Revert "Revert "PR14606: debug info imported_module support""

This reverts commit r179840 with a fix to test/DebugInfo/two-cus-from-same-file.ll

I'm not sure why that test only failed on ARM & MIPS and not X86 Linux, even
though the debug info was clearly invalid on all of them, but this ought to fix
it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179996 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 73 insertions, 6 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 762c475c8e..c3f475178b 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -763,6 +763,23 @@ void DwarfDebug::constructSubprogramDIE(CompileUnit *TheCU,
     TheCU->addGlobalName(SP.getName(), SubprogramDie);
 }
 
+void DwarfDebug::constructImportedModuleDIE(CompileUnit *TheCU,
+                                            const MDNode *N) {
+  DIImportedModule Module(N);
+  if (!Module.Verify())
+    return;
+  DIE *IMDie = new DIE(dwarf::DW_TAG_imported_module);
+  TheCU->insertDIE(Module, IMDie);
+  DIE *NSDie = TheCU->getOrCreateNameSpace(Module.getNameSpace());
+  unsigned FileID = getOrCreateSourceID(Module.getContext().getFilename(),
+                                        Module.getContext().getDirectory(),
+                                        TheCU->getUniqueID());
+  TheCU->addUInt(IMDie, dwarf::DW_AT_decl_file, 0, FileID);
+  TheCU->addUInt(IMDie, dwarf::DW_AT_decl_line, 0, Module.getLineNumber());
+  TheCU->addDIEEntry(IMDie, dwarf::DW_AT_import, dwarf::DW_FORM_ref4, NSDie);
+  TheCU->addToContextOwner(IMDie, Module.getContext());
+}
+
 // Emit all Dwarf sections that should come prior to the content. Create
 // global DIEs and emit initial debug info sections. This is invoked by
 // the target AsmPrinter.
@@ -796,6 +813,11 @@ void DwarfDebug::beginModule() {
     DIArray RetainedTypes = CUNode.getRetainedTypes();
     for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i)
       CU->getOrCreateTypeDIE(RetainedTypes.getElement(i));
+    // Emit imported_modules last so that the relevant context is already
+    // available.
+    DIArray ImportedModules = CUNode.getImportedModules();
+    for (unsigned i = 0, e = ImportedModules.getNumElements(); i != e; ++i)
+      constructImportedModuleDIE(CU, ImportedModules.getElement(i));
     // If we're splitting the dwarf out now that we've got the entire
     // CU then construct a skeleton CU based upon it.
     if (useSplitDwarf()) {
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 9a38256d8e..1eb7e3ecea 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -555,6 +555,9 @@ private:
   /// \brief Construct subprogram DIE.
   void constructSubprogramDIE(CompileUnit *TheCU, const MDNode *N);
 
+  /// \brief Construct import_module DIE.
+  void constructImportedModuleDIE(CompileUnit *TheCU, const MDNode *N);
+
   /// \brief Register a source line with debug info. Returns the unique
   /// label that was emitted and which provides correspondence to the
   /// source line list.
diff --git a/lib/IR/DIBuilder.cpp b/lib/IR/DIBuilder.cpp
index ed9f98f514..0980e80aa4 100644
--- a/lib/IR/DIBuilder.cpp
+++ b/lib/IR/DIBuilder.cpp
@@ -61,6 +61,9 @@ void DIBuilder::finalize() {
 
   DIArray GVs = getOrCreateArray(AllGVs);
   DIType(TempGVs).replaceAllUsesWith(GVs);
+
+  DIArray IMs = getOrCreateArray(AllImportedModules);
+  DIType(TempImportedModules).replaceAllUsesWith(IMs);
 }
 
 /// getNonCompileUnitScope - If N is compile unit return NULL otherwise return
@@ -101,6 +104,8 @@ void DIBuilder::createCompileUnit(unsigned Lang, StringRef Filename,
 
   TempGVs = MDNode::getTemporary(VMContext, TElts);
 
+  TempImportedModules = MDNode::getTemporary(VMContext, TElts);
+
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_compile_unit),
     createFilePathPair(VMContext, Filename, Directory),
@@ -113,6 +118,7 @@ void DIBuilder::createCompileUnit(unsigned Lang, StringRef Filename,
     TempRetainTypes,
     TempSubprograms,
     TempGVs,
+    TempImportedModules,
     MDString::get(VMContext, SplitName)
   };
   TheCU = DICompileUnit(MDNode::get(VMContext, Elts));
@@ -122,6 +128,21 @@ void DIBuilder::createCompileUnit(unsigned Lang, StringRef Filename,
   NMD->addOperand(TheCU);
 }
 
+DIImportedModule DIBuilder::createImportedModule(DIScope Context,
+                                                 DINameSpace NS,
+                                                 unsigned Line) {
+  Value *Elts[] = {
+    GetTagConstant(VMContext, dwarf::DW_TAG_imported_module),
+    Context,
+    NS,
+    ConstantInt::get(Type::getInt32Ty(VMContext), Line),
+  };
+  DIImportedModule M(MDNode::get(VMContext, Elts));
+  assert(M.Verify() && "Imported module should be valid");
+  AllImportedModules.push_back(M);
+  return M;
+}
+
 /// createFile - Create a file descriptor to hold debugging information
 /// for a file.
 DIFile DIBuilder::createFile(StringRef Filename, StringRef Directory) {
diff --git a/lib/IR/DebugInfo.cpp b/lib/IR/DebugInfo.cpp
index 10beb69824..ec83dcaf52 100644
--- a/lib/IR/DebugInfo.cpp
+++ b/lib/IR/DebugInfo.cpp
@@ -64,7 +64,8 @@ bool DIDescriptor::Verify() const {
           DISubrange(DbgNode).Verify() || DIEnumerator(DbgNode).Verify() ||
           DIObjCProperty(DbgNode).Verify() ||
           DITemplateTypeParameter(DbgNode).Verify() ||
-          DITemplateValueParameter(DbgNode).Verify());
+          DITemplateValueParameter(DbgNode).Verify() ||
+          DIImportedModule(DbgNode).Verify());
 }
 
 static Value *getField(const MDNode *DbgNode, unsigned Elt) {
@@ -336,6 +337,12 @@ bool DIDescriptor::isEnumerator() const {
 bool DIDescriptor::isObjCProperty() const {
   return DbgNode && getTag() == dwarf::DW_TAG_APPLE_property;
 }
+
+/// \brief Return true if the specified tag is DW_TAG_imported_module.
+bool DIDescriptor::isImportedModule() const {
+  return DbgNode && getTag() == dwarf::DW_TAG_imported_module;
+}
+
 //===----------------------------------------------------------------------===//
 // Simple Descriptor Constructors and other Methods
 //===----------------------------------------------------------------------===//
@@ -418,7 +425,7 @@ bool DICompileUnit::Verify() const {
   if (N.empty())
     return false;
   // It is possible that directory and produce string is empty.
-  return DbgNode->getNumOperands() == 12;
+  return DbgNode->getNumOperands() == 13;
 }
 
 /// Verify - Verify that an ObjC property is well formed.
@@ -580,6 +587,11 @@ bool DITemplateValueParameter::Verify() const {
   return isTemplateValueParameter() && DbgNode->getNumOperands() == 8;
 }
 
+/// \brief Verify that the imported module descriptor is well formed.
+bool DIImportedModule::Verify() const {
+  return isImportedModule() && DbgNode->getNumOperands() == 4;
+}
+
 /// getOriginalTypeSize - If this type is derived from a base type then
 /// return base type size.
 uint64_t DIDerivedType::getOriginalTypeSize() const {
@@ -694,7 +706,7 @@ StringRef DIScope::getDirectory() const {
 }
 
 DIArray DICompileUnit::getEnumTypes() const {
-  if (!DbgNode || DbgNode->getNumOperands() < 12)
+  if (!DbgNode || DbgNode->getNumOperands() < 13)
     return DIArray();
 
   if (MDNode *N = dyn_cast_or_null<MDNode>(DbgNode->getOperand(7)))
@@ -703,7 +715,7 @@ DIArray DICompileUnit::getEnumTypes() const {
 }
 
 DIArray DICompileUnit::getRetainedTypes() const {
-  if (!DbgNode || DbgNode->getNumOperands() < 12)
+  if (!DbgNode || DbgNode->getNumOperands() < 13)
     return DIArray();
 
   if (MDNode *N = dyn_cast_or_null<MDNode>(DbgNode->getOperand(8)))
@@ -712,7 +724,7 @@ DIArray DICompileUnit::getRetainedTypes() const {
 }
 
 DIArray DICompileUnit::getSubprograms() const {
-  if (!DbgNode || DbgNode->getNumOperands() < 12)
+  if (!DbgNode || DbgNode->getNumOperands() < 13)
     return DIArray();
 
   if (MDNode *N = dyn_cast_or_null<MDNode>(DbgNode->getOperand(9)))
@@ -722,7 +734,7 @@ DIArray DICompileUnit::getSubprograms() const {
 
 
 DIArray DICompileUnit::getGlobalVariables() const {
-  if (!DbgNode || DbgNode->getNumOperands() < 12)
+  if (!DbgNode || DbgNode->getNumOperands() < 13)
     return DIArray();
 
   if (MDNode *N = dyn_cast_or_null<MDNode>(DbgNode->getOperand(10)))
@@ -730,6 +742,15 @@ DIArray DICompileUnit::getGlobalVariables() const {
   return DIArray();
 }
 
+DIArray DICompileUnit::getImportedModules() const {
+  if (!DbgNode || DbgNode->getNumOperands() < 13)
+    return DIArray();
+
+  if (MDNode *N = dyn_cast_or_null<MDNode>(DbgNode->getOperand(11)))
+    return DIArray(N);
+  return DIArray();
+}
+
 /// fixupObjcLikeName - Replace contains special characters used
 /// in a typical Objective-C names with '.' in a given string.
 static void fixupObjcLikeName(StringRef Str, SmallVectorImpl<char> &Out) {