[flang] Move parser invocations into ParserActions (#130309)

FrontendActions.cpp is currently one of the biggest compilation units in
all of flang. Measuring its compilation gives the following metrics:

User time (seconds): 139.21
System time (seconds): 4.65
Maximum resident set size (kbytes): 5891440 (5.61 GB)

This commit separates out explicit invocations of the parser into a
separate compilation unit - ParserActions.cpp - through helper functions
in order to decrease the maximum compilation time and memory usage of a
single unit.
After the split, the measurements of FrontendActions.cpp are as follows:

User time (seconds): 70.08
System time (seconds): 3.16
Maximum resident set size (kbytes): 3961492 (3.7 GB)

While the ones for the newly created ParserActions.cpp as follows:

User time (seconds): 104.33
System time (seconds): 3.37
Maximum resident set size (kbytes): 4185600 (3.99 GB)

---------

Signed-off-by: Kajetan Puchalski <[email protected]>

Author: mrkajetanp

flang/include/flang/Frontend/CompilerInstance.h

@@ -15,9 +15,8 @@
 
 #include "flang/Frontend/CompilerInvocation.h"
 #include "flang/Frontend/FrontendAction.h"
+#include "flang/Frontend/ParserActions.h"
 #include "flang/Frontend/PreprocessorOptions.h"
-#include "flang/Parser/parsing.h"
-#include "flang/Parser/provenance.h"
 #include "flang/Semantics/runtime-type-info.h"
 #include "flang/Semantics/semantics.h"
 #include "flang/Support/StringOstream.h"

flang/include/flang/Frontend/CompilerInvocation.h

@@ -18,7 +18,7 @@
 #include "flang/Frontend/PreprocessorOptions.h"
 #include "flang/Frontend/TargetOptions.h"
 #include "flang/Lower/LoweringOptions.h"
-#include "flang/Parser/parsing.h"
+#include "flang/Parser/options.h"
 #include "flang/Semantics/semantics.h"
 #include "flang/Support/LangOptions.h"
 #include "mlir/Support/Timing.h"
@@ -29,7 +29,7 @@
 
 namespace llvm {
 class TargetMachine;
-}
+} // namespace llvm
 
 namespace Fortran::frontend {
 

flang/include/flang/Frontend/FrontendActions.h

@@ -13,10 +13,8 @@
 #ifndef FORTRAN_FRONTEND_FRONTENDACTIONS_H
 #define FORTRAN_FRONTEND_FRONTENDACTIONS_H
 
-#include "flang/Frontend/CodeGenOptions.h"
 #include "flang/Frontend/FrontendAction.h"
-#include "flang/Parser/parsing.h"
-#include "flang/Semantics/semantics.h"
+#include "flang/Frontend/ParserActions.h"
 
 #include "mlir/IR/BuiltinOps.h"
 #include "mlir/IR/OwningOpRef.h"
@@ -26,21 +24,6 @@
 
 namespace Fortran::frontend {
 
-// TODO: This is a copy from f18.cpp. It doesn't really belong here and should
-// be moved to a more suitable place in future.
-struct MeasurementVisitor {
-  template <typename A>
-  bool Pre(const A &) {
-    return true;
-  }
-  template <typename A>
-  void Post(const A &) {
-    ++objects;
-    bytes += sizeof(A);
-  }
-  size_t objects{0}, bytes{0};
-};
-
 //===----------------------------------------------------------------------===//
 // Custom Consumer Actions
 //===----------------------------------------------------------------------===//

flang/include/flang/Frontend/ParserActions.h

@@ -0,0 +1,67 @@
+//===- ParserActions.h -------------------------------------------*- C++-*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_PARSER_ACTIONS_H_
+#define FORTRAN_PARSER_ACTIONS_H_
+
+#include <string>
+
+namespace llvm {
+class raw_string_ostream;
+class raw_ostream;
+class StringRef;
+} // namespace llvm
+
+namespace Fortran::lower {
+class LoweringBridge;
+} // namespace Fortran::lower
+
+namespace Fortran::parser {
+class Parsing;
+class AllCookedSources;
+} // namespace Fortran::parser
+
+namespace lower::pft {
+class Program;
+} // namespace lower::pft
+
+//=== Frontend Parser helpers ===
+
+namespace Fortran::frontend {
+class CompilerInstance;
+
+parser::AllCookedSources &getAllCooked(CompilerInstance &ci);
+
+void parseAndLowerTree(CompilerInstance &ci, lower::LoweringBridge &lb);
+
+void dumpTree(CompilerInstance &ci);
+
+void dumpProvenance(CompilerInstance &ci);
+
+void dumpPreFIRTree(CompilerInstance &ci);
+
+void formatOrDumpPrescanner(std::string &buf,
+                            llvm::raw_string_ostream &outForPP,
+                            CompilerInstance &ci);
+
+void debugMeasureParseTree(CompilerInstance &ci, llvm::StringRef filename);
+
+void debugUnparseNoSema(CompilerInstance &ci, llvm::raw_ostream &out);
+
+void debugUnparseWithSymbols(CompilerInstance &ci);
+
+void debugUnparseWithModules(CompilerInstance &ci);
+
+void debugDumpParsingLog(CompilerInstance &ci);
+} // namespace Fortran::frontend
+
+#endif // FORTRAN_PARSER_ACTIONS_H_

flang/include/flang/Parser/options.h

@@ -0,0 +1,43 @@
+//===-- include/flang/Parser/options.h --------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_PARSER_OPTIONS_H_
+#define FORTRAN_PARSER_OPTIONS_H_
+
+#include "characters.h"
+#include "flang/Support/Fortran-features.h"
+
+#include <optional>
+#include <string>
+#include <vector>
+
+namespace Fortran::parser {
+
+struct Options {
+  Options() {}
+
+  using Predefinition = std::pair<std::string, std::optional<std::string>>;
+
+  bool isFixedForm{false};
+  int fixedFormColumns{72};
+  common::LanguageFeatureControl features;
+  std::vector<std::string> searchDirectories;
+  std::vector<std::string> intrinsicModuleDirectories;
+  std::vector<Predefinition> predefinitions;
+  bool instrumentedParse{false};
+  bool isModuleFile{false};
+  bool needProvenanceRangeToCharBlockMappings{false};
+  Fortran::parser::Encoding encoding{Fortran::parser::Encoding::UTF_8};
+  bool prescanAndReformat{false}; // -E
+  bool expandIncludeLinesInPreprocessedOutput{true};
+  bool showColors{false};
+};
+
+} // namespace Fortran::parser
+
+#endif // FORTRAN_PARSER_OPTIONS_H_

flang/include/flang/Parser/parsing.h

@@ -9,41 +9,18 @@
 #ifndef FORTRAN_PARSER_PARSING_H_
 #define FORTRAN_PARSER_PARSING_H_
 
-#include "characters.h"
 #include "instrumented-parser.h"
 #include "message.h"
+#include "options.h"
 #include "parse-tree.h"
 #include "provenance.h"
 #include "flang/Parser/preprocessor.h"
-#include "flang/Support/Fortran-features.h"
 #include "llvm/Support/raw_ostream.h"
 #include <optional>
 #include <string>
-#include <utility>
-#include <vector>
 
 namespace Fortran::parser {
 
-struct Options {
-  Options() {}
-
-  using Predefinition = std::pair<std::string, std::optional<std::string>>;
-
-  bool isFixedForm{false};
-  int fixedFormColumns{72};
-  common::LanguageFeatureControl features;
-  std::vector<std::string> searchDirectories;
-  std::vector<std::string> intrinsicModuleDirectories;
-  std::vector<Predefinition> predefinitions;
-  bool instrumentedParse{false};
-  bool isModuleFile{false};
-  bool needProvenanceRangeToCharBlockMappings{false};
-  Fortran::parser::Encoding encoding{Fortran::parser::Encoding::UTF_8};
-  bool prescanAndReformat{false}; // -E
-  bool expandIncludeLinesInPreprocessedOutput{true};
-  bool showColors{false};
-};
-
 class Parsing {
 public:
   explicit Parsing(AllCookedSources &);

flang/lib/Frontend/CMakeLists.txt

@@ -5,6 +5,7 @@ add_flang_library(flangFrontend
   CompilerInstance.cpp
   CompilerInvocation.cpp
   CodeGenOptions.cpp
+  ParserActions.cpp
   FrontendAction.cpp
   FrontendActions.cpp
   FrontendOptions.cpp

flang/lib/Frontend/FrontendAction.cpp

@@ -15,6 +15,7 @@
 #include "flang/Frontend/FrontendActions.h"
 #include "flang/Frontend/FrontendOptions.h"
 #include "flang/Frontend/FrontendPluginRegistry.h"
+#include "flang/Parser/parsing.h"
 #include "clang/Basic/DiagnosticFrontend.h"
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/VirtualFileSystem.h"