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[clang][ExtractAPI] improve template argument name deduction #77716

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Merged
merged 1 commit into from
Apr 2, 2024
Merged

[clang][ExtractAPI] improve template argument name deduction #77716

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19 changes: 4 additions & 15 deletions clang/include/clang/ExtractAPI/DeclarationFragments.h
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Original file line number Diff line number Diff line change
Expand Up @@ -27,8 +27,6 @@
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/Specifiers.h"
#include "clang/Lex/MacroInfo.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include <vector>

namespace clang {
Expand Down Expand Up @@ -315,13 +313,9 @@ class DeclarationFragmentsBuilder {
static DeclarationFragments
getFragmentsForTemplateParameters(ArrayRef<NamedDecl *>);

static std::string
getNameForTemplateArgument(const ArrayRef<NamedDecl *>, std::string);

static DeclarationFragments
getFragmentsForTemplateArguments(const ArrayRef<TemplateArgument>,
ASTContext &,
const std::optional<ArrayRef<NamedDecl *>>);
static DeclarationFragments getFragmentsForTemplateArguments(
const ArrayRef<TemplateArgument>, ASTContext &,
const std::optional<ArrayRef<TemplateArgumentLoc>>);

static DeclarationFragments getFragmentsForConcept(const ConceptDecl *);

Expand Down Expand Up @@ -430,12 +424,7 @@ DeclarationFragmentsBuilder::getFunctionSignature(const FunctionT *Function) {
if (isa<FunctionDecl>(Function) &&
dyn_cast<FunctionDecl>(Function)->getDescribedFunctionTemplate() &&
StringRef(ReturnType.begin()->Spelling).starts_with("type-parameter")) {
std::string ProperArgName =
getNameForTemplateArgument(dyn_cast<FunctionDecl>(Function)
->getDescribedFunctionTemplate()
->getTemplateParameters()
->asArray(),
ReturnType.begin()->Spelling);
std::string ProperArgName = Function->getReturnType().getAsString();
ReturnType.begin()->Spelling.swap(ProperArgName);
}
ReturnType.append(std::move(After));
Expand Down
51 changes: 10 additions & 41 deletions clang/lib/ExtractAPI/DeclarationFragments.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -14,14 +14,11 @@
#include "clang/ExtractAPI/DeclarationFragments.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/QualTypeNames.h"
#include "clang/AST/Type.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/OperatorKinds.h"
#include "clang/ExtractAPI/TypedefUnderlyingTypeResolver.h"
#include "clang/Index/USRGeneration.h"
#include "llvm/ADT/StringSwitch.h"
#include <typeinfo>

using namespace clang::extractapi;
using namespace llvm;
Expand Down Expand Up @@ -535,9 +532,7 @@ DeclarationFragmentsBuilder::getFragmentsForVarTemplate(const VarDecl *Var) {
getFragmentsForType(T, Var->getASTContext(), After);
if (StringRef(ArgumentFragment.begin()->Spelling)
.starts_with("type-parameter")) {
std::string ProperArgName = getNameForTemplateArgument(
Var->getDescribedVarTemplate()->getTemplateParameters()->asArray(),
ArgumentFragment.begin()->Spelling);
std::string ProperArgName = T.getAsString();
ArgumentFragment.begin()->Spelling.swap(ProperArgName);
}
Fragments.append(std::move(ArgumentFragment))
Expand Down Expand Up @@ -570,12 +565,7 @@ DeclarationFragmentsBuilder::getFragmentsForParam(const ParmVarDecl *Param) {

if (StringRef(TypeFragments.begin()->Spelling)
.starts_with("type-parameter")) {
std::string ProperArgName = getNameForTemplateArgument(
dyn_cast<FunctionDecl>(Param->getDeclContext())
->getDescribedFunctionTemplate()
->getTemplateParameters()
->asArray(),
TypeFragments.begin()->Spelling);
std::string ProperArgName = Param->getOriginalType().getAsString();
TypeFragments.begin()->Spelling.swap(ProperArgName);
}

Expand Down Expand Up @@ -668,11 +658,7 @@ DeclarationFragmentsBuilder::getFragmentsForFunction(const FunctionDecl *Func) {
getFragmentsForType(Func->getReturnType(), Func->getASTContext(), After);
if (StringRef(ReturnValueFragment.begin()->Spelling)
.starts_with("type-parameter")) {
std::string ProperArgName =
getNameForTemplateArgument(Func->getDescribedFunctionTemplate()
->getTemplateParameters()
->asArray(),
ReturnValueFragment.begin()->Spelling);
std::string ProperArgName = Func->getReturnType().getAsString();
ReturnValueFragment.begin()->Spelling.swap(ProperArgName);
}

Expand Down Expand Up @@ -961,25 +947,6 @@ DeclarationFragmentsBuilder::getFragmentsForTemplateParameters(
return Fragments;
}

// Find the name of a template argument from the template's parameters.
std::string DeclarationFragmentsBuilder::getNameForTemplateArgument(
const ArrayRef<NamedDecl *> TemplateParameters, std::string TypeParameter) {
// The arg is a generic parameter from a partial spec, e.g.
// T in template<typename T> Foo<T, int>.
//
// Those names appear as "type-parameter-<index>-<depth>", so we must find its
// name from the template's parameter list.
for (unsigned i = 0; i < TemplateParameters.size(); ++i) {
const auto *Parameter =
dyn_cast<TemplateTypeParmDecl>(TemplateParameters[i]);
if (TypeParameter.compare("type-parameter-" +
std::to_string(Parameter->getDepth()) + "-" +
std::to_string(Parameter->getIndex())) == 0)
return std::string(TemplateParameters[i]->getName());
}
llvm_unreachable("Could not find the name of a template argument.");
}

// Get fragments for template arguments, e.g. int in template<typename T>
// Foo<int>;
//
Expand All @@ -989,7 +956,7 @@ std::string DeclarationFragmentsBuilder::getNameForTemplateArgument(
DeclarationFragments
DeclarationFragmentsBuilder::getFragmentsForTemplateArguments(
const ArrayRef<TemplateArgument> TemplateArguments, ASTContext &Context,
const std::optional<ArrayRef<NamedDecl *>> TemplateParameters) {
const std::optional<ArrayRef<TemplateArgumentLoc>> TemplateArgumentLocs) {
DeclarationFragments Fragments;
for (unsigned i = 0, end = TemplateArguments.size(); i != end; ++i) {
if (i)
Expand All @@ -1003,8 +970,10 @@ DeclarationFragmentsBuilder::getFragmentsForTemplateArguments(

if (StringRef(ArgumentFragment.begin()->Spelling)
.starts_with("type-parameter")) {
std::string ProperArgName = getNameForTemplateArgument(
TemplateParameters.value(), ArgumentFragment.begin()->Spelling);
std::string ProperArgName = TemplateArgumentLocs.value()[i]
.getTypeSourceInfo()
->getType()
.getAsString();
ArgumentFragment.begin()->Spelling.swap(ProperArgName);
}
Fragments.append(std::move(ArgumentFragment));
Expand Down Expand Up @@ -1089,7 +1058,7 @@ DeclarationFragmentsBuilder::getFragmentsForClassTemplatePartialSpecialization(
.append("<", DeclarationFragments::FragmentKind::Text)
.append(getFragmentsForTemplateArguments(
Decl->getTemplateArgs().asArray(), Decl->getASTContext(),
Decl->getTemplateParameters()->asArray()))
Decl->getTemplateArgsAsWritten()->arguments()))
.append(">", DeclarationFragments::FragmentKind::Text)
.append(";", DeclarationFragments::FragmentKind::Text);
}
Expand Down Expand Up @@ -1130,7 +1099,7 @@ DeclarationFragmentsBuilder::getFragmentsForVarTemplatePartialSpecialization(
.append("<", DeclarationFragments::FragmentKind::Text)
.append(getFragmentsForTemplateArguments(
Decl->getTemplateArgs().asArray(), Decl->getASTContext(),
Decl->getTemplateParameters()->asArray()))
Decl->getTemplateArgsAsWritten()->arguments()))
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Looks like the right thing to me!

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In this patch getFragmentsForTemplateArguments, which is being called here, is changed to accept ArrayRef<TemplateArgumentLoc> (which is what the changed line returns) instead of ArrayRef<NamedDecl *> because of the nasty loop that was deleted in DeclarationFragments.cpp:962. A TemplateArgumentLoc gives us the name of the specialization's type argument directly, instead of comparing with the declaration's template parameters.

.append(">", DeclarationFragments::FragmentKind::Text)
.append(";", DeclarationFragments::FragmentKind::Text);
}
Expand Down