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Support declaring anonymous functions and data objects

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This commit is contained in:
bjorn3
2021-03-21 18:00:26 +01:00
parent 8e43e96410
commit cc89111463
3 changed files with 189 additions and 56 deletions
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123
cranelift/jit/src/backend.rs
View File

@@ -180,6 +180,53 @@ impl JITModule {
.or_else(|| lookup_with_dlsym(name))
}
fn new_func_plt_entry(&mut self, id: FuncId, val: *const u8) {
let got_entry = self
.memory
.writable
.allocate(
std::mem::size_of::<*const u8>(),
std::mem::align_of::<*const u8>().try_into().unwrap(),
)
.unwrap()
.cast::<*const u8>();
self.function_got_entries[id] = Some(NonNull::new(got_entry).unwrap());
unsafe {
std::ptr::write(got_entry, val);
}
let plt_entry = self
.memory
.code
.allocate(std::mem::size_of::<[u8; 16]>(), EXECUTABLE_DATA_ALIGNMENT)
.unwrap()
.cast::<[u8; 16]>();
self.record_function_for_perf(
plt_entry as *mut _,
std::mem::size_of::<[u8; 16]>(),
&format!("{}@plt", self.declarations.get_function_decl(id).name),
);
self.function_plt_entries[id] = Some(NonNull::new(plt_entry).unwrap());
unsafe {
Self::write_plt_entry_bytes(plt_entry, got_entry);
}
}
fn new_data_got_entry(&mut self, id: DataId, val: *const u8) {
let got_entry = self
.memory
.writable
.allocate(
std::mem::size_of::<*const u8>(),
std::mem::align_of::<*const u8>().try_into().unwrap(),
)
.unwrap()
.cast::<*const u8>();
self.data_object_got_entries[id] = Some(NonNull::new(got_entry).unwrap());
unsafe {
std::ptr::write(got_entry, val);
}
}
unsafe fn write_plt_entry_bytes(plt_ptr: *mut [u8; 16], got_ptr: *mut *const u8) {
assert!(
cfg!(target_arch = "x86_64"),
@@ -488,40 +535,25 @@ impl Module for JITModule {
linkage: Linkage,
signature: &ir::Signature,
) -> ModuleResult<FuncId> {
let (id, _decl) = self
let (id, linkage) = self
.declarations
.declare_function(name, linkage, signature)?;
if self.function_got_entries[id].is_none() && self.isa.flags().is_pic() {
let got_entry = self
.memory
.writable
.allocate(
std::mem::size_of::<*const u8>(),
std::mem::align_of::<*const u8>().try_into().unwrap(),
)
.unwrap()
.cast::<*const u8>();
self.function_got_entries[id] = Some(NonNull::new(got_entry).unwrap());
// FIXME populate got entries with a null pointer when defined
let val = self.lookup_symbol(name).unwrap_or(std::ptr::null());
unsafe {
std::ptr::write(got_entry, val);
}
let plt_entry = self
.memory
.code
.allocate(std::mem::size_of::<[u8; 16]>(), EXECUTABLE_DATA_ALIGNMENT)
.unwrap()
.cast::<[u8; 16]>();
self.record_function_for_perf(
plt_entry as *mut _,
std::mem::size_of::<[u8; 16]>(),
&format!("{}@plt", name),
);
self.function_plt_entries[id] = Some(NonNull::new(plt_entry).unwrap());
unsafe {
Self::write_plt_entry_bytes(plt_entry, got_entry);
}
let val = if linkage == Linkage::Import {
self.lookup_symbol(name).unwrap_or(std::ptr::null())
} else {
std::ptr::null()
};
self.new_func_plt_entry(id, val);
}
Ok(id)
}
fn declare_anonymous_function(&mut self, signature: &ir::Signature) -> ModuleResult<FuncId> {
let id = self.declarations.declare_anonymous_function(signature)?;
if self.isa.flags().is_pic() {
self.new_func_plt_entry(id, std::ptr::null());
}
Ok(id)
}
@@ -534,25 +566,26 @@ impl Module for JITModule {
tls: bool,
) -> ModuleResult<DataId> {
assert!(!tls, "JIT doesn't yet support TLS");
let (id, _decl) = self
let (id, linkage) = self
.declarations
.declare_data(name, linkage, writable, tls)?;
if self.data_object_got_entries[id].is_none() && self.isa.flags().is_pic() {
let got_entry = self
.memory
.writable
.allocate(
std::mem::size_of::<*const u8>(),
std::mem::align_of::<*const u8>().try_into().unwrap(),
)
.unwrap()
.cast::<*const u8>();
self.data_object_got_entries[id] = Some(NonNull::new(got_entry).unwrap());
// FIXME populate got entries with a null pointer when defined
let val = self.lookup_symbol(name).unwrap_or(std::ptr::null());
unsafe {
std::ptr::write(got_entry, val);
}
let val = if linkage == Linkage::Import {
self.lookup_symbol(name).unwrap_or(std::ptr::null())
} else {
std::ptr::null()
};
self.new_data_got_entry(id, val);
}
Ok(id)
}
fn declare_anonymous_data(&mut self, writable: bool, tls: bool) -> ModuleResult<DataId> {
assert!(!tls, "JIT doesn't yet support TLS");
let id = self.declarations.declare_anonymous_data(writable, tls)?;
if self.isa.flags().is_pic() {
self.new_data_got_entry(id, std::ptr::null());
}
Ok(id)
}