[dev.regabi] cmd/compile: add Linksym helpers

Syms are meant to be just interned (pkg, name) tuples, and are a
purely abstract, Go-language concept. As such, associating them with
linker symbols (a low-level, implementation-oriented detail) is
inappropriate.

There's still work to be done before linker symbols can be directly
attached to their appropriate, higher-level objects instead. But in
the mean-time, we can at least add helper functions and discourage
folks from using Sym.Linksym directly. The next CL will mechanically
rewrite code to use these helpers where possible.

Passes toolstash -cmp.

Change-Id: I413bd1c80bce056304f9a7343526bd153f2b9c7d
Reviewed-on: https://go-review.googlesource.com/c/go/+/280639
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>

1 files changed, 4 insertions, 10 deletions

diff --git a/src/cmd/compile/internal/ssagen/pgen.go b/src/cmd/compile/internal/ssagen/pgen.go
index bc6be20d868..72ce233fdad 100644
--- a/src/cmd/compile/internal/ssagen/pgen.go
+++ b/src/cmd/compile/internal/ssagen/pgen.go
@@ -225,7 +225,7 @@ func StackOffset(slot ssa.LocalSlot) int32 {
 
 // fieldtrack adds R_USEFIELD relocations to fnsym to record any
 // struct fields that it used.
-func fieldtrack(fnsym *obj.LSym, tracked map[*types.Sym]struct{}) {
+func fieldtrack(fnsym *obj.LSym, tracked map[*obj.LSym]struct{}) {
 	if fnsym == nil {
 		return
 	}
@@ -233,24 +233,18 @@ func fieldtrack(fnsym *obj.LSym, tracked map[*types.Sym]struct{}) {
 		return
 	}
 
-	trackSyms := make([]*types.Sym, 0, len(tracked))
+	trackSyms := make([]*obj.LSym, 0, len(tracked))
 	for sym := range tracked {
 		trackSyms = append(trackSyms, sym)
 	}
-	sort.Sort(symByName(trackSyms))
+	sort.Slice(trackSyms, func(i, j int) bool { return trackSyms[i].Name < trackSyms[j].Name })
 	for _, sym := range trackSyms {
 		r := obj.Addrel(fnsym)
-		r.Sym = sym.Linksym()
+		r.Sym = sym
 		r.Type = objabi.R_USEFIELD
 	}
 }
 
-type symByName []*types.Sym
-
-func (a symByName) Len() int           { return len(a) }
-func (a symByName) Less(i, j int) bool { return a[i].Name < a[j].Name }
-func (a symByName) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
-
 // largeStack is info about a function whose stack frame is too large (rare).
 type largeStack struct {
 	locals int64