Add support for TLS variables

If the externalized variable is Thread Local Storage (TLS), the
externalizer must flag this accordingly and the .dsc file generator
must emit the correct token for that.

Signed-off-by: Giuliano Belinassi <gbelinassi@suse.de>

Author: giulianobelinassi

libcextract/DscFileGenerator.cpp

@@ -92,6 +92,29 @@ void DscFileGenerator::Global_Functions(void)
   }
 }
 
+static bool Is_TLS(VarDecl *decl)
+{
+  return decl->getTLSKind() == VarDecl::TLS_None ? false : true;
+}
+
+static bool Is_TLS(const DeclContext::lookup_result &decls)
+{
+  bool is_tls = false;
+
+  for (auto it = decls.begin(); it != decls.end(); ++it) {
+    if (VarDecl *vdecl = dyn_cast<VarDecl>(*it)) {
+      is_tls |= Is_TLS(vdecl);
+    }
+  }
+
+  return is_tls;
+}
+
+static std::string Get_TLS_Token(bool predicate)
+{
+  return predicate == true ? "%" : "";
+}
+
 void DscFileGenerator::Local_Symbols(void)
 {
   TranslationUnitDecl *tu = AST->getASTContext().getTranslationUnitDecl();
@@ -102,9 +125,11 @@ void DscFileGenerator::Local_Symbols(void)
       DeclContext::lookup_result decls = tu->lookup(
                                           DeclarationName(&idtbl.get(entry.NewName)));
       if (decls.empty()) {
-        throw std::runtime_error("Unable to find symbol " + entry.NewName + " in the AST");
+        throw std::runtime_error("Unable to find symbol " + entry.NewName +
+				 " in the AST");
       }
-      Out << "\n#" << entry.OldName << ":" << entry.NewName;
+      Out << "\n#" << Get_TLS_Token(Is_TLS(decls)) << entry.OldName << ":" <<
+	     entry.NewName;
       std::string mod = IA.Get_Symbol_Module(entry.OldName);
       if (!mod.empty())
         Out << ":" << mod;

libcextract/SymbolExternalizer.cpp

@@ -646,6 +646,12 @@ VarDecl *SymbolExternalizer::Create_Externalized_Var(DeclaratorDecl *decl, const
     ret->addAttr(UsedAttr::Create(astctx));
   }
 
+  /* In case the original Decl has TLS storage, we must copy it to the new
+     variable as well.  */
+  if (VarDecl *vdecl = dyn_cast<VarDecl>(decl)) {
+    ret->setTSCSpec(vdecl->getTSCSpec());
+  }
+
   /* return node.  */
   return ret;
 }

testsuite/small/tls-1.c

@@ -0,0 +1,11 @@
+/* { dg-options "-DCE_EXTRACT_FUNCTIONS=set_errno -DCE_EXPORT_SYMBOLS=__libc_errno" }*/
+
+extern __thread int __libc_errno __attribute__ ((tls_model ("initial-exec")));
+
+void set_errno(int err)
+{
+  __libc_errno = err;
+}
+
+/* { dg-final { scan-tree-dump "__attribute__\(\(used\)\) static __thread int \*klpe___libc_errno;|static __thread int \*klpe___libc_errno __attribute__\(\(used\)\);" } } */
+/* { dg-final { scan-tree-dump "\(\*klpe___libc_errno\) = err" } } */