From 20b5abe23b33b924a9f1a7ad62f3a9d9e118ebf5 Mon Sep 17 00:00:00 2001
From: Hans Wennborg <hans@hanshq.net>
Date: Wed, 26 Sep 2018 12:15:23 +0000
Subject: Revert r343058 "[ORC] Add support for multithreaded compiles to LLJIT
 and LLLazyJIT."

This doesn't work well in builds configured with LLVM_ENABLE_THREADS=OFF,
causing the following assert when running
ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll:

  lib/ExecutionEngine/Orc/Core.cpp:1748: Expected<llvm::JITEvaluatedSymbol>
  llvm::orc::lookup(const llvm::orc::JITDylibList &, llvm::orc::SymbolStringPtr):
  Assertion `ResultMap->size() == 1 && "Unexpected number of results"' failed.

> LLJIT and LLLazyJIT can now be constructed with an optional NumCompileThreads
> arguments. If this is non-zero then a thread-pool will be created with the
> given number of threads, and compile tasks will be dispatched to the thread
> pool.
>
> To enable testing of this feature, two new flags are added to lli:
>
> (1) -compile-threads=N (N = 0 by default) controls the number of compile threads
> to use.
>
> (2) -thread-entry can be used to execute code on additional threads. For each
> -thread-entry argument supplied (multiple are allowed) a new thread will be
> created and the given symbol called. These additional thread entry points are
> called after static constructors are run, but before main.

llvm-svn: 343099
---
 llvm/tools/lli/lli.cpp | 54 ++++++--------------------------------------------
 1 file changed, 6 insertions(+), 48 deletions(-)

(limited to 'llvm/tools/lli/lli.cpp')

diff --git a/llvm/tools/lli/lli.cpp b/llvm/tools/lli/lli.cpp
index 49d5db13326..2312d770348 100644
--- a/llvm/tools/lli/lli.cpp
+++ b/llvm/tools/lli/lli.cpp
@@ -97,17 +97,6 @@ namespace {
                                            "orc-lazy",
                                            "Orc-based lazy JIT.")));
 
-  cl::opt<unsigned>
-  LazyJITCompileThreads("compile-threads",
-                        cl::desc("Choose the number of compile threads "
-                                 "(jit-kind=orc-lazy only)"),
-                        cl::init(0));
-
-  cl::list<std::string>
-  ThreadEntryPoints("thread-entry",
-                    cl::desc("calls the given entry-point on a new thread "
-                             "(jit-kind=orc-lazy only)"));
-
   // The MCJIT supports building for a target address space separate from
   // the JIT compilation process. Use a forked process and a copying
   // memory manager with IPC to execute using this functionality.
@@ -374,19 +363,6 @@ int main(int argc, char **argv, char * const *envp) {
 
   if (UseJITKind == JITKind::OrcLazy)
     return runOrcLazyJIT(argv[0]);
-  else {
-    // Make sure nobody used an orc-lazy specific option accidentally.
-
-    if (LazyJITCompileThreads != 0) {
-      errs() << "-compile-threads requires -jit-kind=orc-lazy\n";
-      exit(1);
-    }
-
-    if (!ThreadEntryPoints.empty()) {
-      errs() << "-thread-entry requires -jit-kind=orc-lazy\n";
-      exit(1);
-    }
-  }
 
   LLVMContext Context;
 
@@ -769,11 +745,11 @@ int runOrcLazyJIT(const char *ProgName) {
     reportError(Err, ProgName);
 
   const auto &TT = MainModule.getModule()->getTargetTriple();
-  orc::JITTargetMachineBuilder JTMB =
+  orc::JITTargetMachineBuilder TMD =
       TT.empty() ? ExitOnErr(orc::JITTargetMachineBuilder::detectHost())
                  : orc::JITTargetMachineBuilder(Triple(TT));
 
-  JTMB.setArch(MArch)
+  TMD.setArch(MArch)
       .setCPU(getCPUStr())
       .addFeatures(getFeatureList())
       .setRelocationModel(RelocModel.getNumOccurrences()
@@ -782,13 +758,9 @@ int runOrcLazyJIT(const char *ProgName) {
       .setCodeModel(CMModel.getNumOccurrences()
                         ? Optional<CodeModel::Model>(CMModel)
                         : None);
-  DataLayout DL("");
-  {
-    // Create a throwaway TargetMachine to get the data layout.
-    auto TM = ExitOnErr(JTMB.createTargetMachine());
-    DL = TM->createDataLayout();
-  }
-  auto J = ExitOnErr(orc::LLLazyJIT::Create(std::move(JTMB), DL, LazyJITCompileThreads));
+  auto TM = ExitOnErr(TMD.createTargetMachine());
+  auto DL = TM->createDataLayout();
+  auto J = ExitOnErr(orc::LLLazyJIT::Create(std::move(TM), DL));
 
   auto Dump = createDebugDumper();
 
@@ -835,16 +807,6 @@ int runOrcLazyJIT(const char *ProgName) {
   // Run any static constructors.
   ExitOnErr(J->runConstructors());
 
-  // Run any -thread-entry points.
-  std::vector<std::thread> AltEntryThreads;
-  for (auto &ThreadEntryPoint : ThreadEntryPoints) {
-    auto EntryPointSym = ExitOnErr(J->lookup(ThreadEntryPoint));
-    typedef void (*EntryPointPtr)();
-    auto EntryPoint =
-      reinterpret_cast<EntryPointPtr>(static_cast<uintptr_t>(EntryPointSym.getAddress()));
-    AltEntryThreads.push_back(std::thread([EntryPoint]() { EntryPoint(); }));
-  }
-
   // Run main.
   auto MainSym = ExitOnErr(J->lookup("main"));
   typedef int (*MainFnPtr)(int, const char *[]);
@@ -855,12 +817,8 @@ int runOrcLazyJIT(const char *ProgName) {
       reinterpret_cast<MainFnPtr>(static_cast<uintptr_t>(MainSym.getAddress()));
   auto Result = Main(ArgV.size(), (const char **)ArgV.data());
 
-  // Wait for -entry-point threads.
-  for (auto &AltEntryThread : AltEntryThreads)
-    AltEntryThread.join();
-
-  // Run destructors.
   ExitOnErr(J->runDestructors());
+
   CXXRuntimeOverrides.runDestructors();
 
   return Result;
-- 
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