[clang] [Sema] Preserve nested name specifier prefix in MemberPointerType (#118236)

Fixes https://github.com/llvm/llvm-project/issues/118198
Fixes https://github.com/clangd/clangd/issues/2235

[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 expose 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 <mizvekov@gmail.com>

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

show more ...

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 <mizvekov@gmail.com>

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/

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.

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

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

show more ...

Model type attributes as regular Attrs.

Specifically, AttributedType now tracks a regular attr::Kind rather than
having its own parallel Kind enumeration, and AttributedTypeLoc now
holds an Attr* in

Model type attributes as regular Attrs.

Specifically, AttributedType now tracks a regular attr::Kind rather than
having its own parallel Kind enumeration, and AttributedTypeLoc now
holds an Attr* instead of holding an ad-hoc collection of Attr fields.

Differential Revision: https://reviews.llvm.org/D50526

This reinstates r339623, reverted in r339638, with a fix to not fail
template instantiation if we instantiate a QualType with no associated
type source information and we encounter an AttributedType.

llvm-svn: 340215

show more ...

Print nested name specifiers for typedefs and type aliases

Printing typedefs or type aliases using clang_getTypeSpelling() is missing the
namespace they are defined in. This is in contrast to other

Print nested name specifiers for typedefs and type aliases

Printing typedefs or type aliases using clang_getTypeSpelling() is missing the
namespace they are defined in. This is in contrast to other types that always
yield the full typename including namespaces.

Patch by Michael Reiher!

Differential Revision: https://reviews.llvm.org/D29944

llvm-svn: 297465

show more ...

[MS Compat] Adjust thiscall to cdecl when deducing template arguments

Function types can be extracted from member pointer types.
However, the type is not appropriate without first adjusting the call

[MS Compat] Adjust thiscall to cdecl when deducing template arguments

Function types can be extracted from member pointer types.
However, the type is not appropriate without first adjusting the calling
convention.

This fixes PR25661.

llvm-svn: 254323

show more ...

Remove the -cxx-abi command-line flag.

This makes the C++ ABI depend entirely on the target: MS ABI for -win32 triples,
Itanium otherwise. It's no longer possible to do weird combinations.

To be ab

Remove the -cxx-abi command-line flag.

This makes the C++ ABI depend entirely on the target: MS ABI for -win32 triples,
Itanium otherwise. It's no longer possible to do weird combinations.

To be able to run a test with a specific ABI without constraining it to a
specific triple, new substitutions are added to lit: %itanium_abi_triple and
%ms_abi_triple can be used to get the current target triple adjusted to the
desired ABI. For example, if the test suite is running with the i686-pc-win32
target, %itanium_abi_triple will expand to i686-pc-mingw32.

Differential Revision: http://llvm-reviews.chandlerc.com/D2545

llvm-svn: 199250

show more ...

Add an AdjustedType sugar node for adjusting calling conventions

Summary:
In general, this type node can be used to represent any type adjustment
that occurs implicitly without losing type sugar. T

Add an AdjustedType sugar node for adjusting calling conventions

Summary:
In general, this type node can be used to represent any type adjustment
that occurs implicitly without losing type sugar. The immediate use of
this is to adjust the calling conventions of member function pointer
types without breaking template instantiation.

Fixes PR17996.

Reviewers: rsmith

Differential Revision: http://llvm-reviews.chandlerc.com/D2332

llvm-svn: 196451

show more ...

Tighten diagnostics for calling conventions on variadic functions

Follow-up from r192240.

This makes it an error to use callee-cleanup conventions on variadic
functions, except for __fastcall and _

Tighten diagnostics for calling conventions on variadic functions

Follow-up from r192240.

This makes it an error to use callee-cleanup conventions on variadic
functions, except for __fastcall and __stdcall, which we ignore with
a warning for GCC and MSVC compatibility.

Differential Revision: http://llvm-reviews.chandlerc.com/D1870

llvm-svn: 192308

show more ...

Delete CC_Default and use the target default CC everywhere

Summary:
Makes functions with implicit calling convention compatible with
function types with a matching explicit calling convention. This

Delete CC_Default and use the target default CC everywhere

Summary:
Makes functions with implicit calling convention compatible with
function types with a matching explicit calling convention. This fixes
things like calls to qsort(), which has an explicit __cdecl attribute on
the comparator in Windows headers.

Clang will now infer the calling convention from the declarator. There
are two cases when the CC must be adjusted during redeclaration:
1. When defining a non-inline static method.
2. When redeclaring a function with an implicit or mismatched
convention.

Fixes PR13457, and allows clang to compile CommandLine.cpp for the
Microsoft C++ ABI.

Excellent test cases provided by Alexander Zinenko!

Reviewers: rsmith

Differential Revision: http://llvm-reviews.chandlerc.com/D1231

llvm-svn: 189412

show more ...