Basic ODR checking for C++ modules:
If we have multiple definitions of the same entity from different modules, we
nominate the first definition which we see as being the canonical definition.
If we load a declaration from a different definition and we can't find a
corresponding declaration in the canonical definition, issue a diagnostic.
This is insufficient to prevent things from going horribly wrong in all cases
-- we might be in the middle of emitting IR for a function when we trigger some
deserialization and discover that it refers to an incoherent piece of the AST,
by which point it's probably too late to bail out -- but we'll at least produce
a diagnostic.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@192950 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 9bb9a7a..bafe74b 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -7337,7 +7337,8 @@
void ASTReader::finishPendingActions() {
while (!PendingIdentifierInfos.empty() || !PendingDeclChains.empty() ||
- !PendingMacroIDs.empty() || !PendingDeclContextInfos.empty()) {
+ !PendingMacroIDs.empty() || !PendingDeclContextInfos.empty() ||
+ !PendingOdrMergeChecks.empty()) {
// If any identifiers with corresponding top-level declarations have
// been loaded, load those declarations now.
typedef llvm::DenseMap<IdentifierInfo *, SmallVector<Decl *, 2> >
@@ -7400,6 +7401,64 @@
DeclContext *LexicalDC = cast<DeclContext>(GetDecl(Info.LexicalDC));
Info.D->setDeclContextsImpl(SemaDC, LexicalDC, getContext());
}
+
+ // For each declaration from a merged context, check that the canonical
+ // definition of that context also contains a declaration of the same
+ // entity.
+ while (!PendingOdrMergeChecks.empty()) {
+ NamedDecl *D = PendingOdrMergeChecks.pop_back_val();
+
+ // FIXME: Skip over implicit declarations for now. This matters for things
+ // like implicitly-declared special member functions. This isn't entirely
+ // correct; we can end up with multiple unmerged declarations of the same
+ // implicit entity.
+ if (D->isImplicit())
+ continue;
+
+ DeclContext *CanonDef = D->getDeclContext();
+ DeclContext::lookup_result R = CanonDef->lookup(D->getDeclName());
+
+ bool Found = false;
+ const Decl *DCanon = D->getCanonicalDecl();
+
+ llvm::SmallVector<const NamedDecl*, 4> Candidates;
+ for (DeclContext::lookup_iterator I = R.begin(), E = R.end();
+ !Found && I != E; ++I) {
+ for (Decl::redecl_iterator RI = (*I)->redecls_begin(),
+ RE = (*I)->redecls_end();
+ RI != RE; ++RI) {
+ if ((*RI)->getLexicalDeclContext() == CanonDef) {
+ // This declaration is present in the canonical definition. If it's
+ // in the same redecl chain, it's the one we're looking for.
+ if ((*RI)->getCanonicalDecl() == DCanon)
+ Found = true;
+ else
+ Candidates.push_back(cast<NamedDecl>(*RI));
+ break;
+ }
+ }
+ }
+
+ if (!Found) {
+ D->setInvalidDecl();
+
+ Module *CanonDefModule = cast<Decl>(CanonDef)->getOwningModule();
+ Diag(D->getLocation(), diag::err_module_odr_violation_missing_decl)
+ << D << D->getOwningModule()->getFullModuleName()
+ << CanonDef << !CanonDefModule
+ << (CanonDefModule ? CanonDefModule->getFullModuleName() : "");
+
+ if (Candidates.empty())
+ Diag(cast<Decl>(CanonDef)->getLocation(),
+ diag::note_module_odr_violation_no_possible_decls) << D;
+ else {
+ for (unsigned I = 0, N = Candidates.size(); I != N; ++I)
+ Diag(Candidates[I]->getLocation(),
+ diag::note_module_odr_violation_possible_decl)
+ << Candidates[I];
+ }
+ }
+ }
}
// If we deserialized any C++ or Objective-C class definitions, any
diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index 14379f3..e68c7fc 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -2193,6 +2193,9 @@
return Result;
}
+ // FIXME: Bail out for non-canonical declarations. We will have performed any
+ // necessary merging already.
+
DeclContext *DC = D->getDeclContext()->getRedeclContext();
if (DC->isTranslationUnit() && Reader.SemaObj) {
IdentifierResolver &IdResolver = Reader.SemaObj->IdResolver;
@@ -2226,17 +2229,23 @@
if (isSameEntity(*I, D))
return FindExistingResult(Reader, D, *I);
}
- return FindExistingResult(Reader, D, /*Existing=*/0);
} else if (DeclContext *MergeDC = getPrimaryContextForMerging(DC)) {
DeclContext::lookup_result R = MergeDC->noload_lookup(Name);
for (DeclContext::lookup_iterator I = R.begin(), E = R.end(); I != E; ++I) {
if (isSameEntity(*I, D))
return FindExistingResult(Reader, D, *I);
}
- return FindExistingResult(Reader, D, /*Existing=*/0);
+ } else {
+ // Not in a mergeable context.
+ return FindExistingResult(Reader);
}
- return FindExistingResult(Reader);
+ // If this declaration is from a merged context, make a note that we need to
+ // check that the canonical definition of that context contains the decl.
+ if (Reader.MergedDeclContexts.count(D->getLexicalDeclContext()))
+ Reader.PendingOdrMergeChecks.push_back(D);
+
+ return FindExistingResult(Reader, D, /*Existing=*/0);
}
void ASTDeclReader::attachPreviousDecl(Decl *D, Decl *previous) {