qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-11-19 23:04:40 -07:00
Code Releases Activity

runtime: avoid allocation for make([]T, 0)

Browse Source 
R=gri, iant, iant
CC=golang-dev
https://golang.org/cl/5375093
This commit is contained in:
Russ Cox 2011-11-15 12:05:25 -05:00
parent 276473cd72
commit 94c2536e3f
1 changed files with 8 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
src/pkg/runtime/slice.c
View File

@ -32,6 +32,11 @@ runtime·makeslice(SliceType *t, int64 len, int64 cap, Slice ret)
}
}
// Dummy word to use as base pointer for make([]T, 0).
// Since you cannot take the address of such a slice,
// you can't tell that they all have the same base pointer.
static uintptr zerobase;
static void
makeslice1(SliceType *t, int32 len, int32 cap, Slice *ret)
{
@ -42,7 +47,9 @@ makeslice1(SliceType *t, int32 len, int32 cap, Slice *ret)
ret->len = len;
ret->cap = cap;
if((t->elem->kind&KindNoPointers))
if(cap == 0)
ret->array = (byte*)&zerobase;
else if((t->elem->kind&KindNoPointers))
ret->array = runtime·mallocgc(size, FlagNoPointers, 1, 1);
else
ret->array = runtime·mal(size);