cmd/gc: bypass DATA instruction for data initialized to integer constant

Eventually we will want to bypass DATA for everything,
but the relocations are not standardized well enough across
architectures to make that possible.

This did not help as much as I expected, but it is definitely better.
It shaves maybe 1-2% off all.bash depending on how much you
trust the timings of a single run:

Before: 241.139r 362.702u 112.967s
After:  234.339r 359.623u 111.045s

R=golang-codereviews, gobot, r, iant
CC=golang-codereviews
https://golang.org/cl/44650043

diff --git a/src/cmd/5g/gobj.c b/src/cmd/5g/gobj.c
index eaa28c111367b0765510f04f71ec9f00d08d1f0b..5e988878f7d58e4efe8f078fdbfea9be41501291 100644 (file)
--- a/src/cmd/5g/gobj.c
+++ b/src/cmd/5g/gobj.c
@@ -223,27 +223,6 @@ dgostringptr(Sym *s, int off, char *str)
        return dgostrlitptr(s, off, lit);
 }
 
-int
-duintxx(Sym *s, int off, uint64 v, int wid)
-{
-       Prog *p;
-
-       off = rnd(off, wid);
-
-       p = gins(ADATA, N, N);
-       p->from.type = D_OREG;
-       p->from.name = D_EXTERN;
-       p->from.sym = linksym(s);
-       p->from.offset = off;
-       p->reg = wid;
-       p->to.type = D_CONST;
-       p->to.name = D_NONE;
-       p->to.offset = v;
-       off += wid;
-
-       return off;
-}
-
 int
 dsymptr(Sym *s, int off, Sym *x, int xoff)
 {

diff --git a/src/cmd/6g/gobj.c b/src/cmd/6g/gobj.c
index e22defe4f1e9d42f7f4821b8f71b296228f19618..04e837b1384ac59105d6aece7123a0ca89f22529 100644 (file)
--- a/src/cmd/6g/gobj.c
+++ b/src/cmd/6g/gobj.c
@@ -205,27 +205,6 @@ dgostringptr(Sym *s, int off, char *str)
        return dgostrlitptr(s, off, lit);
 }
 
-int
-duintxx(Sym *s, int off, uint64 v, int wid)
-{
-       Prog *p;
-
-       off = rnd(off, wid);
-
-       p = gins(ADATA, N, N);
-       p->from.type = D_EXTERN;
-       p->from.index = D_NONE;
-       p->from.sym = linksym(s);
-       p->from.offset = off;
-       p->from.scale = wid;
-       p->to.type = D_CONST;
-       p->to.index = D_NONE;
-       p->to.offset = v;
-       off += wid;
-
-       return off;
-}
-
 int
 dsymptr(Sym *s, int off, Sym *x, int xoff)
 {

diff --git a/src/cmd/8g/gobj.c b/src/cmd/8g/gobj.c
index 68846ef2198399dc8d6d36ea429296253205c2ce..fa0605e6c763522f18b0feefb432799f709d1908 100644 (file)
--- a/src/cmd/8g/gobj.c
+++ b/src/cmd/8g/gobj.c
@@ -216,28 +216,6 @@ dgostringptr(Sym *s, int off, char *str)
        return dgostrlitptr(s, off, lit);
 }
 
-
-int
-duintxx(Sym *s, int off, uint64 v, int wid)
-{
-       Prog *p;
-
-       off = rnd(off, wid);
-
-       p = gins(ADATA, N, N);
-       p->from.type = D_EXTERN;
-       p->from.index = D_NONE;
-       p->from.sym = linksym(s);
-       p->from.offset = off;
-       p->from.scale = wid;
-       p->to.type = D_CONST;
-       p->to.index = D_NONE;
-       p->to.offset = v;
-       off += wid;
-
-       return off;
-}
-
 int
 dsymptr(Sym *s, int off, Sym *x, int xoff)
 {

diff --git a/src/cmd/gc/obj.c b/src/cmd/gc/obj.c
index 3b9a97320f845b7d1123fab615a9c7559ff41d05..c17be5c39812296735664a9633b370a25ee5b7fa 100644 (file)
--- a/src/cmd/gc/obj.c
+++ b/src/cmd/gc/obj.c
@@ -160,6 +160,16 @@ linksym(Sym *s)
        return s->lsym; 
 }
 
+int
+duintxx(Sym *s, int off, uint64 v, int wid)
+{
+       // Update symbol data directly instead of generating a
+       // DATA instruction that liblink will have to interpret later.
+       // This reduces compilation time and memory usage.
+       off = rnd(off, wid);
+       return setuintxx(ctxt, linksym(s), off, v, wid);
+}
+
 int
 duint8(Sym *s, int off, uint8 v)
 {