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MS ABI: Emit dynamic initializers for selectany globals in comdat-associative sections (PR20889) 

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

Differential Revision: http://reviews.llvm.org/D5281

llvm-svn: 217534
This commit is contained in:
Hans Wennborg 2014-09-10 19:28:48 +00:00
parent 1383d6f808
commit 7b556ead93
2 changed files with 25 additions and 6 deletions
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5
clang/lib/CodeGen/CGDeclCXX.cpp
View File

@ -332,6 +332,11 @@ CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
// 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);

26
clang/test/CodeGenCXX/microsoft-abi-static-initializers.cpp
View File

@ -1,9 +1,12 @@
// 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 [5 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??__Es@?$ExportedTemplate@H@@2US@@A@YAXXZ", i8* getelementptr inbounds (%struct.S* @"\01?s@?$ExportedTemplate@H@@2US@@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 +24,8 @@ S s;
// 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"()
@ -34,9 +37,20 @@ __declspec(selectany) S selectany2;
// CHECK: call x86_thiscallcc %struct.S* @"\01??0S@@QAE@XZ"
// CHECK: ret void
// The implicitly instantiated static data member should have initializer
// comdat associative with the global.
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;
}
void StaticLocal() {
static S TheS;
}
// CHECK-LABEL: define void @"\01?StaticLocal@@YAXXZ"()
// CHECK: load i32* @"\01?$S1@?0??StaticLocal@@YAXXZ@4IA"
// CHECK: store i32 {{.*}}, i32* @"\01?$S1@?0??StaticLocal@@YAXXZ@4IA"