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[SIL] Fix visitAccessedAddress @ end_borrow

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`end_borrow` instructions may end the scopes introduced by `load_borrow`
or `store_borrow` instructions, or those introduced by `begin_borrow`
whose operand's guaranteed root includes a `load_borrow`.

Previously, such scope ending instructions which end the scope
associated with a borrowing load or store were not regarded as accessing
the loaded-from or stored-to address.  One consequence of this is that
they were not regarded as accessing pointers and thus not as deinit
barriers; that in turn resulted in `destroy_addr`s being hoisted into
such borrow scopes.

Here this is fixed by regarding such `end_borrow`s to access the
loaded-from or stored-to address of the scope-introducing `load_borrow`
or `store_borrow` respectively.

rdar://157772187
This commit is contained in:
Nate Chandler
2025-08-11 08:13:44 -07:00
parent 573607ff36
commit 66a9b77835
2 changed files with 41 additions and 1 deletions
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18
lib/SIL/Utils/MemAccessUtils.cpp
View File

@@ -2796,6 +2796,23 @@ void swift::visitAccessedAddress(SILInstruction *I,
visitor(singleOperand);
return;
}
case SILInstructionKind::EndBorrowInst: {
auto *ebi = cast<EndBorrowInst>(I);
SmallVector<SILValue, 4> roots;
findGuaranteedReferenceRoots(ebi->getOperand(),
/*lookThroughNestedBorrows=*/true, roots);
for (auto root : roots) {
if (auto *lbi = dyn_cast<LoadBorrowInst>(root)) {
visitor(&lbi->getOperandRef());
return;
}
if (auto *sbi = dyn_cast<StoreBorrowInst>(root)) {
visitor(&sbi->getOperandRef(StoreInst::Dest));
return;
}
}
break;
}
// Non-access cases: these are marked with memory side effects, but, by
// themselves, do not access formal memory.
#define UNCHECKED_REF_STORAGE(Name, ...) \
@@ -2828,7 +2845,6 @@ void swift::visitAccessedAddress(SILInstruction *I,
case SILInstructionKind::DropDeinitInst:
case SILInstructionKind::EndAccessInst:
case SILInstructionKind::EndApplyInst:
case SILInstructionKind::EndBorrowInst:
case SILInstructionKind::EndUnpairedAccessInst:
case SILInstructionKind::EndLifetimeInst:
case SILInstructionKind::ExistentialMetatypeInst:

24
test/SILOptimizer/hoist_destroy_addr.sil
View File

@@ -84,6 +84,10 @@ struct STXXITXXII {
struct MoS: ~Copyable {}
struct MoE: ~Copyable {}
struct UnsafeMutablePointer<T> {
var _rawValue: Builtin.RawPointer
}
sil @unknown : $@convention(thin) () -> ()
sil @use_S : $@convention(thin) (@in_guaranteed S) -> ()
@@ -1346,3 +1350,23 @@ entry(%c_addr : $*X):
%retval = tuple ()
return %retval
}
// CHECK-LABEL: sil [ossa] @no_hoist_into_load_borrow_scope : {{.*}} {
// CHECK: end_borrow
// CHECK-NEXT: destroy_addr
// CHECK-LABEL: } // end sil function 'no_hoist_into_load_borrow_scope'
sil [ossa] @no_hoist_into_load_borrow_scope : $@convention(thin) (@in X) -> () {
entry(%c_addr_in : $*X):
%c_ptr = address_to_pointer [stack_protection] %c_addr_in to $Builtin.RawPointer
%c_up = struct $UnsafeMutablePointer<X> (%c_ptr)
%c_ptr_2 = struct_extract %c_up, #UnsafeMutablePointer._rawValue // user: %45
%c_addr = pointer_to_address %c_ptr_2 to [strict] $*X
%c_borrow = load_borrow %c_addr
apply undef(%c_borrow) : $@convention(thin) (@guaranteed X) -> ()
%c_copy = load [copy] %c_addr_in
end_borrow %c_borrow
%retval = tuple ()
destroy_addr %c_addr_in
destroy_value %c_copy
return %retval
}