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codegen: make LinkerLoad a common struct shared by backends

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This commit is contained in:
Jakub Konka 2022-12-01 16:32:09 +01:00
parent 00016ab6a0
commit 5bffc17c42
4 changed files with 57 additions and 160 deletions
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176
src/arch/aarch64/CodeGen.zig
View File

@ -146,11 +146,8 @@ const MCValue = union(enum) {
/// If the type is a pointer, it means the pointer address is at
/// this memory location.
memory: u64,
/// The value is in memory but requires a linker relocation fixup:
/// * got - the value is referenced indirectly via GOT entry index (the linker emits a got-type reloc)
/// * direct - the value is referenced directly via symbol index index (the linker emits a displacement reloc)
/// * import - the value is referenced indirectly via import entry index (the linker emits an import-type reloc)
linker_load: struct { type: enum { got, direct, import }, sym_index: u32 },
/// The value is in memory but requires a linker relocation fixup.
linker_load: codegen.LinkerLoad,
/// The value is one of the stack variables.
///
/// If the type is a pointer, it means the pointer address is in
@ -217,33 +214,23 @@ const DbgInfoReloc = struct {
}
fn genVarDbgInfo(reloc: DbgInfoReloc, function: Self) !void {
const name_with_null = reloc.name.ptr[0 .. reloc.name.len + 1];
const ty = switch (reloc.tag) {
.dbg_var_ptr => reloc.ty.childType(),
.dbg_var_val => reloc.ty,
const is_ptr = switch (reloc.tag) {
.dbg_var_ptr => true,
.dbg_var_val => false,
else => unreachable,
};
// const atom= function.getDbgInfoAtomPtr();
const atom = function.getDbgInfoAtomPtr();
switch (function.debug_output) {
.dwarf => |dw| {
const dbg_info = &dw.dbg_info;
try dbg_info.append(@enumToInt(link.File.Dwarf.AbbrevKind.variable));
const endian = function.target.cpu.arch.endian();
switch (reloc.mcv) {
.register => |reg| {
try dbg_info.ensureUnusedCapacity(2);
dbg_info.appendSliceAssumeCapacity(&[2]u8{ // DW.AT.location, DW.FORM.exprloc
1, // ULEB128 dwarf expression length
reg.dwarfLocOp(),
});
const loc: link.File.Dwarf.DeclState.VarArgDbgInfoLoc = switch (reloc.mcv) {
.register => |reg| .{
.register = reg.dwarfLocOp(),
},
.ptr_stack_offset,
.stack_offset,
.stack_argument_offset,
=> |offset| {
=> |offset| blk: {
const adjusted_offset = switch (reloc.mcv) {
.ptr_stack_offset,
.stack_offset,
@ -251,110 +238,31 @@ const DbgInfoReloc = struct {
.stack_argument_offset => @intCast(i32, function.saved_regs_stack_space + offset),
else => unreachable,
};
try dbg_info.ensureUnusedCapacity(7);
const fixup = dbg_info.items.len;
dbg_info.appendSliceAssumeCapacity(&[2]u8{ // DW.AT.location, DW.FORM.exprloc
1, // we will backpatch it after we encode the displacement in LEB128
Register.x29.dwarfLocOpDeref(), // frame pointer
});
leb128.writeILEB128(dbg_info.writer(), adjusted_offset) catch unreachable;
dbg_info.items[fixup] += @intCast(u8, dbg_info.items.len - fixup - 2);
},
.memory,
.linker_load,
=> {
const ptr_width = @intCast(u8, @divExact(function.target.cpu.arch.ptrBitWidth(), 8));
const is_ptr = switch (reloc.tag) {
.dbg_var_ptr => true,
.dbg_var_val => false,
else => unreachable,
};
try dbg_info.ensureUnusedCapacity(2 + ptr_width);
dbg_info.appendSliceAssumeCapacity(&[2]u8{ // DW.AT.location, DW.FORM.exprloc
1 + ptr_width + @boolToInt(is_ptr),
DW.OP.addr, // literal address
});
const offset = @intCast(u32, dbg_info.items.len);
const addr = switch (reloc.mcv) {
.memory => |addr| addr,
else => 0,
};
switch (ptr_width) {
0...4 => {
try dbg_info.writer().writeInt(u32, @intCast(u32, addr), endian);
break :blk .{
.stack = .{
.fp_register = Register.x29.dwarfLocOpDeref(),
.offset = adjusted_offset,
},
5...8 => {
try dbg_info.writer().writeInt(u64, addr, endian);
},
else => unreachable,
}
if (is_ptr) {
// We need deref the address as we point to the value via GOT entry.
try dbg_info.append(DW.OP.deref);
}
switch (reloc.mcv) {
.linker_load => |load_struct| try dw.addExprlocReloc(
load_struct.sym_index,
offset,
is_ptr,
),
else => {},
}
};
},
.immediate => |x| {
try dbg_info.ensureUnusedCapacity(2);
const fixup = dbg_info.items.len;
dbg_info.appendSliceAssumeCapacity(&[2]u8{ // DW.AT.location, DW.FORM.exprloc
1,
if (ty.isSignedInt()) DW.OP.consts else DW.OP.constu,
});
if (ty.isSignedInt()) {
try leb128.writeILEB128(dbg_info.writer(), @bitCast(i64, x));
} else {
try leb128.writeULEB128(dbg_info.writer(), x);
}
try dbg_info.append(DW.OP.stack_value);
dbg_info.items[fixup] += @intCast(u8, dbg_info.items.len - fixup - 2);
},
.undef => {
// DW.AT.location, DW.FORM.exprloc
// uleb128(exprloc_len)
// DW.OP.implicit_value uleb128(len_of_bytes) bytes
const abi_size = @intCast(u32, ty.abiSize(function.target.*));
var implicit_value_len = std.ArrayList(u8).init(function.gpa);
defer implicit_value_len.deinit();
try leb128.writeULEB128(implicit_value_len.writer(), abi_size);
const total_exprloc_len = 1 + implicit_value_len.items.len + abi_size;
try leb128.writeULEB128(dbg_info.writer(), total_exprloc_len);
try dbg_info.ensureUnusedCapacity(total_exprloc_len);
dbg_info.appendAssumeCapacity(DW.OP.implicit_value);
dbg_info.appendSliceAssumeCapacity(implicit_value_len.items);
dbg_info.appendNTimesAssumeCapacity(0xaa, abi_size);
},
.none => {
try dbg_info.ensureUnusedCapacity(3);
dbg_info.appendSliceAssumeCapacity(&[3]u8{ // DW.AT.location, DW.FORM.exprloc
2, DW.OP.lit0, DW.OP.stack_value,
});
},
else => {
try dbg_info.ensureUnusedCapacity(2);
dbg_info.appendSliceAssumeCapacity(&[2]u8{ // DW.AT.location, DW.FORM.exprloc
1, DW.OP.nop,
});
.memory => |address| .{ .memory = .{
.address = address,
.is_ptr = is_ptr,
} },
.linker_load => |linker_load| .{ .memory = .{
.address = 0,
.is_ptr = is_ptr,
.linker_load = linker_load,
} },
.immediate => |x| .{ .immediate = x },
.undef => .undef,
.none => .none,
else => blk: {
log.debug("TODO generate debug info for {}", .{reloc.mcv});
break :blk .nop;
},
}
try dbg_info.ensureUnusedCapacity(5 + name_with_null.len);
try function.addDbgInfoTypeReloc(ty); // DW.AT.type, DW.FORM.ref4
dbg_info.appendSliceAssumeCapacity(name_with_null); // DW.AT.name, DW.FORM.string
};
try dw.genVarDbgInfo(reloc.name, reloc.ty, atom, loc);
},
.plan9 => {},
.none => {},
@ -1071,28 +979,6 @@ fn ensureProcessDeathCapacity(self: *Self, additional_count: usize) !void {
try table.ensureUnusedCapacity(self.gpa, additional_count);
}
/// Adds a Type to the .debug_info at the current position. The bytes will be populated later,
/// after codegen for this symbol is done.
fn addDbgInfoTypeReloc(self: Self, ty: Type) !void {
switch (self.debug_output) {
.dwarf => |dw| {
const dbg_info = &dw.dbg_info;
const index = dbg_info.items.len;
try dbg_info.resize(index + 4); // DW.AT.type, DW.FORM.ref4
const mod = self.bin_file.options.module.?;
const fn_owner_decl = mod.declPtr(self.mod_fn.owner_decl);
const atom = switch (self.bin_file.tag) {
.elf => &fn_owner_decl.link.elf.dbg_info_atom,
.macho => &fn_owner_decl.link.macho.dbg_info_atom,
else => unreachable,
};
try dw.addTypeRelocGlobal(atom, ty, @intCast(u32, index));
},
.plan9 => {},
.none => {},
}
}
fn allocMem(
self: *Self,
abi_size: u32,

22
src/arch/x86_64/CodeGen.zig
View File

@ -128,11 +128,8 @@ pub const MCValue = union(enum) {
/// The value is in memory at a hard-coded address.
/// If the type is a pointer, it means the pointer address is at this memory location.
memory: u64,
/// The value is in memory but requires a linker relocation fixup:
/// * got - the value is referenced indirectly via GOT entry index (the linker emits a got-type reloc)
/// * direct - the value is referenced directly via symbol index index (the linker emits a displacement reloc)
/// * import - the value is referenced indirectly via import entry index (the linker emits an import-type reloc)
linker_load: struct { type: enum { got, direct, import }, sym_index: u32 },
/// The value is in memory but requires a linker relocation fixup.
linker_load: codegen.LinkerLoad,
/// The value is one of the stack variables.
/// If the type is a pointer, it means the pointer address is in the stack at this offset.
stack_offset: i32,
@ -3865,12 +3862,15 @@ fn genVarDbgInfo(
.fp_register = Register.rbp.dwarfLocOpDeref(),
.offset = -off,
} },
.memory => |address| .{
.memory = .{
.address = address,
.is_ptr = is_ptr,
},
},
.memory => |address| .{ .memory = .{
.address = address,
.is_ptr = is_ptr,
} },
.linker_load => |linker_load| .{ .memory = .{
.address = 0,
.is_ptr = is_ptr,
.linker_load = linker_load,
} },
.immediate => |x| .{ .immediate = x },
.undef => .undef,
.none => .none,

13
src/codegen.zig
View File

@ -68,6 +68,19 @@ pub const DebugInfoOutput = union(enum) {
none,
};
/// Helper struct to denote that the value is in memory but requires a linker relocation fixup:
/// * got - the value is referenced indirectly via GOT entry index (the linker emits a got-type reloc)
/// * direct - the value is referenced directly via symbol index index (the linker emits a displacement reloc)
/// * import - the value is referenced indirectly via import entry index (the linker emits an import-type reloc)
pub const LinkerLoad = struct {
type: enum {
got,
direct,
import,
},
sym_index: u32,
};
pub fn generateFunction(
bin_file: *link.File,
src_loc: Module.SrcLoc,

6
src/link/Dwarf.zig
View File

@ -16,6 +16,7 @@ const DW = std.dwarf;
const File = link.File;
const LinkBlock = File.LinkBlock;
const LinkFn = File.LinkFn;
const LinkerLoad = @import("../codegen.zig").LinkerLoad;
const Module = @import("../Module.zig");
const Value = @import("../value.zig").Value;
const Type = @import("../type.zig").Type;
@ -616,10 +617,7 @@ pub const DeclState = struct {
memory: struct {
address: u64,
is_ptr: bool,
linker_load: ?struct {
type: enum { got, direct, import },
sym_index: u32,
} = null,
linker_load: ?LinkerLoad = null,
},
immediate: u64,
undef,