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Code Releases Activity

cmd/internal/obj: clean up brloop

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Add docs.
Reduce indentation.

Passes toolstash-check -all.

Change-Id: I968d1af25989886ae9945052e05e211a107dde9c
Reviewed-on: https://go-review.googlesource.com/38443
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This commit is contained in:
Josh Bleecher Snyder 2017-03-21 22:06:39 -07:00
parent 4c8023bfed
commit 2f2cd557a6
1 changed files with 19 additions and 17 deletions
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36
src/cmd/internal/obj/pass.go
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@ -32,21 +32,21 @@ package obj
// Code and data passes. // Code and data passes.
func brloop(ctxt *Link, p *Prog) *Prog { // brloop returns the ultimate destination of the series of unconditional jumps beginning at p.
var q *Prog // In the case of an infinite loop, brloop returns nil.
func brloop(p *Prog) *Prog {
c := 0 c := 0
for q = p; q != nil; q = q.Pcond { for q := p; q != nil; q = q.Pcond {
if q.As != AJMP || q.Pcond == nil { if q.As != AJMP || q.Pcond == nil {
break return q
} }
c++ c++
if c >= 5000 { if c >= 5000 {
// infinite loop
return nil return nil
} }
} }
panic("unreachable")
return q
} }
// checkaddr checks that a has an expected encoding, especially TYPE_CONST vs TYPE_ADDR. // checkaddr checks that a has an expected encoding, especially TYPE_CONST vs TYPE_ADDR.
@ -169,16 +169,18 @@ func linkpatch(ctxt *Link, sym *LSym) {
p.Pcond = q p.Pcond = q
} }
if ctxt.Flag_optimize { if !ctxt.Flag_optimize {
for p := sym.Text; p != nil; p = p.Link { return
if p.Pcond != nil { }
p.Pcond = brloop(ctxt, p.Pcond)
if p.Pcond != nil { // Collapse series of jumps to jumps.
if p.To.Type == TYPE_BRANCH { for p := sym.Text; p != nil; p = p.Link {
p.To.Offset = p.Pcond.Pc if p.Pcond == nil {
} continue
} }
} p.Pcond = brloop(p.Pcond)
if p.Pcond != nil && p.To.Type == TYPE_BRANCH {
p.To.Offset = p.Pcond.Pc
} }
} }
} }