[MC][COFF] Emit weak symbols to the correct section. Patch by Dmitry Puzirev!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167877 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 8f5d770f66518f41c2ca3adaccef4d957d3fdbf7..2ee9436fb014e483e70b5b0ce921a0b891c24eba 100644 (file)
--- a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -701,8 +701,19 @@ getCOFFSectionFlags(SectionKind K) {
 const MCSection *TargetLoweringObjectFileCOFF::
 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
                          Mangler *Mang, const TargetMachine &TM) const {
-  return getContext().getCOFFSection(GV->getSection(),
-                                     getCOFFSectionFlags(Kind),
+  int Selection = 0;
+  unsigned Characteristics = getCOFFSectionFlags(Kind);
+  SmallString<128> Name(GV->getSection().c_str());
+  if (GV->isWeakForLinker()) {
+    Selection = COFF::IMAGE_COMDAT_SELECT_ANY;
+    Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
+    MCSymbol *Sym = Mang->getSymbol(GV);
+    Name.append("$");
+    Name.append(Sym->getName().begin() + 1, Sym->getName().end());
+  }
+  return getContext().getCOFFSection(Name,
+                                     Characteristics,
+                                     Selection,
                                      Kind);
 }
 

diff --git a/test/MC/COFF/weak-symbol-section-specification.ll b/test/MC/COFF/weak-symbol-section-specification.ll
new file mode 100644 (file)
index 0000000..5049372
--- /dev/null
+++ b/test/MC/COFF/weak-symbol-section-specification.ll
@@ -0,0 +1,23 @@
+; The purpose of this test is to verify that weak linkage type is not ignored by backend,
+; if section was specialized.
+
+; RUN: llc -filetype=obj -mtriple i686-pc-win32 %s -o - | coff-dump.py | FileCheck %s
+
+@a = weak unnamed_addr constant { i32, i32, i32 } { i32 0, i32 0, i32 0}, section ".data"
+
+; CHECK:           Name                     = .data$a
+; CHECK-NEXT:      VirtualSize              = 0
+; CHECK-NEXT:      VirtualAddress           = 0
+; CHECK-NEXT:      SizeOfRawData            = {{[0-9]+}}
+; CHECK-NEXT:      PointerToRawData         = 0x{{[0-9A-F]+}}
+; CHECK-NEXT:      PointerToRelocations     = 0x0
+; CHECK-NEXT:      PointerToLineNumbers     = 0x0
+; CHECK-NEXT:      NumberOfRelocations      = 0
+; CHECK-NEXT:      NumberOfLineNumbers      = 0
+; CHECK-NEXT:      Charateristics           = 0x40401040
+; CHECK-NEXT:        IMAGE_SCN_CNT_INITIALIZED_DATA
+; CHECK-NEXT:        IMAGE_SCN_LNK_COMDAT
+; CHECK-NEXT:        IMAGE_SCN_ALIGN_8BYTES
+; CHECK-NEXT:        IMAGE_SCN_MEM_READ
+; CHECK-NEXT:      SectionData              = 
+; CHECK-NEXT:        00 00 00 00 00 00 00 00 - 00 00 00 00