wasmtime/runtime/vm/
debug_builtins.rs

1#![doc(hidden)]
2
3use crate::runtime::vm::{Instance, VMContext};
4use core::ptr::NonNull;
5use wasmtime_environ::{EntityRef, MemoryIndex};
6use wasmtime_versioned_export_macros::versioned_export;
7
8static mut VMCTX_AND_MEMORY: (NonNull<VMContext>, usize) = (NonNull::dangling(), 0);
9
10// These implementations are referenced from C code in "helpers.c". The symbols defined
11// there (prefixed by "wasmtime_") are the real 'public' interface used in the debug info.
12
13#[versioned_export]
14pub unsafe extern "C" fn resolve_vmctx_memory_ptr(p: *const u32) -> *const u8 {
15    unsafe {
16        let ptr = core::ptr::read(p);
17        assert!(
18            VMCTX_AND_MEMORY.0 != NonNull::dangling(),
19            "must call `__vmctx->set()` before resolving Wasm pointers"
20        );
21        Instance::enter_host_from_wasm(VMCTX_AND_MEMORY.0, |store, instance| {
22            let handle = store.instance_mut(instance);
23            assert!(
24                VMCTX_AND_MEMORY.1 < handle.env_module().memories.len(),
25                "memory index for debugger is out of bounds"
26            );
27            let index = MemoryIndex::new(VMCTX_AND_MEMORY.1);
28            let mem = handle.get_memory(index);
29            mem.base.as_ptr().add(ptr as usize)
30        })
31    }
32}
33
34#[versioned_export]
35pub unsafe extern "C" fn set_vmctx_memory(vmctx_ptr: *mut VMContext) {
36    unsafe {
37        // TODO multi-memory
38        VMCTX_AND_MEMORY = (NonNull::new(vmctx_ptr).unwrap(), 0);
39    }
40}
41
42/// A bit of a hack around various linkage things. The goal here is to force the
43/// `wasmtime_*` symbols defined in `helpers.c` to actually get exported. That
44/// means they need to be referenced for the linker to include them which is
45/// what this function does with trickery in C.
46pub fn init() {
47    unsafe extern "C" {
48        #[wasmtime_versioned_export_macros::versioned_link]
49        fn wasmtime_debug_builtins_init();
50    }
51
52    unsafe {
53        wasmtime_debug_builtins_init();
54    }
55}
wasmtime/runtime/vm/debug_builtins.rs

wasmtime/runtime/vm/
debug_builtins.rs
