[LLD/MinGW]: Expose --thinlto-cache-dir

[thieta]

Summary

This came up in this comment here: https://reviews.llvm.org/D80425#inline-737983

and this seems like the more proper fix for sure.

[mstorsjo]

Looks great in general, a couple nitpicks

lld/MinGW/Driver.cpp

352

This option is the kind where you only have one (that's how the option is handled in COFF/Driver.cpp), so it's probably better to go with getLastArg() instead - you could place it next to e.g. OPT_reproduce.

lld/MinGW/Options.td

86

Not sure if this really needs a section of its own - I'd put it below in LLD specific options.

lld/test/MinGW/driver.test

247

Missing trailing newline

[MaskRay]

lld/MinGW/Options.td

86

This can be EqLong. In ELF, I did not know EqLong and added EEq.

[mstorsjo]

LGTM, thanks!

lld/MinGW/Options.td

98

Another nitpick: I try to keep these sorted alphabetically, so you could move it up above Xlink before committing.

[thieta]

Could you commit this for me Martin? I don't have access yet.

[mstorsjo]

In D80438#2052343, @thieta wrote:

Could you commit this for me Martin? I don't have access yet.

Sure, can do. What's your preferred form of git author line for this?

[thieta]

"Tobias Hieta <[e-mail]>" thanks!

lld/MinGW/Driver.cpp

else
     add("-alternatename:__image_base__=__ImageBase");
 
   for (auto *a : args.filtered(OPT_require_defined))
     add("-include:" + StringRef(a->getValue()));
   for (auto *a : args.filtered(OPT_undefined))
     add("-includeoptional:" + StringRef(a->getValue()));
   for (auto *a : args.filtered(OPT_delayload))
     add("-delayload:" + StringRef(a->getValue()));
+  for (auto *a : args.filtered(OPT_thinlto_cache_dir))
+    add("-lldltocache:" + StringRef(a->getValue()));
 
   std::vector<StringRef> searchPaths;
   for (auto *a : args.filtered(OPT_L)) {
     searchPaths.push_back(a->getValue());
     add("-libpath:" + StringRef(a->getValue()));
   }
 
   StringRef prefix = "";

lld/MinGW/Options.td

 def whole_archive: F<"whole-archive">,
     HelpText<"Include all object files for following archives">;
 def v: Flag<["-"], "v">, HelpText<"Display the version number">;
 def verbose: F<"verbose">, HelpText<"Verbose mode">;
 def version: F<"version">, HelpText<"Display the version number and exit">;
 defm require_defined: Eq<"require-defined",
      "Force symbol to be added to symbol table as an undefined one">;
 
+// ThinLTO options
+defm thinlto_cache_dir: Eq<"thinlto-cache-dir",
+  "Path to ThinLTO cached object file directory">;
+
 // LLD specific options
 def _HASH_HASH_HASH : Flag<["-"], "###">,
     HelpText<"Print (but do not run) the commands to run for this compilation">;
 def appcontainer: F<"appcontainer">, HelpText<"Set the appcontainer flag in the executable">;
 defm delayload: Eq<"delayload", "DLL to load only on demand">;
 def mllvm: S<"mllvm">;
 defm pdb: Eq<"pdb", "Output PDB debug info file, chosen implicitly if the argument is empty">;
 def Xlink : J<"Xlink=">, MetaVarName<"<arg>">,
     HelpText<"Pass <arg> to the COFF linker">;
 
 // Alias
 def alias_entry_e: JoinedOrSeparate<["-"], "e">, Alias<entry>;
 def alias_strip_s: Flag<["-"], "s">, Alias<strip_all>;
 def alias_strip_S: Flag<["-"], "S">, Alias<strip_debug>;
 def alias_undefined_u: JoinedOrSeparate<["-"], "u">, Alias<undefined>;
 
 // Ignored options
 def: Joined<["-"], "O">;
 def: F<"build-id">;

lld/test/MinGW/driver.test

 RUN: ld.lld -### -m i386pep foo.o | FileCheck -check-prefix ENABLE_RUNTIME_PSEUDO_RELOC %s
 RUN: ld.lld -### -m i386pep foo.o --disable-runtime-pseudo-reloc --enable-runtime-pseudo-reloc | FileCheck -check-prefix ENABLE_RUNTIME_PSEUDO_RELOC %s
 RUN: ld.lld -### -m i386pep foo.o -enable-runtime-pseudo-reloc | FileCheck -check-prefix ENABLE_RUNTIME_PSEUDO_RELOC %s
 ENABLE_RUNTIME_PSEUDO_RELOC: -runtime-pseudo-reloc{{ }}
 
 RUN: ld.lld -### -m i386pep foo.o --disable-runtime-pseudo-reloc | FileCheck -check-prefix DISABLE_RUNTIME_PSEUDO_RELOC %s
 RUN: ld.lld -### -m i386pep foo.o -disable-runtime-pseudo-reloc | FileCheck -check-prefix DISABLE_RUNTIME_PSEUDO_RELOC %s
 DISABLE_RUNTIME_PSEUDO_RELOC: -runtime-pseudo-reloc:no
+
+RUN: ld.lld -### foo.o -m i386pe --thinlto-cache-dir=_foo | FileCheck -check-prefix=THINLTO_CACHEDIR %s
+THINLTO_CACHEDIR: -lldltocache:_foo
 No newline at end of file