From 592afe73ada21856f908a42486378b2860037ebd Mon Sep 17 00:00:00 2001
From: Enrico Granata <egranata@apple.com>
Date: Tue, 15 Mar 2016 21:50:51 +0000
Subject: [PATCH] Improve the 'type lookup' command such that it guesses to use
 the current's frame language as the one to start searching from.

llvm-svn: 263592
---
 lldb/include/lldb/Target/StackFrame.h      |  5 +++++
 lldb/source/Commands/CommandObjectType.cpp | 29 ++++++++++++++++++++++++++++-
 lldb/source/Target/StackFrame.cpp          | 20 +++++++++++++++++++-
 3 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/lldb/include/lldb/Target/StackFrame.h b/lldb/include/lldb/Target/StackFrame.h
index b65b018..f021cba 100644
--- a/lldb/include/lldb/Target/StackFrame.h
+++ b/lldb/include/lldb/Target/StackFrame.h
@@ -478,6 +478,11 @@ public:
     lldb::LanguageType
     GetLanguage ();
 
+    // similar to GetLanguage(), but is allowed to take a potentially incorrect guess
+    // if exact information is not available
+    lldb::LanguageType
+    GuessLanguage ();
+    
     //------------------------------------------------------------------
     // lldb::ExecutionContextScope pure virtual functions
     //------------------------------------------------------------------
diff --git a/lldb/source/Commands/CommandObjectType.cpp b/lldb/source/Commands/CommandObjectType.cpp
index 971506b..f291f11 100644
--- a/lldb/source/Commands/CommandObjectType.cpp
+++ b/lldb/source/Commands/CommandObjectType.cpp
@@ -11,6 +11,7 @@
 
 // C Includes
 // C++ Includes
+#include <algorithm>
 #include <cctype>
 #include <functional>
 
@@ -3344,7 +3345,9 @@ public:
         
         std::vector<Language*> languages;
         
-        if (m_command_options.m_language == eLanguageTypeUnknown)
+        bool is_global_search = false;
+
+        if ( (is_global_search = (m_command_options.m_language == eLanguageTypeUnknown)) )
         {
             // FIXME: hardcoding languages is not good
             languages.push_back(Language::FindPlugin(eLanguageTypeObjC));
@@ -3355,6 +3358,27 @@ public:
             languages.push_back(Language::FindPlugin(m_command_options.m_language));
         }
         
+        // This is not the most efficient way to do this, but we support very few languages
+        // so the cost of the sort is going to be dwarfed by the actual lookup anyway
+        if (StackFrame* frame = m_exe_ctx.GetFramePtr())
+        {
+            LanguageType lang = frame->GuessLanguage();
+            if (lang != eLanguageTypeUnknown)
+            {
+                std::sort(languages.begin(),
+                          languages.end(),
+                          [lang] (Language* lang1,
+                                  Language* lang2) -> bool {
+                              if (!lang1 || !lang2) return false;
+                              LanguageType lt1 = lang1->GetLanguageType();
+                              LanguageType lt2 = lang2->GetLanguageType();
+                              if (lt1 == lang) return true; // make the selected frame's language come first
+                              if (lt2 == lang) return false; // make the selected frame's language come first
+                              return (lt1 < lt2); // normal comparison otherwise
+                          });
+            }
+        }
+        
         for (Language* language : languages)
         {
             if (!language)
@@ -3374,6 +3398,9 @@ public:
                         }
                     }
                 }
+                // this is "type lookup SomeName" and we did find a match, so get out
+                if (any_found && is_global_search)
+                    break;
             }
         }
         
diff --git a/lldb/source/Target/StackFrame.cpp b/lldb/source/Target/StackFrame.cpp
index 1d1a68f..37dc67b 100644
--- a/lldb/source/Target/StackFrame.cpp
+++ b/lldb/source/Target/StackFrame.cpp
@@ -12,10 +12,11 @@
 // Other libraries and framework includes
 // Project includes
 #include "lldb/Target/StackFrame.h"
-#include "lldb/Core/Module.h"
 #include "lldb/Core/Debugger.h"
 #include "lldb/Core/Disassembler.h"
 #include "lldb/Core/FormatEntity.h"
+#include "lldb/Core/Mangled.h"
+#include "lldb/Core/Module.h"
 #include "lldb/Core/Value.h"
 #include "lldb/Core/ValueObjectVariable.h"
 #include "lldb/Core/ValueObjectConstResult.h"
@@ -1356,6 +1357,23 @@ StackFrame::GetLanguage ()
     return lldb::eLanguageTypeUnknown;
 }
 
+lldb::LanguageType
+StackFrame::GuessLanguage ()
+{
+    LanguageType lang_type = GetLanguage();
+    
+    if (lang_type == eLanguageTypeUnknown)
+    {
+        Function *f = GetSymbolContext(eSymbolContextFunction).function;
+        if (f)
+        {
+            lang_type = f->GetMangled().GuessLanguage();
+        }
+    }
+    
+    return lang_type;
+}
+
 TargetSP
 StackFrame::CalculateTarget ()
 {
-- 
2.7.4