qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-09-30 14:18:32 -06:00
Code Releases Activity

6g: simplify trampoline by postponing load.

Browse Source 
TEXT tramp
		MOVQ 8(SP), AX
		ADDQ $40, AX
		MOVQ AX, 8(SP)
		JMP oldfunc

	is now

	TEXT tramp
		ADDQ $40, 8(SP)
		JMP oldfunc

	and if s/40/0/, then it simplifies to

	TEXT tramp
		JMP oldfunc

	(the tramp is still needed to satisfy
	symbol references from other object files)

R=ken
OCL=28377
CL=28381
This commit is contained in:
Russ Cox 2009-05-06 17:06:06 -07:00
parent e508c55760
commit 5a67ea3883
1 changed files with 37 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

51
src/cmd/6g/obj.c
View File

@ -553,7 +553,7 @@ void
genembedtramp(Type *t, Sig *b) genembedtramp(Type *t, Sig *b)
{ {
Sym *e; Sym *e;
int c, d, o; int c, d, o, loaded;
Prog *p; Prog *p;
Type *f; Type *f;
@ -566,9 +566,6 @@ genembedtramp(Type *t, Sig *b)
fatal("genembedtramp %T.%s", t, b->name); fatal("genembedtramp %T.%s", t, b->name);
out: out:
if(d == 0)
return;
// print("genembedtramp %d\n", d); // print("genembedtramp %d\n", d);
// print(" t = %lT\n", t); // print(" t = %lT\n", t);
// print(" name = %s\n", b->name); // print(" name = %s\n", b->name);
@ -587,20 +584,24 @@ out:
p->from.scale = 7; p->from.scale = 7;
//print("1. %P\n", p); //print("1. %P\n", p);
//MOVQ 8(SP), AX loaded = 0;
p = pc;
gins(AMOVQ, N, N);
p->from.type = D_INDIR+D_SP;
p->from.offset = 8;
p->to.type = D_AX;
//print("2. %P\n", p);
o = 0; o = 0;
for(c=d-1; c>=0; c--) { for(c=d-1; c>=0; c--) {
f = dotlist[c].field; f = dotlist[c].field;
o += f->width; o += f->width;
if(!isptr[f->type->etype]) if(!isptr[f->type->etype])
continue; continue;
if(!loaded) {
loaded = 1;
//MOVQ 8(SP), AX
p = pc;
gins(AMOVQ, N, N);
p->from.type = D_INDIR+D_SP;
p->from.offset = 8;
p->to.type = D_AX;
//print("2. %P\n", p);
}
//MOVQ o(AX), AX //MOVQ o(AX), AX
p = pc; p = pc;
gins(AMOVQ, N, N); gins(AMOVQ, N, N);
@ -616,17 +617,31 @@ out:
gins(AADDQ, N, N); gins(AADDQ, N, N);
p->from.type = D_CONST; p->from.type = D_CONST;
p->from.offset = o; p->from.offset = o;
p->to.type = D_AX; if(loaded)
p->to.type = D_AX;
else {
p->to.type = D_INDIR+D_SP;
p->to.offset = 8;
}
//print("4. %P\n", p); //print("4. %P\n", p);
} }
//MOVQ AX, 8(SP) //MOVQ AX, 8(SP)
p = pc; if(loaded) {
gins(AMOVQ, N, N); p = pc;
p->from.type = D_AX; gins(AMOVQ, N, N);
p->to.type = D_INDIR+D_SP; p->from.type = D_AX;
p->to.offset = 8; p->to.type = D_INDIR+D_SP;
p->to.offset = 8;
//print("5. %P\n", p); //print("5. %P\n", p);
} else {
// TODO(rsc): obviously this is unnecessary,
// but 6l has a bug, and it can't handle
// JMP instructions too close to the top of
// a new function.
p = pc;
gins(ANOP, N, N);
}
f = dotlist[0].field; f = dotlist[0].field;
//JMP main·*Sub_test2(SB) //JMP main·*Sub_test2(SB)