This can happen if the input command line is barely under the limit,
but ends up exceeding it due to the extra arguments that the wrapper
adds.
One could hope that _tspawnvp would set errno to a helpful error code,
to identify the issue when printing the error with _tperror(), but in
practice, it doesn't.
This avoids inflating the total size of the command line too much.
If the input command line is near the max size of a command line
(32767 characters), it may grow past that limit when adding the
arguments injected by the wrapper. If we excessively quote all
arguments that don't need to be quoted, we can more easily run
into this situation.
Thus, by avoiding excessive quoting, we reduce the risk for this
issue to happen.
This avoids the issue reported at
https://github.com/mstorsjo/llvm-mingw/issues/296.
This allows the wrappers to invoke the right tool with the right
options, even when the wrapper was invoked with an obfuscated
short form file name.
This happens e.g. when CMake/Ninja invokes the tools from a path
that contains spaces.
Normally, we'd split the string at the last dash. However if the
tool name is "llvm-<tool>", make sure to include "llvm-" in the
tool name part when splitting the executable name.
In llvm-wrapper, don't add a duplicate "llvm-" prefix for the tool
name in these cases.
This saves a lot of diskspace, when symlinks are turned into full
copies of the tools on windows, as the symlinks only point to a small
wrapper instead of to the full tool.
Martin Storsjö