| Index: src/liblink/obj8.c |
| =================================================================== |
| --- a/src/liblink/obj8.c |
| +++ b/src/liblink/obj8.c |
| @@ -261,7 +261,7 @@ |
| static void |
| addstacksplit(Link *ctxt, LSym *cursym) |
| { |
| - Prog *p, *q; |
| + Prog *p, *q, *p1, *p2; |
| int32 autoffset, deltasp; |
| int a; |
| @@ -317,13 +317,64 @@ |
| deltasp = autoffset; |
| if(cursym->text->from.scale & WRAPPER) { |
| - // g->panicwrap += autoffset + ctxt->arch->ptrsize; |
| + // if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame |
| + // |
| + // MOVL g_panic(CX), BX |
| + // TESTL BX, BX |
| + // JEQ end |
| + // LEAL (autoffset+4)(SP), DI |
| + // CMPL panic_argp(BX), DI |
| + // JNE end |
| + // MOVL SP, panic_argp(BX) |
| + // end: |
| + // NOP |
| + // |
| + // The NOP is needed to give the jumps somewhere to land. |
| + // It is a liblink NOP, not an x86 NOP: it encodes to 0 instruction bytes. |
| + |
| p = appendp(ctxt, p); |
| - p->as = AADDL; |
| - p->from.type = D_CONST; |
| - p->from.offset = autoffset + ctxt->arch->ptrsize; |
| - p->to.type = D_INDIR+D_CX; |
| - p->to.offset = 2*ctxt->arch->ptrsize; |
| + p->as = AMOVL; |
| + p->from.type = D_INDIR+D_CX; |
| + p->from.offset = 2*ctxt->arch->ptrsize; // G.panic |
| + p->to.type = D_BX; |
| + |
| + p = appendp(ctxt, p); |
| + p->as = ATESTL; |
| + p->from.type = D_BX; |
| + p->to.type = D_BX; |
| + |
| + p = appendp(ctxt, p); |
| + p->as = AJEQ; |
| + p->to.type = D_BRANCH; |
| + p1 = p; |
| + |
| + p = appendp(ctxt, p); |
| + p->as = ALEAL; |
| + p->from.type = D_INDIR+D_SP; |
| + p->from.offset = autoffset+4; |
| + p->to.type = D_DI; |
| + |
| + p = appendp(ctxt, p); |
| + p->as = ACMPL; |
| + p->from.type = D_INDIR+D_BX; |
| + p->from.offset = 0; // Panic.argp |
| + p->to.type = D_DI; |
| + |
| + p = appendp(ctxt, p); |
| + p->as = AJNE; |
| + p->to.type = D_BRANCH; |
| + p2 = p; |
| + |
| + p = appendp(ctxt, p); |
| + p->as = AMOVL; |
| + p->from.type = D_SP; |
| + p->to.type = D_INDIR+D_BX; |
| + p->to.offset = 0; // Panic.argp |
| + |
| + p = appendp(ctxt, p); |
| + p->as = ANOP; |
| + p1->pcond = p; |
| + p2->pcond = p; |
| } |
| if(ctxt->debugzerostack && autoffset && !(cursym->text->from.scale&NOSPLIT)) { |
| @@ -396,19 +447,6 @@ |
| if(autoffset != deltasp) |
| ctxt->diag("unbalanced PUSH/POP"); |
| - if(cursym->text->from.scale & WRAPPER) { |
| - p = load_g_cx(ctxt, p); |
| - p = appendp(ctxt, p); |
| - // g->panicwrap -= autoffset + ctxt->arch->ptrsize; |
| - p->as = ASUBL; |
| - p->from.type = D_CONST; |
| - p->from.offset = autoffset + ctxt->arch->ptrsize; |
| - p->to.type = D_INDIR+D_CX; |
| - p->to.offset = 2*ctxt->arch->ptrsize; |
| - p = appendp(ctxt, p); |
| - p->as = ARET; |
| - } |
| - |
| if(autoffset) { |
| p->as = AADJSP; |
| p->from.type = D_CONST; |
