[lld] Use correct machine type in ARM64EC COFF headers.

[jacek]

Summary

This adds very minimal support for ARM64EC/ARM64X targets, just enough for interesting test cases. Next patches in the series extend llvm-objdump and llvm-readobj to provide better tests. Those will also be useful for testing further ARM64EC LLD support.

[mstorsjo]

lld/test/COFF/arm64ec.test

12

Is it possible to add a check for arm64x too, or is harder to create such object files?

15

It’sa bit unclear what the DATAEC check here really verifies? I’m sure it’s relevant later on, but within the scope of this patch, this test feels mostly confusing.

[mstorsjo]

lld/test/COFF/arm64ec.test

15

Nevermind, for both comments here - it becomes quite reasonable in the next patch, and it's probably cleanest to leave this as is.

[jacek]

I changed tests to include ARM64X input object, which also allowed testing ARM64X headers in this patch. I also moved data tests to the next patch, where it makes more sense.

[mstorsjo]

LGTM, thanks!

lld/COFF/Chunks.cpp

case AMD64:
     break;
   case I386:
     applyRelX86(off, rel.Type, os, s, p, imageBase);
     break;
   case ARMNT:
     applyRelARM(off, rel.Type, os, s, p, imageBase);
     break;
   case ARM64:
+  case ARM64EC:
+  case ARM64X:
     applyRelARM64(off, rel.Type, os, s, p, imageBase);
     break;
   default:
     llvm_unreachable("unknown machine type");
   }
 }
 
 // Defend against unsorted relocations. This may be overly conservative.
case I386:
     return IMAGE_REL_BASED_ABSOLUTE;
   case ARMNT:
     if (rel.Type == IMAGE_REL_ARM_ADDR32)
       return IMAGE_REL_BASED_HIGHLOW;
     if (rel.Type == IMAGE_REL_ARM_MOV32T)
       return IMAGE_REL_BASED_ARM_MOV32T;
     return IMAGE_REL_BASED_ABSOLUTE;
   case ARM64:
+  case ARM64EC:
+  case ARM64X:
     if (rel.Type == IMAGE_REL_ARM64_ADDR64)
       return IMAGE_REL_BASED_DIR64;
     return IMAGE_REL_BASED_ABSOLUTE;
   default:
     llvm_unreachable("unknown machine type");
   }
 }
 

lld/COFF/Config.h

 class StringChunk;
 class Symbol;
 class InputFile;
 class SectionChunk;
 
 // Short aliases.
 static const auto AMD64 = llvm::COFF::IMAGE_FILE_MACHINE_AMD64;
 static const auto ARM64 = llvm::COFF::IMAGE_FILE_MACHINE_ARM64;
+static const auto ARM64EC = llvm::COFF::IMAGE_FILE_MACHINE_ARM64EC;
+static const auto ARM64X = llvm::COFF::IMAGE_FILE_MACHINE_ARM64X;
 static const auto ARMNT = llvm::COFF::IMAGE_FILE_MACHINE_ARMNT;
 static const auto I386 = llvm::COFF::IMAGE_FILE_MACHINE_I386;
 
 // Represents an /export option.
 struct Export {
   StringRef name;       // N in /export:N or /export:E=N
   StringRef extName;    // E in /export:E=N
   StringRef aliasTarget; // GNU specific: N in "alias == N"
enum class ICFLevel {
   Safe, // Safe ICF for all sections.
   All,  // Aggressive ICF for code, but safe ICF for data, similar to MSVC's
         // behavior.
 };
 
 // Global configuration.
 struct Configuration {
   enum ManifestKind { Default, SideBySide, Embed, No };
-  bool is64() const { return machine == AMD64 || machine == ARM64; }
+  bool is64() const {
+    return machine == AMD64 || llvm::COFF::isAnyArm64(machine);
+  }
 
   llvm::COFF::MachineTypes machine = IMAGE_FILE_MACHINE_UNKNOWN;
   size_t wordsize;
   bool verbose = false;
   WindowsSubsystem subsystem = llvm::COFF::IMAGE_SUBSYSTEM_UNKNOWN;
   Symbol *entry = nullptr;
   bool noEntry = false;
   std::string outputFile;

lld/COFF/Writer.cpp

template <typename PEHeaderTy> void Writer::writeHeader() {
 
   // Write PE magic
   memcpy(buf, PEMagic, sizeof(PEMagic));
   buf += sizeof(PEMagic);
 
   // Write COFF header
   auto *coff = reinterpret_cast<coff_file_header *>(buf);
   buf += sizeof(*coff);
+  switch (config->machine) {
+  case ARM64EC:
+    coff->Machine = AMD64;
+    break;
+  case ARM64X:
+    coff->Machine = ARM64;
+    break;
+  default:
     coff->Machine = config->machine;
+  }
   coff->NumberOfSections = ctx.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;

lld/test/COFF/arm64ec.test

+REQUIRES: aarch64
+RUN: split-file %s %t.dir && cd %t.dir
+
+RUN: llvm-mc -filetype=obj -triple=arm64ec-windows arm64ec-data-sym.s -o arm64ec-data-sym.obj
+RUN: llvm-cvtres -machine:arm64x -out:arm64x-resource.obj %S/Inputs/resource.res
+
+RUN: lld-link -out:test.dll -machine:arm64ec arm64ec-data-sym.obj -dll -noentry
+RUN: llvm-readobj --file-headers test.dll | FileCheck -check-prefix=ARM64EC-HEADER %s
+ARM64EC-HEADER:      Format: COFF-x86-64
+ARM64EC-HEADER-NEXT: Arch: x86_64
+ARM64EC-HEADER-NEXT: AddressSize: 64bit
+ARM64EC-HEADER:      Machine: IMAGE_FILE_MACHINE_AMD64 (0x8664)
+
+RUN: lld-link -out:test.dll -machine:arm64x arm64x-resource.obj -dll -noentry
+RUN: llvm-readobj --file-headers test.dll | FileCheck -check-prefix=ARM64X-HEADER %s
+ARM64X-HEADER:      Machine: IMAGE_FILE_MACHINE_ARM64 (0xAA64)
+
+#--- arm64ec-data-sym.s
+    .data
+    .globl arm64ec_data_sym
+    .p2align 2, 0x0
+arm64ec_data_sym:
+    .word 0x02020202