[Legacy Driver] Obsolete and remove batch compilation mode from the legacy driver

It is a maintenance burden and having the legacy driver exist in a simplified state reduces the possibility of things going wrong and hitting old bugs.

Author: artemcm

include/swift/AST/DiagnosticsDriver.def

@@ -114,9 +114,6 @@ WARNING(warn_opt_remark_disabled, none,
         "requires a single compiler invocation: consider enabling the "
         "-whole-module-optimization flag", ())
 
-WARNING(warn_ignoring_batch_mode,none,
-"ignoring '-enable-batch-mode' because '%0' was also specified", (StringRef))
-
 WARNING(warn_ignoring_wmo, none,
         "ignoring '-wmo' because '-dump-ast' was also specified", ())
 

include/swift/AST/DiagnosticsFrontend.def

@@ -126,8 +126,6 @@ WARNING(warning_locale_path_not_found,none,
       "translation is disabled", (StringRef))
 WARNING(warning_cannot_find_locale_file,none,
       "cannot find translations for '%0' at '%1': no such file", (StringRef, StringRef))
-WARNING(warning_cannot_multithread_batch_mode,none,
-      "ignoring -num-threads argument; cannot multithread batch mode", ())
 ERROR(error_cannot_explicit_interface_build_in_mode,none,
       "'-explicit-interface-module-build' only supported when building a module from interface ('-compile-module-from-interface' or '-typecheck-module-from-interface')'", ())
 ERROR(error_unsupported_option_argument,none,

include/swift/Driver/Compilation.h

@@ -108,11 +108,11 @@ class Compilation {
   DiagnosticEngine &Diags;
 
   /// The ToolChain this Compilation was built with, that it may reuse to build
-  /// subsequent BatchJobs.
+  /// subsequent Jobs.
   const ToolChain &TheToolChain;
 
   /// The OutputInfo, which the Compilation stores a copy of upon
-  /// construction, and which it may use to build subsequent batch
+  /// construction, and which it may use to build subsequent
   /// jobs itself.
   OutputInfo TheOutputInfo;
 
@@ -167,22 +167,6 @@ class Compilation {
   /// even if they returned an error status.
   bool ContinueBuildingAfterErrors = false;
 
-  /// Indicates whether groups of parallel frontend jobs should be merged
-  /// together and run in composite "batch jobs" when possible, to reduce
-  /// redundant work.
-  const bool EnableBatchMode;
-
-  /// Provides a randomization seed to batch-mode partitioning, for debugging.
-  const unsigned BatchSeed;
-
-  /// Overrides parallelism level and \c BatchSizeLimit, sets exact
-  /// count of batches, if in batch-mode.
-  const std::optional<unsigned> BatchCount;
-
-  /// Overrides maximum batch size, if in batch-mode and not overridden
-  /// by \c BatchCount.
-  const std::optional<unsigned> BatchSizeLimit;
-
   /// True if temporary files should not be deleted.
   const bool SaveTemps;
 
@@ -244,10 +228,6 @@ class Compilation {
               std::unique_ptr<llvm::opt::DerivedArgList> TranslatedArgs,
               InputFileList InputsWithTypes,
               size_t FilelistThreshold,
-              bool EnableBatchMode = false,
-              unsigned BatchSeed = 0,
-              std::optional<unsigned> BatchCount = std::nullopt,
-              std::optional<unsigned> BatchSizeLimit = std::nullopt,
               bool SaveTemps = false,
               bool ShowDriverTimeCompilation = false,
               std::unique_ptr<UnifiedStatsReporter> Stats = nullptr,
@@ -302,10 +282,6 @@ class Compilation {
     return DerivedOutputFileMap;
   }
 
-  bool getBatchModeEnabled() const {
-    return EnableBatchMode;
-  }
-
   bool getContinueBuildingAfterErrors() const {
     return ContinueBuildingAfterErrors;
   }
@@ -352,14 +328,6 @@ class Compilation {
     return Level;
   }
 
-  unsigned getBatchSeed() const {
-    return BatchSeed;
-  }
-
-  std::optional<unsigned> getBatchCount() const { return BatchCount; }
-
-  std::optional<unsigned> getBatchSizeLimit() const { return BatchSizeLimit; }
-
   /// Requests the path to a file containing all input source files. This can
   /// be shared across jobs.
   ///
@@ -399,7 +367,7 @@ class Compilation {
   /// Unfortunately the success or failure of a Swift compilation is currently
   /// sensitive to the order in which files are processed, at least in terms of
   /// the order of processing extensions (and likely other ways we haven't
-  /// discovered yet). So long as this is true, we need to make sure any batch
+  /// discovered yet). So long as this is true, we need to make sure any
   /// job we build names its inputs in an order that's a subsequence of the
   /// sequence of inputs the driver was initially invoked with.
   ///

include/swift/Driver/Driver.h

@@ -67,19 +67,6 @@ class OutputInfo {
     /// A compilation using a single frontend invocation without -primary-file.
     SingleCompile,
 
-    /// A single process that batches together multiple StandardCompile Jobs.
-    ///
-    /// Note: this is a transient value to use _only_ for the individual
-    /// BatchJobs that are the temporary containers for multiple StandardCompile
-    /// Jobs built by ToolChain::constructBatchJob.
-    ///
-    /// In particular, the driver treats a batch-mode-enabled Compilation as
-    /// having OutputInfo::CompilerMode == StandardCompile, with the
-    /// Compilation::BatchModeEnabled flag set to true, _not_ as a
-    /// BatchModeCompile Compilation. The top-level OutputInfo::CompilerMode for
-    /// a Compilation should never be BatchModeCompile.
-    BatchModeCompile,
-
     /// Invoke the REPL
     REPL,
 
@@ -171,7 +158,7 @@ class Driver {
   /// allowable OutputInfo::Mode values.
   enum class DriverKind {
     Interactive,     // swift
-    Batch,           // swiftc
+    Standard,        // swiftc
     SILOpt,          // sil-opt
     SILFuncExtractor,// sil-func-extractor
     SILNM,           // sil-nm
@@ -313,14 +300,12 @@ class Driver {
   ///
   /// \param TC The current tool chain.
   /// \param Args The input arguments.
-  /// \param BatchMode Whether the driver has been explicitly or implicitly
-  /// instructed to use batch mode.
   /// \param Inputs The inputs to the driver.
   /// \param[out] OI The OutputInfo in which to store the resulting output
   /// information.
   void buildOutputInfo(const ToolChain &TC,
                        const llvm::opt::DerivedArgList &Args,
-                       const bool BatchMode, const InputFileList &Inputs,
+                       const InputFileList &Inputs,
                        OutputInfo &OI) const;
 
   /// Construct the list of Actions to perform for the given arguments,
@@ -472,11 +457,8 @@ class Driver {
   /// there is an actual conflict.
   /// \param Args The input arguments.
   /// \param Inputs The inputs to the driver.
-  /// \param BatchModeOut An out-parameter flag that indicates whether to
-  /// batch the jobs of the resulting \c Mode::StandardCompile compilation.
   OutputInfo::Mode computeCompilerMode(const llvm::opt::DerivedArgList &Args,
-                                       const InputFileList &Inputs,
-                                       bool &BatchModeOut) const;
+                                       const InputFileList &Inputs) const;
 };
 
 } // end namespace driver

include/swift/Driver/Job.h

@@ -389,8 +389,7 @@ class Job {
                                       StringRef Terminator = "\n") const;
 
   /// Call the provided Callback with any Jobs (and their possibly-quasi-PIDs)
-  /// contained within this Job; if this job is not a BatchJob, just pass \c
-  /// this and the provided \p OSPid back to the Callback.
+  /// contained within this Job;
   virtual void forEachContainedJobAndPID(
       llvm::sys::procid_t OSPid,
       llvm::function_ref<void(const Job *, Job::PID)> Callback) const {
@@ -411,51 +410,6 @@ class Job {
   StringRef getFirstSwiftPrimaryInput() const;
 };
 
-/// A BatchJob comprises a _set_ of jobs, each of which is sufficiently similar
-/// to the others that the whole set can be combined into a single subprocess
-/// (and thus run potentially more-efficiently than running each Job in the set
-/// individually).
-///
-/// Not all Jobs can be combined into a BatchJob: at present, only those Jobs
-/// that come from CompileJobActions, and which otherwise have the exact same
-/// input file list and arguments as one another, aside from their primary-file.
-/// See ToolChain::jobsAreBatchCombinable for details.
-
-class BatchJob : public Job {
-
-  /// The set of constituents making up the batch.
-  const SmallVector<const Job *, 4> CombinedJobs;
-
-  /// A negative number to use as the base value for assigning quasi-PID to Jobs
-  /// in the \c CombinedJobs array. Quasi-PIDs count _down_ from this value.
-  const Job::PID QuasiPIDBase;
-
-public:
-  BatchJob(const JobAction &Source, SmallVectorImpl<const Job *> &&Inputs,
-           std::unique_ptr<CommandOutput> Output, const char *Executable,
-           llvm::opt::ArgStringList Arguments,
-           EnvironmentVector ExtraEnvironment, std::vector<FilelistInfo> Infos,
-           ArrayRef<const Job *> Combined, Job::PID &NextQuasiPID,
-           std::optional<ResponseFileInfo> ResponseFile = std::nullopt);
-
-  ArrayRef<const Job*> getCombinedJobs() const {
-    return CombinedJobs;
-  }
-
-  /// Call the provided callback for each Job in the batch, passing the
-  /// corresponding quasi-PID with each Job.
-  void forEachContainedJobAndPID(
-      llvm::sys::procid_t OSPid,
-      llvm::function_ref<void(const Job *, Job::PID)> Callback) const override {
-    Job::PID QPid = QuasiPIDBase;
-    assert(QPid < 0);
-    for (auto const *J : CombinedJobs) {
-      assert(QPid != std::numeric_limits<Job::PID>::min());
-      Callback(J, QPid--);
-    }
-  }
-};
-
 } // end namespace driver
 } // end namespace swift
 

include/swift/Driver/ToolChain.h

@@ -98,7 +98,7 @@ class ToolChain {
     bool shouldUseSupplementaryOutputFileMapInFrontendInvocation() const;
 
     /// Reify the existing behavior that SingleCompile compile actions do not
-    /// filter, but batch-mode and single-file compilations do. Some clients are
+    /// filter, single-file compilations do. Some clients are
     /// relying on this (i.e., they pass inputs that don't have ".swift" as an
     /// extension.) It would be nice to eliminate this distinction someday.
     bool shouldFilterFrontendInputsByType() const;
@@ -281,33 +281,6 @@ class ToolChain {
                                     std::unique_ptr<CommandOutput> output,
                                     const OutputInfo &OI) const;
 
-  /// Return true iff the input \c Job \p A is an acceptable candidate for
-  /// batching together into a BatchJob, via a call to \c
-  /// constructBatchJob. This is true when the \c Job is a built from a \c
-  /// CompileJobAction in a \c Compilation \p C running in \c
-  /// OutputInfo::Mode::StandardCompile output mode, with a single \c TY_Swift
-  /// \c InputAction.
-  bool jobIsBatchable(const Compilation &C, const Job *A) const;
-
-  /// Equivalence relation that holds iff the two input Jobs \p A and \p B are
-  /// acceptable candidates for combining together into a \c BatchJob, via a
-  /// call to \c constructBatchJob. This is true when each job independently
-  /// satisfies \c jobIsBatchable, and the two jobs have identical executables,
-  /// output types and environments (i.e. they are identical aside from their
-  /// inputs).
-  bool jobsAreBatchCombinable(const Compilation &C, const Job *A,
-                              const Job *B) const;
-
-  /// Construct a \c BatchJob that subsumes the work of a set of Jobs. Any pair
-  /// of elements in \p Jobs are assumed to satisfy the equivalence relation \c
-  /// jobsAreBatchCombinable, i.e. they should all be "the same" job in in all
-  /// ways other than their choices of inputs. The provided \p NextQuasiPID
-  /// should be a negative number that persists between calls; this method will
-  /// decrement it to assign quasi-PIDs to each of the \p Jobs passed.
-  std::unique_ptr<Job> constructBatchJob(ArrayRef<const Job *> Jobs,
-                                         int64_t &NextQuasiPID,
-                                         Compilation &C) const;
-
   /// Return the default language type to use for the given extension.
   /// If the extension is empty or is otherwise not recognized, return
   /// the invalid type \c TY_INVALID.

include/swift/Option/Options.td

@@ -33,7 +33,7 @@ def ModuleWrapOption : OptionFlag;
 def NoDriverOption : OptionFlag;
 
 // Some options should not be available depending on whether this is the
-// interactive driver 'swift', or the batch compiler 'swiftc'.
+// interactive driver 'swift', or the aot compiler 'swiftc'.
 def NoInteractiveOption : OptionFlag;
 def NoBatchOption : OptionFlag;