cmd/compile: combine ssa.html columns with identical contents

Combine columns in ssa.html output if they are identical. There
can now be multiple titles per column which are all clickable to
expand and collapse their column. Give collapsed columns some
padding for better readability. Some of the work in this CL was
started by Josh Bleecher Snyder and mailed to me in order to
continue to completion.

Updates #37766

Change-Id: I313b0917dc1bafe1eb99d91798ea915e5bcfaae9
Reviewed-on: https://go-review.googlesource.com/c/go/+/226209
Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/ssa/print.go b/src/cmd/compile/internal/ssa/print.go
index 58e4c3bbbe..36f09c3ad9 100644
--- a/src/cmd/compile/internal/ssa/print.go
+++ b/src/cmd/compile/internal/ssa/print.go
@@ -6,6 +6,7 @@ package ssa
 
 import (
 	"bytes"
+	"crypto/sha256"
 	"fmt"
 	"io"
 )
@@ -14,6 +15,13 @@ func printFunc(f *Func) {
 	f.Logf("%s", f)
 }
 
+func hashFunc(f *Func) []byte {
+	h := sha256.New()
+	p := stringFuncPrinter{w: h}
+	fprintFunc(p, f)
+	return h.Sum(nil)
+}
+
 func (f *Func) String() string {
 	var buf bytes.Buffer
 	p := stringFuncPrinter{w: &buf}