1 files changed, 62 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/cache.go b/src/cmd/compile/internal/ssa/cache.go
new file mode 100644
index 0000000..ba36edd
--- /dev/null
+++ b/src/cmd/compile/internal/ssa/cache.go
@@ -0,0 +1,62 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ssa
+
+import (
+	"cmd/internal/obj"
+	"sort"
+)
+
+// A Cache holds reusable compiler state.
+// It is intended to be re-used for multiple Func compilations.
+type Cache struct {
+	// Storage for low-numbered values and blocks.
+	values [2000]Value
+	blocks [200]Block
+	locs   [2000]Location
+
+	// Reusable stackAllocState.
+	// See stackalloc.go's {new,put}StackAllocState.
+	stackAllocState *stackAllocState
+
+	scrPoset []*poset // scratch poset to be reused
+
+	// Reusable regalloc state.
+	regallocValues []valState
+
+	ValueToProgAfter []*obj.Prog
+	debugState       debugState
+
+	Liveness interface{} // *gc.livenessFuncCache
+
+	// Free "headers" for use by the allocators in allocators.go.
+	// Used to put slices in sync.Pools without allocation.
+	hdrValueSlice []*[]*Value
+	hdrInt64Slice []*[]int64
+}
+
+func (c *Cache) Reset() {
+	nv := sort.Search(len(c.values), func(i int) bool { return c.values[i].ID == 0 })
+	xv := c.values[:nv]
+	for i := range xv {
+		xv[i] = Value{}
+	}
+	nb := sort.Search(len(c.blocks), func(i int) bool { return c.blocks[i].ID == 0 })
+	xb := c.blocks[:nb]
+	for i := range xb {
+		xb[i] = Block{}
+	}
+	nl := sort.Search(len(c.locs), func(i int) bool { return c.locs[i] == nil })
+	xl := c.locs[:nl]
+	for i := range xl {
+		xl[i] = nil
+	}
+
+	// regalloc sets the length of c.regallocValues to whatever it may use,
+	// so clear according to length.
+	for i := range c.regallocValues {
+		c.regallocValues[i] = valState{}
+	}
+}