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cmd/compile: use src.NoXPos for entry-block constants

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The ssa backend is aggressive about placing constants and
certain other values in the Entry block.  It's implausible
that the original line numbers for these constants makes
any sort of sense when it appears to a user stepping in a
debugger, and they're also not that useful in dumps since
entry-block instructions tend to be constants (i.e.,
unlikely to be the cause of a crash).

Therefore, use src.NoXPos for any values that are explicitly
inserted into a function's entry block.

Passes all tests, including ssa/debug_test.go with both
gdb and a fairly recent dlv.  Hand-verified that it solves
the reported problem; constructed a test that reproduced
a problem, and fixed it.

Modified test harness to allow injection of slightly more
interesting inputs.

Fixes #22558.

Change-Id: I4476927067846bc4366da7793d2375c111694c55
Reviewed-on: https://go-review.googlesource.com/81215
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
David Chase 2017-11-30 15:11:34 -05:00 committed by Keith Randall
parent d4f48e3ff9
commit f22cf7131a
13 changed files with 110 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
src/cmd/compile/internal/gc/ssa.go
View File

@ -493,27 +493,27 @@ func (s *state) entryNewValue0(op ssa.Op, t *types.Type) *ssa.Value {
// entryNewValue0A adds a new value with no arguments and an aux value to the entry block.
func (s *state) entryNewValue0A(op ssa.Op, t *types.Type, aux interface{}) *ssa.Value {
return s.f.Entry.NewValue0A(s.peekPos(), op, t, aux)
return s.f.Entry.NewValue0A(src.NoXPos, op, t, aux)
}
// entryNewValue1 adds a new value with one argument to the entry block.
func (s *state) entryNewValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
return s.f.Entry.NewValue1(s.peekPos(), op, t, arg)
return s.f.Entry.NewValue1(src.NoXPos, op, t, arg)
}
// entryNewValue1 adds a new value with one argument and an auxint value to the entry block.
func (s *state) entryNewValue1I(op ssa.Op, t *types.Type, auxint int64, arg *ssa.Value) *ssa.Value {
return s.f.Entry.NewValue1I(s.peekPos(), op, t, auxint, arg)
return s.f.Entry.NewValue1I(src.NoXPos, op, t, auxint, arg)
}
// entryNewValue1A adds a new value with one argument and an aux value to the entry block.
func (s *state) entryNewValue1A(op ssa.Op, t *types.Type, aux interface{}, arg *ssa.Value) *ssa.Value {
return s.f.Entry.NewValue1A(s.peekPos(), op, t, aux, arg)
return s.f.Entry.NewValue1A(src.NoXPos, op, t, aux, arg)
}
// entryNewValue2 adds a new value with two arguments to the entry block.
func (s *state) entryNewValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
return s.f.Entry.NewValue2(s.peekPos(), op, t, arg0, arg1)
return s.f.Entry.NewValue2(src.NoXPos, op, t, arg0, arg1)
}
// const* routines add a new const value to the entry block.

11
src/cmd/compile/internal/ssa/debug_test.go
View File

@ -135,6 +135,9 @@ func TestNexting(t *testing.T) {
t.Run("dbg-race-"+debugger, func(t *testing.T) {
testNexting(t, "i22600", "dbg-race", "-N -l", "-race")
})
t.Run("dbg-22558-"+debugger, func(t *testing.T) {
testNexting(t, "i22558", "dbg-22558", "-N -l")
})
t.Run("opt-"+debugger, func(t *testing.T) {
// If this is test is run with a runtime compiled with -N -l, it is very likely to fail.
// This occurs in the noopt builders (for example).
@ -501,7 +504,7 @@ func (s *delveState) stepnext(ss string) bool {
func (s *delveState) start() {
if *dryrun {
fmt.Printf("%s\n", asCommandLine("", s.cmd))
fmt.Printf("b main.main\n")
fmt.Printf("b main.test\n")
fmt.Printf("c\n")
return
}
@ -511,7 +514,7 @@ func (s *delveState) start() {
panic(fmt.Sprintf("There was an error [start] running '%s', %v\n", line, err))
}
s.ioState.readExpecting(-1, 5000, "Type 'help' for list of commands.")
expect("Breakpoint [0-9]+ set at ", s.ioState.writeReadExpect("b main.main\n", "[(]dlv[)] "))
expect("Breakpoint [0-9]+ set at ", s.ioState.writeReadExpect("b main.test\n", "[(]dlv[)] "))
s.stepnext("c")
}
@ -555,7 +558,7 @@ func (s *gdbState) start() {
}
if *dryrun {
fmt.Printf("%s\n", asCommandLine("", s.cmd))
fmt.Printf("tbreak main.main\n")
fmt.Printf("tbreak main.test\n")
fmt.Printf("%s\n", run)
return
}
@ -565,7 +568,7 @@ func (s *gdbState) start() {
panic(fmt.Sprintf("There was an error [start] running '%s', %v\n", line, err))
}
s.ioState.readExpecting(-1, -1, "[(]gdb[)] ")
x := s.ioState.writeReadExpect("b main.main\n", "[(]gdb[)] ")
x := s.ioState.writeReadExpect("b main.test\n", "[(]gdb[)] ")
expect("Breakpoint [0-9]+ at", x)
s.stepnext(run)
}

5
src/cmd/compile/internal/ssa/func.go
View File

@ -407,6 +407,7 @@ func (b *Block) NewValue4(pos src.XPos, op Op, t *types.Type, arg0, arg1, arg2,
// constVal returns a constant value for c.
func (f *Func) constVal(pos src.XPos, op Op, t *types.Type, c int64, setAuxInt bool) *Value {
// TODO remove unused pos parameter, both here and in *func.ConstXXX callers.
if f.constants == nil {
f.constants = make(map[int64][]*Value)
}
@ -421,9 +422,9 @@ func (f *Func) constVal(pos src.XPos, op Op, t *types.Type, c int64, setAuxInt b
}
var v *Value
if setAuxInt {
v = f.Entry.NewValue0I(pos, op, t, c)
v = f.Entry.NewValue0I(src.NoXPos, op, t, c)
} else {
v = f.Entry.NewValue0(pos, op, t)
v = f.Entry.NewValue0(src.NoXPos, op, t)
}
f.constants[c] = append(vv, v)
return v

7
src/cmd/compile/internal/ssa/testdata/hist.dbg-dlv.nexts vendored
View File

@ -1,12 +1,12 @@
./testdata/hist.go
55: func main() {
55: func test() {
57: l := line{point{1 + zero, 2 + zero}, point{3 + zero, 4 + zero}}
58: tinycall() // this forces l etc to stack
59: dx := l.end.x - l.begin.x //gdb-dbg=(l.begin.x,l.end.y)//gdb-opt=(l,dx/O,dy/O)
60: dy := l.end.y - l.begin.y //gdb-opt=(dx,dy/O)
61: sink = dx + dy //gdb-opt=(dx,dy)
63: hist := make([]int, 7) //gdb-opt=(sink,dx/O,dy/O)
64: var reader io.Reader = strings.NewReader(cannedInput) //gdb-dbg=(hist/A,cannedInput/A)
63: hist := make([]int, 7) //gdb-opt=(dx/O,dy/O) // TODO sink is missing if this code is in 'test' instead of 'main'
64: var reader io.Reader = strings.NewReader(cannedInput) //gdb-dbg=(hist/A) // TODO cannedInput/A is missing if this code is in 'test' instead of 'main'
65: if len(os.Args) > 1 {
73: scanner := bufio.NewScanner(reader)
74: for scanner.Scan() { //gdb-opt=(scanner/A)
@ -96,3 +96,4 @@
87: if a == 0 { //gdb-opt=(a,n,t)
88: continue
86: for i, a := range hist {
98: }

8
src/cmd/compile/internal/ssa/testdata/hist.dbg-gdb.nexts vendored
View File

@ -1,5 +1,5 @@
src/cmd/compile/internal/ssa/testdata/hist.go
55: func main() {
55: func test() {
57: l := line{point{1 + zero, 2 + zero}, point{3 + zero, 4 + zero}}
58: tinycall() // this forces l etc to stack
59: dx := l.end.x - l.begin.x //gdb-dbg=(l.begin.x,l.end.y)//gdb-opt=(l,dx/O,dy/O)
@ -7,10 +7,9 @@ l.begin.x = 1
l.end.y = 4
60: dy := l.end.y - l.begin.y //gdb-opt=(dx,dy/O)
61: sink = dx + dy //gdb-opt=(dx,dy)
63: hist := make([]int, 7) //gdb-opt=(sink,dx/O,dy/O)
64: var reader io.Reader = strings.NewReader(cannedInput) //gdb-dbg=(hist/A,cannedInput/A)
63: hist := make([]int, 7) //gdb-opt=(dx/O,dy/O) // TODO sink is missing if this code is in 'test' instead of 'main'
64: var reader io.Reader = strings.NewReader(cannedInput) //gdb-dbg=(hist/A) // TODO cannedInput/A is missing if this code is in 'test' instead of 'main'
hist = []int = {0, 0, 0, 0, 0, 0, 0}
cannedInput = "1\n1\n1\n2\n2\n2\n4\n4\n5\n"
65: if len(os.Args) > 1 {
73: scanner := bufio.NewScanner(reader)
74: for scanner.Scan() { //gdb-opt=(scanner/A)
@ -121,3 +120,4 @@ t = 22
87: if a == 0 { //gdb-opt=(a,n,t)
88: continue
86: for i, a := range hist {
98: }

11
src/cmd/compile/internal/ssa/testdata/hist.go vendored
View File

@ -52,7 +52,7 @@ var cannedInput string = `1
5
`
func main() {
func test() {
// For #19868
l := line{point{1 + zero, 2 + zero}, point{3 + zero, 4 + zero}}
tinycall() // this forces l etc to stack
@ -60,8 +60,8 @@ func main() {
dy := l.end.y - l.begin.y //gdb-opt=(dx,dy/O)
sink = dx + dy //gdb-opt=(dx,dy)
// For #21098
hist := make([]int, 7) //gdb-opt=(sink,dx/O,dy/O)
var reader io.Reader = strings.NewReader(cannedInput) //gdb-dbg=(hist/A,cannedInput/A)
hist := make([]int, 7) //gdb-opt=(dx/O,dy/O) // TODO sink is missing if this code is in 'test' instead of 'main'
var reader io.Reader = strings.NewReader(cannedInput) //gdb-dbg=(hist/A) // TODO cannedInput/A is missing if this code is in 'test' instead of 'main'
if len(os.Args) > 1 {
var err error
reader, err = os.Open(os.Args[1])
@ -91,5 +91,8 @@ func main() {
n += a
fmt.Fprintf(os.Stderr, "%d\t%d\t%d\t%d\t%d\n", i, a, n, i*a, t) //gdb-dbg=(n,i,t)
}
}
func main() {
test()
}

7
src/cmd/compile/internal/ssa/testdata/hist.opt-dlv.nexts vendored
View File

@ -1,13 +1,13 @@
./testdata/hist.go
55: func main() {
55: func test() {
57: l := line{point{1 + zero, 2 + zero}, point{3 + zero, 4 + zero}}
58: tinycall() // this forces l etc to stack
57: l := line{point{1 + zero, 2 + zero}, point{3 + zero, 4 + zero}}
59: dx := l.end.x - l.begin.x //gdb-dbg=(l.begin.x,l.end.y)//gdb-opt=(l,dx/O,dy/O)
60: dy := l.end.y - l.begin.y //gdb-opt=(dx,dy/O)
61: sink = dx + dy //gdb-opt=(dx,dy)
63: hist := make([]int, 7) //gdb-opt=(sink,dx/O,dy/O)
64: var reader io.Reader = strings.NewReader(cannedInput) //gdb-dbg=(hist/A,cannedInput/A)
63: hist := make([]int, 7) //gdb-opt=(dx/O,dy/O) // TODO sink is missing if this code is in 'test' instead of 'main'
64: var reader io.Reader = strings.NewReader(cannedInput) //gdb-dbg=(hist/A) // TODO cannedInput/A is missing if this code is in 'test' instead of 'main'
65: if len(os.Args) > 1 {
74: for scanner.Scan() { //gdb-opt=(scanner/A)
76: i, err := strconv.ParseInt(s, 10, 64)
@ -102,3 +102,4 @@
92: fmt.Fprintf(os.Stderr, "%d\t%d\t%d\t%d\t%d\n", i, a, n, i*a, t) //gdb-dbg=(n,i,t)
87: if a == 0 { //gdb-opt=(a,n,t)
88: continue
98: }

8
src/cmd/compile/internal/ssa/testdata/hist.opt-gdb.nexts vendored
View File

@ -1,5 +1,5 @@
src/cmd/compile/internal/ssa/testdata/hist.go
55: func main() {
55: func test() {
57: l := line{point{1 + zero, 2 + zero}, point{3 + zero, 4 + zero}}
58: tinycall() // this forces l etc to stack
57: l := line{point{1 + zero, 2 + zero}, point{3 + zero, 4 + zero}}
@ -13,11 +13,10 @@ dy = <Optimized out, as expected>
61: sink = dx + dy //gdb-opt=(dx,dy)
dx = 2
dy = 2
63: hist := make([]int, 7) //gdb-opt=(sink,dx/O,dy/O)
sink = 4
63: hist := make([]int, 7) //gdb-opt=(dx/O,dy/O) // TODO sink is missing if this code is in 'test' instead of 'main'
dx = <Optimized out, as expected>
dy = <Optimized out, as expected>
64: var reader io.Reader = strings.NewReader(cannedInput) //gdb-dbg=(hist/A,cannedInput/A)
64: var reader io.Reader = strings.NewReader(cannedInput) //gdb-dbg=(hist/A) // TODO cannedInput/A is missing if this code is in 'test' instead of 'main'
65: if len(os.Args) > 1 {
73: scanner := bufio.NewScanner(reader)
74: for scanner.Scan() { //gdb-opt=(scanner/A)
@ -180,3 +179,4 @@ a = 0
n = 9
t = 22
88: continue
98: }

11
src/cmd/compile/internal/ssa/testdata/i22558.dbg-22558-dlv.nexts vendored Normal file
View File

@ -0,0 +1,11 @@
./testdata/i22558.go
19: func test(t *thing, u *thing) {
20: if t.next != nil {
23: fmt.Fprintf(os.Stderr, "%s\n", t.name)
24: u.self = u
25: t.self = t
26: t.next = u
27: for _, p := range t.stuff {
28: if isFoo(t, p) {
29: return
43: }

11
src/cmd/compile/internal/ssa/testdata/i22558.dbg-22558-gdb.nexts vendored Normal file
View File

@ -0,0 +1,11 @@
src/cmd/compile/internal/ssa/testdata/i22558.go
19: func test(t *thing, u *thing) {
20: if t.next != nil {
23: fmt.Fprintf(os.Stderr, "%s\n", t.name)
24: u.self = u
25: t.self = t
26: t.next = u
27: for _, p := range t.stuff {
28: if isFoo(t, p) {
29: return
43: }

43
src/cmd/compile/internal/ssa/testdata/i22558.go vendored Normal file
View File

@ -0,0 +1,43 @@
package main
import (
"fmt"
"os"
)
type big struct {
pile [768]int8
}
type thing struct {
name string
next *thing
self *thing
stuff []big
}
func test(t *thing, u *thing) {
if t.next != nil {
return
}
fmt.Fprintf(os.Stderr, "%s\n", t.name)
u.self = u
t.self = t
t.next = u
for _, p := range t.stuff {
if isFoo(t, p) {
return
}
}
}
//go:noinline
func isFoo(t *thing, b big) bool {
return true
}
func main() {
t := &thing{name: "t", self: nil, next: nil, stuff: make([]big, 1)}
u := thing{name: "u", self: t, next: t, stuff: make([]big, 1)}
test(t, &u)
}

3
src/cmd/compile/internal/ssa/testdata/i22600.dbg-race-gdb.nexts vendored
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@ -1,6 +1,7 @@
src/cmd/compile/internal/ssa/testdata/i22600.go
8: func main() {
8: func test() {
9: pwd, err := os.Getwd()
10: if err != nil {
14: fmt.Println(pwd)
15: }
19: }

6
src/cmd/compile/internal/ssa/testdata/i22600.go vendored
View File

@ -5,7 +5,7 @@ import (
"os"
)
func main() {
func test() {
pwd, err := os.Getwd()
if err != nil {
fmt.Println(err)
@ -13,3 +13,7 @@ func main() {
}
fmt.Println(pwd)
}
func main() {
test()
}