[clang] [C++17] Support __GCC_[CON|DE]STRUCTIVE_SIZE (PR #89446)
Aaron Ballman via cfe-commits
cfe-commits at lists.llvm.org
Mon Apr 22 11:44:36 PDT 2024
https://github.com/AaronBallman updated https://github.com/llvm/llvm-project/pull/89446
>From 9d394964d3d04c9d7ffd753751f2aaa3a96c9480 Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron at aaronballman.com>
Date: Fri, 19 Apr 2024 15:56:54 -0400
Subject: [PATCH 1/3] [C++17] Support __GCC_[CON|DE]STRUCTIVE_SIZE
These macros are used by STL implementations to support implementation
of std::hardware_destructive_interference_size and
std::hardware_constructive_interference_size
Fixes #60174
---
clang/docs/ReleaseNotes.rst | 13 +++++
clang/include/clang/Basic/TargetInfo.h | 5 ++
clang/lib/Frontend/InitPreprocessor.cpp | 7 +++
clang/test/Preprocessor/init-aarch64.c | 12 +++--
clang/test/Preprocessor/init.c | 49 +++++++++++--------
.../test/Preprocessor/predefined-win-macros.c | 6 ++-
6 files changed, 65 insertions(+), 27 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index aea8fda35bb29c..7414856fd6a03e 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -89,6 +89,19 @@ sections with improvements to Clang's support for those languages.
C++ Language Changes
--------------------
+C++17 Feature Support
+^^^^^^^^^^^^^^^^^^^^^
+- Clang now exposes ``__GCC_DESTRUCTIVE_SIZE`` and ``__GCC_CONSTRUCTIVE_SIZE``
+ predefined macros to support standard library implementations of
+ ``std::hardware_destructive_interference_size`` and
+ ``std::hardware_constructive_interference_size``, respectively. These macros
+ are predefined in all C and C++ language modes. These macros can be
+ overridden on the command line with ``-D``, if desired. The values the macros
+ expand to are not stable between releases of Clang and do not need to match
+ the values produced by GCC, so these macros should not be used from header
+ files because they may not be stable across multiple TUs (the values may vary
+ based on compiler version as well as CPU tuning). #GH60174
+
C++20 Feature Support
^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/include/clang/Basic/TargetInfo.h b/clang/include/clang/Basic/TargetInfo.h
index e1ef7454f01669..a7b112a41f1b99 100644
--- a/clang/include/clang/Basic/TargetInfo.h
+++ b/clang/include/clang/Basic/TargetInfo.h
@@ -1792,6 +1792,11 @@ class TargetInfo : public TransferrableTargetInfo,
/// Whether to support HIP image/texture API's.
virtual bool hasHIPImageSupport() const { return true; }
+ /// The minimum offset between two objects to avoid false sharing.
+ virtual unsigned hardwareDestructiveInterferenceSize() const { return 64; }
+ // The maximum size of contiguous memory to promote true sharing.
+ virtual unsigned hardwareConstructiveInterferenceSize() const { return 64; }
+
protected:
/// Copy type and layout related info.
void copyAuxTarget(const TargetInfo *Aux);
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 4f44c3b7b89d4d..b88cd86e09fa1e 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -1309,6 +1309,13 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
Builder.defineMacro("__GCC_ATOMIC_TEST_AND_SET_TRUEVAL", "1");
}
+ // GCC defines these macros in both C and C++ modes despite them being needed
+ // mostly for STL implementations in C++.
+ Builder.defineMacro("__GCC_DESTRUCTIVE_SIZE",
+ Twine(TI.hardwareDestructiveInterferenceSize()));
+ Builder.defineMacro("__GCC_CONSTRUCTIVE_SIZE",
+ Twine(TI.hardwareConstructiveInterferenceSize()));
+
auto addLockFreeMacros = [&](const llvm::Twine &Prefix) {
// Used by libc++ and libstdc++ to implement ATOMIC_<foo>_LOCK_FREE.
#define DEFINE_LOCK_FREE_MACRO(TYPE, Type) \
diff --git a/clang/test/Preprocessor/init-aarch64.c b/clang/test/Preprocessor/init-aarch64.c
index cf96870b27acb3..f0845985c9efc3 100644
--- a/clang/test/Preprocessor/init-aarch64.c
+++ b/clang/test/Preprocessor/init-aarch64.c
@@ -119,6 +119,8 @@
// AARCH64-NEXT: #define __FP_FAST_FMA 1
// AARCH64-NEXT: #define __FP_FAST_FMAF 1
// AARCH64-NEXT: #define __GCC_ASM_FLAG_OUTPUTS__ 1
+// AARCH64-NEXT: #define __GCC_CONSTRUCTIVE_SIZE {{.+}}
+// AARCH64-NEXT: #define __GCC_DESTRUCTIVE_SIZE {{.+}}
// AARCH64-NEXT: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
// AARCH64-NEXT: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_16 1
// AARCH64-NEXT: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
@@ -220,11 +222,11 @@
// AARCH64-NEXT: #define __LONG_MAX__ 9223372036854775807L
// AARCH64-NEXT: #define __LONG_WIDTH__ 64
// AARCH64-NEXT: #define __LP64__ 1
-// AARCH64-NEXT: #define __MEMORY_SCOPE_DEVICE 1
-// AARCH64-NEXT: #define __MEMORY_SCOPE_SINGLE 4
-// AARCH64-NEXT: #define __MEMORY_SCOPE_SYSTEM 0
-// AARCH64-NEXT: #define __MEMORY_SCOPE_WRKGRP 2
-// AARCH64-NEXT: #define __MEMORY_SCOPE_WVFRNT 3
+// AARCH64-NEXT: #define __MEMORY_SCOPE_DEVICE 1
+// AARCH64-NEXT: #define __MEMORY_SCOPE_SINGLE 4
+// AARCH64-NEXT: #define __MEMORY_SCOPE_SYSTEM 0
+// AARCH64-NEXT: #define __MEMORY_SCOPE_WRKGRP 2
+// AARCH64-NEXT: #define __MEMORY_SCOPE_WVFRNT 3
// AARCH64-NEXT: #define __NO_INLINE__ 1
// AARCH64-NEXT: #define __NO_MATH_ERRNO__ 1
// AARCH64-NEXT: #define __OBJC_BOOL_IS_BOOL 0
diff --git a/clang/test/Preprocessor/init.c b/clang/test/Preprocessor/init.c
index c4a55efca6f712..2641fee940231f 100644
--- a/clang/test/Preprocessor/init.c
+++ b/clang/test/Preprocessor/init.c
@@ -1,3 +1,10 @@
+// RUN: %clang_cc1 -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix INTERFERENCE %s
+//
+// We purposefully do not test the values produced, only that the macros are
+// predefined to some value.
+// INTERFERENCE:#define __GCC_CONSTRUCTIVE_SIZE {{.+}}
+// INTERFERENCE:#define __GCC_DESTRUCTIVE_SIZE {{.+}}
+
// RUN: %clang_cc1 -E -dM -x assembler-with-cpp < /dev/null | FileCheck -match-full-lines -check-prefix ASM %s
//
// ASM:#define __ASSEMBLER__ 1
@@ -1697,6 +1704,8 @@
// WEBASSEMBLY-NEXT:#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
// WEBASSEMBLY-NEXT:#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
// WEBASSEMBLY-NEXT:#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
+// WEBASSEMBLY-NEXT:#define __GCC_CONSTRUCTIVE_SIZE {{.+}}
+// WEBASSEMBLY-NEXT:#define __GCC_DESTRUCTIVE_SIZE {{.+}}
// WEBASSEMBLY-NEXT:#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
// WEBASSEMBLY-NEXT:#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
// WEBASSEMBLY-NEXT:#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
@@ -1806,11 +1815,11 @@
// WEBASSEMBLY64-NEXT:#define __LONG_MAX__ 9223372036854775807L
// WEBASSEMBLY64-NEXT:#define __LONG_WIDTH__ 64
// WEBASSEMBLY64-NEXT:#define __LP64__ 1
-// WEBASSEMBLY-NEXT:#define __MEMORY_SCOPE_DEVICE 1
-// WEBASSEMBLY-NEXT:#define __MEMORY_SCOPE_SINGLE 4
-// WEBASSEMBLY-NEXT:#define __MEMORY_SCOPE_SYSTEM 0
-// WEBASSEMBLY-NEXT:#define __MEMORY_SCOPE_WRKGRP 2
-// WEBASSEMBLY-NEXT:#define __MEMORY_SCOPE_WVFRNT 3
+// WEBASSEMBLY-NEXT:#define __MEMORY_SCOPE_DEVICE 1
+// WEBASSEMBLY-NEXT:#define __MEMORY_SCOPE_SINGLE 4
+// WEBASSEMBLY-NEXT:#define __MEMORY_SCOPE_SYSTEM 0
+// WEBASSEMBLY-NEXT:#define __MEMORY_SCOPE_WRKGRP 2
+// WEBASSEMBLY-NEXT:#define __MEMORY_SCOPE_WVFRNT 3
// WEBASSEMBLY-NEXT:#define __NO_INLINE__ 1
// WEBASSEMBLY-NEXT:#define __NO_MATH_ERRNO__ 1
// WEBASSEMBLY-NEXT:#define __OBJC_BOOL_IS_BOOL 0
@@ -2126,11 +2135,11 @@
// AVR:#define __LDBL_MIN__ 1.17549435e-38L
// AVR:#define __LONG_LONG_MAX__ 9223372036854775807LL
// AVR:#define __LONG_MAX__ 2147483647L
-// AVR:#define __MEMORY_SCOPE_DEVICE 1
-// AVR:#define __MEMORY_SCOPE_SINGLE 4
-// AVR:#define __MEMORY_SCOPE_SYSTEM 0
-// AVR:#define __MEMORY_SCOPE_WRKGRP 2
-// AVR:#define __MEMORY_SCOPE_WVFRNT 3
+// AVR:#define __MEMORY_SCOPE_DEVICE 1
+// AVR:#define __MEMORY_SCOPE_SINGLE 4
+// AVR:#define __MEMORY_SCOPE_SYSTEM 0
+// AVR:#define __MEMORY_SCOPE_WRKGRP 2
+// AVR:#define __MEMORY_SCOPE_WVFRNT 3
// AVR:#define __NO_INLINE__ 1
// AVR:#define __ORDER_BIG_ENDIAN__ 4321
// AVR:#define __ORDER_LITTLE_ENDIAN__ 1234
@@ -2422,11 +2431,11 @@
// RISCV32: #define __LITTLE_ENDIAN__ 1
// RISCV32: #define __LONG_LONG_MAX__ 9223372036854775807LL
// RISCV32: #define __LONG_MAX__ 2147483647L
-// RISCV32: #define __MEMORY_SCOPE_DEVICE 1
-// RISCV32: #define __MEMORY_SCOPE_SINGLE 4
-// RISCV32: #define __MEMORY_SCOPE_SYSTEM 0
-// RISCV32: #define __MEMORY_SCOPE_WRKGRP 2
-// RISCV32: #define __MEMORY_SCOPE_WVFRNT 3
+// RISCV32: #define __MEMORY_SCOPE_DEVICE 1
+// RISCV32: #define __MEMORY_SCOPE_SINGLE 4
+// RISCV32: #define __MEMORY_SCOPE_SYSTEM 0
+// RISCV32: #define __MEMORY_SCOPE_WRKGRP 2
+// RISCV32: #define __MEMORY_SCOPE_WVFRNT 3
// RISCV32: #define __NO_INLINE__ 1
// RISCV32: #define __POINTER_WIDTH__ 32
// RISCV32: #define __PRAGMA_REDEFINE_EXTNAME 1
@@ -2634,11 +2643,11 @@
// RISCV64: #define __LONG_LONG_MAX__ 9223372036854775807LL
// RISCV64: #define __LONG_MAX__ 9223372036854775807L
// RISCV64: #define __LP64__ 1
-// RISCV64: #define __MEMORY_SCOPE_DEVICE 1
-// RISCV64: #define __MEMORY_SCOPE_SINGLE 4
-// RISCV64: #define __MEMORY_SCOPE_SYSTEM 0
-// RISCV64: #define __MEMORY_SCOPE_WRKGRP 2
-// RISCV64: #define __MEMORY_SCOPE_WVFRNT 3
+// RISCV64: #define __MEMORY_SCOPE_DEVICE 1
+// RISCV64: #define __MEMORY_SCOPE_SINGLE 4
+// RISCV64: #define __MEMORY_SCOPE_SYSTEM 0
+// RISCV64: #define __MEMORY_SCOPE_WRKGRP 2
+// RISCV64: #define __MEMORY_SCOPE_WVFRNT 3
// RISCV64: #define __NO_INLINE__ 1
// RISCV64: #define __POINTER_WIDTH__ 64
// RISCV64: #define __PRAGMA_REDEFINE_EXTNAME 1
diff --git a/clang/test/Preprocessor/predefined-win-macros.c b/clang/test/Preprocessor/predefined-win-macros.c
index b830dc39d477dd..14e2f584bd0938 100644
--- a/clang/test/Preprocessor/predefined-win-macros.c
+++ b/clang/test/Preprocessor/predefined-win-macros.c
@@ -3,7 +3,7 @@
// RUN: %clang_cc1 %s -x c++ -E -dM -triple x86_64-pc-win32 -fms-extensions -fms-compatibility \
// RUN: -fms-compatibility-version=19.00 -std=c++14 -o - | FileCheck -match-full-lines %s --check-prefix=CHECK-MS64
// RUN: %clang_cc1 %s -x c++ -E -dM -triple x86_64-pc-win32 -fms-extensions -fms-compatibility \
-// RUN: -fms-compatibility-version=19.00 -std=c++14 -o - | grep GCC | count 5
+// RUN: -fms-compatibility-version=19.00 -std=c++14 -o - | grep GCC | count 7
// CHECK-MS64: #define _INTEGRAL_MAX_BITS 64
// CHECK-MS64: #define _ISO_VOLATILE 1
// CHECK-MS64: #define _MSC_EXTENSIONS 1
@@ -26,7 +26,7 @@
// RUN: %clang_cc1 %s -x c++ -E -dM -triple i686-pc-win32 -fms-extensions -fms-compatibility \
// RUN: -fms-compatibility-version=19.00 -std=c++17 -o - | FileCheck -match-full-lines %s --check-prefix=CHECK-MS
// RUN: %clang_cc1 %s -x c++ -E -dM -triple i686-pc-win32 -fms-extensions -fms-compatibility \
-// RUN: -fms-compatibility-version=19.00 -std=c++17 -o - | grep GCC | count 5
+// RUN: -fms-compatibility-version=19.00 -std=c++17 -o - | grep GCC | count 7
// CHECK-MS: #define _INTEGRAL_MAX_BITS 64
// CHECK-MS: #define _ISO_VOLATILE 1
// CHECK-MS: #define _MSC_EXTENSIONS 1
@@ -39,6 +39,8 @@
// CHECK-MS-NOT: GNU
// CHECK-MS-NOT: GXX
// CHECK-MS: #define __GCC_ASM_FLAG_OUTPUTS__ 1
+// CHECK-MS: #define __GCC_CONSTRUCTIVE_SIZE {{.+}}
+// CHECK-MS: #define __GCC_DESTRUCTIVE_SIZE {{.+}}
// CHECK-MS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
// CHECK-MS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
// CHECK-MS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
>From 658a329bd820af181c00a54d0df74d36e86e0387 Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron at aaronballman.com>
Date: Mon, 22 Apr 2024 12:04:16 -0400
Subject: [PATCH 2/3] Handle SystemZ
---
clang/lib/Basic/Targets/SystemZ.h | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/clang/lib/Basic/Targets/SystemZ.h b/clang/lib/Basic/Targets/SystemZ.h
index 8e302acd51b8ad..189d8a5ac87de4 100644
--- a/clang/lib/Basic/Targets/SystemZ.h
+++ b/clang/lib/Basic/Targets/SystemZ.h
@@ -220,6 +220,13 @@ class LLVM_LIBRARY_VISIBILITY SystemZTargetInfo : public TargetInfo {
int getEHDataRegisterNumber(unsigned RegNo) const override {
return RegNo < 4 ? 6 + RegNo : -1;
}
+
+ virtual unsigned hardwareDestructiveInterferenceSize() const override {
+ return 256;
+ }
+ virtual unsigned hardwareConstructiveInterferenceSize() const override {
+ return 256;
+ }
};
} // namespace targets
} // namespace clang
>From 6b6da8f3f763eda12633da12e8f08669de2cc469 Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron at aaronballman.com>
Date: Mon, 22 Apr 2024 14:44:07 -0400
Subject: [PATCH 3/3] Remove mention of using -D from the release notes
---
clang/docs/ReleaseNotes.rst | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 7414856fd6a03e..337649371b6ead 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -95,8 +95,7 @@ C++17 Feature Support
predefined macros to support standard library implementations of
``std::hardware_destructive_interference_size`` and
``std::hardware_constructive_interference_size``, respectively. These macros
- are predefined in all C and C++ language modes. These macros can be
- overridden on the command line with ``-D``, if desired. The values the macros
+ are predefined in all C and C++ language modes. The values the macros
expand to are not stable between releases of Clang and do not need to match
the values produced by GCC, so these macros should not be used from header
files because they may not be stable across multiple TUs (the values may vary
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