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Immediately perform relocations when defining a function

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This commit is contained in:
bjorn3
2020-11-12 16:33:04 +01:00
parent 5458473765
commit 8a4749af51
1 changed files with 14 additions and 22 deletions
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36
cranelift/simplejit/src/backend.rs
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@@ -137,7 +137,6 @@ pub struct SimpleJITModule {
libcall_plt_entries: HashMap<ir::LibCall, NonNull<[u8; 16]>>,
compiled_functions: SecondaryMap<FuncId, Option<CompiledBlob>>,
compiled_data_objects: SecondaryMap<DataId, Option<CompiledBlob>>,
functions_to_finalize: Vec<FuncId>,
data_objects_to_finalize: Vec<DataId>,
}
@@ -171,7 +170,10 @@ impl SimpleJITModule {
}
unsafe fn write_plt_entry_bytes(plt_ptr: *mut [u8; 16], got_ptr: *mut *const u8) {
assert!(cfg!(target_arch = "x86_64"), "PLT is currently only supported on x86_64");
assert!(
cfg!(target_arch = "x86_64"),
"PLT is currently only supported on x86_64"
);
// jmp *got_ptr; ud2; ud2; ud2; ud2; ud2
let mut plt_val = [
0xff, 0x25, 0, 0, 0, 0, 0x0f, 0x0b, 0x0f, 0x0b, 0x0f, 0x0b, 0x0f, 0x0b, 0x0f, 0x0b,
@@ -274,10 +276,6 @@ impl SimpleJITModule {
/// Returns the address of a finalized function.
pub fn get_finalized_function(&self, func_id: FuncId) -> *const u8 {
let info = &self.compiled_functions[func_id];
assert!(
!self.functions_to_finalize.iter().any(|x| *x == func_id),
"function not yet finalized"
);
info.as_ref()
.expect("function must be compiled before it can be finalized")
.ptr
@@ -321,18 +319,6 @@ impl SimpleJITModule {
/// Use `get_finalized_function` and `get_finalized_data` to obtain the final
/// artifacts.
pub fn finalize_definitions(&mut self) {
for func in std::mem::take(&mut self.functions_to_finalize) {
let decl = self.declarations.get_function_decl(func);
assert!(decl.linkage.is_definable());
let func_blob = self.compiled_functions[func]
.as_ref()
.expect("function must be compiled before it can be finalized");
func_blob.perform_relocations(
|name| unreachable!("non-GOT/PLT relocation in function {} to {}", func, name),
|name| self.get_got_address(name),
|name| self.get_plt_address(name),
);
}
for data in std::mem::take(&mut self.data_objects_to_finalize) {
let decl = self.declarations.get_data_decl(data);
assert!(decl.linkage.is_definable());
@@ -411,7 +397,6 @@ impl SimpleJITModule {
libcall_plt_entries,
compiled_functions: SecondaryMap::new(),
compiled_data_objects: SecondaryMap::new(),
functions_to_finalize: Vec::new(),
data_objects_to_finalize: Vec::new(),
}
}
@@ -582,11 +567,14 @@ impl<'simple_jit_backend> Module for SimpleJITModule {
size,
relocs: reloc_sink.relocs,
});
// FIXME immediately perform relocations
self.functions_to_finalize.push(id);
unsafe {
std::ptr::write(self.function_got_entries[id].unwrap().as_ptr(), ptr);
}
self.compiled_functions[id].as_ref().unwrap().perform_relocations(
|name| unreachable!("non GOT or PLT relocation in function {} to {}", id, name),
|name| self.get_got_address(name),
|name| self.get_plt_address(name),
);
Ok(ModuleCompiledFunction { size: code_size })
}
@@ -629,10 +617,14 @@ impl<'simple_jit_backend> Module for SimpleJITModule {
size,
relocs: relocs.to_vec(),
});
self.functions_to_finalize.push(id);
unsafe {
std::ptr::write(self.function_got_entries[id].unwrap().as_ptr(), ptr);
}
self.compiled_functions[id].as_ref().unwrap().perform_relocations(
|name| unreachable!("non GOT or PLT relocation in function {} to {}", id, name),
|name| self.get_got_address(name),
|name| self.get_plt_address(name),
);
Ok(ModuleCompiledFunction { size: total_size })
}