From a9afed75456715bafec7cf9df952fa493a77424b Mon Sep 17 00:00:00 2001 From: Chandler Carruth Date: Sat, 4 Jun 2016 07:25:44 +0000 Subject: [PATCH] [LPM] Reinstate r271652 to replace the CALL_ONCE_... macro in the legacy pass manager with the new llvm::call_once facility. This reverts commit r271657 and re-applies r271652 with a fix to actually work with arguments. In the original version, we just ended up directly calling std::call_once via ADL because of the std::once_flag argument. The llvm::call_once never worked with arguments. Now, llvm::call_once is a variadic template that perfectly forwards everything. As a part of this it had to move to the header and we use a generic functor rather than an explict function pointer. It would be nice to use std::invoke here but we don't have it yet. That means pointer to members won't work here, but that seems a tolerable compromise. I've also tested this by forcing the fallback path, so hopefully it sticks this time. Original commit message: ---- [LPM] Replace the CALL_ONCE_... macro in the legacy pass manager with the new llvm::call_once facility. This facility matches the standard APIs and when the platform supports it actually directly uses the standard provided functionality. This is both more efficient on some platforms and much more TSan friendly. The only remaining user of the cas_flag and home-rolled atomics is the fallback implementation of call_once. I have a patch that removes them entirely, but it needs a Windows patch to land first. This alone substantially cleans up the macros for the legacy pass manager, and should subsume some of the work Mehdi was doing to clear the path for TSan testing of ThinLTO, a really important step to have reliable upstream testing of ThinLTO in all forms. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271781 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/CodeGen/Passes.h | 4 ++- include/llvm/PassSupport.h | 43 +++++++++++++------------------- include/llvm/Support/Threading.h | 31 ++++++++++++++++++++++- lib/Support/ManagedStatic.cpp | 2 +- lib/Support/Threading.cpp | 27 -------------------- 5 files changed, 52 insertions(+), 55 deletions(-) diff --git a/include/llvm/CodeGen/Passes.h b/include/llvm/CodeGen/Passes.h index 1e01d66a2ce..6c85c250cbb 100644 --- a/include/llvm/CodeGen/Passes.h +++ b/include/llvm/CodeGen/Passes.h @@ -377,8 +377,10 @@ namespace llvm { Registry.registerPass(*PI, true); \ return PI; \ } \ + LLVM_DEFINE_ONCE_FLAG(Initialize##passName##PassFlag); \ void llvm::initialize##passName##Pass(PassRegistry &Registry) { \ - CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \ + llvm::call_once(Initialize##passName##PassFlag, \ + initialize##passName##PassOnce, std::ref(Registry)); \ } /// This initializer registers TargetMachine constructor, so the pass being diff --git a/include/llvm/PassSupport.h b/include/llvm/PassSupport.h index f205c001f53..ba6d84f04ba 100644 --- a/include/llvm/PassSupport.h +++ b/include/llvm/PassSupport.h @@ -26,31 +26,13 @@ #include "llvm/PassInfo.h" #include "llvm/PassRegistry.h" #include "llvm/Support/Atomic.h" +#include "llvm/Support/Threading.h" +#include namespace llvm { class TargetMachine; -#define CALL_ONCE_INITIALIZATION(function) \ - static volatile sys::cas_flag initialized = 0; \ - sys::cas_flag old_val = sys::CompareAndSwap(&initialized, 1, 0); \ - if (old_val == 0) { \ - function(Registry); \ - sys::MemoryFence(); \ - TsanIgnoreWritesBegin(); \ - TsanHappensBefore(&initialized); \ - initialized = 2; \ - TsanIgnoreWritesEnd(); \ - } else { \ - sys::cas_flag tmp = initialized; \ - sys::MemoryFence(); \ - while (tmp != 2) { \ - tmp = initialized; \ - sys::MemoryFence(); \ - } \ - } \ - TsanHappensAfter(&initialized); - #define INITIALIZE_PASS(passName, arg, name, cfg, analysis) \ static void *initialize##passName##PassOnce(PassRegistry &Registry) { \ PassInfo *PI = new PassInfo( \ @@ -59,8 +41,10 @@ class TargetMachine; Registry.registerPass(*PI, true); \ return PI; \ } \ + LLVM_DEFINE_ONCE_FLAG(Initialize##passName##PassFlag); \ void llvm::initialize##passName##Pass(PassRegistry &Registry) { \ - CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \ + llvm::call_once(Initialize##passName##PassFlag, \ + initialize##passName##PassOnce, std::ref(Registry)); \ } #define INITIALIZE_PASS_BEGIN(passName, arg, name, cfg, analysis) \ @@ -77,8 +61,10 @@ class TargetMachine; Registry.registerPass(*PI, true); \ return PI; \ } \ + LLVM_DEFINE_ONCE_FLAG(Initialize##passName##PassFlag); \ void llvm::initialize##passName##Pass(PassRegistry &Registry) { \ - CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \ + llvm::call_once(Initialize##passName##PassFlag, \ + initialize##passName##PassOnce, std::ref(Registry)); \ } #define INITIALIZE_PASS_WITH_OPTIONS(PassName, Arg, Name, Cfg, Analysis) \ @@ -166,8 +152,11 @@ struct RegisterAnalysisGroup : public RegisterAGBase { Registry.registerAnalysisGroup(&agName::ID, 0, *AI, false, true); \ return AI; \ } \ + LLVM_DEFINE_ONCE_FLAG(Initialize##agName##AnalysisGroupFlag); \ void llvm::initialize##agName##AnalysisGroup(PassRegistry &Registry) { \ - CALL_ONCE_INITIALIZATION(initialize##agName##AnalysisGroupOnce) \ + llvm::call_once(Initialize##agName##AnalysisGroupFlag, \ + initialize##agName##AnalysisGroupOnce, \ + std::ref(Registry)); \ } #define INITIALIZE_AG_PASS(passName, agName, arg, name, cfg, analysis, def) \ @@ -184,8 +173,10 @@ struct RegisterAnalysisGroup : public RegisterAGBase { true); \ return AI; \ } \ + LLVM_DEFINE_ONCE_FLAG(Initialize##passName##PassFlag); \ void llvm::initialize##passName##Pass(PassRegistry &Registry) { \ - CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \ + llvm::call_once(Initialize##passName##PassFlag, \ + initialize##passName##PassOnce, std::ref(Registry)); \ } #define INITIALIZE_AG_PASS_BEGIN(passName, agName, arg, n, cfg, analysis, def) \ @@ -203,8 +194,10 @@ struct RegisterAnalysisGroup : public RegisterAGBase { Registry.registerAnalysisGroup(&agName::ID, &passName::ID, *AI, def, true); \ return AI; \ } \ + LLVM_DEFINE_ONCE_FLAG(Initialize##passName##PassFlag); \ void llvm::initialize##passName##Pass(PassRegistry &Registry) { \ - CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \ + llvm::call_once(Initialize##passName##PassFlag, \ + initialize##passName##PassOnce, std::ref(Registry)); \ } //===--------------------------------------------------------------------------- diff --git a/include/llvm/Support/Threading.h b/include/llvm/Support/Threading.h index b51d1f97fa9..9804dd8aff6 100644 --- a/include/llvm/Support/Threading.h +++ b/include/llvm/Support/Threading.h @@ -16,7 +16,9 @@ #define LLVM_SUPPORT_THREADING_H #include "llvm/Config/llvm-config.h" // for LLVM_ON_UNIX +#include "llvm/Support/Compiler.h" #include // So we can check the C++ standard lib macros. +#include // We use std::call_once on all Unix platforms except for NetBSD with // libstdc++. That platform has a bug they are working to fix, and they'll @@ -84,7 +86,34 @@ namespace llvm { /// /// \param flag Flag used for tracking whether or not this has run. /// \param UserFn Function to call once. - void call_once(once_flag &flag, void (*UserFn)(void)); + template + void call_once(once_flag &flag, Function &&F, Args &&... ArgList) { +#if LLVM_THREADING_USE_STD_CALL_ONCE + std::call_once(flag, std::forward(F), + std::forward(ArgList)...); +#else + // For other platforms we use a generic (if brittle) version based on our + // atomics. + sys::cas_flag old_val = sys::CompareAndSwap(&flag, Wait, Uninitialized); + if (old_val == Uninitialized) { + std::forward(F)(std::forward(ArgList)...); + sys::MemoryFence(); + TsanIgnoreWritesBegin(); + TsanHappensBefore(&flag); + flag = Done; + TsanIgnoreWritesEnd(); + } else { + // Wait until any thread doing the call has finished. + sys::cas_flag tmp = flag; + sys::MemoryFence(); + while (tmp != Done) { + tmp = flag; + sys::MemoryFence(); + } + } + TsanHappensAfter(&flag); +#endif + } } #endif diff --git a/lib/Support/ManagedStatic.cpp b/lib/Support/ManagedStatic.cpp index b1feddc09ec..bc4fe954e22 100644 --- a/lib/Support/ManagedStatic.cpp +++ b/lib/Support/ManagedStatic.cpp @@ -32,7 +32,7 @@ static sys::Mutex* getManagedStaticMutex() { // We need to use a function local static here, since this can get called // during a static constructor and we need to guarantee that it's initialized // correctly. - call_once(mutex_init_flag, initializeMutex); + llvm::call_once(mutex_init_flag, initializeMutex); return ManagedStaticMutex; } diff --git a/lib/Support/Threading.cpp b/lib/Support/Threading.cpp index de2ff6b4fae..e8f5622d0e5 100644 --- a/lib/Support/Threading.cpp +++ b/lib/Support/Threading.cpp @@ -116,30 +116,3 @@ void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData, } #endif - -void llvm::call_once(once_flag &flag, void (*fptr)(void)) { -#if LLVM_THREADING_USE_STD_CALL_ONCE - std::call_once(flag, fptr); -#else - // For other platforms we use a generic (if brittle) version based on our - // atomics. - sys::cas_flag old_val = sys::CompareAndSwap(&flag, Wait, Uninitialized); - if (old_val == Uninitialized) { - fptr(); - sys::MemoryFence(); - TsanIgnoreWritesBegin(); - TsanHappensBefore(&flag); - flag = Done; - TsanIgnoreWritesEnd(); - } else { - // Wait until any thread doing the call has finished. - sys::cas_flag tmp = flag; - sys::MemoryFence(); - while (tmp != Done) { - tmp = flag; - sys::MemoryFence(); - } - } - TsanHappensAfter(&flag); -#endif -}