cmd/compile: move Type.Maplineno to separate data structure

Relatively few types are ever used as map keys,
so tracking this separately is a net win.

Passes toolstash -cmp.

name       old alloc/op     new alloc/op     delta
Template       55.9MB ± 0%      55.5MB ± 0%  -0.71%        (p=0.000 n=10+10)
Unicode        37.8MB ± 0%      37.7MB ± 0%  -0.27%        (p=0.000 n=10+10)
GoTypes         180MB ± 0%       179MB ± 0%  -0.52%         (p=0.000 n=7+10)
Compiler        806MB ± 0%       803MB ± 0%  -0.41%        (p=0.000 n=10+10)

CPU and number of allocs are unchanged.

Change-Id: I6d60d74a4866995a231dfed3dd5792d75d904292
Reviewed-on: https://go-review.googlesource.com/21622
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

diff --git a/src/cmd/compile/internal/gc/sizeof_test.go b/src/cmd/compile/internal/gc/sizeof_test.go
index 8b0dfe538eb78a79190c8dfa794ae902414edef3..f2b1461bc80454202035a075f16f061fc8af73cc 100644 (file)
--- a/src/cmd/compile/internal/gc/sizeof_test.go
+++ b/src/cmd/compile/internal/gc/sizeof_test.go
@@ -27,7 +27,7 @@ func TestSizeof(t *testing.T) {
                {Name{}, 52, 80},
                {Node{}, 92, 144},
                {Sym{}, 60, 112},
-               {Type{}, 56, 88},
+               {Type{}, 52, 80},
                {MapType{}, 20, 40},
                {ForwardType{}, 16, 32},
                {FuncType{}, 28, 48},

diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index a61b8bcd271f0719820da15e5287f2f2e947e395..035bd815c2f999aaa294f106f59e345f509da650 100644 (file)
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -390,8 +390,8 @@ func checkMapKeyType(key *Type) {
                // before key is fully defined, the error
                // will only be printed for the first one.
                // good enough.
-               if key.Maplineno == 0 {
-                       key.Maplineno = lineno
+               if maplineno[key] == 0 {
+                       maplineno[key] = lineno
                }
        }
 }

diff --git a/src/cmd/compile/internal/gc/type.go b/src/cmd/compile/internal/gc/type.go
index 3d2f01ef7d9008ab9cc481a5eaa6784054cdaf9d..eee8e0384ad733d27255fcd56f70fb25f2cfbed1 100644 (file)
--- a/src/cmd/compile/internal/gc/type.go
+++ b/src/cmd/compile/internal/gc/type.go
@@ -153,8 +153,6 @@ type Type struct {
        Vargen int32 // unique name for OTYPE/ONAME
        Lineno int32 // line at which this type was declared, implicitly or explicitly
 
-       Maplineno int32 // first use of this type as a map key
-
        Etype      EType // kind of type
        Noalg      bool  // suppress hash and eq algorithm generation
        Trecur     uint8 // to detect loops

diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index ab7d257aacc822235b10a2f011799ea5415b5962..a20f87d940d796291a9af0a75e7bc3b48378259a 100644 (file)
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -3513,7 +3513,11 @@ func domethod(n *Node) {
        checkwidth(n.Type)
 }
 
-var mapqueue []*Node
+var (
+       mapqueue []*Node
+       // maplineno tracks the line numbers at which types are first used as map keys
+       maplineno = map[*Type]int32{}
+)
 
 func copytype(n *Node, t *Type) {
        if t.Etype == TFORW {
@@ -3522,7 +3526,7 @@ func copytype(n *Node, t *Type) {
                return
        }
 
-       maplineno := n.Type.Maplineno
+       mapline := maplineno[n.Type]
        embedlineno := n.Type.ForwardType().Embedlineno
        l := n.Type.ForwardType().Copyto
 
@@ -3559,8 +3563,8 @@ func copytype(n *Node, t *Type) {
        lineno = lno
 
        // Queue check for map until all the types are done settling.
-       if maplineno != 0 {
-               t.Maplineno = maplineno
+       if mapline != 0 {
+               maplineno[t] = mapline
                mapqueue = append(mapqueue, n)
        }
 }
@@ -3609,7 +3613,7 @@ ret:
                }
 
                for _, n := range mapqueue {
-                       lineno = n.Type.Maplineno
+                       lineno = maplineno[n.Type]
                        checkMapKeyType(n.Type)
                }