Summary:
Previously only one RealFileSystem instance was available, and its working
directory is shared with the process. This doesn't work well for multithreaded
programs that want to work with relative paths - the vfs::FileSystem is assumed
to provide the working directory, but a thread cannot control this exclusively.
The new vfs::createPhysicalFileSystem() factory copies the process's working
directory initially, and then allows it to be independently modified.
This implementation records the working directory path, and glues it to relative
paths to provide the correct absolute path to the sys::fs:: functions.
This will give different results in unusual situations (e.g. the CWD is moved).
The main alternative is the use of openat(), fstatat(), etc to ask the OS to
resolve paths relative to a directory handle which can be kept open. This is
more robust. There are two reasons not to do this initially:
1. these functions are not available on all supported Unixes, and are somewhere
between difficult and unavailable on Windows. So we need a path-based
fallback anyway.
2. this would mean also adding support at the llvm::sys::fs level, which is a
larger project. My clearest idea is an OS-specific `BaseDirectory` object
that can be optionally passed to functions there. Eventually this could be
backed by either paths or a fd where openat() is supported.
This is a large project, and demonstrating here that a path-based fallback
works is a useful prerequisite.
There is some subtlety to the path-manipulation mechanism:
- when setting the working directory, both Specified=makeAbsolute(path) and
Resolved=realpath(path) are recorded. These may differ in the presence of
symlinks.
- getCurrentWorkingDirectory() and makeAbsolute() use Specified - this is
similar to the behavior of $PWD and sys::path::current_path
- IO operations like openFileForRead use Resolved. This is similar to the
behavior of an openat() based implementation, that doesn't see changes
in symlinks.
There may still be combinations of operations and FS states that yield unhelpful
behavior. This is hard to avoid with symlinks and FS abstractions :(
The caching behavior of the current working directory is removed in this patch.
getRealFileSystem() is now specified to link to the process CWD, so the caching
is incorrect.
The user who needed this so far is clangd, which will immediately switch to
createPhysicalFileSystem().
Reviewers: ilya-biryukov, bkramer, labath
Subscribers: ioeric, kadircet, kristina, llvm-commits
Differential Revision: https://reviews.llvm.org/D56545
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351050 91177308-0d34-0410-b5e6-96231b3b80d8
It fixes the case when Objective-C framework is added as a subframework
through a symlink. When parent framework infers a module map and fails
to detect a symlink, it would add a subframework as a submodule. And
when we parse module map for the subframework, we would encounter an
error like
> error: umbrella for module 'WithSubframework.Foo' already covers this directory
By implementing `getRealPath` "an egregious but useful hack" in
`ModuleMap::inferFrameworkModule` works as expected.
rdar://problem/45821279
Reviewers: bruno, benlangmuir, erik.pilkington
Reviewed By: bruno
Subscribers: hiraditya, dexonsmith, JDevlieghere, cfe-commits, llvm-commits
Differential Revision: https://reviews.llvm.org/D54245
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@347009 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r346453.
This is a complex change to a widely-used interface, and was not reviewed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@346500 91177308-0d34-0410-b5e6-96231b3b80d8
Add an optional argument to expand tildes in the path to mirror llvm's
implementation of the corresponding function.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@346453 91177308-0d34-0410-b5e6-96231b3b80d8
The "regular" file system has a useful feature that makes it possible to
stop recursing when using the recursive directory iterators. This
functionality was missing for the VFS recursive iterator and this patch
adds that.
Differential revision: https://reviews.llvm.org/D53465
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345793 91177308-0d34-0410-b5e6-96231b3b80d8
&& has higher priority than ||, so this assert works really oddly. Add
parens to match the programmer's intent.
Change-Id: I3abe1361ee0694462190c5015779db664012f3d4
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345543 91177308-0d34-0410-b5e6-96231b3b80d8
Default property value 'true' preserves current behavior. Value 'false' can be
used to create VFS "root", file system that gives better control over which
files compiler can use during compilation as there are no unpredictable
accesses to real file system.
Non-fallthrough use case changes how we treat multiple VFS overlay
files. Instead of all of them being at the same level just above a real
file system, now they are nested and subsequent overlays can refer to
files in previous overlays.
rdar://problem/39465552
Reviewers: bruno, benlangmuir
Reviewed By: bruno
Subscribers: dexonsmith, cfe-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D50539
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345431 91177308-0d34-0410-b5e6-96231b3b80d8
'ignore-non-existent-contents' stopped working after r342232 in a way
that the actual attribute value isn't used and it works as if it is
always `true`.
Common use case for VFS iteration is iterating through files in umbrella
directories for modules. Ability to detect if some VFS entries point to
non-existing files is nice but non-critical. Instead of adding back
support for `'ignore-non-existent-contents': false` I am removing the
attribute, because such scenario isn't used widely enough and stricter
checks don't provide enough value to justify the maintenance.
Change is done both in LLVM and Clang, corresponding Clang commit is r345212.
rdar://problem/45176119
Reviewers: bruno
Reviewed By: bruno
Subscribers: hiraditya, dexonsmith, sammccall, cfe-commits
Differential Revision: https://reviews.llvm.org/D53228
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345213 91177308-0d34-0410-b5e6-96231b3b80d8
This patch moves the virtual file system form clang to llvm so it can be
used by more projects.
Concretely the patch:
- Moves VirtualFileSystem.{h|cpp} from clang/Basic to llvm/Support.
- Moves the corresponding unit test from clang to llvm.
- Moves the vfs namespace from clang::vfs to llvm::vfs.
- Formats the lines affected by this change, mostly this is the result of
the added llvm namespace.
RFC on the mailing list:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/126657.html
Differential revision: https://reviews.llvm.org/D52783
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344140 91177308-0d34-0410-b5e6-96231b3b80d8
