diff options
author | Russ Cox <rsc@golang.org> | 2014-02-13 20:59:39 -0500 |
---|---|---|
committer | Russ Cox <rsc@golang.org> | 2014-02-13 20:59:39 -0500 |
commit | e0ed119d47728176de20aedeb519e6b470e7e411 (patch) | |
tree | eaaf55c2dd390512ef6c54ada8e4bab5b7c83842 /test | |
parent | 627d914dff9f9b31d835a6aaa57073364c13638a (diff) | |
download | go-e0ed119d47728176de20aedeb519e6b470e7e411.tar.gz |
cmd/gc: distinguish unnamed vs blank-named return variables better
Before, an unnamed return value turned into an ONAME node n with n->sym
named ~anon%d, and n->orig == n.
A blank-named return value turned into an ONAME node n with n->sym
named ~anon%d but n->orig == the original blank n. Code generation and
printing uses n->orig, so that this node formatted as _.
But some code does not use n->orig. In particular the liveness code does
not know about the n->orig convention and so mishandles blank identifiers.
It is possible to fix but seemed better to avoid the confusion entirely.
Now the first kind of node is named ~r%d and the second ~b%d; both have
n->orig == n, so that it doesn't matter whether code uses n or n->orig.
After this change the ->orig field is only used for other kinds of expressions,
not for ONAME nodes.
This requires distinguishing ~b from ~r names in a few places that care.
It fixes a liveness analysis bug without actually changing the liveness code.
TBR=ken2
CC=golang-codereviews
https://codereview.appspot.com/63630043
Diffstat (limited to 'test')
-rw-r--r-- | test/escape5.go | 8 | ||||
-rw-r--r-- | test/live.go | 7 |
2 files changed, 11 insertions, 4 deletions
diff --git a/test/escape5.go b/test/escape5.go index c9646872d..a33daeee1 100644 --- a/test/escape5.go +++ b/test/escape5.go @@ -17,19 +17,19 @@ func leaktoret(p *int) *int { // ERROR "leaking param: p to result" return p } -func leaktoret2(p *int) (*int, *int) { // ERROR "leaking param: p to result .anon1" "leaking param: p to result .anon2" +func leaktoret2(p *int) (*int, *int) { // ERROR "leaking param: p to result ~r1" "leaking param: p to result ~r2" return p, p } -func leaktoret22(p, q *int) (*int, *int) { // ERROR "leaking param: p to result .anon2" "leaking param: q to result .anon3" +func leaktoret22(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r2" "leaking param: q to result ~r3" return p, q } -func leaktoret22b(p, q *int) (*int, *int) { // ERROR "leaking param: p to result .anon3" "leaking param: q to result .anon2" +func leaktoret22b(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r3" "leaking param: q to result ~r2" return leaktoret22(q, p) } -func leaktoret22c(p, q *int) (*int, *int) { // ERROR "leaking param: p to result .anon3" "leaking param: q to result .anon2" +func leaktoret22c(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r3" "leaking param: q to result ~r2" r, s := leaktoret22(q, p) return r, s } diff --git a/test/live.go b/test/live.go index dc2ec86fd..c0ea13129 100644 --- a/test/live.go +++ b/test/live.go @@ -79,3 +79,10 @@ func f5(b1 bool) { } print(**z) // ERROR "live at call to printint: x y$" } + +// confusion about the _ result used to cause spurious "live at entry to f6: _". + +func f6() (_, y string) { + y = "hello" + return +} |