Stop using __attribute__((retain)) in GCC builds

[MatzeB]

GCC sometimes produces warnings about __attribute__((retain)) despite __has_attribute(retain) being 1. See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99587

The amount of users who benefit from the attribute is probably very small compared to the amount of -Werror enabled builds or the desire to keep -Wattributes enabled in the LLVM build. So for now drop usage of the retain attribute in GCC builds.

[llvmbot]

@llvm/pr-subscribers-llvm-support

Author: Matthias Braun (MatzeB)

Changes

GCC sometimes produces warnings about __attribute__((retain)) despite __has_attribute(retain) being 1. See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99587

The amount of users who benefit from the attribute is probably very small compared to the amount of -Werror enabled builds or the desire to keep -Wattributes enabled in the LLVM build. So for now drop usage of the retain attribute in GCC builds.

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Full diff: https://github.com/llvm/llvm-project/pull/133793.diff

1 Files Affected:

• (modified) llvm/include/llvm/Support/Compiler.h (+7)

diff --git a/llvm/include/llvm/Support/Compiler.h b/llvm/include/llvm/Support/Compiler.h
index ff6f5e44ae2f1..dd70362455d89 100644
--- a/llvm/include/llvm/Support/Compiler.h
+++ b/llvm/include/llvm/Support/Compiler.h
@@ -231,8 +231,15 @@
 #endif
 
 #if __has_attribute(retain)
+#if defined(__clang__) || !defined(__GNUC__)
 #define LLVM_ATTRIBUTE_RETAIN __attribute__((__retain__))
 #else
+// See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99587
+// GCC may produce "warning: ‘retain’ attribute ignored" (despite
+// __has_attribute(retain) begin 1). For now skip the attribute on GCC.
+#define LLVM_ATTRIBUTE_RETAIN
+#endif
+#else
 #define LLVM_ATTRIBUTE_RETAIN
 #endif
 

[makslevental]

@MatzeB is this ready to merge? Would be nice to have this in.

[llvm-ci]

LLVM Buildbot has detected a new failure on builder llvm-clang-aarch64-darwin running on doug-worker-4 while building llvm at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/17516

Here is the relevant piece of the build log for the reference

Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
/Users/buildbot/buildbot-root/aarch64-darwin/build/bin/lli -jit-kind=orc-lazy -compile-threads=2 -thread-entry hello /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll | /Users/buildbot/buildbot-root/aarch64-darwin/build/bin/FileCheck /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll # RUN: at line 1
+ /Users/buildbot/buildbot-root/aarch64-darwin/build/bin/lli -jit-kind=orc-lazy -compile-threads=2 -thread-entry hello /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll
+ /Users/buildbot/buildbot-root/aarch64-darwin/build/bin/FileCheck /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
 #0 0x0000000102f560e8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/Users/buildbot/buildbot-root/aarch64-darwin/build/bin/lli+0x100eca0e8)
 #1 0x0000000102f5416c llvm::sys::RunSignalHandlers() (/Users/buildbot/buildbot-root/aarch64-darwin/build/bin/lli+0x100ec816c)
 #2 0x0000000102f567a4 SignalHandler(int, __siginfo*, void*) (/Users/buildbot/buildbot-root/aarch64-darwin/build/bin/lli+0x100eca7a4)
 #3 0x0000000189db6584 (/usr/lib/system/libsystem_platform.dylib+0x18047a584)
 #4 0x0000000189d8521c (/usr/lib/system/libsystem_pthread.dylib+0x18044921c)
 #5 0x0000000189cabad0 (/usr/lib/libc++.1.dylib+0x18036fad0)
 #6 0x0000000102afd0e0 void llvm::detail::UniqueFunctionBase<void, llvm::Expected<llvm::DenseMap<llvm::orc::SymbolStringPtr, llvm::orc::ExecutorSymbolDef, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void>, llvm::detail::DenseMapPair<llvm::orc::SymbolStringPtr, llvm::orc::ExecutorSymbolDef>>>>::CallImpl<llvm::orc::Platform::lookupInitSymbols(llvm::orc::ExecutionSession&, llvm::DenseMap<llvm::orc::JITDylib*, llvm::orc::SymbolLookupSet, llvm::DenseMapInfo<llvm::orc::JITDylib*, void>, llvm::detail::DenseMapPair<llvm::orc::JITDylib*, llvm::orc::SymbolLookupSet>> const&)::$_45>(void*, llvm::Expected<llvm::DenseMap<llvm::orc::SymbolStringPtr, llvm::orc::ExecutorSymbolDef, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void>, llvm::detail::DenseMapPair<llvm::orc::SymbolStringPtr, llvm::orc::ExecutorSymbolDef>>>&) (/Users/buildbot/buildbot-root/aarch64-darwin/build/bin/lli+0x100a710e0)
 #7 0x0000000102af8d14 llvm::orc::AsynchronousSymbolQuery::handleComplete(llvm::orc::ExecutionSession&)::RunQueryCompleteTask::run() (/Users/buildbot/buildbot-root/aarch64-darwin/build/bin/lli+0x100a6cd14)
 #8 0x0000000102bb4aac void* std::__1::__thread_proxy[abi:un170006]<std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct>>, llvm::orc::DynamicThreadPoolTaskDispatcher::dispatch(std::__1::unique_ptr<llvm::orc::Task, std::__1::default_delete<llvm::orc::Task>>)::$_0>>(void*) (/Users/buildbot/buildbot-root/aarch64-darwin/build/bin/lli+0x100b28aac)
 #9 0x0000000189d85f94 (/usr/lib/system/libsystem_pthread.dylib+0x180449f94)
#10 0x0000000189d80d34 (/usr/lib/system/libsystem_pthread.dylib+0x180444d34)
FileCheck error: '<stdin>' is empty.
FileCheck command line:  /Users/buildbot/buildbot-root/aarch64-darwin/build/bin/FileCheck /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll

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