cybercyst/go
1
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-05-09 17:43:07 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

cmd/gc: handle variable initialization by block move in liveness

Browse Source 
Any initialization of a variable by a block copy or block zeroing
or by multiple assignments (componentwise copying or zeroing
of a multiword variable) needs to emit a VARDEF. These cases were not.

Fixes #7205.

TBR=iant
CC=golang-codereviews
https://golang.org/cl/63650044
This commit is contained in:
Russ Cox 2014-02-13 22:45:16 -05:00
parent 7addda685d
commit 91b1f7cb15
6 changed files with 65 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
src/cmd/5g/cgen.c
View File

@ -1414,6 +1414,7 @@ sgen(Node *n, Node *res, int64 w)
int32 c, odst, osrc;
int dir, align, op;
Prog *p, *ploop;
NodeList *l;
if(debug['g']) {
print("\nsgen w=%lld\n", w);
@ -1439,6 +1440,17 @@ sgen(Node *n, Node *res, int64 w)
return;
}
// Record site of definition of ns for liveness analysis.
if(res->op == ONAME && res->class != PEXTERN)
gvardef(res);
// If copying .args, that's all the results, so record definition sites
// for them for the liveness analysis.
if(res->op == ONAME && strcmp(res->sym->name, ".args") == 0)
for(l = curfn->dcl; l != nil; l = l->next)
if(l->n->class == PPARAMOUT)
gvardef(l->n);
// Avoid taking the address for simple enough types.
if(componentgen(n, res))
return;

12
src/cmd/6g/cgen.c
View File

@ -1337,6 +1337,7 @@ sgen(Node *n, Node *ns, int64 w)
{
Node nodl, nodr, nodsi, noddi, cx, oldcx, tmp;
vlong c, q, odst, osrc;
NodeList *l;
if(debug['g']) {
print("\nsgen w=%lld\n", w);
@ -1349,6 +1350,17 @@ sgen(Node *n, Node *ns, int64 w)
if(w < 0)
fatal("sgen copy %lld", w);
// Record site of definition of ns for liveness analysis.
if(ns->op == ONAME && ns->class != PEXTERN)
gvardef(ns);
// If copying .args, that's all the results, so record definition sites
// for them for the liveness analysis.
if(ns->op == ONAME && strcmp(ns->sym->name, ".args") == 0)
for(l = curfn->dcl; l != nil; l = l->next)
if(l->n->class == PPARAMOUT)
gvardef(l->n);
// Avoid taking the address for simple enough types.
if(componentgen(n, ns))

12
src/cmd/8g/cgen.c
View File

@ -1203,6 +1203,7 @@ sgen(Node *n, Node *res, int64 w)
{
Node dst, src, tdst, tsrc;
int32 c, q, odst, osrc;
NodeList *l;
if(debug['g']) {
print("\nsgen w=%lld\n", w);
@ -1223,6 +1224,17 @@ sgen(Node *n, Node *res, int64 w)
return;
}
// Record site of definition of ns for liveness analysis.
if(res->op == ONAME && res->class != PEXTERN)
gvardef(res);
// If copying .args, that's all the results, so record definition sites
// for them for the liveness analysis.
if(res->op == ONAME && strcmp(res->sym->name, ".args") == 0)
for(l = curfn->dcl; l != nil; l = l->next)
if(l->n->class == PPARAMOUT)
gvardef(l->n);
// Avoid taking the address for simple enough types.
if(componentgen(n, res))
return;

4
src/cmd/gc/pgen.c
View File

@ -34,8 +34,8 @@ makefuncdatasym(char *namefmt, int64 funcdatakind)
void
gvardef(Node *n)
{
if(n == N || !isfat(n->type))
fatal("gvardef: node is not fat");
if(n == N)
fatal("gvardef nil");
switch(n->class) {
case PAUTO:
case PPARAM:

19
src/cmd/gc/plive.c
View File

@ -621,7 +621,7 @@ freecfg(Array *cfg)
static int
isfunny(Node *node)
{
char *names[] = { ".fp", ".args", "_", nil };
char *names[] = { ".fp", ".args", nil };
int i;
if(node->sym != nil && node->sym->name != nil)
@ -696,8 +696,8 @@ progeffects(Prog *prog, Array *vars, Bvec *uevar, Bvec *varkill, Bvec *avarinit)
}
if(info.flags & (LeftRead | LeftWrite | LeftAddr)) {
from = &prog->from;
if (from->node != nil && !isfunny(from->node) && from->sym != nil) {
switch(prog->from.node->class & ~PHEAP) {
if (from->node != nil && from->sym != nil) {
switch(from->node->class & ~PHEAP) {
case PAUTO:
case PPARAM:
case PPARAMOUT:
@ -710,7 +710,7 @@ progeffects(Prog *prog, Array *vars, Bvec *uevar, Bvec *varkill, Bvec *avarinit)
if(info.flags & (LeftRead | LeftAddr))
bvset(uevar, pos);
if(info.flags & LeftWrite)
if(from->node != nil && (!isfat(from->node->type) || prog->as == AVARDEF))
if(from->node != nil && !isfat(from->node->type))
bvset(varkill, pos);
}
}
@ -719,8 +719,8 @@ progeffects(Prog *prog, Array *vars, Bvec *uevar, Bvec *varkill, Bvec *avarinit)
Next:
if(info.flags & (RightRead | RightWrite | RightAddr)) {
to = &prog->to;
if (to->node != nil && to->sym != nil && !isfunny(to->node)) {
switch(prog->to.node->class & ~PHEAP) {
if (to->node != nil && to->sym != nil) {
switch(to->node->class & ~PHEAP) {
case PAUTO:
case PPARAM:
case PPARAMOUT:
@ -728,10 +728,9 @@ Next:
if(pos == -1)
goto Next1;
if(to->node->addrtaken) {
//if(prog->as == AKILL)
// bvset(varkill, pos);
//else
bvset(avarinit, pos);
bvset(avarinit, pos);
if(prog->as == AVARDEF)
bvset(varkill, pos);
} else {
if(info.flags & (RightRead | RightAddr))
bvset(uevar, pos);

18
test/live.go
View File

@ -95,3 +95,21 @@ func f7() (x string) {
return
}
// ignoring block returns used to cause "live at entry to f8: x, y".
func f8() (x, y string) {
return g8()
}
func g8() (string, string)
// ignoring block assignments used to cause "live at entry to f9: x"
// issue 7205
var i9 interface{}
func f9() bool {
g8()
x := i9
return x != 99
}