crash in wasm-ld

[zapashcanon]

Hi,

I got a crash while using wasm-ld. Here's the full command and output:

$ dune exec -- owi c -O3 -vv --testcomp bench/testcomp/sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.shift_register_top_w128_d8_e0.c 
owi: [EXEC:216699] ['/usr/bin/clang' '-O3' '--target=wasm32' '-m32'
                    '-ffreestanding' '--no-standard-libraries'
                    '-Wno-everything' '-flto=thin' '-Wl,--entry=main'
                    '-Wl,--export=main' '-Wl,--lto-O0'
                    '-Wl,-z,stack-size=8388608' '-I'
                    '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files'
                    '-o' '/tmp/owi_c_ebc58a/a.out.wasm'
                    '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libc.wasm'
                    '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libowi.wasm'
                    'bench/testcomp/sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.shift_register_top_w128_d8_e0.c']
wasm-ld-19: warning: function signature mismatch: free
>>> defined as (i32) -> i32 in /home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libowi.wasm
>>> defined as (i32) -> void in /home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libc.wasm
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /usr/bin/wasm-ld-19 -m wasm32 -L/usr/lib --entry=main --export=main --lto-O0 -z stack-size=8388608 /home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libc.wasm /home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libowi.wasm /tmp/btor2c-lazyMod-fa4c77.o -o /tmp/owi_c_ebc58a/a.out.wasm --keep-section=target_features
 #0 0x00007f3d24ab06ba llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/lib/x86_64-linux-gnu/libLLVM.so.19.1+0xeb06ba)
 #1 0x00007f3d24aae264 llvm::sys::RunSignalHandlers() (/lib/x86_64-linux-gnu/libLLVM.so.19.1+0xeae264)
 #2 0x00007f3d24ab0d7b (/lib/x86_64-linux-gnu/libLLVM.so.19.1+0xeb0d7b)
 #3 0x00007f3d23649df0 (/lib/x86_64-linux-gnu/libc.so.6+0x3fdf0)
 #4 0x00005651bd8181c4 lld::wasm::TableSymbol::getTableNumber() const (/usr/bin/wasm-ld-19+0x4511c4)
 #5 0x00005651bd839f3e lld::wasm::ElemSection::writeBody() (/usr/bin/wasm-ld-19+0x472f3e)
 #6 0x00005651bd8264de (/usr/bin/wasm-ld-19+0x45f4de)
 #7 0x00005651bd822220 (/usr/bin/wasm-ld-19+0x45b220)
 #8 0x00005651bd8186fa lld::wasm::writeResult() (/usr/bin/wasm-ld-19+0x4516fa)
 #9 0x00005651bd7fb5d9 (/usr/bin/wasm-ld-19+0x4345d9)
#10 0x00005651bd7f6ede lld::wasm::link(llvm::ArrayRef<char const*>, llvm::raw_ostream&, llvm::raw_ostream&, bool, bool) (/usr/bin/wasm-ld-19+0x42fede)
#11 0x00005651bd49d192 lld::unsafeLldMain(llvm::ArrayRef<char const*>, llvm::raw_ostream&, llvm::raw_ostream&, llvm::ArrayRef<lld::DriverDef>, bool) (/usr/bin/wasm-ld-19+0xd6192)
#12 0x00005651bd49c41f lld_main(int, char**, llvm::ToolContext const&) (/usr/bin/wasm-ld-19+0xd541f)
#13 0x00005651bd49ca5a main (/usr/bin/wasm-ld-19+0xd5a5a)
#14 0x00007f3d23633ca8 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#15 0x00007f3d23633d65 call_init ./csu/../csu/libc-start.c:128:20
#16 0x00007f3d23633d65 __libc_start_main ./csu/../csu/libc-start.c:347:5
#17 0x00005651bd49c061 _start (/usr/bin/wasm-ld-19+0xd5061)
clang: error: unable to execute command: Segmentation fault
clang: error: linker command failed due to signal (use -v to see invocation)
owi: [DEBUG] clang failed: run ['/usr/bin/clang' '-O3' '--target=wasm32' '-m32' '-ffreestanding'
     '--no-standard-libraries' '-Wno-everything' '-flto=thin'
     '-Wl,--entry=main' '-Wl,--export=main' '-Wl,--lto-O0'
     '-Wl,-z,stack-size=8388608' '-I'
     '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files'
     '-o' '/tmp/owi_c_ebc58a/a.out.wasm'
     '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libc.wasm'
     '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libowi.wasm'
     'bench/testcomp/sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.shift_register_top_w128_d8_e0.c']: exited with 1
owi: [ERROR] clang failed (run with -vv if the full error message is not displayed above)

I can provide more information if needed.

This is on:

$ wasm-ld --version
Debian LLD 19.1.7

The bug is not here on an older version:

$ wasm-ld --version
Ubuntu LLD 18.1.3

But there seems to be something strange in the older version too. The only thing I have in my C code is:

__attribute__((import_module("symbolic"), import_name("v128_symbol"))) __int128 owi_int128(void);
__attribute__((import_module("symbolic"), import_name("v128_symbol"))) unsigned __int128 owi_uint128(void);

But I am ending with the following Wasm import:

(type (;1;) (func (param i32)))
(import "symbolic" "v128_symbol" (func $owi_uint128 (type 1)))

Which is wrong (it should have type (func (result i32)) and not (func (param i32)).

[llvmbot]

@llvm/issue-subscribers-lld-wasm

Author: None (zapashcanon)

Hi,

I got a crash while using wasm-ld. Here's the full command and output:

$ dune exec -- owi c -O3 -vv --testcomp bench/testcomp/sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.shift_register_top_w128_d8_e0.c 
owi: [EXEC:216699] ['/usr/bin/clang' '-O3' '--target=wasm32' '-m32'
                    '-ffreestanding' '--no-standard-libraries'
                    '-Wno-everything' '-flto=thin' '-Wl,--entry=main'
                    '-Wl,--export=main' '-Wl,--lto-O0'
                    '-Wl,-z,stack-size=8388608' '-I'
                    '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files'
                    '-o' '/tmp/owi_c_ebc58a/a.out.wasm'
                    '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libc.wasm'
                    '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libowi.wasm'
                    'bench/testcomp/sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.shift_register_top_w128_d8_e0.c']
wasm-ld-19: warning: function signature mismatch: free
>>> defined as (i32) -> i32 in /home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libowi.wasm
>>> defined as (i32) -> void in /home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libc.wasm
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /usr/bin/wasm-ld-19 -m wasm32 -L/usr/lib --entry=main --export=main --lto-O0 -z stack-size=8388608 /home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libc.wasm /home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libowi.wasm /tmp/btor2c-lazyMod-fa4c77.o -o /tmp/owi_c_ebc58a/a.out.wasm --keep-section=target_features
 #<!-- -->0 0x00007f3d24ab06ba llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) (/lib/x86_64-linux-gnu/libLLVM.so.19.1+0xeb06ba)
 #<!-- -->1 0x00007f3d24aae264 llvm::sys::RunSignalHandlers() (/lib/x86_64-linux-gnu/libLLVM.so.19.1+0xeae264)
 #<!-- -->2 0x00007f3d24ab0d7b (/lib/x86_64-linux-gnu/libLLVM.so.19.1+0xeb0d7b)
 #<!-- -->3 0x00007f3d23649df0 (/lib/x86_64-linux-gnu/libc.so.6+0x3fdf0)
 #<!-- -->4 0x00005651bd8181c4 lld::wasm::TableSymbol::getTableNumber() const (/usr/bin/wasm-ld-19+0x4511c4)
 #<!-- -->5 0x00005651bd839f3e lld::wasm::ElemSection::writeBody() (/usr/bin/wasm-ld-19+0x472f3e)
 #<!-- -->6 0x00005651bd8264de (/usr/bin/wasm-ld-19+0x45f4de)
 #<!-- -->7 0x00005651bd822220 (/usr/bin/wasm-ld-19+0x45b220)
 #<!-- -->8 0x00005651bd8186fa lld::wasm::writeResult() (/usr/bin/wasm-ld-19+0x4516fa)
 #<!-- -->9 0x00005651bd7fb5d9 (/usr/bin/wasm-ld-19+0x4345d9)
#<!-- -->10 0x00005651bd7f6ede lld::wasm::link(llvm::ArrayRef&lt;char const*&gt;, llvm::raw_ostream&amp;, llvm::raw_ostream&amp;, bool, bool) (/usr/bin/wasm-ld-19+0x42fede)
#<!-- -->11 0x00005651bd49d192 lld::unsafeLldMain(llvm::ArrayRef&lt;char const*&gt;, llvm::raw_ostream&amp;, llvm::raw_ostream&amp;, llvm::ArrayRef&lt;lld::DriverDef&gt;, bool) (/usr/bin/wasm-ld-19+0xd6192)
#<!-- -->12 0x00005651bd49c41f lld_main(int, char**, llvm::ToolContext const&amp;) (/usr/bin/wasm-ld-19+0xd541f)
#<!-- -->13 0x00005651bd49ca5a main (/usr/bin/wasm-ld-19+0xd5a5a)
#<!-- -->14 0x00007f3d23633ca8 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#<!-- -->15 0x00007f3d23633d65 call_init ./csu/../csu/libc-start.c:128:20
#<!-- -->16 0x00007f3d23633d65 __libc_start_main ./csu/../csu/libc-start.c:347:5
#<!-- -->17 0x00005651bd49c061 _start (/usr/bin/wasm-ld-19+0xd5061)
clang: error: unable to execute command: Segmentation fault
clang: error: linker command failed due to signal (use -v to see invocation)
owi: [DEBUG] clang failed: run ['/usr/bin/clang' '-O3' '--target=wasm32' '-m32' '-ffreestanding'
     '--no-standard-libraries' '-Wno-everything' '-flto=thin'
     '-Wl,--entry=main' '-Wl,--export=main' '-Wl,--lto-O0'
     '-Wl,-z,stack-size=8388608' '-I'
     '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files'
     '-o' '/tmp/owi_c_ebc58a/a.out.wasm'
     '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libc.wasm'
     '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libowi.wasm'
     'bench/testcomp/sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.shift_register_top_w128_d8_e0.c']: exited with 1
owi: [ERROR] clang failed (run with -vv if the full error message is not displayed above)

I can provide more information if needed.

This is on:

$ wasm-ld --version
Debian LLD 19.1.7

The bug is not here on an older version:

$ wasm-ld --version
Ubuntu LLD 18.1.3

[EugeneZelenko]

Could you please try 20 or main branch?

[zapashcanon]

Same issue with llvm-20 from debian:experimental:

$ dune exec -- owi c -O3 -vv --testcomp bench/testcomp/sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.shift_register_top_w128_d8_e0.c
owi: [EXEC:224993] ['/usr/bin/clang' '-O3' '--target=wasm32' '-m32'
                    '-ffreestanding' '--no-standard-libraries'
                    '-Wno-everything' '-flto=thin' '-Wl,--entry=main'
                    '-Wl,--export=main' '-Wl,--lto-O0'
                    '-Wl,-z,stack-size=8388608' '-I'
                    '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files'
                    '-o' '/tmp/owi_c_84e7e1/a.out.wasm'
                    '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libc.wasm'
                    '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libowi.wasm'
                    'bench/testcomp/sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.shift_register_top_w128_d8_e0.c']
wasm-ld-20: warning: function signature mismatch: free
>>> defined as (i32) -> i32 in /home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libowi.wasm
>>> defined as (i32) -> void in /home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libc.wasm
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /usr/bin/wasm-ld-20 -m wasm32 -L/usr/lib --entry=main --export=main --lto-O0 -z stack-size=8388608 /home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libc.wasm /home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libowi.wasm /tmp/btor2c-lazyMod-631f66.o -o /tmp/owi_c_84e7e1/a.out.wasm --keep-section=target_features
 #0 0x00007f8bf1c001ca llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/lib/x86_64-linux-gnu/libLLVM.so.20.1+0x48001ca)
 #1 0x00007f8bf1bfdd64 llvm::sys::RunSignalHandlers() (/lib/x86_64-linux-gnu/libLLVM.so.20.1+0x47fdd64)
 #2 0x00007f8bf1c0087b (/lib/x86_64-linux-gnu/libLLVM.so.20.1+0x480087b)
 #3 0x00007f8bece49df0 (/lib/x86_64-linux-gnu/libc.so.6+0x3fdf0)
 #4 0x00005621f6fd2a84 lld::wasm::TableSymbol::getTableNumber() const (/usr/bin/wasm-ld-20+0x523a84)
 #5 0x00005621f6fec502 lld::wasm::ElemSection::writeBody() (/usr/bin/wasm-ld-20+0x53d502)
 #6 0x00005621f6fe042e (/usr/bin/wasm-ld-20+0x53142e)
 #7 0x00005621f6fdc180 (/usr/bin/wasm-ld-20+0x52d180)
 #8 0x00005621f6fd2fba lld::wasm::writeResult() (/usr/bin/wasm-ld-20+0x523fba)
 #9 0x00005621f6fb4a0c (/usr/bin/wasm-ld-20+0x505a0c)
#10 0x00005621f6fb033e lld::wasm::link(llvm::ArrayRef<char const*>, llvm::raw_ostream&, llvm::raw_ostream&, bool, bool) (/usr/bin/wasm-ld-20+0x50133e)
#11 0x00005621f6c24cae lld::unsafeLldMain(llvm::ArrayRef<char const*>, llvm::raw_ostream&, llvm::raw_ostream&, llvm::ArrayRef<lld::DriverDef>, bool) (/usr/bin/wasm-ld-20+0x175cae)
#12 0x00005621f6c23ed2 lld_main(int, char**, llvm::ToolContext const&) (/usr/bin/wasm-ld-20+0x174ed2)
#13 0x00005621f6c2459a main (/usr/bin/wasm-ld-20+0x17559a)
#14 0x00007f8bece33ca8 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#15 0x00007f8bece33d65 call_init ./csu/../csu/libc-start.c:128:20
#16 0x00007f8bece33d65 __libc_start_main ./csu/../csu/libc-start.c:347:5
#17 0x00005621f6c23b11 _start (/usr/bin/wasm-ld-20+0x174b11)
clang: error: unable to execute command: Segmentation fault
clang: error: linker command failed due to signal (use -v to see invocation)
owi: [DEBUG] clang failed: run ['/usr/bin/clang' '-O3' '--target=wasm32' '-m32' '-ffreestanding'
     '--no-standard-libraries' '-Wno-everything' '-flto=thin'
     '-Wl,--entry=main' '-Wl,--export=main' '-Wl,--lto-O0'
     '-Wl,-z,stack-size=8388608' '-I'
     '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files'
     '-o' '/tmp/owi_c_84e7e1/a.out.wasm'
     '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libc.wasm'
     '/home/zapashcanon/dev/ml/owi/_build/install/default/share/owi/c_files/libowi.wasm'
     'bench/testcomp/sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.shift_register_top_w128_d8_e0.c']: exited with 1
owi: [ERROR] clang failed (run with -vv if the full error message is not displayed above)

[sbc100]

I think this likely relates to adding support for multiple tables back in 53e3b81 and 388fb67.

I seem to remember another open bug that is similar.. I'll try to find it.

[sbc100]

Maybe related to emscripten-core/emscripten#23965

[zapashcanon]

A few informations:

• I am not using emscripten but calling clang/wasm-ld by hand directly;
• the issue appeared only after adding a v128 function imported from Wasm.

I even managed to minimize the diff quite a lot:

OCamlPro/owi@8a90670

This code has nothing special compared to what is done in the same file, we imports a lot of other functions in the same way. This one has only a special thing: it uses v128 so I suspect it has something to do with it. I hope this helps.