Commit Graph

209 Commits

Author SHA1 Message Date
Arthur Eubanks 2dcad7754a [clang] Don't clear AST if we have consumers running after the main action
Downstream users may have Clang plugins. By default these plugins run
after the main action if they are specified on the command line.

Since these plugins are ASTConsumers, presumably they inspect the AST.
So we shouldn't clear it if any plugins run after the main action.

Reviewed By: dblaikie, hans

Differential Revision: https://reviews.llvm.org/D112190
2021-10-21 09:03:57 -07:00
Arthur Eubanks fe66433fe1 [clang] Add plugin ActionType to run command line plugin before main action
Currently we have a way to run a plugin if specified on the command line
after the main action, and ways to unconditionally run the plugin before
or after the main action, but no way to run a plugin if specified on the
command line before the main action.

This introduces the missing option.

This is helpful because -clear-ast-before-backend clears the AST before
codegen, while some plugins may want access to the AST.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D112096
2021-10-20 08:58:20 -07:00
Jan Svoboda 638c673a8c [clang][modules] NFC: Propagate import `SourceLocation` into `HeaderSearch::lookupModule`
This patch propagates the import `SourceLocation` into `HeaderSearch::lookupModule`. This enables remarks on search path usage (implemented in D102923) to point to the source code that initiated header search.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D111557
2021-10-12 09:31:51 +02:00
Chris Bieneman 744ec74b30 [NFC] `goto fail` has failed us in the past...
This patch replaces reliance on `goto failure` pattern with
`llvm::scope_exit`.

Reviewed By: bkramer

Differential Revision: https://reviews.llvm.org/D109865
2021-09-21 09:18:37 -05:00
Michael Spencer d3676d4b66 [clang][modules] Build inferred modules
This patch enables explicitly building inferred modules.

Effectively a cherry-pick of https://github.com/apple/llvm-project/pull/699 authored by @Bigcheese with libclang and dependency scanner changes omitted.

Contains the following changes:

1. [Clang] Fix the header paths in clang::Module for inferred modules.
  * The UmbrellaAsWritten and NameAsWritten fields in clang::Module are a lie for framework modules. For those they actually are the path to the header or umbrella relative to the clang::Module::Directory.
  * The exception to this case is for inferred modules. Here it actually is the name as written, because we print out the module and read it back in when implicitly building modules. This causes a problem when explicitly building an inferred module, as we skip the printing out step.
  * In order to fix this issue this patch adds a new field for the path we want to use in getInputBufferForModule. It also makes NameAsWritten actually be the name written in the module map file (or that would be, in the case of an inferred module).

2. [Clang] Allow explicitly building an inferred module.
  * Building the actual module still fails, but make sure it fails for the right reason.

Split from D100934.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D102491
2021-05-17 10:40:51 +02:00
Vassil Vassilev 92f9852fc9 [clang-repl] Recommit "Land initial infrastructure for incremental parsing"
Original commit message:

  In http://lists.llvm.org/pipermail/llvm-dev/2020-July/143257.html we have
  mentioned our plans to make some of the incremental compilation facilities
  available in llvm mainline.

  This patch proposes a minimal version of a repl, clang-repl, which enables
  interpreter-like interaction for C++. For instance:

  ./bin/clang-repl
  clang-repl> int i = 42;
  clang-repl> extern "C" int printf(const char*,...);
  clang-repl> auto r1 = printf("i=%d\n", i);
  i=42
  clang-repl> quit

  The patch allows very limited functionality, for example, it crashes on invalid
  C++. The design of the proposed patch follows closely the design of cling. The
  idea is to gather feedback and gradually evolve both clang-repl and cling to
  what the community agrees upon.

  The IncrementalParser class is responsible for driving the clang parser and
  codegen and allows the compiler infrastructure to process more than one input.
  Every input adds to the “ever-growing” translation unit. That model is enabled
  by an IncrementalAction which prevents teardown when HandleTranslationUnit.

  The IncrementalExecutor class hides some of the underlying implementation
  details of the concrete JIT infrastructure. It exposes the minimal set of
  functionality required by our incremental compiler/interpreter.

  The Transaction class keeps track of the AST and the LLVM IR for each
  incremental input. That tracking information will be later used to implement
  error recovery.

  The Interpreter class orchestrates the IncrementalParser and the
  IncrementalExecutor to model interpreter-like behavior. It provides the public
  API which can be used (in future) when using the interpreter library.

  Differential revision: https://reviews.llvm.org/D96033
2021-05-13 06:30:29 +00:00
Vassil Vassilev f6907152db Revert "[clang-repl] Land initial infrastructure for incremental parsing"
This reverts commit 44a4000181.

We are seeing build failures due to missing dependency to libSupport and
CMake Error at tools/clang/tools/clang-repl/cmake_install.cmake
file INSTALL cannot find
2021-05-13 04:44:19 +00:00
Vassil Vassilev 44a4000181 [clang-repl] Land initial infrastructure for incremental parsing
In http://lists.llvm.org/pipermail/llvm-dev/2020-July/143257.html we have
mentioned our plans to make some of the incremental compilation facilities
available in llvm mainline.

This patch proposes a minimal version of a repl, clang-repl, which enables
interpreter-like interaction for C++. For instance:

./bin/clang-repl
clang-repl> int i = 42;
clang-repl> extern "C" int printf(const char*,...);
clang-repl> auto r1 = printf("i=%d\n", i);
i=42
clang-repl> quit

The patch allows very limited functionality, for example, it crashes on invalid
C++. The design of the proposed patch follows closely the design of cling. The
idea is to gather feedback and gradually evolve both clang-repl and cling to
what the community agrees upon.

The IncrementalParser class is responsible for driving the clang parser and
codegen and allows the compiler infrastructure to process more than one input.
Every input adds to the “ever-growing” translation unit. That model is enabled
by an IncrementalAction which prevents teardown when HandleTranslationUnit.

The IncrementalExecutor class hides some of the underlying implementation
details of the concrete JIT infrastructure. It exposes the minimal set of
functionality required by our incremental compiler/interpreter.

The Transaction class keeps track of the AST and the LLVM IR for each
incremental input. That tracking information will be later used to implement
error recovery.

The Interpreter class orchestrates the IncrementalParser and the
IncrementalExecutor to model interpreter-like behavior. It provides the public
API which can be used (in future) when using the interpreter library.

Differential revision: https://reviews.llvm.org/D96033
2021-05-13 04:23:24 +00:00
Argyrios Kyrtzidis b0e89906f5 [ASTReader] Allow controlling separately whether validation should be disabled for a PCH vs a module file
This addresses an issue with how the PCH preable works, specifically:

1. When using a PCH/preamble the module hash changes and a different cache directory is used
2. When the preamble is used, PCH & PCM validation is disabled.

Due to combination of #1 and #2, reparsing with preamble enabled can end up loading a stale module file before a header change and using it without updating it because validation is disabled and it doesn’t check that the header has changed and the module file is out-of-date.

rdar://72611253

Differential Revision: https://reviews.llvm.org/D95159
2021-01-21 20:45:54 -08:00
Nico Weber 7799ef7121 Revert "Lex: Migrate HeaderSearch::LoadedModuleMaps to FileEntryRef"
This reverts commit a40db5502b.
and follow-up d636b881bb

Somewhat speculative, likely broke check-clang on Windows:
https://reviews.llvm.org/D92975#2453482
2020-12-14 22:05:08 -05:00
Duncan P. N. Exon Smith a40db5502b Lex: Migrate HeaderSearch::LoadedModuleMaps to FileEntryRef
Migrate `HeaderSearch::LoadedModuleMaps` and a number of APIs over to
`FileEntryRef`. This should have no functionality change. Note that two
`FileEntryRef`s hash the same if they point at the same `FileEntry`.

Differential Revision: https://reviews.llvm.org/D92975
2020-12-14 14:35:11 -08:00
Duncan P. N. Exon Smith 51d1d585e5 clang/Frontend: Use MemoryBufferRef in FrontendInputFile (and remove SourceManager::getBuffer)
In order to drop the final callers to `SourceManager::getBuffer`, change
`FrontendInputFile` to use `Optional<MemoryBufferRef>`. Also updated
the "unowned" version of `SourceManager::createFileID` to take a
`MemoryBufferRef` (it now calls `MemoryBuffer::getMemBuffer`, which
creates a `MemoryBuffer` that does not own the buffer data).

Differential Revision: https://reviews.llvm.org/D89427
2020-10-20 13:35:46 -04:00
Duncan P. N. Exon Smith b3eff6b7bb Lexer: Update the Lexer to use MemoryBufferRef, NFC
Update `Lexer` / `Lexer::Lexer` to use `MemoryBufferRef` instead of
`MemoryBuffer*`. Callers that were acquiring a `MemoryBuffer*` via
`SourceManager::getBuffer` were updated, such that if they checked
`Invalid` they use `getBufferOrNone` and otherwise `getBufferOrFake`.

Differential Revision: https://reviews.llvm.org/D89398
2020-10-19 19:10:21 -04:00
Duncan P. N. Exon Smith 63af242279 clang/Frontend: Mostly stop using SourceManager::getBuffer, NFC
Update clang/lib/Frontend to use a `MemoryBufferRef` from
`getBufferOrFake` instead of `MemoryBuffer*` from `getBuffer`, with the
exception of `FrontendInputFile`, which I'm leaving for later.

Differential Revision: https://reviews.llvm.org/D89409
2020-10-14 23:31:28 -04:00
Bruno Ricci 19701458d4
[clang][nearly-NFC] Remove some superfluous uses of NamedDecl::getNameAsString
`OS << ND->getDeclName();` is equivalent to `OS << ND->getNameAsString();`
without the extra temporary string.

This is not quite a NFC since two uses of `getNameAsString` in a
diagnostic are replaced, which results in the named entity being
quoted with additional "'"s (ie: 'var' instead of var).
2020-08-05 13:54:37 +01:00
Nathan James 8b0df1c1a9
[NFC] Refactor Registry loops to range for 2020-06-19 00:40:10 +01:00
Bruno Cardoso Lopes d892eec710 Reapply: Make header inclusion order from umbrella dirs deterministic
Sort the headers by name before adding the includes in
collectModuleHeaderIncludes. This makes the include order for building
umbrellas deterministic across different filesystems and also guarantees
that the ASTWriter always dump top headers in the same order.

There's currently no good way to test for this behavior.

This was first introduced in r289478 and reverted few times because of
ASANifed test failures on open source bots (both from LLVM and Swift).

Finally reproduced the problem in a Linux machine and use std::sort as a
fix, since we are not dealing with POD-like types.

rdar://problem/28116411
2020-04-21 15:45:54 -07:00
BoYao Zhang 2aa593be54 Fix a typo in an assert message; NFC. 2020-04-06 11:50:50 -04:00
Ben Langmuir c322d328aa Forward WrapperFrontendAction::shouldEraseOutputFiles()
Per the documentation, this class is supposed to forward every virtual
method, but we had missed on (shouldEraseOutputFiles). This fixes using
a wrapped frontend action over the PCH generator when using
-fallow-pch-with-compiler-errors. I do not think any upstream wrapper
actions can test this.

Differential Revision: https://reviews.llvm.org/D77180

rdar://61110294
2020-03-31 16:20:23 -07:00
Volodymyr Sapsai a6c8698924 clang/Modules: Finish renaming CompilerInstance::ModuleManager, NFC.
Follow-up to 20d51b2f14, rename the setter to
make it consistent with the getter. Also fixed a few comments along the
way, didn't try to find all references to a module manager.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D74939
2020-02-21 13:56:50 -08:00
Benjamin Kramer adcd026838 Make llvm::StringRef to std::string conversions explicit.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.
2020-01-28 23:25:25 +01:00
Duncan P. N. Exon Smith 20d51b2f14 clang/Modules: Rename CompilerInstance::ModuleManager, NFC
Fix the confusing naming of `CompilerInstance::ModuleManager`.  This is
actually an instance of `ASTReader`, which contains an instance of
`ModuleManager`.  I have to assume there was a point in the past where
they were just one class, but it's been pretty confusing for a while.  I
think it's time to fix it.

The new name is `TheASTReader`; the annoying `The` prefix is so that we
don't shadow the `ASTReader` class.  I tried out `ASTRdr` but that
seemed less clear, and this choice matches `ThePCHContainerOperations`
just a couple of declarations below.

Also rename `CompilerInstance::getModuleManager` and
`CompilerInstance::createModuleManager` to `*ASTReader`, making some
cases of `getModuleManager().getModuleManager()` a little more clear.

https://reviews.llvm.org/D70583
2019-11-22 18:24:11 -08:00
Reid Kleckner 979da9a4c3 Avoid including Builtins.h in Preprocessor.h
Builtins are rarely if ever accessed via the Preprocessor. They are
typically found on the ASTContext, so there should be no performance
penalty to using a pointer indirection to store the builtin context.
2019-11-15 16:45:16 -08:00
Jonas Devlieghere 2b3d49b610 [Clang] Migrate llvm::make_unique to std::make_unique
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

Differential revision: https://reviews.llvm.org/D66259

llvm-svn: 368942
2019-08-14 23:04:18 +00:00
Rainer Orth 09d890d728 Move LangStandard*, InputKind::Language to Basic
This patch is a prerequisite for using LangStandard from Driver in
https://reviews.llvm.org/D64793.

It moves LangStandard* and InputKind::Language to Basic.  It is mostly
mechanical, with only a few changes of note:

- enum Language has been changed into enum class Language : uint8_t to
  avoid a clash between OpenCL in enum Language and OpenCL in enum
  LangFeatures and not to increase the size of class InputKind.

- Now that getLangStandardForName, which is currently unused, also checks
  both canonical and alias names, I've introduced a helper getLangKind
  which factors out a code pattern already used 3 times.

The patch has been tested on x86_64-pc-solaris2.11, sparcv9-sun-solaris2.11,
and x86_64-pc-linux-gnu.

There's a companion patch for lldb which uses LangStandard.h
(https://reviews.llvm.org/D65717).

While polly includes isl which in turn uses InputKind::C, that part of the
code isn't even built inside the llvm tree.  I've posted a patch to allow
for both InputKind::C and Language::C upstream
(https://groups.google.com/forum/#!topic/isl-development/6oEvNWOSQFE).

Differential Revision: https://reviews.llvm.org/D65562

llvm-svn: 367864
2019-08-05 13:59:26 +00:00
Harlan Haskins 8d323d1506 [clang] Adopt new FileManager error-returning APIs
Update the callers of FileManager::getFile and FileManager::getDirectory to handle the new llvm::ErrorOr-returning methods.

Signed-off-by: Harlan Haskins <harlan@apple.com>
llvm-svn: 367616
2019-08-01 21:31:56 +00:00
JF Bastien 0e82895826 BitStream reader: propagate errors
The bitstream reader handles errors poorly. This has two effects:

 * Bugs in file handling (especially modules) manifest as an "unexpected end of
   file" crash
 * Users of clang as a library end up aborting because the code unconditionally
   calls `report_fatal_error`

The bitstream reader should be more resilient and return Expected / Error as
soon as an error is encountered, not way late like it does now. This patch
starts doing so and adopting the error handling where I think it makes sense.
There's plenty more to do: this patch propagates errors to be minimally useful,
and follow-ups will propagate them further and improve diagnostics.

https://bugs.llvm.org/show_bug.cgi?id=42311
<rdar://problem/33159405>

Differential Revision: https://reviews.llvm.org/D63518

llvm-svn: 364464
2019-06-26 19:50:12 +00:00
Duncan P. N. Exon Smith db8a742206 Basic: Return a reference from FileManager::getVirtualFileSystem, NFC
FileManager constructs a VFS in its constructor if it isn't passed one,
and there's no way to reset it.  Make that contract clear by returning a
reference from its accessor.

https://reviews.llvm.org/D59388

llvm-svn: 357038
2019-03-26 22:32:06 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Volodymyr Sapsai 4daffc176f [Frontend] Make WrapperFrontendAction call WrappedAction.PrepareToExecuteAction.
Fixes `-emit-header-module` when GenerateHeaderModuleAction is wrapped
by another frontend action.

rdar://problem/47302588

Reviewers: rsmith, arphaman

Reviewed By: arphaman

Subscribers: jkorous, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D56766

llvm-svn: 351402
2019-01-17 00:20:43 +00:00
Nico Weber b215d0731a Let new test from r350340 still pass even after r350451.
llvm-svn: 350453
2019-01-05 01:19:14 +00:00
Nico Weber 9f0c21c1e0 Move -add-plugin validation after -load was executed.
Moves the code added in r350340 around a bit, to hopefully make the existing
plugin tests pass when clang is built with examples enabled.

llvm-svn: 350451
2019-01-05 01:10:20 +00:00
David Blaikie 9941da4191 Sink BuryPointer from Clang into LLVM for reuse there
llvm-svn: 347141
2018-11-17 18:04:13 +00:00
Erik Pilkington fa98390b3c NFC: Remove the ObjC1/ObjC2 distinction from clang (and related projects)
We haven't supported compiling ObjC1 for a long time (and never will again), so
there isn't any reason to keep these separate. This patch replaces
LangOpts::ObjC1 and LangOpts::ObjC2 with LangOpts::ObjC.

Differential revision: https://reviews.llvm.org/D53547

llvm-svn: 345637
2018-10-30 20:31:30 +00:00
Sam McCall 5da4d75877 Remove top-level using declaration from header files, as these aliases leak.
Reviewers: ilya-biryukov

Subscribers: arphaman, cfe-commits

Differential Revision: https://reviews.llvm.org/D53135

llvm-svn: 344337
2018-10-12 12:21:29 +00:00
Jonas Devlieghere fc51490baf Lift VFS from clang to llvm (NFC)
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

llvm-svn: 344140
2018-10-10 13:27:25 +00:00
Richard Smith 8b464f299f [modules] Support use of -E on modules built from the command line.
llvm-svn: 342306
2018-09-15 01:21:18 +00:00
Richard Smith d6509cf21d [modules] Frontend support for building a header module from a list of
headaer files.

llvm-svn: 342304
2018-09-15 01:21:15 +00:00
Sam McCall 0ae00567ba [VFS] vfs::directory_iterator yields path and file type instead of full Status
Summary:
Most callers I can find are using only `getName()`. Type is used by the
recursive iterator.

Now we don't have to call stat() on every listed file (on most platforms).
Exceptions are e.g. Solaris where readdir() doesn't include type information.
On those platforms we'll still stat() - see D51918.

The result is significantly faster (stat() can be slow).
My motivation: this may allow us to improve clang IO on large TUs with long
include search paths. Caching readdir() results may allow us to skip many stat()
and open() operations on nonexistent files.

Reviewers: bkramer

Subscribers: fedor.sergeev, cfe-commits

Differential Revision: https://reviews.llvm.org/D51921

llvm-svn: 342232
2018-09-14 12:47:38 +00:00
Fangrui Song 6907ce2f8f Remove trailing space
sed -Ei 's/[[:space:]]+$//' include/**/*.{def,h,td} lib/**/*.{cpp,h}

llvm-svn: 338291
2018-07-30 19:24:48 +00:00
Bruno Cardoso Lopes 7315d2d721 [PCH+Modules] Load -fmodule-map-file content before including PCHs
Consider:
1) Generate PCH with -fmodules and -fmodule-map-file
2) Use PCH with -fmodules and the same -fmodule-map-file

If we don't load -fmodule-map-file content before including PCHs,
the modules that are dependencies in PCHs cannot get loaded,
since there's no matching module map file when reading back the AST.

rdar://problem/40852867

Differential Revision: https://reviews.llvm.org/D48685

llvm-svn: 337447
2018-07-19 12:32:06 +00:00
Vassil Vassilev da31c93794 Print the qualified name when dumping deserialized decls.
This is useful to understand and debug the lazy template specializations
used in the pch and modules.

Differential Revision: https://reviews.llvm.org/D41785

llvm-svn: 332817
2018-05-20 09:38:52 +00:00
Ivan Donchevskii 270ef5b85c [Frontend] Avoid running plugins during code completion parse
Second attempt. Proper line endings.

The parsing that is done for code completion is a special case that will
discard any generated diagnostics, so avoid running plugins for this
case in the first place to avoid performance penalties due to the
plugins.

A scenario for this is for example libclang with extra plugins like tidy.

Patch by Nikolai Kosjar

Differential Revision: https://reviews.llvm.org/D46050

llvm-svn: 332586
2018-05-17 09:21:07 +00:00
Ivan Donchevskii f70d28b1f4 Revert https://reviews.llvm.org/D46050 and https://reviews.llvm.org/D45815
Windows line endings.
Requires proper resubmission.

llvm-svn: 332585
2018-05-17 09:15:22 +00:00
Ivan Donchevskii 091069c91e [Frontend] Avoid running plugins during code completion parse
The parsing that is done for code completion is a special case that will
discard any generated diagnostics, so avoid running plugins for this
case in the first place to avoid performance penalties due to the
plugins.

A scenario for this is for example libclang with extra plugins like tidy.

Patch by Nikolai Kosjar

Differential Revision: https://reviews.llvm.org/D46050

llvm-svn: 332469
2018-05-16 13:50:05 +00:00
Adrian Prantl 9fc8faf9e6 Remove \brief commands from doxygen comments.
This is similar to the LLVM change https://reviews.llvm.org/D46290.

We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

for i in $(git grep -l '\@brief'); do perl -pi -e 's/\@brief //g' $i & done
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46320

llvm-svn: 331834
2018-05-09 01:00:01 +00:00
Nico Weber ade321e7dd Revert r329684 (and follow-ups 329693, 329714). See discussion on https://reviews.llvm.org/D43578.
llvm-svn: 329739
2018-04-10 18:53:28 +00:00
Andrew V. Tischenko c88deb100f -ftime-report switch support in Clang.
The current support of the feature produces only 2 lines in report:
 -Some general Code Generation Time;
 -Total time of Backend Consumer actions.
This patch extends Clang time report with new lines related to Preprocessor, Include Filea Search, Parsing, etc.
Differential Revision: https://reviews.llvm.org/D43578

llvm-svn: 329684
2018-04-10 10:34:13 +00:00
Bruno Cardoso Lopes c192d1942e Track shadow modules with a generation counter.
This is a follow up to r321855, closing the gap between our internal shadow
modules implementation and upstream. It has been tested for longer and
provides a better approach for tracking shadow modules. Mostly NFCI.

rdar://problem/23612102

llvm-svn: 321906
2018-01-05 22:13:56 +00:00
Raphael Isemann abc3d04e47 Use the VFS from the CompilerInvocation by default
Summary:
The CompilerInstance should create its default VFS from its CompilerInvocation. Right now the
user has to manually create the VFS before creating the FileManager even though
`-ivfsoverlay file.yaml` was passed via the CompilerInvocation (which is exactly how we worked
around this issue in `FrontendAction.cpp` so far).

This patch uses the invocation's VFS by default and also tests this behavior now from the
point of view of a program that uses the clang API.

Reviewers: benlangmuir, v.g.vassilev

Reviewed By: v.g.vassilev

Subscribers: mgorny, cfe-commits, v.g.vassilev

Differential Revision: https://reviews.llvm.org/D37416

llvm-svn: 313049
2017-09-12 16:54:53 +00:00