[lld] r328686 - Initialize OffsetMap in a known location.

[Rafael Espindola via llvm-commits]

Author: rafael
Date: Tue Mar 27 20:20:18 2018
New Revision: 328686

URL: http://llvm.org/viewvc/llvm-project?rev=328686&view=rev
Log:
Initialize OffsetMap in a known location.

This is a small optimization and avoids the need to use call_once.

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

Modified: lld/trunk/ELF/InputSection.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.cpp?rev=328686&r1=328685&r2=328686&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.cpp (original)
+++ lld/trunk/ELF/InputSection.cpp Tue Mar 27 20:20:18 2018
@@ -958,13 +958,6 @@ uint64_t MergeInputSection::getOffset(ui
   if (!Live)
     return 0;
 
-  // Initialize OffsetMap lazily.
-  llvm::call_once(InitOffsetMap, [&] {
-    OffsetMap.reserve(Pieces.size());
-    for (size_t I = 0; I < Pieces.size(); ++I)
-      OffsetMap[Pieces[I].InputOff] = I;
-  });
-
   // Find a string starting at a given offset.
   auto It = OffsetMap.find(Offset);
   if (It != OffsetMap.end())
@@ -980,6 +973,12 @@ uint64_t MergeInputSection::getOffset(ui
   return Piece.OutputOff + Addend;
 }
 
+void MergeInputSection::initOffsetMap() {
+  OffsetMap.reserve(Pieces.size());
+  for (size_t I = 0; I < Pieces.size(); ++I)
+    OffsetMap[Pieces[I].InputOff] = I;
+}
+
 template InputSection::InputSection(ObjFile<ELF32LE> &, const ELF32LE::Shdr &,
                                     StringRef);
 template InputSection::InputSection(ObjFile<ELF32BE> &, const ELF32BE::Shdr &,

Modified: lld/trunk/ELF/InputSection.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.h?rev=328686&r1=328685&r2=328686&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.h (original)
+++ lld/trunk/ELF/InputSection.h Tue Mar 27 20:20:18 2018
@@ -18,8 +18,6 @@
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/TinyPtrVector.h"
 #include "llvm/Object/ELF.h"
-#include "llvm/Support/Threading.h"
-#include <mutex>
 
 namespace lld {
 namespace elf {
@@ -256,13 +254,13 @@ public:
   }
 
   SyntheticSection *getParent() const;
+  void initOffsetMap();
 
 private:
   void splitStrings(ArrayRef<uint8_t> A, size_t Size);
   void splitNonStrings(ArrayRef<uint8_t> A, size_t Size);
 
-  mutable llvm::DenseMap<uint32_t, uint32_t> OffsetMap;
-  mutable llvm::once_flag InitOffsetMap;
+  llvm::DenseMap<uint32_t, uint32_t> OffsetMap;
 
   llvm::DenseSet<uint32_t> LiveOffsets;
 };

Modified: lld/trunk/ELF/SyntheticSections.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SyntheticSections.cpp?rev=328686&r1=328685&r2=328686&view=diff
==============================================================================
--- lld/trunk/ELF/SyntheticSections.cpp (original)
+++ lld/trunk/ELF/SyntheticSections.cpp Tue Mar 27 20:20:18 2018
@@ -2573,8 +2573,11 @@ void elf::mergeSections() {
     }
     (*I)->addSection(MS);
   }
-  for (auto *MS : MergeSections)
+  for (auto *MS : MergeSections) {
     MS->finalizeContents();
+    parallelForEach(MS->Sections,
+                    [](MergeInputSection *Sec) { Sec->initOffsetMap(); });
+  }
 
   std::vector<InputSectionBase *> &V = InputSections;
   V.erase(std::remove(V.begin(), V.end(), nullptr), V.end());

Modified: lld/trunk/ELF/SyntheticSections.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SyntheticSections.h?rev=328686&r1=328685&r2=328686&view=diff
==============================================================================
--- lld/trunk/ELF/SyntheticSections.h (original)
+++ lld/trunk/ELF/SyntheticSections.h Tue Mar 27 20:20:18 2018
@@ -684,13 +684,12 @@ public:
 class MergeSyntheticSection : public SyntheticSection {
 public:
   void addSection(MergeInputSection *MS);
+  std::vector<MergeInputSection *> Sections;
 
 protected:
   MergeSyntheticSection(StringRef Name, uint32_t Type, uint64_t Flags,
                         uint32_t Alignment)
       : SyntheticSection(Flags, Type, Alignment, Name) {}
-
-  std::vector<MergeInputSection *> Sections;
 };
 
 class MergeTailSection final : public MergeSyntheticSection {