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Rollup merge of #78966 - tmiasko:inline-never, r=oli-obk

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Never inline C variadics, cold functions, functions with incompatible attributes ...

... and fix generator inlining.

Closes #67863.
Closes #78859.
This commit is contained in:
Dylan DPC
2020-11-15 03:02:48 +01:00
committed by GitHub
parent 335a2554f9 2a010dd340
commit 6be44ed3b5
9 changed files with 238 additions and 61 deletions
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41
compiler/rustc_mir/src/transform/inline.rs
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@@ -7,6 +7,7 @@ use rustc_index::vec::Idx;
use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
use rustc_middle::mir::visit::*;
use rustc_middle::mir::*;
use rustc_middle::ty::subst::Subst;
use rustc_middle::ty::{self, ConstKind, Instance, InstanceDef, ParamEnv, Ty, TyCtxt};
use rustc_span::{hygiene::ExpnKind, ExpnData, Span};
use rustc_target::spec::abi::Abi;
@@ -28,6 +29,7 @@ pub struct Inline;
#[derive(Copy, Clone, Debug)]
struct CallSite<'tcx> {
callee: Instance<'tcx>,
fn_sig: ty::PolyFnSig<'tcx>,
block: BasicBlock,
target: Option<BasicBlock>,
source_info: SourceInfo,
@@ -173,22 +175,23 @@ impl Inliner<'tcx> {
// Only consider direct calls to functions
let terminator = bb_data.terminator();
if let TerminatorKind::Call { func: ref op, ref destination, .. } = terminator.kind {
if let ty::FnDef(callee_def_id, substs) = *op.ty(caller_body, self.tcx).kind() {
// To resolve an instance its substs have to be fully normalized, so
// we do this here.
let normalized_substs = self.tcx.normalize_erasing_regions(self.param_env, substs);
if let TerminatorKind::Call { ref func, ref destination, .. } = terminator.kind {
let func_ty = func.ty(caller_body, self.tcx);
if let ty::FnDef(def_id, substs) = *func_ty.kind() {
// To resolve an instance its substs have to be fully normalized.
let substs = self.tcx.normalize_erasing_regions(self.param_env, substs);
let callee =
Instance::resolve(self.tcx, self.param_env, callee_def_id, normalized_substs)
.ok()
.flatten()?;
Instance::resolve(self.tcx, self.param_env, def_id, substs).ok().flatten()?;
if let InstanceDef::Virtual(..) | InstanceDef::Intrinsic(_) = callee.def {
return None;
}
let fn_sig = self.tcx.fn_sig(def_id).subst(self.tcx, substs);
return Some(CallSite {
callee,
fn_sig,
block: bb,
target: destination.map(|(_, target)| target),
source_info: terminator.source_info,
@@ -203,9 +206,8 @@ impl Inliner<'tcx> {
debug!("should_inline({:?})", callsite);
let tcx = self.tcx;
// Cannot inline generators which haven't been transformed yet
if callee_body.yield_ty.is_some() {
debug!(" yield ty present - not inlining");
if callsite.fn_sig.c_variadic() {
debug!("callee is variadic - not inlining");
return false;
}
@@ -218,11 +220,7 @@ impl Inliner<'tcx> {
return false;
}
let self_no_sanitize =
self.codegen_fn_attrs.no_sanitize & self.tcx.sess.opts.debugging_opts.sanitizer;
let callee_no_sanitize =
codegen_fn_attrs.no_sanitize & self.tcx.sess.opts.debugging_opts.sanitizer;
if self_no_sanitize != callee_no_sanitize {
if self.codegen_fn_attrs.no_sanitize != codegen_fn_attrs.no_sanitize {
debug!("`callee has incompatible no_sanitize attribute - not inlining");
return false;
}
@@ -256,9 +254,9 @@ impl Inliner<'tcx> {
self.tcx.sess.opts.debugging_opts.inline_mir_threshold
};
// Significantly lower the threshold for inlining cold functions
if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::COLD) {
threshold /= 5;
debug!("#[cold] present - not inlining");
return false;
}
// Give a bonus functions with a small number of blocks,
@@ -447,7 +445,7 @@ impl Inliner<'tcx> {
};
// Copy the arguments if needed.
let args: Vec<_> = self.make_call_args(args, &callsite, caller_body);
let args: Vec<_> = self.make_call_args(args, &callsite, caller_body, &callee_body);
let mut integrator = Integrator {
args: &args,
@@ -528,6 +526,7 @@ impl Inliner<'tcx> {
args: Vec<Operand<'tcx>>,
callsite: &CallSite<'tcx>,
caller_body: &mut Body<'tcx>,
callee_body: &Body<'tcx>,
) -> Vec<Local> {
let tcx = self.tcx;
@@ -554,9 +553,7 @@ impl Inliner<'tcx> {
// tmp2 = tuple_tmp.2
//
// and the vector is `[closure_ref, tmp0, tmp1, tmp2]`.
// FIXME(eddyb) make this check for `"rust-call"` ABI combined with
// `callee_body.spread_arg == None`, instead of special-casing closures.
if tcx.is_closure(callsite.callee.def_id()) {
if callsite.fn_sig.abi() == Abi::RustCall && callee_body.spread_arg.is_none() {
let mut args = args.into_iter();
let self_ = self.create_temp_if_necessary(args.next().unwrap(), callsite, caller_body);
let tuple = self.create_temp_if_necessary(args.next().unwrap(), callsite, caller_body);