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author | Matthew Dempsky <mdempsky@google.com> | 2021-01-04 18:28:55 -0800 |
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committer | Matthew Dempsky <mdempsky@google.com> | 2021-01-05 12:31:18 +0000 |
commit | eb626409d152caabac418eccbe86b49d1fc6a6f5 (patch) | |
tree | 454f3865cdca81592f2a4e8fdef3756fcf23e9a6 /src/cmd/compile/internal/typecheck/func.go | |
parent | c28ca67a961a0c1d149a249918a15ed74c61af27 (diff) | |
download | go-eb626409d152caabac418eccbe86b49d1fc6a6f5.tar.gz go-eb626409d152caabac418eccbe86b49d1fc6a6f5.zip |
[dev.regabi] cmd/compile: simplify CaptureVars
CaptureVars is responsible for deciding whether free variables should
be captured by value or by reference, but currently it also makes up
for some of the short-comings of the frontend symbol resolution /
type-checking algorithms. These are really separate responsibilities,
so move the latter into type-checking where it fits better.
Passes toolstash -cmp.
Change-Id: Iffbd53e83846a9ca9dfb54b597450b8543252850
Reviewed-on: https://go-review.googlesource.com/c/go/+/281534
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Diffstat (limited to 'src/cmd/compile/internal/typecheck/func.go')
-rw-r--r-- | src/cmd/compile/internal/typecheck/func.go | 49 |
1 files changed, 21 insertions, 28 deletions
diff --git a/src/cmd/compile/internal/typecheck/func.go b/src/cmd/compile/internal/typecheck/func.go index b3efb8f25a..e4c3088225 100644 --- a/src/cmd/compile/internal/typecheck/func.go +++ b/src/cmd/compile/internal/typecheck/func.go @@ -106,26 +106,7 @@ func PartialCallType(n *ir.SelectorExpr) *types.Type { // We use value capturing for values <= 128 bytes that are never reassigned // after capturing (effectively constant). func CaptureVars(fn *ir.Func) { - lno := base.Pos - base.Pos = fn.Pos() - cvars := fn.ClosureVars - out := cvars[:0] - for _, v := range cvars { - if v.Type() == nil { - // If v.Type is nil, it means v looked like it - // was going to be used in the closure, but - // isn't. This happens in struct literals like - // s{f: x} where we can't distinguish whether - // f is a field identifier or expression until - // resolving s. - continue - } - out = append(out, v) - - // type check closed variables outside the closure, - // so that the outer frame also grabs them and knows they escape. - Expr(v.Outer) - + for _, v := range fn.ClosureVars { outermost := v.Defn.(*ir.Name) // out parameters will be assigned to implicitly upon return. @@ -136,20 +117,13 @@ func CaptureVars(fn *ir.Func) { } if base.Flag.LowerM > 1 { - var name *types.Sym - if v.Curfn != nil && v.Curfn.Nname != nil { - name = v.Curfn.Sym() - } how := "ref" if v.Byval() { how = "value" } - base.WarnfAt(v.Pos(), "%v capturing by %s: %v (addr=%v assign=%v width=%d)", name, how, v.Sym(), outermost.Addrtaken(), outermost.Assigned(), v.Type().Size()) + base.WarnfAt(v.Pos(), "%v capturing by %s: %v (addr=%v assign=%v width=%d)", v.Curfn, how, v, outermost.Addrtaken(), outermost.Assigned(), v.Type().Size()) } } - - fn.ClosureVars = out - base.Pos = lno } // Lazy typechecking of imported bodies. For local functions, caninl will set ->typecheck @@ -396,6 +370,25 @@ func tcClosure(clo *ir.ClosureExpr, top int) { ir.CurFunc = oldfn } + out := 0 + for _, v := range fn.ClosureVars { + if v.Type() == nil { + // If v.Type is nil, it means v looked like it was going to be + // used in the closure, but isn't. This happens in struct + // literals like s{f: x} where we can't distinguish whether f is + // a field identifier or expression until resolving s. + continue + } + + // type check closed variables outside the closure, so that the + // outer frame also captures them. + Expr(v.Outer) + + fn.ClosureVars[out] = v + out++ + } + fn.ClosureVars = fn.ClosureVars[:out] + Target.Decls = append(Target.Decls, fn) } |