[LLD][MinGW] Handle allow-multiple-definition flag

[mati865]

Summary

Basically copied from ELF driver.

[mstorsjo]

LGTM

lld/MinGW/Driver.cpp

 
 using namespace lld;
 using namespace llvm;
 
 // Create OptTable
 enum {
   OPT_INVALID = 0,
 #define OPTION(_1, _2, ID, _4, _5, _6, _7, _8, _9, _10, _11, _12) OPT_##ID,
 #include "Options.inc"
 #undef OPTION
 };
 
 // Create prefix string literals used in Options.td
 #define PREFIX(NAME, VALUE) static const char *const NAME[] = VALUE;
 #include "Options.inc"
 #undef PREFIX
 
bool mingw::link(ArrayRef<const char *> argsArr, bool canExitEarly,
   else
     add("-auto-import:no");
   if (args.hasFlag(OPT_enable_runtime_pseudo_reloc,
                    OPT_disable_runtime_pseudo_reloc, true))
     add("-runtime-pseudo-reloc");
   else
     add("-runtime-pseudo-reloc:no");
 
+  if (args.hasFlag(OPT_allow_multiple_definition,
+                   OPT_no_allow_multiple_definition, false))
+    add("-force:multiple");
+
   if (auto *a = args.getLastArg(OPT_icf)) {
     StringRef s = a->getValue();
     if (s == "all")
       add("-opt:icf");
     else if (s == "safe" || s == "none")
       add("-opt:noicf");
     else
       error("unknown parameter: --icf=" + s);

lld/MinGW/Options.td

 
 multiclass B<string name, string help1, string help2> {
   def NAME: Flag<["--", "-"], name>, HelpText<help1>;
   def no_ # NAME: Flag<["--", "-"], "no-" # name>, HelpText<help2>;
 }
 
 def L: JoinedOrSeparate<["-"], "L">, MetaVarName<"<dir>">,
   HelpText<"Add a directory to the library search path">;
+defm allow_multiple_definition: B<"allow-multiple-definition",
+    "Allow multiple definitions",
+    "Do not allow multiple definitions (default)">;
 def Bdynamic: F<"Bdynamic">, HelpText<"Link against shared libraries">;
 def Bstatic: F<"Bstatic">, HelpText<"Do not link against shared libraries">;
 def disable_auto_import: F<"disable-auto-import">,
     HelpText<"Don't automatically import data symbols from other DLLs without dllimport">;
 def disable_runtime_pseudo_reloc: F<"disable-runtime-pseudo-reloc">,
     HelpText<"Don't do automatic imports that require runtime fixups">;
 def dynamicbase: F<"dynamicbase">, HelpText<"Enable ASLR">;
 def enable_auto_import: F<"enable-auto-import">,

lld/test/MinGW/driver.test

 RUN: ld.lld -### -m i386pep foo.o -section-alignment 0x2000 | FileCheck -check-prefix ALIGN %s
 RUN: ld.lld -### -m i386pep foo.o --section-alignment=0x2000 | FileCheck -check-prefix ALIGN %s
 RUN: ld.lld -### -m i386pep foo.o -section-alignment=0x2000 | FileCheck -check-prefix ALIGN %s
 ALIGN: -align:0x2000
 
 RUN: ld.lld -### -m i386pe foo.o -no-seh | FileCheck -check-prefix NOSEH %s
 RUN: ld.lld -### -m i386pe foo.o --no-seh | FileCheck -check-prefix NOSEH %s
 NOSEH: -noseh
+
+RUN: ld.lld -### -m i386pep foo.o --no-allow-multiple-definition --allow-multiple-definition | FileCheck -check-prefix ALLOW_MULTIPLE_DEFINITION %s
+RUN: ld.lld -### -m i386pep foo.o -no-allow-multiple-definition -allow-multiple-definition | FileCheck -check-prefix ALLOW_MULTIPLE_DEFINITION %s
+ALLOW_MULTIPLE_DEFINITION: -force:multiple
+
+RUN: ld.lld -### -m i386pep foo.o --allow-multiple-definition --no-allow-multiple-definition | FileCheck -check-prefix NO_ALLOW_MULTIPLE_DEFINITION %s
+RUN: ld.lld -### -m i386pep foo.o -allow-multiple-definition -no-allow-multiple-definition | FileCheck -check-prefix NO_ALLOW_MULTIPLE_DEFINITION %s
+NO_ALLOW_MULTIPLE_DEFINITION-NOT: -force:multiple