[PATCH] D125675: Optimise findRefs for XRefs and docHighlights

[Kadir Cetinkaya via Phabricator via cfe-commits]

kadircet accepted this revision.
kadircet added a comment.
This revision is now accepted and ready to land.

thanks for noticing this, LGTM!



================
Comment at: clang-tools-extra/clangd/XRefs.cpp:961
   const ParsedAST *
-  const llvm::DenseSet<SymbolID> &TargetIDs;
+  llvm::DenseMap<const Decl *, SymbolID> TargetDeclAndID;
 };
----------------
s/TargetDeclAndID/TargetDeclToID


================
Comment at: clang-tools-extra/clangd/XRefs.cpp:965
 std::vector<ReferenceFinder::Reference>
-findRefs(const llvm::DenseSet<SymbolID> &IDs, ParsedAST &AST, bool PerToken) {
-  ReferenceFinder RefFinder(AST, IDs, PerToken);
+findRefs(const llvm::DenseSet<const Decl *> &TargetDecls, ParsedAST &AST,
+         bool PerToken) {
----------------
i'd actually update the interface here to just take an `ArrayRef<Decl*>` as targets, as we're currently building those extra dense sets just to iterate over them. both `allTargetDecls` and `getDeclAtPosition` (which uses `allTargetDecls` underneath) are guaranteed to not return duplicates. So we can pass their result directly here. Up to you though.


================
Comment at: clang-tools-extra/clangd/XRefs.cpp:1919
   // If there's a specific type alias, point at that rather than unwrapping.
-  if (const auto* TDT = T->getAs<TypedefType>())
+  if (const auto *TDT = T->getAs<TypedefType>())
     return QualType(TDT, 0);
----------------
can you revert this change?


================
Comment at: clang-tools-extra/clangd/XRefs.cpp:951
       if (const auto *Tok = TB.spelledTokenAt(L))
-        References.push_back({*Tok, Roles, ID});
+        References.push_back({*Tok, Roles, getSymbolID(D)});
     }
----------------
usaxena95 wrote:
> kadircet wrote:
> > we're still calling getsymbolid here lots of times, for probably the same symbol.
> > 
> > as discussed, what about building a lookup table on construction from canonicaldecl to symbolid and use that lookup table instead of calling getsymbolid over and over here?
> I don't mind adding a lookup table for this but this is not huge, only O(#ref) as compared to previous O(size of TU). 
> 
> 
thanks. previous one was also size of main file, not the whole TU (if you see indications of the latter in a different application let's take a look at that separately).

but there are big enough files in which you can have thousands of references to stringref and what not. so i think this actually matters.


================
Comment at: clang-tools-extra/clangd/XRefs.cpp:1255
+           targetDecl(N->ASTNode, Relations, AST.getHeuristicResolver())) {
+        TargetDecls.insert(D);
+      }
----------------
usaxena95 wrote:
> kadircet wrote:
> > i mean directly inserting canonicaldecls here.
> This would make it messy to duplicate this on each end of the call. 
> + This has potential of introducing bugs in future findRef calls if we don't pass the canonical decls. Or we would have to assert that we only get canonical decls.
> I think this is an implementation detail of findRefs and should not be visible outside its API for simplicity.
SG, it's an implementation detail of this file already so not a big deal. But moreover we're building a separate lookup table already now, so obsolete.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D125675/new/

https://reviews.llvm.org/D125675