From dc6480dba5ec4533f6a20292f93fe5c25a1a689f Mon Sep 17 00:00:00 2001
From: Jakub Konka <kubkon@jakubkonka.com>
Date: Thu, 15 Sep 2022 22:02:40 +0200
Subject: [PATCH] macho: allow for add and ldr when resolving GOT_LOAD_* relocs

---
 src/arch/aarch64/Emit.zig     |  5 +++--
 src/link/MachO.zig            |  1 +
 src/link/MachO/Relocation.zig | 33 +++++++--------------------------
 3 files changed, 11 insertions(+), 28 deletions(-)

diff --git a/src/arch/aarch64/Emit.zig b/src/arch/aarch64/Emit.zig
index a868b74edc..5e1e1c7135 100644
--- a/src/arch/aarch64/Emit.zig
+++ b/src/arch/aarch64/Emit.zig
@@ -845,7 +845,8 @@ fn mirLoadMemoryPie(emit: *Emit, inst: Mir.Inst.Index) !void {
     try emit.writeInstruction(Instruction.adrp(reg.to64(), 0));
 
     switch (tag) {
-        .load_memory_got => {
+        .load_memory_got,
+        => {
             // ldr reg, reg, offset
             try emit.writeInstruction(Instruction.ldr(
                 reg,
@@ -871,8 +872,8 @@ fn mirLoadMemoryPie(emit: *Emit, inst: Mir.Inst.Index) !void {
                 Instruction.LoadStoreOffset.imm(0),
             ));
         },
-        .load_memory_ptr_got,
         .load_memory_ptr_direct,
+        .load_memory_ptr_got,
         => {
             // add reg, reg, offset
             try emit.writeInstruction(Instruction.add(reg, reg, 0, false));
diff --git a/src/link/MachO.zig b/src/link/MachO.zig
index 2b7a3d43ae..2e21aa1af9 100644
--- a/src/link/MachO.zig
+++ b/src/link/MachO.zig
@@ -3434,6 +3434,7 @@ pub fn populateMissingMetadata(self: *MachO) !void {
     }
 
     if (self.text_section_index == null) {
+        // Sadly, segments need unique string identfiers for some reason.
         self.text_section_index = try self.allocateSection("__TEXT1", "__text", .{
             .size = self.base.options.program_code_size_hint,
             .alignment = switch (cpu_arch) {
diff --git a/src/link/MachO/Relocation.zig b/src/link/MachO/Relocation.zig
index 2b68051c5b..1acbb30a24 100644
--- a/src/link/MachO/Relocation.zig
+++ b/src/link/MachO/Relocation.zig
@@ -135,7 +135,9 @@ fn resolveAarch64(
             inst.pc_relative_address.immlo = @truncate(u2, pages);
             mem.writeIntLittle(u32, &buffer, inst.toU32());
         },
-        .ARM64_RELOC_PAGEOFF12 => {
+        .ARM64_RELOC_PAGEOFF12,
+        .ARM64_RELOC_GOT_LOAD_PAGEOFF12,
+        => {
             const narrowed = @truncate(u12, @intCast(u64, target_addr));
             if (isArithmeticOp(&buffer)) {
                 var inst = aarch64.Instruction{
@@ -170,18 +172,6 @@ fn resolveAarch64(
                 mem.writeIntLittle(u32, &buffer, inst.toU32());
             }
         },
-        .ARM64_RELOC_GOT_LOAD_PAGEOFF12 => {
-            const narrowed = @truncate(u12, @intCast(u64, target_addr));
-            var inst: aarch64.Instruction = .{
-                .load_store_register = mem.bytesToValue(meta.TagPayload(
-                    aarch64.Instruction,
-                    aarch64.Instruction.load_store_register,
-                ), &buffer),
-            };
-            const offset = @divExact(narrowed, 8);
-            inst.load_store_register.offset = offset;
-            mem.writeIntLittle(u32, &buffer, inst.toU32());
-        },
         .ARM64_RELOC_TLVP_LOAD_PAGEOFF12 => {
             const RegInfo = struct {
                 rd: u5,
@@ -226,11 +216,8 @@ fn resolveAarch64(
             mem.writeIntLittle(u32, &buffer, inst.toU32());
         },
         .ARM64_RELOC_POINTER_TO_GOT => {
-            const result = math.cast(
-                i32,
-                @intCast(i64, target_addr) - @intCast(i64, source_addr),
-            ) orelse return error.Overflow;
-            mem.writeIntLittle(u32, &buffer, @bitCast(u32, result));
+            const result = @intCast(i32, @intCast(i64, target_addr) - @intCast(i64, source_addr));
+            mem.writeIntLittle(i32, &buffer, result);
         },
         .ARM64_RELOC_SUBTRACTOR => unreachable,
         .ARM64_RELOC_ADDEND => unreachable,
@@ -255,10 +242,7 @@ fn resolveX8664(
             .X86_64_RELOC_GOT_LOAD,
             .X86_64_RELOC_TLV,
             => {
-                const displacement = math.cast(
-                    i32,
-                    @intCast(i64, target_addr) - @intCast(i64, source_addr) - 4,
-                ) orelse return error.Overflow;
+                const displacement = @intCast(i32, @intCast(i64, target_addr) - @intCast(i64, source_addr) - 4);
                 mem.writeIntLittle(u32, buffer[0..4], @bitCast(u32, displacement));
                 break :blk buffer[0..4];
             },
@@ -274,10 +258,7 @@ fn resolveX8664(
                     .X86_64_RELOC_SIGNED_4 => 4,
                     else => unreachable,
                 };
-                const displacement = math.cast(
-                    i32,
-                    target_addr - @intCast(i64, source_addr + correction + 4),
-                ) orelse return error.Overflow;
+                const displacement = @intCast(i32, target_addr - @intCast(i64, source_addr + correction + 4));
                 mem.writeIntLittle(u32, buffer[0..4], @bitCast(u32, displacement));
                 break :blk buffer[0..4];
             },