This is take two of #70976. This iteration of the patch makes sure that
custom
diagnostics without any warning group don't get promoted by `-Werror` or
`-Wfatal-errors`.
This implements parts of the extension proposed in
https://discourse.llvm.org/t/exposing-the-diagnostic-engine-to-c/73092/7.
Specifically, this makes it possible to specify a diagnostic group in an
optional third argument.
This reverts commit c3ba6f378ef80d750e2278560c6f95a300114412.
We are seeing performance regressions of up to 40% on some compilations
with this patch, we will investigate and reland after fixing performance
issues.
…ecord level.
This fixes the incorrect diagnostic emitted when compiling the following
snippet
```
// string_view.h
template<class _CharT>
class basic_string_view;
typedef basic_string_view<char> string_view;
template<class _CharT>
class
__attribute__((__preferred_name__(string_view)))
basic_string_view {
public:
basic_string_view()
{
}
};
inline basic_string_view<char> foo()
{
return basic_string_view<char>();
}
// A.cppm
module;
#include "string_view.h"
export module A;
// Use.cppm
module;
#include "string_view.h"
export module Use;
import A;
```
The diagnostic is
```
string_view.h:11:5: error: 'basic_string_view<char>::basic_string_view' from module 'A.<global>' is not present in definition of 'string_view' provided earlier
```
The underlying issue is that deserialization of the `preferred_name`
attribute triggers deserialization of `basic_string_view<char>`, which
triggers the deserialization of the `preferred_name` attribute again
(since it's attached to the `basic_string_view` template).
The deserialization logic is implemented in a way that prevents it from
going on a loop in a literal sense (it detects early on that it has
already seen the `string_view` typedef when trying to start its
deserialization for the second time), but leaves the typedef
deserialization in an unfinished state. Subsequently, the `string_view`
typedef from the deserialized module cannot be merged with the same
typedef from `string_view.h`, resulting in the above diagnostic.
This PR resolves the problem by delaying the deserialization of the
`preferred_name` attribute until the deserialization of the
`basic_string_view` template is completed. As a result of deferring, the
deserialization of the `preferred_name` attribute doesn't need to go on
a loop since the type of the `string_view` typedef is already known when
it's deserialized.
Close https://github.com/llvm/llvm-project/issues/90154
This patch is also an optimization to the lookup process to utilize the
information provided by `export` keyword.
Previously, in the lookup process, the `export` keyword only takes part
in the check part, it doesn't get involved in the lookup process. That
said, previously, in a name lookup for 'name', we would load all of
declarations with the name 'name' and check if these declarations are
valid or not. It works well. But it is inefficient since it may load
declarations that may not be wanted.
Note that this patch actually did a trick in the lookup process instead
of bring module information to DeclarationName or considering module
information when deciding if two declarations are the same. So it may
not be a surprise to me if there are missing cases. But it is not a
regression. It should be already the case. Issue reports are welcomed.
In this patch, I tried to split the big lookup table into a lookup table
as before and a module local lookup table, which takes a combination of
the ID of the DeclContext and hash value of the primary module name as
the key. And refactored `DeclContext::lookup()` method to take the
module information. So that a lookup in a DeclContext won't load
declarations that are local to **other** modules.
And also I think it is already beneficial to split the big lookup table
since it may reduce the conflicts during lookups in the hash table.
BTW, this patch introduced a **regression** for a reachability rule in
C++20 but it was false-negative. See
'clang/test/CXX/module/module.interface/p7.cpp' for details.
This patch is not expected to introduce any other
regressions for non-c++20-modules users since the module local lookup
table should be empty for them.
Close https://github.com/llvm/llvm-project/issues/90154
This patch is also an optimization to the lookup process to utilize the
information provided by `export` keyword.
Previously, in the lookup process, the `export` keyword only takes part
in the check part, it doesn't get involved in the lookup process. That
said, previously, in a name lookup for 'name', we would load all of
declarations with the name 'name' and check if these declarations are
valid or not. It works well. But it is inefficient since it may load
declarations that may not be wanted.
Note that this patch actually did a trick in the lookup process instead
of bring module information to DeclarationName or considering module
information when deciding if two declarations are the same. So it may
not be a surprise to me if there are missing cases. But it is not a
regression. It should be already the case. Issue reports are welcomed.
In this patch, I tried to split the big lookup table into a lookup table
as before and a module local lookup table, which takes a combination of
the ID of the DeclContext and hash value of the primary module name as
the key. And refactored `DeclContext::lookup()` method to take the
module information. So that a lookup in a DeclContext won't load
declarations that are local to **other** modules.
And also I think it is already beneficial to split the big lookup table
since it may reduce the conflicts during lookups in the hash table.
BTW, this patch introduced a **regression** for a reachability rule in
C++20 but it was false-negative. See
'clang/test/CXX/module/module.interface/p7.cpp' for details.
This patch is not expected to introduce any other
regressions for non-c++20-modules users since the module local lookup
table should be empty for them.
---
On the API side, this patch unfortunately add a maybe-confusing argument
`Module *NamedModule` to
`ExternalASTSource::FindExternalVisibleDeclsByName()`. People may think
we can get the information from the first argument `const DeclContext
*DC`. But sadly there are declarations (e.g., namespace) can appear in
multiple different modules as a single declaration. So we have to add
additional information to indicate this.
The 'align' modifier is now accepted in the 'allocate' clause. Added LIT
tests covering codegen, PCH, template handling, and serialization for
'align' modifier.
Added support for align-modifier to release notes.
Testing
- New allocate modifier LIT tests.
- OpenMP LIT tests.
- check-all
These two clauses just take a 'var-list' and specify where the variables
should be copied from/to. This patch implements the AST nodes for them
and ensures they properly take a var-list.
The 'self' clause is an unfortunately difficult one, as it has a
significantly different meaning between 'update' and the other
constructs. This patch introduces a way for the 'self' clause to work
as both. I considered making this two separate AST nodes (one for
'self' on 'update' and one for the others), however this makes the
automated macros/etc for supporting a clause break.
Instead, 'self' has the ability to act as either a condition or as a
var-list clause. As this is the only one of its kind, it is implemented
all within it. If in the future we have more that work like this, we
should consider rewriting a lot of the macros that we use to make
clauses work, and make them separate ast nodes.
A fairly simple one, only valid on the 'set' construct, this clause
takes an int expression. Most of the work was already done as a part of
parsing, so this patch ends up being a lot of infrastructure.
An instantiated templated function definition may not have a body due to
parsing errors inside the templated function. When serializing, an
assert is triggered inside `ASTRecordWriter::AddFunctionDefinition`.
The instantiation may happen on an intermediate module.
The test case was reduced from `mp-units`.
This is a very simple sema implementation, and just required AST node
plus the existing diagnostics. This patch adds tests and adds the AST
node required, plus enables it for 'init' and 'shutdown' (only!)
This is a clause that is only valid on 'host_data' constructs, and
identifies variables which it should use the current device address.
From a Sema perspective, the only thing novel here is mild changes to
how ActOnVar works for this clause, else this is very much like the rest
of the 'var-list' clauses.
'delete' is another clause that has very little compile-time
implication, but needs a full AST that takes a var list. This patch
ipmlements it fully, plus adds sufficient test coverage.
This is another new clause specific to 'exit data' that takes a pointer
argument. This patch implements this the same way we do a few other
clauses (like attach) that have the same restrictions.
The 'if_present' clause controls the replacement of addresses in the
var-list in current device memory. This clause can only go on
'host_device'. From a Sema perspective, there isn't anything to do
beyond add this to AST and pass it on.
This is a very simple clause as far as sema is concerned. It is only
valid on 'exit data', and doesn't have any rules involving it, so it is
simply applied and passed onto the MLIR.
Reland https://github.com/llvm/llvm-project/pull/83237
---
(Original comments)
Currently all the specializations of a template (including
instantiation, specialization and partial specializations) will be
loaded at once if we want to instantiate another instance for the
template, or find instantiation for the template, or just want to
complete the redecl chain.
This means basically we need to load every specializations for the
template once the template declaration got loaded. This is bad since
when we load a specialization, we need to load all of its template
arguments. Then we have to deserialize a lot of unnecessary
declarations.
For example,
```
// M.cppm
export module M;
export template <class T>
class A {};
export class ShouldNotBeLoaded {};
export class Temp {
A<ShouldNotBeLoaded> AS;
};
// use.cpp
import M;
A<int> a;
```
We have a specialization ` A<ShouldNotBeLoaded>` in `M.cppm` and we
instantiate the template `A` in `use.cpp`. Then we will deserialize
`ShouldNotBeLoaded` surprisingly when compiling `use.cpp`. And this
patch tries to avoid that.
Given that the templates are heavily used in C++, this is a pain point
for the performance.
This patch adds MultiOnDiskHashTable for specializations in the
ASTReader. Then we will only deserialize the specializations with the
same template arguments. We made that by using ODRHash for the template
arguments as the key of the hash table.
To review this patch, I think `ASTReaderDecl::AddLazySpecializations`
may be a good entry point.
Note that PointerUnion::{is,get} have been soft deprecated in
PointerUnion.h:
// FIXME: Replace the uses of is(), get() and dyn_cast() with
// isa<T>, cast<T> and the llvm::dyn_cast<T>
I'm not touching PointerUnion::dyn_cast for now because it's a bit
complicated; we could blindly migrate it to dyn_cast_if_present, but
we should probably use dyn_cast when the operand is known to be
non-null.
Currently all the specializations of a template (including
instantiation, specialization and partial specializations) will be
loaded at once if we want to instantiate another instance for the
template, or find instantiation for the template, or just want to
complete the redecl chain.
This means basically we need to load every specializations for the
template once the template declaration got loaded. This is bad since
when we load a specialization, we need to load all of its template
arguments. Then we have to deserialize a lot of unnecessary
declarations.
For example,
```
// M.cppm
export module M;
export template <class T>
class A {};
export class ShouldNotBeLoaded {};
export class Temp {
A<ShouldNotBeLoaded> AS;
};
// use.cpp
import M;
A<int> a;
```
We should a specialization ` A<ShouldNotBeLoaded>` in `M.cppm` and we
instantiate the template `A` in `use.cpp`. Then we will deserialize
`ShouldNotBeLoaded` surprisingly when compiling `use.cpp`. And this
patch tries to avoid that.
Given that the templates are heavily used in C++, this is a pain point
for the performance.
This patch adds MultiOnDiskHashTable for specializations in the
ASTReader. Then we will only deserialize the specializations with the
same template arguments. We made that by using ODRHash for the template
arguments as the key of the hash table.
To review this patch, I think `ASTReaderDecl::AddLazySpecializations`
may be a good entry point.
The patch was reviewed in
https://github.com/llvm/llvm-project/pull/83237 but that PR is a stacked
PR. But I feel the intention of the stacked PRs get lost during the
review process. So I feel it is better to merge the commits into a
single commit instead of merging them in the PR page. It is better for
us to cherry-pick and revert.
This is a follow up to #112015 and it reduces the unnecessary
duplication of source locations further.
We do not need to allocate source location space in the serialized PCMs
for module maps used only to find textual headers. Those module maps are
never referenced from anywhere in the serialized ASTs and are re-read in
other compilations.
This change should not affect correctness of Clang compilations or
clang-scan-deps in any way.
We do need the InputFile entry in the serialized AST because
clang-scan-deps relies on it. The previous patch introduced a mechanism
to do exactly that.
We have found that to finally remove any duplication of module maps we
use internally in our build system.
This PR changes a part of the PCM format to store string-like things in
the blob attached to a record instead of VBR6-encoding them into the
record itself. Applied to the `IMPORTS` section (which is very hot),
this speeds up dependency scanning by 2.8%.
This PR builds on top of
https://github.com/llvm/llvm-project/pull/115235 and makes it possible
to call `ASTWriter::WriteAST()` with `Preprocessor` only instead of full
`Sema` object. So far, there are no clients that leverage the new
capability - that will come in a follow-up commit.
Currently, any FileID that references a module map file that was
required for a compilation is considered as affecting. This misses an
important opportunity to reduce the source location space taken by the
resulting PCM.
In particular, consider the situation where the same module map file is
passed multiple times in the dependency chain:
```shell
$ clang -fmodule-map-file=foo.modulemap ... -o mod1.pcm
$ clang -fmodule-map-file=foo.modulemap -fmodule-file=mod1.pcm ... -o mod2.pcm
...
$ clang -fmodule-map-file=foo.modulemap -fmodule-file=mod$((N-1)).pcm ... -o mod$N.pcm
```
Because `foo.modulemap` is read before reading any of the `.pcm` files,
we have to create a unique `FileID` for it when creating each module.
However, when reading the `.pcm` files, we will reuse the `FileID`
loaded from it for the same module map file and the `FileID` we created
can never be used again, but we will still mark it as affecting and it
will take the source location space in the output PCM.
For a chain of N dependencies, this results in the file taking `N *
(size of file)` source location space, which could be significant. For
examples, we observer internally that some targets that run out of 2GB
of source location space end up wasting up to 20% of that space in
module maps as described above.
I take extra care to still write the InputFile entries for those files that occupied
source location space before. It is required for correctness of clang-scan-deps.
This patch removes `ASTWriter::Context` and starts passing `ASTContext
&` explicitly to functions that actually need it. This is a
non-functional change with the end-goal of being able to write
lightweight PCM files with no `ASTContext` at all.
The 'allocator' modifier is now accepted in the 'allocate' clause. Added
LIT tests covering codegen, PCH, template handling, and serialization
for 'allocator' modifier.
Added support for allocator-modifier to release notes.
Testing
- New allocate modifier LIT tests.
- OpenMP LIT tests.
- check-all
- relevant sollve_vv test cases
tests/5.2/scope/test_scope_allocate_construct.c
This PR removes the `HeaderFileInfo::Framework` member and reduces the
size of this data type from 32B to 16B. This should improve Clang's
memory usage in situations where it keeps track of lots of header files.
NFCI. Depends on #114459.
This PR removes the `-index-header-map` functionality from Clang. AFAIK
this was only used internally at Apple and is now dead code. The main
motivation behind this change is to enable the removal of
`HeaderFileInfo::Framework` member and reducing the size of that data
structure.
rdar://84036149
With inferred modules, the dependency scanner takes care to replace the
fake "__inferred_module.map" path with the file that allowed the module
to be inferred. However, this only worked when such a module was
imported directly in the TU. Whenever such module got loaded
transitively, the scanner would fail to perform the replacement. This is
caused by the fact that PCM files are lossy and drop this information.
This patch makes sure that PCMs include this file for each submodule (in
the `SUBMODULE_DEFINITION` record), fixes one existing test with an
incorrect assertion, and does a little drive-by refactoring of
`ModuleMap`.
I noticed that some PCM files contain `HeaderFileInfo` for headers only
included in a dependent PCM file, which is wasteful.
This patch changes the logic to only write headers that are included
locally. This makes the PCM files smaller and saves some superfluous
deserialization of `HeaderFileInfo` triggered by
`Preprocessor::alreadyIncluded()`.
This patch shrinks the size of the `Module` class from 2112B to 1624B. I
wasn't able to get a good data on the actual impact on memory usage, but
given my `clang-scan-deps` workload at hand (with tens of thousands of
instances), I think there should be some win here. This also speeds up
my benchmark by under 0.1%.
Clang uses timestamp files to track the last time an implicitly-built
PCM file was verified to be up-to-date with regard to its inputs. With
`-fbuild-session-{file,timestamp}=` and
`-fmodules-validate-once-per-build-session` this reduces the number of
times a PCM file is checked per "build session".
The behavior I'm seeing with the current scheme is that when lots of
Clang instances wait for the same PCM to be built, they race to validate
it as soon as the file lock gets released, causing lots of concurrent
IO.
This patch makes it so that the timestamp is written by the same Clang
instance responsible for building the PCM while still holding the lock.
This makes it so that whenever a PCM file gets compiled, it's never
re-validated in the same build session.
I believe this is as sound as the current scheme. One thing to be aware
of is that there might be a time interval between accessing input file N
and writing the timestamp file, where changes to input files 0..<N would
not result in a rebuild. Since this is the case current scheme too, I'm
not too concerned about that.
I've seen this speed up `clang-scan-deps` by ~27%.
The 'vector' clause specifies the iterations to be executed in vector or
SIMD mode. There are some limitations on which associated compute
contexts may be associated with this and have arguments, but otherwise
this is a fairly unrestricted clause.
It DOES have region limits like 'gang' and 'worker'.
The worker clause specifies iterations of the loop/ that are executed in
parallel by distributing the iterations among the multiple works within
a single gang.
The sema rules for this type are simply that it cannot be combined with
a `kernel` construct with a `num_workers` clause, child `loop` clauses
cannot contain a `gang` or `worker` clause, and that the argument is oly
allowed when associated with a `kernel`.
The 'gang' clause is used to specify parallel execution of loops, thus
has some complicated rules depending on the 'loop's associated compute
construct. This patch implements all of those.
Add the permutation clause for the interchange directive which will be
introduced in the upcoming OpenMP 6.0 specification. A preview has been
published in
[Technical Report12](https://www.openmp.org/wp-content/uploads/openmp-TR12.pdf).
The 'tile' clause shares quite a bit of the rules with 'collapse', so a
followup patch will add those tests/behaviors. This patch deals with
adding the AST node.
The 'tile' clause takes a series of integer constant expressions, or *.
The asterisk is now represented by a new OpenACCAsteriskSizeExpr node,
else this clause is very similar to others.
- In Sema, when encountering Decls with function effects needing
verification, add them to a vector, DeclsWithEffectsToVerify.
- Update AST serialization to include DeclsWithEffectsToVerify.
- In AnalysisBasedWarnings, use DeclsWithEffectsToVerify as a work
queue, verifying functions with declared effects, and inferring (when
permitted and necessary) whether their callees have effects.
---------
Co-authored-by: Doug Wyatt <dwyatt@apple.com>
Co-authored-by: Sirraide <aeternalmail@gmail.com>
Co-authored-by: Erich Keane <ekeane@nvidia.com>
The 'collapse' clause on a 'loop' construct is used to specify how many
nested loops are associated with the 'loop' construct. It takes an
optional 'force' tag, and an integer constant expression as arguments.
There are many other restrictions based on the contents of the loop/etc,
but those are implemented in followup patches, for now, this patch just
adds the AST node and does basic argument checking on the loop-count.
Summary:
https://github.com/llvm/llvm-project/pull/109167 serializes
FunctionToLambdasMap in the order of pointers in DenseMap. It gives
different order with different memory layouts. Fix this issue by using
LocalDeclID instead of pointers.
Test Plan: check-clang
This reverts commit e39205654dc11c50bd117e8ccac243a641ebd71f.
There are further discussions in
https://github.com/llvm/llvm-project/pull/70976, happening for past two
weeks. Since there were no responses for couple weeks now, reverting
until author is back.
