Revert "[LLVM] Add GNU make jobserver support (#145131)"

revert this patch due to failure in unittests/Support, e.g.

https://lab.llvm.org/buildbot/#/builders/33/builds/24178/steps/6/logs/FAIL__LLVM-Unit__SupportTests_61

This reverts commit ffc503e.

Author: yxsamliu

clang/include/clang/Driver/Options.td

@@ -1258,9 +1258,8 @@ def offload_compression_level_EQ : Joined<["--"], "offload-compression-level=">,
   HelpText<"Compression level for offload device binaries (HIP only)">;
 
 def offload_jobs_EQ : Joined<["--"], "offload-jobs=">,
-  HelpText<"Specify the number of threads to use for device offloading tasks "
-           "during compilation. Can be a positive integer or the string "
-           "'jobserver' to use the make-style jobserver from the environment.">;
+  HelpText<"Specify the number of threads to use for device offloading tasks"
+           " during compilation.">;
 
 defm offload_via_llvm : BoolFOption<"offload-via-llvm",
   LangOpts<"OffloadViaLLVM">, DefaultFalse,

clang/lib/Driver/ToolChains/Clang.cpp

@@ -9224,20 +9224,14 @@ void LinkerWrapper::ConstructJob(Compilation &C, const JobAction &JA,
   addOffloadCompressArgs(Args, CmdArgs);
 
   if (Arg *A = Args.getLastArg(options::OPT_offload_jobs_EQ)) {
-    StringRef Val = A->getValue();
-
-    if (Val.equals_insensitive("jobserver"))
-      CmdArgs.push_back(Args.MakeArgString("--wrapper-jobs=jobserver"));
-    else {
-      int NumThreads;
-      if (Val.getAsInteger(10, NumThreads) || NumThreads <= 0) {
-        C.getDriver().Diag(diag::err_drv_invalid_int_value)
-            << A->getAsString(Args) << Val;
-      } else {
-        CmdArgs.push_back(
-            Args.MakeArgString("--wrapper-jobs=" + Twine(NumThreads)));
-      }
-    }
+    int NumThreads;
+    if (StringRef(A->getValue()).getAsInteger(10, NumThreads) ||
+        NumThreads <= 0)
+      C.getDriver().Diag(diag::err_drv_invalid_int_value)
+          << A->getAsString(Args) << A->getValue();
+    else
+      CmdArgs.push_back(
+          Args.MakeArgString("--wrapper-jobs=" + Twine(NumThreads)));
   }
 
   const char *Exec =

clang/test/Driver/hip-options.hip

@@ -254,9 +254,3 @@
 // RUN:   --offload-arch=gfx1100 --offload-new-driver --offload-jobs=0x4 %s 2>&1 | \
 // RUN:   FileCheck -check-prefix=INVJOBS %s
 // INVJOBS: clang: error: invalid integral value '0x4' in '--offload-jobs=0x4'
-
-// RUN: %clang -### -Werror --target=x86_64-unknown-linux-gnu -nogpuinc -nogpulib \
-// RUN:   --offload-arch=gfx1100 --offload-new-driver --offload-jobs=jobserver %s 2>&1 | \
-// RUN:   FileCheck -check-prefix=JOBSV %s
-// JOBSV: clang-linker-wrapper{{.*}} "--wrapper-jobs=jobserver"
-

clang/test/Driver/linker-wrapper.c

@@ -114,8 +114,6 @@ __attribute__((visibility("protected"), used)) int x;
 // RUN:   -fembed-offload-object=%t.out
 // RUN: clang-linker-wrapper --dry-run --host-triple=x86_64-unknown-linux-gnu --wrapper-jobs=4 \
 // RUN: --linker-path=/usr/bin/ld %t.o -o a.out 2>&1 | FileCheck %s --check-prefix=CUDA-PAR
-// RUN: clang-linker-wrapper --dry-run --host-triple=x86_64-unknown-linux-gnu --wrapper-jobs=jobserver \
-// RUN: --linker-path=/usr/bin/ld %t.o -o a.out 2>&1 | FileCheck %s --check-prefix=CUDA-PAR
 
 // CUDA-PAR: fatbinary{{.*}}-64 --create {{.*}}.fatbin
 

clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp

@@ -1295,18 +1295,12 @@ int main(int Argc, char **Argv) {
 
   parallel::strategy = hardware_concurrency(1);
   if (auto *Arg = Args.getLastArg(OPT_wrapper_jobs)) {
-    StringRef Val = Arg->getValue();
-    if (Val.equals_insensitive("jobserver"))
-      parallel::strategy = jobserver_concurrency();
-    else {
-      unsigned Threads = 0;
-      if (!llvm::to_integer(Val, Threads) || Threads == 0)
-        reportError(createStringError(
-            "%s: expected a positive integer or 'jobserver', got '%s'",
-            Arg->getSpelling().data(), Val.data()));
-      else
-        parallel::strategy = hardware_concurrency(Threads);
-    }
+    unsigned Threads = 0;
+    if (!llvm::to_integer(Arg->getValue(), Threads) || Threads == 0)
+      reportError(createStringError("%s: expected a positive integer, got '%s'",
+                                    Arg->getSpelling().data(),
+                                    Arg->getValue()));
+    parallel::strategy = hardware_concurrency(Threads);
   }
 
   if (Args.hasArg(OPT_wrapper_time_trace_eq)) {

clang/tools/clang-linker-wrapper/LinkerWrapperOpts.td

@@ -53,8 +53,7 @@ def wrapper_time_trace_granularity : Joined<["--"], "wrapper-time-trace-granular
 
 def wrapper_jobs : Joined<["--"], "wrapper-jobs=">,
   Flags<[WrapperOnlyOption]>, MetaVarName<"<number>">,
-  HelpText<"Sets the number of parallel jobs for device linking. Can be a "
-            "positive integer or 'jobserver'.">;
+  HelpText<"Sets the number of parallel jobs to use for device linking">;
 
 def override_image : Joined<["--"], "override-image=">,
   Flags<[WrapperOnlyOption]>, MetaVarName<"<kind=file>">,

llvm/include/llvm/Support/Jobserver.h

@@ -16,7 +16,6 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Support/Compiler.h"
-#include "llvm/Support/Jobserver.h"
 #include "llvm/Support/RWMutex.h"
 #include "llvm/Support/Threading.h"
 #include "llvm/Support/thread.h"
@@ -181,7 +180,6 @@ class LLVM_ABI StdThreadPool : public ThreadPoolInterface {
   void grow(int requested);
 
   void processTasks(ThreadPoolTaskGroup *WaitingForGroup);
-  void processTasksWithJobserver();
 
   /// Threads in flight
   std::vector<llvm::thread> Threads;
@@ -210,8 +208,6 @@ class LLVM_ABI StdThreadPool : public ThreadPoolInterface {
 
   /// Maximum number of threads to potentially grow this pool to.
   const unsigned MaxThreadCount;
-
-  JobserverClient *TheJobserver = nullptr;
 };
 #endif // LLVM_ENABLE_THREADS
 

llvm/include/llvm/Support/ThreadPool.h

@@ -142,11 +142,6 @@ constexpr bool llvm_is_multithreaded() { return LLVM_ENABLE_THREADS; }
     /// the thread shall remain on the actual CPU socket.
     LLVM_ABI std::optional<unsigned>
     compute_cpu_socket(unsigned ThreadPoolNum) const;
-
-    /// If true, the thread pool will attempt to coordinate with a GNU Make
-    /// jobserver, acquiring a job slot before processing a task. If no
-    /// jobserver is found in the environment, this is ignored.
-    bool UseJobserver = false;
   };
 
   /// Build a strategy from a number of threads as a string provided in \p Num.
@@ -215,19 +210,6 @@ constexpr bool llvm_is_multithreaded() { return LLVM_ENABLE_THREADS; }
     return S;
   }
 
-  /// Returns a thread strategy that attempts to coordinate with a GNU Make
-  /// jobserver. The number of active threads will be limited by the number of
-  /// available job slots. If no jobserver is detected in the environment, this
-  /// strategy falls back to the default hardware_concurrency() behavior.
-  inline ThreadPoolStrategy jobserver_concurrency() {
-    ThreadPoolStrategy S;
-    S.UseJobserver = true;
-    // We can still request all threads be created, as they will simply
-    // block waiting for a job slot if the jobserver is the limiting factor.
-    S.ThreadsRequested = 0; // 0 means 'use all available'
-    return S;
-  }
-
   /// Return the current thread id, as used in various OS system calls.
   /// Note that not all platforms guarantee that the value returned will be
   /// unique across the entire system, so portable code should not assume

llvm/include/llvm/Support/Threading.h

@@ -207,7 +207,6 @@ add_llvm_component_library(LLVMSupport
   InstructionCost.cpp
   IntEqClasses.cpp
   IntervalMap.cpp
-  Jobserver.cpp
   JSON.cpp
   KnownBits.cpp
   KnownFPClass.cpp