gentoo/dev-db/mongodb/files/mongodb-8.0.8-sconstruct.patch
Z. Liu 575b35af90
dev-db/mongodb: fix build issue w/ clang 20
upstream patch is applied, otherwise the build w/ clang 20 fails with:

> src/mongo/bson/util/bsoncolumnbuilder.h:285:49: error: call to deleted constructor of 'const mongo::TrackingAllocator<void> &'

However, the build still fails with:

> /usr/bin/x86_64-pc-linux-gnu-ld.bfd: build/gentoo/mongo/db/storage/wiredtiger/wiredtiger_record_store.o: in function `mongo::WiredTigerRecordStore::getEarliestOplogTimestamp(mongo::OperationContext*)':
> /usr/lib/gcc/x86_64-pc-linux-gnu/14/include/g++-v14/bits/atomic_base.h:1002:(.text+0x7da9): undefined reference to `__atomic_compare_exchange'
> clang++: error: linker command failed with exit code 1 (use -v to see invocation)

The reason is that Timestamp is a composite type, which requires -latomic
when building with clang++ and libstdc++. Mongodb's SConstruct only
checks for some basic types ('int64_t', 'uint64_t', 'int32_t', 'uint32_t'),
so this case is not detected.

Test case below:

$ cat a.cc
#include <atomic>
struct Timestamp { unsigned int t, i; };
template<typename T> struct AtomicWord {
    std::atomic<T> v;
    T compareAndSwap(T e, T n) {
        v.compare_exchange_strong(e,n); return e;
    }
};
int main() {
    AtomicWord<Timestamp> x;
    Timestamp a{0,0}, b{1,1};
    x.compareAndSwap(a,b);
    return 0;
}

$ clang++ -stdlib=libstdc++ a.cc
/usr/bin/x86_64-pc-linux-gnu-ld.bfd: /tmp/a-1e3f91.o: in function `std::atomic<Timestamp>::compare_exchange_strong(Timestamp&, Timestamp, std::memory_order, std::memory_order)':
a.cc:(.text._ZNSt6atomicI9TimestampE23compare_exchange_strongERS0_S0_St12memory_orderS3_[_ZNSt6atomicI9TimestampE23compare_exchange_strongERS0_S0_St12memory_orderS3_]+0x222): undefined reference to `__atomic_compare_exchange'
/usr/bin/x86_64-pc-linux-gnu-ld.bfd: a.cc:(.text._ZNSt6atomicI9TimestampE23compare_exchange_strongERS0_S0_St12memory_orderS3_[_ZNSt6atomicI9TimestampE23compare_exchange_strongERS0_S0_St12memory_orderS3_]+0x28d): undefined reference to `__atomic_compare_exchange'
/usr/bin/x86_64-pc-linux-gnu-ld.bfd: a.cc:(.text._ZNSt6atomicI9TimestampE23compare_exchange_strongERS0_S0_St12memory_orderS3_[_ZNSt6atomicI9TimestampE23compare_exchange_strongERS0_S0_St12memory_orderS3_]+0x2f8): undefined reference to `__atomic_compare_exchange'
/usr/bin/x86_64-pc-linux-gnu-ld.bfd: a.cc:(.text._ZNSt6atomicI9TimestampE23compare_exchange_strongERS0_S0_St12memory_orderS3_[_ZNSt6atomicI9TimestampE23compare_exchange_strongERS0_S0_St12memory_orderS3_]+0x3c1): undefined reference to `__atomic_compare_exchange'
/usr/bin/x86_64-pc-linux-gnu-ld.bfd: a.cc:(.text._ZNSt6atomicI9TimestampE23compare_exchange_strongERS0_S0_St12memory_orderS3_[_ZNSt6atomicI9TimestampE23compare_exchange_strongERS0_S0_St12memory_orderS3_]+0x42c): undefined reference to `__atomic_compare_exchange'
/usr/bin/x86_64-pc-linux-gnu-ld.bfd: /tmp/a-1e3f91.o:a.cc:(.text._ZNSt6atomicI9TimestampE23compare_exchange_strongERS0_S0_St12memory_orderS3_[_ZNSt6atomicI9TimestampE23compare_exchange_strongERS0_S0_St12memory_orderS3_]+0x497): more undefined references to `__atomic_compare_exchange' follow
clang++: error: linker command failed with exit code 1 (use -v to see invocation)

Signed-off-by: Z. Liu <zhixu.liu@gmail.com>
Part-of: https://github.com/gentoo/gentoo/pull/43808
Closes: https://github.com/gentoo/gentoo/pull/43808
Signed-off-by: Sam James <sam@gentoo.org>
2025-09-17 22:27:44 +01:00

46 lines
1.8 KiB
Diff

check whether "-latomic" is required for composite type, see src/mongo/bson/timestamp.h,
otherwise the build fails with:
> /usr/bin/x86_64-pc-linux-gnu-ld.bfd: build/gentoo/mongo/db/storage/wiredtiger/wiredtiger_record_store.o: in function `mongo::WiredTigerRecordStore::getEarliestOplogTimestamp(mongo::OperationContext*)':
> /usr/lib/gcc/x86_64-pc-linux-gnu/14/include/g++-v14/bits/atomic_base.h:1002:(.text+0x7da9): undefined reference to `__atomic_compare_exchange'
> clang++: error: linker command failed with exit code 1 (use -v to see invocation)
diff --git a/SConstruct b/SConstruct
index 2a32456..4cfb5fd 100644
--- a/SConstruct
+++ b/SConstruct
@@ -5369,10 +5369,33 @@ def doConfigure(myenv):
conf.AddTest("CheckStdAtomic", CheckStdAtomic)
+ def CheckTimestampAtomic(context, extra_message):
+ test_body = """
+ #include <atomic>
+ struct Timestamp { unsigned int t, i; };
+ template<typename T> struct AtomicWord { std::atomic<T> v; T compareAndSwap(T e, T n) { v.compare_exchange_strong(e,n); return e; } };
+ int main() {
+ AtomicWord<Timestamp> x;
+ Timestamp a{0,0}, b{1,1};
+ x.compareAndSwap(a,b);
+ return 0;
+ }
+ """
+
+ context.Message("Checking if AtomicWord<Timestamp> works{0}... ".format(extra_message))
+
+ ret = context.TryLink(textwrap.dedent(test_body), ".cpp")
+ context.Result(ret)
+ return ret
+
+ conf.AddTest("CheckTimestampAtomic", CheckTimestampAtomic)
+
def check_all_atomics(extra_message=''):
for t in ('int64_t', 'uint64_t', 'int32_t', 'uint32_t'):
if not conf.CheckStdAtomic(t, extra_message):
return False
+ if not conf.CheckTimestampAtomic(extra_message):
+ return False
return True
if not check_all_atomics():