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[AutoDiff] Fix PullbackCloner tangent value category mismatch crash #33512

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Merged
merged 1 commit into from
Aug 18, 2020
Merged

[AutoDiff] Fix PullbackCloner tangent value category mismatch crash #33512

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1 change: 1 addition & 0 deletions lib/SIL/IR/SILFunctionType.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -407,6 +407,7 @@ static CanSILFunctionType getAutoDiffDifferentialType(
// result's convention is indirect.
if (tl.isAddressOnly() && !isIndirectFormalResult(origResConv)) {
switch (origResConv) {
case ResultConvention::Unowned:
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Note: we could make this logic handle all ResultConvention cases.

But with this change, the three common ResultConvention cases are all handed (Unowned, Owned, Indirect). I haven't seen the other cases (UnownedInnerPointer, Autoreleased) appear in practice.

case ResultConvention::Owned:
return ResultConvention::Indirect;
default:
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4 changes: 2 additions & 2 deletions lib/SILOptimizer/Differentiation/PullbackCloner.cpp
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Expand Up @@ -2431,7 +2431,7 @@ bool PullbackCloner::Implementation::runForSemanticMemberGetter() {

// Switch based on the base tangent struct's value category.
// TODO(TF-1255): Simplify using unified adjoint value data structure.
switch (tangentVectorSILTy.getCategory()) {
switch (getTangentValueCategory(origSelf)) {
case SILValueCategory::Object: {
auto adjResult = getAdjointValue(origEntry, origResult);
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Note: hypothetically, there may be a similar "tangent value category mismatch" hole on this line where getAdjointValue(origEntry, origResult) is called before checking that getTangentValueCategory(origResult) == SILValueCategory::Object.

I can't think of a trigger for this in practice (semantic member getter pullback generation for origSelf with object tangent value category but origResult with address tangent value category), so I think it's fine to skip it for now.

switch (adjResult.getKind()) {
Expand Down Expand Up @@ -2472,7 +2472,7 @@ bool PullbackCloner::Implementation::runForSemanticMemberGetter() {
if (field == tanField) {
// Switch based on the property's value category.
// TODO(TF-1255): Simplify using unified adjoint value data structure.
switch (origResult->getType().getCategory()) {
switch (getTangentValueCategory(origResult)) {
case SILValueCategory::Object: {
auto adjResult = getAdjointValue(origEntry, origResult);
auto adjResultValue = materializeAdjointDirect(adjResult, pbLoc);
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12 changes: 12 additions & 0 deletions test/AutoDiff/compiler_crashers_fixed/sr13411-tangent-value-category-mismatch.swift
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@@ -0,0 +1,12 @@
// RUN: %target-build-swift %s
// REQUIRES: asserts

// SR-13411: Semantic member getter pullback generation crash due to tangent value category mismatch

import _Differentiation

struct Dense: Differentiable {
@differentiable
var bias: Float?
}