• Ruby the Roobster (16/16) Jan 29 2023 I'm trying to do something like
• =?UTF-8?Q?Ali_=c3=87ehreli?= (17/19) Jan 29 2023 Since you want to see the bytes, just cast it to ubyte*. The following
• max haughton (9/25) Jan 29 2023 The function pointer can be casted to a pointer type. It is worth
• =?UTF-8?Q?Ali_=c3=87ehreli?= (5/8) Jan 29 2023 ... to fool myself into thinking that 0xc3 was . Well, arguments

Ruby the Roobster <rubytheroobster yandex.com> writes:

I'm trying to do something like

```d
void main()
{
     auto d = &c;
     *d.writeln;
}

void c()
{
}
```

In an attempt to get the hexadecimal representation of the 
machine code of a function.  Of course, function pointers cannot 
be dereferenced.  What do?

Furthermore, I would like to be able to do the same for an `asm` 
statement.

=?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:

On 1/29/23 13:45, Ruby the Roobster wrote:

 Of course, function pointers cannot be dereferenced.

Since you want to see the bytes, just cast it to ubyte*. The following 
function dumps its own bytes:

import std;

void main() {
     enum end = 0xc3;
     for (auto p = cast(ubyte*)&_Dmain; true; ++p) {
         writefln!" %02x"(*p);
         if (*p == end) {
             break;
         }
     }
}

(It can be written more elegantly as a range expression.)

 Furthermore, I would like to be able to do the same for an `asm` 

statement.

I don't know how to get the address of asm blocks.

Ali

max haughton <maxhaton gmail.com> writes:

On Sunday, 29 January 2023 at 21:45:11 UTC, Ruby the Roobster 
wrote:
 I'm trying to do something like

 ```d
 void main()
 {
     auto d = &c;
     *d.writeln;
 }

 void c()
 {
 }
 ```

 In an attempt to get the hexadecimal representation of the 
 machine code of a function.  Of course, function pointers 
 cannot be dereferenced.  What do?

 Furthermore, I would like to be able to do the same for an 
 `asm` statement.

The function pointer can be casted to a pointer type. It is worth 
saying, however, that it is not trivial to find where the *end* 
of a function is. In X86 it's not even trivial to find the end of 
an instruction!

If you'd just like the bytes for inspection, you could use a tool 
like objdump. For more complicated situations you will need to 
use a hack to tell you where the end of a function is.

=?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:

On 1/29/23 14:19, max haughton wrote:

 it is not trivial to find where the *end* of a
 function is

I suspected as much and did run ...

 objdump

... to fool myself into thinking that 0xc3 was <end>. Well, arguments 
e.g. pointer values can have 0xc3 bytes in them. So, yes, I am fooled! :)

Ali