qiongsiwu1 added inline comments.
================
Comment at: clang/lib/Driver/ToolChains/CommonArgs.cpp:700
+ CmdArgs.push_back(Args.MakeArgString(
+ Twine(PluginOptPrefix) + "-no-integrated-as=" + NoIntegratedAs));
+ else if (!UseIntegratedAs) {
----------------
shchenz wrote:
> qiongsiwu1 wrote:
> > shchenz wrote:
> > > Seems other options leverage the default value in the back end, for
> > > example the default value for `DisableIntegratedAS` in backend is false,
> > > so when the front end requires integrated-as, maybe we can save the
> > > option here?
> > Ah thanks for the comment!
> >
> > > maybe we can save the option here?
> >
> > Could you help me understand what we mean by "the option"? Do we mean
> > saving (or using?) the value of `-f[no]-integrated-as` explicitly here
> > somehow instead of relying on `ToolChain.useIntegratedAs()`? How do we
> > intend to use the saved option value? My understanding is that
> > `DisableIntegratedAS` takes its value from the option `-no-integrated-as`
> > if `-no-integrated-as` is specified. As pointed out eariler,
> > `DisableIntegratedAS` is false by default. This code explicitly sets
> > `-no-integrated-as` to `0` or `1`, so for the LTO use case, we overwrite
> > the back end default since the option is always present.
> For example, if front-end requires to use integrated-assembler which is same
> with back-end's default value, we don't need to pass `-no-integrated-as=0`?
> We only pass the option `-no-integrated-as=1` when `if (IsOSAIX &&
> !UseIntegratedAs)`.
Ah I see! Thanks for the clarification!
@w2yehia and I discussed this and we preferred setting the option explicitly
regardless of the backend's default. The reason was that we did not want to
leave a hanging case where the option was not passed to the backend, a case in
which we would rely on a non-local option(`DisableIntegratedAS`)'s default
value to control the backend. In other words, always passing in the option
allowed us to reason about this code locally within this file. @w2yehia feel
free to chime in if I am not describing our discussion correctly.
Could you help me understand the benefit of not passing in the option for the
default case?
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D152924/new/
https://reviews.llvm.org/D152924
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