1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
10 //! Declare various LLVM values.
12 //! Prefer using functions and methods from this module rather than calling LLVM
13 //! functions directly. These functions do some additional work to ensure we do
14 //! the right thing given the preconceptions of trans.
16 //! Some useful guidelines:
18 //! * Use declare_* family of methods if you are declaring, but are not
19 //! interested in defining the ValueRef they return.
20 //! * Use define_* family of methods when you might be defining the ValueRef.
21 //! * When in doubt, define.
23 use llvm::{self, ValueRef};
24 use llvm::AttributePlace::Function;
26 use rustc::session::config::Sanitizer;
27 use rustc_back::PanicStrategy;
28 use abi::{Abi, FnType};
30 use context::CrateContext;
35 use std::ffi::CString;
38 /// Declare a global value.
40 /// If there’s a value with the same name already declared, the function will
41 /// return its ValueRef instead.
42 pub fn declare_global(ccx: &CrateContext, name: &str, ty: Type) -> llvm::ValueRef {
43 debug!("declare_global(name={:?})", name);
44 let namebuf = CString::new(name).unwrap_or_else(|_|{
45 bug!("name {:?} contains an interior null byte", name)
48 llvm::LLVMRustGetOrInsertGlobal(ccx.llmod(), namebuf.as_ptr(), ty.to_ref())
53 /// Declare a function.
55 /// If there’s a value with the same name already declared, the function will
56 /// update the declaration and return existing ValueRef instead.
57 fn declare_raw_fn(ccx: &CrateContext, name: &str, callconv: llvm::CallConv, ty: Type) -> ValueRef {
58 debug!("declare_raw_fn(name={:?}, ty={:?})", name, ty);
59 let namebuf = CString::new(name).unwrap_or_else(|_|{
60 bug!("name {:?} contains an interior null byte", name)
63 llvm::LLVMRustGetOrInsertFunction(ccx.llmod(), namebuf.as_ptr(), ty.to_ref())
66 llvm::SetFunctionCallConv(llfn, callconv);
67 // Function addresses in Rust are never significant, allowing functions to
69 llvm::SetUnnamedAddr(llfn, true);
71 if ccx.tcx().sess.opts.cg.no_redzone
72 .unwrap_or(ccx.tcx().sess.target.target.options.disable_redzone) {
73 llvm::Attribute::NoRedZone.apply_llfn(Function, llfn);
76 if let Some(ref sanitizer) = ccx.tcx().sess.opts.debugging_opts.sanitizer {
78 Sanitizer::Address => {
79 llvm::Attribute::SanitizeAddress.apply_llfn(Function, llfn);
81 Sanitizer::Memory => {
82 llvm::Attribute::SanitizeMemory.apply_llfn(Function, llfn);
84 Sanitizer::Thread => {
85 llvm::Attribute::SanitizeThread.apply_llfn(Function, llfn);
91 match ccx.tcx().sess.opts.cg.opt_level.as_ref().map(String::as_ref) {
93 llvm::Attribute::OptimizeForSize.apply_llfn(Function, llfn);
96 llvm::Attribute::MinSize.apply_llfn(Function, llfn);
97 llvm::Attribute::OptimizeForSize.apply_llfn(Function, llfn);
102 if ccx.tcx().sess.panic_strategy() != PanicStrategy::Unwind {
103 attributes::unwind(llfn, false);
110 /// Declare a C ABI function.
112 /// Only use this for foreign function ABIs and glue. For Rust functions use
113 /// `declare_fn` instead.
115 /// If there’s a value with the same name already declared, the function will
116 /// update the declaration and return existing ValueRef instead.
117 pub fn declare_cfn(ccx: &CrateContext, name: &str, fn_type: Type) -> ValueRef {
118 declare_raw_fn(ccx, name, llvm::CCallConv, fn_type)
122 /// Declare a Rust function.
124 /// If there’s a value with the same name already declared, the function will
125 /// update the declaration and return existing ValueRef instead.
126 pub fn declare_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, name: &str,
127 fn_type: Ty<'tcx>) -> ValueRef {
128 debug!("declare_rust_fn(name={:?}, fn_type={:?})", name, fn_type);
129 let sig = common::ty_fn_sig(ccx, fn_type);
130 let sig = ccx.tcx().erase_late_bound_regions_and_normalize(&sig);
131 debug!("declare_rust_fn (after region erasure) sig={:?}", sig);
133 let fty = FnType::new(ccx, sig, &[]);
134 let llfn = declare_raw_fn(ccx, name, fty.cconv, fty.llvm_type(ccx));
136 // FIXME(canndrew): This is_never should really be an is_uninhabited
137 if sig.output().is_never() {
138 llvm::Attribute::NoReturn.apply_llfn(Function, llfn);
141 if sig.abi != Abi::Rust && sig.abi != Abi::RustCall {
142 attributes::unwind(llfn, false);
145 fty.apply_attrs_llfn(llfn);
151 /// Declare a global with an intention to define it.
153 /// Use this function when you intend to define a global. This function will
154 /// return None if the name already has a definition associated with it. In that
155 /// case an error should be reported to the user, because it usually happens due
156 /// to user’s fault (e.g. misuse of #[no_mangle] or #[export_name] attributes).
157 pub fn define_global(ccx: &CrateContext, name: &str, ty: Type) -> Option<ValueRef> {
158 if get_defined_value(ccx, name).is_some() {
161 Some(declare_global(ccx, name, ty))
165 /// Declare a Rust function with an intention to define it.
167 /// Use this function when you intend to define a function. This function will
168 /// return panic if the name already has a definition associated with it. This
169 /// can happen with #[no_mangle] or #[export_name], for example.
170 pub fn define_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
172 fn_type: Ty<'tcx>) -> ValueRef {
173 if get_defined_value(ccx, name).is_some() {
174 ccx.sess().fatal(&format!("symbol `{}` already defined", name))
176 declare_fn(ccx, name, fn_type)
180 /// Declare a Rust function with an intention to define it.
182 /// Use this function when you intend to define a function. This function will
183 /// return panic if the name already has a definition associated with it. This
184 /// can happen with #[no_mangle] or #[export_name], for example.
185 pub fn define_internal_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
187 fn_type: Ty<'tcx>) -> ValueRef {
188 let llfn = define_fn(ccx, name, fn_type);
189 unsafe { llvm::LLVMRustSetLinkage(llfn, llvm::Linkage::InternalLinkage) };
194 /// Get declared value by name.
195 pub fn get_declared_value(ccx: &CrateContext, name: &str) -> Option<ValueRef> {
196 debug!("get_declared_value(name={:?})", name);
197 let namebuf = CString::new(name).unwrap_or_else(|_|{
198 bug!("name {:?} contains an interior null byte", name)
200 let val = unsafe { llvm::LLVMRustGetNamedValue(ccx.llmod(), namebuf.as_ptr()) };
202 debug!("get_declared_value: {:?} value is null", name);
205 debug!("get_declared_value: {:?} => {:?}", name, Value(val));
210 /// Get defined or externally defined (AvailableExternally linkage) value by
212 pub fn get_defined_value(ccx: &CrateContext, name: &str) -> Option<ValueRef> {
213 get_declared_value(ccx, name).and_then(|val|{
214 let declaration = unsafe {
215 llvm::LLVMIsDeclaration(val) != 0