Updated -help message in clang-check.

[alexfh]

Summary

Provide more information on usage in -help

[klimek]

clang-check/ClangCheck.cpp

25 ↗

(On Diff #18)

I think especially with the upcoming patch to allow other build system integration, I'd rather not call this cmake-output-dir. I think build-path is better, and having an explanation that mentions CMake as an example.

[alexfh]

Addressed comments.

[alexfh]

clang-check/ClangCheck.cpp

25 ↗

(On Diff #18)

makes sense.
what about "If the path is\n"

"relative, the current working directory needs to be in the CMake source\n"	
"tree and the file must be in a subdirectory of the current working\n"	
"directory." part? can we make this eat any form of paths?

[alexfh]

Minor wording change

[alexfh]

Updated, resolved conflicts

ClangCheck.cpp

 //===- examples/Tooling/ClangCheck.cpp - Clang check tool -----------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 //  This file implements a clang-check tool that runs the
 //  clang::SyntaxOnlyAction over a number of translation units.
 //
-//  Usage:
-//  clang-check [-p <cmake-output-dir>] <file1> <file2> ...
-//
-//  Where <cmake-output-dir> is a CMake build directory in which a file named
-//  compile_commands.json exists (enable -DCMAKE_EXPORT_COMPILE_COMMANDS in
-//  CMake to get this output). If not provided, clang-check will search for this
-//  file in all of <file1>'s parent directories.
-//
-//  <file1> ... specify the paths of files in the CMake source tree. This path
-//  is looked up in the compile command database. If the path of a file is
-//  absolute, it needs to point into CMake's source tree. If the path is
-//  relative, the current working directory needs to be in the CMake source
-//  tree and the file must be in a subdirectory of the current working
-//  directory. "./" prefixes in the relative files will be automatically
-//  removed, but the rest of a relative path must be a suffix of a path in
-//  the compile command line database.
-//
-//  For example, to use clang-check on all files in a subtree of the source
-//  tree, use:
-//
-//    /path/in/subtree $ find . -name '*.cpp'| xargs clang-check
-//
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/CommandLine.h"
 #include "clang/Frontend/FrontendActions.h"
 #include "clang/Tooling/CompilationDatabase.h"
 #include "clang/Tooling/Tooling.h"
 
 using namespace clang::tooling;
 using namespace llvm;
 
 cl::opt<std::string> BuildPath(
   "p",
   cl::desc("<build-path>"),
   cl::Optional);
 
 cl::list<std::string> SourcePaths(
   cl::Positional,
   cl::desc("<source0> [... <sourceN>]"),
   cl::OneOrMore);
 
+static cl::extrahelp MoreHelp(
+    "\n"
+    "<build-path> is used to read a compile command database.\n"
+    "\n"
+    "For example, it can be a CMake build directory in which a file named\n"
+    "compile_commands.json exists (use -DCMAKE_EXPORT_COMPILE_COMMANDS=ON\n"
+    "CMake option to get this output). When no build path is specified,\n"
+    "clang-check will attempt to locate it automatically using all parent\n"
+    "paths of the first input file.\n"
+    "\n"
+    "<source0> ... specify the paths of source files. These paths are looked\n"
+    "up in the compile command database. If the path of a file is absolute,\n"
+    "it needs to point into CMake's source tree. If the path is relative,\n"
+    "the current working directory needs to be in the CMake source tree and\n"
+    "the file must be in a subdirectory of the current working directory.\n"
+    "\"./\" prefixes in the relative files will be automatically removed,\n"
+    "but the rest of a relative path must be a suffix of a path in the\n"
+    "compile command database.\n"
+    "\n"
+    "For example, to use clang-check on all files in a subtree of the source\n"
+    "tree, use:\n"
+    "\n"
+    "  find path/in/subtree -name '*.cpp'|xargs clang-check\n"
+    "\n"
+    "or using a specific build path:\n"
+    "\n"
+    "  find path/in/subtree -name '*.cpp'|xargs clang-check -p build/path\n"
+    "\n"
+    "Note, that path/in/subtree and current directory should follow the\n"
+    "rules described above.\n"
+    "\n"
+);
+
 int main(int argc, const char **argv) {
   llvm::OwningPtr<CompilationDatabase> Compilations(
     FixedCompilationDatabase::loadFromCommandLine(argc, argv));
   cl::ParseCommandLineOptions(argc, argv);
   if (!Compilations) {
     std::string ErrorMessage;
     if (!BuildPath.empty()) {
       Compilations.reset(