From 2812aa82d0cd9d626e4da81b5cf90dd3068aa3cc Mon Sep 17 00:00:00 2001
From: "Michael J. Spencer" <bigcheesegs@gmail.com>
Date: Wed, 23 Sep 2015 16:57:31 +0000
Subject: [PATCH] [elf2] Pass BSSSec to the relocation handling code
 differently. Don't store it in the symbol.

llvm-svn: 248393
---
 lld/ELF/InputSection.cpp   | 15 ++++++++++-----
 lld/ELF/InputSection.h     |  5 +++--
 lld/ELF/OutputSections.cpp |  2 +-
 lld/ELF/OutputSections.h   |  2 ++
 lld/ELF/Symbols.h          |  2 --
 lld/ELF/Writer.cpp         |  6 +++++-
 6 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
index dbdaa1d425ae..e8fa4a68356d 100644
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -29,7 +29,8 @@ template <bool isRela>
 void InputSection<ELFT>::relocate(
     uint8_t *Buf, iterator_range<const Elf_Rel_Impl<ELFT, isRela> *> Rels,
     const ObjectFile<ELFT> &File, uintX_t BaseAddr,
-    const PltSection<ELFT> &PltSec, const GotSection<ELFT> &GotSec) {
+    const OutputSection<ELFT> &BssSec, const PltSection<ELFT> &PltSec,
+    const GotSection<ELFT> &GotSec) {
   typedef Elf_Rel_Impl<ELFT, isRela> RelType;
   bool IsMips64EL = File.getObj()->isMips64EL();
   for (const RelType &RI : Rels) {
@@ -58,7 +59,7 @@ void InputSection<ELFT>::relocate(
         break;
       case SymbolBody::DefinedCommonKind: {
         auto *DC = cast<DefinedCommon<ELFT>>(Body);
-        SymVA = DC->OutputSec->getVA() + DC->OffsetInBSS;
+        SymVA = BssSec.getVA() + DC->OffsetInBSS;
         break;
       }
       case SymbolBody::SharedKind:
@@ -87,7 +88,9 @@ void InputSection<ELFT>::relocate(
 }
 
 template <class ELFT>
-void InputSection<ELFT>::writeTo(uint8_t *Buf, const PltSection<ELFT> &PltSec,
+void InputSection<ELFT>::writeTo(uint8_t *Buf,
+                                 const OutputSection<ELFT> &BssSec,
+                                 const PltSection<ELFT> &PltSec,
                                  const GotSection<ELFT> &GotSec) {
   if (Header->sh_type == SHT_NOBITS)
     return;
@@ -102,9 +105,11 @@ void InputSection<ELFT>::writeTo(uint8_t *Buf, const PltSection<ELFT> &PltSec,
   // Iterate over all relocation sections that apply to this section.
   for (const Elf_Shdr *RelSec : RelocSections) {
     if (RelSec->sh_type == SHT_RELA)
-      relocate(Base, EObj->relas(RelSec), *File, BaseAddr, PltSec, GotSec);
+      relocate(Base, EObj->relas(RelSec), *File, BaseAddr, BssSec, PltSec,
+               GotSec);
     else
-      relocate(Base, EObj->rels(RelSec), *File, BaseAddr, PltSec, GotSec);
+      relocate(Base, EObj->rels(RelSec), *File, BaseAddr, BssSec, PltSec,
+               GotSec);
   }
 }
 
diff --git a/lld/ELF/InputSection.h b/lld/ELF/InputSection.h
index b8a7b7531a7f..f0de99ec0848 100644
--- a/lld/ELF/InputSection.h
+++ b/lld/ELF/InputSection.h
@@ -37,8 +37,8 @@ public:
 
   // Write this section to a mmap'ed file, assuming Buf is pointing to
   // beginning of the output section.
-  void writeTo(uint8_t *Buf, const PltSection<ELFT> &PltSec,
-               const GotSection<ELFT> &GotSec);
+  void writeTo(uint8_t *Buf, const OutputSection<ELFT> &BssSec,
+               const PltSection<ELFT> &PltSec, const GotSection<ELFT> &GotSec);
 
   StringRef getSectionName() const;
   const Elf_Shdr *getSectionHdr() const { return Header; }
@@ -65,6 +65,7 @@ private:
                 llvm::iterator_range<
                     const llvm::object::Elf_Rel_Impl<ELFT, isRela> *> Rels,
                 const ObjectFile<ELFT> &File, uintX_t BaseAddr,
+                const OutputSection<ELFT> &BssSec,
                 const PltSection<ELFT> &PltSec, const GotSection<ELFT> &GotSec);
 
   // The offset from beginning of the output sections this section was assigned
diff --git a/lld/ELF/OutputSections.cpp b/lld/ELF/OutputSections.cpp
index 7b2533846e2e..c152fe3d9858 100644
--- a/lld/ELF/OutputSections.cpp
+++ b/lld/ELF/OutputSections.cpp
@@ -252,7 +252,7 @@ lld::elf2::getLocalSymVA(const typename ELFFile<ELFT>::Elf_Sym *Sym,
 
 template <class ELFT> void OutputSection<ELFT>::writeTo(uint8_t *Buf) {
   for (InputSection<ELFT> *C : Sections)
-    C->writeTo(Buf, PltSec, GotSec);
+    C->writeTo(Buf, *BssSec, PltSec, GotSec);
 }
 
 template <bool Is64Bits>
diff --git a/lld/ELF/OutputSections.h b/lld/ELF/OutputSections.h
index 38706b9361f5..6ece9adf4d2e 100644
--- a/lld/ELF/OutputSections.h
+++ b/lld/ELF/OutputSections.h
@@ -242,11 +242,13 @@ public:
 
   void addSection(InputSection<ELFT> *C);
   void writeTo(uint8_t *Buf) override;
+  void setBssSec(const OutputSection<ELFT> *BS) { BssSec = BS; }
 
 private:
   std::vector<InputSection<ELFT> *> Sections;
   const PltSection<ELFT> &PltSec;
   const GotSection<ELFT> &GotSec;
+  const OutputSection<ELFT> *BssSec = nullptr;
 };
 
 template <bool Is64Bits>
diff --git a/lld/ELF/Symbols.h b/lld/ELF/Symbols.h
index d9f89255d37a..f6cd077751c1 100644
--- a/lld/ELF/Symbols.h
+++ b/lld/ELF/Symbols.h
@@ -189,8 +189,6 @@ public:
 
   // The maximum alignment we have seen for this symbol.
   uintX_t MaxAlignment;
-
-  OutputSection<ELFT> *OutputSec = nullptr;
 };
 
 // Regular defined symbols read from object file symbol tables.
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 57180df89933..58ad5ac81ee7 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -365,6 +365,11 @@ template <class ELFT> void Writer<ELFT>::createSections() {
   }
 
   BSSSec = getSection(".bss", SHT_NOBITS, SHF_ALLOC | SHF_WRITE);
+
+  // The only type in OutputSections is currently OutputSection.
+  for (OutputSectionBase<ELFT::Is64Bits> *OSB : OutputSections)
+    static_cast<OutputSection<ELFT> *>(OSB)->setBssSec(BSSSec);
+
   SymTabSec.setBssSec(BSSSec);
   DynSymSec.setBssSec(BSSSec);
 
@@ -376,7 +381,6 @@ template <class ELFT> void Writer<ELFT>::createSections() {
     uintX_t Align = C->MaxAlignment;
     Off = RoundUpToAlignment(Off, Align);
     C->OffsetInBSS = Off;
-    C->OutputSec = BSSSec;
     Off += Sym.st_size;
   }