rust/src/declare.rs

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use gccjit::{Function, FunctionType, GlobalKind, LValue, RValue, Type};
#[cfg(feature="master")]
use gccjit::{FnAttribute, ToRValue};
use rustc_codegen_ssa::traits::BaseTypeMethods;
use rustc_middle::ty::Ty;
use rustc_span::Symbol;
use rustc_target::abi::call::FnAbi;
use crate::abi::{FnAbiGcc, FnAbiGccExt};
use crate::context::CodegenCx;
use crate::intrinsic::llvm;
impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
pub fn get_or_insert_global(&self, name: &str, ty: Type<'gcc>, is_tls: bool, link_section: Option<Symbol>) -> LValue<'gcc> {
if self.globals.borrow().contains_key(name) {
let typ = self.globals.borrow()[name].get_type();
let global = self.context.new_global(None, GlobalKind::Imported, typ, name);
if is_tls {
global.set_tls_model(self.tls_model);
}
if let Some(link_section) = link_section {
global.set_link_section(link_section.as_str());
}
global
}
else {
self.declare_global(name, ty, GlobalKind::Exported, is_tls, link_section)
}
}
pub fn declare_unnamed_global(&self, ty: Type<'gcc>) -> LValue<'gcc> {
let name = self.generate_local_symbol_name("global");
self.context.new_global(None, GlobalKind::Internal, ty, &name)
}
pub fn declare_global_with_linkage(&self, name: &str, ty: Type<'gcc>, linkage: GlobalKind) -> LValue<'gcc> {
let global = self.context.new_global(None, linkage, ty, name);
let global_address = global.get_address(None);
self.globals.borrow_mut().insert(name.to_string(), global_address);
global
}
pub fn declare_func(&self, name: &str, return_type: Type<'gcc>, params: &[Type<'gcc>], variadic: bool) -> Function<'gcc> {
self.linkage.set(FunctionType::Extern);
declare_raw_fn(self, name, () /*llvm::CCallConv*/, return_type, params, variadic)
}
pub fn declare_global(&self, name: &str, ty: Type<'gcc>, global_kind: GlobalKind, is_tls: bool, link_section: Option<Symbol>) -> LValue<'gcc> {
let global = self.context.new_global(None, global_kind, ty, name);
if is_tls {
global.set_tls_model(self.tls_model);
}
if let Some(link_section) = link_section {
global.set_link_section(link_section.as_str());
}
let global_address = global.get_address(None);
self.globals.borrow_mut().insert(name.to_string(), global_address);
global
}
pub fn declare_private_global(&self, name: &str, ty: Type<'gcc>) -> LValue<'gcc> {
let global = self.context.new_global(None, GlobalKind::Internal, ty, name);
let global_address = global.get_address(None);
self.globals.borrow_mut().insert(name.to_string(), global_address);
global
}
pub fn declare_entry_fn(&self, name: &str, _fn_type: Type<'gcc>, callconv: () /*llvm::CCallConv*/) -> RValue<'gcc> {
// TODO(antoyo): use the fn_type parameter.
let const_string = self.context.new_type::<u8>().make_pointer().make_pointer();
let return_type = self.type_i32();
let variadic = false;
self.linkage.set(FunctionType::Exported);
let func = declare_raw_fn(self, name, callconv, return_type, &[self.type_i32(), const_string], variadic);
// NOTE: it is needed to set the current_func here as well, because get_fn() is not called
// for the main function.
*self.current_func.borrow_mut() = Some(func);
// FIXME(antoyo): this is a wrong cast. That requires changing the compiler API.
unsafe { std::mem::transmute(func) }
}
pub fn declare_fn(&self, name: &str, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> Function<'gcc> {
let FnAbiGcc {
return_type,
arguments_type,
is_c_variadic,
on_stack_param_indices,
#[cfg(feature="master")]
fn_attributes,
} = fn_abi.gcc_type(self);
let func = declare_raw_fn(self, name, () /*fn_abi.llvm_cconv()*/, return_type, &arguments_type, is_c_variadic);
self.on_stack_function_params.borrow_mut().insert(func, on_stack_param_indices);
#[cfg(feature="master")]
for fn_attr in fn_attributes {
func.add_attribute(fn_attr);
}
func
}
pub fn define_global(&self, name: &str, ty: Type<'gcc>, is_tls: bool, link_section: Option<Symbol>) -> LValue<'gcc> {
self.get_or_insert_global(name, ty, is_tls, link_section)
}
pub fn get_declared_value(&self, name: &str) -> Option<RValue<'gcc>> {
// TODO(antoyo): use a different field than globals, because this seems to return a function?
self.globals.borrow().get(name).cloned()
}
}
/// Declare a function.
///
/// If theres a value with the same name already declared, the function will
/// update the declaration and return existing Value instead.
fn declare_raw_fn<'gcc>(cx: &CodegenCx<'gcc, '_>, name: &str, _callconv: () /*llvm::CallConv*/, return_type: Type<'gcc>, param_types: &[Type<'gcc>], variadic: bool) -> Function<'gcc> {
if name.starts_with("llvm.") {
let intrinsic = llvm::intrinsic(name, cx);
cx.intrinsics.borrow_mut().insert(name.to_string(), intrinsic);
return intrinsic;
}
let func =
if cx.functions.borrow().contains_key(name) {
cx.functions.borrow()[name]
}
else {
let params: Vec<_> = param_types.into_iter().enumerate()
.map(|(index, param)| cx.context.new_parameter(None, *param, &format!("param{}", index))) // TODO(antoyo): set name.
.collect();
let func = cx.context.new_function(None, cx.linkage.get(), return_type, &params, mangle_name(name), variadic);
cx.functions.borrow_mut().insert(name.to_string(), func);
#[cfg(feature="master")]
if name == "rust_eh_personality" {
// NOTE: GCC will sometimes change the personality function set on a function from
// rust_eh_personality to __gcc_personality_v0 as an optimization.
// As such, we need to create a weak alias from __gcc_personality_v0 to
// rust_eh_personality in order to avoid a linker error.
// This needs to be weak in order to still allow using the standard
// __gcc_personality_v0 when the linking to it.
// Since aliases don't work (maybe because of a bug in LTO partitioning?), we
// create a wrapper function that calls rust_eh_personality.
let params: Vec<_> = param_types.into_iter().enumerate()
.map(|(index, param)| cx.context.new_parameter(None, *param, &format!("param{}", index))) // TODO(antoyo): set name.
.collect();
let gcc_func = cx.context.new_function(None, FunctionType::Exported, return_type, &params, "__gcc_personality_v0", variadic);
// We need a normal extern function for the crates that access rust_eh_personality
// without defining it, otherwise we'll get a compiler error.
//
// For the crate defining it, that needs to be a weak alias instead.
gcc_func.add_attribute(FnAttribute::Weak);
let block = gcc_func.new_block("start");
let mut args = vec![];
for param in &params {
args.push(param.to_rvalue());
}
let call = cx.context.new_call(None, func, &args);
if return_type == cx.type_void() {
block.add_eval(None, call);
block.end_with_void_return(None);
}
else {
block.end_with_return(None, call);
}
}
func
};
// TODO(antoyo): set function calling convention.
// TODO(antoyo): set unnamed address.
// TODO(antoyo): set no red zone function attribute.
// TODO(antoyo): set attributes for optimisation.
// TODO(antoyo): set attributes for non lazy bind.
// FIXME(antoyo): invalid cast.
func
}
// FIXME(antoyo): this is a hack because libgccjit currently only supports alpha, num and _.
// Unsupported characters: `$` and `.`.
pub fn mangle_name(name: &str) -> String {
name.replace(|char: char| {
if !char.is_alphanumeric() && char != '_' {
debug_assert!("$.*".contains(char), "Unsupported char in function name {}: {}", name, char);
true
}
else {
false
}
}, "_")
}