clang inserts undefined reference to __mulodi4

[alexcohn]

Description

Build of sqlite3.c for armeabi-v7a with clang fails in NDK r15c:

sqlite3.c:function sqlite3MulInt64: error: undefined reference to '__mulodi4'

Here is the minimal command to reproduce this:

void q(long long qq) {
    __builtin_mul_overflow(qq, qq, &qq);
}

clang -arch arm --sysroot $NDK_ROOT/sysroot -c q.c && nm q.o

Note a similar issue in Chromium: https://bugs.chromium.org/p/chromium/issues/detail?id=503229.
sqlite3.c does not use __builtin_mul_overflow for CLANG_VERSION under 4000000, hence build succeeds in NDK 14.

Environment Details

• NDK Version: 15.2.4203891
• Build sytem: ndk-build
• Host OS: Mac
• Compiler: clang version 5.0.300080
• ABI: armeabi-v7a

[fornwall]

I think #294 is the canonical issue for functions provided by compiler-rt.

[alexcohn]

@fornwall thanks for the link. It doesn't seem a duplicate though, because my example is 32-bit. Are we really expected to compile mulodi4.c?

[enh]

duplicate of issue #184 .

[unanan]

Same question about the undefined reference to '__mulodi4' Error

[dibya001]

Was anyone able to resolve this issue. Still facing the same error.

[mhsmith]

Fixed in NDK r19, according to #294.