Likely validation bug related to memory alignment.

[teyahb8]

Subject of the issue

I executed the following test case on different runtimes. Other runtimes that support the "Exception Handling" proposal would output "Exception: unreachable". But, after building WAMR with "Exception Handling" proposal, both WAMR AOT and JIT mode outputs a validation error "alignment must not be larger than natural".

In the test case, there is an instruction i32.store offset=1916 align=2. If the validation error occurs due to the alignment value on this instruction, can you please recheck if there indeed should be a validation error? According to the specification of store operation, "The alignment 2^memarg.align must not be larger than the bit width of 𝑡 divided by 8." For an i32 instruction, 𝑡 divided by 8 should be 4, and 2^(align=2) should also be 4. So, this seems to be a valid alignment.

Test case

(module
  (type (;0;) (func (param i32 i32 i32 i32) (result i32)))
  (type (;1;) (func (param i32)))
  (type (;2;) (func))
  (type (;3;) (func (result i32)))
  (table (;0;) 10 20 funcref)
  (memory (;0;) 1 5)
  (global (;0;) i32 i32.const 541)
  (global (;1;) (mut i32) i32.const 191)
  (global (;2;) f32 f32.const 0x1.0e8p+9 (;=541;))
  (global (;3;) (mut f32) f32.const 0x1.8p+7 (;=192;))
  (global (;4;) i64 i64.const 54)
  (global (;5;) (mut i64) i64.const 19)
  (global (;6;) f64 f64.const 0x1.bp+5 (;=54;))
  (global (;7;) (mut f64) f64.const 0x1.3p+4 (;=19;))
  (global (;8;) (mut i32) i32.const 0)
  (global (;9;) (mut f32) f32.const 0x0p+0 (;=0;))
  (global (;10;) (mut i64) i64.const 0)
  (global (;11;) (mut f64) f64.const 0x0p+0 (;=0;))
  (export "main" (func 0))
  (export "to_test" (func 0))
  (elem (;0;) (i32.const 0) func 1 2 3 0 1)
  (elem (;1;) (i32.const 5) func 3 3 2 1)
  (elem (;2;) (i32.const 9) func 0)
  (func (;0;) (type 2)
    (local i32 f32 i64 f64)
    i32.const 305419896
    local.set 0
    f32.const 0x1.8cp+6 (;=99;)
    local.set 1
    i64.const -72057589709208571
    local.set 2
    f64.const 0x1.5f0b08c960a79p+109 (;=890000000000000000000000000000000;)
    local.set 3
    unreachable
    i32.const -62
    unreachable
    i32.store offset=1916 align=2
    unreachable
    throw_ref
    local.get 0
    global.set 8
    local.get 1
    global.set 9
    local.get 2
    global.set 10
    local.get 3
    global.set 11
  )
  (func (;1;) (type 3) (result i32)
    i32.const 1
    i32.const 3
    i32.add
  )
  (func (;2;) (type 3) (result i32)
    i32.const 2
    i32.const 3
    i32.add
  )
  (func (;3;) (type 3) (result i32)
    i32.const 3
    i32.const 3
    i32.add
  )
  (data (;0;) (i32.const 8) "\01\02\03\04\05\06\07\08")
  (data (;1;) (i32.const 16) "\01\02\03\04\05\06\07\08\ff")
  (data (;2;) (i32.const 32) "\01\02\03\04\05\06\07\08\ff")
)

Your environment

• Host OS (Ubuntu 22.04)
• WAMR version (2.3.1), platform (Linux), cpu architecture (x86_64), running mode (AOT/JIT).

Steps to reproduce

1. AOT: wamrc --bounds-checks=1 -o test.aot test.wasm; iwasm --heap-size=0 -f to_test test.aot
2. JIT: iwasm --heap-size=0 --llvm-jit -f to_test test.wasm

Expected behavior

Output should be: "Exception: unreachable"

Actual behavior

Actually outputs: "WASM module load failed: invalid memop flags: alignment must not be larger than natural"

Extra Info

Can you please confirm if this looks like a validation bug? Thanks in advance.

[teyahb8]

For some additional context, here are the compilation options that I have used:

cmake -DWAMR_BUILD_BULK_MEMORY=1 -DWAMR_BUILD_REF_TYPES=1 -DWAMR_BUILD_SIMD=1 -DWAMR_BUILD_JIT=1 -DLLVM_DIR=/usr/lib/llvm-18/lib/cmake/llvm ..
make -j

What are your thoughts on this likely incorrect alignment error, @Septa2112?