Merge pull request #8887 from huonw/emit-loaded-module-trace

[Frontend] -frontend -emit-loaded-module-trace.

Author: huonw

include/swift/AST/DiagnosticsFrontend.def

@@ -106,6 +106,8 @@ ERROR(error_mode_cannot_emit_dependencies,none,
   "this mode does not support emitting dependency files", ())
 ERROR(error_mode_cannot_emit_header,none,
   "this mode does not support emitting Objective-C headers", ())
+ERROR(error_mode_cannot_emit_loaded_module_trace,none,
+  "this mode does not support emitting the loaded module trace", ())
 ERROR(error_mode_cannot_emit_module,none,
   "this mode does not support emitting modules", ())
 ERROR(error_mode_cannot_emit_module_doc,none,

include/swift/Basic/JSONSerialization.h

@@ -445,6 +445,16 @@ class Output {
   void indent();
 };
 
+template <typename T> struct ArrayTraits<std::vector<T>> {
+  static size_t size(Output &out, std::vector<T> &seq) { return seq.size(); }
+
+  static T &element(Output &out, std::vector<T> &seq, size_t index) {
+    if (index >= seq.size())
+      seq.resize(index + 1);
+    return seq[index];
+  }
+};
+
 template<>
 struct ScalarTraits<bool> {
   static void output(const bool &, llvm::raw_ostream &);

include/swift/Driver/Compilation.h

@@ -146,6 +146,10 @@ class Compilation {
   /// detail than ShowIncrementalBuildDecisions.
   bool ShowJobLifecycle = false;
 
+  /// When true, some frontend job has requested permission to pass
+  /// -emit-loaded-module-trace, so no other job needs to do it.
+  bool PassedEmitLoadedModuleTraceToFrontendJob = false;
+
   static const Job *unwrap(const std::unique_ptr<const Job> &p) {
     return p.get();
   }
@@ -232,6 +236,22 @@ class Compilation {
   /// -2 indicates that one of the Compilation's Jobs crashed during execution
   int performJobs();
 
+  /// Returns whether the callee is permitted to pass -emit-loaded-module-trace
+  /// to a frontend job.
+  ///
+  /// This only returns true once, because only one job should pass that
+  /// argument.
+  bool requestPermissionForFrontendToEmitLoadedModuleTrace() {
+    if (PassedEmitLoadedModuleTraceToFrontendJob)
+      // Someone else has already done it!
+      return false;
+    else {
+      // We're the first and only (to execute this path).
+      PassedEmitLoadedModuleTraceToFrontendJob = true;
+      return true;
+    }
+  }
+
 private:
   /// \brief Perform all jobs.
   ///

include/swift/Driver/Types.def

@@ -59,6 +59,7 @@ TYPE("swift-dependencies", SwiftDeps,       "swiftdeps",       "")
 TYPE("remap",           Remapping,          "remap",           "")
 TYPE("imported-modules", ImportedModules,   "importedmodules", "")
 TYPE("tbd",             TBD,                "tbd",             "")
+TYPE("module-trace",    ModuleTrace,        "trace.json",      "")
 
 // Misc types
 TYPE("pcm",             ClangModuleFile,    "pcm",             "")

include/swift/Frontend/FrontendOptions.h

@@ -116,6 +116,9 @@ class FrontendOptions {
   /// The path to which we should output fixits as source edits.
   std::string FixitsOutputPath;
 
+  /// The path to which we should output a loaded module trace file.
+  std::string LoadedModuleTracePath;
+
   /// Arguments which should be passed in immediate mode.
   std::vector<std::string> ImmediateArgv;
 

include/swift/Option/Options.td

@@ -199,6 +199,16 @@ def emit_dependencies : Flag<["-"], "emit-dependencies">,
   Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>,
   HelpText<"Emit basic Make-compatible dependencies files">;
 
+def emit_loaded_module_trace : Flag<["-"], "emit-loaded-module-trace">,
+  Flags<[FrontendOption, NoInteractiveOption]>,
+  HelpText<"Emit a JSON file containing information about what modules were loaded">;
+def emit_loaded_module_trace_path : Separate<["-"], "emit-loaded-module-trace-path">,
+  Flags<[FrontendOption, NoInteractiveOption]>,
+  HelpText<"Emit the loaded module trace JSON to <path>">,
+  MetaVarName<"<path>">;
+def emit_loaded_module_trace_path_EQ : Joined<["-"], "emit-loaded-module-trace-path=">,
+  Flags<[FrontendOption, NoInteractiveOption]>, Alias<emit_loaded_module_trace_path>;
+
 def serialize_diagnostics : Flag<["-"], "serialize-diagnostics">,
   Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>,
   HelpText<"Serialize diagnostics in a binary format">;

lib/Driver/Driver.cpp

@@ -1421,6 +1421,7 @@ void Driver::buildActions(const ToolChain &TC,
       case types::TY_PCH:
       case types::TY_ImportedModules:
       case types::TY_TBD:
+      case types::TY_ModuleTrace:
         // We could in theory handle assembly or LLVM input, but let's not.
         // FIXME: What about LTO?
         Diags.diagnose(SourceLoc(), diag::error_unexpected_input_file,
@@ -1685,6 +1686,36 @@ void Driver::buildJobs(const ActionList &Actions, const OutputInfo &OI,
   }
 }
 
+static Optional<StringRef> getOutputFilenameFromPathArgOrAsTopLevel(
+    const OutputInfo &OI, const llvm::opt::DerivedArgList &Args,
+    llvm::opt::OptSpecifier PathArg, types::ID ExpectedOutputType,
+    bool TreatAsTopLevelOutput, StringRef ext, llvm::SmallString<128> &Buffer) {
+  if (const Arg *A = Args.getLastArg(PathArg))
+    return StringRef(A->getValue());
+
+  if (TreatAsTopLevelOutput) {
+    if (const Arg *A = Args.getLastArg(options::OPT_o)) {
+      if (OI.CompilerOutputType == ExpectedOutputType)
+        return StringRef(A->getValue());
+
+      // Otherwise, put the file next to the top-level output.
+      Buffer = A->getValue();
+      llvm::sys::path::remove_filename(Buffer);
+      llvm::sys::path::append(Buffer, OI.ModuleName);
+      llvm::sys::path::replace_extension(Buffer, ext);
+      return Buffer.str();
+    }
+
+    // A top-level output wasn't specified, so just output to
+    // <ModuleName>.<ext>.
+    Buffer = OI.ModuleName;
+    llvm::sys::path::replace_extension(Buffer, ext);
+    return Buffer.str();
+  }
+
+  return None;
+}
+
 static StringRef getOutputFilename(Compilation &C,
                                    const JobAction *JA,
                                    const OutputInfo &OI,
@@ -1707,29 +1738,14 @@ static StringRef getOutputFilename(Compilation &C,
 
   // Process Action-specific output-specifying options next,
   // since we didn't find anything applicable in the OutputMap.
-  if (isa<MergeModuleJobAction>(JA)) {
-    if (const Arg *A = Args.getLastArg(options::OPT_emit_module_path))
-      return A->getValue();
-
-    if (OI.ShouldTreatModuleAsTopLevelOutput) {
-      if (const Arg *A = Args.getLastArg(options::OPT_o)) {
-        if (OI.CompilerOutputType == types::TY_SwiftModuleFile)
-          return A->getValue();
-
-        // Otherwise, put the module next to the top-level output.
-        Buffer = A->getValue();
-        llvm::sys::path::remove_filename(Buffer);
-        llvm::sys::path::append(Buffer, OI.ModuleName);
-        llvm::sys::path::replace_extension(Buffer, SERIALIZED_MODULE_EXTENSION);
-        return Buffer.str();
-      }
 
-      // A top-level output wasn't specified, so just output to
-      // <ModuleName>.swiftmodule.
-      Buffer = OI.ModuleName;
-      llvm::sys::path::replace_extension(Buffer, SERIALIZED_MODULE_EXTENSION);
-      return Buffer.str();
-    }
+  if (isa<MergeModuleJobAction>(JA)) {
+    auto optFilename = getOutputFilenameFromPathArgOrAsTopLevel(
+        OI, Args, options::OPT_emit_module_path, types::TY_SwiftModuleFile,
+        OI.ShouldTreatModuleAsTopLevelOutput, SERIALIZED_MODULE_EXTENSION,
+        Buffer);
+    if (optFilename)
+      return *optFilename;
   }
 
   // dSYM actions are never treated as top-level.
@@ -2075,6 +2091,34 @@ Job *Driver::buildJobsForAction(Compilation &C, const JobAction *JA,
     if (C.getIncrementalBuildEnabled()) {
       addAuxiliaryOutput(C, *Output, types::TY_SwiftDeps, OI, OutputMap);
     }
+
+    // The loaded-module-trace is the same for all compile jobs: all `import`
+    // statements are processed, even ones from non-primary files. Thus, only
+    // one of those jobs needs to emit the file, and we can get it to write
+    // straight to the desired final location.
+    auto tracePathEnvVar = getenv("SWIFT_LOADED_MODULE_TRACE_PATH");
+    auto shouldEmitTrace =
+        tracePathEnvVar ||
+        C.getArgs().hasArg(options::OPT_emit_loaded_module_trace,
+                           options::OPT_emit_loaded_module_trace_path);
+
+    if (shouldEmitTrace &&
+        C.requestPermissionForFrontendToEmitLoadedModuleTrace()) {
+      StringRef filename;
+      // Prefer the environment variable.
+      if (tracePathEnvVar)
+        filename = StringRef(tracePathEnvVar);
+      else {
+        // By treating this as a top-level output, the return value always
+        // exists.
+        filename = *getOutputFilenameFromPathArgOrAsTopLevel(
+            OI, C.getArgs(), options::OPT_emit_loaded_module_trace_path,
+            types::TY_ModuleTrace,
+            /*TreatAsTopLevelOutput=*/true, "trace.json", Buf);
+      }
+
+      Output->setAdditionalOutputForType(types::TY_ModuleTrace, filename);
+    }
   }
 
   // Choose the Objective-C header output path.

lib/Driver/ToolChains.cpp

@@ -249,6 +249,7 @@ ToolChain::constructInvocation(const CompileJobAction &job,
     case types::TY_ObjCHeader:
     case types::TY_Image:
     case types::TY_SwiftDeps:
+    case types::TY_ModuleTrace:
       llvm_unreachable("Output type can never be primary output.");
     case types::TY_INVALID:
       llvm_unreachable("Invalid type ID");
@@ -388,6 +389,13 @@ ToolChain::constructInvocation(const CompileJobAction &job,
     Arguments.push_back(ReferenceDependenciesPath.c_str());
   }
 
+  const std::string &LoadedModuleTracePath =
+      context.Output.getAdditionalOutputForType(types::TY_ModuleTrace);
+  if (!LoadedModuleTracePath.empty()) {
+    Arguments.push_back("-emit-loaded-module-trace-path");
+    Arguments.push_back(LoadedModuleTracePath.c_str());
+  }
+
   const std::string &FixitsPath =
     context.Output.getAdditionalOutputForType(types::TY_Remapping);
   if (!FixitsPath.empty()) {
@@ -518,6 +526,7 @@ ToolChain::constructInvocation(const BackendJobAction &job,
     case types::TY_Image:
     case types::TY_SwiftDeps:
     case types::TY_Remapping:
+    case types::TY_ModuleTrace:
       llvm_unreachable("Output type can never be primary output.");
     case types::TY_INVALID:
       llvm_unreachable("Invalid type ID");

lib/Driver/Types.cpp

@@ -76,6 +76,7 @@ bool types::isTextual(ID Id) {
   case types::TY_AutolinkFile:
   case types::TY_ImportedModules:
   case types::TY_TBD:
+  case types::TY_ModuleTrace:
     return true;
   case types::TY_Image:
   case types::TY_Object:
@@ -127,6 +128,7 @@ bool types::isAfterLLVM(ID Id) {
   case types::TY_SwiftDeps:
   case types::TY_Nothing:
   case types::TY_Remapping:
+  case types::TY_ModuleTrace:
     return false;
   case types::TY_INVALID:
     llvm_unreachable("Invalid type ID.");
@@ -163,6 +165,7 @@ bool types::isPartOfSwiftCompilation(ID Id) {
   case types::TY_SwiftDeps:
   case types::TY_Nothing:
   case types::TY_Remapping:
+  case types::TY_ModuleTrace:
     return false;
   case types::TY_INVALID:
     llvm_unreachable("Invalid type ID.");

lib/Frontend/CompilerInvocation.cpp

@@ -676,6 +676,10 @@ static bool ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
                           OPT_emit_objc_header,
                           OPT_emit_objc_header_path,
                           "h", false);
+  determineOutputFilename(Opts.LoadedModuleTracePath,
+                          OPT_emit_loaded_module_trace,
+                          OPT_emit_loaded_module_trace_path,
+                          "trace.json", false);
 
   if (const Arg *A = Args.getLastArg(OPT_emit_fixits_path)) {
     Opts.FixitsOutputPath = A->getValue();
@@ -765,6 +769,39 @@ static bool ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
     }
   }
 
+  if (!Opts.LoadedModuleTracePath.empty()) {
+    switch (Opts.RequestedAction) {
+    case FrontendOptions::NoneAction:
+    case FrontendOptions::Parse:
+    case FrontendOptions::DumpParse:
+    case FrontendOptions::DumpInterfaceHash:
+    case FrontendOptions::DumpAST:
+    case FrontendOptions::PrintAST:
+    case FrontendOptions::DumpScopeMaps:
+    case FrontendOptions::DumpTypeRefinementContexts:
+    case FrontendOptions::Immediate:
+    case FrontendOptions::REPL:
+    case FrontendOptions::UpdateCode:
+      Diags.diagnose(SourceLoc(),
+                     diag::error_mode_cannot_emit_loaded_module_trace);
+      return true;
+    case FrontendOptions::Typecheck:
+    case FrontendOptions::EmitModuleOnly:
+    case FrontendOptions::EmitPCH:
+    case FrontendOptions::EmitSILGen:
+    case FrontendOptions::EmitSIL:
+    case FrontendOptions::EmitSIBGen:
+    case FrontendOptions::EmitSIB:
+    case FrontendOptions::EmitIR:
+    case FrontendOptions::EmitBC:
+    case FrontendOptions::EmitAssembly:
+    case FrontendOptions::EmitObject:
+    case FrontendOptions::EmitImportedModules:
+    case FrontendOptions::EmitTBD:
+      break;
+    }
+  }
+
   if (!Opts.ModuleOutputPath.empty() ||
       !Opts.ModuleDocOutputPath.empty()) {
     switch (Opts.RequestedAction) {