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Diffstat (limited to 'src/cmd/gc/align.c')
-rw-r--r--src/cmd/gc/align.c653
1 files changed, 653 insertions, 0 deletions
diff --git a/src/cmd/gc/align.c b/src/cmd/gc/align.c
new file mode 100644
index 000000000..14c1c4a8d
--- /dev/null
+++ b/src/cmd/gc/align.c
@@ -0,0 +1,653 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "go.h"
+
+/*
+ * machine size and rounding
+ * alignment is dictated around
+ * the size of a pointer, set in betypeinit
+ * (see ../6g/galign.c).
+ */
+
+static int defercalc;
+
+uint32
+rnd(uint32 o, uint32 r)
+{
+ if(r < 1 || r > 8 || (r&(r-1)) != 0)
+ fatal("rnd");
+ return (o+r-1)&~(r-1);
+}
+
+static void
+offmod(Type *t)
+{
+ Type *f;
+ int32 o;
+
+ o = 0;
+ for(f=t->type; f!=T; f=f->down) {
+ if(f->etype != TFIELD)
+ fatal("offmod: not TFIELD: %lT", f);
+ f->width = o;
+ o += widthptr;
+ if(o >= MAXWIDTH) {
+ yyerror("interface too large");
+ o = widthptr;
+ }
+ }
+}
+
+static vlong
+widstruct(Type *errtype, Type *t, vlong o, int flag)
+{
+ Type *f;
+ int32 w, maxalign;
+
+ maxalign = flag;
+ if(maxalign < 1)
+ maxalign = 1;
+ for(f=t->type; f!=T; f=f->down) {
+ if(f->etype != TFIELD)
+ fatal("widstruct: not TFIELD: %lT", f);
+ dowidth(f->type);
+ if(f->type->align > maxalign)
+ maxalign = f->type->align;
+ if(f->type->width < 0)
+ fatal("invalid width %lld", f->type->width);
+ w = f->type->width;
+ if(f->type->align > 0)
+ o = rnd(o, f->type->align);
+ f->width = o; // really offset for TFIELD
+ if(f->nname != N) {
+ // this same stackparam logic is in addrescapes
+ // in typecheck.c. usually addrescapes runs after
+ // widstruct, in which case we could drop this,
+ // but function closure functions are the exception.
+ if(f->nname->stackparam) {
+ f->nname->stackparam->xoffset = o;
+ f->nname->xoffset = 0;
+ } else
+ f->nname->xoffset = o;
+ }
+ o += w;
+ if(o >= MAXWIDTH) {
+ yyerror("type %lT too large", errtype);
+ o = 8; // small but nonzero
+ }
+ }
+ // final width is rounded
+ if(flag)
+ o = rnd(o, maxalign);
+ t->align = maxalign;
+
+ // type width only includes back to first field's offset
+ if(t->type == T)
+ t->width = 0;
+ else
+ t->width = o - t->type->width;
+ return o;
+}
+
+void
+dowidth(Type *t)
+{
+ int32 et;
+ int64 w;
+ int lno;
+ Type *t1;
+
+ if(widthptr == 0)
+ fatal("dowidth without betypeinit");
+
+ if(t == T)
+ return;
+
+ if(t->width > 0)
+ return;
+
+ if(t->width == -2) {
+ lno = lineno;
+ lineno = t->lineno;
+ yyerror("invalid recursive type %T", t);
+ t->width = 0;
+ lineno = lno;
+ return;
+ }
+
+ // defer checkwidth calls until after we're done
+ defercalc++;
+
+ lno = lineno;
+ lineno = t->lineno;
+ t->width = -2;
+ t->align = 0;
+
+ et = t->etype;
+ switch(et) {
+ case TFUNC:
+ case TCHAN:
+ case TMAP:
+ case TSTRING:
+ break;
+
+ default:
+ /* simtype == 0 during bootstrap */
+ if(simtype[t->etype] != 0)
+ et = simtype[t->etype];
+ break;
+ }
+
+ w = 0;
+ switch(et) {
+ default:
+ fatal("dowidth: unknown type: %T", t);
+ break;
+
+ /* compiler-specific stuff */
+ case TINT8:
+ case TUINT8:
+ case TBOOL: // bool is int8
+ w = 1;
+ break;
+ case TINT16:
+ case TUINT16:
+ w = 2;
+ break;
+ case TINT32:
+ case TUINT32:
+ case TFLOAT32:
+ w = 4;
+ break;
+ case TINT64:
+ case TUINT64:
+ case TFLOAT64:
+ case TCOMPLEX64:
+ w = 8;
+ t->align = widthptr;
+ break;
+ case TCOMPLEX128:
+ w = 16;
+ t->align = widthptr;
+ break;
+ case TPTR32:
+ w = 4;
+ checkwidth(t->type);
+ break;
+ case TPTR64:
+ w = 8;
+ checkwidth(t->type);
+ break;
+ case TUNSAFEPTR:
+ w = widthptr;
+ break;
+ case TINTER: // implemented as 2 pointers
+ w = 2*widthptr;
+ t->align = widthptr;
+ offmod(t);
+ break;
+ case TCHAN: // implemented as pointer
+ w = widthptr;
+ checkwidth(t->type);
+
+ // make fake type to check later to
+ // trigger channel argument check.
+ t1 = typ(TCHANARGS);
+ t1->type = t;
+ checkwidth(t1);
+ break;
+ case TCHANARGS:
+ t1 = t->type;
+ dowidth(t->type); // just in case
+ if(t1->type->width >= (1<<16))
+ yyerror("channel element type too large (>64kB)");
+ t->width = 1;
+ break;
+ case TMAP: // implemented as pointer
+ w = widthptr;
+ checkwidth(t->type);
+ checkwidth(t->down);
+ break;
+ case TFORW: // should have been filled in
+ yyerror("invalid recursive type %T", t);
+ w = 1; // anything will do
+ break;
+ case TANY:
+ // dummy type; should be replaced before use.
+ if(!debug['A'])
+ fatal("dowidth any");
+ w = 1; // anything will do
+ break;
+ case TSTRING:
+ if(sizeof_String == 0)
+ fatal("early dowidth string");
+ w = sizeof_String;
+ t->align = widthptr;
+ break;
+ case TARRAY:
+ if(t->type == T)
+ break;
+ if(t->bound >= 0) {
+ uint64 cap;
+
+ dowidth(t->type);
+ if(t->type->width != 0) {
+ cap = (MAXWIDTH-1) / t->type->width;
+ if(t->bound > cap)
+ yyerror("type %lT larger than address space", t);
+ }
+ w = t->bound * t->type->width;
+ t->align = t->type->align;
+ }
+ else if(t->bound == -1) {
+ w = sizeof_Array;
+ checkwidth(t->type);
+ t->align = widthptr;
+ }
+ else if(t->bound == -100)
+ yyerror("use of [...] array outside of array literal");
+ else
+ fatal("dowidth %T", t); // probably [...]T
+ break;
+
+ case TSTRUCT:
+ if(t->funarg)
+ fatal("dowidth fn struct %T", t);
+ w = widstruct(t, t, 0, 1);
+ break;
+
+ case TFUNC:
+ // make fake type to check later to
+ // trigger function argument computation.
+ t1 = typ(TFUNCARGS);
+ t1->type = t;
+ checkwidth(t1);
+
+ // width of func type is pointer
+ w = widthptr;
+ break;
+
+ case TFUNCARGS:
+ // function is 3 cated structures;
+ // compute their widths as side-effect.
+ t1 = t->type;
+ w = widstruct(t->type, *getthis(t1), 0, 0);
+ w = widstruct(t->type, *getinarg(t1), w, widthptr);
+ w = widstruct(t->type, *getoutarg(t1), w, widthptr);
+ t1->argwid = w;
+ if(w%widthptr)
+ warn("bad type %T %d\n", t1, w);
+ t->align = 1;
+ break;
+ }
+
+ t->width = w;
+ if(t->align == 0) {
+ if(w > 8 || (w&(w-1)) != 0)
+ fatal("invalid alignment for %T", t);
+ t->align = w;
+ }
+ lineno = lno;
+
+ if(defercalc == 1)
+ resumecheckwidth();
+ else
+ --defercalc;
+}
+
+/*
+ * when a type's width should be known, we call checkwidth
+ * to compute it. during a declaration like
+ *
+ * type T *struct { next T }
+ *
+ * it is necessary to defer the calculation of the struct width
+ * until after T has been initialized to be a pointer to that struct.
+ * similarly, during import processing structs may be used
+ * before their definition. in those situations, calling
+ * defercheckwidth() stops width calculations until
+ * resumecheckwidth() is called, at which point all the
+ * checkwidths that were deferred are executed.
+ * dowidth should only be called when the type's size
+ * is needed immediately. checkwidth makes sure the
+ * size is evaluated eventually.
+ */
+typedef struct TypeList TypeList;
+struct TypeList {
+ Type *t;
+ TypeList *next;
+};
+
+static TypeList *tlfree;
+static TypeList *tlq;
+
+void
+checkwidth(Type *t)
+{
+ TypeList *l;
+
+ if(t == T)
+ return;
+
+ // function arg structs should not be checked
+ // outside of the enclosing function.
+ if(t->funarg)
+ fatal("checkwidth %T", t);
+
+ if(!defercalc) {
+ dowidth(t);
+ return;
+ }
+ if(t->deferwidth)
+ return;
+ t->deferwidth = 1;
+
+ l = tlfree;
+ if(l != nil)
+ tlfree = l->next;
+ else
+ l = mal(sizeof *l);
+
+ l->t = t;
+ l->next = tlq;
+ tlq = l;
+}
+
+void
+defercheckwidth(void)
+{
+ // we get out of sync on syntax errors, so don't be pedantic.
+ if(defercalc && nerrors == 0)
+ fatal("defercheckwidth");
+ defercalc = 1;
+}
+
+void
+resumecheckwidth(void)
+{
+ TypeList *l;
+
+ if(!defercalc)
+ fatal("resumecheckwidth");
+ for(l = tlq; l != nil; l = tlq) {
+ l->t->deferwidth = 0;
+ tlq = l->next;
+ dowidth(l->t);
+ l->next = tlfree;
+ tlfree = l;
+ }
+ defercalc = 0;
+}
+
+void
+typeinit(void)
+{
+ int i, etype, sameas;
+ Type *t;
+ Sym *s, *s1;
+
+ if(widthptr == 0)
+ fatal("typeinit before betypeinit");
+
+ for(i=0; i<NTYPE; i++)
+ simtype[i] = i;
+
+ types[TPTR32] = typ(TPTR32);
+ dowidth(types[TPTR32]);
+
+ types[TPTR64] = typ(TPTR64);
+ dowidth(types[TPTR64]);
+
+ t = typ(TUNSAFEPTR);
+ types[TUNSAFEPTR] = t;
+ t->sym = pkglookup("Pointer", unsafepkg);
+ t->sym->def = typenod(t);
+
+ dowidth(types[TUNSAFEPTR]);
+
+ tptr = TPTR32;
+ if(widthptr == 8)
+ tptr = TPTR64;
+
+ for(i=TINT8; i<=TUINT64; i++)
+ isint[i] = 1;
+ isint[TINT] = 1;
+ isint[TUINT] = 1;
+ isint[TUINTPTR] = 1;
+
+ isfloat[TFLOAT32] = 1;
+ isfloat[TFLOAT64] = 1;
+
+ iscomplex[TCOMPLEX64] = 1;
+ iscomplex[TCOMPLEX128] = 1;
+
+ isptr[TPTR32] = 1;
+ isptr[TPTR64] = 1;
+
+ isforw[TFORW] = 1;
+
+ issigned[TINT] = 1;
+ issigned[TINT8] = 1;
+ issigned[TINT16] = 1;
+ issigned[TINT32] = 1;
+ issigned[TINT64] = 1;
+
+ /*
+ * initialize okfor
+ */
+ for(i=0; i<NTYPE; i++) {
+ if(isint[i] || i == TIDEAL) {
+ okforeq[i] = 1;
+ okforcmp[i] = 1;
+ okforarith[i] = 1;
+ okforadd[i] = 1;
+ okforand[i] = 1;
+ okforconst[i] = 1;
+ issimple[i] = 1;
+ minintval[i] = mal(sizeof(*minintval[i]));
+ maxintval[i] = mal(sizeof(*maxintval[i]));
+ }
+ if(isfloat[i]) {
+ okforeq[i] = 1;
+ okforcmp[i] = 1;
+ okforadd[i] = 1;
+ okforarith[i] = 1;
+ okforconst[i] = 1;
+ issimple[i] = 1;
+ minfltval[i] = mal(sizeof(*minfltval[i]));
+ maxfltval[i] = mal(sizeof(*maxfltval[i]));
+ }
+ if(iscomplex[i]) {
+ okforeq[i] = 1;
+ okforadd[i] = 1;
+ okforarith[i] = 1;
+ okforconst[i] = 1;
+ issimple[i] = 1;
+ }
+ }
+
+ issimple[TBOOL] = 1;
+
+ okforadd[TSTRING] = 1;
+
+ okforbool[TBOOL] = 1;
+
+ okforcap[TARRAY] = 1;
+ okforcap[TCHAN] = 1;
+
+ okforconst[TBOOL] = 1;
+ okforconst[TSTRING] = 1;
+
+ okforlen[TARRAY] = 1;
+ okforlen[TCHAN] = 1;
+ okforlen[TMAP] = 1;
+ okforlen[TSTRING] = 1;
+
+ okforeq[TPTR32] = 1;
+ okforeq[TPTR64] = 1;
+ okforeq[TUNSAFEPTR] = 1;
+ okforeq[TINTER] = 1;
+ okforeq[TMAP] = 1;
+ okforeq[TCHAN] = 1;
+ okforeq[TFUNC] = 1;
+ okforeq[TSTRING] = 1;
+ okforeq[TBOOL] = 1;
+ okforeq[TARRAY] = 1; // refined in typecheck
+
+ okforcmp[TSTRING] = 1;
+
+ for(i=0; i<nelem(okfor); i++)
+ okfor[i] = okfornone;
+
+ // binary
+ okfor[OADD] = okforadd;
+ okfor[OAND] = okforand;
+ okfor[OANDAND] = okforbool;
+ okfor[OANDNOT] = okforand;
+ okfor[ODIV] = okforarith;
+ okfor[OEQ] = okforeq;
+ okfor[OGE] = okforcmp;
+ okfor[OGT] = okforcmp;
+ okfor[OLE] = okforcmp;
+ okfor[OLT] = okforcmp;
+ okfor[OMOD] = okforand;
+ okfor[OMUL] = okforarith;
+ okfor[ONE] = okforeq;
+ okfor[OOR] = okforand;
+ okfor[OOROR] = okforbool;
+ okfor[OSUB] = okforarith;
+ okfor[OXOR] = okforand;
+ okfor[OLSH] = okforand;
+ okfor[ORSH] = okforand;
+
+ // unary
+ okfor[OCOM] = okforand;
+ okfor[OMINUS] = okforarith;
+ okfor[ONOT] = okforbool;
+ okfor[OPLUS] = okforarith;
+
+ // special
+ okfor[OCAP] = okforcap;
+ okfor[OLEN] = okforlen;
+
+ // comparison
+ iscmp[OLT] = 1;
+ iscmp[OGT] = 1;
+ iscmp[OGE] = 1;
+ iscmp[OLE] = 1;
+ iscmp[OEQ] = 1;
+ iscmp[ONE] = 1;
+
+ mpatofix(maxintval[TINT8], "0x7f");
+ mpatofix(minintval[TINT8], "-0x80");
+ mpatofix(maxintval[TINT16], "0x7fff");
+ mpatofix(minintval[TINT16], "-0x8000");
+ mpatofix(maxintval[TINT32], "0x7fffffff");
+ mpatofix(minintval[TINT32], "-0x80000000");
+ mpatofix(maxintval[TINT64], "0x7fffffffffffffff");
+ mpatofix(minintval[TINT64], "-0x8000000000000000");
+
+ mpatofix(maxintval[TUINT8], "0xff");
+ mpatofix(maxintval[TUINT16], "0xffff");
+ mpatofix(maxintval[TUINT32], "0xffffffff");
+ mpatofix(maxintval[TUINT64], "0xffffffffffffffff");
+
+ /* f is valid float if min < f < max. (min and max are not themselves valid.) */
+ mpatoflt(maxfltval[TFLOAT32], "33554431p103"); /* 2^24-1 p (127-23) + 1/2 ulp*/
+ mpatoflt(minfltval[TFLOAT32], "-33554431p103");
+ mpatoflt(maxfltval[TFLOAT64], "18014398509481983p970"); /* 2^53-1 p (1023-52) + 1/2 ulp */
+ mpatoflt(minfltval[TFLOAT64], "-18014398509481983p970");
+
+ maxfltval[TCOMPLEX64] = maxfltval[TFLOAT32];
+ minfltval[TCOMPLEX64] = minfltval[TFLOAT32];
+ maxfltval[TCOMPLEX128] = maxfltval[TFLOAT64];
+ minfltval[TCOMPLEX128] = minfltval[TFLOAT64];
+
+ /* for walk to use in error messages */
+ types[TFUNC] = functype(N, nil, nil);
+
+ /* types used in front end */
+ // types[TNIL] got set early in lexinit
+ types[TIDEAL] = typ(TIDEAL);
+ types[TINTER] = typ(TINTER);
+
+ /* simple aliases */
+ simtype[TMAP] = tptr;
+ simtype[TCHAN] = tptr;
+ simtype[TFUNC] = tptr;
+ simtype[TUNSAFEPTR] = tptr;
+
+ /* pick up the backend typedefs */
+ for(i=0; typedefs[i].name; i++) {
+ s = lookup(typedefs[i].name);
+ s1 = pkglookup(typedefs[i].name, builtinpkg);
+
+ etype = typedefs[i].etype;
+ if(etype < 0 || etype >= nelem(types))
+ fatal("typeinit: %s bad etype", s->name);
+ sameas = typedefs[i].sameas;
+ if(sameas < 0 || sameas >= nelem(types))
+ fatal("typeinit: %s bad sameas", s->name);
+ simtype[etype] = sameas;
+ minfltval[etype] = minfltval[sameas];
+ maxfltval[etype] = maxfltval[sameas];
+ minintval[etype] = minintval[sameas];
+ maxintval[etype] = maxintval[sameas];
+
+ t = types[etype];
+ if(t != T)
+ fatal("typeinit: %s already defined", s->name);
+
+ t = typ(etype);
+ t->sym = s;
+
+ dowidth(t);
+ types[etype] = t;
+ s1->def = typenod(t);
+ }
+
+ Array_array = rnd(0, widthptr);
+ Array_nel = rnd(Array_array+widthptr, types[TUINT32]->width);
+ Array_cap = rnd(Array_nel+types[TUINT32]->width, types[TUINT32]->width);
+ sizeof_Array = rnd(Array_cap+types[TUINT32]->width, widthptr);
+
+ // string is same as slice wo the cap
+ sizeof_String = rnd(Array_nel+types[TUINT32]->width, widthptr);
+
+ dowidth(types[TSTRING]);
+ dowidth(idealstring);
+}
+
+/*
+ * compute total size of f's in/out arguments.
+ */
+int
+argsize(Type *t)
+{
+ Iter save;
+ Type *fp;
+ int w, x;
+
+ w = 0;
+
+ fp = structfirst(&save, getoutarg(t));
+ while(fp != T) {
+ x = fp->width + fp->type->width;
+ if(x > w)
+ w = x;
+ fp = structnext(&save);
+ }
+
+ fp = funcfirst(&save, t);
+ while(fp != T) {
+ x = fp->width + fp->type->width;
+ if(x > w)
+ w = x;
+ fp = funcnext(&save);
+ }
+
+ w = (w+widthptr-1) & ~(widthptr-1);
+ return w;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2025-07-24 06:23:29 +0000