[clang][modules] Delay creating `IdentifierInfo` for names of explicit modules

When using explicit Clang modules, some declarations might unexpectedly become invisible.

This is caused by the mechan

[clang][modules] Delay creating `IdentifierInfo` for names of explicit modules

When using explicit Clang modules, some declarations might unexpectedly become invisible.

This is caused by the mechanism that loads PCM files passed via `-fmodule-file=<path>` and creates an `IdentifierInfo` for the module name. The `IdentifierInfo` creation takes place when the `ASTReader` is in a weird state, with modules that are loaded but not yet set up properly. This patch delays the creation of `IdentifierInfo` until the `ASTReader` is done with reading the PCM.

Note that the `-fmodule-file=<name>=<path>` form of the argument doesn't suffer from this issue, since it doesn't create `IdentifierInfo` for the module name.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D111543

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[clang] Use llvm::erase_if (NFC)

[clang][modules] Cache loads of modules imported by PCH

During explicit modular build, PCM files are typically specified via the `-fmodule-file=<path>` command-line option. Early during the compilat

[clang][modules] Cache loads of modules imported by PCH

During explicit modular build, PCM files are typically specified via the `-fmodule-file=<path>` command-line option. Early during the compilation, Clang uses the `ASTReader` to read their contents and caches the result so that the module isn't loaded implicitly later on. A listener is attached to the `ASTReader` to collect names of the modules read from the PCM files. However, if the PCM has already been loaded previously via PCH:
1. the `ASTReader` doesn't do anything for the second time,
2. the listener is not invoked at all,
3. the module load result is not cached,
4. the compilation fails when attempting to load the module implicitly later on.

This patch solves this problem by attaching the listener to the `ASTReader` for PCH reading as well.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D111560

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[clang] NFC: Move class to make it reusable

This is a prep patch for D111560.

[clang][modules] NFC: Propagate import `SourceLocation` into `HeaderSearch::lookupModule`

This patch propagates the import `SourceLocation` into `HeaderSearch::lookupModule`. This enables remarks on

[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

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Reland "[clang-repl] Allow loading of plugins in clang-repl."

Differential revision: https://reviews.llvm.org/D110484

Revert "[clang-repl] Allow loading of plugins in clang-repl."

This reverts commit 81fb640f83b6a5d099f9124739ab3049be79ea56 due to bot failures:
https://lab.llvm.org/buildbot#builders/57/builds/10807

[clang-repl] Allow loading of plugins in clang-repl.

Differential revision: https://reviews.llvm.org/D110484

[clang] Remove redundant calls to c_str() (NFC)

Identified with readability-redundant-string-cstr.

Frontend: Add -f{,no-}implicit-modules-uses-lock and -Rmodule-lock

Add -cc1 flags `-fmodules-uses-lock` and `-fno-modules-uses-lock` to
allow the lock manager to be turned off when building implicit

Frontend: Add -f{,no-}implicit-modules-uses-lock and -Rmodule-lock

Add -cc1 flags `-fmodules-uses-lock` and `-fno-modules-uses-lock` to
allow the lock manager to be turned off when building implicit modules.

Add `-Rmodule-lock` so that we can see when it's being used.

Differential Revision: https://reviews.llvm.org/D95583

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Frontend: Refactor compileModuleAndReadAST, NFC

This renames `compileModuleAndReadAST`, adding a `BehindLock` suffix,
and refactors it to significantly reduce nesting.

- Split out helpers `compileM

Frontend: Refactor compileModuleAndReadAST, NFC

This renames `compileModuleAndReadAST`, adding a `BehindLock` suffix,
and refactors it to significantly reduce nesting.

- Split out helpers `compileModuleAndReadASTImpl` and
`readASTAfterCompileModule` which have straight-line code that doesn't
worry about locks.
- Use `break` in the interesting cases of `switch` statements to reduce
nesting.
- Use early `return`s to reduce nesting.

Detangling the compile-and-read logic from the check-for-locks logic
should be a net win for readability, although I also have a side
motivation of making the locks optional in a follow-up.

No functionality change here.

Differential Revision: https://reviews.llvm.org/D95581

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[Frontend] Only compile modules if not already finalized

It was possible to re-add a module to a shared in-memory module cache
when search paths are changed. This can eventually cause a crash if the

[Frontend] Only compile modules if not already finalized

It was possible to re-add a module to a shared in-memory module cache
when search paths are changed. This can eventually cause a crash if the
original module is referenced after this occurs.
1. Module A depends on B
2. B exists in two paths C and D
3. First run only has C on the search path, finds A and B and loads
them
4. Second run adds D to the front of the search path. A is loaded and
contains a reference to the already compiled module from C. But
searching finds the module from D instead, causing a mismatch
5. B and the modules that depend on it are considered out of date and
thus rebuilt
6. The recompiled module A is added to the in-memory cache, freeing
the previously inserted one

This can never occur from a regular clang process, but is very easy to
do through the API - whether through the use of a shared case or just
running multiple compilations from a single `CompilerInstance`. Update
the compilation to return early if a module is already finalized so that
the pre-condition in the in-memory module cache holds.

Resolves rdar://78180255

Differential Revision: https://reviews.llvm.org/D105328

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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

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

show more ...

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

This reverts commit 6775fc6ffa3ca1c36b20c25fa4e7f48f81213cf2.

It also reverts "[lldb] Fix compilation by adjusting to t

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

show more ...

[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

[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

show more ...

[clang][PATCH][nfc] Refactor TargetInfo::adjust to pass DiagnosticsEngine to allow diagnostics on target-unsupported options

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.o

[clang][PATCH][nfc] Refactor TargetInfo::adjust to pass DiagnosticsEngine to allow diagnostics on target-unsupported options

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D104729

show more ...

Revert "[clang][PATCH][nfc] Refactor TargetInfo::adjust to pass DiagnosticsEngine to allow diagnostics on target-unsupported options"

This reverts commit 2dbe1c675fe94eeb7973dcc25b049d25f4ca4fa0.
Mo

Revert "[clang][PATCH][nfc] Refactor TargetInfo::adjust to pass DiagnosticsEngine to allow diagnostics on target-unsupported options"

This reverts commit 2dbe1c675fe94eeb7973dcc25b049d25f4ca4fa0.
More buildbot failures

show more ...

[clang][PATCH][nfc] Refactor TargetInfo::adjust to pass DiagnosticsEngine to allow diagnostics on target-unsupported options

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.o

[clang][PATCH][nfc] Refactor TargetInfo::adjust to pass DiagnosticsEngine to allow diagnostics on target-unsupported options

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D104729

show more ...

Revert "[clang][PATCH][nfc] Refactor TargetInfo::adjust to pass DiagnosticsEngine to allow diagnostics on target-unsupported options"

This reverts commit 2c02b0c3f45414ac6c64583e006a26113c028304.
bu

Revert "[clang][PATCH][nfc] Refactor TargetInfo::adjust to pass DiagnosticsEngine to allow diagnostics on target-unsupported options"

This reverts commit 2c02b0c3f45414ac6c64583e006a26113c028304.
buildbot fails

show more ...

[clang][PATCH][nfc] Refactor TargetInfo::adjust to pass DiagnosticsEngine to allow diagnostics on target-unsupported options

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.o

[clang][PATCH][nfc] Refactor TargetInfo::adjust to pass DiagnosticsEngine to allow diagnostics on target-unsupported options

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D104729

show more ...

Frontend: Respect -fno-temp-file when creating a PCH

When creating a PCH file the use of a temp file will be dictated by the
presence or absence of the -fno-temp-file flag. Creating a module file
wi

Frontend: Respect -fno-temp-file when creating a PCH

When creating a PCH file the use of a temp file will be dictated by the
presence or absence of the -fno-temp-file flag. Creating a module file
will always use a temp file via the new ForceUseTemporary flag.

This fixes bug 50033.

show more ...

Fix to Windows temp file change.

Original change passed wrong parameters to the raw_fd_ostream ctor.
Fixes a bug in https://reviews.llvm.org/D102736.

[SystemZ][z/OS] Pass OpenFlags when creating tmp files

This patch https://reviews.llvm.org/D102876 caused some lit regressions on z/OS because tmp files were no longer being opened based on binary/t

[SystemZ][z/OS] Pass OpenFlags when creating tmp files

This patch https://reviews.llvm.org/D102876 caused some lit regressions on z/OS because tmp files were no longer being opened based on binary/text mode. This patch passes OpenFlags when creating tmp files so we can open files in different modes.

Reviewed By: amccarth

Differential Revision: https://reviews.llvm.org/D103806

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Recommit "Fix tmp files being left on Windows builds." with a fix for
incorrect std::string use. (Also remove redundant call to
RemoveFileOnSignal.)

Clang writes object files by first writing to a .

Recommit "Fix tmp files being left on Windows builds." with a fix for
incorrect std::string use. (Also remove redundant call to
RemoveFileOnSignal.)

Clang writes object files by first writing to a .tmp file and then
renaming to the final .obj name. On Windows, if a compile is killed
partway through the .tmp files don't get deleted.

Currently it seems like RemoveFileOnSignal takes care of deleting the
tmp files on Linux, but on Windows we need to call
setDeleteDisposition on tmp files so that they are deleted when
closed.

This patch switches to using TempFile to create the .tmp files we write
when creating object files, since it uses setDeleteDisposition on Windows.
This change applies to both Linux and Windows for consistency.

Differential Revision: https://reviews.llvm.org/D102876

This reverts commit 20797b129f844d4b12ffb2b12cf33baa2d42985c.

show more ...

Revert "Fix tmp files being left on Windows builds." for now;
causing some asan test failures.

This reverts commit 7daa18215905c831e130c7542f17619e9d936dfc.