qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-11-18 22:55:23 -07:00
Code Releases Activity

implement discussed function wo return statement

Browse Source 
R=r
OCL=15166
CL=15166
This commit is contained in:
Ken Thompson 2008-09-11 15:23:01 -07:00
parent 5ea7649b43
commit d30c9a4be5
2 changed files with 42 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
src/cmd/6g/gen.c
View File

@ -68,8 +68,10 @@ if(newproc == N) {
gclean();
checklabels();
// if(curfn->type->outtuple != 0)
// gins(AGOK, N, N);
if(curfn->type->outtuple != 0) {
nodconst(&nod1, types[TUINT8], 6); // 6 is opcode trap
gins(AINT, &nod1, N);
}
pc->as = ARET; // overwrite AEND
pc->lineno = lineno;

41
src/cmd/gc/walk.c
View File

@ -10,6 +10,38 @@ static Type* sw3(Node*, Type*);
static Node* curfn;
static Node* addtop;
// can this code branch reach the end
// without an undcontitional RETURN
// this is hard, so it is conservative
int
walkret(Node *n)
{
loop:
if(n != N)
switch(n->op) {
case OLIST:
if(n->right == N) {
n = n->left;
goto loop;
}
n = n->right;
goto loop;
// at this point, we have the last
// statement of the function
case OGOTO:
case OPANIC:
case ORETURN:
return 0;
}
// all other statements
// will flow to the end
return 1;
}
void
walk(Node *fn)
{
@ -18,12 +50,15 @@ walk(Node *fn)
curfn = fn;
if(debug['W']) {
snprint(s, sizeof(s), "\nbefore %S", curfn->nname->sym);
dump(s, fn->nbody);
dump(s, curfn->nbody);
}
walkstate(fn->nbody);
if(curfn->type->outtuple)
if(walkret(curfn->nbody))
warn("function ends without a return statement");
walkstate(curfn->nbody);
if(debug['W']) {
snprint(s, sizeof(s), "after %S", curfn->nname->sym);
dump(s, fn->nbody);
dump(s, curfn->nbody);
}
}