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cmd/link: stop generating garbage in elfhash

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All callers already had strings. No need to generate byte slice copies
to work on bytes.

Performance not measured, but probably helps at least a bit.

Change-Id: Iec3230b69724fac68caae7aad46f2ce1504e82e5
Reviewed-on: https://go-review.googlesource.com/20136
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
This commit is contained in:
Brad Fitzpatrick 2016-03-02 14:29:44 -08:00
parent 03f3bfc460
commit d7cdf66978
1 changed files with 7 additions and 11 deletions
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18
src/cmd/link/internal/ld/elf.go
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@ -1042,19 +1042,15 @@ func elfwritehdr() uint32 {
} }
/* Taken directly from the definition document for ELF64 */ /* Taken directly from the definition document for ELF64 */
func elfhash(name []byte) uint32 { func elfhash(name string) uint32 {
var h uint32 = 0 var h uint32
var g uint32 for i := 0; i < len(name); i++ {
for len(name) != 0 { h = (h << 4) + uint32(name[i])
h = (h << 4) + uint32(name[0]) if g := h & 0xf0000000; g != 0 {
name = name[1:]
g = h & 0xf0000000
if g != 0 {
h ^= g >> 24 h ^= g >> 24
} }
h &= 0x0fffffff h &= 0x0fffffff
} }
return h return h
} }
@ -1371,7 +1367,7 @@ func elfdynhash() {
} }
name := sy.Extname name := sy.Extname
hc := elfhash([]byte(name)) hc := elfhash(name)
b = int(hc % uint32(nbucket)) b = int(hc % uint32(nbucket))
chain[sy.Dynid] = buckets[b] chain[sy.Dynid] = buckets[b]
@ -1418,7 +1414,7 @@ func elfdynhash() {
i++ i++
// aux struct // aux struct
Adduint32(Ctxt, s, elfhash([]byte(x.vers))) // hash Adduint32(Ctxt, s, elfhash(x.vers)) // hash
Adduint16(Ctxt, s, 0) // flags Adduint16(Ctxt, s, 0) // flags
Adduint16(Ctxt, s, uint16(x.num)) // other - index we refer to this by Adduint16(Ctxt, s, uint16(x.num)) // other - index we refer to this by
Adduint32(Ctxt, s, uint32(Addstring(dynstr, x.vers))) // version string offset Adduint32(Ctxt, s, uint32(Addstring(dynstr, x.vers))) // version string offset