[llvm] r187656 - 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 (with fix for 64bits msvc)

[David Blaikie]

On Fri, Aug 2, 2013 at 11:57 AM, ck at remobjects.com <ck at remobjects.com> wrote:
> I Did actually. After this patch it could load it in both gdb 32 and 64
> without error.

Great, thanks for checking.

(though it is curious that a 32 bit special case is needed but not a
64 - not that I know much/anything about this stuff. Perhaps there's a
GDB bug to file too? (if this is a workaround for a GDB bug, a FIXME
or note saying that would be useful too))


> I want to solve further issues in separate patches
>
>
>
> ----- Reply message -----
> From: "David Blaikie" <dblaikie at gmail.com>
> To: "Carlo Kok" <ck at remobjects.com>
> Cc: "llvm-commits at cs.uiuc.edu" <llvm-commits at cs.uiuc.edu>
> Subject: [llvm] r187656 - 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 (with fix for 64bits msvc)
> Date: Fri, Aug 2, 2013 20:30
>
>
> On Fri, Aug 2, 2013 at 9:14 AM, Carlo Kok <ck at remobjects.com> wrote:
>> Author: carlokok
>> Date: Fri Aug  2 11:14:15 2013
>> New Revision: 187656
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=187656&view=rev
>> Log:
>> 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 (with fix for 64bits msvc)
>>
>> Added:
>>     llvm/trunk/test/DebugInfo/X86/coff_relative_names.ll
>> Modified:
>>     llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
>>
>> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp?rev=187656&r1=187655&r2=187656&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp (original)
>> +++ llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp Fri Aug  2 11:14:15
>> 2013
>> @@ -1416,6 +1416,10 @@ void AsmPrinter::EmitLabelOffsetDifferen
>>  void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t
>> Offset,
>>                                        unsigned Size)
>>    const {
>> +  if (MAI->needsDwarfSectionOffsetDirective() && Size == 4) { // secrel32
>> ONLY works for 32bits.
>
> Have you/could you test this for 64 bit on Windows too? Rather than
> having half an implementation leaving the next developer to ask "what
> about 64 bit?" it'd be nice to implement the complete functionality if
> possible.
>
>> +    OutStreamer.EmitCOFFSecRel32(Label);
>> +    return;
>> +  }
>>
>>    // Emit Label+Offset (or just Label if Offset is zero)
>>    const MCExpr *Expr = MCSymbolRefExpr::Create(Label, OutContext);
>>
>> Added: llvm/trunk/test/DebugInfo/X86/coff_relative_names.ll
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/coff_relative_names.ll?rev=187656&view=auto
>>
>> ==============================================================================
>> --- llvm/trunk/test/DebugInfo/X86/coff_relative_names.ll (added)
>> +++ llvm/trunk/test/DebugInfo/X86/coff_relative_names.ll Fri Aug  2
>> 11:14:15 2013
>> @@ -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}
>>
>>
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits