From afcc62024ed3ce8f30284ab3858e3cb4d141961e Mon Sep 17 00:00:00 2001
From: Carlo Kok <ck@remobjects.com>
Date: Thu, 1 Aug 2013 18:38:14 +0000
Subject: [PATCH] Bugfix for making the DWARF debug strings and labels to code
 emitted as secrel32 instead of long opcodes (only for coff). This makes them
 debuggable with GDB.

fixes Bug 16249 - LLVM generates broken debug info on Windows

llvm-svn: 187597
---
 llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp    |  4 ++
 .../test/DebugInfo/X86/coff_relative_names.ll | 40 +++++++++++++++++++
 2 files changed, 44 insertions(+)
 create mode 100644 llvm/test/DebugInfo/X86/coff_relative_names.ll

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 748259e298a8..650acab757ef 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1416,6 +1416,10 @@ void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset,
 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
                                       unsigned Size)
   const {
+  if (MAI->needsDwarfSectionOffsetDirective()) {
+    OutStreamer.EmitCOFFSecRel32(Label);
+    return;
+  }
 
   // Emit Label+Offset (or just Label if Offset is zero)
   const MCExpr *Expr = MCSymbolRefExpr::Create(Label, OutContext);
diff --git a/llvm/test/DebugInfo/X86/coff_relative_names.ll b/llvm/test/DebugInfo/X86/coff_relative_names.ll
new file mode 100644
index 000000000000..8e46e0b177dc
--- /dev/null
+++ b/llvm/test/DebugInfo/X86/coff_relative_names.ll
@@ -0,0 +1,40 @@
+; RUN: llc -mtriple=i686-w64-mingw32 -filetype=asm -O0 < %s | FileCheck %s
+
+; CHECK:  	.secrel32 Linfo_string0
+; CHECK:  	.secrel32 Linfo_string1
+;
+; generated from:
+; clang -g -S -emit-llvm test.c -o test.ll
+; int main()
+; {
+; 	return 0;
+; }
+
+; ModuleID = 'test.c'
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f80:128:128-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32-S32"
+target triple = "i686-pc-win32"
+
+; Function Attrs: nounwind
+define i32 @main() #0 {
+entry:
+  %retval = alloca i32, align 4
+  store i32 0, i32* %retval
+  ret i32 0, !dbg !10
+}
+
+attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!9}
+
+!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.4 ", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !""} ; [ DW_TAG_compile_unit ] [C:\Projects/test.c] [DW_LANG_C99]
+!1 = metadata !{metadata !"test.c", metadata !"C:\5CProjects"}
+!2 = metadata !{i32 0}
+!3 = metadata !{metadata !4}
+!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"main", metadata !"main", metadata !"", i32 1, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 0, i1 false, i32 ()* @main, null, null, metadata !2, i32 2} ; [ DW_TAG_subprogram ] [line 1] [def] [scope 2] [main]
+!5 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ] [C:\Projects/test.c]
+!6 = metadata !{i32 786453, i32 0, i32 0, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !7, i32 0, i32 0} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!7 = metadata !{metadata !8}
+!8 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
+!9 = metadata !{i32 2, metadata !"Dwarf Version", i32 3}
+!10 = metadata !{i32 3, i32 0, metadata !4, null}