granite-rust/compiler/rustc_codegen_ssa/src/base.rs
Scott McMurray b5b6def021 Use FieldIdx in various things related to aggregates
Shrank `AggregateKind` by 8 bytes on x64, since the active field of a union is tracked as an `Option<FieldIdx>` instead of `Option<usize>`.
2023-04-01 20:32:50 -07:00

1027 lines
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Rust
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use crate::back::link::are_upstream_rust_objects_already_included;
use crate::back::metadata::create_compressed_metadata_file;
use crate::back::write::{
compute_per_cgu_lto_type, start_async_codegen, submit_codegened_module_to_llvm,
submit_post_lto_module_to_llvm, submit_pre_lto_module_to_llvm, ComputedLtoType, OngoingCodegen,
};
use crate::common::{IntPredicate, RealPredicate, TypeKind};
use crate::errors;
use crate::meth;
use crate::mir;
use crate::mir::operand::OperandValue;
use crate::mir::place::PlaceRef;
use crate::traits::*;
use crate::{CachedModuleCodegen, CompiledModule, CrateInfo, MemFlags, ModuleCodegen, ModuleKind};
use rustc_ast::expand::allocator::AllocatorKind;
use rustc_attr as attr;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_data_structures::profiling::{get_resident_set_size, print_time_passes_entry};
use rustc_data_structures::sync::par_iter;
#[cfg(parallel_compiler)]
use rustc_data_structures::sync::ParallelIterator;
use rustc_hir as hir;
use rustc_hir::def_id::{DefId, LOCAL_CRATE};
use rustc_hir::lang_items::LangItem;
use rustc_metadata::EncodedMetadata;
use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
use rustc_middle::middle::exported_symbols;
use rustc_middle::middle::exported_symbols::SymbolExportKind;
use rustc_middle::middle::lang_items;
use rustc_middle::mir::mono::{CodegenUnit, CodegenUnitNameBuilder, MonoItem};
use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, TyAndLayout};
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
use rustc_session::cgu_reuse_tracker::CguReuse;
use rustc_session::config::{self, CrateType, EntryFnType, OutputType};
use rustc_session::Session;
use rustc_span::symbol::sym;
use rustc_span::Symbol;
use rustc_span::{DebuggerVisualizerFile, DebuggerVisualizerType};
use rustc_target::abi::{Align, FIRST_VARIANT};
use std::collections::BTreeSet;
use std::time::{Duration, Instant};
use itertools::Itertools;
pub fn bin_op_to_icmp_predicate(op: hir::BinOpKind, signed: bool) -> IntPredicate {
match op {
hir::BinOpKind::Eq => IntPredicate::IntEQ,
hir::BinOpKind::Ne => IntPredicate::IntNE,
hir::BinOpKind::Lt => {
if signed {
IntPredicate::IntSLT
} else {
IntPredicate::IntULT
}
}
hir::BinOpKind::Le => {
if signed {
IntPredicate::IntSLE
} else {
IntPredicate::IntULE
}
}
hir::BinOpKind::Gt => {
if signed {
IntPredicate::IntSGT
} else {
IntPredicate::IntUGT
}
}
hir::BinOpKind::Ge => {
if signed {
IntPredicate::IntSGE
} else {
IntPredicate::IntUGE
}
}
op => bug!(
"comparison_op_to_icmp_predicate: expected comparison operator, \
found {:?}",
op
),
}
}
pub fn bin_op_to_fcmp_predicate(op: hir::BinOpKind) -> RealPredicate {
match op {
hir::BinOpKind::Eq => RealPredicate::RealOEQ,
hir::BinOpKind::Ne => RealPredicate::RealUNE,
hir::BinOpKind::Lt => RealPredicate::RealOLT,
hir::BinOpKind::Le => RealPredicate::RealOLE,
hir::BinOpKind::Gt => RealPredicate::RealOGT,
hir::BinOpKind::Ge => RealPredicate::RealOGE,
op => {
bug!(
"comparison_op_to_fcmp_predicate: expected comparison operator, \
found {:?}",
op
);
}
}
}
pub fn compare_simd_types<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
lhs: Bx::Value,
rhs: Bx::Value,
t: Ty<'tcx>,
ret_ty: Bx::Type,
op: hir::BinOpKind,
) -> Bx::Value {
let signed = match t.kind() {
ty::Float(_) => {
let cmp = bin_op_to_fcmp_predicate(op);
let cmp = bx.fcmp(cmp, lhs, rhs);
return bx.sext(cmp, ret_ty);
}
ty::Uint(_) => false,
ty::Int(_) => true,
_ => bug!("compare_simd_types: invalid SIMD type"),
};
let cmp = bin_op_to_icmp_predicate(op, signed);
let cmp = bx.icmp(cmp, lhs, rhs);
// LLVM outputs an `< size x i1 >`, so we need to perform a sign extension
// to get the correctly sized type. This will compile to a single instruction
// once the IR is converted to assembly if the SIMD instruction is supported
// by the target architecture.
bx.sext(cmp, ret_ty)
}
/// Retrieves the information we are losing (making dynamic) in an unsizing
/// adjustment.
///
/// The `old_info` argument is a bit odd. It is intended for use in an upcast,
/// where the new vtable for an object will be derived from the old one.
pub fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
source: Ty<'tcx>,
target: Ty<'tcx>,
old_info: Option<Bx::Value>,
) -> Bx::Value {
let cx = bx.cx();
let (source, target) =
cx.tcx().struct_lockstep_tails_erasing_lifetimes(source, target, bx.param_env());
match (source.kind(), target.kind()) {
(&ty::Array(_, len), &ty::Slice(_)) => {
cx.const_usize(len.eval_target_usize(cx.tcx(), ty::ParamEnv::reveal_all()))
}
(
&ty::Dynamic(ref data_a, _, src_dyn_kind),
&ty::Dynamic(ref data_b, _, target_dyn_kind),
) if src_dyn_kind == target_dyn_kind => {
let old_info =
old_info.expect("unsized_info: missing old info for trait upcasting coercion");
if data_a.principal_def_id() == data_b.principal_def_id() {
// A NOP cast that doesn't actually change anything, should be allowed even with invalid vtables.
return old_info;
}
// trait upcasting coercion
let vptr_entry_idx =
cx.tcx().vtable_trait_upcasting_coercion_new_vptr_slot((source, target));
if let Some(entry_idx) = vptr_entry_idx {
let ptr_ty = cx.type_i8p();
let ptr_align = cx.tcx().data_layout.pointer_align.abi;
let vtable_ptr_ty = vtable_ptr_ty(cx, target, target_dyn_kind);
let llvtable = bx.pointercast(old_info, bx.type_ptr_to(ptr_ty));
let gep = bx.inbounds_gep(
ptr_ty,
llvtable,
&[bx.const_usize(u64::try_from(entry_idx).unwrap())],
);
let new_vptr = bx.load(ptr_ty, gep, ptr_align);
bx.nonnull_metadata(new_vptr);
// VTable loads are invariant.
bx.set_invariant_load(new_vptr);
bx.pointercast(new_vptr, vtable_ptr_ty)
} else {
old_info
}
}
(_, &ty::Dynamic(ref data, _, target_dyn_kind)) => {
let vtable_ptr_ty = vtable_ptr_ty(cx, target, target_dyn_kind);
cx.const_ptrcast(meth::get_vtable(cx, source, data.principal()), vtable_ptr_ty)
}
_ => bug!("unsized_info: invalid unsizing {:?} -> {:?}", source, target),
}
}
// Returns the vtable pointer type of a `dyn` or `dyn*` type
fn vtable_ptr_ty<'tcx, Cx: CodegenMethods<'tcx>>(
cx: &Cx,
target: Ty<'tcx>,
kind: ty::DynKind,
) -> <Cx as BackendTypes>::Type {
cx.scalar_pair_element_backend_type(
cx.layout_of(match kind {
// vtable is the second field of `*mut dyn Trait`
ty::Dyn => cx.tcx().mk_mut_ptr(target),
// vtable is the second field of `dyn* Trait`
ty::DynStar => target,
}),
1,
true,
)
}
/// Coerces `src` to `dst_ty`. `src_ty` must be a pointer.
pub fn unsize_ptr<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
src: Bx::Value,
src_ty: Ty<'tcx>,
dst_ty: Ty<'tcx>,
old_info: Option<Bx::Value>,
) -> (Bx::Value, Bx::Value) {
debug!("unsize_ptr: {:?} => {:?}", src_ty, dst_ty);
match (src_ty.kind(), dst_ty.kind()) {
(&ty::Ref(_, a, _), &ty::Ref(_, b, _) | &ty::RawPtr(ty::TypeAndMut { ty: b, .. }))
| (&ty::RawPtr(ty::TypeAndMut { ty: a, .. }), &ty::RawPtr(ty::TypeAndMut { ty: b, .. })) => {
assert_eq!(bx.cx().type_is_sized(a), old_info.is_none());
let ptr_ty = bx.cx().type_ptr_to(bx.cx().backend_type(bx.cx().layout_of(b)));
(bx.pointercast(src, ptr_ty), unsized_info(bx, a, b, old_info))
}
(&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
assert_eq!(def_a, def_b);
let src_layout = bx.cx().layout_of(src_ty);
let dst_layout = bx.cx().layout_of(dst_ty);
if src_ty == dst_ty {
return (src, old_info.unwrap());
}
let mut result = None;
for i in 0..src_layout.fields.count() {
let src_f = src_layout.field(bx.cx(), i);
if src_f.is_zst() {
continue;
}
assert_eq!(src_layout.fields.offset(i).bytes(), 0);
assert_eq!(dst_layout.fields.offset(i).bytes(), 0);
assert_eq!(src_layout.size, src_f.size);
let dst_f = dst_layout.field(bx.cx(), i);
assert_ne!(src_f.ty, dst_f.ty);
assert_eq!(result, None);
result = Some(unsize_ptr(bx, src, src_f.ty, dst_f.ty, old_info));
}
let (lldata, llextra) = result.unwrap();
let lldata_ty = bx.cx().scalar_pair_element_backend_type(dst_layout, 0, true);
let llextra_ty = bx.cx().scalar_pair_element_backend_type(dst_layout, 1, true);
// HACK(eddyb) have to bitcast pointers until LLVM removes pointee types.
(bx.bitcast(lldata, lldata_ty), bx.bitcast(llextra, llextra_ty))
}
_ => bug!("unsize_ptr: called on bad types"),
}
}
/// Coerces `src` to `dst_ty` which is guaranteed to be a `dyn*` type.
pub fn cast_to_dyn_star<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
src: Bx::Value,
src_ty_and_layout: TyAndLayout<'tcx>,
dst_ty: Ty<'tcx>,
old_info: Option<Bx::Value>,
) -> (Bx::Value, Bx::Value) {
debug!("cast_to_dyn_star: {:?} => {:?}", src_ty_and_layout.ty, dst_ty);
assert!(
matches!(dst_ty.kind(), ty::Dynamic(_, _, ty::DynStar)),
"destination type must be a dyn*"
);
// FIXME(dyn-star): We can remove this when all supported LLVMs use opaque ptrs only.
let unit_ptr = bx.cx().type_ptr_to(bx.cx().type_struct(&[], false));
let src = match bx.cx().type_kind(bx.cx().backend_type(src_ty_and_layout)) {
TypeKind::Pointer => bx.pointercast(src, unit_ptr),
TypeKind::Integer => bx.inttoptr(src, unit_ptr),
// FIXME(dyn-star): We probably have to do a bitcast first, then inttoptr.
kind => bug!("unexpected TypeKind for left-hand side of `dyn*` cast: {kind:?}"),
};
(src, unsized_info(bx, src_ty_and_layout.ty, dst_ty, old_info))
}
/// Coerces `src`, which is a reference to a value of type `src_ty`,
/// to a value of type `dst_ty`, and stores the result in `dst`.
pub fn coerce_unsized_into<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
src: PlaceRef<'tcx, Bx::Value>,
dst: PlaceRef<'tcx, Bx::Value>,
) {
let src_ty = src.layout.ty;
let dst_ty = dst.layout.ty;
match (src_ty.kind(), dst_ty.kind()) {
(&ty::Ref(..), &ty::Ref(..) | &ty::RawPtr(..)) | (&ty::RawPtr(..), &ty::RawPtr(..)) => {
let (base, info) = match bx.load_operand(src).val {
OperandValue::Pair(base, info) => unsize_ptr(bx, base, src_ty, dst_ty, Some(info)),
OperandValue::Immediate(base) => unsize_ptr(bx, base, src_ty, dst_ty, None),
OperandValue::Ref(..) => bug!(),
};
OperandValue::Pair(base, info).store(bx, dst);
}
(&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
assert_eq!(def_a, def_b);
for i in def_a.variant(FIRST_VARIANT).fields.indices() {
let src_f = src.project_field(bx, i.as_usize());
let dst_f = dst.project_field(bx, i.as_usize());
if dst_f.layout.is_zst() {
continue;
}
if src_f.layout.ty == dst_f.layout.ty {
memcpy_ty(
bx,
dst_f.llval,
dst_f.align,
src_f.llval,
src_f.align,
src_f.layout,
MemFlags::empty(),
);
} else {
coerce_unsized_into(bx, src_f, dst_f);
}
}
}
_ => bug!("coerce_unsized_into: invalid coercion {:?} -> {:?}", src_ty, dst_ty,),
}
}
pub fn cast_shift_expr_rhs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
lhs: Bx::Value,
rhs: Bx::Value,
) -> Bx::Value {
// Shifts may have any size int on the rhs
let mut rhs_llty = bx.cx().val_ty(rhs);
let mut lhs_llty = bx.cx().val_ty(lhs);
if bx.cx().type_kind(rhs_llty) == TypeKind::Vector {
rhs_llty = bx.cx().element_type(rhs_llty)
}
if bx.cx().type_kind(lhs_llty) == TypeKind::Vector {
lhs_llty = bx.cx().element_type(lhs_llty)
}
let rhs_sz = bx.cx().int_width(rhs_llty);
let lhs_sz = bx.cx().int_width(lhs_llty);
if lhs_sz < rhs_sz {
bx.trunc(rhs, lhs_llty)
} else if lhs_sz > rhs_sz {
// FIXME (#1877: If in the future shifting by negative
// values is no longer undefined then this is wrong.
bx.zext(rhs, lhs_llty)
} else {
rhs
}
}
/// Returns `true` if this session's target will use SEH-based unwinding.
///
/// This is only true for MSVC targets, and even then the 64-bit MSVC target
/// currently uses SEH-ish unwinding with DWARF info tables to the side (same as
/// 64-bit MinGW) instead of "full SEH".
pub fn wants_msvc_seh(sess: &Session) -> bool {
sess.target.is_like_msvc
}
pub fn memcpy_ty<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
dst: Bx::Value,
dst_align: Align,
src: Bx::Value,
src_align: Align,
layout: TyAndLayout<'tcx>,
flags: MemFlags,
) {
let size = layout.size.bytes();
if size == 0 {
return;
}
bx.memcpy(dst, dst_align, src, src_align, bx.cx().const_usize(size), flags);
}
pub fn codegen_instance<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
cx: &'a Bx::CodegenCx,
instance: Instance<'tcx>,
) {
// this is an info! to allow collecting monomorphization statistics
// and to allow finding the last function before LLVM aborts from
// release builds.
info!("codegen_instance({})", instance);
mir::codegen_mir::<Bx>(cx, instance);
}
/// Creates the `main` function which will initialize the rust runtime and call
/// users main function.
pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
cx: &'a Bx::CodegenCx,
) -> Option<Bx::Function> {
let (main_def_id, entry_type) = cx.tcx().entry_fn(())?;
let main_is_local = main_def_id.is_local();
let instance = Instance::mono(cx.tcx(), main_def_id);
if main_is_local {
// We want to create the wrapper in the same codegen unit as Rust's main
// function.
if !cx.codegen_unit().contains_item(&MonoItem::Fn(instance)) {
return None;
}
} else if !cx.codegen_unit().is_primary() {
// We want to create the wrapper only when the codegen unit is the primary one
return None;
}
let main_llfn = cx.get_fn_addr(instance);
let entry_fn = create_entry_fn::<Bx>(cx, main_llfn, main_def_id, entry_type);
return Some(entry_fn);
fn create_entry_fn<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
cx: &'a Bx::CodegenCx,
rust_main: Bx::Value,
rust_main_def_id: DefId,
entry_type: EntryFnType,
) -> Bx::Function {
// The entry function is either `int main(void)` or `int main(int argc, char **argv)`,
// depending on whether the target needs `argc` and `argv` to be passed in.
let llfty = if cx.sess().target.main_needs_argc_argv {
cx.type_func(&[cx.type_int(), cx.type_ptr_to(cx.type_i8p())], cx.type_int())
} else {
cx.type_func(&[], cx.type_int())
};
let main_ret_ty = cx.tcx().fn_sig(rust_main_def_id).no_bound_vars().unwrap().output();
// Given that `main()` has no arguments,
// then its return type cannot have
// late-bound regions, since late-bound
// regions must appear in the argument
// listing.
let main_ret_ty = cx.tcx().normalize_erasing_regions(
ty::ParamEnv::reveal_all(),
main_ret_ty.no_bound_vars().unwrap(),
);
let Some(llfn) = cx.declare_c_main(llfty) else {
// FIXME: We should be smart and show a better diagnostic here.
let span = cx.tcx().def_span(rust_main_def_id);
cx.sess().emit_err(errors::MultipleMainFunctions { span });
cx.sess().abort_if_errors();
bug!();
};
// `main` should respect same config for frame pointer elimination as rest of code
cx.set_frame_pointer_type(llfn);
cx.apply_target_cpu_attr(llfn);
let llbb = Bx::append_block(&cx, llfn, "top");
let mut bx = Bx::build(&cx, llbb);
bx.insert_reference_to_gdb_debug_scripts_section_global();
let isize_ty = cx.type_isize();
let i8pp_ty = cx.type_ptr_to(cx.type_i8p());
let (arg_argc, arg_argv) = get_argc_argv(cx, &mut bx);
let (start_fn, start_ty, args) = if let EntryFnType::Main { sigpipe } = entry_type {
let start_def_id = cx.tcx().require_lang_item(LangItem::Start, None);
let start_fn = cx.get_fn_addr(
ty::Instance::resolve(
cx.tcx(),
ty::ParamEnv::reveal_all(),
start_def_id,
cx.tcx().mk_substs(&[main_ret_ty.into()]),
)
.unwrap()
.unwrap(),
);
let i8_ty = cx.type_i8();
let arg_sigpipe = bx.const_u8(sigpipe);
let start_ty =
cx.type_func(&[cx.val_ty(rust_main), isize_ty, i8pp_ty, i8_ty], isize_ty);
(start_fn, start_ty, vec![rust_main, arg_argc, arg_argv, arg_sigpipe])
} else {
debug!("using user-defined start fn");
let start_ty = cx.type_func(&[isize_ty, i8pp_ty], isize_ty);
(rust_main, start_ty, vec![arg_argc, arg_argv])
};
let result = bx.call(start_ty, None, start_fn, &args, None);
let cast = bx.intcast(result, cx.type_int(), true);
bx.ret(cast);
llfn
}
}
/// Obtain the `argc` and `argv` values to pass to the rust start function.
fn get_argc_argv<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
cx: &'a Bx::CodegenCx,
bx: &mut Bx,
) -> (Bx::Value, Bx::Value) {
if cx.sess().target.main_needs_argc_argv {
// Params from native `main()` used as args for rust start function
let param_argc = bx.get_param(0);
let param_argv = bx.get_param(1);
let arg_argc = bx.intcast(param_argc, cx.type_isize(), true);
let arg_argv = param_argv;
(arg_argc, arg_argv)
} else {
// The Rust start function doesn't need `argc` and `argv`, so just pass zeros.
let arg_argc = bx.const_int(cx.type_int(), 0);
let arg_argv = bx.const_null(cx.type_ptr_to(cx.type_i8p()));
(arg_argc, arg_argv)
}
}
/// This function returns all of the debugger visualizers specified for the
/// current crate as well as all upstream crates transitively that match the
/// `visualizer_type` specified.
pub fn collect_debugger_visualizers_transitive(
tcx: TyCtxt<'_>,
visualizer_type: DebuggerVisualizerType,
) -> BTreeSet<DebuggerVisualizerFile> {
tcx.debugger_visualizers(LOCAL_CRATE)
.iter()
.chain(
tcx.crates(())
.iter()
.filter(|&cnum| {
let used_crate_source = tcx.used_crate_source(*cnum);
used_crate_source.rlib.is_some() || used_crate_source.rmeta.is_some()
})
.flat_map(|&cnum| tcx.debugger_visualizers(cnum)),
)
.filter(|visualizer| visualizer.visualizer_type == visualizer_type)
.cloned()
.collect::<BTreeSet<_>>()
}
/// Decide allocator kind to codegen. If `Some(_)` this will be the same as
/// `tcx.allocator_kind`, but it may be `None` in more cases (e.g. if using
/// allocator definitions from a dylib dependency).
pub fn allocator_kind_for_codegen(tcx: TyCtxt<'_>) -> Option<AllocatorKind> {
// If the crate doesn't have an `allocator_kind` set then there's definitely
// no shim to generate. Otherwise we also check our dependency graph for all
// our output crate types. If anything there looks like its a `Dynamic`
// linkage, then it's already got an allocator shim and we'll be using that
// one instead. If nothing exists then it's our job to generate the
// allocator!
let any_dynamic_crate = tcx.dependency_formats(()).iter().any(|(_, list)| {
use rustc_middle::middle::dependency_format::Linkage;
list.iter().any(|&linkage| linkage == Linkage::Dynamic)
});
if any_dynamic_crate { None } else { tcx.allocator_kind(()) }
}
pub fn codegen_crate<B: ExtraBackendMethods>(
backend: B,
tcx: TyCtxt<'_>,
target_cpu: String,
metadata: EncodedMetadata,
need_metadata_module: bool,
) -> OngoingCodegen<B> {
// Skip crate items and just output metadata in -Z no-codegen mode.
if tcx.sess.opts.unstable_opts.no_codegen || !tcx.sess.opts.output_types.should_codegen() {
let ongoing_codegen = start_async_codegen(backend, tcx, target_cpu, metadata, None, 1);
ongoing_codegen.codegen_finished(tcx);
ongoing_codegen.check_for_errors(tcx.sess);
return ongoing_codegen;
}
let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
// Run the monomorphization collector and partition the collected items into
// codegen units.
let codegen_units = tcx.collect_and_partition_mono_items(()).1;
// Force all codegen_unit queries so they are already either red or green
// when compile_codegen_unit accesses them. We are not able to re-execute
// the codegen_unit query from just the DepNode, so an unknown color would
// lead to having to re-execute compile_codegen_unit, possibly
// unnecessarily.
if tcx.dep_graph.is_fully_enabled() {
for cgu in codegen_units {
tcx.ensure().codegen_unit(cgu.name());
}
}
let metadata_module = need_metadata_module.then(|| {
// Emit compressed metadata object.
let metadata_cgu_name =
cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("metadata")).to_string();
tcx.sess.time("write_compressed_metadata", || {
let file_name =
tcx.output_filenames(()).temp_path(OutputType::Metadata, Some(&metadata_cgu_name));
let data = create_compressed_metadata_file(
tcx.sess,
&metadata,
&exported_symbols::metadata_symbol_name(tcx),
);
if let Err(error) = std::fs::write(&file_name, data) {
tcx.sess.emit_fatal(errors::MetadataObjectFileWrite { error });
}
CompiledModule {
name: metadata_cgu_name,
kind: ModuleKind::Metadata,
object: Some(file_name),
dwarf_object: None,
bytecode: None,
}
})
});
let ongoing_codegen = start_async_codegen(
backend.clone(),
tcx,
target_cpu,
metadata,
metadata_module,
codegen_units.len(),
);
// Codegen an allocator shim, if necessary.
if let Some(kind) = allocator_kind_for_codegen(tcx) {
let llmod_id =
cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("allocator")).to_string();
let module_llvm = tcx.sess.time("write_allocator_module", || {
backend.codegen_allocator(
tcx,
&llmod_id,
kind,
// If allocator_kind is Some then alloc_error_handler_kind must
// also be Some.
tcx.alloc_error_handler_kind(()).unwrap(),
)
});
ongoing_codegen.submit_pre_codegened_module_to_llvm(
tcx,
ModuleCodegen { name: llmod_id, module_llvm, kind: ModuleKind::Allocator },
);
}
// For better throughput during parallel processing by LLVM, we used to sort
// CGUs largest to smallest. This would lead to better thread utilization
// by, for example, preventing a large CGU from being processed last and
// having only one LLVM thread working while the rest remained idle.
//
// However, this strategy would lead to high memory usage, as it meant the
// LLVM-IR for all of the largest CGUs would be resident in memory at once.
//
// Instead, we can compromise by ordering CGUs such that the largest and
// smallest are first, second largest and smallest are next, etc. If there
// are large size variations, this can reduce memory usage significantly.
let codegen_units: Vec<_> = {
let mut sorted_cgus = codegen_units.iter().collect::<Vec<_>>();
sorted_cgus.sort_by_cached_key(|cgu| cgu.size_estimate());
let (first_half, second_half) = sorted_cgus.split_at(sorted_cgus.len() / 2);
second_half.iter().rev().interleave(first_half).copied().collect()
};
// Calculate the CGU reuse
let cgu_reuse = tcx.sess.time("find_cgu_reuse", || {
codegen_units.iter().map(|cgu| determine_cgu_reuse(tcx, &cgu)).collect::<Vec<_>>()
});
let mut total_codegen_time = Duration::new(0, 0);
let start_rss = tcx.sess.opts.unstable_opts.time_passes.then(|| get_resident_set_size());
// The non-parallel compiler can only translate codegen units to LLVM IR
// on a single thread, leading to a staircase effect where the N LLVM
// threads have to wait on the single codegen threads to generate work
// for them. The parallel compiler does not have this restriction, so
// we can pre-load the LLVM queue in parallel before handing off
// coordination to the OnGoingCodegen scheduler.
//
// This likely is a temporary measure. Once we don't have to support the
// non-parallel compiler anymore, we can compile CGUs end-to-end in
// parallel and get rid of the complicated scheduling logic.
let mut pre_compiled_cgus = if cfg!(parallel_compiler) {
tcx.sess.time("compile_first_CGU_batch", || {
// Try to find one CGU to compile per thread.
let cgus: Vec<_> = cgu_reuse
.iter()
.enumerate()
.filter(|&(_, reuse)| reuse == &CguReuse::No)
.take(tcx.sess.threads())
.collect();
// Compile the found CGUs in parallel.
let start_time = Instant::now();
let pre_compiled_cgus = par_iter(cgus)
.map(|(i, _)| {
let module = backend.compile_codegen_unit(tcx, codegen_units[i].name());
(i, module)
})
.collect();
total_codegen_time += start_time.elapsed();
pre_compiled_cgus
})
} else {
FxHashMap::default()
};
for (i, cgu) in codegen_units.iter().enumerate() {
ongoing_codegen.wait_for_signal_to_codegen_item();
ongoing_codegen.check_for_errors(tcx.sess);
let cgu_reuse = cgu_reuse[i];
tcx.sess.cgu_reuse_tracker.set_actual_reuse(cgu.name().as_str(), cgu_reuse);
match cgu_reuse {
CguReuse::No => {
let (module, cost) = if let Some(cgu) = pre_compiled_cgus.remove(&i) {
cgu
} else {
let start_time = Instant::now();
let module = backend.compile_codegen_unit(tcx, cgu.name());
total_codegen_time += start_time.elapsed();
module
};
// This will unwind if there are errors, which triggers our `AbortCodegenOnDrop`
// guard. Unfortunately, just skipping the `submit_codegened_module_to_llvm` makes
// compilation hang on post-monomorphization errors.
tcx.sess.abort_if_errors();
submit_codegened_module_to_llvm(
&backend,
&ongoing_codegen.coordinator.sender,
module,
cost,
);
false
}
CguReuse::PreLto => {
submit_pre_lto_module_to_llvm(
&backend,
tcx,
&ongoing_codegen.coordinator.sender,
CachedModuleCodegen {
name: cgu.name().to_string(),
source: cgu.previous_work_product(tcx),
},
);
true
}
CguReuse::PostLto => {
submit_post_lto_module_to_llvm(
&backend,
&ongoing_codegen.coordinator.sender,
CachedModuleCodegen {
name: cgu.name().to_string(),
source: cgu.previous_work_product(tcx),
},
);
true
}
};
}
ongoing_codegen.codegen_finished(tcx);
// Since the main thread is sometimes blocked during codegen, we keep track
// -Ztime-passes output manually.
if tcx.sess.opts.unstable_opts.time_passes {
let end_rss = get_resident_set_size();
print_time_passes_entry(
"codegen_to_LLVM_IR",
total_codegen_time,
start_rss.unwrap(),
end_rss,
tcx.sess.opts.unstable_opts.time_passes_format,
);
}
ongoing_codegen.check_for_errors(tcx.sess);
ongoing_codegen
}
impl CrateInfo {
pub fn new(tcx: TyCtxt<'_>, target_cpu: String) -> CrateInfo {
let exported_symbols = tcx
.sess
.crate_types()
.iter()
.map(|&c| (c, crate::back::linker::exported_symbols(tcx, c)))
.collect();
let linked_symbols = tcx
.sess
.crate_types()
.iter()
.map(|&c| (c, crate::back::linker::linked_symbols(tcx, c)))
.collect();
let local_crate_name = tcx.crate_name(LOCAL_CRATE);
let crate_attrs = tcx.hir().attrs(rustc_hir::CRATE_HIR_ID);
let subsystem = attr::first_attr_value_str_by_name(crate_attrs, sym::windows_subsystem);
let windows_subsystem = subsystem.map(|subsystem| {
if subsystem != sym::windows && subsystem != sym::console {
tcx.sess.emit_fatal(errors::InvalidWindowsSubsystem { subsystem });
}
subsystem.to_string()
});
// This list is used when generating the command line to pass through to
// system linker. The linker expects undefined symbols on the left of the
// command line to be defined in libraries on the right, not the other way
// around. For more info, see some comments in the add_used_library function
// below.
//
// In order to get this left-to-right dependency ordering, we use the reverse
// postorder of all crates putting the leaves at the right-most positions.
let mut compiler_builtins = None;
let mut used_crates: Vec<_> = tcx
.postorder_cnums(())
.iter()
.rev()
.copied()
.filter(|&cnum| {
let link = !tcx.dep_kind(cnum).macros_only();
if link && tcx.is_compiler_builtins(cnum) {
compiler_builtins = Some(cnum);
return false;
}
link
})
.collect();
// `compiler_builtins` are always placed last to ensure that they're linked correctly.
used_crates.extend(compiler_builtins);
let mut info = CrateInfo {
target_cpu,
exported_symbols,
linked_symbols,
local_crate_name,
compiler_builtins,
profiler_runtime: None,
is_no_builtins: Default::default(),
native_libraries: Default::default(),
used_libraries: tcx.native_libraries(LOCAL_CRATE).iter().map(Into::into).collect(),
crate_name: Default::default(),
used_crates,
used_crate_source: Default::default(),
dependency_formats: tcx.dependency_formats(()).clone(),
windows_subsystem,
natvis_debugger_visualizers: Default::default(),
feature_packed_bundled_libs: tcx.features().packed_bundled_libs,
};
let crates = tcx.crates(());
let n_crates = crates.len();
info.native_libraries.reserve(n_crates);
info.crate_name.reserve(n_crates);
info.used_crate_source.reserve(n_crates);
for &cnum in crates.iter() {
info.native_libraries
.insert(cnum, tcx.native_libraries(cnum).iter().map(Into::into).collect());
info.crate_name.insert(cnum, tcx.crate_name(cnum));
let used_crate_source = tcx.used_crate_source(cnum);
info.used_crate_source.insert(cnum, used_crate_source.clone());
if tcx.is_profiler_runtime(cnum) {
info.profiler_runtime = Some(cnum);
}
if tcx.is_no_builtins(cnum) {
info.is_no_builtins.insert(cnum);
}
}
// Handle circular dependencies in the standard library.
// See comment before `add_linked_symbol_object` function for the details.
// If global LTO is enabled then almost everything (*) is glued into a single object file,
// so this logic is not necessary and can cause issues on some targets (due to weak lang
// item symbols being "privatized" to that object file), so we disable it.
// (*) Native libs, and `#[compiler_builtins]` and `#[no_builtins]` crates are not glued,
// and we assume that they cannot define weak lang items. This is not currently enforced
// by the compiler, but that's ok because all this stuff is unstable anyway.
let target = &tcx.sess.target;
if !are_upstream_rust_objects_already_included(tcx.sess) {
let missing_weak_lang_items: FxHashSet<Symbol> = info
.used_crates
.iter()
.flat_map(|&cnum| tcx.missing_lang_items(cnum))
.filter(|l| l.is_weak())
.filter_map(|&l| {
let name = l.link_name()?;
lang_items::required(tcx, l).then_some(name)
})
.collect();
let prefix = if target.is_like_windows && target.arch == "x86" { "_" } else { "" };
info.linked_symbols
.iter_mut()
.filter(|(crate_type, _)| {
!matches!(crate_type, CrateType::Rlib | CrateType::Staticlib)
})
.for_each(|(_, linked_symbols)| {
linked_symbols.extend(
missing_weak_lang_items
.iter()
.map(|item| (format!("{prefix}{item}"), SymbolExportKind::Text)),
)
});
}
let embed_visualizers = tcx.sess.crate_types().iter().any(|&crate_type| match crate_type {
CrateType::Executable | CrateType::Dylib | CrateType::Cdylib => {
// These are crate types for which we invoke the linker and can embed
// NatVis visualizers.
true
}
CrateType::ProcMacro => {
// We could embed NatVis for proc macro crates too (to improve the debugging
// experience for them) but it does not seem like a good default, since
// this is a rare use case and we don't want to slow down the common case.
false
}
CrateType::Staticlib | CrateType::Rlib => {
// We don't invoke the linker for these, so we don't need to collect the NatVis for them.
false
}
});
if target.is_like_msvc && embed_visualizers {
info.natvis_debugger_visualizers =
collect_debugger_visualizers_transitive(tcx, DebuggerVisualizerType::Natvis);
}
info
}
}
pub fn provide(providers: &mut Providers) {
providers.backend_optimization_level = |tcx, cratenum| {
let for_speed = match tcx.sess.opts.optimize {
// If globally no optimisation is done, #[optimize] has no effect.
//
// This is done because if we ended up "upgrading" to `-O2` here, wed populate the
// pass manager and it is likely that some module-wide passes (such as inliner or
// cross-function constant propagation) would ignore the `optnone` annotation we put
// on the functions, thus necessarily involving these functions into optimisations.
config::OptLevel::No => return config::OptLevel::No,
// If globally optimise-speed is already specified, just use that level.
config::OptLevel::Less => return config::OptLevel::Less,
config::OptLevel::Default => return config::OptLevel::Default,
config::OptLevel::Aggressive => return config::OptLevel::Aggressive,
// If globally optimize-for-size has been requested, use -O2 instead (if optimize(size)
// are present).
config::OptLevel::Size => config::OptLevel::Default,
config::OptLevel::SizeMin => config::OptLevel::Default,
};
let (defids, _) = tcx.collect_and_partition_mono_items(cratenum);
let any_for_speed = defids.items().any(|id| {
let CodegenFnAttrs { optimize, .. } = tcx.codegen_fn_attrs(*id);
match optimize {
attr::OptimizeAttr::None | attr::OptimizeAttr::Size => false,
attr::OptimizeAttr::Speed => true,
}
});
if any_for_speed {
return for_speed;
}
tcx.sess.opts.optimize
};
}
fn determine_cgu_reuse<'tcx>(tcx: TyCtxt<'tcx>, cgu: &CodegenUnit<'tcx>) -> CguReuse {
if !tcx.dep_graph.is_fully_enabled() {
return CguReuse::No;
}
let work_product_id = &cgu.work_product_id();
if tcx.dep_graph.previous_work_product(work_product_id).is_none() {
// We don't have anything cached for this CGU. This can happen
// if the CGU did not exist in the previous session.
return CguReuse::No;
}
// Try to mark the CGU as green. If it we can do so, it means that nothing
// affecting the LLVM module has changed and we can re-use a cached version.
// If we compile with any kind of LTO, this means we can re-use the bitcode
// of the Pre-LTO stage (possibly also the Post-LTO version but we'll only
// know that later). If we are not doing LTO, there is only one optimized
// version of each module, so we re-use that.
let dep_node = cgu.codegen_dep_node(tcx);
assert!(
!tcx.dep_graph.dep_node_exists(&dep_node),
"CompileCodegenUnit dep-node for CGU `{}` already exists before marking.",
cgu.name()
);
if tcx.try_mark_green(&dep_node) {
// We can re-use either the pre- or the post-thinlto state. If no LTO is
// being performed then we can use post-LTO artifacts, otherwise we must
// reuse pre-LTO artifacts
match compute_per_cgu_lto_type(
&tcx.sess.lto(),
&tcx.sess.opts,
&tcx.sess.crate_types(),
ModuleKind::Regular,
) {
ComputedLtoType::No => CguReuse::PostLto,
_ => CguReuse::PreLto,
}
} else {
CguReuse::No
}
}