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94b46f34 | 1 | //! Code that is useful in various codegen modules. |
1a4d82fc | 2 | |
ba9703b0 XL |
3 | use crate::consts::{self, const_alloc_to_llvm}; |
4 | pub use crate::context::CodegenCx; | |
dfeec247 | 5 | use crate::llvm::{self, BasicBlock, Bool, ConstantInt, False, OperandBundleDef, True}; |
9fa01778 XL |
6 | use crate::type_::Type; |
7 | use crate::type_of::LayoutLlvmExt; | |
8 | use crate::value::Value; | |
54a0048b | 9 | |
3dfed10e | 10 | use rustc_ast::Mutability; |
ba9703b0 XL |
11 | use rustc_codegen_ssa::mir::place::PlaceRef; |
12 | use rustc_codegen_ssa::traits::*; | |
13 | use rustc_middle::bug; | |
14 | use rustc_middle::mir::interpret::{Allocation, GlobalAlloc, Scalar}; | |
29967ef6 | 15 | use rustc_middle::ty::{layout::TyAndLayout, ScalarInt}; |
dfeec247 | 16 | use rustc_span::symbol::Symbol; |
3dfed10e | 17 | use rustc_target::abi::{self, AddressSpace, HasDataLayout, LayoutOf, Pointer, Size}; |
1a4d82fc | 18 | |
ba9703b0 | 19 | use libc::{c_char, c_uint}; |
3dfed10e | 20 | use tracing::debug; |
1a4d82fc | 21 | |
1a4d82fc JJ |
22 | /* |
23 | * A note on nomenclature of linking: "extern", "foreign", and "upcall". | |
24 | * | |
25 | * An "extern" is an LLVM symbol we wind up emitting an undefined external | |
26 | * reference to. This means "we don't have the thing in this compilation unit, | |
27 | * please make sure you link it in at runtime". This could be a reference to | |
28 | * C code found in a C library, or rust code found in a rust crate. | |
29 | * | |
30 | * Most "externs" are implicitly declared (automatically) as a result of a | |
31 | * user declaring an extern _module_ dependency; this causes the rust driver | |
32 | * to locate an extern crate, scan its compilation metadata, and emit extern | |
33 | * declarations for any symbols used by the declaring crate. | |
34 | * | |
35 | * A "foreign" is an extern that references C (or other non-rust ABI) code. | |
36 | * There is no metadata to scan for extern references so in these cases either | |
37 | * a header-digester like bindgen, or manual function prototypes, have to | |
38 | * serve as declarators. So these are usually given explicitly as prototype | |
39 | * declarations, in rust code, with ABI attributes on them noting which ABI to | |
40 | * link via. | |
41 | * | |
42 | * An "upcall" is a foreign call generated by the compiler (not corresponding | |
43 | * to any user-written call in the code) into the runtime library, to perform | |
44 | * some helper task such as bringing a task to life, allocating memory, etc. | |
45 | * | |
46 | */ | |
47 | ||
7453a54e SL |
48 | /// A structure representing an active landing pad for the duration of a basic |
49 | /// block. | |
50 | /// | |
51 | /// Each `Block` may contain an instance of this, indicating whether the block | |
52 | /// is part of a landing pad or not. This is used to make decision about whether | |
0731742a | 53 | /// to emit `invoke` instructions (e.g., in a landing pad we don't continue to |
7453a54e SL |
54 | /// use `invoke`) and also about various function call metadata. |
55 | /// | |
56 | /// For GNU exceptions (`landingpad` + `resume` instructions) this structure is | |
57 | /// just a bunch of `None` instances (not too interesting), but for MSVC | |
58 | /// exceptions (`cleanuppad` + `cleanupret` instructions) this contains data. | |
59 | /// When inside of a landing pad, each function call in LLVM IR needs to be | |
60 | /// annotated with which landing pad it's a part of. This is accomplished via | |
61 | /// the `OperandBundleDef` value created for MSVC landing pads. | |
b7449926 XL |
62 | pub struct Funclet<'ll> { |
63 | cleanuppad: &'ll Value, | |
64 | operand: OperandBundleDef<'ll>, | |
7453a54e SL |
65 | } |
66 | ||
b7449926 XL |
67 | impl Funclet<'ll> { |
68 | pub fn new(cleanuppad: &'ll Value) -> Self { | |
dfeec247 | 69 | Funclet { cleanuppad, operand: OperandBundleDef::new("funclet", &[cleanuppad]) } |
7453a54e SL |
70 | } |
71 | ||
b7449926 | 72 | pub fn cleanuppad(&self) -> &'ll Value { |
3157f602 XL |
73 | self.cleanuppad |
74 | } | |
7453a54e | 75 | |
b7449926 | 76 | pub fn bundle(&self) -> &OperandBundleDef<'ll> { |
32a655c1 | 77 | &self.operand |
7453a54e | 78 | } |
1a4d82fc JJ |
79 | } |
80 | ||
a1dfa0c6 XL |
81 | impl BackendTypes for CodegenCx<'ll, 'tcx> { |
82 | type Value = &'ll Value; | |
29967ef6 | 83 | // FIXME(eddyb) replace this with a `Function` "subclass" of `Value`. |
e74abb32 XL |
84 | type Function = &'ll Value; |
85 | ||
a1dfa0c6 XL |
86 | type BasicBlock = &'ll BasicBlock; |
87 | type Type = &'ll Type; | |
88 | type Funclet = Funclet<'ll>; | |
1a4d82fc | 89 | |
a1dfa0c6 | 90 | type DIScope = &'ll llvm::debuginfo::DIScope; |
29967ef6 | 91 | type DILocation = &'ll llvm::debuginfo::DILocation; |
74b04a01 | 92 | type DIVariable = &'ll llvm::debuginfo::DIVariable; |
1a4d82fc JJ |
93 | } |
94 | ||
532ac7d7 | 95 | impl CodegenCx<'ll, 'tcx> { |
532ac7d7 | 96 | pub fn const_array(&self, ty: &'ll Type, elts: &[&'ll Value]) -> &'ll Value { |
ba9703b0 | 97 | unsafe { llvm::LLVMConstArray(ty, elts.as_ptr(), elts.len() as c_uint) } |
532ac7d7 XL |
98 | } |
99 | ||
100 | pub fn const_vector(&self, elts: &[&'ll Value]) -> &'ll Value { | |
ba9703b0 | 101 | unsafe { llvm::LLVMConstVector(elts.as_ptr(), elts.len() as c_uint) } |
532ac7d7 XL |
102 | } |
103 | ||
104 | pub fn const_bytes(&self, bytes: &[u8]) -> &'ll Value { | |
105 | bytes_in_context(self.llcx, bytes) | |
106 | } | |
107 | ||
dfeec247 | 108 | fn const_cstr(&self, s: Symbol, null_terminated: bool) -> &'ll Value { |
532ac7d7 XL |
109 | unsafe { |
110 | if let Some(&llval) = self.const_cstr_cache.borrow().get(&s) { | |
111 | return llval; | |
112 | } | |
113 | ||
e1599b0c | 114 | let s_str = s.as_str(); |
dfeec247 XL |
115 | let sc = llvm::LLVMConstStringInContext( |
116 | self.llcx, | |
117 | s_str.as_ptr() as *const c_char, | |
118 | s_str.len() as c_uint, | |
119 | !null_terminated as Bool, | |
120 | ); | |
532ac7d7 | 121 | let sym = self.generate_local_symbol_name("str"); |
dfeec247 | 122 | let g = self.define_global(&sym[..], self.val_ty(sc)).unwrap_or_else(|| { |
532ac7d7 XL |
123 | bug!("symbol `{}` is already defined", sym); |
124 | }); | |
125 | llvm::LLVMSetInitializer(g, sc); | |
126 | llvm::LLVMSetGlobalConstant(g, True); | |
127 | llvm::LLVMRustSetLinkage(g, llvm::Linkage::InternalLinkage); | |
128 | ||
129 | self.const_cstr_cache.borrow_mut().insert(s, g); | |
130 | g | |
131 | } | |
132 | } | |
133 | ||
532ac7d7 XL |
134 | pub fn const_get_elt(&self, v: &'ll Value, idx: u64) -> &'ll Value { |
135 | unsafe { | |
136 | assert_eq!(idx as c_uint as u64, idx); | |
137 | let us = &[idx as c_uint]; | |
138 | let r = llvm::LLVMConstExtractValue(v, us.as_ptr(), us.len() as c_uint); | |
139 | ||
dfeec247 | 140 | debug!("const_get_elt(v={:?}, idx={}, r={:?})", v, idx, r); |
532ac7d7 XL |
141 | |
142 | r | |
143 | } | |
144 | } | |
532ac7d7 XL |
145 | } |
146 | ||
a1dfa0c6 XL |
147 | impl ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> { |
148 | fn const_null(&self, t: &'ll Type) -> &'ll Value { | |
dfeec247 | 149 | unsafe { llvm::LLVMConstNull(t) } |
1a4d82fc | 150 | } |
1a4d82fc | 151 | |
a1dfa0c6 | 152 | fn const_undef(&self, t: &'ll Type) -> &'ll Value { |
dfeec247 | 153 | unsafe { llvm::LLVMGetUndef(t) } |
ea8adc8c | 154 | } |
ea8adc8c | 155 | |
a1dfa0c6 | 156 | fn const_int(&self, t: &'ll Type, i: i64) -> &'ll Value { |
dfeec247 | 157 | unsafe { llvm::LLVMConstInt(t, i as u64, True) } |
1a4d82fc | 158 | } |
1a4d82fc | 159 | |
a1dfa0c6 | 160 | fn const_uint(&self, t: &'ll Type, i: u64) -> &'ll Value { |
dfeec247 | 161 | unsafe { llvm::LLVMConstInt(t, i, False) } |
32a655c1 | 162 | } |
c34b1796 | 163 | |
a1dfa0c6 XL |
164 | fn const_uint_big(&self, t: &'ll Type, u: u128) -> &'ll Value { |
165 | unsafe { | |
166 | let words = [u as u64, (u >> 64) as u64]; | |
167 | llvm::LLVMConstIntOfArbitraryPrecision(t, 2, words.as_ptr()) | |
168 | } | |
169 | } | |
1a4d82fc | 170 | |
a1dfa0c6 XL |
171 | fn const_bool(&self, val: bool) -> &'ll Value { |
172 | self.const_uint(self.type_i1(), val as u64) | |
1a4d82fc JJ |
173 | } |
174 | ||
a1dfa0c6 XL |
175 | fn const_i32(&self, i: i32) -> &'ll Value { |
176 | self.const_int(self.type_i32(), i as i64) | |
177 | } | |
1a4d82fc | 178 | |
a1dfa0c6 XL |
179 | fn const_u32(&self, i: u32) -> &'ll Value { |
180 | self.const_uint(self.type_i32(), i as u64) | |
181 | } | |
1a4d82fc | 182 | |
a1dfa0c6 XL |
183 | fn const_u64(&self, i: u64) -> &'ll Value { |
184 | self.const_uint(self.type_i64(), i) | |
185 | } | |
1a4d82fc | 186 | |
a1dfa0c6 XL |
187 | fn const_usize(&self, i: u64) -> &'ll Value { |
188 | let bit_size = self.data_layout().pointer_size.bits(); | |
189 | if bit_size < 64 { | |
190 | // make sure it doesn't overflow | |
dfeec247 | 191 | assert!(i < (1 << bit_size)); |
1a4d82fc JJ |
192 | } |
193 | ||
a1dfa0c6 | 194 | self.const_uint(self.isize_ty, i) |
1a4d82fc | 195 | } |
1a4d82fc | 196 | |
a1dfa0c6 XL |
197 | fn const_u8(&self, i: u8) -> &'ll Value { |
198 | self.const_uint(self.type_i8(), i as u64) | |
199 | } | |
ff7c6d11 | 200 | |
416331ca XL |
201 | fn const_real(&self, t: &'ll Type, val: f64) -> &'ll Value { |
202 | unsafe { llvm::LLVMConstReal(t, val) } | |
203 | } | |
204 | ||
e74abb32 XL |
205 | fn const_str(&self, s: Symbol) -> (&'ll Value, &'ll Value) { |
206 | let len = s.as_str().len(); | |
dfeec247 XL |
207 | let cs = consts::ptrcast( |
208 | self.const_cstr(s, false), | |
f035d41b | 209 | self.type_ptr_to(self.layout_of(self.tcx.types.str_).llvm_type(self)), |
dfeec247 | 210 | ); |
e74abb32 XL |
211 | (cs, self.const_usize(len as u64)) |
212 | } | |
213 | ||
dfeec247 | 214 | fn const_struct(&self, elts: &[&'ll Value], packed: bool) -> &'ll Value { |
a1dfa0c6 | 215 | struct_in_context(self.llcx, elts, packed) |
85aaf69f | 216 | } |
85aaf69f | 217 | |
e74abb32 | 218 | fn const_to_opt_uint(&self, v: &'ll Value) -> Option<u64> { |
dfeec247 | 219 | try_as_const_integral(v).map(|v| unsafe { llvm::LLVMConstIntGetZExtValue(v) }) |
0531ce1d | 220 | } |
0531ce1d | 221 | |
a1dfa0c6 | 222 | fn const_to_opt_u128(&self, v: &'ll Value, sign_ext: bool) -> Option<u128> { |
e74abb32 XL |
223 | try_as_const_integral(v).and_then(|v| unsafe { |
224 | let (mut lo, mut hi) = (0u64, 0u64); | |
dfeec247 | 225 | let success = llvm::LLVMRustConstInt128Get(v, sign_ext, &mut hi, &mut lo); |
60c5eb7d | 226 | success.then_some(hi_lo_to_u128(lo, hi)) |
e74abb32 | 227 | }) |
c34b1796 | 228 | } |
c34b1796 | 229 | |
ba9703b0 | 230 | fn scalar_to_backend(&self, cv: Scalar, layout: &abi::Scalar, llty: &'ll Type) -> &'ll Value { |
a1dfa0c6 XL |
231 | let bitsize = if layout.is_bool() { 1 } else { layout.value.size(self).bits() }; |
232 | match cv { | |
29967ef6 | 233 | Scalar::Int(ScalarInt::ZST) => { |
a1dfa0c6 XL |
234 | assert_eq!(0, layout.value.size(self).bytes()); |
235 | self.const_undef(self.type_ix(0)) | |
dfeec247 | 236 | } |
29967ef6 XL |
237 | Scalar::Int(int) => { |
238 | let data = int.assert_bits(layout.value.size(self)); | |
dc9dc135 | 239 | let llval = self.const_uint_big(self.type_ix(bitsize), data); |
ba9703b0 | 240 | if layout.value == Pointer { |
a1dfa0c6 XL |
241 | unsafe { llvm::LLVMConstIntToPtr(llval, llty) } |
242 | } else { | |
243 | self.const_bitcast(llval, llty) | |
244 | } | |
dfeec247 | 245 | } |
136023e0 XL |
246 | Scalar::Ptr(ptr, _size) => { |
247 | let (alloc_id, offset) = ptr.into_parts(); | |
248 | let (base_addr, base_addr_space) = match self.tcx.global_alloc(alloc_id) { | |
f9f354fc | 249 | GlobalAlloc::Memory(alloc) => { |
a1dfa0c6 | 250 | let init = const_alloc_to_llvm(self, alloc); |
ba9703b0 XL |
251 | let value = match alloc.mutability { |
252 | Mutability::Mut => self.static_addr_of_mut(init, alloc.align, None), | |
253 | _ => self.static_addr_of(init, alloc.align, None), | |
254 | }; | |
255 | if !self.sess().fewer_names() { | |
136023e0 | 256 | llvm::set_value_name(value, format!("{:?}", alloc_id).as_bytes()); |
a1dfa0c6 | 257 | } |
3dfed10e | 258 | (value, AddressSpace::DATA) |
a1dfa0c6 | 259 | } |
3dfed10e XL |
260 | GlobalAlloc::Function(fn_instance) => ( |
261 | self.get_fn_addr(fn_instance.polymorphize(self.tcx)), | |
262 | self.data_layout().instruction_address_space, | |
263 | ), | |
f9f354fc | 264 | GlobalAlloc::Static(def_id) => { |
48663c56 | 265 | assert!(self.tcx.is_static(def_id)); |
f9f354fc | 266 | assert!(!self.tcx.is_thread_local_static(def_id)); |
3dfed10e | 267 | (self.get_static(def_id), AddressSpace::DATA) |
a1dfa0c6 | 268 | } |
a1dfa0c6 | 269 | }; |
dfeec247 | 270 | let llval = unsafe { |
94222f64 XL |
271 | llvm::LLVMRustConstInBoundsGEP2( |
272 | self.type_i8(), | |
3dfed10e | 273 | self.const_bitcast(base_addr, self.type_i8p_ext(base_addr_space)), |
136023e0 | 274 | &self.const_usize(offset.bytes()), |
dfeec247 XL |
275 | 1, |
276 | ) | |
277 | }; | |
ba9703b0 | 278 | if layout.value != Pointer { |
a1dfa0c6 XL |
279 | unsafe { llvm::LLVMConstPtrToInt(llval, llty) } |
280 | } else { | |
281 | self.const_bitcast(llval, llty) | |
282 | } | |
283 | } | |
1a4d82fc | 284 | } |
a1dfa0c6 | 285 | } |
e9174d1e | 286 | |
136023e0 XL |
287 | fn const_data_from_alloc(&self, alloc: &Allocation) -> Self::Value { |
288 | const_alloc_to_llvm(self, alloc) | |
289 | } | |
290 | ||
a1dfa0c6 XL |
291 | fn from_const_alloc( |
292 | &self, | |
ba9703b0 | 293 | layout: TyAndLayout<'tcx>, |
a1dfa0c6 XL |
294 | alloc: &Allocation, |
295 | offset: Size, | |
296 | ) -> PlaceRef<'tcx, &'ll Value> { | |
416331ca | 297 | assert_eq!(alloc.align, layout.align.abi); |
e1599b0c XL |
298 | let llty = self.type_ptr_to(layout.llvm_type(self)); |
299 | let llval = if layout.size == Size::ZERO { | |
300 | let llval = self.const_usize(alloc.align.bytes()); | |
301 | unsafe { llvm::LLVMConstIntToPtr(llval, llty) } | |
302 | } else { | |
303 | let init = const_alloc_to_llvm(self, alloc); | |
304 | let base_addr = self.static_addr_of(init, alloc.align, None); | |
305 | ||
dfeec247 | 306 | let llval = unsafe { |
94222f64 XL |
307 | llvm::LLVMRustConstInBoundsGEP2( |
308 | self.type_i8(), | |
dfeec247 XL |
309 | self.const_bitcast(base_addr, self.type_i8p()), |
310 | &self.const_usize(offset.bytes()), | |
311 | 1, | |
312 | ) | |
313 | }; | |
e1599b0c XL |
314 | self.const_bitcast(llval, llty) |
315 | }; | |
316 | PlaceRef::new_sized(llval, layout) | |
a1dfa0c6 | 317 | } |
92a42be0 | 318 | |
a1dfa0c6 XL |
319 | fn const_ptrcast(&self, val: &'ll Value, ty: &'ll Type) -> &'ll Value { |
320 | consts::ptrcast(val, ty) | |
92a42be0 SL |
321 | } |
322 | } | |
323 | ||
5869c6ff | 324 | /// Get the [LLVM type][Type] of a [`Value`]. |
ba9703b0 | 325 | pub fn val_ty(v: &Value) -> &Type { |
dfeec247 | 326 | unsafe { llvm::LLVMTypeOf(v) } |
92a42be0 SL |
327 | } |
328 | ||
a1dfa0c6 XL |
329 | pub fn bytes_in_context(llcx: &'ll llvm::Context, bytes: &[u8]) -> &'ll Value { |
330 | unsafe { | |
331 | let ptr = bytes.as_ptr() as *const c_char; | |
ba9703b0 | 332 | llvm::LLVMConstStringInContext(llcx, ptr, bytes.len() as c_uint, True) |
92a42be0 SL |
333 | } |
334 | } | |
476ff2be | 335 | |
dfeec247 | 336 | pub fn struct_in_context(llcx: &'a llvm::Context, elts: &[&'a Value], packed: bool) -> &'a Value { |
a1dfa0c6 | 337 | unsafe { |
dfeec247 | 338 | llvm::LLVMConstStructInContext(llcx, elts.as_ptr(), elts.len() as c_uint, packed as Bool) |
476ff2be SL |
339 | } |
340 | } | |
a1dfa0c6 XL |
341 | |
342 | #[inline] | |
343 | fn hi_lo_to_u128(lo: u64, hi: u64) -> u128 { | |
344 | ((hi as u128) << 64) | (lo as u128) | |
345 | } | |
e74abb32 | 346 | |
ba9703b0 | 347 | fn try_as_const_integral(v: &Value) -> Option<&ConstantInt> { |
dfeec247 | 348 | unsafe { llvm::LLVMIsAConstantInt(v) } |
e74abb32 | 349 | } |