Revert D130458 "[llvm-objcopy] Support --{,de}compress-debug-sections for zstd"

This reverts commit c26dc2904b.

The new Zstd dispatch has an ongoing design discussion related to https://reviews.llvm.org/D130516#3688123 .
Revert for now before it is resolved.

llvm/docs/CommandGuide/llvm-objcopy.rst

@@ -299,7 +299,7 @@ them.
 .. option:: --compress-debug-sections [<format>]
 
  Compress DWARF debug sections in the output, using the specified format.
- Supported formats are ``zlib`` and ``zstd``. Use ``zlib`` if ``<format>`` is omitted.
+ Supported formats are ``zlib``. Use ``zlib`` if ``<format>`` is omitted.
 
 .. option:: --decompress-debug-sections
 

llvm/include/llvm/BinaryFormat/ELF.h

@@ -1798,7 +1798,6 @@ struct Elf64_Nhdr {
 // Legal values for ch_type field of compressed section header.
 enum {
   ELFCOMPRESS_ZLIB = 1,            // ZLIB/DEFLATE algorithm.
-  ELFCOMPRESS_ZSTD = 2,            // Zstandard algorithm
   ELFCOMPRESS_LOOS = 0x60000000,   // Start of OS-specific.
   ELFCOMPRESS_HIOS = 0x6fffffff,   // End of OS-specific.
   ELFCOMPRESS_LOPROC = 0x70000000, // Start of processor-specific.

llvm/include/llvm/MC/MCTargetOptions.h

@@ -27,8 +27,7 @@ enum class ExceptionHandling {
 
 enum class DebugCompressionType {
   None, ///< No compression
-  Z,    ///< zlib
+  Z,    ///< zlib style complession
-  Zstd, ///< Zstandard
 };
 
 enum class EmitDwarfUnwindType {

llvm/lib/ObjCopy/ELF/ELFObject.cpp

@@ -438,32 +438,14 @@ template <class ELFT>
 Error ELFSectionWriter<ELFT>::visit(const DecompressedSection &Sec) {
   ArrayRef<uint8_t> Compressed =
       Sec.OriginalData.slice(sizeof(Elf_Chdr_Impl<ELFT>));
-  SmallVector<uint8_t, 128> Decompressed;
+  SmallVector<uint8_t, 128> DecompressedContent;
-  auto Report = [&](Error Err) {
+  if (Error Err = compression::zlib::uncompress(Compressed, DecompressedContent,
-    return createStringError(errc::invalid_argument,
-                             "failed to decompress section '" + Sec.Name +
-                                 "': " + toString(std::move(Err)));
-  };
-  switch (Sec.ChType) {
-  case ELFCOMPRESS_ZLIB:
-    if (Error E = compression::zlib::uncompress(Compressed, Decompressed,
                                                 static_cast<size_t>(Sec.Size)))
-      return Report(std::move(E));
-    break;
-  case ELFCOMPRESS_ZSTD:
-    if (Error E = compression::zstd::uncompress(Compressed, Decompressed,
-                                                static_cast<size_t>(Sec.Size)))
-      return Report(std::move(E));
-    break;
-  default:
     return createStringError(errc::invalid_argument,
-                             "--decompress-debug-sections: ch_type (" +
+                             "'" + Sec.Name + "': " + toString(std::move(Err)));
-                                 Twine(Sec.ChType) + ") of section '" +
-                                 Sec.Name + "' is unsupported");
-  }
 
   uint8_t *Buf = reinterpret_cast<uint8_t *>(Out.getBufferStart()) + Sec.Offset;
-  std::copy(Decompressed.begin(), Decompressed.end(), Buf);
+  std::copy(DecompressedContent.begin(), DecompressedContent.end(), Buf);
 
   return Error::success();
 }
@@ -516,9 +498,6 @@ Error ELFSectionWriter<ELFT>::visit(const CompressedSection &Sec) {
   case DebugCompressionType::Z:
     Chdr.ch_type = ELF::ELFCOMPRESS_ZLIB;
     break;
-  case DebugCompressionType::Zstd:
-    Chdr.ch_type = ELF::ELFCOMPRESS_ZSTD;
-    break;
   }
   Chdr.ch_size = Sec.DecompressedSize;
   Chdr.ch_addralign = Sec.DecompressedAlign;
@@ -533,17 +512,9 @@ CompressedSection::CompressedSection(const SectionBase &Sec,
                                      DebugCompressionType CompressionType)
     : SectionBase(Sec), CompressionType(CompressionType),
       DecompressedSize(Sec.OriginalData.size()), DecompressedAlign(Sec.Align) {
-  switch (CompressionType) {
+  compression::zlib::compress(OriginalData, CompressedData);
-  case DebugCompressionType::Z:
-    compression::zlib::compress(OriginalData, CompressedData);
-    break;
-  case DebugCompressionType::Zstd:
-    compression::zstd::compress(OriginalData, CompressedData);
-    break;
-  case DebugCompressionType::None:
-    llvm_unreachable("should not use CompressedSection");
-  }
 
+  assert(CompressionType != DebugCompressionType::None);
   Flags |= ELF::SHF_COMPRESSED;
   size_t ChdrSize =
       std::max(std::max(sizeof(object::Elf_Chdr_Impl<object::ELF64LE>),
@@ -555,9 +526,9 @@ CompressedSection::CompressedSection(const SectionBase &Sec,
 }
 
 CompressedSection::CompressedSection(ArrayRef<uint8_t> CompressedData,
-                                     uint32_t ChType, uint64_t DecompressedSize,
+                                     uint64_t DecompressedSize,
                                      uint64_t DecompressedAlign)
-    : ChType(ChType), CompressionType(DebugCompressionType::None),
+    : CompressionType(DebugCompressionType::None),
       DecompressedSize(DecompressedSize), DecompressedAlign(DecompressedAlign) {
   OriginalData = CompressedData;
 }
@@ -1735,8 +1706,8 @@ Expected<SectionBase &> ELFBuilder<ELFT>::makeSection(const Elf_Shdr &Shdr) {
     if (!(Shdr.sh_flags & ELF::SHF_COMPRESSED))
       return Obj.addSection<Section>(*Data);
     auto *Chdr = reinterpret_cast<const Elf_Chdr_Impl<ELFT> *>(Data->data());
-    return Obj.addSection<CompressedSection>(CompressedSection(
+    return Obj.addSection<CompressedSection>(
-        *Data, Chdr->ch_type, Chdr->ch_size, Chdr->ch_addralign));
+        CompressedSection(*Data, Chdr->ch_size, Chdr->ch_addralign));
   }
   }
 }

llvm/lib/ObjCopy/ELF/ELFObject.h

@@ -536,7 +536,6 @@ public:
 class CompressedSection : public SectionBase {
   MAKE_SEC_WRITER_FRIEND
 
-  uint32_t ChType = 0;
   DebugCompressionType CompressionType;
   uint64_t DecompressedSize;
   uint64_t DecompressedAlign;
@@ -545,12 +544,11 @@ class CompressedSection : public SectionBase {
 public:
   CompressedSection(const SectionBase &Sec,
                     DebugCompressionType CompressionType);
-  CompressedSection(ArrayRef<uint8_t> CompressedData, uint32_t ChType,
+  CompressedSection(ArrayRef<uint8_t> CompressedData, uint64_t DecompressedSize,
-                    uint64_t DecompressedSize, uint64_t DecompressedAlign);
+                    uint64_t DecompressedAlign);
 
   uint64_t getDecompressedSize() const { return DecompressedSize; }
   uint64_t getDecompressedAlign() const { return DecompressedAlign; }
-  uint64_t getChType() const { return ChType; }
 
   Error accept(SectionVisitor &Visitor) const override;
   Error accept(MutableSectionVisitor &Visitor) override;
@@ -564,9 +562,8 @@ class DecompressedSection : public SectionBase {
   MAKE_SEC_WRITER_FRIEND
 
 public:
-  uint32_t ChType;
   explicit DecompressedSection(const CompressedSection &Sec)
-      : SectionBase(Sec), ChType(Sec.getChType()) {
+      : SectionBase(Sec) {
     Size = Sec.getDecompressedSize();
     Align = Sec.getDecompressedAlign();
     Flags = OriginalFlags = (Flags & ~ELF::SHF_COMPRESSED);

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

@@ -2,15 +2,12 @@
 
 # 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 --sd %t-compressed.o | FileCheck %s
+# 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:      SectionData (
-## ch_type = ELFCOMPRESS_ZLIB (1)
-# CHECK-NEXT:   0000: 01000000 {{.*}}
 # CHECK-NOT: Name: .debug_foo
 

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

@@ -28,21 +28,3 @@
 ## --compress-debug-sections does not update a compressed section.
 # RUN: llvm-objcopy --compress-debug-sections=zlib %t-zlib.o %t-zlib-zlib.o
 # RUN: cmp %t-zlib.o %t-zlib-zlib.o
-
-# RUN: yaml2obj %s -o %t-corrupted
-# RUN: not llvm-objcopy --decompress-debug-sections %t-corrupted /dev/null 2>&1 | FileCheck %s -DFILE=%t-corrupted --check-prefix=ERR
-
-# ERR: error: '[[FILE]]': failed to decompress section '.debug_info': zlib error: Z_DATA_ERROR
-
---- !ELF
-FileHeader:
-  Class:   ELFCLASS64
-  Data:    ELFDATA2LSB
-  Type:    ET_REL
-  Machine: EM_X86_64
-Sections:
-  - Type:         SHT_PROGBITS
-    Name:         .debug_info
-    Flags:        [ SHF_COMPRESSED ]
-    AddressAlign: 8
-    Content:      "010000000000000004000000000000000100000000000000ffffffff"

llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-zstd-err.test

@@ -1,5 +0,0 @@
-# UNSUPPORTED: zstd
-# RUN: yaml2obj %p/Inputs/compress-debug-sections.yaml -o %t
-# RUN: not llvm-objcopy --compress-debug-sections=zstd %t /dev/null 2>&1 | FileCheck %s
-
-# CHECK: error: LLVM was not compiled with LLVM_ENABLE_ZSTD: cannot compress

llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-zstd.test

@@ -1,51 +0,0 @@
-# REQUIRES: zstd
-## Test --compress-debug-sections=zstd and decompression.
-
-# RUN: yaml2obj %p/Inputs/compress-debug-sections.yaml -o %t && llvm-objcopy %t
-# RUN: llvm-objcopy --compress-debug-sections=zstd %t %t-zstd
-# RUN: llvm-objcopy --decompress-debug-sections %t-zstd %t-de
-# RUN: cmp %t %t-de
-
-# RUN: llvm-readelf -S -r -x .debug_foo %t-zstd | FileCheck %s --check-prefixes=CHECK,COMPRESSED
-# RUN: llvm-readelf -S -r -x .debug_foo %t-de | FileCheck %s --check-prefixes=CHECK,DECOMPRESSED
-
-# CHECK:             Name              Type            Address          Off    Size   ES Flg Lk Inf Al
-# COMPRESSED:        .debug_foo        PROGBITS        0000000000000000 000040 {{.*}} 00   C  0   0  8
-# COMPRESSED-NEXT:   .notdebug_foo     PROGBITS        0000000000000000 {{.*}} 000008 00      0   0  0
-# DECOMPRESSED:      .debug_foo        PROGBITS        0000000000000000 000040 000008 00      0   0  0
-# DECOMPRESSED-NEXT: .notdebug_foo     PROGBITS        0000000000000000 {{.*}} 000008 00      0   0  0
-
-## Relocations do not change.
-# CHECK:             Relocation section '.rela.debug_foo' at offset {{.*}} contains 2 entries:
-# CHECK-NEXT:            Offset
-# CHECK-NEXT:        0000000000000001  000000010000000a R_X86_64_32            0000000000000000 .debug_foo + 0
-# CHECK-NEXT:        0000000000000002  000000020000000a R_X86_64_32            0000000000000000 .notdebug_foo + 0
-
-# COMPRESSED:        Hex dump of section '.debug_foo':
-## ch_type == ELFCOMPRESS_ZSTD (2)
-# COMPRESSED-NEXT:   0x00000000 02000000 00000000 08000000 00000000
-# COMPRESSED-NEXT:   0x00000010 00000000 00000000 {{.*}}
-
-## --compress-debug-sections does not update a compressed section. Its compression
-## type does not change.
-# RUN: llvm-objcopy --compress-debug-sections=zstd %t-zstd %t-zstd-zstd
-# RUN: cmp %t-zstd %t-zstd-zstd
-# RUN: %if zlib %{ llvm-objcopy --compress-debug-sections=zlib %t-zstd %t-zstd-zlib && cmp %t-zstd %t-zstd-zlib %}
-
-# RUN: yaml2obj %s -o %t-corrupted
-# RUN: not llvm-objcopy --decompress-debug-sections %t-corrupted /dev/null 2>&1 | FileCheck %s -DFILE=%t-corrupted --check-prefix=ERR
-
-# ERR: error: '[[FILE]]': failed to decompress section '.debug_info': Src size is incorrect
-
---- !ELF
-FileHeader:
-  Class:   ELFCLASS64
-  Data:    ELFDATA2LSB
-  Type:    ET_REL
-  Machine: EM_X86_64
-Sections:
-  - Type:         SHT_PROGBITS
-    Name:         .debug_info
-    Flags:        [ SHF_COMPRESSED ]
-    AddressAlign: 8
-    Content:      "020000000000000004000000000000000100000000000000ffffffff"

llvm/test/tools/llvm-objcopy/ELF/decompress-debug-sections-err.test

@@ -1,24 +0,0 @@
-# REQUIRES: zlib
-# RUN: yaml2obj %s -o %t
-# RUN: not llvm-objcopy --decompress-debug-sections %t /dev/null 2>&1 | FileCheck %s -DFILE=%t
-
-# CHECK:       error: '[[FILE]]': --decompress-debug-sections: ch_type (3) of section '.debug_info' is unsupported
-# CHECK-EMPTY:
-
---- !ELF
-FileHeader:
-  Class:   ELFCLASS64
-  Data:    ELFDATA2LSB
-  Type:    ET_REL
-  Machine: EM_X86_64
-Sections:
-  - Name:         .debug_info
-    Type:         SHT_PROGBITS
-    Flags:        [ SHF_COMPRESSED ]
-    Content:      030000000000000004000000000000000000000000000000789c6360
-    AddressAlign: 8
-  - Name:         .debug_str
-    Type:         SHT_PROGBITS
-    Flags:        [ SHF_COMPRESSED ]
-    Content:      030000000000000004000000000000000000000000000000789c6360
-    AddressAlign: 8

llvm/tools/llvm-objcopy/ObjcopyOptions.cpp

@@ -722,27 +722,16 @@ objcopy::parseObjcopyOptions(ArrayRef<const char *> RawArgsArr,
   if (const auto *A = InputArgs.getLastArg(OBJCOPY_compress_debug_sections)) {
     Config.CompressionType = StringSwitch<DebugCompressionType>(A->getValue())
                                  .Case("zlib", DebugCompressionType::Z)
-                                 .Case("zstd", DebugCompressionType::Zstd)
                                  .Default(DebugCompressionType::None);
-    switch (Config.CompressionType) {
+    if (Config.CompressionType == DebugCompressionType::None)
-    case DebugCompressionType::None:
       return createStringError(
           errc::invalid_argument,
           "invalid or unsupported --compress-debug-sections format: %s",
           A->getValue());
-    case DebugCompressionType::Z:
+    if (!compression::zlib::isAvailable())
-      if (!compression::zlib::isAvailable())
+      return createStringError(
-        return createStringError(
+          errc::invalid_argument,
-            errc::invalid_argument,
+          "LLVM was not compiled with LLVM_ENABLE_ZLIB: can not compress");
-            "LLVM was not compiled with LLVM_ENABLE_ZLIB: cannot compress");
-      break;
-    case DebugCompressionType::Zstd:
-      if (!compression::zstd::isAvailable())
-        return createStringError(
-            errc::invalid_argument,
-            "LLVM was not compiled with LLVM_ENABLE_ZSTD: cannot compress");
-      break;
-    }
   }
 
   Config.AddGnuDebugLink = InputArgs.getLastArgValue(OBJCOPY_add_gnu_debuglink);

llvm/tools/llvm-objcopy/ObjcopyOpts.td

@@ -33,7 +33,7 @@ def compress_debug_sections
     : Joined<["--"], "compress-debug-sections=">,
       MetaVarName<"format">,
       HelpText<"Compress DWARF debug sections using specified format. Supported "
-               "formats: zlib, zstd. Select zlib if <format> is omitted">;
+               "formats: zlib">;
 def : Flag<["--"], "compress-debug-sections">, Alias<compress_debug_sections>,
       AliasArgs<["zlib"]>;
 def decompress_debug_sections : Flag<["--"], "decompress-debug-sections">,

llvm/utils/lit/lit/llvm/config.py

@@ -108,9 +108,6 @@ class LLVMConfig(object):
         have_zlib = getattr(config, 'have_zlib', None)
         if have_zlib:
             features.add('zlib')
-        have_zstd = getattr(config, 'have_zstd', None)
-        if have_zstd:
-            features.add('zstd')
 
         # Check if we should run long running tests.
         long_tests = lit_config.params.get('run_long_tests', None)