The debugger sometimes lookup dynamically in the runtime to find ivar info of any Objective-C classes. It would be very helpful to debugger if the compiler encodes runtime version number in DWARF.

Add support for two additional DWARF attributes to encode Objective-C runtime version number.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64834 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Devang Patel

include/llvm/Analysis/DebugInfo.h

@@ -118,9 +118,11 @@ namespace llvm {
     /// code generator accepts maximum one main compile unit per module. If a
     /// module does not contain any main compile unit then the code generator 
     /// will emit multiple compile units in the output object file.
+
     bool isMain() const                { return getUnsignedField(6); }
     bool isOptimized() const           { return getUnsignedField(7); }
     std::string getFlags() const       { return getStringField(8); }
+    unsigned getRunTimeVersion() const { return getUnsignedField(9); }
 
     /// Verify - Verify that a compile unit is well formed.
     bool Verify() const;
@@ -231,6 +233,7 @@ namespace llvm {
   public:
     explicit DICompositeType(GlobalVariable *GV);
     DIArray getTypeArray() const { return getFieldAs<DIArray>(10); }
+    unsigned getRunTimeLang() const { return getUnsignedField(11); }
 
     /// Verify - Verify that a composite type descriptor is well formed.
     bool Verify() const;
@@ -381,7 +384,8 @@ namespace llvm {
                                     const std::string &Producer,
                                     bool isMain = false,
                                     bool isOptimized = false,
-                                    const char *Flags = "");
+                                    const char *Flags = "",
+                                    unsigned RunTimeVer = 0);
 
     /// CreateEnumerator - Create a single enumerator value.
     DIEnumerator CreateEnumerator(const std::string &Name, uint64_t Val);
@@ -412,7 +416,8 @@ namespace llvm {
                                         uint64_t AlignInBits,
                                         uint64_t OffsetInBits, unsigned Flags,
                                         DIType DerivedFrom,
-                                        DIArray Elements);
+                                        DIArray Elements,
+                                        unsigned RunTimeLang = 0);
 
     /// CreateSubprogram - Create a new descriptor for the specified subprogram.
     /// See comments in DISubprogram for descriptions of these fields.

include/llvm/Support/Dwarf.h

@@ -225,6 +225,8 @@ enum dwarf_constants {
   // Apple extensions.
   DW_AT_APPLE_optimized = 0x3fe1,
   DW_AT_APPLE_flags = 0x3fe2,
+  DW_AT_APPLE_major_runtime_vers = 0x3fe5,
+  DW_AT_APPLE_runtime_class = 0x3fe6,
 
   // Attribute form encodings
   DW_FORM_addr = 0x01,

lib/Analysis/DebugInfo.cpp

@@ -453,7 +453,8 @@ DICompileUnit DIFactory::CreateCompileUnit(unsigned LangID,
                                            const std::string &Producer,
                                            bool isMain,
                                            bool isOptimized,
-                                           const char *Flags) {
+                                           const char *Flags,
+                                           unsigned RunTimeVer) {
   Constant *Elts[] = {
     GetTagConstant(dwarf::DW_TAG_compile_unit),
     getCastToEmpty(GetOrCreateCompileUnitAnchor()),
@@ -463,7 +464,8 @@ DICompileUnit DIFactory::CreateCompileUnit(unsigned LangID,
     GetStringConstant(Producer),
     ConstantInt::get(Type::Int1Ty, isMain),
     ConstantInt::get(Type::Int1Ty, isOptimized),
-    GetStringConstant(Flags)
+    GetStringConstant(Flags),
+    ConstantInt::get(Type::Int32Ty, RunTimeVer)
   };
 
   Constant *Init = ConstantStruct::get(Elts, sizeof(Elts)/sizeof(Elts[0]));
@@ -573,7 +575,8 @@ DICompositeType DIFactory::CreateCompositeType(unsigned Tag,
                                                uint64_t OffsetInBits,
                                                unsigned Flags,
                                                DIType DerivedFrom,
-                                               DIArray Elements) {
+                                               DIArray Elements,
+                                               unsigned RuntimeLang) {
 
   Constant *Elts[] = {
     GetTagConstant(Tag),
@@ -586,7 +589,8 @@ DICompositeType DIFactory::CreateCompositeType(unsigned Tag,
     ConstantInt::get(Type::Int64Ty, OffsetInBits),
     ConstantInt::get(Type::Int32Ty, Flags),
     getCastToEmpty(DerivedFrom),
-    getCastToEmpty(Elements)
+    getCastToEmpty(Elements),
+    ConstantInt::get(Type::Int32Ty, RuntimeLang)
   };
 
   Constant *Init = ConstantStruct::get(Elts, sizeof(Elts)/sizeof(Elts[0]));

lib/CodeGen/AsmPrinter/DwarfWriter.cpp

@@ -1770,6 +1770,9 @@ class DwarfDebug : public Dwarf {
                                       DIDerivedType(Element.getGV()));
           Buffer.AddChild(ElemDie);
         }
+        unsigned RLang = CTy.getRunTimeLang();
+        if (RLang) 
+          AddUInt(&Buffer, DW_AT_APPLE_runtime_class, DW_FORM_data1, RLang);
       }
       break;
     default:
@@ -2800,6 +2803,9 @@ class DwarfDebug : public Dwarf {
       const std::string &Flags = DIUnit.getFlags();
       if (!Flags.empty())
         AddString(Die, DW_AT_APPLE_flags, DW_FORM_string, Flags);
+      unsigned RVer = DIUnit.getRunTimeVersion();
+      if (RVer)
+        AddUInt(Die, DW_AT_APPLE_major_runtime_vers, DW_FORM_data1, RVer);
 
       CompileUnit *Unit = new CompileUnit(ID, Die);
       if (DIUnit.isMain()) {

lib/Support/Dwarf.cpp

@@ -200,6 +200,8 @@ const char *AttributeString(unsigned Attribute) {
     case DW_AT_hi_user:                    return "DW_AT_hi_user";
     case DW_AT_APPLE_optimized:            return "DW_AT_APPLE_optimized";
     case DW_AT_APPLE_flags:                return "DW_AT_APPLE_flags";
+    case DW_AT_APPLE_major_runtime_vers:   return "DW_AT_APPLE_major_runtime_vers";
+    case DW_AT_APPLE_runtime_class:        return "DW_AT_APPLE_runtime_class";
   }
   assert(0 && "Unknown Dwarf Attribute");
   return "";

tools/lto/LTOCodeGenerator.cpp

@@ -356,6 +356,10 @@ bool LTOCodeGenerator::generateAssemblyCode(raw_ostream& out,
     // Add an appropriate TargetData instance for this module...
     passes.add(new TargetData(*_target->getTargetData()));
 
+    std::string targetTriple = _linker.getModule()->getTargetTriple();
+//    if ( targetTriple.find("darwin") != targetTriple.size() ) 
+        passes.add(createStripSymbolsPass(true /* strip debug info only */));
+
     // Propagate constants at call sites into the functions they call.  This
     // opens opportunities for globalopt (and inlining) by substituting function
     // pointers passed as arguments to direct uses of functions.  
@@ -412,6 +416,8 @@ bool LTOCodeGenerator::generateAssemblyCode(raw_ostream& out,
     // Make sure everything is still good.
     passes.add(createVerifierPass());
 
+    setCodeGenDebugOptions("-debug-pass=Structure");
+
     FunctionPassManager* codeGenPasses =
             new FunctionPassManager(new ExistingModuleProvider(mergedModule));