[Lldb-commits] [lldb] r250832 - Revert "Make dwarf parsing multi-threaded"
Zachary Turner via lldb-commits
lldb-commits at lists.llvm.org
Tue Oct 20 09:00:47 PDT 2015
This is kind of why I pushed back against this in the first place :-/ It's
hard to get right.
I still wish we could find a way to use standard library facilities for
this, either by splitting the compile units into hardware_concurrency
chunks, or kicking off no more than hardware_concurrency compile units at a
time, and having them all share a mutex around a queue of compilation
units, so that when each one's work is finished, it can queue the next item
(if one still exists).
On Tue, Oct 20, 2015 at 8:45 AM Tamas Berghammer via lldb-commits <
lldb-commits at lists.llvm.org> wrote:
> Author: tberghammer
> Date: Tue Oct 20 10:43:40 2015
> New Revision: 250832
>
> URL: http://llvm.org/viewvc/llvm-project?rev=250832&view=rev
> Log:
> Revert "Make dwarf parsing multi-threaded"
>
> Revert it bacuse it introduces several race condition detected by
> the build bots.
>
> This reverts commit 5107a5ebdb7c4571a30a7098b40bf8098b678447.
>
> Modified:
> lldb/trunk/source/Plugins/SymbolFile/DWARF/NameToDIE.cpp
> lldb/trunk/source/Plugins/SymbolFile/DWARF/NameToDIE.h
> lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
>
> Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/NameToDIE.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/SymbolFile/DWARF/NameToDIE.cpp?rev=250832&r1=250831&r2=250832&view=diff
>
> ==============================================================================
> --- lldb/trunk/source/Plugins/SymbolFile/DWARF/NameToDIE.cpp (original)
> +++ lldb/trunk/source/Plugins/SymbolFile/DWARF/NameToDIE.cpp Tue Oct 20
> 10:43:40 2015
> @@ -83,14 +83,3 @@ NameToDIE::ForEach (std::function <bool(
> break;
> }
> }
> -
> -void
> -NameToDIE::Append (const NameToDIE& other)
> -{
> - const uint32_t size = other.m_map.GetSize();
> - for (uint32_t i = 0; i < size; ++i)
> - {
> - m_map.Append(other.m_map.GetCStringAtIndexUnchecked (i),
> - other.m_map.GetValueAtIndexUnchecked (i));
> - }
> -}
>
> Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/NameToDIE.h
> URL:
> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/SymbolFile/DWARF/NameToDIE.h?rev=250832&r1=250831&r2=250832&view=diff
>
> ==============================================================================
> --- lldb/trunk/source/Plugins/SymbolFile/DWARF/NameToDIE.h (original)
> +++ lldb/trunk/source/Plugins/SymbolFile/DWARF/NameToDIE.h Tue Oct 20
> 10:43:40 2015
> @@ -38,9 +38,6 @@ public:
> Insert (const lldb_private::ConstString& name, const DIERef& die_ref);
>
> void
> - Append (const NameToDIE& other);
> -
> - void
> Finalize();
>
> size_t
>
> Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp?rev=250832&r1=250831&r2=250832&view=diff
>
> ==============================================================================
> --- lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
> (original)
> +++ lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp Tue Oct
> 20 10:43:40 2015
> @@ -50,8 +50,6 @@
>
> #include "lldb/Target/Language.h"
>
> -#include "lldb/Utility/TaskPool.h"
> -
> #include "DWARFASTParser.h"
> #include "DWARFCompileUnit.h"
> #include "DWARFDebugAbbrev.h"
> @@ -2037,72 +2035,40 @@ SymbolFileDWARF::Index ()
> "SymbolFileDWARF::Index (%s)",
>
> GetObjectFile()->GetFileSpec().GetFilename().AsCString("<Unknown>"));
>
> -
> -
> DWARFDebugInfo* debug_info = DebugInfo();
> if (debug_info)
> {
> + uint32_t cu_idx = 0;
> const uint32_t num_compile_units = GetNumCompileUnits();
> - std::vector<NameToDIE> function_basename_index(num_compile_units);
> - std::vector<NameToDIE> function_fullname_index(num_compile_units);
> - std::vector<NameToDIE> function_method_index(num_compile_units);
> - std::vector<NameToDIE> function_selector_index(num_compile_units);
> - std::vector<NameToDIE>
> objc_class_selectors_index(num_compile_units);
> - std::vector<NameToDIE> global_index(num_compile_units);
> - std::vector<NameToDIE> type_index(num_compile_units);
> - std::vector<NameToDIE> namespace_index(num_compile_units);
> -
> - auto parser_fn = [this,
> - debug_info,
> - &function_basename_index,
> - &function_fullname_index,
> - &function_method_index,
> - &function_selector_index,
> - &objc_class_selectors_index,
> - &global_index,
> - &type_index,
> - &namespace_index](uint32_t cu_idx)
> + for (cu_idx = 0; cu_idx < num_compile_units; ++cu_idx)
> {
> DWARFCompileUnit* dwarf_cu =
> debug_info->GetCompileUnitAtIndex(cu_idx);
> - bool clear_dies = dwarf_cu->ExtractDIEsIfNeeded(false) > 1;
>
> - dwarf_cu->Index(function_basename_index[cu_idx],
> - function_fullname_index[cu_idx],
> - function_method_index[cu_idx],
> - function_selector_index[cu_idx],
> - objc_class_selectors_index[cu_idx],
> - global_index[cu_idx],
> - type_index[cu_idx],
> - namespace_index[cu_idx]);
> + bool clear_dies = dwarf_cu->ExtractDIEsIfNeeded (false) > 1;
>
> + dwarf_cu->Index (m_function_basename_index,
> + m_function_fullname_index,
> + m_function_method_index,
> + m_function_selector_index,
> + m_objc_class_selectors_index,
> + m_global_index,
> + m_type_index,
> + m_namespace_index);
> +
> // Keep memory down by clearing DIEs if this generate function
> // caused them to be parsed
> if (clear_dies)
> - dwarf_cu->ClearDIEs(true);
> - };
> -
> - std::vector<std::future<void>> results;
> - for (uint32_t cu_idx = 0; cu_idx < num_compile_units; ++cu_idx)
> - results.emplace_back(TaskPool::AddTask(parser_fn, cu_idx));
> - for (auto& f : results)
> - f.wait();
> -
> - auto merge_fn = [](NameToDIE& target, const
> std::vector<NameToDIE>& sources)
> - {
> - for (const auto& src : sources)
> - target.Append(src);
> - target.Finalize();
> - };
> -
> - TaskPool::RunTasks(
> - [&]() { merge_fn(m_function_basename_index,
> function_basename_index); },
> - [&]() { merge_fn(m_function_fullname_index,
> function_fullname_index); },
> - [&]() { merge_fn(m_function_method_index,
> function_method_index); },
> - [&]() { merge_fn(m_function_selector_index,
> function_selector_index); },
> - [&]() { merge_fn(m_objc_class_selectors_index,
> objc_class_selectors_index); },
> - [&]() { merge_fn(m_global_index, global_index); },
> - [&]() { merge_fn(m_type_index, type_index); },
> - [&]() { merge_fn(m_namespace_index, namespace_index); });
> + dwarf_cu->ClearDIEs (true);
> + }
> +
> + m_function_basename_index.Finalize();
> + m_function_fullname_index.Finalize();
> + m_function_method_index.Finalize();
> + m_function_selector_index.Finalize();
> + m_objc_class_selectors_index.Finalize();
> + m_global_index.Finalize();
> + m_type_index.Finalize();
> + m_namespace_index.Finalize();
>
> #if defined (ENABLE_DEBUG_PRINTF)
> StreamFile s(stdout, false);
>
>
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