1 #![allow(non_camel_case_types, non_snake_case)]
3 //! Code that is useful in various codegen modules.
5 use crate::llvm::{self, True, False, Bool, BasicBlock, OperandBundleDef};
8 use crate::type_::Type;
9 use crate::type_of::LayoutLlvmExt;
10 use crate::value::Value;
11 use rustc_codegen_ssa::traits::*;
13 use crate::consts::const_alloc_to_llvm;
14 use rustc::ty::layout::{HasDataLayout, LayoutOf, self, TyLayout, Size};
15 use rustc::mir::interpret::{Scalar, GlobalAlloc, Allocation};
16 use rustc_codegen_ssa::mir::place::PlaceRef;
18 use libc::{c_uint, c_char};
20 use syntax::symbol::Symbol;
21 use syntax::ast::Mutability;
23 pub use crate::context::CodegenCx;
26 * A note on nomenclature of linking: "extern", "foreign", and "upcall".
28 * An "extern" is an LLVM symbol we wind up emitting an undefined external
29 * reference to. This means "we don't have the thing in this compilation unit,
30 * please make sure you link it in at runtime". This could be a reference to
31 * C code found in a C library, or rust code found in a rust crate.
33 * Most "externs" are implicitly declared (automatically) as a result of a
34 * user declaring an extern _module_ dependency; this causes the rust driver
35 * to locate an extern crate, scan its compilation metadata, and emit extern
36 * declarations for any symbols used by the declaring crate.
38 * A "foreign" is an extern that references C (or other non-rust ABI) code.
39 * There is no metadata to scan for extern references so in these cases either
40 * a header-digester like bindgen, or manual function prototypes, have to
41 * serve as declarators. So these are usually given explicitly as prototype
42 * declarations, in rust code, with ABI attributes on them noting which ABI to
45 * An "upcall" is a foreign call generated by the compiler (not corresponding
46 * to any user-written call in the code) into the runtime library, to perform
47 * some helper task such as bringing a task to life, allocating memory, etc.
51 /// A structure representing an active landing pad for the duration of a basic
54 /// Each `Block` may contain an instance of this, indicating whether the block
55 /// is part of a landing pad or not. This is used to make decision about whether
56 /// to emit `invoke` instructions (e.g., in a landing pad we don't continue to
57 /// use `invoke`) and also about various function call metadata.
59 /// For GNU exceptions (`landingpad` + `resume` instructions) this structure is
60 /// just a bunch of `None` instances (not too interesting), but for MSVC
61 /// exceptions (`cleanuppad` + `cleanupret` instructions) this contains data.
62 /// When inside of a landing pad, each function call in LLVM IR needs to be
63 /// annotated with which landing pad it's a part of. This is accomplished via
64 /// the `OperandBundleDef` value created for MSVC landing pads.
65 pub struct Funclet<'ll> {
66 cleanuppad: &'ll Value,
67 operand: OperandBundleDef<'ll>,
71 pub fn new(cleanuppad: &'ll Value) -> Self {
74 operand: OperandBundleDef::new("funclet", &[cleanuppad]),
78 pub fn cleanuppad(&self) -> &'ll Value {
82 pub fn bundle(&self) -> &OperandBundleDef<'ll> {
87 impl BackendTypes for CodegenCx<'ll, 'tcx> {
88 type Value = &'ll Value;
89 type BasicBlock = &'ll BasicBlock;
90 type Type = &'ll Type;
91 type Funclet = Funclet<'ll>;
93 type DIScope = &'ll llvm::debuginfo::DIScope;
96 impl CodegenCx<'ll, 'tcx> {
102 assert_eq!(abi::FAT_PTR_ADDR, 0);
103 assert_eq!(abi::FAT_PTR_EXTRA, 1);
104 self.const_struct(&[ptr, meta], false)
107 pub fn const_array(&self, ty: &'ll Type, elts: &[&'ll Value]) -> &'ll Value {
109 return llvm::LLVMConstArray(ty, elts.as_ptr(), elts.len() as c_uint);
113 pub fn const_vector(&self, elts: &[&'ll Value]) -> &'ll Value {
115 return llvm::LLVMConstVector(elts.as_ptr(), elts.len() as c_uint);
119 pub fn const_bytes(&self, bytes: &[u8]) -> &'ll Value {
120 bytes_in_context(self.llcx, bytes)
126 null_terminated: bool,
129 if let Some(&llval) = self.const_cstr_cache.borrow().get(&s) {
133 let s_str = s.as_str();
134 let sc = llvm::LLVMConstStringInContext(self.llcx,
135 s_str.as_ptr() as *const c_char,
136 s_str.len() as c_uint,
137 !null_terminated as Bool);
138 let sym = self.generate_local_symbol_name("str");
139 let g = self.define_global(&sym[..], self.val_ty(sc)).unwrap_or_else(||{
140 bug!("symbol `{}` is already defined", sym);
142 llvm::LLVMSetInitializer(g, sc);
143 llvm::LLVMSetGlobalConstant(g, True);
144 llvm::LLVMRustSetLinkage(g, llvm::Linkage::InternalLinkage);
146 self.const_cstr_cache.borrow_mut().insert(s, g);
151 pub fn const_str_slice(&self, s: Symbol) -> &'ll Value {
152 let len = s.as_str().len();
153 let cs = consts::ptrcast(self.const_cstr(s, false),
154 self.type_ptr_to(self.layout_of(self.tcx.mk_str()).llvm_type(self)));
155 self.const_fat_ptr(cs, self.const_usize(len as u64))
158 pub fn const_get_elt(&self, v: &'ll Value, idx: u64) -> &'ll Value {
160 assert_eq!(idx as c_uint as u64, idx);
161 let us = &[idx as c_uint];
162 let r = llvm::LLVMConstExtractValue(v, us.as_ptr(), us.len() as c_uint);
164 debug!("const_get_elt(v={:?}, idx={}, r={:?})",
172 impl ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
173 fn const_null(&self, t: &'ll Type) -> &'ll Value {
175 llvm::LLVMConstNull(t)
179 fn const_undef(&self, t: &'ll Type) -> &'ll Value {
181 llvm::LLVMGetUndef(t)
185 fn const_int(&self, t: &'ll Type, i: i64) -> &'ll Value {
187 llvm::LLVMConstInt(t, i as u64, True)
191 fn const_uint(&self, t: &'ll Type, i: u64) -> &'ll Value {
193 llvm::LLVMConstInt(t, i, False)
197 fn const_uint_big(&self, t: &'ll Type, u: u128) -> &'ll Value {
199 let words = [u as u64, (u >> 64) as u64];
200 llvm::LLVMConstIntOfArbitraryPrecision(t, 2, words.as_ptr())
204 fn const_bool(&self, val: bool) -> &'ll Value {
205 self.const_uint(self.type_i1(), val as u64)
208 fn const_i32(&self, i: i32) -> &'ll Value {
209 self.const_int(self.type_i32(), i as i64)
212 fn const_u32(&self, i: u32) -> &'ll Value {
213 self.const_uint(self.type_i32(), i as u64)
216 fn const_u64(&self, i: u64) -> &'ll Value {
217 self.const_uint(self.type_i64(), i)
220 fn const_usize(&self, i: u64) -> &'ll Value {
221 let bit_size = self.data_layout().pointer_size.bits();
223 // make sure it doesn't overflow
224 assert!(i < (1<<bit_size));
227 self.const_uint(self.isize_ty, i)
230 fn const_u8(&self, i: u8) -> &'ll Value {
231 self.const_uint(self.type_i8(), i as u64)
234 fn const_real(&self, t: &'ll Type, val: f64) -> &'ll Value {
235 unsafe { llvm::LLVMConstReal(t, val) }
243 struct_in_context(self.llcx, elts, packed)
246 fn const_to_uint(&self, v: &'ll Value) -> u64 {
248 llvm::LLVMConstIntGetZExtValue(v)
252 fn is_const_integral(&self, v: &'ll Value) -> bool {
254 llvm::LLVMIsAConstantInt(v).is_some()
258 fn const_to_opt_u128(&self, v: &'ll Value, sign_ext: bool) -> Option<u128> {
260 if self.is_const_integral(v) {
261 let (mut lo, mut hi) = (0u64, 0u64);
262 let success = llvm::LLVMRustConstInt128Get(v, sign_ext,
265 Some(hi_lo_to_u128(lo, hi))
275 fn scalar_to_backend(
278 layout: &layout::Scalar,
281 let bitsize = if layout.is_bool() { 1 } else { layout.value.size(self).bits() };
283 Scalar::Raw { size: 0, .. } => {
284 assert_eq!(0, layout.value.size(self).bytes());
285 self.const_undef(self.type_ix(0))
287 Scalar::Raw { data, size } => {
288 assert_eq!(size as u64, layout.value.size(self).bytes());
289 let llval = self.const_uint_big(self.type_ix(bitsize), data);
290 if layout.value == layout::Pointer {
291 unsafe { llvm::LLVMConstIntToPtr(llval, llty) }
293 self.const_bitcast(llval, llty)
296 Scalar::Ptr(ptr) => {
297 let alloc_kind = self.tcx.alloc_map.lock().get(ptr.alloc_id);
298 let base_addr = match alloc_kind {
299 Some(GlobalAlloc::Memory(alloc)) => {
300 let init = const_alloc_to_llvm(self, alloc);
301 if alloc.mutability == Mutability::Mutable {
302 self.static_addr_of_mut(init, alloc.align, None)
304 self.static_addr_of(init, alloc.align, None)
307 Some(GlobalAlloc::Function(fn_instance)) => {
308 self.get_fn(fn_instance)
310 Some(GlobalAlloc::Static(def_id)) => {
311 assert!(self.tcx.is_static(def_id));
312 self.get_static(def_id)
314 None => bug!("missing allocation {:?}", ptr.alloc_id),
316 let llval = unsafe { llvm::LLVMConstInBoundsGEP(
317 self.const_bitcast(base_addr, self.type_i8p()),
318 &self.const_usize(ptr.offset.bytes()),
321 if layout.value != layout::Pointer {
322 unsafe { llvm::LLVMConstPtrToInt(llval, llty) }
324 self.const_bitcast(llval, llty)
332 layout: TyLayout<'tcx>,
335 ) -> PlaceRef<'tcx, &'ll Value> {
336 assert_eq!(alloc.align, layout.align.abi);
337 let llty = self.type_ptr_to(layout.llvm_type(self));
338 let llval = if layout.size == Size::ZERO {
339 let llval = self.const_usize(alloc.align.bytes());
340 unsafe { llvm::LLVMConstIntToPtr(llval, llty) }
342 let init = const_alloc_to_llvm(self, alloc);
343 let base_addr = self.static_addr_of(init, alloc.align, None);
345 let llval = unsafe { llvm::LLVMConstInBoundsGEP(
346 self.const_bitcast(base_addr, self.type_i8p()),
347 &self.const_usize(offset.bytes()),
350 self.const_bitcast(llval, llty)
352 PlaceRef::new_sized(llval, layout, alloc.align)
355 fn const_ptrcast(&self, val: &'ll Value, ty: &'ll Type) -> &'ll Value {
356 consts::ptrcast(val, ty)
360 pub fn val_ty(v: &'ll Value) -> &'ll Type {
366 pub fn bytes_in_context(llcx: &'ll llvm::Context, bytes: &[u8]) -> &'ll Value {
368 let ptr = bytes.as_ptr() as *const c_char;
369 return llvm::LLVMConstStringInContext(llcx, ptr, bytes.len() as c_uint, True);
373 pub fn struct_in_context(
374 llcx: &'a llvm::Context,
379 llvm::LLVMConstStructInContext(llcx,
380 elts.as_ptr(), elts.len() as c_uint,
386 fn hi_lo_to_u128(lo: u64, hi: u64) -> u128 {
387 ((hi as u128) << 64) | (lo as u128)