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Replace the global-exports mechanism with a caller-vmctx mechanism. (#789)

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* Replace the global-exports mechanism with a caller-vmctx mechanism.

This eliminates the global exports mechanism, and instead adds a
caller-vmctx argument to wasm functions so that WASI can obtain the
memory and other things from the caller rather than looking them up in a
global registry.

This replaces #390.

* Fixup some merge conflicts

* Rustfmt

* Ensure VMContext is aligned to 16 bytes

With the removal of `global_exports` it "just so happens" that this
isn't happening naturally any more.

* Fixup some bugs with double vmctx in wasmtime crate

* Trampoline stub needed adjusting
* Use pointer type instead of always using I64 for caller vmctx
* Don't store `ir::Signature` in `Func` since we don't know the pointer
  size at creation time.
* Skip the first 2 arguments in IR signatures since that's the two vmctx
  parameters.

* Update cranelift to 0.56.0

* Handle more merge conflicts

* Rustfmt

Co-authored-by: Alex Crichton <alex@alexcrichton.com>
This commit is contained in:
Dan Gohman
2020-01-21 14:50:59 -08:00
committed by GitHub
parent de72435576
commit 9a88d3d894
33 changed files with 362 additions and 330 deletions
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15
crates/runtime/src/traphandlers.rs
View File

@@ -13,10 +13,11 @@ use wasmtime_environ::ir;
extern "C" {
fn WasmtimeCallTrampoline(
vmctx: *mut u8,
caller_vmctx: *mut u8,
callee: *const VMFunctionBody,
values_vec: *mut u8,
) -> i32;
fn WasmtimeCall(vmctx: *mut u8, callee: *const VMFunctionBody) -> i32;
fn WasmtimeCall(vmctx: *mut u8, caller_vmctx: *mut u8, callee: *const VMFunctionBody) -> i32;
}
thread_local! {
@@ -165,10 +166,17 @@ fn trap_code_to_expected_string(trap_code: ir::TrapCode) -> String {
#[no_mangle]
pub unsafe extern "C" fn wasmtime_call_trampoline(
vmctx: *mut VMContext,
caller_vmctx: *mut VMContext,
callee: *const VMFunctionBody,
values_vec: *mut u8,
) -> Result<(), Trap> {
if WasmtimeCallTrampoline(vmctx as *mut u8, callee, values_vec) == 0 {
if WasmtimeCallTrampoline(
vmctx as *mut u8,
caller_vmctx as *mut u8,
callee,
values_vec,
) == 0
{
Err(last_trap())
} else {
Ok(())
@@ -180,9 +188,10 @@ pub unsafe extern "C" fn wasmtime_call_trampoline(
#[no_mangle]
pub unsafe extern "C" fn wasmtime_call(
vmctx: *mut VMContext,
caller_vmctx: *mut VMContext,
callee: *const VMFunctionBody,
) -> Result<(), Trap> {
if WasmtimeCall(vmctx as *mut u8, callee) == 0 {
if WasmtimeCall(vmctx as *mut u8, caller_vmctx as *mut u8, callee) == 0 {
Err(last_trap())
} else {
Ok(())