Debug info: Represent clang-imported submodules.

Previously an import of a submodule would emit debug info for
importing the root module.

<rdar://problem/17260802>

Author: adrian-prantl

lib/IRGen/IRGenDebugInfo.cpp

@@ -34,11 +34,14 @@
 #include "swift/SIL/SILDebugScope.h"
 #include "swift/SIL/SILModule.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/ExternalASTSource.h"
 #include "clang/AST/Decl.h"
 #include "clang/Basic/Module.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Serialization/ASTReader.h"
 #include "llvm/Config/config.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/Module.h"
@@ -190,7 +193,7 @@ SILLocation::DebugLoc getDeserializedLoc(Decl *D) {
 /// Use the SM to figure out the actual line/column of a SourceLoc.
 template <typename WithLoc>
 SILLocation::DebugLoc getDebugLoc(IRGenDebugInfo &DI, WithLoc *S,
-                                  bool End = false) {
+                                  bool End = false) {  
   SILLocation::DebugLoc L;
   if (S == nullptr)
     return L;
@@ -814,6 +817,23 @@ llvm::DIModule *IRGenDebugInfo::getOrCreateModule(StringRef Key,
   return M;
 }
 
+llvm::DIModule *IRGenDebugInfo::getOrCreateModule(
+    clang::ExternalASTSource::ASTSourceDescriptor Desc) {
+  // Handle Clang modules.
+  if (const clang::Module *ClangModule = Desc.getModuleOrNull()) {
+    llvm::DIModule *Parent = nullptr;
+    if (ClangModule->Parent) {
+      clang::ExternalASTSource::ASTSourceDescriptor PM(*ClangModule->Parent);
+      Parent = getOrCreateModule(PM);
+    }
+    return getOrCreateModule(ClangModule->getFullModuleName(), Parent,
+                             Desc.getModuleName(), Desc.getPath());
+  }
+  // Handle PCH.
+  return getOrCreateModule(Desc.getASTFile(), nullptr, Desc.getModuleName(),
+                           Desc.getPath());
+};
+
 llvm::DISubprogram *IRGenDebugInfo::emitFunction(SILFunction &SILFn,
                                                  llvm::Function *Fn) {
   auto *DS = SILFn.getDebugScope();
@@ -1491,6 +1511,13 @@ llvm::DIType *IRGenDebugInfo::createType(DebugTypeInfo DbgTy,
     auto *StructTy = BaseTy->castTo<StructType>();
     auto *Decl = StructTy->getDecl();
     auto L = getDebugLoc(*this, Decl);
+    if (auto *ClangDecl = Decl->getClangDecl()) {
+      auto ClangSrcLoc = ClangDecl->getLocStart();
+      clang::SourceManager &ClangSM =
+          CI.getClangASTContext().getSourceManager();
+      L.Line = ClangSM.getPresumedLineNumber(ClangSrcLoc);
+      L.Filename = ClangSM.getBufferName(ClangSrcLoc);
+    }
     auto *File = getOrCreateFile(L.Filename);
     if (Opts.DebugInfoKind > IRGenDebugInfoKind::ASTTypes)
       return createStructType(DbgTy, Decl, StructTy, Scope, File, L.Line,
@@ -1515,28 +1542,6 @@ llvm::DIType *IRGenDebugInfo::createType(DebugTypeInfo DbgTy,
           CI.getClangASTContext().getSourceManager();
       L.Line = ClangSM.getPresumedLineNumber(ClangSrcLoc);
       L.Filename = ClangSM.getBufferName(ClangSrcLoc);
-
-      // Use "__ObjC" as default for implicit decls.
-      // FIXME: Do something more clever based on the decl's mangled name.
-      std::string FullModuleNameBuffer;
-      StringRef ModulePath;
-      StringRef ModuleName = "__ObjC";
-      if (auto *OwningModule = ClangDecl->getImportedOwningModule())
-        ModuleName = OwningModule->getTopLevelModuleName();
-
-      if (auto *SwiftModule = Decl->getParentModule())
-        if (auto *ClangModule = SwiftModule->findUnderlyingClangModule()) {
-          // FIXME: Clang submodules are not handled here.
-          // FIXME: Clang module config macros are not handled here.
-          FullModuleNameBuffer = ClangModule->getFullModuleName();
-          ModuleName = FullModuleNameBuffer;
-          // FIXME: A clang module's Directory is supposed to be the
-          // directory containing the module map, but ClangImporter
-          // sets it to the module cache directory.
-          if (ClangModule->Directory)
-            ModulePath = ClangModule->Directory->getName();
-        }
-      Scope = getOrCreateModule(ModuleName, TheCU, ModuleName, ModulePath);
     }
     assert(SizeInBits == CI.getTargetInfo().getPointerWidth(0));
     return createPointerSizedStruct(Scope, Decl->getNameStr(),
@@ -1856,10 +1861,20 @@ llvm::DIType *IRGenDebugInfo::getOrCreateType(DebugTypeInfo DbgTy) {
   //
   // FIXME: Builtin and qualified types in LLVM have no parent
   // scope. TODO: This can be fixed by extending DIBuilder.
+  llvm::DIScope *Scope = nullptr;
   DeclContext *Context = DbgTy.getType()->getNominalOrBoundGenericNominal();
-  if (Context)
+  if (Context) {
+    if (auto *D = Context->getAsNominalTypeOrNominalTypeExtensionContext())
+      if (auto *ClangDecl = D->getClangDecl()) {
+        clang::ASTReader &Reader = *CI.getClangInstance().getModuleManager();
+        auto Idx = ClangDecl->getOwningModuleID();
+        if (auto Info = Reader.getSourceDescriptor(Idx))
+          Scope = getOrCreateModule(*Info);
+      }
     Context = Context->getParent();
-  llvm::DIScope *Scope = getOrCreateContext(Context);
+  }
+  if (!Scope)
+    Scope = getOrCreateContext(Context);
   llvm::DIType *DITy = createType(DbgTy, MangledName, Scope, getFile(Scope));
 
   // Incrementally build the DIRefMap.

lib/IRGen/IRGenDebugInfo.h

@@ -21,6 +21,7 @@
 #include "IRBuilder.h"
 #include "IRGenFunction.h"
 #include "IRGenModule.h"
+#include "clang/AST/ExternalASTSource.h"
 #include "swift/SIL/SILLocation.h"
 #include "llvm/IR/DIBuilder.h"
 #include "llvm/Support/Allocator.h"
@@ -296,6 +297,9 @@ class IRGenDebugInfo {
   /// Return a cached module for an access path or create a new one.
   llvm::DIModule *getOrCreateModule(StringRef Key, llvm::DIScope *Parent,
                                     StringRef Name, StringRef IncludePath);
+  llvm::DIModule *
+  getOrCreateModule(clang::ExternalASTSource::ASTSourceDescriptor M);
+
   llvm::DIScope *getModule(StringRef MangledName);
   /// Return an array with the DITypes for each of a struct's elements.
   llvm::DINodeArray getStructMembers(NominalTypeDecl *D, Type BaseTy,

lib/IRGen/IRGenModule.cpp

@@ -97,8 +97,8 @@ static clang::CodeGenerator *createClangCodeGenerator(ASTContext &Context,
     CGO.setDebugInfo(clang::codegenoptions::DebugInfoKind::DebugLineTablesOnly);
     break;
   case IRGenDebugInfoKind::ASTTypes:
-    // TODO: Enable -gmodules for the clang code generator.
   case IRGenDebugInfoKind::DwarfTypes:
+    CGO.DebugTypeExtRefs = true;
     CGO.setDebugInfo(clang::codegenoptions::DebugInfoKind::FullDebugInfo);
     break;
   }

test/DebugInfo/ImportClangSubmodule.swift

@@ -1,13 +1,12 @@
-// RUN: rm -rf %t && mkdir -p %t
-// REQUIRES: OS=macosx
+// RUN: %target-swift-frontend -emit-ir %s -g -I %S/Inputs -o - | %FileCheck %s
 
-// RUN: %target-swift-frontend -emit-ir %s -g -o - | %FileCheck %s
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "Bar",
+// CHECK-SAME:             scope: ![[SUBMODULE:[0-9]+]]
 
-// CHECK: !DIImportedEntity(
-// CHECK: tag: DW_TAG_imported_module{{.*}}entity: ![[C:.*]], line: [[@LINE+1]])
-import Darwin.C
+// CHECK: ![[SUBMODULE]] = !DIModule(scope: ![[CLANGMODULE:[0-9]+]],
+// CHECK-SAME:                       name: "SubModule",
+// CHECK: ![[CLANGMODULE]] = !DIModule(scope: null, name: "ClangModule",
+// CHECK: !DIImportedEntity({{.*}}, entity: ![[SUBMODULE]], line: [[@LINE+1]])
+import ClangModule.SubModule
 
-let irrational = sqrt(2 as Double)
-
-// CHECK: ![[C]] = !DIModule(scope: ![[Darwin:.*]], name: "C",
-// CHECK: ![[Darwin]] = !DIModule(scope: null, name: "Darwin",
+let bar = Bar()

test/DebugInfo/Inputs/SubModule.h

@@ -0,0 +1 @@
+struct Bar {};

test/DebugInfo/Inputs/module.modulemap

@@ -1,3 +1,8 @@
 module ClangModule {
   header "ClangModule.h"
+  export *
+  module SubModule {
+    header "SubModule.h"
+    export *
+  }
 }

test/DebugInfo/test-foundation.swift

@@ -18,8 +18,9 @@ class MyObject : NSObject {
   var MyArr = NSArray()
 // IMPORT-CHECK: filename: "test-foundation.swift"
 // IMPORT-CHECK-DAG: [[FOUNDATION:[0-9]+]] = !DIModule({{.*}} name: "Foundation",{{.*}} includePath:
-// IMPORT-CHECK-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "NSArray", scope: ![[FOUNDATION]]
-// IMPORT-CHECK-DAG: !DIImportedEntity(tag: DW_TAG_imported_module, {{.*}}entity: ![[FOUNDATION]]
+  // IMPORT-CHECK-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "NSArray", scope: ![[NSARRAY:[0-9]+]]
+  //  IMPORT-CHECK-DAG: ![[NSARRAY]] = !DIModule(scope: ![[FOUNDATION:[0-9]+]], name: "NSArray"
+  // IMPORT-CHECK-DAG: !DIImportedEntity(tag: DW_TAG_imported_module, {{.*}}entity: ![[FOUNDATION]]
 
   func foo(_ obj: MyObject) {
     return obj.foo(obj)