diff options
| author | Keith Randall <khr@golang.org> | 2016-03-08 20:09:48 -0800 |
|---|---|---|
| committer | Keith Randall <khr@golang.org> | 2016-03-11 00:56:04 +0000 |
| commit | 31d13f479a19ca6e07ad60c441298c6eca04eeb2 (patch) | |
| tree | 11a9484b53aab5f4667c4e56d865a35e1f73eab1 /src/cmd | |
| parent | fb9aafac97649a11301b78ee9e2139804c52b528 (diff) | |
| download | go-31d13f479a19ca6e07ad60c441298c6eca04eeb2.tar.xz | |
cmd/compile: don't use PPARAMOUT names for temps
The location of VARDEFs is incorrect for PPARAMOUT variables
which are also used as temporary locations. We put in VARDEFs
when setting the variable at return time, but when the location
is also used as a temporary the lifetime values are wrong.
Fix copyelim to update the names map properly. This is a
real name bug fix which, as a result, allows me to
write a reasonable test to trigger the PPARAMOUT bug.
This is kind of a band-aid fix for #14591. A more pricipled
fix (which allows values to be stored in the return variable
earlier than the return point) will be harder.
Fixes #14591
Change-Id: I7df8ae103a982d1f218ed704c080d7b83cdcfdd9
Reviewed-on: https://go-review.googlesource.com/20457
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Diffstat (limited to 'src/cmd')
| -rw-r--r-- | src/cmd/compile/internal/gc/ssa.go | 5 | ||||
| -rw-r--r-- | src/cmd/compile/internal/ssa/copyelim.go | 2 |
2 files changed, 6 insertions, 1 deletions
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go index afba7db638..87d2374216 100644 --- a/src/cmd/compile/internal/gc/ssa.go +++ b/src/cmd/compile/internal/gc/ssa.go @@ -3608,6 +3608,11 @@ func (s *state) addNamedValue(n *Node, v *ssa.Value) { // pseudos in the right place when we spill to these nodes. return } + if n.Class == PPARAMOUT { + // Don't track named output values. This prevents return values + // from being assigned too early. See #14591 and #14762. TODO: allow this. + return + } if n.Class == PAUTO && n.Xoffset != 0 { s.Fatalf("AUTO var with offset %s %d", n, n.Xoffset) } diff --git a/src/cmd/compile/internal/ssa/copyelim.go b/src/cmd/compile/internal/ssa/copyelim.go index cfeff21e84..5488134122 100644 --- a/src/cmd/compile/internal/ssa/copyelim.go +++ b/src/cmd/compile/internal/ssa/copyelim.go @@ -28,7 +28,7 @@ func copyelim(f *Func) { x = x.Args[0] } if x != v { - values[i] = v + values[i] = x } } } |