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Merged
merged 2 commits into from
Dec 6, 2023
Merged

Handle unchecked_ref_cast in ObjectOutliner #70243

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d6439b6
[NFC] Add some debugging messages to COWOpts
meg-gupta Nov 29, 2023
a228a88
Handle unchecked_ref_cast in ObjectOutliner
meg-gupta Dec 5, 2023
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10 changes: 10 additions & 0 deletions SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ObjectOutliner.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,10 @@ private func findEndCOWMutation(of object: Value) -> EndCOWMutationInst? {
if let ecm = findEndCOWMutation(of: uci) {
return ecm
}
case let urci as UncheckedRefCastInst:
if let ecm = findEndCOWMutation(of: urci) {
return ecm
}
case let mv as MoveValueInst:
if let ecm = findEndCOWMutation(of: mv) {
return ecm
Expand Down Expand Up @@ -134,6 +138,10 @@ private func findInitStores(of object: Value,
if !findInitStores(of: uci, &fieldStores, &tailStores) {
return false
}
case let urci as UncheckedRefCastInst:
if !findInitStores(of: urci, &fieldStores, &tailStores) {
return false
}
case let mvi as MoveValueInst:
if !findInitStores(of: mvi, &fieldStores, &tailStores) {
return false
Expand Down Expand Up @@ -342,6 +350,8 @@ private func rewriteUses(of startValue: Value, _ context: FunctionPassContext) {
context.erase(instruction: endMutation)
case let upCast as UpcastInst:
worklist.pushIfNotVisited(usersOf: upCast)
case let refCast as UncheckedRefCastInst:
worklist.pushIfNotVisited(usersOf: refCast)
case let moveValue as MoveValueInst:
worklist.pushIfNotVisited(usersOf: moveValue)
case is DeallocRefInst, is DeallocStackRefInst:
Expand Down
15 changes: 14 additions & 1 deletion lib/SILOptimizer/Transforms/COWOpts.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -119,6 +119,9 @@ static SILValue skipStructAndExtract(SILValue value) {
}

bool COWOptsPass::optimizeBeginCOW(BeginCOWMutationInst *BCM) {
LLVM_DEBUG(llvm::dbgs() << "Looking at: ");
LLVM_DEBUG(BCM->dump());

SILFunction *function = BCM->getFunction();
StackList<EndCOWMutationInst *> endCOWMutationInsts(function);
InstructionSet endCOWMutationsFound(function);
Expand Down Expand Up @@ -187,14 +190,20 @@ bool COWOptsPass::optimizeBeginCOW(BeginCOWMutationInst *BCM) {
// Don't immediately bail on a store instruction. Instead, remember
// it and check if it interferes with any (potential) load.
if (storeAddrsFound.insert(store->getDest())) {
LLVM_DEBUG(llvm::dbgs() << "Found store escape, record: ");
LLVM_DEBUG(inst->dump());
storeAddrs.push_back(store->getDest());
numStoresFound += 1;
}
} else {
LLVM_DEBUG(llvm::dbgs() << "Found non-store escape, bailing out: ");
LLVM_DEBUG(inst->dump());
return false;
}
}
if (inst->mayReadFromMemory()) {
LLVM_DEBUG(llvm::dbgs() << "Found a may read inst, record: ");
LLVM_DEBUG(inst->dump());
potentialLoadInsts.push_back(inst);
numLoadsFound += 1;
}
Expand Down Expand Up @@ -225,8 +234,12 @@ bool COWOptsPass::optimizeBeginCOW(BeginCOWMutationInst *BCM) {
return false;
for (SILInstruction *load : potentialLoadInsts) {
for (SILValue storeAddr : storeAddrs) {
if (!AA || AA->mayReadFromMemory(load, storeAddr))
if (!AA || AA->mayReadFromMemory(load, storeAddr)) {
LLVM_DEBUG(llvm::dbgs() << "Found a store address aliasing with a load:");
LLVM_DEBUG(load->dump());
LLVM_DEBUG(storeAddr->dump());
return false;
}
}
}
}
Expand Down
18 changes: 18 additions & 0 deletions test/SILOptimizer/objectoutliner.sil
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Expand Up @@ -127,6 +127,24 @@ bb0:
return %r : $()
}

// CHECK-LABEL: sil @outline_global_with_uncheckedrefcast :
// CHECK: global_value
// CHECK: } // end sil function 'outline_global_with_uncheckedrefcast'
sil @outline_global_with_uncheckedrefcast : $@convention(thin) () -> () {
bb0:
%0 = integer_literal $Builtin.Word, 0
%1 = integer_literal $Builtin.Int64, 1
%4 = struct $Int64 (%1 : $Builtin.Int64)
%7 = alloc_ref [tail_elems $Int64 * %0 : $Builtin.Word] $Obj
%9 = ref_element_addr %7 : $Obj, #Obj.value
store %4 to %9 : $*Int64
%10 = unchecked_ref_cast %7 : $Obj to $Base
%11 = end_cow_mutation %10 : $Base
%12 = begin_dealloc_ref %11 : $Base of %7 : $Obj
dealloc_ref %12 : $Base
%r = tuple ()
return %r : $()
}

// CHECK-LABEL: sil @outline_global_tailelems
// CHECK: [[G:%[0-9]+]] = global_value @outline_global_tailelemsTv_ : $Obj
Expand Down