[PATCH] D59019: [llvm-objcopy] - Remove an excessive zlib::isAvailable() check and dead code.

[George Rimar via Phabricator via llvm-commits]

grimar created this revision.
grimar added a reviewer: jhenderson.
Herald added subscribers: jdoerfert, MaskRay, jakehehrlich, arichardson, emaste.
Herald added a reviewer: espindola.
Herald added a reviewer: alexshap.
Herald added a reviewer: rupprecht.

There are 2 places where llvm-objcopy creates `CompressedSection`:

1. For `--compress-debug-sections`. It might create the compressed section from

regular here:
https://github.com/llvm-mirror/llvm/blob/master/tools/llvm-objcopy/ELF/ELFObjcopy.cpp#L486

2. All initially compressed sections are created as `CompressedSection` during reading the sections

from an object:
https://github.com/llvm-mirror/llvm/blob/master/tools/llvm-objcopy/ELF/Object.cpp#L1118
Those have `DebugCompressionType::None` type and a different constructor.

Case 1 has the following code in its constructor:

  if (!zlib::isAvailable()) {
    CompressionType = DebugCompressionType::None;
    return;
  }

(https://github.com/llvm-mirror/llvm/blob/master/tools/llvm-objcopy/ELF/Object.cpp#L267)

We can never reach that code with because would report an error much earlier:
https://github.com/llvm-mirror/llvm/blob/master/tools/llvm-objcopy/CopyConfig.cpp#L480

So the code I am removing is dead. Landing this will address the issue mentioned in https://bugs.llvm.org/show_bug.cgi?id=40886.


https://reviews.llvm.org/D59019

Files:
  tools/llvm-objcopy/ELF/Object.cpp


Index: tools/llvm-objcopy/ELF/Object.cpp
===================================================================
--- tools/llvm-objcopy/ELF/Object.cpp
+++ tools/llvm-objcopy/ELF/Object.cpp
@@ -263,12 +263,6 @@
                                      DebugCompressionType CompressionType)
     : SectionBase(Sec), CompressionType(CompressionType),
       DecompressedSize(Sec.OriginalData.size()), DecompressedAlign(Sec.Align) {
-
-  if (!zlib::isAvailable()) {
-    CompressionType = DebugCompressionType::None;
-    return;
-  }
-
   if (Error E = zlib::compress(
           StringRef(reinterpret_cast<const char *>(OriginalData.data()),
                     OriginalData.size()),


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