lld-link: Add --color-diagnostics(={always,never,auto})?, --no-color-diagnostics flags.

[thakis]

Summary

This is most useful when using lld-link on a non-Win host (but it might become useful on Windows too if lld also grows a fansi-escape-codes flag).

Also make the help for --color-diagnostic mention the valid values in ELF and wasm, and print the flag name with two dashes in diags, since the one-dash form is seen as a list of many one-letter flags in some contexts.

[thakis]

(This flag is now duplicated in COFF, ELF, and wasm. I didn't see any .td file in Common, so it wasn't obvious to me how to share it though.)

[ruiu]

Is there any reason to make it exactly the same option name as Unix linkers? I mean, all the other options in the COFF linker are Windows-ish, e.g. /something. So I wonder if /colordiagnostics{,:always,:never,:auto} is better.

lld/COFF/DriverUtils.cpp

766

nit: no else after return.

770

nit: consistently add {} if you add {} to some else or else if.

[thakis]

In D46693#1094466, @ruiu wrote:

Is there any reason to make it exactly the same option name as Unix linkers? I mean, all the other options in the COFF linker are Windows-ish, e.g. /something. So I wonder if /colordiagnostics{,:always,:never,:auto} is better.

For flags that link.exe doesn't have and that are shared with ld.lld, I thought we usually use the -- prefix to reduce the risk of collision with future link.exe flags, and for consistency (cf --version, --rsp-quoting).

(Will fix the nits, also in the ELF and wasm versions.)

[ruiu]

LGTM

That makes sense, though we already have /linkrepro instead of --reproduce because we wanted to make it more MS linker-ish than the Unix linker. In hindsight, we probably should have named it --reproduce even on Windows though.

[thakis]

r332012, thanks!

lld/COFF/DriverUtils.cpp

#define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12)      \
   {X1, X2, X10,         X11,         OPT_##ID, llvm::opt::Option::KIND##Class, \
    X9, X8, OPT_##GROUP, OPT_##ALIAS, X7,       X12},
 #include "Options.inc"
 #undef OPTION
 };
 
 COFFOptTable::COFFOptTable() : OptTable(InfoTable, true) {}
 
+// Set color diagnostics according to --color-diagnostics={auto,always,never}
+// or --no-color-diagnostics flags.
+static void handleColorDiagnostics(opt::InputArgList &Args) {
+  auto *Arg = Args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
+                              OPT_no_color_diagnostics);
+  if (!Arg)
+    return;
+  else if (Arg->getOption().getID() == OPT_color_diagnostics)
+    errorHandler().ColorDiagnostics = true;
+  else if (Arg->getOption().getID() == OPT_no_color_diagnostics)
+    errorHandler().ColorDiagnostics = false;
+  else {
+    StringRef S = Arg->getValue();
+    if (S == "always")
+      errorHandler().ColorDiagnostics = true;
+    else if (S == "never")
+      errorHandler().ColorDiagnostics = false;
+    else if (S != "auto")
+      error("unknown option: --color-diagnostics=" + S);
+  }
+}
+
 static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &Args) {
   if (auto *Arg = Args.getLastArg(OPT_rsp_quoting)) {
     StringRef S = Arg->getValue();
     if (S != "windows" && S != "posix")
       error("invalid response file quoting: " + S);
     if (S == "windows")
       return cl::TokenizeWindowsCommandLine;
     return cl::TokenizeGNUCommandLine;
if (Args.hasArg(OPT_verbose) && Argv.size() != Vec.size()) {
     message(Msg);
   }
 
   // Handle /WX early since it converts missing argument warnings to errors.
   errorHandler().FatalWarnings = Args.hasFlag(OPT_WX, OPT_WX_no, false);
 
   if (MissingCount)
     fatal(Twine(Args.getArgString(MissingIndex)) + ": missing argument");
+
+  handleColorDiagnostics(Args);
+
   for (auto *Arg : Args.filtered(OPT_UNKNOWN))
     warn("ignoring unknown argument: " + Arg->getSpelling());
   return Args;
 }
 
 // Tokenizes and parses a given string as command line in .drective section.
 // /EXPORT options are processed in fastpath.
 std::pair<opt::InputArgList, std::vector<StringRef>>

lld/COFF/Options.td

multiclass B<string name, string help_on, string help_off> {
   def "" : F<name>, HelpText<help_on>;
   def _no : F<name#":no">, HelpText<help_off>;
 }
 
 def align   : P<"align", "Section alignment">;
 def aligncomm : P<"aligncomm", "Set common symbol alignment">;
 def alternatename : P<"alternatename", "Define weak alias">;
 def base    : P<"base", "Base address of the program">;
+def color_diagnostics: Flag<["--"], "color-diagnostics">,
+  HelpText<"Use colors in diagnostics">;
+def color_diagnostics_eq: Joined<["--"], "color-diagnostics=">,
+  HelpText<"Use colors in diagnostics; one of 'always', 'never', 'auto'">;
 def defaultlib : P<"defaultlib", "Add the library to the list of input files">;
 def delayload : P<"delayload", "Delay loaded DLL name">;
 def entry   : P<"entry", "Name of entry point symbol">;
 def errorlimit : P<"errorlimit",
     "Maximum number of errors to emit before stopping (0 = no limit)">;
 def export  : P<"export", "Export a function">;
 // No help text because /failifmismatch is not intended to be used by the user.
 def failifmismatch : P<"failifmismatch", "">;

 def machine : P<"machine", "Specify target platform">;
 def merge   : P<"merge", "Combine sections">;
 def mllvm   : P<"mllvm", "Options to pass to LLVM">;
 def nodefaultlib : P<"nodefaultlib", "Remove a default library">;
 def opt     : P<"opt", "Control optimizations">;
 def order   : P<"order", "Put functions in order">;
 def out     : P<"out", "Path to file to write output">;
 def natvis : P<"natvis", "Path to natvis file to embed in the PDB">;
+def no_color_diagnostics: F<"no-color-diagnostics">,
+  HelpText<"Do not use colors in diagnostics">;
 def pdb : P<"pdb", "PDB file path">;
 def pdbaltpath : P<"pdbaltpath", "PDB file path to embed in the image">;
 def section : P<"section", "Specify section attributes">;
 def stack   : P<"stack", "Size of the stack">;
 def stub    : P<"stub", "Specify DOS stub file">;
 def subsystem : P<"subsystem", "Specify subsystem">;
 def version : P<"version", "Specify a version number in the PE header">;
 def wholearchive_file : P<"wholearchive", "Include all object files from this archive">;

lld/ELF/DriverUtils.cpp

else if (Arg->getOption().getID() == OPT_no_color_diagnostics)
     errorHandler().ColorDiagnostics = false;
   else {
     StringRef S = Arg->getValue();
     if (S == "always")
       errorHandler().ColorDiagnostics = true;
     else if (S == "never")
       errorHandler().ColorDiagnostics = false;
     else if (S != "auto")
-      error("unknown option: -color-diagnostics=" + S);
+      error("unknown option: --color-diagnostics=" + S);
   }
 }
 
 static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &Args) {
   if (auto *Arg = Args.getLastArg(OPT_rsp_quoting)) {
     StringRef S = Arg->getValue();
     if (S != "windows" && S != "posix")
       error("invalid response file quoting: " + S);

lld/ELF/Options.td

 
 // -chroot doesn't have a help text because it is an internal option.
 defm chroot: Eq<"chroot">;
 
 def color_diagnostics: F<"color-diagnostics">,
   HelpText<"Use colors in diagnostics">;
 
 def color_diagnostics_eq: J<"color-diagnostics=">,
-  HelpText<"Use colors in diagnostics">;
+  HelpText<"Use colors in diagnostics; one of 'always', 'never', 'auto'">;
 
 defm cref: B<"cref",
     "Output cross reference table",
     "Do not output cross reference table">;
 
 defm define_common: B<"define-common",
     "Assign space to common symbols",
     "Do not assign space to common symbols">;

lld/test/COFF/color-diagnostics.test

+# Windows command prompt doesn't support ANSI escape sequences.
+# REQUIRES: shell
+
+# RUN: not lld-link -xyz --color-diagnostics /nosuchfile 2>&1 \
+# RUN:   | FileCheck -check-prefix=COLOR %s
+# RUN: not lld-link -xyz --color-diagnostics=always /nosuchfile 2>&1 \
+# RUN:   | FileCheck -check-prefix=COLOR %s
+
+# COLOR: {{lld-link: .\[0;1;35mwarning: .\[0mignoring unknown argument: -xyz}}
+# COLOR: {{lld-link: .\[0;1;31merror: .\[0mcould not open /nosuchfile}}
+
+# RUN: not lld-link /nosuchfile 2>&1 | FileCheck -check-prefix=NOCOLOR %s
+# RUN: not lld-link -color-diagnostics=never /nosuchfile 2>&1 \
+# RUN:   | FileCheck -check-prefix=NOCOLOR %s
+# RUN: not lld-link -color-diagnostics=always -no-color-diagnostics \
+# RUN:   /nosuchfile 2>&1 | FileCheck -check-prefix=NOCOLOR %s
+
+# NOCOLOR: lld-link: error: could not open /nosuchfile

lld/wasm/Driver.cpp

else if (Arg->getOption().getID() == OPT_no_color_diagnostics)
     errorHandler().ColorDiagnostics = false;
   else {
     StringRef S = Arg->getValue();
     if (S == "always")
       errorHandler().ColorDiagnostics = true;
     if (S == "never")
       errorHandler().ColorDiagnostics = false;
     if (S != "auto")
-      error("unknown option: -color-diagnostics=" + S);
+      error("unknown option: --color-diagnostics=" + S);
   }
 }
 
 // Find a file by concatenating given paths.
 static Optional<std::string> findFile(StringRef Path1, const Twine &Path2) {
   SmallString<128> S;
   path::append(S, Path1, Path2);
   if (fs::exists(S))

lld/wasm/Options.td

multiclass B<string name, string help1, string help2> {
   def no_ # NAME: Flag<["--", "-"], "no-" # name>, HelpText<help2>;
 }
 
 // The follow flags are shared with the ELF linker
 def color_diagnostics: F<"color-diagnostics">,
   HelpText<"Use colors in diagnostics">;
 
 def color_diagnostics_eq: J<"color-diagnostics=">,
-  HelpText<"Use colors in diagnostics">;
+  HelpText<"Use colors in diagnostics; one of 'always', 'never', 'auto'">;
 
 defm demangle: B<"demangle",
     "Demangle symbol names",
     "Do not demangle symbol names">;
 
 def entry: S<"entry">, MetaVarName<"<entry>">,
   HelpText<"Name of entry point symbol">;