[llvm] r226217 - [Object] Add SF_Exported flag. This flag will be set on all symbols that would

[Lang Hames]

Author: lhames
Date: Thu Jan 15 16:33:30 2015
New Revision: 226217

URL: http://llvm.org/viewvc/llvm-project?rev=226217&view=rev
Log:
[Object] Add SF_Exported flag. This flag will be set on all symbols that would
be exported from a dylib if their containing object file were linked into one.

No test case: No command line tools query this flag, and there are no Object
unit tests.


Modified:
    llvm/trunk/include/llvm/Object/ELFObjectFile.h
    llvm/trunk/include/llvm/Object/SymbolicFile.h
    llvm/trunk/lib/Object/MachOObjectFile.cpp

Modified: llvm/trunk/include/llvm/Object/ELFObjectFile.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Object/ELFObjectFile.h?rev=226217&r1=226216&r2=226217&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Object/ELFObjectFile.h (original)
+++ llvm/trunk/include/llvm/Object/ELFObjectFile.h Thu Jan 15 16:33:30 2015
@@ -177,6 +177,20 @@ protected:
     return DRI;
   }
 
+  bool isExportedToOtherDSO(const Elf_Sym *ESym) const {
+    unsigned char Binding = ESym->getBinding();
+    unsigned char Visibility = ESym->getVisibility();
+
+    // A symbol is exported if its binding is either GLOBAL or WEAK, and its
+    // visibility is either DEFAULT or PROTECTED. All other symbols are not
+    // exported.
+    if ((Binding == ELF::STB_GLOBAL || Binding == ELF::STB_WEAK) &&
+        (Visibility == ELF::STV_DEFAULT && Visibility == ELF::STV_PROTECTED))
+      return true;
+
+    return false;
+  }
+
   // This flag is used for classof, to distinguish ELFObjectFile from
   // its subclass. If more subclasses will be created, this flag will
   // have to become an enum.
@@ -389,6 +403,9 @@ uint32_t ELFObjectFile<ELFT>::getSymbolF
       EF.getSymbolTableIndex(ESym) == ELF::SHN_COMMON)
     Result |= SymbolRef::SF_Common;
 
+  if (isExportedToOtherDSO(ESym))
+    Result |= SymbolRef::SF_Exported;
+
   return Result;
 }
 

Modified: llvm/trunk/include/llvm/Object/SymbolicFile.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Object/SymbolicFile.h?rev=226217&r1=226216&r2=226217&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Object/SymbolicFile.h (original)
+++ llvm/trunk/include/llvm/Object/SymbolicFile.h Thu Jan 15 16:33:30 2015
@@ -87,9 +87,10 @@ public:
     SF_Absolute = 1U << 3,       // Absolute symbol
     SF_Common = 1U << 4,         // Symbol has common linkage
     SF_Indirect = 1U << 5,       // Symbol is an alias to another symbol
-    SF_FormatSpecific = 1U << 6, // Specific to the object file format
+    SF_Exported = 1U << 6,       // Symbol is visible to other DSOs
+    SF_FormatSpecific = 1U << 7, // Specific to the object file format
                                  // (e.g. section symbols)
-    SF_Thumb = 1U << 7           // Thumb symbol in a 32-bit ARM binary
+    SF_Thumb = 1U << 8,          // Thumb symbol in a 32-bit ARM binary
   };
 
   BasicSymbolRef() : OwningObject(nullptr) { }

Modified: llvm/trunk/lib/Object/MachOObjectFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/MachOObjectFile.cpp?rev=226217&r1=226216&r2=226217&view=diff
==============================================================================
--- llvm/trunk/lib/Object/MachOObjectFile.cpp (original)
+++ llvm/trunk/lib/Object/MachOObjectFile.cpp Thu Jan 15 16:33:30 2015
@@ -478,6 +478,9 @@ uint32_t MachOObjectFile::getSymbolFlags
       if (Value && Value != UnknownAddressOrSize)
         Result |= SymbolRef::SF_Common;
     }
+
+    if (!(MachOType & MachO::N_PEXT))
+      Result |= SymbolRef::SF_Exported;
   }
 
   if (MachOFlags & (MachO::N_WEAK_REF | MachO::N_WEAK_DEF))