Warn about code that uses variables and functions with internal linkage
without defining them. This should be an error, but I'm paranoid about
"uses" that end up not actually requiring a definition. I'll revisit later.
Also, teach IR generation to not set internal linkage on variable
declarations, just for safety's sake. Doing so produces an invalid module
if the variable is not ultimately defined.
Also, fix several places in the test suite where we were using internal
functions without definitions.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126016 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index d5e9dbf..7d4b461 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -637,14 +637,26 @@
if (const CXXRecordDecl *record = dyn_cast<CXXRecordDecl>(this))
clearLinkageForClass(record);
- if (const ClassTemplateDecl *temp = dyn_cast<ClassTemplateDecl>(this)) {
+ if (ClassTemplateDecl *temp =
+ dyn_cast<ClassTemplateDecl>(const_cast<NamedDecl*>(this))) {
// Clear linkage for the template pattern.
CXXRecordDecl *record = temp->getTemplatedDecl();
record->HasCachedLinkage = 0;
clearLinkageForClass(record);
- // ...do we need to clear linkage for specializations, too?
+ // We need to clear linkage for specializations, too.
+ for (ClassTemplateDecl::spec_iterator
+ i = temp->spec_begin(), e = temp->spec_end(); i != e; ++i)
+ i->ClearLinkageCache();
}
+
+ // Clear cached linkage for function template decls, too.
+ if (FunctionTemplateDecl *temp =
+ dyn_cast<FunctionTemplateDecl>(const_cast<NamedDecl*>(this)))
+ for (FunctionTemplateDecl::spec_iterator
+ i = temp->spec_begin(), e = temp->spec_end(); i != e; ++i)
+ i->ClearLinkageCache();
+
}
Linkage NamedDecl::getLinkage() const {
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 5a45df2..9e5d7cf 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -983,7 +983,7 @@
// Set linkage and visibility in case we never see a definition.
NamedDecl::LinkageInfo LV = D->getLinkageAndVisibility();
if (LV.linkage() != ExternalLinkage) {
- GV->setLinkage(llvm::GlobalValue::InternalLinkage);
+ // Don't set internal linkage on declarations.
} else {
if (D->hasAttr<DLLImportAttr>())
GV->setLinkage(llvm::GlobalValue::DLLImportLinkage);
diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index 7eb1c57..23a3c24 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -271,6 +271,65 @@
return false;
}
+namespace {
+ struct UndefinedInternal {
+ NamedDecl *decl;
+ FullSourceLoc useLoc;
+
+ UndefinedInternal(NamedDecl *decl, FullSourceLoc useLoc)
+ : decl(decl), useLoc(useLoc) {}
+ };
+
+ bool operator<(const UndefinedInternal &l, const UndefinedInternal &r) {
+ return l.useLoc.isBeforeInTranslationUnitThan(r.useLoc);
+ }
+}
+
+/// checkUndefinedInternals - Check for undefined objects with internal linkage.
+static void checkUndefinedInternals(Sema &S) {
+ if (S.UndefinedInternals.empty()) return;
+
+ // Collect all the still-undefined entities with internal linkage.
+ llvm::SmallVector<UndefinedInternal, 16> undefined;
+ for (llvm::DenseMap<NamedDecl*,SourceLocation>::iterator
+ i = S.UndefinedInternals.begin(), e = S.UndefinedInternals.end();
+ i != e; ++i) {
+ NamedDecl *decl = i->first;
+
+ // Ignore attributes that have become invalid.
+ if (decl->isInvalidDecl()) continue;
+
+ // __attribute__((weakref)) is basically a definition.
+ if (decl->hasAttr<WeakRefAttr>()) continue;
+
+ if (FunctionDecl *fn = dyn_cast<FunctionDecl>(decl)) {
+ if (fn->isPure() || fn->hasBody())
+ continue;
+ } else {
+ if (cast<VarDecl>(decl)->hasDefinition() != VarDecl::DeclarationOnly)
+ continue;
+ }
+
+ // We build a FullSourceLoc so that we can sort with array_pod_sort.
+ FullSourceLoc loc(i->second, S.Context.getSourceManager());
+ undefined.push_back(UndefinedInternal(decl, loc));
+ }
+
+ if (undefined.empty()) return;
+
+ // Sort (in order of use site) so that we're not (as) dependent on
+ // the iteration order through an llvm::DenseMap.
+ llvm::array_pod_sort(undefined.begin(), undefined.end());
+
+ for (llvm::SmallVectorImpl<UndefinedInternal>::iterator
+ i = undefined.begin(), e = undefined.end(); i != e; ++i) {
+ NamedDecl *decl = i->decl;
+ S.Diag(decl->getLocation(), diag::warn_undefined_internal)
+ << isa<VarDecl>(decl) << decl;
+ S.Diag(i->useLoc, diag::note_used_here);
+ }
+}
+
/// ActOnEndOfTranslationUnit - This is called at the very end of the
/// translation unit when EOF is reached and all but the top-level scope is
/// popped.
@@ -403,6 +462,8 @@
<< DiagD->getDeclName();
}
}
+
+ checkUndefinedInternals(*this);
}
TUScope = 0;
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 792eb8a..df49ad5 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -9284,6 +9284,9 @@
MarkVTableUsed(Loc, MethodDecl->getParent());
}
if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) {
+ // Recursive functions should be marked when used from another function.
+ if (CurContext == Function) return;
+
// Implicit instantiation of function templates and member functions of
// class templates.
if (Function->isImplicitlyInstantiable()) {
@@ -9312,19 +9315,23 @@
else
PendingInstantiations.push_back(std::make_pair(Function, Loc));
}
- } else // Walk redefinitions, as some of them may be instantiable.
+ } else {
+ // Walk redefinitions, as some of them may be instantiable.
for (FunctionDecl::redecl_iterator i(Function->redecls_begin()),
e(Function->redecls_end()); i != e; ++i) {
if (!i->isUsed(false) && i->isImplicitlyInstantiable())
MarkDeclarationReferenced(Loc, *i);
}
+ }
- // FIXME: keep track of references to static functions
+ // Keep track of used but undefined functions.
+ if (!Function->isPure() && !Function->hasBody() &&
+ Function->getLinkage() != ExternalLinkage) {
+ SourceLocation &old = UndefinedInternals[Function->getCanonicalDecl()];
+ if (old.isInvalid()) old = Loc;
+ }
- // Recursive functions should be marked when used from another function.
- if (CurContext != Function)
- Function->setUsed(true);
-
+ Function->setUsed(true);
return;
}
@@ -9341,7 +9348,12 @@
}
}
- // FIXME: keep track of references to static data?
+ // Keep track of used but undefined variables.
+ if (Var->hasDefinition() == VarDecl::DeclarationOnly
+ && Var->getLinkage() != ExternalLinkage) {
+ SourceLocation &old = UndefinedInternals[Var->getCanonicalDecl()];
+ if (old.isInvalid()) old = Loc;
+ }
D->setUsed(true);
return;