Fix .comm and .lcomm on COFF.

These should not use COMDATs. GNU as uses .bss for .lcomm and section 0 for
.comm.

Given

static int a;
int b;

MSVC puts both in .bss. This patch then puts both .comm and .lcomm on .bss. With
this change we agree with gas on .lcomm, are much closer on .comm and clang-cl
matches msvc on the above example.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195654 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/MC/WinCOFFStreamer.cpp b/lib/MC/WinCOFFStreamer.cpp
index 0c205e50709e3b7db8cbfd38bb7c264aa7e8fc65..af313b2ff88715eb3c1985c20d528c83f3cb736f 100644 (file)
--- a/lib/MC/WinCOFFStreamer.cpp
+++ b/lib/MC/WinCOFFStreamer.cpp
@@ -140,28 +140,12 @@ void WinCOFFStreamer::AddCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                                       unsigned ByteAlignment, bool External) {
   assert(!Symbol->isInSection() && "Symbol must not already have a section!");
 
-  std::string SectionName(".bss$linkonce");
-  SectionName.append(Symbol->getName().begin(), Symbol->getName().end());
-
-  MCSymbolData &SymbolData = getAssembler().getOrCreateSymbolData(*Symbol);
-
-  unsigned Characteristics =
-    COFF::IMAGE_SCN_LNK_COMDAT |
-    COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
-    COFF::IMAGE_SCN_MEM_READ |
-    COFF::IMAGE_SCN_MEM_WRITE;
-
-  int Selection = COFF::IMAGE_COMDAT_SELECT_LARGEST;
-
-  const MCSection *Section = MCStreamer::getContext().getCOFFSection(
-      SectionName, Characteristics, SectionKind::getBSS(), Symbol->getName(),
-      Selection);
-
+  const MCSectionCOFF *Section = getSectionBSS();
   MCSectionData &SectionData = getAssembler().getOrCreateSectionData(*Section);
-
   if (SectionData.getAlignment() < ByteAlignment)
     SectionData.setAlignment(ByteAlignment);
 
+  MCSymbolData &SymbolData = getAssembler().getOrCreateSymbolData(*Symbol);
   SymbolData.setExternal(External);
 
   AssignSection(Symbol, Section);

diff --git a/test/MC/COFF/comm.s b/test/MC/COFF/comm.s
new file mode 100644 (file)
index 0000000..21ae5d2
--- /dev/null
+++ b/test/MC/COFF/comm.s
@@ -0,0 +1,25 @@
+// RUN: llvm-mc -filetype=obj -triple i686-pc-win32 %s | llvm-readobj -t | FileCheck %s
+
+.lcomm _a,4,4
+.comm  _b, 4, 2
+
+
+// CHECK:       Symbol {
+// CHECK:         Name: _a
+// CHECK-NEXT:    Value:
+// CHECK-NEXT:    Section: .bss
+// CHECK-NEXT:    BaseType: Null
+// CHECK-NEXT:    ComplexType: Null
+// CHECK-NEXT:    StorageClass: Static
+// CHECK-NEXT:    AuxSymbolCount: 0
+// CHECK-NEXT:  }
+
+// CHECK:       Symbol {
+// CHECK:         Name: _b
+// CHECK-NEXT:    Value: 4
+// CHECK-NEXT:    Section: .bss
+// CHECK-NEXT:    BaseType: Null
+// CHECK-NEXT:    ComplexType: Null
+// CHECK-NEXT:    StorageClass: External
+// CHECK-NEXT:    AuxSymbolCount: 0
+// CHECK-NEXT:  }