[clang][flang] Support -time in both clang and flang

The -time option prints timing information for the subcommands (compiler,
linker) in a format similar to that used by gcc/gfortran (we use more digits
of precision).

This partially addresses requests from #89888

Author: Tarun Prabhu

clang/include/clang/Driver/Options.td

@@ -5844,6 +5844,7 @@ def print_enabled_extensions : Flag<["-", "--"], "print-enabled-extensions">,
 def : Flag<["-"], "mcpu=help">, Alias<print_supported_cpus>;
 def : Flag<["-"], "mtune=help">, Alias<print_supported_cpus>;
 def time : Flag<["-"], "time">,
+  Visibility<[ClangOption, CLOption, DXCOption, FlangOption]>,
   HelpText<"Time individual commands">;
 def traditional_cpp : Flag<["-", "--"], "traditional-cpp">,
   Visibility<[ClangOption, CC1Option]>,

clang/lib/Driver/Compilation.cpp

@@ -21,6 +21,9 @@
 #include "llvm/Option/OptSpecifier.h"
 #include "llvm/Option/Option.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/TargetParser/Triple.h"
 #include <cassert>
@@ -194,11 +197,29 @@ int Compilation::ExecuteCommand(const Command &C,
   if (LogOnly)
     return 0;
 
+  // We don't use any timers or llvm::TimeGroup's because those are tied into
+  // the global static timer list which, in principle, could be cleared without
+  // us knowing about it.
+  llvm::TimeRecord StartTime;
+  if (getArgs().hasArg(options::OPT_time)) {
+    StartTime = llvm::TimeRecord::getCurrentTime(true);
+  }
+
   std::string Error;
   bool ExecutionFailed;
   int Res = C.Execute(Redirects, &Error, &ExecutionFailed);
   if (PostCallback)
     PostCallback(C, Res);
+
+  if (getArgs().hasArg(options::OPT_time)) {
+    llvm::TimeRecord Time = llvm::TimeRecord::getCurrentTime(false);
+    Time -= StartTime;
+    llvm::StringRef Name = llvm::sys::path::filename(C.getExecutable());
+    llvm::errs() << "# " << Name << " "
+                 << llvm::format("%0.5f", Time.getUserTime()) << " "
+                 << llvm::format("%0.5f", Time.getSystemTime()) << "\n";
+  }
+
   if (!Error.empty()) {
     assert(Res && "Error string set with 0 result code!");
     getDriver().Diag(diag::err_drv_command_failure) << Error;

clang/lib/Driver/Driver.cpp

@@ -1289,6 +1289,9 @@ Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
   // Ignore -pipe.
   Args.ClaimAllArgs(options::OPT_pipe);
 
+  // Ignore -time.
+  Args.ClaimAllArgs(options::OPT_time);
+
   // Extract -ccc args.
   //
   // FIXME: We need to figure out where this behavior should live. Most of it

clang/test/Driver/time.c

@@ -0,0 +1,24 @@
+// The -time option prints timing information for the various subcommands in a
+// format similar to that used by gcc. When compiling and linking, this will
+// include the time to call clang-${LLVM_VERSION_MAJOR} and the linker. Since
+// the name of the linker could vary across platforms, and name of the compiler
+// could be something different, just check that whatever is printed to stderr
+// looks like timing information.
+
+// RUN: %clang -time -c -O3 -o /dev/null %s 2>&1 \
+// RUN:     | FileCheck %s --check-prefix=COMPILE-ONLY
+// RUN: %clang -time -S -emit-llvm -O3 -o /dev/null %s 2>&1 \
+// RUN:     | FileCheck %s --check-prefix=COMPILE-ONLY
+// RUN: %clang -time -S -O3 -o /dev/null %s 2>&1 \
+// RUN:     | FileCheck %s --check-prefix=COMPILE-ONLY
+// RUN: %clang -time -O3 -o /dev/null %s 2>&1 \
+// RUN:     | FileCheck %s --check-prefix=COMPILE-AND-LINK
+
+// COMPILE-ONLY: # {{.+}} {{[0-9]+(.[0-9]+)?}} {{[0-9]+(.[0-9]+)?}}
+
+// COMPILE-AND-LINK: # {{.+}} {{[0-9]+(.[0-9]+)?}} {{[0-9]+(.[0-9]+)?}}
+// COMPILE-AND-LINK: # {{.+}} {{[0-9]+(.[0-9]+)?}} {{[0-9]+(.[0-9]+)?}}
+
+int main() {
+  return 0;
+}

flang/test/Driver/time.f90

@@ -0,0 +1,22 @@
+! The -time option prints timing information for the various subcommands in a
+! format similar to that used by gfortran. When compiling and linking, this will
+! include the time to call flang-${LLVM_VERSION_MAJOR} and the linker. Since the
+! name of the linker could vary across platforms, and the flang name could also
+! potentially be something different, just check that whatever is printed to
+! stderr looks like timing information.
+
+! RUN: %flang -time -c -O3 -o /dev/null %s 2>&1 \
+! RUN:     | FileCheck %s --check-prefix=COMPILE-ONLY
+! RUN: %flang -time -S -emit-llvm -O3 -o /dev/null %s 2>&1 \
+! RUN:     | FileCheck %s --check-prefix=COMPILE-ONLY
+! RUN: %flang -time -S -O3 -o /dev/null %s 2>&1 \
+! RUN:     | FileCheck %s --check-prefix=COMPILE-ONLY
+! RUN: %flang -time -O3 -o /dev/null %s 2>&1 \
+! RUN:     | FileCheck %s --check-prefix=COMPILE-AND-LINK
+
+! COMPILE-ONLY: # {{.+}} {{[0-9]+(.[0-9]+)?}} {{[0-9]+(.[0-9]+)?}}
+
+! COMPILE-AND-LINK: # {{.+}} {{[0-9]+(.[0-9]+)?}} {{[0-9]+(.[0-9]+)?}}
+! COMPILE-AND-LINK: # {{.+}} {{[0-9]+(.[0-9]+)?}} {{[0-9]+(.[0-9]+)?}}
+
+end program