[PATCH] [-cxx-abi microsoft] Stick zero initialized symbols into the .bss section for COFF

David Majnemer david.majnemer at gmail.com
Sun Aug 11 21:11:50 PDT 2013


Hi rnk,

We need to do two things:

- Initialize BSSSection in MCObjectFileInfo::InitCOFFMCObjectFileInfo
- Teach TargetLoweringObjectFileCOFF::SelectSectionForGlobal what to do
  with it

This fixes PR16861.

http://llvm-reviews.chandlerc.com/D1361

Files:
  lib/CodeGen/TargetLoweringObjectFileImpl.cpp
  lib/MC/MCObjectFileInfo.cpp
  test/MC/COFF/bss_section.ll

Index: lib/CodeGen/TargetLoweringObjectFileImpl.cpp
===================================================================
--- lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -771,15 +771,18 @@
   }
 
   if (Kind.isText())
-    return getTextSection();
+    return TextSection;
 
   if (Kind.isThreadLocal())
-    return getTLSDataSection();
+    return TLSDataSection;
 
-  if (Kind.isReadOnly() && ReadOnlySection != 0)
+  if (Kind.isReadOnly())
     return ReadOnlySection;
 
-  return getDataSection();
+  if (Kind.isBSS())
+    return BSSSection;
+
+  return DataSection;
 }
 
 void TargetLoweringObjectFileCOFF::
Index: lib/MC/MCObjectFileInfo.cpp
===================================================================
--- lib/MC/MCObjectFileInfo.cpp
+++ lib/MC/MCObjectFileInfo.cpp
@@ -496,6 +496,12 @@
 
 void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
   // COFF
+  BSSSection =
+    Ctx->getCOFFSection(".bss",
+                        COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
+                        COFF::IMAGE_SCN_MEM_READ |
+                        COFF::IMAGE_SCN_MEM_WRITE,
+                        SectionKind::getBSS());
   TextSection =
     Ctx->getCOFFSection(".text",
                         COFF::IMAGE_SCN_CNT_CODE |
Index: test/MC/COFF/bss_section.ll
===================================================================
--- /dev/null
+++ test/MC/COFF/bss_section.ll
@@ -0,0 +1,6 @@
+; RUN: llc -mtriple i386-pc-win32 < %s | FileCheck %s
+
+%struct.foo = type { i32, i32 }
+
+@"\01?thingy@@3Ufoo@@B" = global %struct.foo zeroinitializer, align 4
+; CHECK: .bss
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D1361.1.patch
Type: text/x-patch
Size: 1641 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20130811/d4d58c95/attachment.bin>


More information about the llvm-commits mailing list