[ASan] Fix the test for __asan_gen_ globals and actually fix http://llvm.org/bugs/show_bug.cgi?id=17976

by setting the correct linkage (as stated in the bug).

llvm-svn: 198018

compiler-rt/lib/asan/lit_tests/TestCases/no_asan_gen_globals.c

@@ -1,7 +1,8 @@
 // Make sure __asan_gen_* strings do not end up in the symbol table.
 
 // RUN: %clang_asan %s -o %t.exe
-// RUN: nm %t.exe | grep __asan_gen_ || exit 0
+// RUN: nm %t.exe | FileCheck %s
 
 int x, y, z;
 int main() { return 0; }
+// CHECK-NOT: __asan_gen_

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

@@ -562,13 +562,13 @@ static GlobalVariable *createPrivateGlobalForString(
     Module &M, StringRef Str, bool AllowMerging) {
   Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
   // For module-local strings that can be merged with another one we set the
-  // internal linkage and the unnamed_addr attribute.
+  // private linkage and the unnamed_addr attribute.
   // Non-mergeable strings are made linker_private to remove them from the
   // symbol table. "private" linkage doesn't work for Darwin, where the
   // "L"-prefixed globals  end up in __TEXT,__const section
   // (see http://llvm.org/bugs/show_bug.cgi?id=17976 for more info).
   GlobalValue::LinkageTypes linkage =
-      AllowMerging ? GlobalValue::InternalLinkage
+      AllowMerging ? GlobalValue::PrivateLinkage
                    : GlobalValue::LinkerPrivateLinkage;
   GlobalVariable *GV =
       new GlobalVariable(M, StrConst->getType(), true,