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mark 2020-08-27 22:58:48 -05:00 • committed by Vadim Petrochenkov
parent db534b3ac2
commit 9e5f7d5631
1686 changed files with 941 additions and 1051 deletions
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compiler/rustc_codegen_ssa/src/base.rs Normal file
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//! Codegen the completed AST to the LLVM IR.
//!
//! Some functions here, such as `codegen_block` and `codegen_expr`, return a value --
//! the result of the codegen to LLVM -- while others, such as `codegen_fn`
//! and `mono_item`, are called only for the side effect of adding a
//! particular definition to the LLVM IR output we're producing.
//!
//! Hopefully useful general knowledge about codegen:
//!
//! * There's no way to find out the `Ty` type of a `Value`. Doing so
//! would be "trying to get the eggs out of an omelette" (credit:
//! pcwalton). You can, instead, find out its `llvm::Type` by calling `val_ty`,
//! but one `llvm::Type` corresponds to many `Ty`s; for instance, `tup(int, int,
//! int)` and `rec(x=int, y=int, z=int)` will have the same `llvm::Type`.
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::meth;
use crate::mir;
use crate::mir::operand::OperandValue;
use crate::mir::place::PlaceRef;
use crate::traits::*;
use crate::{CachedModuleCodegen, CrateInfo, MemFlags, ModuleCodegen, ModuleKind};
use rustc_attr as attr;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::profiling::print_time_passes_entry;
use rustc_data_structures::sync::{par_iter, Lock, ParallelIterator};
use rustc_hir as hir;
use rustc_hir::def_id::{LocalDefId, LOCAL_CRATE};
use rustc_hir::lang_items::LangItem;
use rustc_index::vec::Idx;
use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
use rustc_middle::middle::cstore::EncodedMetadata;
use rustc_middle::middle::cstore::{self, LinkagePreference};
use rustc_middle::middle::lang_items;
use rustc_middle::mir::mono::{CodegenUnit, CodegenUnitNameBuilder, MonoItem};
use rustc_middle::ty::layout::{self, HasTyCtxt, TyAndLayout};
use rustc_middle::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
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, EntryFnType};
use rustc_session::utils::NativeLibKind;
use rustc_session::Session;
use rustc_span::Span;
use rustc_symbol_mangling::test as symbol_names_test;
use rustc_target::abi::{Abi, Align, LayoutOf, Scalar, VariantIdx};
use std::cmp;
use std::ops::{Deref, DerefMut};
use std::time::{Duration, Instant};
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<'tcx, Cx: CodegenMethods<'tcx>>(
cx: &Cx,
source: Ty<'tcx>,
target: Ty<'tcx>,
old_info: Option<Cx::Value>,
) -> Cx::Value {
let (source, target) =
cx.tcx().struct_lockstep_tails_erasing_lifetimes(source, target, cx.param_env());
match (&source.kind, &target.kind) {
(&ty::Array(_, len), &ty::Slice(_)) => {
cx.const_usize(len.eval_usize(cx.tcx(), ty::ParamEnv::reveal_all()))
}
(&ty::Dynamic(..), &ty::Dynamic(..)) => {
// For now, upcasts are limited to changes in marker
// traits, and hence never actually require an actual
// change to the vtable.
old_info.expect("unsized_info: missing old info for trait upcast")
}
(_, &ty::Dynamic(ref data, ..)) => {
let vtable_ptr = cx.layout_of(cx.tcx().mk_mut_ptr(target)).field(cx, FAT_PTR_EXTRA);
cx.const_ptrcast(
meth::get_vtable(cx, source, data.principal()),
cx.backend_type(vtable_ptr),
)
}
_ => bug!("unsized_info: invalid unsizing {:?} -> {:?}", source, target),
}
}
/// Coerces `src` to `dst_ty`. `src_ty` must be a thin pointer.
pub fn unsize_thin_ptr<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
src: Bx::Value,
src_ty: Ty<'tcx>,
dst_ty: Ty<'tcx>,
) -> (Bx::Value, Bx::Value) {
debug!("unsize_thin_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!(bx.cx().type_is_sized(a));
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.cx(), a, b, None))
}
(&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);
let mut result = None;
for i in 0..src_layout.fields.count() {
let src_f = src_layout.field(bx.cx(), i);
assert_eq!(src_layout.fields.offset(i).bytes(), 0);
assert_eq!(dst_layout.fields.offset(i).bytes(), 0);
if src_f.is_zst() {
continue;
}
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_thin_ptr(bx, src, src_f.ty, dst_f.ty));
}
let (lldata, llextra) = result.unwrap();
// HACK(eddyb) have to bitcast pointers until LLVM removes pointee types.
// FIXME(eddyb) move these out of this `match` arm, so they're always
// applied, uniformly, no matter the source/destination types.
(
bx.bitcast(lldata, bx.cx().scalar_pair_element_backend_type(dst_layout, 0, true)),
bx.bitcast(llextra, bx.cx().scalar_pair_element_backend_type(dst_layout, 1, true)),
)
}
_ => bug!("unsize_thin_ptr: called on bad types"),
}
}
/// 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) => {
// fat-ptr to fat-ptr unsize preserves the vtable
// i.e., &'a fmt::Debug+Send => &'a fmt::Debug
// So we need to pointercast the base to ensure
// the types match up.
// FIXME(eddyb) use `scalar_pair_element_backend_type` here,
// like `unsize_thin_ptr` does.
let thin_ptr = dst.layout.field(bx.cx(), FAT_PTR_ADDR);
(bx.pointercast(base, bx.cx().backend_type(thin_ptr)), info)
}
OperandValue::Immediate(base) => unsize_thin_ptr(bx, base, src_ty, dst_ty),
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 0..def_a.variants[VariantIdx::new(0)].fields.len() {
let src_f = src.project_field(bx, i);
let dst_f = dst.project_field(bx, i);
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,
op: hir::BinOpKind,
lhs: Bx::Value,
rhs: Bx::Value,
) -> Bx::Value {
cast_shift_rhs(bx, op, lhs, rhs)
}
fn cast_shift_rhs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
op: hir::BinOpKind,
lhs: Bx::Value,
rhs: Bx::Value,
) -> Bx::Value {
// Shifts may have any size int on the rhs
if op.is_shift() {
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
}
} 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.target.options.is_like_msvc
}
pub fn from_immediate<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
val: Bx::Value,
) -> Bx::Value {
if bx.cx().val_ty(val) == bx.cx().type_i1() { bx.zext(val, bx.cx().type_i8()) } else { val }
}
pub fn to_immediate<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
val: Bx::Value,
layout: layout::TyAndLayout<'_>,
) -> Bx::Value {
if let Abi::Scalar(ref scalar) = layout.abi {
return to_immediate_scalar(bx, val, scalar);
}
val
}
pub fn to_immediate_scalar<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
val: Bx::Value,
scalar: &Scalar,
) -> Bx::Value {
if scalar.is_bool() {
return bx.trunc(val, bx.cx().type_i1());
}
val
}
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, span) = match cx.tcx().entry_fn(LOCAL_CRATE) {
Some((def_id, _)) => (def_id, cx.tcx().def_span(def_id)),
None => return None,
};
let instance = Instance::mono(cx.tcx(), main_def_id.to_def_id());
if !cx.codegen_unit().contains_item(&MonoItem::Fn(instance)) {
// We want to create the wrapper in the same codegen unit as Rust's main
// function.
return None;
}
let main_llfn = cx.get_fn_addr(instance);
return cx.tcx().entry_fn(LOCAL_CRATE).map(|(_, et)| {
let use_start_lang_item = EntryFnType::Start != et;
create_entry_fn::<Bx>(cx, span, main_llfn, main_def_id, use_start_lang_item)
});
fn create_entry_fn<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
cx: &'a Bx::CodegenCx,
sp: Span,
rust_main: Bx::Value,
rust_main_def_id: LocalDefId,
use_start_lang_item: bool,
) -> 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.target.options.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).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().erase_regions(&main_ret_ty.no_bound_vars().unwrap());
if cx.get_declared_value("main").is_some() {
// FIXME: We should be smart and show a better diagnostic here.
cx.sess()
.struct_span_err(sp, "entry symbol `main` declared multiple times")
.help("did you use `#[no_mangle]` on `fn main`? Use `#[start]` instead")
.emit();
cx.sess().abort_if_errors();
bug!();
}
let llfn = cx.declare_cfn("main", llfty);
// `main` should respect same config for frame pointer elimination as rest of code
cx.set_frame_pointer_elimination(llfn);
cx.apply_target_cpu_attr(llfn);
let mut bx = Bx::new_block(&cx, llfn, "top");
bx.insert_reference_to_gdb_debug_scripts_section_global();
let (arg_argc, arg_argv) = get_argc_argv(cx, &mut bx);
let (start_fn, args) = if use_start_lang_item {
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().intern_substs(&[main_ret_ty.into()]),
)
.unwrap()
.unwrap(),
);
(
start_fn,
vec![bx.pointercast(rust_main, cx.type_ptr_to(cx.type_i8p())), arg_argc, arg_argv],
)
} else {
debug!("using user-defined start fn");
(rust_main, vec![arg_argc, arg_argv])
};
let result = bx.call(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.target.options.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)
}
}
pub const CODEGEN_WORKER_ID: usize = usize::MAX;
pub fn codegen_crate<B: ExtraBackendMethods>(
backend: B,
tcx: TyCtxt<'tcx>,
metadata: EncodedMetadata,
need_metadata_module: bool,
) -> OngoingCodegen<B> {
// Skip crate items and just output metadata in -Z no-codegen mode.
if tcx.sess.opts.debugging_opts.no_codegen || !tcx.sess.opts.output_types.should_codegen() {
let ongoing_codegen = start_async_codegen(backend, tcx, metadata, 1);
ongoing_codegen.codegen_finished(tcx);
finalize_tcx(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(LOCAL_CRATE).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 ongoing_codegen = start_async_codegen(backend.clone(), tcx, metadata, codegen_units.len());
let ongoing_codegen = AbortCodegenOnDrop::<B>(Some(ongoing_codegen));
// Codegen an allocator shim, if necessary.
//
// 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(LOCAL_CRATE).iter().any(|(_, list)| {
use rustc_middle::middle::dependency_format::Linkage;
list.iter().any(|&linkage| linkage == Linkage::Dynamic)
});
let allocator_module = if any_dynamic_crate {
None
} else if let Some(kind) = tcx.allocator_kind() {
let llmod_id =
cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("allocator")).to_string();
let mut modules = backend.new_metadata(tcx, &llmod_id);
tcx.sess
.time("write_allocator_module", || backend.codegen_allocator(tcx, &mut modules, kind));
Some(ModuleCodegen { name: llmod_id, module_llvm: modules, kind: ModuleKind::Allocator })
} else {
None
};
if let Some(allocator_module) = allocator_module {
ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, allocator_module);
}
if need_metadata_module {
// Codegen the encoded metadata.
let metadata_cgu_name =
cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("metadata")).to_string();
let mut metadata_llvm_module = backend.new_metadata(tcx, &metadata_cgu_name);
tcx.sess.time("write_compressed_metadata", || {
backend.write_compressed_metadata(
tcx,
&ongoing_codegen.metadata,
&mut metadata_llvm_module,
);
});
let metadata_module = ModuleCodegen {
name: metadata_cgu_name,
module_llvm: metadata_llvm_module,
kind: ModuleKind::Metadata,
};
ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, metadata_module);
}
// We sort the codegen units by size. This way we can schedule work for LLVM
// a bit more efficiently.
let codegen_units = {
let mut codegen_units = codegen_units.iter().collect::<Vec<_>>();
codegen_units.sort_by_cached_key(|cgu| cmp::Reverse(cgu.size_estimate()));
codegen_units
};
let total_codegen_time = Lock::new(Duration::new(0, 0));
// 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 pre_compile_cgus = |cgu_reuse: &[CguReuse]| {
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.
par_iter(cgus)
.map(|(i, _)| {
let start_time = Instant::now();
let module = backend.compile_codegen_unit(tcx, codegen_units[i].name());
let mut time = total_codegen_time.lock();
*time += start_time.elapsed();
(i, module)
})
.collect()
})
} else {
FxHashMap::default()
}
};
let mut cgu_reuse = Vec::new();
let mut pre_compiled_cgus: Option<FxHashMap<usize, _>> = None;
for (i, cgu) in codegen_units.iter().enumerate() {
ongoing_codegen.wait_for_signal_to_codegen_item();
ongoing_codegen.check_for_errors(tcx.sess);
// Do some setup work in the first iteration
if pre_compiled_cgus.is_none() {
// Calculate the CGU reuse
cgu_reuse = tcx.sess.time("find_cgu_reuse", || {
codegen_units.iter().map(|cgu| determine_cgu_reuse(tcx, &cgu)).collect()
});
// Pre compile some CGUs
pre_compiled_cgus = Some(pre_compile_cgus(&cgu_reuse));
}
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.as_mut().unwrap().remove(&i) {
cgu
} else {
let start_time = Instant::now();
let module = backend.compile_codegen_unit(tcx, cgu.name());
let mut time = total_codegen_time.lock();
*time += start_time.elapsed();
module
};
submit_codegened_module_to_llvm(
&backend,
&ongoing_codegen.coordinator_send,
module,
cost,
);
false
}
CguReuse::PreLto => {
submit_pre_lto_module_to_llvm(
&backend,
tcx,
&ongoing_codegen.coordinator_send,
CachedModuleCodegen {
name: cgu.name().to_string(),
source: cgu.work_product(tcx),
},
);
true
}
CguReuse::PostLto => {
submit_post_lto_module_to_llvm(
&backend,
&ongoing_codegen.coordinator_send,
CachedModuleCodegen {
name: cgu.name().to_string(),
source: cgu.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.
print_time_passes_entry(
tcx.sess.time_passes(),
"codegen_to_LLVM_IR",
total_codegen_time.into_inner(),
);
::rustc_incremental::assert_module_sources::assert_module_sources(tcx);
symbol_names_test::report_symbol_names(tcx);
ongoing_codegen.check_for_errors(tcx.sess);
finalize_tcx(tcx);
ongoing_codegen.into_inner()
}
/// A curious wrapper structure whose only purpose is to call `codegen_aborted`
/// when it's dropped abnormally.
///
/// In the process of working on rust-lang/rust#55238 a mysterious segfault was
/// stumbled upon. The segfault was never reproduced locally, but it was
/// suspected to be related to the fact that codegen worker threads were
/// sticking around by the time the main thread was exiting, causing issues.
///
/// This structure is an attempt to fix that issue where the `codegen_aborted`
/// message will block until all workers have finished. This should ensure that
/// even if the main codegen thread panics we'll wait for pending work to
/// complete before returning from the main thread, hopefully avoiding
/// segfaults.
///
/// If you see this comment in the code, then it means that this workaround
/// worked! We may yet one day track down the mysterious cause of that
/// segfault...
struct AbortCodegenOnDrop<B: ExtraBackendMethods>(Option<OngoingCodegen<B>>);
impl<B: ExtraBackendMethods> AbortCodegenOnDrop<B> {
fn into_inner(mut self) -> OngoingCodegen<B> {
self.0.take().unwrap()
}
}
impl<B: ExtraBackendMethods> Deref for AbortCodegenOnDrop<B> {
type Target = OngoingCodegen<B>;
fn deref(&self) -> &OngoingCodegen<B> {
self.0.as_ref().unwrap()
}
}
impl<B: ExtraBackendMethods> DerefMut for AbortCodegenOnDrop<B> {
fn deref_mut(&mut self) -> &mut OngoingCodegen<B> {
self.0.as_mut().unwrap()
}
}
impl<B: ExtraBackendMethods> Drop for AbortCodegenOnDrop<B> {
fn drop(&mut self) {
if let Some(codegen) = self.0.take() {
codegen.codegen_aborted();
}
}
}
fn finalize_tcx(tcx: TyCtxt<'_>) {
tcx.sess.time("assert_dep_graph", || ::rustc_incremental::assert_dep_graph(tcx));
tcx.sess.time("serialize_dep_graph", || ::rustc_incremental::save_dep_graph(tcx));
// We assume that no queries are run past here. If there are new queries
// after this point, they'll show up as "<unknown>" in self-profiling data.
{
let _prof_timer = tcx.prof.generic_activity("self_profile_alloc_query_strings");
tcx.alloc_self_profile_query_strings();
}
}
impl CrateInfo {
pub fn new(tcx: TyCtxt<'_>) -> CrateInfo {
let mut info = CrateInfo {
panic_runtime: None,
compiler_builtins: None,
profiler_runtime: None,
is_no_builtins: Default::default(),
native_libraries: Default::default(),
used_libraries: tcx.native_libraries(LOCAL_CRATE),
link_args: tcx.link_args(LOCAL_CRATE),
crate_name: Default::default(),
used_crates_dynamic: cstore::used_crates(tcx, LinkagePreference::RequireDynamic),
used_crates_static: cstore::used_crates(tcx, LinkagePreference::RequireStatic),
used_crate_source: Default::default(),
lang_item_to_crate: Default::default(),
missing_lang_items: Default::default(),
dependency_formats: tcx.dependency_formats(LOCAL_CRATE),
};
let lang_items = tcx.lang_items();
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);
info.missing_lang_items.reserve(n_crates);
for &cnum in crates.iter() {
info.native_libraries.insert(cnum, tcx.native_libraries(cnum));
info.crate_name.insert(cnum, tcx.crate_name(cnum).to_string());
info.used_crate_source.insert(cnum, tcx.used_crate_source(cnum));
if tcx.is_panic_runtime(cnum) {
info.panic_runtime = Some(cnum);
}
if tcx.is_compiler_builtins(cnum) {
info.compiler_builtins = Some(cnum);
}
if tcx.is_profiler_runtime(cnum) {
info.profiler_runtime = Some(cnum);
}
if tcx.is_no_builtins(cnum) {
info.is_no_builtins.insert(cnum);
}
let missing = tcx.missing_lang_items(cnum);
for &item in missing.iter() {
if let Ok(id) = lang_items.require(item) {
info.lang_item_to_crate.insert(item, id.krate);
}
}
// No need to look for lang items that don't actually need to exist.
let missing =
missing.iter().cloned().filter(|&l| lang_items::required(tcx, l)).collect();
info.missing_lang_items.insert(cnum, missing);
}
info
}
}
pub fn provide_both(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, we’d 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);
for id in &*defids {
let CodegenFnAttrs { optimize, .. } = tcx.codegen_fn_attrs(*id);
match optimize {
attr::OptimizeAttr::None => continue,
attr::OptimizeAttr::Size => continue,
attr::OptimizeAttr::Speed => {
return for_speed;
}
}
}
tcx.sess.opts.optimize
};
providers.dllimport_foreign_items = |tcx, krate| {
let module_map = tcx.foreign_modules(krate);
let module_map =
module_map.iter().map(|lib| (lib.def_id, lib)).collect::<FxHashMap<_, _>>();
let dllimports = tcx
.native_libraries(krate)
.iter()
.filter(|lib| {
if !matches!(lib.kind, NativeLibKind::Dylib | NativeLibKind::Unspecified) {
return false;
}
let cfg = match lib.cfg {
Some(ref cfg) => cfg,
None => return true,
};
attr::cfg_matches(cfg, &tcx.sess.parse_sess, None)
})
.filter_map(|lib| lib.foreign_module)
.map(|id| &module_map[&id])
.flat_map(|module| module.foreign_items.iter().cloned())
.collect();
dllimports
};
providers.is_dllimport_foreign_item =
|tcx, def_id| tcx.dllimport_foreign_items(def_id.krate).contains(&def_id);
}
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.dep_graph.try_mark_green(tcx, &dep_node).is_some() {
// 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
}
}