1 #![doc(hidden)]
2 
3 use crate::runtime::vm::{Instance, VMContext};
4 use core::ptr::NonNull;
5 use wasmtime_environ::{EntityRef, MemoryIndex};
6 use wasmtime_versioned_export_macros::versioned_export;
7 
8 static 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]
14 pub 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, handle| {
22             assert!(
23                 VMCTX_AND_MEMORY.1 < handle.env_module().memories.len(),
24                 "memory index for debugger is out of bounds"
25             );
26             let index = MemoryIndex::new(VMCTX_AND_MEMORY.1);
27             let mem = handle.get_memory(index);
28             mem.base.as_ptr().add(ptr as usize)
29         })
30     }
31 }
32 
33 #[versioned_export]
34 pub unsafe extern "C" fn set_vmctx_memory(vmctx_ptr: *mut VMContext) {
35     unsafe {
36         // TODO multi-memory
37         VMCTX_AND_MEMORY = (NonNull::new(vmctx_ptr).unwrap(), 0);
38     }
39 }
40 
41 /// A bit of a hack around various linkage things. The goal here is to force the
42 /// `wasmtime_*` symbols defined in `helpers.c` to actually get exported. That
43 /// means they need to be referenced for the linker to include them which is
44 /// what this function does with trickery in C.
45 pub fn init() {
46     unsafe extern "C" {
47         #[wasmtime_versioned_export_macros::versioned_link]
48         fn wasmtime_debug_builtins_init();
49     }
50 
51     unsafe {
52         wasmtime_debug_builtins_init();
53     }
54 }
55