lldb inline diagnostics print unsupported characters to Windows terminal by default

[DavidSpickett]

test.c:

int add(int n) { return 2 + n; }
int main() { return add(1); }

Compile with debug information:

C:\Users\tcwg>cl.exe test.c /Zi

Debug with lldb:

C:\Users\tcwg>llvm-worker\lldb-aarch64-windows\build\bin\lldb.exe test.exe
(lldb) target create "test.exe"
Current executable set to 'C:\Users\tcwg\test.exe' (aarch64).
(lldb) b main
Breakpoint 1: where = test.exe`main at test.c:2, address = 0x00000001400142b8
(lldb) run
Process 13376 launched: 'C:\Users\tcwg\test.exe' (aarch64)
Process 13376 stopped
* thread #1, stop reason = breakpoint 1.1
    frame #0: 0x00007ff6595a42b8 test.exe`main at test.c:2
   1    int add(int n) { return 2 + n; }
-> 2    int main() { return add(1); }

Evaluate an incorrect expression:

(lldb) p add("abc")
         ˄
         Γò░ΓöÇ error: no matching function for call to 'add'
note: note: candidate function not viable: no known conversion from 'const char[4]' to 'int' for 1st argument

This attempts to use what I think are unicode characters for curved lines, but this default Windows command prompt does not recognise them (neither does a Powershell, which is surprising).

Turning them off falls back to using just pipe characters:

(lldb) settings set show-inline-diagnostics false
(lldb) p add("abc")
error: <user expression 4>:1:1: no matching function for call to 'add'
    1 | add("abc")
      | ^~~
note: note: candidate function not viable: no known conversion from 'const char[4]' to 'int' for 1st argument

Ideally we would detect support for these characters in the terminal. I suspect the right "code page" might make this work.

[llvmbot]

@llvm/issue-subscribers-lldb

Author: David Spickett (DavidSpickett)

test.c: ``` int add(int n) { return 2 + n; } int main() { return add(1); } ``` Compile with debug information: ``` C:\Users\tcwg>cl.exe test.c /Zi ``` Debug with lldb: ``` C:\Users\tcwg>llvm-worker\lldb-aarch64-windows\build\bin\lldb.exe test.exe (lldb) target create "test.exe" Current executable set to 'C:\Users\tcwg\test.exe' (aarch64). (lldb) b main Breakpoint 1: where = test.exe`main at test.c:2, address = 0x00000001400142b8 (lldb) run Process 13376 launched: 'C:\Users\tcwg\test.exe' (aarch64) Process 13376 stopped * thread #1, stop reason = breakpoint 1.1 frame #0: 0x00007ff6595a42b8 test.exe`main at test.c:2 1 int add(int n) { return 2 + n; } -> 2 int main() { return add(1); } ``` Evaluate an incorrect expression: ``` (lldb) p add("abc") ˄ ╰─ error: no matching function for call to 'add' note: note: candidate function not viable: no known conversion from 'const char[4]' to 'int' for 1st argument ``` This attempts to use what I think are unicode characters for curved lines, but this default Windows command prompt does not recognise them (neither does a Powershell, which is surprising).

Turning them off falls back to using just pipe characters:

(lldb) settings set show-inline-diagnostics false
(lldb) p add("abc")
error: <user expression 4>:1:1: no matching function for call to 'add'
    1 | add("abc")
      | ^~~
note: note: candidate function not viable: no known conversion from 'const char[4]' to 'int' for 1st argument

Ideally we would detect support for these characters in the terminal. I suspect the right "code page" might make this work.

[DavidSpickett]

Changing the code page also fixes this:

C:\Users\tcwg>chcp 65001
Active code page: 65001

(lldb) p add("abc")
         ˄
         ╰─ error: no matching function for call to 'add'
note: note: candidate function not viable: no known conversion from 'const char[4]' to 'int' for 1st argument

We can use https://learn.microsoft.com/en-us/windows/console/getconsoleoutputcp / https://learn.microsoft.com/en-us/windows/win32/intl/code-page-identifiers to check this, unless Windows supports a Unix equivalent now.