[MC][COFF][AArch64] Treat ARM64EC/X as ARM64 for relocations (#86019)

Since ARM64EC/X objects use regular ARM64 relocations, any special
handling must be done for them too.

Author: bylaws

llvm/lib/MC/WinCOFFObjectWriter.cpp

@@ -266,7 +266,7 @@ WinCOFFWriter::WinCOFFWriter(WinCOFFObjectWriter &OWriter,
   // limited range for the immediate offset (+/- 1 MB); create extra offset
   // label symbols with regular intervals to allow referencing a
   // non-temporary symbol that is close enough.
-  UseOffsetLabels = Header.Machine == COFF::IMAGE_FILE_MACHINE_ARM64;
+  UseOffsetLabels = COFF::isAnyArm64(Header.Machine);
 }
 
 COFFSymbol *WinCOFFWriter::createSymbol(StringRef Name) {
@@ -954,7 +954,7 @@ void WinCOFFWriter::recordRelocation(MCAssembler &Asm,
        Reloc.Data.Type == COFF::IMAGE_REL_I386_REL32) ||
       (Header.Machine == COFF::IMAGE_FILE_MACHINE_ARMNT &&
        Reloc.Data.Type == COFF::IMAGE_REL_ARM_REL32) ||
-      (Header.Machine == COFF::IMAGE_FILE_MACHINE_ARM64 &&
+      (COFF::isAnyArm64(Header.Machine) &&
        Reloc.Data.Type == COFF::IMAGE_REL_ARM64_REL32))
     FixedValue += 4;
 

llvm/test/MC/AArch64/coff-relocations.s

@@ -1,7 +1,11 @@
 // RUN: llvm-mc -triple aarch64-windows -filetype obj -o %t.obj %s
-// RUN: llvm-readobj -r %t.obj | FileCheck %s
+// RUN: llvm-mc -triple arm64ec-windows -filetype obj -o %t-ec.obj %s
+// RUN: llvm-readobj -r %t.obj | FileCheck %s --check-prefixes=CHECK,CHECK-ARM64
+// RUN: llvm-readobj -r %t-ec.obj | FileCheck %s --check-prefixes=CHECK,CHECK-ARM64EC
 // RUN: llvm-objdump --no-print-imm-hex -d %t.obj | FileCheck %s --check-prefix=DISASM
+// RUN: llvm-objdump --no-print-imm-hex -d %t-ec.obj | FileCheck %s --check-prefix=DISASM
 // RUN: llvm-objdump -s %t.obj | FileCheck %s --check-prefix=DATA
+// RUN: llvm-objdump -s %t-ec.obj | FileCheck %s --check-prefix=DATA
 
 // IMAGE_REL_ARM64_ADDR32
 .Linfo_foo:
@@ -71,8 +75,10 @@ tbz x0, #0, target
 // IMAGE_REL_ARM64_REL32 because IMAGE_REL_ARM64_REL64 does not exist.
 .xword .Linfo_foo - .Ltable
 
-// CHECK: Format: COFF-ARM64
-// CHECK: Arch: aarch64
+// CHECK-ARM64: Format: COFF-ARM64
+// CHECK-ARM64EC: Format: COFF-ARM64EC
+// CHECK-ARM64: Arch: aarch64
+// CHECK-ARM64EC: Arch: aarch64
 // CHECK: AddressSize: 64bit
 // CHECK: Relocations [
 // CHECK:   Section (1) .text {