260 lines
10 KiB
Rust
260 lines
10 KiB
Rust
// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
|
||
// file at the top-level directory of this distribution and at
|
||
// http://rust-lang.org/COPYRIGHT.
|
||
//
|
||
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
||
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
||
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
||
// option. This file may not be copied, modified, or distributed
|
||
// except according to those terms.
|
||
//! Declare various LLVM values.
|
||
//!
|
||
//! Prefer using functions and methods from this module rather than calling LLVM
|
||
//! functions directly. These functions do some additional work to ensure we do
|
||
//! the right thing given the preconceptions of trans.
|
||
//!
|
||
//! Some useful guidelines:
|
||
//!
|
||
//! * Use declare_* family of methods if you are declaring, but are not
|
||
//! interested in defining the ValueRef they return.
|
||
//! * Use define_* family of methods when you might be defining the ValueRef.
|
||
//! * When in doubt, define.
|
||
use llvm::{self, ValueRef};
|
||
use middle::ty;
|
||
use middle::infer;
|
||
use syntax::abi;
|
||
use trans::attributes;
|
||
use trans::base;
|
||
use trans::context::CrateContext;
|
||
use trans::type_::Type;
|
||
use trans::type_of;
|
||
|
||
use std::ffi::CString;
|
||
use libc::c_uint;
|
||
|
||
|
||
/// Declare a global value.
|
||
///
|
||
/// If there’s a value with the same name already declared, the function will
|
||
/// return its ValueRef instead.
|
||
pub fn declare_global(ccx: &CrateContext, name: &str, ty: Type) -> llvm::ValueRef {
|
||
debug!("declare_global(name={:?})", name);
|
||
let namebuf = CString::new(name).unwrap_or_else(|_|{
|
||
ccx.sess().bug(&format!("name {:?} contains an interior null byte", name))
|
||
});
|
||
unsafe {
|
||
llvm::LLVMGetOrInsertGlobal(ccx.llmod(), namebuf.as_ptr(), ty.to_ref())
|
||
}
|
||
}
|
||
|
||
|
||
/// Declare a function.
|
||
///
|
||
/// For rust functions use `declare_rust_fn` instead.
|
||
///
|
||
/// If there’s a value with the same name already declared, the function will
|
||
/// update the declaration and return existing ValueRef instead.
|
||
pub fn declare_fn(ccx: &CrateContext, name: &str, callconv: llvm::CallConv,
|
||
ty: Type, output: ty::FnOutput) -> ValueRef {
|
||
debug!("declare_fn(name={:?})", name);
|
||
let namebuf = CString::new(name).unwrap_or_else(|_|{
|
||
ccx.sess().bug(&format!("name {:?} contains an interior null byte", name))
|
||
});
|
||
let llfn = unsafe {
|
||
llvm::LLVMGetOrInsertFunction(ccx.llmod(), namebuf.as_ptr(), ty.to_ref())
|
||
};
|
||
|
||
llvm::SetFunctionCallConv(llfn, callconv);
|
||
// Function addresses in Rust are never significant, allowing functions to
|
||
// be merged.
|
||
llvm::SetUnnamedAddr(llfn, true);
|
||
|
||
if output == ty::FnDiverging {
|
||
llvm::SetFunctionAttribute(llfn, llvm::Attribute::NoReturn);
|
||
}
|
||
|
||
if ccx.tcx().sess.opts.cg.no_redzone
|
||
.unwrap_or(ccx.tcx().sess.target.target.options.disable_redzone) {
|
||
llvm::SetFunctionAttribute(llfn, llvm::Attribute::NoRedZone)
|
||
}
|
||
|
||
llfn
|
||
}
|
||
|
||
|
||
/// Declare a C ABI function.
|
||
///
|
||
/// Only use this for foreign function ABIs and glue. For Rust functions use
|
||
/// `declare_rust_fn` instead.
|
||
///
|
||
/// If there’s a value with the same name already declared, the function will
|
||
/// update the declaration and return existing ValueRef instead.
|
||
pub fn declare_cfn(ccx: &CrateContext, name: &str, fn_type: Type,
|
||
output: ty::Ty) -> ValueRef {
|
||
declare_fn(ccx, name, llvm::CCallConv, fn_type, ty::FnConverging(output))
|
||
}
|
||
|
||
|
||
/// Declare a Rust function.
|
||
///
|
||
/// If there’s a value with the same name already declared, the function will
|
||
/// update the declaration and return existing ValueRef instead.
|
||
pub fn declare_rust_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, name: &str,
|
||
fn_type: ty::Ty<'tcx>) -> ValueRef {
|
||
debug!("declare_rust_fn(name={:?}, fn_type={:?})", name,
|
||
fn_type);
|
||
|
||
let function_type; // placeholder so that the memory ownership works out ok
|
||
let (sig, abi, env) = match fn_type.sty {
|
||
ty::TyBareFn(_, ref f) => {
|
||
(&f.sig, f.abi, None)
|
||
}
|
||
ty::TyClosure(closure_did, ref substs) => {
|
||
let infcx = infer::normalizing_infer_ctxt(ccx.tcx(), &ccx.tcx().tables);
|
||
function_type = infcx.closure_type(closure_did, substs);
|
||
let self_type = base::self_type_for_closure(ccx, closure_did, fn_type);
|
||
let llenvironment_type = type_of::type_of_explicit_arg(ccx, self_type);
|
||
debug!("declare_rust_fn function_type={:?} self_type={:?}",
|
||
function_type, self_type);
|
||
(&function_type.sig, abi::RustCall, Some(llenvironment_type))
|
||
}
|
||
_ => ccx.sess().bug("expected closure or fn")
|
||
};
|
||
|
||
let sig = ccx.tcx().erase_late_bound_regions(sig);
|
||
let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
|
||
debug!("declare_rust_fn (after region erasure) sig={:?}", sig);
|
||
let llfty = type_of::type_of_rust_fn(ccx, env, &sig, abi);
|
||
debug!("declare_rust_fn llfty={}", ccx.tn().type_to_string(llfty));
|
||
|
||
// it is ok to directly access sig.0.output because we erased all
|
||
// late-bound-regions above
|
||
let llfn = declare_fn(ccx, name, llvm::CCallConv, llfty, sig.output);
|
||
attributes::from_fn_type(ccx, fn_type).apply_llfn(llfn);
|
||
llfn
|
||
}
|
||
|
||
|
||
/// Declare a Rust function with internal linkage.
|
||
///
|
||
/// If there’s a value with the same name already declared, the function will
|
||
/// update the declaration and return existing ValueRef instead.
|
||
pub fn declare_internal_rust_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, name: &str,
|
||
fn_type: ty::Ty<'tcx>) -> ValueRef {
|
||
let llfn = declare_rust_fn(ccx, name, fn_type);
|
||
llvm::SetLinkage(llfn, llvm::InternalLinkage);
|
||
llfn
|
||
}
|
||
|
||
|
||
/// Declare a global with an intention to define it.
|
||
///
|
||
/// Use this function when you intend to define a global. This function will
|
||
/// return None if the name already has a definition associated with it. In that
|
||
/// case an error should be reported to the user, because it usually happens due
|
||
/// to user’s fault (e.g. misuse of #[no_mangle] or #[export_name] attributes).
|
||
pub fn define_global(ccx: &CrateContext, name: &str, ty: Type) -> Option<ValueRef> {
|
||
if get_defined_value(ccx, name).is_some() {
|
||
None
|
||
} else {
|
||
Some(declare_global(ccx, name, ty))
|
||
}
|
||
}
|
||
|
||
|
||
/// Declare a function with an intention to define it.
|
||
///
|
||
/// For rust functions use `define_rust_fn` instead.
|
||
///
|
||
/// Use this function when you intend to define a function. This function will
|
||
/// return None if the name already has a definition associated with it. In that
|
||
/// case an error should be reported to the user, because it usually happens due
|
||
/// to user’s fault (e.g. misuse of #[no_mangle] or #[export_name] attributes).
|
||
pub fn define_fn(ccx: &CrateContext, name: &str, callconv: llvm::CallConv,
|
||
fn_type: Type, output: ty::FnOutput) -> Option<ValueRef> {
|
||
if get_defined_value(ccx, name).is_some() {
|
||
None
|
||
} else {
|
||
Some(declare_fn(ccx, name, callconv, fn_type, output))
|
||
}
|
||
}
|
||
|
||
|
||
/// Declare a C ABI function with an intention to define it.
|
||
///
|
||
/// Use this function when you intend to define a function. This function will
|
||
/// return None if the name already has a definition associated with it. In that
|
||
/// case an error should be reported to the user, because it usually happens due
|
||
/// to user’s fault (e.g. misuse of #[no_mangle] or #[export_name] attributes).
|
||
///
|
||
/// Only use this for foreign function ABIs and glue. For Rust functions use
|
||
/// `declare_rust_fn` instead.
|
||
pub fn define_cfn(ccx: &CrateContext, name: &str, fn_type: Type,
|
||
output: ty::Ty) -> Option<ValueRef> {
|
||
if get_defined_value(ccx, name).is_some() {
|
||
None
|
||
} else {
|
||
Some(declare_cfn(ccx, name, fn_type, output))
|
||
}
|
||
}
|
||
|
||
|
||
/// Declare a Rust function with an intention to define it.
|
||
///
|
||
/// Use this function when you intend to define a function. This function will
|
||
/// return None if the name already has a definition associated with it. In that
|
||
/// case an error should be reported to the user, because it usually happens due
|
||
/// to user’s fault (e.g. misuse of #[no_mangle] or #[export_name] attributes).
|
||
pub fn define_rust_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, name: &str,
|
||
fn_type: ty::Ty<'tcx>) -> Option<ValueRef> {
|
||
if get_defined_value(ccx, name).is_some() {
|
||
None
|
||
} else {
|
||
Some(declare_rust_fn(ccx, name, fn_type))
|
||
}
|
||
}
|
||
|
||
|
||
/// Declare a Rust function with an intention to define it.
|
||
///
|
||
/// Use this function when you intend to define a function. This function will
|
||
/// return panic if the name already has a definition associated with it. This
|
||
/// can happen with #[no_mangle] or #[export_name], for example.
|
||
pub fn define_internal_rust_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
|
||
name: &str,
|
||
fn_type: ty::Ty<'tcx>) -> ValueRef {
|
||
if get_defined_value(ccx, name).is_some() {
|
||
ccx.sess().fatal(&format!("symbol `{}` already defined", name))
|
||
} else {
|
||
declare_internal_rust_fn(ccx, name, fn_type)
|
||
}
|
||
}
|
||
|
||
|
||
/// Get defined or externally defined (AvailableExternally linkage) value by
|
||
/// name.
|
||
fn get_defined_value(ccx: &CrateContext, name: &str) -> Option<ValueRef> {
|
||
debug!("get_defined_value(name={:?})", name);
|
||
let namebuf = CString::new(name).unwrap_or_else(|_|{
|
||
ccx.sess().bug(&format!("name {:?} contains an interior null byte", name))
|
||
});
|
||
let val = unsafe { llvm::LLVMGetNamedValue(ccx.llmod(), namebuf.as_ptr()) };
|
||
if val.is_null() {
|
||
debug!("get_defined_value: {:?} value is null", name);
|
||
None
|
||
} else {
|
||
let (declaration, aext_link) = unsafe {
|
||
let linkage = llvm::LLVMGetLinkage(val);
|
||
(llvm::LLVMIsDeclaration(val) != 0,
|
||
linkage == llvm::AvailableExternallyLinkage as c_uint)
|
||
};
|
||
debug!("get_defined_value: found {:?} value (declaration: {}, \
|
||
aext_link: {})", name, declaration, aext_link);
|
||
if !declaration || aext_link {
|
||
Some(val)
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
}
|