1 use crate::builder::Builder;
2 use crate::context::CodegenCx;
3 use crate::llvm::{self, AttributePlace};
4 use crate::type_::Type;
5 use crate::type_of::LayoutLlvmExt;
6 use crate::value::Value;
8 use rustc_codegen_ssa::mir::operand::OperandValue;
9 use rustc_codegen_ssa::mir::place::PlaceRef;
10 use rustc_codegen_ssa::traits::*;
11 use rustc_codegen_ssa::MemFlags;
12 use rustc_middle::bug;
13 use rustc_middle::ty::layout::LayoutOf;
14 pub use rustc_middle::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
15 use rustc_middle::ty::Ty;
16 use rustc_target::abi::call::ArgAbi;
17 pub use rustc_target::abi::call::*;
18 use rustc_target::abi::{self, HasDataLayout, Int};
19 pub use rustc_target::spec::abi::Abi;
23 macro_rules! for_each_kind {
24 ($flags: ident, $f: ident, $($kind: ident),+) => ({
25 $(if $flags.contains(ArgAttribute::$kind) { $f(llvm::Attribute::$kind) })+
29 trait ArgAttributeExt {
30 fn for_each_kind<F>(&self, f: F)
32 F: FnMut(llvm::Attribute);
35 impl ArgAttributeExt for ArgAttribute {
36 fn for_each_kind<F>(&self, mut f: F)
38 F: FnMut(llvm::Attribute),
40 for_each_kind!(self, f, NoAlias, NoCapture, NonNull, ReadOnly, InReg)
44 pub trait ArgAttributesExt {
45 fn apply_attrs_to_llfn(&self, idx: AttributePlace, cx: &CodegenCx<'_, '_>, llfn: &Value);
46 fn apply_attrs_to_callsite(
49 cx: &CodegenCx<'_, '_>,
54 fn should_use_mutable_noalias(cx: &CodegenCx<'_, '_>) -> bool {
55 // LLVM prior to version 12 had known miscompiles in the presence of
56 // noalias attributes (see #54878), but we don't support earlier
57 // versions at all anymore. We now enable mutable noalias by default.
58 cx.tcx.sess.opts.debugging_opts.mutable_noalias.unwrap_or(true)
61 impl ArgAttributesExt for ArgAttributes {
62 fn apply_attrs_to_llfn(&self, idx: AttributePlace, cx: &CodegenCx<'_, '_>, llfn: &Value) {
63 let mut regular = self.regular;
65 let deref = self.pointee_size.bytes();
67 if regular.contains(ArgAttribute::NonNull) {
68 llvm::LLVMRustAddDereferenceableAttr(llfn, idx.as_uint(), deref);
70 llvm::LLVMRustAddDereferenceableOrNullAttr(llfn, idx.as_uint(), deref);
72 regular -= ArgAttribute::NonNull;
74 if let Some(align) = self.pointee_align {
75 llvm::LLVMRustAddAlignmentAttr(llfn, idx.as_uint(), align.bytes() as u32);
77 regular.for_each_kind(|attr| attr.apply_llfn(idx, llfn));
78 if regular.contains(ArgAttribute::NoAliasMutRef) && should_use_mutable_noalias(cx) {
79 llvm::Attribute::NoAlias.apply_llfn(idx, llfn);
82 ArgExtension::None => {}
83 ArgExtension::Zext => {
84 llvm::Attribute::ZExt.apply_llfn(idx, llfn);
86 ArgExtension::Sext => {
87 llvm::Attribute::SExt.apply_llfn(idx, llfn);
93 fn apply_attrs_to_callsite(
96 cx: &CodegenCx<'_, '_>,
99 let mut regular = self.regular;
101 let deref = self.pointee_size.bytes();
103 if regular.contains(ArgAttribute::NonNull) {
104 llvm::LLVMRustAddDereferenceableCallSiteAttr(callsite, idx.as_uint(), deref);
106 llvm::LLVMRustAddDereferenceableOrNullCallSiteAttr(
112 regular -= ArgAttribute::NonNull;
114 if let Some(align) = self.pointee_align {
115 llvm::LLVMRustAddAlignmentCallSiteAttr(
118 align.bytes() as u32,
121 regular.for_each_kind(|attr| attr.apply_callsite(idx, callsite));
122 if regular.contains(ArgAttribute::NoAliasMutRef) && should_use_mutable_noalias(cx) {
123 llvm::Attribute::NoAlias.apply_callsite(idx, callsite);
126 ArgExtension::None => {}
127 ArgExtension::Zext => {
128 llvm::Attribute::ZExt.apply_callsite(idx, callsite);
130 ArgExtension::Sext => {
131 llvm::Attribute::SExt.apply_callsite(idx, callsite);
139 fn llvm_type(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type;
142 impl LlvmType for Reg {
143 fn llvm_type(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type {
145 RegKind::Integer => cx.type_ix(self.size.bits()),
146 RegKind::Float => match self.size.bits() {
149 _ => bug!("unsupported float: {:?}", self),
151 RegKind::Vector => cx.type_vector(cx.type_i8(), self.size.bytes()),
156 impl LlvmType for CastTarget {
157 fn llvm_type(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type {
158 let rest_ll_unit = self.rest.unit.llvm_type(cx);
159 let (rest_count, rem_bytes) = if self.rest.unit.size.bytes() == 0 {
163 self.rest.total.bytes() / self.rest.unit.size.bytes(),
164 self.rest.total.bytes() % self.rest.unit.size.bytes(),
168 if self.prefix.iter().all(|x| x.is_none()) {
169 // Simplify to a single unit when there is no prefix and size <= unit size
170 if self.rest.total <= self.rest.unit.size {
174 // Simplify to array when all chunks are the same size and type
176 return cx.type_array(rest_ll_unit, rest_count);
180 // Create list of fields in the main structure
181 let mut args: Vec<_> = self
184 .flat_map(|option_kind| {
185 option_kind.map(|kind| Reg { kind, size: self.prefix_chunk_size }.llvm_type(cx))
187 .chain((0..rest_count).map(|_| rest_ll_unit))
190 // Append final integer
192 // Only integers can be really split further.
193 assert_eq!(self.rest.unit.kind, RegKind::Integer);
194 args.push(cx.type_ix(rem_bytes * 8));
197 cx.type_struct(&args, false)
201 pub trait ArgAbiExt<'ll, 'tcx> {
202 fn memory_ty(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
205 bx: &mut Builder<'_, 'll, 'tcx>,
207 dst: PlaceRef<'tcx, &'ll Value>,
211 bx: &mut Builder<'_, 'll, 'tcx>,
213 dst: PlaceRef<'tcx, &'ll Value>,
217 impl ArgAbiExt<'ll, 'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
218 /// Gets the LLVM type for a place of the original Rust type of
219 /// this argument/return, i.e., the result of `type_of::type_of`.
220 fn memory_ty(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
221 self.layout.llvm_type(cx)
224 /// Stores a direct/indirect value described by this ArgAbi into a
225 /// place for the original Rust type of this argument/return.
226 /// Can be used for both storing formal arguments into Rust variables
227 /// or results of call/invoke instructions into their destinations.
230 bx: &mut Builder<'_, 'll, 'tcx>,
232 dst: PlaceRef<'tcx, &'ll Value>,
234 if self.is_ignore() {
237 if self.is_sized_indirect() {
238 OperandValue::Ref(val, None, self.layout.align.abi).store(bx, dst)
239 } else if self.is_unsized_indirect() {
240 bug!("unsized `ArgAbi` must be handled through `store_fn_arg`");
241 } else if let PassMode::Cast(cast) = self.mode {
242 // FIXME(eddyb): Figure out when the simpler Store is safe, clang
243 // uses it for i16 -> {i8, i8}, but not for i24 -> {i8, i8, i8}.
244 let can_store_through_cast_ptr = false;
245 if can_store_through_cast_ptr {
246 let cast_ptr_llty = bx.type_ptr_to(cast.llvm_type(bx));
247 let cast_dst = bx.pointercast(dst.llval, cast_ptr_llty);
248 bx.store(val, cast_dst, self.layout.align.abi);
250 // The actual return type is a struct, but the ABI
251 // adaptation code has cast it into some scalar type. The
252 // code that follows is the only reliable way I have
253 // found to do a transform like i64 -> {i32,i32}.
254 // Basically we dump the data onto the stack then memcpy it.
256 // Other approaches I tried:
257 // - Casting rust ret pointer to the foreign type and using Store
258 // is (a) unsafe if size of foreign type > size of rust type and
259 // (b) runs afoul of strict aliasing rules, yielding invalid
260 // assembly under -O (specifically, the store gets removed).
261 // - Truncating foreign type to correct integral type and then
262 // bitcasting to the struct type yields invalid cast errors.
264 // We instead thus allocate some scratch space...
265 let scratch_size = cast.size(bx);
266 let scratch_align = cast.align(bx);
267 let llscratch = bx.alloca(cast.llvm_type(bx), scratch_align);
268 bx.lifetime_start(llscratch, scratch_size);
270 // ... where we first store the value...
271 bx.store(val, llscratch, scratch_align);
273 // ... and then memcpy it to the intended destination.
276 self.layout.align.abi,
279 bx.const_usize(self.layout.size.bytes()),
283 bx.lifetime_end(llscratch, scratch_size);
286 OperandValue::Immediate(val).store(bx, dst);
292 bx: &mut Builder<'a, 'll, 'tcx>,
294 dst: PlaceRef<'tcx, &'ll Value>,
297 let val = llvm::get_param(bx.llfn(), *idx as c_uint);
302 PassMode::Ignore => {}
303 PassMode::Pair(..) => {
304 OperandValue::Pair(next(), next()).store(bx, dst);
306 PassMode::Indirect { attrs: _, extra_attrs: Some(_), on_stack: _ } => {
307 OperandValue::Ref(next(), Some(next()), self.layout.align.abi).store(bx, dst);
310 | PassMode::Indirect { attrs: _, extra_attrs: None, on_stack: _ }
311 | PassMode::Cast(_) => {
312 let next_arg = next();
313 self.store(bx, next_arg, dst);
319 impl ArgAbiMethods<'tcx> for Builder<'a, 'll, 'tcx> {
322 arg_abi: &ArgAbi<'tcx, Ty<'tcx>>,
324 dst: PlaceRef<'tcx, Self::Value>,
326 arg_abi.store_fn_arg(self, idx, dst)
330 arg_abi: &ArgAbi<'tcx, Ty<'tcx>>,
332 dst: PlaceRef<'tcx, &'ll Value>,
334 arg_abi.store(self, val, dst)
336 fn arg_memory_ty(&self, arg_abi: &ArgAbi<'tcx, Ty<'tcx>>) -> &'ll Type {
337 arg_abi.memory_ty(self)
341 pub trait FnAbiLlvmExt<'tcx> {
342 fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
343 fn ptr_to_llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
344 fn llvm_cconv(&self) -> llvm::CallConv;
345 fn apply_attrs_llfn(&self, cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value);
346 fn apply_attrs_callsite(&self, bx: &mut Builder<'a, 'll, 'tcx>, callsite: &'ll Value);
349 impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
350 fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
351 // Ignore "extra" args from the call site for C variadic functions.
352 // Only the "fixed" args are part of the LLVM function signature.
353 let args = if self.c_variadic { &self.args[..self.fixed_count] } else { &self.args };
355 let args_capacity: usize = args.iter().map(|arg|
356 if arg.pad.is_some() { 1 } else { 0 } +
357 if let PassMode::Pair(_, _) = arg.mode { 2 } else { 1 }
359 let mut llargument_tys = Vec::with_capacity(
360 if let PassMode::Indirect { .. } = self.ret.mode { 1 } else { 0 } + args_capacity,
363 let llreturn_ty = match self.ret.mode {
364 PassMode::Ignore => cx.type_void(),
365 PassMode::Direct(_) | PassMode::Pair(..) => self.ret.layout.immediate_llvm_type(cx),
366 PassMode::Cast(cast) => cast.llvm_type(cx),
367 PassMode::Indirect { .. } => {
368 llargument_tys.push(cx.type_ptr_to(self.ret.memory_ty(cx)));
375 if let Some(ty) = arg.pad {
376 llargument_tys.push(ty.llvm_type(cx));
379 let llarg_ty = match arg.mode {
380 PassMode::Ignore => continue,
381 PassMode::Direct(_) => arg.layout.immediate_llvm_type(cx),
382 PassMode::Pair(..) => {
383 llargument_tys.push(arg.layout.scalar_pair_element_llvm_type(cx, 0, true));
384 llargument_tys.push(arg.layout.scalar_pair_element_llvm_type(cx, 1, true));
387 PassMode::Indirect { attrs: _, extra_attrs: Some(_), on_stack: _ } => {
388 let ptr_ty = cx.tcx.mk_mut_ptr(arg.layout.ty);
389 let ptr_layout = cx.layout_of(ptr_ty);
390 llargument_tys.push(ptr_layout.scalar_pair_element_llvm_type(cx, 0, true));
391 llargument_tys.push(ptr_layout.scalar_pair_element_llvm_type(cx, 1, true));
394 PassMode::Cast(cast) => cast.llvm_type(cx),
395 PassMode::Indirect { attrs: _, extra_attrs: None, on_stack: _ } => {
396 cx.type_ptr_to(arg.memory_ty(cx))
399 llargument_tys.push(llarg_ty);
403 cx.type_variadic_func(&llargument_tys, llreturn_ty)
405 cx.type_func(&llargument_tys, llreturn_ty)
409 fn ptr_to_llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
411 llvm::LLVMPointerType(
413 cx.data_layout().instruction_address_space.0 as c_uint,
418 fn llvm_cconv(&self) -> llvm::CallConv {
420 Conv::C | Conv::Rust | Conv::CCmseNonSecureCall => llvm::CCallConv,
421 Conv::AmdGpuKernel => llvm::AmdGpuKernel,
422 Conv::AvrInterrupt => llvm::AvrInterrupt,
423 Conv::AvrNonBlockingInterrupt => llvm::AvrNonBlockingInterrupt,
424 Conv::ArmAapcs => llvm::ArmAapcsCallConv,
425 Conv::Msp430Intr => llvm::Msp430Intr,
426 Conv::PtxKernel => llvm::PtxKernel,
427 Conv::X86Fastcall => llvm::X86FastcallCallConv,
428 Conv::X86Intr => llvm::X86_Intr,
429 Conv::X86Stdcall => llvm::X86StdcallCallConv,
430 Conv::X86ThisCall => llvm::X86_ThisCall,
431 Conv::X86VectorCall => llvm::X86_VectorCall,
432 Conv::X86_64SysV => llvm::X86_64_SysV,
433 Conv::X86_64Win64 => llvm::X86_64_Win64,
437 fn apply_attrs_llfn(&self, cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value) {
438 // FIXME(eddyb) can this also be applied to callsites?
439 if self.ret.layout.abi.is_uninhabited() {
440 llvm::Attribute::NoReturn.apply_llfn(llvm::AttributePlace::Function, llfn);
443 // FIXME(eddyb, wesleywiser): apply this to callsites as well?
444 if !self.can_unwind {
445 llvm::Attribute::NoUnwind.apply_llfn(llvm::AttributePlace::Function, llfn);
449 let mut apply = |attrs: &ArgAttributes| {
450 attrs.apply_attrs_to_llfn(llvm::AttributePlace::Argument(i), cx, llfn);
454 match self.ret.mode {
455 PassMode::Direct(ref attrs) => {
456 attrs.apply_attrs_to_llfn(llvm::AttributePlace::ReturnValue, cx, llfn);
458 PassMode::Indirect { ref attrs, extra_attrs: _, on_stack } => {
460 let i = apply(attrs);
462 llvm::LLVMRustAddStructRetAttr(
464 llvm::AttributePlace::Argument(i).as_uint(),
465 self.ret.layout.llvm_type(cx),
471 for arg in &self.args {
472 if arg.pad.is_some() {
473 apply(&ArgAttributes::new());
476 PassMode::Ignore => {}
477 PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: true } => {
478 let i = apply(attrs);
480 llvm::LLVMRustAddByValAttr(
482 llvm::AttributePlace::Argument(i).as_uint(),
483 arg.layout.llvm_type(cx),
487 PassMode::Direct(ref attrs)
488 | PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: false } => {
491 PassMode::Indirect { ref attrs, extra_attrs: Some(ref extra_attrs), on_stack } => {
496 PassMode::Pair(ref a, ref b) => {
500 PassMode::Cast(_) => {
501 apply(&ArgAttributes::new());
507 fn apply_attrs_callsite(&self, bx: &mut Builder<'a, 'll, 'tcx>, callsite: &'ll Value) {
508 if self.ret.layout.abi.is_uninhabited() {
509 llvm::Attribute::NoReturn.apply_callsite(llvm::AttributePlace::Function, callsite);
511 if !self.can_unwind {
512 llvm::Attribute::NoUnwind.apply_callsite(llvm::AttributePlace::Function, callsite);
516 let mut apply = |cx: &CodegenCx<'_, '_>, attrs: &ArgAttributes| {
517 attrs.apply_attrs_to_callsite(llvm::AttributePlace::Argument(i), cx, callsite);
521 match self.ret.mode {
522 PassMode::Direct(ref attrs) => {
523 attrs.apply_attrs_to_callsite(llvm::AttributePlace::ReturnValue, bx.cx, callsite);
525 PassMode::Indirect { ref attrs, extra_attrs: _, on_stack } => {
527 let i = apply(bx.cx, attrs);
529 llvm::LLVMRustAddStructRetCallSiteAttr(
531 llvm::AttributePlace::Argument(i).as_uint(),
532 self.ret.layout.llvm_type(bx),
538 if let abi::Abi::Scalar(scalar) = self.ret.layout.abi {
539 // If the value is a boolean, the range is 0..2 and that ultimately
540 // become 0..0 when the type becomes i1, which would be rejected
541 // by the LLVM verifier.
542 if let Int(..) = scalar.value {
543 if !scalar.is_bool() && !scalar.is_always_valid(bx) {
544 bx.range_metadata(callsite, scalar.valid_range);
548 for arg in &self.args {
549 if arg.pad.is_some() {
550 apply(bx.cx, &ArgAttributes::new());
553 PassMode::Ignore => {}
554 PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: true } => {
555 let i = apply(bx.cx, attrs);
557 llvm::LLVMRustAddByValCallSiteAttr(
559 llvm::AttributePlace::Argument(i).as_uint(),
560 arg.layout.llvm_type(bx),
564 PassMode::Direct(ref attrs)
565 | PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: false } => {
570 extra_attrs: Some(ref extra_attrs),
574 apply(bx.cx, extra_attrs);
576 PassMode::Pair(ref a, ref b) => {
580 PassMode::Cast(_) => {
581 apply(bx.cx, &ArgAttributes::new());
586 let cconv = self.llvm_cconv();
587 if cconv != llvm::CCallConv {
588 llvm::SetInstructionCallConv(callsite, cconv);
591 if self.conv == Conv::CCmseNonSecureCall {
592 // This will probably get ignored on all targets but those supporting the TrustZone-M
593 // extension (thumbv8m targets).
595 llvm::AddCallSiteAttrString(
597 llvm::AttributePlace::Function,
598 cstr::cstr!("cmse_nonsecure_call"),
605 impl AbiBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
606 fn apply_attrs_callsite(&mut self, fn_abi: &FnAbi<'tcx, Ty<'tcx>>, callsite: Self::Value) {
607 fn_abi.apply_attrs_callsite(self, callsite)
610 fn get_param(&self, index: usize) -> Self::Value {
611 llvm::get_param(self.llfn(), index as c_uint)