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cmd/compile,cmd/link: export int global consts to DWARF

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Updates #14517

Change-Id: I23ef88e71c89da12dffcadf5562ea2d7557b62cf
Reviewed-on: https://go-review.googlesource.com/61019
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Alessandro Arzilli 2017-09-03 11:59:18 +02:00 committed by Austin Clements
parent f366379d84
commit 9daee93121
6 changed files with 173 additions and 29 deletions
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61
src/cmd/compile/internal/gc/obj.go
View File

@ -203,24 +203,57 @@ func addptabs() {
}
}
func dumpGlobal(n *Node) {
if n.Type == nil {
Fatalf("external %v nil type\n", n)
}
if n.Class() == PFUNC {
return
}
if n.Sym.Pkg != localpkg {
return
}
dowidth(n.Type)
ggloblnod(n)
}
func dumpGlobalConst(n *Node) {
// only export typed constants
if n.Type == nil {
return
}
if n.Sym.Pkg != localpkg {
return
}
// only export integer constants for now
switch n.Type.Etype {
case TINT8:
case TINT16:
case TINT32:
case TINT64:
case TINT:
case TUINT8:
case TUINT16:
case TUINT32:
case TUINT64:
case TUINT:
case TUINTPTR:
// ok
default:
return
}
Ctxt.DwarfIntConst(myimportpath, n.Sym.Name, typesymname(n.Type), n.Int64())
}
func dumpglobls() {
// add globals
for _, n := range externdcl {
if n.Op != ONAME {
continue
switch n.Op {
case ONAME:
dumpGlobal(n)
case OLITERAL:
dumpGlobalConst(n)
}
if n.Type == nil {
Fatalf("external %v nil type\n", n)
}
if n.Class() == PFUNC {
continue
}
if n.Sym.Pkg != localpkg {
continue
}
dowidth(n.Type)
ggloblnod(n)
}
obj.SortSlice(funcsyms, func(i, j int) bool {

2
src/cmd/dist/build.go vendored
View File

@ -685,7 +685,7 @@ func install(dir string) {
// For package runtime, this writes go_asm.h, which
// the assembly files will need.
pkg := dir
if strings.HasPrefix(dir, "cmd/") {
if strings.HasPrefix(dir, "cmd/") && strings.Count(dir, "/") == 1 {
pkg = "main"
}
b := pathf("%s/_go_.a", workdir)

24
src/cmd/internal/dwarf/dwarf.go
View File

@ -21,6 +21,10 @@ const LocPrefix = "go.loc."
// RangePrefix is the prefix for all the symbols containing DWARF range lists.
const RangePrefix = "go.range."
// InfoConstPrefix is the prefix for all symbols containing DWARF info
// entries that contain constants.
const ConstInfoPrefix = "go.constinfo."
// Sym represents a symbol.
type Sym interface {
Len() int64
@ -234,6 +238,7 @@ const (
DW_ABRV_COMPUNIT
DW_ABRV_FUNCTION
DW_ABRV_VARIABLE
DW_ABRV_INT_CONSTANT
DW_ABRV_AUTO
DW_ABRV_AUTO_LOCLIST
DW_ABRV_PARAM
@ -310,6 +315,17 @@ var abbrevs = [DW_NABRV]dwAbbrev{
},
},
/* INT CONSTANT */
{
DW_TAG_constant,
DW_CHILDREN_no,
[]dwAttrForm{
{DW_AT_name, DW_FORM_string},
{DW_AT_type, DW_FORM_ref_addr},
{DW_AT_const_value, DW_FORM_sdata},
},
},
/* AUTO */
{
DW_TAG_variable,
@ -734,6 +750,14 @@ func HasChildren(die *DWDie) bool {
return abbrevs[die.Abbrev].children != 0
}
// PutIntConst writes a DIE for an integer constant
func PutIntConst(ctxt Context, info, typ Sym, name string, val int64) {
Uleb128put(ctxt, info, DW_ABRV_INT_CONSTANT)
putattr(ctxt, info, DW_ABRV_INT_CONSTANT, DW_FORM_string, DW_CLS_STRING, int64(len(name)), name)
putattr(ctxt, info, DW_ABRV_INT_CONSTANT, DW_FORM_ref_addr, DW_CLS_REFERENCE, 0, typ)
putattr(ctxt, info, DW_ABRV_INT_CONSTANT, DW_FORM_sdata, DW_CLS_CONSTANT, val, nil)
}
// PutFunc writes a DIE for a function to s.
// It also writes child DIEs for each variable in vars.
func PutFunc(ctxt Context, info, loc, ranges Sym, name string, external bool, startPC Sym, size int64, scopes []Scope) error {

13
src/cmd/internal/obj/objfile.go
View File

@ -499,3 +499,16 @@ func (ctxt *Link) populateDWARF(curfn interface{}, s *LSym) {
ctxt.Diag("emitting DWARF for %s failed: %v", s.Name, err)
}
}
// DwarfIntConst creates a link symbol for an integer constant with the
// given name, type and value.
func (ctxt *Link) DwarfIntConst(myimportpath, name, typename string, val int64) {
if myimportpath == "" {
return
}
s := ctxt.LookupInit(dwarf.ConstInfoPrefix+myimportpath, func(s *LSym) {
s.Type = objabi.SDWARFINFO
ctxt.Data = append(ctxt.Data, s)
})
dwarf.PutIntConst(dwCtxt{ctxt}, s, ctxt.Lookup(dwarf.InfoPrefix+typename), myimportpath+"."+name, val)
}

44
src/cmd/link/internal/ld/dwarf.go
View File

@ -972,6 +972,21 @@ func getCompilationDir() string {
return "/"
}
func importInfoSymbol(ctxt *Link, dsym *Symbol) {
dsym.Attr |= AttrNotInSymbolTable | AttrReachable
dsym.Type = SDWARFINFO
for _, r := range dsym.R {
if r.Type == objabi.R_DWARFREF && r.Sym.Size == 0 {
if Buildmode == BuildmodeShared {
// These type symbols may not be present in BuildmodeShared. Skip.
continue
}
n := nameFromDIESym(r.Sym)
defgotype(ctxt, ctxt.Syms.Lookup("type."+n, 0))
}
}
}
func writelines(ctxt *Link, syms []*Symbol) ([]*Symbol, []*Symbol) {
var dwarfctxt dwarf.Context = dwctxt{ctxt}
ls := ctxt.Syms.Lookup(".debug_line", 0)
@ -1064,18 +1079,7 @@ func writelines(ctxt *Link, syms []*Symbol) ([]*Symbol, []*Symbol) {
epcs = s
dsym := ctxt.Syms.Lookup(dwarf.InfoPrefix+s.Name, int(s.Version))
dsym.Attr |= AttrNotInSymbolTable | AttrReachable
dsym.Type = SDWARFINFO
for _, r := range dsym.R {
if r.Type == objabi.R_DWARFREF && r.Sym.Size == 0 {
if Buildmode == BuildmodeShared {
// These type symbols may not be present in BuildmodeShared. Skip.
continue
}
n := nameFromDIESym(r.Sym)
defgotype(ctxt, ctxt.Syms.Lookup("type."+n, 0))
}
}
importInfoSymbol(ctxt, dsym)
funcs = append(funcs, dsym)
finddebugruntimepath(s)
@ -1296,7 +1300,7 @@ const (
COMPUNITHEADERSIZE = 4 + 2 + 4 + 1
)
func writeinfo(ctxt *Link, syms []*Symbol, funcs []*Symbol, abbrevsym *Symbol) []*Symbol {
func writeinfo(ctxt *Link, syms []*Symbol, funcs, consts []*Symbol, abbrevsym *Symbol) []*Symbol {
infosec := ctxt.Syms.Lookup(".debug_info", 0)
infosec.R = infosec.R[:0]
infosec.Type = SDWARFINFO
@ -1330,6 +1334,10 @@ func writeinfo(ctxt *Link, syms []*Symbol, funcs []*Symbol, abbrevsym *Symbol) [
cu = append(cu, funcs...)
funcs = nil
}
if consts != nil {
cu = append(cu, consts...)
consts = nil
}
cu = putdies(ctxt, dwarfctxt, cu, compunit.Child)
var cusize int64
for _, child := range cu {
@ -1544,6 +1552,14 @@ func dwarfgeneratedebugsyms(ctxt *Link) {
genasmsym(ctxt, defdwsymb)
var consts []*Symbol
for _, lib := range ctxt.Library {
if s := ctxt.Syms.Lookup(dwarf.ConstInfoPrefix+lib.Pkg, 0); s != nil {
importInfoSymbol(ctxt, s)
consts = append(consts, s)
}
}
abbrev := writeabbrev(ctxt)
syms := []*Symbol{abbrev}
syms, funcs := writelines(ctxt, syms)
@ -1563,7 +1579,7 @@ func dwarfgeneratedebugsyms(ctxt *Link) {
// Need to reorder symbols so SDWARFINFO is after all SDWARFSECT
// (but we need to generate dies before writepub)
infosyms := writeinfo(ctxt, nil, funcs, abbrev)
infosyms := writeinfo(ctxt, nil, funcs, consts, abbrev)
syms = writepub(ctxt, ".debug_pubnames", ispubname, syms)
syms = writepub(ctxt, ".debug_pubtypes", ispubtype, syms)

58
src/runtime/runtime-gdb_test.go
View File

@ -381,3 +381,61 @@ func TestGdbAutotmpTypes(t *testing.T) {
}
}
}
const constsSource = `
package main
const aConstant int = 42
const largeConstant uint64 = ^uint64(0)
const minusOne int64 = -1
func main() {
println("hello world")
}
`
func TestGdbConst(t *testing.T) {
t.Parallel()
checkGdbEnvironment(t)
checkGdbVersion(t)
dir, err := ioutil.TempDir("", "go-build")
if err != nil {
t.Fatalf("failed to create temp directory: %v", err)
}
defer os.RemoveAll(dir)
// Build the source code.
src := filepath.Join(dir, "main.go")
err = ioutil.WriteFile(src, []byte(constsSource), 0644)
if err != nil {
t.Fatalf("failed to create file: %v", err)
}
cmd := exec.Command(testenv.GoToolPath(t), "build", "-gcflags=-N -l", "-o", "a.exe")
cmd.Dir = dir
out, err := testenv.CleanCmdEnv(cmd).CombinedOutput()
if err != nil {
t.Fatalf("building source %v\n%s", err, out)
}
// Execute gdb commands.
args := []string{"-nx", "-batch",
"-ex", "set startup-with-shell off",
"-ex", "break main.main",
"-ex", "run",
"-ex", "print main.aConstant",
"-ex", "print main.largeConstant",
"-ex", "print main.minusOne",
"-ex", "print 'runtime._MSpanInUse'",
filepath.Join(dir, "a.exe"),
}
got, _ := exec.Command("gdb", args...).CombinedOutput()
sgot := string(got)
t.Logf("output %q", sgot)
if strings.Index(sgot, "\n$1 = 42\n$2 = 18446744073709551615\n$3 = -1\n$4 = 1 '\\001'") < 0 {
t.Fatalf("output mismatch")
}
}