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[Clang][CTAD][NFC] Unify transformTemplateParameter() #100865

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Merged
merged 3 commits into from
Jul 28, 2024
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[Clang][CTAD][NFC] Unify transformTemplateParameter() #100865

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13724c6
[Clang][CTAD][NFC] Unify transformTemplateParameter()
zyn0217 Jul 27, 2024
64da16d
getNumLevels() -> getNumSubstitutedLevels()
zyn0217 Jul 27, 2024
0016929
Drop getTemplateParameter{Index,Depth}()
zyn0217 Jul 28, 2024
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119 changes: 42 additions & 77 deletions clang/lib/Sema/SemaTemplateDeductionGuide.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,7 @@
#include "clang/Sema/Overload.h"
#include "clang/Sema/Ownership.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Template.h"
#include "clang/Sema/TemplateDeduction.h"
#include "llvm/ADT/ArrayRef.h"
Expand Down Expand Up @@ -241,11 +242,10 @@ NamedDecl *buildDeductionGuide(
}

// Transform a given template type parameter `TTP`.
TemplateTypeParmDecl *
transformTemplateTypeParam(Sema &SemaRef, DeclContext *DC,
TemplateTypeParmDecl *TTP,
MultiLevelTemplateArgumentList &Args,
unsigned NewDepth, unsigned NewIndex) {
TemplateTypeParmDecl *transformTemplateTypeParam(
Sema &SemaRef, DeclContext *DC, TemplateTypeParmDecl *TTP,
MultiLevelTemplateArgumentList &Args, unsigned NewDepth, unsigned NewIndex,
bool EvaluateConstraint) {
// TemplateTypeParmDecl's index cannot be changed after creation, so
// substitute it directly.
auto *NewTTP = TemplateTypeParmDecl::Create(
Expand All @@ -257,7 +257,7 @@ transformTemplateTypeParam(Sema &SemaRef, DeclContext *DC,
: std::nullopt);
if (const auto *TC = TTP->getTypeConstraint())
SemaRef.SubstTypeConstraint(NewTTP, TC, Args,
/*EvaluateConstraint=*/true);
/*EvaluateConstraint=*/EvaluateConstraint);
if (TTP->hasDefaultArgument()) {
TemplateArgumentLoc InstantiatedDefaultArg;
if (!SemaRef.SubstTemplateArgument(
Expand All @@ -284,6 +284,22 @@ transformTemplateParam(Sema &SemaRef, DeclContext *DC,
return NewParam;
}

NamedDecl *transformTemplateParameter(Sema &SemaRef, DeclContext *DC,
NamedDecl *TemplateParam,
MultiLevelTemplateArgumentList &Args,
unsigned NewIndex, unsigned NewDepth,
bool EvaluateConstraint = true) {
if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam))
return transformTemplateTypeParam(
SemaRef, DC, TTP, Args, NewDepth, NewIndex,
/*EvaluateConstraint=*/EvaluateConstraint);
if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
return transformTemplateParam(SemaRef, DC, TTP, Args, NewIndex, NewDepth);
if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(TemplateParam))
return transformTemplateParam(SemaRef, DC, NTTP, Args, NewIndex, NewDepth);
llvm_unreachable("Unhandled template parameter types");
}

/// Transform to convert portions of a constructor declaration into the
/// corresponding deduction guide, per C++1z [over.match.class.deduct]p1.
struct ConvertConstructorToDeductionGuideTransform {
Expand Down Expand Up @@ -358,20 +374,21 @@ struct ConvertConstructorToDeductionGuideTransform {
Args.addOuterRetainedLevel();
if (NestedPattern)
Args.addOuterRetainedLevels(NestedPattern->getTemplateDepth());
NamedDecl *NewParam = transformTemplateParameter(Param, Args);
auto [Depth, Index] = getDepthAndIndex(Param);
NamedDecl *NewParam = transformTemplateParameter(
SemaRef, DC, Param, Args, Index + Depth1IndexAdjustment, Depth - 1);
if (!NewParam)
return nullptr;
// Constraints require that we substitute depth-1 arguments
// to match depths when substituted for evaluation later
Depth1Args.push_back(SemaRef.Context.getInjectedTemplateArg(NewParam));

if (NestedPattern) {
TemplateDeclInstantiator Instantiator(SemaRef, DC,
OuterInstantiationArgs);
Instantiator.setEvaluateConstraints(false);
SemaRef.runWithSufficientStackSpace(NewParam->getLocation(), [&] {
NewParam = cast<NamedDecl>(Instantiator.Visit(NewParam));
});
auto [Depth, Index] = getDepthAndIndex(NewParam);
NewParam = transformTemplateParameter(
SemaRef, DC, NewParam, OuterInstantiationArgs, Index,
Depth - OuterInstantiationArgs.getNumSubstitutedLevels(),
/*EvaluateConstraint=*/false);
}

assert(NewParam->getTemplateDepth() == 0 &&
Expand Down Expand Up @@ -479,25 +496,6 @@ struct ConvertConstructorToDeductionGuideTransform {
}

private:
/// Transform a constructor template parameter into a deduction guide template
/// parameter, rebuilding any internal references to earlier parameters and
/// renumbering as we go.
NamedDecl *transformTemplateParameter(NamedDecl *TemplateParam,
MultiLevelTemplateArgumentList &Args) {
if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam))
return transformTemplateTypeParam(
SemaRef, DC, TTP, Args, TTP->getDepth() - 1,
Depth1IndexAdjustment + TTP->getIndex());
if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
return transformTemplateParam(SemaRef, DC, TTP, Args,
Depth1IndexAdjustment + TTP->getIndex(),
TTP->getDepth() - 1);
auto *NTTP = cast<NonTypeTemplateParmDecl>(TemplateParam);
return transformTemplateParam(SemaRef, DC, NTTP, Args,
Depth1IndexAdjustment + NTTP->getIndex(),
NTTP->getDepth() - 1);
}

QualType transformFunctionProtoType(
TypeLocBuilder &TLB, FunctionProtoTypeLoc TL,
SmallVectorImpl<ParmVarDecl *> &Params,
Expand Down Expand Up @@ -634,26 +632,6 @@ struct ConvertConstructorToDeductionGuideTransform {
}
};

unsigned getTemplateParameterDepth(NamedDecl *TemplateParam) {
if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam))
return TTP->getDepth();
if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
return TTP->getDepth();
if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(TemplateParam))
return NTTP->getDepth();
llvm_unreachable("Unhandled template parameter types");
}

unsigned getTemplateParameterIndex(NamedDecl *TemplateParam) {
if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam))
return TTP->getIndex();
if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
return TTP->getIndex();
if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(TemplateParam))
return NTTP->getIndex();
llvm_unreachable("Unhandled template parameter types");
}

// Find all template parameters that appear in the given DeducedArgs.
// Return the indices of the template parameters in the TemplateParams.
SmallVector<unsigned> TemplateParamsReferencedInTemplateArgumentList(
Expand Down Expand Up @@ -689,8 +667,10 @@ SmallVector<unsigned> TemplateParamsReferencedInTemplateArgumentList(

void MarkAppeared(NamedDecl *ND) {
if (llvm::isa<NonTypeTemplateParmDecl, TemplateTypeParmDecl,
TemplateTemplateParmDecl>(ND))
Mark(getTemplateParameterDepth(ND), getTemplateParameterIndex(ND));
TemplateTemplateParmDecl>(ND)) {
auto [Depth, Index] = getDepthAndIndex(ND);
Mark(Depth, Index);
}
}
void Mark(unsigned Depth, unsigned Index) {
if (Index < TemplateParamList->size() &&
Expand Down Expand Up @@ -722,20 +702,6 @@ bool hasDeclaredDeductionGuides(DeclarationName Name, DeclContext *DC) {
return false;
}

NamedDecl *transformTemplateParameter(Sema &SemaRef, DeclContext *DC,
NamedDecl *TemplateParam,
MultiLevelTemplateArgumentList &Args,
unsigned NewIndex, unsigned NewDepth) {
if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam))
return transformTemplateTypeParam(SemaRef, DC, TTP, Args, NewDepth,
NewIndex);
if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
return transformTemplateParam(SemaRef, DC, TTP, Args, NewIndex, NewDepth);
if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(TemplateParam))
return transformTemplateParam(SemaRef, DC, NTTP, Args, NewIndex, NewDepth);
llvm_unreachable("Unhandled template parameter types");
}

// Build the associated constraints for the alias deduction guides.
// C++ [over.match.class.deduct]p3.3:
// The associated constraints ([temp.constr.decl]) are the conjunction of the
Expand Down Expand Up @@ -791,7 +757,7 @@ buildAssociatedConstraints(Sema &SemaRef, FunctionTemplateDecl *F,
NamedDecl *NewParam = transformTemplateParameter(
SemaRef, AliasTemplate->getDeclContext(), TP, Args,
/*NewIndex=*/AdjustedAliasTemplateArgs.size(),
getTemplateParameterDepth(TP) + AdjustDepth);
getDepthAndIndex(TP).first + AdjustDepth);

TemplateArgument NewTemplateArgument =
Context.getInjectedTemplateArg(NewParam);
Expand All @@ -814,10 +780,10 @@ buildAssociatedConstraints(Sema &SemaRef, FunctionTemplateDecl *F,
Args.setKind(TemplateSubstitutionKind::Rewrite);
Args.addOuterTemplateArguments(TemplateArgsForBuildingRC);
// Rebuild the template parameter with updated depth and index.
NamedDecl *NewParam = transformTemplateParameter(
SemaRef, F->getDeclContext(), TP, Args,
/*NewIndex=*/FirstUndeducedParamIdx,
getTemplateParameterDepth(TP) + AdjustDepth);
NamedDecl *NewParam =
transformTemplateParameter(SemaRef, F->getDeclContext(), TP, Args,
/*NewIndex=*/FirstUndeducedParamIdx,
getDepthAndIndex(TP).first + AdjustDepth);
FirstUndeducedParamIdx += 1;
assert(TemplateArgsForBuildingRC[Index].isNull());
TemplateArgsForBuildingRC[Index] =
Expand Down Expand Up @@ -919,7 +885,7 @@ Expr *buildIsDeducibleConstraint(Sema &SemaRef,
NamedDecl *NewParam = transformTemplateParameter(
SemaRef, AliasTemplate->getDeclContext(), TP, Args,
/*NewIndex=*/TransformedTemplateArgs.size(),
getTemplateParameterDepth(TP) + AdjustDepth);
getDepthAndIndex(TP).first + AdjustDepth);

TemplateArgument NewTemplateArgument =
Context.getInjectedTemplateArg(NewParam);
Expand Down Expand Up @@ -1081,8 +1047,7 @@ BuildDeductionGuideForTypeAlias(Sema &SemaRef,
Args.addOuterTemplateArguments(TransformedDeducedAliasArgs);
NamedDecl *NewParam = transformTemplateParameter(
SemaRef, AliasTemplate->getDeclContext(), TP, Args,
/*NewIndex=*/FPrimeTemplateParams.size(),
getTemplateParameterDepth(TP));
/*NewIndex=*/FPrimeTemplateParams.size(), getDepthAndIndex(TP).first);
FPrimeTemplateParams.push_back(NewParam);

TemplateArgument NewTemplateArgument =
Expand All @@ -1101,7 +1066,7 @@ BuildDeductionGuideForTypeAlias(Sema &SemaRef,
Args.addOuterTemplateArguments(TemplateArgsForBuildingFPrime);
NamedDecl *NewParam = transformTemplateParameter(
SemaRef, F->getDeclContext(), TP, Args, FPrimeTemplateParams.size(),
getTemplateParameterDepth(TP));
getDepthAndIndex(TP).first);
FPrimeTemplateParams.push_back(NewParam);

assert(TemplateArgsForBuildingFPrime[FTemplateParamIdx].isNull() &&
Expand Down
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