Recommit r281318 "[ELF] - Versionscript: support mangled symbols with…

… the same name."

Previouly bot was failing:
http://lab.llvm.org:8011/builders/clang-with-lto-ubuntu/builds/413/steps/test-stage1-compiler/logs/stdio
Fixed possible segfault, so commit should bix the buildbot.

Initial commit message:

This is PR30312. Info from bug page:

Both of these symbols demangle to abc::abc():
_ZN3abcC1Ev
_ZN3abcC2Ev
(These would be abc's complete object constructor and base object constructor, respectively.)
however with "abc::abc()" in the version script only one of the two receives the symbol version.

Patch fixes that.
It uses testcase created by Ed Maste (D24306).

Differential revision: https://reviews.llvm.org/D24336

llvm-svn: 281605

lld/ELF/SymbolTable.cpp

@@ -594,11 +594,12 @@ static void setVersionId(SymbolBody *Body, StringRef VersionName,
 // The relationship is 1:N instead of 1:1 because with the symbol
 // versioning, more than one symbol may have the same name.
 template <class ELFT>
-std::map<std::string, SymbolBody *> SymbolTable<ELFT>::getDemangledSyms() {
-  std::map<std::string, SymbolBody *> Result;
+std::map<std::string, std::vector<SymbolBody *>>
+SymbolTable<ELFT>::getDemangledSyms() {
+  std::map<std::string, std::vector<SymbolBody *>> Result;
   for (Symbol *Sym : SymVector) {
     SymbolBody *B = Sym->body();
-    Result[demangle(B->getName())] = B;
+    Result[demangle(B->getName())].push_back(B);
   }
   return Result;
 }
@@ -611,22 +612,24 @@ static bool hasExternCpp() {
   return false;
 }
 
-static SymbolBody *findDemangled(const std::map<std::string, SymbolBody *> &D,
-                                 StringRef Name) {
+static ArrayRef<SymbolBody *>
+findDemangled(std::map<std::string, std::vector<SymbolBody *>> &D,
+              StringRef Name) {
   auto I = D.find(Name);
   if (I != D.end())
     return I->second;
-  return nullptr;
+  return {};
 }
 
 static std::vector<SymbolBody *>
-findAllDemangled(const std::map<std::string, SymbolBody *> &D,
+findAllDemangled(const std::map<std::string, std::vector<SymbolBody *>> &D,
                  const Regex &Re) {
   std::vector<SymbolBody *> Res;
   for (auto &P : D) {
-    SymbolBody *Body = P.second;
-    if (!Body->isUndefined() && const_cast<Regex &>(Re).match(P.first))
-      Res.push_back(Body);
+    if (const_cast<Regex &>(Re).match(P.first))
+      for (SymbolBody *Body : P.second)
+        if (!Body->isUndefined())
+          Res.push_back(Body);
   }
   return Res;
 }
@@ -675,7 +678,7 @@ template <class ELFT> void SymbolTable<ELFT>::scanVersionScript() {
   // "llvm::*::foo(int, ?)". Obviously, there's no way to handle this
   // other than trying to match a regexp against all demangled symbols.
   // So, if "extern C++" feature is used, we demangle all known symbols.
-  std::map<std::string, SymbolBody *> Demangled;
+  std::map<std::string, std::vector<SymbolBody *>> Demangled;
   if (hasExternCpp())
     Demangled = getDemangledSyms();
 
@@ -685,9 +688,14 @@ template <class ELFT> void SymbolTable<ELFT>::scanVersionScript() {
     for (SymbolVersion Sym : V.Globals) {
       if (Sym.HasWildcards)
         continue;
+
       StringRef N = Sym.Name;
-      SymbolBody *B = Sym.IsExternCpp ? findDemangled(Demangled, N) : find(N);
-      setVersionId(B, V.Name, N, V.Id);
+      if (Sym.IsExternCpp) {
+        for (SymbolBody *B : findDemangled(Demangled, N))
+          setVersionId(B, V.Name, N, V.Id);
+        continue;
+      }
+      setVersionId(find(N), V.Name, N, V.Id);
     }
   }
 

lld/ELF/SymbolTable.h

@@ -101,7 +101,7 @@ template <class ELFT> class SymbolTable {
   std::string conflictMsg(SymbolBody *Existing, InputFile *NewFile);
   void reportDuplicate(SymbolBody *Existing, InputFile *NewFile);
 
-  std::map<std::string, SymbolBody *> getDemangledSyms();
+  std::map<std::string, std::vector<SymbolBody *>> getDemangledSyms();
   void handleAnonymousVersion();
 
   struct SymIndex {

lld/test/ELF/version-script-extern.s

@@ -64,11 +64,20 @@
 # DSO-NEXT:      Other: 0
 # DSO-NEXT:      Section: .text (0x6)
 # DSO-NEXT:    }
+# DSO-NEXT:    Symbol {
+# DSO-NEXT:      Name: _ZN3abcC2Ev@@LIBSAMPLE_1.0
+# DSO-NEXT:      Value: 0x1004
+# DSO-NEXT:      Size: 0
+# DSO-NEXT:      Binding: Global (0x1)
+# DSO-NEXT:      Type: Function (0x2)
+# DSO-NEXT:      Other: 0
+# DSO-NEXT:      Section: .text (0x6)
+# DSO-NEXT:    }
 # DSO-NEXT:  ]
 # DSO-NEXT:  Version symbols {
 # DSO-NEXT:    Section Name: .gnu.version
-# DSO-NEXT:    Address: 0x240
-# DSO-NEXT:    Offset: 0x240
+# DSO-NEXT:    Address: 0x258
+# DSO-NEXT:    Offset: 0x258
 # DSO-NEXT:    Link: 1
 # DSO-NEXT:    Symbols [
 # DSO-NEXT:      Symbol {
@@ -91,6 +100,10 @@
 # DSO-NEXT:        Version: 2
 # DSO-NEXT:        Name: _ZN3abcC1Ev@@LIBSAMPLE_1.0
 # DSO-NEXT:      }
+# DSO-NEXT:      Symbol {
+# DSO-NEXT:        Version: 2
+# DSO-NEXT:        Name: _ZN3abcC2Ev@@LIBSAMPLE_1.0
+# DSO-NEXT:      }
 # DSO-NEXT:    ]
 # DSO-NEXT:  }
 
@@ -114,3 +127,8 @@ retq
 .type _ZN3abcC1Ev,@function
 _ZN3abcC1Ev:
 retq
+
+.globl _ZN3abcC2Ev
+.type _ZN3abcC2Ev,@function
+_ZN3abcC2Ev:
+retq