[PATCH] D137473: [vfs] Allow root paths relative to the directory of the vfsoverlay YAML file

[Haowei Wu via Phabricator via cfe-commits]

haowei added inline comments.


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Comment at: clang/test/VFS/Inputs/root-relative-overlay.yaml:4
+  'case-sensitive': false,
+  'overlay-relative': true,
+  'root-relative': 'yaml-dir',
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bnbarham wrote:
> bnbarham wrote:
> > I'd prefer a test without `overlay-relative` set to make it clear they don't depend on each other.
> There's also unit tests in `llvm/unittests/Support/VirtualFileSystemTest.cpp` that you could add to.
I need some time to patch this unit test for testing the new option.
Existing functions in this unit test file does not support defining the YAMLFilePath.

I will update this patch when I finish.


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Comment at: clang/test/VFS/Inputs/root-relative-overlay.yaml:4
+  'case-sensitive': false,
+  'overlay-relative': true,
+  'root-relative': 'yaml-dir',
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haowei wrote:
> bnbarham wrote:
> > bnbarham wrote:
> > > I'd prefer a test without `overlay-relative` set to make it clear they don't depend on each other.
> > There's also unit tests in `llvm/unittests/Support/VirtualFileSystemTest.cpp` that you could add to.
> I need some time to patch this unit test for testing the new option.
> Existing functions in this unit test file does not support defining the YAMLFilePath.
> 
> I will update this patch when I finish.
I updated the yaml file and add unit tests with overlay-relative set to true and false.


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Comment at: llvm/include/llvm/Support/VirtualFileSystem.h:660
 ///   'use-external-names': <boolean, default=true>
+///   'root-relative': <string, one of 'cwd' or 'yaml-dir', default='cwd'>
 ///   'overlay-relative': <boolean, default=false>
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bnbarham wrote:
> phosek wrote:
> > Could we make this just a boolean akin to `overlay-relative` since there are only two options (default to `false`)?
> I personally prefer being explicit here, `overlay-relative` is fairly confusing as it is.
> 
> `overlay-relative` isn't about allowing relative paths, but instead means that *all* external paths should be prefixed with the directory of the overlay. To put another way, external paths can be relative whether this is true/false, `overlay-relative` just *always* prepends the overlay path.
> 
> Could you add a comment to make it clear that this has no interaction with `overlay-relative`? If you want to add a comment to `overlay-relative` with something like the above that would also be appreciated :)
I also think `overlay-relative` is a bit misleading and it should be an enum instead of a boolean option. And it should only work if the external paths are relative instead of blindly prepend the overlay dir to every external paths. But changing this will be a breaking change so I prefer to avoid it in this patch.

I updated the descriptions.


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Comment at: llvm/include/llvm/Support/VirtualFileSystem.h:752
+  enum class RootRelativeKind {
+    /// The roots are relative to the current working directory.
+    CWD,
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bnbarham wrote:
> `to the current working directory when the overlay is created.` is maybe a little clearer to me
Added into the comments.


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Comment at: llvm/include/llvm/Support/VirtualFileSystem.h:755
+    /// The roots are relative to the directory where the YAML file locates.
+    YAMLDir
+  };
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bnbarham wrote:
> Any thoughts on something like `OverlayDir` instead?
I think OverlayDir is better.


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Comment at: llvm/lib/Support/VirtualFileSystem.cpp:1903
+        assert(!FullPath.empty() && "YAML file directory must exist");
+        sys::fs::make_absolute(FS->getYAMLFileDir(), Name);
+        Name = canonicalize(Name);
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bnbarham wrote:
> IMO both this and CWD should be using the base FS instead. VFS didn't have a CWD previously, but now that it does it doesn't really make sense to use the process wide CWD. Especially since `-working-directory` doesn't change it.
Could you clarify a bit more about the "base FS" please? I am still quite new to the LLVM VFS system.  Which API should I use to get the appropriate working directory instead of the the process wide CWD?

I avoided changing the default behavior (relative to the process's current working directory) as I am a bit concerned breaking other people's use cases. 

I looked up a bit, the value "--working-directory" will be writen into "VFS->setCurrentWorkingDirectory()" Do you think it is a better idea to use this value instead of the process current working directory? Though it would still be a behavior change for users rely on process current working directories. 


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D137473/new/

https://reviews.llvm.org/D137473