[PATCH] D37774: Remove CopyRelSecOff from SharedSymbol

[Rafael Ávila de Espíndola via Phabricator via llvm-commits]

rafael created this revision.
Herald added a subscriber: emaste.

This reduces the size of SharedSymbol which in turn reduces the size of Symbol from 88 to 80 bytes.


https://reviews.llvm.org/D37774

Files:
  ELF/Relocations.cpp
  ELF/Symbols.cpp
  ELF/Symbols.h


Index: ELF/Symbols.h
===================================================================
--- ELF/Symbols.h
+++ ELF/Symbols.h
@@ -243,7 +243,6 @@
 
   // CopyRelSec and CopyRelSecOff are significant only when NeedsCopy is true.
   InputSection *CopyRelSec;
-  uint64_t CopyRelSecOff;
 
 private:
   template <class ELFT> const typename ELFT::Sym &getSym() const {
Index: ELF/Symbols.cpp
===================================================================
--- ELF/Symbols.cpp
+++ ELF/Symbols.cpp
@@ -108,8 +108,7 @@
   case SymbolBody::SharedKind: {
     auto &SS = cast<SharedSymbol>(Body);
     if (SS.CopyRelSec)
-      return SS.CopyRelSec->getParent()->Addr + SS.CopyRelSec->OutSecOff +
-             SS.CopyRelSecOff;
+      return SS.CopyRelSec->getParent()->Addr + SS.CopyRelSec->OutSecOff;
     if (SS.NeedsPltAddr)
       return Body.getPltVA();
     return 0;
Index: ELF/Relocations.cpp
===================================================================
--- ELF/Relocations.cpp
+++ ELF/Relocations.cpp
@@ -525,16 +525,21 @@
   // See if this symbol is in a read-only segment. If so, preserve the symbol's
   // memory protection by reserving space in the .bss.rel.ro section.
   bool IsReadOnly = isReadOnly<ELFT>(SS);
-  BssSection *Sec = IsReadOnly ? InX::BssRelRo : InX::Bss;
+  BssSection *Sec = make<BssSection>(IsReadOnly ? ".bss.rel.ro" : ".bss");
   uint64_t Off = Sec->reserveSpace(SymSize, SS->getAlignment<ELFT>());
+  if (IsReadOnly)
+    InX::BssRelRo->getParent()->addSection(Sec);
+  else
+    InX::Bss->getParent()->addSection(Sec);
+  assert(Off == 0);
+  (void)Off;
 
   // Look through the DSO's dynamic symbol table for aliases and create a
   // dynamic symbol for each one. This causes the copy relocation to correctly
   // interpose any aliases.
   for (SharedSymbol *Sym : getSymbolsAt<ELFT>(SS)) {
     Sym->CopyRelSec = Sec;
     Sym->IsPreemptible = false;
-    Sym->CopyRelSecOff = Off;
     Sym->symbol()->IsUsedInRegularObj = true;
   }
 


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