macho+coff: remove alignment from Atom as it is unused

src/link/Coff.zig

@@ -155,6 +155,7 @@ const LazySymbolTable = std.ArrayHashMapUnmanaged(
 const LazySymbolMetadata = struct {
     atom: Atom.Index,
     section: u16,
+    alignment: u32,
 };
 
 const DeclMetadata = struct {
@@ -625,7 +626,6 @@ fn allocateAtom(self: *Coff, atom_index: Atom.Index, new_atom_size: u32, alignme
     {
         const atom_ptr = self.getAtomPtr(atom_index);
         atom_ptr.size = new_atom_size;
-        atom_ptr.alignment = alignment;
     }
 
     if (atom.prev_index) |prev_index| {
@@ -739,7 +739,6 @@ pub fn createAtom(self: *Coff) !Atom.Index {
         .sym_index = sym_index,
         .file = null,
         .size = 0,
-        .alignment = 0,
         .prev_index = null,
         .next_index = null,
     };
@@ -751,11 +750,10 @@ fn createGotAtom(self: *Coff, target: SymbolWithLoc) !Atom.Index {
     const atom_index = try self.createAtom();
     const atom = self.getAtomPtr(atom_index);
     atom.size = @sizeOf(u64);
-    atom.alignment = @alignOf(u64);
 
     const sym = atom.getSymbolPtr(self);
     sym.section_number = @intToEnum(coff.SectionNumber, self.got_section_index.? + 1);
-    sym.value = try self.allocateAtom(atom_index, atom.size, atom.alignment);
+    sym.value = try self.allocateAtom(atom_index, atom.size, @sizeOf(u64));
 
     log.debug("allocated GOT atom at 0x{x}", .{sym.value});
 
@@ -1116,9 +1114,8 @@ pub fn lowerUnnamedConst(self: *Coff, tv: TypedValue, decl_index: Module.Decl.In
 
     const required_alignment = tv.ty.abiAlignment(self.base.options.target);
     const atom = self.getAtomPtr(atom_index);
-    atom.alignment = required_alignment;
     atom.size = @intCast(u32, code.len);
-    atom.getSymbolPtr(self).value = try self.allocateAtom(atom_index, atom.size, atom.alignment);
+    atom.getSymbolPtr(self).value = try self.allocateAtom(atom_index, atom.size, required_alignment);
     errdefer self.freeAtom(atom_index);
 
     try unnamed_consts.append(gpa, atom_index);
@@ -1228,7 +1225,7 @@ fn updateLazySymbol(
         },
     };
 
-    const required_alignment = atom.alignment;
+    const required_alignment = lazy_metadata.alignment;
     const code_len = @intCast(u32, code.len);
     const symbol = atom.getSymbolPtr(self);
     try self.setSymbolName(symbol, name);
@@ -1271,8 +1268,8 @@ pub fn getOrCreateAtomForLazySymbol(
                 .code => self.text_section_index.?,
                 .const_data => self.rdata_section_index.?,
             },
+            .alignment = alignment,
         };
-        self.getAtomPtr(gop.value_ptr.atom).alignment = alignment;
     }
     return gop.value_ptr.atom;
 }

src/link/Coff/Atom.zig

@@ -19,12 +19,9 @@ sym_index: u32,
 /// null means symbol defined by Zig source.
 file: ?u32,
 
-/// Used size of the atom
+/// Size of the atom
 size: u32,
 
-/// Alignment of the atom
-alignment: u32,
-
 /// Points to the previous and next neighbors, based on the `text_offset`.
 /// This can be used to find, for example, the capacity of this `Atom`.
 prev_index: ?Index,

src/link/MachO.zig

@@ -242,6 +242,7 @@ const LazySymbolTable = std.ArrayHashMapUnmanaged(
 const LazySymbolMetadata = struct {
     atom: Atom.Index,
     section: u8,
+    alignment: u32,
 };
 
 const DeclMetadata = struct {
@@ -1205,7 +1206,6 @@ pub fn createAtom(self: *MachO) !Atom.Index {
         .sym_index = sym_index,
         .file = null,
         .size = 0,
-        .alignment = 0,
         .prev_index = null,
         .next_index = null,
     };
@@ -1217,7 +1217,6 @@ pub fn createGotAtom(self: *MachO, target: SymbolWithLoc) !Atom.Index {
     const atom_index = try self.createAtom();
     const atom = self.getAtomPtr(atom_index);
     atom.size = @sizeOf(u64);
-    atom.alignment = @alignOf(u64);
 
     const sym = atom.getSymbolPtr(self);
     sym.n_type = macho.N_SECT;
@@ -1259,7 +1258,6 @@ pub fn createDyldPrivateAtom(self: *MachO) !void {
     const atom_index = try self.createAtom();
     const atom = self.getAtomPtr(atom_index);
     atom.size = @sizeOf(u64);
-    atom.alignment = @alignOf(u64);
 
     const sym = atom.getSymbolPtr(self);
     sym.n_type = macho.N_SECT;
@@ -1285,7 +1283,8 @@ pub fn createStubHelperPreambleAtom(self: *MachO) !void {
     const atom_index = try self.createAtom();
     const atom = self.getAtomPtr(atom_index);
     atom.size = size;
-    atom.alignment = switch (arch) {
+
+    const required_alignment: u32 = switch (arch) {
         .x86_64 => 1,
         .aarch64 => @alignOf(u32),
         else => unreachable,
@@ -1392,7 +1391,7 @@ pub fn createStubHelperPreambleAtom(self: *MachO) !void {
     }
     self.stub_helper_preamble_atom_index = atom_index;
 
-    sym.n_value = try self.allocateAtom(atom_index, size, atom.alignment);
+    sym.n_value = try self.allocateAtom(atom_index, size, required_alignment);
     log.debug("allocated stub preamble atom at 0x{x}", .{sym.n_value});
     try self.writeAtom(atom_index, code);
 }
@@ -1408,7 +1407,8 @@ pub fn createStubHelperAtom(self: *MachO) !Atom.Index {
     const atom_index = try self.createAtom();
     const atom = self.getAtomPtr(atom_index);
     atom.size = size;
-    atom.alignment = switch (arch) {
+
+    const required_alignment: u32 = switch (arch) {
         .x86_64 => 1,
         .aarch64 => @alignOf(u32),
         else => unreachable,
@@ -1470,7 +1470,7 @@ pub fn createStubHelperAtom(self: *MachO) !Atom.Index {
         else => unreachable,
     }
 
-    sym.n_value = try self.allocateAtom(atom_index, size, atom.alignment);
+    sym.n_value = try self.allocateAtom(atom_index, size, required_alignment);
     log.debug("allocated stub helper atom at 0x{x}", .{sym.n_value});
     try self.writeAtom(atom_index, code);
 
@@ -1481,7 +1481,6 @@ pub fn createLazyPointerAtom(self: *MachO, stub_sym_index: u32, target: SymbolWi
     const atom_index = try self.createAtom();
     const atom = self.getAtomPtr(atom_index);
     atom.size = @sizeOf(u64);
-    atom.alignment = @alignOf(u64);
 
     const sym = atom.getSymbolPtr(self);
     sym.n_type = macho.N_SECT;
@@ -1523,7 +1522,8 @@ pub fn createStubAtom(self: *MachO, laptr_sym_index: u32) !Atom.Index {
     const atom_index = try self.createAtom();
     const atom = self.getAtomPtr(atom_index);
     atom.size = size;
-    atom.alignment = switch (arch) {
+
+    const required_alignment: u32 = switch (arch) {
         .x86_64 => 1,
         .aarch64 => @alignOf(u32),
         else => unreachable, // unhandled architecture type
@@ -1587,7 +1587,7 @@ pub fn createStubAtom(self: *MachO, laptr_sym_index: u32) !Atom.Index {
         else => unreachable,
     }
 
-    sym.n_value = try self.allocateAtom(atom_index, size, atom.alignment);
+    sym.n_value = try self.allocateAtom(atom_index, size, required_alignment);
     log.debug("allocated stub atom at 0x{x}", .{sym.n_value});
     try self.writeAtom(atom_index, code);
 
@@ -2217,7 +2217,6 @@ pub fn lowerUnnamedConst(self: *MachO, typed_value: TypedValue, decl_index: Modu
     const required_alignment = typed_value.ty.abiAlignment(self.base.options.target);
     const atom = self.getAtomPtr(atom_index);
     atom.size = code.len;
-    atom.alignment = required_alignment;
     // TODO: work out logic for disambiguating functions from function pointers
     // const sect_id = self.getDeclOutputSection(decl_index);
     const sect_id = self.data_const_section_index.?;
@@ -2355,7 +2354,7 @@ fn updateLazySymbol(self: *MachO, lazy_sym: File.LazySymbol, lazy_metadata: Lazy
         },
     };
 
-    const required_alignment = atom.alignment;
+    const required_alignment = lazy_metadata.alignment;
     const symbol = atom.getSymbolPtr(self);
     symbol.n_strx = name_str_index;
     symbol.n_type = macho.N_SECT;
@@ -2398,8 +2397,8 @@ pub fn getOrCreateAtomForLazySymbol(
                 .code => self.text_section_index.?,
                 .const_data => self.data_const_section_index.?,
             },
+            .alignment = alignment,
         };
-        self.getAtomPtr(gop.value_ptr.atom).alignment = alignment;
     }
     return gop.value_ptr.atom;
 }
@@ -3222,7 +3221,6 @@ fn allocateAtom(self: *MachO, atom_index: Atom.Index, new_atom_size: u64, alignm
     {
         const atom_ptr = self.getAtomPtr(atom_index);
         atom_ptr.size = new_atom_size;
-        atom_ptr.alignment = @intCast(u32, alignment);
     }
 
     if (atom.prev_index) |prev_index| {
@@ -4510,12 +4508,11 @@ pub fn logAtom(self: *MachO, atom_index: Atom.Index) void {
     const atom = self.getAtom(atom_index);
     const sym = atom.getSymbol(self);
     const sym_name = atom.getName(self);
-    log.debug("  ATOM(%{?d}, '{s}') @ {x} (sizeof({x}), alignof({x})) in object({?d}) in sect({d})", .{
+    log.debug("  ATOM(%{?d}, '{s}') @ {x} sizeof({x}) in object({?d}) in sect({d})", .{
         atom.getSymbolIndex(),
         sym_name,
         sym.n_value,
         atom.size,
-        atom.alignment,
         atom.file,
         sym.n_sect,
     });

src/link/MachO/Atom.zig

@@ -33,10 +33,6 @@ file: ?u32,
 /// the atom since macho.nlist_64 lacks this information.
 size: u64,
 
-/// Alignment of this atom as a power of 2.
-/// For instance, alignment of 0 should be read as 2^0 = 1 byte aligned.
-alignment: u32,
-
 /// Points to the previous and next neighbours
 /// TODO use the same trick as with symbols: reserve index 0 as null atom
 next_index: ?Index,