[PATCH] D54576: [clang] - Simplify tools::SplitDebugName.

[George Rimar via Phabricator via cfe-commits]

grimar added a comment.

`SplitDebugName` is called from the following 4 places:

1. void Clang::ConstructJob()

(https://github.com/llvm-mirror/clang/blob/master/lib/Driver/ToolChains/Clang.cpp#L3933)

We can get here when clang construct jobs for regular case (cpp files):
EX: main.cpp -g -gsplit-dwarf  -o ooo

Clang by itself does not recognize the '-fdebug-compilation-dir':
clang main.cpp -g -gsplit-dwarf  -o ooo -### -fdebug-compilation-dir
clang-8: error: unknown argument: '-fdebug-compilation-dir'

So I believe this option can not be used, be in Args 
and hence affect on anything during this flow.

In other places clang constructs assembly jobs:

2. void ClangAs::ConstructJob()

(https://github.com/llvm-mirror/clang/blob/master/lib/Driver/ToolChains/Clang.cpp#L5900)

Here it tries to use the OPT_fdebug_compilation_dir option from Args:
https://github.com/llvm-mirror/clang/blob/master/lib/Driver/ToolChains/CommonArgs.cpp#L824

And this is used to construct the argument for -split-dwarf-file.

The following also would not work:
clang main.s -g -gsplit-dwarf  -o ooo -fdebug-compilation-dir,xxx
clang-8: error: unknown argument: '-fdebug-compilation-dir,xxx'

So I do not see the way to add the '-fdebug-compilation-dir' to Args here too,
so `SplitDebugName` does not use the '-fdebug-compilation-dir' I think
and its logic is dead for this case too I believe)

3, 4) These are similar:

tools::gnutools::Assembler::ConstructJob()
(https://github.com/llvm-mirror/clang/blob/master/lib/Driver/ToolChains/Gnu.cpp#L820)

tools::MinGW::Assembler::ConstructJob()
https://github.com/llvm-mirror/clang/blob/master/lib/Driver/ToolChains/MinGW.cpp#L57

Both call `SplitDebugName` to construct calls for objcopy:
https://github.com/llvm-mirror/clang/blob/master/lib/Driver/ToolChains/CommonArgs.cpp#L833

But again, `Args` for their `ConstructJob` seems can never contain the `-fdebug-compilation-dir`
I just do not see any way to achieve that.

Clang's code adds the `-fdebug-compilation-dir` by itself in `Clang::ConstructJob()` and
`ClangAs::ConstructJob()`, but it will never be used in `SplitDebugName` I think:
https://github.com/llvm-mirror/clang/blob/master/lib/Driver/ToolChains/Clang.cpp#L601
https://github.com/llvm-mirror/clang/blob/master/lib/Driver/ToolChains/Clang.cpp#L5795
https://github.com/llvm-mirror/clang/blob/master/lib/Driver/ToolChains/Clang.cpp#L4172

That `-fdebug-compilation-dir` is used in another places, not in the `SplitDebugName`
(used in invocations for -cc1 and -cc1as:
https://github.com/llvm-mirror/clang/blob/master/tools/driver/cc1as_main.cpp#L234
https://github.com/llvm-mirror/clang/blob/master/lib/Frontend/CompilerInvocation.cpp#L944)

After changes done by this patch, no check-llvm/check-clang tests started to fail for me.


https://reviews.llvm.org/D54576