[dev.ssa] cmd/compile: fixed heap-escaped-paramout
Changed tree generation to correctly use PARAMOUT instead
of PARAM.
Emit Func.Exit before any returns.
Change-Id: I2fa53cc7fad05fb4eea21081ba33d1f66db4ed49
Reviewed-on: https://go-review.googlesource.com/15610
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: David Chase <drchase@google.com>
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 69a9b86..629774c 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -30,6 +30,7 @@
fmt.Println("generating SSA for", name)
dumplist("buildssa-enter", fn.Func.Enter)
dumplist("buildssa-body", fn.Nbody)
+ dumplist("buildssa-exit", fn.Func.Exit)
}
var s state
@@ -43,6 +44,7 @@
s.config = ssa.NewConfig(Thearch.Thestring, &e)
s.f = s.config.NewFunc()
s.f.Name = name
+ s.exitCode = fn.Func.Exit
if name == os.Getenv("GOSSAFUNC") {
// TODO: tempfile? it is handy to have the location
@@ -97,8 +99,8 @@
// TODO this looks wrong for PAUTO|PHEAP, no vardef, but also no definition
aux := &ssa.AutoSymbol{Typ: n.Type, Node: n}
s.decladdrs[n] = s.entryNewValue1A(ssa.OpAddr, Ptrto(n.Type), aux, s.sp)
- case PPARAM | PHEAP: // PPARAMOUT | PHEAP seems to not occur
- // This ends up wrong, have to do it at the PARAM node instead.
+ case PPARAM | PHEAP, PPARAMOUT | PHEAP:
+ // This ends up wrong, have to do it at the PARAM node instead.
case PAUTO, PPARAMOUT:
// processed at each use, to prevent Addr coming
// before the decl.
@@ -122,6 +124,7 @@
// fallthrough to exit
if s.curBlock != nil {
+ s.stmtList(s.exitCode)
m := s.mem()
b := s.endBlock()
b.Kind = ssa.BlockRet
@@ -156,6 +159,9 @@
// Link up variable uses to variable definitions
s.linkForwardReferences()
+ // Don't carry reference this around longer than necessary
+ s.exitCode = nil
+
// Main call to ssa package to compile function
ssa.Compile(s.f)
@@ -207,6 +213,9 @@
// gotos that jump forward; required for deferred checkgoto calls
fwdGotos []*Node
+ // Code that must precede any return
+ // (e.g., copying value of heap-escaped paramout back to true paramout)
+ exitCode *NodeList
// unlabeled break and continue statement tracking
breakTo *ssa.Block // current target for plain break statement
@@ -641,12 +650,14 @@
case ORETURN:
s.stmtList(n.List)
+ s.stmtList(s.exitCode)
m := s.mem()
b := s.endBlock()
b.Kind = ssa.BlockRet
b.Control = m
case ORETJMP:
s.stmtList(n.List)
+ s.stmtList(s.exitCode)
m := s.mem()
b := s.endBlock()
b.Kind = ssa.BlockRetJmp
