RFR: 8289046: Undefined Behaviour in x86 class Assembler [v10]
Vladimir Kozlov
kvn at openjdk.org
Fri Jul 29 17:31:45 UTC 2022
On Fri, 29 Jul 2022 09:52:38 GMT, Andrew Haley <aph at openjdk.org> wrote:
>> All instances of type Register exhibit UB in the form of wild pointer (including null pointer) dereferences. This isn't very hard to fix: we should make Registers pointers to something rather than aliases of small integers.
>>
>> Here's an example of what was happening:
>>
>> ` rax->encoding();`
>>
>> Where rax is defined as `(Register *)0`.
>>
>> This patch things so that rax is now defined as a pointer to the start of a static array of RegisterImpl.
>>
>>
>> typedef const RegisterImpl* Register;
>> extern RegisterImpl all_Registers[RegisterImpl::number_of_declared_registers + 1] ;
>> inline constexpr Register RegisterImpl::first() { return all_Registers + 1; };
>> inline constexpr Register as_Register(int encoding) { return RegisterImpl::first() + encoding; }
>> constexpr Register rax = as_register(0);
>
> Andrew Haley has updated the pull request incrementally with one additional commit since the last revision:
>
> Fix MacroAssembler::aesctr_encrypt
I submitted new our testing.
-------------
PR: https://git.openjdk.org/jdk/pull/9261
More information about the hotspot-compiler-dev
mailing list