Add typo correction for command-line flags to ELF and COFF lld drivers

[thakis]

Summary

For lld-link, unknown '/'-style flags are treated as filenames on POSIX
systems, so only '-'-style flags get typo correction for now. This
matches clang-cl.

PR37006.

[ruiu]

LGTM

Looks great!

COFF/DriverUtils.cpp

opt::InputArgList ArgParser::parse(ArrayRef<const char *> Argv) {
   // 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());
+  for (auto *Arg : Args.filtered(OPT_UNKNOWN)) {
+    std::string Nearest;
+    if (Table.findNearest(Arg->getAsString(Args), Nearest) > 1)
+      warn("ignoring unknown argument '" + Arg->getSpelling() + "'");
+    else
+      warn("ignoring unknown argument '" + Arg->getSpelling() +
+           "', did you mean '" + Nearest + "'");
+  }
 
   if (Args.hasArg(OPT_lib))
     warn("ignoring /lib since it's not the first argument");
 
   return Args;
 }
 
 // Tokenizes and parses a given string as command line in .drective section.

ELF/DriverUtils.cpp

opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
   cl::ExpandResponseFiles(Saver, getQuotingStyle(Args), Vec);
   concatLTOPluginOptions(Vec);
   Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
 
   handleColorDiagnostics(Args);
   if (MissingCount)
     error(Twine(Args.getArgString(MissingIndex)) + ": missing argument");
 
-  for (auto *Arg : Args.filtered(OPT_UNKNOWN))
-    error("unknown argument: " + Arg->getSpelling());
+  for (auto *Arg : Args.filtered(OPT_UNKNOWN)) {
+    std::string Nearest;
+    if (findNearest(Arg->getAsString(Args), Nearest) > 1)
+      error("unknown argument '" + Arg->getSpelling() + "'");
+    else
+      error("unknown argument '" + Arg->getSpelling() + "', did you mean '" +
+            Nearest + "'");
+  }
   return Args;
 }
 
 void elf::printHelp() {
   ELFOptTable().PrintHelp(
       outs(), (Config->ProgName + " [options] file...").str().c_str(), "lld",
       false /*ShowHidden*/, true /*ShowAllAliases*/);
   outs() << "\n";

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;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

test/COFF/driver.test

 LIBHELP: OVERVIEW: LLVM Lib
 
 # RUN: not lld-link /WX /lib 2>&1 | FileCheck -check-prefix=LIBBAD %s
 LIBBAD: ignoring /lib since it's not the first argument
 
 # RUN: yaml2obj < %p/Inputs/hello32.yaml > %t.obj
 # RUN: not lld-link /out:/ %t.obj 2>&1 | FileCheck -check-prefix=DIR %s
 DIR: cannot open output file
+
+# RUN: not lld-link -version 2>&1 | FileCheck -check-prefix=SPELLVERSION %s
+SPELLVERSION: ignoring unknown argument '-version', did you mean '--version'
+SPELLVERSION: no input files
+
+# RUN: not lld-link -nodefaultlibs 2>&1 | FileCheck -check-prefix=SPELLNODEFAULTLIB %s
+SPELLNODEFAULTLIB: ignoring unknown argument '-nodefaultlibs', did you mean '-nodefaultlib'
+SPELLNODEFAULTLIB: no input files

test/COFF/wx.s

 # REQUIRES: x86
 
 # RUN: llvm-mc -triple=x86_64-windows-msvc -filetype=obj -o %t.obj %s
 # RUN: not lld-link /out:%t.exe /entry:main -notarealoption /WX %t.obj 2>&1 | \
 # RUN:   FileCheck -check-prefix=ERROR %s
 # RUN: not lld-link /out:%t.exe /entry:main -notarealoption /WX:NO /WX %t.obj 2>&1 | \
 # RUN:   FileCheck -check-prefix=ERROR %s
 # RUN: lld-link /out:%t.exe /entry:main -notarealoption /WX /WX:NO %t.obj 2>&1 | \
 # RUN:   FileCheck -check-prefix=WARNING %s
 
-# ERROR: error: ignoring unknown argument: -notarealoption
-# WARNING: warning: ignoring unknown argument: -notarealoption
+# ERROR: error: ignoring unknown argument '-notarealoption'
+# WARNING: warning: ignoring unknown argument '-notarealoption'
 
 .text
 .global main
 main:
   ret

test/ELF/basic.s

 # RUN: not ld.lld %t.no.such.file -o %t2 2>&1 | \
 # RUN:  FileCheck --check-prefix=CANNOT_OPEN %s
 # CANNOT_OPEN: cannot open {{.*}}.no.such.file: {{[Nn]}}o such file or directory
 
 # RUN: not ld.lld %t -o 2>&1 | FileCheck --check-prefix=NO_O_VAL %s
 # NO_O_VAL: -o: missing argument
 
 # RUN: not ld.lld --foo 2>&1 | FileCheck --check-prefix=UNKNOWN %s
-# UNKNOWN: unknown argument: --foo
+# UNKNOWN: unknown argument '--foo'
 
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
 # RUN: not ld.lld %t %t -o %t2 2>&1 | FileCheck --check-prefix=DUP %s
 # DUP:      duplicate symbol: _start
 # DUP-NEXT: >>> defined at {{.*}}:(.text+0x0)
 # DUP-NEXT: >>> defined at {{.*}}:(.text+0x0)
 
 # RUN: not ld.lld %t -o %t -m wrong_emul_fbsd 2>&1 | FileCheck --check-prefix=UNKNOWN_EMUL %s

test/ELF/color-diagnostics.test

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

test/ELF/driver.test

 # REQUIRES: x86
 
 # RUN: not ld.lld --unknown1 --unknown2 -m foo /no/such/file -lnosuchlib \
 # RUN:   2>&1 | FileCheck -check-prefix=UNKNOWN %s
 
-# UNKNOWN: unknown argument: --unknown1
-# UNKNOWN: unknown argument: --unknown2
+# UNKNOWN: unknown argument '--unknown1'
+# UNKNOWN: unknown argument '--unknown2'
 # UNKNOWN: unknown emulation: foo
 # UNKNOWN: cannot open /no/such/file
 # UNKNOWN: unable to find library -lnosuchlib
 
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
 # RUN: not ld.lld %t -o /no/such/file 2>&1 | FileCheck -check-prefix=MISSING %s
 # MISSING: cannot open output file /no/such/file
 
 # RUN: ld.lld --help 2>&1 | FileCheck -check-prefix=HELP %s
 # HELP: USAGE:
 # HELP: : supported targets:{{.*}} elf
 
 # RUN: ld.lld --version 2>&1 | FileCheck -check-prefix=VERSION %s
 # RUN: ld.lld -v 2>&1 | FileCheck -check-prefix=VERSION %s
 # RUN: not ld.lld -v xyz 2>&1 | FileCheck -check-prefix=VERSION %s
 # VERSION: LLD {{.*}} (compatible with GNU linkers)
 
+# RUN: not ld.lld --versin 2>&1 | FileCheck -check-prefix=SPELLVERSION %s
+# SPELLVERSION: unknown argument '--versin', did you mean '--version'
+
 ## Attempt to link DSO with -r
 # RUN: ld.lld -shared %t -o %t.so
 # RUN: not ld.lld -r %t.so %t -o %tfail 2>&1 | FileCheck -check-prefix=ERR %s
 # ERR: attempted static link of dynamic object
 
 ## Attempt to use -r and -shared together
 # RUN: not ld.lld -r -shared %t -o %tfail 2>&1 | FileCheck -check-prefix=ERR2 %s
 # ERR2: -r and -shared may not be used together