go/ssa: Move BasicBlock operations into block.go
Move the BasicBlock related functions and methods into their own file.
Miscellaneous cleanup.
Updates golang/go#48525
Change-Id: If1c89cf53a4dba25d0c8b703e53c79eb27957f9c
Reviewed-on: https://go-review.googlesource.com/c/tools/+/386316
Reviewed-by: Zvonimir Pavlinovic <zpavlinovic@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
Trust: Tim King <taking@google.com>
Run-TryBot: Tim King <taking@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
diff --git a/go/ssa/block.go b/go/ssa/block.go
new file mode 100644
index 0000000..35f3173
--- /dev/null
+++ b/go/ssa/block.go
@@ -0,0 +1,118 @@
+// Copyright 2022 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 "fmt"
+
+// This file implements the BasicBlock type.
+
+// addEdge adds a control-flow graph edge from from to to.
+func addEdge(from, to *BasicBlock) {
+ from.Succs = append(from.Succs, to)
+ to.Preds = append(to.Preds, from)
+}
+
+// Parent returns the function that contains block b.
+func (b *BasicBlock) Parent() *Function { return b.parent }
+
+// String returns a human-readable label of this block.
+// It is not guaranteed unique within the function.
+//
+func (b *BasicBlock) String() string {
+ return fmt.Sprintf("%d", b.Index)
+}
+
+// emit appends an instruction to the current basic block.
+// If the instruction defines a Value, it is returned.
+//
+func (b *BasicBlock) emit(i Instruction) Value {
+ i.setBlock(b)
+ b.Instrs = append(b.Instrs, i)
+ v, _ := i.(Value)
+ return v
+}
+
+// predIndex returns the i such that b.Preds[i] == c or panics if
+// there is none.
+func (b *BasicBlock) predIndex(c *BasicBlock) int {
+ for i, pred := range b.Preds {
+ if pred == c {
+ return i
+ }
+ }
+ panic(fmt.Sprintf("no edge %s -> %s", c, b))
+}
+
+// hasPhi returns true if b.Instrs contains φ-nodes.
+func (b *BasicBlock) hasPhi() bool {
+ _, ok := b.Instrs[0].(*Phi)
+ return ok
+}
+
+// phis returns the prefix of b.Instrs containing all the block's φ-nodes.
+func (b *BasicBlock) phis() []Instruction {
+ for i, instr := range b.Instrs {
+ if _, ok := instr.(*Phi); !ok {
+ return b.Instrs[:i]
+ }
+ }
+ return nil // unreachable in well-formed blocks
+}
+
+// replacePred replaces all occurrences of p in b's predecessor list with q.
+// Ordinarily there should be at most one.
+//
+func (b *BasicBlock) replacePred(p, q *BasicBlock) {
+ for i, pred := range b.Preds {
+ if pred == p {
+ b.Preds[i] = q
+ }
+ }
+}
+
+// replaceSucc replaces all occurrences of p in b's successor list with q.
+// Ordinarily there should be at most one.
+//
+func (b *BasicBlock) replaceSucc(p, q *BasicBlock) {
+ for i, succ := range b.Succs {
+ if succ == p {
+ b.Succs[i] = q
+ }
+ }
+}
+
+// removePred removes all occurrences of p in b's
+// predecessor list and φ-nodes.
+// Ordinarily there should be at most one.
+//
+func (b *BasicBlock) removePred(p *BasicBlock) {
+ phis := b.phis()
+
+ // We must preserve edge order for φ-nodes.
+ j := 0
+ for i, pred := range b.Preds {
+ if pred != p {
+ b.Preds[j] = b.Preds[i]
+ // Strike out φ-edge too.
+ for _, instr := range phis {
+ phi := instr.(*Phi)
+ phi.Edges[j] = phi.Edges[i]
+ }
+ j++
+ }
+ }
+ // Nil out b.Preds[j:] and φ-edges[j:] to aid GC.
+ for i := j; i < len(b.Preds); i++ {
+ b.Preds[i] = nil
+ for _, instr := range phis {
+ instr.(*Phi).Edges[i] = nil
+ }
+ }
+ b.Preds = b.Preds[:j]
+ for _, instr := range phis {
+ phi := instr.(*Phi)
+ phi.Edges = phi.Edges[:j]
+ }
+}
diff --git a/go/ssa/func.go b/go/ssa/func.go
index 0b99bc9..d599da5 100644
--- a/go/ssa/func.go
+++ b/go/ssa/func.go
@@ -4,7 +4,7 @@
package ssa
-// This file implements the Function and BasicBlock types.
+// This file implements the Function type.
import (
"bytes"
@@ -17,115 +17,6 @@
"strings"
)
-// addEdge adds a control-flow graph edge from from to to.
-func addEdge(from, to *BasicBlock) {
- from.Succs = append(from.Succs, to)
- to.Preds = append(to.Preds, from)
-}
-
-// Parent returns the function that contains block b.
-func (b *BasicBlock) Parent() *Function { return b.parent }
-
-// String returns a human-readable label of this block.
-// It is not guaranteed unique within the function.
-//
-func (b *BasicBlock) String() string {
- return fmt.Sprintf("%d", b.Index)
-}
-
-// emit appends an instruction to the current basic block.
-// If the instruction defines a Value, it is returned.
-//
-func (b *BasicBlock) emit(i Instruction) Value {
- i.setBlock(b)
- b.Instrs = append(b.Instrs, i)
- v, _ := i.(Value)
- return v
-}
-
-// predIndex returns the i such that b.Preds[i] == c or panics if
-// there is none.
-func (b *BasicBlock) predIndex(c *BasicBlock) int {
- for i, pred := range b.Preds {
- if pred == c {
- return i
- }
- }
- panic(fmt.Sprintf("no edge %s -> %s", c, b))
-}
-
-// hasPhi returns true if b.Instrs contains φ-nodes.
-func (b *BasicBlock) hasPhi() bool {
- _, ok := b.Instrs[0].(*Phi)
- return ok
-}
-
-// phis returns the prefix of b.Instrs containing all the block's φ-nodes.
-func (b *BasicBlock) phis() []Instruction {
- for i, instr := range b.Instrs {
- if _, ok := instr.(*Phi); !ok {
- return b.Instrs[:i]
- }
- }
- return nil // unreachable in well-formed blocks
-}
-
-// replacePred replaces all occurrences of p in b's predecessor list with q.
-// Ordinarily there should be at most one.
-//
-func (b *BasicBlock) replacePred(p, q *BasicBlock) {
- for i, pred := range b.Preds {
- if pred == p {
- b.Preds[i] = q
- }
- }
-}
-
-// replaceSucc replaces all occurrences of p in b's successor list with q.
-// Ordinarily there should be at most one.
-//
-func (b *BasicBlock) replaceSucc(p, q *BasicBlock) {
- for i, succ := range b.Succs {
- if succ == p {
- b.Succs[i] = q
- }
- }
-}
-
-// removePred removes all occurrences of p in b's
-// predecessor list and φ-nodes.
-// Ordinarily there should be at most one.
-//
-func (b *BasicBlock) removePred(p *BasicBlock) {
- phis := b.phis()
-
- // We must preserve edge order for φ-nodes.
- j := 0
- for i, pred := range b.Preds {
- if pred != p {
- b.Preds[j] = b.Preds[i]
- // Strike out φ-edge too.
- for _, instr := range phis {
- phi := instr.(*Phi)
- phi.Edges[j] = phi.Edges[i]
- }
- j++
- }
- }
- // Nil out b.Preds[j:] and φ-edges[j:] to aid GC.
- for i := j; i < len(b.Preds); i++ {
- b.Preds[i] = nil
- for _, instr := range phis {
- instr.(*Phi).Edges[i] = nil
- }
- }
- b.Preds = b.Preds[:j]
- for _, instr := range phis {
- phi := instr.(*Phi)
- phi.Edges = phi.Edges[:j]
- }
-}
-
// Destinations associated with unlabelled for/switch/select stmts.
// We push/pop one of these as we enter/leave each construct and for
// each BranchStmt we scan for the innermost target of the right type.
