Recently, there are multiple false positive issue reports about the
reachability of implementation partition units:
- https://github.com/llvm/llvm-project/issues/105882
- https://github.com/llvm/llvm-project/issues/101348
- https://lists.isocpp.org/core/2024/08/16232.php
And according to our use experience for modules, we find it is a pretty
good practice to not import implementation partition units in the
interface units. It can help developers to have a pretty good mental
model for when to use an implementation partition unit: that any unit in
the module but not in the module interfaces can be in the implementation
partition unit.
So I think it is good to add the diagnostics.
Implements `export` keyword in HLSL.
There are two ways the `export` keyword can be used:
1. On individual function declarations
```
export void f() {}
```
2. On a group of function declaration:
```
export {
void f1();
void f2() {}
}
```
Functions declared with the `export` keyword have external linkage. The
implementation does not include validation of when a function can or
cannot be exported, such as when it has resource argument or semantic
annotations. That will be covered by llvm/llvm-project#93330.
Currently all function declarations in global or named namespaces have
external linkage by default so there are no specific code changes
required right now to make sure exported function have external linkage
as well. That will change as part of llvm/llvm-project#92071. Any
additional changes to make sure exported functions still have external
linkage will be done as part of this work item.
Fixes#92812
This patch moves documentation of `Sema` functions from `.cpp` files to `Sema.h` when there was no documentation in the latter, or it can be trivially subsumed. More complicated cases when there's less trivial divergence between documentation attached to declaration and the one attached to implementation are left for a later PR that would require review.
It appears that doxygen can find the documentation for a function defined out-of-line even if it's attached to an implementation, and not declaration. But other tools, e.g. clangd, are not as powerful. So this patch significantly improves autocompletion experience for (at least) clangd-based IDEs.
This patch extracts the logci to decide how we decide the module units
belongs to the same module into a member function of ASTContext. This is
helpful to refactor the implementation in the future.
Reduced BMI
Mitigate https://github.com/llvm/llvm-project/issues/61447
The root cause of the above problem is that when we write a declaration,
we need to lookup all the redeclarations in the imported modules. Then
it will be pretty slow if there are too many redeclarations in different
modules. This patch doesn't solve the porblem.
What the patchs mitigated is, when we writing a named module, we shouldn't
write the declarations from GMF if it is unreferenced **in current
module unit**. The difference here is that, if the declaration is used
in the imported modules, we used to emit it as an update. But we
definitely want to avoid that after this patch.
For that reproducer in
https://github.com/llvm/llvm-project/issues/61447, it used to take 2.5s
to compile and now it only takes 0.49s to compile, which is a big win.
This patch tries to make the boundary of clang module and C++20 named
module more clear.
The changes included:
- Rename `TranslationUnitKind::TU_Module` to
`TranslationUnitKind::TU_ClangModule`.
- Rename `Sema::ActOnModuleInclude` to `Sema::ActOnAnnotModuleInclude`.
- Rename `ActOnModuleBegin` to `Sema::ActOnAnnotModuleBegin`.
- Rename `Sema::ActOnModuleEnd` to `Sema::ActOnAnnotModuleEnd`.
- Removes a warning if we're trying to compile a non-module unit as
C++20 module unit. This is not actually useful and makes (the future)
implementation unnecessarily complex.
This patch meant to be a NFC fix. But it shows that it fixed a bug
suprisingly that previously we would surppress the unused-value warning
in named modules. Because it shares the same logic with clang modules,
which has headers semantics. This shows the change is meaningful.
Close https://github.com/llvm/llvm-project/issues/84002
Per [module.import]p7:
> Additionally, when a module-import-declaration in a module unit of
> some module M imports another module unit U of M, it also imports all
> translation units imported by non-exported module-import-declarations
> in the module unit purview of U.
However, we only tried to implement it during the implicit import of
primary module interface for module implementation unit.
Also we didn't implement the last sentence from [module.import]p7
completely:
> These rules can in turn lead to the importation of yet more
> translation units.
This patch tries to care the both issues.
Previously we forbiden the users to import named modules from clang header
modules. However, due to an oversight, the @import form of Objective C
got involved. This is not want and we fix that in this patch.
This patch replaces uses of StringRef::{starts,ends}with with
StringRef::{starts,ends}_with for consistency with
std::{string,string_view}::{starts,ends}_with in C++20.
I'm planning to deprecate and eventually remove
StringRef::{starts,ends}with.
Close https://github.com/llvm/llvm-project/issues/71347
Previously I misread the concept of module purview. I thought if a
declaration attached to a unnamed module, it can't be part of the module
purview. But after the issue report, I recognized that module purview is
more of a concept about locations instead of semantics.
Concretely, the things in the language linkage after module declarations
can be exported.
This patch refactors `Module::isModulePurview()` and introduces some
possible code cleanups.
The 'ModuleInterface' in Sema::ModuleScope is confusing. It actually
means 'not implementation'. This patch removes that bit and extract the
information from the recorded clang::Module.
This patch introduces a new enumerator `Invalid = 0`, shifting other enumerators by +1. Contrary to how it might sound, this actually affirms status quo of how this enum is stored in `clang::Decl`:
```
/// If 0, we have not computed the linkage of this declaration.
/// Otherwise, it is the linkage + 1.
mutable unsigned CacheValidAndLinkage : 3;
```
This patch makes debuggers to not be mistaken about enumerator stored in this bit-field. It also converts `clang::Linkage` to a scoped enum.
This patch converts `LinkageSpecDecl::LanguageIDs` into scoped enum, and moves it to namespace scope, so that it can be forward-declared where required.
This reapplies ddbcc10b9e26b18f6a70e23d0611b9da75ffa52f, except for a tiny part that was reverted separately: 65331da0032ab4253a4bc0ddcb2da67664bd86a9. That will be reapplied later on, since it turned out to be more involved.
This commit is enabled by 5523fefb01c282c4cbcaf6314a9aaf658c6c145f and f0f548a65a215c450d956dbcedb03656449705b9, specifically the part that makes 'clang-tidy/checkers/misc/header-include-cycle.cpp' separator agnostic.
This commit replaces some calls to the deprecated `FileEntry::getName()` with `FileEntryRef::getName()` by swapping current usages of `SourceManager::getFileEntryForID()` with `SourceManager::getFileEntryRefForID()`. This lowers the number of usages of the deprecated `FileEntry::getName()` from 95 to 50.
Close https://github.com/llvm/llvm-project/issues/64755
This wouldn't affect the form @import as the test shows. The two
affected test case `diag-flags.cpp` and `diag-pragma.cpp` are old test
cases in 2017 and 2018, when we're not so clear about the direction of
modules. And the things that these 2 tests tested can be covered by
clang modules naturally. So I change the them into clang modules to
not block this patch.
In preparation for removing the `#include "llvm/ADT/StringExtras.h"`
from the header to source file of `llvm/Support/Error.h`, first add in
all the missing includes that were previously included transitively
through this header.
The following test fails to compile TU b.cpp because we are not making the transitively imported modules visible (per [module.import]/p7)
```
a.cppm:
export module a;
export int foo() {
return 42;
}
b.cppm:
export module b;
import a;
export int bar();
b.cpp:
module b;
int bar() {
return foo();
}
clang++ -c -std=c++2b -fmodule-output a.cppm
clang++ -c -std=c++2b -fmodule-output -fprebuilt-module-path=. b.cppm
clang++ -c -std=c++2b -fprebuilt-module-path=. b.cpp
b.cpp:4:12: error: declaration of 'foo' must be imported from module 'a' before it is required
return foo();
```
This is fixed by the following patch (which also addresses a FIXME in basic.def.odr/p6.cppm).
Differential Revision: https://reviews.llvm.org/D152746
It has been reported to that the current clang errors for, specifically,
static_assert in export contexts are a serious blocker to adoption of
modules in some cases.
There is also implementation divergence with GCC and MSVC allowing the
constructs mentioned below where clang currently rejects them with an
error.
The category of errors [for declarations in an exported context] is:
(unnamed, static_assert, empty and asm decls). These are now permitted
after P2615R1 which was approved by WG21 as a DR (and thus should be
applied to C++20 as well).
This patch removes these diagnostics and amends the testsuite accordingly.
Differential Revision: https://reviews.llvm.org/D152946
When modules are disabled, there's no loaded module for these import
decls to point at. This results in crashes when there are modulemap
files but no -fmodules flag (this configuration is used for layering
check violations).
This patch makes sure import declarations are introduced only when
modules are enabled, which makes this case similar to textual headers
(no import decls are created for #include of textual headers from a
modulemap).
Differential Revision: https://reviews.llvm.org/D152274
Decl::isInAnotherModuleUnit
Refactor `Sema::isModuleUnitOfCurrentTU` to `Decl::isInAnotherModuleUnit`
to make code simpler a little bit. Note that although this patch
introduces a FIXME, this is an existing issue and this patch just tries
to describe it explicitly.
Currently, the header units are rarely used and it is not well tested.
To avoid further misunderstandings, let's mark it as experimental and
emit a warning when users wants to import it.
This is discussed in modules developers meeting.
The original name "ASTContext::getNamedModuleForCodeGen" is not properly
reflecting the usage of the interface. This interface can be used to
judge the current module unit in both sema analysis and code generation.
So the original name was not so correct.
Decl::isInCurrentModuleUnit
Refactor `Sema::isModuleUnitOfCurrentTU` to `Decl::isInCurrentModuleUnit`
to make code simpler a little bit. Note that although this patch
introduces a FIXME, this is an existing issue and this patch just tries
to describe it explicitly.
During the ISO C++ Committee meeting plenary session the C++23 Standard
has been voted as technical complete.
This updates the reference to c++2b to c++23 and updates the __cplusplus
macro.
Drive-by fixes c++1z -> c++17 and c++2a -> c++20 when seen.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D149553
Close https://github.com/llvm/llvm-project/issues/62112
In the previous change, we'll stop parsing directly after we found
reserved module names. But this may be too aggressive. This patch
changes this. Note that the parsing will still be stopped if the module
name is `module` or `import`.
We need to be able to distinguish individual TUs from the same module in cases
where TU-local entities either need to be hidden (or, for some cases of ADL in
template instantiation, need to be detected as exposures).
This creates a module type for the implementation which implicitly imports its
primary module interface per C++20:
[module.unit/8] 'A module-declaration that contains neither an export-keyword
nor a module-partition implicitly imports the primary module interface unit of
the module as if by a module-import-declaration.
Implementation modules are never serialized (-emit-module-interface for an
implementation unit is diagnosed and rejected).
Differential Revision: https://reviews.llvm.org/D126959
Any project that wants to import std; potentially needs to be able to
build a module that does export std;. We silenced the error diagnostic
if the module identified itself as a system header, but this isn't
quite good enough, what we really need is a way to identify a system
module. It would be nice for that feature to be shared among the major
implementations, so this downgrades the diagnostic from an error to a
warning temporarily to give implementers time to determine what that
mechanism will look like. We may convert this warning back into an
error in a future release of Clang, but it's not guaranteed we will do
so.
Fixes https://github.com/llvm/llvm-project/issues/61446
Differential Revision: https://reviews.llvm.org/D146986
This reverts commit c6e9823724ef6bdfee262289ee34d162db436af0.
Reason: Broke the ASan buildbots, see https://reviews.llvm.org/D126959
(the original phabricator review) for more info.
We need to be able to distinguish individual TUs from the same module in cases
where TU-local entities either need to be hidden (or, for some cases of ADL in
template instantiation, need to be detected as exposures).
This creates a module type for the implementation which implicitly imports its
primary module interface per C++20:
[module.unit/8] 'A module-declaration that contains neither an export-keyword
nor a module-partition implicitly imports the primary module interface unit of
the module as if by a module-import-declaration.
Implementation modules are never serialized (-emit-module-interface for an
implementation unit is diagnosed and rejected).
Differential Revision: https://reviews.llvm.org/D126959
Close https://github.com/llvm/llvm-project/issues/60405
See the discussion in the above link for the background.
What the patch does:
- Rename `Module::ModuleKind::GlobalModuleFragment` to
`Module::ModuleKind::ExplicitGlobalModuleFragment`.
- Add another module kind `ImplicitGlobalModuleFragment` to
`ModuleKind`.
- Create an implicit global module fragment for the language linkage
declarations inside a module purview.
- If the language linkage lives inside the scope of an export decl,
the created modules is marked as exported to outer modules.
- In fact, Sema will only create at most 2 implicit global module
fragments to avoid creating a lot of unnecessary modules in the edging
case.
Reviewed By: iains
Differential Revision: https://reviews.llvm.org/D144367
As the diagnostic message shows, we should remove -fmodules-ts flag in
clang/llvm17. Since clang/llvm16 is already branched. We can remove the
depreacared flag now.
Previously we'll set the named modules for ASTContext in ParseAST. But
this is not intuitive and we need comments to tell the intuition. This
patch moves the code the right the place, where the corrresponding
module is first created/loaded. Now it is more intuitive and we can use
the value in the earlier places.
Close https://github.com/llvm/llvm-project/issues/57293.
Previsouly we can't use `-fmodule-file=<module-name>=<BMI-Path>` for
implementation units, it is a bug. Also the behavior of the above option
is not tested nor documented for C++20 Modules. This patch addresses the
2 problems.
Whenever we are compiling implementation of a framework (with the `-fmodule-name=FW` option), we never translate `#import <FW/Header.h>` to an import, regardless of whether "Header.h" belongs to "FW" or "FW_Private". For the same reasons, we also disallow `@import FW`. However, we still allow `@import FW_Private`. This patch disallows that a well, to be consistent with the rest of the rules.
Reviewed By: benlangmuir
Differential Revision: https://reviews.llvm.org/D142167
Refactor the `Module::Header` class to use an `OptionalFileEntryRef`
instead of a `FileEntry*`. This is preparation for refactoring the
`TopHeaderNames` to use `FileEntryRef` so that we preserve the
lookup path of the headers when serializing.
This is mostly based on https://reviews.llvm.org/D90497
Reviewed By: jansvoboda11
Differential Revision: https://reviews.llvm.org/D142113
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
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).
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
