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llvm-project/clang-tools-extra/clangd/CodeComplete.cpp

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//===--- CodeComplete.cpp ---------------------------------------*- C++-*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===---------------------------------------------------------------------===//
//
// AST-based completions are provided using the completion hooks in Sema.
//
// Signature help works in a similar way as code completion, but it is simpler
// as there are typically fewer candidates.
//
//===---------------------------------------------------------------------===//
#include "CodeComplete.h"
#include "CodeCompletionStrings.h"
#include "Compiler.h"
#include "FuzzyMatch.h"
#include "Logger.h"
#include "index/Index.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/FrontendActions.h"
#include "clang/Index/USRGeneration.h"
#include "clang/Sema/CodeCompleteConsumer.h"
#include "clang/Sema/Sema.h"
#include "llvm/Support/Format.h"
#include <queue>
namespace clang {
namespace clangd {
namespace {
CompletionItemKind toCompletionItemKind(CXCursorKind CursorKind) {
switch (CursorKind) {
case CXCursor_MacroInstantiation:
case CXCursor_MacroDefinition:
return CompletionItemKind::Text;
case CXCursor_CXXMethod:
case CXCursor_Destructor:
return CompletionItemKind::Method;
case CXCursor_FunctionDecl:
case CXCursor_FunctionTemplate:
return CompletionItemKind::Function;
case CXCursor_Constructor:
return CompletionItemKind::Constructor;
case CXCursor_FieldDecl:
return CompletionItemKind::Field;
case CXCursor_VarDecl:
case CXCursor_ParmDecl:
return CompletionItemKind::Variable;
// FIXME(ioeric): use LSP struct instead of class when it is suppoted in the
// protocol.
case CXCursor_StructDecl:
case CXCursor_ClassDecl:
case CXCursor_UnionDecl:
case CXCursor_ClassTemplate:
case CXCursor_ClassTemplatePartialSpecialization:
return CompletionItemKind::Class;
case CXCursor_Namespace:
case CXCursor_NamespaceAlias:
case CXCursor_NamespaceRef:
return CompletionItemKind::Module;
case CXCursor_EnumConstantDecl:
return CompletionItemKind::Value;
case CXCursor_EnumDecl:
return CompletionItemKind::Enum;
// FIXME(ioeric): figure out whether reference is the right type for aliases.
case CXCursor_TypeAliasDecl:
case CXCursor_TypeAliasTemplateDecl:
case CXCursor_TypedefDecl:
case CXCursor_MemberRef:
case CXCursor_TypeRef:
return CompletionItemKind::Reference;
default:
return CompletionItemKind::Missing;
}
}
CompletionItemKind
toCompletionItemKind(CodeCompletionResult::ResultKind ResKind,
CXCursorKind CursorKind) {
switch (ResKind) {
case CodeCompletionResult::RK_Declaration:
return toCompletionItemKind(CursorKind);
case CodeCompletionResult::RK_Keyword:
return CompletionItemKind::Keyword;
case CodeCompletionResult::RK_Macro:
return CompletionItemKind::Text; // unfortunately, there's no 'Macro'
// completion items in LSP.
case CodeCompletionResult::RK_Pattern:
return CompletionItemKind::Snippet;
}
llvm_unreachable("Unhandled CodeCompletionResult::ResultKind.");
}
CompletionItemKind toCompletionItemKind(index::SymbolKind Kind) {
using SK = index::SymbolKind;
switch (Kind) {
case SK::Unknown:
return CompletionItemKind::Missing;
case SK::Module:
case SK::Namespace:
case SK::NamespaceAlias:
return CompletionItemKind::Module;
case SK::Macro:
return CompletionItemKind::Text;
case SK::Enum:
return CompletionItemKind::Enum;
// FIXME(ioeric): use LSP struct instead of class when it is suppoted in the
// protocol.
case SK::Struct:
case SK::Class:
case SK::Protocol:
case SK::Extension:
case SK::Union:
return CompletionItemKind::Class;
// FIXME(ioeric): figure out whether reference is the right type for aliases.
case SK::TypeAlias:
case SK::Using:
return CompletionItemKind::Reference;
case SK::Function:
// FIXME(ioeric): this should probably be an operator. This should be fixed
// when `Operator` is support type in the protocol.
case SK::ConversionFunction:
return CompletionItemKind::Function;
case SK::Variable:
case SK::Parameter:
return CompletionItemKind::Variable;
case SK::Field:
return CompletionItemKind::Field;
// FIXME(ioeric): use LSP enum constant when it is supported in the protocol.
case SK::EnumConstant:
return CompletionItemKind::Value;
case SK::InstanceMethod:
case SK::ClassMethod:
case SK::StaticMethod:
case SK::Destructor:
return CompletionItemKind::Method;
case SK::InstanceProperty:
case SK::ClassProperty:
case SK::StaticProperty:
return CompletionItemKind::Property;
case SK::Constructor:
return CompletionItemKind::Constructor;
}
llvm_unreachable("Unhandled clang::index::SymbolKind.");
}
/// Get the optional chunk as a string. This function is possibly recursive.
///
/// The parameter info for each parameter is appended to the Parameters.
std::string
getOptionalParameters(const CodeCompletionString &CCS,
std::vector<ParameterInformation> &Parameters) {
std::string Result;
for (const auto &Chunk : CCS) {
switch (Chunk.Kind) {
case CodeCompletionString::CK_Optional:
assert(Chunk.Optional &&
"Expected the optional code completion string to be non-null.");
Result += getOptionalParameters(*Chunk.Optional, Parameters);
break;
case CodeCompletionString::CK_VerticalSpace:
break;
case CodeCompletionString::CK_Placeholder:
// A string that acts as a placeholder for, e.g., a function call
// argument.
// Intentional fallthrough here.
case CodeCompletionString::CK_CurrentParameter: {
// A piece of text that describes the parameter that corresponds to
// the code-completion location within a function call, message send,
// macro invocation, etc.
Result += Chunk.Text;
ParameterInformation Info;
Info.label = Chunk.Text;
Parameters.push_back(std::move(Info));
break;
}
default:
Result += Chunk.Text;
break;
}
}
return Result;
}
// Produces an integer that sorts in the same order as F.
// That is: a < b <==> encodeFloat(a) < encodeFloat(b).
uint32_t encodeFloat(float F) {
static_assert(std::numeric_limits<float>::is_iec559, "");
static_assert(sizeof(float) == sizeof(uint32_t), "");
constexpr uint32_t TopBit = ~(~uint32_t{0} >> 1);
// Get the bits of the float. Endianness is the same as for integers.
uint32_t U;
memcpy(&U, &F, sizeof(float));
// IEEE 754 floats compare like sign-magnitude integers.
if (U & TopBit) // Negative float.
return 0 - U; // Map onto the low half of integers, order reversed.
return U + TopBit; // Positive floats map onto the high half of integers.
}
// Returns a string that sorts in the same order as (-Score, Name), for LSP.
std::string sortText(float Score, llvm::StringRef Name) {
// We convert -Score to an integer, and hex-encode for readability.
// Example: [0.5, "foo"] -> "41000000foo"
std::string S;
llvm::raw_string_ostream OS(S);
write_hex(OS, encodeFloat(-Score), llvm::HexPrintStyle::Lower,
/*Width=*/2 * sizeof(Score));
OS << Name;
OS.flush();
return S;
}
/// A code completion result, in clang-native form.
/// It may be promoted to a CompletionItem if it's among the top-ranked results.
struct CompletionCandidate {
llvm::StringRef Name; // Used for filtering and sorting.
// We may have a result from Sema, from the index, or both.
const CodeCompletionResult *SemaResult = nullptr;
const Symbol *IndexResult = nullptr;
// Computes the "symbol quality" score for this completion. Higher is better.
float score() const {
// For now we just use the Sema priority, mapping it onto a 0-1 interval.
if (!SemaResult) // FIXME(sammccall): better scoring for index results.
return 0.3f; // fixed mediocre score for index-only results.
// Priority 80 is a really bad score.
float Score = 1 - std::min<float>(80, SemaResult->Priority) / 80;
switch (static_cast<CXAvailabilityKind>(SemaResult->Availability)) {
case CXAvailability_Available:
// No penalty.
break;
case CXAvailability_Deprecated:
Score *= 0.1f;
break;
case CXAvailability_NotAccessible:
case CXAvailability_NotAvailable:
Score = 0;
break;
}
return Score;
}
// Builds an LSP completion item.
CompletionItem build(const CompletionItemScores &Scores,
const CodeCompleteOptions &Opts,
CodeCompletionString *SemaCCS) const {
assert(bool(SemaResult) == bool(SemaCCS));
CompletionItem I;
if (SemaResult) {
I.kind = toCompletionItemKind(SemaResult->Kind, SemaResult->CursorKind);
getLabelAndInsertText(*SemaCCS, &I.label, &I.insertText,
Opts.EnableSnippets);
I.filterText = getFilterText(*SemaCCS);
I.documentation = getDocumentation(*SemaCCS);
I.detail = getDetail(*SemaCCS);
}
if (IndexResult) {
if (I.kind == CompletionItemKind::Missing)
I.kind = toCompletionItemKind(IndexResult->SymInfo.Kind);
// FIXME: reintroduce a way to show the index source for debugging.
if (I.label.empty())
I.label = IndexResult->CompletionLabel;
if (I.filterText.empty())
I.filterText = IndexResult->Name;
// FIXME(ioeric): support inserting/replacing scope qualifiers.
if (I.insertText.empty())
I.insertText = Opts.EnableSnippets
? IndexResult->CompletionSnippetInsertText
: IndexResult->CompletionPlainInsertText;
if (auto *D = IndexResult->Detail) {
if (I.documentation.empty())
I.documentation = D->Documentation;
if (I.detail.empty())
I.detail = D->CompletionDetail;
}
}
I.scoreInfo = Scores;
I.sortText = sortText(Scores.finalScore, Name);
I.insertTextFormat = Opts.EnableSnippets ? InsertTextFormat::Snippet
: InsertTextFormat::PlainText;
return I;
}
};
// Determine the symbol ID for a Sema code completion result, if possible.
llvm::Optional<SymbolID> getSymbolID(const CodeCompletionResult &R) {
switch (R.Kind) {
case CodeCompletionResult::RK_Declaration:
case CodeCompletionResult::RK_Pattern: {
llvm::SmallString<128> USR;
if (/*Ignore=*/clang::index::generateUSRForDecl(R.Declaration, USR))
return None;
return SymbolID(USR);
}
case CodeCompletionResult::RK_Macro:
// FIXME: Macros do have USRs, but the CCR doesn't contain enough info.
case CodeCompletionResult::RK_Keyword:
return None;
}
llvm_unreachable("unknown CodeCompletionResult kind");
}
// Scopes of the paritial identifier we're trying to complete.
// It is used when we query the index for more completion results.
struct SpecifiedScope {
// The scopes we should look in, determined by Sema.
//
// If the qualifier was fully resolved, we look for completions in these
// scopes; if there is an unresolved part of the qualifier, it should be
// resolved within these scopes.
//
// Examples of qualified completion:
//
// "::vec" => {""}
// "using namespace std; ::vec^" => {"", "std::"}
// "namespace ns {using namespace std;} ns::^" => {"ns::", "std::"}
// "std::vec^" => {""} // "std" unresolved
//
// Examples of unqualified completion:
//
// "vec^" => {""}
// "using namespace std; vec^" => {"", "std::"}
// "using namespace std; namespace ns { vec^ }" => {"ns::", "std::", ""}
//
// "" for global namespace, "ns::" for normal namespace.
std::vector<std::string> AccessibleScopes;
// The full scope qualifier as typed by the user (without the leading "::").
// Set if the qualifier is not fully resolved by Sema.
llvm::Optional<std::string> UnresolvedQualifier;
// Construct scopes being queried in indexes.
// This method format the scopes to match the index request representation.
std::vector<std::string> scopesForIndexQuery() {
std::vector<std::string> Results;
for (llvm::StringRef AS : AccessibleScopes) {
Results.push_back(AS);
if (UnresolvedQualifier)
Results.back() += *UnresolvedQualifier;
}
return Results;
}
};
// Get all scopes that will be queried in indexes.
std::vector<std::string> getQueryScopes(CodeCompletionContext &CCContext,
const SourceManager& SM) {
auto GetAllAccessibleScopes = [](CodeCompletionContext& CCContext) {
SpecifiedScope Info;
for (auto* Context : CCContext.getVisitedContexts()) {
if (isa<TranslationUnitDecl>(Context))
Info.AccessibleScopes.push_back(""); // global namespace
else if (const auto*NS = dyn_cast<NamespaceDecl>(Context))
Info.AccessibleScopes.push_back(NS->getQualifiedNameAsString() + "::");
}
return Info;
};
auto SS = CCContext.getCXXScopeSpecifier();
// Unqualified completion (e.g. "vec^").
if (!SS) {
// FIXME: Once we can insert namespace qualifiers and use the in-scope
// namespaces for scoring, search in all namespaces.
// FIXME: Capture scopes and use for scoring, for example,
// "using namespace std; namespace foo {v^}" =>
// foo::value > std::vector > boost::variant
return GetAllAccessibleScopes(CCContext).scopesForIndexQuery();
}
// Qualified completion ("std::vec^"), we have two cases depending on whether
// the qualifier can be resolved by Sema.
if ((*SS)->isValid()) { // Resolved qualifier.
// FIXME: Disable Sema typo correction during code completion.
// The resolved qualifier might not perfectly match the written qualifier.
// e.g. "namespace clang { clangd::^ }", we will get "clang" declaration
// for completion "clangd::".
return GetAllAccessibleScopes(CCContext).scopesForIndexQuery();
}
// Unresolved qualifier.
// FIXME: When Sema can resolve part of a scope chain (e.g.
// "known::unknown::id"), we should expand the known part ("known::") rather
// than treating the whole thing as unknown.
SpecifiedScope Info;
Info.AccessibleScopes.push_back(""); // global namespace
Info.UnresolvedQualifier =
Lexer::getSourceText(CharSourceRange::getCharRange((*SS)->getRange()),
SM, clang::LangOptions()).ltrim("::");
// Sema excludes the trailing "::".
if (!Info.UnresolvedQualifier->empty())
*Info.UnresolvedQualifier += "::";
return Info.scopesForIndexQuery();
}
// The CompletionRecorder captures Sema code-complete output, including context.
// It filters out ignored results (but doesn't apply fuzzy-filtering yet).
// It doesn't do scoring or conversion to CompletionItem yet, as we want to
// merge with index results first.
struct CompletionRecorder : public CodeCompleteConsumer {
CompletionRecorder(const CodeCompleteOptions &Opts)
: CodeCompleteConsumer(Opts.getClangCompleteOpts(),
/*OutputIsBinary=*/false),
CCContext(CodeCompletionContext::CCC_Other), Opts(Opts),
CCAllocator(std::make_shared<GlobalCodeCompletionAllocator>()),
CCTUInfo(CCAllocator) {}
std::vector<CodeCompletionResult> Results;
CodeCompletionContext CCContext;
Sema *CCSema = nullptr; // Sema that created the results.
// FIXME: Sema is scary. Can we store ASTContext and Preprocessor, instead?
void ProcessCodeCompleteResults(class Sema &S, CodeCompletionContext Context,
CodeCompletionResult *InResults,
unsigned NumResults) override final {
// Record the completion context.
assert(!CCSema && "ProcessCodeCompleteResults called multiple times!");
CCSema = &S;
CCContext = Context;
// Retain the results we might want.
for (unsigned I = 0; I < NumResults; ++I) {
auto &Result = InResults[I];
// Drop hidden items which cannot be found by lookup after completion.
// Exception: some items can be named by using a qualifier.
if (Result.Hidden && (!Result.Qualifier || Result.QualifierIsInformative))
continue;
if (!Opts.IncludeIneligibleResults &&
(Result.Availability == CXAvailability_NotAvailable ||
Result.Availability == CXAvailability_NotAccessible))
continue;
// Destructor completion is rarely useful, and works inconsistently.
// (s.^ completes ~string, but s.~st^ is an error).
if (dyn_cast_or_null<CXXDestructorDecl>(Result.Declaration))
continue;
Results.push_back(Result);
}
}
CodeCompletionAllocator &getAllocator() override { return *CCAllocator; }
CodeCompletionTUInfo &getCodeCompletionTUInfo() override { return CCTUInfo; }
// Returns the filtering/sorting name for Result, which must be from Results.
// Returned string is owned by this recorder (or the AST).
llvm::StringRef getName(const CodeCompletionResult &Result) {
switch (Result.Kind) {
case CodeCompletionResult::RK_Declaration:
if (auto *ID = Result.Declaration->getIdentifier())
return ID->getName();
break;
case CodeCompletionResult::RK_Keyword:
return Result.Keyword;
case CodeCompletionResult::RK_Macro:
return Result.Macro->getName();
case CodeCompletionResult::RK_Pattern:
return Result.Pattern->getTypedText();
}
auto *CCS = codeCompletionString(Result, /*IncludeBriefComments=*/false);
return CCS->getTypedText();
}
// Build a CodeCompletion string for R, which must be from Results.
// The CCS will be owned by this recorder.
CodeCompletionString *codeCompletionString(const CodeCompletionResult &R,
bool IncludeBriefComments) {
// CodeCompletionResult doesn't seem to be const-correct. We own it, anyway.
return const_cast<CodeCompletionResult &>(R).CreateCodeCompletionString(
*CCSema, CCContext, *CCAllocator, CCTUInfo, IncludeBriefComments);
}
private:
CodeCompleteOptions Opts;
std::shared_ptr<GlobalCodeCompletionAllocator> CCAllocator;
CodeCompletionTUInfo CCTUInfo;
};
// Tracks a bounded number of candidates with the best scores.
class TopN {
public:
using value_type = std::pair<CompletionCandidate, CompletionItemScores>;
static constexpr size_t Unbounded = std::numeric_limits<size_t>::max();
TopN(size_t N) : N(N) {}
// Adds a candidate to the set.
// Returns true if a candidate was dropped to get back under N.
bool push(value_type &&V) {
bool Dropped = false;
if (Heap.size() >= N) {
Dropped = true;
if (N > 0 && greater(V, Heap.front())) {
std::pop_heap(Heap.begin(), Heap.end(), greater);
Heap.back() = std::move(V);
std::push_heap(Heap.begin(), Heap.end(), greater);
}
} else {
Heap.push_back(std::move(V));
std::push_heap(Heap.begin(), Heap.end(), greater);
}
assert(Heap.size() <= N);
assert(std::is_heap(Heap.begin(), Heap.end(), greater));
return Dropped;
}
// Returns candidates from best to worst.
std::vector<value_type> items() && {
std::sort_heap(Heap.begin(), Heap.end(), greater);
assert(Heap.size() <= N);
return std::move(Heap);
}
private:
static bool greater(const value_type &L, const value_type &R) {
if (L.second.finalScore != R.second.finalScore)
return L.second.finalScore > R.second.finalScore;
return L.first.Name < R.first.Name; // Earlier name is better.
}
const size_t N;
std::vector<value_type> Heap; // Min-heap, comparator is greater().
};
class SignatureHelpCollector final : public CodeCompleteConsumer {
public:
SignatureHelpCollector(const clang::CodeCompleteOptions &CodeCompleteOpts,
SignatureHelp &SigHelp)
: CodeCompleteConsumer(CodeCompleteOpts, /*OutputIsBinary=*/false),
SigHelp(SigHelp),
Allocator(std::make_shared<clang::GlobalCodeCompletionAllocator>()),
CCTUInfo(Allocator) {}
void ProcessOverloadCandidates(Sema &S, unsigned CurrentArg,
OverloadCandidate *Candidates,
unsigned NumCandidates) override {
SigHelp.signatures.reserve(NumCandidates);
// FIXME(rwols): How can we determine the "active overload candidate"?
// Right now the overloaded candidates seem to be provided in a "best fit"
// order, so I'm not too worried about this.
SigHelp.activeSignature = 0;
assert(CurrentArg <= (unsigned)std::numeric_limits<int>::max() &&
"too many arguments");
SigHelp.activeParameter = static_cast<int>(CurrentArg);
for (unsigned I = 0; I < NumCandidates; ++I) {
const auto &Candidate = Candidates[I];
const auto *CCS = Candidate.CreateSignatureString(
CurrentArg, S, *Allocator, CCTUInfo, true);
assert(CCS && "Expected the CodeCompletionString to be non-null");
SigHelp.signatures.push_back(ProcessOverloadCandidate(Candidate, *CCS));
}
}
GlobalCodeCompletionAllocator &getAllocator() override { return *Allocator; }
CodeCompletionTUInfo &getCodeCompletionTUInfo() override { return CCTUInfo; }
private:
// FIXME(ioeric): consider moving CodeCompletionString logic here to
// CompletionString.h.
SignatureInformation
ProcessOverloadCandidate(const OverloadCandidate &Candidate,
const CodeCompletionString &CCS) const {
SignatureInformation Result;
const char *ReturnType = nullptr;
Result.documentation = getDocumentation(CCS);
for (const auto &Chunk : CCS) {
switch (Chunk.Kind) {
case CodeCompletionString::CK_ResultType:
// A piece of text that describes the type of an entity or,
// for functions and methods, the return type.
assert(!ReturnType && "Unexpected CK_ResultType");
ReturnType = Chunk.Text;
break;
case CodeCompletionString::CK_Placeholder:
// A string that acts as a placeholder for, e.g., a function call
// argument.
// Intentional fallthrough here.
case CodeCompletionString::CK_CurrentParameter: {
// A piece of text that describes the parameter that corresponds to
// the code-completion location within a function call, message send,
// macro invocation, etc.
Result.label += Chunk.Text;
ParameterInformation Info;
Info.label = Chunk.Text;
Result.parameters.push_back(std::move(Info));
break;
}
case CodeCompletionString::CK_Optional: {
// The rest of the parameters are defaulted/optional.
assert(Chunk.Optional &&
"Expected the optional code completion string to be non-null.");
Result.label +=
getOptionalParameters(*Chunk.Optional, Result.parameters);
break;
}
case CodeCompletionString::CK_VerticalSpace:
break;
default:
Result.label += Chunk.Text;
break;
}
}
if (ReturnType) {
Result.label += " -> ";
Result.label += ReturnType;
}
return Result;
}
SignatureHelp &SigHelp;
std::shared_ptr<clang::GlobalCodeCompletionAllocator> Allocator;
CodeCompletionTUInfo CCTUInfo;
}; // SignatureHelpCollector
struct SemaCompleteInput {
PathRef FileName;
const tooling::CompileCommand &Command;
PrecompiledPreamble const *Preamble;
StringRef Contents;
Position Pos;
IntrusiveRefCntPtr<vfs::FileSystem> VFS;
std::shared_ptr<PCHContainerOperations> PCHs;
};
// Invokes Sema code completion on a file.
// Callback will be invoked once completion is done, but before cleaning up.
bool semaCodeComplete(const Context &Ctx,
std::unique_ptr<CodeCompleteConsumer> Consumer,
const clang::CodeCompleteOptions &Options,
const SemaCompleteInput &Input,
llvm::function_ref<void()> Callback = nullptr) {
std::vector<const char *> ArgStrs;
for (const auto &S : Input.Command.CommandLine)
ArgStrs.push_back(S.c_str());
Input.VFS->setCurrentWorkingDirectory(Input.Command.Directory);
IgnoreDiagnostics DummyDiagsConsumer;
auto CI = createInvocationFromCommandLine(
ArgStrs,
CompilerInstance::createDiagnostics(new DiagnosticOptions,
&DummyDiagsConsumer, false),
Input.VFS);
assert(CI && "Couldn't create CompilerInvocation");
CI->getFrontendOpts().DisableFree = false;
std::unique_ptr<llvm::MemoryBuffer> ContentsBuffer =
llvm::MemoryBuffer::getMemBufferCopy(Input.Contents, Input.FileName);
// We reuse the preamble whether it's valid or not. This is a
// correctness/performance tradeoff: building without a preamble is slow, and
// completion is latency-sensitive.
if (Input.Preamble) {
auto Bounds =
ComputePreambleBounds(*CI->getLangOpts(), ContentsBuffer.get(), 0);
// FIXME(ibiryukov): Remove this call to CanReuse() after we'll fix
// clients relying on getting stats for preamble files during code
// completion.
// Note that results of CanReuse() are ignored, see the comment above.
Input.Preamble->CanReuse(*CI, ContentsBuffer.get(), Bounds,
Input.VFS.get());
}
auto Clang = prepareCompilerInstance(
std::move(CI), Input.Preamble, std::move(ContentsBuffer),
std::move(Input.PCHs), std::move(Input.VFS), DummyDiagsConsumer);
auto &DiagOpts = Clang->getDiagnosticOpts();
DiagOpts.IgnoreWarnings = true;
auto &FrontendOpts = Clang->getFrontendOpts();
FrontendOpts.SkipFunctionBodies = true;
FrontendOpts.CodeCompleteOpts = Options;
FrontendOpts.CodeCompletionAt.FileName = Input.FileName;
FrontendOpts.CodeCompletionAt.Line = Input.Pos.line + 1;
FrontendOpts.CodeCompletionAt.Column = Input.Pos.character + 1;
Clang->setCodeCompletionConsumer(Consumer.release());
SyntaxOnlyAction Action;
if (!Action.BeginSourceFile(*Clang, Clang->getFrontendOpts().Inputs[0])) {
log(Ctx, "BeginSourceFile() failed when running codeComplete for " +
Input.FileName);
return false;
}
if (!Action.Execute()) {
log(Ctx,
"Execute() failed when running codeComplete for " + Input.FileName);
return false;
}
if (Callback)
Callback();
Action.EndSourceFile();
return true;
}
// Should we perform index-based completion in this context?
// FIXME: consider allowing completion, but restricting the result types.
bool allowIndex(enum CodeCompletionContext::Kind K) {
switch (K) {
case CodeCompletionContext::CCC_TopLevel:
case CodeCompletionContext::CCC_ObjCInterface:
case CodeCompletionContext::CCC_ObjCImplementation:
case CodeCompletionContext::CCC_ObjCIvarList:
case CodeCompletionContext::CCC_ClassStructUnion:
case CodeCompletionContext::CCC_Statement:
case CodeCompletionContext::CCC_Expression:
case CodeCompletionContext::CCC_ObjCMessageReceiver:
case CodeCompletionContext::CCC_EnumTag:
case CodeCompletionContext::CCC_UnionTag:
case CodeCompletionContext::CCC_ClassOrStructTag:
case CodeCompletionContext::CCC_ObjCProtocolName:
case CodeCompletionContext::CCC_Namespace:
case CodeCompletionContext::CCC_Type:
case CodeCompletionContext::CCC_Name: // FIXME: why does ns::^ give this?
case CodeCompletionContext::CCC_PotentiallyQualifiedName:
case CodeCompletionContext::CCC_ParenthesizedExpression:
case CodeCompletionContext::CCC_ObjCInterfaceName:
case CodeCompletionContext::CCC_ObjCCategoryName:
return true;
case CodeCompletionContext::CCC_Other: // Be conservative.
case CodeCompletionContext::CCC_OtherWithMacros:
case CodeCompletionContext::CCC_DotMemberAccess:
case CodeCompletionContext::CCC_ArrowMemberAccess:
case CodeCompletionContext::CCC_ObjCPropertyAccess:
case CodeCompletionContext::CCC_MacroName:
case CodeCompletionContext::CCC_MacroNameUse:
case CodeCompletionContext::CCC_PreprocessorExpression:
case CodeCompletionContext::CCC_PreprocessorDirective:
case CodeCompletionContext::CCC_NaturalLanguage:
case CodeCompletionContext::CCC_SelectorName:
case CodeCompletionContext::CCC_TypeQualifiers:
case CodeCompletionContext::CCC_ObjCInstanceMessage:
case CodeCompletionContext::CCC_ObjCClassMessage:
case CodeCompletionContext::CCC_Recovery:
return false;
}
llvm_unreachable("unknown code completion context");
}
} // namespace
clang::CodeCompleteOptions CodeCompleteOptions::getClangCompleteOpts() const {
clang::CodeCompleteOptions Result;
Result.IncludeCodePatterns = EnableSnippets && IncludeCodePatterns;
Result.IncludeMacros = IncludeMacros;
Result.IncludeGlobals = true;
Result.IncludeBriefComments = IncludeBriefComments;
// When an is used, Sema is responsible for completing the main file,
// the index can provide results from the preamble.
// Tell Sema not to deserialize the preamble to look for results.
Result.LoadExternal = !Index;
return Result;
}
// Runs Sema-based (AST) and Index-based completion, returns merged results.
//
// There are a few tricky considerations:
// - the AST provides information needed for the index query (e.g. which
// namespaces to search in). So Sema must start first.
// - we only want to return the top results (Opts.Limit).
// Building CompletionItems for everything else is wasteful, so we want to
// preserve the "native" format until we're done with scoring.
// - the data underlying Sema completion items is owned by the AST and various
// other arenas, which must stay alive for us to build CompletionItems.
// - we may get duplicate results from Sema and the Index, we need to merge.
//
// So we start Sema completion first, but defer its cleanup until we're done.
// We use the Sema context information to query the index.
// Then we merge the two result sets, producing items that are Sema/Index/Both.
// These items are scored, and the top N are synthesized into the LSP response.
// Finally, we can clean up the data structures created by Sema completion.
//
// Main collaborators are:
// - semaCodeComplete sets up the compiler machinery to run code completion.
// - CompletionRecorder captures Sema completion results, including context.
// - SymbolIndex (Opts.Index) provides index completion results as Symbols
// - CompletionCandidates are the result of merging Sema and Index results.
// Each candidate points to an underlying CodeCompletionResult (Sema), a
// Symbol (Index), or both. It computes the result quality score.
// CompletionCandidate also does conversion to CompletionItem (at the end).
// - FuzzyMatcher scores how the candidate matches the partial identifier.
// This score is combined with the result quality score for the final score.
// - TopN determines the results with the best score.
class CodeCompleteFlow {
const Context &Ctx;
const CodeCompleteOptions &Opts;
// Sema takes ownership of Recorder. Recorder is valid until Sema cleanup.
std::unique_ptr<CompletionRecorder> RecorderOwner;
CompletionRecorder &Recorder;
int NSema = 0, NIndex = 0, NBoth = 0; // Counters for logging.
bool Incomplete = false; // Would more be available with a higher limit?
llvm::Optional<FuzzyMatcher> Filter; // Initialized once Sema runs.
public:
// A CodeCompleteFlow object is only useful for calling run() exactly once.
CodeCompleteFlow(const Context &Ctx, const CodeCompleteOptions &Opts)
: Ctx(Ctx), Opts(Opts), RecorderOwner(new CompletionRecorder(Opts)),
Recorder(*RecorderOwner) {}
CompletionList run(const SemaCompleteInput &SemaCCInput) && {
// We run Sema code completion first. It builds an AST and calculates:
// - completion results based on the AST. These are saved for merging.
// - partial identifier and context. We need these for the index query.
CompletionList Output;
semaCodeComplete(Ctx, std::move(RecorderOwner), Opts.getClangCompleteOpts(),
SemaCCInput, [&] {
if (Recorder.CCSema)
Output = runWithSema();
else
log(Ctx, "Code complete: no Sema callback, 0 results");
});
log(Ctx,
llvm::formatv("Code complete: {0} results from Sema, {1} from Index, "
"{2} matched, {3} returned{4}.",
NSema, NIndex, NBoth, Output.items.size(),
Output.isIncomplete ? " (incomplete)" : ""));
assert(!Opts.Limit || Output.items.size() <= Opts.Limit);
// We don't assert that isIncomplete means we hit a limit.
// Indexes may choose to impose their own limits even if we don't have one.
return Output;
}
private:
// This is called by run() once Sema code completion is done, but before the
// Sema data structures are torn down. It does all the real work.
CompletionList runWithSema() {
Filter = FuzzyMatcher(
Recorder.CCSema->getPreprocessor().getCodeCompletionFilter());
// Sema provides the needed context to query the index.
// FIXME: in addition to querying for extra/overlapping symbols, we should
// explicitly request symbols corresponding to Sema results.
// We can use their signals even if the index can't suggest them.
// We must copy index results to preserve them, but there are at most Limit.
auto IndexResults = queryIndex();
// Merge Sema and Index results, score them, and pick the winners.
auto Top = mergeResults(Recorder.Results, IndexResults);
// Convert the results to the desired LSP structs.
CompletionList Output;
for (auto &C : Top)
Output.items.push_back(toCompletionItem(C.first, C.second));
Output.isIncomplete = Incomplete;
return Output;
}
SymbolSlab queryIndex() {
if (!Opts.Index || !allowIndex(Recorder.CCContext.getKind()))
return SymbolSlab();
SymbolSlab::Builder ResultsBuilder;
// Build the query.
FuzzyFindRequest Req;
Req.Query = Filter->pattern();
Req.Scopes =
getQueryScopes(Recorder.CCContext, Recorder.CCSema->getSourceManager());
log(Ctx, llvm::formatv(
"Code complete: fuzzyFind(\"{0}\", Scopes: [{1}]", Req.Query,
llvm::join(Req.Scopes.begin(), Req.Scopes.end(), ",")));
// Run the query against the index.
Incomplete |= !Opts.Index->fuzzyFind(
Ctx, Req, [&](const Symbol &Sym) { ResultsBuilder.insert(Sym); });
return std::move(ResultsBuilder).build();
}
// Merges the Sema and Index results where possible, scores them, and
// returns the top results from best to worst.
std::vector<std::pair<CompletionCandidate, CompletionItemScores>>
mergeResults(const std::vector<CodeCompletionResult> &SemaResults,
const SymbolSlab &IndexResults) {
// We only keep the best N results at any time, in "native" format.
TopN Top(Opts.Limit == 0 ? TopN::Unbounded : Opts.Limit);
llvm::DenseSet<const Symbol *> UsedIndexResults;
auto CorrespondingIndexResult =
[&](const CodeCompletionResult &SemaResult) -> const Symbol * {
if (auto SymID = getSymbolID(SemaResult)) {
auto I = IndexResults.find(*SymID);
if (I != IndexResults.end()) {
UsedIndexResults.insert(&*I);
return &*I;
}
}
return nullptr;
};
// Emit all Sema results, merging them with Index results if possible.
for (auto &SemaResult : Recorder.Results)
addCandidate(Top, &SemaResult, CorrespondingIndexResult(SemaResult));
// Now emit any Index-only results.
for (const auto &IndexResult : IndexResults) {
if (UsedIndexResults.count(&IndexResult))
continue;
addCandidate(Top, /*SemaResult=*/nullptr, &IndexResult);
}
return std::move(Top).items();
}
// Scores a candidate and adds it to the TopN structure.
void addCandidate(TopN &Candidates, const CodeCompletionResult *SemaResult,
const Symbol *IndexResult) {
CompletionCandidate C;
C.SemaResult = SemaResult;
C.IndexResult = IndexResult;
C.Name = IndexResult ? IndexResult->Name : Recorder.getName(*SemaResult);
CompletionItemScores Scores;
if (auto FuzzyScore = Filter->match(C.Name))
Scores.filterScore = *FuzzyScore;
else
return;
Scores.symbolScore = C.score();
// We score candidates by multiplying symbolScore ("quality" of the result)
// with filterScore (how well it matched the query).
// This is sensitive to the distribution of both component scores!
Scores.finalScore = Scores.filterScore * Scores.symbolScore;
NSema += bool(SemaResult);
NIndex += bool(IndexResult);
NBoth += SemaResult && IndexResult;
Incomplete |= Candidates.push({C, Scores});
}
CompletionItem toCompletionItem(const CompletionCandidate &Candidate,
const CompletionItemScores &Scores) {
CodeCompletionString *SemaCCS = nullptr;
if (auto *SR = Candidate.SemaResult)
SemaCCS = Recorder.codeCompletionString(*SR, Opts.IncludeBriefComments);
return Candidate.build(Scores, Opts, SemaCCS);
}
};
CompletionList codeComplete(const Context &Ctx, PathRef FileName,
const tooling::CompileCommand &Command,
PrecompiledPreamble const *Preamble,
StringRef Contents, Position Pos,
IntrusiveRefCntPtr<vfs::FileSystem> VFS,
std::shared_ptr<PCHContainerOperations> PCHs,
CodeCompleteOptions Opts) {
return CodeCompleteFlow(Ctx, Opts).run(
{FileName, Command, Preamble, Contents, Pos, VFS, PCHs});
}
SignatureHelp signatureHelp(const Context &Ctx, PathRef FileName,
const tooling::CompileCommand &Command,
PrecompiledPreamble const *Preamble,
StringRef Contents, Position Pos,
IntrusiveRefCntPtr<vfs::FileSystem> VFS,
std::shared_ptr<PCHContainerOperations> PCHs) {
SignatureHelp Result;
clang::CodeCompleteOptions Options;
Options.IncludeGlobals = false;
Options.IncludeMacros = false;
Options.IncludeCodePatterns = false;
Options.IncludeBriefComments = true;
semaCodeComplete(
Ctx, llvm::make_unique<SignatureHelpCollector>(Options, Result), Options,
{FileName, Command, Preamble, Contents, Pos, std::move(VFS),
std::move(PCHs)});
return Result;
}
} // namespace clangd
} // namespace clang
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