From 12504649dc66c0d5cfc2dccc7d3c5e65649a65f7 Mon Sep 17 00:00:00 2001
From: Rui Ueyama <ruiu@google.com>
Date: Tue, 27 Oct 2015 21:51:13 +0000
Subject: [PATCH] ELF2: Move some code from MarkLive.cpp to InputSection.cpp.

This function is useful for ICF, so move that to a common place.

llvm-svn: 251455
---
 lld/ELF/InputSection.cpp | 22 +++++++++++++++++++++
 lld/ELF/InputSection.h   |  6 ++++++
 lld/ELF/MarkLive.cpp     | 41 +++++++++++++---------------------------
 3 files changed, 41 insertions(+), 28 deletions(-)

diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
index 60b854652ab8..1528dc5853dc 100644
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -49,6 +49,28 @@ InputSectionBase<ELFT>::getOffset(const Elf_Sym &Sym) {
   return cast<MergeInputSection<ELFT>>(this)->getOffset(Sym.st_value);
 }
 
+// Returns a section that Rel relocation is pointing to.
+template <class ELFT>
+InputSectionBase<ELFT> *
+InputSectionBase<ELFT>::getRelocTarget(const Elf_Rel &Rel) {
+  // Global symbol
+  uint32_t SymIndex = Rel.getSymbol(Config->Mips64EL);
+  if (SymbolBody *B = File->getSymbolBody(SymIndex))
+    if (auto *D = dyn_cast<DefinedRegular<ELFT>>(B->repl()))
+      return &D->Section;
+  // Local symbol
+  if (const Elf_Sym *Sym = File->getLocalSymbol(SymIndex))
+    if (InputSectionBase<ELFT> *Sec = File->getSection(*Sym))
+      return Sec;
+  return nullptr;
+}
+
+template <class ELFT>
+InputSectionBase<ELFT> *
+InputSectionBase<ELFT>::getRelocTarget(const Elf_Rela &Rel) {
+  return getRelocTarget(reinterpret_cast<const Elf_Rel &>(Rel));
+}
+
 template <class ELFT>
 InputSection<ELFT>::InputSection(ObjectFile<ELFT> *F, const Elf_Shdr *Header)
     : InputSectionBase<ELFT>(F, Header, Base::Regular) {}
diff --git a/lld/ELF/InputSection.h b/lld/ELF/InputSection.h
index 36d89a7da1ae..2e245cac193e 100644
--- a/lld/ELF/InputSection.h
+++ b/lld/ELF/InputSection.h
@@ -24,6 +24,8 @@ template <class ELFT> class OutputSectionBase;
 // This corresponds to a section of an input file.
 template <class ELFT> class InputSectionBase {
 protected:
+  typedef typename llvm::object::ELFFile<ELFT>::Elf_Rel Elf_Rel;
+  typedef typename llvm::object::ELFFile<ELFT>::Elf_Rela Elf_Rela;
   typedef typename llvm::object::ELFFile<ELFT>::Elf_Shdr Elf_Shdr;
   typedef typename llvm::object::ELFFile<ELFT>::Elf_Sym Elf_Sym;
   typedef typename llvm::object::ELFFile<ELFT>::uintX_t uintX_t;
@@ -63,6 +65,10 @@ public:
 
   uintX_t getOffset(const Elf_Sym &Sym);
   ArrayRef<uint8_t> getSectionData() const;
+
+  // Returns a section that Rel is pointing to. Used by the garbage collector.
+  InputSectionBase<ELFT> *getRelocTarget(const Elf_Rel &Rel);
+  InputSectionBase<ELFT> *getRelocTarget(const Elf_Rela &Rel);
 };
 
 template <class ELFT>
diff --git a/lld/ELF/MarkLive.cpp b/lld/ELF/MarkLive.cpp
index db411530a681..7e73a1fd78e6 100644
--- a/lld/ELF/MarkLive.cpp
+++ b/lld/ELF/MarkLive.cpp
@@ -37,40 +37,25 @@ using namespace llvm::object;
 using namespace lld;
 using namespace lld::elf2;
 
-template <class ELFT, bool isRela>
-static void
-doForEachSuccessor(InputSectionBase<ELFT> *Sec,
-                   std::function<void(InputSectionBase<ELFT> *)> Fn,
-                   iterator_range<const Elf_Rel_Impl<ELFT, isRela> *> Rels) {
-  typedef typename ELFFile<ELFT>::Elf_Sym Elf_Sym;
-  typedef Elf_Rel_Impl<ELFT, isRela> RelType;
-
-  ObjectFile<ELFT> *File = Sec->getFile();
-  for (const RelType &RI : Rels) {
-    // Global symbol
-    uint32_t SymIndex = RI.getSymbol(Config->Mips64EL);
-    if (SymbolBody *B = File->getSymbolBody(SymIndex)) {
-      if (auto *D = dyn_cast<DefinedRegular<ELFT>>(B->repl()))
-        Fn(&D->Section);
-      continue;
-    }
-    // Local symbol
-    if (const Elf_Sym *Sym = File->getLocalSymbol(SymIndex))
-      if (InputSectionBase<ELFT> *Sec = File->getSection(*Sym))
-        Fn(Sec);
-  }
-}
-
 // Calls Fn for each section that Sec refers to.
 template <class ELFT>
 static void forEachSuccessor(InputSection<ELFT> *Sec,
                              std::function<void(InputSectionBase<ELFT> *)> Fn) {
+  typedef typename ELFFile<ELFT>::Elf_Rel Elf_Rel;
+  typedef typename ELFFile<ELFT>::Elf_Rela Elf_Rela;
   typedef typename ELFFile<ELFT>::Elf_Shdr Elf_Shdr;
+
+  ELFFile<ELFT> &Obj = Sec->getFile()->getObj();
   for (const Elf_Shdr *RelSec : Sec->RelocSections) {
-    if (RelSec->sh_type == SHT_RELA)
-      doForEachSuccessor(Sec, Fn, Sec->getFile()->getObj().relas(RelSec));
-    else
-      doForEachSuccessor(Sec, Fn, Sec->getFile()->getObj().rels(RelSec));
+    if (RelSec->sh_type == SHT_RELA) {
+      for (const Elf_Rela &RI : Obj.relas(RelSec))
+        if (InputSectionBase<ELFT> *Succ = Sec->getRelocTarget(RI))
+          Fn(Succ);
+    } else {
+      for (const Elf_Rel &RI : Obj.rels(RelSec))
+        if (InputSectionBase<ELFT> *Succ = Sec->getRelocTarget(RI))
+          Fn(Succ);
+    }
   }
 }