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d-saoc-2021-03.md (2693B)


      1 ---
      2 title: 'SAOC LLDB D integration: 3rd Weekly Update'
      3 date: '2021-10-06T21:07:00+01:00'
      4 tags: ['saoc', 'saoc2021', 'dlang', 'llvm', 'lldb', 'debug', 'debugging', 'dwarf']
      5 description: "This post describes what I've done on the 3rd week of the
      6 Symmetry Autumn of Code 2021, including restructuring the patch history by
      7 splitting it up according to what LLVM team requested, bug fixes on the
      8 libiberty demangler and a small fix on DMD backend for fully qualified names on
      9 DWARF info"
     10 ---
     11 
     12 Hi D community!
     13 
     14 I'm here again, to describe what I've done during the third week of Symmetry
     15 Autumn of Code.
     16 
     17 ## Restructuring the patch history
     18 
     19 According to LLVM team, the [patch](https://reviews.llvm.org/D110576) I
     20 previously sent needs to be split into smaller ones and that is a bit of a
     21 challenge. Why you may ask? Because looking at the [ABI
     22 specification](https://dlang.org/spec/abi.html) a lot of mangling nodes are
     23 dependent of each other and splitting 3000 lines of code into small, stackable
     24 and independent patches needs some planning. I tried several layouts and
     25 [this](../../public/assets/posts/d-saoc-2021-03/split-todo.md) one seems
     26 to work out the best, so I'm sticking with it.
     27 
     28 Unfortunately, this week was kinda unproductive as I mostly spent this week
     29 entirely restructuring the patch.
     30 
     31 Because I'll only push the patches when they are done, for now, my work is on
     32 [this](https://github.com/ljmf00/llvm-project/commits/add-d-demangler-splitted)
     33 branch, although bare in mind that this will constantly change, and to fetch
     34 new changes you need to hard reset them when pulling.
     35 
     36 ## Fixing a bug on libiberty D demangler
     37 
     38 During the restructure, I found out that anonymous symbols were not correctly
     39 handled and skipped, according to the specification, so I reported a
     40 [bug](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102618) and sent a
     41 [patch](https://gcc.gnu.org/pipermail/gcc-patches/2021-October/580999.html) to
     42 fix the issue.
     43 
     44 ## Add fully qualified name on array DWARF tags
     45 
     46 This is part of the milestone 2, but since I had
     47 [this](https://github.com/dlang/dmd/pull/13120) patch archived for a long time
     48 I decided to push it on the weekend.
     49 
     50 ## What's next?
     51 
     52 Next week I hopefully finish the patch split and finally push this to the LLVM
     53 review platform. I'm also going to prepare some work for the milestone 2 that
     54 includes analyzing some DWARF info that is currently being generated by
     55 DMD/LDC/GDC compilers.
     56 
     57 You can also read this on the D programming language forum,
     58 [here](https://forum.dlang.org/thread/mailman.649.1633575050.21945.digitalmars-d@puremagic.com),
     59 and discuss there.
     60 
     61 Read about the [previous week](../d-saoc-2021-02/) and [next
     62 week](../d-saoc-2021-04/).