commit f9d16476573e16856bdb3250c817b0a2c631d2b1
author Pavel Labath <labath@google.com> Mon May 15 13:02:37 2017 +0000
committer Pavel Labath <labath@google.com> Mon May 15 13:02:37 2017 +0000
tree 7cae9a3d7fb178078ab0e4990ebf991c93679c08
parent 3030bf0c816b136c97d8c69ca8b38e394eefd5d2

Remove an expensive lock from Timer

The Timer destructor would grab a global mutex in order to update
execution time. Add a class to define a category once, statically; the
class adds itself to an atomic singly linked list, and thus subsequent
updates only need to use an atomic rather than grab a lock and perform a
hashtable lookup.

Differential Revision: https://reviews.llvm.org/D32823
Patch by Scott Smith <scott.smith@purestorage.com>.

llvm-svn: 303058

lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
index 4551966..ad009a0 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
@@ -991,7 +991,8 @@
     const ConstString &name, const CompilerDeclContext *parent_decl_ctx,
     uint32_t name_type_mask, bool include_inlines, bool append,
     SymbolContextList &sc_list) {
-  Timer scoped_timer(LLVM_PRETTY_FUNCTION,
+  static Timer::Category func_cat(LLVM_PRETTY_FUNCTION);
+  Timer scoped_timer(func_cat,
                      "SymbolFileDWARFDebugMap::FindFunctions (name = %s)",
                      name.GetCString());
 
@@ -1018,7 +1019,8 @@
                                                 bool include_inlines,
                                                 bool append,
                                                 SymbolContextList &sc_list) {
-  Timer scoped_timer(LLVM_PRETTY_FUNCTION,
+  static Timer::Category func_cat(LLVM_PRETTY_FUNCTION);
+  Timer scoped_timer(func_cat,
                      "SymbolFileDWARFDebugMap::FindFunctions (regex = '%s')",
                      regex.GetText().str().c_str());
 
@@ -1044,7 +1046,8 @@
 size_t SymbolFileDWARFDebugMap::GetTypes(SymbolContextScope *sc_scope,
                                          uint32_t type_mask,
                                          TypeList &type_list) {
-  Timer scoped_timer(LLVM_PRETTY_FUNCTION,
+  static Timer::Category func_cat(LLVM_PRETTY_FUNCTION);
+  Timer scoped_timer(func_cat,
                      "SymbolFileDWARFDebugMap::GetTypes (type_mask = 0x%8.8x)",
                      type_mask);