ref: ff88594df5c5df6fb8f227ab8e5df3529ba6e72f
dir: /mi/match.c/
#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>
#include <stdarg.h>
#include <ctype.h>
#include <string.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "util.h"
#include "parse.h"
#include "mi.h"
Dtree *gendtree(Node *m, Node *val, Node **lbl, size_t nlbl);
void dtreedump(FILE *fd, Dtree *dt);
static size_t ndtree;
static Dtree **dtree;
/* Path is a integer sequence that labels a subtree of a subject tree.
* For example,
* 0 is the root
* 0,0 and 0,1 are two subtrees of the root.
*
* Note: the order of the sequence is reversed with regard to the reference paper
* "When Do Match-Compilation Heuristics Matter" by Kevin Scott and Norman Ramse.
*
* Each pattern of a match clause conrresponds to a unique Path of the subject tree.
* When we have m match clauses, for a given Path, there can be at most m patterns
* associated with the Path.
*
* Given
* match v
* | (11, 12, 13)
* | (21, 22, 23)
* | (31, 32, 33)
* | _
*
* the entries 11, 21, 31 and the wildcard pattern at the bottom have the same Path 0,1
* 12, 22, 32 have the same Path 0,2
* 13, 23, 33 have the same Path 0,3
*/
typedef struct Path {
size_t len;
int *p;
} Path;
/* Slot bundles a pattern with its corresponding Path and load value.
* The compiler will generate a comparison instruction for each (pat, load) pair.
* Each match clause corresponds to a list of slots which is populated by addrec.
*/
typedef struct Slot {
Path *path;
Node *pat;
Node *load;
} Slot;
static Slot *
mkslot(Path *path, Node *pat, Node *val)
{
Slot *s;
s = zalloc(sizeof(Slot));
s->path = path;
s->pat = pat;
s->load = val;
assert(path != (void *)1);
return s;
}
/* Frontier bundles a list of slots to be matched for a specific match clause.
* The instances of Frontier should be immutable after creation.
*/
typedef struct Frontier {
int i; /* index of the match clauses from top to bottom */
Node *lbl; /* branch target when the rule is matched */
Slot **slot; /* unmatched slots (Paths) for this match clause */
size_t nslot;
Node **cap; /* the captured variables of the pattern of this match clause */
size_t ncap;
Dtree *final; /* final state, shared by all Frontiers for a specific (indxed by i) match clause */
int hasorpat; /* the frontier comes from a match arm that contains or-pattern */
struct Frontier *next;
} Frontier;
static Node *
utag(Node *n)
{
Node *tag;
tag = mkexpr(n->loc, Outag, n, NULL);
tag->expr.type = mktype(n->loc, Tyint32);
return tag;
}
static Node *
uvalue(Node *n, Type *ty)
{
Node *elt;
elt = mkexpr(n->loc, Oudata, n, NULL);
elt->expr.type = ty;
return elt;
}
static Node *
tupelt(Node *n, size_t i)
{
Node *idx, *elt;
idx = mkintlit(n->loc, i);
idx->expr.type = mktype(n->loc, Tyuint64);
elt = mkexpr(n->loc, Otupget, n, idx, NULL);
elt->expr.type = tybase(exprtype(n))->sub[i];
return elt;
}
static Node *
arrayelt(Node *n, size_t i)
{
Node *idx, *elt;
idx = mkintlit(n->loc, i);
idx->expr.type = mktype(n->loc, Tyuint64);
elt = mkexpr(n->loc, Oidx, n, idx, NULL);
elt->expr.type = tybase(exprtype(n))->sub[0];
return elt;
}
static Node *
findmemb(Node *pat, Node *name)
{
Node *n;
size_t i;
for (i = 0; i < pat->expr.nargs; i++) {
n = pat->expr.args[i];
if (nameeq(n->expr.idx, name))
return n;
}
return NULL;
}
static Node *
structmemb(Node *n, Node *name, Type *ty)
{
Node *elt;
elt = mkexpr(n->loc, Omemb, n, name, NULL);
elt->expr.type = ty;
return elt;
}
static Node *
addcapture(Node *n, Node **cap, size_t ncap)
{
size_t i, j;
for (i = 0; i < n->block.nstmts; i++) {
if (n->block.stmts[i]->type != Ndecl)
continue;
for (j = 0; j < ncap; j++) {
assert(cap[j]->expr.op == Oasn);
assert(cap[j]->expr.args[0]->expr.op == Ovar);
assert(cap[j]->expr.args[0]->expr.isconst == 0);
if (n->block.stmts[i]->decl.did != cap[j]->expr.args[0]->expr.did)
continue;
assert(n->block.stmts[i]->decl.init == NULL);
assert(cap[j]->expr.args[0]->expr.op == Ovar);
n->block.stmts[i]->decl.init = cap[j]->expr.args[1];
}
}
return n;
}
static Dtree *
mkdtree(Srcloc loc, Node *lbl)
{
Dtree *t;
t = zalloc(sizeof(Dtree));
t->lbl = lbl;
t->loc = loc;
t->id = ndtree;
lappend(&dtree, &ndtree, t);
return t;
}
static int
loadeq(Node *a, Node *b)
{
if (a == b)
return 1;
if (exprop(a) != exprop(b))
return 0;
switch (exprop(a)) {
case Outag:
case Oudata:
case Oderef:
return loadeq(a->expr.args[0], b->expr.args[0]);
case Omemb:
return loadeq(a->expr.args[0], b->expr.args[0]) && nameeq(a->expr.args[1], b->expr.args[1]);
case Otupget:
case Oidx:
return loadeq(a->expr.args[0], b->expr.args[0]) && liteq(a->expr.args[1]->expr.args[0], b->expr.args[1]->expr.args[0]);
case Ovar:
return a == b;
default:
die("unreachable");
}
return 0;
}
static int
pateq(Node *a, Node *b)
{
if (exprop(a) != exprop(b))
return 0;
switch (exprop(a)) {
case Olit:
return liteq(a->expr.args[0], b->expr.args[0]);
case Ogap:
case Ovar:
return 1;
default:
die("unreachable");
}
return 0;
}
static int
dtreusable(Dtree *dt, Node *load, Node **pat, size_t npat, Dtree **next, size_t nnext, Dtree *any)
{
size_t i;
if (!loadeq(dt->load, load))
return 0;
if (dt->npat != npat)
return 0;
for (i = 0; i < npat; i++) {
if (dt->next[i]->id != next[i]->id)
return 0;
if (!pateq(dt->pat[i], pat[i]))
return 0;
}
if (dt->any == NULL && any == NULL)
return 1;
if (dt->any->id != any->id)
return 0;
return 1;
}
void
dtreedumplit(FILE *fd, Dtree *dt, Node *n, size_t depth)
{
char *s;
s = lblstr(dt->lbl);
switch (n->lit.littype) {
case Lvoid: findentf(fd, depth, "%s: Lvoid\n"); break;
case Lchr: findentf(fd, depth, "%s: Lchr %c\n", s, n->lit.chrval); break;
case Lbool: findentf(fd, depth, "%s: Lbool %s\n", s, n->lit.boolval ? "true" : "false"); break;
case Lint: findentf(fd, depth, "%s: Lint %llu\n", s, n->lit.intval); break;
case Lflt: findentf(fd, depth, "%s: Lflt %lf\n", s, n->lit.fltval); break;
case Lstr: findentf(fd, depth, "%s: Lstr %.*s\n", s, (int)n->lit.strval.len, n->lit.strval.buf); break;
case Llbl: findentf(fd, depth, "%s: Llbl %s\n", s, n->lit.lblval); break;
case Lfunc: findentf(fd, depth, "%s: Lfunc\n"); break;
}
}
void
dtreedumpnode(FILE *fd, Dtree *dt, size_t depth)
{
size_t i;
if (dt->accept)
findentf(fd, depth, "%s: accept\n", lblstr(dt->lbl));
for (i = 0; i < dt->nnext; i++) {
dtreedumplit(fd, dt, dt->pat[i]->expr.args[0], depth);
dtreedumpnode(fd, dt->next[i], depth + 1);
}
if (dt->any) {
findentf(fd, depth, "%s: wildcard\n", lblstr(dt->lbl));
dtreedumpnode(fd, dt->any, depth + 1);
}
}
void
dtreedump(FILE *fd, Dtree *dt)
{
dtreedumpnode(fd, dt, 0);
}
static Path*
mkpath(Path *p, int i)
{
Path *newp;
newp = zalloc(sizeof(Path));
if (p) {
newp->p = zalloc(sizeof(newp->p[0])*(p->len+1));
memcpy(newp->p, p->p, sizeof(newp->p[0])*p->len);
newp->p[p->len] = i;
newp->len = p->len+1;
} else {
newp->p = zalloc(sizeof(int)*4);
newp->p[0] = 0;
newp->len = 1;
}
assert(newp->p != 0);
return newp;
}
static int
patheq(Path *a, Path *b)
{
size_t i;
if (a->len != b->len)
return 0;
for (i = 0; i < a->len; i++) {
if (a->p[i] != b->p[i])
return 0;
}
return 1;
}
char *
pathfmt(Path *p)
{
size_t i, sz, n;
char *buf;
sz = p->len*3+1;
buf = zalloc(sz);
n = 0;
for (i = 0; i < p->len; i++) {
n += snprintf(&buf[n], sz-n, "%02x,", p->p[i]);
}
buf[n-1] = '\0';
return buf;
}
void
pathdump(Path *p, FILE *out)
{
size_t i;
for (i = 0; i < p->len; i++) {
fprintf(out, "%x,", p->p[i]);
}
fprintf(out, "\n");
}
static size_t
nconstructors(Type *t)
{
if (!t)
return 0;
t = tybase(t);
switch (t->type) {
case Tyvoid: return 1;
case Tybool: return 2;
case Tychar: return 0x10ffff;
/* signed ints */
case Tyint8: return 0x100;
case Tyint16: return 0x10000;
case Tyint32: return 0x100000000;
case Tyint: return 0x100000000;
case Tyint64: return ~0ull;
/* unsigned ints */
case Tybyte: return 0x100;
case Tyuint8: return 0x100;
case Tyuint16: return 0x10000;
case Tyuint32: return 0x100000000;
case Tyuint: return 0x100000000;
case Tyuint64: return ~0ull;
/* floats */
case Tyflt32: return ~0ull;
case Tyflt64: return ~0ull;
/* complex types */
case Typtr: return 1;
case Tyarray: return 1;
case Tytuple: return 1;
case Tystruct: return 1;
case Tyunion: return t->nmemb;
case Tyslice: return ~0ULL;
case Tyvar: case Typaram: case Tyunres: case Tyname:
case Tybad: case Tyvalist: case Tygeneric: case Ntypes:
case Tyfunc: case Tycode:
die("Invalid constructor type %s in match", tystr(t));
break;
}
return 0;
}
static Frontier *
mkfrontier(int i, Node *lbl)
{
Frontier *fs;
fs = zalloc(sizeof(Frontier));
fs->i = i;
fs->lbl = lbl;
fs->final = mkdtree(lbl->loc, lbl);
fs->final->accept = 1;
return fs;;
}
/*
* All immutable fields are shared; mutable fields must be cloned *
*/
static Frontier *
frontierdup(Frontier *fs)
{
Frontier *out;
out = mkfrontier(fs->i, fs->lbl);
out->slot = memdup(fs->slot, fs->nslot*sizeof(fs->slot[0]));
out->nslot = fs->nslot;
out->cap = memdup(fs->cap, fs->ncap*sizeof(fs->cap[0]));
out->ncap = fs->ncap;
return out;
}
/* addrec generates a list of slots for a Frontier by walking a pattern tree.
* It collects only the terminal patterns like union tags and literals.
* Non-terminal patterns like tuple/struct/array help encode the path only.
*/
static void
addrec(Frontier *fs, Node *pat, Node *val, Path *path)
{
size_t i, n;
Type *ty, *mty;
Node *memb, *name, *tagid, *p, *v, *lit, *dcl, *asn, *deref;
Ucon *uc;
char *s;
Frontier *next;
pat = fold(pat, 1);
switch (exprop(pat)) {
case Olor:
next = frontierdup(fs);
next->next = fs->next;
next->hasorpat = 1;
fs->next = next;
fs->hasorpat = 1;
addrec(fs, pat->expr.args[0], val, path);
addrec(next, pat->expr.args[1], val, path);
break;
case Ogap:
lappend(&fs->slot, &fs->nslot, mkslot(path, pat, val));
break;
case Ovar:
dcl = decls[pat->expr.did];
if (dcl->decl.isconst) {
ty = decltype(dcl);
if (ty->type == Tyfunc || ty->type == Tycode || ty->type == Tyvalist)
fatal(dcl, "bad pattern %s:%s: unmatchable type", declname(dcl), tystr(ty));
if (!dcl->decl.init)
fatal(dcl, "bad pattern %s:%s: missing initializer", declname(dcl), tystr(ty));
addrec(fs, dcl->decl.init, val, mkpath(path, 0));
} else {
asn = mkexpr(pat->loc, Oasn, pat, val, NULL);
asn->expr.type = exprtype(pat);
lappend(&fs->cap, &fs->ncap, asn);
lappend(&fs->slot, &fs->nslot, mkslot(path, pat, val));
}
break;
case Olit:
if (pat->expr.args[0]->lit.littype == Lstr) {
lit = pat->expr.args[0];
n = lit->lit.strval.len;
s = lit->lit.strval.buf;
ty = mktype(pat->loc, Tyuint64);
p = mkintlit(lit->loc, n);
p ->expr.type = ty;
v = structmemb(val, mkname(pat->loc, "len"), ty);
addrec(fs, p, v, mkpath(path, 0));
ty = mktype(pat->loc, Tybyte);
for (i = 0; i < n; i++) {
p = mkintlit(lit->loc, s[i]);
p->expr.type = ty;
v = arrayelt(val, i);
addrec(fs, p, v, mkpath(path, 1+i));
}
} else {
lappend(&fs->slot, &fs->nslot, mkslot(path, pat, val));
}
break;
case Oaddr:
deref = mkexpr(val->loc, Oderef, val, NULL);
deref->expr.type = exprtype(pat->expr.args[0]);
addrec(fs, pat->expr.args[0], deref, mkpath(path, 0));
break;
case Oucon:
uc = finducon(tybase(exprtype(pat)), pat->expr.args[0]);
tagid = mkintlit(pat->loc, uc->id);
tagid->expr.type = mktype(pat->loc, Tyint32);
addrec(fs, tagid, utag(val), mkpath(path, 0));
if (uc->etype)
addrec(fs, pat->expr.args[1], uvalue(val, uc->etype), mkpath(path, 1));
break;
case Otup:
for (i = 0; i < pat->expr.nargs; i++) {
addrec(fs, pat->expr.args[i], tupelt(val, i), mkpath(path, i));
}
break;
case Oarr:
for (i = 0; i < pat->expr.nargs; i++) {
addrec(fs, pat->expr.args[i], arrayelt(val, i), mkpath(path, i));
}
break;
case Ostruct:
ty = tybase(exprtype(pat));
for (i = 0; i < ty->nmemb; i++) {
mty = decltype(ty->sdecls[i]);
name = ty->sdecls[i]->decl.name;
memb = findmemb(pat, name);
if (!memb) {
memb = mkexpr(ty->sdecls[i]->loc, Ogap, NULL);
memb->expr.type = mty;
}
addrec(fs, memb, structmemb(val, name, mty), mkpath(path, i));
}
break;
default:
fatal(pat, "unsupported pattern %s of type %s", opstr[exprop(pat)], tystr(exprtype(pat)));
break;
}
}
static void
genfrontier(int i, Node *val, Node *pat, Node *lbl, Frontier ***frontier, size_t *nfrontier)
{
Frontier *fs;
fs = mkfrontier(i, lbl);
addrec(fs, pat, val, mkpath(NULL, 0));
while (fs != NULL) {
lappend(frontier, nfrontier, fs);
fs = fs->next;
}
}
/*
* project generates a new frontier with a new the set of slots by reducing the input slots.
* literally, it deletes the slot at the path pi.
*/
static Frontier *
project(Node *pat, Path *pi, Node *val, Frontier *fs)
{
Frontier *out;
Slot *c, **slot;
size_t i, nslot;
assert (fs->nslot > 0);
/*
* copy a new set of slots from fs without the slot at the path pi.
* c points to the slot at the path pi.
*/
c = NULL;
slot = NULL;
nslot = 0;
for (i = 0; i < fs->nslot; i++) {
if (patheq(pi, fs->slot[i]->path)) {
c = fs->slot[i];
continue;
}
lappend(&slot, &nslot, fs->slot[i]);
}
out = zalloc(sizeof(Frontier));
out->i = fs->i;
out->lbl = fs->lbl;
out->slot = slot;
out->nslot = nslot;
out->cap = fs->cap;
out->ncap = fs->ncap;
out->final = fs->final;
/*
* if the sub-term at pi is not in the frontier,
* then we do not reduce the frontier.
*/
if (c == NULL)
return out;
switch (exprop(c->pat)) {
case Ovar:
case Ogap:
/*
* if the pattern at the sub-term pi of this frontier is not a constructor,
* then we do not reduce the frontier.
*/
return out;
default:
break;
}
/*
* if constructor at the path pi is not the constructor we want to project,
* then return null.
*/
if (!pateq(pat, c->pat))
return NULL;
return out;
}
/* compile implements the algorithm outlined in the paper
* "When Do Match-Compilation Heuristics Matter?" by Kevin Scott and Norman Ramsey
* It generates either a TEST or MATCH (accept=1) dtree, where MATCH is the base case.
*
* Summary:
* 1. if the first Frontier of the input list of Frontiers does not contain any
* non-wildcard pattern, return a MATCH dtree (accept=1)
* 2. for each call to the function, it will select a Path from
* the first match clause in the input Frontiers.
* 3. scan the input frontiers 'vertically' at the selected Path to form a set
* of unique constructors. (the list 'cs')
* 4. for each constructor in 'cs', recursively compile the 'projected' frontiers,
* which is roughly the frontiers minus the slot at the Path.
* 5. recursively compile the remaining Frontiers (if any) corresponding to the matches
* rules with a wildcard at the selected Path.
* 6. return a new dtree, where the compiled outputs at step 4 form the outgoing edges
* (dt->next), and the one produced at step 5 serves as the default edage (dt->any)
*
* NOTE:
* a. how we select the Path at the step 2 is determined by heuristics.
* b. we don't expand the frontiers at the 'project' step as the reference paper does.
* rather, we separate the whole compile algorithm into two phases:
* 1) construction of the initial frontiers by 'addrec'.
* 2) construction of the decision tree (with the generated frontiers) by 'compile'
*/
static Dtree *
compile(Frontier **frontier, size_t nfrontier)
{
size_t i, j, k;
Dtree *dt, *out, **edge, *any;
Frontier *fs, **row, **defaults ;
Node **cs, **pat;
Slot *slot, *s;
size_t ncs, ncons, nrow, nedge, ndefaults, npat;
assert(nfrontier > 0);
fs = frontier[0];
/* scan constructors horizontally */
ncons = 0;
for (i = 0; i < fs->nslot; i++) {
switch (exprop(fs->slot[i]->pat)) {
case Ovar:
case Ogap:
break;
default:
ncons++;
}
}
if (ncons == 0) {
fs->final->refcnt++;
return fs->final;
}
assert(fs->nslot > 0);
/* NOTE:
* at the moment we have not implemented any smarter heuristics described in the papers.
* we always select the first found constructor, i.e. the top-left one.
*/
slot = NULL;
for (i = 0; i < fs->nslot; i++) {
switch (exprop(fs->slot[i]->pat)) {
case Ovar:
case Ogap:
continue;
default:
slot = fs->slot[i];
goto pi_found;
}
}
pi_found:
/* scan constructors vertically at pi to create the set 'CS' */
cs = NULL;
ncs = 0;
for (i = 0; i < nfrontier; i++) {
fs = frontier[i];
for (j = 0; j < fs->nslot; j++) {
s = fs->slot[j];
switch (exprop(s->pat)) {
case Ovar:
case Ogap:
break;
case Olit:
if (patheq(slot->path, s->path)) {
/* NOTE:
* we could use a hash table, but given that the n is usually small,
* an exhaustive search would suffice.
*/
/* look for a duplicate entry to skip it; we want a unique set of constructors. */
for (k = 0; k < ncs; k++) {
if (pateq(cs[k], s->pat))
break;
}
if (ncs == 0 || k == ncs)
lappend(&cs, &ncs, s->pat);
}
break;
default:
assert(0);
}
}
}
/* project a new frontier for each selected constructor */
edge = NULL;
nedge = 0;
pat = NULL;
npat = 0;
for (i = 0; i < ncs; i++) {
row = NULL;
nrow = 0;
for (j = 0; j < nfrontier; j++) {
fs = frontier[j];
fs = project(cs[i], slot->path, slot->load, frontier[j]);
if (fs != NULL)
lappend(&row, &nrow, fs);
}
if (nrow > 0) {
dt = compile(row, nrow);
lappend(&edge, &nedge, dt);
lappend(&pat, &npat, cs[i]);
}
}
/* compile the defaults */
defaults = NULL;
ndefaults = 0;
for (i = 0; i < nfrontier; i++) {
fs = frontier[i];
k = -1;
for (j = 0; j < fs->nslot; j++) {
/* locate the occurrence of pi in fs */
if (patheq(slot->path, fs->slot[j]->path))
k = j;
}
if (k == -1 || exprop(fs->slot[k]->pat) == Ovar || exprop(fs->slot[k]->pat) == Ogap)
lappend(&defaults, &ndefaults, fs);
}
if (ndefaults)
any = compile(defaults, ndefaults);
else
any = NULL;
/* construct the result dtree */
out = NULL;
/* TODO
* use a hash table to avoid the quadratic complexity
* when we have a large N and the bottleneck becomes obvious.
*/
for (i = 0; i < ndtree; i++) {
if (!dtree[i]->accept && dtreusable(dtree[i], slot->load, pat, npat, edge, nedge, any)) {
out = dtree[i];
out->refcnt++;
break;
}
}
if (out == NULL) {
out = mkdtree(slot->pat->loc, genlbl(slot->pat->loc));
out->refcnt++;
}
out->load = slot->load;
out->npat = npat,
out->pat = pat,
out->nnext = nedge;
out->next = edge;
out->any = any;
switch (exprop(slot->load)) {
case Outag:
out->nconstructors = nconstructors(tybase(exprtype(slot->load->expr.args[0])));
break;
case Oudata:
case Omemb:
case Otupget:
case Oidx:
case Oderef:
case Ovar:
out->nconstructors = nconstructors(tybase(exprtype(slot->load)));
break;
default:
fatal(slot->pat, "unsupported pattern %s of type %s", opstr[exprop(slot->pat)], tystr(exprtype(slot->pat)));
}
return out;
}
static int
verifymatch(Dtree *t)
{
size_t i;
int ret;
if (t->accept)
return 1;
ret = 0;
if (t->nnext == t->nconstructors || t->any)
ret = 1;
for (i = 0; i < t->nnext; i++)
if (!verifymatch(t->next[i]))
ret = 0;
return ret;
}
static size_t
dtheight(Dtree *dt)
{
size_t i, h, m;
if (dt == NULL)
return 0;
if (dt->accept)
return 0;
m = 0;
for (i = 0; i < dt->nnext; i++) {
h = dtheight(dt->next[i]);
if (h > m)
m = h;
}
h = dtheight(dt->any);
if (h > m)
m = h;
return m+1;
}
static size_t
refsum(Dtree *dt)
{
size_t i;
size_t sum;
if (dt == NULL)
return 0;
dt->emitted = 1;
/* NOTE
* MATCH nodes are always pre-allocated and shared,
* so counted as 1 for the size measurement.
*/
if (dt->accept)
return 1;
sum = 0;
for (i = 0; i < dt->nnext; i++)
if (!dt->next[i]->emitted)
sum += refsum(dt->next[i]);
if (dt->any && !dt->any->emitted)
sum += refsum(dt->any);
return dt->refcnt + sum;
}
static void
clearemit(Dtree *dt)
{
size_t i;
if (dt == NULL)
return;
for (i = 0; i < dt->nnext; i++)
clearemit(dt->next[i]);
clearemit(dt->any);
dt->emitted = 0;
}
static int
capcompatible(Node *a, Node *b)
{
Node *pa, *pb, *va, *vb;
pa = a->expr.args[0];
pb = b->expr.args[0];
va = a->expr.args[1];
vb = b->expr.args[1];
return pa->expr.did == pb->expr.did && tyeq(exprtype(va), exprtype(vb));
}
Dtree *
gendtree(Node *m, Node *val, Node **lbl, size_t nlbl)
{
Dtree *root;
Node **pat;
size_t npat;
size_t i, j;
Frontier **frontier, *cur, *last;
size_t nfrontier;
FILE *csv;
char *dbgloc, *dbgfn, *dbgln;
ndtree = 0;
dtree = NULL;
pat = m->matchstmt.matches;
npat = m->matchstmt.nmatches;
frontier = NULL;
nfrontier = 0;
for (i = 0; i < npat; i++) {
genfrontier(i, val, pat[i]->match.pat, lbl[i], &frontier, &nfrontier);
}
/* to determine if two different sets of captures come from a or-pattern, which is NOT allowed. */
last = NULL;
for (i = 0; i < nfrontier; i++) {
cur = frontier[i];
if (last && last->i == cur->i) {
if (last->ncap != cur->ncap)
fatal(pat[cur->i], "number of wildcard variables in the or-patterns are not equal (%d != %d)", last->ncap, cur->ncap);
for (j = 0; j < cur->ncap; j++) {
if (!capcompatible(last->cap[j], cur->cap[j]))
fatal(pat[cur->i], "wildcard variables have different types in the or-patterns");
}
}
/*
* If the match arm does not have or-pattern, we can
* insert the assignements of the captures at the
* beginning of the associated block. Otherwise,
* the captures can bind different locations with
* the same identifier in thehe or-patterns, and
* thus the assignments must be carried out before
* jumping into the block. For this reason, in the
* case of having or-pattern, we store the
* information of captures in the dtree MATCH node
* and delegate the insertion of the captures
* assignments to the ir generation of dtree
*/
if (cur->hasorpat) {
cur->final->cap = cur->cap;
cur->final->ncap = cur->ncap;
} else {
addcapture(pat[cur->i]->match.block, cur->cap, cur->ncap);
}
last = cur;
}
root = compile(frontier, nfrontier);
for (i = 0; i < nfrontier; i++)
if (frontier[i]->final->refcnt == 0)
fatal(pat[frontier[i]->i], "pattern matched by earlier case");
if (debugopt['M'] || getenv("M")) {
dbgloc = strdup(getenv("M"));
if (strchr(dbgloc, '@')) {
dbgfn = strtok(dbgloc, "@");
dbgln = strtok(NULL, "@")+1; /* offset by 1 to skip the charactor 'L' */
if (!strcmp(fname(m->loc), dbgfn) && lnum(m->loc) == strtol(dbgln, 0, 0))
dtreedump(stdout, root);
}
else
dtreedump(stdout, root);
}
if (!verifymatch(root)) {
fatal(m, "nonexhaustive pattern set in match statement");
}
if (getenv("MATCH_STATS")) {
csv = fopen("match.csv", "a");
assert(csv != NULL);
fprintf(csv, "%s@L%d, %ld, %zd, %zd\n", fname(m->loc), lnum(m->loc), refsum(root), ndtree, dtheight(root));
fclose(csv);
/* clear 'emitted' so it can be reused by genmatchcode. */
clearemit(root);
}
return root;
}
void
genmatchcode(Dtree *dt, Node ***out, size_t *nout)
{
Node *jmp, *eq, *fail;
Node *next;
int emit;
size_t i;
if (dt->emitted)
return;
dt->emitted = 1;
/* the we jump to the accept label when generating the parent */
if (dt->accept) {
jmp = mkexpr(dt->loc, Ojmp, dt->lbl, NULL);
jmp->expr.type = mktype(dt->loc, Tyvoid);
lappend(out, nout, jmp);
return;
}
lappend(out, nout, dt->lbl);
for (i = 0; i < dt->nnext; i++) {
if (i == dt->nnext - 1 && dt->any) {
fail = dt->any->lbl;
emit = 0;
} else {
fail = genlbl(dt->loc);
emit = 1;
}
if (dt->next[i]->accept && dt->next[i]->ncap > 0) {
next = genlbl(dt->next[i]->loc);
} else {
next = dt->next[i]->lbl;
}
eq = mkexpr(dt->loc, Oeq, dt->load, dt->pat[i], NULL);
eq->expr.type = mktype(dt->loc, Tybool);
jmp = mkexpr(dt->loc, Ocjmp, eq, next, fail, NULL);
jmp->expr.type = mktype(dt->loc, Tyvoid);
lappend(out, nout, jmp);
if (dt->next[i]->accept && dt->next[i]->ncap > 0) {
lappend(out, nout, next);
lcat(out, nout, dt->next[i]->cap, dt->next[i]->ncap);
jmp = mkexpr(dt->loc, Ojmp, dt->next[i]->lbl, NULL);
jmp->expr.type = mktype(dt->loc, Tyvoid);
lappend(out, nout, jmp);
}
genmatchcode(dt->next[i], out, nout);
if (emit)
lappend(out, nout, fail);
}
if (dt->any) {
jmp = mkexpr(dt->loc, Ojmp, dt->any->lbl, NULL);
jmp->expr.type = mktype(dt->loc, Tyvoid);
lappend(out, nout, jmp);
genmatchcode(dt->any, out, nout);
}
}
void
genonematch(Node *pat, Node *val, Node *iftrue, Node *iffalse, Node ***out, size_t *nout, Node ***cap, size_t *ncap)
{
Frontier **frontier;
size_t nfrontier;
Dtree *root;
ndtree = 0;
frontier = NULL;
nfrontier = 0;
genfrontier(0, val, pat, iftrue, &frontier, &nfrontier);
lcat(cap, ncap, frontier[0]->cap, frontier[0]->ncap);
genfrontier(1, val, mkexpr(iffalse->loc, Ogap, NULL), iffalse, &frontier, &nfrontier);
root = compile(frontier, nfrontier);
genmatchcode(root, out, nout);
}
void
genmatch(Node *m, Node *val, Node ***out, size_t *nout)
{
Node **pat, **lbl, *end, *endlbl;
size_t npat, nlbl, i;
Dtree *dt;
lbl = NULL;
nlbl = 0;
pat = m->matchstmt.matches;
npat = m->matchstmt.nmatches;
for (i = 0; i < npat; i++)
lappend(&lbl, &nlbl, genlbl(pat[i]->match.block->loc));
endlbl = genlbl(m->loc);
dt = gendtree(m, val, lbl, nlbl);
genmatchcode(dt, out, nout);
for (i = 0; i < npat; i++) {
end = mkexpr(pat[i]->loc, Ojmp, endlbl, NULL);
end->expr.type = mktype(end->loc, Tyvoid);
lappend(out, nout, lbl[i]);
lappend(out, nout, pat[i]->match.block);
lappend(out, nout, end);
}
lappend(out, nout, endlbl);
if (debugopt['m']) {
dtreedump(stdout, dt);
for (i = 0; i < *nout; i++)
dumpn((*out)[i], stdout);
}
}