link: introduce common set of aarch64 abstractions

4 files changed, 24 insertions, 107 deletions

diff --git a/src/link/MachO/Atom.zig b/src/link/MachO/Atom.zig
index 98e0b0c4b6..2c3f360ec2 100644
--- a/src/link/MachO/Atom.zig
+++ b/src/link/MachO/Atom.zig
@@ -699,14 +699,7 @@ fn resolveRelocInner(
                         const S_: i64 = @intCast(thunk.getTargetAddress(rel.target, macho_file));
                         break :blk math.cast(i28, S_ + A - P) orelse return error.Overflow;
                     };
-                    var inst = aarch64.Instruction{
-                        .unconditional_branch_immediate = mem.bytesToValue(std.meta.TagPayload(
-                            aarch64.Instruction,
-                            aarch64.Instruction.unconditional_branch_immediate,
-                        ), code[rel_offset..][0..4]),
-                    };
-                    inst.unconditional_branch_immediate.imm26 = @as(u26, @truncate(@as(u28, @bitCast(disp >> 2))));
-                    try writer.writeInt(u32, inst.toU32(), .little);
+                    try aarch64.writeBranchImm(disp, code[rel_offset..][0..4]);
                 },
                 else => unreachable,
             }
@@ -776,16 +769,8 @@ fn resolveRelocInner(
                 };
                 break :target math.cast(u64, target) orelse return error.Overflow;
             };
-            const pages = @as(u21, @bitCast(try Relocation.calcNumberOfPages(source, target)));
-            var inst = aarch64.Instruction{
-                .pc_relative_address = mem.bytesToValue(std.meta.TagPayload(
-                    aarch64.Instruction,
-                    aarch64.Instruction.pc_relative_address,
-                ), code[rel_offset..][0..4]),
-            };
-            inst.pc_relative_address.immhi = @as(u19, @truncate(pages >> 2));
-            inst.pc_relative_address.immlo = @as(u2, @truncate(pages));
-            try writer.writeInt(u32, inst.toU32(), .little);
+            const pages = @as(u21, @bitCast(try aarch64.calcNumberOfPages(source, target)));
+            try aarch64.writePages(pages, code[rel_offset..][0..4]);
         },
 
         .pageoff => {
@@ -794,35 +779,8 @@ fn resolveRelocInner(
             assert(!rel.meta.pcrel);
             const target = math.cast(u64, S + A) orelse return error.Overflow;
             const inst_code = code[rel_offset..][0..4];
-            if (Relocation.isArithmeticOp(inst_code)) {
-                const off = try Relocation.calcPageOffset(target, .arithmetic);
-                var inst = aarch64.Instruction{
-                    .add_subtract_immediate = mem.bytesToValue(std.meta.TagPayload(
-                        aarch64.Instruction,
-                        aarch64.Instruction.add_subtract_immediate,
-                    ), inst_code),
-                };
-                inst.add_subtract_immediate.imm12 = off;
-                try writer.writeInt(u32, inst.toU32(), .little);
-            } else {
-                var inst = aarch64.Instruction{
-                    .load_store_register = mem.bytesToValue(std.meta.TagPayload(
-                        aarch64.Instruction,
-                        aarch64.Instruction.load_store_register,
-                    ), inst_code),
-                };
-                const off = try Relocation.calcPageOffset(target, switch (inst.load_store_register.size) {
-                    0 => if (inst.load_store_register.v == 1)
-                        Relocation.PageOffsetInstKind.load_store_128
-                    else
-                        Relocation.PageOffsetInstKind.load_store_8,
-                    1 => .load_store_16,
-                    2 => .load_store_32,
-                    3 => .load_store_64,
-                });
-                inst.load_store_register.offset = off;
-                try writer.writeInt(u32, inst.toU32(), .little);
-            }
+            const kind = aarch64.classifyInst(inst_code);
+            try aarch64.writePageOffset(kind, target, inst_code);
         },
 
         .got_load_pageoff => {
@@ -830,15 +788,7 @@ fn resolveRelocInner(
             assert(rel.meta.length == 2);
             assert(!rel.meta.pcrel);
             const target = math.cast(u64, G + A) orelse return error.Overflow;
-            const off = try Relocation.calcPageOffset(target, .load_store_64);
-            var inst: aarch64.Instruction = .{
-                .load_store_register = mem.bytesToValue(std.meta.TagPayload(
-                    aarch64.Instruction,
-                    aarch64.Instruction.load_store_register,
-                ), code[rel_offset..][0..4]),
-            };
-            inst.load_store_register.offset = off;
-            try writer.writeInt(u32, inst.toU32(), .little);
+            try aarch64.writePageOffset(.load_store_64, target, code[rel_offset..][0..4]);
         },
 
         .tlvp_pageoff => {
@@ -863,7 +813,7 @@ fn resolveRelocInner(
 
             const inst_code = code[rel_offset..][0..4];
             const reg_info: RegInfo = blk: {
-                if (Relocation.isArithmeticOp(inst_code)) {
+                if (aarch64.isArithmeticOp(inst_code)) {
                     const inst = mem.bytesToValue(std.meta.TagPayload(
                         aarch64.Instruction,
                         aarch64.Instruction.add_subtract_immediate,
@@ -890,7 +840,7 @@ fn resolveRelocInner(
                 .load_store_register = .{
                     .rt = reg_info.rd,
                     .rn = reg_info.rn,
-                    .offset = try Relocation.calcPageOffset(target, .load_store_64),
+                    .offset = try aarch64.calcPageOffset(.load_store_64, target),
                     .opc = 0b01,
                     .op1 = 0b01,
                     .v = 0,
@@ -900,7 +850,7 @@ fn resolveRelocInner(
                 .add_subtract_immediate = .{
                     .rd = reg_info.rd,
                     .rn = reg_info.rn,
-                    .imm12 = try Relocation.calcPageOffset(target, .arithmetic),
+                    .imm12 = try aarch64.calcPageOffset(.arithmetic, target),
                     .sh = 0,
                     .s = 0,
                     .op = 0,
@@ -1183,7 +1133,7 @@ pub const Loc = struct {
 
 pub const Alignment = @import("../../InternPool.zig").Alignment;
 
-const aarch64 = @import("../../arch/aarch64/bits.zig");
+const aarch64 = @import("../aarch64.zig");
 const assert = std.debug.assert;
 const bind = @import("dyld_info/bind.zig");
 const macho = std.macho;
diff --git a/src/link/MachO/Relocation.zig b/src/link/MachO/Relocation.zig
index e350684eac..2df9355de9 100644
--- a/src/link/MachO/Relocation.zig
+++ b/src/link/MachO/Relocation.zig
@@ -60,38 +60,6 @@ pub fn lessThan(ctx: void, lhs: Relocation, rhs: Relocation) bool {
     return lhs.offset < rhs.offset;
 }
 
-pub fn calcNumberOfPages(saddr: u64, taddr: u64) error{Overflow}!i21 {
-    const spage = math.cast(i32, saddr >> 12) orelse return error.Overflow;
-    const tpage = math.cast(i32, taddr >> 12) orelse return error.Overflow;
-    const pages = math.cast(i21, tpage - spage) orelse return error.Overflow;
-    return pages;
-}
-
-pub const PageOffsetInstKind = enum {
-    arithmetic,
-    load_store_8,
-    load_store_16,
-    load_store_32,
-    load_store_64,
-    load_store_128,
-};
-
-pub fn calcPageOffset(taddr: u64, kind: PageOffsetInstKind) !u12 {
-    const narrowed = @as(u12, @truncate(taddr));
-    return switch (kind) {
-        .arithmetic, .load_store_8 => narrowed,
-        .load_store_16 => try math.divExact(u12, narrowed, 2),
-        .load_store_32 => try math.divExact(u12, narrowed, 4),
-        .load_store_64 => try math.divExact(u12, narrowed, 8),
-        .load_store_128 => try math.divExact(u12, narrowed, 16),
-    };
-}
-
-pub inline fn isArithmeticOp(inst: *const [4]u8) bool {
-    const group_decode = @as(u5, @truncate(inst[3]));
-    return ((group_decode >> 2) == 4);
-}
-
 pub const Type = enum {
     // x86_64
     /// RIP-relative displacement (X86_64_RELOC_SIGNED)
diff --git a/src/link/MachO/synthetic.zig b/src/link/MachO/synthetic.zig
index 774fbe0d27..0536026633 100644
--- a/src/link/MachO/synthetic.zig
+++ b/src/link/MachO/synthetic.zig
@@ -267,9 +267,9 @@ pub const StubsSection = struct {
                 },
                 .aarch64 => {
                     // TODO relax if possible
-                    const pages = try Relocation.calcNumberOfPages(source, target);
+                    const pages = try aarch64.calcNumberOfPages(source, target);
                     try writer.writeInt(u32, aarch64.Instruction.adrp(.x16, pages).toU32(), .little);
-                    const off = try Relocation.calcPageOffset(target, .load_store_64);
+                    const off = try aarch64.calcPageOffset(.load_store_64, target);
                     try writer.writeInt(
                         u32,
                         aarch64.Instruction.ldr(.x16, .x16, aarch64.Instruction.LoadStoreOffset.imm(off)).toU32(),
@@ -411,9 +411,9 @@ pub const StubsHelperSection = struct {
             .aarch64 => {
                 {
                     // TODO relax if possible
-                    const pages = try Relocation.calcNumberOfPages(sect.addr, dyld_private_addr);
+                    const pages = try aarch64.calcNumberOfPages(sect.addr, dyld_private_addr);
                     try writer.writeInt(u32, aarch64.Instruction.adrp(.x17, pages).toU32(), .little);
-                    const off = try Relocation.calcPageOffset(dyld_private_addr, .arithmetic);
+                    const off = try aarch64.calcPageOffset(.arithmetic, dyld_private_addr);
                     try writer.writeInt(u32, aarch64.Instruction.add(.x17, .x17, off, false).toU32(), .little);
                 }
                 try writer.writeInt(u32, aarch64.Instruction.stp(
@@ -424,9 +424,9 @@ pub const StubsHelperSection = struct {
                 ).toU32(), .little);
                 {
                     // TODO relax if possible
-                    const pages = try Relocation.calcNumberOfPages(sect.addr + 12, dyld_stub_binder_addr);
+                    const pages = try aarch64.calcNumberOfPages(sect.addr + 12, dyld_stub_binder_addr);
                     try writer.writeInt(u32, aarch64.Instruction.adrp(.x16, pages).toU32(), .little);
-                    const off = try Relocation.calcPageOffset(dyld_stub_binder_addr, .load_store_64);
+                    const off = try aarch64.calcPageOffset(.load_store_64, dyld_stub_binder_addr);
                     try writer.writeInt(u32, aarch64.Instruction.ldr(
                         .x16,
                         .x16,
@@ -679,9 +679,9 @@ pub const ObjcStubsSection = struct {
                     {
                         const target = sym.getObjcSelrefsAddress(macho_file);
                         const source = addr;
-                        const pages = try Relocation.calcNumberOfPages(source, target);
+                        const pages = try aarch64.calcNumberOfPages(source, target);
                         try writer.writeInt(u32, aarch64.Instruction.adrp(.x1, pages).toU32(), .little);
-                        const off = try Relocation.calcPageOffset(target, .load_store_64);
+                        const off = try aarch64.calcPageOffset(.load_store_64, target);
                         try writer.writeInt(
                             u32,
                             aarch64.Instruction.ldr(.x1, .x1, aarch64.Instruction.LoadStoreOffset.imm(off)).toU32(),
@@ -692,9 +692,9 @@ pub const ObjcStubsSection = struct {
                         const target_sym = macho_file.getSymbol(macho_file.objc_msg_send_index.?);
                         const target = target_sym.getGotAddress(macho_file);
                         const source = addr + 2 * @sizeOf(u32);
-                        const pages = try Relocation.calcNumberOfPages(source, target);
+                        const pages = try aarch64.calcNumberOfPages(source, target);
                         try writer.writeInt(u32, aarch64.Instruction.adrp(.x16, pages).toU32(), .little);
-                        const off = try Relocation.calcPageOffset(target, .load_store_64);
+                        const off = try aarch64.calcPageOffset(.load_store_64, target);
                         try writer.writeInt(
                             u32,
                             aarch64.Instruction.ldr(.x16, .x16, aarch64.Instruction.LoadStoreOffset.imm(off)).toU32(),
@@ -778,7 +778,7 @@ pub const WeakBindSection = bind.WeakBind;
 pub const LazyBindSection = bind.LazyBind;
 pub const ExportTrieSection = Trie;
 
-const aarch64 = @import("../../arch/aarch64/bits.zig");
+const aarch64 = @import("../aarch64.zig");
 const assert = std.debug.assert;
 const bind = @import("dyld_info/bind.zig");
 const math = std.math;
@@ -788,6 +788,5 @@ const trace = @import("../../tracy.zig").trace;
 const Allocator = std.mem.Allocator;
 const MachO = @import("../MachO.zig");
 const Rebase = @import("dyld_info/Rebase.zig");
-const Relocation = @import("Relocation.zig");
 const Symbol = @import("Symbol.zig");
 const Trie = @import("dyld_info/Trie.zig");
diff --git a/src/link/MachO/thunks.zig b/src/link/MachO/thunks.zig
index cd9ea20c86..e3f98c655c 100644
--- a/src/link/MachO/thunks.zig
+++ b/src/link/MachO/thunks.zig
@@ -99,9 +99,9 @@ pub const Thunk = struct {
             const sym = macho_file.getSymbol(sym_index);
             const saddr = thunk.getAddress(macho_file) + i * trampoline_size;
             const taddr = sym.getAddress(.{}, macho_file);
-            const pages = try Relocation.calcNumberOfPages(saddr, taddr);
+            const pages = try aarch64.calcNumberOfPages(saddr, taddr);
             try writer.writeInt(u32, aarch64.Instruction.adrp(.x16, pages).toU32(), .little);
-            const off = try Relocation.calcPageOffset(taddr, .arithmetic);
+            const off = try aarch64.calcPageOffset(.arithmetic, taddr);
             try writer.writeInt(u32, aarch64.Instruction.add(.x16, .x16, off, false).toU32(), .little);
             try writer.writeInt(u32, aarch64.Instruction.br(.x16).toU32(), .little);
         }
@@ -164,7 +164,7 @@ const max_distance = (1 << (jump_bits - 1));
 /// and assume margin to be 5MiB.
 const max_allowed_distance = max_distance - 0x500_000;
 
-const aarch64 = @import("../../arch/aarch64/bits.zig");
+const aarch64 = @import("../aarch64.zig");
 const assert = std.debug.assert;
 const log = std.log.scoped(.link);
 const macho = std.macho;