cmd/link: clean up per-binary slice creation in ld

A code cleanup opportunity noticed while trying to make slices
be aligned.

Change-Id: I34a807b4cf67d9b4a136c83714a34ffe71dcb166
Reviewed-on: https://go-review.googlesource.com/c/go/+/462757
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

diff --git a/src/cmd/link/internal/ld/symtab.go b/src/cmd/link/internal/ld/symtab.go
index 5f5f2e1d0ba38e946a181f585612f136d88e3e25..6faa8819dd495680343a23aaafc8ba857df15050 100644 (file)
--- a/src/cmd/link/internal/ld/symtab.go
+++ b/src/cmd/link/internal/ld/symtab.go
@@ -632,32 +632,44 @@ func (ctxt *Link) symtab(pcln *pclntab) []sym.SymKind {
        // the definition of moduledata in runtime/symtab.go.
        // This code uses several global variables that are set by pcln.go:pclntab.
        moduledata := ldr.MakeSymbolUpdater(ctxt.Moduledata)
+
+       slice := func(sym loader.Sym, len uint64) {
+               moduledata.AddAddr(ctxt.Arch, sym)
+               moduledata.AddUint(ctxt.Arch, len)
+               moduledata.AddUint(ctxt.Arch, len)
+       }
+
+       sliceSym := func(sym loader.Sym) {
+               slice(sym, uint64(ldr.SymSize(sym)))
+       }
+
+       nilSlice := func() {
+               moduledata.AddUint(ctxt.Arch, 0)
+               moduledata.AddUint(ctxt.Arch, 0)
+               moduledata.AddUint(ctxt.Arch, 0)
+       }
+
        // The pcHeader
        moduledata.AddAddr(ctxt.Arch, pcln.pcheader)
+
        // The function name slice
-       moduledata.AddAddr(ctxt.Arch, pcln.funcnametab)
-       moduledata.AddUint(ctxt.Arch, uint64(ldr.SymSize(pcln.funcnametab)))
-       moduledata.AddUint(ctxt.Arch, uint64(ldr.SymSize(pcln.funcnametab)))
+       sliceSym(pcln.funcnametab)
+
        // The cutab slice
-       moduledata.AddAddr(ctxt.Arch, pcln.cutab)
-       moduledata.AddUint(ctxt.Arch, uint64(ldr.SymSize(pcln.cutab)))
-       moduledata.AddUint(ctxt.Arch, uint64(ldr.SymSize(pcln.cutab)))
+       sliceSym(pcln.cutab)
+
        // The filetab slice
-       moduledata.AddAddr(ctxt.Arch, pcln.filetab)
-       moduledata.AddUint(ctxt.Arch, uint64(ldr.SymSize(pcln.filetab)))
-       moduledata.AddUint(ctxt.Arch, uint64(ldr.SymSize(pcln.filetab)))
+       sliceSym(pcln.filetab)
+
        // The pctab slice
-       moduledata.AddAddr(ctxt.Arch, pcln.pctab)
-       moduledata.AddUint(ctxt.Arch, uint64(ldr.SymSize(pcln.pctab)))
-       moduledata.AddUint(ctxt.Arch, uint64(ldr.SymSize(pcln.pctab)))
+       sliceSym(pcln.pctab)
+
        // The pclntab slice
-       moduledata.AddAddr(ctxt.Arch, pcln.pclntab)
-       moduledata.AddUint(ctxt.Arch, uint64(ldr.SymSize(pcln.pclntab)))
-       moduledata.AddUint(ctxt.Arch, uint64(ldr.SymSize(pcln.pclntab)))
+       slice(pcln.pclntab, uint64(ldr.SymSize(pcln.pclntab)))
+
        // The ftab slice
-       moduledata.AddAddr(ctxt.Arch, pcln.pclntab)
-       moduledata.AddUint(ctxt.Arch, uint64(pcln.nfunc+1))
-       moduledata.AddUint(ctxt.Arch, uint64(pcln.nfunc+1))
+       slice(pcln.pclntab, uint64(pcln.nfunc+1))
+
        // findfunctab
        moduledata.AddAddr(ctxt.Arch, pcln.findfunctab)
        // minpc, maxpc
@@ -708,22 +720,18 @@ func (ctxt *Link) symtab(pcln *pclntab) []sym.SymKind {
        }
 
        // text section information
-       moduledata.AddAddr(ctxt.Arch, textsectionmapSym)
-       moduledata.AddUint(ctxt.Arch, uint64(nsections))
-       moduledata.AddUint(ctxt.Arch, uint64(nsections))
+       slice(textsectionmapSym, uint64(nsections))
 
        // The typelinks slice
        typelinkSym := ldr.Lookup("runtime.typelink", 0)
        ntypelinks := uint64(ldr.SymSize(typelinkSym)) / 4
-       moduledata.AddAddr(ctxt.Arch, typelinkSym)
-       moduledata.AddUint(ctxt.Arch, ntypelinks)
-       moduledata.AddUint(ctxt.Arch, ntypelinks)
+       slice(typelinkSym, ntypelinks)
+
        // The itablinks slice
        itablinkSym := ldr.Lookup("runtime.itablink", 0)
        nitablinks := uint64(ldr.SymSize(itablinkSym)) / uint64(ctxt.Arch.PtrSize)
-       moduledata.AddAddr(ctxt.Arch, itablinkSym)
-       moduledata.AddUint(ctxt.Arch, nitablinks)
-       moduledata.AddUint(ctxt.Arch, nitablinks)
+       slice(itablinkSym, nitablinks)
+
        // The ptab slice
        if ptab := ldr.Lookup("go:plugin.tabs", 0); ptab != 0 && ldr.AttrReachable(ptab) {
                ldr.SetAttrLocal(ptab, true)
@@ -731,14 +739,11 @@ func (ctxt *Link) symtab(pcln *pclntab) []sym.SymKind {
                        panic(fmt.Sprintf("go:plugin.tabs is %v, not SRODATA", ldr.SymType(ptab)))
                }
                nentries := uint64(len(ldr.Data(ptab)) / 8) // sizeof(nameOff) + sizeof(typeOff)
-               moduledata.AddAddr(ctxt.Arch, ptab)
-               moduledata.AddUint(ctxt.Arch, nentries)
-               moduledata.AddUint(ctxt.Arch, nentries)
+               slice(ptab, nentries)
        } else {
-               moduledata.AddUint(ctxt.Arch, 0)
-               moduledata.AddUint(ctxt.Arch, 0)
-               moduledata.AddUint(ctxt.Arch, 0)
+               nilSlice()
        }
+
        if ctxt.BuildMode == BuildModePlugin {
                addgostring(ctxt, ldr, moduledata, "go:link.thispluginpath", objabi.PathToPrefix(*flagPluginPath))
 
@@ -755,15 +760,11 @@ func (ctxt *Link) symtab(pcln *pclntab) []sym.SymKind {
                        hash := ldr.Lookup("go:link.pkghash."+l.Pkg, 0)
                        pkghashes.AddAddr(ctxt.Arch, hash)
                }
-               moduledata.AddAddr(ctxt.Arch, pkghashes.Sym())
-               moduledata.AddUint(ctxt.Arch, uint64(len(ctxt.Library)))
-               moduledata.AddUint(ctxt.Arch, uint64(len(ctxt.Library)))
+               slice(pkghashes.Sym(), uint64(len(ctxt.Library)))
        } else {
                moduledata.AddUint(ctxt.Arch, 0) // pluginpath
                moduledata.AddUint(ctxt.Arch, 0)
-               moduledata.AddUint(ctxt.Arch, 0) // pkghashes slice
-               moduledata.AddUint(ctxt.Arch, 0)
-               moduledata.AddUint(ctxt.Arch, 0)
+               nilSlice() // pkghashes slice
        }
        // Add inittasks slice
        t := ctxt.mainInittasks
@@ -809,15 +810,11 @@ func (ctxt *Link) symtab(pcln *pclntab) []sym.SymKind {
                        modulehashes.AddAddr(ctxt.Arch, abihash)
                }
 
-               moduledata.AddAddr(ctxt.Arch, modulehashes.Sym())
-               moduledata.AddUint(ctxt.Arch, uint64(len(ctxt.Shlibs)))
-               moduledata.AddUint(ctxt.Arch, uint64(len(ctxt.Shlibs)))
+               slice(modulehashes.Sym(), uint64(len(ctxt.Shlibs)))
        } else {
                moduledata.AddUint(ctxt.Arch, 0) // modulename
                moduledata.AddUint(ctxt.Arch, 0)
-               moduledata.AddUint(ctxt.Arch, 0) // moduleshashes slice
-               moduledata.AddUint(ctxt.Arch, 0)
-               moduledata.AddUint(ctxt.Arch, 0)
+               nilSlice() // moduleshashes slice
        }
 
        hasmain := ctxt.BuildMode == BuildModeExe || ctxt.BuildMode == BuildModePIE