Implement the "linker_private_weak" linkage type. This will be used for

Objective-C metadata types which should be marked as "weak", but which the
linker will remove upon final linkage. However, this linkage isn't specific to
Objective-C.

For example, the "objc_msgSend_fixup_alloc" symbol is defined like this:

      .globl l_objc_msgSend_fixup_alloc
      .weak_definition l_objc_msgSend_fixup_alloc
      .section __DATA, __objc_msgrefs, coalesced
      .align 3
l_objc_msgSend_fixup_alloc:
       .quad   _objc_msgSend_fixup
       .quad   L_OBJC_METH_VAR_NAME_1

This is different from the "linker_private" linkage type, because it can't have
the metadata defined with ".weak_definition".

Currently only supported on Darwin platforms.

llvm-svn: 107433

1 files changed, 22 insertions, 14 deletions

diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 1cd66e536ea..67521814b0c 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -196,19 +196,20 @@ bool LLParser::ParseTopLevelEntities() {
     // optional leading prefixes, the production is:
     // GlobalVar ::= OptionalLinkage OptionalVisibility OptionalThreadLocal
     //               OptionalAddrSpace ('constant'|'global') ...
-    case lltok::kw_private :       // OptionalLinkage
-    case lltok::kw_linker_private: // OptionalLinkage
-    case lltok::kw_internal:       // OptionalLinkage
-    case lltok::kw_weak:           // OptionalLinkage
-    case lltok::kw_weak_odr:       // OptionalLinkage
-    case lltok::kw_linkonce:       // OptionalLinkage
-    case lltok::kw_linkonce_odr:   // OptionalLinkage
-    case lltok::kw_appending:      // OptionalLinkage
-    case lltok::kw_dllexport:      // OptionalLinkage
-    case lltok::kw_common:         // OptionalLinkage
-    case lltok::kw_dllimport:      // OptionalLinkage
-    case lltok::kw_extern_weak:    // OptionalLinkage
-    case lltok::kw_external: {     // OptionalLinkage
+    case lltok::kw_private:             // OptionalLinkage
+    case lltok::kw_linker_private:      // OptionalLinkage
+    case lltok::kw_linker_private_weak: // OptionalLinkage
+    case lltok::kw_internal:            // OptionalLinkage
+    case lltok::kw_weak:                // OptionalLinkage
+    case lltok::kw_weak_odr:            // OptionalLinkage
+    case lltok::kw_linkonce:            // OptionalLinkage
+    case lltok::kw_linkonce_odr:        // OptionalLinkage
+    case lltok::kw_appending:           // OptionalLinkage
+    case lltok::kw_dllexport:           // OptionalLinkage
+    case lltok::kw_common:              // OptionalLinkage
+    case lltok::kw_dllimport:           // OptionalLinkage
+    case lltok::kw_extern_weak:         // OptionalLinkage
+    case lltok::kw_external: {          // OptionalLinkage
       unsigned Linkage, Visibility;
       if (ParseOptionalLinkage(Linkage) ||
           ParseOptionalVisibility(Visibility) ||
@@ -629,7 +630,8 @@ bool LLParser::ParseAlias(const std::string &Name, LocTy NameLoc,
       Linkage != GlobalValue::WeakODRLinkage &&
       Linkage != GlobalValue::InternalLinkage &&
       Linkage != GlobalValue::PrivateLinkage &&
-      Linkage != GlobalValue::LinkerPrivateLinkage)
+      Linkage != GlobalValue::LinkerPrivateLinkage &&
+      Linkage != GlobalValue::LinkerPrivateWeakLinkage)
     return Error(LinkageLoc, "invalid linkage type for alias");
 
   Constant *Aliasee;
@@ -1013,11 +1015,13 @@ bool LLParser::ParseOptionalAttrs(unsigned &Attrs, unsigned AttrKind) {
 ///   ::= /*empty*/
 ///   ::= 'private'
 ///   ::= 'linker_private'
+///   ::= 'linker_private_weak'
 ///   ::= 'internal'
 ///   ::= 'weak'
 ///   ::= 'weak_odr'
 ///   ::= 'linkonce'
 ///   ::= 'linkonce_odr'
+///   ::= 'available_externally'
 ///   ::= 'appending'
 ///   ::= 'dllexport'
 ///   ::= 'common'
@@ -1030,6 +1034,9 @@ bool LLParser::ParseOptionalLinkage(unsigned &Res, bool &HasLinkage) {
   default:                       Res=GlobalValue::ExternalLinkage; return false;
   case lltok::kw_private:        Res = GlobalValue::PrivateLinkage;       break;
   case lltok::kw_linker_private: Res = GlobalValue::LinkerPrivateLinkage; break;
+  case lltok::kw_linker_private_weak:
+    Res = GlobalValue::LinkerPrivateWeakLinkage;
+    break;
   case lltok::kw_internal:       Res = GlobalValue::InternalLinkage;      break;
   case lltok::kw_weak:           Res = GlobalValue::WeakAnyLinkage;       break;
   case lltok::kw_weak_odr:       Res = GlobalValue::WeakODRLinkage;       break;
@@ -2704,6 +2711,7 @@ bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
     break;
   case GlobalValue::PrivateLinkage:
   case GlobalValue::LinkerPrivateLinkage:
+  case GlobalValue::LinkerPrivateWeakLinkage:
   case GlobalValue::InternalLinkage:
   case GlobalValue::AvailableExternallyLinkage:
   case GlobalValue::LinkOnceAnyLinkage: