wasmtime / issue #11830 "Couldn't materialize" any expres... · git-wasmtime

clang -c --target=wasm32 -o a.o a.c -g
wasm-ld -o a.wasm a.o --import-memory --no-entry --export=func
clang -o b b.c -Wall -Wextra -fsanitize=address -g \
    -I wasmtime-37.0.1.2/include -L wasmtime-37.0.1.2/lib -l wasmtime

void func() {
    int s = 0;
    for (int i = 0; i < 5; i++) {
        s += i;
    }
}

#include <stdio.h>
#include <assert.h>
#include <wasm.h>
#include <wasmtime.h>

int main() {
    wasm_trap_t* trap = NULL;
    wasmtime_error_t* err = NULL;

    wasm_config_t* config = wasm_config_new();
    wasmtime_config_debug_info_set(config, true);
    wasmtime_config_cranelift_opt_level_set(config, WASMTIME_OPT_LEVEL_NONE);

    wasm_engine_t* engine = wasm_engine_new_with_config(config);
    wasmtime_store_t* store = wasmtime_store_new(engine, NULL, NULL);
    wasmtime_context_t* cx = wasmtime_store_context(store);
    wasmtime_linker_t* linker = wasmtime_linker_new(engine);
    wasm_limits_t limits = { .min = 256, .max = UINT32_MAX };
    wasm_memorytype_t* mem_ty = wasm_memorytype_new(&limits);
    wasmtime_memory_t  memory;

    err = wasmtime_memory_new(cx, mem_ty, &memory);
    assert(!err);
    wasm_memorytype_delete(mem_ty);
    wasmtime_extern_t mem_extern = {
        .kind = WASMTIME_EXTERN_MEMORY,
        .of = {
          .memory = memory,
        },
    };
    err = wasmtime_linker_define(linker, cx, "env", 3, "memory", 6, &mem_extern);
    assert(!err);

    FILE* f = fopen("a.wasm", "rb");
    assert(f);
    fseek(f, 0, SEEK_END);
    size_t n = ftell(f);
    fseek(f, 0, SEEK_SET);
    wasm_byte_vec_t bytes;
    wasm_byte_vec_new_uninitialized(&bytes, n);
    fread(bytes.data, n, 1, f);
    fclose(f);

    wasmtime_module_t* module = NULL;
    err = wasmtime_module_new(engine, (uint8_t*)bytes.data, bytes.size, &module);
    assert(!err);
    wasm_byte_vec_delete(&bytes);
    wasmtime_instance_t instance = {};
    err = wasmtime_linker_instantiate(linker, cx, module, &instance, &trap);
    assert(!err);

    wasmtime_extern_t item = {};
    bool success = wasmtime_instance_export_get(cx, &instance, "func", 4, &item);
    assert(success);
    assert(item.kind == WASMTIME_EXTERN_FUNC);
    err = wasmtime_func_call(cx, &item.of.func, NULL, 0, NULL, 0, &trap);
    assert(!err);

    return 0;
}

Steps to Reproduce

lldb b -b -o "b func" -o "r" -o "n" -o "n" -o "p s"

Note: You will need to create the file ~/.lldbinit with the following contents if not already:

settings set plugin.jit-loader.gdb.enable on

Expected Results

Actual Results

error: Couldn't materialize: couldn't get the value of variable s: variable not available
error: errored out in DoExecute, couldn't PrepareToExecuteJITExpression

Versions and Environment

Extra Info

There is an existing issue with something similar: https://github.com/bytecodealliance/wasmtime/issues/11337. However that issue is only in the case "after indirect call", while this issue is that variables cannot be displayed at all.

Stream: git-wasmtime

Topic: wasmtime / issue #11830 "Couldn't materialize" any expres...

Wasmtime GitHub notifications bot (Oct 10 2025 at 13:21):

Test Case