[lld] r249987 - ELF2: Use SmallPtrSet instead of unordered_set.

[Rui Ueyama via llvm-commits]

Author: ruiu
Date: Sun Oct 11 12:44:22 2015
New Revision: 249987

URL: http://llvm.org/viewvc/llvm-project?rev=249987&view=rev
Log:
ELF2: Use SmallPtrSet instead of unordered_set.

This patch addresses Rafael's review comments to r249955.

Modified:
    lld/trunk/ELF/Writer.cpp

Modified: lld/trunk/ELF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=249987&r1=249986&r2=249987&view=diff
==============================================================================
--- lld/trunk/ELF/Writer.cpp (original)
+++ lld/trunk/ELF/Writer.cpp Sun Oct 11 12:44:22 2015
@@ -13,8 +13,8 @@
 #include "SymbolTable.h"
 #include "Target.h"
 
+#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/Support/FileOutputBuffer.h"
-#include <unordered_set>
 
 using namespace llvm;
 using namespace llvm::ELF;
@@ -473,6 +473,9 @@ template <class ELFT> void Writer<ELFT>:
       ++NumPhdrs;
     }
   }
+
+  // Reserve space needed for the program header so that the array
+  // will never be resized.
   Phdrs.reserve(NumPhdrs);
 
   // The first Phdr entry is PT_PHDR which describes the program header itself.
@@ -494,7 +497,7 @@ template <class ELFT> void Writer<ELFT>:
   Elf_Phdr *FileHeader = &Phdrs.back();
   phdrSet(FileHeader, PT_LOAD, PF_R, 0, getVAStart(), Target->getPageSize());
 
-  std::unordered_set<Elf_Phdr *> Closed;
+  SmallPtrSet<Elf_Phdr *, 8> Closed;
   for (OutputSectionBase<ELFT::Is64Bits> *Sec : OutputSections) {
     if (Sec->getSize()) {
       uintX_t Flags = toPhdrFlags(Sec->getFlags());