llvm-project/clang
Bruno Cardoso Lopes ecf7d15d49 [VFS] Reconstruct the VFS overlay tree for more accurate lookup
The way we currently build the internal VFS overlay representation leads
to inefficient path search and might yield wrong answers when asked for
recursive or regular directory iteration.

Currently, when reading an YAML file, each YAML root entry is placed
inside a new root in the filesystem overlay. In the crash reproducer, a
simple "@import Foundation" currently maps to 43 roots, and when looking
up paths, we traverse a directory tree for each of these different
roots, until we find a match (or don't). This has two consequences:

- It's slow.
- Directory iteration gives incomplete results since it only return
results within one root - since contents of the same directory can be
declared inside different roots, the result isn't accurate.

This is in part fault of the way we currently write out the YAML file
when emitting the crash reproducer - we could generate only one root and
that would make it fast and correct again. However, we should not rely
on how the client writes the YAML, but provide a good internal
representation regardless.

This patch builds a proper virtual directory tree out of the YAML
representation, allowing faster search and proper iteration. Besides the
crash reproducer, this potentially benefits other VFS clients.

llvm-svn: 269100
2016-05-10 18:43:00 +00:00
..
INPUTS
bindings Enable support for __float128 in Clang and enable it on pertinent platforms 2016-05-09 08:52:33 +00:00
cmake [cmake] Enable zlib support for Apple stage2 builds 2016-05-09 18:40:09 +00:00
docs More fixes to codeblock formatting in documentation. 2016-05-06 16:48:29 +00:00
examples AnnotateFunctions: Tweak for mingw. 2016-04-04 15:30:44 +00:00
include Remove unused diagnostic. NFC. 2016-05-10 14:04:34 +00:00
lib [VFS] Reconstruct the VFS overlay tree for more accurate lookup 2016-05-10 18:43:00 +00:00
runtime [CMake] Pass LLVM_LIBDIR_SUFFIX into Compiler-RT 2016-05-10 16:10:22 +00:00
test [WebAssembly] Reduce strictness of static destructor test 2016-05-10 18:35:31 +00:00
tools Enable support for __float128 in Clang and enable it on pertinent platforms 2016-05-09 08:52:33 +00:00
unittests [VFS] Reconstruct the VFS overlay tree for more accurate lookup 2016-05-10 18:43:00 +00:00
utils Revert unnecessary tblgen change. 2016-04-27 20:49:44 +00:00
www [www][analyzer] Update recommended suppression mechanism for localization. 2016-05-06 18:13:30 +00:00
.arcconfig
.clang-format
.clang-tidy Try to use readability-identifier-naming check on Clang. 2016-04-13 08:59:49 +00:00
.gitignore Add the clang debug info test directory to .gitignore as it's managed separately. 2016-01-29 01:35:55 +00:00
CMakeLists.txt [CMake] On Darwin bootstrap LTO builds set DYLD_LIBRARY_PATH instead of using llvm-ar 2016-04-27 18:52:48 +00:00
CODE_OWNERS.TXT Added Anastasia Stulova as a code owner for OpenCL 2016-02-03 18:51:19 +00:00
INSTALL.txt Honor system specific paths of MAN pages 2015-11-20 18:49:02 +00:00
LICENSE.TXT Update copyright year to 2016. 2016-03-30 22:38:44 +00:00
ModuleInfo.txt
NOTES.txt
README.txt

README.txt

//===----------------------------------------------------------------------===//
// C Language Family Front-end
//===----------------------------------------------------------------------===//

Welcome to Clang.  This is a compiler front-end for the C family of languages
(C, C++, Objective-C, and Objective-C++) which is built as part of the LLVM
compiler infrastructure project.

Unlike many other compiler frontends, Clang is useful for a number of things
beyond just compiling code: we intend for Clang to be host to a number of
different source-level tools.  One example of this is the Clang Static Analyzer.

If you're interested in more (including how to build Clang) it is best to read
the relevant web sites.  Here are some pointers:

Information on Clang:              http://clang.llvm.org/
Building and using Clang:          http://clang.llvm.org/get_started.html
Clang Static Analyzer:             http://clang-analyzer.llvm.org/
Information on the LLVM project:   http://llvm.org/

If you have questions or comments about Clang, a great place to discuss them is
on the Clang development mailing list:
  http://lists.llvm.org/mailman/listinfo/cfe-dev

If you find a bug in Clang, please file it in the LLVM bug tracker:
  http://llvm.org/bugs/