[lldb-dev] Difficulty in using target.source-map to map source files

[karnajit wangkhem via lldb-dev]

Hi All,

Below is a sample example, where target.source-map seems to have a
limitation. The limitation seems to be because
1. lldb does not have an equivalent command like directory in gdb
2. target.source-map does not accept multiple mapping entries. I checked
this only with freebsd.

(lldb) settings show target.source-map
target.source-map (path-map) =
[0] "/home/karnajitw/lldb_test_execs/test_source_line1" ->
"/u/test/test_source_line1"

3. Haven't checked in the code yet, but if we see the mappings of scenario
1, they all point to a single real path
/home/karnajitw/lldb_test_execs/test_source_line1.
But looks like the mapping logic only considers strings into account. But,
at the same time, I am not claiming that they should be interpreted as path
from a different machine during the mapping.

I want to check on this issue in-depth. But before that, want to confirm if
this is real issue or there are other ways to deal these scenarios which I
am not aware of?

I am referring below link for the lldb commands.
https://lldb.llvm.org/lldb-gdb.html

1. First scenario: Different souce file path representation

[/home/karnajitw/lldb_test_execs/test_source_line1] $ clang -O0 -g
/home/karnajitw/lldb_test_execs///test_source_line1/main.c
/home/karnajitw/lldb_test_execs/../lldb_test_execs/test_source_line1/a/ainc.c
/home/karnajitw/lldb_test_execs/test_source_line1/a/b/binc.c

Machine 1: /home/karnajitw/lldb_test_execs/test_source_line1 -> Machine 2:
/u/test/test_source_line1

test_source_line1
|-- a
|   |-- ainc.c
|   |-- ainc.h
|   `-- b
|       |-- binc.c
|       `-- binc.h
|-- a.out
`-- main.c

% ./lldb test_source_line1/a.out

(lldb) target create "test_source_line1/a.out"
Current executable set to 'test_source_line1/a.out' (x86_64).
(lldb) l main
File: /home/karnajitw/lldb_test_execs///test_source_line1/main.c
(lldb) l afn
File: /home/karnajitw/lldb_test_execs/../lldb_test_execs/test_sour
ce_line1/a/ainc.c
(lldb) l bfn
File: /home/karnajitw/lldb_test_execs/test_source_line1/a/b/binc.c

(lldb) settings set target.source-map
/home/karnajitw/lldb_test_execs///test_source_line1
/u/test/test_source_line1

(lldb) l main
File: /home/karnajitw/lldb_test_execs///test_source_line1/main.c
   1    #include "a/ainc.h"
   2
   3    int main()
   4    {
   5      afn();
   6
   7      bfn();
   8
   9      return 0;
   10   }
(lldb) l afn
File: /home/karnajitw/lldb_test_execs/../lldb_test_execs/test_sour
ce_line1/a/ainc.c
(lldb) l bfn
File: /home/karnajitw/lldb_test_execs/test_source_line1/a/b/binc.c

(lldb) settings set target.source-map /home/karnajitw/lldb_test_exec
s/../lldb_test_execs/test_source_line1 /u/test/test_source_line1

(lldb) l main
File: /home/karnajitw/lldb_test_execs///test_source_line1/main.c
(lldb) l afn
File: /home/karnajitw/lldb_test_execs/../lldb_test_execs/test_sour
ce_line1/a/ainc.c
   1    #include <stdio.h>
   2    #include "ainc.h"
   3
   4    void afn()
   5    {
   6      printf("Hello this is afn...\n");
   7    }
(lldb) l bfn
File: /home/karnajitw/lldb_test_execs/test_source_line1/a/b/binc.c

(lldb) settings set target.source-map
/home/karnajitw/lldb_test_execs/test_source_line1
/u/test/test_source_line1

(lldb) l main
File: /home/karnajitw/lldb_test_execs///test_source_line1/main.c
(lldb) l afn
File: /home/karnajitw/lldb_test_execs/../lldb_test_execs/test_sour
ce_line1/a/ainc.c
(lldb) l bfn
File: /home/karnajitw/lldb_test_execs/test_source_line1/a/b/binc.c
   1    #include <stdio.h>
   2    #include "binc.h"
   3
   4    void bfn()
   5    {
   6      printf("Hello this is bfn...\n");
   7    }

2. Scenario 2: Deep directory structure

<top>/obj/a/b/c/d/e/app/sub/../../../../../../../../src/a/b/
c/d/e/app/sub/file
<top>/obj/a/b/c/d/e/app/../../../../../../../src/a/b/c/d/e/app/file

- If we carry the copy the source file to machine 2, we cannot easily map
the source file without creating dummy <top>/obj/a/b/c/d/e/f/g.

3. Scenario 3: External libraries
- I haven't exactly tested this yet. But I belive in scenario too we might
need to change the source-map.

Please look into this and guide me for the same.

Regards,
Karan
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