[PATCH] D84853: [flang] Make interactive behaviour more obvious

[Richard Barton via Phabricator via llvm-commits]

richard.barton.arm created this revision.
Herald added a reviewer: DavidTruby.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.
richard.barton.arm requested review of this revision.

When flang is invoked with no files it waits for input on stdin. Make it
print a message saying this to prevent the user being surprised.

[flang] Add details to --help screen on default behaviour

Add a usage string and a defaults section that clarifies:

- If no input files are given, f18 reads from stdin
- If no input files are given, f18 dumps the parse tree.
- The default behaviour is to exec F18_FC.
- The fefault F18_FC setting is 'gfortran'

Adds a simple regression test which tests the top and tail of the help
screen and the exit status.

[flang] Add -h as a synonym for help

As expected by user in http://lists.llvm.org/pipermail/flang-dev/2020-June/000404.html


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D84853

Files:
  flang/test/Driver/Inputs/hello.f90
  flang/test/Driver/help.f90
  flang/test/Driver/no_files.f90
  flang/tools/f18/f18.cpp


Index: flang/tools/f18/f18.cpp
===================================================================
--- flang/tools/f18/f18.cpp
+++ flang/tools/f18/f18.cpp
@@ -603,8 +603,21 @@
       driver.getSymbolsSources = true;
     } else if (arg == "-byteswapio") {
       driver.byteswapio = true; // TODO: Pass to lowering, generate call
-    } else if (arg == "-help" || arg == "--help" || arg == "-?") {
+    } else if (arg == "-h" || arg == "-help" || arg == "--help" || arg == "-?") {
       llvm::errs()
+          << "f18: LLVM Fortran compiler\n"
+          << "\n"
+          << "Usage: f18 [options] <input files>\n"
+          << "\n"
+          << "Defaults:\n"
+          << "  When invoked with input files, and no options to tell\n"
+          << "  it otherwise, f18 will unparse its input and pass that on to an\n"
+          << "  external compiler to continue the compilation.\n"
+          << "  The external compiler is specified by the F18_FC environment\n"
+          << "  variable. The default is 'gfortran'.\n"
+          << "  If invoked with no input files, f18 reads source code from\n"
+          << "  stdin and runs with -fdebug-measure-parse-tree -funparse.\n"
+          << "\n"
           << "f18 options:\n"
           << "  -Mfixed | -Mfree | -ffixed-form | -ffree-form   force the "
              "source form\n"
@@ -638,7 +651,8 @@
           << "  -fget-symbols-sources\n"
           << "  -v -c -o -I -D -U    have their usual meanings\n"
           << "  -help                print this again\n"
-          << "Other options are passed through to the compiler.\n";
+          << "Unrecognised options are passed through to the external compiler\n"
+          << "set by F18_FC (see defaults).\n";
       return exitStatus;
     } else if (arg == "-V") {
       llvm::errs() << "\nf18 compiler (under development)\n";
@@ -686,6 +700,8 @@
   if (!anyFiles) {
     driver.measureTree = true;
     driver.dumpUnparse = true;
+    llvm::outs() << "Enter Fortran source\n"
+      << "Use EOF character (^D) to end file\n";
     CompileFortran("-", options, driver, defaultKinds);
     return exitStatus;
   }
Index: flang/test/Driver/no_files.f90
===================================================================
--- /dev/null
+++ flang/test/Driver/no_files.f90
@@ -0,0 +1,10 @@
+! RUN: %f18 < %S/Inputs/hello.f90 | FileCheck %s
+
+
+! CHECK: Enter Fortran source
+! CHECK: Use EOF character (^D) to end file
+
+! CHECK: Parse tree comprises {{.*}} objects and occupies {{.*}} total bytes
+! CHECK: PROGRAM hello
+! CHECK:  WRITE (*, *) "hello world"
+! CHECK: END PROGRAM hello
Index: flang/test/Driver/help.f90
===================================================================
--- /dev/null
+++ flang/test/Driver/help.f90
@@ -0,0 +1,10 @@
+! RUN: %f18 -h 2>&1 | FileCheck %s
+! RUN: %f18 -help 2>&1 | FileCheck %s
+! RUN: %f18 --help 2>&1 | FileCheck %s
+! RUN: %f18 -? 2>&1 | FileCheck %s
+
+! CHECK: f18: LLVM Fortran compiler
+
+! CHECK:   -help                print this again
+! CHECK: Unrecognised options are passed through to the external compiler
+! CHECK: set by F18_FC (see defaults).
Index: flang/test/Driver/Inputs/hello.f90
===================================================================
--- /dev/null
+++ flang/test/Driver/Inputs/hello.f90
@@ -0,0 +1,3 @@
+program hello
+  write (*,*), "hello world" 
+end program hello


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D84853.281601.patch
Type: text/x-patch
Size: 3373 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20200729/ff3dfeb7/attachment.bin>