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https://github.com/golang/go
synced 2024-09-04 23:44:16 +00:00
cmd/compile: use innermost line number for -S
When functions are inlined, for instructions in the inlined body, does -S print the location of the call, or the location of the body? Right now, we do the former. I'd like to do the latter by default, it makes much more sense when reading disassembly. With mid-stack inlining enabled in more cases, this quandry will come up more often. The original behavior is still available with -S=2. Some tests use this mode (so they can find assembly generated by a particular source line). This helped me with understanding what the compiler was doing while fixing #29007. Change-Id: Id14a3a41e1b18901e7c5e460aa4caf6d940ed064 Reviewed-on: https://go-review.googlesource.com/c/153241 Reviewed-by: David Chase <drchase@google.com>
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@ -36,7 +36,7 @@ func main() {
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ctxt := obj.Linknew(architecture.LinkArch)
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if *flags.PrintOut {
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ctxt.Debugasm = true
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ctxt.Debugasm = 1
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}
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ctxt.Flag_dynlink = *flags.Dynlink
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ctxt.Flag_shared = *flags.Shared || *flags.Dynlink
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@ -8,7 +8,6 @@ import (
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"bytes"
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"internal/testenv"
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"io/ioutil"
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"log"
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"os"
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"os/exec"
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"path/filepath"
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@ -24,7 +23,7 @@ func TestScanfRemoval(t *testing.T) {
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// Make a directory to work in.
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dir, err := ioutil.TempDir("", "issue6853a-")
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if err != nil {
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log.Fatalf("could not create directory: %v", err)
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t.Fatalf("could not create directory: %v", err)
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}
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defer os.RemoveAll(dir)
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@ -32,7 +31,7 @@ func TestScanfRemoval(t *testing.T) {
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src := filepath.Join(dir, "test.go")
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f, err := os.Create(src)
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if err != nil {
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log.Fatalf("could not create source file: %v", err)
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t.Fatalf("could not create source file: %v", err)
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}
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f.Write([]byte(`
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package main
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@ -50,17 +49,17 @@ func main() {
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cmd := exec.Command(testenv.GoToolPath(t), "build", "-o", dst, src)
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out, err := cmd.CombinedOutput()
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if err != nil {
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log.Fatalf("could not build target: %v", err)
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t.Fatalf("could not build target: %v", err)
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}
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// Check destination to see if scanf code was included.
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cmd = exec.Command(testenv.GoToolPath(t), "tool", "nm", dst)
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out, err = cmd.CombinedOutput()
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if err != nil {
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log.Fatalf("could not read target: %v", err)
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t.Fatalf("could not read target: %v", err)
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}
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if bytes.Contains(out, []byte("scanInt")) {
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log.Fatalf("scanf code not removed from helloworld")
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t.Fatalf("scanf code not removed from helloworld")
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}
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}
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@ -71,7 +70,7 @@ func TestDashS(t *testing.T) {
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// Make a directory to work in.
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dir, err := ioutil.TempDir("", "issue14515-")
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if err != nil {
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log.Fatalf("could not create directory: %v", err)
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t.Fatalf("could not create directory: %v", err)
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}
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defer os.RemoveAll(dir)
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@ -79,7 +78,7 @@ func TestDashS(t *testing.T) {
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src := filepath.Join(dir, "test.go")
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f, err := os.Create(src)
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if err != nil {
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log.Fatalf("could not create source file: %v", err)
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t.Fatalf("could not create source file: %v", err)
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}
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f.Write([]byte(`
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package main
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@ -94,7 +93,7 @@ func main() {
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cmd := exec.Command(testenv.GoToolPath(t), "build", "-gcflags", "-S", "-o", filepath.Join(dir, "test"), src)
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out, err := cmd.CombinedOutput()
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if err != nil {
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log.Fatalf("could not build target: %v", err)
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t.Fatalf("could not build target: %v", err)
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}
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patterns := []string{
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@ -39,7 +39,6 @@ var (
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var (
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Debug_append int
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Debug_asm bool
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Debug_closure int
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Debug_compilelater int
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debug_dclstack int
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@ -195,7 +194,7 @@ func Main(archInit func(*Arch)) {
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objabi.Flagcount("K", "debug missing line numbers", &Debug['K'])
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objabi.Flagcount("L", "show full file names in error messages", &Debug['L'])
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objabi.Flagcount("N", "disable optimizations", &Debug['N'])
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flag.BoolVar(&Debug_asm, "S", false, "print assembly listing")
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objabi.Flagcount("S", "print assembly listing", &Debug['S'])
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objabi.AddVersionFlag() // -V
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objabi.Flagcount("W", "debug parse tree after type checking", &Debug['W'])
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flag.StringVar(&asmhdr, "asmhdr", "", "write assembly header to `file`")
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@ -265,7 +264,7 @@ func Main(archInit func(*Arch)) {
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Ctxt.Flag_dynlink = flag_dynlink
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Ctxt.Flag_optimize = Debug['N'] == 0
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Ctxt.Debugasm = Debug_asm
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Ctxt.Debugasm = Debug['S']
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Ctxt.Debugvlog = Debug_vlog
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if flagDWARF {
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Ctxt.DebugInfo = debuginfo
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@ -1330,6 +1329,7 @@ var concurrentFlagOK = [256]bool{
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'l': true, // disable inlining
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'w': true, // all printing happens before compilation
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'W': true, // all printing happens before compilation
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'S': true, // printing disassembly happens at the end (but see concurrentBackendAllowed below)
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}
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func concurrentBackendAllowed() bool {
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@ -1338,9 +1338,9 @@ func concurrentBackendAllowed() bool {
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return false
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}
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}
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// Debug_asm by itself is ok, because all printing occurs
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// Debug['S'] by itself is ok, because all printing occurs
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// while writing the object file, and that is non-concurrent.
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// Adding Debug_vlog, however, causes Debug_asm to also print
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// Adding Debug_vlog, however, causes Debug['S'] to also print
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// while flushing the plist, which happens concurrently.
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if Debug_vlog || debugstr != "" || debuglive > 0 {
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return false
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@ -599,7 +599,7 @@ type Pcdata struct {
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type Link struct {
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Headtype objabi.HeadType
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Arch *LinkArch
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Debugasm bool
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Debugasm int
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Debugvlog bool
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Debugpcln string
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Flag_shared bool
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@ -240,7 +240,13 @@ func (w *objWriter) writeSymDebug(s *LSym) {
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fmt.Fprintf(ctxt.Bso, "\n")
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if s.Type == objabi.STEXT {
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for p := s.Func.Text; p != nil; p = p.Link {
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fmt.Fprintf(ctxt.Bso, "\t%#04x %v\n", uint(int(p.Pc)), p)
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var s string
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if ctxt.Debugasm > 1 {
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s = p.String()
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} else {
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s = p.InnermostString()
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}
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fmt.Fprintf(ctxt.Bso, "\t%#04x %s\n", uint(int(p.Pc)), s)
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}
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}
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for i := 0; i < len(s.P); i += 16 {
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@ -283,7 +289,7 @@ func (w *objWriter) writeSymDebug(s *LSym) {
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func (w *objWriter) writeSym(s *LSym) {
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ctxt := w.ctxt
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if ctxt.Debugasm {
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if ctxt.Debugasm > 0 {
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w.writeSymDebug(s)
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}
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@ -27,7 +27,7 @@ func Flushplist(ctxt *Link, plist *Plist, newprog ProgAlloc, myimportpath string
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var plink *Prog
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for p := plist.Firstpc; p != nil; p = plink {
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if ctxt.Debugasm && ctxt.Debugvlog {
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if ctxt.Debugasm > 0 && ctxt.Debugvlog {
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fmt.Printf("obj: %v\n", p)
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}
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plink = p.Link
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@ -17,6 +17,9 @@ const REG_NONE = 0
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func (p *Prog) Line() string {
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return p.Ctxt.OutermostPos(p.Pos).Format(false, true)
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}
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func (p *Prog) InnermostLine() string {
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return p.Ctxt.InnermostPos(p.Pos).Format(false, true)
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}
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// InnermostLineNumber returns a string containing the line number for the
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// innermost inlined function (if any inlining) at p's position
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@ -118,6 +121,16 @@ func (p *Prog) String() string {
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return fmt.Sprintf("%.5d (%v)\t%s", p.Pc, p.Line(), p.InstructionString())
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}
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func (p *Prog) InnermostString() string {
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if p == nil {
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return "<nil Prog>"
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}
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if p.Ctxt == nil {
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return "<Prog without ctxt>"
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}
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return fmt.Sprintf("%.5d (%v)\t%s", p.Pc, p.InnermostLine(), p.InstructionString())
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}
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// InstructionString returns a string representation of the instruction without preceding
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// program counter or file and line number.
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func (p *Prog) InstructionString() string {
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@ -177,7 +190,7 @@ func (ctxt *Link) NewProg() *Prog {
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}
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func (ctxt *Link) CanReuseProgs() bool {
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return !ctxt.Debugasm
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return ctxt.Debugasm == 0
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}
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func Dconv(p *Prog, a *Addr) string {
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@ -642,7 +642,8 @@ func (t *test) run() {
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// against a set of regexps in comments.
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ops := t.wantedAsmOpcodes(long)
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for _, env := range ops.Envs() {
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cmdline := []string{"build", "-gcflags", "-S"}
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// -S=2 forces outermost line numbers when disassembling inlined code.
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cmdline := []string{"build", "-gcflags", "-S=2"}
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cmdline = append(cmdline, flags...)
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cmdline = append(cmdline, long)
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cmd := exec.Command(goTool(), cmdline...)
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