54 lines
1.8 KiB
Diff
54 lines
1.8 KiB
Diff
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From 10fee6d71a1f7d6e6319005196562b4a30b4e8ff Mon Sep 17 00:00:00 2001
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From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
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Date: Tue, 2 Feb 2016 14:58:52 +0100
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Subject: [PATCH] Fix detection of C11 atomics
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Currently, the CMakeLists.txt logic to detect the availability of C11
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atomics is based on building a small program that uses the
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atomic_load().
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However, atomic_load() does not need to use any function from
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libatomic (part of the gcc runtime). So even if libatomic is missing,
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this test concludes that C11 atomic support is available. For example
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on SPARC, the example program builds fine without linking to
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libatomic, but calling other functions of the atomic_*() APIs fail
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without linking to libatomic.
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So, this patch adjusts the CMakeLists.txt test to use a function that
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is known to require the libatomic run-time library (on architectures
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where it is needed). This way, openal will only use the __atomic_*()
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built-ins when they are actually functional.
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Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
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---
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CMakeLists.txt | 7 +++++--
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1 file changed, 5 insertions(+), 2 deletions(-)
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diff --git a/CMakeLists.txt b/CMakeLists.txt
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index 5784d35..a53f996 100644
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--- a/CMakeLists.txt
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+++ b/CMakeLists.txt
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@@ -209,14 +209,17 @@ CHECK_C_SOURCE_COMPILES(
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HAVE_C11_ALIGNAS)
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# Check if we have C11 _Atomic
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+set(OLD_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
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+set(CMAKE_REQUIRED_LIBRARIES ${EXTRA_LIBS})
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CHECK_C_SOURCE_COMPILES(
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"#include <stdatomic.h>
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- const int _Atomic foo = ATOMIC_VAR_INIT(~0);
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+ int _Atomic foo = ATOMIC_VAR_INIT(~0);
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int main()
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{
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- return atomic_load(&foo);
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+ return atomic_fetch_add(&foo, 2);
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}"
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HAVE_C11_ATOMIC)
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+set(CMAKE_REQUIRED_LIBRARIES ${OLD_REQUIRED_LIBRARIES})
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# Add definitions, compiler switches, etc.
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INCLUDE_DIRECTORIES("${OpenAL_SOURCE_DIR}/include" "${OpenAL_BINARY_DIR}")
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--
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2.6.4
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