Module Debug Info: Emit namespaced C++ forward decls in the correct module.

The AST merges NamespaceDecls, but for module debug info it is
important to put a namespace decl (or rather its children) into the
correct (sub-)module, so we need to use the parent module of the decl
that triggered this namespace to be serialized as a second key when
looking up DINamespace nodes.

rdar://problem/29339538

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@302840 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 3e5434660567e9dc6c9dc8f8f0a5ab3b8c0836a2..d15ae06b455beceeb9259011ba4d9e08171704fa 100644 (file)
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -208,8 +208,10 @@ llvm::DIScope *CGDebugInfo::getContextDescriptor(const Decl *Context,
   }
 
   // Check namespace.
-  if (const auto *NSDecl = dyn_cast<NamespaceDecl>(Context))
-    return getOrCreateNameSpace(NSDecl);
+  if (const auto *NSDecl = dyn_cast<NamespaceDecl>(Context)) {
+    auto *ParentModule = dyn_cast<llvm::DIModule>(Default);
+    return getOrCreateNamespace(NSDecl, ParentModule);
+  }
 
   if (const auto *RDecl = dyn_cast<RecordDecl>(Context))
     if (!RDecl->isDependentType())
@@ -2861,7 +2863,7 @@ void CGDebugInfo::collectFunctionDeclProps(GlobalDecl GD, llvm::DIFile *Unit,
   if (DebugKind >= codegenoptions::LimitedDebugInfo) {
     if (const NamespaceDecl *NSDecl =
         dyn_cast_or_null<NamespaceDecl>(FD->getDeclContext()))
-      FDContext = getOrCreateNameSpace(NSDecl);
+    FDContext = getOrCreateNamespace(NSDecl, getParentModuleOrNull(FD));
     else if (const RecordDecl *RDecl =
              dyn_cast_or_null<RecordDecl>(FD->getDeclContext())) {
       llvm::DIScope *Mod = getParentModuleOrNull(RDecl);
@@ -3961,7 +3963,7 @@ void CGDebugInfo::EmitUsingDirective(const UsingDirectiveDecl &UD) {
       CGM.getCodeGenOpts().DebugExplicitImport) {
     DBuilder.createImportedModule(
         getCurrentContextDescriptor(cast<Decl>(UD.getDeclContext())),
-        getOrCreateNameSpace(NSDecl),
+        getOrCreateNamespace(NSDecl, getParentModuleOrNull(&UD)),
         getLineNumber(UD.getLocation()));
   }
 }
@@ -4021,23 +4023,32 @@ CGDebugInfo::EmitNamespaceAlias(const NamespaceAliasDecl &NA) {
   else
     R = DBuilder.createImportedDeclaration(
         getCurrentContextDescriptor(cast<Decl>(NA.getDeclContext())),
-        getOrCreateNameSpace(cast<NamespaceDecl>(NA.getAliasedNamespace())),
+        getOrCreateNamespace(cast<NamespaceDecl>(NA.getAliasedNamespace()),
+                             getParentModuleOrNull(&NA)),
         getLineNumber(NA.getLocation()), NA.getName());
   VH.reset(R);
   return R;
 }
 
 llvm::DINamespace *
-CGDebugInfo::getOrCreateNameSpace(const NamespaceDecl *NSDecl) {
+CGDebugInfo::getOrCreateNamespace(const NamespaceDecl *NSDecl,
+                                  llvm::DIModule *ParentModule) {
   NSDecl = NSDecl->getCanonicalDecl();
-  auto I = NameSpaceCache.find(NSDecl);
-  if (I != NameSpaceCache.end())
+  // The AST merges NamespaceDecls, but for module debug info it is important to
+  // put a namespace decl (or rather its children) into the correct
+  // (sub-)module, so use the parent module of the decl that triggered this
+  // namespace to be serialized as a second key.
+  NamespaceKey Key = {NSDecl, ParentModule};
+  auto I = NamespaceCache.find(Key);
+  if (I != NamespaceCache.end())
     return cast<llvm::DINamespace>(I->second);
 
   llvm::DIScope *Context = getDeclContextDescriptor(NSDecl);
-  llvm::DINamespace *NS =
-      DBuilder.createNameSpace(Context, NSDecl->getName(), NSDecl->isInline());
-  NameSpaceCache[NSDecl].reset(NS);
+  // Don't trust the context if it is a DIModule (see comment above).
+  llvm::DINamespace *NS = DBuilder.createNameSpace(
+      isa<llvm::DIModule>(Context) ? ParentModule : Context, NSDecl->getName(),
+      NSDecl->isInline());
+  NamespaceCache[Key].reset(NS);
   return NS;
 }
 

diff --git a/lib/CodeGen/CGDebugInfo.h b/lib/CodeGen/CGDebugInfo.h
index 5050ca0ad3fa0dcd16d21fd00f6321f91db06537..beafd25f9b19f568fc9536657feaf0801ab6d143 100644 (file)
--- a/lib/CodeGen/CGDebugInfo.h
+++ b/lib/CodeGen/CGDebugInfo.h
@@ -125,7 +125,8 @@ class CGDebugInfo {
   /// Cache declarations relevant to DW_TAG_imported_declarations (C++
   /// using declarations) that aren't covered by other more specific caches.
   llvm::DenseMap<const Decl *, llvm::TrackingMDRef> DeclCache;
-  llvm::DenseMap<const NamespaceDecl *, llvm::TrackingMDRef> NameSpaceCache;
+  typedef std::pair<const NamespaceDecl *, const llvm::DIModule *> NamespaceKey;
+  llvm::DenseMap<NamespaceKey, llvm::TrackingMDRef> NamespaceCache;
   llvm::DenseMap<const NamespaceAliasDecl *, llvm::TrackingMDRef>
       NamespaceAliasCache;
   llvm::DenseMap<const Decl *, llvm::TypedTrackingMDRef<llvm::DIDerivedType>>
@@ -194,8 +195,15 @@ class CGDebugInfo {
   getOrCreateFunctionType(const Decl *D, QualType FnType, llvm::DIFile *F);
   /// \return debug info descriptor for vtable.
   llvm::DIType *getOrCreateVTablePtrType(llvm::DIFile *F);
+
+  /// \return namespace descriptor for the given namespace decl.
+  ///
   /// \return namespace descriptor for the given namespace decl.
-  llvm::DINamespace *getOrCreateNameSpace(const NamespaceDecl *N);
+  /// \param ParentModule  The parent module (or nullptr) of this particular
+  ///                      namespace decl. This needs to be passed in because
+  ///                      the AST merges namespace decls.
+  llvm::DINamespace *getOrCreateNamespace(const NamespaceDecl *N,
+                                          llvm::DIModule *ParentModule);
   llvm::DIType *CreatePointerLikeType(llvm::dwarf::Tag Tag, const Type *Ty,
                                       QualType PointeeTy, llvm::DIFile *F);
   llvm::DIType *getOrCreateStructPtrType(StringRef Name, llvm::DIType *&Cache);

diff --git a/test/Modules/DebugInfoNamespace.cpp b/test/Modules/DebugInfoNamespace.cpp
new file mode 100644 (file)
index 0000000..33add08
--- /dev/null
+++ b/test/Modules/DebugInfoNamespace.cpp
@@ -0,0 +1,19 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -x objective-c++ -std=c++11 -debug-info-kind=standalone \
+// RUN:     -dwarf-ext-refs -fmodules \
+// RUN:     -fmodule-format=obj -fimplicit-module-maps \
+// RUN:     -triple %itanium_abi_triple -fmodules-cache-path=%t \
+// RUN:     %s -I %S/Inputs/DebugInfoNamespace -I %t -emit-llvm -o - \
+// RUN:     |  FileCheck %s
+
+#include "A.h"
+#include "B.h"
+using namespace N;
+B b;
+
+// Verify that the forward decl of B is in module B.
+//
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "B",
+// CHECK-SAME:             scope: ![[N:[0-9]+]]
+// CHECK: ![[N]] = !DINamespace(name: "N", scope: ![[B:[0-9]+]])
+// CHECK: ![[B]] = !DIModule(scope: null, name: "B",

diff --git a/test/Modules/Inputs/DebugInfoNamespace/A.h b/test/Modules/Inputs/DebugInfoNamespace/A.h
new file mode 100644 (file)
index 0000000..dc5a1cd
--- /dev/null
+++ b/test/Modules/Inputs/DebugInfoNamespace/A.h
@@ -0,0 +1,3 @@
+namespace N {
+  struct A {};
+}

diff --git a/test/Modules/Inputs/DebugInfoNamespace/B.h b/test/Modules/Inputs/DebugInfoNamespace/B.h
new file mode 100644 (file)
index 0000000..c9033a5
--- /dev/null
+++ b/test/Modules/Inputs/DebugInfoNamespace/B.h
@@ -0,0 +1,3 @@
+namespace N {
+  struct B {};
+}

diff --git a/test/Modules/Inputs/DebugInfoNamespace/module.modulemap b/test/Modules/Inputs/DebugInfoNamespace/module.modulemap
new file mode 100644 (file)
index 0000000..9300fcf
--- /dev/null
+++ b/test/Modules/Inputs/DebugInfoNamespace/module.modulemap
@@ -0,0 +1,8 @@
+module A {
+  header "A.h"
+  export *
+}
+module B {
+  header "B.h"
+  export *
+}