diff options
Diffstat (limited to 'src/cmd/8l/pass.c')
| -rw-r--r-- | src/cmd/8l/pass.c | 79 |
1 files changed, 66 insertions, 13 deletions
diff --git a/src/cmd/8l/pass.c b/src/cmd/8l/pass.c index 9034fdf3a..14dd3e0dc 100644 --- a/src/cmd/8l/pass.c +++ b/src/cmd/8l/pass.c @@ -75,6 +75,7 @@ nofollow(int a) case ARET: case AIRETL: case AIRETW: + case AUNDEF: return 1; } return 0; @@ -184,20 +185,34 @@ loop: * recurse to follow one path. * continue loop on the other. */ - q = brchain(p->link); - if(q != P && q->mark) - if(a != ALOOP) { - p->as = relinv(a); - p->link = p->pcond; + if((q = brchain(p->pcond)) != P) p->pcond = q; + if((q = brchain(p->link)) != P) + p->link = q; + if(p->from.type == D_CONST) { + if(p->from.offset == 1) { + /* + * expect conditional jump to be taken. + * rewrite so that's the fall-through case. + */ + p->as = relinv(a); + q = p->link; + p->link = p->pcond; + p->pcond = q; + } + } else { + q = p->link; + if(q->mark) + if(a != ALOOP) { + p->as = relinv(a); + p->link = p->pcond; + p->pcond = q; + } } xfol(p->link, last); - q = brchain(p->pcond); - if(q->mark) { - p->pcond = q; + if(p->pcond->mark) return; - } - p = q; + p = p->pcond; goto loop; } p = p->link; @@ -315,7 +330,7 @@ patch(void) } else if(s) { if(debug['c']) Bprint(&bso, "%s calls %s\n", TNAME, s->name); - if((s->type&~SSUB) != STEXT) { + if((s->type&SMASK) != STEXT) { /* diag prints TNAME first */ diag("undefined: %s", s->name); s->type = STEXT; @@ -524,9 +539,9 @@ dostkoff(void) q = p; } - p = appendp(p); // save frame size in DX + p = appendp(p); // save frame size in DI p->as = AMOVL; - p->to.type = D_DX; + p->to.type = D_DI; p->from.type = D_CONST; // If we ask for more stack, we'll get a minimum of StackMin bytes. @@ -565,9 +580,47 @@ dostkoff(void) p->spadj = autoffset; if(q != P) q->pcond = p; + } else { + // zero-byte stack adjustment. + // Insert a fake non-zero adjustment so that stkcheck can + // recognize the end of the stack-splitting prolog. + p = appendp(p); + p->as = ANOP; + p->spadj = -PtrSize; + p = appendp(p); + p->as = ANOP; + p->spadj = PtrSize; } deltasp = autoffset; + if(debug['Z'] && autoffset && !(cursym->text->from.scale&NOSPLIT)) { + // 8l -Z means zero the stack frame on entry. + // This slows down function calls but can help avoid + // false positives in garbage collection. + p = appendp(p); + p->as = AMOVL; + p->from.type = D_SP; + p->to.type = D_DI; + + p = appendp(p); + p->as = AMOVL; + p->from.type = D_CONST; + p->from.offset = autoffset/4; + p->to.type = D_CX; + + p = appendp(p); + p->as = AMOVL; + p->from.type = D_CONST; + p->from.offset = 0; + p->to.type = D_AX; + + p = appendp(p); + p->as = AREP; + + p = appendp(p); + p->as = ASTOSL; + } + for(; p != P; p = p->link) { a = p->from.type; if(a == D_AUTO) |