LTO: expose LTO_SYMBOL_COMDAT flag, which indicates that the definition is part of a comdat group.

[• rafael]

With this LTO_SYMBOL_DEFINITION_WEAK will not be set if the def is in a comdat.

Given that those things are orthogonal, don't you want to make this an independent flag?

[pcc]

Make COMDAT flag orthogonal to definition

[• rafael]

Lgtm

include/llvm-c/lto.h

typedef enum {
     LTO_SYMBOL_DEFINITION_WEAK             = 0x00000300,
     LTO_SYMBOL_DEFINITION_UNDEFINED        = 0x00000400,
     LTO_SYMBOL_DEFINITION_WEAKUNDEF        = 0x00000500,
     LTO_SYMBOL_SCOPE_MASK                  = 0x00003800,
     LTO_SYMBOL_SCOPE_INTERNAL              = 0x00000800,
     LTO_SYMBOL_SCOPE_HIDDEN                = 0x00001000,
     LTO_SYMBOL_SCOPE_PROTECTED             = 0x00002000,
     LTO_SYMBOL_SCOPE_DEFAULT               = 0x00001800,
-    LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN = 0x00002800
+    LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN = 0x00002800,
+    LTO_SYMBOL_COMDAT                      = 0x00004000
 } lto_symbol_attributes;
 
 /**
  * \since prior to LTO_API_VERSION=3
  */
 typedef enum {
     LTO_DEBUG_MODEL_NONE         = 0,
     LTO_DEBUG_MODEL_DWARF        = 1

lib/LTO/LTOModule.cpp

else if (def->hasHiddenVisibility())
     attr |= LTO_SYMBOL_SCOPE_HIDDEN;
   else if (def->hasProtectedVisibility())
     attr |= LTO_SYMBOL_SCOPE_PROTECTED;
   else if (canBeOmittedFromSymbolTable(def))
     attr |= LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN;
   else
     attr |= LTO_SYMBOL_SCOPE_DEFAULT;
 
+  if (def->hasComdat())
+    attr |= LTO_SYMBOL_COMDAT;
+
   auto Iter = _defines.insert(Name).first;
 
   // fill information structure
   NameAndAttributes info;
   StringRef NameRef = Iter->first();
   info.name = NameRef.data();
   assert(info.name[NameRef.size()] == '\0');
   info.attributes = attr;