diff options
Diffstat (limited to 'lisc')
| -rw-r--r-- | lisc/isel.c | 88 | ||||
| -rw-r--r-- | lisc/lisc.h | 2 | ||||
| -rw-r--r-- | lisc/slot.txt | 33 |
3 files changed, 52 insertions, 71 deletions
diff --git a/lisc/isel.c b/lisc/isel.c index 3887114..aa3c521 100644 --- a/lisc/isel.c +++ b/lisc/isel.c @@ -341,60 +341,6 @@ seljmp(Blk *b, Fn *fn) b->jmp.type = JXJc + Cne; } -int -slota(int sz, int al /* log2 */, int *sa) -{ - int j, k, s, l, a, ret; - - a = 1 << al; - l = sz; - - if (l > a) { - /* for large slots, we just - * tack them on the next max - * alignment slot available - * todo, could sophisticate - */ - l = (l + a-1) & ~(a-1); - s = sa[NAlign-1] + l; - ret = s; - for (j=0, k=1; j<NAlign; j++, k*=2) { - l = (l + k-1) & ~(k-1); - sa[j] = sa[NAlign-1] + l; - } - } else { - j = al; - s = sa[j] + a; - ret = s; - Shift: - if (j < NAlign-1 && s < sa[j+1]) - /* ........-----------... - * ^ ^ ^ - * sa[j] sa[j]+a sa[j+1] - * - * we have to skip to the - * next large whole - */ - s = sa[j+1]; - - for (k=0; k<=j; k++) - /* move all smaller holes - * that we contain with us - */ - if (sa[k] == sa[j]) - sa[k] = s; - - if (j < NAlign-1 && s > sa[j+1]) { - /* we were in a bigger hole, - * it needs to shift further - */ - s = sa[++j] + (a *= 2); - goto Shift; - } - } - return ret; -} - typedef struct AClass AClass; struct AClass { @@ -693,8 +639,8 @@ isel(Fn *fn) int64_t sz; for (n=Tmp0; n<fn->ntmp; n++) - fn->tmp[n].spill = 0; - memset(fn->svec, 0, sizeof fn->svec); + fn->tmp[n].spill = -1; + fn->stk0 = 0; /* lower arguments */ for (b=fn->start, i=b->ins; i-b->ins < b->nins; i++) @@ -735,20 +681,22 @@ isel(Fn *fn) } /* assign slots to fast allocs */ - for (b=fn->start, i=b->ins; i-b->ins < b->nins; i++) - if (OAlloc <= i->op && i->op <= OAlloc1) { - if (rtype(i->arg[0]) != RCon) - break; - sz = fn->con[i->arg[0].val].val; - if (sz < 0 || sz >= INT_MAX-3) - diag("isel: invalid alloc size"); - n = 16 / (1 << (NAlign-1)); - sz = (sz + n-1) / n; - al = i->op - OAlloc; - s = slota(sz, al, fn->svec); - fn->tmp[i->to.val].spill = s; - i->to = R; - } + b = fn->start; + assert(NAlign == 3 && "change n=4 and sz /= 4 below"); + for (al=OAlloc, n=4; al<=OAlloc1; al++, n*=2) + for (i=b->ins; i-b->ins < b->nins; i++) + if (i->op == al) { + if (rtype(i->arg[0]) != RCon) + break; + sz = fn->con[i->arg[0].val].val; + if (sz < 0 || sz >= INT_MAX-3) + diag("isel: invalid alloc size"); + sz = (sz + n-1) & -n; + sz /= 4; + fn->tmp[i->to.val].spill = fn->stk0; + fn->stk0 -= sz; + i->to = R; + } for (b=fn->start; b; b=b->link) { for (sb=(Blk*[3]){b->s1, b->s2, 0}; *sb; sb++) diff --git a/lisc/lisc.h b/lisc/lisc.h index 127aa78..dcc3652 100644 --- a/lisc/lisc.h +++ b/lisc/lisc.h @@ -249,7 +249,7 @@ struct Fn { int retty; Blk **rpo; ulong reg; - int svec[NAlign]; + int stk0, stk1; char name[NString]; }; diff --git a/lisc/slot.txt b/lisc/slot.txt new file mode 100644 index 0000000..4eec245 --- /dev/null +++ b/lisc/slot.txt @@ -0,0 +1,33 @@ +Plan for new slot computations: + +- reverse the allocation of all stack slots + so that isel slots go below spill locations +- the fast allocs must be allocated by decreasing + alignment constraints +- instead of the svec vector, we simply need two + numbers that contain the size of both the locals + and spills (stk0, stk1) +- maybe it's time to include small alignments +- use Tmp.spill == -1 to mark unallocated slots + +Layout: + + ---------- rbp = 0 [16] + | << padding 1 >> + | .. spills .. + | <- enforce align 16 + | .. align 16 .. + | .. align 8 .. + | .. align 4 .. + | << padding 0 >> + ---------- rsp = 0 [16] + + padding 0: inserted at last minute by the code + emitter to respect the ABI + padding 1: inserted at the beginning of spill + it can be 4 or 0 + +Examples: + + if the first local is aligned 4 of size 4, its slot + number will be set 0, to emit the proper offset to |