Commit 99578e828b
Changed files (2)
src
link
src/link/MachO/commands.zig
@@ -7,11 +7,7 @@ const macho = std.macho;
const testing = std.testing;
const Allocator = std.mem.Allocator;
-const MachO = @import("../MachO.zig");
-const makeName = MachO.makeStaticString;
-const alloc_num = MachO.alloc_num;
-const alloc_den = MachO.alloc_den;
-const satMul = MachO.satMul;
+const makeStaticString = @import("../MachO.zig").makeStaticString;
pub const LoadCommand = union(enum) {
Segment: SegmentCommand,
@@ -153,7 +149,6 @@ pub const LoadCommand = union(enum) {
pub const SegmentCommand = struct {
inner: macho.segment_command_64,
- header_pad: ?u64 = null,
sections: std.ArrayListUnmanaged(macho.section_64) = .{},
pub fn empty(inner: macho.segment_command_64) SegmentCommand {
@@ -166,26 +161,6 @@ pub const SegmentCommand = struct {
self.inner.nsects += 1;
}
- fn detectAllocCollision(self: SegmentCommand, start: u64, size: u64) ?u64 {
- const end = start + satMul(size, alloc_num) / alloc_den;
- for (self.sections.items) |section| {
- const increased_size = satMul(section.size, alloc_num) / alloc_den;
- const test_end = section.offset + increased_size;
- if (end > section.offset and start < test_end) {
- return test_end;
- }
- }
- return null;
- }
-
- pub fn findFreeSpace(self: SegmentCommand, object_size: u64, min_alignment: u16) u32 {
- var start: u64 = if (self.header_pad) |pad| pad else 0;
- while (self.detectAllocCollision(start, object_size)) |item_end| {
- start = mem.alignForwardGeneric(u64, item_end, min_alignment);
- }
- return @intCast(u32, start);
- }
-
pub fn read(alloc: *Allocator, reader: anytype) !SegmentCommand {
const inner = try reader.readStruct(macho.segment_command_64);
var segment = SegmentCommand{
@@ -308,7 +283,7 @@ test "read-write segment command" {
.inner = .{
.cmd = macho.LC_SEGMENT_64,
.cmdsize = 152,
- .segname = makeName("__TEXT"),
+ .segname = makeStaticString("__TEXT"),
.vmaddr = 4294967296,
.vmsize = 294912,
.fileoff = 0,
@@ -320,8 +295,8 @@ test "read-write segment command" {
},
};
try cmd.sections.append(gpa, .{
- .sectname = makeName("__text"),
- .segname = makeName("__TEXT"),
+ .sectname = makeStaticString("__text"),
+ .segname = makeStaticString("__TEXT"),
.addr = 4294983680,
.size = 448,
.offset = 16384,
src/link/MachO.zig
@@ -152,8 +152,8 @@ pub const PieFixup = struct {
};
/// `alloc_num / alloc_den` is the factor of padding when allocating.
-pub const alloc_num = 4;
-pub const alloc_den = 3;
+const alloc_num = 4;
+const alloc_den = 3;
/// Default path to dyld
/// TODO instead of hardcoding it, we should probably look through some env vars and search paths
@@ -1305,21 +1305,21 @@ pub fn populateMissingMetadata(self: *MachO) !void {
log.debug("found __TEXT segment free space 0x{x} to 0x{x}\n", .{ 0, needed_size });
- var segment = SegmentCommand.empty(.{
- .cmd = macho.LC_SEGMENT_64,
- .cmdsize = @sizeOf(macho.segment_command_64),
- .segname = makeStaticString("__TEXT"),
- .vmaddr = 0x100000000, // always starts at 4GB
- .vmsize = needed_size,
- .fileoff = 0,
- .filesize = needed_size,
- .maxprot = maxprot,
- .initprot = initprot,
- .nsects = 0,
- .flags = 0,
+ try self.load_commands.append(self.base.allocator, .{
+ .Segment = SegmentCommand.empty(.{
+ .cmd = macho.LC_SEGMENT_64,
+ .cmdsize = @sizeOf(macho.segment_command_64),
+ .segname = makeStaticString("__TEXT"),
+ .vmaddr = 0x100000000, // always starts at 4GB
+ .vmsize = needed_size,
+ .fileoff = 0,
+ .filesize = needed_size,
+ .maxprot = maxprot,
+ .initprot = initprot,
+ .nsects = 0,
+ .flags = 0,
+ }),
});
- segment.header_pad = self.header_pad;
- try self.load_commands.append(self.base.allocator, .{ .Segment = segment });
self.cmd_table_dirty = true;
}
if (self.text_section_index == null) {
@@ -1333,7 +1333,7 @@ pub fn populateMissingMetadata(self: *MachO) !void {
};
const flags = macho.S_REGULAR | macho.S_ATTR_PURE_INSTRUCTIONS | macho.S_ATTR_SOME_INSTRUCTIONS;
const needed_size = self.base.options.program_code_size_hint;
- const off = text_segment.findFreeSpace(needed_size, @as(u16, 1) << alignment);
+ const off = self.findFreeSpace(text_segment, needed_size, @as(u16, 1) << alignment);
log.debug("found __text section free space 0x{x} to 0x{x}\n", .{ off, off + needed_size });
@@ -1342,7 +1342,7 @@ pub fn populateMissingMetadata(self: *MachO) !void {
.segname = makeStaticString("__TEXT"),
.addr = text_segment.inner.vmaddr + off,
.size = @intCast(u32, needed_size),
- .offset = off,
+ .offset = @intCast(u32, off),
.@"align" = alignment,
.reloff = 0,
.nreloc = 0,
@@ -1360,10 +1360,8 @@ pub fn populateMissingMetadata(self: *MachO) !void {
const flags = macho.S_REGULAR | macho.S_ATTR_PURE_INSTRUCTIONS | macho.S_ATTR_SOME_INSTRUCTIONS;
const needed_size = @sizeOf(u64) * self.base.options.symbol_count_hint;
- const off = text_segment.findFreeSpace(needed_size, @sizeOf(u64));
-
- // TODO Audit this. Is it possible to not find free space? We need to grow __TEXT then.
- assert(off + needed_size <= text_segment.inner.fileoff + text_segment.inner.filesize);
+ const off = self.findFreeSpace(text_segment, needed_size, @sizeOf(u64));
+ assert(off + needed_size <= text_segment.inner.fileoff + text_segment.inner.filesize); // TODO Must expand __TEXT segment.
log.debug("found __ziggot section free space 0x{x} to 0x{x}\n", .{ off, off + needed_size });
@@ -1372,7 +1370,7 @@ pub fn populateMissingMetadata(self: *MachO) !void {
.segname = makeStaticString("__TEXT"),
.addr = text_segment.inner.vmaddr + off,
.size = needed_size,
- .offset = off,
+ .offset = @intCast(u32, off),
.@"align" = @sizeOf(u64),
.reloff = 0,
.nreloc = 0,
@@ -1725,6 +1723,32 @@ fn nextSegmentAddressAndOffset(self: *MachO) NextSegmentAddressAndOffset {
};
}
+fn detectAllocCollision(self: *MachO, segment: *const SegmentCommand, start: u64, size: u64) ?u64 {
+ const end = start + satMul(size, alloc_num) / alloc_den;
+ for (segment.sections.items) |section| {
+ const increased_size = satMul(section.size, alloc_num) / alloc_den;
+ const test_end = section.offset + increased_size;
+ if (end > section.offset and start < test_end) {
+ return test_end;
+ }
+ }
+ return null;
+}
+
+fn findFreeSpace(self: *MachO, segment: *const SegmentCommand, object_size: u64, min_alignment: u16) u64 {
+ var start: u64 = if (parseAndCmpName(&segment.inner.segname, "__TEXT")) self.header_pad else 0;
+ while (self.detectAllocCollision(segment, start, object_size)) |item_end| {
+ start = mem.alignForwardGeneric(u64, item_end, min_alignment);
+ }
+ return start;
+}
+
+/// Saturating multiplication
+fn satMul(a: anytype, b: anytype) @TypeOf(a, b) {
+ const T = @TypeOf(a, b);
+ return std.math.mul(T, a, b) catch std.math.maxInt(T);
+}
+
fn writeOffsetTableEntry(self: *MachO, index: usize) !void {
const text_semgent = &self.load_commands.items[self.text_segment_cmd_index.?].Segment;
const sect = &text_semgent.sections.items[self.got_section_index.?];
@@ -2140,9 +2164,3 @@ fn parseLazyBindingInfoTable(self: *MachO) !void {
var stream = std.io.fixedBufferStream(buffer);
try self.lazy_binding_info_table.read(stream.reader(), self.base.allocator);
}
-
-/// Saturating multiplication
-pub fn satMul(a: anytype, b: anytype) @TypeOf(a, b) {
- const T = @TypeOf(a, b);
- return std.math.mul(T, a, b) catch std.math.maxInt(T);
-}