Most of the cases were where a C++ file was being compiled with the C substitution.
There were a few cases of the opposite though.
LLDB seems to be the only real culprit in the LLVM codebase for these mismatches.
Rest of the LLVM presumably sticks at least language-specific options in the common substitutions
making the mistakes immediately apparent.
I found these by using Clang frontend configuration files containing language-specific options for
both C and C++ (e.g. `-std=c2y` and `-std=c++26`).
Again I think this requires DWARF. In theory we could use the PDB
file but I suspect that PDB file is in fact empty, because we
tell clang to produce DWARF.
So on Windows, first thing is we cannot run the expressions:
(lldb) expr A(); A1(); BA1(); AB();
error: <user expression 1>:1:1: 'A' has unknown return type; cast the call to its declared return type
1 | A(); A1(); BA1(); AB();
| ^~~
...and so on...
And then the AST is all unknown functions:
(lldb) image dump ast
Dumping clang ast for 4 modules.
TranslationUnitDecl 0x2b3bb591870 <<invalid sloc>> <invalid sloc> <undeserialized declarations>
|-FunctionDecl 0x2b3bb592970 <<invalid sloc>> <invalid sloc> mainCRTStartup 'unsigned long (void *)'
| `-ParmVarDecl 0x2b3bb592a20 <<invalid sloc>> <invalid sloc> 'void *'
`-FunctionDecl 0x2b3bb592ad8 <<invalid sloc>> <invalid sloc> __scrt_common_main_seh 'int ()' static
So I'm just going to disable this test on Windows, it's pretty
clear why it doesn't work and we have no plans to make it work.
Depends on https://github.com/llvm/llvm-project/pull/142163
This patch makes the `-ast-dump-filter` Clang option available to the
`target modules dump ast` command. This allows us to selectively dump
parts of the AST by name.
The AST can quickly grow way too large to skim on the console. This will
aid in debugging AST related issues.
Example:
```
(lldb) target modules dump ast --filter func
Dumping clang ast for 48 modules.
Dumping func:
FunctionDecl 0xc4b785008 <<invalid sloc>> <invalid sloc> func 'void (int)' extern
|-ParmVarDecl 0xc4b7853d8 <<invalid sloc>> <invalid sloc> x 'int'
`-AsmLabelAttr 0xc4b785358 <<invalid sloc>> Implicit "_Z4funcIiEvT_"
Dumping func<int>:
FunctionDecl 0xc4b7850b8 <<invalid sloc>> <invalid sloc> func<int> 'void (int)' implicit_instantiation extern
|-TemplateArgument type 'int'
| `-BuiltinType 0xc4b85b110 'int'
`-ParmVarDecl 0xc4b7853d8 <<invalid sloc>> <invalid sloc> x 'int'
```
The majority of this patch is adjust the `Dump` API. The main change in
behaviour is in `TypeSystemClang::Dump`, where we now use the
`ASTPrinter` for dumping the `TranslationUnitDecl`. This is where the
`-ast-dump-filter` functionality lives in Clang.
