[docs] Add help text and refine grouping for various options.

Also accept -G= (and -msmall-data-threshold=) as an alias for -G on MIPS as well as Hexagon.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@293254 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 210 insertions, 168 deletions

diff --git a/docs/ClangCommandLineReference.rst b/docs/ClangCommandLineReference.rst
index e39d983954..7d4cc5d2c1 100644
--- a/docs/ClangCommandLineReference.rst
+++ b/docs/ClangCommandLineReference.rst
@@ -18,30 +18,14 @@ GCC-compatible ``clang`` and ``clang++`` drivers.
 
 
 .. program:: clang
-.. option:: -A<arg>, --assert <arg>, --assert=<arg>
-
-.. option:: -B<arg>, --prefix <arg>, --prefix=<arg>
+.. option:: -B<dir>, --prefix <arg>, --prefix=<arg>
 
-.. option:: -C, --comments
-
-.. option:: -CC, --comments-in-macros
+Add <dir> to search path for binaries and object files used implicitly
 
 .. option:: -F<arg>
 
 Add directory to framework include search path
 
-.. option:: -G<arg>
-
-.. program:: clang1
-.. option:: -G=<arg>
-.. program:: clang
-
-.. option:: -H, --trace-includes
-
-Show header includes and nesting depth
-
-.. option:: -Mach
-
 .. option:: -ObjC
 
 Treat source input files as Objective-C inputs
@@ -52,14 +36,6 @@ Treat source input files as Objective-C inputs
 
 Treat source input files as Objective-C++ inputs
 
-.. option:: -P, --no-line-commands
-
-Disable linemarker output in -E mode
-
-.. option:: -Q
-
-.. option:: -Qn
-
 .. option:: -Qunused-arguments
 
 Don't emit warning for unused driver arguments
@@ -70,26 +46,8 @@ Pass the comma separated arguments in <arg> to the assembler
 
 .. option:: -Wlarge-by-value-copy=<arg>
 
-.. option:: -Wp,<arg>,<arg2>...
-
-Pass the comma separated arguments in <arg> to the preprocessor
-
-.. option:: -X<arg>
-
-.. program:: clang1
-.. option:: -X
-.. program:: clang
-
-.. option:: -Xanalyzer <arg>
-
-Pass <arg> to the static analyzer
-
 .. option:: -Xarch\_<arg1> <arg2>
 
-.. option:: -Xassembler <arg>
-
-Pass <arg> to the assembler
-
 .. option:: -Xcuda-fatbinary <arg>
 
 Pass <arg> to fatbinary invocation
@@ -98,10 +56,6 @@ Pass <arg> to fatbinary invocation
 
 Pass <arg> to the ptxas assembler
 
-.. option:: -Xpreprocessor <arg>
-
-Pass <arg> to the preprocessor
-
 .. option:: -Z<arg>
 
 .. option:: -a<arg>, --profile-blocks
@@ -150,10 +104,6 @@ Output path for the plist report
 .. option:: -bundle\_loader <arg>
 .. program:: clang
 
-.. option:: -c, --compile
-
-Only run preprocess, compile, and assemble steps
-
 .. option:: -client\_name<arg>
 
 .. option:: -compatibility\_version<arg>
@@ -650,6 +600,10 @@ Only run the preprocessor
 
 Only run preprocess and compilation steps
 
+.. option:: -c, --compile
+
+Only run preprocess, compile, and assemble steps
+
 .. option:: -emit-llvm
 
 Use the LLVM representation for assembler and object files
@@ -678,9 +632,9 @@ Compilation flags
 Flags controlling the behavior of Clang during compilation. These flags have
 no effect during actions that do not perform compilation.
 
-.. option:: -D<arg>, --define-macro <arg>, --define-macro=<arg>
+.. option:: -Xassembler <arg>
 
-.. option:: -U<arg>, --undefine-macro <arg>, --undefine-macro=<arg>
+Pass <arg> to the assembler
 
 .. option:: -Xclang <arg>
 
@@ -810,17 +764,56 @@ Turn on runtime checks for various forms of undefined or suspicious behavior. Se
 
 Language standard to compile for
 
+Preprocessor flags
+~~~~~~~~~~~~~~~~~~
+
+Flags controlling the behavior of the Clang preprocessor.
+
+.. option:: -C, --comments
+
+Include comments in preprocessed output
+
+.. option:: -CC, --comments-in-macros
+
+Include comments from within macros in preprocessed output
+
+.. option:: -D<macro>=<value>, --define-macro <arg>, --define-macro=<arg>
+
+Define <macro> to <value> (or 1 if <value> omitted)
+
+.. option:: -H, --trace-includes
+
+Show header includes and nesting depth
+
+.. option:: -P, --no-line-commands
+
+Disable linemarker output in -E mode
+
+.. option:: -U<macro>, --undefine-macro <arg>, --undefine-macro=<arg>
+
+Undefine macro <macro>
+
+.. option:: -Wp,<arg>,<arg2>...
+
+Pass the comma separated arguments in <arg> to the preprocessor
+
+.. option:: -Xpreprocessor <arg>
+
+Pass <arg> to the preprocessor
+
 Include path management
-~~~~~~~~~~~~~~~~~~~~~~~
+-----------------------
 
 Flags controlling how ``#include``\s are resolved to files.
 
-.. option:: -I<arg>, --include-directory <arg>, --include-directory=<arg>
+.. option:: -I<dir>, --include-directory <arg>, --include-directory=<arg>
 
 Add directory to include search path
 
 .. option:: -I-, --include-barrier
 
+Restrict all prior -I flags to double-quoted inclusion and remove current directory from include path
+
 .. option:: --cuda-path=<arg>
 
 CUDA installation path
@@ -936,7 +929,7 @@ Path to ptxas (used for compiling CUDA code)
 Treat all #include paths starting with <prefix> as including a system header.
 
 Dependency file generation
-~~~~~~~~~~~~~~~~~~~~~~~~~~
+--------------------------
 
 Flags controlling generation of a dependency file for ``make``-like build
 systems.
@@ -986,7 +979,7 @@ Specify name of main file output in depfile
 Use NMake/Jom format for the depfile
 
 Dumping preprocessor state
-~~~~~~~~~~~~~~~~~~~~~~~~~~
+--------------------------
 
 Flags allowing the state of the preprocessor to be dumped in various ways.
 
@@ -1036,18 +1029,12 @@ Report transformations performed by optimization passes whose name matches the g
 
 Enable the specified warning
 
-.. option:: -WCL4
-
-.. option:: -Wall, --all-warnings
-
 .. option:: -Wdeprecated, -Wno-deprecated
 
-.. option:: -Wextra
+Enable warnings for deprecated constructs and define \_\_DEPRECATED
 
 .. option:: -Wnonportable-cfstrings<arg>, -Wno-nonportable-cfstrings<arg>
 
-.. option:: -Wwrite-strings, -Wno-write-strings
-
 Target-independent compilation options
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 .. option:: -Wframe-larger-than=<arg>
@@ -1852,6 +1839,10 @@ OpenCL only. Allow unsafe floating-point optimizations.  Also implies -cl-no-sig
 
 Target-dependent compilation options
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.. option:: -G<size>, -G=<arg>, -msmall-data-threshold=<arg>
+
+Put objects of at most <size> bytes into small data section (MIPS / Hexagon)
+
 .. option:: -m16
 
 .. option:: -m32
@@ -1998,8 +1989,6 @@ Make StdCall calling convention the default
 
 .. option:: -msingle-float
 
-.. option:: -msmall-data-threshold=<arg>
-
 .. option:: -msoft-float, -mno-soft-float
 
 Use software floating point
@@ -2245,10 +2234,6 @@ Flags controlling how much optimization should be performed.
 
 .. option:: -O<arg>, -O (equivalent to -O2), --optimize, --optimize=<arg>
 
-.. option:: -O0
-
-.. option:: -O4
-
 .. option:: -Ofast<arg>
 
 Debug information generation
@@ -2329,57 +2314,14 @@ Debug information flags
 
 .. option:: -gstrict-dwarf, -gno-strict-dwarf
 
-Linker flags
-============
-Flags that are passed on to the linker
-
-.. option:: -L<arg>, --library-directory <arg>, --library-directory=<arg>
-
-.. option:: -T<arg>
-
-.. option:: -Tbss<arg>
+Static analyzer flags
+=====================
 
-.. option:: -Tdata<arg>
+Flags controlling the behavior of the Clang Static Analyzer.
 
-.. option:: -Ttext<arg>
-
-.. option:: -Wl,<arg>,<arg2>...
-
-Pass the comma separated arguments in <arg> to the linker
-
-.. option:: -Xlinker <arg>, --for-linker <arg>, --for-linker=<arg>
-
-Pass <arg> to the linker
-
-.. program:: clang1
-.. option:: -Z
-.. program:: clang
-
-.. option:: -e<arg>, --entry
-
-.. option:: -filelist <arg>
-
-.. option:: -l<arg>
-
-.. option:: -r
-
-.. option:: -rpath <arg>
-
-.. option:: -s
-
-.. option:: -t
-
-.. option:: -u<arg>, --force-link <arg>, --force-link=<arg>
-
-.. option:: -undef
-
-undef all system defines
-
-.. option:: -undefined<arg>, --no-undefined
-
-.. option:: -z <arg>
+.. option:: -Xanalyzer <arg>
 
-Pass -z <arg> to the linker
+Pass <arg> to the static analyzer
 
 Fortran compilation flags
 =========================
@@ -2387,6 +2329,8 @@ Fortran compilation flags
 Flags that will be passed onto the ``gfortran`` compiler when Clang is given
 a Fortran input.
 
+.. option:: -A<arg>, --assert <arg>, --assert=<arg>
+
 .. option:: -A-<arg>
 
 .. option:: -J<arg>
@@ -2521,3 +2465,69 @@ a Fortran input.
 
 .. option:: -static-libgfortran
 
+Linker flags
+============
+Flags that are passed on to the linker
+
+.. option:: -L<dir>, --library-directory <arg>, --library-directory=<arg>
+
+Add directory to library search path
+
+.. option:: -Mach
+
+.. option:: -T<script>
+
+Specify <script> as linker script
+
+.. option:: -Tbss<addr
+
+Set starting address of BSS to <addr>
+
+.. option:: -Tdata<addr
+
+Set starting address of BSS to <addr>
+
+.. option:: -Ttext<addr
+
+Set starting address of BSS to <addr>
+
+.. option:: -Wl,<arg>,<arg2>...
+
+Pass the comma separated arguments in <arg> to the linker
+
+.. option:: -X
+
+.. option:: -Xlinker <arg>, --for-linker <arg>, --for-linker=<arg>
+
+Pass <arg> to the linker
+
+.. program:: clang1
+.. option:: -Z
+.. program:: clang
+
+.. option:: -e<arg>, --entry
+
+.. option:: -filelist <arg>
+
+.. option:: -l<arg>
+
+.. option:: -r
+
+.. option:: -rpath <arg>
+
+.. option:: -s
+
+.. option:: -t
+
+.. option:: -u<arg>, --force-link <arg>, --force-link=<arg>
+
+.. option:: -undef
+
+undef all system defines
+
+.. option:: -undefined<arg>, --no-undefined
+
+.. option:: -z <arg>
+
+Pass -z <arg> to the linker
+
diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 45ec4eafc7..b3fd51e25d 100644
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -63,6 +63,10 @@ class DocBrief<code descr> { code DocBrief = descr; }
 // documentation.
 class DocFlatten { bit DocFlatten = 1; }
 
+// Indicates that this warning is ignored, but accepted with a warning for
+// GCC compatibility.
+class IgnoredGCCCompat : Flags<[HelpHidden]> {}
+
 /////////
 // Groups
 
@@ -76,7 +80,12 @@ def CompileOnly_Group : OptionGroup<"<CompileOnly group>">,
 Flags controlling the behavior of Clang during compilation. These flags have
 no effect during actions that do not perform compilation.}]>;
 
-def IncludePath_Group : OptionGroup<"<I/i group>">, Group<CompileOnly_Group>,
+def Preprocessor_Group : OptionGroup<"<Preprocessor group>">,
+                         Group<CompileOnly_Group>,
+                         DocName<"Preprocessor flags">, DocBrief<[{
+Flags controlling the behavior of the Clang preprocessor.}]>;
+
+def IncludePath_Group : OptionGroup<"<I/i group>">, Group<Preprocessor_Group>,
                         DocName<"Include path management">,
                         DocBrief<[{
 Flags controlling how ``#include``\s are resolved to files.}]>;
@@ -85,12 +94,12 @@ def I_Group : OptionGroup<"<I group>">, Group<IncludePath_Group>, DocFlatten;
 def i_Group : OptionGroup<"<i group>">, Group<IncludePath_Group>, DocFlatten;
 def clang_i_Group : OptionGroup<"<clang i group>">, Group<i_Group>, DocFlatten;
 
-def M_Group : OptionGroup<"<M group>">, Group<CompileOnly_Group>,
+def M_Group : OptionGroup<"<M group>">, Group<Preprocessor_Group>,
               DocName<"Dependency file generation">, DocBrief<[{
 Flags controlling generation of a dependency file for ``make``-like build
 systems.}]>;
 
-def d_Group : OptionGroup<"<d group>">, Group<CompileOnly_Group>,
+def d_Group : OptionGroup<"<d group>">, Group<Preprocessor_Group>,
               DocName<"Dumping preprocessor state">, DocBrief<[{
 Flags allowing the state of the preprocessor to be dumped in various ways.}]>;
 
@@ -159,6 +168,17 @@ def gTune_Group : OptionGroup<"<gTune group>">, Group<g_Group>,
 def g_flags_Group : OptionGroup<"<g flags group>">, Group<DebugInfo_Group>,
                     DocName<"Debug information flags">;
 
+def StaticAnalyzer_Group : OptionGroup<"<Static analyzer group>">,
+                           DocName<"Static analyzer flags">, DocBrief<[{
+Flags controlling the behavior of the Clang Static Analyzer.}]>;
+
+// gfortran options that we recognize in the driver and pass along when
+// invoking GCC to compile Fortran code.
+def gfortran_Group : OptionGroup<"<gfortran group>">,
+                     DocName<"Fortran compilation flags">, DocBrief<[{
+Flags that will be passed onto the ``gfortran`` compiler when Clang is given
+a Fortran input.}]>;
+
 def Link_Group : OptionGroup<"<T/e/s/t/u group>">, DocName<"Linker flags">,
                  DocBrief<[{Flags that are passed on to the linker}]>;
 def T_Group : OptionGroup<"<T group>">, Group<Link_Group>, DocFlatten;
@@ -297,23 +317,34 @@ def _HASH_HASH_HASH : Flag<["-"], "###">, Flags<[DriverOption, CoreOption]>,
     HelpText<"Print (but do not run) the commands to run for this compilation">;
 def _DASH_DASH : Option<["--"], "", KIND_REMAINING_ARGS>,
     Flags<[DriverOption, CoreOption]>;
-def A : JoinedOrSeparate<["-"], "A">, Flags<[RenderJoined]>;
-def B : JoinedOrSeparate<["-"], "B">;
-def CC : Flag<["-"], "CC">, Flags<[CC1Option]>;
-def C : Flag<["-"], "C">, Flags<[CC1Option]>;
-def D : JoinedOrSeparate<["-"], "D">, Group<CompileOnly_Group>, Flags<[CC1Option]>;
+def A : JoinedOrSeparate<["-"], "A">, Flags<[RenderJoined]>, Group<gfortran_Group>;
+def B : JoinedOrSeparate<["-"], "B">, MetaVarName<"<dir>">,
+    HelpText<"Add <dir> to search path for binaries and object files used implicitly">;
+def CC : Flag<["-"], "CC">, Flags<[CC1Option]>, Group<Preprocessor_Group>,
+    HelpText<"Include comments from within macros in preprocessed output">;
+def C : Flag<["-"], "C">, Flags<[CC1Option]>, Group<Preprocessor_Group>,
+    HelpText<"Include comments in preprocessed output">;
+def D : JoinedOrSeparate<["-"], "D">, Group<Preprocessor_Group>,
+    Flags<[CC1Option]>, MetaVarName<"<macro>=<value>">,
+    HelpText<"Define <macro> to <value> (or 1 if <value> omitted)">;
 def E : Flag<["-"], "E">, Flags<[DriverOption,CC1Option]>, Group<Action_Group>,
-  HelpText<"Only run the preprocessor">;
+    HelpText<"Only run the preprocessor">;
 def F : JoinedOrSeparate<["-"], "F">, Flags<[RenderJoined,CC1Option]>,
     HelpText<"Add directory to framework include search path">;
-def G : JoinedOrSeparate<["-"], "G">, Flags<[DriverOption]>;
-def G_EQ : Joined<["-"], "G=">, Flags<[DriverOption]>;
-def H : Flag<["-"], "H">, Flags<[CC1Option]>,
+def G : JoinedOrSeparate<["-"], "G">, Flags<[DriverOption]>, Group<m_Group>,
+    MetaVarName<"<size>">, HelpText<"Put objects of at most <size> bytes "
+    "into small data section (MIPS / Hexagon)">;
+def G_EQ : Joined<["-"], "G=">, Flags<[DriverOption]>, Group<m_Group>, Alias<G>;
+def H : Flag<["-"], "H">, Flags<[CC1Option]>, Group<Preprocessor_Group>,
     HelpText<"Show header includes and nesting depth">;
-def I_ : Flag<["-"], "I-">, Group<I_Group>;
-def I : JoinedOrSeparate<["-"], "I">, Group<I_Group>, Flags<[CC1Option,CC1AsOption]>,
+def I_ : Flag<["-"], "I-">, Group<I_Group>,
+    HelpText<"Restrict all prior -I flags to double-quoted inclusion and "
+             "remove current directory from include path">;
+def I : JoinedOrSeparate<["-"], "I">, Group<I_Group>,
+    Flags<[CC1Option,CC1AsOption]>, MetaVarName<"<dir>">,
     HelpText<"Add directory to include search path">;
-def L : JoinedOrSeparate<["-"], "L">, Flags<[RenderJoined]>, Group<Link_Group>;
+def L : JoinedOrSeparate<["-"], "L">, Flags<[RenderJoined]>, Group<Link_Group>,
+    MetaVarName<"<dir>">, HelpText<"Add directory to library search path">;
 def MD : Flag<["-"], "MD">, Group<M_Group>,
     HelpText<"Write a depfile containing user and system headers">;
 def MMD : Flag<["-"], "MMD">, Group<M_Group>,
@@ -337,9 +368,9 @@ def MT : JoinedOrSeparate<["-"], "MT">, Group<M_Group>, Flags<[CC1Option]>,
     HelpText<"Specify name of main file output in depfile">;
 def MV : Flag<["-"], "MV">, Group<M_Group>, Flags<[CC1Option]>,
     HelpText<"Use NMake/Jom format for the depfile">;
-def Mach : Flag<["-"], "Mach">;
-def O0 : Flag<["-"], "O0">, Group<O_Group>, Flags<[CC1Option]>;
-def O4 : Flag<["-"], "O4">, Group<O_Group>, Flags<[CC1Option]>;
+def Mach : Flag<["-"], "Mach">, Group<Link_Group>;
+def O0 : Flag<["-"], "O0">, Group<O_Group>, Flags<[CC1Option, HelpHidden]>;
+def O4 : Flag<["-"], "O4">, Group<O_Group>, Flags<[CC1Option, HelpHidden]>;
 def ObjCXX : Flag<["-"], "ObjC++">, Flags<[DriverOption]>,
   HelpText<"Treat source input files as Objective-C++ inputs">;
 def ObjC : Flag<["-"], "ObjC">, Flags<[DriverOption]>,
@@ -347,12 +378,12 @@ def ObjC : Flag<["-"], "ObjC">, Flags<[DriverOption]>,
 def O : Joined<["-"], "O">, Group<O_Group>, Flags<[CC1Option]>;
 def O_flag : Flag<["-"], "O">, Flags<[CC1Option]>, Alias<O>, AliasArgs<["2"]>;
 def Ofast : Joined<["-"], "Ofast">, Group<O_Group>, Flags<[CC1Option]>;
-def P : Flag<["-"], "P">, Flags<[CC1Option]>,
+def P : Flag<["-"], "P">, Flags<[CC1Option]>, Group<Preprocessor_Group>,
   HelpText<"Disable linemarker output in -E mode">;
-def Qn : Flag<["-"], "Qn">;
+def Qn : Flag<["-"], "Qn">, IgnoredGCCCompat;
 def Qunused_arguments : Flag<["-"], "Qunused-arguments">, Flags<[DriverOption, CoreOption]>,
   HelpText<"Don't emit warning for unused driver arguments">;
-def Q : Flag<["-"], "Q">;
+def Q : Flag<["-"], "Q">, IgnoredGCCCompat;
 def Rpass_EQ : Joined<["-"], "Rpass=">, Group<R_value_Group>, Flags<[CC1Option]>,
   HelpText<"Report transformations performed by optimization passes whose "
            "name matches the given POSIX regular expression">;
@@ -368,20 +399,25 @@ def R_Joined : Joined<["-"], "R">, Group<R_Group>, Flags<[CC1Option, CoreOption]
   MetaVarName<"<remark>">, HelpText<"Enable the specified remark">;
 def S : Flag<["-"], "S">, Flags<[DriverOption,CC1Option]>, Group<Action_Group>,
   HelpText<"Only run preprocess and compilation steps">;
-def Tbss : JoinedOrSeparate<["-"], "Tbss">, Group<T_Group>;
-def Tdata : JoinedOrSeparate<["-"], "Tdata">, Group<T_Group>;
-def Ttext : JoinedOrSeparate<["-"], "Ttext">, Group<T_Group>;
-def T : JoinedOrSeparate<["-"], "T">, Group<T_Group>;
-def U : JoinedOrSeparate<["-"], "U">, Group<CompileOnly_Group>, Flags<[CC1Option]>;
+def Tbss : JoinedOrSeparate<["-"], "Tbss">, Group<T_Group>,
+  MetaVarName<"<addr">, HelpText<"Set starting address of BSS to <addr>">;
+def Tdata : JoinedOrSeparate<["-"], "Tdata">, Group<T_Group>,
+  MetaVarName<"<addr">, HelpText<"Set starting address of BSS to <addr>">;
+def Ttext : JoinedOrSeparate<["-"], "Ttext">, Group<T_Group>,
+  MetaVarName<"<addr">, HelpText<"Set starting address of BSS to <addr>">;
+def T : JoinedOrSeparate<["-"], "T">, Group<T_Group>,
+  MetaVarName<"<script>">, HelpText<"Specify <script> as linker script">;
+def U : JoinedOrSeparate<["-"], "U">, Group<Preprocessor_Group>,
+  Flags<[CC1Option]>, MetaVarName<"<macro>">, HelpText<"Undefine macro <macro>">;
 def V : JoinedOrSeparate<["-"], "V">, Flags<[DriverOption, Unsupported]>;
 def Wa_COMMA : CommaJoined<["-"], "Wa,">,
   HelpText<"Pass the comma separated arguments in <arg> to the assembler">,
   MetaVarName<"<arg>">;
-def Wall : Flag<["-"], "Wall">, Group<W_Group>, Flags<[CC1Option]>;
-def WCL4 : Flag<["-"], "WCL4">, Group<W_Group>, Flags<[CC1Option]>;
-def Wdeprecated : Flag<["-"], "Wdeprecated">, Group<W_Group>, Flags<[CC1Option]>;
+def Wall : Flag<["-"], "Wall">, Group<W_Group>, Flags<[CC1Option, HelpHidden]>;
+def WCL4 : Flag<["-"], "WCL4">, Group<W_Group>, Flags<[CC1Option, HelpHidden]>;
+def Wdeprecated : Flag<["-"], "Wdeprecated">, Group<W_Group>, Flags<[CC1Option]>,
+  HelpText<"Enable warnings for deprecated constructs and define __DEPRECATED">;
 def Wno_deprecated : Flag<["-"], "Wno-deprecated">, Group<W_Group>, Flags<[CC1Option]>;
-def Wextra : Flag<["-"], "Wextra">, Group<W_Group>, Flags<[CC1Option]>;
 def Wl_COMMA : CommaJoined<["-"], "Wl,">, Flags<[LinkerInput, RenderAsInput]>,
   HelpText<"Pass the comma separated arguments in <arg> to the linker">,
   MetaVarName<"<arg>">, Group<Link_Group>;
@@ -392,16 +428,18 @@ def Wnonportable_cfstrings : Joined<["-"], "Wnonportable-cfstrings">, Group<W_Gr
   Flags<[CC1Option]>;
 def Wp_COMMA : CommaJoined<["-"], "Wp,">,
   HelpText<"Pass the comma separated arguments in <arg> to the preprocessor">,
-  MetaVarName<"<arg>">;
-def Wwrite_strings : Flag<["-"], "Wwrite-strings">, Group<W_Group>, Flags<[CC1Option]>;
-def Wno_write_strings : Flag<["-"], "Wno-write-strings">, Group<W_Group>, Flags<[CC1Option]>;
+  MetaVarName<"<arg>">, Group<Preprocessor_Group>;
+def Wwrite_strings : Flag<["-"], "Wwrite-strings">, Group<W_Group>, Flags<[CC1Option, HelpHidden]>;
+def Wno_write_strings : Flag<["-"], "Wno-write-strings">, Group<W_Group>, Flags<[CC1Option, HelpHidden]>;
 def W_Joined : Joined<["-"], "W">, Group<W_Group>, Flags<[CC1Option, CoreOption]>,
   MetaVarName<"<warning>">, HelpText<"Enable the specified warning">;
 def Xanalyzer : Separate<["-"], "Xanalyzer">,
-  HelpText<"Pass <arg> to the static analyzer">, MetaVarName<"<arg>">;
+  HelpText<"Pass <arg> to the static analyzer">, MetaVarName<"<arg>">,
+  Group<StaticAnalyzer_Group>;
 def Xarch__ : JoinedAndSeparate<["-"], "Xarch_">, Flags<[DriverOption]>;
 def Xassembler : Separate<["-"], "Xassembler">,
-  HelpText<"Pass <arg> to the assembler">, MetaVarName<"<arg>">;
+  HelpText<"Pass <arg> to the assembler">, MetaVarName<"<arg>">,
+  Group<CompileOnly_Group>;
 def Xclang : Separate<["-"], "Xclang">,
   HelpText<"Pass <arg> to the clang compiler">, MetaVarName<"<arg>">,
   Flags<[DriverOption, CoreOption]>, Group<CompileOnly_Group>;
@@ -415,11 +453,12 @@ def z : Separate<["-"], "z">, Flags<[LinkerInput, RenderAsInput]>,
 def Xlinker : Separate<["-"], "Xlinker">, Flags<[LinkerInput, RenderAsInput]>,
   HelpText<"Pass <arg> to the linker">, MetaVarName<"<arg>">,
   Group<Link_Group>;
-def Xpreprocessor : Separate<["-"], "Xpreprocessor">,
+def Xpreprocessor : Separate<["-"], "Xpreprocessor">, Group<Preprocessor_Group>,
   HelpText<"Pass <arg> to the preprocessor">, MetaVarName<"<arg>">;
-def X_Flag : Flag<["-"], "X">;
-def X_Joined : Joined<["-"], "X">;
+def X_Flag : Flag<["-"], "X">, Group<Link_Group>;
+def X_Joined : Joined<["-"], "X">, IgnoredGCCCompat;
 def Z_Flag : Flag<["-"], "Z">, Group<Link_Group>;
+// FIXME: All we do with this is reject it. Remove.
 def Z_Joined : Joined<["-"], "Z">;
 def all__load : Flag<["-"], "all_load">;
 def allowable__client : Separate<["-"], "allowable_client">;
@@ -465,7 +504,7 @@ def current__version : JoinedOrSeparate<["-"], "current_version">;
 def cxx_isystem : JoinedOrSeparate<["-"], "cxx-isystem">, Group<clang_i_Group>,
   HelpText<"Add directory to the C++ SYSTEM include search path">, Flags<[CC1Option]>,
   MetaVarName<"<directory>">;
-def c : Flag<["-"], "c">, Flags<[DriverOption]>,
+def c : Flag<["-"], "c">, Flags<[DriverOption]>, Group<Action_Group>,
   HelpText<"Only run preprocess, compile, and assemble steps">;
 def cuda_device_only : Flag<["--"], "cuda-device-only">,
   HelpText<"Compile CUDA code for device only">;
@@ -1806,7 +1845,8 @@ def mno_incremental_linker_compatible : Flag<["-"], "mno-incremental-linker-comp
   HelpText<"(integrated-as) Emit an object file which cannot be used with an incremental linker">;
 def mrtd : Flag<["-"], "mrtd">, Group<m_Group>, Flags<[CC1Option]>,
   HelpText<"Make StdCall calling convention the default">;
-def msmall_data_threshold_EQ : Joined <["-"], "msmall-data-threshold=">, Group<m_Group>;
+def msmall_data_threshold_EQ : Joined <["-"], "msmall-data-threshold=">,
+  Group<m_Group>, Alias<G>;
 def msoft_float : Flag<["-"], "msoft-float">, Group<m_Group>, Flags<[CC1Option]>,
   HelpText<"Use software floating point">;
 def mno_implicit_float : Flag<["-"], "mno-implicit-float">, Group<m_Group>,
@@ -2394,13 +2434,6 @@ defm devirtualize : BooleanFFlag<"devirtualize">, Group<clang_ignored_gcc_optimi
 defm devirtualize_speculatively : BooleanFFlag<"devirtualize-speculatively">,
     Group<clang_ignored_gcc_optimization_f_Group>;
 
-// gfortran options that we recognize in the driver and pass along when
-// invoking GCC to compile Fortran code.
-def gfortran_Group : OptionGroup<"<gfortran group>">,
-                     DocName<"Fortran compilation flags">, DocBrief<[{
-Flags that will be passed onto the ``gfortran`` compiler when Clang is given
-a Fortran input.}]>;
-
 // Generic gfortran options.
 def A_DASH : Joined<["-"], "A-">, Group<gfortran_Group>;
 def J : JoinedOrSeparate<["-"], "J">, Flags<[RenderJoined]>, Group<gfortran_Group>;
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index a4e797587c..eb51aaf394 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -3185,8 +3185,7 @@ std::string HexagonToolChain::getHexagonTargetDir(
 Optional<unsigned> HexagonToolChain::getSmallDataThreshold(
       const ArgList &Args) {
   StringRef Gn = "";
-  if (Arg *A = Args.getLastArg(options::OPT_G, options::OPT_G_EQ,
-                               options::OPT_msmall_data_threshold_EQ)) {
+  if (Arg *A = Args.getLastArg(options::OPT_G)) {
     Gn = A->getValue();
   } else if (Args.getLastArg(options::OPT_shared, options::OPT_fpic,
                              options::OPT_fPIC)) {