54 lines
1.8 KiB
Rust
54 lines
1.8 KiB
Rust
#![doc(hidden)]
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use crate::instance::InstanceHandle;
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use crate::vmcontext::VMContext;
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use wasmtime_environ::{EntityRef, MemoryIndex};
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static mut VMCTX_AND_MEMORY: (*mut VMContext, usize) = (std::ptr::null_mut(), 0);
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#[no_mangle]
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pub unsafe extern "C" fn resolve_vmctx_memory(ptr: usize) -> *const u8 {
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let handle = InstanceHandle::from_vmctx(VMCTX_AND_MEMORY.0);
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assert!(
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VMCTX_AND_MEMORY.1 < handle.module().memory_plans.len(),
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"memory index for debugger is out of bounds"
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);
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let index = MemoryIndex::new(VMCTX_AND_MEMORY.1);
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let mem = handle.instance().get_memory(index);
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mem.base.add(ptr)
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}
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#[no_mangle]
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pub unsafe extern "C" fn resolve_vmctx_memory_ptr(p: *const u32) -> *const u8 {
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let ptr = std::ptr::read(p);
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assert!(
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!VMCTX_AND_MEMORY.0.is_null(),
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"must call `__vmctx->set()` before resolving Wasm pointers"
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);
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let handle = InstanceHandle::from_vmctx(VMCTX_AND_MEMORY.0);
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assert!(
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VMCTX_AND_MEMORY.1 < handle.module().memory_plans.len(),
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"memory index for debugger is out of bounds"
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);
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let index = MemoryIndex::new(VMCTX_AND_MEMORY.1);
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let mem = handle.instance().get_memory(index);
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mem.base.add(ptr as usize)
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}
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#[no_mangle]
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pub unsafe extern "C" fn set_vmctx_memory(vmctx_ptr: *mut VMContext) {
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// TODO multi-memory
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VMCTX_AND_MEMORY = (vmctx_ptr, 0);
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}
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// Ensures that set_vmctx_memory and resolve_vmctx_memory_ptr are linked and
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// exported as symbols. It is a workaround: the executable normally ignores
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// `pub extern "C"`, see rust-lang/rust#25057.
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pub fn ensure_exported() {
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unsafe {
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std::ptr::read_volatile(resolve_vmctx_memory_ptr as *const u8);
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std::ptr::read_volatile(set_vmctx_memory as *const u8);
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std::ptr::read_volatile(resolve_vmctx_memory as *const u8);
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}
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}
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