zig/src/link/Coff.zig
Andrew Kelley accd5701c2 compiler: move struct types into InternPool proper
Structs were previously using `SegmentedList` to be given indexes, but
were not actually backed by the InternPool arrays.

After this, the only remaining uses of `SegmentedList` in the compiler
are `Module.Decl` and `Module.Namespace`. Once those last two are
migrated to become backed by InternPool arrays as well, we can introduce
state serialization via writing these arrays to disk all at once.

Unfortunately there are a lot of source code locations that touch the
struct type API, so this commit is still work-in-progress. Once I get it
compiling and passing the test suite, I can provide some interesting
data points such as how it affected the InternPool memory size and
performance comparison against master branch.

I also couldn't resist migrating over a bunch of alignment API over to
use the log2 Alignment type rather than a mismash of u32 and u64 byte
units with 0 meaning something implicitly different and special at every
location. Turns out you can do all the math you need directly on the
log2 representation of alignments.
2023-09-21 14:48:40 -07:00

2545 lines
94 KiB
Zig

//! The main driver of the COFF linker.
//! Currently uses our own implementation for the incremental linker, and falls back to
//! LLD for traditional linking (linking relocatable object files).
//! LLD is also the default linker for LLVM.
/// If this is not null, an object file is created by LLVM and linked with LLD afterwards.
llvm_object: ?*LlvmObject = null,
base: link.File,
error_flags: link.File.ErrorFlags = .{},
ptr_width: PtrWidth,
page_size: u32,
objects: std.ArrayListUnmanaged(Object) = .{},
sections: std.MultiArrayList(Section) = .{},
data_directories: [coff.IMAGE_NUMBEROF_DIRECTORY_ENTRIES]coff.ImageDataDirectory,
text_section_index: ?u16 = null,
got_section_index: ?u16 = null,
rdata_section_index: ?u16 = null,
data_section_index: ?u16 = null,
reloc_section_index: ?u16 = null,
idata_section_index: ?u16 = null,
locals: std.ArrayListUnmanaged(coff.Symbol) = .{},
globals: std.ArrayListUnmanaged(SymbolWithLoc) = .{},
resolver: std.StringHashMapUnmanaged(u32) = .{},
unresolved: std.AutoArrayHashMapUnmanaged(u32, bool) = .{},
locals_free_list: std.ArrayListUnmanaged(u32) = .{},
globals_free_list: std.ArrayListUnmanaged(u32) = .{},
strtab: StringTable(.strtab) = .{},
strtab_offset: ?u32 = null,
temp_strtab: StringTable(.temp_strtab) = .{},
got_table: TableSection(SymbolWithLoc) = .{},
/// A table of ImportTables partitioned by the library name.
/// Key is an offset into the interning string table `temp_strtab`.
import_tables: std.AutoArrayHashMapUnmanaged(u32, ImportTable) = .{},
got_table_count_dirty: bool = true,
got_table_contents_dirty: bool = true,
imports_count_dirty: bool = true,
/// Virtual address of the entry point procedure relative to image base.
entry_addr: ?u32 = null,
/// Table of tracked LazySymbols.
lazy_syms: LazySymbolTable = .{},
/// Table of tracked Decls.
decls: std.AutoArrayHashMapUnmanaged(Module.Decl.Index, DeclMetadata) = .{},
/// List of atoms that are either synthetic or map directly to the Zig source program.
atoms: std.ArrayListUnmanaged(Atom) = .{},
/// Table of atoms indexed by the symbol index.
atom_by_index_table: std.AutoHashMapUnmanaged(u32, Atom.Index) = .{},
/// Table of unnamed constants associated with a parent `Decl`.
/// We store them here so that we can free the constants whenever the `Decl`
/// needs updating or is freed.
///
/// For example,
///
/// ```zig
/// const Foo = struct{
/// a: u8,
/// };
///
/// pub fn main() void {
/// var foo = Foo{ .a = 1 };
/// _ = foo;
/// }
/// ```
///
/// value assigned to label `foo` is an unnamed constant belonging/associated
/// with `Decl` `main`, and lives as long as that `Decl`.
unnamed_const_atoms: UnnamedConstTable = .{},
/// A table of relocations indexed by the owning them `Atom`.
/// Note that once we refactor `Atom`'s lifetime and ownership rules,
/// this will be a table indexed by index into the list of Atoms.
relocs: RelocTable = .{},
/// A table of base relocations indexed by the owning them `Atom`.
/// Note that once we refactor `Atom`'s lifetime and ownership rules,
/// this will be a table indexed by index into the list of Atoms.
base_relocs: BaseRelocationTable = .{},
/// Hot-code swapping state.
hot_state: if (is_hot_update_compatible) HotUpdateState else struct {} = .{},
const is_hot_update_compatible = switch (builtin.target.os.tag) {
.windows => true,
else => false,
};
const HotUpdateState = struct {
/// Base address at which the process (image) got loaded.
/// We need this info to correctly slide pointers when relocating.
loaded_base_address: ?std.os.windows.HMODULE = null,
};
const RelocTable = std.AutoArrayHashMapUnmanaged(Atom.Index, std.ArrayListUnmanaged(Relocation));
const BaseRelocationTable = std.AutoArrayHashMapUnmanaged(Atom.Index, std.ArrayListUnmanaged(u32));
const UnnamedConstTable = std.AutoArrayHashMapUnmanaged(Module.Decl.Index, std.ArrayListUnmanaged(Atom.Index));
const default_file_alignment: u16 = 0x200;
const default_size_of_stack_reserve: u32 = 0x1000000;
const default_size_of_stack_commit: u32 = 0x1000;
const default_size_of_heap_reserve: u32 = 0x100000;
const default_size_of_heap_commit: u32 = 0x1000;
const Section = struct {
header: coff.SectionHeader,
last_atom_index: ?Atom.Index = null,
/// A list of atoms that have surplus capacity. This list can have false
/// positives, as functions grow and shrink over time, only sometimes being added
/// or removed from the freelist.
///
/// An atom has surplus capacity when its overcapacity value is greater than
/// padToIdeal(minimum_atom_size). That is, when it has so
/// much extra capacity, that we could fit a small new symbol in it, itself with
/// ideal_capacity or more.
///
/// Ideal capacity is defined by size + (size / ideal_factor).
///
/// Overcapacity is measured by actual_capacity - ideal_capacity. Note that
/// overcapacity can be negative. A simple way to have negative overcapacity is to
/// allocate a fresh atom, which will have ideal capacity, and then grow it
/// by 1 byte. It will then have -1 overcapacity.
free_list: std.ArrayListUnmanaged(Atom.Index) = .{},
};
const LazySymbolTable = std.AutoArrayHashMapUnmanaged(Module.Decl.OptionalIndex, LazySymbolMetadata);
const LazySymbolMetadata = struct {
const State = enum { unused, pending_flush, flushed };
text_atom: Atom.Index = undefined,
rdata_atom: Atom.Index = undefined,
text_state: State = .unused,
rdata_state: State = .unused,
};
const DeclMetadata = struct {
atom: Atom.Index,
section: u16,
/// A list of all exports aliases of this Decl.
exports: std.ArrayListUnmanaged(u32) = .{},
fn deinit(m: *DeclMetadata, allocator: Allocator) void {
m.exports.deinit(allocator);
}
fn getExport(m: DeclMetadata, coff_file: *const Coff, name: []const u8) ?u32 {
for (m.exports.items) |exp| {
if (mem.eql(u8, name, coff_file.getSymbolName(.{
.sym_index = exp,
.file = null,
}))) return exp;
}
return null;
}
fn getExportPtr(m: *DeclMetadata, coff_file: *Coff, name: []const u8) ?*u32 {
for (m.exports.items) |*exp| {
if (mem.eql(u8, name, coff_file.getSymbolName(.{
.sym_index = exp.*,
.file = null,
}))) return exp;
}
return null;
}
};
pub const PtrWidth = enum {
p32,
p64,
/// Size in bytes.
pub fn size(pw: PtrWidth) u4 {
return switch (pw) {
.p32 => 4,
.p64 => 8,
};
}
};
pub const SymbolWithLoc = struct {
// Index into the respective symbol table.
sym_index: u32,
// null means it's a synthetic global or Zig source.
file: ?u32 = null,
pub fn eql(this: SymbolWithLoc, other: SymbolWithLoc) bool {
if (this.file == null and other.file == null) {
return this.sym_index == other.sym_index;
}
if (this.file != null and other.file != null) {
return this.sym_index == other.sym_index and this.file.? == other.file.?;
}
return false;
}
};
/// When allocating, the ideal_capacity is calculated by
/// actual_capacity + (actual_capacity / ideal_factor)
const ideal_factor = 3;
/// In order for a slice of bytes to be considered eligible to keep metadata pointing at
/// it as a possible place to put new symbols, it must have enough room for this many bytes
/// (plus extra for reserved capacity).
const minimum_text_block_size = 64;
pub const min_text_capacity = padToIdeal(minimum_text_block_size);
pub fn openPath(allocator: Allocator, sub_path: []const u8, options: link.Options) !*Coff {
assert(options.target.ofmt == .coff);
if (options.use_llvm) {
return createEmpty(allocator, options);
}
const self = try createEmpty(allocator, options);
errdefer self.base.destroy();
const file = try options.emit.?.directory.handle.createFile(sub_path, .{
.truncate = false,
.read = true,
.mode = link.determineMode(options),
});
self.base.file = file;
try self.populateMissingMetadata();
return self;
}
pub fn createEmpty(gpa: Allocator, options: link.Options) !*Coff {
const ptr_width: PtrWidth = switch (options.target.ptrBitWidth()) {
0...32 => .p32,
33...64 => .p64,
else => return error.UnsupportedCOFFArchitecture,
};
const page_size: u32 = switch (options.target.cpu.arch) {
else => 0x1000,
};
const self = try gpa.create(Coff);
errdefer gpa.destroy(self);
self.* = .{
.base = .{
.tag = .coff,
.options = options,
.allocator = gpa,
.file = null,
},
.ptr_width = ptr_width,
.page_size = page_size,
.data_directories = comptime mem.zeroes([coff.IMAGE_NUMBEROF_DIRECTORY_ENTRIES]coff.ImageDataDirectory),
};
if (options.use_llvm) {
self.llvm_object = try LlvmObject.create(gpa, options);
}
return self;
}
pub fn deinit(self: *Coff) void {
const gpa = self.base.allocator;
if (self.llvm_object) |llvm_object| llvm_object.destroy(gpa);
for (self.objects.items) |*object| {
object.deinit(gpa);
}
self.objects.deinit(gpa);
for (self.sections.items(.free_list)) |*free_list| {
free_list.deinit(gpa);
}
self.sections.deinit(gpa);
self.atoms.deinit(gpa);
self.locals.deinit(gpa);
self.globals.deinit(gpa);
{
var it = self.resolver.keyIterator();
while (it.next()) |key_ptr| {
gpa.free(key_ptr.*);
}
self.resolver.deinit(gpa);
}
self.unresolved.deinit(gpa);
self.locals_free_list.deinit(gpa);
self.globals_free_list.deinit(gpa);
self.strtab.deinit(gpa);
self.temp_strtab.deinit(gpa);
self.got_table.deinit(gpa);
for (self.import_tables.values()) |*itab| {
itab.deinit(gpa);
}
self.import_tables.deinit(gpa);
for (self.decls.values()) |*metadata| {
metadata.deinit(gpa);
}
self.decls.deinit(gpa);
self.atom_by_index_table.deinit(gpa);
for (self.unnamed_const_atoms.values()) |*atoms| {
atoms.deinit(gpa);
}
self.unnamed_const_atoms.deinit(gpa);
for (self.relocs.values()) |*relocs| {
relocs.deinit(gpa);
}
self.relocs.deinit(gpa);
for (self.base_relocs.values()) |*relocs| {
relocs.deinit(gpa);
}
self.base_relocs.deinit(gpa);
}
fn populateMissingMetadata(self: *Coff) !void {
assert(self.llvm_object == null);
const gpa = self.base.allocator;
try self.strtab.buffer.ensureUnusedCapacity(gpa, @sizeOf(u32));
self.strtab.buffer.appendNTimesAssumeCapacity(0, @sizeOf(u32));
try self.temp_strtab.buffer.append(gpa, 0);
// Index 0 is always a null symbol.
try self.locals.append(gpa, .{
.name = [_]u8{0} ** 8,
.value = 0,
.section_number = .UNDEFINED,
.type = .{ .base_type = .NULL, .complex_type = .NULL },
.storage_class = .NULL,
.number_of_aux_symbols = 0,
});
if (self.text_section_index == null) {
const file_size = @as(u32, @intCast(self.base.options.program_code_size_hint));
self.text_section_index = try self.allocateSection(".text", file_size, .{
.CNT_CODE = 1,
.MEM_EXECUTE = 1,
.MEM_READ = 1,
});
}
if (self.got_section_index == null) {
const file_size = @as(u32, @intCast(self.base.options.symbol_count_hint)) * self.ptr_width.size();
self.got_section_index = try self.allocateSection(".got", file_size, .{
.CNT_INITIALIZED_DATA = 1,
.MEM_READ = 1,
});
}
if (self.rdata_section_index == null) {
const file_size: u32 = self.page_size;
self.rdata_section_index = try self.allocateSection(".rdata", file_size, .{
.CNT_INITIALIZED_DATA = 1,
.MEM_READ = 1,
});
}
if (self.data_section_index == null) {
const file_size: u32 = self.page_size;
self.data_section_index = try self.allocateSection(".data", file_size, .{
.CNT_INITIALIZED_DATA = 1,
.MEM_READ = 1,
.MEM_WRITE = 1,
});
}
if (self.idata_section_index == null) {
const file_size = @as(u32, @intCast(self.base.options.symbol_count_hint)) * self.ptr_width.size();
self.idata_section_index = try self.allocateSection(".idata", file_size, .{
.CNT_INITIALIZED_DATA = 1,
.MEM_READ = 1,
});
}
if (self.reloc_section_index == null) {
const file_size = @as(u32, @intCast(self.base.options.symbol_count_hint)) * @sizeOf(coff.BaseRelocation);
self.reloc_section_index = try self.allocateSection(".reloc", file_size, .{
.CNT_INITIALIZED_DATA = 1,
.MEM_DISCARDABLE = 1,
.MEM_READ = 1,
});
}
if (self.strtab_offset == null) {
const file_size = @as(u32, @intCast(self.strtab.len()));
self.strtab_offset = self.findFreeSpace(file_size, @alignOf(u32)); // 4bytes aligned seems like a good idea here
log.debug("found strtab free space 0x{x} to 0x{x}", .{ self.strtab_offset.?, self.strtab_offset.? + file_size });
}
{
// We need to find out what the max file offset is according to section headers.
// Otherwise, we may end up with an COFF binary with file size not matching the final section's
// offset + it's filesize.
// TODO I don't like this here one bit
var max_file_offset: u64 = 0;
for (self.sections.items(.header)) |header| {
if (header.pointer_to_raw_data + header.size_of_raw_data > max_file_offset) {
max_file_offset = header.pointer_to_raw_data + header.size_of_raw_data;
}
}
try self.base.file.?.pwriteAll(&[_]u8{0}, max_file_offset);
}
}
fn allocateSection(self: *Coff, name: []const u8, size: u32, flags: coff.SectionHeaderFlags) !u16 {
const index = @as(u16, @intCast(self.sections.slice().len));
const off = self.findFreeSpace(size, default_file_alignment);
// Memory is always allocated in sequence
// TODO: investigate if we can allocate .text last; this way it would never need to grow in memory!
const vaddr = blk: {
if (index == 0) break :blk self.page_size;
const prev_header = self.sections.items(.header)[index - 1];
break :blk mem.alignForward(u32, prev_header.virtual_address + prev_header.virtual_size, self.page_size);
};
// We commit more memory than needed upfront so that we don't have to reallocate too soon.
const memsz = mem.alignForward(u32, size, self.page_size) * 100;
log.debug("found {s} free space 0x{x} to 0x{x} (0x{x} - 0x{x})", .{
name,
off,
off + size,
vaddr,
vaddr + size,
});
var header = coff.SectionHeader{
.name = undefined,
.virtual_size = memsz,
.virtual_address = vaddr,
.size_of_raw_data = size,
.pointer_to_raw_data = off,
.pointer_to_relocations = 0,
.pointer_to_linenumbers = 0,
.number_of_relocations = 0,
.number_of_linenumbers = 0,
.flags = flags,
};
try self.setSectionName(&header, name);
try self.sections.append(self.base.allocator, .{ .header = header });
return index;
}
fn growSection(self: *Coff, sect_id: u32, needed_size: u32) !void {
const header = &self.sections.items(.header)[sect_id];
const maybe_last_atom_index = self.sections.items(.last_atom_index)[sect_id];
const sect_capacity = self.allocatedSize(header.pointer_to_raw_data);
if (needed_size > sect_capacity) {
const new_offset = self.findFreeSpace(needed_size, default_file_alignment);
const current_size = if (maybe_last_atom_index) |last_atom_index| blk: {
const last_atom = self.getAtom(last_atom_index);
const sym = last_atom.getSymbol(self);
break :blk (sym.value + last_atom.size) - header.virtual_address;
} else 0;
log.debug("moving {s} from 0x{x} to 0x{x}", .{
self.getSectionName(header),
header.pointer_to_raw_data,
new_offset,
});
const amt = try self.base.file.?.copyRangeAll(
header.pointer_to_raw_data,
self.base.file.?,
new_offset,
current_size,
);
if (amt != current_size) return error.InputOutput;
header.pointer_to_raw_data = new_offset;
}
const sect_vm_capacity = self.allocatedVirtualSize(header.virtual_address);
if (needed_size > sect_vm_capacity) {
self.markRelocsDirtyByAddress(header.virtual_address + header.virtual_size);
try self.growSectionVirtualMemory(sect_id, needed_size);
}
header.virtual_size = @max(header.virtual_size, needed_size);
header.size_of_raw_data = needed_size;
}
fn growSectionVirtualMemory(self: *Coff, sect_id: u32, needed_size: u32) !void {
const header = &self.sections.items(.header)[sect_id];
const increased_size = padToIdeal(needed_size);
const old_aligned_end = header.virtual_address + mem.alignForward(u32, header.virtual_size, self.page_size);
const new_aligned_end = header.virtual_address + mem.alignForward(u32, increased_size, self.page_size);
const diff = new_aligned_end - old_aligned_end;
log.debug("growing {s} in virtual memory by {x}", .{ self.getSectionName(header), diff });
// TODO: enforce order by increasing VM addresses in self.sections container.
// This is required by the loader anyhow as far as I can tell.
for (self.sections.items(.header)[sect_id + 1 ..], 0..) |*next_header, next_sect_id| {
const maybe_last_atom_index = self.sections.items(.last_atom_index)[sect_id + 1 + next_sect_id];
next_header.virtual_address += diff;
if (maybe_last_atom_index) |last_atom_index| {
var atom_index = last_atom_index;
while (true) {
const atom = self.getAtom(atom_index);
const sym = atom.getSymbolPtr(self);
sym.value += diff;
if (atom.prev_index) |prev_index| {
atom_index = prev_index;
} else break;
}
}
}
header.virtual_size = increased_size;
}
fn allocateAtom(self: *Coff, atom_index: Atom.Index, new_atom_size: u32, alignment: u32) !u32 {
const tracy = trace(@src());
defer tracy.end();
const atom = self.getAtom(atom_index);
const sect_id = @intFromEnum(atom.getSymbol(self).section_number) - 1;
const header = &self.sections.items(.header)[sect_id];
const free_list = &self.sections.items(.free_list)[sect_id];
const maybe_last_atom_index = &self.sections.items(.last_atom_index)[sect_id];
const new_atom_ideal_capacity = if (header.isCode()) padToIdeal(new_atom_size) else new_atom_size;
// We use these to indicate our intention to update metadata, placing the new atom,
// and possibly removing a free list node.
// It would be simpler to do it inside the for loop below, but that would cause a
// problem if an error was returned later in the function. So this action
// is actually carried out at the end of the function, when errors are no longer possible.
var atom_placement: ?Atom.Index = null;
var free_list_removal: ?usize = null;
// First we look for an appropriately sized free list node.
// The list is unordered. We'll just take the first thing that works.
var vaddr = blk: {
var i: usize = 0;
while (i < free_list.items.len) {
const big_atom_index = free_list.items[i];
const big_atom = self.getAtom(big_atom_index);
// We now have a pointer to a live atom that has too much capacity.
// Is it enough that we could fit this new atom?
const sym = big_atom.getSymbol(self);
const capacity = big_atom.capacity(self);
const ideal_capacity = if (header.isCode()) padToIdeal(capacity) else capacity;
const ideal_capacity_end_vaddr = math.add(u32, sym.value, ideal_capacity) catch ideal_capacity;
const capacity_end_vaddr = sym.value + capacity;
const new_start_vaddr_unaligned = capacity_end_vaddr - new_atom_ideal_capacity;
const new_start_vaddr = mem.alignBackward(u32, new_start_vaddr_unaligned, alignment);
if (new_start_vaddr < ideal_capacity_end_vaddr) {
// Additional bookkeeping here to notice if this free list node
// should be deleted because the atom that it points to has grown to take up
// more of the extra capacity.
if (!big_atom.freeListEligible(self)) {
_ = free_list.swapRemove(i);
} else {
i += 1;
}
continue;
}
// At this point we know that we will place the new atom here. But the
// remaining question is whether there is still yet enough capacity left
// over for there to still be a free list node.
const remaining_capacity = new_start_vaddr - ideal_capacity_end_vaddr;
const keep_free_list_node = remaining_capacity >= min_text_capacity;
// Set up the metadata to be updated, after errors are no longer possible.
atom_placement = big_atom_index;
if (!keep_free_list_node) {
free_list_removal = i;
}
break :blk new_start_vaddr;
} else if (maybe_last_atom_index.*) |last_index| {
const last = self.getAtom(last_index);
const last_symbol = last.getSymbol(self);
const ideal_capacity = if (header.isCode()) padToIdeal(last.size) else last.size;
const ideal_capacity_end_vaddr = last_symbol.value + ideal_capacity;
const new_start_vaddr = mem.alignForward(u32, ideal_capacity_end_vaddr, alignment);
atom_placement = last_index;
break :blk new_start_vaddr;
} else {
break :blk mem.alignForward(u32, header.virtual_address, alignment);
}
};
const expand_section = if (atom_placement) |placement_index|
self.getAtom(placement_index).next_index == null
else
true;
if (expand_section) {
const needed_size: u32 = (vaddr + new_atom_size) - header.virtual_address;
try self.growSection(sect_id, needed_size);
maybe_last_atom_index.* = atom_index;
}
self.getAtomPtr(atom_index).size = new_atom_size;
if (atom.prev_index) |prev_index| {
const prev = self.getAtomPtr(prev_index);
prev.next_index = atom.next_index;
}
if (atom.next_index) |next_index| {
const next = self.getAtomPtr(next_index);
next.prev_index = atom.prev_index;
}
if (atom_placement) |big_atom_index| {
const big_atom = self.getAtomPtr(big_atom_index);
const atom_ptr = self.getAtomPtr(atom_index);
atom_ptr.prev_index = big_atom_index;
atom_ptr.next_index = big_atom.next_index;
big_atom.next_index = atom_index;
} else {
const atom_ptr = self.getAtomPtr(atom_index);
atom_ptr.prev_index = null;
atom_ptr.next_index = null;
}
if (free_list_removal) |i| {
_ = free_list.swapRemove(i);
}
return vaddr;
}
pub fn allocateSymbol(self: *Coff) !u32 {
const gpa = self.base.allocator;
try self.locals.ensureUnusedCapacity(gpa, 1);
const index = blk: {
if (self.locals_free_list.popOrNull()) |index| {
log.debug(" (reusing symbol index {d})", .{index});
break :blk index;
} else {
log.debug(" (allocating symbol index {d})", .{self.locals.items.len});
const index = @as(u32, @intCast(self.locals.items.len));
_ = self.locals.addOneAssumeCapacity();
break :blk index;
}
};
self.locals.items[index] = .{
.name = [_]u8{0} ** 8,
.value = 0,
.section_number = .UNDEFINED,
.type = .{ .base_type = .NULL, .complex_type = .NULL },
.storage_class = .NULL,
.number_of_aux_symbols = 0,
};
return index;
}
fn allocateGlobal(self: *Coff) !u32 {
const gpa = self.base.allocator;
try self.globals.ensureUnusedCapacity(gpa, 1);
const index = blk: {
if (self.globals_free_list.popOrNull()) |index| {
log.debug(" (reusing global index {d})", .{index});
break :blk index;
} else {
log.debug(" (allocating global index {d})", .{self.globals.items.len});
const index = @as(u32, @intCast(self.globals.items.len));
_ = self.globals.addOneAssumeCapacity();
break :blk index;
}
};
self.globals.items[index] = .{
.sym_index = 0,
.file = null,
};
return index;
}
fn addGotEntry(self: *Coff, target: SymbolWithLoc) !void {
if (self.got_table.lookup.contains(target)) return;
const got_index = try self.got_table.allocateEntry(self.base.allocator, target);
try self.writeOffsetTableEntry(got_index);
self.got_table_count_dirty = true;
self.markRelocsDirtyByTarget(target);
}
pub fn createAtom(self: *Coff) !Atom.Index {
const gpa = self.base.allocator;
const atom_index = @as(Atom.Index, @intCast(self.atoms.items.len));
const atom = try self.atoms.addOne(gpa);
const sym_index = try self.allocateSymbol();
try self.atom_by_index_table.putNoClobber(gpa, sym_index, atom_index);
atom.* = .{
.sym_index = sym_index,
.file = null,
.size = 0,
.prev_index = null,
.next_index = null,
};
log.debug("creating ATOM(%{d}) at index {d}", .{ sym_index, atom_index });
return atom_index;
}
fn growAtom(self: *Coff, atom_index: Atom.Index, new_atom_size: u32, alignment: u32) !u32 {
const atom = self.getAtom(atom_index);
const sym = atom.getSymbol(self);
const align_ok = mem.alignBackward(u32, sym.value, alignment) == sym.value;
const need_realloc = !align_ok or new_atom_size > atom.capacity(self);
if (!need_realloc) return sym.value;
return self.allocateAtom(atom_index, new_atom_size, alignment);
}
fn shrinkAtom(self: *Coff, atom_index: Atom.Index, new_block_size: u32) void {
_ = self;
_ = atom_index;
_ = new_block_size;
// TODO check the new capacity, and if it crosses the size threshold into a big enough
// capacity, insert a free list node for it.
}
fn writeAtom(self: *Coff, atom_index: Atom.Index, code: []u8) !void {
const atom = self.getAtom(atom_index);
const sym = atom.getSymbol(self);
const section = self.sections.get(@intFromEnum(sym.section_number) - 1);
const file_offset = section.header.pointer_to_raw_data + sym.value - section.header.virtual_address;
log.debug("writing atom for symbol {s} at file offset 0x{x} to 0x{x}", .{
atom.getName(self),
file_offset,
file_offset + code.len,
});
const gpa = self.base.allocator;
// Gather relocs which can be resolved.
// We need to do this as we will be applying different slide values depending
// if we are running in hot-code swapping mode or not.
// TODO: how crazy would it be to try and apply the actual image base of the loaded
// process for the in-file values rather than the Windows defaults?
var relocs = std.ArrayList(*Relocation).init(gpa);
defer relocs.deinit();
if (self.relocs.getPtr(atom_index)) |rels| {
try relocs.ensureTotalCapacityPrecise(rels.items.len);
for (rels.items) |*reloc| {
if (reloc.isResolvable(self) and reloc.dirty) {
relocs.appendAssumeCapacity(reloc);
}
}
}
if (is_hot_update_compatible) {
if (self.base.child_pid) |handle| {
const slide = @intFromPtr(self.hot_state.loaded_base_address.?);
const mem_code = try gpa.dupe(u8, code);
defer gpa.free(mem_code);
self.resolveRelocs(atom_index, relocs.items, mem_code, slide);
const vaddr = sym.value + slide;
const pvaddr = @as(*anyopaque, @ptrFromInt(vaddr));
log.debug("writing to memory at address {x}", .{vaddr});
if (build_options.enable_logging) {
try debugMem(gpa, handle, pvaddr, mem_code);
}
if (section.header.flags.MEM_WRITE == 0) {
writeMemProtected(handle, pvaddr, mem_code) catch |err| {
log.warn("writing to protected memory failed with error: {s}", .{@errorName(err)});
};
} else {
writeMem(handle, pvaddr, mem_code) catch |err| {
log.warn("writing to protected memory failed with error: {s}", .{@errorName(err)});
};
}
}
}
self.resolveRelocs(atom_index, relocs.items, code, self.getImageBase());
try self.base.file.?.pwriteAll(code, file_offset);
// Now we can mark the relocs as resolved.
while (relocs.popOrNull()) |reloc| {
reloc.dirty = false;
}
}
fn debugMem(allocator: Allocator, handle: std.ChildProcess.Id, pvaddr: std.os.windows.LPVOID, code: []const u8) !void {
var buffer = try allocator.alloc(u8, code.len);
defer allocator.free(buffer);
const memread = try std.os.windows.ReadProcessMemory(handle, pvaddr, buffer);
log.debug("to write: {x}", .{std.fmt.fmtSliceHexLower(code)});
log.debug("in memory: {x}", .{std.fmt.fmtSliceHexLower(memread)});
}
fn writeMemProtected(handle: std.ChildProcess.Id, pvaddr: std.os.windows.LPVOID, code: []const u8) !void {
const old_prot = try std.os.windows.VirtualProtectEx(handle, pvaddr, code.len, std.os.windows.PAGE_EXECUTE_WRITECOPY);
try writeMem(handle, pvaddr, code);
// TODO: We can probably just set the pages writeable and leave it at that without having to restore the attributes.
// For that though, we want to track which page has already been modified.
_ = try std.os.windows.VirtualProtectEx(handle, pvaddr, code.len, old_prot);
}
fn writeMem(handle: std.ChildProcess.Id, pvaddr: std.os.windows.LPVOID, code: []const u8) !void {
const amt = try std.os.windows.WriteProcessMemory(handle, pvaddr, code);
if (amt != code.len) return error.InputOutput;
}
fn writeOffsetTableEntry(self: *Coff, index: usize) !void {
const sect_id = self.got_section_index.?;
if (self.got_table_count_dirty) {
const needed_size = @as(u32, @intCast(self.got_table.entries.items.len * self.ptr_width.size()));
try self.growSection(sect_id, needed_size);
self.got_table_count_dirty = false;
}
const header = &self.sections.items(.header)[sect_id];
const entry = self.got_table.entries.items[index];
const entry_value = self.getSymbol(entry).value;
const entry_offset = index * self.ptr_width.size();
const file_offset = header.pointer_to_raw_data + entry_offset;
const vmaddr = header.virtual_address + entry_offset;
log.debug("writing GOT entry {d}: @{x} => {x}", .{ index, vmaddr, entry_value + self.getImageBase() });
switch (self.ptr_width) {
.p32 => {
var buf: [4]u8 = undefined;
mem.writeIntLittle(u32, &buf, @as(u32, @intCast(entry_value + self.getImageBase())));
try self.base.file.?.pwriteAll(&buf, file_offset);
},
.p64 => {
var buf: [8]u8 = undefined;
mem.writeIntLittle(u64, &buf, entry_value + self.getImageBase());
try self.base.file.?.pwriteAll(&buf, file_offset);
},
}
if (is_hot_update_compatible) {
if (self.base.child_pid) |handle| {
const gpa = self.base.allocator;
const slide = @intFromPtr(self.hot_state.loaded_base_address.?);
const actual_vmaddr = vmaddr + slide;
const pvaddr = @as(*anyopaque, @ptrFromInt(actual_vmaddr));
log.debug("writing GOT entry to memory at address {x}", .{actual_vmaddr});
if (build_options.enable_logging) {
switch (self.ptr_width) {
.p32 => {
var buf: [4]u8 = undefined;
try debugMem(gpa, handle, pvaddr, &buf);
},
.p64 => {
var buf: [8]u8 = undefined;
try debugMem(gpa, handle, pvaddr, &buf);
},
}
}
switch (self.ptr_width) {
.p32 => {
var buf: [4]u8 = undefined;
mem.writeIntLittle(u32, &buf, @as(u32, @intCast(entry_value + slide)));
writeMem(handle, pvaddr, &buf) catch |err| {
log.warn("writing to protected memory failed with error: {s}", .{@errorName(err)});
};
},
.p64 => {
var buf: [8]u8 = undefined;
mem.writeIntLittle(u64, &buf, entry_value + slide);
writeMem(handle, pvaddr, &buf) catch |err| {
log.warn("writing to protected memory failed with error: {s}", .{@errorName(err)});
};
},
}
}
}
}
fn markRelocsDirtyByTarget(self: *Coff, target: SymbolWithLoc) void {
// TODO: reverse-lookup might come in handy here
for (self.relocs.values()) |*relocs| {
for (relocs.items) |*reloc| {
if (!reloc.target.eql(target)) continue;
reloc.dirty = true;
}
}
}
fn markRelocsDirtyByAddress(self: *Coff, addr: u32) void {
const got_moved = blk: {
const sect_id = self.got_section_index orelse break :blk false;
break :blk self.sections.items(.header)[sect_id].virtual_address > addr;
};
// TODO: dirty relocations targeting import table if that got moved in memory
for (self.relocs.values()) |*relocs| {
for (relocs.items) |*reloc| {
if (reloc.isGotIndirection()) {
reloc.dirty = reloc.dirty or got_moved;
} else {
const target_vaddr = reloc.getTargetAddress(self) orelse continue;
if (target_vaddr > addr) reloc.dirty = true;
}
}
}
// TODO: dirty only really affected GOT cells
for (self.got_table.entries.items) |entry| {
const target_addr = self.getSymbol(entry).value;
if (target_addr > addr) {
self.got_table_contents_dirty = true;
break;
}
}
}
fn resolveRelocs(self: *Coff, atom_index: Atom.Index, relocs: []*const Relocation, code: []u8, image_base: u64) void {
log.debug("relocating '{s}'", .{self.getAtom(atom_index).getName(self)});
for (relocs) |reloc| {
reloc.resolve(atom_index, code, image_base, self);
}
}
pub fn ptraceAttach(self: *Coff, handle: std.ChildProcess.Id) !void {
if (!is_hot_update_compatible) return;
log.debug("attaching to process with handle {*}", .{handle});
self.hot_state.loaded_base_address = std.os.windows.ProcessBaseAddress(handle) catch |err| {
log.warn("failed to get base address for the process with error: {s}", .{@errorName(err)});
return;
};
}
pub fn ptraceDetach(self: *Coff, handle: std.ChildProcess.Id) void {
if (!is_hot_update_compatible) return;
log.debug("detaching from process with handle {*}", .{handle});
self.hot_state.loaded_base_address = null;
}
fn freeAtom(self: *Coff, atom_index: Atom.Index) void {
log.debug("freeAtom {d}", .{atom_index});
const gpa = self.base.allocator;
// Remove any relocs and base relocs associated with this Atom
Atom.freeRelocations(self, atom_index);
const atom = self.getAtom(atom_index);
const sym = atom.getSymbol(self);
const sect_id = @intFromEnum(sym.section_number) - 1;
const free_list = &self.sections.items(.free_list)[sect_id];
var already_have_free_list_node = false;
{
var i: usize = 0;
// TODO turn free_list into a hash map
while (i < free_list.items.len) {
if (free_list.items[i] == atom_index) {
_ = free_list.swapRemove(i);
continue;
}
if (free_list.items[i] == atom.prev_index) {
already_have_free_list_node = true;
}
i += 1;
}
}
const maybe_last_atom_index = &self.sections.items(.last_atom_index)[sect_id];
if (maybe_last_atom_index.*) |last_atom_index| {
if (last_atom_index == atom_index) {
if (atom.prev_index) |prev_index| {
// TODO shrink the section size here
maybe_last_atom_index.* = prev_index;
} else {
maybe_last_atom_index.* = null;
}
}
}
if (atom.prev_index) |prev_index| {
const prev = self.getAtomPtr(prev_index);
prev.next_index = atom.next_index;
if (!already_have_free_list_node and prev.*.freeListEligible(self)) {
// The free list is heuristics, it doesn't have to be perfect, so we can
// ignore the OOM here.
free_list.append(gpa, prev_index) catch {};
}
} else {
self.getAtomPtr(atom_index).prev_index = null;
}
if (atom.next_index) |next_index| {
self.getAtomPtr(next_index).prev_index = atom.prev_index;
} else {
self.getAtomPtr(atom_index).next_index = null;
}
// Appending to free lists is allowed to fail because the free lists are heuristics based anyway.
const sym_index = atom.getSymbolIndex().?;
self.locals_free_list.append(gpa, sym_index) catch {};
// Try freeing GOT atom if this decl had one
self.got_table.freeEntry(gpa, .{ .sym_index = sym_index });
self.locals.items[sym_index].section_number = .UNDEFINED;
_ = self.atom_by_index_table.remove(sym_index);
log.debug(" adding local symbol index {d} to free list", .{sym_index});
self.getAtomPtr(atom_index).sym_index = 0;
}
pub fn updateFunc(self: *Coff, mod: *Module, func_index: InternPool.Index, air: Air, liveness: Liveness) !void {
if (build_options.skip_non_native and builtin.object_format != .coff) {
@panic("Attempted to compile for object format that was disabled by build configuration");
}
if (self.llvm_object) |llvm_object| {
return llvm_object.updateFunc(mod, func_index, air, liveness);
}
const tracy = trace(@src());
defer tracy.end();
const func = mod.funcInfo(func_index);
const decl_index = func.owner_decl;
const decl = mod.declPtr(decl_index);
const atom_index = try self.getOrCreateAtomForDecl(decl_index);
self.freeUnnamedConsts(decl_index);
Atom.freeRelocations(self, atom_index);
var code_buffer = std.ArrayList(u8).init(self.base.allocator);
defer code_buffer.deinit();
const res = try codegen.generateFunction(
&self.base,
decl.srcLoc(mod),
func_index,
air,
liveness,
&code_buffer,
.none,
);
var code = switch (res) {
.ok => code_buffer.items,
.fail => |em| {
decl.analysis = .codegen_failure;
try mod.failed_decls.put(mod.gpa, decl_index, em);
return;
},
};
try self.updateDeclCode(decl_index, code, .FUNCTION);
// Since we updated the vaddr and the size, each corresponding export
// symbol also needs to be updated.
return self.updateDeclExports(mod, decl_index, mod.getDeclExports(decl_index));
}
pub fn lowerUnnamedConst(self: *Coff, tv: TypedValue, decl_index: Module.Decl.Index) !u32 {
const gpa = self.base.allocator;
var code_buffer = std.ArrayList(u8).init(gpa);
defer code_buffer.deinit();
const mod = self.base.options.module.?;
const decl = mod.declPtr(decl_index);
const gop = try self.unnamed_const_atoms.getOrPut(gpa, decl_index);
if (!gop.found_existing) {
gop.value_ptr.* = .{};
}
const unnamed_consts = gop.value_ptr;
const atom_index = try self.createAtom();
const sym_name = blk: {
const decl_name = mod.intern_pool.stringToSlice(try decl.getFullyQualifiedName(mod));
const index = unnamed_consts.items.len;
break :blk try std.fmt.allocPrint(gpa, "__unnamed_{s}_{d}", .{ decl_name, index });
};
defer gpa.free(sym_name);
{
const atom = self.getAtom(atom_index);
const sym = atom.getSymbolPtr(self);
try self.setSymbolName(sym, sym_name);
sym.section_number = @as(coff.SectionNumber, @enumFromInt(self.rdata_section_index.? + 1));
}
const res = try codegen.generateSymbol(&self.base, decl.srcLoc(mod), tv, &code_buffer, .none, .{
.parent_atom_index = self.getAtom(atom_index).getSymbolIndex().?,
});
var code = switch (res) {
.ok => code_buffer.items,
.fail => |em| {
decl.analysis = .codegen_failure;
try mod.failed_decls.put(mod.gpa, decl_index, em);
log.err("{s}", .{em.msg});
return error.CodegenFail;
},
};
const required_alignment: u32 = @intCast(tv.ty.abiAlignment(mod).toByteUnits(0));
const atom = self.getAtomPtr(atom_index);
atom.size = @as(u32, @intCast(code.len));
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);
log.debug("allocated atom for {s} at 0x{x}", .{ sym_name, atom.getSymbol(self).value });
log.debug(" (required alignment 0x{x})", .{required_alignment});
try self.writeAtom(atom_index, code);
return atom.getSymbolIndex().?;
}
pub fn updateDecl(
self: *Coff,
mod: *Module,
decl_index: Module.Decl.Index,
) link.File.UpdateDeclError!void {
if (build_options.skip_non_native and builtin.object_format != .coff) {
@panic("Attempted to compile for object format that was disabled by build configuration");
}
if (self.llvm_object) |llvm_object| return llvm_object.updateDecl(mod, decl_index);
const tracy = trace(@src());
defer tracy.end();
const decl = mod.declPtr(decl_index);
if (decl.val.getExternFunc(mod)) |_| {
return; // TODO Should we do more when front-end analyzed extern decl?
}
if (decl.val.getVariable(mod)) |variable| {
if (variable.is_extern) {
return; // TODO Should we do more when front-end analyzed extern decl?
}
}
const atom_index = try self.getOrCreateAtomForDecl(decl_index);
Atom.freeRelocations(self, atom_index);
const atom = self.getAtom(atom_index);
var code_buffer = std.ArrayList(u8).init(self.base.allocator);
defer code_buffer.deinit();
const decl_val = if (decl.val.getVariable(mod)) |variable| variable.init.toValue() else decl.val;
const res = try codegen.generateSymbol(&self.base, decl.srcLoc(mod), .{
.ty = decl.ty,
.val = decl_val,
}, &code_buffer, .none, .{
.parent_atom_index = atom.getSymbolIndex().?,
});
var code = switch (res) {
.ok => code_buffer.items,
.fail => |em| {
decl.analysis = .codegen_failure;
try mod.failed_decls.put(mod.gpa, decl_index, em);
return;
},
};
try self.updateDeclCode(decl_index, code, .NULL);
// Since we updated the vaddr and the size, each corresponding export
// symbol also needs to be updated.
return self.updateDeclExports(mod, decl_index, mod.getDeclExports(decl_index));
}
fn updateLazySymbolAtom(
self: *Coff,
sym: link.File.LazySymbol,
atom_index: Atom.Index,
section_index: u16,
) !void {
const gpa = self.base.allocator;
const mod = self.base.options.module.?;
var required_alignment: InternPool.Alignment = .none;
var code_buffer = std.ArrayList(u8).init(gpa);
defer code_buffer.deinit();
const name = try std.fmt.allocPrint(gpa, "__lazy_{s}_{}", .{
@tagName(sym.kind),
sym.ty.fmt(mod),
});
defer gpa.free(name);
const atom = self.getAtomPtr(atom_index);
const local_sym_index = atom.getSymbolIndex().?;
const src = if (sym.ty.getOwnerDeclOrNull(mod)) |owner_decl|
mod.declPtr(owner_decl).srcLoc(mod)
else
Module.SrcLoc{
.file_scope = undefined,
.parent_decl_node = undefined,
.lazy = .unneeded,
};
const res = try codegen.generateLazySymbol(
&self.base,
src,
sym,
&required_alignment,
&code_buffer,
.none,
.{ .parent_atom_index = local_sym_index },
);
const code = switch (res) {
.ok => code_buffer.items,
.fail => |em| {
log.err("{s}", .{em.msg});
return error.CodegenFail;
},
};
const code_len = @as(u32, @intCast(code.len));
const symbol = atom.getSymbolPtr(self);
try self.setSymbolName(symbol, name);
symbol.section_number = @as(coff.SectionNumber, @enumFromInt(section_index + 1));
symbol.type = .{ .complex_type = .NULL, .base_type = .NULL };
const vaddr = try self.allocateAtom(atom_index, code_len, @intCast(required_alignment.toByteUnits(0)));
errdefer self.freeAtom(atom_index);
log.debug("allocated atom for {s} at 0x{x}", .{ name, vaddr });
log.debug(" (required alignment 0x{x})", .{required_alignment});
atom.size = code_len;
symbol.value = vaddr;
try self.addGotEntry(.{ .sym_index = local_sym_index });
try self.writeAtom(atom_index, code);
}
pub fn getOrCreateAtomForLazySymbol(self: *Coff, sym: link.File.LazySymbol) !Atom.Index {
const mod = self.base.options.module.?;
const gop = try self.lazy_syms.getOrPut(self.base.allocator, sym.getDecl(mod));
errdefer _ = if (!gop.found_existing) self.lazy_syms.pop();
if (!gop.found_existing) gop.value_ptr.* = .{};
const metadata: struct { atom: *Atom.Index, state: *LazySymbolMetadata.State } = switch (sym.kind) {
.code => .{ .atom = &gop.value_ptr.text_atom, .state = &gop.value_ptr.text_state },
.const_data => .{ .atom = &gop.value_ptr.rdata_atom, .state = &gop.value_ptr.rdata_state },
};
switch (metadata.state.*) {
.unused => metadata.atom.* = try self.createAtom(),
.pending_flush => return metadata.atom.*,
.flushed => {},
}
metadata.state.* = .pending_flush;
const atom = metadata.atom.*;
// anyerror needs to be deferred until flushModule
if (sym.getDecl(mod) != .none) try self.updateLazySymbolAtom(sym, atom, switch (sym.kind) {
.code => self.text_section_index.?,
.const_data => self.rdata_section_index.?,
});
return atom;
}
pub fn getOrCreateAtomForDecl(self: *Coff, decl_index: Module.Decl.Index) !Atom.Index {
const gop = try self.decls.getOrPut(self.base.allocator, decl_index);
if (!gop.found_existing) {
gop.value_ptr.* = .{
.atom = try self.createAtom(),
.section = self.getDeclOutputSection(decl_index),
.exports = .{},
};
}
return gop.value_ptr.atom;
}
fn getDeclOutputSection(self: *Coff, decl_index: Module.Decl.Index) u16 {
const decl = self.base.options.module.?.declPtr(decl_index);
const ty = decl.ty;
const mod = self.base.options.module.?;
const zig_ty = ty.zigTypeTag(mod);
const val = decl.val;
const index: u16 = blk: {
if (val.isUndefDeep(mod)) {
// TODO in release-fast and release-small, we should put undef in .bss
break :blk self.data_section_index.?;
}
switch (zig_ty) {
// TODO: what if this is a function pointer?
.Fn => break :blk self.text_section_index.?,
else => {
if (val.getVariable(mod)) |_| {
break :blk self.data_section_index.?;
}
break :blk self.rdata_section_index.?;
},
}
};
return index;
}
fn updateDeclCode(self: *Coff, decl_index: Module.Decl.Index, code: []u8, complex_type: coff.ComplexType) !void {
const mod = self.base.options.module.?;
const decl = mod.declPtr(decl_index);
const decl_name = mod.intern_pool.stringToSlice(try decl.getFullyQualifiedName(mod));
log.debug("updateDeclCode {s}{*}", .{ decl_name, decl });
const required_alignment: u32 = @intCast(decl.getAlignment(mod).toByteUnits(0));
const decl_metadata = self.decls.get(decl_index).?;
const atom_index = decl_metadata.atom;
const atom = self.getAtom(atom_index);
const sym_index = atom.getSymbolIndex().?;
const sect_index = decl_metadata.section;
const code_len = @as(u32, @intCast(code.len));
if (atom.size != 0) {
const sym = atom.getSymbolPtr(self);
try self.setSymbolName(sym, decl_name);
sym.section_number = @as(coff.SectionNumber, @enumFromInt(sect_index + 1));
sym.type = .{ .complex_type = complex_type, .base_type = .NULL };
const capacity = atom.capacity(self);
const need_realloc = code.len > capacity or !mem.isAlignedGeneric(u64, sym.value, required_alignment);
if (need_realloc) {
const vaddr = try self.growAtom(atom_index, code_len, required_alignment);
log.debug("growing {s} from 0x{x} to 0x{x}", .{ decl_name, sym.value, vaddr });
log.debug(" (required alignment 0x{x}", .{required_alignment});
if (vaddr != sym.value) {
sym.value = vaddr;
log.debug(" (updating GOT entry)", .{});
const got_entry_index = self.got_table.lookup.get(.{ .sym_index = sym_index }).?;
try self.writeOffsetTableEntry(got_entry_index);
self.markRelocsDirtyByTarget(.{ .sym_index = sym_index });
}
} else if (code_len < atom.size) {
self.shrinkAtom(atom_index, code_len);
}
self.getAtomPtr(atom_index).size = code_len;
} else {
const sym = atom.getSymbolPtr(self);
try self.setSymbolName(sym, decl_name);
sym.section_number = @as(coff.SectionNumber, @enumFromInt(sect_index + 1));
sym.type = .{ .complex_type = complex_type, .base_type = .NULL };
const vaddr = try self.allocateAtom(atom_index, code_len, required_alignment);
errdefer self.freeAtom(atom_index);
log.debug("allocated atom for {s} at 0x{x}", .{ decl_name, vaddr });
self.getAtomPtr(atom_index).size = code_len;
sym.value = vaddr;
try self.addGotEntry(.{ .sym_index = sym_index });
}
try self.writeAtom(atom_index, code);
}
fn freeUnnamedConsts(self: *Coff, decl_index: Module.Decl.Index) void {
const gpa = self.base.allocator;
const unnamed_consts = self.unnamed_const_atoms.getPtr(decl_index) orelse return;
for (unnamed_consts.items) |atom_index| {
self.freeAtom(atom_index);
}
unnamed_consts.clearAndFree(gpa);
}
pub fn freeDecl(self: *Coff, decl_index: Module.Decl.Index) void {
if (self.llvm_object) |llvm_object| return llvm_object.freeDecl(decl_index);
const mod = self.base.options.module.?;
const decl = mod.declPtr(decl_index);
log.debug("freeDecl {*}", .{decl});
if (self.decls.fetchOrderedRemove(decl_index)) |const_kv| {
var kv = const_kv;
self.freeAtom(kv.value.atom);
self.freeUnnamedConsts(decl_index);
kv.value.exports.deinit(self.base.allocator);
}
}
pub fn updateDeclExports(
self: *Coff,
mod: *Module,
decl_index: Module.Decl.Index,
exports: []const *Module.Export,
) link.File.UpdateDeclExportsError!void {
if (build_options.skip_non_native and builtin.object_format != .coff) {
@panic("Attempted to compile for object format that was disabled by build configuration");
}
const ip = &mod.intern_pool;
if (self.base.options.use_llvm) {
// Even in the case of LLVM, we need to notice certain exported symbols in order to
// detect the default subsystem.
for (exports) |exp| {
const exported_decl = mod.declPtr(exp.exported_decl);
if (exported_decl.getOwnedFunction(mod) == null) continue;
const winapi_cc = switch (self.base.options.target.cpu.arch) {
.x86 => std.builtin.CallingConvention.Stdcall,
else => std.builtin.CallingConvention.C,
};
const decl_cc = exported_decl.ty.fnCallingConvention(mod);
if (decl_cc == .C and ip.stringEqlSlice(exp.opts.name, "main") and
self.base.options.link_libc)
{
mod.stage1_flags.have_c_main = true;
} else if (decl_cc == winapi_cc and self.base.options.target.os.tag == .windows) {
if (ip.stringEqlSlice(exp.opts.name, "WinMain")) {
mod.stage1_flags.have_winmain = true;
} else if (ip.stringEqlSlice(exp.opts.name, "wWinMain")) {
mod.stage1_flags.have_wwinmain = true;
} else if (ip.stringEqlSlice(exp.opts.name, "WinMainCRTStartup")) {
mod.stage1_flags.have_winmain_crt_startup = true;
} else if (ip.stringEqlSlice(exp.opts.name, "wWinMainCRTStartup")) {
mod.stage1_flags.have_wwinmain_crt_startup = true;
} else if (ip.stringEqlSlice(exp.opts.name, "DllMainCRTStartup")) {
mod.stage1_flags.have_dllmain_crt_startup = true;
}
}
}
}
if (self.llvm_object) |llvm_object| return llvm_object.updateDeclExports(mod, decl_index, exports);
if (self.base.options.emit == null) return;
const gpa = self.base.allocator;
const decl = mod.declPtr(decl_index);
const atom_index = try self.getOrCreateAtomForDecl(decl_index);
const atom = self.getAtom(atom_index);
const decl_sym = atom.getSymbol(self);
const decl_metadata = self.decls.getPtr(decl_index).?;
for (exports) |exp| {
log.debug("adding new export '{}'", .{exp.opts.name.fmt(&mod.intern_pool)});
if (mod.intern_pool.stringToSliceUnwrap(exp.opts.section)) |section_name| {
if (!mem.eql(u8, section_name, ".text")) {
try mod.failed_exports.putNoClobber(
gpa,
exp,
try Module.ErrorMsg.create(
gpa,
decl.srcLoc(mod),
"Unimplemented: ExportOptions.section",
.{},
),
);
continue;
}
}
if (exp.opts.linkage == .LinkOnce) {
try mod.failed_exports.putNoClobber(
gpa,
exp,
try Module.ErrorMsg.create(
gpa,
decl.srcLoc(mod),
"Unimplemented: GlobalLinkage.LinkOnce",
.{},
),
);
continue;
}
const sym_index = decl_metadata.getExport(self, mod.intern_pool.stringToSlice(exp.opts.name)) orelse blk: {
const sym_index = try self.allocateSymbol();
try decl_metadata.exports.append(gpa, sym_index);
break :blk sym_index;
};
const sym_loc = SymbolWithLoc{ .sym_index = sym_index, .file = null };
const sym = self.getSymbolPtr(sym_loc);
try self.setSymbolName(sym, mod.intern_pool.stringToSlice(exp.opts.name));
sym.value = decl_sym.value;
sym.section_number = @as(coff.SectionNumber, @enumFromInt(self.text_section_index.? + 1));
sym.type = .{ .complex_type = .FUNCTION, .base_type = .NULL };
switch (exp.opts.linkage) {
.Strong => {
sym.storage_class = .EXTERNAL;
},
.Internal => @panic("TODO Internal"),
.Weak => @panic("TODO WeakExternal"),
else => unreachable,
}
try self.resolveGlobalSymbol(sym_loc);
}
}
pub fn deleteDeclExport(
self: *Coff,
decl_index: Module.Decl.Index,
name_ip: InternPool.NullTerminatedString,
) void {
if (self.llvm_object) |_| return;
const metadata = self.decls.getPtr(decl_index) orelse return;
const mod = self.base.options.module.?;
const name = mod.intern_pool.stringToSlice(name_ip);
const sym_index = metadata.getExportPtr(self, name) orelse return;
const gpa = self.base.allocator;
const sym_loc = SymbolWithLoc{ .sym_index = sym_index.*, .file = null };
const sym = self.getSymbolPtr(sym_loc);
log.debug("deleting export '{s}'", .{name});
assert(sym.storage_class == .EXTERNAL and sym.section_number != .UNDEFINED);
sym.* = .{
.name = [_]u8{0} ** 8,
.value = 0,
.section_number = .UNDEFINED,
.type = .{ .base_type = .NULL, .complex_type = .NULL },
.storage_class = .NULL,
.number_of_aux_symbols = 0,
};
self.locals_free_list.append(gpa, sym_index.*) catch {};
if (self.resolver.fetchRemove(name)) |entry| {
defer gpa.free(entry.key);
self.globals_free_list.append(gpa, entry.value) catch {};
self.globals.items[entry.value] = .{
.sym_index = 0,
.file = null,
};
}
sym_index.* = 0;
}
fn resolveGlobalSymbol(self: *Coff, current: SymbolWithLoc) !void {
const gpa = self.base.allocator;
const sym = self.getSymbol(current);
const sym_name = self.getSymbolName(current);
const gop = try self.getOrPutGlobalPtr(sym_name);
if (!gop.found_existing) {
gop.value_ptr.* = current;
if (sym.section_number == .UNDEFINED) {
try self.unresolved.putNoClobber(gpa, self.getGlobalIndex(sym_name).?, false);
}
return;
}
log.debug("TODO finish resolveGlobalSymbols implementation", .{});
if (sym.section_number == .UNDEFINED) return;
_ = self.unresolved.swapRemove(self.getGlobalIndex(sym_name).?);
gop.value_ptr.* = current;
}
pub fn flush(self: *Coff, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
if (self.base.options.emit == null) {
if (self.llvm_object) |llvm_object| {
return try llvm_object.flushModule(comp, prog_node);
}
return;
}
const use_lld = build_options.have_llvm and self.base.options.use_lld;
if (use_lld) {
return lld.linkWithLLD(self, comp, prog_node);
}
switch (self.base.options.output_mode) {
.Exe, .Obj => return self.flushModule(comp, prog_node),
.Lib => return error.TODOImplementWritingLibFiles,
}
}
pub fn flushModule(self: *Coff, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
const tracy = trace(@src());
defer tracy.end();
if (self.llvm_object) |llvm_object| {
return try llvm_object.flushModule(comp, prog_node);
}
var sub_prog_node = prog_node.start("COFF Flush", 0);
sub_prog_node.activate();
defer sub_prog_node.end();
const gpa = self.base.allocator;
const module = self.base.options.module orelse return error.LinkingWithoutZigSourceUnimplemented;
if (self.lazy_syms.getPtr(.none)) |metadata| {
// Most lazy symbols can be updated on first use, but
// anyerror needs to wait for everything to be flushed.
if (metadata.text_state != .unused) self.updateLazySymbolAtom(
link.File.LazySymbol.initDecl(.code, null, module),
metadata.text_atom,
self.text_section_index.?,
) catch |err| return switch (err) {
error.CodegenFail => error.FlushFailure,
else => |e| e,
};
if (metadata.rdata_state != .unused) self.updateLazySymbolAtom(
link.File.LazySymbol.initDecl(.const_data, null, module),
metadata.rdata_atom,
self.rdata_section_index.?,
) catch |err| return switch (err) {
error.CodegenFail => error.FlushFailure,
else => |e| e,
};
}
for (self.lazy_syms.values()) |*metadata| {
if (metadata.text_state != .unused) metadata.text_state = .flushed;
if (metadata.rdata_state != .unused) metadata.rdata_state = .flushed;
}
while (self.unresolved.popOrNull()) |entry| {
assert(entry.value); // We only expect imports generated by the incremental linker for now.
const global = self.globals.items[entry.key];
const sym = self.getSymbol(global);
const res = try self.import_tables.getOrPut(gpa, sym.value);
const itable = res.value_ptr;
if (!res.found_existing) {
itable.* = .{};
}
if (itable.lookup.contains(global)) continue;
// TODO: we could technically write the pointer placeholder for to-be-bound import here,
// but since this happens in flush, there is currently no point.
_ = try itable.addImport(gpa, global);
self.imports_count_dirty = true;
}
try self.writeImportTables();
for (self.relocs.keys(), self.relocs.values()) |atom_index, relocs| {
const needs_update = for (relocs.items) |reloc| {
if (reloc.dirty) break true;
} else false;
if (!needs_update) continue;
const atom = self.getAtom(atom_index);
const sym = atom.getSymbol(self);
const section = self.sections.get(@intFromEnum(sym.section_number) - 1).header;
const file_offset = section.pointer_to_raw_data + sym.value - section.virtual_address;
var code = std.ArrayList(u8).init(gpa);
defer code.deinit();
try code.resize(math.cast(usize, atom.size) orelse return error.Overflow);
const amt = try self.base.file.?.preadAll(code.items, file_offset);
if (amt != code.items.len) return error.InputOutput;
try self.writeAtom(atom_index, code.items);
}
// Update GOT if it got moved in memory.
if (self.got_table_contents_dirty) {
for (self.got_table.entries.items, 0..) |entry, i| {
if (!self.got_table.lookup.contains(entry)) continue;
// TODO: write all in one go rather than incrementally.
try self.writeOffsetTableEntry(i);
}
self.got_table_contents_dirty = false;
}
try self.writeBaseRelocations();
if (self.getEntryPoint()) |entry_sym_loc| {
self.entry_addr = self.getSymbol(entry_sym_loc).value;
}
if (build_options.enable_logging) {
self.logSymtab();
self.logImportTables();
}
try self.writeStrtab();
try self.writeDataDirectoriesHeaders();
try self.writeSectionHeaders();
if (self.entry_addr == null and self.base.options.output_mode == .Exe) {
log.debug("flushing. no_entry_point_found = true\n", .{});
self.error_flags.no_entry_point_found = true;
} else {
log.debug("flushing. no_entry_point_found = false\n", .{});
self.error_flags.no_entry_point_found = false;
try self.writeHeader();
}
assert(!self.imports_count_dirty);
}
pub fn getDeclVAddr(self: *Coff, decl_index: Module.Decl.Index, reloc_info: link.File.RelocInfo) !u64 {
assert(self.llvm_object == null);
const this_atom_index = try self.getOrCreateAtomForDecl(decl_index);
const sym_index = self.getAtom(this_atom_index).getSymbolIndex().?;
const atom_index = self.getAtomIndexForSymbol(.{ .sym_index = reloc_info.parent_atom_index, .file = null }).?;
const target = SymbolWithLoc{ .sym_index = sym_index, .file = null };
try Atom.addRelocation(self, atom_index, .{
.type = .direct,
.target = target,
.offset = @as(u32, @intCast(reloc_info.offset)),
.addend = reloc_info.addend,
.pcrel = false,
.length = 3,
});
try Atom.addBaseRelocation(self, atom_index, @as(u32, @intCast(reloc_info.offset)));
return 0;
}
pub fn getGlobalSymbol(self: *Coff, name: []const u8, lib_name_name: ?[]const u8) !u32 {
const gop = try self.getOrPutGlobalPtr(name);
const global_index = self.getGlobalIndex(name).?;
if (gop.found_existing) {
return global_index;
}
const sym_index = try self.allocateSymbol();
const sym_loc = SymbolWithLoc{ .sym_index = sym_index, .file = null };
gop.value_ptr.* = sym_loc;
const gpa = self.base.allocator;
const sym = self.getSymbolPtr(sym_loc);
try self.setSymbolName(sym, name);
sym.storage_class = .EXTERNAL;
if (lib_name_name) |lib_name| {
// We repurpose the 'value' of the Symbol struct to store an offset into
// temporary string table where we will store the library name hint.
sym.value = try self.temp_strtab.insert(gpa, lib_name);
}
try self.unresolved.putNoClobber(gpa, global_index, true);
return global_index;
}
pub fn updateDeclLineNumber(self: *Coff, module: *Module, decl_index: Module.Decl.Index) !void {
_ = self;
_ = module;
_ = decl_index;
log.debug("TODO implement updateDeclLineNumber", .{});
}
/// TODO: note if we need to rewrite base relocations by dirtying any of the entries in the global table
/// TODO: note that .ABSOLUTE is used as padding within each block; we could use this fact to do
/// incremental updates and writes into the table instead of doing it all at once
fn writeBaseRelocations(self: *Coff) !void {
const gpa = self.base.allocator;
var page_table = std.AutoHashMap(u32, std.ArrayList(coff.BaseRelocation)).init(gpa);
defer {
var it = page_table.valueIterator();
while (it.next()) |inner| {
inner.deinit();
}
page_table.deinit();
}
{
var it = self.base_relocs.iterator();
while (it.next()) |entry| {
const atom_index = entry.key_ptr.*;
const atom = self.getAtom(atom_index);
const sym = atom.getSymbol(self);
const offsets = entry.value_ptr.*;
for (offsets.items) |offset| {
const rva = sym.value + offset;
const page = mem.alignBackward(u32, rva, self.page_size);
const gop = try page_table.getOrPut(page);
if (!gop.found_existing) {
gop.value_ptr.* = std.ArrayList(coff.BaseRelocation).init(gpa);
}
try gop.value_ptr.append(.{
.offset = @as(u12, @intCast(rva - page)),
.type = .DIR64,
});
}
}
{
const header = &self.sections.items(.header)[self.got_section_index.?];
for (self.got_table.entries.items, 0..) |entry, index| {
if (!self.got_table.lookup.contains(entry)) continue;
const sym = self.getSymbol(entry);
if (sym.section_number == .UNDEFINED) continue;
const rva = @as(u32, @intCast(header.virtual_address + index * self.ptr_width.size()));
const page = mem.alignBackward(u32, rva, self.page_size);
const gop = try page_table.getOrPut(page);
if (!gop.found_existing) {
gop.value_ptr.* = std.ArrayList(coff.BaseRelocation).init(gpa);
}
try gop.value_ptr.append(.{
.offset = @as(u12, @intCast(rva - page)),
.type = .DIR64,
});
}
}
}
// Sort pages by address.
var pages = try std.ArrayList(u32).initCapacity(gpa, page_table.count());
defer pages.deinit();
{
var it = page_table.keyIterator();
while (it.next()) |page| {
pages.appendAssumeCapacity(page.*);
}
}
mem.sort(u32, pages.items, {}, std.sort.asc(u32));
var buffer = std.ArrayList(u8).init(gpa);
defer buffer.deinit();
for (pages.items) |page| {
const entries = page_table.getPtr(page).?;
// Pad to required 4byte alignment
if (!mem.isAlignedGeneric(
usize,
entries.items.len * @sizeOf(coff.BaseRelocation),
@sizeOf(u32),
)) {
try entries.append(.{
.offset = 0,
.type = .ABSOLUTE,
});
}
const block_size = @as(
u32,
@intCast(entries.items.len * @sizeOf(coff.BaseRelocation) + @sizeOf(coff.BaseRelocationDirectoryEntry)),
);
try buffer.ensureUnusedCapacity(block_size);
buffer.appendSliceAssumeCapacity(mem.asBytes(&coff.BaseRelocationDirectoryEntry{
.page_rva = page,
.block_size = block_size,
}));
buffer.appendSliceAssumeCapacity(mem.sliceAsBytes(entries.items));
}
const header = &self.sections.items(.header)[self.reloc_section_index.?];
const needed_size = @as(u32, @intCast(buffer.items.len));
try self.growSection(self.reloc_section_index.?, needed_size);
try self.base.file.?.pwriteAll(buffer.items, header.pointer_to_raw_data);
self.data_directories[@intFromEnum(coff.DirectoryEntry.BASERELOC)] = .{
.virtual_address = header.virtual_address,
.size = needed_size,
};
}
fn writeImportTables(self: *Coff) !void {
if (self.idata_section_index == null) return;
if (!self.imports_count_dirty) return;
const gpa = self.base.allocator;
const ext = ".dll";
const header = &self.sections.items(.header)[self.idata_section_index.?];
// Calculate needed size
var iat_size: u32 = 0;
var dir_table_size: u32 = @sizeOf(coff.ImportDirectoryEntry); // sentinel
var lookup_table_size: u32 = 0;
var names_table_size: u32 = 0;
var dll_names_size: u32 = 0;
for (self.import_tables.keys(), 0..) |off, i| {
const lib_name = self.temp_strtab.getAssumeExists(off);
const itable = self.import_tables.values()[i];
iat_size += itable.size() + 8;
dir_table_size += @sizeOf(coff.ImportDirectoryEntry);
lookup_table_size += @as(u32, @intCast(itable.entries.items.len + 1)) * @sizeOf(coff.ImportLookupEntry64.ByName);
for (itable.entries.items) |entry| {
const sym_name = self.getSymbolName(entry);
names_table_size += 2 + mem.alignForward(u32, @as(u32, @intCast(sym_name.len + 1)), 2);
}
dll_names_size += @as(u32, @intCast(lib_name.len + ext.len + 1));
}
const needed_size = iat_size + dir_table_size + lookup_table_size + names_table_size + dll_names_size;
try self.growSection(self.idata_section_index.?, needed_size);
// Do the actual writes
var buffer = std.ArrayList(u8).init(gpa);
defer buffer.deinit();
try buffer.ensureTotalCapacityPrecise(needed_size);
buffer.resize(needed_size) catch unreachable;
const dir_header_size = @sizeOf(coff.ImportDirectoryEntry);
const lookup_entry_size = @sizeOf(coff.ImportLookupEntry64.ByName);
var iat_offset: u32 = 0;
var dir_table_offset = iat_size;
var lookup_table_offset = dir_table_offset + dir_table_size;
var names_table_offset = lookup_table_offset + lookup_table_size;
var dll_names_offset = names_table_offset + names_table_size;
for (self.import_tables.keys(), 0..) |off, i| {
const lib_name = self.temp_strtab.getAssumeExists(off);
const itable = self.import_tables.values()[i];
// Lookup table header
const lookup_header = coff.ImportDirectoryEntry{
.import_lookup_table_rva = header.virtual_address + lookup_table_offset,
.time_date_stamp = 0,
.forwarder_chain = 0,
.name_rva = header.virtual_address + dll_names_offset,
.import_address_table_rva = header.virtual_address + iat_offset,
};
@memcpy(buffer.items[dir_table_offset..][0..@sizeOf(coff.ImportDirectoryEntry)], mem.asBytes(&lookup_header));
dir_table_offset += dir_header_size;
for (itable.entries.items) |entry| {
const import_name = self.getSymbolName(entry);
// IAT and lookup table entry
const lookup = coff.ImportLookupEntry64.ByName{ .name_table_rva = @as(u31, @intCast(header.virtual_address + names_table_offset)) };
@memcpy(
buffer.items[iat_offset..][0..@sizeOf(coff.ImportLookupEntry64.ByName)],
mem.asBytes(&lookup),
);
iat_offset += lookup_entry_size;
@memcpy(
buffer.items[lookup_table_offset..][0..@sizeOf(coff.ImportLookupEntry64.ByName)],
mem.asBytes(&lookup),
);
lookup_table_offset += lookup_entry_size;
// Names table entry
mem.writeIntLittle(u16, buffer.items[names_table_offset..][0..2], 0); // Hint set to 0 until we learn how to parse DLLs
names_table_offset += 2;
@memcpy(buffer.items[names_table_offset..][0..import_name.len], import_name);
names_table_offset += @as(u32, @intCast(import_name.len));
buffer.items[names_table_offset] = 0;
names_table_offset += 1;
if (!mem.isAlignedGeneric(usize, names_table_offset, @sizeOf(u16))) {
buffer.items[names_table_offset] = 0;
names_table_offset += 1;
}
}
// IAT sentinel
mem.writeIntLittle(u64, buffer.items[iat_offset..][0..lookup_entry_size], 0);
iat_offset += 8;
// Lookup table sentinel
@memcpy(
buffer.items[lookup_table_offset..][0..@sizeOf(coff.ImportLookupEntry64.ByName)],
mem.asBytes(&coff.ImportLookupEntry64.ByName{ .name_table_rva = 0 }),
);
lookup_table_offset += lookup_entry_size;
// DLL name
@memcpy(buffer.items[dll_names_offset..][0..lib_name.len], lib_name);
dll_names_offset += @as(u32, @intCast(lib_name.len));
@memcpy(buffer.items[dll_names_offset..][0..ext.len], ext);
dll_names_offset += @as(u32, @intCast(ext.len));
buffer.items[dll_names_offset] = 0;
dll_names_offset += 1;
}
// Sentinel
const lookup_header = coff.ImportDirectoryEntry{
.import_lookup_table_rva = 0,
.time_date_stamp = 0,
.forwarder_chain = 0,
.name_rva = 0,
.import_address_table_rva = 0,
};
@memcpy(
buffer.items[dir_table_offset..][0..@sizeOf(coff.ImportDirectoryEntry)],
mem.asBytes(&lookup_header),
);
dir_table_offset += dir_header_size;
assert(dll_names_offset == needed_size);
try self.base.file.?.pwriteAll(buffer.items, header.pointer_to_raw_data);
self.data_directories[@intFromEnum(coff.DirectoryEntry.IMPORT)] = .{
.virtual_address = header.virtual_address + iat_size,
.size = dir_table_size,
};
self.data_directories[@intFromEnum(coff.DirectoryEntry.IAT)] = .{
.virtual_address = header.virtual_address,
.size = iat_size,
};
self.imports_count_dirty = false;
}
fn writeStrtab(self: *Coff) !void {
if (self.strtab_offset == null) return;
const allocated_size = self.allocatedSize(self.strtab_offset.?);
const needed_size = @as(u32, @intCast(self.strtab.len()));
if (needed_size > allocated_size) {
self.strtab_offset = null;
self.strtab_offset = @as(u32, @intCast(self.findFreeSpace(needed_size, @alignOf(u32))));
}
log.debug("writing strtab from 0x{x} to 0x{x}", .{ self.strtab_offset.?, self.strtab_offset.? + needed_size });
var buffer = std.ArrayList(u8).init(self.base.allocator);
defer buffer.deinit();
try buffer.ensureTotalCapacityPrecise(needed_size);
buffer.appendSliceAssumeCapacity(self.strtab.items());
// Here, we do a trick in that we do not commit the size of the strtab to strtab buffer, instead
// we write the length of the strtab to a temporary buffer that goes to file.
mem.writeIntLittle(u32, buffer.items[0..4], @as(u32, @intCast(self.strtab.len())));
try self.base.file.?.pwriteAll(buffer.items, self.strtab_offset.?);
}
fn writeSectionHeaders(self: *Coff) !void {
const offset = self.getSectionHeadersOffset();
try self.base.file.?.pwriteAll(mem.sliceAsBytes(self.sections.items(.header)), offset);
}
fn writeDataDirectoriesHeaders(self: *Coff) !void {
const offset = self.getDataDirectoryHeadersOffset();
try self.base.file.?.pwriteAll(mem.sliceAsBytes(&self.data_directories), offset);
}
fn writeHeader(self: *Coff) !void {
const gpa = self.base.allocator;
var buffer = std.ArrayList(u8).init(gpa);
defer buffer.deinit();
const writer = buffer.writer();
try buffer.ensureTotalCapacity(self.getSizeOfHeaders());
writer.writeAll(msdos_stub) catch unreachable;
mem.writeIntLittle(u32, buffer.items[0x3c..][0..4], msdos_stub.len);
writer.writeAll("PE\x00\x00") catch unreachable;
var flags = coff.CoffHeaderFlags{
.EXECUTABLE_IMAGE = 1,
.DEBUG_STRIPPED = 1, // TODO
};
switch (self.ptr_width) {
.p32 => flags.@"32BIT_MACHINE" = 1,
.p64 => flags.LARGE_ADDRESS_AWARE = 1,
}
if (self.base.options.output_mode == .Lib and self.base.options.link_mode == .Dynamic) {
flags.DLL = 1;
}
const timestamp = std.time.timestamp();
const size_of_optional_header = @as(u16, @intCast(self.getOptionalHeaderSize() + self.getDataDirectoryHeadersSize()));
var coff_header = coff.CoffHeader{
.machine = coff.MachineType.fromTargetCpuArch(self.base.options.target.cpu.arch),
.number_of_sections = @as(u16, @intCast(self.sections.slice().len)), // TODO what if we prune a section
.time_date_stamp = @as(u32, @truncate(@as(u64, @bitCast(timestamp)))),
.pointer_to_symbol_table = self.strtab_offset orelse 0,
.number_of_symbols = 0,
.size_of_optional_header = size_of_optional_header,
.flags = flags,
};
writer.writeAll(mem.asBytes(&coff_header)) catch unreachable;
const dll_flags: coff.DllFlags = .{
.HIGH_ENTROPY_VA = 1, // TODO do we want to permit non-PIE builds at all?
.DYNAMIC_BASE = 1,
.TERMINAL_SERVER_AWARE = 1, // We are not a legacy app
.NX_COMPAT = 1, // We are compatible with Data Execution Prevention
};
const subsystem: coff.Subsystem = .WINDOWS_CUI;
const size_of_image: u32 = self.getSizeOfImage();
const size_of_headers: u32 = mem.alignForward(u32, self.getSizeOfHeaders(), default_file_alignment);
const image_base = self.getImageBase();
const base_of_code = self.sections.get(self.text_section_index.?).header.virtual_address;
const base_of_data = self.sections.get(self.data_section_index.?).header.virtual_address;
var size_of_code: u32 = 0;
var size_of_initialized_data: u32 = 0;
var size_of_uninitialized_data: u32 = 0;
for (self.sections.items(.header)) |header| {
if (header.flags.CNT_CODE == 1) {
size_of_code += header.size_of_raw_data;
}
if (header.flags.CNT_INITIALIZED_DATA == 1) {
size_of_initialized_data += header.size_of_raw_data;
}
if (header.flags.CNT_UNINITIALIZED_DATA == 1) {
size_of_uninitialized_data += header.size_of_raw_data;
}
}
switch (self.ptr_width) {
.p32 => {
var opt_header = coff.OptionalHeaderPE32{
.magic = coff.IMAGE_NT_OPTIONAL_HDR32_MAGIC,
.major_linker_version = 0,
.minor_linker_version = 0,
.size_of_code = size_of_code,
.size_of_initialized_data = size_of_initialized_data,
.size_of_uninitialized_data = size_of_uninitialized_data,
.address_of_entry_point = self.entry_addr orelse 0,
.base_of_code = base_of_code,
.base_of_data = base_of_data,
.image_base = @as(u32, @intCast(image_base)),
.section_alignment = self.page_size,
.file_alignment = default_file_alignment,
.major_operating_system_version = 6,
.minor_operating_system_version = 0,
.major_image_version = 0,
.minor_image_version = 0,
.major_subsystem_version = 6,
.minor_subsystem_version = 0,
.win32_version_value = 0,
.size_of_image = size_of_image,
.size_of_headers = size_of_headers,
.checksum = 0,
.subsystem = subsystem,
.dll_flags = dll_flags,
.size_of_stack_reserve = default_size_of_stack_reserve,
.size_of_stack_commit = default_size_of_stack_commit,
.size_of_heap_reserve = default_size_of_heap_reserve,
.size_of_heap_commit = default_size_of_heap_commit,
.loader_flags = 0,
.number_of_rva_and_sizes = @as(u32, @intCast(self.data_directories.len)),
};
writer.writeAll(mem.asBytes(&opt_header)) catch unreachable;
},
.p64 => {
var opt_header = coff.OptionalHeaderPE64{
.magic = coff.IMAGE_NT_OPTIONAL_HDR64_MAGIC,
.major_linker_version = 0,
.minor_linker_version = 0,
.size_of_code = size_of_code,
.size_of_initialized_data = size_of_initialized_data,
.size_of_uninitialized_data = size_of_uninitialized_data,
.address_of_entry_point = self.entry_addr orelse 0,
.base_of_code = base_of_code,
.image_base = image_base,
.section_alignment = self.page_size,
.file_alignment = default_file_alignment,
.major_operating_system_version = 6,
.minor_operating_system_version = 0,
.major_image_version = 0,
.minor_image_version = 0,
.major_subsystem_version = 6,
.minor_subsystem_version = 0,
.win32_version_value = 0,
.size_of_image = size_of_image,
.size_of_headers = size_of_headers,
.checksum = 0,
.subsystem = subsystem,
.dll_flags = dll_flags,
.size_of_stack_reserve = default_size_of_stack_reserve,
.size_of_stack_commit = default_size_of_stack_commit,
.size_of_heap_reserve = default_size_of_heap_reserve,
.size_of_heap_commit = default_size_of_heap_commit,
.loader_flags = 0,
.number_of_rva_and_sizes = @as(u32, @intCast(self.data_directories.len)),
};
writer.writeAll(mem.asBytes(&opt_header)) catch unreachable;
},
}
try self.base.file.?.pwriteAll(buffer.items, 0);
}
pub fn padToIdeal(actual_size: anytype) @TypeOf(actual_size) {
return actual_size +| (actual_size / ideal_factor);
}
fn detectAllocCollision(self: *Coff, start: u32, size: u32) ?u32 {
const headers_size = @max(self.getSizeOfHeaders(), self.page_size);
if (start < headers_size)
return headers_size;
const end = start + padToIdeal(size);
if (self.strtab_offset) |off| {
const tight_size = @as(u32, @intCast(self.strtab.len()));
const increased_size = padToIdeal(tight_size);
const test_end = off + increased_size;
if (end > off and start < test_end) {
return test_end;
}
}
for (self.sections.items(.header)) |header| {
const tight_size = header.size_of_raw_data;
const increased_size = padToIdeal(tight_size);
const test_end = header.pointer_to_raw_data + increased_size;
if (end > header.pointer_to_raw_data and start < test_end) {
return test_end;
}
}
return null;
}
fn allocatedSize(self: *Coff, start: u32) u32 {
if (start == 0)
return 0;
var min_pos: u32 = std.math.maxInt(u32);
if (self.strtab_offset) |off| {
if (off > start and off < min_pos) min_pos = off;
}
for (self.sections.items(.header)) |header| {
if (header.pointer_to_raw_data <= start) continue;
if (header.pointer_to_raw_data < min_pos) min_pos = header.pointer_to_raw_data;
}
return min_pos - start;
}
fn findFreeSpace(self: *Coff, object_size: u32, min_alignment: u32) u32 {
var start: u32 = 0;
while (self.detectAllocCollision(start, object_size)) |item_end| {
start = mem.alignForward(u32, item_end, min_alignment);
}
return start;
}
fn allocatedVirtualSize(self: *Coff, start: u32) u32 {
if (start == 0)
return 0;
var min_pos: u32 = std.math.maxInt(u32);
for (self.sections.items(.header)) |header| {
if (header.virtual_address <= start) continue;
if (header.virtual_address < min_pos) min_pos = header.virtual_address;
}
return min_pos - start;
}
inline fn getSizeOfHeaders(self: Coff) u32 {
const msdos_hdr_size = msdos_stub.len + 4;
return @as(u32, @intCast(msdos_hdr_size + @sizeOf(coff.CoffHeader) + self.getOptionalHeaderSize() +
self.getDataDirectoryHeadersSize() + self.getSectionHeadersSize()));
}
inline fn getOptionalHeaderSize(self: Coff) u32 {
return switch (self.ptr_width) {
.p32 => @as(u32, @intCast(@sizeOf(coff.OptionalHeaderPE32))),
.p64 => @as(u32, @intCast(@sizeOf(coff.OptionalHeaderPE64))),
};
}
inline fn getDataDirectoryHeadersSize(self: Coff) u32 {
return @as(u32, @intCast(self.data_directories.len * @sizeOf(coff.ImageDataDirectory)));
}
inline fn getSectionHeadersSize(self: Coff) u32 {
return @as(u32, @intCast(self.sections.slice().len * @sizeOf(coff.SectionHeader)));
}
inline fn getDataDirectoryHeadersOffset(self: Coff) u32 {
const msdos_hdr_size = msdos_stub.len + 4;
return @as(u32, @intCast(msdos_hdr_size + @sizeOf(coff.CoffHeader) + self.getOptionalHeaderSize()));
}
inline fn getSectionHeadersOffset(self: Coff) u32 {
return self.getDataDirectoryHeadersOffset() + self.getDataDirectoryHeadersSize();
}
inline fn getSizeOfImage(self: Coff) u32 {
var image_size: u32 = mem.alignForward(u32, self.getSizeOfHeaders(), self.page_size);
for (self.sections.items(.header)) |header| {
image_size += mem.alignForward(u32, header.virtual_size, self.page_size);
}
return image_size;
}
/// Returns symbol location corresponding to the set entrypoint (if any).
pub fn getEntryPoint(self: Coff) ?SymbolWithLoc {
const entry_name = self.base.options.entry orelse "wWinMainCRTStartup"; // TODO this is incomplete
const global_index = self.resolver.get(entry_name) orelse return null;
return self.globals.items[global_index];
}
pub fn getImageBase(self: Coff) u64 {
const image_base: u64 = self.base.options.image_base_override orelse switch (self.base.options.output_mode) {
.Exe => switch (self.base.options.target.cpu.arch) {
.aarch64 => @as(u64, 0x140000000),
.x86_64, .x86 => 0x400000,
else => unreachable, // unsupported target architecture
},
.Lib => 0x10000000,
.Obj => 0,
};
return image_base;
}
/// Returns pointer-to-symbol described by `sym_loc` descriptor.
pub fn getSymbolPtr(self: *Coff, sym_loc: SymbolWithLoc) *coff.Symbol {
assert(sym_loc.file == null); // TODO linking object files
return &self.locals.items[sym_loc.sym_index];
}
/// Returns symbol described by `sym_loc` descriptor.
pub fn getSymbol(self: *const Coff, sym_loc: SymbolWithLoc) *const coff.Symbol {
assert(sym_loc.file == null); // TODO linking object files
return &self.locals.items[sym_loc.sym_index];
}
/// Returns name of the symbol described by `sym_loc` descriptor.
pub fn getSymbolName(self: *const Coff, sym_loc: SymbolWithLoc) []const u8 {
assert(sym_loc.file == null); // TODO linking object files
const sym = self.getSymbol(sym_loc);
const offset = sym.getNameOffset() orelse return sym.getName().?;
return self.strtab.get(offset).?;
}
/// Returns pointer to the global entry for `name` if one exists.
pub fn getGlobalPtr(self: *Coff, name: []const u8) ?*SymbolWithLoc {
const global_index = self.resolver.get(name) orelse return null;
return &self.globals.items[global_index];
}
/// Returns the global entry for `name` if one exists.
pub fn getGlobal(self: *const Coff, name: []const u8) ?SymbolWithLoc {
const global_index = self.resolver.get(name) orelse return null;
return self.globals.items[global_index];
}
/// Returns the index of the global entry for `name` if one exists.
pub fn getGlobalIndex(self: *const Coff, name: []const u8) ?u32 {
return self.resolver.get(name);
}
/// Returns global entry at `index`.
pub fn getGlobalByIndex(self: *const Coff, index: u32) SymbolWithLoc {
assert(index < self.globals.items.len);
return self.globals.items[index];
}
const GetOrPutGlobalPtrResult = struct {
found_existing: bool,
value_ptr: *SymbolWithLoc,
};
/// Return pointer to the global entry for `name` if one exists.
/// Puts a new global entry for `name` if one doesn't exist, and
/// returns a pointer to it.
pub fn getOrPutGlobalPtr(self: *Coff, name: []const u8) !GetOrPutGlobalPtrResult {
if (self.getGlobalPtr(name)) |ptr| {
return GetOrPutGlobalPtrResult{ .found_existing = true, .value_ptr = ptr };
}
const gpa = self.base.allocator;
const global_index = try self.allocateGlobal();
const global_name = try gpa.dupe(u8, name);
_ = try self.resolver.put(gpa, global_name, global_index);
const ptr = &self.globals.items[global_index];
return GetOrPutGlobalPtrResult{ .found_existing = false, .value_ptr = ptr };
}
pub fn getAtom(self: *const Coff, atom_index: Atom.Index) Atom {
assert(atom_index < self.atoms.items.len);
return self.atoms.items[atom_index];
}
pub fn getAtomPtr(self: *Coff, atom_index: Atom.Index) *Atom {
assert(atom_index < self.atoms.items.len);
return &self.atoms.items[atom_index];
}
/// Returns atom if there is an atom referenced by the symbol described by `sym_loc` descriptor.
/// Returns null on failure.
pub fn getAtomIndexForSymbol(self: *const Coff, sym_loc: SymbolWithLoc) ?Atom.Index {
assert(sym_loc.file == null); // TODO linking with object files
return self.atom_by_index_table.get(sym_loc.sym_index);
}
fn setSectionName(self: *Coff, header: *coff.SectionHeader, name: []const u8) !void {
if (name.len <= 8) {
@memcpy(header.name[0..name.len], name);
@memset(header.name[name.len..], 0);
return;
}
const offset = try self.strtab.insert(self.base.allocator, name);
const name_offset = fmt.bufPrint(&header.name, "/{d}", .{offset}) catch unreachable;
@memset(header.name[name_offset.len..], 0);
}
fn getSectionName(self: *const Coff, header: *const coff.SectionHeader) []const u8 {
if (header.getName()) |name| {
return name;
}
const offset = header.getNameOffset().?;
return self.strtab.get(offset).?;
}
fn setSymbolName(self: *Coff, symbol: *coff.Symbol, name: []const u8) !void {
if (name.len <= 8) {
@memcpy(symbol.name[0..name.len], name);
@memset(symbol.name[name.len..], 0);
return;
}
const offset = try self.strtab.insert(self.base.allocator, name);
@memset(symbol.name[0..4], 0);
mem.writeIntLittle(u32, symbol.name[4..8], offset);
}
fn logSymAttributes(sym: *const coff.Symbol, buf: *[4]u8) []const u8 {
@memset(buf[0..4], '_');
switch (sym.section_number) {
.UNDEFINED => {
buf[3] = 'u';
switch (sym.storage_class) {
.EXTERNAL => buf[1] = 'e',
.WEAK_EXTERNAL => buf[1] = 'w',
.NULL => {},
else => unreachable,
}
},
.ABSOLUTE => unreachable, // handle ABSOLUTE
.DEBUG => unreachable,
else => {
buf[0] = 's';
switch (sym.storage_class) {
.EXTERNAL => buf[1] = 'e',
.WEAK_EXTERNAL => buf[1] = 'w',
.NULL => {},
else => unreachable,
}
},
}
return buf[0..];
}
fn logSymtab(self: *Coff) void {
var buf: [4]u8 = undefined;
log.debug("symtab:", .{});
log.debug(" object(null)", .{});
for (self.locals.items, 0..) |*sym, sym_id| {
const where = if (sym.section_number == .UNDEFINED) "ord" else "sect";
const def_index: u16 = switch (sym.section_number) {
.UNDEFINED => 0, // TODO
.ABSOLUTE => unreachable, // TODO
.DEBUG => unreachable, // TODO
else => @intFromEnum(sym.section_number),
};
log.debug(" %{d}: {?s} @{x} in {s}({d}), {s}", .{
sym_id,
self.getSymbolName(.{ .sym_index = @as(u32, @intCast(sym_id)), .file = null }),
sym.value,
where,
def_index,
logSymAttributes(sym, &buf),
});
}
log.debug("globals table:", .{});
for (self.globals.items) |sym_loc| {
const sym_name = self.getSymbolName(sym_loc);
log.debug(" {s} => %{d} in object({?d})", .{ sym_name, sym_loc.sym_index, sym_loc.file });
}
log.debug("GOT entries:", .{});
log.debug("{}", .{self.got_table});
}
fn logSections(self: *Coff) void {
log.debug("sections:", .{});
for (self.sections.items(.header)) |*header| {
log.debug(" {s}: VM({x}, {x}) FILE({x}, {x})", .{
self.getSectionName(header),
header.virtual_address,
header.virtual_address + header.virtual_size,
header.pointer_to_raw_data,
header.pointer_to_raw_data + header.size_of_raw_data,
});
}
}
fn logImportTables(self: *const Coff) void {
log.debug("import tables:", .{});
for (self.import_tables.keys(), 0..) |off, i| {
const itable = self.import_tables.values()[i];
log.debug("{}", .{itable.fmtDebug(.{
.coff_file = self,
.index = i,
.name_off = off,
})});
}
}
const Coff = @This();
const std = @import("std");
const build_options = @import("build_options");
const builtin = @import("builtin");
const assert = std.debug.assert;
const coff = std.coff;
const fmt = std.fmt;
const log = std.log.scoped(.link);
const math = std.math;
const mem = std.mem;
const Allocator = std.mem.Allocator;
const codegen = @import("../codegen.zig");
const link = @import("../link.zig");
const lld = @import("Coff/lld.zig");
const trace = @import("../tracy.zig").trace;
const Air = @import("../Air.zig");
pub const Atom = @import("Coff/Atom.zig");
const Compilation = @import("../Compilation.zig");
const ImportTable = @import("Coff/ImportTable.zig");
const Liveness = @import("../Liveness.zig");
const LlvmObject = @import("../codegen/llvm.zig").Object;
const Module = @import("../Module.zig");
const InternPool = @import("../InternPool.zig");
const Object = @import("Coff/Object.zig");
const Relocation = @import("Coff/Relocation.zig");
const TableSection = @import("table_section.zig").TableSection;
const StringTable = @import("strtab.zig").StringTable;
const Type = @import("../type.zig").Type;
const TypedValue = @import("../TypedValue.zig");
pub const base_tag: link.File.Tag = .coff;
const msdos_stub = @embedFile("msdos-stub.bin");