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digitalmars.D - DMD generates calls to next operation

reply "Jeroen Bollen" <jbinero gmail.com> writes:
While inspecting assembly code generated by DMD I found this
weird bit of assembly:

0000000000000000 <_Dmain>:
     0:	55                   	push   rbp
     1:	48 8b ec             	mov    rbp,rsp
     4:	48 83 ec 10          	sub    rsp,0x10
     8:	c7 45 f8 05 00 00 00 	mov    DWORD PTR [rbp-0x8],0x5
     f:	c7 45 f8 06 00 00 00 	mov    DWORD PTR [rbp-0x8],0x6
    16:	48 89 ef             	mov    rdi,rbp
    19:	e8 00 00 00 00       	call   1e <_Dmain+0x1e>
    1e:	31 c0                	xor    eax,eax
    20:	c9                   	leave
    21:	c3                   	ret
    22:	66 0f 1f 44 00 00    	nop    WORD PTR [rax+rax*1+0x0]

It seems to call/jump to the operation right after it. Why does
it do that?

Code:

void main() {
	int x = 5;
	void innerFunc() {
		import std.stdio;
		writeln(x);
	}
	x = 6;
	innerFunc();
}

Also I don't really get where it's supposed to call innerFunc. It
seems it's never mentioned inside the generated main function.
May 20 2014
next sibling parent Artur Skawina via Digitalmars-d <digitalmars-d puremagic.com> writes:
On 05/20/14 21:46, Jeroen Bollen via Digitalmars-d wrote:
 While inspecting assembly code generated by DMD I found this
 weird bit of assembly:

    19:    e8 00 00 00 00           call   1e <_Dmain+0x1e>
    1e:    31 c0                    xor    eax,eax
    20:    c9                       leave
    21:    c3                       ret
    22:    66 0f 1f 44 00 00        nop    WORD PTR [rax+rax*1+0x0]
 
 It seems to call/jump to the operation right after it. Why does
 it do that?

http://forum.dlang.org/post/mailman.427.1364814654.4724.digitalmars-d-learn puremagic.com artur
May 20 2014
prev sibling parent "Jeroen Bollen" <jbinero gmail.com> writes:
On Tuesday, 20 May 2014 at 19:55:17 UTC, Artur Skawina via
Digitalmars-d wrote:
 On 05/20/14 21:46, Jeroen Bollen via Digitalmars-d wrote:
 While inspecting assembly code generated by DMD I found this
 weird bit of assembly:

    19:    e8 00 00 00 00           call   1e <_Dmain+0x1e>
    1e:    31 c0                    xor    eax,eax
    20:    c9                       leave
    21:    c3                       ret
    22:    66 0f 1f 44 00 00        nop    WORD PTR 
 [rax+rax*1+0x0]
 
 It seems to call/jump to the operation right after it. Why does
 it do that?

http://forum.dlang.org/post/mailman.427.1364814654.4724.digitalmars-d-learn puremagic.com artur

May 20 2014