llvm_mode LTO instrumentlist and persistent tests fails on Alpine Linux riscv64

[ncopa]

IMPORTANT

AFLplusplus-4.20c

Describe the bug
On alpine linux, riscv64 the LTO llvm_mode test fails.

[*] Testing: LTO llvm_mode
[!] LTO llvm_mode failed   
[!] llvm_mode LTO instrumentlist feature compilation failed
[!] llvm_mode LTO persistent mode feature compilation failed

To Reproduce

On an Alpin eLinux riscv64 machine run:

        export PATH="$PATH:/usr/lib/llvm17/bin"
        export NO_NYX=1
        export AFL_NO_X86=1
        export LLVM_LTO=1
        make PREFIX=/usr all

        CFLAGS= CXXFLAGS= make AFL_NO_X86=1 test

Expected behavior
Test passes

Screen output/Screenshots

[*] Testing: LTO llvm_mode
[!] LTO llvm_mode failed
[!] llvm_mode LTO instrumentlist feature compilation failed
[!] llvm_mode LTO persistent mode feature compilation failed

Additional context

This was discovered on riscv64.

[vanhauser-thc]

does this work? clang -flto -o test test-instr.c

[vanhauser-thc]

@ncopa ?

[vanhauser-thc]

Also I see in the changelog in the redhat repo:

        # i686 support was silently removed in AFL++ 4.10c

this is not true. maybe there was a bug we were not aware of, but it is working perfectly fine in 4.20+ (as you can test by using our aflplusplus/aflplusplus docker container on docker hub).

the riscv or os390 are likely packaging errors in redhat, otherwise bugs in llvm itself. I do not see how this can be a bug in afl++.

lastly, if you have a redhat for arm64, except outdated afl-gcc/afl-clang instrumentation, everything is working there too.

[ncopa]

does this work? clang -flto -o test test-instr.c

No because there exist a test directory. But I if output it to test1 it does work.

ncopa-edge-riscv64:~/aports/community/afl++/src/AFLplusplus-4.20c$ clang -flto -o test test-instr.c 
/usr/bin/ld: cannot open output file test: Is a directory
clang: error: linker command failed with exit code 1 (use -v to see invocation)
ncopa-edge-riscv64:~/aports/community/afl++/src/AFLplusplus-4.20c$ clang -flto -o test1 test-instr.c
ncopa-edge-riscv64:~/aports/community/afl++/src/AFLplusplus-4.20c$

There is also a utils/persistent_mode/test-instr.c:

ncopa-edge-riscv64:~/aports/community/afl++/src/AFLplusplus-4.20c$ cd utils/persistent_mode/
ncopa-edge-riscv64:~/aports/community/afl++/src/AFLplusplus-4.20c/utils/persistent_mode$ clang -flto -o test test-instr.c 
test-instr.c:22:1: error: type specifier missing, defaults to 'int'; ISO C99 and later do not support implicit int [-Wimplicit-int]
   22 | __AFL_FUZZ_INIT();
      | ^
      | int
test-instr.c:31:3: error: call to undeclared function '__AFL_INIT'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   31 |   __AFL_INIT();
      |   ^
test-instr.c:32:24: error: use of undeclared identifier '__AFL_FUZZ_TESTCASE_BUF'
   32 |   unsigned char *buf = __AFL_FUZZ_TESTCASE_BUF;
      |                        ^
test-instr.c:34:10: error: call to undeclared function '__AFL_LOOP'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   34 |   while (__AFL_LOOP(UINT_MAX)) {  // if you have 100% stability
      |          ^
test-instr.c:36:24: error: use of undeclared identifier '__AFL_FUZZ_TESTCASE_LEN'
   36 |     unsigned int len = __AFL_FUZZ_TESTCASE_LEN;
      |                        ^

But I assume you meant the toplevel file.

[ncopa]

Also I see in the changelog in the redhat repo:

I suppose you should mention that to redhat developers.

lastly, if you have a redhat for arm64,

Unfortunately, I have more than enough work with shipping Alpine releases so I can't help you fix redhat. Sorry.

[vanhauser-thc]

ah I mixed up two different issues, sorry.

so clang -flto works, that rules out that the llvm installation is incomplete (the usual problem).

do you have a link to the build log of afl++ on riscv? I have never used alpine, so ...

and is there an easy way how I could reproduce/debug this? (I have no riscv linux)

[vanhauser-thc]

I experience a problem on Debian riscv64 where LTO is not working, but that stems from two issues - first their binutils do not provide ld.gold and second the llvm-18 from apt.llvm.org is not providing libLLVMgold.so.

My guess is that is similar here.
what does this output?
AFL_PASSTHROUGH=1 ./afl-clang-fast -flto=full -o test-instr test-instr.c