[LLD] [MinGW] Implement --disable-reloc-section, mapped to /fixed

[mstorsjo]

Summary

Since binutils 2.36, GNU ld defaults to emitting base relocations,
and that version added the new option --disable-reloc-section to
disable it.

[rnk]

lgtm

[mati865]

lgtm

lld/MinGW/Driver.cpp

if (args.getLastArgValue(OPT_m) != "thumb2pe" &&
     add("-dynamicbase:no");
   if (args.hasFlag(OPT_disable_high_entropy_va, OPT_high_entropy_va, false))
     add("-highentropyva:no");
   if (args.hasFlag(OPT_disable_nxcompat, OPT_nxcompat, false))
     add("-nxcompat:no");
   if (args.hasFlag(OPT_disable_tsaware, OPT_tsaware, false))
     add("-tsaware:no");
 
+  if (args.hasFlag(OPT_disable_reloc_section, OPT_enable_reloc_section, false))
+    add("-fixed");
+
   if (args.hasFlag(OPT_no_insert_timestamp, OPT_insert_timestamp, false))
     add("-timestamp:0");
 
   if (args.hasFlag(OPT_gc_sections, OPT_no_gc_sections, false))
     add("-opt:ref");
   else
     add("-opt:noref");
 

lld/MinGW/Options.td

multiclass B<string name, string help1, string help2> {
   def no_ # NAME: Flag<["--", "-"], "no-" # name>, HelpText<help2>;
 }
 
 multiclass B_disable<string name, string help1, string help2> {
   def NAME: Flag<["--", "-"], name>, HelpText<help1>;
   def disable_ # NAME: Flag<["--", "-"], "disable-" # name>, HelpText<help2>;
 }
 
+multiclass B_enable_disable<string name, string help1, string help2> {
+  def enable_ # NAME: Flag<["--", "-"], "enable-" # name>, HelpText<help1>;
+  def disable_ # NAME: Flag<["--", "-"], "disable-" # 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">;
 defm demangle: B<"demangle",

 defm nxcompat: B_disable<"nxcompat",
     "Set the 'nxcompat' flag in the executable", "Don't set the 'nxcompat' flag">;
 def large_address_aware: Flag<["--"], "large-address-aware">,
     HelpText<"Enable large addresses">;
 def o: JoinedOrSeparate<["-"], "o">, MetaVarName<"<path>">,
   HelpText<"Path to file to write output">;
 defm out_implib: Eq<"out-implib", "Import library name">;
 defm output_def: Eq<"output-def", "Output def file">;
+defm reloc_section: B_enable_disable<"reloc-section",
+     "Enable base relocations", "Disable base relocations">;
 defm section_alignment: Eq<"section-alignment", "Set section alignment">;
 def shared: F<"shared">, HelpText<"Build a shared object">;
 defm subs: Eq<"subsystem", "Specify subsystem">;
 defm stack: Eq<"stack", "Set size of the initial stack">;
 def strip_all: F<"strip-all">,
     HelpText<"Omit all symbol information from the output binary">;
 def strip_debug: F<"strip-debug">,
     HelpText<"Omit all debug information, but keep symbol information">;

lld/test/MinGW/driver.test

 
 RUN: ld.lld -### -m i386pe foo.o -tsaware -disable-tsaware 2>&1 | FileCheck -check-prefix DISABLE-TSAWARE %s
 RUN: ld.lld -### -m i386pe foo.o --tsaware --disable-tsaware 2>&1 | FileCheck -check-prefix DISABLE-TSAWARE %s
 DISABLE-TSAWARE: -tsaware:no
 RUN: ld.lld -### -m i386pe foo.o -disable-tsaware -tsaware 2>&1 | FileCheck -check-prefix NO-DISABLE-TSAWARE %s
 RUN: ld.lld -### -m i386pe foo.o --disable-tsaware --tsaware 2>&1 | FileCheck -check-prefix NO-DISABLE-TSAWARE %s
 NO-DISABLE-TSAWARE-NOT: -tsaware:no
 
+RUN: ld.lld -### -m i386pe foo.o -enable-reloc-section -disable-reloc-section 2>&1 | FileCheck -check-prefix DISABLE-RELOC-SECTION %s
+RUN: ld.lld -### -m i386pe foo.o --enable-reloc-section --disable-reloc-section 2>&1 | FileCheck -check-prefix DISABLE-RELOC-SECTION %s
+DISABLE-RELOC-SECTION: -fixed{{ }}
+RUN: ld.lld -### -m i386pe foo.o -disable-reloc-section -enable-reloc-section 2>&1 | FileCheck -check-prefix NO-DISABLE-RELOC-SECTION %s
+RUN: ld.lld -### -m i386pe foo.o --disable-reloc-section --enable-reloc-section 2>&1 | FileCheck -check-prefix NO-DISABLE-RELOC-SECTION %s
+NO-DISABLE-RELOC-SECTION-NOT: -fixed
+
 RUN: ld.lld -### -m i386pep foo.o --image-base 0x1230000 2>&1 | FileCheck -check-prefix IMAGE-BASE %s
 RUN: ld.lld -### -m i386pep foo.o -image-base 0x1230000 2>&1 | FileCheck -check-prefix IMAGE-BASE %s
 RUN: ld.lld -### -m i386pep foo.o --image-base=0x1230000 2>&1 | FileCheck -check-prefix IMAGE-BASE %s
 IMAGE-BASE: -base:0x1230000
 
 RUN: ld.lld -### -m i386pep foo.o 2>&1 | FileCheck -check-prefix NO-GC-SECTIONS %s
 RUN: ld.lld -### -m i386pep foo.o --gc-sections --no-gc-sections 2>&1 | FileCheck -check-prefix NO-GC-SECTIONS %s
 NO-GC-SECTIONS: -opt:noref