Add logic to the ObjC runtime in LLDB to extract the pointer values of the two singleton (pairtons?) instances of __NSCFBoolean that represent true and false

This is useful because that knowledge will in turn allow no-code-running formatting of boolean NSNumbers; but that's a commit that will have to wait Monday..

llvm-svn: 279353

lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp

@@ -350,6 +350,13 @@ AppleObjCRuntime::GetFoundationVersion ()
         return m_Foundation_major.getValue();
 }
 
+void
+AppleObjCRuntime::GetValuesForGlobalCFBooleans(lldb::addr_t& cf_true,
+                                               lldb::addr_t& cf_false)
+{
+    cf_true = cf_false = LLDB_INVALID_ADDRESS;
+}
+
 bool
 AppleObjCRuntime::IsModuleObjCLibrary (const ModuleSP &module_sp)
 {

lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.h

@@ -114,6 +114,10 @@ public:
     uint32_t
     GetFoundationVersion();
     
+    virtual void
+    GetValuesForGlobalCFBooleans(lldb::addr_t& cf_true,
+                                 lldb::addr_t& cf_false);
+    
 protected:
     // Call CreateInstance instead.
     AppleObjCRuntime(Process *process);

lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp

@@ -395,7 +395,8 @@ AppleObjCRuntimeV2::AppleObjCRuntimeV2(Process *process, const ModuleSP &objc_mo
       m_non_pointer_isa_cache_ap(NonPointerISACache::CreateInstance(*this, objc_module_sp)),
       m_tagged_pointer_vendor_ap(TaggedPointerVendorV2::CreateInstance(*this, objc_module_sp)),
       m_encoding_to_type_sp(),
-      m_noclasses_warning_emitted(false)
+      m_noclasses_warning_emitted(false),
+      m_CFBoolean_values()
 {
     static const ConstString g_gdb_object_getClass("gdb_object_getClass");
     m_has_object_getClass =
@@ -2577,3 +2578,44 @@ AppleObjCRuntimeV2::GetPointerISA (ObjCISA isa)
     
     return ret;
 }
+
+bool
+AppleObjCRuntimeV2::GetCFBooleanValuesIfNeeded ()
+{
+    if (m_CFBoolean_values)
+        return true;
+    
+    static ConstString g_kCFBooleanFalse("kCFBooleanFalse");
+    static ConstString g_kCFBooleanTrue("kCFBooleanTrue");
+    
+    std::function<lldb::addr_t(ConstString)> get_symbol = [this] (ConstString sym) -> lldb::addr_t {
+        SymbolContextList sc_list;
+        if (GetProcess()->GetTarget().GetImages().FindSymbolsWithNameAndType(g_kCFBooleanFalse, lldb::eSymbolTypeData, sc_list) == 1)
+        {
+            SymbolContext sc;
+            sc_list.GetContextAtIndex(0, sc);
+            if (sc.symbol)
+                return sc.symbol->GetLoadAddress(&GetProcess()->GetTarget());
+        }
+        
+        return LLDB_INVALID_ADDRESS;
+    };
+    
+    lldb::addr_t false_addr = get_symbol(g_kCFBooleanFalse);
+    lldb::addr_t true_addr = get_symbol(g_kCFBooleanTrue);
+    
+    return (m_CFBoolean_values = {false_addr,true_addr}).operator bool();
+}
+
+void
+AppleObjCRuntimeV2::GetValuesForGlobalCFBooleans(lldb::addr_t& cf_true,
+                                                 lldb::addr_t& cf_false)
+{
+    if (GetCFBooleanValuesIfNeeded())
+    {
+        cf_true = m_CFBoolean_values->second;
+        cf_false = m_CFBoolean_values->first;
+    }
+    else
+        this->AppleObjCRuntime::GetValuesForGlobalCFBooleans(cf_true, cf_false);
+}

lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.h

@@ -114,6 +114,10 @@ public:
         return m_tagged_pointer_vendor_ap.get();
     }
     
+    void
+    GetValuesForGlobalCFBooleans(lldb::addr_t& cf_true,
+                                 lldb::addr_t& cf_false) override;
+    
     // none of these are valid ISAs - we use them to infer the type
     // of tagged pointers - if we have something meaningful to say
     // we report an actual type - otherwise, we just say tagged
@@ -356,6 +360,9 @@ private:
     lldb::addr_t
     GetSharedCacheReadOnlyAddress();
     
+    bool
+    GetCFBooleanValuesIfNeeded ();
+    
     friend class ClassDescriptorV2;
 
     std::unique_ptr<UtilityFunction>        m_get_class_info_code;
@@ -375,6 +382,8 @@ private:
     std::unique_ptr<TaggedPointerVendor>    m_tagged_pointer_vendor_ap;
     EncodingToTypeSP                        m_encoding_to_type_sp;
     bool                                    m_noclasses_warning_emitted;
+    llvm::Optional<std::pair<lldb::addr_t,
+                             lldb::addr_t>>  m_CFBoolean_values;
 };
     
 } // namespace lldb_private