[lldb] Stop passing both i386 and i686 in parallel as architectures on Windows

[mstorsjo]

Summary

When an object file returns multiple architectures, it is treated
as a fat binary - which really isn't the case of i386 vs i686 where
the object file actually has one architecture.

This allows getting rid of hardcoded architecture triples in
PlatformWindows.

The parallel i386 and i686 architecture strings stem from
5e6f45201f0b62c1e7a24fc396f3ea6e10dc880d / D7120 and
ad587ae4ca143d388c0ec4ef2faa1b5eddedbf67 / D4658.

[labath]

Thanks for cleaning this up.

lldb/source/Plugins/ObjectFile/PDB/ObjectFilePDB.cpp

size_t ObjectFilePDB::GetModuleSpecifications(
   switch (dbi_stream->getMachineType()) {
   case PDB_Machine::Amd64:
     module_arch.SetTriple("x86_64-pc-windows");
     specs.Append(module_spec);
     break;
   case PDB_Machine::x86:
     module_arch.SetTriple("i386-pc-windows");
     specs.Append(module_spec);
-    module_arch.SetTriple("i686-pc-windows");
-    specs.Append(module_spec);
     break;
   case PDB_Machine::ArmNT:
     module_arch.SetTriple("armv7-pc-windows");
     specs.Append(module_spec);
     break;
   case PDB_Machine::Arm64:
     module_arch.SetTriple("aarch64-pc-windows");
     specs.Append(module_spec);

lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp

case MachineAmd64:
     spec.SetTriple("x86_64-pc-windows");
     spec.GetTriple().setEnvironment(env);
     specs.Append(module_spec);
     break;
   case MachineX86:
     spec.SetTriple("i386-pc-windows");
     spec.GetTriple().setEnvironment(env);
     specs.Append(module_spec);
-    spec.SetTriple("i686-pc-windows");
-    spec.GetTriple().setEnvironment(env);
-    specs.Append(module_spec);
     break;
   case MachineArmNt:
     spec.SetTriple("armv7-pc-windows");
     spec.GetTriple().setEnvironment(env);
     specs.Append(module_spec);
     break;
   case MachineArm64:
     spec.SetTriple("aarch64-pc-windows");

lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp

PlatformWindows::PlatformWindows(bool is_host) : RemoteAwarePlatform(is_host) {
   const auto &AddArch = [&](const ArchSpec &spec) {
     if (llvm::any_of(m_supported_architectures, [spec](const ArchSpec &rhs) {
           return spec.IsExactMatch(rhs);
         }))
       return;
     if (spec.IsValid())
       m_supported_architectures.push_back(spec);
   };
-  AddArch(ArchSpec("i686-pc-windows"));
   AddArch(HostInfo::GetArchitecture(HostInfo::eArchKindDefault));
   AddArch(HostInfo::GetArchitecture(HostInfo::eArchKind32));
   AddArch(HostInfo::GetArchitecture(HostInfo::eArchKind64));
-  AddArch(ArchSpec("i386-pc-windows"));
 }
 
 Status PlatformWindows::ConnectRemote(Args &args) {
   Status error;
   if (IsHost()) {
     error.SetErrorStringWithFormatv(
         "can't connect to the host platform '{0}', always connected",
         GetPluginName());

lldb/test/Shell/ObjectFile/PECOFF/settings-abi-i686.yaml

 # RUN:   FileCheck -DABI=msvc -DFILENAME=%basename_t.tmp %s
 
 ## Default ABI is gnu:
 # RUN: %lldb -O "settings set plugin.object-file.pe-coff.abi gnu" \
 # RUN:   -f %t -o "image list --triple --basename" -o exit | \
 # RUN:   FileCheck -DABI=gnu -DFILENAME=%basename_t.tmp %s
 
 # CHECK-LABEL: image list --triple --basename
-# CHECK-NEXT: i686-pc-windows-[[ABI]] [[FILENAME]]
+# CHECK-NEXT: i386-pc-windows-[[ABI]] [[FILENAME]]
 
 --- !COFF
 OptionalHeader:
   AddressOfEntryPoint: 4480
   ImageBase:       268435456
   SectionAlignment: 4096
   FileAlignment:   512
   MajorOperatingSystemVersion: 6