[libcxx-commits] [libcxx] [libc++] [test] Fix MSVC warnings (PR #93257)
Stephan T. Lavavej via libcxx-commits
libcxx-commits at lists.llvm.org
Thu May 23 17:09:59 PDT 2024
https://github.com/StephanTLavavej created https://github.com/llvm/llvm-project/pull/93257
Found while running libc++'s tests with MSVC's STL.
* Avoid MSVC warning C5101: use of preprocessor directive in function-like macro argument list is undefined behavior.
+ We can easily make this portable by extracting `constexpr bool is_newlib`.
+ Followup to #73440.
+ See #73598.
+ See #73836.
* Avoid MSVC warning C4267: 'return': conversion from 'size_t' to 'int', possible loss of data.
+ This warning is valid, but harmless for the test, so `static_cast<int>` will avoid it.
* Avoid MSVC warning C4146: unary minus operator applied to unsigned type, result still unsigned.
+ This warning is also valid (the scenario is sometimes intentional, but surprising enough that it's worth warning about). This is a C++17 test, so we can easily avoid it by testing `is_signed_v` at compile-time before testing `m < 0` and `n < 0` at run-time.
* Silence MSVC warning C4310: cast truncates constant value.
+ These warnings are being emitted by `T(255)`. Disabling the warning is simpler than attempting to restructure the code.
+ Followup to #79791.
* MSVC no longer emits warning C4521: multiple copy constructors specified.
+ This warning was removed from the compiler, since at least 2021-12-09.
>From 05ef2eaef0caa46310e31e24cdf4e435df241213 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl at nuwen.net>
Date: Mon, 20 May 2024 13:35:21 -0700
Subject: [PATCH 1/5] Avoid MSVC warning C5101: use of preprocessor directive
in function-like macro argument list is undefined behavior.
Followup to LLVM-73440. See LLVM-73598 and LLVM-73836.
---
.../syserr.errcat.objects/generic_category.pass.cpp | 9 ++++++---
.../syserr.errcat.objects/system_category.pass.cpp | 9 ++++++---
2 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/generic_category.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/generic_category.pass.cpp
index d4bbde75ae882..f9e49d02b8860 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/generic_category.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/generic_category.pass.cpp
@@ -50,12 +50,15 @@ int main(int, char**)
// responds with an empty message, which we probably want to
// treat as a failure code otherwise, but we can detect that
// with the preprocessor.
+#if defined(_NEWLIB_VERSION)
+ [[maybe_unused]] constexpr bool is_newlib = true;
+#else
+ [[maybe_unused]] constexpr bool is_newlib = false;
+#endif
LIBCPP_ASSERT(msg.rfind("Error -1 occurred", 0) == 0 // AIX
|| msg.rfind("No error information", 0) == 0 // Musl
|| msg.rfind("Unknown error", 0) == 0 // Glibc
-#if defined(_NEWLIB_VERSION)
- || msg.empty()
-#endif
+ || (is_newlib && msg.empty())
);
assert(errno == E2BIG);
}
diff --git a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/system_category.pass.cpp b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/system_category.pass.cpp
index eefbddd27a7f5..a14d6cd6cb4fb 100644
--- a/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/system_category.pass.cpp
+++ b/libcxx/test/std/diagnostics/syserr/syserr.errcat/syserr.errcat.objects/system_category.pass.cpp
@@ -56,12 +56,15 @@ int main(int, char**) {
// responds with an empty message, which we probably want to
// treat as a failure code otherwise, but we can detect that
// with the preprocessor.
+#if defined(_NEWLIB_VERSION)
+ [[maybe_unused]] constexpr bool is_newlib = true;
+#else
+ [[maybe_unused]] constexpr bool is_newlib = false;
+#endif
LIBCPP_ASSERT(msg.rfind("Error -1 occurred", 0) == 0 // AIX
|| msg.rfind("No error information", 0) == 0 // Musl
|| msg.rfind("Unknown error", 0) == 0 // Glibc
-#if defined(_NEWLIB_VERSION)
- || msg.empty()
-#endif
+ || (is_newlib && msg.empty())
);
assert(errno == E2BIG);
}
>From 63140492222ac7022adf534b63c8cf2e42ce90cd Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl at nuwen.net>
Date: Mon, 20 May 2024 13:46:00 -0700
Subject: [PATCH 2/5] Avoid MSVC warning C4267: 'return': conversion from
'size_t' to 'int', possible loss of data.
---
.../views/views.span/span.cons/initializer_list.pass.cpp | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/libcxx/test/std/containers/views/views.span/span.cons/initializer_list.pass.cpp b/libcxx/test/std/containers/views/views.span/span.cons/initializer_list.pass.cpp
index 74a5094f61261..bc76e23fea3c0 100644
--- a/libcxx/test/std/containers/views/views.span/span.cons/initializer_list.pass.cpp
+++ b/libcxx/test/std/containers/views/views.span/span.cons/initializer_list.pass.cpp
@@ -93,9 +93,9 @@ constexpr bool test() {
// Test P2447R4 "Annex C examples"
-constexpr int three(std::span<void* const> sp) { return sp.size(); }
+constexpr int three(std::span<void* const> sp) { return static_cast<int>(sp.size()); }
-constexpr int four(std::span<const std::any> sp) { return sp.size(); }
+constexpr int four(std::span<const std::any> sp) { return static_cast<int>(sp.size()); }
bool test_P2447R4_annex_c_examples() {
// 1. Overload resolution is affected
>From db9ebe052b20e859cbe82e3ce5ecd27b86a6a6e1 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl at nuwen.net>
Date: Mon, 20 May 2024 14:40:41 -0700
Subject: [PATCH 3/5] Avoid MSVC warning C4146: unary minus operator applied to
unsigned type, result still unsigned.
---
.../numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
index 212804356a056..bf40b174b209c 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
@@ -57,10 +57,12 @@ T basic_gcd_(T m, T n) {
template <typename T>
T basic_gcd(T m, T n) {
using Tp = std::make_unsigned_t<T>;
- if (m < 0 && m != std::numeric_limits<T>::min())
- m = -m;
- if (n < 0 && n != std::numeric_limits<T>::min())
- n = -n;
+ if constexpr (std::is_signed_v<T>) {
+ if (m < 0 && m != std::numeric_limits<T>::min())
+ m = -m;
+ if (n < 0 && n != std::numeric_limits<T>::min())
+ n = -n;
+ }
return basic_gcd_(static_cast<Tp>(m), static_cast<Tp>(n));
}
>From baa373d4f3a52b85a3bdd676d2cba738bb62155d Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl at nuwen.net>
Date: Wed, 22 May 2024 23:09:58 -0700
Subject: [PATCH 4/5] Silence MSVC warning C4310: cast truncates constant
value.
These warnings are being emitted by `T(255)`.
Followup to LLVM-79791.
---
.../std/atomics/atomics.ref/compare_exchange_strong.pass.cpp | 3 +++
.../std/atomics/atomics.ref/compare_exchange_weak.pass.cpp | 3 +++
libcxx/test/std/atomics/atomics.ref/wait.pass.cpp | 3 +++
3 files changed, 9 insertions(+)
diff --git a/libcxx/test/std/atomics/atomics.ref/compare_exchange_strong.pass.cpp b/libcxx/test/std/atomics/atomics.ref/compare_exchange_strong.pass.cpp
index 72b2f444c476c..90aa5ea5b6df4 100644
--- a/libcxx/test/std/atomics/atomics.ref/compare_exchange_strong.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.ref/compare_exchange_strong.pass.cpp
@@ -9,6 +9,9 @@
// XFAIL: !has-64-bit-atomics
// XFAIL: !has-1024-bit-atomics
+// MSVC warning C4310: cast truncates constant value
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4310
+
// bool compare_exchange_strong(T&, T, memory_order, memory_order) const noexcept;
// bool compare_exchange_strong(T&, T, memory_order = memory_order::seq_cst) const noexcept;
diff --git a/libcxx/test/std/atomics/atomics.ref/compare_exchange_weak.pass.cpp b/libcxx/test/std/atomics/atomics.ref/compare_exchange_weak.pass.cpp
index 5219a8e3714f9..99c1385a2fe0b 100644
--- a/libcxx/test/std/atomics/atomics.ref/compare_exchange_weak.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.ref/compare_exchange_weak.pass.cpp
@@ -9,6 +9,9 @@
// XFAIL: !has-64-bit-atomics
// XFAIL: !has-1024-bit-atomics
+// MSVC warning C4310: cast truncates constant value
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4310
+
// bool compare_exchange_weak(T&, T, memory_order, memory_order) const noexcept;
// bool compare_exchange_weak(T&, T, memory_order = memory_order::seq_cst) const noexcept;
diff --git a/libcxx/test/std/atomics/atomics.ref/wait.pass.cpp b/libcxx/test/std/atomics/atomics.ref/wait.pass.cpp
index e5310febf5c5e..f246803ba2592 100644
--- a/libcxx/test/std/atomics/atomics.ref/wait.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.ref/wait.pass.cpp
@@ -11,6 +11,9 @@
// XFAIL: !has-64-bit-atomics
// XFAIL: !has-1024-bit-atomics
+// MSVC warning C4310: cast truncates constant value
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4310
+
// void wait(T, memory_order = memory_order::seq_cst) const noexcept;
#include <atomic>
>From 190a6343ab73aacf6402b6ccd47d17135c2d98e4 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl at nuwen.net>
Date: Sun, 19 May 2024 16:26:19 -0700
Subject: [PATCH 5/5] MSVC no longer emits warning C4521 'multiple copy
constructors specified'.
Since at least MSVC-PR-368907 on 2021-12-09.
---
libcxx/test/support/msvc_stdlib_force_include.h | 1 -
1 file changed, 1 deletion(-)
diff --git a/libcxx/test/support/msvc_stdlib_force_include.h b/libcxx/test/support/msvc_stdlib_force_include.h
index 6c26085e72c45..35783c1607b0e 100644
--- a/libcxx/test/support/msvc_stdlib_force_include.h
+++ b/libcxx/test/support/msvc_stdlib_force_include.h
@@ -67,7 +67,6 @@ const AssertionDialogAvoider assertion_dialog_avoider{};
// Silence compiler warnings.
# pragma warning(disable : 4180) // qualifier applied to function type has no meaning; ignored
# pragma warning(disable : 4324) // structure was padded due to alignment specifier
-# pragma warning(disable : 4521) // multiple copy constructors specified
# pragma warning(disable : 4702) // unreachable code
# pragma warning(disable : 28251) // Inconsistent annotation for 'new': this instance has no annotations.
#endif // !defined(__clang__)
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