diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/abi.rs | 120 | ||||
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/intrinsic.rs | 2 |
2 files changed, 52 insertions, 70 deletions
diff --git a/compiler/rustc_codegen_llvm/src/abi.rs b/compiler/rustc_codegen_llvm/src/abi.rs index e5f5146fac8..d2828669d43 100644 --- a/compiler/rustc_codegen_llvm/src/abi.rs +++ b/compiler/rustc_codegen_llvm/src/abi.rs @@ -16,13 +16,15 @@ pub use rustc_middle::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA}; use rustc_middle::ty::Ty; use rustc_session::config; pub use rustc_target::abi::call::*; -use rustc_target::abi::{self, HasDataLayout, Int}; +use rustc_target::abi::{self, HasDataLayout, Int, Size}; pub use rustc_target::spec::abi::Abi; use rustc_target::spec::SanitizerSet; use libc::c_uint; use smallvec::SmallVec; +use std::cmp; + pub trait ArgAttributesExt { fn apply_attrs_to_llfn(&self, idx: AttributePlace, cx: &CodegenCx<'_, '_>, llfn: &Value); fn apply_attrs_to_callsite( @@ -130,42 +132,36 @@ impl LlvmType for Reg { impl LlvmType for CastTarget { fn llvm_type<'ll>(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type { let rest_ll_unit = self.rest.unit.llvm_type(cx); - let (rest_count, rem_bytes) = if self.rest.unit.size.bytes() == 0 { - (0, 0) + let rest_count = if self.rest.total == Size::ZERO { + 0 } else { - ( - self.rest.total.bytes() / self.rest.unit.size.bytes(), - self.rest.total.bytes() % self.rest.unit.size.bytes(), - ) + assert_ne!( + self.rest.unit.size, + Size::ZERO, + "total size {:?} cannot be divided into units of zero size", + self.rest.total + ); + if self.rest.total.bytes() % self.rest.unit.size.bytes() != 0 { + assert_eq!(self.rest.unit.kind, RegKind::Integer, "only int regs can be split"); + } + self.rest.total.bytes().div_ceil(self.rest.unit.size.bytes()) }; + // Simplify to a single unit or an array if there's no prefix. + // This produces the same layout, but using a simpler type. if self.prefix.iter().all(|x| x.is_none()) { - // Simplify to a single unit when there is no prefix and size <= unit size - if self.rest.total <= self.rest.unit.size { + if rest_count == 1 { return rest_ll_unit; } - // Simplify to array when all chunks are the same size and type - if rem_bytes == 0 { - return cx.type_array(rest_ll_unit, rest_count); - } - } - - // Create list of fields in the main structure - let mut args: Vec<_> = self - .prefix - .iter() - .flat_map(|option_reg| option_reg.map(|reg| reg.llvm_type(cx))) - .chain((0..rest_count).map(|_| rest_ll_unit)) - .collect(); - - // Append final integer - if rem_bytes != 0 { - // Only integers can be really split further. - assert_eq!(self.rest.unit.kind, RegKind::Integer); - args.push(cx.type_ix(rem_bytes * 8)); + return cx.type_array(rest_ll_unit, rest_count); } + // Generate a struct type with the prefix and the "rest" arguments. + let prefix_args = + self.prefix.iter().flat_map(|option_reg| option_reg.map(|reg| reg.llvm_type(cx))); + let rest_args = (0..rest_count).map(|_| rest_ll_unit); + let args: Vec<_> = prefix_args.chain(rest_args).collect(); cx.type_struct(&args, false) } } @@ -215,47 +211,33 @@ impl<'ll, 'tcx> ArgAbiExt<'ll, 'tcx> for ArgAbi<'tcx, Ty<'tcx>> { bug!("unsized `ArgAbi` must be handled through `store_fn_arg`"); } PassMode::Cast { cast, pad_i32: _ } => { - // FIXME(eddyb): Figure out when the simpler Store is safe, clang - // uses it for i16 -> {i8, i8}, but not for i24 -> {i8, i8, i8}. - let can_store_through_cast_ptr = false; - if can_store_through_cast_ptr { - bx.store(val, dst.llval, self.layout.align.abi); - } else { - // The actual return type is a struct, but the ABI - // adaptation code has cast it into some scalar type. The - // code that follows is the only reliable way I have - // found to do a transform like i64 -> {i32,i32}. - // Basically we dump the data onto the stack then memcpy it. - // - // Other approaches I tried: - // - Casting rust ret pointer to the foreign type and using Store - // is (a) unsafe if size of foreign type > size of rust type and - // (b) runs afoul of strict aliasing rules, yielding invalid - // assembly under -O (specifically, the store gets removed). - // - Truncating foreign type to correct integral type and then - // bitcasting to the struct type yields invalid cast errors. - - // We instead thus allocate some scratch space... - let scratch_size = cast.size(bx); - let scratch_align = cast.align(bx); - let llscratch = bx.alloca(cast.llvm_type(bx), scratch_align); - bx.lifetime_start(llscratch, scratch_size); - - // ... where we first store the value... - bx.store(val, llscratch, scratch_align); - - // ... and then memcpy it to the intended destination. - bx.memcpy( - dst.llval, - self.layout.align.abi, - llscratch, - scratch_align, - bx.const_usize(self.layout.size.bytes()), - MemFlags::empty(), - ); - - bx.lifetime_end(llscratch, scratch_size); - } + // The ABI mandates that the value is passed as a different struct representation. + // Spill and reload it from the stack to convert from the ABI representation to + // the Rust representation. + let scratch_size = cast.size(bx); + let scratch_align = cast.align(bx); + // Note that the ABI type may be either larger or smaller than the Rust type, + // due to the presence or absence of trailing padding. For example: + // - On some ABIs, the Rust layout { f64, f32, <f32 padding> } may omit padding + // when passed by value, making it smaller. + // - On some ABIs, the Rust layout { u16, u16, u16 } may be padded up to 8 bytes + // when passed by value, making it larger. + let copy_bytes = cmp::min(scratch_size.bytes(), self.layout.size.bytes()); + // Allocate some scratch space... + let llscratch = bx.alloca(cast.llvm_type(bx), scratch_align); + bx.lifetime_start(llscratch, scratch_size); + // ...store the value... + bx.store(val, llscratch, scratch_align); + // ... and then memcpy it to the intended destination. + bx.memcpy( + dst.llval, + self.layout.align.abi, + llscratch, + scratch_align, + bx.const_usize(copy_bytes), + MemFlags::empty(), + ); + bx.lifetime_end(llscratch, scratch_size); } _ => { OperandRef::from_immediate_or_packed_pair(bx, val, self.layout).val.store(bx, dst); diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs index e4ec7974e90..dc52dd156b7 100644 --- a/compiler/rustc_codegen_llvm/src/intrinsic.rs +++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs @@ -2111,7 +2111,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>( return Ok(args[0].immediate()); } - if name == sym::simd_expose_addr { + if name == sym::simd_expose_provenance { let (out_len, out_elem) = require_simd!(ret_ty, SimdReturn); require!( in_len == out_len, |