[Lldb-commits] [lldb] r187423 - Updates the DW_AT_data_member_location handlers for the LLDB DWARF plugin

[Greg Clayton]

When the value is a constant, it might make more sense to show the value with a "+<decimal>" format, so instead of:

+                    s.Printf( "0x%8.8" PRIx64, offset);

it would be:

+                    s.Printf( "+%" PRIu64, offset);

This makes it clear that the value isn't a .debug_loc offset.

In order to test this, you might be able to emit assembler using "-g -S" (for clang only) and then hand edit the assembler output to emit the right kind of DWARF. Then we could test this with clang only by checking in the assembler file and compiling it. You could then verify the offset is correct via the SBType and SBTypeMember APIs without having to run this (since the assembler would be arch specific).

Greg


On Jul 30, 2013, at 12:02 PM, "Thirumurthi, Ashok" <ashok.thirumurthi at intel.com> wrote:

> I wanted to follow-up this patch with a fix for DWARFDebugInfoEntry::DumpAttribute such as the attached patch.  However, I couldn't find a test or an LLDB command that exercises this code.  Any hints would be welcome :)
> 
> - Ashok
> 
> -----Original Message-----
> From: lldb-commits-bounces at cs.uiuc.edu [mailto:lldb-commits-bounces at cs.uiuc.edu] On Behalf Of Ashok Thirumurthi
> Sent: Tuesday, July 30, 2013 10:59 AM
> To: lldb-commits at cs.uiuc.edu
> Subject: [Lldb-commits] [lldb] r187423 - Updates the DW_AT_data_member_location handlers for the LLDB DWARF plugin
> 
> Author: athirumu
> Date: Tue Jul 30 09:58:39 2013
> New Revision: 187423
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=187423&view=rev
> Log:
> Updates the DW_AT_data_member_location handlers for the LLDB DWARF plugin to handle the case of an integer constant (DWARF 3 and later).
> 
> - Fixes tests that assert in RecordLayoutBuilder::updateExternalFieldOffset
> because LLDB was providing an external AST source with missing member offsets.
> 
> Modified:
>    lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
> 
> Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
> URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp?rev=187423&r1=187422&r2=187423&view=diff
> ==============================================================================
> --- lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp (original)
> +++ lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp Tue 
> +++ Jul 30 09:58:39 2013
> @@ -1780,6 +1780,13 @@ SymbolFileDWARF::ParseChildMembers
>                                         member_byte_offset = memberOffset.ResolveValue(NULL).UInt();
>                                     }
>                                 }
> +                                else
> +                                {
> +                                    // With DWARF 3 and later, if the value is an integer constant,
> +                                    // this form value is the offset in bytes from the beginning
> +                                    // of the containing entity. 
> +                                    member_byte_offset = form_value.Unsigned(); 
> +                                }
>                                 break;
> 
>                             case DW_AT_accessibility: accessibility = DW_ACCESS_to_AccessType (form_value.Unsigned()); break; @@ -2164,16 +2171,28 @@ SymbolFileDWARF::ParseChildMembers
>                                         member_byte_offset = memberOffset.ResolveValue(NULL).UInt();
>                                     }
>                                 }
> +                                else
> +                                {
> +                                    // With DWARF 3 and later, if the value is an integer constant,
> +                                    // this form value is the offset in bytes from the beginning
> +                                    // of the containing entity. 
> +                                    member_byte_offset = form_value.Unsigned(); 
> +                                }
>                                 break;
> 
>                             case DW_AT_accessibility:
>                                 accessibility = DW_ACCESS_to_AccessType(form_value.Unsigned());
>                                 break;
> 
> -                            case DW_AT_virtuality: is_virtual = form_value.Boolean(); break;
> -                            default:
> +                            case DW_AT_virtuality:
> +                                is_virtual = form_value.Boolean();
> +                                break;
> +                                                   
>                             case DW_AT_sibling:
>                                 break;
> +
> +                            default:
> +                                break;
>                             }
>                         }
>                     }
> @@ -2620,7 +2639,7 @@ SymbolFileDWARF::ResolveClangOpaqueTypeD
>         assert(false && "not a forward clang type decl!");
>         break;
>     }
> -    return NULL;
> +    return false;
> }
> 
> Type*
> 
> 
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