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x86_64: resolve tlv references on first use and spill to the stack

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This avoids any arbitrary memory operand possibly clobbering rax and
sometime rdi with no warning.
This commit is contained in:
Jacob Young 2023-11-12 18:10:06 -05:00
parent 3d3153c58e
commit 80b73e3e8f
2 changed files with 32 additions and 5 deletions
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34
src/arch/x86_64/CodeGen.zig
View File

@ -1107,6 +1107,7 @@ fn formatWipMir(
.cc = .Unspecified,
.src_loc = data.self.src_loc,
};
var first = true;
for ((lower.lowerMir(data.inst) catch |err| switch (err) {
error.LowerFail => {
defer {
@ -1125,7 +1126,11 @@ fn formatWipMir(
return;
},
else => |e| return e,
}).insts) |lowered_inst| try writer.print(" | {}", .{lowered_inst});
}).insts) |lowered_inst| {
if (!first) try writer.writeAll("\ndebug(wip_mir): ");
try writer.print(" | {}", .{lowered_inst});
first = false;
}
}
fn fmtWipMir(self: *Self, inst: Mir.Inst.Index) std.fmt.Formatter(formatWipMir) {
return .{ .data = .{ .self = self, .inst = inst } };
@ -15798,11 +15803,30 @@ fn resolveInst(self: *Self, ref: Air.Inst.Ref) InnerError!MCValue {
} else mcv: {
const ip_index = Air.refToInterned(ref).?;
const gop = try self.const_tracking.getOrPut(self.gpa, ip_index);
const mcv = try self.genTypedValue(.{
.ty = ty,
.val = ip_index.toValue(),
if (!gop.found_existing) gop.value_ptr.* = InstTracking.init(init: {
const const_mcv = try self.genTypedValue(.{ .ty = ty, .val = ip_index.toValue() });
switch (const_mcv) {
.lea_tlv => |tlv_sym| if (self.bin_file.cast(link.File.Elf)) |_| {
if (self.bin_file.options.pic) {
try self.spillRegisters(&.{ .rdi, .rax });
} else {
try self.spillRegisters(&.{.rax});
}
const frame_index = try self.allocFrameIndex(FrameAlloc.init(.{
.size = 8,
.alignment = .@"8",
}));
try self.genSetMem(
.{ .frame = frame_index },
0,
Type.usize,
.{ .lea_symbol = .{ .sym = tlv_sym } },
);
break :init .{ .load_frame = .{ .index = frame_index } };
} else break :init const_mcv,
else => break :init const_mcv,
}
});
if (!gop.found_existing) gop.value_ptr.* = InstTracking.init(mcv);
break :mcv gop.value_ptr.short;
};

3
src/codegen.zig
View File

@ -912,6 +912,9 @@ fn genDeclRef(
}
const sym_index = try elf_file.zigObjectPtr().?.getOrCreateMetadataForDecl(elf_file, decl_index);
const sym = elf_file.symbol(sym_index);
if (is_threadlocal) {
return GenResult.mcv(.{ .load_tlv = sym.esym_index });
}
return GenResult.mcv(.{ .load_symbol = sym.esym_index });
} else if (bin_file.cast(link.File.MachO)) |macho_file| {
if (is_extern) {