[lld-macho] Make load relaxation work for arm64_32

[int3]

Summary

arm64_32 uses 32-bit GOT loads, so we should accept those
instructions in ARM64Common::relaxGotLoad() too.

[gkm]

LGTM

lld/test/MachO/arm64-32-reloc-got-load.s

2

Super nitty: this and the original arm64-reloc-got-load.s have some tabs, and even some whitespace only differences between them.

For that matter, these 16 test files have some tabs:

./x86-64-reloc-got-load.s
./why-load.s
./arm64-relocs.s
./arm64-reloc-pointer-to-got.s
./weak-reference.s
./objc.s
./invalid/bad-got-to-dylib-tlv-reference.s
./invalid/bad-tlv-def.s
./invalid/bad-tlv-opcode.s
./weak-binding.s
./indirect-symtab.s
./tlv-dylib.s
./arm64-32-reloc-got-load.s
./mattrs.ll
./arm64-reloc-got-load.s
./tlv.s

28

The original arm64-reloc-got-load.s had this comment appended to the line: ; literal pool symbol address: _foo

30

The original arm64-reloc-got-load.s had this comment appended to the line: ; literal pool symbol address: _bar

[int3]

lld/test/MachO/arm64-32-reloc-got-load.s

2

good point. I've cleaned up the rest here: https://github.com/llvm/llvm-project/commit/74283fc8534b729f5e15ae934de15c01fd6db9c0

28

unfortunately llvm-objdump doesn't emit those comments for arm64_32

lld/MachO/Arch/ARM64Common.cpp

 
 void ARM64Common::relaxGotLoad(uint8_t *loc, uint8_t type) const {
   // The instruction format comments below are quoted from
   // Arm® Architecture Reference Manual
   // Armv8, for Armv8-A architecture profile
   // ARM DDI 0487G.a (ID011921)
   uint32_t instruction = read32le(loc);
   // C6.2.132 LDR (immediate)
-  // LDR <Xt>, [<Xn|SP>{, #<pimm>}]
-  if ((instruction & 0xffc00000) != 0xf9400000)
+  // This matches both the 64- and 32-bit variants:
+  // LDR <(X|W)t>, [<Xn|SP>{, #<pimm>}]
+  if ((instruction & 0xbfc00000) != 0xb9400000)
     error(getRelocAttrs(type).name + " reloc requires LDR instruction");
   assert(((instruction >> 10) & 0xfff) == 0 &&
          "non-zero embedded LDR immediate");
   // C6.2.4 ADD (immediate)
   // ADD <Xd|SP>, <Xn|SP>, #<imm>{, <shift>}
   instruction = ((instruction & 0x001fffff) | 0x91000000);
   write32le(loc, instruction);
 }

lld/test/MachO/arm64-32-reloc-got-load.s

+# REQUIRES: aarch64
+
+# RUN: rm -rf %t; split-file %s %t
+# RUN: llvm-mc -filetype=obj -triple=arm64_32-apple-darwin %t/main.s -o %t/main.o
+# RUN: llvm-mc -filetype=obj -triple=arm64_32-apple-darwin %t/foobar.s -o %t/foobar.o
+
+# RUN: %lld-watchos -lSystem -arch arm64_32 -o %t/static %t/main.o %t/foobar.o
+# RUN: llvm-objdump --macho -d --no-show-raw-insn --syms %t/static | FileCheck %s --check-prefix=STATIC
+
+# RUN: %lld-watchos -lSystem -arch arm64_32 -dylib -o %t/libfoo.dylib %t/foobar.o
+# RUN: %lld-watchos -lSystem -arch arm64_32 -o %t/main %t/main.o %t/libfoo.dylib
+# RUN: llvm-objdump --macho -d --no-show-raw-insn --section-headers %t/main | FileCheck %s --check-prefix=DYLIB
+
+# STATIC-LABEL: _main:
+# STATIC-NEXT:  adrp x8, [[#]] ; 0x[[#%x,PAGE:]]
+# STATIC-NEXT:  add  x8, x8, #[[#%u,FOO_OFF:]]
+# STATIC-NEXT:  adrp x8, [[#]] ; 0x[[#PAGE]]
+# STATIC-NEXT:  add  x8, x8, #[[#%u,BAR_OFF:]]
+# STATIC-NEXT:  ret
+
+# STATIC-LABEL: SYMBOL TABLE:
+# STATIC-DAG:   {{0*}}[[#%x,PAGE+FOO_OFF]] g     F __TEXT,__text _foo
+# STATIC-DAG:   {{0*}}[[#%x,PAGE+BAR_OFF]] g     F __TEXT,__text _bar
+
+# DYLIB-LABEL: _main:
+# DYLIB-NEXT:  adrp x8, [[#]] ; 0x[[#%x,GOT:]]
+# DYLIB-NEXT:  ldr  w8, [x8, #4]
+# DYLIB-NEXT:  adrp x8, [[#]] ; 0x[[#GOT]]
+# DYLIB-NEXT:  ldr  w8, [x8]
+# DYLIB-NEXT:  ret
+# DYLIB-NEXT:  Sections:
+# DYLIB-NEXT:  Idx   Name   Size      VMA            Type
+# DYLIB:       [[#]] __got  00000008  [[#%.8x,GOT]]  DATA
+
+#--- main.s
+.globl _main, _foo, _bar
+.p2align 2
+_main:
+  adrp x8, _foo@GOTPAGE
+  ldr  w8, [x8, _foo@GOTPAGEOFF]
+  adrp x8, _bar@GOTPAGE
+  ldr  w8, [x8, _bar@GOTPAGEOFF]
+  ret
+
+#--- foobar.s
+.globl _foo, _bar
+_foo:
+_bar: