averello/swift-mirror
1
0
Fork 0
mirror of https://github.com/apple/swift.git synced 2025-12-21 12:14:44 +01:00
Code Issues Packages Projects Releases Wiki Activity

Remove SimpleRequest::breakCycle

Browse Source 
This patch removes the need for Request objects to provide a default
cycle-breaking value, instead opting to return llvm::Expected so clients
must handle a cycle failure explicitly.

Currently, all clients do the 'default' behavior, but this opens the
possibility for future requests to handle failures explicitly.
This commit is contained in:
Harlan Haskins
2018-08-01 13:46:21 -07:00
committed by Harlan Haskins
parent be0e1643d6
commit 5a6985f39e
15 changed files with 261 additions and 188 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
include/swift/AST/AccessRequests.h
View File

@@ -42,11 +42,11 @@ private:
friend class SimpleRequest;
// Evaluation.
AccessLevel evaluate(Evaluator &evaluator, ValueDecl *decl) const;
llvm::Expected<AccessLevel> evaluate(Evaluator &evaluator,
ValueDecl *decl) const;
public:
// Cycle handling
AccessLevel breakCycle() const { return AccessLevel::Private; }
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;
@@ -71,11 +71,11 @@ private:
friend class SimpleRequest;
// Evaluation.
AccessLevel evaluate(Evaluator &evaluator, AbstractStorageDecl *decl) const;
llvm::Expected<AccessLevel>
evaluate(Evaluator &evaluator, AbstractStorageDecl *decl) const;
public:
// Cycle handling
AccessLevel breakCycle() const { return AccessLevel::Private; }
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;
@@ -98,14 +98,11 @@ private:
friend class SimpleRequest;
// Evaluation.
DefaultAndMax
llvm::Expected<DefaultAndMax>
evaluate(Evaluator &evaluator, ExtensionDecl *decl) const;
public:
// Cycle handling
DefaultAndMax
breakCycle() const { return std::make_pair(AccessLevel::Private,
AccessLevel::Private); }
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;

87
include/swift/AST/Evaluator.h
View File

@@ -25,6 +25,7 @@
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/PrettyStackTrace.h"
#include <string>
#include <tuple>
@@ -52,7 +53,7 @@ using AbstractRequestFunction = void(void);
/// Form the specific request function for the given request type.
template<typename Request>
using RequestFunction =
typename Request::OutputType(const Request &, Evaluator &);
llvm::Expected<typename Request::OutputType>(const Request &, Evaluator &);
/// Pretty stack trace handler for an arbitrary request.
template<typename Request>
@@ -69,6 +70,49 @@ public:
}
};
/// An llvm::ErrorInfo container for a request in which a cycle was detected
/// and diagnosed.
template <typename Request>
struct CyclicalRequestError :
public llvm::ErrorInfo<CyclicalRequestError<Request>> {
public:
static char ID;
const Request &request;
CyclicalRequestError(const Request &request): request(request) {}
virtual void log(llvm::raw_ostream &out) const {
out << "Cycle detected:\n";
simple_display(out, request);
out << "\n";
}
virtual std::error_code convertToErrorCode() const {
// This is essentially unused, but is a temporary requirement for
// llvm::ErrorInfo subclasses.
llvm_unreachable("shouldn't get std::error_code from CyclicalRequestError");
}
};
template <typename Request>
char CyclicalRequestError<Request>::ID = '\0';
/// Evaluates a given request or returns a default value if a cycle is detected.
template <typename Request>
typename Request::OutputType
evaluateOrDefault(
Evaluator &eval, Request req, typename Request::OutputType def) {
auto result = eval(req);
if (auto err = result.takeError()) {
llvm::handleAllErrors(std::move(err),
[](const CyclicalRequestError<Request> &E) {
// cycle detected
});
return def;
}
return *result;
}
/// Report that a request of the given kind is being evaluated, so it
/// can be recorded by the stats reporter.
template<typename Request>
@@ -101,7 +145,6 @@ void reportEvaluatedRequest(UnifiedStatsReporter &stats,
///
/// void diagnoseCycle(DiagnosticEngine &diags) const;
/// void noteCycleStep(DiagnosticEngine &diags) const;
/// OutputType breakCycle() const;
/// - Caching policy:
///
/// static const bool isEverCached;
@@ -211,10 +254,13 @@ public:
/// Evaluate the given request and produce its result,
/// consulting/populating the cache as required.
template<typename Request>
typename Request::OutputType operator()(const Request &request) {
llvm::Expected<typename Request::OutputType>
operator()(const Request &request) {
// Check for a cycle.
if (checkDependency(AnyRequest(request)))
return request.breakCycle();
if (checkDependency(AnyRequest(request))) {
return llvm::Error(
llvm::make_unique<CyclicalRequestError<Request>>(request));
}
// Make sure we remove this from the set of active requests once we're
// done.
@@ -232,9 +278,10 @@ public:
/// Use this to describe cases where there are multiple (known)
/// requests that all need to be satisfied.
template<typename ...Requests>
std::tuple<typename Requests::OutputType...>
std::tuple<llvm::Expected<typename Requests::OutputType>...>
operator()(const Requests &...requests) {
return std::tuple<typename Requests::OutputType...>((*this)(requests)...);
return std::tuple<llvm::Expected<typename Requests::OutputType>...>(
(*this)(requests)...);
}
/// Clear the cache stored within this evaluator.
@@ -260,7 +307,8 @@ private:
/// be cached.
template<typename Request,
typename std::enable_if<Request::isEverCached>::type * = nullptr>
typename Request::OutputType getResult(const Request &request) {
llvm::Expected<typename Request::OutputType>
getResult(const Request &request) {
// The request can be cached, but check a predicate to determine
// whether this particular instance is cached. This allows more
// fine-grained control over which instances get cache.
@@ -274,13 +322,15 @@ private:
/// will never be cached.
template<typename Request,
typename std::enable_if<!Request::isEverCached>::type * = nullptr>
typename Request::OutputType getResult(const Request &request) {
llvm::Expected<typename Request::OutputType>
getResult(const Request &request) {
return getResultUncached(request);
}
/// Produce the result of the request without caching.
template<typename Request>
typename Request::OutputType getResultUncached(const Request &request) {
llvm::Expected<typename Request::OutputType>
getResultUncached(const Request &request) {
// Clear out the dependencies on this request; we're going to recompute
// them now anyway.
dependencies[AnyRequest(request)].clear();
@@ -298,7 +348,8 @@ private:
/// and detect recursion.
template<typename Request,
typename std::enable_if<Request::hasExternalCache>::type * = nullptr>
typename Request::OutputType getResultCached(const Request &request) {
llvm::Expected<typename Request::OutputType>
getResultCached(const Request &request) {
// If there is a cached result, return it.
if (auto cached = request.getCachedResult())
return *cached;
@@ -306,8 +357,11 @@ private:
// Compute the result.
auto result = getResultUncached(request);
// Cache the result.
request.cacheResult(result);
// Cache the result if applicable.
if (!result)
return result;
request.cacheResult(*result);
// Return it.
return result;
@@ -319,6 +373,9 @@ private:
typename Request,
typename std::enable_if<!Request::hasExternalCache>::type * = nullptr>
typename Request::OutputType getResultCached(const Request &request) {
llvm::Expected<typename Request::OutputType>
getResultCached(const Request &request) {
AnyRequest anyRequest{request};
// If we already have an entry for this request in the cache, return it.
auto known = cache.find_as(request);
if (known != cache.end()) {
@@ -327,9 +384,11 @@ private:
// Compute the result.
auto result = getResultUncached(request);
if (!result)
return result;
// Cache the result.
cache.insert({AnyRequest(request), result});
cache.insert({AnyRequest(request), *result});
return result;
}

10
include/swift/AST/NameLookupRequests.h
View File

@@ -81,7 +81,6 @@ public:
bool isCached() const { return true; }
// Cycle handling
DirectlyReferencedTypeDecls breakCycle() const { return { }; }
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;
};
@@ -127,7 +126,6 @@ public:
bool isCached() const { return true; }
// Cycle handling
DirectlyReferencedTypeDecls breakCycle() const { return { }; }
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;
};
@@ -145,14 +143,14 @@ private:
friend class SimpleRequest;
// Evaluation.
ClassDecl *evaluate(Evaluator &evaluator, NominalTypeDecl *subject) const;
llvm::Expected<ClassDecl *>
evaluate(Evaluator &evaluator, NominalTypeDecl *subject) const;
public:
// Caching
bool isCached() const { return true; }
// Cycle handling
ClassDecl *breakCycle() const { return nullptr; }
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;
};
@@ -170,7 +168,8 @@ private:
friend class SimpleRequest;
// Evaluation.
NominalTypeDecl *evaluate(Evaluator &evaluator, ExtensionDecl *ext) const;
llvm::Expected<NominalTypeDecl *>
evaluate(Evaluator &evaluator, ExtensionDecl *ext) const;
public:
// Separate caching.
@@ -179,7 +178,6 @@ public:
void cacheResult(NominalTypeDecl *value) const;
// Cycle handling
NominalTypeDecl *breakCycle() const { return nullptr; }
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;
};

18
include/swift/AST/SimpleRequest.h
View File

@@ -54,15 +54,9 @@ enum class CacheKind {
///
/// The \c Derived class needs to implement several operations. The most
/// important one takes an evaluator and the input values, then computes the
/// final result:
/// final result, optionally bubbling up errors from recursive evaulations:
/// \code
/// Output evaluate(Evaluator &evaluator, Inputs...) const;
/// \endcode
///
/// The \c Derived class will also need to implement an operation to break a
/// cycle if one is found, i.e.,
/// \code
/// OutputType breakCycle() const;
/// llvm::Expected<Output> evaluate(Evaluator &evaluator, Inputs...) const;
/// \endcode
///
/// Cycle diagnostics can be handled in one of two ways. Either the \c Derived
@@ -103,8 +97,8 @@ class SimpleRequest {
}
template<size_t ...Indices>
Output callDerived(Evaluator &evaluator,
llvm::index_sequence<Indices...>) const {
llvm::Expected<Output>
callDerived(Evaluator &evaluator, llvm::index_sequence<Indices...>) const {
static_assert(sizeof...(Indices) > 0, "Subclass must define evaluate()");
return asDerived().evaluate(evaluator, std::get<Indices>(storage)...);
}
@@ -131,8 +125,8 @@ public:
: storage(inputs...) { }
/// Request evaluation function that will be registered with the evaluator.
static OutputType evaluateRequest(const Derived &request,
Evaluator &evaluator) {
static llvm::Expected<OutputType>
evaluateRequest(const Derived &request, Evaluator &evaluator) {
return request.callDerived(evaluator,
llvm::index_sequence_for<Inputs...>());
}

27
include/swift/AST/TypeCheckRequests.h
View File

@@ -52,13 +52,13 @@ private:
friend class SimpleRequest;
// Evaluation.
Type evaluate(Evaluator &evaluator,
llvm::PointerUnion<TypeDecl *, ExtensionDecl *> decl,
unsigned index) const;
llvm::Expected<Type>
evaluate(Evaluator &evaluator,
llvm::PointerUnion<TypeDecl *, ExtensionDecl *> decl,
unsigned index) const;
public:
// Cycle handling
Type breakCycle() const { return Type(); }
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;
@@ -81,11 +81,11 @@ private:
friend class SimpleRequest;
// Evaluation.
Type evaluate(Evaluator &evaluator, NominalTypeDecl *classDecl) const;
llvm::Expected<Type>
evaluate(Evaluator &evaluator, NominalTypeDecl *classDecl) const;
public:
// Cycle handling
Type breakCycle() const { return Type(); }
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;
@@ -108,11 +108,11 @@ private:
friend class SimpleRequest;
// Evaluation.
Type evaluate(Evaluator &evaluator, EnumDecl *enumDecl) const;
llvm::Expected<Type>
evaluate(Evaluator &evaluator, EnumDecl *enumDecl) const;
public:
// Cycle handling
Type breakCycle() const { return Type(); }
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;
@@ -136,12 +136,11 @@ private:
friend class SimpleRequest;
// Evaluation.
llvm::TinyPtrVector<ValueDecl *> evaluate(Evaluator &evaluator,
ValueDecl *decl) const;
llvm::Expected<llvm::TinyPtrVector<ValueDecl *>>
evaluate(Evaluator &evaluator, ValueDecl *decl) const;
public:
// Cycle handling
llvm::TinyPtrVector<ValueDecl *> breakCycle() const { return { }; }
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;
@@ -164,11 +163,10 @@ private:
friend class SimpleRequest;
// Evaluation.
bool evaluate(Evaluator &evaluator, ValueDecl *decl) const;
llvm::Expected<bool> evaluate(Evaluator &evaluator, ValueDecl *decl) const;
public:
// Cycle handling
bool breakCycle() const;
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;
@@ -191,11 +189,10 @@ private:
friend class SimpleRequest;
// Evaluation.
bool evaluate(Evaluator &evaluator, ValueDecl *decl) const;
llvm::Expected<bool> evaluate(Evaluator &evaluator, ValueDecl *decl) const;
public:
// Cycle handling
bool breakCycle() const;
void diagnoseCycle(DiagnosticEngine &diags) const;
void noteCycleStep(DiagnosticEngine &diags) const;