[PATCH] Emit initializers for selectany globals in comdat-associative sections (PR20889)

[Hans Wennborg]

Hi rnk, majnemer,

This prevents initializers for comdat-folded globals from running multiple 
times.

Please take a look!

http://reviews.llvm.org/D5281

Files:
  lib/CodeGen/CGDeclCXX.cpp
  test/CodeGenCXX/microsoft-abi-static-initializers.cpp

Index: lib/CodeGen/CGDeclCXX.cpp
===================================================================
--- lib/CodeGen/CGDeclCXX.cpp
+++ lib/CodeGen/CGDeclCXX.cpp
@@ -332,6 +332,11 @@
     // COMDAT key is required for correctness.
     AddGlobalCtor(Fn, 65535, Addr);
     DelayedCXXInitPosition.erase(D);
+  } 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 too.
+    AddGlobalCtor(Fn, 65535, Addr);
+    DelayedCXXInitPosition.erase(D);
   } else {
     llvm::DenseMap<const Decl *, unsigned>::iterator I =
       DelayedCXXInitPosition.find(D);
Index: test/CodeGenCXX/microsoft-abi-static-initializers.cpp
===================================================================
--- test/CodeGenCXX/microsoft-abi-static-initializers.cpp
+++ test/CodeGenCXX/microsoft-abi-static-initializers.cpp
@@ -1,9 +1,11 @@
 // RUN: %clang_cc1 -fms-extensions -emit-llvm %s -o - -mconstructor-aliases -triple=i386-pc-win32 | FileCheck %s
 
-// CHECK: @llvm.global_ctors = appending global [2 x { i32, void ()*, i8* }]
-// CHECK: [{ i32, void ()*, i8* } { i32 65535, void ()* @"\01??__Efoo@?$B@H@@2VA@@A@YAXXZ",
-// CHECK:       i8* bitcast (%class.A* @"\01?foo@?$B@H@@2VA@@A" to i8*) },
-// CHECK:  { i32, void ()*, i8* } { i32 65535, void ()* @_GLOBAL__sub_I_microsoft_abi_static_initializers.cpp, i8* null }]
+// CHECK: @llvm.global_ctors = appending global [4 x { i32, void ()*, i8* }] [
+// CHECK: { i32, void ()*, i8* } { i32 65535, void ()* @"\01??__Eselectany1@@YAXXZ", i8* getelementptr inbounds (%struct.S* @"\01?selectany1@@3US@@A", i32 0, i32 0) },
+// CHECK: { i32, void ()*, i8* } { i32 65535, void ()* @"\01??__Eselectany2@@YAXXZ", i8* getelementptr inbounds (%struct.S* @"\01?selectany2@@3US@@A", i32 0, i32 0) },
+// CHECK: { i32, void ()*, i8* } { i32 65535, void ()* @"\01??__Efoo@?$B@H@@2VA@@A@YAXXZ", i8* bitcast (%class.A* @"\01?foo@?$B@H@@2VA@@A" to i8*) },
+// CHECK: { i32, void ()*, i8* } { i32 65535, void ()* @_GLOBAL__sub_I_microsoft_abi_static_initializers.cpp, i8* null }
+// CHECK: ]
 
 struct S {
   S();
@@ -21,8 +23,8 @@
 // CHECK: call x86_thiscallcc void @"\01??1S@@QAE@XZ"
 // CHECK: ret void
 
-// These globals should use distinct guard variables, and not different bits of
-// the same global.
+// These globals should have initializers comdat associative with the global.
+// See @llvm.global_ctors above.
 __declspec(selectany) S selectany1;
 __declspec(selectany) S selectany2;
 // CHECK: define linkonce_odr void @"\01??__Eselectany1@@YAXXZ"()

_______________________________________________
cfe-commits mailing list
cfe-commits@cs.uiuc.edu
http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits