[llvm-dev] LLVM Symbolizer improvements

[Fangrui Song via llvm-dev]

(Thanks David for CCing llvm-dev.)

On 2021-01-25, David Blaikie via llvm-dev wrote:
>Any particular reason for both json and yaml? Isn't one a subset of
>the other anyway?
>
>& what's the use-case? What sort of consumers do you have in mind?
>
>On Mon, Jan 25, 2021 at 12:00 PM Alex Orlov <aorlov at accesssoftek.com> wrote:
>>
>> Hello everyone,
>>
>> We are looking in to extend DIPrinter::OutputStyle { LLVM, GNU } to { LLVM, GNU, JSON, YAML }
>> and update DIPrinter to support these machine-readable printouts.
>>
>> I will propose patches shortly, unless someone has any objection.
>>
>> Thanks,
>> Alex

The output of llvm-symbolizer is line based. While some may argue that it is
brittle, in reality it has been used by several projects (e.g. pprof,
asan_symbolize.py, and various projects parsing addr2line output) in production.

If neither --output-style=GNU nor --output-style=LLVM suit your needs,
you can also try --verbose.

% llvm-symbolizer --output-style=LLVM -e Inputs/discrim 0x400590 0x400575 --verbose
foo
   Filename: /tmp/discrim.c
   Function start filename: /tmp/discrim.c
   Function start line: 4
   Line: 5
   Column: 7
main
   Filename: /tmp/discrim.c
   Function start filename: /tmp/discrim.c
   Function start line: 9
   Line: 10
   Column: 0

foo
   Filename: /tmp/discrim.c
   Function start filename: /tmp/discrim.c
   Function start line: 4
   Line: 5
   Column: 17
   Discriminator: 2

If you want more information, than the command line utility llvm-symbolizer may not suit.
You can probably use the lib/DebugInfo/Symbolize library directly.