184 Commits

Author SHA1 Message Date
Chuanqi Xu
54cf24dc6e [NFC] Refactor ModuleDeclStateTest to make it not dependent on Frontend
Required in https://reviews.llvm.org/D137526. And it is indeed odd that
LexTest depends on ClangFrontend.
2023-02-15 11:30:18 +08:00
Jie Fu
35537aea12 [Modules][Test][NFC] Fix -Wsign-compare in clang/unittests/Lex/ModuleDeclStateTest.cpp
In file included from /data/jiefu/llvm-project/clang/unittests/Lex/ModuleDeclStateTest.cpp:22:
/data/jiefu/llvm-project/third-party/unittest/googletest/include/gtest/gtest.h:1526:11: error: comparison of integers of different signs: 'const unsigned long' and 'const int' [-Werror,-Wsign-compare]
  if (lhs == rhs) {
      ~~~ ^  ~~~
/data/jiefu/llvm-project/third-party/unittest/googletest/include/gtest/gtest.h:1553:12: note: in instantiation of function template specialization 'testing::internal::CmpHelperEQ<unsigned long, int>' requested here
    return CmpHelperEQ(lhs_expression, rhs_expression, lhs, rhs);
           ^
/data/jiefu/llvm-project/clang/unittests/Lex/ModuleDeclStateTest.cpp:124:3: note: in instantiation of function template specialization 'testing::internal::EqHelper::Compare<unsigned long, int, nullptr>' requested here
  EXPECT_EQ(Callback->importNamedModuleNum(), 0);
  ^
/data/jiefu/llvm-project/third-party/unittest/googletest/include/gtest/gtest.h:2027:54: note: expanded from macro 'EXPECT_EQ'
  EXPECT_PRED_FORMAT2(::testing::internal::EqHelper::Compare, val1, val2)
                                                     ^
1 error generated.
2023-02-10 10:51:21 +08:00
Chuanqi Xu
6470706bc0 [C++20] [Modules] [NFC] Add Preprocessor methods for named modules - for ClangScanDeps (1/4)
This patch prepares the necessary interfaces in the preprocessor part
for D137527 since we need to recognize if we're in a module unit, the
module kinds and the module declaration and the module we're importing
in the preprocessor.

Differential Revision: https://reviews.llvm.org/D137526
2023-02-10 10:11:36 +08:00
Jonas Hahnfeld
01eb01c7fd [clang][Lex] Add back PPCallbacks::FileNotFound
This callback was removed with commit 7a124f4859, but we use it
downstream in ROOT/Cling to implement handling of a special include
syntax. Add back a "safe" version of the callback that only takes
the file name and return a bool to silently skip the file.

Differential Revision: https://reviews.llvm.org/D142196
2023-01-24 09:52:27 +01:00
Kazu Hirata
6ad0788c33 [clang] Use std::optional instead of llvm::Optional (NFC)
This patch replaces (llvm::|)Optional< with std::optional<.  I'll post
a separate patch to remove #include "llvm/ADT/Optional.h".

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2023-01-14 12:31:01 -08:00
Kazu Hirata
a1580d7b59 [clang] Add #include <optional> (NFC)
This patch adds #include <optional> to those files containing
llvm::Optional<...> or Optional<...>.

I'll post a separate patch to actually replace llvm::Optional with
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2023-01-14 11:07:21 -08:00
serge-sans-paille
a3c248db87
Move from llvm::makeArrayRef to ArrayRef deduction guides - clang/ part
This is a follow-up to https://reviews.llvm.org/D140896, split into
several parts as it touches a lot of files.

Differential Revision: https://reviews.llvm.org/D141139
2023-01-09 12:15:24 +01:00
Benjamin Kramer
854c10f8d1 [Clang] Prepare for llvm::Optional becoming std::optional.
The needed tweaks are mostly trivial, the one nasty bit is Clang's usage
of OptionalStorage. To keep this working old Optional stays around as
clang::CustomizableOptional, with the default Storage removed.
Optional<File/DirectoryEntryRef> is replaced with a typedef.

I tested this with GCC 7.5, the oldest supported GCC I had around.

Differential Revision: https://reviews.llvm.org/D140332
2022-12-20 00:41:40 +01:00
Krzysztof Parzyszek
205c0589f9 Revert "[clang] Convert OptionalFileEntryRefDegradesToFileEntryPtr to std::optional"
This reverts commit 8f0df9f3bbc6d7f3d5cbfd955c5ee4404c53a75d.

The Optional*RefDegradesTo*EntryPtr types want to keep the same size as
the underlying type, which std::optional doesn't guarantee. For use with
llvm::Optional, they define their own storage class, and there is no way
to do that in std::optional.

On top of that, that commit broke builds with older GCCs, where
std::optional was not trivially copyable (static_assert in the clang
sources was failing).
2022-12-18 11:23:54 -08:00
Krzysztof Parzyszek
8f0df9f3bb [clang] Convert OptionalFileEntryRefDegradesToFileEntryPtr to std::optional 2022-12-17 15:24:14 -08:00
Fangrui Song
1e6adbadc7 [clang] llvm::Optional::value => operator*/operator->
std::optional::value() has undesired exception checking semantics and is
unavailable in older Xcode (see _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS). The
call sites block std::optional migration.

This makes `ninja check-clang` work in the absence of llvm::Optional::value.
2022-12-17 08:10:45 +00:00
Kazu Hirata
a41fbb1fc2 [clang/unittests] Use std::nullopt instead of None (NFC)
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-12-03 12:14:19 -08:00
Sam McCall
2c1fa73459 Reland "[Lex] Fix suggested spelling of /usr/bin/../include/foo"
This reverts commit 1dc0a1e5d220b83c1074204bd3afd54f3bac4270.

Failures were caused by unintentional conversion to native slashes by
remove_dots, so undo that: we always suggest posix slashes for includes.

This could potentially be a change in behavior on windows if people were
spelling headers with backslashes and headermaps contained backslashes,
but that's all underspecified and I don't think anyone uses headermaps
on windows.

Differential Revision: https://reviews.llvm.org/D138709
2022-11-28 10:09:13 +01:00
Sam McCall
1dc0a1e5d2 Revert "[Lex] Fix suggested spelling of /usr/bin/../include/foo"
This reverts commit 8bed59c7e7da2fea41a9167e15c15a8f58a5ede7.

Breaks bots e.g. https://lab.llvm.org/buildbot/#/builders/216/builds/13282
2022-11-25 14:01:39 +01:00
Sam McCall
8bed59c7e7 [Lex] Fix suggested spelling of /usr/bin/../include/foo
Since D60873 we remove dotdots from the search path entries, but not the
filenames we're matching against, so do the latter too.

Since this also removes (single) dots, drop the logic to skip over them.
(Some of this was already dead, some is newly dead).

See D138676 for motivation.

Differential Revision: https://reviews.llvm.org/D138677
2022-11-25 11:01:22 +01:00
Nathan James
108e41d962
[clang][NFC] Use c++17 style variable type traits
This was done as a test for D137302 and it makes sense to push these changes

Reviewed By: shafik

Differential Revision: https://reviews.llvm.org/D137491
2022-11-07 18:25:48 +00:00
Kadir Cetinkaya
36f77e20d9
Revert "Revert "[clang][Lex] Fix a crash on malformed string literals""
This reverts commit feea7ef23cb1bef92d363cc613052f8f3a878fc2.
Drops the test case, see https://reviews.llvm.org/D135161#3839510
2022-10-06 11:41:18 +02:00
Kadir Cetinkaya
feea7ef23c
Revert "[clang][Lex] Fix a crash on malformed string literals"
This reverts commit 36a200208facf58d454c9b7253c956c2f2a8b946.
2022-10-05 10:37:32 +02:00
Kadir Cetinkaya
36a200208f
[clang][Lex] Fix a crash on malformed string literals
Differential Revision: https://reviews.llvm.org/D135161
2022-10-05 09:55:50 +02:00
Argyrios Kyrtzidis
b340c5ae42 [Lex/DependencyDirectivesScanner] Handle the case where the source line starts with a tok::hashhash
Differential Revision: https://reviews.llvm.org/D133674
2022-09-13 15:48:50 -07:00
Jonas Hahnfeld
f0403c853b Fix build of Lex unit test with CLANG_DYLIB
If CLANG_LINK_CLANG_DYLIB, clang_target_link_libraries ignores all
indivial libraries and only links clang-cpp. As LLVMTestingSupport
is separate, pass it via target_link_libraries directly.
2022-09-12 13:49:57 +02:00
Argyrios Kyrtzidis
aa484c90cf [Lex/DependencyDirectivesScanner] Keep track of the presence of tokens between the last scanned directive and EOF
Directive `dependency_directives_scan::tokens_present_before_eof` is introduced to indicate there were tokens present before
the last scanned dependency directive and EOF.
This is useful to ensure we correctly identify the macro guards when lexing using the dependency directives.

Differential Revision: https://reviews.llvm.org/D133357
2022-09-07 10:31:29 -07:00
Kazu Hirata
cb2c8f694d [clang] Use value instead of getValue (NFC) 2022-07-13 23:39:33 -07:00
Kazu Hirata
53daa177f8 [clang, clang-tools-extra] Use has_value instead of hasValue (NFC) 2022-07-12 22:47:41 -07:00
Kazu Hirata
3b7c3a654c Revert "Don't use Optional::hasValue (NFC)"
This reverts commit aa8feeefd3ac6c78ee8f67bf033976fc7d68bc6d.
2022-06-25 11:56:50 -07:00
Kazu Hirata
aa8feeefd3 Don't use Optional::hasValue (NFC) 2022-06-25 11:55:57 -07:00
Kazu Hirata
b8df4093e4 [clang, clang-tools-extra] Don't use Optional::{hasValue,getValue} (NFC) 2022-06-25 11:55:33 -07:00
Argyrios Kyrtzidis
b4c83a13f6 [Tooling/DependencyScanning & Preprocessor] Refactor dependency scanning to produce pre-lexed preprocessor directive tokens, instead of minimized sources
This is a commit with the following changes:

* Remove `ExcludedPreprocessorDirectiveSkipMapping` and related functionality

Removes `ExcludedPreprocessorDirectiveSkipMapping`; its intended benefit for fast skipping of excluded directived blocks
will be superseded by a follow-up patch in the series that will use dependency scanning lexing for the same purpose.

* Refactor dependency scanning to produce pre-lexed preprocessor directive tokens, instead of minimized sources

Replaces the "source minimization" mechanism with a mechanism that produces lexed dependency directives tokens.

* Make the special lexing for dependency scanning a first-class feature of the `Preprocessor` and `Lexer`

This is bringing the following benefits:

    * Full access to the preprocessor state during dependency scanning. E.g. a component can see what includes were taken and where they were located in the actual sources.
    * Improved performance for dependency scanning. Measurements with a release+thin-LTO build shows ~ -11% reduction in wall time.
    * Opportunity to use dependency scanning lexing to speed-up skipping of excluded conditional blocks during normal preprocessing (as follow-up, not part of this patch).

For normal preprocessing measurements show differences are below the noise level.

Since, after this change, we don't minimize sources and pass them in place of the real sources, `DependencyScanningFilesystem` is not technically necessary, but it has valuable performance benefits for caching file `stat`s along with the results of scanning the sources. So the setup of using the `DependencyScanningFilesystem` during a dependency scan remains.

Differential Revision: https://reviews.llvm.org/D125486
Differential Revision: https://reviews.llvm.org/D125487
Differential Revision: https://reviews.llvm.org/D125488
2022-05-26 12:50:06 -07:00
Argyrios Kyrtzidis
b58a420ff4 [Tooling/DependencyScanning] Rename refactorings towards transitioning dependency scanning to use pre-lexed preprocessor directive tokens
This is first of a series of patches for making the special lexing for dependency scanning a first-class feature of the `Preprocessor` and `Lexer`.
This patch only includes NFC renaming changes to make reviewing of the functionality changing parts easier.

Differential Revision: https://reviews.llvm.org/D125484
2022-05-26 12:49:51 -07:00
Cyndy Ishida
b6c67c3c67 [clang] Track how headers get included generally during lookup time
tapi & clang-extractapi both attempt to construct then check against
how a header was included to determine api information when working
against multiple search paths, headermap, and vfsoverlay mechanisms.
Validating this against what the preprocessor sees during lookup time
makes this check more reliable.

Reviewed By: zixuw, jansvoboda11

Differential Revision: https://reviews.llvm.org/D124638
2022-05-04 09:52:31 -07:00
Jan Svoboda
d79ad2f1db [clang][lex] NFCI: Use FileEntryRef in PPCallbacks::InclusionDirective()
This patch changes type of the `File` parameter in `PPCallbacks::InclusionDirective()` from `const FileEntry *` to `Optional<FileEntryRef>`.

With the API change in place, this patch then removes some uses of the deprecated `FileEntry::getName()` (e.g. in `DependencyGraph.cpp` and `ModuleDependencyCollector.cpp`).

Reviewed By: dexonsmith, bnbarham

Differential Revision: https://reviews.llvm.org/D123574
2022-04-14 10:46:12 +02:00
Jan Svoboda
d8298f04a9 [clang][lex][minimizer] Avoid treating path separators as comments
The minimizer strips out single-line comments (introduced by `//`). This sequence of characters can also appear in `#include` or `#import` directives where they play the role of path separators. We already avoid stripping this character sequence for `#include` but not for `#import` (which has the same semantics). This patch makes it so `#import <A//A.h>` is not affected by minimization. Previously, we would incorrectly reduce it into `#import <A`.

Reviewed By: arphaman

Differential Revision: https://reviews.llvm.org/D119226
2022-02-15 09:49:19 +01:00
Jan Svoboda
fd2dff17c5 [clang][lex][minimizer] Ensure whitespace between squashed lines
The minimizer tries to squash multi-line macro definitions into single line. For that to work, contents of each line need to be separated by a space. Since we always strip leading whitespace on lines of a macro definition, the code currently tries to preserve exactly one space that appeared before the backslash.

This means the following code:

```
#define FOO(BAR) \
  #BAR           \
  baz
```

gets minimized into:

```
#define FOO(BAR) #BAR baz
```

However, if there are no spaces before the backslash on line 2:

```
#define FOO(BAR) \
  #BAR\
  baz
```

no space can be preserved, leading to (most likely) malformed macro definition:

```
#define FOO(BAR) #BARbaz
```

This patch makes sure we always put exactly one space at the end of line ending with a backslash.

Reviewed By: arphaman

Differential Revision: https://reviews.llvm.org/D119231
2022-02-15 09:49:03 +01:00
Alex Lorenz
00cd6c0420 [Preprocessor] Reduce the memory overhead of #define directives (Recommit)
Recently we observed high memory pressure caused by clang during some parallel builds.
We discovered that we have several projects that have a large number of #define directives
in their TUs (on the order of millions), which caused huge memory consumption in clang due
to a lot of allocations for MacroInfo. We would like to reduce the memory overhead of
clang for a single #define to reduce the memory overhead for these files, to allow us to
reduce the memory pressure on the system during highly parallel builds. This change achieves
that by removing the SmallVector in MacroInfo and instead storing the tokens in an array
allocated using the bump pointer allocator, after all tokens are lexed.

The added unit test with 1000000 #define directives illustrates the problem. Prior to this
change, on arm64 macOS, clang's PP bump pointer allocator allocated 272007616 bytes, and
used roughly 272 bytes per #define. After this change, clang's PP bump pointer allocator
allocates 120002016 bytes, and uses only roughly 120 bytes per #define.

For an example test file that we have internally with 7.8 million #define directives, this
change produces the following improvement on arm64 macOS: Persistent allocation footprint for
this test case file as it's being compiled to LLVM IR went down 22% from 5.28 GB to 4.07 GB
and the total allocations went down 14% from 8.26 GB to 7.05 GB. Furthermore, this change
reduced the total number of allocations made by the system for this clang invocation from
1454853 to 133663, an order of magnitude improvement.

The recommit fixes the LLDB build failure.

Differential Revision: https://reviews.llvm.org/D117348
2022-02-14 09:27:44 -08:00
Alex Lorenz
3f05192c4c Revert "[Preprocessor] Reduce the memory overhead of #define directives"
This reverts commit 0d9b91524ea4db3760791bba15773c386a26d8ec.

This change broke LLDB's build. I will need to recommit after fixing LLDB.
2022-02-11 15:53:16 -08:00
Alex Lorenz
0d9b91524e [Preprocessor] Reduce the memory overhead of #define directives
Recently we observed high memory pressure caused by clang during some parallel builds.
We discovered that we have several projects that have a large number of #define directives
in their TUs (on the order of millions), which caused huge memory consumption in clang due
to a lot of allocations for MacroInfo. We would like to reduce the memory overhead of
clang for a single #define to reduce the memory overhead for these files, to allow us to
reduce the memory pressure on the system during highly parallel builds. This change achieves
that by removing the SmallVector in MacroInfo and instead storing the tokens in an array
allocated using the bump pointer allocator, after all tokens are lexed.

The added unit test with 1000000 #define directives illustrates the problem. Prior to this
change, on arm64 macOS, clang's PP bump pointer allocator allocated 272007616 bytes, and
used roughly 272 bytes per #define. After this change, clang's PP bump pointer allocator
allocates 120002016 bytes, and uses only roughly 120 bytes per #define.

For an example test file that we have internally with 7.8 million #define directives, this
change produces the following improvement on arm64 macOS: Persistent allocation footprint for
this test case file as it's being compiled to LLVM IR went down 22% from 5.28 GB to 4.07 GB
and the total allocations went down 14% from 8.26 GB to 7.05 GB. Furthermore, this change
reduced the total number of allocations made by the system for this clang invocation from
1454853 to 133663, an order of magnitude improvement.

Differential Revision: https://reviews.llvm.org/D117348
2022-02-11 15:01:10 -08:00
Kadir Cetinkaya
f59787084e
[clang][Lexer] Fix tests after ff77071a4d67 2022-02-07 14:06:32 +01:00
David Goldman
9385ece95a [HeaderSearch] Track framework name in LookupFile
Previously, the Framework name was only set if the file
came from a header mapped framework; now we'll always
set the framework name if the file is in a framework.

Differential Revision: https://reviews.llvm.org/D117830
2022-02-04 13:32:39 -05:00
Kadir Cetinkaya
ff77071a4d
[clang][Lexer] Make raw and normal lexer behave the same for line comments
Normally there are heruistics in lexer to treat `//*` specially in
language modes that don't have line comments (to emit `/`). Unfortunately this
only applied to the first occurence of a line comment inside the file, as the
subsequent line comments were treated as if language had support for them.

This unfortunately only holds in normal lexing mode, as in raw mode all
occurences of line comments received this treatment, which created discrepancies
when comparing expanded and spelled tokens.

The proper fix would be to just make sure we treat all the line comments with a
subsequent `*` the same way, but it would imply breaking some code that's
accepted by clang today. So instead we introduce the same bug into raw lexing
mode.

Fixes https://github.com/clangd/clangd/issues/1003.

Differential Revision: https://reviews.llvm.org/D118471
2022-01-31 16:15:16 +01:00
Jan Svoboda
105c913156 [clang][lex] NFC: Simplify calls to LookupFile
The `{HeaderSearch,Preprocessor}::LookupFile()` functions take an out-parameter `const DirectoryLookup *&`. Most callers end up creating a `const DirectoryLookup *` variable that's otherwise unused.

This patch changes the out-parameter from reference to a pointer, making it possible to simply pass `nullptr` to the function without the ceremony.

Reviewed By: ahoppen

Differential Revision: https://reviews.llvm.org/D117312
2022-01-18 16:02:18 +01:00
Jan Svoboda
ccd7e7830f Revert "[clang][lex] Keep references to DirectoryLookup objects up-to-date"
This reverts commit 8503c688. This patch causes some issues with `#include_next`: https://github.com/llvm/llvm-project/issues/53161
2022-01-13 16:29:44 +01:00
Jan Svoboda
f77d115cc1 [clang] Move ApplyHeaderSearchOptions from Frontend to Lex
In D116750, the `clangFrontend` library was added as a dependency of `LexTests` in order to make `clang::ApplyHeaderSearchOptions()` available. This increased the number of TUs the test depends on.

This patch moves the function into `clangLex` and removes dependency of `LexTests` on `clangFrontend`.

Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D117024
2022-01-11 17:57:40 +01:00
Jan Svoboda
8503c688d5 [clang][lex] Keep references to DirectoryLookup objects up-to-date
The elements of `SearchPath::SearchDirs` are being referenced to by their indices. This proved to be error-prone: `HeaderSearch::SearchDirToHSEntry` was accidentally not being updated in `HeaderSearch::AddSearchPath()`. This patch fixes that by referencing `SearchPath::SearchDirs` elements by their address instead, which is stable thanks to the bump-ptr-allocation strategy.

Reviewed By: ahoppen

Differential Revision: https://reviews.llvm.org/D116750
2022-01-11 15:24:46 +01:00
David Goldman
0cf7e61a42 [clang][HeaderSearch] Support framework includes in suggestPath...
Clang will now search through the framework includes to identify
the framework include path to a file, and then suggest a framework
style include spelling for the file.

Differential Revision: https://reviews.llvm.org/D115183
2022-01-10 12:25:53 -05:00
Sylvain Audi
a82a844961 [clang][deps] Keep #pragma push_macro, pop_macro and include_alias when minimizing source code.
The #pragma directives push_macro/pop_macro and include_alias may influence the #include / import directives encountered by dependency scanning tools like clang-scan-deps.

This patch ensures that those directives are not removed during source code minimization.

Differential Revision: https://reviews.llvm.org/D112088
2021-11-01 16:04:52 -04:00
Duncan P. N. Exon Smith
9902362701 Support: Use sys::path::is_style_{posix,windows}() in a few places
Use the new sys::path::is_style_posix() and is_style_windows() in a few
places that need to detect the system's native path style.

In llvm/lib/Support/Path.cpp, this patch removes most uses of the
private `real_style()`, where is_style_posix() and is_style_windows()
are just a little tidier.

Elsewhere, this removes `_WIN32` macro checks. Added a FIXME to a
FileManagerTest that seemed fishy, but maintained the existing
behaviour.

Differential Revision: https://reviews.llvm.org/D112289
2021-10-29 12:09:41 -07:00
Cyndy Ishida
395e1fe305 [clang] Capture Framework when HeaderSearch is resolved via headermap
When building frameworks, headermaps responsible for mapping angle-included headers to their source file location are passed via
`-I` and not `-index-header-map`. Also, `-index-header-map` is only used for indexing purposes and not during most builds.
This patch holds on to the framework's name in HeaderFileInfo as this is retrieveable for cases outside of IndexHeaderMaps and
still represents the framework that is being built.

resolves: rdar://84046893

Reviewed By: jansvoboda11

Differential Revision: https://reviews.llvm.org/D111468
2021-10-15 09:12:31 -07:00
Yitzhak Mandelbaum
93dc73b1e0 [Lexer] Fix bug in makeFileCharRange called on split tokens.
When the end loc of the specified range is a split token, `makeFileCharRange`
does not process it correctly.  This patch adds proper support for split tokens.

Differential Revision: https://reviews.llvm.org/D105365
2021-07-14 14:36:31 +00:00
Vassil Vassilev
11b47c103a Reland "[clang-repl] Implement partial translation units and error recovery."
Original commit message:

[clang-repl] Implement partial translation units and error recovery.

https://reviews.llvm.org/D96033 contained a discussion regarding efficient
modeling of error recovery. @rjmccall has outlined the key ideas:

Conceptually, we can split the translation unit into a sequence of partial
translation units (PTUs). Every declaration will be associated with a unique PTU
that owns it.

The first key insight here is that the owning PTU isn't always the "active"
(most recent) PTU, and it isn't always the PTU that the declaration
"comes from". A new declaration (that isn't a redeclaration or specialization of
anything) does belong to the active PTU. A template specialization, however,
belongs to the most recent PTU of all the declarations in its signature - mostly
that means that it can be pulled into a more recent PTU by its template
arguments.

The second key insight is that processing a PTU might extend an earlier PTU.
Rolling back the later PTU shouldn't throw that extension away. For example, if
the second PTU defines a template, and the third PTU requires that template to
be instantiated at float, that template specialization is still part of the
second PTU. Similarly, if the fifth PTU uses an inline function belonging to the
fourth, that definition still belongs to the fourth. When we go to emit code in
a new PTU, we map each declaration we have to emit back to its owning PTU and
emit it in a new module for just the extensions to that PTU. We keep track of
all the modules we've emitted for a PTU so that we can unload them all if we
decide to roll it back.

Most declarations/definitions will only refer to entities from the same or
earlier PTUs. However, it is possible (primarily by defining a
previously-declared entity, but also through templates or ADL) for an entity
that belongs to one PTU to refer to something from a later PTU. We will have to
keep track of this and prevent unwinding to later PTU when we recognize it.
Fortunately, this should be very rare; and crucially, we don't have to do the
bookkeeping for this if we've only got one PTU, e.g. in normal compilation.
Otherwise, PTUs after the first just need to record enough metadata to be able
to revert any changes they've made to declarations belonging to earlier PTUs,
e.g. to redeclaration chains or template specialization lists.

It should even eventually be possible for PTUs to provide their own slab
allocators which can be thrown away as part of rolling back the PTU. We can
maintain a notion of the active allocator and allocate things like Stmt/Expr
nodes in it, temporarily changing it to the appropriate PTU whenever we go to do
something like instantiate a function template. More care will be required when
allocating declarations and types, though.

We would want the PTU to be efficiently recoverable from a Decl; I'm not sure
how best to do that. An easy option that would cover most declarations would be
to make multiple TranslationUnitDecls and parent the declarations appropriately,
but I don't think that's good enough for things like member function templates,
since an instantiation of that would still be parented by its original class.
Maybe we can work this into the DC chain somehow, like how lexical DCs are.

We add a different kind of translation unit `TU_Incremental` which is a
complete translation unit that we might nonetheless incrementally extend later.
Because it is complete (and we might want to generate code for it), we do
perform template instantiation, but because it might be extended later, we don't
warn if it declares or uses undefined internal-linkage symbols.

This patch teaches clang-repl how to recover from errors by disconnecting the
most recent PTU and update the primary PTU lookup tables. For instance:

```./clang-repl
clang-repl> int i = 12; error;
In file included from <<< inputs >>>:1:
input_line_0:1:13: error: C++ requires a type specifier for all declarations
int i = 12; error;
            ^
error: Parsing failed.
clang-repl> int i = 13; extern "C" int printf(const char*,...);
clang-repl> auto r1 = printf("i=%d\n", i);
i=13
clang-repl> quit
```

Differential revision: https://reviews.llvm.org/D104918
2021-07-12 15:21:22 +00:00
Vassil Vassilev
5922f234c8 Revert "[clang-repl] Implement partial translation units and error recovery."
This reverts commit 6775fc6ffa3ca1c36b20c25fa4e7f48f81213cf2.

It also reverts "[lldb] Fix compilation by adjusting to the new ASTContext signature."

This reverts commit 03a3f86071c10a1f6cbbf7375aa6fe9d94168972.

We see some failures on the lldb infrastructure, these changes might play a role
in it. Let's revert it now and see if the bots will become green.

Ref: https://reviews.llvm.org/D104918
2021-07-11 14:40:10 +00:00