[flang][Driver] Preliminary support for -ftime-report

clang/include/clang/Driver/Options.td

@@ -4108,7 +4108,7 @@ defm ms_tls_guards : BoolFOption<"ms-tls-guards",
           "Do not emit code to perform on-demand initialization of thread-local variables">,
   PosFlag<SetTrue>>;
 def ftime_report : Flag<["-"], "ftime-report">, Group<f_Group>,
-  Visibility<[ClangOption, CC1Option]>,
+  Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
   MarshallingInfoFlag<CodeGenOpts<"TimePasses">>;
 def ftime_report_EQ: Joined<["-"], "ftime-report=">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option]>, Values<"per-pass,per-pass-run">,

clang/lib/Driver/ToolChains/Flang.cpp

@@ -150,10 +150,12 @@ void Flang::addCodegenOptions(const ArgList &Args,
   if (shouldLoopVersion(Args))
     CmdArgs.push_back("-fversion-loops-for-stride");
 
-  Args.addAllArgs(CmdArgs, {options::OPT_flang_experimental_hlfir,
-                            options::OPT_flang_deprecated_no_hlfir,
-                            options::OPT_fno_ppc_native_vec_elem_order,
-                            options::OPT_fppc_native_vec_elem_order});
+  Args.addAllArgs(CmdArgs,
+                  {options::OPT_flang_experimental_hlfir,
+                   options::OPT_flang_deprecated_no_hlfir,
+                   options::OPT_fno_ppc_native_vec_elem_order,
+                   options::OPT_fppc_native_vec_elem_order,
+                   options::OPT_ftime_report, options::OPT_ftime_report_EQ});
 }
 
 void Flang::addPicOptions(const ArgList &Args, ArgStringList &CmdArgs) const {

flang/include/flang/Frontend/CompilerInstance.h

@@ -20,6 +20,7 @@
 #include "flang/Parser/provenance.h"
 #include "flang/Semantics/runtime-type-info.h"
 #include "flang/Semantics/semantics.h"
+#include "flang/Support/StringOstream.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetMachine.h"
 
@@ -85,6 +86,27 @@ class CompilerInstance {
   /// facilitate this. It is optional and will normally be just a nullptr.
   std::unique_ptr<llvm::raw_pwrite_stream> outputStream;
 
+  /// @name Timing
+  /// Objects needed when timing is enabled.
+  /// @{
+  /// The timing manager.
+  mlir::DefaultTimingManager timingMgr;
+
+  /// The root of the timingScope. This will be reset in @ref executeAction if
+  /// timers have been enabled.
+  mlir::TimingScope timingScopeRoot;
+
+  /// @name Timing stream
+  /// The output streams to capture the timing. Three different streams are
+  /// needed because the timing classes all work slightly differently. We create
+  /// these streams so we have control over when and how the timing is
+  /// displayed. Otherwise, the timing is only displayed when the corresponding
+  /// managers/timers go out of scope.
+  std::unique_ptr<Fortran::support::string_ostream> timingStreamMLIR;
+  std::unique_ptr<Fortran::support::string_ostream> timingStreamLLVM;
+  std::unique_ptr<Fortran::support::string_ostream> timingStreamCodeGen;
+  /// @}
+
 public:
   explicit CompilerInstance();
 
@@ -254,6 +276,42 @@ class CompilerInstance {
   /// Produces the string which represents target feature
   std::string getTargetFeatures();
 
+  /// {
+  /// @name Timing
+  /// @{
+  bool isTimingEnabled() const { return timingMgr.isEnabled(); }
+
+  mlir::DefaultTimingManager &getTimingManager() { return timingMgr; }
+  const mlir::DefaultTimingManager &getTimingManager() const {
+    return timingMgr;
+  }
+
+  mlir::TimingScope &getTimingScopeRoot() { return timingScopeRoot; }
+  const mlir::TimingScope &getTimingScopeRoot() const {
+    return timingScopeRoot;
+  }
+
+  /// Get the timing stream for the MLIR pass manager.
+  llvm::raw_ostream &getTimingStreamMLIR() {
+    assert(timingStreamMLIR && "Timing stream for MLIR was not set");
+    return *timingStreamMLIR;
+  }
+
+  /// Get the timing stream for the new LLVM pass manager.
+  llvm::raw_ostream &getTimingStreamLLVM() {
+    assert(timingStreamLLVM && "Timing stream for LLVM was not set");
+    return *timingStreamLLVM;
+  }
+
+  /// Get the timing stream fro the legacy LLVM pass manager.
+  /// NOTE: If the codegen is updated to use the new pass manager, this should
+  /// no longer be needed.
+  llvm::raw_ostream &getTimingStreamCodeGen() {
+    assert(timingStreamCodeGen && "Timing stream for codegen was not set");
+    return *timingStreamCodeGen;
+  }
+  /// @}
+
 private:
   /// Create a new output file
   ///

flang/include/flang/Frontend/CompilerInvocation.h

@@ -21,6 +21,7 @@
 #include "flang/Lower/LoweringOptions.h"
 #include "flang/Parser/parsing.h"
 #include "flang/Semantics/semantics.h"
+#include "mlir/Support/Timing.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "llvm/Option/ArgList.h"
@@ -143,6 +144,10 @@ class CompilerInvocation : public CompilerInvocationBase {
       },
   };
 
+  /// Whether to time the invocation. Set when -ftime-report or -ftime-report=
+  /// is enabled.
+  bool enableTimers;
+
 public:
   CompilerInvocation() = default;
 
@@ -222,6 +227,8 @@ class CompilerInvocation : public CompilerInvocationBase {
     return defaultKinds;
   }
 
+  bool getEnableTimers() const { return enableTimers; }
+
   /// Create a compiler invocation from a list of input options.
   /// \returns true on success.
   /// \returns false if an error was encountered while parsing the arguments

flang/include/flang/Support/StringOstream.h

@@ -0,0 +1,32 @@
+//===-- CompilerInstance.h - Flang Compiler Instance ------------*- 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_SUPPORT_STRINGOSTREAM_H
+#define FORTRAN_SUPPORT_STRINGOSTREAM_H
+
+#include <llvm/Support/raw_ostream.h>
+
+namespace Fortran::support {
+
+/// Helper class to maintain both the an llvm::raw_string_ostream object and
+/// its associated buffer.
+class string_ostream : public llvm::raw_string_ostream {
+private:
+  std::string buf;
+
+public:
+  string_ostream() : llvm::raw_string_ostream(buf) {}
+};
+
+} // namespace Fortran::support
+
+#endif // FORTRAN_SUPPORT_STRINGOSTREAM_H

flang/include/flang/Support/Timing.h

@@ -0,0 +1,27 @@
+//===- Timing.h - Execution time measurement facilities ---------*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Facilities to measure and provide statistics on execution time.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_SUPPORT_TIMING_H
+#define FORTRAN_SUPPORT_TIMING_H
+
+#include "mlir/Support/Timing.h"
+
+namespace Fortran::support {
+
+/// Create a strategy to render the captured times in plain text. This is
+/// intended to be passed to a TimingManager.
+std::unique_ptr<mlir::OutputStrategy> createTimingFormatterText(
+    llvm::raw_ostream &os);
+
+} // namespace Fortran::support
+
+#endif // FORTRAN_SUPPORT_TIMING_H

flang/lib/CMakeLists.txt

@@ -4,6 +4,7 @@ add_subdirectory(Decimal)
 add_subdirectory(Lower)
 add_subdirectory(Parser)
 add_subdirectory(Semantics)
+add_subdirectory(Support)
 add_subdirectory(Frontend)
 add_subdirectory(FrontendTool)
 

flang/lib/Frontend/CMakeLists.txt

@@ -29,6 +29,7 @@ add_flang_library(flangFrontend
   FortranEvaluate
   FortranCommon
   FortranLower
+  FortranSupport
   FIRDialect
   FIRDialectSupport
   FIRSupport

flang/lib/Frontend/CompilerInstance.cpp

@@ -17,9 +17,12 @@
 #include "flang/Parser/parsing.h"
 #include "flang/Parser/provenance.h"
 #include "flang/Semantics/semantics.h"
+#include "flang/Support/Timing.h"
+#include "mlir/Support/RawOstreamExtras.h"
 #include "clang/Basic/DiagnosticFrontend.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/MC/TargetRegistry.h"
+#include "llvm/Pass.h"
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FileSystem.h"
@@ -147,7 +150,7 @@ void CompilerInstance::clearOutputFiles(bool eraseFiles) {
 }
 
 bool CompilerInstance::executeAction(FrontendAction &act) {
-  auto &invoc = this->getInvocation();
+  CompilerInvocation &invoc = this->getInvocation();
 
   llvm::Triple targetTriple{llvm::Triple(invoc.getTargetOpts().triple)};
   if (targetTriple.getArch() == llvm::Triple::ArchType::x86_64) {
@@ -167,6 +170,25 @@ bool CompilerInstance::executeAction(FrontendAction &act) {
   // Set options controlling lowering to FIR.
   invoc.setLoweringOptions();
 
+  if (invoc.getEnableTimers()) {
+    llvm::TimePassesIsEnabled = true;
+
+    timingStreamMLIR = std::make_unique<Fortran::support::string_ostream>();
+    timingStreamLLVM = std::make_unique<Fortran::support::string_ostream>();
+    timingStreamCodeGen = std::make_unique<Fortran::support::string_ostream>();
+
+    timingMgr.setEnabled(true);
+    timingMgr.setDisplayMode(mlir::DefaultTimingManager::DisplayMode::Tree);
+    timingMgr.setOutput(
+        Fortran::support::createTimingFormatterText(*timingStreamMLIR));
+
+    // Creating a new TimingScope will automatically start the timer. Since this
+    // is the top-level timer, this is ok because it will end up capturing the
+    // time for all the bookkeeping and other tasks that take place between
+    // parsing, lowering etc. for which finer-grained timers will be created.
+    timingScopeRoot = timingMgr.getRootScope();
+  }
+
   // Run the frontend action `act` for every input file.
   for (const FrontendInputFile &fif : getFrontendOpts().inputs) {
     if (act.beginSourceFile(*this, fif)) {
@@ -176,6 +198,34 @@ bool CompilerInstance::executeAction(FrontendAction &act) {
       act.endSourceFile();
     }
   }
+
+  if (timingMgr.isEnabled()) {
+    timingScopeRoot.stop();
+
+    // Write the timings to the associated output stream and clear all timers.
+    // We need to provide another stream because the TimingManager will attempt
+    // to print in its destructor even if it has been cleared. By the time that
+    // destructor runs, the output streams will have been destroyed, so give it
+    // a null stream.
+    timingMgr.print();
+    timingMgr.setOutput(
+        Fortran::support::createTimingFormatterText(mlir::thread_safe_nulls()));
+
+    // This prints the timings in "reverse" order, starting from code
+    // generation, followed by LLVM-IR optimizations, then MLIR optimizations
+    // and transformations and the frontend. If any of the steps are disabled,
+    // for instance because code generation was not performed, the strings
+    // will be empty.
+    if (!timingStreamCodeGen->str().empty())
+      llvm::errs() << timingStreamCodeGen->str() << "\n";
+
+    if (!timingStreamLLVM->str().empty())
+      llvm::errs() << timingStreamLLVM->str() << "\n";
+
+    if (!timingStreamMLIR->str().empty())
+      llvm::errs() << timingStreamMLIR->str() << "\n";
+  }
+
   return !getDiagnostics().getClient()->getNumErrors();
 }
 

flang/lib/Frontend/CompilerInvocation.cpp

@@ -1436,6 +1436,10 @@ bool CompilerInvocation::createFromArgs(
     }
   }
 
+  // Process the timing-related options.
+  if (args.hasArg(clang::driver::options::OPT_ftime_report))
+    invoc.enableTimers = true;
+
   invoc.setArgv0(argv0);
 
   return success;