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x64: implement storing to MCValue.memory for PIE targets

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This commit is contained in:
Jakub Konka 2022-02-03 19:19:48 +01:00
parent 3832b58229
commit 4ca9a8d192
1 changed files with 20 additions and 8 deletions
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28
src/arch/x86_64/CodeGen.zig
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@ -1811,17 +1811,29 @@ fn store(self: *Self, ptr: MCValue, value: MCValue, ptr_ty: Type, value_ty: Type
}
},
.memory => |addr| {
if (self.bin_file.options.pie) {
return self.fail("TODO implement storing to memory when targeting PIE", .{});
}
// TODO: in case the address fits in an imm32 we can use [ds:imm32]
// instead of wasting an instruction copying the address to a register
value.freezeIfRegister(&self.register_manager);
defer value.unfreezeIfRegister(&self.register_manager);
const addr_reg = try self.copyToTmpRegister(ptr_ty, .{ .immediate = addr });
const addr_reg: Register = blk: {
if (self.bin_file.options.pie) {
const addr_reg = try self.register_manager.allocReg(null);
_ = try self.addInst(.{
.tag = .lea,
.ops = (Mir.Ops{
.reg1 = addr_reg.to64(),
.flags = 0b10,
}).encode(),
.data = .{ .got_entry = @truncate(u32, addr) },
});
break :blk addr_reg;
} else {
// TODO: in case the address fits in an imm32 we can use [ds:imm32]
// instead of wasting an instruction copying the address to a register
const addr_reg = try self.copyToTmpRegister(ptr_ty, .{ .immediate = addr });
break :blk addr_reg;
}
};
// to get the actual address of the value we want to modify we have to go through the GOT
// mov reg, [reg]
_ = try self.addInst(.{