[lldb] change MemoryHistoryASan::CreateInstance to not look into all modules, but only in the executable and libclang_rt.asan dynamic library

[kubamracek]

Summary

For better performance, let's change the code that checks whether there is an ASan runtime library present to only look into

1. the main executable, and
2. a dynamic library of the name starting with "libclang_rt.asan_" and ending with "_dynamic.dylib".

[kubamracek]

This already landed a long time ago.

source/Plugins/MemoryHistory/asan/MemoryHistoryASan.cpp

 #include "lldb/Target/Thread.h"
 #include "lldb/Core/Module.h"
 #include "Plugins/Process/Utility/HistoryThread.h"
 #include "lldb/Core/ValueObject.h"
 
 using namespace lldb;
 using namespace lldb_private;
 
+bool ModuleContainsASanRuntime(Module * module)
+{
+    SymbolContextList sc_list;
+    const bool include_symbols = true;
+    const bool append = true;
+    const bool include_inlines = true;
+    
+    size_t num_matches = module->FindFunctions(ConstString("__asan_get_alloc_stack"), NULL, eFunctionNameTypeAuto, include_symbols, include_inlines, append, sc_list);
+    
+    return num_matches > 0;
+}
+
 MemoryHistorySP
 MemoryHistoryASan::CreateInstance (const ProcessSP &process_sp)
 {
     if (!process_sp.get())
         return NULL;
     
     Target & target = process_sp->GetTarget();
     
-    bool found_asan_runtime = false;
+    Module *exe_module = target.GetExecutableModulePointer();
+    if (exe_module)
+    {
+        if (ModuleContainsASanRuntime(exe_module))
+        {
+            return MemoryHistorySP(new MemoryHistoryASan(process_sp));
+        }
+    }
     
     const ModuleList &target_modules = target.GetImages();
     Mutex::Locker modules_locker(target_modules.GetMutex());
     const size_t num_modules = target_modules.GetSize();
     for (size_t i = 0; i < num_modules; ++i)
     {
         Module *module_pointer = target_modules.GetModulePointerAtIndexUnlocked(i);
-        
-        SymbolContextList sc_list;
-        const bool include_symbols = true;
-        const bool append = true;
-        const bool include_inlines = true;
-
-        size_t num_matches = module_pointer->FindFunctions(ConstString("__asan_get_alloc_stack"), NULL, eFunctionNameTypeAuto, include_symbols, include_inlines, append, sc_list);
+        const FileSpec & file_spec = module_pointer->GetFileSpec();
+        if (! file_spec)
+        {
+            continue;
+        }
+        static RegularExpression g_asan_runtime_regex("libclang_rt.asan_(.*)_dynamic\\.dylib");
+        if (! g_asan_runtime_regex.Execute (file_spec.GetFilename().GetCString()))
+        {
+            continue;
+        }
         
-        if (num_matches)
+        if (ModuleContainsASanRuntime(module_pointer))
         {
-            found_asan_runtime = true;
-            break;
+            return MemoryHistorySP(new MemoryHistoryASan(process_sp));
         }
     }
     
-    if (! found_asan_runtime)
-        return MemoryHistorySP();
-
-    return MemoryHistorySP(new MemoryHistoryASan(process_sp));
+    // not found
 }
 
 void
 MemoryHistoryASan::Initialize()
 {
     PluginManager::RegisterPlugin (GetPluginNameStatic(),
                                    "ASan memory history provider.",
                                    CreateInstance);