Skip post-mono opts on mono bodies

Author: saethlin

compiler/rustc_mir_transform/src/lib.rs

@@ -25,10 +25,11 @@ use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind};
 use rustc_hir::def_id::LocalDefId;
 use rustc_index::IndexVec;
+use rustc_middle::mir::visit::Visitor;
 use rustc_middle::mir::{
     AnalysisPhase, Body, CallSource, ClearCrossCrate, ConstOperand, ConstQualifs, LocalDecl,
-    MirPhase, Operand, Place, ProjectionElem, Promoted, RuntimePhase, Rvalue, START_BLOCK,
-    SourceInfo, Statement, StatementKind, TerminatorKind,
+    Location, MirPhase, NullOp, Operand, Place, ProjectionElem, Promoted, RuntimePhase, Rvalue,
+    START_BLOCK, SourceInfo, Statement, StatementKind, TerminatorKind,
 };
 use rustc_middle::ty::{self, Instance, TyCtxt, TypeVisitableExt};
 use rustc_middle::util::Providers;
@@ -793,49 +794,37 @@ fn inner_optimized_mir(tcx: TyCtxt<'_>, did: LocalDefId) -> Body<'_> {
 
     run_optimization_passes(tcx, &mut body);
 
-    let mut vis = MonoCompatVisitor { contains_alias: false, contains_ubcheck: false };
+    let mut vis = MonoCompatVisitor { contains_ubcheck: false };
     vis.visit_body(&body);
 
     // If the MIR is already monomorphic, we can transform it to codegen MIR right away.
     if !tcx.generics_of(did).requires_monomorphization(tcx)
         && !vis.contains_ubcheck
-        && !vis.contains_alias
+        && !body.has_aliases()
     {
         let instance = Instance::mono(tcx, did.into());
         body = instance.instantiate_mir_and_normalize_erasing_regions(
             tcx,
             ty::TypingEnv::fully_monomorphized(),
             ty::EarlyBinder::bind(body),
         );
-        transform_to_codegen_mir(tcx, &mut body);
+
+        // Monomoprhizing this body didn't reveal any new information that is useful for
+        // optimizations, so we just run passes that make the MIR ready for codegen backends.
+        pm::run_passes_no_validate(tcx, &mut body, &[&add_call_guards::CriticalCallEdges], None);
     }
 
     body
 }
 
-use rustc_middle::mir::visit::{TyContext, Visitor};
-use rustc_middle::mir::{Location, NullOp};
-use rustc_middle::ty::{Ty, TypeFlags};
-
 // FIXME: This visitor looks for properties of MIR that would forbid using optimized MIR as codegen
 // MIR.
-// Currently, it looks for NullOp::UbChecks because that must be resolved at codegen, and also for
-// type projections because those are the only way I've found to realize that we are generating MIR
-// for a body with an unsatisafiable predicate. Such bodies cannot be normalized, so we must not
-// try to create codegen MIR for them.
+// Currently, it looks for NullOp::UbChecks because that must be resolved at codegen.
 struct MonoCompatVisitor {
-    contains_alias: bool,
     contains_ubcheck: bool,
 }
 
 impl<'tcx> Visitor<'tcx> for MonoCompatVisitor {
-    fn visit_ty(&mut self, ty: Ty<'tcx>, _: TyContext) {
-        debug!("{:?} {:?}", ty, ty.flags());
-        if ty.has_aliases() || ty.flags().contains(TypeFlags::HAS_TY_PROJECTION) {
-            self.contains_alias = true;
-        }
-    }
-
     fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
         if let Rvalue::NullaryOp(NullOp::UbChecks, _) = rvalue {
             self.contains_ubcheck = true;
@@ -847,13 +836,13 @@ impl<'tcx> Visitor<'tcx> for MonoCompatVisitor {
 pub fn build_codegen_mir<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> &'tcx Body<'tcx> {
     let body = tcx.instance_mir(instance.def);
 
-    let mut vis = MonoCompatVisitor { contains_alias: false, contains_ubcheck: false };
+    let mut vis = MonoCompatVisitor { contains_ubcheck: false };
     vis.visit_body(&body);
 
     // MIR for monomorphic defs has already been fully optimized in optimized_mir.
     let body = if instance.args.non_erasable_generics().next().is_some()
         || vis.contains_ubcheck
-        || vis.contains_alias
+        || body.has_aliases()
     {
         let mut body = instance.instantiate_mir_and_normalize_erasing_regions(
             tcx,

tests/codegen/issues/issue-122600-ptr-discriminant-update.rs

@@ -3,8 +3,9 @@
 #![crate_type = "lib"]
 
 // The bug here was that it was loading and storing the whole value.
-// It's ok to load the discriminant so that we preserve the UB from
-// `unreachable_unchecked`, but it must only store the constant discriminant of `B`.
+// It's ok for it to load the discriminant,
+// to preserve the UB from `unreachable_unchecked`,
+// but it better only store the constant discriminant of `B`.
 
 pub enum State {
     A([u8; 753]),
@@ -22,7 +23,7 @@ pub unsafe fn update(s: *mut State) {
     // CHECK-NOT: 75{{3|4}}
 
     // CHECK: %[[TAG:.+]] = load i8, ptr %s, align 1
-    // CHECK-NEXT: and i8 %[[TAG]], 1
+    // CHECK-NEXT: trunc nuw i8 %[[TAG]] to i1
 
     // CHECK-NOT: load
     // CHECK-NOT: store

tests/codegen/sanitizer/kcfi/emit-type-metadata-trait-objects.rs

@@ -136,7 +136,7 @@ pub fn foo5(a: &dyn Trait5<Type5, 32>) {
     let b = &[Type5; 32];
     a.quux(&b);
     // CHECK-LABEL: define{{.*}}4foo5{{.*}}!{{<unknown kind #36>|kcfi_type}} !{{[0-9]+}}
-    // CHECK:       call void %{{[0-9]}}(ptr align 1 {{%[a-z](\.0)*|%_[0-9]+]}}, ptr align 1 {{%[a-z](\.0)*|%[0-9]+}}){{.*}}[ "kcfi"(i32 [[TYPE5:[[:print:]]+]]) ]
+    // CHECK:       call void %{{[0-9]}}(ptr align 1 {{%[a-z](\.0)*|%_[0-9]+]}}, ptr align 1 {{%[a-z](\.0)*|%_[0-9]+}}){{.*}}[ "kcfi"(i32 [[TYPE5:[[:print:]]+]]) ]
 }
 
 pub fn bar5() {
@@ -145,7 +145,7 @@ pub fn bar5() {
     let b = &a as &dyn Trait5<Type5, 32>;
     b.quux(&a);
     // CHECK-LABEL: define{{.*}}4bar5{{.*}}!{{<unknown kind #36>|kcfi_type}} !{{[0-9]+}}
-    // CHECK:       call void %{{[0-9]}}(ptr align 1 {{%[a-z](\.0)*|%_[0-9]+]}}, ptr align 1 {{%[a-z](\.0)*|%[0-9]+}}){{.*}}[ "kcfi"(i32 [[TYPE5:[[:print:]]+]]) ]
+    // CHECK:       call void %{{[0-9]}}(ptr align 1 {{%[a-z](\.0)*|%_[0-9]+]}}, ptr align 1 {{%[a-z](\.0)*|%_[0-9]+}}){{.*}}[ "kcfi"(i32 [[TYPE5:[[:print:]]+]]) ]
 }
 
 // CHECK: !{{[0-9]+}} = !{i32 [[TYPE1]]}

tests/coverage/issue-84561.cov-map

@@ -59,19 +59,20 @@ Number of file 0 mappings: 1
 Highest counter ID seen: c0
 
 Function name: issue_84561::test3
-Raw bytes (277): 0x[01, 01, 09, 0d, 11, 0d, 15, 0d, 19, 1d, 21, 25, 29, 25, 29, 25, 29, 25, 29, 25, 2d, 33, 01, 08, 01, 03, 0f, 05, 04, 09, 01, 0f, 09, 02, 05, 04, 0f, 09, 05, 05, 00, 0f, 09, 01, 05, 00, 0f, 09, 01, 09, 01, 0f, 0d, 02, 05, 00, 0f, 0d, 01, 05, 00, 0f, 00, 00, 20, 00, 30, 0d, 01, 05, 03, 0f, 00, 03, 20, 00, 30, 00, 00, 33, 00, 41, 00, 00, 4b, 00, 5a, 0d, 01, 05, 00, 0f, 00, 05, 09, 03, 10, 00, 05, 0d, 00, 1b, 00, 02, 0d, 00, 1c, 0d, 04, 09, 02, 0f, 0d, 06, 05, 00, 0f, 0d, 04, 05, 00, 0f, 0d, 04, 09, 01, 0f, 0d, 05, 08, 00, 0f, 11, 01, 09, 00, 13, 02, 05, 09, 00, 13, 0d, 05, 08, 00, 0f, 15, 01, 09, 00, 13, 00, 03, 0d, 00, 1d, 06, 03, 09, 00, 13, 00, 03, 0d, 00, 1d, 0d, 03, 05, 00, 0f, 0d, 01, 0c, 00, 13, 19, 01, 0d, 00, 13, 0a, 02, 0d, 00, 13, 1d, 04, 05, 02, 13, 21, 03, 0d, 00, 13, 0e, 02, 0d, 00, 13, 25, 03, 05, 00, 0f, 25, 01, 0c, 00, 13, 29, 01, 0d, 00, 17, 29, 04, 0d, 00, 13, 1e, 02, 0d, 00, 17, 1e, 01, 14, 00, 1b, 00, 01, 15, 00, 1b, 1e, 02, 15, 00, 1b, 1e, 04, 0d, 00, 13, 22, 03, 09, 00, 19, 2d, 02, 05, 00, 0f, 2d, 03, 09, 00, 22, 00, 02, 05, 00, 0f, 00, 03, 09, 00, 2c, 00, 02, 01, 00, 02]
+Raw bytes (279): 0x[01, 01, 0a, 0d, 11, 0d, 15, 0d, 19, 1d, 21, 29, 2d, 25, 29, 25, 29, 25, 29, 27, 31, 29, 2d, 33, 01, 08, 01, 03, 0f, 05, 04, 09, 01, 0f, 09, 02, 05, 04, 0f, 09, 05, 05, 00, 0f, 09, 01, 05, 00, 0f, 09, 01, 09, 01, 0f, 0d, 02, 05, 00, 0f, 0d, 01, 05, 00, 0f, 00, 00, 20, 00, 30, 0d, 01, 05, 03, 0f, 00, 03, 20, 00, 30, 00, 00, 33, 00, 41, 00, 00, 4b, 00, 5a, 0d, 01, 05, 00, 0f, 00, 05, 09, 03, 10, 00, 05, 0d, 00, 1b, 00, 02, 0d, 00, 1c, 0d, 04, 09, 02, 0f, 0d, 06, 05, 00, 0f, 0d, 04, 05, 00, 0f, 0d, 04, 09, 01, 0f, 0d, 05, 08, 00, 0f, 11, 01, 09, 00, 13, 02, 05, 09, 00, 13, 0d, 05, 08, 00, 0f, 15, 01, 09, 00, 13, 00, 03, 0d, 00, 1d, 06, 03, 09, 00, 13, 00, 03, 0d, 00, 1d, 0d, 03, 05, 00, 0f, 0d, 01, 0c, 00, 13, 19, 01, 0d, 00, 13, 0a, 02, 0d, 00, 13, 1d, 04, 05, 02, 13, 21, 03, 0d, 00, 13, 0e, 02, 0d, 00, 13, 27, 03, 05, 00, 0f, 25, 01, 0c, 00, 13, 29, 01, 0d, 00, 17, 29, 04, 0d, 00, 13, 1e, 02, 0d, 00, 17, 1e, 01, 14, 00, 1b, 00, 01, 15, 00, 1b, 1e, 02, 15, 00, 1b, 2d, 04, 0d, 00, 13, 22, 03, 09, 00, 19, 31, 02, 05, 00, 0f, 31, 03, 09, 00, 22, 00, 02, 05, 00, 0f, 00, 03, 09, 00, 2c, 00, 02, 01, 00, 02]
 Number of files: 1
 - file 0 => global file 1
-Number of expressions: 9
+Number of expressions: 10
 - expression 0 operands: lhs = Counter(3), rhs = Counter(4)
 - expression 1 operands: lhs = Counter(3), rhs = Counter(5)
 - expression 2 operands: lhs = Counter(3), rhs = Counter(6)
 - expression 3 operands: lhs = Counter(7), rhs = Counter(8)
-- expression 4 operands: lhs = Counter(9), rhs = Counter(10)
+- expression 4 operands: lhs = Counter(10), rhs = Counter(11)
 - expression 5 operands: lhs = Counter(9), rhs = Counter(10)
 - expression 6 operands: lhs = Counter(9), rhs = Counter(10)
 - expression 7 operands: lhs = Counter(9), rhs = Counter(10)
-- expression 8 operands: lhs = Counter(9), rhs = Counter(11)
+- expression 8 operands: lhs = Expression(9, Add), rhs = Counter(12)
+- expression 9 operands: lhs = Counter(10), rhs = Counter(11)
 Number of file 0 mappings: 51
 - Code(Counter(0)) at (prev + 8, 1) to (start + 3, 15)
 - Code(Counter(1)) at (prev + 4, 9) to (start + 1, 15)
@@ -113,7 +114,8 @@ Number of file 0 mappings: 51
 - Code(Counter(8)) at (prev + 3, 13) to (start + 0, 19)
 - Code(Expression(3, Sub)) at (prev + 2, 13) to (start + 0, 19)
     = (c7 - c8)
-- Code(Counter(9)) at (prev + 3, 5) to (start + 0, 15)
+- Code(Expression(9, Add)) at (prev + 3, 5) to (start + 0, 15)
+    = (c10 + c11)
 - Code(Counter(9)) at (prev + 1, 12) to (start + 0, 19)
 - Code(Counter(10)) at (prev + 1, 13) to (start + 0, 23)
 - Code(Counter(10)) at (prev + 4, 13) to (start + 0, 19)
@@ -124,14 +126,13 @@ Number of file 0 mappings: 51
 - Code(Zero) at (prev + 1, 21) to (start + 0, 27)
 - Code(Expression(7, Sub)) at (prev + 2, 21) to (start + 0, 27)
     = (c9 - c10)
-- Code(Expression(7, Sub)) at (prev + 4, 13) to (start + 0, 19)
-    = (c9 - c10)
+- Code(Counter(11)) at (prev + 4, 13) to (start + 0, 19)
 - Code(Expression(8, Sub)) at (prev + 3, 9) to (start + 0, 25)
-    = (c9 - c11)
-- Code(Counter(11)) at (prev + 2, 5) to (start + 0, 15)
-- Code(Counter(11)) at (prev + 3, 9) to (start + 0, 34)
+    = ((c10 + c11) - c12)
+- Code(Counter(12)) at (prev + 2, 5) to (start + 0, 15)
+- Code(Counter(12)) at (prev + 3, 9) to (start + 0, 34)
 - Code(Zero) at (prev + 2, 5) to (start + 0, 15)
 - Code(Zero) at (prev + 3, 9) to (start + 0, 44)
 - Code(Zero) at (prev + 2, 1) to (start + 0, 2)
-Highest counter ID seen: c11
+Highest counter ID seen: c12