'};
-  return StringRef(Section.Name).startswith(".zdebug") ||
-         (Section.OriginalData.size() > strlen("ZLIB") &&
-          std::equal(GnuPrefix.begin(), GnuPrefix.end(),
-                     Section.OriginalData.data())) ||
-         (Section.Flags & ELF::SHF_COMPRESSED);
-}
-
-static bool isCompressable(const SectionBase &Section) {
-  return !isCompressed(Section) && isDebugSection(Section) &&
-         Section.Name != ".gdb_index";
-}
-
-static void compressSections(const CopyConfig &Config, Object &Obj,
-                             SectionPred &RemovePred) {
-  SmallVector<SectionBase *, 13> ToCompress;
-  SmallVector<RelocationSection *, 13> RelocationSections;
-  for (auto &Sec : Obj.sections()) {
-    if (RelocationSection *R = dyn_cast<RelocationSection>(&Sec)) {
-      if (isCompressable(*R->getSection()))
-        RelocationSections.push_back(R);
-      continue;
-    }
-
-    if (isCompressable(Sec))
-      ToCompress.push_back(&Sec);
-  }
-
-  for (SectionBase *S : ToCompress) {
-    CompressedSection &CS =
-        Obj.addSection<CompressedSection>(*S, Config.CompressionType);
-
-    for (RelocationSection *RS : RelocationSections) {
-      if (RS->getSection() == S)
-        RS->setSection(&CS);
-    }
-  }
-
-  RemovePred = [RemovePred](const SectionBase &Sec) {
-    return isCompressable(Sec) || RemovePred(Sec);
-  };
-}
 // This function handles the high level operations of GNU objcopy including
 // handling command line options. It's important to outline certain properties
 // we expect to hold of the command line operations. Any operation that "keeps"
@@ -609,7 +564,7 @@ static void handleArgs(const CopyConfig &Config, Object &Obj,
         return true;
       if (&Sec == Obj.SectionNames)
         return false;
-      if (StringRef(Sec.Name).startswith(".gnu.warning"))
+      if (Sec.Name.startswith(".gnu.warning"))
         return false;
       return (Sec.Flags & SHF_ALLOC) == 0;
     };
@@ -661,9 +616,6 @@ static void handleArgs(const CopyConfig &Config, Object &Obj,
     };
   }
 
-  if (Config.CompressionType != DebugCompressionType::None)
-    compressSections(Config, Obj, RemovePred);
-
   Obj.removeSections(RemovePred);
 
   if (!Config.SectionsToRename.empty()) {
@@ -908,23 +860,6 @@ static CopyConfig parseObjcopyOptions(ArrayRef<const char *> ArgsArr) {
     Config.BinaryArch = getMachineInfo(BinaryArch);
   }
 
-  if (auto Arg = InputArgs.getLastArg(OBJCOPY_compress_debug_sections,
-                                      OBJCOPY_compress_debug_sections_eq)) {
-    Config.CompressionType = DebugCompressionType::Z;
-
-    if (Arg->getOption().getID() == OBJCOPY_compress_debug_sections_eq) {
-      Config.CompressionType =
-          StringSwitch<DebugCompressionType>(
-              InputArgs.getLastArgValue(OBJCOPY_compress_debug_sections_eq))
-              .Case("zlib-gnu", DebugCompressionType::GNU)
-              .Case("zlib", DebugCompressionType::Z)
-              .Default(DebugCompressionType::None);
-      if (Config.CompressionType == DebugCompressionType::None)
-        error("Invalid or unsupported --compress-debug-sections format: " +
-              InputArgs.getLastArgValue(OBJCOPY_compress_debug_sections_eq));
-    }
-  }
-
   Config.SplitDWO = InputArgs.getLastArgValue(OBJCOPY_split_dwo);
   Config.AddGnuDebugLink = InputArgs.getLastArgValue(OBJCOPY_add_gnu_debuglink);
   Config.SymbolsPrefix = InputArgs.getLastArgValue(OBJCOPY_prefix_symbols);