cmd/compile/internal: decouple scope tracking from location lists

We're trying to enable location lists by default, and it's easier to do
that if we don't have to worry about scope tracking at the same time.
We can evaluate their performance impact separately.

However, that does mean that "err" is ambiguous in the test case, so
rename it to err2 for now.

Change-Id: I24f119016185c52b7d9affc74207f6a5b450fb6f
Reviewed-on: https://go-review.googlesource.com/89355
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

src/cmd/compile/internal/gc/main.go

@@ -405,7 +405,7 @@ func Main(archInit func(*Arch)) {
 		Debug['l'] = 1 - Debug['l']
 	}
 
-	trackScopes = flagDWARF && ((Debug['l'] == 0 && Debug['N'] != 0) || Ctxt.Flag_locationlists)
+	trackScopes = flagDWARF && (Debug['l'] == 0 && Debug['N'] != 0)
 
 	Widthptr = thearch.LinkArch.PtrSize
 	Widthreg = thearch.LinkArch.RegSize

src/cmd/compile/internal/ssa/testdata/hist.gdb-dbg.nexts

@@ -14,64 +14,64 @@ hist =  []int = {0, 0, 0, 0, 0, 0, 0}
 73:		scanner := bufio.NewScanner(reader)
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
 i = 1
 81:			hist = ensure(int(i), hist)
 82:			hist[int(i)]++
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
 i = 1
 81:			hist = ensure(int(i), hist)
 82:			hist[int(i)]++
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
 i = 1
 81:			hist = ensure(int(i), hist)
 82:			hist[int(i)]++
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
 i = 2
 81:			hist = ensure(int(i), hist)
 82:			hist[int(i)]++
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
 i = 2
 81:			hist = ensure(int(i), hist)
 82:			hist[int(i)]++
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
 i = 2
 81:			hist = ensure(int(i), hist)
 82:			hist[int(i)]++
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
 i = 4
 81:			hist = ensure(int(i), hist)
 82:			hist[int(i)]++
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
 i = 4
 81:			hist = ensure(int(i), hist)
 82:			hist[int(i)]++
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
 i = 5
 81:			hist = ensure(int(i), hist)
 82:			hist[int(i)]++

src/cmd/compile/internal/ssa/testdata/hist.gdb-opt.nexts

@@ -22,9 +22,9 @@ dy = <Optimized out, as expected>
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 scanner = (struct bufio.Scanner *) <A>
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
-err = {tab = 0x0, data = 0x0}
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
+err2 = {tab = 0x0, data = 0x0}
 hist =  []int = {0, 0, 0, 0, 0, 0, 0}
 i = 1
 81:			hist = ensure(int(i), hist)
@@ -32,9 +32,9 @@ i = 1
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 scanner = (struct bufio.Scanner *) <A>
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
-err = {tab = 0x0, data = 0x0}
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
+err2 = {tab = 0x0, data = 0x0}
 hist =  []int = {0, 1, 0, 0, 0, 0, 0}
 i = 1
 81:			hist = ensure(int(i), hist)
@@ -42,9 +42,9 @@ i = 1
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 scanner = (struct bufio.Scanner *) <A>
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
-err = {tab = 0x0, data = 0x0}
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
+err2 = {tab = 0x0, data = 0x0}
 hist =  []int = {0, 2, 0, 0, 0, 0, 0}
 i = 1
 81:			hist = ensure(int(i), hist)
@@ -52,9 +52,9 @@ i = 1
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 scanner = (struct bufio.Scanner *) <A>
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
-err = {tab = 0x0, data = 0x0}
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
+err2 = {tab = 0x0, data = 0x0}
 hist =  []int = {0, 3, 0, 0, 0, 0, 0}
 i = 2
 81:			hist = ensure(int(i), hist)
@@ -62,9 +62,9 @@ i = 2
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 scanner = (struct bufio.Scanner *) <A>
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
-err = {tab = 0x0, data = 0x0}
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
+err2 = {tab = 0x0, data = 0x0}
 hist =  []int = {0, 3, 1, 0, 0, 0, 0}
 i = 2
 81:			hist = ensure(int(i), hist)
@@ -72,9 +72,9 @@ i = 2
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 scanner = (struct bufio.Scanner *) <A>
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
-err = {tab = 0x0, data = 0x0}
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
+err2 = {tab = 0x0, data = 0x0}
 hist =  []int = {0, 3, 2, 0, 0, 0, 0}
 i = 2
 81:			hist = ensure(int(i), hist)
@@ -82,9 +82,9 @@ i = 2
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 scanner = (struct bufio.Scanner *) <A>
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
-err = {tab = 0x0, data = 0x0}
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
+err2 = {tab = 0x0, data = 0x0}
 hist =  []int = {0, 3, 3, 0, 0, 0, 0}
 i = 4
 81:			hist = ensure(int(i), hist)
@@ -92,9 +92,9 @@ i = 4
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 scanner = (struct bufio.Scanner *) <A>
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
-err = {tab = 0x0, data = 0x0}
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
+err2 = {tab = 0x0, data = 0x0}
 hist =  []int = {0, 3, 3, 0, 1, 0, 0}
 i = 4
 81:			hist = ensure(int(i), hist)
@@ -102,9 +102,9 @@ i = 4
 74:		for scanner.Scan() { //gdb-opt=(scanner/A)
 scanner = (struct bufio.Scanner *) <A>
 75:			s := scanner.Text()
-76:			i, err := strconv.ParseInt(s, 10, 64)
-77:			if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
-err = {tab = 0x0, data = 0x0}
+76:			i, err2 := strconv.ParseInt(s, 10, 64)
+77:			if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
+err2 = {tab = 0x0, data = 0x0}
 hist =  []int = {0, 3, 3, 0, 2, 0, 0}
 i = 5
 81:			hist = ensure(int(i), hist)

src/cmd/compile/internal/ssa/testdata/hist.go

@@ -73,9 +73,9 @@ func test() {
 	scanner := bufio.NewScanner(reader)
 	for scanner.Scan() { //gdb-opt=(scanner/A)
 		s := scanner.Text()
-		i, err := strconv.ParseInt(s, 10, 64)
-		if err != nil { //gdb-dbg=(i) //gdb-opt=(err,hist,i)
-			fmt.Fprintf(os.Stderr, "There was an error: %v\n", err)
+		i, err2 := strconv.ParseInt(s, 10, 64)
+		if err2 != nil { //gdb-dbg=(i) //gdb-opt=(err2,hist,i)
+			fmt.Fprintf(os.Stderr, "There was an error: %v\n", err2)
 			return
 		}
 		hist = ensure(int(i), hist)