Commit Graph

3164 Commits

Author SHA1 Message Date
Fangrui Song d8c09b7bbc Revert D111509 "[clang] use getCommonSugar in an assortment of places"
This reverts commit d42122cd5d.

`clang++ gcc/libstdc++-v3/src/c++98/complex_io.cc` (all language modes) crashes.
Also see https://reviews.llvm.org/D111509#3777980
2022-09-08 17:09:18 -07:00
Matheus Izvekov d42122cd5d
[clang] use getCommonSugar in an assortment of places
For this patch, a simple search was performed for patterns where there are
two types (usually an LHS and an RHS) which are structurally the same, and there
is some result type which is resolved as either one of them (typically LHS for
consistency).

We change those cases to resolve as the common sugared type between those two,
utilizing the new infrastructure created for this purpose.

Depends on D111283

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

Differential Revision: https://reviews.llvm.org/D111509
2022-09-08 19:17:53 +02:00
Kazu Hirata b7a7aeee90 [clang] Qualify auto in range-based for loops (NFC) 2022-09-03 23:27:27 -07:00
Utkarsh Saxena e7eec38246 [clang] Skip re-building lambda expressions in parameters to consteval fns.
As discussed in this [comment](https://github.com/llvm/llvm-project/issues/56183#issuecomment-1224331699),
we end up building the lambda twice: once while parsing the function calls and then again while handling the immediate invocation.

This happens specially during removing nested immediate invocation.
Eg: When we have another consteval function as the parameter along with this lambda expression. Eg: `foo(bar([]{}))`, `foo(bar(), []{})`

While removing such nested immediate invocations, we should not rebuild this lambda. (IIUC, rebuilding a lambda would always generate a new type which will never match the original type from parsing)

Fixes: https://github.com/llvm/llvm-project/issues/56183
Fixes: https://github.com/llvm/llvm-project/issues/51695
Fixes: https://github.com/llvm/llvm-project/issues/50455
Fixes: https://github.com/llvm/llvm-project/issues/54872
Fixes: https://github.com/llvm/llvm-project/issues/54587

Differential Revision: https://reviews.llvm.org/D132945
2022-09-02 12:30:52 +02:00
Utkarsh Saxena 4a043c6376 PotentiallyEvaluatedContext in a ImmediateFunctionContext.
Body of `consteval` should be in an `ImmediateFunctionContext` instead of `ConstantEvaluated`.
PotentiallyEvaluated expressions in Immediate functions are in a `ImmediateFunctionContext` as well.

Fixes https://github.com/llvm/llvm-project/issues/51182
Original divergence: https://godbolt.org/z/vadGT5j6f

Differential Revision: https://reviews.llvm.org/D132659
2022-08-26 10:30:10 +02:00
Akira Hatanaka 5d794552bc [Sema][ObjC] Don't warn about implicitly-retained self in an unevaluated
context
2022-08-22 12:16:37 -07:00
Erich Keane 95d94a6775 Revert "Re-apply "Deferred Concept Instantiation Implementation"""
This reverts commit d483730d8c.

This allegedly breaks a significant part of facebooks internal build.
Reverting while we wait for them to provide a reproducer of this from
@wlei.
2022-08-19 12:47:34 -07:00
Utkarsh Saxena 0e0e8b6576 Do not evaluate dependent immediate invocations
We deferred the evaluation of dependent immediate invocations in https://reviews.llvm.org/D119375 until instantiation.
We should also not consider them referenced from a non-consteval context.

Fixes: https://github.com/llvm/llvm-project/issues/55601

```
template<typename T>
class Bar {
  consteval static T x() { return 5; }
 public:
  Bar() : a(x()) {}

 private:
  int a;
};

Bar<int> g();
```
Is now accepted by clang. Previously it errored with: `cannot take address of consteval function 'x' outside of an immediate invocation  Bar() : a(x()) {}`

Differential Revision: https://reviews.llvm.org/D132031
2022-08-18 10:30:40 +02:00
Erich Keane d483730d8c Re-apply "Deferred Concept Instantiation Implementation""
This reverts commit 258c3aee54.

This should fix the libc++ issue that caused the revert, by re-designing
slightly how we determined when we should evaluate the constraints.
Additionally, many of the other components to the original patch (the
NFC parts) were committed separately to shrink the size of this patch
for review.

Differential Revision: https://reviews.llvm.org/D126907
2022-08-17 06:24:40 -07:00
YingChi Long ccbc22cd89
[Sema] fix false -Wcomma being emitted from void returning functions
Fixes https://github.com/llvm/llvm-project/issues/57151

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D131892
2022-08-16 20:44:38 +08:00
David Truby 286d59ef6f [clang][AArch64][SVE] Add unary +/- operators for SVE types
This patch enables the unary promotion and negation operators on
SVE types.

Differential Revision: https://reviews.llvm.org/D130984
2022-08-10 10:32:43 +00:00
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
Corentin Jabot a1a71b7dc9 [Clang] Fix capture of values initialized by bitfields
This fixes a regression introduced in 127bf44

Differential Revision: https://reviews.llvm.org/D131202
2022-08-04 23:58:47 +02:00
Corentin Jabot 127bf44385 [Clang][C++20] Support capturing structured bindings in lambdas
This completes the implementation of P1091R3 and P1381R1.

This patch allow the capture of structured bindings
both for C++20+ and C++17, with extension/compat warning.

In addition, capturing an anonymous union member,
a bitfield, or a structured binding thereof now has a
better diagnostic.

We only support structured bindings - as opposed to other kinds
of structured statements/blocks. We still emit an error for those.

In addition, support for structured bindings capture is entirely disabled in
OpenMP mode as this needs more investigation - a specific diagnostic indicate the feature is not yet supported there.

Note that the rest of P1091R3 (static/thread_local structured bindings) was already implemented.

at the request of @shafik, i can confirm the correct behavior of lldb wit this change.

Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/52720

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D122768
2022-08-04 10:12:53 +02:00
Corentin Jabot a274219600 Revert "[Clang][C++20] Support capturing structured bindings in lambdas"
This reverts commit 44f2baa380.

Breaks self builds and seems to have conformance issues.
2022-08-03 21:00:29 +02:00
Corentin Jabot 44f2baa380 [Clang][C++20] Support capturing structured bindings in lambdas
This completes the implementation of P1091R3 and P1381R1.

This patch allow the capture of structured bindings
both for C++20+ and C++17, with extension/compat warning.

In addition, capturing an anonymous union member,
a bitfield, or a structured binding thereof now has a
better diagnostic.

We only support structured bindings - as opposed to other kinds
of structured statements/blocks. We still emit an error for those.

In addition, support for structured bindings capture is entirely disabled in
OpenMP mode as this needs more investigation - a specific diagnostic indicate the feature is not yet supported there.

Note that the rest of P1091R3 (static/thread_local structured bindings) was already implemented.

at the request of @shafik, i can confirm the correct behavior of lldb wit this change.

Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/52720

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D122768
2022-08-03 20:00:01 +02:00
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
Corentin Jabot 0ba128f7c8 [Clang] De-deprecate volatile compound operations
As per P2327R1,

|=, &= and ^= are no longer deprecated in all languages mode.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D130421
2022-07-24 16:16:52 +02:00
Kazu Hirata 70257fab68 Use any_of (NFC) 2022-07-22 01:05:17 -07:00
Kazu Hirata 8b3ed1fa98 Remove redundant return statements (NFC)
Identified with readability-redundant-control-flow.
2022-07-17 15:37:46 -07:00
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
Erich Keane e71fd54719 [NFC] Move check for isEqualityOp to CheckFloatComparisons
So callers don't have to.  Also, fix a clang-format/use of auto fix in
CheckFloatComparisons.
2022-07-14 09:30:29 -07:00
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
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
Nathan James 54f57d3847
[clang] Add a fixit for warn-self-assign if LHS is a field with the same name as parameter on RHS
Add a fix-it for the common case of setters/constructors using parameters with the same name as fields
```lang=c++
struct A{
  int X;
  A(int X) { /*this->*/X = X; }
  void setX(int X) { /*this->*/X = X;
};
```

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D129202
2022-07-09 08:28:07 +01:00
Corentin Jabot a9a60f20e6 [Clang] Rename StringLiteral::isAscii() => isOrdinary() [NFC]
"Ascii" StringLiteral instances are actually narrow strings
that are UTF-8 encoded and do not have an encoding prefix.
(UTF8 StringLiteral are also UTF-8 encoded strings, but with
the u8 prefix.

To avoid possible confusion both with actuall ASCII strings,
and with future works extending the set of literal encodings
supported by clang, this rename StringLiteral::isAscii() to
isOrdinary(), matching C++ standard terminology.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D128762
2022-06-29 18:28:51 +02:00
Chuanqi Xu 9c04851cf5 [C++20] [Module] Support reachable definition initially/partially
This patch introduces a new kind of ModuleOwnershipKind as
ReachableWhenImported. This intended the status for reachable described
at: https://eel.is/c++draft/module.reach#3.

Note that this patch is not intended to support all semantics about
reachable semantics. For example, this patch didn't implement discarded
declarations in GMF. (https://eel.is/c++draft/module.global.frag#3).

This fixes: https://bugs.llvm.org/show_bug.cgi?id=52281 and
https://godbolt.org/z/81f3ocjfW.

Reviewed By: rsmith, iains

Differential Revision: https://reviews.llvm.org/D113545
2022-06-29 12:48:48 +08:00
Chuanqi Xu 7a541406b5 Revert "[C++20] [Modules] Implement Reachable initiallly"
This reverts commit a223ba0a69.

The previous commit don't contain additional information, which is bad.
2022-06-29 12:43:26 +08:00
Chuanqi Xu a223ba0a69 [C++20] [Modules] Implement Reachable initiallly 2022-06-29 12:32:31 +08:00
Kazu Hirata 80c12bdb3b [clang] Call *set::insert without checking membership first (NFC) 2022-06-18 10:41:26 -07:00
Maryam Moghadas 711a71d1ab PowerPC] Emit warning for incompatible vector types that are currently diagnosed with -fno-lax-vector-conversions
This patch is the last prerequisite to switch the default behaviour to -fno-lax-vector-conversions in the future.
The first path ;D124093; fixed the altivec implicit castings.

Reviewed By: amyk

Differential Revision: https://reviews.llvm.org/D126540
2022-06-16 20:28:34 -05:00
Shivam Gupta 48e1829874 [Diagnostics] Fix inconsistent shift-overflow warnings in C++20
This fixes https://github.com/llvm/llvm-project/issues/52873.
Don't warn in C++2A mode (and newer), as signed left shifts
always wrap and never overflow. Ref. -
https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1236r1.html.
2022-06-14 20:19:46 +05:30
David Truby b4f2f7bebd [clang][AArch64][SVE] Implicit conversions for vector-scalar operations
This patch allows the same implicit conversions for vector-scalar
operations in SVE that are allowed for NEON.

Depends on D126377

Reviewed By: c-rhodes

Differential Revision: https://reviews.llvm.org/D126380
2022-06-13 10:22:10 +00:00
David Truby 133a5f22d3 [clang][AArch64][SVE] Improve diagnostics for SVE operators
This patch corrects some diagnostics for the SVE sizeless vector
operators, including correctly diagnosing when the vectors are
different sizes.

Differential Revision: https://reviews.llvm.org/D126377
2022-06-07 15:35:36 +01:00
Evgeny Shulgin a4f8590247 [clang] Allow consteval functions in default arguments
We should not mark a function as "referenced" if we call it within a
ConstantExpr, because the expression will be folded to a value in LLVM
IR. To prevent emitting consteval function declarations, we should not "jump
over" a ConstantExpr when it is a top-level ParmVarDecl's subexpression.

Fixes https://github.com/llvm/llvm-project/issues/48230

Reviewed By: erichkeane, aaron.ballman, ChuanqiXu

Differenitial Revision: https://reviews.llvm.org/D119646
2022-06-07 10:54:37 +08:00
Kazu Hirata d93728978b [clang] Use llvm::is_contained (NFC) 2022-06-05 17:56:40 -07:00
Jamie Schmeiser efbf0136b4 Only issue warning for subtraction involving null pointers on live code paths
Summary:
Change the warning produced for subtraction from (or with) a null pointer
to only be produced when the code path is live.
https://github.com/llvm/llvm-project/issues/54570

Author: Jamie Schmeiser <schmeise@ca.ibm.com>
Reviewed By: anarazel (Andres Freund)
Differential Revision: https://reviews.llvm.org/D126816
2022-06-03 10:10:37 -04:00
Aaron Ballman 85750de685 Use the canonical type when matching a generic selection association
This ensures that a deduced type like __auto_type matches the correct
association instead of matching all associations.

This addresses a regression from e4a42c5b64

Fixes #55702
2022-05-26 07:42:13 -04:00
Aaron Ballman 47b8424a53 Correct the diagnostic behavior for unreachable _Generic associations in C++
New diagnostics were added for unreachable generic selection expression
associations in ca75ac5f04, but it did
not account for a difference in behavior between C and C++ regarding
lvalue to rvalue conversions. So we would issue diagnostics about a
selection being unreachable and then reach it. This corrects the
diagnostic behavior in that case.

Differential Revision: https://reviews.llvm.org/D125882
2022-05-18 12:45:38 -04:00
Aaron Ballman ca75ac5f04 Diagnose unreachable generic selection associations
The controlling expression of a _Generic selection expression undergoes
lvalue conversion, array conversion, and function conversion before
picking the association. This means that array types, function types,
and qualified types are all unreachable code if they're used as an
association. I've been caught by this twice in the past few months and
I figure that if a WG14 member can't seem to remember this rule, users
are also likely to struggle with it. So this adds an on-by-default
unreachable code diagnostic for generic selection expression
associations.

Note, we don't have to worry about function types as those are already
a constraint violation which generates an error.

Differential Revision: https://reviews.llvm.org/D125259
2022-05-10 11:15:56 -04:00
Aaron Ballman 199dfb4d0c Silence a false positive about an unevaluated expr w/side effects
If the operand to `sizeof` is an expression of VLA type, the operand is
still evaluated, so we should not issue a diagnostic about ignoring the
side effects in this case, as they're not actually ignored.

Fixes #48010
2022-05-05 12:12:30 -04:00
Aaron Ballman 94d36fdbd7 Fix a crash on invalid with _Generic expressions
We were failing to check if the controlling expression is dependent or
not when testing whether it has side effects. This would trigger an
assertion. Instead, if the controlling expression is dependent, we
suppress the check and diagnostic.

This fixes Issue 50227.
2022-05-04 12:41:56 -04:00
Aaron Ballman a9d68a5524 Generalize calls to ImplicitlyDefineFunction
In C++ and C2x, we would avoid calling ImplicitlyDefineFunction at all,
but in OpenCL mode we would still call the function and have it produce
an error diagnostic. Instead, we now have a helper function to
determine when implicit function definitions are allowed and we use
that to determine whether to call ImplicitlyDefineFunction so that the
behavior is more consistent across language modes.

This changes the diagnostic behavior from telling the users that an
implicit function declaration is not allowed in OpenCL to reporting use
of an unknown identifier and going through typo correction, as done in
C++ and C2x.
2022-04-30 10:03:51 -04:00
Richard Smith f6a5ab6c8c Use builtin recognition to detect std::move / std::forward.
Replaces some prior ad-hoc detection strategies and generally cleans up
a little. No functional change intended.
2022-04-21 14:21:07 -07:00
Richard Smith 72315d02c4 Treat `std::move`, `forward`, etc. as builtins.
This is extended to all `std::` functions that take a reference to a
value and return a reference (or pointer) to that same value: `move`,
`forward`, `move_if_noexcept`, `as_const`, `addressof`, and the
libstdc++-specific function `__addressof`.

We still require these functions to be declared before they can be used,
but don't instantiate their definitions unless their addresses are
taken. Instead, code generation, constant evaluation, and static
analysis are given direct knowledge of their effect.

This change aims to reduce various costs associated with these functions
-- per-instantiation memory costs, compile time and memory costs due to
creating out-of-line copies and inlining them, code size at -O0, and so
on -- so that they are not substantially more expensive than a cast.
Most of these improvements are very small, but I measured a 3% decrease
in -O0 object file size for a simple C++ source file using the standard
library after this change.

We now automatically infer the `const` and `nothrow` attributes on these
now-builtin functions, in particular meaning that we get a warning for
an unused call to one of these functions.

In C++20 onwards, we disallow taking the addresses of these functions,
per the C++20 "addressable function" rule. In earlier language modes, a
compatibility warning is produced but the address can still be taken.

The same infrastructure is extended to the existing MSVC builtin
`__GetExceptionInfo`, which is now only recognized in namespace `std`
like it always should have been.

This is a re-commit of
  fc30901096,
  a571f82a50,
  64c045e25b, and
  de6ddaeef3,
and reverts aa643f455a.
This change also includes a workaround for users using libc++ 3.1 and
earlier (!!), as apparently happens on AIX, where std::move sometimes
returns by value.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D123345

Revert "Fixup D123950 to address revert of D123345"

This reverts commit aa643f455a.
2022-04-20 17:58:31 -07:00
David Tenty 98d911e01f Revert "Treat `std::move`, `forward`, etc. as builtins."
This reverts commit b27430f9f4 as the
    parent https://reviews.llvm.org/D123345 breaks the AIX CI:

    https://lab.llvm.org/buildbot/#/builders/214/builds/819
2022-04-20 19:14:37 -04:00
Fangrui Song c79e6007ed Revert D119136 "[clang] Implement Change scope of lambda trailing-return-type" and its follow-up
This reverts commit 69dd89fdcb.
This reverts commit 04000c2f92.

The current states breaks libstdc++ usage (https://reviews.llvm.org/D119136#3455423).
The fixup has been reverted as it caused other valid code to be disallowed.
I think we should start from the clean state by reverting all relevant commits.
2022-04-20 10:57:12 -07:00
Dan Liew 3d612a930d [NFC] Avoid unnecessary duplication of code generating diagnostic.
The previous code unneccessarily duplicated the creation of a diagnostic
where the only difference was the `AssignmentAction` being passed.

rdar://88664722

Differential Revision: https://reviews.llvm.org/D124054
2022-04-20 10:50:21 -07:00
Fangrui Song 0f5dbfd29a Revert D123909 "[Clang] Use of decltype(capture) in parameter-declaration-clause"
This reverts commit daa6d7b250.

It breaks valid code like https://reviews.llvm.org/D123909#3461716
2022-04-20 10:32:41 -07:00