================ @@ -0,0 +1,257 @@ +//===- llvm/Support/Jobserver.cpp - Jobserver Client Implementation -------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "llvm/Support/Jobserver.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/Config/llvm-config.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/Error.h" +#include "llvm/Support/raw_ostream.h" + +#include <atomic> +#include <memory> +#include <mutex> +#include <new> + +#define DEBUG_TYPE "jobserver" + +using namespace llvm; + +namespace { +struct JobserverConfig { + enum Mode { + None, + PosixFifo, + PosixPipe, + Win32Semaphore, + }; + Mode TheMode = None; + std::string Path; + int ReadFD = -1; + int WriteFD = -1; +}; + +/// A helper function that checks if `Input` starts with `Prefix`. +/// If it does, it removes the prefix from `Input`, assigns the remainder to +/// `Value`, and returns true. Otherwise, it returns false. +bool getPrefixedValue(StringRef Input, StringRef Prefix, StringRef &Value) { + if (Input.consume_front(Prefix)) { + Value = Input; + return true; + } + return false; +} + +/// A helper function to parse a string in the format "R,W" where R and W are +/// non-negative integers representing file descriptors. It populates the +/// `ReadFD` and `WriteFD` output parameters. Returns true on success. +bool getFileDescriptorPair(StringRef Input, int &ReadFD, int &WriteFD) { + if (sscanf(Input.str().c_str(), "%d,%d", &ReadFD, &WriteFD) != 2) + return false; + return ReadFD >= 0 && WriteFD >= 0; +} + +/// Parses the `MAKEFLAGS` environment variable string to find jobserver +/// arguments. It splits the string into space-separated arguments and searches +/// for `--jobserver-auth` or `--jobserver-fds`. Based on the value of these +/// arguments, it determines the jobserver mode (Pipe, FIFO, or Semaphore) and +/// connection details (file descriptors or path). +Expected<JobserverConfig> parseNativeMakeFlags(StringRef MakeFlags) { + JobserverConfig Config; + if (MakeFlags.empty()) + return Config; + + // Split the MAKEFLAGS string into arguments. + SmallVector<StringRef, 8> Args; + StringRef S = MakeFlags; + while (!S.empty()) { + size_t Start = S.find_first_not_of(" \t"); + if (Start == StringRef::npos) + break; + S = S.substr(Start); + size_t End = S.find_first_of(" \t"); + if (End == StringRef::npos) { + Args.push_back(S); + break; + } + Args.push_back(S.substr(0, End)); + S = S.substr(End); + } + + // If '-n' (dry-run) is present as a legacy flag (not starting with '-'), + // disable the jobserver. + if (!Args.empty() && !Args[0].starts_with("-") && Args[0].contains('n')) + return Config; + + // Iterate through arguments to find jobserver flags. + // Note that make may pass multiple --jobserver-auth flags; the last one wins. + for (StringRef Arg : Args) { + StringRef Value; + if (getPrefixedValue(Arg, "--jobserver-auth=", Value)) { + int R, W; + // Try to parse as a file descriptor pair first. + if (getFileDescriptorPair(Value, R, W)) { + Config.TheMode = JobserverConfig::PosixPipe; + Config.ReadFD = R; + Config.WriteFD = W; + } else { + StringRef FifoPath; + // If not FDs, try to parse as a named pipe (fifo). + if (getPrefixedValue(Value, "fifo:", FifoPath)) { + Config.TheMode = JobserverConfig::PosixFifo; + Config.Path = FifoPath.str(); + } else { + // Otherwise, assume it's a Windows semaphore. + Config.TheMode = JobserverConfig::Win32Semaphore; + Config.Path = Value.str(); + } + } + } else if (getPrefixedValue(Arg, "--jobserver-fds=", Value)) { + // This is an alternative, older syntax for the pipe-based server. + int R, W; + if (getFileDescriptorPair(Value, R, W)) { + Config.TheMode = JobserverConfig::PosixPipe; + Config.ReadFD = R; + Config.WriteFD = W; + } else { + return createStringError(inconvertibleErrorCode(), + "Invalid file descriptor pair in MAKEFLAGS"); + } + } + } + +// Perform platform-specific validation. +#ifdef _WIN32 + if (Config.TheMode == JobserverConfig::PosixFifo || + Config.TheMode == JobserverConfig::PosixPipe) + return createStringError( + inconvertibleErrorCode(), + "FIFO/Pipe-based jobserver is not supported on Windows"); +#else + if (Config.TheMode == JobserverConfig::Win32Semaphore) + return createStringError( + inconvertibleErrorCode(), + "Semaphore-based jobserver is not supported on this platform"); +#endif + return Config; +} + +std::once_flag GJobserverOnceFlag; +JobserverClient *GJobserver = nullptr; + +} // namespace + +namespace llvm { +class JobserverClientImpl : public JobserverClient { + bool IsInitialized = false; + std::atomic<bool> HasImplicitSlot{true}; + unsigned NumJobs = 0; + +public: + JobserverClientImpl(const JobserverConfig &Config); + ~JobserverClientImpl() override; + + JobSlot tryAcquire() override; + void release(JobSlot Slot) override; + unsigned getNumJobs() const override { return NumJobs; } + + bool isValid() const { return IsInitialized; } + +private: +#if defined(LLVM_ON_UNIX) + int ReadFD = -1; + int WriteFD = -1; + std::string FifoPath; +#elif defined(_WIN32) + void *Semaphore = nullptr; +#endif +}; +} // namespace llvm + +// Include the platform-specific parts of the class. +#if defined(LLVM_ON_UNIX) +#include "Unix/Jobserver.inc" +#elif defined(_WIN32) +#include "Windows/Jobserver.inc" +#endif ---------------- Artem-B wrote:
Should there be an `#else #error ...` here? https://github.com/llvm/llvm-project/pull/145131 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
