Consider the following code:
```cpp
# 1 __FILE__ 1 3
export module a;
```
According to the wording in
[P1857R3](https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p1857r3.html):
```
A module directive may only appear as the first preprocessing tokens in a file (excluding the global module fragment.)
```
and the wording in
[[cpp.pre]](https://eel.is/c++draft/cpp.pre#nt:module-file)
```
module-file:
pp-global-module-fragment[opt] pp-module group[opt] pp-private-module-fragment[opt]
```
`#` is the first pp-token in the translation unit, and it was rejected
by clang, but they really should be exempted from this rule. The goal is
to not allow any preprocessor conditionals or most state changes, but
these don't fit that.
State change would mean most semantically observable preprocessor state,
particularly anything that is order dependent. Global flags like being a
system header/module shouldn't matter.
We should exempt a brunch of directives, even though it violates the
current standard wording.
In this patch, we introduce a `TrivialDirectiveTracer` to trace the
**State change** that described above and propose to exempt the
following kind of directive: `#line`, GNU line marker, `#ident`,
`#pragma comment`, `#pragma mark`, `#pragma detect_mismatch`, `#pragma
clang __debug`, `#pragma message`, `#pragma GCC warning`, `#pragma GCC
error`, `#pragma gcc diagnostic`, `#pragma OPENCL EXTENSION`, `#pragma
warning`, `#pragma execution_character_set`, `#pragma clang
assume_nonnull` and builtin macro expansion.
Fixes https://github.com/llvm/llvm-project/issues/145274
---------
Signed-off-by: yronglin <yronglin777@gmail.com>
(cherry picked from commit e6e874ce8f055f5b8c5d7f8c7fb0afe764d1d350)
This reverts commit e2a885537f11f8d9ced1c80c2c90069ab5adeb1d. Build failures were fixed right away and reverting the original commit without the fixes breaks the build again.
The `DiagnosticOptions` class is currently intrusively
reference-counted, which makes reasoning about its lifetime very
difficult in some cases. For example, `CompilerInvocation` owns the
`DiagnosticOptions` instance (wrapped in `llvm::IntrusiveRefCntPtr`) and
only exposes an accessor returning `DiagnosticOptions &`. One would
think this gives `CompilerInvocation` exclusive ownership of the object,
but that's not the case:
```c++
void shareOwnership(CompilerInvocation &CI) {
llvm::IntrusiveRefCntPtr<DiagnosticOptions> CoOwner = &CI.getDiagnosticOptions();
// ...
}
```
This is a perfectly valid pattern that is being actually used in the
codebase.
I would like to ensure the ownership of `DiagnosticOptions` by
`CompilerInvocation` is guaranteed to be exclusive. This can be
leveraged for a copy-on-write optimization later on. This PR changes
usages of `DiagnosticOptions` across `clang`, `clang-tools-extra` and
`lldb` to not be intrusively reference-counted.
This PR hides the reference-counted pointer that holds `TargetOptions`
from the public API of `CompilerInvocation`. This gives
`CompilerInvocation` an exclusive control over the lifetime of this
member, which will eventually be leveraged to implement a copy-on-write
behavior.
There are two clients that currently share ownership of that pointer:
* `TargetInfo` - This was refactored to hold a non-owning reference to
`TargetOptions`. The options object is typically owned by the
`CompilerInvocation` or by the new `CompilerInstance::AuxTargetOpts` for
the auxiliary target. This needed a bit of care in `ASTUnit::Parse()` to
keep the `CompilerInvocation` alive.
* `clangd::PreambleData` - This was refactored to exclusively own the
`TargetOptions` that get moved out of the `CompilerInvocation`.
This makes it so that `CompilerInvocation` can be the only entity that
manages ownership of `HeaderSearchOptions`, making it possible to
implement copy-on-write semantics.
This new method repeatedly calls Lex() until end of file is reached
and optionally fills a std::vector of Tokens. Use it in Clang's unit
tests to avoid quite some code duplication.
Differential Revision: https://reviews.llvm.org/D158413
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.
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
