Revert "[llvm-objcopy] Add --compress-sections"

This reverts commit 9e3b64b.

Reason: Broke the UBSan buildbot. See the comments in the pull request
(#85036) for more information.

llvm/docs/CommandGuide/llvm-objcopy.rst

@@ -309,14 +309,6 @@ them.
  Compress DWARF debug sections in the output, using the specified format.
  Supported formats are ``zlib`` and ``zstd``. Use ``zlib`` if ``<format>`` is omitted.
 
-.. option:: --compress-sections <section>=<format>
-
- Compress or decompress sections matched by ``<section>`` using the specified
- format. Supported formats are ``zlib`` and ``zstd``. Specify ``none`` for
- decompression. When a section is matched by multiple options, the last one
- wins. A wildcard ``<section>`` starting with '!' is disallowed.
- Sections within a segment cannot be (de)compressed.
-
 .. option:: --decompress-debug-sections
 
  Decompress any compressed DWARF debug sections in the output.

llvm/docs/ReleaseNotes.rst

@@ -182,10 +182,6 @@ Changes to the LLVM tools
   for ELF input to skip the specified symbols when executing other options
   that can change a symbol's name, binding or visibility.
 
-* llvm-objcopy now supports ``--compress-sections`` to compress or decompress
-  arbitrary sections not within a segment.
-  (`#85036 <https://github.com/llvm/llvm-project/pull/85036>`_.)
-
 * llvm-profgen now supports COFF+DWARF binaries. This enables Sample-based PGO
   on Windows using Intel VTune's SEP. For details on usage, see the `end-user
   documentation for SPGO

llvm/include/llvm/ObjCopy/CommonConfig.h

@@ -262,9 +262,6 @@ struct CommonConfig {
   bool DecompressDebugSections = false;
 
   DebugCompressionType CompressionType = DebugCompressionType::None;
-
-  SmallVector<std::pair<NameMatcher, llvm::DebugCompressionType>, 0>
-      compressSections;
 };
 
 } // namespace objcopy

llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp

@@ -215,41 +215,23 @@ static Error dumpSectionToFile(StringRef SecName, StringRef Filename,
 }
 
 Error Object::compressOrDecompressSections(const CommonConfig &Config) {
-  // Build a list of sections we are going to replace.
-  // We can't call `addSection` while iterating over sections,
+  // Build a list of the debug sections we are going to replace.
+  // We can't call `AddSection` while iterating over sections,
   // because it would mutate the sections array.
   SmallVector<std::pair<SectionBase *, std::function<SectionBase *()>>, 0>
       ToReplace;
   for (SectionBase &Sec : sections()) {
-    std::optional<DebugCompressionType> CType;
-    for (auto &[Matcher, T] : Config.compressSections)
-      if (Matcher.matches(Sec.Name))
-        CType = T;
-    // Handle --compress-debug-sections and --decompress-debug-sections, which
-    // apply to non-ALLOC debug sections.
-    if (!(Sec.Flags & SHF_ALLOC) && StringRef(Sec.Name).starts_with(".debug")) {
-      if (Config.CompressionType != DebugCompressionType::None)
-        CType = Config.CompressionType;
-      else if (Config.DecompressDebugSections)
-        CType = DebugCompressionType::None;
-    }
-    if (!CType)
+    if ((Sec.Flags & SHF_ALLOC) || !StringRef(Sec.Name).starts_with(".debug"))
       continue;
-
-    if (Sec.ParentSegment)
-      return createStringError(
-          errc::invalid_argument,
-          "section '" + Sec.Name +
-              "' within a segment cannot be (de)compressed");
-
     if (auto *CS = dyn_cast<CompressedSection>(&Sec)) {
-      if (*CType == DebugCompressionType::None)
+      if (Config.DecompressDebugSections) {
         ToReplace.emplace_back(
             &Sec, [=] { return &addSection<DecompressedSection>(*CS); });
-    } else if (*CType != DebugCompressionType::None) {
-      ToReplace.emplace_back(&Sec, [=, S = &Sec] {
+      }
+    } else if (Config.CompressionType != DebugCompressionType::None) {
+      ToReplace.emplace_back(&Sec, [&, S = &Sec] {
         return &addSection<CompressedSection>(
-            CompressedSection(*S, *CType, Is64Bits));
+            CompressedSection(*S, Config.CompressionType, Is64Bits));
       });
     }
   }

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

@@ -4,42 +4,13 @@
 # RUN: yaml2obj %s -o %t
 # RUN: llvm-objcopy --decompress-debug-sections %t %t.de
 # RUN: llvm-readelf -S %t.de | FileCheck %s
-# RUN: llvm-objcopy --compress-sections '*nonalloc=none' --compress-sections .debugx=none %t %t.1.de
-# RUN: cmp %t.de %t.1.de
 
 # CHECK:        Name              Type            Address          Off      Size     ES Flg Lk Inf Al
 # CHECK:        .debug_alloc      PROGBITS        0000000000000000 [[#%x,]] [[#%x,]] 00  AC  0   0  0
 # CHECK-NEXT:   .debug_nonalloc   PROGBITS        0000000000000000 [[#%x,]] [[#%x,]] 00      0   0  1
 # CHECK-NEXT:   .debugx           PROGBITS        0000000000000000 [[#%x,]] [[#%x,]] 00      0   0  1
 # CHECK-NEXT:   nodebug           PROGBITS        0000000000000000 [[#%x,]] [[#%x,]] 00   C  0   0  0
 
-# RUN: llvm-objcopy --compress-sections '.debug*=none' %t %t2.de
-# RUN: llvm-readelf -S -x .debug_alloc -x .debug_nonalloc -x .debugx %t2.de | FileCheck %s --check-prefix=CHECK2
-
-# CHECK2:        Name              Type            Address          Off      Size     ES Flg Lk Inf Al
-# CHECK2:        .debug_alloc      PROGBITS        0000000000000000 [[#%x,]] [[#%x,]] 00  A   0   0  1
-# CHECK2-NEXT:   .debug_nonalloc   PROGBITS        0000000000000000 [[#%x,]] [[#%x,]] 00      0   0  1
-# CHECK2-NEXT:   .debugx           PROGBITS        0000000000000000 [[#%x,]] [[#%x,]] 00      0   0  1
-# CHECK2-NEXT:   nodebug           PROGBITS        0000000000000000 [[#%x,]] [[#%x,]] 00   C  0   0  0
-
-# CHECK2:       Hex dump of section '.debug_alloc':
-# CHECK2-NEXT:  0x00000000 2a000000 00000000 2a000000 00000000 *.......*.......
-# CHECK2-NEXT:  0x00000010 2a000000 00000000 2a000000 00000000 *.......*.......
-# CHECK2-NEXT:  0x00000020 2a000000 00000000 2a000000 00000000 *.......*.......
-# CHECK2-NEXT:  0x00000030 2a000000 00000000 2a000000 00000000 *.......*.......
-# CHECK2-EMPTY:
-# CHECK2:       Hex dump of section '.debug_nonalloc':
-# CHECK2-NEXT:  0x00000000 2a000000 00000000 2a000000 00000000 *.......*.......
-# CHECK2-NEXT:  0x00000010 2a000000 00000000 2a000000 00000000 *.......*.......
-# CHECK2-NEXT:  0x00000020 2a000000 00000000 2a000000 00000000 *.......*.......
-# CHECK2-NEXT:  0x00000030 2a000000 00000000 2a000000 00000000 *.......*.......
-# CHECK2-EMPTY:
-# CHECK2-NEXT:  Hex dump of section '.debugx':
-# CHECK2-NEXT:  0x00000000 2a000000 00000000 2a000000 00000000 *.......*.......
-# CHECK2-NEXT:  0x00000010 2a000000 00000000 2a000000 00000000 *.......*.......
-# CHECK2-NEXT:  0x00000020 2a000000 00000000 2a000000 00000000 *.......*.......
-# CHECK2-NEXT:  0x00000030 2a000000 00000000 2a000000 00000000 *.......*.......
-
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64

llvm/tools/llvm-objcopy/ObjcopyOptions.cpp

@@ -736,42 +736,6 @@ objcopy::parseObjcopyOptions(ArrayRef<const char *> RawArgsArr,
       return createStringError(errc::invalid_argument, Reason);
   }
 
-  for (const auto *A : InputArgs.filtered(OBJCOPY_compress_sections)) {
-    SmallVector<StringRef, 0> Fields;
-    StringRef(A->getValue()).split(Fields, '=');
-    if (Fields.size() != 2 || Fields[1].empty()) {
-      return createStringError(
-          errc::invalid_argument,
-          A->getSpelling() +
-              ": parse error, not 'section-glob=[none|zlib|zstd]'");
-    }
-
-    auto Type = StringSwitch<DebugCompressionType>(Fields[1])
-                    .Case("zlib", DebugCompressionType::Zlib)
-                    .Case("zstd", DebugCompressionType::Zstd)
-                    .Default(DebugCompressionType::None);
-    if (Type == DebugCompressionType::None && Fields[1] != "none") {
-      return createStringError(
-          errc::invalid_argument,
-          "invalid or unsupported --compress-sections format: %s",
-          A->getValue());
-    }
-
-    auto &P = Config.compressSections.emplace_back();
-    P.second = Type;
-    auto Matcher =
-        NameOrPattern::create(Fields[0], SectionMatchStyle, ErrorCallback);
-    // =none allows overriding a previous =zlib or =zstd. Reject negative
-    // patterns, which would be confusing.
-    if (Matcher && !Matcher->isPositiveMatch()) {
-      return createStringError(
-          errc::invalid_argument,
-          "--compress-sections: negative pattern is unsupported");
-    }
-    if (Error E = P.first.addMatcher(std::move(Matcher)))
-      return std::move(E);
-  }
-
   Config.AddGnuDebugLink = InputArgs.getLastArgValue(OBJCOPY_add_gnu_debuglink);
   // The gnu_debuglink's target is expected to not change or else its CRC would
   // become invalidated and get rejected. We can avoid recalculating the

llvm/tools/llvm-objcopy/ObjcopyOpts.td

@@ -35,12 +35,6 @@ def : Flag<["--"], "compress-debug-sections">, Alias<compress_debug_sections>,
       AliasArgs<["zlib"]>;
 def decompress_debug_sections : Flag<["--"], "decompress-debug-sections">,
                                 HelpText<"Decompress DWARF debug sections">;
-defm compress_sections
-    : Eq<"compress-sections",
-         "Compress or decompress sections using specified format. Supported "
-         "formats: zlib, zstd. Specify 'none' for decompression">,
-      MetaVarName<"<section-glob>=<format>">;
-
 defm split_dwo
     : Eq<"split-dwo", "Equivalent to --extract-dwo and <dwo-file> as the output file and no other options, "
                       "and then --strip-dwo on the input file">,