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Enable ScalarReplacementOfAggregates
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@saethlin
saethlin committed May 31, 2023
1 parent f0411ff commit 79ba7b3
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Showing 13 changed files with 313 additions and 342 deletions.
50 changes: 45 additions & 5 deletions compiler/rustc_mir_transform/src/sroa.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,23 +6,29 @@ use rustc_middle::mir::visit::*;
use rustc_middle::mir::*;
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_mir_dataflow::value_analysis::{excluded_locals, iter_fields};
use rustc_target::abi::FieldIdx;
use rustc_target::abi::{FieldIdx, ReprFlags, FIRST_VARIANT};

pub struct ScalarReplacementOfAggregates;

impl<'tcx> MirPass<'tcx> for ScalarReplacementOfAggregates {
fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
sess.mir_opt_level() >= 3
sess.mir_opt_level() >= 2
}

#[instrument(level = "debug", skip(self, tcx, body))]
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
debug!(def_id = ?body.source.def_id());

// Avoid query cycles (generators require optimized MIR for layout).
if tcx.type_of(body.source.def_id()).subst_identity().is_generator() {
return;
}

let mut excluded = excluded_locals(body);
let param_env = tcx.param_env_reveal_all_normalized(body.source.def_id());
loop {
debug!(?excluded);
let escaping = escaping_locals(&excluded, body);
let escaping = escaping_locals(tcx, param_env, &excluded, body);
debug!(?escaping);
let replacements = compute_flattening(tcx, param_env, body, escaping);
debug!(?replacements);
Expand All @@ -48,11 +54,45 @@ impl<'tcx> MirPass<'tcx> for ScalarReplacementOfAggregates {
/// - the locals is a union or an enum;
/// - the local's address is taken, and thus the relative addresses of the fields are observable to
/// client code.
fn escaping_locals(excluded: &BitSet<Local>, body: &Body<'_>) -> BitSet<Local> {
fn escaping_locals<'tcx>(
tcx: TyCtxt<'tcx>,
param_env: ty::ParamEnv<'tcx>,
excluded: &BitSet<Local>,
body: &Body<'tcx>,
) -> BitSet<Local> {
let is_excluded_ty = |ty: Ty<'tcx>| {
if ty.is_union() || ty.is_enum() {
return true;
}
if let ty::Adt(def, _substs) = ty.kind() {
if def.repr().flags.contains(ReprFlags::IS_SIMD) {
// Exclude #[repr(simd)] types so that they are not de-optimized into an array
return true;
}
// We already excluded unions and enums, so this ADT must have one variant
let variant = def.variant(FIRST_VARIANT);
if variant.fields.len() > 1 {
// If this has more than one field, it cannot be a wrapper that only provides a
// niche, so we do not want to automatically exclude it.
return false;
}
let Ok(layout) = tcx.layout_of(param_env.and(ty)) else {
// We can't get the layout
return true;
};
if layout.layout.largest_niche().is_some() {
// This type has a niche
return true;
}
}
// Default for non-ADTs
false
};

let mut set = BitSet::new_empty(body.local_decls.len());
set.insert_range(RETURN_PLACE..=Local::from_usize(body.arg_count));
for (local, decl) in body.local_decls().iter_enumerated() {
if decl.ty.is_union() || decl.ty.is_enum() || excluded.contains(local) {
if excluded.contains(local) || is_excluded_ty(decl.ty) {
set.insert(local);
}
}
Expand Down
7 changes: 4 additions & 3 deletions tests/codegen/issues/issue-105386-ub-in-debuginfo.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
// compile-flags: --crate-type=lib -O -Cdebuginfo=2 -Cno-prepopulate-passes
// compile-flags: --crate-type=lib -O -Cdebuginfo=2 -Cno-prepopulate-passes -Zmir-enable-passes=-ScalarReplacementOfAggregates
// MIR SROA will decompose the closure
// min-llvm-version: 15.0 # this test uses opaque pointer notation
#![feature(stmt_expr_attributes)]

Expand All @@ -15,8 +16,8 @@ pub fn outer_function(x: S, y: S) -> usize {
// Check that we do not attempt to load from the spilled arg before it is assigned to
// when generating debuginfo.
// CHECK-LABEL: @outer_function
// CHECK: [[spill:%.*]] = alloca %"[closure@{{.*.rs}}:9:23: 9:25]"
// CHECK-NOT: [[ptr_tmp:%.*]] = getelementptr inbounds %"[closure@{{.*.rs}}:9:23: 9:25]", ptr [[spill]]
// CHECK: [[spill:%.*]] = alloca %"[closure@{{.*.rs}}:10:23: 10:25]"
// CHECK-NOT: [[ptr_tmp:%.*]] = getelementptr inbounds %"[closure@{{.*.rs}}:10:23: 10:25]", ptr [[spill]]
// CHECK-NOT: [[load:%.*]] = load ptr, ptr
// CHECK: call void @llvm.lifetime.start{{.*}}({{.*}}, ptr [[spill]])
// CHECK: [[inner:%.*]] = getelementptr inbounds %"{{.*}}", ptr [[spill]]
Expand Down
3 changes: 2 additions & 1 deletion tests/incremental/hashes/match_expressions.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -225,8 +225,9 @@ pub fn change_mutability_of_binding_in_pattern(x: u32) -> u32 {
}
}

// Ignore optimized_mir in cfail2, the only change to optimized MIR is a span.
#[cfg(not(any(cfail1,cfail4)))]
#[rustc_clean(cfg="cfail2", except="hir_owner_nodes,optimized_mir,typeck")]
#[rustc_clean(cfg="cfail2", except="hir_owner_nodes,typeck")]
#[rustc_clean(cfg="cfail3")]
#[rustc_clean(cfg="cfail5", except="hir_owner_nodes,optimized_mir,typeck")]
#[rustc_clean(cfg="cfail6")]
Expand Down
96 changes: 44 additions & 52 deletions tests/mir-opt/inline/unchecked_shifts.unchecked_shl_unsigned_smaller.Inline.diff
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Original file line number Diff line number Diff line change
Expand Up @@ -11,35 +11,33 @@
+ debug self => _3; // in scope 1 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+ debug rhs => _4; // in scope 1 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+ let mut _5: u16; // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ let mut _6: (u32,); // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ let mut _7: u32; // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ scope 2 {
+ scope 3 (inlined core::num::<impl u16>::unchecked_shl::conv) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ debug x => _7; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ let mut _8: std::option::Option<u16>; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ let mut _9: std::result::Result<u16, std::num::TryFromIntError>; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ debug x => _4; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ let mut _6: std::option::Option<u16>; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ let mut _7: std::result::Result<u16, std::num::TryFromIntError>; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ scope 4 {
+ scope 5 (inlined <u32 as TryInto<u16>>::try_into) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ debug self => _7; // in scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
+ debug self => _4; // in scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
+ scope 6 (inlined convert::num::<impl TryFrom<u32> for u16>::try_from) { // at $SRC_DIR/core/src/convert/mod.rs:LL:COL
+ debug u => _7; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ let mut _10: bool; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ let mut _11: u32; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ let mut _12: u16; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ debug u => _4; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ let mut _8: bool; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ let mut _9: u32; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ let mut _10: u16; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ }
+ }
+ scope 7 (inlined Result::<u16, TryFromIntError>::ok) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ debug self => _9; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ let mut _13: isize; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ let _14: u16; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ debug self => _7; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ let mut _11: isize; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ let _12: u16; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ scope 8 {
+ debug x => _14; // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
+ debug x => _12; // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
+ }
+ }
+ scope 9 (inlined #[track_caller] Option::<u16>::unwrap_unchecked) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ debug self => _8; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+ let mut _15: &std::option::Option<u16>; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+ let mut _16: isize; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+ debug self => _6; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+ let mut _13: &std::option::Option<u16>; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+ let mut _14: isize; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+ scope 10 {
+ debug val => _5; // in scope 10 at $SRC_DIR/core/src/option.rs:LL:COL
+ }
Expand All @@ -52,7 +50,7 @@
+ }
+ }
+ scope 12 (inlined Option::<u16>::is_some) { // at $SRC_DIR/core/src/option.rs:LL:COL
+ debug self => _15; // in scope 12 at $SRC_DIR/core/src/option.rs:LL:COL
+ debug self => _13; // in scope 12 at $SRC_DIR/core/src/option.rs:LL:COL
+ }
+ }
+ }
Expand All @@ -70,18 +68,14 @@
- // + span: $DIR/unchecked_shifts.rs:11:7: 11:20
- // + literal: Const { ty: unsafe fn(u16, u32) -> u16 {core::num::<impl u16>::unchecked_shl}, val: Value(<ZST>) }
+ StorageLive(_5); // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageLive(_6); // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ _6 = (_4,); // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageLive(_7); // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ _7 = move (_6.0: u32); // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageLive(_8); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageLive(_9); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageLive(_10); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ StorageLive(_11); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ _11 = const 65535_u32; // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ _10 = Gt(_7, move _11); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ StorageDead(_11); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ switchInt(move _10) -> [0: bb3, otherwise: bb2]; // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ StorageLive(_6); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageLive(_7); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageLive(_8); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ StorageLive(_9); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ _9 = const 65535_u32; // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ _8 = Gt(_4, move _9); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ StorageDead(_9); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ switchInt(move _8) -> [0: bb3, otherwise: bb2]; // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
}

bb1: {
Expand All @@ -92,30 +86,30 @@
+ }
+
+ bb2: {
+ _9 = Result::<u16, TryFromIntError>::Err(const TryFromIntError(())); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ _7 = Result::<u16, TryFromIntError>::Err(const TryFromIntError(())); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ // mir::Constant
+ // + span: no-location
+ // + literal: Const { ty: TryFromIntError, val: Value(<ZST>) }
+ goto -> bb4; // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ }
+
+ bb3: {
+ StorageLive(_12); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ _12 = _7 as u16 (IntToInt); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ _9 = Result::<u16, TryFromIntError>::Ok(move _12); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ StorageDead(_12); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ StorageLive(_10); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ _10 = _4 as u16 (IntToInt); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ _7 = Result::<u16, TryFromIntError>::Ok(move _10); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ StorageDead(_10); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ goto -> bb4; // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ }
+
+ bb4: {
+ StorageDead(_10); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ StorageLive(_14); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ _13 = discriminant(_9); // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ switchInt(move _13) -> [0: bb7, 1: bb5, otherwise: bb6]; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ StorageDead(_8); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+ StorageLive(_12); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ _11 = discriminant(_7); // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ switchInt(move _11) -> [0: bb7, 1: bb5, otherwise: bb6]; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ }
+
+ bb5: {
+ _8 = Option::<u16>::None; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ _6 = Option::<u16>::None; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ goto -> bb8; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ }
+
Expand All @@ -124,25 +118,23 @@
+ }
+
+ bb7: {
+ _14 = move ((_9 as Ok).0: u16); // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ _8 = Option::<u16>::Some(move _14); // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
+ _12 = move ((_7 as Ok).0: u16); // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ _6 = Option::<u16>::Some(move _12); // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
+ goto -> bb8; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+ }
+
+ bb8: {
+ StorageDead(_14); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageDead(_9); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageLive(_15); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ _16 = discriminant(_8); // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+ switchInt(move _16) -> [1: bb9, otherwise: bb6]; // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+ StorageDead(_12); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageDead(_7); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageLive(_13); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ _14 = discriminant(_6); // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+ switchInt(move _14) -> [1: bb9, otherwise: bb6]; // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+ }
+
+ bb9: {
+ _5 = move ((_8 as Some).0: u16); // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+ StorageDead(_15); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageDead(_8); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageDead(_7); // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageDead(_6); // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ _5 = move ((_6 as Some).0: u16); // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+ StorageDead(_13); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ StorageDead(_6); // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+ _0 = unchecked_shl::<u16>(_3, move _5) -> [return: bb1, unwind unreachable]; // scope 2 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+ // mir::Constant
+ // + span: $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
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