[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -0,0 +1,16 @@ +// RUN: %clang_cc1 -fms-compatibility -fms-compatibility-version=19.33 -std=c++20 -verify=supported %s RIscRIpt wrote: Opened #74932. https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang] Fix '__cdecl' CC is not supported for this target (PR #74932)
https://github.com/RIscRIpt created
https://github.com/llvm/llvm-project/pull/74932
Fixes regression introduced in b3e6ff331925dde24a4707452d657da0fdf7f588
.---command stderr
| error: 'supported-warning' diagnostics seen but not expected:
| File
C:\buildbot\as-builder-1\x-armv7l\llvm-project\clang\test\SemaCXX\ms-constexpr-new.cpp
Line 7: '__cdecl' calling convention is not supported for this target
| 1 error generated.
`-
>From e16ec1411f7f813f7c1b60fd9671db116b083d02 Mon Sep 17 00:00:00 2001
From: Richard Dzenis
Date: Sat, 9 Dec 2023 15:44:54 +0200
Subject: [PATCH] [clang] Fix '__cdecl' CC is not supported for this target
Fixes regression introduced in b3e6ff331925dde24a4707452d657da0fdf7f588
.---command stderr
| error: 'supported-warning' diagnostics seen but not expected:
| File
C:\buildbot\as-builder-1\x-armv7l\llvm-project\clang\test\SemaCXX\ms-constexpr-new.cpp
Line 7: '__cdecl' calling convention is not supported for this target
| 1 error generated.
`-
---
clang/test/SemaCXX/ms-constexpr-new.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/test/SemaCXX/ms-constexpr-new.cpp
b/clang/test/SemaCXX/ms-constexpr-new.cpp
index 05ee5c5b4e154a..30567740b2ecbb 100644
--- a/clang/test/SemaCXX/ms-constexpr-new.cpp
+++ b/clang/test/SemaCXX/ms-constexpr-new.cpp
@@ -4,7 +4,7 @@
[[nodiscard]]
[[msvc::constexpr]] // unsupported-warning {{unknown attribute 'constexpr'
ignored}}
-inline void* __cdecl operator new(decltype(sizeof(void*)), void* p) noexcept {
return p; }
+inline void* operator new(decltype(sizeof(void*)), void* p) noexcept { return
p; }
namespace std {
constexpr int* construct_at(int* p, int v) {
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -0,0 +1,16 @@ +// RUN: %clang_cc1 -fms-compatibility -fms-compatibility-version=19.33 -std=c++20 -verify=supported %s RIscRIpt wrote: We can just remove `__cdecl` altogether. I put it there to replicate Microsoft's STL. MSVC accepts that test case without `__cdecl` too. Regarding other compiler error, it was fixed in 3ec6c72551846b8f4143c8c101a1a6203e85a2aa https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
RIscRIpt wrote: Suggested commit message: ``` Add support for 'msvc::constexpr' C++11 attribute This commit adds support for MSVC-specific C++11-style attribute `[[msvc::constexpr]]`, which was added in MSVC 14.33. The semantics of this attribute is enabled only under MSVC compatibility (`-fms-compatibility-version`) 14.33 and higher. Additionally, default value of `_MSC_VER` was raised to 1433. The current implementation misses support of: - `[[msvc::constexpr]]` constructors (see #72149); at the time of implementation such support required unreasonable amount of changes in Clang. - `[[msvc::constexpr]] return ::new` (constexpr placement new) from non-std namespace (see #74924). Relevant to: #57696 ``` https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
RIscRIpt wrote: I don't have write access, but I believe it is ready to be merged. https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
RIscRIpt wrote: Thank you! https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -2884,6 +2884,12 @@ def warn_cxx11_compat_constexpr_body_multiple_return :
Warning<
InGroup, DefaultIgnore;
def note_constexpr_body_previous_return : Note<
"previous return statement is here">;
+def err_ms_constexpr_not_distinct : Error<
+ "[[msvc::constexpr]] cannot be applied to a %select{constexpr|consteval}0
function %1">;
RIscRIpt wrote:
tl;dr afterall I would keep it as-is.
Sorry, I overestimated this possibility.
> attribute 'msvc::constexpr' cannot be applied to the virtual function %1
This could be replaced with existing diagnostic
```
def err_constexpr_virtual : Error<"virtual function cannot be constexpr">;
```
However, two other variants of this new diagnostic:
> attribute 'msvc::constexpr' cannot be applied to the constexpr function %1
> attribute 'msvc::constexpr' cannot be applied to the consteval function %1
Are not easily replaceable. The most similar diagnostic I was able to find was:
```
def err_invalid_decl_spec_combination : Error<
"cannot combine with previous '%0' declaration specifier">;
```
But, using this diagnostic, warnings are not consistent:
```
/home/richard/projects/llvm-project/clang/test/SemaCXX/ms-constexpr-invalid.cpp:10:3:
error: cannot combine with previous 'constexpr' declaration specifier
10 | [[msvc::constexpr]] constexpr void f1() {}
| ^~~~
```
`constexpr` comes after `[[msvc::constexpr]]`, but the message implies that
`constexpr` came first.
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -3657,6 +3657,21 @@ an error:
}];
}
+def MSConstexprDocs : Documentation {
+ let Category = DocCatStmt;
+ let Content = [{
+The ``[[msvc::constexpr]]`` attribute can be applied only to a function
+definition or a ``return`` statement. It does not impact function declarations.
+A ``[[msvc::constexpr]]`` function cannot be ``constexpr`` or ``consteval``.
+A ``[[msvc::constexpr]]`` function is treated as if it were a ``constexpr``
function
+if it is evaluated in a constant context of ``[[msvc::constexpr]] return``
statement.
+Otherwise, it is treated as a regular function.
+
+Semantics of this attribute is enabled only under MSVC compatibility
RIscRIpt wrote:
Adjusted manually.
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -5546,11 +5563,14 @@ static EvalStmtResult EvaluateStmt(StmtResult ,
EvalInfo ,
case Stmt::LabelStmtClass:
return EvaluateStmt(Result, Info, cast(S)->getSubStmt(), Case);
- case Stmt::AttributedStmtClass:
-// As a general principle, C++11 attributes can be ignored without
-// any semantic impact.
-return EvaluateStmt(Result, Info, cast(S)->getSubStmt(),
-Case);
+ case Stmt::AttributedStmtClass: {
+const auto *AS = cast(S);
+const auto *SS = AS->getSubStmt();
+MSConstexprContextRAII msConstexprContext(
RIscRIpt wrote:
Adjusted manually.
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -235,6 +235,7 @@ Non-comprehensive list of changes in this release except that it returns the size of a type ignoring tail padding. * ``__builtin_classify_type()`` now classifies ``_BitInt`` values as the return value ``18`` and vector types as return value ``19``, to match GCC 14's behavior. +* Since MSVC 19.33 added undocumented attribute ``[[msvc::constexpr]]``, this release adds the attribute as well. RIscRIpt wrote: Added back. https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
RIscRIpt wrote: > Also, please don't 'force-push', just push an additional commit to your > review. It erases history and makes reviewing it about 3x harder since > history/context gets lost. Sorry. I did this, because I am used to such workflow and reviewing [range-diff](https://github.com/llvm/llvm-project/compare/c700d21baf395aafbeea88778d13188650ed0c21..1af977ae49616ee00a64f50302f4cd88f9a51881); but to make it work one have to follow strict rule of pushing changes and rebased branch separately (which I failed to do previous time). https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
https://github.com/RIscRIpt updated
https://github.com/llvm/llvm-project/pull/71300
>From 3be36c6100801195f8f1f5167bdaa289bc8cb175 Mon Sep 17 00:00:00 2001
From: Richard Dzenis
Date: Thu, 20 Jul 2023 00:18:50 +0300
Subject: [PATCH 1/4] [clang-cl] Add support for [[msvc::constexpr]] C++11
attribute
Differential Revision: https://reviews.llvm.org/D134475
---
clang/include/clang/Basic/Attr.td | 8 +++
clang/include/clang/Basic/AttrDocs.td | 15 ++
.../clang/Basic/DiagnosticSemaKinds.td| 2 +
clang/include/clang/Basic/LangOptions.h | 1 +
clang/lib/AST/ExprConstant.cpp| 34 +---
clang/lib/Basic/Targets/OSTargets.cpp | 3 ++
clang/lib/Sema/SemaDecl.cpp | 4 +-
clang/lib/Sema/SemaDeclAttr.cpp | 25 +
clang/lib/Sema/SemaStmtAttr.cpp | 12 +
clang/test/AST/ms-constexpr.cpp | 28 ++
...a-attribute-supported-attributes-list.test | 1 +
clang/test/SemaCXX/ms-constexpr-invalid.cpp | 52 +++
clang/test/SemaCXX/ms-constexpr-new.cpp | 16 ++
clang/test/SemaCXX/ms-constexpr.cpp | 37 +
14 files changed, 231 insertions(+), 7 deletions(-)
create mode 100644 clang/test/AST/ms-constexpr.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr-invalid.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr-new.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr.cpp
diff --git a/clang/include/clang/Basic/Attr.td
b/clang/include/clang/Basic/Attr.td
index 121ed203829cec..b0a8ef10c500a7 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -3646,6 +3646,14 @@ def : MutualExclusions<[Owner, Pointer]>;
// Microsoft-related attributes
+def MSConstexpr : InheritableAttr {
+ let LangOpts = [MicrosoftExt];
+ let Spellings = [CXX11<"msvc", "constexpr">];
+ let Subjects = SubjectList<[Function, ReturnStmt], ErrorDiag,
+ "functions and return statements">;
+ let Documentation = [MSConstexprDocs];
+}
+
def MSNoVTable : InheritableAttr, TargetSpecificAttr {
let Spellings = [Declspec<"novtable">];
let Subjects = SubjectList<[CXXRecord]>;
diff --git a/clang/include/clang/Basic/AttrDocs.td
b/clang/include/clang/Basic/AttrDocs.td
index 88f7c65e6e847b..9dc6a909f07d09 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -3657,6 +3657,21 @@ an error:
}];
}
+def MSConstexprDocs : Documentation {
+ let Category = DocCatStmt;
+ let Content = [{
+The ``[[msvc::constexpr]]`` attribute can be applied only to a function
+definition or a ``return`` statement. It does not impact function declarations.
+A ``[[msvc::constexpr]]`` function cannot be ``constexpr`` or ``consteval``.
+A ``[[msvc::constexpr]]`` function is treated as if it were a ``constexpr``
function
+if it is evaluated in a constant context of ``[[msvc::constexpr]] return``
statement.
+Otherwise, it is treated as a regular function.
+
+Semantics of this attribute is enabled only under MSVC compatibility
+(``-fms-compatibility-version``) 19.33 and later.
+ }];
+}
+
def MSNoVTableDocs : Documentation {
let Category = DocCatDecl;
let Content = [{
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index ea08fa84d022cd..28d95ca9b13893 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2884,6 +2884,8 @@ def warn_cxx11_compat_constexpr_body_multiple_return :
Warning<
InGroup, DefaultIgnore;
def note_constexpr_body_previous_return : Note<
"previous return statement is here">;
+def err_ms_constexpr_cannot_be_applied : Error<
+ "attribute 'msvc::constexpr' cannot be applied to the
%select{constexpr|consteval|virtual}0 function %1">;
// C++20 function try blocks in constexpr
def ext_constexpr_function_try_block_cxx20 : ExtWarn<
diff --git a/clang/include/clang/Basic/LangOptions.h
b/clang/include/clang/Basic/LangOptions.h
index 2d167dd2bdf128..c4979b9a38c0cf 100644
--- a/clang/include/clang/Basic/LangOptions.h
+++ b/clang/include/clang/Basic/LangOptions.h
@@ -152,6 +152,7 @@ class LangOptions : public LangOptionsBase {
MSVC2019 = 1920,
MSVC2019_5 = 1925,
MSVC2019_8 = 1928,
+MSVC2022_3 = 1933,
};
enum SYCLMajorVersion {
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 986302e1fd225f..90cc0b84f0439c 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -641,6 +641,10 @@ namespace {
return false;
}
+/// Whether we're in a context where [[msvc::constexpr]] evaluation is
+/// permitted. See MSConstexprDocs for description of permitted contexts.
+bool CanEvalMSConstexpr = false;
+
private:
APValue (APValue::LValueBase Base, const void *Key, QualType T,
ScopeKind
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
https://github.com/RIscRIpt updated
https://github.com/llvm/llvm-project/pull/71300
>From 3be36c6100801195f8f1f5167bdaa289bc8cb175 Mon Sep 17 00:00:00 2001
From: Richard Dzenis
Date: Thu, 20 Jul 2023 00:18:50 +0300
Subject: [PATCH 1/2] [clang-cl] Add support for [[msvc::constexpr]] C++11
attribute
Differential Revision: https://reviews.llvm.org/D134475
---
clang/include/clang/Basic/Attr.td | 8 +++
clang/include/clang/Basic/AttrDocs.td | 15 ++
.../clang/Basic/DiagnosticSemaKinds.td| 2 +
clang/include/clang/Basic/LangOptions.h | 1 +
clang/lib/AST/ExprConstant.cpp| 34 +---
clang/lib/Basic/Targets/OSTargets.cpp | 3 ++
clang/lib/Sema/SemaDecl.cpp | 4 +-
clang/lib/Sema/SemaDeclAttr.cpp | 25 +
clang/lib/Sema/SemaStmtAttr.cpp | 12 +
clang/test/AST/ms-constexpr.cpp | 28 ++
...a-attribute-supported-attributes-list.test | 1 +
clang/test/SemaCXX/ms-constexpr-invalid.cpp | 52 +++
clang/test/SemaCXX/ms-constexpr-new.cpp | 16 ++
clang/test/SemaCXX/ms-constexpr.cpp | 37 +
14 files changed, 231 insertions(+), 7 deletions(-)
create mode 100644 clang/test/AST/ms-constexpr.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr-invalid.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr-new.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr.cpp
diff --git a/clang/include/clang/Basic/Attr.td
b/clang/include/clang/Basic/Attr.td
index 121ed203829cec..b0a8ef10c500a7 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -3646,6 +3646,14 @@ def : MutualExclusions<[Owner, Pointer]>;
// Microsoft-related attributes
+def MSConstexpr : InheritableAttr {
+ let LangOpts = [MicrosoftExt];
+ let Spellings = [CXX11<"msvc", "constexpr">];
+ let Subjects = SubjectList<[Function, ReturnStmt], ErrorDiag,
+ "functions and return statements">;
+ let Documentation = [MSConstexprDocs];
+}
+
def MSNoVTable : InheritableAttr, TargetSpecificAttr {
let Spellings = [Declspec<"novtable">];
let Subjects = SubjectList<[CXXRecord]>;
diff --git a/clang/include/clang/Basic/AttrDocs.td
b/clang/include/clang/Basic/AttrDocs.td
index 88f7c65e6e847b..9dc6a909f07d09 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -3657,6 +3657,21 @@ an error:
}];
}
+def MSConstexprDocs : Documentation {
+ let Category = DocCatStmt;
+ let Content = [{
+The ``[[msvc::constexpr]]`` attribute can be applied only to a function
+definition or a ``return`` statement. It does not impact function declarations.
+A ``[[msvc::constexpr]]`` function cannot be ``constexpr`` or ``consteval``.
+A ``[[msvc::constexpr]]`` function is treated as if it were a ``constexpr``
function
+if it is evaluated in a constant context of ``[[msvc::constexpr]] return``
statement.
+Otherwise, it is treated as a regular function.
+
+Semantics of this attribute is enabled only under MSVC compatibility
+(``-fms-compatibility-version``) 19.33 and later.
+ }];
+}
+
def MSNoVTableDocs : Documentation {
let Category = DocCatDecl;
let Content = [{
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index ea08fa84d022cd..28d95ca9b13893 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2884,6 +2884,8 @@ def warn_cxx11_compat_constexpr_body_multiple_return :
Warning<
InGroup, DefaultIgnore;
def note_constexpr_body_previous_return : Note<
"previous return statement is here">;
+def err_ms_constexpr_cannot_be_applied : Error<
+ "attribute 'msvc::constexpr' cannot be applied to the
%select{constexpr|consteval|virtual}0 function %1">;
// C++20 function try blocks in constexpr
def ext_constexpr_function_try_block_cxx20 : ExtWarn<
diff --git a/clang/include/clang/Basic/LangOptions.h
b/clang/include/clang/Basic/LangOptions.h
index 2d167dd2bdf128..c4979b9a38c0cf 100644
--- a/clang/include/clang/Basic/LangOptions.h
+++ b/clang/include/clang/Basic/LangOptions.h
@@ -152,6 +152,7 @@ class LangOptions : public LangOptionsBase {
MSVC2019 = 1920,
MSVC2019_5 = 1925,
MSVC2019_8 = 1928,
+MSVC2022_3 = 1933,
};
enum SYCLMajorVersion {
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 986302e1fd225f..90cc0b84f0439c 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -641,6 +641,10 @@ namespace {
return false;
}
+/// Whether we're in a context where [[msvc::constexpr]] evaluation is
+/// permitted. See MSConstexprDocs for description of permitted contexts.
+bool CanEvalMSConstexpr = false;
+
private:
APValue (APValue::LValueBase Base, const void *Key, QualType T,
ScopeKind
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
https://github.com/RIscRIpt edited https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -2861,8 +2861,8 @@ def warn_cxx17_compat_constexpr_local_var_no_init :
Warning<
"is incompatible with C++ standards before C++20">,
InGroup, DefaultIgnore;
def ext_constexpr_function_never_constant_expr : ExtWarn<
- "%select{constexpr|consteval}1 %select{function|constructor}0 never produces
a "
- "constant expression">, InGroup>,
DefaultError;
+ "%select{constexpr|consteval|[[msvc::constexpr]]}1
%select{function|constructor}0 "
RIscRIpt wrote:
As you raised concern about `[[` `]]`, and after I saw automatic diagnostic
when I changed Subjects to include ReturnStmt, I decided to use `constexpr`
variant in my cases. Let me know if we can do better here.
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -3612,6 +3612,22 @@ an error:
}];
}
+def MSConstexprDocs : Documentation {
+ let Category = DocCatStmt;
+ let Content = [{
+The ``[[msvc::constexpr]]`` attribute can be applied only to a function
+definition or a ``return`` statement. It does not impact function declarations.
+A ``[[msvc::constexpr]]`` function cannot be ``constexpr`` or ``consteval``.
+A ``[[msvc::constexpr]]`` function is treated in the same way as a
``constexpr``
RIscRIpt wrote:
Thanks, applied manually. Note, now there are two `if` words nearby. But
perhaps it's still better.
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -217,6 +217,8 @@ C23 Feature Support Non-comprehensive list of changes in this release - +- The default value of `_MSC_VER` was raised from 1920 to 1933. + MSVC 19.33 added undocumented attribute ``[[msvc::constexpr]]``. RIscRIpt wrote: Thanks, applied manually. https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -2884,6 +2884,12 @@ def warn_cxx11_compat_constexpr_body_multiple_return :
Warning<
InGroup, DefaultIgnore;
def note_constexpr_body_previous_return : Note<
"previous return statement is here">;
+def err_ms_constexpr_not_distinct : Error<
+ "[[msvc::constexpr]] cannot be applied to a %select{constexpr|consteval}0
function %1">;
+def err_ms_constexpr_virtual : Error<"virtual function cannot be
[[msvc::constexpr]]">;
+def warn_ms_constexpr_no_effect : Warning<
+ "[[msvc::constexpr]] has effect only on function definitions and return
statements">,
RIscRIpt wrote:
Tbh, I don't remember my reasoning. I can only say that MSVC at this moment
does not emit any warning/error: https://godbolt.org/z/YfMxYPqEx
Anyway, I changed subjects Stmt to ReturnStmt.
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -2884,6 +2884,12 @@ def warn_cxx11_compat_constexpr_body_multiple_return :
Warning<
InGroup, DefaultIgnore;
def note_constexpr_body_previous_return : Note<
"previous return statement is here">;
+def err_ms_constexpr_not_distinct : Error<
+ "[[msvc::constexpr]] cannot be applied to a %select{constexpr|consteval}0
function %1">;
RIscRIpt wrote:
You are right, changed.
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -2884,6 +2884,12 @@ def warn_cxx11_compat_constexpr_body_multiple_return :
Warning<
InGroup, DefaultIgnore;
def note_constexpr_body_previous_return : Note<
"previous return statement is here">;
+def err_ms_constexpr_not_distinct : Error<
+ "[[msvc::constexpr]] cannot be applied to a %select{constexpr|consteval}0
function %1">;
RIscRIpt wrote:
After the latest changes, this is the only `msvc::constexpr` specific attribute
left. What do you think if we use existing diagnostic messages with `constexpr`
variant instead of introducing a new diagnostic message?
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -2884,6 +2884,12 @@ def warn_cxx11_compat_constexpr_body_multiple_return :
Warning<
InGroup, DefaultIgnore;
def note_constexpr_body_previous_return : Note<
"previous return statement is here">;
+def err_ms_constexpr_not_distinct : Error<
+ "[[msvc::constexpr]] cannot be applied to a %select{constexpr|consteval}0
function %1">;
+def err_ms_constexpr_virtual : Error<"virtual function cannot be
[[msvc::constexpr]]">;
RIscRIpt wrote:
Done.
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
https://github.com/RIscRIpt edited https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
https://github.com/RIscRIpt commented: Addressed review comments; updated my tests to use changed diagnostic messages. Next I'll upload my branch rebased onto main. https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
https://github.com/RIscRIpt updated
https://github.com/llvm/llvm-project/pull/71300
>From d2b4e14210d7ac24e4a48407e8dc7dac9d97a549 Mon Sep 17 00:00:00 2001
From: Richard Dzenis
Date: Thu, 20 Jul 2023 00:18:50 +0300
Subject: [PATCH 1/2] [clang-cl] Add support for [[msvc::constexpr]] C++11
attribute
Differential Revision: https://reviews.llvm.org/D134475
---
clang/include/clang/Basic/Attr.td | 8 +++
clang/include/clang/Basic/AttrDocs.td | 15 ++
.../clang/Basic/DiagnosticSemaKinds.td| 2 +
clang/include/clang/Basic/LangOptions.h | 1 +
clang/lib/AST/ExprConstant.cpp| 34 +---
clang/lib/Basic/Targets/OSTargets.cpp | 3 ++
clang/lib/Sema/SemaDecl.cpp | 4 +-
clang/lib/Sema/SemaDeclAttr.cpp | 25 +
clang/lib/Sema/SemaStmtAttr.cpp | 12 +
clang/test/AST/ms-constexpr.cpp | 28 ++
...a-attribute-supported-attributes-list.test | 1 +
clang/test/SemaCXX/ms-constexpr-invalid.cpp | 52 +++
clang/test/SemaCXX/ms-constexpr-new.cpp | 16 ++
clang/test/SemaCXX/ms-constexpr.cpp | 37 +
14 files changed, 231 insertions(+), 7 deletions(-)
create mode 100644 clang/test/AST/ms-constexpr.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr-invalid.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr-new.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr.cpp
diff --git a/clang/include/clang/Basic/Attr.td
b/clang/include/clang/Basic/Attr.td
index 03ed6accf700c..21b18c79c93d4 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -3638,6 +3638,14 @@ def : MutualExclusions<[Owner, Pointer]>;
// Microsoft-related attributes
+def MSConstexpr : InheritableAttr {
+ let LangOpts = [MicrosoftExt];
+ let Spellings = [CXX11<"msvc", "constexpr">];
+ let Subjects = SubjectList<[Function, ReturnStmt], ErrorDiag,
+ "functions and return statements">;
+ let Documentation = [MSConstexprDocs];
+}
+
def MSNoVTable : InheritableAttr, TargetSpecificAttr {
let Spellings = [Declspec<"novtable">];
let Subjects = SubjectList<[CXXRecord]>;
diff --git a/clang/include/clang/Basic/AttrDocs.td
b/clang/include/clang/Basic/AttrDocs.td
index be74535e28d8a..c82d920aa9533 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -3612,6 +3612,21 @@ an error:
}];
}
+def MSConstexprDocs : Documentation {
+ let Category = DocCatStmt;
+ let Content = [{
+The ``[[msvc::constexpr]]`` attribute can be applied only to a function
+definition or a ``return`` statement. It does not impact function declarations.
+A ``[[msvc::constexpr]]`` function cannot be ``constexpr`` or ``consteval``.
+A ``[[msvc::constexpr]]`` function is treated as if it were a ``constexpr``
function
+if it is evaluated in a constant context of ``[[msvc::constexpr]] return``
statement.
+Otherwise, it is treated as a regular function.
+
+Semantics of this attribute is enabled only under MSVC compatibility
+(``-fms-compatibility-version``) 19.33 and later.
+ }];
+}
+
def MSNoVTableDocs : Documentation {
let Category = DocCatDecl;
let Content = [{
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 6894e22da34e0..629257915d83e 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2884,6 +2884,8 @@ def warn_cxx11_compat_constexpr_body_multiple_return :
Warning<
InGroup, DefaultIgnore;
def note_constexpr_body_previous_return : Note<
"previous return statement is here">;
+def err_ms_constexpr_cannot_be_applied : Error<
+ "attribute 'msvc::constexpr' cannot be applied to the
%select{constexpr|consteval|virtual}0 function %1">;
// C++20 function try blocks in constexpr
def ext_constexpr_function_try_block_cxx20 : ExtWarn<
diff --git a/clang/include/clang/Basic/LangOptions.h
b/clang/include/clang/Basic/LangOptions.h
index 2d167dd2bdf12..c4979b9a38c0c 100644
--- a/clang/include/clang/Basic/LangOptions.h
+++ b/clang/include/clang/Basic/LangOptions.h
@@ -152,6 +152,7 @@ class LangOptions : public LangOptionsBase {
MSVC2019 = 1920,
MSVC2019_5 = 1925,
MSVC2019_8 = 1928,
+MSVC2022_3 = 1933,
};
enum SYCLMajorVersion {
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 16697e5f076a8..668484c9ed9aa 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -641,6 +641,10 @@ namespace {
return false;
}
+/// Whether we're in a context where [[msvc::constexpr]] evaluation is
+/// permitted. See MSConstexprDocs for description of permitted contexts.
+bool CanEvalMSConstexpr = false;
+
private:
APValue (APValue::LValueBase Base, const void *Key, QualType T,
ScopeKind Scope);
@@
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
RIscRIpt wrote: Rebased onto main, resolved conflicts, re-run lit locally. Please let me know if I could speed-up review in any way. https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
https://github.com/RIscRIpt updated
https://github.com/llvm/llvm-project/pull/71300
>From 65c306e94e9b749ef0d38ef709ddb8b23dac987a Mon Sep 17 00:00:00 2001
From: Richard Dzenis
Date: Thu, 20 Jul 2023 00:18:50 +0300
Subject: [PATCH 1/2] [clang-cl] Add support for [[msvc::constexpr]] C++11
attribute
Differential Revision: https://reviews.llvm.org/D134475
---
clang/include/clang/Basic/Attr.td | 8 +++
clang/include/clang/Basic/AttrDocs.td | 16 ++
.../clang/Basic/DiagnosticSemaKinds.td| 10 +++-
clang/include/clang/Basic/LangOptions.h | 1 +
clang/lib/AST/ExprConstant.cpp| 34 +---
clang/lib/Basic/Targets/OSTargets.cpp | 3 ++
clang/lib/Sema/SemaDecl.cpp | 4 +-
clang/lib/Sema/SemaDeclAttr.cpp | 24 +
clang/lib/Sema/SemaDeclCXX.cpp| 5 +-
clang/lib/Sema/SemaStmtAttr.cpp | 16 ++
clang/test/AST/ms-constexpr.cpp | 28 ++
...a-attribute-supported-attributes-list.test | 1 +
clang/test/SemaCXX/ms-constexpr-invalid.cpp | 52 +++
clang/test/SemaCXX/ms-constexpr-new.cpp | 16 ++
clang/test/SemaCXX/ms-constexpr.cpp | 37 +
15 files changed, 245 insertions(+), 10 deletions(-)
create mode 100644 clang/test/AST/ms-constexpr.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr-invalid.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr-new.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr.cpp
diff --git a/clang/include/clang/Basic/Attr.td
b/clang/include/clang/Basic/Attr.td
index 03ed6accf700c4e6..08730e4dfd67feca 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -3638,6 +3638,14 @@ def : MutualExclusions<[Owner, Pointer]>;
// Microsoft-related attributes
+def MSConstexpr : InheritableAttr {
+ let LangOpts = [MicrosoftExt];
+ let Spellings = [CXX11<"msvc", "constexpr">];
+ let Subjects = SubjectList<[Function, Stmt], ErrorDiag,
+ "functions and statements">;
+ let Documentation = [MSConstexprDocs];
+}
+
def MSNoVTable : InheritableAttr, TargetSpecificAttr {
let Spellings = [Declspec<"novtable">];
let Subjects = SubjectList<[CXXRecord]>;
diff --git a/clang/include/clang/Basic/AttrDocs.td
b/clang/include/clang/Basic/AttrDocs.td
index be74535e28d8a60d..709a376bec9fbe95 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -3612,6 +3612,22 @@ an error:
}];
}
+def MSConstexprDocs : Documentation {
+ let Category = DocCatStmt;
+ let Content = [{
+The ``[[msvc::constexpr]]`` attribute can be applied only to a function
+definition or a ``return`` statement. It does not impact function declarations.
+A ``[[msvc::constexpr]]`` function cannot be ``constexpr`` or ``consteval``.
+A ``[[msvc::constexpr]]`` function is treated in the same way as a
``constexpr``
+function if it is evaluated in a constant context of
+``[[msvc::constexpr]] return`` statement.
+Otherwise, it is treated as a regular function.
+
+Semantics of this attribute is enabled only under MSVC compatibility
+(``-fms-compatibility-version``) 19.33 and later.
+ }];
+}
+
def MSNoVTableDocs : Documentation {
let Category = DocCatDecl;
let Content = [{
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 6894e22da34e0c74..43349cdfaea75c9a 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2861,8 +2861,8 @@ def warn_cxx17_compat_constexpr_local_var_no_init :
Warning<
"is incompatible with C++ standards before C++20">,
InGroup, DefaultIgnore;
def ext_constexpr_function_never_constant_expr : ExtWarn<
- "%select{constexpr|consteval}1 %select{function|constructor}0 never produces
a "
- "constant expression">, InGroup>,
DefaultError;
+ "%select{constexpr|consteval|[[msvc::constexpr]]}1
%select{function|constructor}0 "
+ "never produces a constant expression">,
InGroup>, DefaultError;
def err_attr_cond_never_constant_expr : Error<
"%0 attribute expression never produces a constant expression">;
def err_diagnose_if_invalid_diagnostic_type : Error<
@@ -2884,6 +2884,12 @@ def warn_cxx11_compat_constexpr_body_multiple_return :
Warning<
InGroup, DefaultIgnore;
def note_constexpr_body_previous_return : Note<
"previous return statement is here">;
+def err_ms_constexpr_not_distinct : Error<
+ "[[msvc::constexpr]] cannot be applied to a %select{constexpr|consteval}0
function %1">;
+def err_ms_constexpr_virtual : Error<"virtual function cannot be
[[msvc::constexpr]]">;
+def warn_ms_constexpr_no_effect : Warning<
+ "[[msvc::constexpr]] has effect only on function definitions and return
statements">,
+ InGroup;
// C++20 function try blocks in constexpr
def ext_constexpr_function_try_block_cxx20 : ExtWarn<
diff --git
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
RIscRIpt wrote: Oof, sorry, I forgot I should push new changes and rebased changes separately (otherwise "Compare" link does not make sense). If you had checkout `829f8098af96` locally, you can see the diff diff as follows: ``` git range-diff 829f8098af96~2..829f8098af96 7d8b1c0fae42~2..7d8b1c0fae42 ``` https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
https://github.com/RIscRIpt updated
https://github.com/llvm/llvm-project/pull/71300
>From 93be428cb8af34292305741a891ddffe362e9a20 Mon Sep 17 00:00:00 2001
From: Richard Dzenis
Date: Thu, 20 Jul 2023 00:18:50 +0300
Subject: [PATCH 1/2] [clang-cl] Add support for [[msvc::constexpr]] C++11
attribute
Differential Revision: https://reviews.llvm.org/D134475
---
clang/include/clang/Basic/Attr.td | 8 +++
clang/include/clang/Basic/AttrDocs.td | 16 ++
.../clang/Basic/DiagnosticSemaKinds.td| 10 +++-
clang/include/clang/Basic/LangOptions.h | 1 +
clang/lib/AST/ExprConstant.cpp| 34 +---
clang/lib/Basic/Targets/OSTargets.cpp | 3 ++
clang/lib/Sema/SemaDecl.cpp | 4 +-
clang/lib/Sema/SemaDeclAttr.cpp | 24 +
clang/lib/Sema/SemaDeclCXX.cpp| 5 +-
clang/lib/Sema/SemaStmtAttr.cpp | 16 ++
clang/test/AST/ms-constexpr.cpp | 28 ++
...a-attribute-supported-attributes-list.test | 1 +
clang/test/SemaCXX/ms-constexpr-invalid.cpp | 52 +++
clang/test/SemaCXX/ms-constexpr-new.cpp | 16 ++
clang/test/SemaCXX/ms-constexpr.cpp | 37 +
15 files changed, 245 insertions(+), 10 deletions(-)
create mode 100644 clang/test/AST/ms-constexpr.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr-invalid.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr-new.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr.cpp
diff --git a/clang/include/clang/Basic/Attr.td
b/clang/include/clang/Basic/Attr.td
index 31434565becaec6..82395f36c10ec6e 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -3614,6 +3614,14 @@ def : MutualExclusions<[Owner, Pointer]>;
// Microsoft-related attributes
+def MSConstexpr : InheritableAttr {
+ let LangOpts = [MicrosoftExt];
+ let Spellings = [CXX11<"msvc", "constexpr">];
+ let Subjects = SubjectList<[Function, Stmt], ErrorDiag,
+ "functions and statements">;
+ let Documentation = [MSConstexprDocs];
+}
+
def MSNoVTable : InheritableAttr, TargetSpecificAttr {
let Spellings = [Declspec<"novtable">];
let Subjects = SubjectList<[CXXRecord]>;
diff --git a/clang/include/clang/Basic/AttrDocs.td
b/clang/include/clang/Basic/AttrDocs.td
index fa6f6acd0c30e88..3f6b64e4cf0c173 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -3612,6 +3612,22 @@ an error:
}];
}
+def MSConstexprDocs : Documentation {
+ let Category = DocCatStmt;
+ let Content = [{
+The ``[[msvc::constexpr]]`` attribute can be applied only to a function
+definition or a ``return`` statement. It does not impact function declarations.
+A ``[[msvc::constexpr]]`` function cannot be ``constexpr`` or ``consteval``.
+A ``[[msvc::constexpr]]`` function is treated in the same way as a
``constexpr``
+function if it is evaluated in a constant context of
+``[[msvc::constexpr]] return`` statement.
+Otherwise, it is treated as a regular function.
+
+Semantics of this attribute is enabled only under MSVC compatibility
+(``-fms-compatibility-version``) 19.33 and later.
+ }];
+}
+
def MSNoVTableDocs : Documentation {
let Category = DocCatDecl;
let Content = [{
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 4614324babb1c91..10b03096a5c9557 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2861,8 +2861,8 @@ def warn_cxx17_compat_constexpr_local_var_no_init :
Warning<
"is incompatible with C++ standards before C++20">,
InGroup, DefaultIgnore;
def ext_constexpr_function_never_constant_expr : ExtWarn<
- "%select{constexpr|consteval}1 %select{function|constructor}0 never produces
a "
- "constant expression">, InGroup>,
DefaultError;
+ "%select{constexpr|consteval|[[msvc::constexpr]]}1
%select{function|constructor}0 "
+ "never produces a constant expression">,
InGroup>, DefaultError;
def err_attr_cond_never_constant_expr : Error<
"%0 attribute expression never produces a constant expression">;
def err_diagnose_if_invalid_diagnostic_type : Error<
@@ -2884,6 +2884,12 @@ def warn_cxx11_compat_constexpr_body_multiple_return :
Warning<
InGroup, DefaultIgnore;
def note_constexpr_body_previous_return : Note<
"previous return statement is here">;
+def err_ms_constexpr_not_distinct : Error<
+ "[[msvc::constexpr]] cannot be applied to a %select{constexpr|consteval}0
function %1">;
+def err_ms_constexpr_virtual : Error<"virtual function cannot be
[[msvc::constexpr]]">;
+def warn_ms_constexpr_no_effect : Warning<
+ "[[msvc::constexpr]] has effect only on function definitions and return
statements">,
+ InGroup;
// C++20 function try blocks in constexpr
def ext_constexpr_function_try_block_cxx20 : ExtWarn<
diff --git
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -0,0 +1,37 @@
+// RUN: %clang_cc1 -fms-compatibility -fms-compatibility-version=19.33
-std=c++20 -verify %s
+// expected-no-diagnostics
+
+[[msvc::constexpr]] int log2(int x) { [[msvc::constexpr]] return x > 1 ? 1 +
log2(x / 2) : 0; }
+constexpr bool test_log2() { [[msvc::constexpr]] return log2(32) == 5; }
+static_assert(test_log2());
+
+[[msvc::constexpr]] int get_value(int x)
+{
+ switch (x)
+ {
+case 42: return 1337;
+default:
+ if (x < 0) [[msvc::constexpr]] return log2(-x);
+ else return x;
+ }
+}
+
+constexpr bool test_complex_expr() {
+ [[msvc::constexpr]] return get_value(get_value(42) - 1337 + get_value(-32) -
5 + (get_value(1) ? get_value(0) : get_value(2))) == get_value(0);
+}
+static_assert(test_complex_expr());
+
+constexpr bool get_constexpr_true() { return true; }
+[[msvc::constexpr]] bool get_msconstexpr_true() { return get_constexpr_true();
}
+constexpr bool test_get_msconstexpr_true() { [[msvc::constexpr]] return
get_msconstexpr_true(); }
+static_assert(test_get_msconstexpr_true());
+
+/*
+// TODO: Add support for [[msvc::constexpr]] constructor
RIscRIpt wrote:
I thought I could send send all comments at once (like in GitLab or
Phabricator), but unfortunately not. I was in process of rebasing and
re-running lit tests.
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -0,0 +1,37 @@
+// RUN: %clang_cc1 -fms-compatibility -fms-compatibility-version=19.33
-std=c++20 -verify %s
+// expected-no-diagnostics
+
+[[msvc::constexpr]] int log2(int x) { [[msvc::constexpr]] return x > 1 ? 1 +
log2(x / 2) : 0; }
+constexpr bool test_log2() { [[msvc::constexpr]] return log2(32) == 5; }
+static_assert(test_log2());
+
+[[msvc::constexpr]] int get_value(int x)
+{
+ switch (x)
+ {
+case 42: return 1337;
+default:
+ if (x < 0) [[msvc::constexpr]] return log2(-x);
+ else return x;
+ }
+}
+
+constexpr bool test_complex_expr() {
+ [[msvc::constexpr]] return get_value(get_value(42) - 1337 + get_value(-32) -
5 + (get_value(1) ? get_value(0) : get_value(2))) == get_value(0);
+}
+static_assert(test_complex_expr());
+
+constexpr bool get_constexpr_true() { return true; }
+[[msvc::constexpr]] bool get_msconstexpr_true() { return get_constexpr_true();
}
+constexpr bool test_get_msconstexpr_true() { [[msvc::constexpr]] return
get_msconstexpr_true(); }
+static_assert(test_get_msconstexpr_true());
+
+/*
+// TODO: Add support for [[msvc::constexpr]] constructor
RIscRIpt wrote:
Created a follow-up #72149.
> However, i think we should enable the test, and record the diagnostic to
> ensure we show it is invalid for now (along with better showing the TODO).
I hope I understood you correctly: I enabled the test, and added `expected-*`
comments alongside with `TODO` mentioning 72149.
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -7337,6 +7337,27 @@ static void handleDeclspecThreadAttr(Sema , Decl *D,
const ParsedAttr ) {
D->addAttr(::new (S.Context) ThreadAttr(S.Context, AL));
}
+static void handleMSConstexprAttr(Sema , Decl *D, const ParsedAttr ) {
+ if (!S.getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2022_3)) {
+S.Diag(AL.getLoc(), diag::warn_unknown_attribute_ignored)
+<< AL << AL.getRange();
+return;
+ }
+ auto *FD = cast(D);
+ if (FD->isConstexprSpecified() || FD->isConsteval()) {
+S.Diag(AL.getLoc(), diag::err_ms_constexpr_not_distinct)
+<< FD->isConsteval() << FD;
+return;
+ }
+ if (auto *MD = dyn_cast(FD)) {
RIscRIpt wrote:
Prior to C++20 `constexpr` functions were not allowed to be `virtual`
[cppreference](https://en.cppreference.com/w/cpp/language/constexpr).
I know this is an attribute, but this matches MSVC behavior:
https://godbolt.org/z/snn6c1EW7
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
@@ -0,0 +1,37 @@
+// RUN: %clang_cc1 -fms-compatibility -fms-compatibility-version=19.33
-std=c++20 -verify %s
+// expected-no-diagnostics
+
+[[msvc::constexpr]] int log2(int x) { [[msvc::constexpr]] return x > 1 ? 1 +
log2(x / 2) : 0; }
+constexpr bool test_log2() { [[msvc::constexpr]] return log2(32) == 5; }
+static_assert(test_log2());
+
+[[msvc::constexpr]] int get_value(int x)
+{
+ switch (x)
+ {
+case 42: return 1337;
+default:
+ if (x < 0) [[msvc::constexpr]] return log2(-x);
+ else return x;
+ }
+}
+
+constexpr bool test_complex_expr() {
+ [[msvc::constexpr]] return get_value(get_value(42) - 1337 + get_value(-32) -
5 + (get_value(1) ? get_value(0) : get_value(2))) == get_value(0);
+}
+static_assert(test_complex_expr());
+
+constexpr bool get_constexpr_true() { return true; }
+[[msvc::constexpr]] bool get_msconstexpr_true() { return get_constexpr_true();
}
+constexpr bool test_get_msconstexpr_true() { [[msvc::constexpr]] return
get_msconstexpr_true(); }
+static_assert(test_get_msconstexpr_true());
+
+/*
+// TODO: Add support for [[msvc::constexpr]] constructor
RIscRIpt wrote:
Note: this is a long-term TODO, which is quite difficult to implement with
reasonably small changes.
Please let me know, how you typically deal with such cases.
---
Redacted comment from https://reviews.llvm.org/D134475#4288759:
Regarding on absolute matching MSVC implementation, I am not sure we will be
able to achieve it with reasonable changes. I am skeptical, because I
discovered the following test case: (which you see in the code).
It's a valid code for MSVC; nothing special https://godbolt.org/z/znnaonEhM
However supporting this code seems to be difficult in Clang:
`S2` fails checks of "literal type" in this callstack:
1.
[clang::CXXRecordDecl::isLiteral](https://github.com/llvm/llvm-project/blob/d27897ade53ab6f983e442f24880260eed26238a/clang/include/clang/AST/DeclCXX.h#L1425-L1451)
2.
[clang::Type::isLiteralType](https://github.com/llvm/llvm-project/blob/d27897ade53ab6f983e442f24880260eed26238a/clang/lib/AST/Type.cpp#L2795)
3.
[CheckLiteralType](https://github.com/llvm/llvm-project/blob/d27897ade53ab6f983e442f24880260eed26238a/clang/lib/AST/ExprConstant.cpp#L2392-L2397)
We have information about `CanEvalMSConstexpr` only in `CheckLiteralType`. So,
currently, I don't see how we can reasonably check whether `S2` is a valid
literal type in context of `[[msvc::constexpr]]`. Two obvious ugly solutions
are:
1. Copy all checks from `clang::CXXRecordDecl::isLiteral` to `CheckLiteralType`
- two places shall be maintained.
2. Propagate `CanEvalMSConstexpr` down to `clang::CXXRecordDecl::isLiteral`. We
could add bool args for both `clang::CXXRecordDecl::isLiteral` and
`clang::Type::isLiteralType`. But I don't think it's reasonable for supporting
rare vendor-specific attribute. Or is it?
I'll try to dive into this problem again, when I start addressing another round
of review comments.
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
https://github.com/RIscRIpt edited https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
RIscRIpt wrote: Discussion initiated by @AaronBallman of one of important design decisions, which was forgotten (?): > @AaronBallman: > It's a good question as to whether we want to support that only when passing > `-fms-extensions` or not (it seems like a generally useful attribute); we > don't do the same for GNU attributes, but maybe we don't want to follow that > pattern? This will be the first attribute we add with the `msvc` vendor > namespace. > @RIscRIpt: > IMO, this attribute is a clearly Microsoft's extension, thus it should be > available only when `-fms-extensions` are enabled. Note: in the current implementation I enable `[[msvc::constexpr]]` only under `-fms-compatibility -fms-compatibility-version=19.33`, (MSVC 19.33), where this attribute has first appeared. https://github.com/llvm/llvm-project/pull/71300 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
RIscRIpt wrote:
Initially I replicated semantics of `[[msvc::constexpr]]` from MSVC, so that it
was possible to use it the same way as in MSVC, even `[[msvc::constexpr]]
return ::new` from non-std namespace. E.g. https://godbolt.org/z/7eKh5Envz
```cpp
// RUN: %clang_cc1 -fms-compatibility -fms-compatibility-version=19.33
-std=c++20 -ast-dump %s | FileCheck %s
// CHECK: used operator new
// CHECK: MSConstexprAttr 0x{{[0-9a-f]+}}
[[nodiscard]] [[msvc::constexpr]] inline void* __cdecl operator
new(decltype(sizeof(void*)), void* p) noexcept { return p; }
// CHECK: used constexpr construct_at
// CHECK: AttributedStmt 0x{{[0-9a-f]+}}
// CHECK-NEXT: MSConstexprAttr 0x{{[0-9a-f]+}}
// CHECK-NEXT: ReturnStmt 0x{{[0-9a-f]+}}
constexpr int* construct_at(int* p, int v) { [[msvc::constexpr]] return ::new
(p) int(v); }
constexpr bool check_construct_at() { int x; return *construct_at(, 42) ==
42; }
static_assert(check_construct_at());
```
However @rsmith raised a concern over changes in
`PointerExprEvaluator::VisitCXXNewExpr`:
```diff
bool IsNothrow = false;
bool IsPlacement = false;
+ bool IsMSConstexpr = Info.CurrentCall->CanEvalMSConstexpr &&
+ OperatorNew->hasAttr();
if (OperatorNew->isReservedGlobalPlacementOperator() &&
- Info.CurrentCall->isStdFunction() && !E->isArray()) {
+ (Info.CurrentCall->isStdFunction() || IsMSConstexpr) && !E->isArray()) {
```
> Do we really need this change? Was our existing check of whether the caller
> is in namespace std not sufficient for MS' standard library? I'd strongly
> prefer not to have a documented, user-visible attribute that gives permission
> to use placement new directly.
If I could choose, I would opt to fully replicate the behavior of MSVC.
However, I also acknowledge the concerns that have been raised.
@AaronBallman, @erichkeane, any comments?
https://github.com/llvm/llvm-project/pull/71300
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[clang] [clang-cl] Add support for [[msvc::constexpr]] C++11 attribute (PR #71300)
https://github.com/RIscRIpt created
https://github.com/llvm/llvm-project/pull/71300
As per agreement with @AaronBallman and @erichkeane, I am re-opening this patch
here.
The current version of the patch has undergone numerous revisions before it
became the version I am sending to GitHub.
Below you can find a summary of the history of changes.
The full history of all comments (excluding code-inline comments) is available
in this file:
[msvc-constexpr-D134475-comments.md](https://github.com/llvm/llvm-project/files/13257930/msvc-constexpr-D134475-comments.md)
---
Initially I submitted this patch to make `[[msvc::constexpr]]` visible in the
AST, with no semantics, and no tests at all. @AaronBallman has told me that you
typically don't accept such patches, so I started figuring out semantics of
`[[msvc::constexpr]]`.
At first I tried to kind of reverse-engineer it myself, I made several
observations, some of them were incorrect.
Later, @cpplearner noted:
> It appears that `[[msvc::constexpr]]` does not make a function `constexpr`,
> but if `[[msvc::constexpr]]` is used in a function definition and in a call
> to that function, then the annotated function call can be evaluated during
> constant evaluation: https://godbolt.org/z/3MPTsz6Yn
>
> Apparently this is used to implement `constexpr std::construct_at`, which
> needs to call placement operator new, but the latter is not `constexpr`.
Additionally I asked MSVC team to comment about `[[msvc::constexpr]]`. Cody
Miller from Microsoft has shared semantics of `[[msvc::constexpr]]`
[here](https://developercommunity.visualstudio.com/t/msvc::constexpr-specification/10259132).
Further testing and experiments revealed that, unfortunately not all of his
points were correct.
After some trials and errors, I came up with the following definition of
semantics for `[[msvc::constexpr]]`
The `[[msvc::constexpr]]` attribute can be applied only to a function
definition or a `return` statement.
It does not impact function declarations.
A `[[msvc::constexpr]]` function cannot be `constexpr` or `consteval`.
A `[[msvc::constexpr]]` function is treated in the same way as a
`constexpr` function
if it is evaluated in a constant context of `[[msvc::constexpr]] return`
statement.
Otherwise, it is treated as a regular function.
This doc-note was added to `MSConstexprDocs`.
As per this definition, we need to be able to track whether current invocation
of `[[msvc::constexpr]]` function comes from `[[msvc::constexpr]] return`
statement, which in turn comes from a constant evaluation context (i.e. a
`constexpr` function).
Thus I went with the approach, which I saw being used in some other cases: a
RAII helper (`MSConstexprContextRAII`), and a `bool` flag in `CallStackFrame`.
>From d27897ade53ab6f983e442f24880260eed26238a Mon Sep 17 00:00:00 2001
From: Richard Dzenis
Date: Thu, 20 Jul 2023 00:18:50 +0300
Subject: [PATCH 1/2] [clang-cl] Add support for [[msvc::constexpr]] C++11
attribute
Differential Revision: https://reviews.llvm.org/D134475
---
clang/include/clang/Basic/Attr.td | 8 +++
clang/include/clang/Basic/AttrDocs.td | 16 ++
.../clang/Basic/DiagnosticSemaKinds.td| 10 +++-
clang/include/clang/Basic/LangOptions.h | 1 +
clang/lib/AST/ExprConstant.cpp| 34 +---
clang/lib/Basic/Targets/OSTargets.cpp | 3 ++
clang/lib/Sema/SemaDecl.cpp | 4 +-
clang/lib/Sema/SemaDeclAttr.cpp | 24 +
clang/lib/Sema/SemaDeclCXX.cpp| 5 +-
clang/lib/Sema/SemaStmtAttr.cpp | 16 ++
clang/test/AST/ms-constexpr.cpp | 28 ++
...a-attribute-supported-attributes-list.test | 1 +
clang/test/SemaCXX/ms-constexpr-invalid.cpp | 52 +++
clang/test/SemaCXX/ms-constexpr-new.cpp | 16 ++
clang/test/SemaCXX/ms-constexpr.cpp | 37 +
15 files changed, 245 insertions(+), 10 deletions(-)
create mode 100644 clang/test/AST/ms-constexpr.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr-invalid.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr-new.cpp
create mode 100644 clang/test/SemaCXX/ms-constexpr.cpp
diff --git a/clang/include/clang/Basic/Attr.td
b/clang/include/clang/Basic/Attr.td
index 60b54c155e5..771ac5575e25d8c 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -3602,6 +3602,14 @@ def : MutualExclusions<[Owner, Pointer]>;
// Microsoft-related attributes
+def MSConstexpr : InheritableAttr {
+ let LangOpts = [MicrosoftExt];
+ let Spellings = [CXX11<"msvc", "constexpr">];
+ let Subjects = SubjectList<[Function, Stmt], ErrorDiag,
+ "functions and statements">;
+ let Documentation = [MSConstexprDocs];
+}
+
def MSNoVTable : InheritableAttr, TargetSpecificAttr {
let Spellings = [Declspec<"novtable">];
let Subjects = SubjectList<[CXXRecord]>;
