[Concepts] Constraint Satisfaction Caching
Add a simple cache for constraint satisfaction results. Whether or not this simple caching
would be permitted in final C++2a is currently being discussed but it is required for
acceptable performance so we use it in the meantime, with the possibility of adding some
cache invalidation mechanisms later.
Differential Revision: https://reviews.llvm.org/D72552
diff --git a/clang/lib/Sema/SemaConcept.cpp b/clang/lib/Sema/SemaConcept.cpp
index 93e5b45..81601b0 100755
--- a/clang/lib/Sema/SemaConcept.cpp
+++ b/clang/lib/Sema/SemaConcept.cpp
@@ -272,36 +272,56 @@
return false;
}
-bool Sema::CheckConstraintSatisfaction(TemplateDecl *Template,
- ArrayRef<const Expr *> ConstraintExprs,
- ArrayRef<TemplateArgument> TemplateArgs,
- SourceRange TemplateIDRange,
- ConstraintSatisfaction &Satisfaction) {
- return ::CheckConstraintSatisfaction(*this, Template, ConstraintExprs,
- TemplateArgs, TemplateIDRange,
- Satisfaction);
-}
+bool Sema::CheckConstraintSatisfaction(
+ NamedDecl *Template, ArrayRef<const Expr *> ConstraintExprs,
+ ArrayRef<TemplateArgument> TemplateArgs, SourceRange TemplateIDRange,
+ ConstraintSatisfaction &OutSatisfaction) {
+ if (ConstraintExprs.empty()) {
+ OutSatisfaction.IsSatisfied = true;
+ return false;
+ }
-bool
-Sema::CheckConstraintSatisfaction(ClassTemplatePartialSpecializationDecl* Part,
- ArrayRef<const Expr *> ConstraintExprs,
- ArrayRef<TemplateArgument> TemplateArgs,
- SourceRange TemplateIDRange,
- ConstraintSatisfaction &Satisfaction) {
- return ::CheckConstraintSatisfaction(*this, Part, ConstraintExprs,
- TemplateArgs, TemplateIDRange,
- Satisfaction);
-}
+ llvm::FoldingSetNodeID ID;
+ void *InsertPos;
+ ConstraintSatisfaction *Satisfaction = nullptr;
+ if (LangOpts.ConceptSatisfactionCaching) {
+ ConstraintSatisfaction::Profile(ID, Context, Template, TemplateArgs);
+ Satisfaction = SatisfactionCache.FindNodeOrInsertPos(ID, InsertPos);
+ if (Satisfaction) {
+ OutSatisfaction = *Satisfaction;
+ return false;
+ }
+ Satisfaction = new ConstraintSatisfaction(Template, TemplateArgs);
+ } else {
+ Satisfaction = &OutSatisfaction;
+ }
+ bool Failed;
+ if (auto *T = dyn_cast<TemplateDecl>(Template))
+ Failed = ::CheckConstraintSatisfaction(*this, T, ConstraintExprs,
+ TemplateArgs, TemplateIDRange,
+ *Satisfaction);
+ else if (auto *P =
+ dyn_cast<ClassTemplatePartialSpecializationDecl>(Template))
+ Failed = ::CheckConstraintSatisfaction(*this, P, ConstraintExprs,
+ TemplateArgs, TemplateIDRange,
+ *Satisfaction);
+ else
+ Failed = ::CheckConstraintSatisfaction(
+ *this, cast<VarTemplatePartialSpecializationDecl>(Template),
+ ConstraintExprs, TemplateArgs, TemplateIDRange, *Satisfaction);
+ if (Failed) {
+ if (LangOpts.ConceptSatisfactionCaching)
+ delete Satisfaction;
+ return true;
+ }
-bool
-Sema::CheckConstraintSatisfaction(VarTemplatePartialSpecializationDecl* Partial,
- ArrayRef<const Expr *> ConstraintExprs,
- ArrayRef<TemplateArgument> TemplateArgs,
- SourceRange TemplateIDRange,
- ConstraintSatisfaction &Satisfaction) {
- return ::CheckConstraintSatisfaction(*this, Partial, ConstraintExprs,
- TemplateArgs, TemplateIDRange,
- Satisfaction);
+ if (LangOpts.ConceptSatisfactionCaching) {
+ // We cannot use InsertNode here because CheckConstraintSatisfaction might
+ // have invalidated it.
+ SatisfactionCache.InsertNode(Satisfaction);
+ OutSatisfaction = *Satisfaction;
+ }
+ return false;
}
bool Sema::CheckConstraintSatisfaction(const Expr *ConstraintExpr,