r242253 - [modules] Switch to the normal reverse postorder visitation algorithm when computing redeclaration chains.
Richard Smith
richard-llvm at metafoo.co.uk
Tue Jul 14 17:02:41 PDT 2015
Author: rsmith
Date: Tue Jul 14 19:02:40 2015
New Revision: 242253
URL: http://llvm.org/viewvc/llvm-project?rev=242253&view=rev
Log:
[modules] Switch to the normal reverse postorder visitation algorithm when computing redeclaration chains.
Modified:
cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
cfe/trunk/lib/Serialization/ASTWriter.cpp
Modified: cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTReaderDecl.cpp?rev=242253&r1=242252&r2=242253&view=diff
==============================================================================
--- cfe/trunk/lib/Serialization/ASTReaderDecl.cpp (original)
+++ cfe/trunk/lib/Serialization/ASTReaderDecl.cpp Tue Jul 14 19:02:40 2015
@@ -3423,19 +3423,19 @@ namespace {
GlobalDeclID CanonID)
: Reader(Reader), SearchDecls(SearchDecls), Deserialized(Deserialized),
CanonID(CanonID) {
- // Ensure that the canonical ID goes at the start of the chain.
- addToChain(Reader.GetDecl(CanonID));
+ assert(std::is_sorted(SearchDecls.begin(), SearchDecls.end()));
}
- static ModuleManager::DFSPreorderControl
- visitPreorder(ModuleFile &M, void *UserData) {
- return static_cast<RedeclChainVisitor *>(UserData)->visitPreorder(M);
+ static bool visit(ModuleFile &M, void *UserData) {
+ return static_cast<RedeclChainVisitor*>(UserData)->visit(M);
}
-
- static bool visitPostorder(ModuleFile &M, void *UserData) {
- return static_cast<RedeclChainVisitor *>(UserData)->visitPostorder(M);
+
+ /// Get the chain, in order from newest to oldest.
+ ArrayRef<Decl *> getChain() const {
+ return Chain;
}
+ private:
void addToChain(Decl *D) {
if (!D)
return;
@@ -3444,75 +3444,82 @@ namespace {
Chain.push_back(D);
}
- void searchForID(ModuleFile &M, GlobalDeclID GlobalID) {
- // Map global ID of the first declaration down to the local ID
- // used in this module file.
- DeclID ID = Reader.mapGlobalIDToModuleFileGlobalID(M, GlobalID);
- if (!ID)
- return;
-
- // If the search decl was from this module, add it to the chain before any
- // of its redeclarations in this module or users of it, and after any from
- // imported modules.
- if (CanonID != GlobalID && Reader.isDeclIDFromModule(GlobalID, M))
- addToChain(Reader.GetDecl(GlobalID));
-
+ llvm::Optional<unsigned> findRedeclOffset(ModuleFile &M, DeclID LocalID) {
// Perform a binary search to find the local redeclarations for this
// declaration (if any).
- const LocalRedeclarationsInfo Compare = { ID, 0 };
- const LocalRedeclarationsInfo *Result
- = std::lower_bound(M.RedeclarationsMap,
- M.RedeclarationsMap + M.LocalNumRedeclarationsInMap,
- Compare);
- if (Result == M.RedeclarationsMap + M.LocalNumRedeclarationsInMap ||
- Result->FirstID != ID)
- return;
-
- // Dig out all of the redeclarations.
- unsigned Offset = Result->Offset;
- unsigned N = M.RedeclarationChains[Offset];
- M.RedeclarationChains[Offset++] = 0; // Don't try to deserialize again
- for (unsigned I = 0; I != N; ++I)
- addToChain(Reader.GetLocalDecl(M, M.RedeclarationChains[Offset++]));
- }
-
- bool needsToVisitImports(ModuleFile &M, GlobalDeclID GlobalID) {
- DeclID ID = Reader.mapGlobalIDToModuleFileGlobalID(M, GlobalID);
- if (!ID)
- return false;
-
- const LocalRedeclarationsInfo Compare = {ID, 0};
+ const LocalRedeclarationsInfo Compare = { LocalID, 0 };
const LocalRedeclarationsInfo *Result = std::lower_bound(
M.RedeclarationsMap,
M.RedeclarationsMap + M.LocalNumRedeclarationsInMap, Compare);
if (Result == M.RedeclarationsMap + M.LocalNumRedeclarationsInMap ||
- Result->FirstID != ID) {
- return true;
- }
- unsigned Offset = Result->Offset;
- unsigned N = M.RedeclarationChains[Offset];
- // We don't need to visit a module or any of its imports if we've already
- // deserialized the redecls from this module.
- return N != 0;
+ Result->FirstID != LocalID)
+ return None;
+ return Result->Offset;
}
- ModuleManager::DFSPreorderControl visitPreorder(ModuleFile &M) {
- for (unsigned I = 0, N = SearchDecls.size(); I != N; ++I) {
- if (needsToVisitImports(M, SearchDecls[I]))
- return ModuleManager::Continue;
+ bool visit(ModuleFile &M) {
+ llvm::ArrayRef<DeclID> ToSearch = SearchDecls;
+ GlobalDeclID LocalSearchDeclID = 0;
+
+ // First, check whether any of our search decls was declared in M.
+ auto I = std::lower_bound(SearchDecls.begin(), SearchDecls.end(),
+ M.BaseDeclID + NUM_PREDEF_DECL_IDS);
+ if (I != SearchDecls.end() && Reader.isDeclIDFromModule(*I, M)) {
+ LocalSearchDeclID = *I;
+ ToSearch = llvm::makeArrayRef(*I);
}
- return ModuleManager::SkipImports;
- }
- bool visitPostorder(ModuleFile &M) {
- // Visit each of the declarations.
- for (unsigned I = 0, N = SearchDecls.size(); I != N; ++I)
- searchForID(M, SearchDecls[I]);
- return false;
- }
-
- ArrayRef<Decl *> getChain() const {
- return Chain;
+ // Now, walk the search decls looking for one that's declared in this
+ // module file.
+ bool ImportedModulesMightHaveDecls = false;
+ for (auto GlobalID : ToSearch) {
+ // Map global ID of the first declaration down to the local ID
+ // used in this module file.
+ DeclID LocalID = Reader.mapGlobalIDToModuleFileGlobalID(M, GlobalID);
+ if (!LocalID)
+ continue;
+
+ auto MaybeOffset = findRedeclOffset(M, LocalID);
+ if (MaybeOffset) {
+ // We found it. Dig out all of the redeclarations.
+ unsigned Offset = *MaybeOffset;
+ unsigned N = M.RedeclarationChains[Offset];
+ if (!N)
+ // We've already loaded these.
+ // FIXME: In this case, we may be able to skip processing any
+ // imported modules too. We can't do that yet, though, because
+ // it's possible that our list of search decls misses out some
+ // search decls from modules that M imports.
+ continue;
+ M.RedeclarationChains[Offset++] = 0; // Don't try to deserialize again
+
+ // Note, declarations are listed from newest to oldest, which is the
+ // order that we want.
+ for (unsigned I = 0; I != N; ++I)
+ addToChain(Reader.GetLocalDecl(M, M.RedeclarationChains[Offset++]));
+ }
+
+ // We found a search decl that is not from this module, but was
+ // imported into this module, so some imported module has more decls
+ // of this entity.
+ if (!LocalSearchDeclID)
+ ImportedModulesMightHaveDecls = true;
+
+ // If we found redecls for some search decl, there are no redecls for
+ // any other search decl for the same chain in this module.
+ if (MaybeOffset)
+ break;
+ }
+
+ if (LocalSearchDeclID && LocalSearchDeclID != CanonID) {
+ // If the search decl was from this module, add it to the chain.
+ // Note, the chain is sorted from newest to oldest, so this goes last.
+ // We exclude the canonical declaration; it implicitly goes at the end.
+ addToChain(Reader.GetDecl(LocalSearchDeclID));
+ }
+
+ // Stop looking if we know that no imported module has any declarations.
+ return !ImportedModulesMightHaveDecls;
}
};
}
@@ -3531,15 +3538,15 @@ void ASTReader::loadPendingDeclChain(Dec
KeyDeclsMap::iterator KeyPos = KeyDecls.find(CanonDecl);
if (KeyPos != KeyDecls.end())
SearchDecls.append(KeyPos->second.begin(), KeyPos->second.end());
+ llvm::array_pod_sort(SearchDecls.begin(), SearchDecls.end());
// Build up the list of redeclarations.
RedeclChainVisitor Visitor(*this, SearchDecls, RedeclsDeserialized, CanonID);
- ModuleMgr.visitDepthFirst(&RedeclChainVisitor::visitPreorder,
- &RedeclChainVisitor::visitPostorder, &Visitor);
+ ModuleMgr.visit(&RedeclChainVisitor::visit, &Visitor);
// Retrieve the chains.
ArrayRef<Decl *> Chain = Visitor.getChain();
- if (Chain.empty() || (Chain.size() == 1 && Chain[0] == CanonDecl))
+ if (Chain.empty())
return;
// Hook up the chains.
@@ -3550,11 +3557,9 @@ void ASTReader::loadPendingDeclChain(Dec
if (!MostRecent)
MostRecent = CanonDecl;
for (unsigned I = 0, N = Chain.size(); I != N; ++I) {
- if (Chain[I] == CanonDecl)
- continue;
-
- ASTDeclReader::attachPreviousDecl(*this, Chain[I], MostRecent, CanonDecl);
- MostRecent = Chain[I];
+ auto *D = Chain[N - I - 1];
+ ASTDeclReader::attachPreviousDecl(*this, D, MostRecent, CanonDecl);
+ MostRecent = D;
}
ASTDeclReader::attachLatestDecl(CanonDecl, MostRecent);
}
Modified: cfe/trunk/lib/Serialization/ASTWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTWriter.cpp?rev=242253&r1=242252&r2=242253&view=diff
==============================================================================
--- cfe/trunk/lib/Serialization/ASTWriter.cpp (original)
+++ cfe/trunk/lib/Serialization/ASTWriter.cpp Tue Jul 14 19:02:40 2015
@@ -3791,7 +3791,8 @@ void ASTWriter::WriteRedeclarations() {
unsigned Size = 0;
LocalRedeclChains.push_back(0); // Placeholder for the size.
- // Collect the set of local redeclarations of this declaration.
+ // Collect the set of local redeclarations of this declaration, from newest
+ // to oldest.
for (const Decl *Prev = MostRecent; Prev;
Prev = Prev->getPreviousDecl()) {
if (!Prev->isFromASTFile() && Prev != Key) {
@@ -3802,10 +3803,6 @@ void ASTWriter::WriteRedeclarations() {
LocalRedeclChains[Offset] = Size;
- // Reverse the set of local redeclarations, so that we store them in
- // order (since we found them in reverse order).
- std::reverse(LocalRedeclChains.end() - Size, LocalRedeclChains.end());
-
// Add the mapping from the first ID from the AST to the set of local
// declarations.
LocalRedeclarationsInfo Info = { getDeclID(Key), Offset };
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