Add frontend options to write SIL and LLVM IR as additional compilation output.

This commit adds -sil-output-path and -ir-output-path frontend options that
allow generating SIL and LLVM IR files as supplementary outputs during normal
compilation.

These options can be useful for debugging and analysis tools
workflows that need access to intermediate compilation artifacts
without requiring separate compiler invocations.

Expected behaviour:

Primary File mode:
 - SIL: Generates one .sil file per source file
 - IR: Generates one .ll file per source file

Single-threaded WMO mode:
 - SIL: Generates one .sil file for the entire module
 - IR: Generates one .ll file for the entire module

Multi-threaded WMO mode:
 - SIL: Generates one .sil file for the entire module
 - IR: Generates separate .ll files per source file

File Maps with WMO:
 - Both SIL and IR outputs using first entry's naming, which is
   consistent with the behaviour of other supplementary outputs.

rdar://160297898

Author: rjmansfield

include/swift/AST/IRGenRequests.h

@@ -151,6 +151,7 @@ struct IRGenDescriptor {
   const PrimarySpecificPaths &PSPs;
   StringRef PrivateDiscriminator;
   ArrayRef<std::string> parallelOutputFilenames;
+  ArrayRef<std::string> parallelIROutputFilenames;
   llvm::GlobalVariable **outModuleHash;
   llvm::raw_pwrite_stream *out = nullptr;
 
@@ -188,6 +189,7 @@ struct IRGenDescriptor {
                            PSPs,
                            PrivateDiscriminator,
                            {},
+                           {},
                            outModuleHash};
   }
 
@@ -197,6 +199,7 @@ struct IRGenDescriptor {
       std::unique_ptr<SILModule> &&SILMod, StringRef ModuleName,
       const PrimarySpecificPaths &PSPs, SymsToEmit symsToEmit = std::nullopt,
       ArrayRef<std::string> parallelOutputFilenames = {},
+      ArrayRef<std::string> parallelIROutputFilenames = {},
       llvm::GlobalVariable **outModuleHash = nullptr) {
     return IRGenDescriptor{M,
                            symsToEmit,
@@ -209,6 +212,7 @@ struct IRGenDescriptor {
                            PSPs,
                            "",
                            parallelOutputFilenames,
+                           parallelIROutputFilenames,
                            outModuleHash};
   }
 

include/swift/Basic/SupplementaryOutputPaths.def

@@ -166,3 +166,9 @@ OUTPUT(YAMLOptRecordPath, TY_YAMLOptRecord)
 
 /// The output path for bitstream optimization record file.
 OUTPUT(BitstreamOptRecordPath, TY_BitstreamOptRecord)
+
+/// The output path to which we should output SIL as extra compilation output.
+OUTPUT(SILOutputPath, TY_SIL)
+
+/// The output path to which we should output LLVM IR as extra compilation output.
+OUTPUT(LLVMIROutputPath, TY_LLVM_IR)

include/swift/FrontendTool/FrontendTool.h

@@ -79,7 +79,8 @@ int performFrontend(ArrayRef<const char *> args,
                     FrontendObserver *observer = nullptr);
 
 bool performCompileStepsPostSema(CompilerInstance &Instance, int &ReturnValue,
-                                 FrontendObserver *observer);
+                                 FrontendObserver *observer,
+                                 ArrayRef<const char *> CommandLineArgs);
 
 } // namespace swift
 

include/swift/Option/FrontendOptions.td

@@ -63,6 +63,18 @@ def emit_module_semantic_info_path
   : Separate<["-"], "emit-module-semantic-info-path">, MetaVarName<"<path>">,
     HelpText<"Output semantic info of current module to <path>">;
 
+def sil_output_path
+  : Separate<["-"], "sil-output-path">, MetaVarName<"<path>">,
+    Flags<[FrontendOption, NoInteractiveOption, ArgumentIsPath,
+           SupplementaryOutput, CacheInvariant]>,
+    HelpText<"Output SIL to <path> as additional output during compilation">;
+
+def ir_output_path
+  : Separate<["-"], "ir-output-path">, MetaVarName<"<path>">,
+    Flags<[FrontendOption, NoInteractiveOption, ArgumentIsPath,
+           SupplementaryOutput, CacheInvariant]>,
+    HelpText<"Output LLVM IR to <path> as additional output during compilation">;
+
 def diagnostic_documentation_path
   : Separate<["-"], "diagnostic-documentation-path">, MetaVarName<"<path>">,
   HelpText<"Path to diagnostic documentation resources">;
@@ -266,7 +278,7 @@ def serialize_dependency_scan_cache : Flag<["-"], "serialize-dependency-scan-cac
 
 def reuse_dependency_scan_cache : Flag<["-"], "load-dependency-scan-cache">,
    HelpText<"For performing a dependency scan, deserialize the scanner's internal state from a prior scan.">;
-   
+
 def validate_prior_dependency_scan_cache : Flag<["-"], "validate-prior-dependency-scan-cache">,
    HelpText<"For performing a dependency scan with a prior scanner state, validate module dependencies.">;
 

include/swift/Subsystems.h

@@ -250,9 +250,10 @@ namespace swift {
   GeneratedModule
   performIRGeneration(ModuleDecl *M, const IRGenOptions &Opts,
                       const TBDGenOptions &TBDOpts,
-                      std::unique_ptr<SILModule> SILMod,
-                      StringRef ModuleName, const PrimarySpecificPaths &PSPs,
+                      std::unique_ptr<SILModule> SILMod, StringRef ModuleName,
+                      const PrimarySpecificPaths &PSPs,
                       ArrayRef<std::string> parallelOutputFilenames,
+                      ArrayRef<std::string> parallelIROutputFilenames,
                       llvm::GlobalVariable **outModuleHash = nullptr);
 
   /// Turn the given Swift file into LLVM IR and return the generated module.

lib/Driver/ToolChains.cpp

@@ -953,6 +953,12 @@ void ToolChain::JobContext::addFrontendSupplementaryOutputArguments(
   addOutputsOfType(arguments, Output, Args,
                    file_types::TY_SwiftModuleSummaryFile,
                    "-emit-module-summary-path");
+
+  // Add extra output paths for SIL and LLVM IR
+  addOutputsOfType(arguments, Output, Args, file_types::TY_SIL,
+                   "-sil-output-path");
+  addOutputsOfType(arguments, Output, Args, file_types::TY_LLVM_IR,
+                   "-ir-output-path");
 }
 
 ToolChain::InvocationInfo
@@ -1237,6 +1243,12 @@ ToolChain::constructInvocation(const MergeModuleJobAction &job,
   addOutputsOfType(Arguments, context.Output, context.Args, file_types::TY_TBD,
                    "-emit-tbd-path");
 
+  // Add extra output paths for SIL and LLVM IR
+  addOutputsOfType(Arguments, context.Output, context.Args, file_types::TY_SIL,
+                   "-sil-output-path");
+  addOutputsOfType(Arguments, context.Output, context.Args,
+                   file_types::TY_LLVM_IR, "-ir-output-path");
+
   context.Args.AddLastArg(Arguments, options::OPT_emit_symbol_graph);
   context.Args.AddLastArg(Arguments, options::OPT_emit_symbol_graph_dir);
   context.Args.AddLastArg(Arguments, options::OPT_include_spi_symbols);

lib/Frontend/ArgsToFrontendOutputsConverter.cpp

@@ -275,15 +275,15 @@ SupplementaryOutputPathsComputer::computeOutputPaths() const {
 
   if (InputsAndOutputs.hasPrimaryInputs())
     assert(OutputFiles.size() == pathsFromUser->size());
-  else if (InputsAndOutputs.isSingleThreadedWMO())
-    assert(OutputFiles.size() == pathsFromUser->size() &&
-           pathsFromUser->size() == 1);
   else {
-    // Multi-threaded WMO is the exception
-    assert(OutputFiles.size() == InputsAndOutputs.inputCount() &&
-           pathsFromUser->size() == (InputsAndOutputs.hasInputs() ? 1 : 0));
+    if (!InputsAndOutputs.isSingleThreadedWMO()) {
+      assert(OutputFiles.size() == InputsAndOutputs.inputCount());
+    }
+    assert(pathsFromUser->size() == 1 ||
+           pathsFromUser->size() == InputsAndOutputs.inputCount());
   }
 
+  // For other cases, process the paths normally
   std::vector<SupplementaryOutputPaths> outputPaths;
   unsigned i = 0;
   bool hadError = InputsAndOutputs.forEachInputProducingSupplementaryOutput(
@@ -380,18 +380,52 @@ SupplementaryOutputPathsComputer::getSupplementaryOutputPathsFromArguments()
       options::OPT_emit_module_semantic_info_path);
   auto optRecordOutput = getSupplementaryFilenamesFromArguments(
       options::OPT_save_optimization_record_path);
+  auto silOutput =
+      getSupplementaryFilenamesFromArguments(options::OPT_sil_output_path);
+  auto irOutput =
+      getSupplementaryFilenamesFromArguments(options::OPT_ir_output_path);
   if (!clangHeaderOutput || !moduleOutput || !moduleDocOutput ||
       !dependenciesFile || !referenceDependenciesFile ||
       !serializedDiagnostics || !loadedModuleTrace || !TBD ||
-      !moduleInterfaceOutput || !privateModuleInterfaceOutput || !packageModuleInterfaceOutput ||
-      !moduleSourceInfoOutput || !moduleSummaryOutput || !abiDescriptorOutput ||
-      !moduleSemanticInfoOutput || !optRecordOutput) {
+      !moduleInterfaceOutput || !privateModuleInterfaceOutput ||
+      !packageModuleInterfaceOutput || !moduleSourceInfoOutput ||
+      !moduleSummaryOutput || !abiDescriptorOutput ||
+      !moduleSemanticInfoOutput || !optRecordOutput || !silOutput ||
+      !irOutput) {
     return std::nullopt;
   }
   std::vector<SupplementaryOutputPaths> result;
 
-  const unsigned N =
-      InputsAndOutputs.countOfFilesProducingSupplementaryOutput();
+  // In WMO mode with multiple IR output paths, we need to create one
+  // SupplementaryOutputPaths per input file, not just one for the module
+  unsigned N = InputsAndOutputs.countOfFilesProducingSupplementaryOutput();
+  if (!InputsAndOutputs.hasPrimaryInputs() && irOutput->size() > 1) {
+    // WMO mode with multiple IR outputs: use input count instead of 1
+    N = InputsAndOutputs.inputCount();
+  }
+
+  // Find the index of SIL output path matching module name
+  auto findSILIndexForModuleName = [&]() -> unsigned {
+    if (!InputsAndOutputs.hasPrimaryInputs() && silOutput->size() > 1) {
+      // In WMO mode with multiple SIL output paths, find the one whose matches
+      // module name
+      for (unsigned i = 0; i < silOutput->size(); ++i) {
+        StringRef silPath = (*silOutput)[i];
+        if (!silPath.empty()) {
+          StringRef basename = llvm::sys::path::stem(silPath);
+          if (basename == ModuleName) {
+            return i;
+          }
+        }
+      }
+      // If no match found, fall back to first
+      return 0;
+    }
+    return 0;
+  };
+
+  unsigned silOutputIndex = findSILIndexForModuleName();
+
   for (unsigned i = 0; i < N; ++i) {
     SupplementaryOutputPaths sop;
     sop.ClangHeaderOutputPath = (*clangHeaderOutput)[i];
@@ -413,6 +447,8 @@ SupplementaryOutputPathsComputer::getSupplementaryOutputPathsFromArguments()
     sop.ModuleSemanticInfoOutputPath = (*moduleSemanticInfoOutput)[i];
     sop.YAMLOptRecordPath = (*optRecordOutput)[i];
     sop.BitstreamOptRecordPath = (*optRecordOutput)[i];
+    sop.SILOutputPath = (*silOutput)[silOutputIndex];
+    sop.LLVMIROutputPath = (*irOutput)[i];
     result.push_back(sop);
   }
   return result;
@@ -439,6 +475,15 @@ SupplementaryOutputPathsComputer::getSupplementaryFilenamesFromArguments(
       paths.emplace_back();
     return paths;
   }
+  // Special handling for SIL and IR output paths: allow multiple paths per file
+  // type
+  else if ((pathID == options::OPT_sil_output_path ||
+            pathID == options::OPT_ir_output_path) &&
+           paths.size() > N) {
+    // For parallel compilation, we can have multiple SIL/IR output paths
+    // so return all the paths.
+    return paths;
+  }
 
   if (paths.empty())
     return std::vector<std::string>(N, std::string());
@@ -613,6 +658,9 @@ SupplementaryOutputPathsComputer::computeOutputPathsForOneInput(
       file_types::TY_BitstreamOptRecord, "",
       defaultSupplementaryOutputPathExcludingExtension);
 
+  auto SILOutputPath = pathsFromArguments.SILOutputPath;
+  auto LLVMIROutputPath = pathsFromArguments.LLVMIROutputPath;
+
   SupplementaryOutputPaths sop;
   sop.ClangHeaderOutputPath = clangHeaderOutputPath;
   sop.ModuleOutputPath = moduleOutputPath;
@@ -635,6 +683,8 @@ SupplementaryOutputPathsComputer::computeOutputPathsForOneInput(
   sop.ModuleSemanticInfoOutputPath = ModuleSemanticInfoOutputPath;
   sop.YAMLOptRecordPath = YAMLOptRecordPath;
   sop.BitstreamOptRecordPath = bitstreamOptRecordPath;
+  sop.SILOutputPath = SILOutputPath;
+  sop.LLVMIROutputPath = LLVMIROutputPath;
   return sop;
 }
 
@@ -741,18 +791,18 @@ createFromTypeToPathMap(const TypeToPathMap *map) {
 
 std::optional<std::vector<SupplementaryOutputPaths>>
 SupplementaryOutputPathsComputer::readSupplementaryOutputFileMap() const {
-  if (Arg *A = Args.getLastArg(options::OPT_emit_objc_header_path,
-                               options::OPT_emit_module_path,
-                               options::OPT_emit_module_doc_path,
-                               options::OPT_emit_dependencies_path,
-                               options::OPT_emit_reference_dependencies_path,
-                               options::OPT_serialize_diagnostics_path,
-                               options::OPT_emit_loaded_module_trace_path,
-                               options::OPT_emit_module_interface_path,
-                               options::OPT_emit_private_module_interface_path,
-                               options::OPT_emit_package_module_interface_path,
-                               options::OPT_emit_module_source_info_path,
-                               options::OPT_emit_tbd_path)) {
+  if (Arg *A = Args.getLastArg(
+          options::OPT_emit_objc_header_path, options::OPT_emit_module_path,
+          options::OPT_emit_module_doc_path,
+          options::OPT_emit_dependencies_path,
+          options::OPT_emit_reference_dependencies_path,
+          options::OPT_serialize_diagnostics_path,
+          options::OPT_emit_loaded_module_trace_path,
+          options::OPT_emit_module_interface_path,
+          options::OPT_emit_private_module_interface_path,
+          options::OPT_emit_package_module_interface_path,
+          options::OPT_emit_module_source_info_path, options::OPT_emit_tbd_path,
+          options::OPT_sil_output_path, options::OPT_ir_output_path)) {
     Diags.diagnose(SourceLoc(),
                    diag::error_cannot_have_supplementary_outputs,
                    A->getSpelling(), "-supplementary-output-file-map");