Remove Size from Undefined symbol.

[ruiu]

Summary

There seems to be no reason to keep st_size of undefined symbols.
This patch removes the member for it. This patch will change outputs
in cases that undefined symbols are copied to output, but I think
this is unimportant.

[• rafael]

LGTM

lld/trunk/ELF/InputFiles.cpp

 }
 
 template <class ELFT>
 SymbolBody *elf::ObjectFile<ELFT>::createSymbolBody(const Elf_Sym *Sym) {
   unsigned char Binding = Sym->getBinding();
   InputSectionBase<ELFT> *Sec = getSection(*Sym);
   if (Binding == STB_LOCAL) {
     if (Sym->st_shndx == SHN_UNDEF)
-      return new (Alloc)
-          Undefined(Sym->st_name, Sym->st_other, Sym->getType(), Sym->st_size);
+      return new (Alloc) Undefined(Sym->st_name, Sym->st_other, Sym->getType());
     return new (Alloc) DefinedRegular<ELFT>(*Sym, Sec);
   }
 
   StringRef Name = check(Sym->getName(this->StringTable));
 
   switch (Sym->st_shndx) {
   case SHN_UNDEF:
-    return new (Alloc)
-        Undefined(Name, Binding, Sym->st_other, Sym->getType(), Sym->st_size,
+    return new (Alloc) Undefined(Name, Binding, Sym->st_other, Sym->getType(),
                                  /*IsBitcode*/ false);
   case SHN_COMMON:
     return new (Alloc) DefinedCommon(Name, Sym->st_size, Sym->st_value, Binding,
                                      Sym->st_other, Sym->getType());
   }
 
   switch (Binding) {
   default:
     fatal("unexpected binding");
   case STB_GLOBAL:
   case STB_WEAK:
   case STB_GNU_UNIQUE:
     if (Sec == &InputSection<ELFT>::Discarded)
-      return new (Alloc)
-          Undefined(Name, Binding, Sym->st_other, Sym->getType(), Sym->st_size,
+      return new (Alloc) Undefined(Name, Binding, Sym->st_other, Sym->getType(),
                                    /*IsBitcode*/ false);
     return new (Alloc) DefinedRegular<ELFT>(Name, *Sym, Sec);
   }
 }
 
 void ArchiveFile::parse() {
   File = check(Archive::create(MB), "failed to parse archive");
 
   // Allocate a buffer for Lazy objects.
else
     // FIXME: Set SF_Hidden flag correctly for module asm symbols, and expose
     // protected visibility.
     Visibility = STV_DEFAULT;
 
   if (GV)
     if (const Comdat *C = GV->getComdat())
       if (!KeptComdats.count(C)) {
         Body = new (Alloc) Undefined(NameRef, Binding, Visibility, /*Type*/ 0,
-                                     /*Size*/ 0, /*IsBitcode*/ true);
+                                     /*IsBitcode*/ true);
         return Body;
       }
 
   const Module &M = Obj.getModule();
   if (Flags & BasicSymbolRef::SF_Undefined)
     return new (Alloc) Undefined(NameRef, Binding, Visibility, /*Type*/ 0,
-                                 /*Size*/ 0, /*IsBitcode*/ true);
+                                 /*IsBitcode*/ true);
   if (Flags & BasicSymbolRef::SF_Common) {
     // FIXME: Set SF_Common flag correctly for module asm symbols, and expose
     // size and alignment.
     assert(GV);
     const DataLayout &DL = M.getDataLayout();
     uint64_t Size = DL.getTypeAllocSize(GV->getValueType());
     return new (Alloc) DefinedCommon(NameRef, Size, GV->getAlignment(), Binding,
                                      Visibility, /*Type*/ 0);

lld/trunk/ELF/SymbolTable.cpp

for (auto &IF : IFs) {
     }
     ObjectFiles.emplace_back(Obj);
   }
 }
 
 // Add an undefined symbol.
 template <class ELFT>
 SymbolBody *SymbolTable<ELFT>::addUndefined(StringRef Name) {
-  auto *Sym = new (Alloc)
-      Undefined(Name, STB_GLOBAL, STV_DEFAULT, /*Type*/ 0, /*Size*/ 0,
+  auto *Sym = new (Alloc) Undefined(Name, STB_GLOBAL, STV_DEFAULT, /*Type*/ 0,
                                     /*IsBitcode*/ false);
   resolve(Sym);
   return Sym;
 }
 
 template <class ELFT>
 DefinedRegular<ELFT> *SymbolTable<ELFT>::addAbsolute(StringRef Name,
                                                      uint8_t Visibility) {
   // Pass nullptr because absolute symbols have no corresponding input sections.

lld/trunk/ELF/Symbols.h

public:
 
   uintX_t Value;
   const OutputSectionBase<ELFT> &Section;
 };
 
 class Undefined : public SymbolBody {
 public:
   Undefined(StringRef Name, uint8_t Binding, uint8_t StOther, uint8_t Type,
-            uint64_t Size, bool IsBitcode);
-  Undefined(uint32_t NameOffset, uint8_t StOther, uint8_t Type, uint64_t Size);
-
-  uint64_t Size;
+            bool IsBitcode);
+  Undefined(uint32_t NameOffset, uint8_t StOther, uint8_t Type);
 
   static bool classof(const SymbolBody *S) {
     return S->kind() == UndefinedKind;
   }
 };
 
 template <class ELFT> class SharedSymbol : public Defined {
   typedef typename ELFT::Sym Elf_Sym;

lld/trunk/ELF/Symbols.cpp

 
 template <class ELFT> typename ELFT::uint SymbolBody::getSize() const {
   if (const auto *C = dyn_cast<DefinedCommon>(this))
     return C->Size;
   if (const auto *DR = dyn_cast<DefinedRegular<ELFT>>(this))
     return DR->Size;
   if (const auto *S = dyn_cast<SharedSymbol<ELFT>>(this))
     return S->Sym.st_size;
-  if (const auto *U = dyn_cast<Undefined>(this))
-    return U->Size;
   return 0;
 }
 
 // Returns 1, 0 or -1 if this symbol should take precedence
 // over the Other, tie or lose, respectively.
 int SymbolBody::compare(SymbolBody *Other) {
   assert(!isLazy() && !Other->isLazy());
   std::tuple<bool, bool, bool> L(isDefined(), !isShared(), !isWeak());
DefinedBitcode::DefinedBitcode(StringRef Name, bool IsWeak, uint8_t StOther)
     : Defined(DefinedBitcodeKind, Name, IsWeak ? STB_WEAK : STB_GLOBAL,
               StOther, 0 /* Type */) {}
 
 bool DefinedBitcode::classof(const SymbolBody *S) {
   return S->kind() == DefinedBitcodeKind;
 }
 
 Undefined::Undefined(StringRef Name, uint8_t Binding, uint8_t StOther,
-                     uint8_t Type, uint64_t Size, bool IsBitcode)
-    : SymbolBody(SymbolBody::UndefinedKind, Name, Binding, StOther, Type),
-      Size(Size) {
+                     uint8_t Type, bool IsBitcode)
+    : SymbolBody(SymbolBody::UndefinedKind, Name, Binding, StOther, Type) {
   this->IsUndefinedBitcode = IsBitcode;
 }
 
-Undefined::Undefined(uint32_t NameOffset, uint8_t StOther, uint8_t Type,
-                     uint64_t Size)
-    : SymbolBody(SymbolBody::UndefinedKind, NameOffset, StOther, Type),
-      Size(Size) {
+Undefined::Undefined(uint32_t NameOffset, uint8_t StOther, uint8_t Type)
+    : SymbolBody(SymbolBody::UndefinedKind, NameOffset, StOther, Type) {
   this->IsUndefinedBitcode = false;
 }
 
 template <typename ELFT>
 DefinedSynthetic<ELFT>::DefinedSynthetic(StringRef N, uintX_t Value,
                                          OutputSectionBase<ELFT> &Section)
     : Defined(SymbolBody::DefinedSyntheticKind, N, STB_GLOBAL, STV_HIDDEN,
               0 /* Type */),

lld/trunk/test/ELF/resolution.s

 // CHECK-NEXT:     Binding: Weak
 // CHECK-NEXT:     Type: None
 // CHECK-NEXT:     Other: 0
 // CHECK-NEXT:     Section: .text
 // CHECK-NEXT:   }
 // CHECK-NEXT:   Symbol {
 // CHECK-NEXT:     Name: UndefWeak_with_UndefWeak
 // CHECK-NEXT:     Value: 0x0
-// CHECK-NEXT:     Size: 15
+// CHECK-NEXT:     Size: 0
 // CHECK-NEXT:     Binding: Weak
 // CHECK-NEXT:     Type: None
 // CHECK-NEXT:     Other: 0
 // CHECK-NEXT:     Section: Undefined
 // CHECK-NEXT:   }
 // CHECK-NEXT: ]
 
 .globl _start