Commit Graph

689 Commits

Author SHA1 Message Date
Kazu Hirata abbe9c561d [clang] Use x.empty() instead of llvm::empty(x) (NFC)
I'm planning to deprecate and eventually remove llvm::empty.

Note that no use of llvm::empty requires the ability of llvm::empty to
determine the emptiness from begin/end only.
2022-09-18 11:07:50 -07:00
Kazu Hirata b7a7aeee90 [clang] Qualify auto in range-based for loops (NFC) 2022-09-03 23:27:27 -07:00
Denis Fatkulin 8837ef4d37
[clang] Apply FixIts to members declared via `using` in derived classes
FixIt don't switch to arrow in derrived members with `using`

Example code:
```
struct Bar {
  void foo();
};
struct Baz {
  using Bar::foo;
};
void test(Baz* ptr) {
  ptr.^
}

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D131088
2022-08-17 10:09:48 +02:00
Fangrui Song 3f18f7c007 [clang] LLVM_FALLTHROUGH => [[fallthrough]]. NFC
With C++17 there is no Clang pedantic warning or MSVC C5051.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D131346
2022-08-08 09:12:46 -07:00
Gabriel Ravier 5674a3c880 Fixed a number of typos
I went over the output of the following mess of a command:

(ulimit -m 2000000; ulimit -v 2000000; git ls-files -z |
 parallel --xargs -0 cat | aspell list --mode=none --ignore-case |
 grep -E '^[A-Za-z][a-z]*$' | sort | uniq -c | sort -n |
 grep -vE '.{25}' | aspell pipe -W3 | grep : | cut -d' ' -f2 | less)

and proceeded to spend a few days looking at it to find probable typos
and fixed a few hundred of them in all of the llvm project (note, the
ones I found are not anywhere near all of them, but it seems like a
good start).

Differential Revision: https://reviews.llvm.org/D130827
2022-08-01 13:13:18 -04:00
Matheus Izvekov 15f3cd6bfc
[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
2022-07-27 11:10:54 +02:00
Qwinci 3f73c57935 Argument name support for function pointer signature hints
Fixes https://github.com/clangd/clangd/issues/1068

Reviewed By: nridge

Differential Revision: https://reviews.llvm.org/D125120
2022-07-19 20:02:26 -04:00
Jonas Devlieghere 888673b6e3
Revert "[clang] Implement ElaboratedType sugaring for types written bare"
This reverts commit 7c51f02eff 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.
2022-07-14 21:17:48 -07:00
Matheus Izvekov 7c51f02eff
[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
2022-07-15 04:16:55 +02:00
Jonas Devlieghere 3968936b92
Revert "[clang] Implement ElaboratedType sugaring for types written bare"
This reverts commit bdc6974f92 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/
2022-07-13 09:20:30 -07:00
Kazu Hirata 53daa177f8 [clang, clang-tools-extra] Use has_value instead of hasValue (NFC) 2022-07-12 22:47:41 -07:00
Matheus Izvekov bdc6974f92
[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
2022-07-13 02:10:09 +02:00
Kazu Hirata 3b7c3a654c Revert "Don't use Optional::hasValue (NFC)"
This reverts commit aa8feeefd3.
2022-06-25 11:56:50 -07:00
Kazu Hirata aa8feeefd3 Don't use Optional::hasValue (NFC) 2022-06-25 11:55:57 -07:00
Kazu Hirata ca4af13e48 [clang] Don't use Optional::getValue (NFC) 2022-06-20 22:59:26 -07:00
Kazu Hirata 452db157c9 [clang] Don't use Optional::hasValue (NFC) 2022-06-20 10:51:34 -07:00
Furkan Usta 462def25ec
[clang] Use correct visibility parameters when following a Using declaration
Fixes https://github.com/clangd/clangd/issues/1137

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D127629
2022-06-15 15:52:59 +02:00
Alex Lorenz ee8524087c [libclang] add supporting for indexing/visiting C++ concepts
This commit builds upon recently added indexing support for C++ concepts
from https://reviews.llvm.org/D124441 by extending libclang to
support indexing and visiting concepts, constraints and requires
expressions as well.

Differential Revision: https://reviews.llvm.org/D126031
2022-05-24 10:02:53 -07:00
Jun Zhang 7fde4e2213
Add some helpers to better check Scope's kind. NFC
Signed-off-by: Jun Zhang <jun@junz.org>
2022-04-16 11:31:40 +08:00
Jan Svoboda 0b09b5d448 [clang][lex] NFC: Use FileEntryRef in PreprocessorLexer::getFileEntry()
This patch changes the return type of `PreprocessorLexer::getFileEntry()` so that its clients may stop using the deprecated APIs of `FileEntry`.

Reviewed By: bnbarham

Differential Revision: https://reviews.llvm.org/D123772
2022-04-15 15:16:17 +02:00
Benjamin Kramer 5d2ce7663b Use llvm::append_range instead of push_back loops where applicable. NFCI. 2022-03-18 01:25:34 +01:00
Simon Pilgrim ef865d16ec [clang] AddObjCKeyValueCompletions - use castAs<> instead of getAs<> to avoid dereference of nullptr
The pointers are always dereferenced, so assert the cast is correct instead of returning nullptr
2022-03-17 16:16:01 +00:00
Simon Pilgrim 1e64590041 [clang][sema] - remove CodeCompleter nullptr checks
All paths have already dereferenced the CodeCompleter pointer in the ResultBuilder constructor
2022-02-11 15:09:44 +00:00
Sam McCall 33c3ef2fbe [CodeCompletion][clangd] Clean __uglified parameter names in completion & hover
Underscore-uglified identifiers are used in standard library implementations to
guard against collisions with macros, and they hurt readability considerably.
(Consider `push_back(Tp_ &&__value)` vs `push_back(Tp value)`.
When we're describing an interface, the exact names of parameters are not
critical so we can drop these prefixes.

This patch adds a new PrintingPolicy flag that can applies this stripping
when recursively printing pieces of AST.
We set it in code completion/signature help, and in clangd's hover display.
All three features also do a bit of manual poking at names, so fix up those too.

Fixes https://github.com/clangd/clangd/issues/736

Differential Revision: https://reviews.llvm.org/D116387
2022-01-26 15:51:17 +01:00
Sam McCall 653b007dc1
[CodeComplete] fix nullptr crash in 612f5ed882 2022-01-21 23:18:23 +01:00
Kadir Cetinkaya 612f5ed882
[clang][CodeComplete] Perform approximate member search in bases
Differential Revision: https://reviews.llvm.org/D117037
2022-01-12 10:56:06 +01:00
Sam McCall bbf234b56a [CodeCompletion] Complete designators for fields in anonymous structs/unions
Fixes https://github.com/clangd/clangd/issues/836

Differential Revision: https://reviews.llvm.org/D116717
2022-01-11 00:58:49 +01:00
Kazu Hirata 40446663c7 [clang] Use true/false instead of 1/0 (NFC)
Identified with modernize-use-bool-literals.
2022-01-09 00:19:47 -08:00
Sam McCall 229c95ab66 [CodeCompletion] Signature help for aggregate initialization.
The "parameter list" is the list of fields which should be initialized.
We introduce a new OverloadCandidate kind for this.
It starts to become harder for CC consumers to handle all the cases for
params, so I added some extra APIs on OverloadCandidate to abstract them.

Includes some basic support for designated initializers.
The same aggregate signature is shown, the current arg jumps after the
one you just initialized. This follows C99 semantics for mixed
designated/positional initializers (which clang supports in C++ as an extension)
and is also a useful prompt for C++ as C++ designated initializers must be
in order.

Related bugs:
 - https://github.com/clangd/clangd/issues/965
 - https://github.com/clangd/clangd/issues/306

Differential Revision: https://reviews.llvm.org/D116326
2022-01-04 16:00:22 +01:00
Sam McCall 2a92efd0a2 [CodeComplete] drop unused Scope param. NFC 2022-01-04 12:36:27 +01:00
Aaron Ballman db77f7a074 Silence a "not all control paths return a value" warning; NFC 2022-01-03 14:20:09 -05:00
Sam McCall 92417eaf33 [CodeCompletion] Signature help for braced constructor calls
Implementation is based on the "expected type" as used for
designated-initializers in braced init lists. This means it can deduce the type
in some cases where it's not written:

  void foo(Widget);
  foo({ /*help here*/ });

Only basic constructor calls are in scope of this patch, excluded are:
 - aggregate initialization (no help is offered for aggregates)
 - initializer_list initialization (no help is offered for these constructors)

Fixes https://github.com/clangd/clangd/issues/306

Differential Revision: https://reviews.llvm.org/D116317
2022-01-03 20:14:59 +01:00
Sam McCall cd45e8c7bc [CodeCompletion] Signature help for template argument lists
Provide signature while typing template arguments: Foo< ^here >
Here the parameters are e.g. "typename x", and the result type is e.g.
"struct" (class template) or "int" (variable template) or "bool (std::string)"
(function template).

Multiple overloads are possible when a template name is used for several
overloaded function templates.

Fixes https://github.com/clangd/clangd/issues/299

Differential Revision: https://reviews.llvm.org/D116352
2022-01-03 16:28:16 +01:00
Kazu Hirata d677a7cb05 [clang] Remove redundant member initialization (NFC)
Identified with readability-redundant-member-init.
2022-01-02 10:20:23 -08:00
Kazu Hirata 2d303e6781 Remove redundant return and continue statements (NFC)
Identified with readability-redundant-control-flow.
2021-12-24 23:17:54 -08:00
Adam Czachorowski 55a79318c6 [clang][clangd] Improve signature help for variadic functions.
This covers both C-style variadic functions and template variadic w/
parameter packs.

Previously we would return no signatures when working with template
variadic functions once activeParameter reached the position of the
parameter pack (except when it was the only param, then we'd still
show it when no arguments were given). With this commit, we now show
signathure help correctly.

Additionally, this commit fixes the activeParameter value in LSP output
of clangd in the presence of variadic functions (both kinds). LSP does
not allow the activeParamter to be higher than the number of parameters
in the active signature. With "..." or parameter pack being just one
argument, for all but first argument passed to "..." we'd report
incorrect activeParameter value. Clients such as VSCode would then treat
it as 0, as suggested in the spec) and highlight the wrong parameter.

In the future, we should add support for per-signature activeParamter
value, which exists in LSP since 3.16.0. This is not part of this
commit.

Differential Revision: https://reviews.llvm.org/D111318
2021-11-18 15:50:47 +01:00
Christian Kandeler f7500a4ef7 [CodeCompletion] Generally consider header files without extension
Real-world use case: The Qt framework's headers have the same name
as the respective class defined in them, and Qt's traditional qmake
build tool uses -I (rather than -isystem) to pull them in.

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D112996
2021-11-10 08:22:48 +01:00
Richard Smith 7063b76b02 PR50644: Do not warn on a declaration of `operator"" _foo`.
Also do not warn on `#define _foo` or `#undef _foo`.

Only global scope names starting with _[a-z] are reserved, not the use
of such an identifier in any other context.
2021-10-06 15:13:05 -07:00
Nico Weber bde305baf6 [clang] Fix a few comment more typos to cycle bots 2021-09-20 19:42:49 -04:00
Sam McCall cab7c52acd [CodeCompletion] Provide placeholders for known attribute arguments
Completion now looks more like function/member completion:

  used
  alias(Aliasee)
  abi_tag(Tags...)

Differential Revision: https://reviews.llvm.org/D108109
2021-08-19 14:03:41 +02:00
Sam McCall a1ebae08f4 [CodeComplete] Only complete attributes that match the current LangOpts
Differential Revision: https://reviews.llvm.org/D108111
2021-08-19 13:35:07 +02:00
Sam McCall ece4e92085 [CodeComplete] Basic code completion for attribute names.
Only the bare name is completed, with no args.
For args to be useful we need arg names. These *are* in the tablegen but
not currently emitted in usable form, so left this as future work.

C++11, C2x, GNU, declspec, MS syntax is supported, with the appropriate
spellings of attributes suggested.
`#pragma clang attribute` is supported but not terribly useful as we
only reach completion if parens are balanced (i.e. the line is not truncated)

There's no filtering of which attributes might make sense in this
grammatical context (e.g. attached to a function). In code-completion context
this is hard to do, and will only work in few cases :-(

There's also no filtering by langopts: this is because currently the
only way of checking is to try to produce diagnostics, which requires a
valid ParsedAttr which is hard to get.
This should be fairly simple to fix but requires some tablegen changes
to expose the logic without the side-effect.

Differential Revision: https://reviews.llvm.org/D107696
2021-08-12 23:49:10 +02:00
Martin Storsjö e5c7c171e5 [clang] Rename StringRef _lower() method calls to _insensitive()
This is mostly a mechanical change, but a testcase that contains
parts of the StringRef class (clang/test/Analysis/llvm-conventions.cpp)
isn't touched.
2021-06-25 00:22:01 +03:00
Nathan Sidwell b2d0c16e91 [clang] p1099 using enum part 2
This implements the 'using enum maybe-qualified-enum-tag ;' part of
1099. It introduces a new 'UsingEnumDecl', subclassed from
'BaseUsingDecl'. Much of the diff is the boilerplate needed to get the
new class set up.

There is one case where we accept ill-formed, but I believe this is
merely an extended case of an existing bug, so consider it
orthogonal. AFAICT in class-scope the c++20 rule is that no 2 using
decls can bring in the same target decl ([namespace.udecl]/8). But we
already accept:

struct A { enum { a }; };
struct B : A { using A::a; };
struct C : B { using A::a;
using B::a; }; // same enumerator

this patch permits mixtures of 'using enum Bob;' and 'using Bob::member;' in the same way.

Differential Revision: https://reviews.llvm.org/D102241
2021-06-08 11:11:46 -07:00
Aaron Ballman 8edd3464af Add support for #elifdef and #elifndef
WG14 adopted N2645 and WG21 EWG has accepted P2334 in principle (still
subject to full EWG vote + CWG review + plenary vote), which add
support for #elifdef as shorthand for #elif defined and #elifndef as
shorthand for #elif !defined. This patch adds support for the new
preprocessor directives.
2021-05-27 08:57:47 -04:00
serge-sans-paille b83b23275b Introduce -Wreserved-identifier
Warn when a declaration uses an identifier that doesn't obey the reserved
identifier rule from C and/or C++.

Differential Revision: https://reviews.llvm.org/D93095
2021-05-04 11:19:01 +02:00
Jan Svoboda 6a72ed239c [clang] NFC: Fix range-based for loop warnings related to decl lookup 2021-04-19 18:31:31 +02:00
Sam McCall 128ce70eef [CodeCompletion] Avoid spurious signature help for init-list args
Somewhat surprisingly, signature help is emitted as a side-effect of
computing the expected type of a function argument.
The reason is that both actions require enumerating the possible
function signatures and running partial overload resolution, and doing
this twice would be wasteful and complicated.

Change #1: document this, it's subtle :-)

However, sometimes we need to compute the expected type without having
reached the code completion cursor yet - in particular to allow
completion of designators.
eb4ab3358c did this but introduced a
regression - it emits signature help in the wrong location as a side-effect.

Change #2: only emit signature help if the code completion cursor was reached.

Currently there is PP.isCodeCompletionReached(), but we can't use it
because it's set *after* running code completion.
It'd be nice to set this implicitly when the completion token is lexed,
but ConsumeCodeCompletionToken() makes this complicated.

Change #3: call cutOffParsing() *first* when seeing a completion token.

After this, the fact that the Sema::Produce*SignatureHelp() functions
are even more confusing, as they only sometimes do that.
I don't want to rename them in this patch as it's another large
mechanical change, but we should soon.

Change #4: prepare to rename ProduceSignatureHelp() to GuessArgumentType() etc.

Differential Revision: https://reviews.llvm.org/D98488
2021-03-16 12:46:40 +01:00
Sam McCall a92693dac4 [CodeCompletion] Don't track preferred types if code completion is disabled.
Some of this work isn't quite trivial.

(As requested in D96058)

Differential Revision: https://reviews.llvm.org/D98459
2021-03-16 12:16:10 +01:00
Kadir Cetinkaya f10137399a
[clang][CodeComplete] Ensure there are no crashes when completing with ParenListExprs as LHS
Differential Revision: https://reviews.llvm.org/D96950
2021-02-22 10:01:22 +01:00