From fc479468e896f58dfc096bd534a19785cfff3a96 Mon Sep 17 00:00:00 2001 From: Tim King Date: Wed, 16 Feb 2022 13:23:14 -0800 Subject: [PATCH] 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 Reviewed-by: Robert Findley Trust: Tim King Run-TryBot: Tim King gopls-CI: kokoro TryBot-Result: Gopher Robot --- go/ssa/block.go | 118 ++++++++++++++++++++++++++++++++++++++++++++++++ go/ssa/func.go | 111 +-------------------------------------------- 2 files changed, 119 insertions(+), 110 deletions(-) create mode 100644 go/ssa/block.go diff --git a/go/ssa/block.go b/go/ssa/block.go new file mode 100644 index 0000000000..35f317332d --- /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 0b99bc9ba1..d599da5c3e 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 @@ import ( "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.