Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit 7c51f02effdbd0d5e12bfd26f9c3b2ab5687c93f because it
stills breaks the LLDB tests. This was re-landed wi

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit 7c51f02effdbd0d5e12bfd26f9c3b2ab5687c93f because it
stills breaks the LLDB tests. This was re-landed without addressing the
issue or even agreement on how to address the issue. More details and
discussion in https://reviews.llvm.org/D112374.

show more ...

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which go

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.

The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.

An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.

---

Troubleshooting list to deal with any breakage seen with this patch:

1) The most likely effect one would see by this patch is a change in how
a type is printed. The type printer will, by design and default,
print types as written. There are customization options there, but
not that many, and they mainly apply to how to print a type that we
somehow failed to track how it was written. This patch fixes a
problem where we failed to distinguish between a type
that was written without any elaborated-type qualifiers,
such as a 'struct'/'class' tags and name spacifiers such as 'std::',
and one that has been stripped of any 'metadata' that identifies such,
the so called canonical types.
Example:
```
namespace foo {
struct A {};
A a;
};
```
If one were to print the type of `foo::a`, prior to this patch, this
would result in `foo::A`. This is how the type printer would have,
by default, printed the canonical type of A as well.
As soon as you add any name qualifiers to A, the type printer would
suddenly start accurately printing the type as written. This patch
will make it print it accurately even when written without
qualifiers, so we will just print `A` for the initial example, as
the user did not really write that `foo::` namespace qualifier.

2) This patch could expose a bug in some AST matcher. Matching types
is harder to get right when there is sugar involved. For example,
if you want to match a type against being a pointer to some type A,
then you have to account for getting a type that is sugar for a
pointer to A, or being a pointer to sugar to A, or both! Usually
you would get the second part wrong, and this would work for a
very simple test where you don't use any name qualifiers, but
you would discover is broken when you do. The usual fix is to
either use the matcher which strips sugar, which is annoying
to use as for example if you match an N level pointer, you have
to put N+1 such matchers in there, beginning to end and between
all those levels. But in a lot of cases, if the property you want
to match is present in the canonical type, it's easier and faster
to just match on that... This goes with what is said in 1), if
you want to match against the name of a type, and you want
the name string to be something stable, perhaps matching on
the name of the canonical type is the better choice.

3) This patch could exposed a bug in how you get the source range of some
TypeLoc. For some reason, a lot of code is using getLocalSourceRange(),
which only looks at the given TypeLoc node. This patch introduces a new,
and more common TypeLoc node which contains no source locations on itself.
This is not an inovation here, and some other, more rare TypeLoc nodes could
also have this property, but if you use getLocalSourceRange on them, it's not
going to return any valid locations, because it doesn't have any. The right fix
here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive
into the inner TypeLoc to get the source range if it doesn't find it on the
top level one. You can use getLocalSourceRange if you are really into
micro-optimizations and you have some outside knowledge that the TypeLocs you are
dealing with will always include some source location.

4) Exposed a bug somewhere in the use of the normal clang type class API, where you
have some type, you want to see if that type is some particular kind, you try a
`dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an
ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match.
Again, like 2), this would usually have been tested poorly with some simple tests with
no qualifications, and would have been broken had there been any other kind of type sugar,
be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType.
The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper
into the type. Or use `getAsAdjusted` when dealing with TypeLocs.
For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast.

5) It could be a bug in this patch perhaps.

Let me know if you need any help!

Signed-off-by: Matheus Izvekov <[email protected]>

Differential Revision: https://reviews.llvm.org/D112374

show more ...

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit bdc6974f92304f4ed542241b9b89ba58ba6b20aa because it
breaks all the LLDB tests that import the std module

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit bdc6974f92304f4ed542241b9b89ba58ba6b20aa because it
breaks all the LLDB tests that import the std module.

import-std-module/array.TestArrayFromStdModule.py
import-std-module/deque-basic.TestDequeFromStdModule.py
import-std-module/deque-dbg-info-content.TestDbgInfoContentDequeFromStdModule.py
import-std-module/forward_list.TestForwardListFromStdModule.py
import-std-module/forward_list-dbg-info-content.TestDbgInfoContentForwardListFromStdModule.py
import-std-module/list.TestListFromStdModule.py
import-std-module/list-dbg-info-content.TestDbgInfoContentListFromStdModule.py
import-std-module/queue.TestQueueFromStdModule.py
import-std-module/stack.TestStackFromStdModule.py
import-std-module/vector.TestVectorFromStdModule.py
import-std-module/vector-bool.TestVectorBoolFromStdModule.py
import-std-module/vector-dbg-info-content.TestDbgInfoContentVectorFromStdModule.py
import-std-module/vector-of-vectors.TestVectorOfVectorsFromStdModule.py

https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/45301/

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[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which go

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.

The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.

An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.

Signed-off-by: Matheus Izvekov <[email protected]>

Differential Revision: https://reviews.llvm.org/D112374

show more ...

[Sema] Remove location from implicit capture init expr

A lambda's closure is initialized when the lambda is declared. For
implicit captures, the initialization code emitted from EmitLambdaExpr
refer

[Sema] Remove location from implicit capture init expr

A lambda's closure is initialized when the lambda is declared. For
implicit captures, the initialization code emitted from EmitLambdaExpr
references source locations *within the lambda body* in the function
containing the lambda. This results in a poor debugging experience: we
step to the line containing the lambda, then into lambda, out again,
over and over, until every capture's field is initialized.

To improve stepping behavior, assign the starting location of the lambda
to expressions which initialize an implicit capture within it.

rdar://39807527

Differential Revision: https://reviews.llvm.org/D50927

llvm-svn: 342194

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Require the type of a by-copy capture to be complete before creating its field.

The problem here is more serious than the fix implies. Adding a field
to a class updates the triviality bits for the c

Require the type of a by-copy capture to be complete before creating its field.

The problem here is more serious than the fix implies. Adding a field
to a class updates the triviality bits for the class (among other
things). Failing to require a complete type before adding the field
meant that these updates don't happen in the well-formed case where
the capture is an uninstantiated class template specialization,
leading the lambda itself to be treated as having a trivial copy
constructor when it shouldn't. Fixes <rdar://problem/15560464>.

llvm-svn: 197623

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Diagnose by-copy captures of abstract classes.

Fixes <rdar://problem/14468891>.

llvm-svn: 192419

When capturing 'this' in a lambda, make sure to update the set of
array-index starting values for the 'this' capture. Fixes
<rdar://problem/12426831>.

llvm-svn: 166709

A little more lambda capture initialization diagnostics cleanup

llvm-svn: 150589

Introduce a new initialization entity for lambda captures, and
specialize location information and diagnostics for this entity.

llvm-svn: 150588

Make sure Sema creates a field for 'this' captures. (Doug, please double-check that this is correct.)

llvm-svn: 150292

Remove the "unsupported" error for lambda expressions. It's annoying,
and rapidly becoming untrue.

llvm-svn: 150165

Implement capture-by-copy for arrays in lambdas.

llvm-svn: 150138

When we create a non-static data member in the closure object for a
capture, make sure we actually add the field.

llvm-svn: 150135

Various interrelated cleanups for lambdas:
- Complete the lambda class when we finish the lambda expression
(previously, it was left in the "being completed" state)
- Actually return the Lamb

Various interrelated cleanups for lambdas:
- Complete the lambda class when we finish the lambda expression
(previously, it was left in the "being completed" state)
- Actually return the LambdaExpr object and bind to the resulting
temporary when needed.
- Detect when cleanups are needed while capturing a variable into a
lambda (e.g., due to default arguments in the copy constructor), and
make sure those cleanups apply for the whole of the lambda
expression.


llvm-svn: 150123

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Introduce basic ASTs for lambda expressions. This covers:
- Capturing variables by-reference and by-copy within a lambda
- The representation of lambda captures
- The creation of the non-static

Introduce basic ASTs for lambda expressions. This covers:
- Capturing variables by-reference and by-copy within a lambda
- The representation of lambda captures
- The creation of the non-static data members in the lambda class
that store the captured variables
- The initialization of the non-static data members from the
captured variables
- Pretty-printing lambda expressions

There are a number of FIXMEs, both explicit and implied, including:
- Creating a field for a capture of 'this'
- Improved diagnostics for initialization failures when capturing
variables by copy
- Dealing with temporaries created during said initialization
- Template instantiation
- AST (de-)serialization
- Binding and returning the lambda expression; turning it into a
proper temporary
- Lots and lots of semantic constraints
- Parameter pack captures

llvm-svn: 149977

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