[lld] r311056 - Remove a lock and use a std::unique_ptr instead.

[Rui Ueyama via llvm-commits]

Author: ruiu
Date: Wed Aug 16 17:27:55 2017
New Revision: 311056

URL: http://llvm.org/viewvc/llvm-project?rev=311056&view=rev
Log:
Remove a lock and use a std::unique_ptr instead.

We had a lock to guard BAlloc from being used concurrently, but that
is not very easy to understand. This patch replaces it with a
std::unique_ptr.

Modified:
    lld/trunk/ELF/InputSection.cpp
    lld/trunk/ELF/InputSection.h

Modified: lld/trunk/ELF/InputSection.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.cpp?rev=311056&r1=311055&r2=311056&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.cpp (original)
+++ lld/trunk/ELF/InputSection.cpp Wed Aug 16 17:27:55 2017
@@ -200,17 +200,12 @@ void InputSectionBase::uncompress() {
                                                 Config->IsLE, Config->Is64));
 
   size_t Size = Dec.getDecompressedSize();
-  char *OutputBuf;
-  {
-    static std::mutex Mu;
-    std::lock_guard<std::mutex> Lock(Mu);
-    OutputBuf = BAlloc.Allocate<char>(Size);
-  }
-
-  if (Error E = Dec.decompress({OutputBuf, Size}))
+  UncompressBuf.reset(new std::vector<uint8_t>(Size));
+  if (Error E = Dec.decompress({(char *)UncompressBuf->data(), Size}))
     fatal(toString(this) +
           ": decompress failed: " + llvm::toString(std::move(E)));
-  this->Data = ArrayRef<uint8_t>((uint8_t *)OutputBuf, Size);
+
+  this->Data = *UncompressBuf;
   this->Flags &= ~(uint64_t)SHF_COMPRESSED;
 }
 

Modified: lld/trunk/ELF/InputSection.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.h?rev=311056&r1=311055&r2=311056&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.h (original)
+++ lld/trunk/ELF/InputSection.h Wed Aug 16 17:27:55 2017
@@ -183,6 +183,11 @@ public:
     assert(S % sizeof(T) == 0);
     return llvm::makeArrayRef<T>((const T *)Data.data(), S / sizeof(T));
   }
+
+private:
+  // A pointer that owns uncompressed data if a section is compressed by zlib.
+  // Since the feature is not used often, this is usually a nullptr.
+  std::unique_ptr<std::vector<uint8_t>> UncompressBuf;
 };
 
 // SectionPiece represents a piece of splittable section contents.