Re: [PATCH] objtool: Detect assembly code falling through to INT3 padding
From: hpa
Date: Sat May 19 2018 - 03:24:37 EST
On May 18, 2018 10:51:36 AM PDT, Alexey Dobriyan <adobriyan@xxxxxxxxx> wrote:
>On Fri, May 18, 2018 at 09:18:14AM +0200, Ingo Molnar wrote:
>> The concept of built-in kernel tooling working at the machine code
>level is just
>> so powerful - we should have added our own KCC compiler 20 years ago.
>
>...for two very serious reasons
>
>* C as a language moves very slowly, last help from the comittee were
> C99 intializers which are OK, but, say, memory model was explictly
> rejected. However the project expands and becomes more complex much
> faster than C working group sets up meetings. Compiler authors help
>with extensions but ultimately can not be relied on (see "inline"
>saga).
>
> Recently everyone was celebrating new and improved min() and max()
> macros admiring creativity and knowledge of intricate language details
> (me too, don't get this wrong).
>
> Now this is how it can be done in a language which is not stupid:
>
> constexpr int min(int a, int b)
> {
> return a < b ? a : b;
> }
>
> That's literally all. And you can also do
>
> template<typename T>
> void min(T a, char b) = delete;
>
> template<typename T>
> void min(char a, T b) = delete;
>
> because "char" is char.
>
> Having control over compiler things like that can be addded more
> quickly.
>
>
>* insulating the project from the whims of compiler authors who every
> once in a while use "undefined behaviour" or other kinds of language
> lawyering to do strange things.
>
> Other serious projects do this too. Database people use O_DIRECT
> to insulate themselves from kernel people for the very same reasons.
Sounds like you are proposing switching to C++ more than anything else.
*Steps aside and grabs popcorn*
--
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