qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-10-05 20:31:20 -06:00
Code Releases Activity

[dev.ssa] cmd/compile: fix stackalloc handling of zero-aligned variables

Browse Source 
Prior to this fix, a zero-aligned variable such as a flags
variable would reset n to 0.

While we're here, log the stack layout so that debugging
and reading the generated assembly is easier.

Change-Id: I18ef83ea95b6ea877c83f2e595e14c48c9ad7d84
Reviewed-on: https://go-review.googlesource.com/12439
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Josh Bleecher Snyder 2015-07-20 15:24:51 -07:00
parent 26f135d7c1
commit 67bfd69564
1 changed files with 8 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/cmd/compile/internal/ssa/stackalloc.go
View File

@ -20,6 +20,7 @@ func stackalloc(f *Func) {
n = v.AuxInt
}
}
f.Logf("stackalloc: 0-%d for callee arguments/returns\n", n)
// TODO: group variables by ptr/nonptr, size, etc. Emit ptr vars last
// so stackmap is smaller.
@ -36,6 +37,7 @@ func stackalloc(f *Func) {
continue
}
n = align(n, v.Type.Alignment())
f.Logf("stackalloc: %d-%d for %v\n", n, n+v.Type.Size(), v)
loc := &LocalSlot{n}
n += v.Type.Size()
home = setloc(home, v, loc)
@ -62,6 +64,7 @@ func stackalloc(f *Func) {
continue
}
n = align(n, v.Type.Alignment())
f.Logf("stackalloc: %d-%d for %v\n", n, n+v.Type.Size(), v)
loc := &LocalSlot{n}
n += v.Type.Size()
home = setloc(home, v, loc)
@ -77,12 +80,14 @@ func stackalloc(f *Func) {
}
t := s.Typ
n = align(n, t.Alignment())
f.Logf("stackalloc: %d-%d for auto %v\n", n, n+t.Size(), v)
s.Offset = n
n += t.Size()
}
}
n = align(n, f.Config.PtrSize)
f.Logf("stackalloc: %d-%d for return address\n", n, n+f.Config.ptrSize)
n += f.Config.PtrSize // space for return address. TODO: arch-dependent
f.RegAlloc = home
f.FrameSize = n
@ -92,5 +97,8 @@ func stackalloc(f *Func) {
// align increases n to the next multiple of a. a must be a power of 2.
func align(n int64, a int64) int64 {
if a == 0 {
return n
}
return (n + a - 1) &^ (a - 1)
}