[asan] Catch initialization-order-fiasco in modules without globals (…

…#104621)

Those modules still can have global constructors and access
globals in other modules which are not initialized yet.

compiler-rt/test/asan/TestCases/initialization-bug-no-global.cpp

@@ -1,9 +1,6 @@
 // RUN: %clangxx_asan %min_macos_deployment_target=10.11 -O0 %s %p/Helpers/initialization-bug-extra.cpp -o %t
 // RUN: %env_asan_opts=check_initialization_order=true:strict_init_order=true not %run %t 2>&1 | FileCheck %s
 
-// Not implemented.
-// XFAIL: *
-
 // Do not test with optimization -- the error may be optimized away.
 
 // FIXME: https://code.google.com/p/address-sanitizer/issues/detail?id=186

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

@@ -2531,15 +2531,10 @@ void ModuleAddressSanitizer::instrumentGlobals(IRBuilder<> &IRB, Module &M,
   SmallVector<GlobalVariable *, 16> NewGlobals(n);
   SmallVector<Constant *, 16> Initializers(n);
 
-  bool HasDynamicallyInitializedGlobals = false;
-
   // We shouldn't merge same module names, as this string serves as unique
   // module ID in runtime.
-  GlobalVariable *ModuleName =
-      n != 0
-          ? createPrivateGlobalForString(M, M.getModuleIdentifier(),
-                                         /*AllowMerging*/ false, kAsanGenPrefix)
-          : nullptr;
+  GlobalVariable *ModuleName = createPrivateGlobalForString(
+      M, M.getModuleIdentifier(), /*AllowMerging*/ false, kAsanGenPrefix);
 
   for (size_t i = 0; i < n; i++) {
     GlobalVariable *G = GlobalsToChange[i];
@@ -2646,9 +2641,6 @@ void ModuleAddressSanitizer::instrumentGlobals(IRBuilder<> &IRB, Module &M,
         Constant::getNullValue(IntptrTy),
         ConstantExpr::getPointerCast(ODRIndicator, IntptrTy));
 
-    if (ClInitializers && MD.IsDynInit)
-      HasDynamicallyInitializedGlobals = true;
-
     LLVM_DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
 
     Initializers[i] = Initializer;
@@ -2688,7 +2680,7 @@ void ModuleAddressSanitizer::instrumentGlobals(IRBuilder<> &IRB, Module &M,
   }
 
   // Create calls for poisoning before initializers run and unpoisoning after.
-  if (HasDynamicallyInitializedGlobals)
+  if (ClInitializers)
     createInitializerPoisonCalls(M, ModuleName);
 
   LLVM_DEBUG(dbgs() << M);

llvm/test/Instrumentation/AddressSanitizer/instrument_initializer_without_global.ll

@@ -18,7 +18,9 @@ define internal void @__late_ctor() sanitize_address section ".text.startup" {
 ; CHECK-LABEL: define internal void @__late_ctor(
 ; CHECK-SAME: ) #[[ATTR1:[0-9]+]] section ".text.startup" {
 ; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    call void @__asan_before_dynamic_init(i64 ptrtoint (ptr @___asan_gen_ to i64))
 ; CHECK-NEXT:    call void @initializer()
+; CHECK-NEXT:    call void @__asan_after_dynamic_init()
 ; CHECK-NEXT:    ret void
 ;
 ; NOINIT-LABEL: define internal void @__late_ctor(