Emit global ctors into .CRT$XCU instead of .ctors on Win32. Patch by Joe Groff!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151289 91177308-0d34-0410-b5e6-96231b3b80d8

lib/MC/MCObjectFileInfo.cpp

@@ -409,12 +409,22 @@ void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                         COFF::IMAGE_SCN_MEM_READ,
                         SectionKind::getReadOnly());
-  StaticCtorSection =
-    Ctx->getCOFFSection(".ctors",
-                        COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
-                        COFF::IMAGE_SCN_MEM_READ |
-                        COFF::IMAGE_SCN_MEM_WRITE,
-                        SectionKind::getDataRel());
+  if (T.getOS() == Triple::Win32) {
+    StaticCtorSection =
+      Ctx->getCOFFSection(".CRT$XCU",
+                          COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
+                          COFF::IMAGE_SCN_MEM_READ,
+                          SectionKind::getReadOnly());
+  } else {
+    StaticCtorSection =
+      Ctx->getCOFFSection(".ctors",
+                          COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
+                          COFF::IMAGE_SCN_MEM_READ |
+                          COFF::IMAGE_SCN_MEM_WRITE,
+                          SectionKind::getDataRel());
+  }
+
+
   StaticDtorSection =
     Ctx->getCOFFSection(".dtors",
                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |

test/MC/COFF/global_ctors.ll

@@ -0,0 +1,28 @@
+; Test that global ctors are emitted into the proper COFF section for the
+; target. Mingw uses .ctors, whereas MSVC uses .CRT$XC*.
+; RUN: llc < %s -mtriple i686-pc-win32 | FileCheck %s --check-prefix WIN32 
+; RUN: llc < %s -mtriple x86_64-pc-win32 | FileCheck %s --check-prefix WIN32 
+; RUN: llc < %s -mtriple i686-pc-mingw32 | FileCheck %s --check-prefix MINGW32 
+; RUN: llc < %s -mtriple x86_64-pc-mingw32 | FileCheck %s --check-prefix MINGW32 
+
+@.str = private unnamed_addr constant [13 x i8] c"constructing\00", align 1
+@.str2 = private unnamed_addr constant [5 x i8] c"main\00", align 1
+
+@llvm.global_ctors = appending global [1 x { i32, void ()* }] [{ i32, void ()* } { i32 65535, void ()* @a_global_ctor }]
+
+declare i32 @puts(i8*)
+
+define void @a_global_ctor() nounwind {
+  %1 = call i32 @puts(i8* getelementptr inbounds ([13 x i8]* @.str, i32 0, i32 0))
+  ret void
+}
+
+define i32 @main() nounwind {
+  %1 = call i32 @puts(i8* getelementptr inbounds ([5 x i8]* @.str2, i32 0, i32 0))
+  ret i32 0
+}
+
+; WIN32: .section .CRT$XCU,"r"
+; WIN32: a_global_ctor
+; MINGW32: .section .ctors,"w"
+; MINGW32: a_global_ctor