digitalmars.D.learn - How to get the body of a function/asm statement in hexadecimal
- 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
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=?UTF-8?Q?Ali_=c3=87ehreli?=
(5/8)
Jan 29 2023
... to fool myself into thinking that 0xc3 was
. Well, arguments
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.
Jan 29 2023
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
Jan 29 2023
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.
Jan 29 2023
On 1/29/23 14:19, max haughton wrote:it is not trivial to find where the *end* of a function isI 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
Jan 29 2023