[Object] Add symbol attribute flags: ST_ThreadLocal, ST_Common, and ST_Undefined. Implement these completely for ELF.

Rename ST_External to ST_Unknown, and slightly change its semantics. It now only indicates that the symbol's type
is unknown, not that the symbol is undefined. (For that, use ST_Undefined).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151696 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Object/ELF.h

@@ -625,12 +625,10 @@ error_code ELFObjectFile<target_endianness, is64Bits>
   validateSymbol(Symb);
   const Elf_Sym  *symb = getSymbol(Symb);
 
-  if (getSymbolTableIndex(symb) == ELF::SHN_UNDEF) {
-    Result = SymbolRef::ST_External;
-    return object_error::success;
-  }
-
   switch (symb->getType()) {
+  case ELF::STT_NOTYPE:
+    Result = SymbolRef::ST_Unknown;
+    break;
   case ELF::STT_SECTION:
     Result = SymbolRef::ST_Debug;
     break;
@@ -641,6 +639,8 @@ error_code ELFObjectFile<target_endianness, is64Bits>
     Result = SymbolRef::ST_Function;
     break;
   case ELF::STT_OBJECT:
+  case ELF::STT_COMMON:
+  case ELF::STT_TLS:
     Result = SymbolRef::ST_Data;
     break;
   default:
@@ -672,6 +672,16 @@ error_code ELFObjectFile<target_endianness, is64Bits>
       symb->getType() == ELF::STT_SECTION)
     Result |= SymbolRef::SF_FormatSpecific;
 
+  if (getSymbolTableIndex(symb) == ELF::SHN_UNDEF)
+    Result |= SymbolRef::SF_Undefined;
+
+  if (symb->getType() == ELF::STT_COMMON ||
+      getSymbolTableIndex(symb) == ELF::SHN_COMMON)
+    Result |= SymbolRef::SF_Common;
+
+  if (symb->getType() == ELF::STT_TLS)
+    Result |= SymbolRef::SF_ThreadLocal;
+
   return object_error::success;
 }
 

include/llvm/Object/ObjectFile.h

@@ -180,9 +180,9 @@ public:
   }
 
   enum Type {
+    ST_Unknown, // Type not specified
     ST_Data,
     ST_Debug,
-    ST_External,    // Defined in another object file
     ST_File,
     ST_Function,
     ST_Other
@@ -190,11 +190,14 @@ public:
 
   enum Flags {
     SF_None            = 0,
-    SF_Global          = 1 << 0, // Global symbol
+    SF_Undefined       = 1U << 0,  // Symbol is defined in another object file
-    SF_Weak            = 1 << 1, // Weak symbol
+    SF_Global          = 1U << 1,  // Global symbol
-    SF_Absolute        = 1 << 2, // Absolute symbol
+    SF_Weak            = 1U << 2,  // Weak symbol
-    SF_FormatSpecific  = 1 << 3  // Specific to the object file format
+    SF_Absolute        = 1U << 3,  // Absolute symbol
-                                 // (e.g. section symbols)
+    SF_ThreadLocal     = 1U << 4,  // Thread local symbol
+    SF_Common          = 1U << 5,  // Symbol has common linkage
+    SF_FormatSpecific  = 1U << 31  // Specific to the object file format
+                                   // (e.g. section symbols)
   };
 
   SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner);

lib/Object/COFFObjectFile.cpp

@@ -143,7 +143,7 @@ error_code COFFObjectFile::getSymbolType(DataRefImpl Symb,
   Result = SymbolRef::ST_Other;
   if (symb->StorageClass == COFF::IMAGE_SYM_CLASS_EXTERNAL &&
       symb->SectionNumber == COFF::IMAGE_SYM_UNDEFINED) {
-    Result = SymbolRef::ST_External;
+    Result = SymbolRef::ST_Unknown;
   } else {
     if (symb->getComplexType() == COFF::IMAGE_SYM_DTYPE_FUNCTION) {
       Result = SymbolRef::ST_Function;
@@ -164,7 +164,11 @@ error_code COFFObjectFile::getSymbolFlags(DataRefImpl Symb,
   const coff_symbol *symb = toSymb(Symb);
   Result = SymbolRef::SF_None;
 
-  // TODO: Set SF_FormatSpecific.
+  // TODO: Correctly set SF_FormatSpecific, SF_ThreadLocal, SF_Common
+
+  if (symb->StorageClass == COFF::IMAGE_SYM_CLASS_EXTERNAL &&
+      symb->SectionNumber == COFF::IMAGE_SYM_UNDEFINED)
+    Result |= SymbolRef::SF_Undefined;
 
   // TODO: This are certainly too restrictive.
   if (symb->StorageClass == COFF::IMAGE_SYM_CLASS_EXTERNAL)

lib/Object/MachOObjectFile.cpp

@@ -278,7 +278,12 @@ error_code MachOObjectFile::getSymbolFlags(DataRefImpl DRI,
     MachOType = Entry->Type;
   }
 
+  // TODO: Correctly set SF_ThreadLocal and SF_Common.
   Result = SymbolRef::SF_None;
+
+  if ((MachOType & MachO::NlistMaskType) == MachO::NListTypeUndefined)
+    Result |= SymbolRef::SF_Undefined;
+
   if (MachOFlags & macho::STF_StabsEntryMask)
     Result |= SymbolRef::SF_FormatSpecific;
 
@@ -337,7 +342,7 @@ error_code MachOObjectFile::getSymbolType(DataRefImpl Symb,
 
   switch (n_type & MachO::NlistMaskType) {
     case MachO::NListTypeUndefined :
-      Res = SymbolRef::ST_External;
+      Res = SymbolRef::ST_Unknown;
       break;
     case MachO::NListTypeSection :
       Res = SymbolRef::ST_Function;
@@ -554,7 +559,7 @@ error_code MachOObjectFile::sectionContainsSymbol(DataRefImpl Sec,
                                                   bool &Result) const {
   SymbolRef::Type ST;
   getSymbolType(Symb, ST);
-  if (ST == SymbolRef::ST_External) {
+  if (ST == SymbolRef::ST_Unknown) {
     Result = false;
     return object_error::success;
   }

tools/llvm-objdump/llvm-objdump.cpp

@@ -502,7 +502,7 @@ static void PrintSymbolTable(const ObjectFile *o) {
       if (Size == UnknownAddressOrSize)
         Size = 0;
       char GlobLoc = ' ';
-      if (Type != SymbolRef::ST_External)
+      if (Type != SymbolRef::ST_Unknown)
         GlobLoc = Global ? 'g' : 'l';
       char Debug = (Type == SymbolRef::ST_Debug || Type == SymbolRef::ST_File)
                    ? 'd' : ' ';