Bugfix for making the DWARF debug strings and labels to code emitted as...

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

@@ -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);

llvm/test/DebugInfo/X86/coff_relative_names.ll

+; 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}