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plan9 linker: write symbol table

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Also switch to iovecs because gotta go fast.
This commit is contained in:
Jacob G-W
2021-06-06 10:27:12 -04:00
committed by Andrew Kelley
parent 798162e509
commit c114474190
2 changed files with 109 additions and 41 deletions
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94
src/link/Plan9.zig
View File

@@ -32,16 +32,18 @@ hdr: aout.ExecHdr = undefined,
fn headerSize(self: Plan9) u32 {
// fat header (currently unused)
const fat: u4 = if (self.ptr_width == .p64) 8 else 0;
return aout.ExecHdr.size() + fat;
const fat: u8 = if (self.ptr_width == .p64) 8 else 0;
return @sizeOf(aout.ExecHdr) + fat;
}
pub const DeclBlock = struct {
type: enum { text, data },
// offset in the text or data sects
offset: u32,
sym_index: usize,
pub const empty = DeclBlock{
.type = .text,
.offset = 0,
.sym_index = 0,
};
};
@@ -62,7 +64,7 @@ pub fn createEmpty(gpa: *Allocator, options: link.Options) !*Plan9 {
const ptr_width: PtrWidth = switch (options.target.cpu.arch.ptrBitWidth()) {
0...32 => .p32,
33...64 => .p64,
else => return error.UnsupportedELFArchitecture,
else => return error.UnsupportedP9Architecture,
};
const self = try gpa.create(Plan9);
self.* = .{
@@ -93,13 +95,14 @@ pub fn flush(self: *Plan9, comp: *Compilation) !void {
return self.flushModule(comp);
}
pub fn flushModule(self: *Plan9, comp: *Compilation) !void {
const tracy = trace(@src());
defer tracy.end();
const module = self.base.options.module orelse return error.LinkingWithoutZigSourceUnimplemented;
// generate the header
self.hdr.magic = try aout.magicFromArch(self.base.options.target.cpu.arch);
const file = self.base.file.?;
try file.seekTo(self.headerSize());
self.text_buf.items.len = 0;
self.data_buf.items.len = 0;
self.call_relocs.items.len = 0;
// temporary buffer
var code_buffer = std.ArrayList(u8).init(self.base.allocator);
defer code_buffer.deinit();
@@ -111,10 +114,32 @@ pub fn flushModule(self: *Plan9, comp: *Compilation) !void {
decl.link.plan9 = if (is_fn) .{
.offset = @intCast(u32, self.text_buf.items.len),
.type = .text,
.sym_index = decl.link.plan9.sym_index,
} else .{
.offset = @intCast(u32, self.data_buf.items.len),
.type = .data,
.sym_index = decl.link.plan9.sym_index,
};
if (decl.link.plan9.sym_index == 0) {
try self.syms.append(self.base.allocator, .{
.value = decl.link.plan9.offset,
.type = switch (decl.link.plan9.type) {
.text => .t,
.data => .d,
},
.name = mem.span(decl.name),
});
decl.link.plan9.sym_index = self.syms.items.len - 1;
} else {
self.syms.items[decl.link.plan9.sym_index] = .{
.value = decl.link.plan9.offset,
.type = switch (decl.link.plan9.type) {
.text => .t,
.data => .d,
},
.name = mem.span(decl.name),
};
}
const res = try codegen.generateSymbol(&self.base, decl.srcLoc(), .{
.ty = decl.ty,
.val = decl.val,
@@ -136,16 +161,35 @@ pub fn flushModule(self: *Plan9, comp: *Compilation) !void {
code_buffer.items.len = 0;
}
}
try file.writeAll(self.text_buf.items);
try file.writeAll(self.data_buf.items);
try file.seekTo(0);
var sym_buf = std.ArrayList(u8).init(self.base.allocator);
defer sym_buf.deinit();
try self.writeSyms(&sym_buf);
// generate the header
self.hdr.magic = try aout.magicFromArch(self.base.options.target.cpu.arch);
self.hdr.text = @intCast(u32, self.text_buf.items.len);
self.hdr.data = @intCast(u32, self.data_buf.items.len);
self.hdr.syms = @intCast(u32, sym_buf.items.len);
self.hdr.bss = 0;
self.hdr.pcsz = 0;
self.hdr.spsz = 0;
inline for (std.meta.fields(aout.ExecHdr)) |f| {
try file.writer().writeIntBig(f.field_type, @field(self.hdr, f.name));
}
const file = self.base.file.?;
const hdr_buf = self.hdr.toU8s();
const hdr_slice: []const u8 = &hdr_buf;
// account for the fat header
const hdr_size: u8 = if (self.ptr_width == .p32) 32 else 40;
// write it all!
var vectors: [4]std.os.iovec_const = .{
.{ .iov_base = hdr_slice.ptr, .iov_len = hdr_size },
.{ .iov_base = self.text_buf.items.ptr, .iov_len = self.text_buf.items.len },
.{ .iov_base = self.data_buf.items.ptr, .iov_len = self.data_buf.items.len },
.{ .iov_base = sym_buf.items.ptr, .iov_len = sym_buf.items.len },
// TODO spsz, pcsz
};
try file.pwritevAll(&vectors, 0);
}
pub fn freeDecl(self: *Plan9, decl: *Module.Decl) void {
assert(self.decl_table.swapRemove(decl));
@@ -173,14 +217,13 @@ pub fn updateDeclExports(
self.hdr.entry = Plan9.default_base_addr + self.headerSize() + decl.link.plan9.offset;
}
if (exp.link.plan9) |i| {
const sym = &self.syms.items[i];
sym.* = .{
self.syms.items[i] = .{
.value = decl.link.plan9.offset,
.type = switch (decl.link.plan9.type) {
.text => .T,
.data => .D,
},
.name = decl.name,
.name = exp.options.name,
};
} else {
try self.syms.append(self.base.allocator, .{
@@ -189,8 +232,9 @@ pub fn updateDeclExports(
.text => .T,
.data => .D,
},
.name = decl.name,
.name = exp.options.name,
});
exp.link.plan9 = self.syms.items.len - 1;
}
}
}
@@ -226,3 +270,17 @@ pub fn addCallReloc(self: *Plan9, code: *std.ArrayList(u8), reloc: CallReloc) !v
try self.call_relocs.append(self.base.allocator, reloc);
try code.writer().writeIntBig(u64, 0xdeadbeef);
}
pub fn writeSyms(self: *Plan9, buf: *std.ArrayList(u8)) !void {
const writer = buf.writer();
for (self.syms.items) |sym| {
if (self.ptr_width == .p32) {
try writer.writeIntBig(u32, @intCast(u32, sym.value));
} else {
try writer.writeIntBig(u64, sym.value);
}
try writer.writeByte(@enumToInt(sym.type));
try writer.writeAll(std.mem.span(sym.name));
try writer.writeByte(0);
}
}

56
src/link/plan9/a.out.zig
View File

@@ -22,7 +22,7 @@
// Idomatic translation of 9front a.out.h
const std = @import("std");
// all integers are in big-endian format (needs a byteswap)
pub const ExecHdr = struct {
pub const ExecHdr = extern struct {
magic: u32,
text: u32,
data: u32,
@@ -31,8 +31,18 @@ pub const ExecHdr = struct {
entry: u32,
spsz: u32,
pcsz: u32,
pub fn size() u8 {
return 32;
comptime {
std.debug.assert(@sizeOf(@This()) == 32);
}
/// it is up to the caller to disgard the last 8 bytes if the header is not fat
pub fn toU8s(self: *@This()) [40]u8 {
var buf: [40]u8 = undefined;
var i: u8 = 0;
inline for (std.meta.fields(@This())) |f| {
std.mem.writeIntSliceBig(u32, buf[i .. i + 4], @field(self, f.name));
i += 4;
}
return buf;
}
};
@@ -42,7 +52,7 @@ pub const ExecHdr = struct {
pub const Sym32 = struct {
value: u32, // big endian in the file
type: SymType,
name: [*:0]const u8,
name: []const u8,
};
// uchar value[8];
// char type;
@@ -50,7 +60,7 @@ pub const Sym32 = struct {
pub const Sym64 = struct {
value: u64, // big endian in the file
type: SymType,
name: [*:0]const u8,
name: []const u8,
};
// The type field is one of the following characters with the
// high bit set:
@@ -85,27 +95,27 @@ pub const SymType = enum(u8) {
m = 0x80 | 'm',
};
pub const HDR_MAGIC = @import("std").meta.promoteIntLiteral(c_int, 0x00008000, .hexadecimal);
pub const HDR_MAGIC = 0x00008000;
pub inline fn _MAGIC(f: anytype, b: anytype) @TypeOf(f | ((((@as(c_int, 4) * b) + @as(c_int, 0)) * b) + @as(c_int, 7))) {
return f | ((((@as(c_int, 4) * b) + @as(c_int, 0)) * b) + @as(c_int, 7));
}
pub const A_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 8)); // 68020
pub const I_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 11)); // intel 386
pub const J_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 12)); // intel 960 (retired)
pub const K_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 13)); // sparc
pub const V_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 16)); // mips 3000 BE
pub const X_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 17)); // att dsp 3210 (retired)
pub const M_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 18)); // mips 4000 BE
pub const D_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 19)); // amd 29000 (retired)
pub const E_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 20)); // arm
pub const Q_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 21)); // powerpc
pub const N_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 22)); // mips 4000 LE
pub const L_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 23)); // dec alpha (retired)
pub const P_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 24)); // mips 3000 LE
pub const U_MAGIC = _MAGIC(@as(c_int, 0), @as(c_int, 25)); // sparc64
pub const S_MAGIC = _MAGIC(HDR_MAGIC, @as(c_int, 26)); // amd64
pub const T_MAGIC = _MAGIC(HDR_MAGIC, @as(c_int, 27)); // powerpc64
pub const R_MAGIC = _MAGIC(HDR_MAGIC, @as(c_int, 28)); // arm64
pub const A_MAGIC = _MAGIC(0, 8); // 68020
pub const I_MAGIC = _MAGIC(0, 11); // intel 386
pub const J_MAGIC = _MAGIC(0, 12); // intel 960 (retired)
pub const K_MAGIC = _MAGIC(0, 13); // sparc
pub const V_MAGIC = _MAGIC(0, 16); // mips 3000 BE
pub const X_MAGIC = _MAGIC(0, 17); // att dsp 3210 (retired)
pub const M_MAGIC = _MAGIC(0, 18); // mips 4000 BE
pub const D_MAGIC = _MAGIC(0, 19); // amd 29000 (retired)
pub const E_MAGIC = _MAGIC(0, 20); // arm
pub const Q_MAGIC = _MAGIC(0, 21); // powerpc
pub const N_MAGIC = _MAGIC(0, 22); // mips 4000 LE
pub const L_MAGIC = _MAGIC(0, 23); // dec alpha (retired)
pub const P_MAGIC = _MAGIC(0, 24); // mips 3000 LE
pub const U_MAGIC = _MAGIC(0, 25); // sparc64
pub const S_MAGIC = _MAGIC(HDR_MAGIC, 26); // amd64
pub const T_MAGIC = _MAGIC(HDR_MAGIC, 27); // powerpc64
pub const R_MAGIC = _MAGIC(HDR_MAGIC, 28); // arm64
pub fn magicFromArch(arch: std.Target.Cpu.Arch) !u32 {
return switch (arch) {