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x64+aarch64: check for pointer to zero-bit type when lowering decl

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Unless the pointer is a pointer to a function, if the pointee type
has zero-bits, we need to return `MCValue.none` as the `Decl` has
not been lowered to memory, and therefore, any GOT reference will be
wrong.
This commit is contained in:
Jakub Konka 2022-02-25 21:53:46 +01:00
parent 4b14384989
commit e0f5627d4a
6 changed files with 27 additions and 4 deletions
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10
src/arch/aarch64/CodeGen.zig
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@ -3550,6 +3550,15 @@ fn getResolvedInstValue(self: *Self, inst: Air.Inst.Index) MCValue {
fn lowerDeclRef(self: *Self, tv: TypedValue, decl: *Module.Decl) InnerError!MCValue {
const ptr_bits = self.target.cpu.arch.ptrBitWidth();
const ptr_bytes: u64 = @divExact(ptr_bits, 8);
// TODO this feels clunky. Perhaps we should check for it in `genTypedValue`?
if (tv.ty.zigTypeTag() == .Pointer) blk: {
if (tv.ty.castPtrToFn()) |_| break :blk;
if (!tv.ty.elemType2().hasRuntimeBits()) {
return MCValue.none;
}
}
decl.alive = true;
if (self.bin_file.cast(link.File.Elf)) |elf_file| {
const got = &elf_file.program_headers.items[elf_file.phdr_got_index.?];
@ -3558,6 +3567,7 @@ fn lowerDeclRef(self: *Self, tv: TypedValue, decl: *Module.Decl) InnerError!MCVa
} else if (self.bin_file.cast(link.File.MachO)) |_| {
// Because MachO is PIE-always-on, we defer memory address resolution until
// the linker has enough info to perform relocations.
assert(decl.link.macho.local_sym_index != 0);
return MCValue{ .got_load = decl.link.macho.local_sym_index };
} else if (self.bin_file.cast(link.File.Coff)) |coff_file| {
const got_addr = coff_file.offset_table_virtual_address + decl.link.coff.offset_table_index * ptr_bytes;

9
src/arch/x86_64/CodeGen.zig
View File

@ -5333,6 +5333,14 @@ fn lowerDeclRef(self: *Self, tv: TypedValue, decl: *Module.Decl) InnerError!MCVa
const ptr_bits = self.target.cpu.arch.ptrBitWidth();
const ptr_bytes: u64 = @divExact(ptr_bits, 8);
// TODO this feels clunky. Perhaps we should check for it in `genTypedValue`?
if (tv.ty.zigTypeTag() == .Pointer) blk: {
if (tv.ty.castPtrToFn()) |_| break :blk;
if (!tv.ty.elemType2().hasRuntimeBits()) {
return MCValue.none;
}
}
decl.alive = true;
if (self.bin_file.cast(link.File.Elf)) |elf_file| {
const got = &elf_file.program_headers.items[elf_file.phdr_got_index.?];
@ -5341,6 +5349,7 @@ fn lowerDeclRef(self: *Self, tv: TypedValue, decl: *Module.Decl) InnerError!MCVa
} else if (self.bin_file.cast(link.File.MachO)) |_| {
// Because MachO is PIE-always-on, we defer memory address resolution until
// the linker has enough info to perform relocations.
assert(decl.link.macho.local_sym_index != 0);
return MCValue{ .got_load = decl.link.macho.local_sym_index };
} else if (self.bin_file.cast(link.File.Coff)) |coff_file| {
const got_addr = coff_file.offset_table_virtual_address + decl.link.coff.offset_table_index * ptr_bytes;

1
src/arch/x86_64/Emit.zig
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@ -857,6 +857,7 @@ fn mirLeaPie(emit: *Emit, inst: Mir.Inst.Index) InnerError!void {
else => return emit.fail("TODO unused LEA PIE variants 0b10 and 0b11", .{}),
};
const atom = macho_file.atom_by_index_table.get(load_reloc.atom_index).?;
log.debug("adding reloc of type {} to local @{d}", .{ reloc_type, load_reloc.sym_index });
try atom.relocs.append(emit.bin_file.allocator, .{
.offset = @intCast(u32, end_offset - 4),
.target = .{ .local = load_reloc.sym_index },

7
src/link/MachO.zig
View File

@ -4286,6 +4286,7 @@ pub fn deleteExport(self: *MachO, exp: Export) void {
}
fn freeUnnamedConsts(self: *MachO, decl: *Module.Decl) void {
log.debug("freeUnnamedConsts for decl {*}", .{decl});
const unnamed_consts = self.unnamed_const_atoms.getPtr(decl) orelse return;
for (unnamed_consts.items) |atom| {
self.freeAtom(atom, .{
@ -4295,6 +4296,7 @@ fn freeUnnamedConsts(self: *MachO, decl: *Module.Decl) void {
self.locals_free_list.append(self.base.allocator, atom.local_sym_index) catch {};
self.locals.items[atom.local_sym_index].n_type = 0;
_ = self.atom_by_index_table.remove(atom.local_sym_index);
log.debug(" adding local symbol index {d} to free list", .{atom.local_sym_index});
atom.local_sym_index = 0;
}
unnamed_consts.clearAndFree(self.base.allocator);
@ -4319,10 +4321,15 @@ pub fn freeDecl(self: *MachO, decl: *Module.Decl) void {
self.got_entries_free_list.append(self.base.allocator, @intCast(u32, got_index)) catch {};
self.got_entries.items[got_index] = .{ .target = .{ .local = 0 }, .atom = undefined };
_ = self.got_entries_table.swapRemove(.{ .local = decl.link.macho.local_sym_index });
log.debug(" adding GOT index {d} to free list (target local@{d})", .{
got_index,
decl.link.macho.local_sym_index,
});
}
self.locals.items[decl.link.macho.local_sym_index].n_type = 0;
_ = self.atom_by_index_table.remove(decl.link.macho.local_sym_index);
log.debug(" adding local symbol index {d} to free list", .{decl.link.macho.local_sym_index});
decl.link.macho.local_sym_index = 0;
}
if (self.d_sym) |*d_sym| {

2
test/behavior/basic.zig
View File

@ -399,8 +399,6 @@ fn testTakeAddressOfParameter(f: f32) !void {
test "pointer to void return type" {
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64 and builtin.os.tag == .macos) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_x86_64 and builtin.os.tag == .macos) return error.SkipZigTest;
try testPointerToVoidReturnType();
}

2
test/behavior/struct.zig
View File

@ -370,8 +370,6 @@ test "empty struct method call" {
if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64 and builtin.os.tag == .macos) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_x86_64 and builtin.os.tag == .macos) return error.SkipZigTest; // TODO
const es = EmptyStruct{};
try expect(es.method() == 1234);