<div dir="ltr">Is it really worth/necessary to indirect this vector through a unique_ptr? Saves two words in the InputSection, I guess, in the common (not compressed) case? (could save the other word too, if you used a separate map to only store these things when needed)<br><br>But maybe this is the sweet spot of convenience and memory usage. Just curious/checking :)</div><br><div class="gmail_quote"><div dir="ltr">On Wed, Aug 16, 2017 at 5:28 PM Rui Ueyama via llvm-commits <<a href="mailto:llvm-commits@lists.llvm.org">llvm-commits@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: ruiu<br>
Date: Wed Aug 16 17:27:55 2017<br>
New Revision: 311056<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=311056&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project?rev=311056&view=rev</a><br>
Log:<br>
Remove a lock and use a std::unique_ptr instead.<br>
<br>
We had a lock to guard BAlloc from being used concurrently, but that<br>
is not very easy to understand. This patch replaces it with a<br>
std::unique_ptr.<br>
<br>
Modified:<br>
    lld/trunk/ELF/InputSection.cpp<br>
    lld/trunk/ELF/InputSection.h<br>
<br>
Modified: lld/trunk/ELF/InputSection.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.cpp?rev=311056&r1=311055&r2=311056&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.cpp?rev=311056&r1=311055&r2=311056&view=diff</a><br>
==============================================================================<br>
--- lld/trunk/ELF/InputSection.cpp (original)<br>
+++ lld/trunk/ELF/InputSection.cpp Wed Aug 16 17:27:55 2017<br>
@@ -200,17 +200,12 @@ void InputSectionBase::uncompress() {<br>
                                                 Config->IsLE, Config->Is64));<br>
<br>
   size_t Size = Dec.getDecompressedSize();<br>
-  char *OutputBuf;<br>
-  {<br>
-    static std::mutex Mu;<br>
-    std::lock_guard<std::mutex> Lock(Mu);<br>
-    OutputBuf = BAlloc.Allocate<char>(Size);<br>
-  }<br>
-<br>
-  if (Error E = Dec.decompress({OutputBuf, Size}))<br>
+  UncompressBuf.reset(new std::vector<uint8_t>(Size));<br>
+  if (Error E = Dec.decompress({(char *)UncompressBuf->data(), Size}))<br>
     fatal(toString(this) +<br>
           ": decompress failed: " + llvm::toString(std::move(E)));<br>
-  this->Data = ArrayRef<uint8_t>((uint8_t *)OutputBuf, Size);<br>
+<br>
+  this->Data = *UncompressBuf;<br>
   this->Flags &= ~(uint64_t)SHF_COMPRESSED;<br>
 }<br>
<br>
<br>
Modified: lld/trunk/ELF/InputSection.h<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.h?rev=311056&r1=311055&r2=311056&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.h?rev=311056&r1=311055&r2=311056&view=diff</a><br>
==============================================================================<br>
--- lld/trunk/ELF/InputSection.h (original)<br>
+++ lld/trunk/ELF/InputSection.h Wed Aug 16 17:27:55 2017<br>
@@ -183,6 +183,11 @@ public:<br>
     assert(S % sizeof(T) == 0);<br>
     return llvm::makeArrayRef<T>((const T *)Data.data(), S / sizeof(T));<br>
   }<br>
+<br>
+private:<br>
+  // A pointer that owns uncompressed data if a section is compressed by zlib.<br>
+  // Since the feature is not used often, this is usually a nullptr.<br>
+  std::unique_ptr<std::vector<uint8_t>> UncompressBuf;<br>
 };<br>
<br>
 // SectionPiece represents a piece of splittable section contents.<br>
<br>
<br>
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</blockquote></div>