Implement /driver, /driver:wdm and /driver:uponly

[ruiu]

Summary

This patch implements /driver, /driver:wdm and /driver:uponly as
described in https://docs.microsoft.com/en-us/cpp/build/reference/driver-windows-nt-kernel-mode-driver?view=vs-2019.

[thakis]

Looks good, some suggestions on additional things that might be interesting to check below.

Did someone ask for this, or is this just for fun / completeness? (Either's fine of course, just curious)

lld/test/COFF/driver-opt.s

4

What does link.exe do with /fixed /driver and /driver /fixed?

20

What does link.exe say to /driver:uponly,wdm ?

[ruiu]

In D70162#1743489, @thakis wrote:

Looks good, some suggestions on additional things that might be interesting to check below.

Did someone ask for this, or is this just for fun / completeness? (Either's fine of course, just curious)

I wanted to add a warning for /driver for https://bugs.llvm.org/show_bug.cgi?id=43911
and then realized that /driver is not actually implemented. So this option may not be
something that people are actively using, but as long as we are going to print out a
warning message recommending /driver, I needed to implement the option.

[ruiu]

lld/test/COFF/driver-opt.s

20

link.exe handles it as /driver:uponly and /drivedr:wdm, so I implemented the same behavior.

lld/COFF/Config.h

struct Configuration {
   bool relocatable = true;
   bool forceMultiple = false;
   bool forceMultipleRes = false;
   bool forceUnresolved = false;
   bool debug = false;
   bool debugDwarf = false;
   bool debugGHashes = false;
   bool debugSymtab = false;
+  bool driver = false;
+  bool driverUponly = false;
+  bool driverWdm = false;
   bool showTiming = false;
   bool showSummary = false;
   unsigned debugTypes = static_cast<unsigned>(DebugType::None);
   std::vector<std::string> natvisFiles;
   llvm::SmallString<128> pdbAltPath;
   llvm::SmallString<128> pdbPath;
   llvm::SmallString<128> pdbSourcePath;
   std::vector<llvm::StringRef> argv;

lld/COFF/Driver.cpp

static std::pair<StringRef, StringRef> getOldNewOptions(opt::InputArgList &args,
 
   StringRef s = arg->getValue();
   std::pair<StringRef, StringRef> ret = s.split(';');
   if (ret.second.empty())
     error(arg->getSpelling() + " expects 'old;new' format, but got " + s);
   return ret;
 }
 
-// Drop directory components and replace extension with ".exe" or ".dll".
+// Drop directory components and replace extension with
+// ".exe", ".dll" or ".sys".
 static std::string getOutputPath(StringRef path) {
-  return (sys::path::stem(path) + (config->dll ? ".dll" : ".exe")).str();
+  StringRef ext = ".exe";
+  if (config->dll)
+    ext = ".dll";
+  else if (config->driver)
+    ext = ".sys";
+
+  return (sys::path::stem(path) + ext).str();
 }
 
 // Returns true if S matches /crtend.?\.o$/.
 static bool isCrtend(StringRef s) {
   if (!s.endswith(".o"))
     return false;
   s = s.drop_back(2);
   if (s.endswith("crtend"))
void LinkerDriver::link(ArrayRef<const char *> argsArr) {
   }
 
   // Handle /demangle
   config->demangle = args.hasFlag(OPT_demangle, OPT_demangle_no);
 
   // Handle /debugtype
   config->debugTypes = parseDebugTypes(args);
 
+  // Handle /driver[:uponly|wdm].
+  config->driverUponly = args.hasArg(OPT_driver_uponly);
+  config->driverWdm = args.hasArg(OPT_driver_wdm);
+  config->driver =
+      config->driverUponly || config->driverWdm || args.hasArg(OPT_driver);
+
   // Handle /pdb
   bool shouldCreatePDB =
       (debug == DebugKind::Full || debug == DebugKind::GHash);
   if (shouldCreatePDB) {
     if (auto *arg = args.getLastArg(OPT_pdb))
       config->pdbPath = arg->getValue();
     if (auto *arg = args.getLastArg(OPT_pdbaltpath))
       config->pdbAltPath = arg->getValue();
void LinkerDriver::link(ArrayRef<const char *> argsArr) {
   // Handle /entry and /dll
   if (auto *arg = args.getLastArg(OPT_entry)) {
     config->entry = addUndefined(mangle(arg->getValue()));
   } else if (!config->entry && !config->noEntry) {
     if (args.hasArg(OPT_dll)) {
       StringRef s = (config->machine == I386) ? "__DllMainCRTStartup@12"
                                               : "_DllMainCRTStartup";
       config->entry = addUndefined(s);
+    } else if (args.hasArg(OPT_driver_wdm)) {
+      // /driver:wdm implies /entry:_NtProcessStartup
+      config->entry = addUndefined(mangle("_NtProcessStartup"));
     } else {
       // Windows specific -- If entry point name is not given, we need to
       // infer that from user-defined entry name.
       StringRef s = findDefaultEntry();
       if (s.empty())
         fatal("entry point must be defined");
       config->entry = addUndefined(s);
       log("Entry name inferred: " + s);

lld/COFF/Options.td

 // "def" is also a keyword.
 def deffile : Joined<["/", "-", "/?", "-?"], "def:">,
     HelpText<"Use module-definition file">;
 
 def debug : F<"debug">, HelpText<"Embed a symbol table in the image">;
 def debug_opt : P<"debug", "Embed a symbol table in the image with option">;
 def debugtype : P<"debugtype", "Debug Info Options">;
 def dll : F<"dll">, HelpText<"Create a DLL">;
-def driver : P<"driver", "Generate a Windows NT Kernel Mode Driver">;
+def driver : F<"driver">, HelpText<"Generate a Windows NT Kernel Mode Driver">;
+def driver_wdm : F<"driver:wdm">,
+    HelpText<"Set IMAGE_FILE_UP_SYSTEM_ONLY bit in PE header">;
+def driver_uponly : F<"driver:uponly">,
+    HelpText<"Set IMAGE_DLL_CHARACTERISTICS_WDM_DRIVER bit in PE header">;
 def nodefaultlib_all : F<"nodefaultlib">,
     HelpText<"Remove all default libraries">;
 def noentry : F<"noentry">,
     HelpText<"Don't add reference to DllMainCRTStartup; only valid with /dll">;
 def profile : F<"profile">;
 def repro : F<"Brepro">,
     HelpText<"Use a hash of the executable as the PE header timestamp">;
 def reproduce : P<"reproduce",

lld/COFF/Writer.cpp

template <typename PEHeaderTy> void Writer::writeHeader() {
   coff->NumberOfSections = outputSections.size();
   coff->Characteristics = IMAGE_FILE_EXECUTABLE_IMAGE;
   if (config->largeAddressAware)
     coff->Characteristics |= IMAGE_FILE_LARGE_ADDRESS_AWARE;
   if (!config->is64())
     coff->Characteristics |= IMAGE_FILE_32BIT_MACHINE;
   if (config->dll)
     coff->Characteristics |= IMAGE_FILE_DLL;
+  if (config->driverUponly)
+    coff->Characteristics |= IMAGE_FILE_UP_SYSTEM_ONLY;
   if (!config->relocatable)
     coff->Characteristics |= IMAGE_FILE_RELOCS_STRIPPED;
   if (config->swaprunCD)
     coff->Characteristics |= IMAGE_FILE_REMOVABLE_RUN_FROM_SWAP;
   if (config->swaprunNet)
     coff->Characteristics |= IMAGE_FILE_NET_RUN_FROM_SWAP;
   coff->SizeOfOptionalHeader =
       sizeof(PEHeaderTy) + sizeof(data_directory) * numberOfDataDirectory;
if (config->machine == ARMNT)
       pe->AddressOfEntryPoint |= 1;
   }
   pe->SizeOfStackReserve = config->stackReserve;
   pe->SizeOfStackCommit = config->stackCommit;
   pe->SizeOfHeapReserve = config->heapReserve;
   pe->SizeOfHeapCommit = config->heapCommit;
   if (config->appContainer)
     pe->DLLCharacteristics |= IMAGE_DLL_CHARACTERISTICS_APPCONTAINER;
+  if (config->driverWdm)
+    pe->DLLCharacteristics |= IMAGE_DLL_CHARACTERISTICS_WDM_DRIVER;
   if (config->dynamicBase)
     pe->DLLCharacteristics |= IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE;
   if (config->highEntropyVA)
     pe->DLLCharacteristics |= IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA;
   if (!config->allowBind)
     pe->DLLCharacteristics |= IMAGE_DLL_CHARACTERISTICS_NO_BIND;
   if (config->nxCompat)
     pe->DLLCharacteristics |= IMAGE_DLL_CHARACTERISTICS_NX_COMPAT;

lld/test/COFF/driver-opt.s

+# RUN: mkdir -p %t.dir
+# RUN: yaml2obj < %s > %t.dir/foo.obj
+
+# RUN: rm -f %t.dir/foo.sys
+# RUN: cd %t.dir; lld-link /driver foo.obj
+# RUN: llvm-readobj --file-headers %t.dir/foo.sys | FileCheck -check-prefix=DRIVER %s
+
+# DRIVER-NOT: IMAGE_FILE_UP_SYSTEM_ONLY
+# DRIVER-NOT: IMAGE_DLL_CHARACTERISTICS_WDM_DRIVER
+# DRIVER: AddressOfEntryPoint: 0x1000
+
+# RUN: rm -f %t.dir/foo.sys
+# RUN: cd %t.dir; lld-link /driver:uponly foo.obj
+# RUN: llvm-readobj --file-headers %t.dir/foo.sys | FileCheck -check-prefix=UPONLY %s
+
+# UPONLY: IMAGE_FILE_UP_SYSTEM_ONLY
+# UPONLY: AddressOfEntryPoint: 0x1000
+
+# RUN: rm -f %t.dir/foo.sys
+# RUN: cd %t.dir; lld-link /driver:wdm foo.obj
+# RUN: llvm-readobj --file-headers %t.dir/foo.sys | FileCheck -check-prefix=WDM %s
+
+# WDM: AddressOfEntryPoint: 0x1004
+# WDM: IMAGE_DLL_CHARACTERISTICS_WDM_DRIVER
+
+--- !COFF
+header:
+  Machine:         IMAGE_FILE_MACHINE_AMD64
+  Characteristics: []
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    Alignment:       4096
+    SectionData:     0000000000000000
+    Relocations:
+      - VirtualAddress:  0
+        SymbolName:      __ImageBase
+        Type:            IMAGE_REL_AMD64_ADDR64
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          8
+      NumberOfRelocations: 1
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          0
+  - Name:            main
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            mainCRTStartup
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            _NtProcessStartup
+    Value:           4
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+...