r357610 - Bug-40323: MS ABI adding template static member in the linker directive section to make sure init function can be called before main.

Yu, Jennifer via cfe-commits cfe-commits at lists.llvm.org
Thu Apr 11 14:19:30 PDT 2019


Hi Nico,

Iet’s revert it now.  I will try to re-submit latter.
Thanks.
Jennifer

From: Nico Weber [mailto:thakis at chromium.org]
Sent: Thursday, April 11, 2019 2:04 PM
To: Yu, Jennifer <jennifer.yu at intel.com>
Cc: cfe-commits <cfe-commits at lists.llvm.org>
Subject: Re: r357610 - Bug-40323: MS ABI adding template static member in the linker directive section to make sure init function can be called before main.

Hi Jennifer,

this caused https://bugs.llvm.org/show_bug.cgi?id=41471

Do you think this is easy to fix, or should we revert for now?

Thanks,
Nico

On Wed, Apr 3, 2019 at 1:20 PM Jennifer Yu via cfe-commits <cfe-commits at lists.llvm.org<mailto:cfe-commits at lists.llvm.org>> wrote:
Author: jyu2
Date: Wed Apr  3 10:21:40 2019
New Revision: 357610

URL: http://llvm.org/viewvc/llvm-project?rev=357610&view=rev
Log:
Bug-40323: MS ABI adding template static member in the linker directive section to make sure init function can be called before main.

Added:
    cfe/trunk/test/CodeGenCXX/microsoft-abi-template-static-init.cpp
Modified:
    cfe/trunk/lib/CodeGen/CGDeclCXX.cpp

Modified: cfe/trunk/lib/CodeGen/CGDeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDeclCXX.cpp?rev=357610&r1=357609&r2=357610&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGDeclCXX.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGDeclCXX.cpp Wed Apr  3 10:21:40 2019
@@ -481,6 +481,12 @@ CodeGenModule::EmitCXXGlobalVarDeclInitF
     // minor startup time optimization.  In the MS C++ ABI, there are no guard
     // variables, so this COMDAT key is required for correctness.
     AddGlobalCtor(Fn, 65535, COMDATKey);
+    if (getTarget().getCXXABI().isMicrosoft()) {
+      // In The MS C++, MS add template static data member in the linker
+      // drective.
+      assert(COMDATKey);
+      addUsedGlobal(COMDATKey);
+    }
   } else if (D->hasAttr<SelectAnyAttr>()) {
     // SelectAny globals will be comdat-folded. Put the initializer into a
     // COMDAT group associated with the global, so the initializers get folded

Added: cfe/trunk/test/CodeGenCXX/microsoft-abi-template-static-init.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/microsoft-abi-template-static-init.cpp?rev=357610&view=auto
==============================================================================
--- cfe/trunk/test/CodeGenCXX/microsoft-abi-template-static-init.cpp (added)
+++ cfe/trunk/test/CodeGenCXX/microsoft-abi-template-static-init.cpp Wed Apr  3 10:21:40 2019
@@ -0,0 +1,57 @@
+// RUN: %clang_cc1 %s -triple=i686-pc-win32 -fms-extensions -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple=x86_64-pc-win32 -fms-extensions -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple=i686-pc-windows-msvc -fms-extensions -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple=x86_64-pc-windows-msvc -fms-extensions -emit-llvm -o - | FileCheck %s
+
+struct S {
+  S();
+  ~S();
+};
+
+template <typename T> struct __declspec(dllexport) ExportedTemplate {
+  static S s;
+};
+template <typename T> S ExportedTemplate<T>::s;
+void useExportedTemplate(ExportedTemplate<int> x) {
+  (void)x.s;
+}
+int f();
+namespace selectany_init {
+// MS don't put selectany static var in the linker directive, init routine
+// f() is not getting called if x is not referenced.
+int __declspec(selectany) x = f();
+}
+
+namespace explicit_template_instantiation {
+template <typename T> struct A { static  int x; };
+template <typename T> int A<T>::x = f();
+template struct A<int>;
+}
+
+namespace implicit_template_instantiation {
+template <typename T> struct A { static  int x; };
+template <typename T>  int A<T>::x = f();
+int g() { return A<int>::x; }
+}
+
+
+template <class T>
+struct X_ {
+  static T ioo;
+  static T init();
+};
+template <class T> T X_<T>::ioo = X_<T>::init();
+template struct X_<int>;
+
+template <class T>
+struct X {
+  static T ioo;
+  static T init();
+};
+// template specialized static data don't need in llvm.used,
+// the static init routine get call from _GLOBAL__sub_I_ routines.
+template <> int X<int>::ioo = X<int>::init();
+template struct X<int>;
+// CHECK: @llvm.global_ctors = appending global [6 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 65535, void ()* @"??__Ex at selectany_init@@YAXXZ", i8* bitcast (i32* @"?x at selectany_init@@3HA" to i8*) }, { i32, void ()*, i8* } { i32 65535, void ()* @"??__E?x@?$A at H@explicit_template_instantiation@@2HA@@YAXXZ", i8* bitcast (i32* @"?x@?$A at H@explicit_template_instantiation@@2HA" to i8*) }, { i32, void ()*, i8* } { i32 65535, void ()* @"??__E?ioo@?$X_ at H@@2HA@@YAXXZ", i8* bitcast (i32* @"?ioo@?$X_ at H@@2HA" to i8*) }, { i32, void ()*, i8* } { i32 65535, void ()* @"??__E?s@?$ExportedTemplate at H@@2US@@A@@YAXXZ", i8* getelementptr inbounds (%struct.S, %struct.S* @"?s@?$ExportedTemplate at H@@2US@@A", i32 0, i32 0) }, { i32, void ()*, i8* } { i32 65535, void ()* @"??__E?x@?$A at H@implicit_template_instantiation@@2HA@@YAXXZ", i8* bitcast (i32* @"?x@?$A at H@implicit_template_instantiation@@2HA" to i8*) }, { i32, void ()*, i8* } { i32 65535, void ()* @_GLOBAL__sub_I_microsoft_abi_template_static_init.cpp, i8* null }]
+// CHECK: @llvm.used = appending global [4 x i8*] [i8* bitcast (i32* @"?x@?$A at H@explicit_template_instantiation@@2HA" to i8*), i8* bitcast (i32* @"?ioo@?$X_ at H@@2HA" to i8*), i8* getelementptr inbounds (%struct.S, %struct.S* @"?s@?$ExportedTemplate at H@@2US@@A", i32 0, i32 0), i8* bitcast (i32* @"?x@?$A at H@implicit_template_instantiation@@2HA" to i8*)], section "llvm.metadata"
+


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