[dev.link] cmd/internal/obj: add dump of aux symbols for -S=2

For compiler developers interested in seeing DWARF generation details,
this patch provides symbol "debug asm" dumps for DWARF aux symbols
when -S=2 is in effect.

Change-Id: I5a0b6b65ce7b708948cbbf23c6b0d279bd4f8d9f
Reviewed-on: https://go-review.googlesource.com/c/go/+/223017
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/cmd/internal/obj/objfile.go b/src/cmd/internal/obj/objfile.go
index 4669e415cc757a318f48d09055a5fca0e327237e..0f73e48b05ce21183812dec10863174fa991b0dd 100644 (file)
--- a/src/cmd/internal/obj/objfile.go
+++ b/src/cmd/internal/obj/objfile.go
@@ -21,7 +21,11 @@ func WriteObjFile(ctxt *Link, bout *bio.Writer, pkgpath string) {
 }
 
 func (ctxt *Link) writeSymDebug(s *LSym) {
-       fmt.Fprintf(ctxt.Bso, "%s ", s.Name)
+       ctxt.writeSymDebugNamed(s, s.Name)
+}
+
+func (ctxt *Link) writeSymDebugNamed(s *LSym, name string) {
+       fmt.Fprintf(ctxt.Bso, "%s ", name)
        if s.Type != 0 {
                fmt.Fprintf(ctxt.Bso, "%v ", s.Type)
        }

diff --git a/src/cmd/internal/obj/objfile2.go b/src/cmd/internal/obj/objfile2.go
index dc492733ac5cd9b88621c5f319b1d15d455daa16..9ccbcd5352af02e139a43d2b9860fee2bf799966 100644 (file)
--- a/src/cmd/internal/obj/objfile2.go
+++ b/src/cmd/internal/obj/objfile2.go
@@ -18,9 +18,8 @@ import (
 
 // Entry point of writing new object file.
 func WriteObjFile2(ctxt *Link, b *bio.Writer, pkgpath string) {
-       if ctxt.Debugasm > 0 {
-               ctxt.traverseSyms(traverseDefs, ctxt.writeSymDebug)
-       }
+
+       debugAsmEmit(ctxt)
 
        genFuncInfoSyms(ctxt)
 
@@ -434,3 +433,28 @@ func genFuncInfoSyms(ctxt *Link) {
        }
        ctxt.defs = append(ctxt.defs, infosyms...)
 }
+
+// debugDumpAux is a dumper for selected aux symbols.
+func writeAuxSymDebug(ctxt *Link, par *LSym, aux *LSym) {
+       // Most aux symbols (ex: funcdata) are not interesting--
+       // pick out just the DWARF ones for now.
+       if aux.Type != objabi.SDWARFLOC &&
+               aux.Type != objabi.SDWARFINFO &&
+               aux.Type != objabi.SDWARFLINES &&
+               aux.Type != objabi.SDWARFRANGE {
+               return
+       }
+       ctxt.writeSymDebugNamed(aux, "aux for "+par.Name)
+}
+
+func debugAsmEmit(ctxt *Link) {
+       if ctxt.Debugasm > 0 {
+               ctxt.traverseSyms(traverseDefs, ctxt.writeSymDebug)
+               if ctxt.Debugasm > 1 {
+                       fn := func(par *LSym, aux *LSym) {
+                               writeAuxSymDebug(ctxt, par, aux)
+                       }
+                       ctxt.traverseAuxSyms(fn)
+               }
+       }
+}

diff --git a/src/cmd/internal/obj/sym.go b/src/cmd/internal/obj/sym.go
index e1e749db92e2163c0a4bae5f39ae4079df8d78c4..818d464c91eade60557c57340e5d5392a2020d0b 100644 (file)
--- a/src/cmd/internal/obj/sym.go
+++ b/src/cmd/internal/obj/sym.go
@@ -294,28 +294,58 @@ func (ctxt *Link) traverseSyms(flag traverseFlag, fn func(*LSym)) {
                                        fn(s.Gotype)
                                }
                                if s.Type == objabi.STEXT {
-                                       pc := &s.Func.Pcln
-                                       for _, d := range pc.Funcdata {
-                                               if d != nil {
-                                                       fn(d)
-                                               }
-                                       }
-                                       for _, f := range pc.File {
-                                               if fsym := ctxt.Lookup(f); fsym != nil {
-                                                       fn(fsym)
-                                               }
-                                       }
-                                       for _, call := range pc.InlTree.nodes {
-                                               if call.Func != nil {
-                                                       fn(call.Func)
-                                               }
-                                               f, _ := linkgetlineFromPos(ctxt, call.Pos)
-                                               if fsym := ctxt.Lookup(f); fsym != nil {
-                                                       fn(fsym)
-                                               }
+                                       f := func(parent *LSym, aux *LSym) {
+                                               fn(aux)
                                        }
+                                       ctxt.traverseFuncAux(s, f)
                                }
                        }
                }
        }
 }
+
+func (ctxt *Link) traverseFuncAux(fsym *LSym, fn func(parent *LSym, aux *LSym)) {
+       pc := &fsym.Func.Pcln
+       for _, d := range pc.Funcdata {
+               if d != nil {
+                       fn(fsym, d)
+               }
+       }
+       for _, f := range pc.File {
+               if filesym := ctxt.Lookup(f); filesym != nil {
+                       fn(fsym, filesym)
+               }
+       }
+       for _, call := range pc.InlTree.nodes {
+               if call.Func != nil {
+                       fn(fsym, call.Func)
+               }
+               f, _ := linkgetlineFromPos(ctxt, call.Pos)
+               if filesym := ctxt.Lookup(f); filesym != nil {
+                       fn(fsym, filesym)
+               }
+       }
+       dwsyms := []*LSym{fsym.Func.dwarfRangesSym, fsym.Func.dwarfLocSym}
+       for _, dws := range dwsyms {
+               if dws == nil || dws.Size == 0 {
+                       continue
+               }
+               fn(fsym, dws)
+       }
+}
+
+// Traverse aux symbols, calling fn for each sym/aux pair.
+func (ctxt *Link) traverseAuxSyms(fn func(parent *LSym, aux *LSym)) {
+       lists := [][]*LSym{ctxt.Text, ctxt.Data, ctxt.ABIAliases}
+       for _, list := range lists {
+               for _, s := range list {
+                       if s.Gotype != nil {
+                               fn(s, s.Gotype)
+                       }
+                       if s.Type != objabi.STEXT {
+                               continue
+                       }
+                       ctxt.traverseFuncAux(s, fn)
+               }
+       }
+}