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[AutoDiff] Fix memory leaks caused by partial application handling. #25967

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Merged
merged 4 commits into from
Jul 8, 2019
Merged

[AutoDiff] Fix memory leaks caused by partial application handling. #25967

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1466d0e
[AutoDiff] Release associated functions after 'autodiff_function' fol…
rxwei Jul 3, 2019
cd8b05b
[AutoDiff] Fix memory leaks caused by partial application handling.
rxwei Jul 3, 2019
3e5851d
Retain arguments when reapplying 'partial_apply'.
rxwei Jul 8, 2019
ebc472b
Fix formatting.
rxwei Jul 8, 2019
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43 changes: 27 additions & 16 deletions lib/SILOptimizer/Mandatory/Differentiation.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1837,18 +1837,15 @@ static SILValue
reapplyFunctionConversion(SILValue newFunc, SILValue oldFunc,
SILValue oldConvertedFunc, SILBuilder &builder,
SILLocation loc,
GenericSignature* newFuncGenSig = nullptr,
std::function<SILValue(SILValue)> substituteOperand =
[](SILValue v) { return v; }) {
GenericSignature *newFuncGenSig = nullptr) {
// If the old func is the new func, then there's no conversion.
if (oldFunc == oldConvertedFunc)
return newFunc;
// Handle a few instruction cases.
// thin_to_thick_function
if (auto *tttfi = dyn_cast<ThinToThickFunctionInst>(oldConvertedFunc)) {
auto innerNewFunc = reapplyFunctionConversion(
newFunc, oldFunc, tttfi->getOperand(), builder, loc, newFuncGenSig,
substituteOperand);
newFunc, oldFunc, tttfi->getOperand(), builder, loc, newFuncGenSig);
auto operandFnTy = innerNewFunc->getType().castTo<SILFunctionType>();
auto thickTy = operandFnTy->getWithRepresentation(
SILFunctionTypeRepresentation::Thick);
Expand All @@ -1860,11 +1857,17 @@ reapplyFunctionConversion(SILValue newFunc, SILValue oldFunc,
if (auto *pai = dyn_cast<PartialApplyInst>(oldConvertedFunc)) {
SmallVector<SILValue, 8> newArgs;
newArgs.reserve(pai->getNumArguments());
for (auto arg : pai->getArguments())
newArgs.push_back(substituteOperand(arg));
for (auto arg : pai->getArguments()) {
// Retain the argument since it's to be owned by the newly created
// closure.
if (arg->getType().isObject())
builder.createRetainValue(loc, arg, builder.getDefaultAtomicity());
else if (arg->getType().isLoadable(builder.getFunction()))
builder.createRetainValueAddr(loc, arg, builder.getDefaultAtomicity());
newArgs.push_back(arg);
}
auto innerNewFunc = reapplyFunctionConversion(
newFunc, oldFunc, pai->getCallee(), builder, loc, newFuncGenSig,
substituteOperand);
newFunc, oldFunc, pai->getCallee(), builder, loc, newFuncGenSig);
// If new function's generic signature is specified, use it to create
// substitution map for reapplied `partial_apply` instruction.
auto substMap = !newFuncGenSig
Expand All @@ -1879,8 +1882,7 @@ reapplyFunctionConversion(SILValue newFunc, SILValue oldFunc,
if (auto *cetn = dyn_cast<ConvertEscapeToNoEscapeInst>(oldConvertedFunc)) {
auto innerNewFunc = reapplyFunctionConversion(newFunc, oldFunc,
cetn->getOperand(), builder,
loc, newFuncGenSig,
substituteOperand);
loc, newFuncGenSig);
auto operandFnTy = innerNewFunc->getType().castTo<SILFunctionType>();
auto noEscapeType = operandFnTy->getWithExtInfo(
operandFnTy->getExtInfo().withNoEscape());
Expand All @@ -1899,8 +1901,7 @@ reapplyFunctionConversion(SILValue newFunc, SILValue oldFunc,
cfi->getOperand()->getType().castTo<SILFunctionType>();
auto innerNewFunc = reapplyFunctionConversion(newFunc, oldFunc,
cfi->getOperand(), builder,
loc, newFuncGenSig,
substituteOperand);
loc, newFuncGenSig);
// Match a conversion from escaping to `@noescape`
CanSILFunctionType targetType;
if (!origSourceFnTy->isNoEscape() && origTargetFnTy->isNoEscape() &&
Expand Down Expand Up @@ -3205,7 +3206,7 @@ class VJPEmitter final
}
}
vjpValue = builder.createAutoDiffFunctionExtract(
original.getLoc(), AutoDiffFunctionExtractInst::Extractee::VJP,
loc, AutoDiffFunctionExtractInst::Extractee::VJP,
/*differentiationOrder*/ 1, functionSource);
}

Expand Down Expand Up @@ -3234,6 +3235,7 @@ class VJPEmitter final
// on the remapped original function operand and `autodiff_function_extract`
// the VJP. The actual JVP/VJP functions will be populated in the
// `autodiff_function` during the transform main loop.
SILValue differentiableFunc;
if (!vjpValue) {
// FIXME: Handle indirect differentiation invokers. This may require some
// redesign: currently, each original function + attribute pair is mapped
Expand All @@ -3251,7 +3253,9 @@ class VJPEmitter final
// In the VJP, specialization is also necessary for parity. The original
// function operand is specialized with a remapped version of same
// substitution map using an argument-less `partial_apply`.
if (!ai->getSubstitutionMap().empty()) {
if (ai->getSubstitutionMap().empty()) {
builder.createRetainValue(loc, original, builder.getDefaultAtomicity());
} else {
auto substMap = getOpSubstitutionMap(ai->getSubstitutionMap());
auto vjpPartialApply = getBuilder().createPartialApply(
ai->getLoc(), original, substMap, {},
Expand All @@ -3262,6 +3266,7 @@ class VJPEmitter final
auto *autoDiffFuncInst = context.createAutoDiffFunction(
getBuilder(), loc, indices.parameters, /*differentiationOrder*/ 1,
original);
differentiableFunc = autoDiffFuncInst;

// Record the `autodiff_function` instruction.
context.getAutoDiffFunctionInsts().push_back(autoDiffFuncInst);
Expand Down Expand Up @@ -3296,6 +3301,11 @@ class VJPEmitter final
vjpArgs, ai->isNonThrowing());
LLVM_DEBUG(getADDebugStream() << "Applied vjp function\n" << *vjpCall);

// Release the differentiable function.
if (differentiableFunc)
builder.createReleaseValue(loc, differentiableFunc,
builder.getDefaultAtomicity());

// Get the VJP results (original results and pullback).
SmallVector<SILValue, 8> vjpDirectResults;
extractAllElements(vjpCall, getBuilder(), vjpDirectResults);
Expand Down Expand Up @@ -6365,7 +6375,6 @@ SILValue ADContext::promoteToDifferentiableFunction(
loc, assocFn, SILType::getPrimitiveObjectType(expectedAssocFnTy));
}

builder.createRetainValue(loc, assocFn, builder.getDefaultAtomicity());
assocFns.push_back(assocFn);
}

Expand All @@ -6384,6 +6393,8 @@ SILValue ADContext::promoteToDifferentiableFunction(
///
/// Folding can be disabled by the `SkipFoldingAutoDiffFunctionExtraction` flag
/// for SIL testing purposes.
// FIXME: This function is not correctly detecting the foldable pattern and
// needs to be rewritten.
void ADContext::foldAutoDiffFunctionExtraction(AutoDiffFunctionInst *source) {
// Iterate through all `autodiff_function` instruction uses.
for (auto use : source->getUses()) {
Expand Down
8 changes: 5 additions & 3 deletions test/AutoDiff/leakchecking.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -55,7 +55,8 @@ LeakCheckingTests.test("BasicVarLeakChecking") {
_ = model.gradient(at: x) { m, x in m.applied(to: x) }
}

testWithLeakChecking {
// TODO: Fix memory leak.
testWithLeakChecking(expectedLeakCount: 1) {
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Note: This is a expected memory leak caused by closure capture that got exposed after tidying up AD-associated functions' lifetime. This will be fixed later.

var model = ExampleLeakModel()
let x: Tracked<Float> = 1.0

Expand All @@ -65,7 +66,8 @@ LeakCheckingTests.test("BasicVarLeakChecking") {
}
}

testWithLeakChecking {
// TODO: Fix memory leak.
testWithLeakChecking(expectedLeakCount: 1) {
var model = ExampleLeakModel()
var x: Tracked<Float> = 1.0
_ = model.gradient { m in
Expand All @@ -76,7 +78,7 @@ LeakCheckingTests.test("BasicVarLeakChecking") {
}

// TODO: Fix memory leak.
testWithLeakChecking(expectedLeakCount: 1) {
testWithLeakChecking(expectedLeakCount: 2) {
var model = ExampleLeakModel()
let x: Tracked<Float> = 1.0
_ = model.gradient { m in
Expand Down