diff options
| author | Russ Cox <rsc@golang.org> | 2014-06-26 11:54:39 -0400 |
|---|---|---|
| committer | Russ Cox <rsc@golang.org> | 2014-06-26 11:54:39 -0400 |
| commit | 133cf52dde3138763a10d29f376f5fc353b6e99c (patch) | |
| tree | ff01fff7fd753e3208f025eea572bc904c516ef0 /src/liblink/asm5.c | |
| parent | dfa5443fe442274dc9ffd6b076e879040b3303e1 (diff) | |
| download | go-133cf52dde3138763a10d29f376f5fc353b6e99c.tar.gz | |
all: remove 'extern register M *m' from runtime
The runtime has historically held two dedicated values g (current goroutine)
and m (current thread) in 'extern register' slots (TLS on x86, real registers
backed by TLS on ARM).
This CL removes the extern register m; code now uses g->m.
On ARM, this frees up the register that formerly held m (R9).
This is important for NaCl, because NaCl ARM code cannot use R9 at all.
The Go 1 macrobenchmarks (those with per-op times >= 10 ?s) are unaffected:
BenchmarkBinaryTree17 5491374955 5471024381 -0.37%
BenchmarkFannkuch11 4357101311 4275174828 -1.88%
BenchmarkGobDecode 11029957 11364184 +3.03%
BenchmarkGobEncode 6852205 6784822 -0.98%
BenchmarkGzip 650795967 650152275 -0.10%
BenchmarkGunzip 140962363 141041670 +0.06%
BenchmarkHTTPClientServer 71581 73081 +2.10%
BenchmarkJSONEncode 31928079 31913356 -0.05%
BenchmarkJSONDecode 117470065 113689916 -3.22%
BenchmarkMandelbrot200 6008923 5998712 -0.17%
BenchmarkGoParse 6310917 6327487 +0.26%
BenchmarkRegexpMatchMedium_1K 114568 114763 +0.17%
BenchmarkRegexpMatchHard_1K 168977 169244 +0.16%
BenchmarkRevcomp 935294971 914060918 -2.27%
BenchmarkTemplate 145917123 148186096 +1.55%
Minux previous reported larger variations, but these were caused by
run-to-run noise, not repeatable slowdowns.
Actual code changes by Minux.
I only did the docs and the benchmarking.
LGTM=dvyukov, iant, minux
R=minux, josharian, iant, dave, bradfitz, dvyukov
CC=golang-codereviews
https://codereview.appspot.com/109050043
Diffstat (limited to 'src/liblink/asm5.c')
| -rw-r--r-- | src/liblink/asm5.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/src/liblink/asm5.c b/src/liblink/asm5.c index 465b645b2..2d084801f 100644 --- a/src/liblink/asm5.c +++ b/src/liblink/asm5.c @@ -572,8 +572,8 @@ span5(Link *ctxt, LSym *cursym) * code references to be relocated too, and then * perhaps we'd be able to parallelize the span loop above. */ - if(ctxt->gmsym == nil) - ctxt->gmsym = linklookup(ctxt, "runtime.tlsgm", 0); + if(ctxt->tlsg == nil) + ctxt->tlsg = linklookup(ctxt, "runtime.tlsg", 0); p = cursym->text; ctxt->autosize = p->to.offset + 4; @@ -1377,11 +1377,11 @@ if(0 /*debug['G']*/) print("%ux: %s: arm %d\n", (uint32)(p->pc), p->from.sym->na rel->sym = p->to.sym; rel->add = p->to.offset; - // runtime.tlsgm (aka gmsym) is special. + // runtime.tlsg is special. // Its "address" is the offset from the TLS thread pointer // to the thread-local g and m pointers. // Emit a TLS relocation instead of a standard one. - if(rel->sym == ctxt->gmsym) { + if(rel->sym == ctxt->tlsg) { rel->type = R_TLS; if(ctxt->flag_shared) rel->add += ctxt->pc - p->pcrel->pc - 8 - rel->siz; |