1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
From 1202a4d9577e296effc258915226a2732368075d Mon Sep 17 00:00:00 2001
From: levlam <levlam@telegram.org>
Date: Mon, 19 Feb 2024 16:31:00 +0300
Subject: [PATCH] Use
https://github.com/libjxl/libjxl/blob/main/cmake/FindAtomics.cmake to find
libatomic.
Signed-off-by: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
---
CMake/FindAtomics.cmake | 53 +++++++++++++++++++++++++++++++++++++++++
CMakeLists.txt | 5 ++++
2 files changed, 58 insertions(+)
create mode 100644 CMake/FindAtomics.cmake
--- /dev/null
+++ b/CMake/FindAtomics.cmake
@@ -0,0 +1,53 @@
+# Original issue:
+# * https://gitlab.kitware.com/cmake/cmake/-/issues/23021#note_1098733
+#
+# For reference:
+# * https://gcc.gnu.org/wiki/Atomic/GCCMM
+#
+# riscv64 specific:
+# * https://lists.debian.org/debian-riscv/2022/01/msg00009.html
+#
+# ATOMICS_FOUND - system has c++ atomics
+# ATOMICS_LIBRARIES - libraries needed to use c++ atomics
+
+include(CheckCXXSourceCompiles)
+
+# RISC-V only has 32-bit and 64-bit atomic instructions. GCC is supposed
+# to convert smaller atomics to those larger ones via masking and
+# shifting like LLVM, but it’s a known bug that it does not. This means
+# anything that wants to use atomics on 1-byte or 2-byte types needs
+# -latomic, but not 4-byte or 8-byte (though it does no harm).
+set(atomic_code
+ "
+ #include <atomic>
+ #include <cstdint>
+ std::atomic<uint8_t> n8 (0); // riscv64
+ std::atomic<uint64_t> n64 (0); // armel, mipsel, powerpc
+ int main() {
+ ++n8;
+ ++n64;
+ return 0;
+ }")
+
+check_cxx_source_compiles("${atomic_code}" ATOMICS_LOCK_FREE_INSTRUCTIONS)
+
+if (ATOMICS_LOCK_FREE_INSTRUCTIONS)
+ set(ATOMICS_FOUND TRUE)
+ set(ATOMICS_LIBRARIES)
+else()
+ set(CMAKE_REQUIRED_LIBRARIES "-latomic")
+ check_cxx_source_compiles("${atomic_code}" ATOMICS_IN_LIBRARY)
+ set(CMAKE_REQUIRED_LIBRARIES)
+ if (ATOMICS_IN_LIBRARY)
+ set(ATOMICS_LIBRARY atomic)
+ include(FindPackageHandleStandardArgs)
+ find_package_handle_standard_args(Atomics DEFAULT_MSG ATOMICS_LIBRARY)
+ set(ATOMICS_LIBRARIES ${ATOMICS_LIBRARY})
+ unset(ATOMICS_LIBRARY)
+ else()
+ if (Atomics_FIND_REQUIRED)
+ message(FATAL_ERROR "Neither lock free instructions nor -latomic found.")
+ endif()
+ endif()
+endif()
+unset(atomic_code)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -132,6 +132,11 @@
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pthread")
endif()
+find_package(Atomics REQUIRED)
+if (ATOMICS_LIBRARIES)
+ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${ATOMICS_LIBRARIES}")
+endif()
+
include(TdSetUpCompiler)
td_set_up_compiler()
|
