Improve error messages and reporting in GN

tools/gn/variables.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/variables.h"
 
 namespace variables {
 
 // Built-in variables ----------------------------------------------------------
 
@@ skipping 278 matching lines @@
     "\n"
     "  For action and action_foreach targets, args is the list of arguments\n"
     "  to pass to the script. Typically you would use source expansion (see\n"
     "  \"gn help source_expansion\") to insert the source file names.\n"
     "\n"
     "  See also \"gn help action\" and \"gn help action_foreach\".\n";
 
 const char kCflags[] = "cflags";
 const char kCflags_HelpShort[] =
     "cflags: [string list] Flags passed to all C compiler variants.";
-// Avoid writing long help for each variant.
-#define COMMON_FLAGS_HELP \
-    "\n"\
-    "  Flags are never quoted. If your flag includes a string that must be\n"\
-    "  quoted, you must do it yourself. This also means that you can\n"\
-    "  specify more than one flag in a string if necessary (\"--foo --bar\")\n"\
-    "  and have them be seen as separate by the tool.\n"
 const char kCommonCflagsHelp[] =
     "cflags*: Flags passed to the C compiler.\n"
     "\n"
     "  A list of strings.\n"
     "\n"
     "  \"cflags\" are passed to all invocations of the C, C++, Objective C,\n"
     "  and Objective C++ compilers.\n"
     "\n"
     "  To target one of these variants individually, use \"cflags_c\",\n"
     "  \"cflags_cc\", \"cflags_objc\", and \"cflags_objcc\", respectively.\n"
     "  These variant-specific versions will be appended to the \"cflags\".\n"
-    COMMON_FLAGS_HELP
     COMMON_ORDERING_HELP;
 const char* kCflags_Help = kCommonCflagsHelp;
 
 const char kCflagsC[] = "cflags_c";
 const char kCflagsC_HelpShort[] =
     "cflags_c: [string list] Flags passed to the C compiler.";
 const char* kCflagsC_Help = kCommonCflagsHelp;
 
 const char kCflagsCC[] = "cflags_cc";
 const char kCflagsCC_HelpShort[] =
@@ skipping 224 matching lines @@
     "\n"
     "  A list of strings.\n"
     "\n"
     "  These flags are passed on the command-line to the linker and generally\n"
     "  specify various linking options. Most targets will not need these and\n"
     "  will use \"libs\" and \"lib_dirs\" instead.\n"
     "\n"
     "  ldflags are NOT pushed to dependents, so applying ldflags to source\n"
     "  sets or static libraries will be a no-op. If you want to apply ldflags\n"
     "  to dependent targets, put them in a config and set it in the\n"
-    "  all_dependent_configs or direct_dependent_configs.\n"
-    COMMON_FLAGS_HELP;
+    "  all_dependent_configs or direct_dependent_configs.\n";
 
 #define COMMON_LIB_INHERITANCE_HELP \
     "\n" \
     "  libs and lib_dirs work differently than other flags in two respects.\n" \
     "  First, then are inherited across static library boundaries until a\n" \
     "  shared library or executable target is reached. Second, they are\n" \
     "  uniquified so each one is only passed once (the first instance of it\n" \
     "  will be the one used).\n"
 
 const char kLibDirs[] = "lib_dirs";
@@ skipping 323 matching lines @@
     INSERT_VARIABLE(SourcePrereqs)
     INSERT_VARIABLE(Sources)
     INSERT_VARIABLE(Visibility)
   }
   return info_map;
 }
 
 #undef INSERT_VARIABLE
 
 }  // namespace variables