X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FMC%2FELFObjectWriter.cpp;h=d249c92dad594557f4605331eba89ace27c9cdaa;hb=138abae2a2149b2bda3c5e28d3c4db97e3c82663;hp=72a6cbd5ef44171b4ac04031cacef4740dc6cb90;hpb=737cd213e359c2862253c3a1ee443419566e90b9;p=oota-llvm.git

diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index 72a6cbd5ef4..d249c92dad5 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -58,6 +58,14 @@ static void SetBinding(MCSymbolData &SD, unsigned Binding) {
   SD.setFlags(OtherFlags | (Binding << ELF_STB_Shift));
 }
 
+static unsigned GetVisibility(MCSymbolData &SD) {
+  unsigned Visibility =
+    (SD.getFlags() & (0xf << ELF_STV_Shift)) >> ELF_STV_Shift;
+  assert(Visibility == ELF::STV_DEFAULT || Visibility == ELF::STV_INTERNAL ||
+         Visibility == ELF::STV_HIDDEN || Visibility == ELF::STV_PROTECTED);
+  return Visibility;
+}
+
 static bool isFixupKindX86PCRel(unsigned Kind) {
   switch (Kind) {
   default:
@@ -427,11 +435,30 @@ static uint64_t SymbolValue(MCSymbolData &Data, const MCAsmLayout &Layout) {
   return 0;
 }
 
+static const MCSymbol &AliasedSymbol(const MCSymbol &Symbol) {
+  const MCSymbol *S = &Symbol;
+  while (S->isVariable()) {
+    const MCExpr *Value = S->getVariableValue();
+    assert (Value->getKind() == MCExpr::SymbolRef && "Unimplemented");
+    const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr*>(Value);
+    S = &Ref->getSymbol();
+  }
+  return *S;
+}
+
 void ELFObjectWriterImpl::WriteSymbol(MCDataFragment *F, ELFSymbolData &MSD,
                                       const MCAsmLayout &Layout) {
-  MCSymbolData &Data = *MSD.SymbolData;
-  uint8_t Info = (Data.getFlags() & 0xff);
-  uint8_t Other = ((Data.getFlags() & 0xf00) >> ELF_STV_Shift);
+  MCSymbolData &OrigData = *MSD.SymbolData;
+  MCSymbolData &Data =
+    Layout.getAssembler().getSymbolData(AliasedSymbol(OrigData.getSymbol()));
+
+  uint8_t Binding = GetBinding(OrigData);
+  uint8_t Visibility = GetVisibility(OrigData);
+  uint8_t Type = GetType(Data);
+
+  uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift);
+  uint8_t Other = Visibility;
+
   uint64_t Value = SymbolValue(Data, Layout);
   uint64_t Size = 0;
   const MCExpr *ESize;
@@ -445,12 +472,22 @@ void ELFObjectWriterImpl::WriteSymbol(MCDataFragment *F, ELFSymbolData &MSD,
       const MCBinaryExpr *BE = static_cast<const MCBinaryExpr *>(ESize);
 
       if (BE->EvaluateAsRelocatable(Res, &Layout)) {
-        MCSymbolData &A =
-          Layout.getAssembler().getSymbolData(Res.getSymA()->getSymbol());
-        MCSymbolData &B =
-          Layout.getAssembler().getSymbolData(Res.getSymB()->getSymbol());
+        uint64_t AddressA = 0;
+        uint64_t AddressB = 0;
+        const MCSymbol &SymA = Res.getSymA()->getSymbol();
+        const MCSymbol &SymB = Res.getSymB()->getSymbol();
+
+        if (SymA.isDefined()) {
+          MCSymbolData &A = Layout.getAssembler().getSymbolData(SymA);
+          AddressA = Layout.getSymbolAddress(&A);
+        }
+
+        if (SymB.isDefined()) {
+          MCSymbolData &B = Layout.getAssembler().getSymbolData(SymB);
+          AddressB = Layout.getSymbolAddress(&B);
+        }
 
-        Size = Layout.getSymbolAddress(&A) - Layout.getSymbolAddress(&B);
+        Size = AddressA - AddressB;
       }
     } else if (ESize->getKind() == MCExpr::Constant) {
       Size = static_cast<const MCConstantExpr *>(ESize)->getValue();
@@ -502,8 +539,9 @@ void ELFObjectWriterImpl::WriteSymbolTable(MCDataFragment *F,
   for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) {
     ELFSymbolData &MSD = ExternalSymbolData[i];
     MCSymbolData &Data = *MSD.SymbolData;
-    assert((Data.getFlags() & ELF_STB_Global) &&
-           "External symbol requires STB_GLOBAL flag");
+    assert(((Data.getFlags() & ELF_STB_Global) ||
+            (Data.getFlags() & ELF_STB_Weak)) &&
+           "External symbol requires STB_GLOBAL or STB_WEAK flag");
     WriteSymbol(F, MSD, Layout);
     if (GetBinding(Data) == ELF::STB_LOCAL)
       LastLocalSymbolIndex++;
@@ -519,7 +557,8 @@ void ELFObjectWriterImpl::WriteSymbolTable(MCDataFragment *F,
 }
 
 static bool ShouldRelocOnSymbol(const MCSymbolData &SD,
-                                const MCValue &Target) {
+                                const MCValue &Target,
+                                const MCFragment &F) {
   const MCSymbol &Symbol = SD.getSymbol();
   if (Symbol.isUndefined())
     return true;
@@ -527,10 +566,18 @@ static bool ShouldRelocOnSymbol(const MCSymbolData &SD,
   const MCSectionELF &Section =
     static_cast<const MCSectionELF&>(Symbol.getSection());
 
+  if (SD.isExternal())
+    return true;
+
   if (Section.getFlags() & MCSectionELF::SHF_MERGE)
     return Target.getConstant() != 0;
 
-  if (SD.isExternal())
+  MCSymbolRefExpr::VariantKind Kind = Target.getSymA()->getKind();
+  const MCSectionELF &Sec2 =
+    static_cast<const MCSectionELF&>(F.getParent()->getSection());
+
+  if (&Sec2 != &Section &&
+      (Kind == MCSymbolRefExpr::VK_PLT || Kind == MCSymbolRefExpr::VK_GOTPCREL))
     return true;
 
   return false;
@@ -550,7 +597,7 @@ void ELFObjectWriterImpl::RecordRelocation(const MCAssembler &Asm,
 
   bool IsPCRel = isFixupKindX86PCRel(Fixup.getKind());
   if (!Target.isAbsolute()) {
-    Symbol = &Target.getSymA()->getSymbol();
+    Symbol = &AliasedSymbol(Target.getSymA()->getSymbol());
     MCSymbolData &SD = Asm.getSymbolData(*Symbol);
     MCFragment *F = SD.getFragment();
 
@@ -577,7 +624,7 @@ void ELFObjectWriterImpl::RecordRelocation(const MCAssembler &Asm,
       return;
     }
 
-    bool RelocOnSymbol = ShouldRelocOnSymbol(SD, Target);
+    bool RelocOnSymbol = ShouldRelocOnSymbol(SD, Target, *Fragment);
     if (!RelocOnSymbol) {
       Index = F->getParent()->getOrdinal();
 
@@ -629,6 +676,9 @@ void ELFObjectWriterImpl::RecordRelocation(const MCAssembler &Asm,
         case MCSymbolRefExpr::VK_GOT:
           Type = ELF::R_X86_64_GOT32;
           break;
+        case llvm::MCSymbolRefExpr::VK_GOTPCREL:
+          Type = ELF::R_X86_64_GOTPCREL;
+          break;
         default:
           llvm_unreachable("Unimplemented");
         }
@@ -726,7 +776,7 @@ void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) {
 
   // Build section lookup table.
   NumRegularSections = Asm.size();
-  DenseMap<const MCSection*, uint8_t> SectionIndexMap;
+  DenseMap<const MCSection*, uint32_t> SectionIndexMap;
   unsigned Index = 1;
   for (MCAssembler::iterator it = Asm.begin(),
          ie = Asm.end(); it != ie; ++it, ++Index)
@@ -736,7 +786,7 @@ void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) {
   StringMap<uint64_t> StringIndexMap;
   StringTable += '\x00';
 
-  // Add the data for local symbols.
+  // Add the data for the symbols.
   for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
          ie = Asm.symbol_end(); it != ie; ++it) {
     const MCSymbol &Symbol = it->getSymbol();
@@ -744,76 +794,53 @@ void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) {
     if (!isInSymtab(Asm, *it, UsedInReloc.count(&Symbol)))
       continue;
 
-    if (!isLocal(*it))
-      continue;
-
-    uint64_t &Entry = StringIndexMap[Symbol.getName()];
-    if (!Entry) {
-      Entry = StringTable.size();
-      StringTable += Symbol.getName();
-      StringTable += '\x00';
-    }
-
     ELFSymbolData MSD;
     MSD.SymbolData = it;
-    MSD.StringIndex = Entry;
-
-    if (Symbol.isAbsolute()) {
-      MSD.SectionIndex = ELF::SHN_ABS;
-      LocalSymbolData.push_back(MSD);
-    } else {
-      const MCSymbol *SymbolP = &Symbol;
-      if (Symbol.isVariable()) {
-        const MCExpr *Value = Symbol.getVariableValue();
-        assert (Value->getKind() == MCExpr::SymbolRef && "Unimplemented");
-        const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr*>(Value);
-        SymbolP = &Ref->getSymbol();
-      }
-      MSD.SectionIndex = SectionIndexMap.lookup(&SymbolP->getSection());
-      assert(MSD.SectionIndex && "Invalid section index!");
-      LocalSymbolData.push_back(MSD);
-    }
-  }
-
-  // Now add non-local symbols.
-  for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
-         ie = Asm.symbol_end(); it != ie; ++it) {
-    const MCSymbol &Symbol = it->getSymbol();
-
-    if (!isInSymtab(Asm, *it, UsedInReloc.count(&Symbol)))
-      continue;
-
-    if (isLocal(*it))
-      continue;
-
-    uint64_t &Entry = StringIndexMap[Symbol.getName()];
-    if (!Entry) {
-      Entry = StringTable.size();
-      StringTable += Symbol.getName();
-      StringTable += '\x00';
-    }
-
-    ELFSymbolData MSD;
-    MSD.SymbolData = it;
-    MSD.StringIndex = Entry;
+    bool Local = isLocal(*it);
 
+    bool Add = false;
     if (it->isCommon()) {
+      assert(!Local);
       MSD.SectionIndex = ELF::SHN_COMMON;
-      ExternalSymbolData.push_back(MSD);
+      Add = true;
+    } else if (Symbol.isAbsolute()) {
+      MSD.SectionIndex = ELF::SHN_ABS;
+      Add = true;
+    } else if (Symbol.isVariable()) {
+      const MCSymbol &RefSymbol = AliasedSymbol(Symbol);
+      if (RefSymbol.isDefined()) {
+        MSD.SectionIndex = SectionIndexMap.lookup(&RefSymbol.getSection());
+        assert(MSD.SectionIndex && "Invalid section index!");
+        Add = true;
+      }
     } else if (Symbol.isUndefined()) {
+      assert(!Local);
       MSD.SectionIndex = ELF::SHN_UNDEF;
       // FIXME: Undefined symbols are global, but this is the first place we
       // are able to set it.
       if (GetBinding(*it) == ELF::STB_LOCAL)
         SetBinding(*it, ELF::STB_GLOBAL);
-      UndefinedSymbolData.push_back(MSD);
-    } else if (Symbol.isAbsolute()) {
-      MSD.SectionIndex = ELF::SHN_ABS;
-      ExternalSymbolData.push_back(MSD);
+      Add = true;
     } else {
       MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection());
       assert(MSD.SectionIndex && "Invalid section index!");
-      ExternalSymbolData.push_back(MSD);
+      Add = true;
+    }
+
+    if (Add) {
+      uint64_t &Entry = StringIndexMap[Symbol.getName()];
+      if (!Entry) {
+        Entry = StringTable.size();
+        StringTable += Symbol.getName();
+        StringTable += '\x00';
+      }
+      MSD.StringIndex = Entry;
+      if (MSD.SectionIndex == ELF::SHN_UNDEF)
+        UndefinedSymbolData.push_back(MSD);
+      else if (Local)
+        LocalSymbolData.push_back(MSD);
+      else
+        ExternalSymbolData.push_back(MSD);
     }
   }
 
@@ -1072,7 +1099,7 @@ void ELFObjectWriterImpl::WriteObject(MCAssembler &Asm,
   // ... then all of the sections ...
   DenseMap<const MCSection*, uint64_t> SectionOffsetMap;
 
-  DenseMap<const MCSection*, uint8_t> SectionIndexMap;
+  DenseMap<const MCSection*, uint32_t> SectionIndexMap;
 
   unsigned Index = 1;
   for (MCAssembler::const_iterator it = Asm.begin(),