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[AutoDiff] TF-1046: put gen sig in more places #28735

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Merged
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Dec 12, 2019
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[AutoDiff] TF-1046: put gen sig in more places #28735

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21 changes: 15 additions & 6 deletions lib/SIL/SILDeclRef.cpp
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Expand Up @@ -949,13 +949,22 @@ SILDeclRef SILDeclRef::getNextOverriddenVTableEntry() const {
if (autoDiffDerivativeFunctionIdentifier) {
auto overriddenAttrs =
overridden.getDecl()->getAttrs().getAttributes<DifferentiableAttr>();
if (llvm::none_of(overriddenAttrs, [&](const DifferentiableAttr *attr) {
return attr->getParameterIndices() ==
autoDiffDerivativeFunctionIdentifier->getParameterIndices();
})) {
return SILDeclRef();
for (const auto *attr : overriddenAttrs) {
if (attr->getParameterIndices() !=
autoDiffDerivativeFunctionIdentifier->getParameterIndices())
continue;

// TODO(TF-1056): Do we need to check generic signature requirements?

auto dfi = overridden.autoDiffDerivativeFunctionIdentifier;
overridden.autoDiffDerivativeFunctionIdentifier =
AutoDiffDerivativeFunctionIdentifier::get(
dfi->getKind(), dfi->getParameterIndices(),
attr->getDerivativeGenericSignature(),
getDecl()->getASTContext());
return overridden;
}
return overridden;
return SILDeclRef();
}
// SWIFT_ENABLE_TENSORFLOW END
return overridden;
Expand Down
3 changes: 3 additions & 0 deletions lib/SILGen/SILGen.cpp
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Expand Up @@ -774,6 +774,9 @@ void SILGenModule::postEmitFunction(SILDeclRef constant,
if (auto *vjpDecl = diffAttr->getVJPFunction())
vjp = getFunction(SILDeclRef(vjpDecl), NotForDefinition);
auto *resultIndices = IndexSubset::get(getASTContext(), 1, {0});
assert((!AFD->getGenericSignature() || diffAttr->getDerivativeGenericSignature()) &&
"type-checking should resolve derivative generic signatures for "
"all functions with generic signatures");
AutoDiffConfig config(diffAttr->getParameterIndices(), resultIndices,
diffAttr->getDerivativeGenericSignature());
emitDifferentiabilityWitness(AFD, F, config, jvp, vjp, diffAttr);
Expand Down
16 changes: 14 additions & 2 deletions lib/SILOptimizer/Mandatory/Differentiation.cpp
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Expand Up @@ -237,10 +237,20 @@ static bool diagnoseUnsupportedControlFlow(ADContext &context,
/// derivative generic signature (containing requirements), and substitution
/// map. Returns true if error is emitted.
static bool diagnoseUnsatisfiedRequirements(ADContext &context,
CanSILFunctionType origFnTy,
GenericSignature derivativeGenSig,
SubstitutionMap substMap,
DifferentiationInvoker invoker,
SourceLoc loc) {
// If the original function is polymorphic and its generic signature is the
// same as the derivative generic signature, then the requirements are
// satisfied. This check is necessary because the subsequent logic does not
// correctly handle polymorphic original functions.
// TODO(TF-1055): Can be removed after we have a robust solution for TF-1055.
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I wonder what's the specific symptom of TF-1055?

Referencing the example:

sil_differentiability_witness @foo <T: A> { ... }

sil_differentiability_witness @foo <T: B> { ... }

sil @foo : <T> (T) -> T

sil @example
bb0:
  %1 = function_ref @foo : <T> (T) -> T
  %2 = differentiable_function %1
  %3 = differentiable_function_extract [vjp] %2
  ...

Currently, is the symptom that one differentiability witness is chosen at random during differentiable_function canonicalization?

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You'd get an error that foo is not differentiable, even if the next instruction applies the vjp to something that conforms to A. However, I don't know if any swift code will actually generate SIL like that.

With this check here, I know of no swift code that causes any symptoms.

A symptom that you can get from real swift, if you remove the check here, is:

protocol P {
  @differentiable
  func f(_ x: Float) -> Float
}

extension P {
  @differentiable
  func f(_ x: Float) -> Float
}

struct S: P {}

=>

error: function is not differentiable because `Self: P` is not satisfied

(error from memory, don't have a compiler to test it on right now)

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The reason that error happens is that the differentiability witness table for P.f has a Self: P constraint, and the substitution map that gets passed in to diagnoseUnsatisfiedRequirements doesn't have anything satisfying those constraints.

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I see, thanks for the details! I wonder if this is a deficiency in the code around diagnoseUnsatisfiedRequirements (e.g. logic for computing the substitution map). I'll try to reproduce the issue after this patch lands.

if (origFnTy->getInvocationGenericSignature() && derivativeGenSig &&
origFnTy->getInvocationGenericSignature()->isEqual(derivativeGenSig))
return false;

// If there are no derivative requirements, return false.
if (!derivativeGenSig)
return false;
Expand Down Expand Up @@ -528,6 +538,7 @@ emitDerivativeFunctionReference(
peerThroughFunctionConversions<FunctionRefInst>(original)) {
auto loc = originalFRI->getLoc();
auto *originalFn = originalFRI->getReferencedFunctionOrNull();
assert(originalFn);
auto originalFnTy = originalFn->getLoweredFunctionType();
auto *desiredResultIndices =
IndexSubset::get(context.getASTContext(), originalFnTy->getNumResults(),
Expand Down Expand Up @@ -636,8 +647,9 @@ emitDerivativeFunctionReference(
substMap = ai->getSubstitutionMap();
}
if (diagnoseUnsatisfiedRequirements(
context, minimalWitness->getDerivativeGenericSignature(), substMap,
invoker, original.getLoc().getSourceLoc()))
context, original->getType().castTo<SILFunctionType>(),
minimalWitness->getDerivativeGenericSignature(), substMap, invoker,
original.getLoc().getSourceLoc()))
return None;
DifferentiabilityWitnessFunctionKind witnessKind;
switch (kind) {
Expand Down
8 changes: 5 additions & 3 deletions lib/Sema/DerivedConformanceDifferentiable.cpp
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Expand Up @@ -614,16 +614,18 @@ getOrSynthesizeTangentVectorStruct(DerivedConformance &derived, Identifier id) {
if (member->getAttrs().hasAttribute<DifferentiableAttr>() ||
getter->getAttrs().hasAttribute<DifferentiableAttr>())
continue;
GenericSignature derivativeGenSig = GenericSignature();
GenericSignature derivativeGenericSignature =
getter->getGenericSignature();
// If the parent declaration context is an extension, the nominal type may
// conditionally conform to `Differentiable`. Use the extension generic
// requirements in getter `@differentiable` attributes.
if (auto *extDecl = dyn_cast<ExtensionDecl>(parentDC->getAsDecl()))
derivativeGenSig = extDecl->getGenericSignature();
if (auto extGenSig = extDecl->getGenericSignature())
derivativeGenericSignature = extGenSig;
auto *diffableAttr = DifferentiableAttr::create(
getter, /*implicit*/ true, SourceLoc(), SourceLoc(),
/*linear*/ false, /*parameterIndices*/ IndexSubset::get(C, 1, {0}),
/*jvp*/ None, /*vjp*/ None, derivativeGenSig);
/*jvp*/ None, /*vjp*/ None, derivativeGenericSignature);
member->getAttrs().add(diffableAttr);
}
}
Expand Down
20 changes: 12 additions & 8 deletions lib/Sema/TypeCheckAttr.cpp
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Expand Up @@ -3429,13 +3429,16 @@ DifferentiableAttributeParameterIndicesRequest::evaluate(
// Start type-checking the arguments of the @differentiable attribute. This
// covers 'wrt:', 'jvp:', 'vjp:', and 'where', all of which are optional.

// Note: If there is a 'where' clause, then the generic signature from that
// overwrites this.
GenericSignature derivativeGenSig = original->getGenericSignature();

// Handle 'where' clause, if it exists.
// - Resolve attribute where clause requirements and store in the attribute
// for serialization.
// - Compute generic signature for autodiff derivative functions based on
// the original function's generate signature and the attribute's where
// clause requirements.
GenericSignature whereClauseGenSig = GenericSignature();
GenericEnvironment *whereClauseGenEnv = nullptr;
if (auto *whereClause = attr->getWhereClause()) {
// `@differentiable` attributes on protocol requirements do not support
Expand Down Expand Up @@ -3507,13 +3510,14 @@ DifferentiableAttributeParameterIndicesRequest::evaluate(

// Compute generic signature and environment for autodiff associated
// functions.
whereClauseGenSig = std::move(builder).computeGenericSignature(
derivativeGenSig = std::move(builder).computeGenericSignature(
attr->getLocation(), /*allowConcreteGenericParams=*/true);
whereClauseGenEnv = whereClauseGenSig->getGenericEnvironment();
// Store the resolved derivative generic signature in the attribute.
attr->setDerivativeGenericSignature(whereClauseGenSig);
whereClauseGenEnv = derivativeGenSig->getGenericEnvironment();
}

// Store the resolved derivative generic signature in the attribute.
attr->setDerivativeGenericSignature(derivativeGenSig);

// Validate the 'wrt:' parameters.

// Get the parsed wrt param indices, which have not yet been checked.
Expand Down Expand Up @@ -3572,7 +3576,7 @@ DifferentiableAttributeParameterIndicesRequest::evaluate(
originalFnTy->getAutoDiffDerivativeFunctionType(
checkedWrtParamIndices, /*resultIndex*/ 0,
AutoDiffDerivativeFunctionKind::JVP, lookupConformance,
whereClauseGenSig, /*makeSelfParamFirst*/ true);
derivativeGenSig, /*makeSelfParamFirst*/ true);

auto isValidJVP = [&](AbstractFunctionDecl *jvpCandidate) -> bool {
return checkFunctionSignature(
Expand All @@ -3596,7 +3600,7 @@ DifferentiableAttributeParameterIndicesRequest::evaluate(
originalFnTy->getAutoDiffDerivativeFunctionType(
checkedWrtParamIndices, /*resultIndex*/ 0,
AutoDiffDerivativeFunctionKind::VJP, lookupConformance,
whereClauseGenSig, /*makeSelfParamFirst*/ true);
derivativeGenSig, /*makeSelfParamFirst*/ true);

auto isValidVJP = [&](AbstractFunctionDecl *vjpCandidate) -> bool {
return checkFunctionSignature(
Expand Down Expand Up @@ -3652,7 +3656,7 @@ DifferentiableAttributeParameterIndicesRequest::evaluate(
// Register derivative function configuration.
auto *resultIndices = IndexSubset::get(ctx, 1, {0});
original->addDerivativeFunctionConfiguration(
{checkedWrtParamIndices, resultIndices, whereClauseGenSig});
{checkedWrtParamIndices, resultIndices, derivativeGenSig});
return checkedWrtParamIndices;
}

Expand Down
50 changes: 34 additions & 16 deletions lib/Sema/TypeCheckProtocol.cpp
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Expand Up @@ -556,37 +556,55 @@ swift::matchWitness(
(void)reqDiffAttr->getParameterIndices();
}
for (auto *reqDiffAttr : reqAttrs.getAttributes<DifferentiableAttr>()) {
bool foundExactAttr = false;
bool foundSupersetAttr = false;
bool foundExactConfig = false;
Optional<AutoDiffConfig> supersetConfig = None;
for (auto witnessConfig :
witnessAFD->getDerivativeFunctionConfigurations()) {
// We can't use witnesses that have generic signatures not satisfied by
// the requirement's generic signature.
if (witnessConfig.derivativeGenericSignature &&
!witnessConfig.derivativeGenericSignature
->requirementsNotSatisfiedBy(
reqDiffAttr->getDerivativeGenericSignature())
.empty())
continue;
// All the witness's derivative generic requirements must be satisfied
// by the requirement's derivative generic requirements OR by the
// conditional conformance requirements.
if (witnessConfig.derivativeGenericSignature) {
bool genericRequirementsSatisfied = true;
auto reqDiffGenSig = reqDiffAttr->getDerivativeGenericSignature();
auto conformanceGenSig = dc->getGenericSignatureOfContext();
for (const auto &req :
witnessConfig.derivativeGenericSignature->getRequirements()) {
auto substReq = req.subst(result.WitnessSubstitutions);
bool reqDiffGenSigSatisfies =
reqDiffGenSig && substReq &&
reqDiffGenSig->isRequirementSatisfied(*substReq);
bool conformanceGenSigSatisfies =
conformanceGenSig &&
conformanceGenSig->isRequirementSatisfied(req);
if (!reqDiffGenSigSatisfies && !conformanceGenSigSatisfies) {
genericRequirementsSatisfied = false;
break;
}
}
if (!genericRequirementsSatisfied)
continue;
}

if (witnessConfig.parameterIndices ==
reqDiffAttr->getParameterIndices())
foundExactAttr = true;
reqDiffAttr->getParameterIndices()) {
foundExactConfig = true;
break;
}
if (witnessConfig.parameterIndices->isSupersetOf(
reqDiffAttr->getParameterIndices()))
foundSupersetAttr = true;
supersetConfig = witnessConfig;
}
if (!foundExactAttr) {
if (!foundExactConfig) {
bool success = false;
if (foundSupersetAttr) {
if (supersetConfig) {
// If the witness has a "superset" derivative configuration, create an
// implicit `@differentiable` attribute with the exact requirement
// `@differentiable` attribute parameter indices.
auto *newAttr = DifferentiableAttr::create(
witnessAFD, /*implicit*/ true, reqDiffAttr->AtLoc,
reqDiffAttr->getRange(), reqDiffAttr->isLinear(),
reqDiffAttr->getParameterIndices(), /*jvp*/ None,
/*vjp*/ None, reqDiffAttr->getDerivativeGenericSignature());
/*vjp*/ None, supersetConfig->derivativeGenericSignature);
auto insertion = ctx.DifferentiableAttrs.try_emplace(
{witnessAFD, newAttr->getParameterIndices()}, newAttr);
// Valid `@differentiable` attributes are uniqued by original function
Expand Down
5 changes: 1 addition & 4 deletions test/AutoDiff/derivative_registration.swift
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Expand Up @@ -153,10 +153,7 @@ DerivativeRegistrationTests.testWithLeakChecking("DerivativeGenericSignature") {
let generic = Generic<Float>()
let x: Tracked<Float> = 3
let dx = gradient(at: x) { x in generic.instanceMethod(x) }
// NOTE(TF-1046): `gradient(at:in:)` calls the generated derivative for
// `Generic.instanceMethod` is used, not the registered derivative. This
// behavior is likely not expected by users; TF-1046 will fix this.
expectEqual(1, dx)
expectEqual(1000, dx)
}

runAllTests()
9 changes: 5 additions & 4 deletions test/AutoDiff/loadable_by_address_cross_module.swift
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Expand Up @@ -14,14 +14,15 @@
// Next, check that differentiability_witness_functions in the client get
// correctly modified by LBA.

// RUN: %target-swift-frontend -emit-sil -I%t %s
// RUN: %target-swift-frontend -emit-sil -I%t %s | %FileCheck %s -check-prefix=CHECK-CLIENT-PRE-LBA
// RUN: %target-swift-frontend -c -I%t %s -Xllvm -sil-print-after=loadable-address 2>&1 | %FileCheck %s -check-prefix=CHECK-CLIENT-POST-LBA

// CHECK-CLIENT-PRE-LBA: differentiability_witness_function [jvp] [parameters 0 1] [results 0] @${{.*}}LBAModifiedFunction{{.*}} : $@convention(method) <τ_0_0> (Float, LargeLoadableType<τ_0_0>) -> Float
// CHECK-CLIENT-PRE-LBA: differentiability_witness_function [vjp] [parameters 0 1] [results 0] @${{.*}}LBAModifiedFunction{{.*}} : $@convention(method) <τ_0_0> (Float, LargeLoadableType<τ_0_0>) -> Float
// CHECK-CLIENT-PRE-LBA: differentiability_witness_function [jvp] [parameters 0 1] [results 0] <T> @${{.*}}LBAModifiedFunction{{.*}} : $@convention(method) <τ_0_0> (Float, LargeLoadableType<τ_0_0>) -> Float
// CHECK-CLIENT-PRE-LBA: differentiability_witness_function [vjp] [parameters 0 1] [results 0] <T> @${{.*}}LBAModifiedFunction{{.*}} : $@convention(method) <τ_0_0> (Float, LargeLoadableType<τ_0_0>) -> Float

// CHECK-CLIENT-POST-LBA: differentiability_witness_function [jvp] [parameters 0 1] [results 0] @${{.*}}LBAModifiedFunction{{.*}} : $@convention(method) <τ_0_0> (Float, @in_constant LargeLoadableType<τ_0_0>) -> Float as $@convention(method) <τ_0_0> (Float, @in_constant LargeLoadableType<τ_0_0>) -> (Float, @owned @callee_guaranteed (Float, @in_constant LargeLoadableType<τ_0_0>) -> Float)
// CHECK-CLIENT-POST-LBA: differentiability_witness_function [vjp] [parameters 0 1] [results 0] @${{.*}}LBAModifiedFunction{{.*}} : $@convention(method) <τ_0_0> (Float, @in_constant LargeLoadableType<τ_0_0>) -> Float as $@convention(method) <τ_0_0> (Float, @in_constant LargeLoadableType<τ_0_0>) -> (Float, @owned @callee_guaranteed (Float) -> (Float, LargeLoadableType<τ_0_0>))
// CHECK-CLIENT-POST-LBA: differentiability_witness_function [jvp] [parameters 0 1] [results 0] <T> @${{.*}}LBAModifiedFunction{{.*}} : $@convention(method) <τ_0_0> (Float, @in_constant LargeLoadableType<τ_0_0>) -> Float as $@convention(method) <τ_0_0> (Float, @in_constant LargeLoadableType<τ_0_0>) -> (Float, @owned @callee_guaranteed (Float, @in_constant LargeLoadableType<τ_0_0>) -> Float)
// CHECK-CLIENT-POST-LBA: differentiability_witness_function [vjp] [parameters 0 1] [results 0] <T> @${{.*}}LBAModifiedFunction{{.*}} : $@convention(method) <τ_0_0> (Float, @in_constant LargeLoadableType<τ_0_0>) -> Float as $@convention(method) <τ_0_0> (Float, @in_constant LargeLoadableType<τ_0_0>) -> (Float, @owned @callee_guaranteed (Float) -> (Float, LargeLoadableType<τ_0_0>))

// Finally, execute the test.

Expand Down
4 changes: 2 additions & 2 deletions test/AutoDiff/nonvaried_result.swift
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Expand Up @@ -44,7 +44,7 @@ NonVariedResultTests.testWithLeakChecking("SingleBasicBlockGeneric") {
expectEqual((0, 0, 0), gradient(at: 3, 4, 5) { simpleGeneric($0, $1, $2) })
}

// CHECK-LABEL: sil private [ossa] @AD__${{.*}}simpleGeneric{{.*}}pullback_src_0_wrt_0_1_2 : $@convention(thin) <τ_0_0 where τ_0_0 : Differentiable, τ_0_0 == τ_0_0.TangentVector> (@in_guaranteed τ_0_0.TangentVector, @owned _AD__$s4nullyycfU0_13simpleGenericL_yxx_x23DifferentiationUnittest7TrackedVySfGts14DifferentiableRz13TangentVectorsAGPQzRszlF_bb0__PB__src_0_wrt_0_1_2<τ_0_0>) -> (@out τ_0_0.TangentVector, @out τ_0_0.TangentVector, @owned Tracked<Float>) {
// CHECK-LABEL: sil private [ossa] @AD__${{.*}}simpleGeneric{{.*}}pullback_src_0_wrt_0_1_2{{.*}} : $@convention(thin) <τ_0_0 where τ_0_0 : Differentiable, τ_0_0 == τ_0_0.TangentVector> (@in_guaranteed τ_0_0.TangentVector, @owned _AD__$s4nullyycfU0_13simpleGenericL_yxx_x23DifferentiationUnittest7TrackedVySfGts14DifferentiableRz13TangentVectorsAGPQzRszlF_bb0__PB__src_0_wrt_0_1_2<τ_0_0>) -> (@out τ_0_0.TangentVector, @out τ_0_0.TangentVector, @owned Tracked<Float>) {
// CHECK: bb0([[DX:%.*]] : $*τ_0_0, [[DY:%.*]] : $*τ_0_0, [[SEED:%.*]] : $*τ_0_0, [[PB_STRUCT:%.*]] : [[PB_STRUCT_TYPE:.*]]):
// CHECK: [[ZERO_FN_X:%.*]] = witness_method $τ_0_0, #AdditiveArithmetic.zero!getter.1 : <Self where Self : AdditiveArithmetic> (Self.Type) -> () -> Self : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@thick τ_0_0.Type) -> @out τ_0_0
// CHECK: [[METATYPE_X:%.*]] = metatype $@thick τ_0_0.Type
Expand Down Expand Up @@ -150,7 +150,7 @@ NonVariedResultTests.testWithLeakChecking("ComplexGeneric") {
expectEqual(0, pullback(at: Tracked<Float>(3)) { complexGeneric(10, $0) }(1))
}

// CHECK-LABEL: sil private [ossa] @AD__${{.*}}complexGeneric{{.*}}pullback_src_0_wrt_1 : $@convention(thin) <τ_0_0 where τ_0_0 : Differentiable> (@in_guaranteed τ_0_0.TangentVector, @owned _AD__$s4nullyycfU4_14complexGenericL_yxx_xts14DifferentiableRzlF_bb9__PB__src_0_wrt_1<τ_0_0>) -> @out τ_0_0.TangentVector {
// CHECK-LABEL: sil private [ossa] @AD__${{.*}}complexGeneric{{.*}}pullback_src_0_wrt_1{{.*}} : $@convention(thin) <τ_0_0 where τ_0_0 : Differentiable> (@in_guaranteed τ_0_0.TangentVector, @owned _AD__$s4nullyycfU4_14complexGenericL_yxx_xts14DifferentiableRzlF_bb9__PB__src_0_wrt_1<τ_0_0>) -> @out τ_0_0.TangentVector {
// CHECK: bb0([[DY:%.*]] : $*τ_0_0.TangentVector, [[SEED:%.*]] : $*τ_0_0.TangentVector, [[PB_STRUCT:%.*]] : @owned [[PB_STRUCT_TYPE:.*]]):
// CHECK: destroy_value [[PB_STRUCT]] : [[PB_STRUCT_TYPE]]
// CHECK: [[ZERO_FN:%.*]] = witness_method $τ_0_0.TangentVector, #AdditiveArithmetic.zero!getter.1 : <Self where Self : AdditiveArithmetic> (Self.Type) -> () -> Self : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@thick τ_0_0.Type) -> @out τ_0_0
Expand Down
2 changes: 1 addition & 1 deletion test/AutoDiff/protocol_requirement_autodiff_diags.swift
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Expand Up @@ -13,6 +13,6 @@ struct AttemptsToSatisfyRequirement: HasRequirement {
// This does not satisfy the requirement because the differentiable attribute is more
// constrained than the requirement's differentiable attribute.
@differentiable(where T: P)
// expected-note @+1 {{candidate is missing attribute '@differentiable'}}
// expected-note @+1 {{candidate is missing attribute '@differentiable(wrt: (x, y))'}}
func requirement<T: Differentiable>(_ x: T, _ y: T) -> T { x }
}
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