[dev.power64] all: merge default into dev.power64

Trivial merge except for src/runtime/asm_power64x.s and
src/runtime/signal_power64x.c

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/168950044

.hgtags

@@ -135,3 +135,4 @@ f8b50ad4cac4d4c4ecf48324b4f512f65e82cc1c go1.3beta1
 85518b1d6f8d6e16133b9ed2c9db6807522d37de go1.3.2
 f44017549ff9c3cc5eef74ebe7276cd0dfc066b6 go1.3.3
 f44017549ff9c3cc5eef74ebe7276cd0dfc066b6 release
+1fdfd7dfaedb1b7702141617e621ab7328a236a1 go1.4beta1

AUTHORS

@@ -65,6 +65,7 @@ Aulus Egnatius Varialus <varialus@gmail.com>
 Ben Olive <sionide21@gmail.com>
 Benjamin Black <b@b3k.us>
 Benny Siegert <bsiegert@gmail.com>
+Benoit Sigoure <tsunanet@gmail.com>
 Berengar Lehr <berengar.lehr@gmx.de>
 Billie Harold Cleek <bhcleek@gmail.com>
 Bjorn Tillenius <bjorn@tillenius.me>
@@ -156,6 +157,7 @@ Evan Shaw <chickencha@gmail.com>
 Ewan Chou <coocood@gmail.com>
 Fabrizio Milo <mistobaan@gmail.com>
 Fan Hongjian <fan.howard@gmail.com>
+Fastly, Inc.
 Fatih Arslan <fatih@arslan.io>
 Fazlul Shahriar <fshahriar@gmail.com>
 Felix Geisendörfer <haimuiba@gmail.com>
@@ -166,6 +168,7 @@ Francisco Souza <franciscossouza@gmail.com>
 Frederick Kelly Mayle III <frederickmayle@gmail.com>
 Fredrik Enestad <fredrik.enestad@soundtrackyourbrand.com>
 Frithjof Schulze <schulze@math.uni-hannover.de> <sfrithjof@gmail.com>
+Gabriel Aszalos <gabriel.aszalos@gmail.com>
 Gary Burd <gary@beagledreams.com>
 Gautham Thambidorai <gautham.dorai@gmail.com>
 Georg Reinke <guelfey@gmail.com>
@@ -315,6 +318,7 @@ Moriyoshi Koizumi <mozo@mozo.jp>
 Môshe van der Sterre <moshevds@gmail.com>
 Nan Deng <monnand@gmail.com>
 Nathan John Youngman <nj@nathany.com>
+Nathan P Finch <nate.finch@gmail.com>
 ngmoco, LLC
 Nicholas Katsaros <nick@nickkatsaros.com>
 Nicholas Presta <nick@nickpresta.ca> <nick1presta@gmail.com>

CONTRIBUTORS

@@ -104,6 +104,7 @@ Ben Lynn <benlynn@gmail.com>
 Ben Olive <sionide21@gmail.com>
 Benjamin Black <b@b3k.us>
 Benny Siegert <bsiegert@gmail.com>
+Benoit Sigoure <tsunanet@gmail.com>
 Berengar Lehr <Berengar.Lehr@gmx.de>
 Bill Neubauer <wcn@golang.org> <wcn@google.com> <bill.neubauer@gmail.com>
 Bill Thiede <couchmoney@gmail.com>
@@ -241,6 +242,7 @@ Fredrik Enestad <fredrik.enestad@soundtrackyourbrand.com>
 Frithjof Schulze <schulze@math.uni-hannover.de> <sfrithjof@gmail.com>
 Fumitoshi Ukai <ukai@google.com>
 Gaal Yahas <gaal@google.com>
+Gabriel Aszalos <gabriel.aszalos@gmail.com>
 Gary Burd <gary@beagledreams.com> <gary.burd@gmail.com>
 Gautham Thambidorai <gautham.dorai@gmail.com>
 Georg Reinke <guelfey@gmail.com>
@@ -299,6 +301,7 @@ Jason Del Ponte <delpontej@gmail.com>
 Jason Travis <infomaniac7@gmail.com>
 Jay Weisskopf <jay@jayschwa.net>
 Jean-Marc Eurin <jmeurin@google.com>
+Jed Denlea <jed@fastly.com>
 Jeff Hodges <jeff@somethingsimilar.com>
 Jeff R. Allen <jra@nella.org> <jeff.allen@gmail.com>
 Jeff Sickel <jas@corpus-callosum.com>
@@ -444,6 +447,7 @@ Môshe van der Sterre <moshevds@gmail.com>
 Mrunal Patel <mrunalp@gmail.com>
 Nan Deng <monnand@gmail.com>
 Nathan John Youngman <nj@nathany.com>
+Nathan P Finch <nate.finch@gmail.com>
 Nicholas Katsaros <nick@nickkatsaros.com>
 Nicholas Presta <nick@nickpresta.ca> <nick1presta@gmail.com>
 Nicholas Sullivan <nicholas.sullivan@gmail.com>

misc/cgo/test/cgo_test.go

@@ -62,5 +62,6 @@ func Test8517(t *testing.T)                  { test8517(t) }
 func Test8811(t *testing.T)                  { test8811(t) }
 func TestReturnAfterGrow(t *testing.T)       { testReturnAfterGrow(t) }
 func TestReturnAfterGrowFromGo(t *testing.T) { testReturnAfterGrowFromGo(t) }
+func Test9026(t *testing.T)                  { test9026(t) }
 
 func BenchmarkCgoCall(b *testing.B) { benchCgoCall(b) }

misc/cgo/test/issue6997_linux.go

@@ -34,7 +34,7 @@ func test6997(t *testing.T) {
 		if r == 0 {
 			t.Error("pthread finished but wasn't cancelled??")
 		}
-	case <-time.After(5 * time.Second):
+	case <-time.After(30 * time.Second):
 		t.Error("hung in pthread_cancel/pthread_join")
 	}
 }

misc/cgo/test/issue9026.go

+package cgotest
+
+/*
+typedef struct {} git_merge_file_input;
+
+typedef struct {} git_merge_file_options;
+
+void git_merge_file(
+        git_merge_file_input *in,
+        git_merge_file_options *opts) {}
+*/
+import "C"
+import (
+	"fmt"
+	"testing"
+)
+
+func test9026(t *testing.T) {
+	var in C.git_merge_file_input
+	var opts *C.git_merge_file_options
+	C.git_merge_file(&in, opts)
+
+	// Test that the generated type names are deterministic.
+	// (Previously this would fail about 10% of the time.)
+	//
+	// Brittle: the assertion may fail spuriously when the algorithm
+	// changes, but should remain stable otherwise.
+	got := fmt.Sprintf("%T %T", in, opts)
+	want := "cgotest._Ctype_struct___12 *cgotest._Ctype_struct___13"
+	if got != want {
+		t.Errorf("Non-deterministic type names: got %s, want %s", got, want)
+	}
+}

src/cmd/cgo/gcc.go

@@ -944,6 +944,8 @@ type typeConv struct {
 
 	// Map from types to incomplete pointers to those types.
 	ptrs map[dwarf.Type][]*Type
+	// Keys of ptrs in insertion order (deterministic worklist)
+	ptrKeys []dwarf.Type
 
 	// Predeclared types.
 	bool                                   ast.Expr
@@ -1061,16 +1063,17 @@ func (tr *TypeRepr) Set(repr string, fargs ...interface{}) {
 func (c *typeConv) FinishType(pos token.Pos) {
 	// Completing one pointer type might produce more to complete.
 	// Keep looping until they're all done.
-	for len(c.ptrs) > 0 {
-		for dtype := range c.ptrs {
+	for len(c.ptrKeys) > 0 {
+		dtype := c.ptrKeys[0]
+		c.ptrKeys = c.ptrKeys[1:]
+
 		// Note Type might invalidate c.ptrs[dtype].
 		t := c.Type(dtype, pos)
 		for _, ptr := range c.ptrs[dtype] {
 			ptr.Go.(*ast.StarExpr).X = t.Go
 			ptr.C.Set("%s*", t.C)
 		}
-			delete(c.ptrs, dtype)
-		}
+		c.ptrs[dtype] = nil // retain the map key
 	}
 }
 
@@ -1237,6 +1240,9 @@ func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
 		// Placeholder initialization; completed in FinishType.
 		t.Go = &ast.StarExpr{}
 		t.C.Set("<incomplete>*")
+		if _, ok := c.ptrs[dt.Type]; !ok {
+			c.ptrKeys = append(c.ptrKeys, dt.Type)
+		}
 		c.ptrs[dt.Type] = append(c.ptrs[dt.Type], t)
 
 	case *dwarf.QualType:

src/cmd/go/doc.go

@@ -247,7 +247,7 @@ The arguments are space-separated tokens or double-quoted strings
 passed to the generator as individual arguments when it is run.
 
 Quoted strings use Go syntax and are evaluated before execution; a
-quoted string appears a single argument to the generator.
+quoted string appears as a single argument to the generator.
 
 Go generate sets several variables when it runs the generator:
 
@@ -260,7 +260,7 @@ Go generate sets several variables when it runs the generator:
 	$GOPACKAGE
 		The name of the package of the file containing the directive.
 
-Other than variable substition and quoted-string evaluation, no
+Other than variable substitution and quoted-string evaluation, no
 special processing such as "globbing" is performed on the command
 line.
 

src/cmd/go/generate.go

@@ -58,7 +58,7 @@ Go generate sets several variables when it runs the generator:
 	$GOPACKAGE
 		The name of the package of the file containing the directive.
 
-Other than variable substition and quoted-string evaluation, no
+Other than variable substitution and quoted-string evaluation, no
 special processing such as "globbing" is performed on the command
 line.
 

src/cmd/internal/objfile/elf.go

@@ -8,6 +8,7 @@ package objfile
 
 import (
 	"debug/elf"
+	"fmt"
 	"os"
 )
 
@@ -77,3 +78,27 @@ func (f *elfFile) pcln() (textStart uint64, symtab, pclntab []byte, err error) {
 	}
 	return textStart, symtab, pclntab, nil
 }
+
+func (f *elfFile) text() (textStart uint64, text []byte, err error) {
+	sect := f.elf.Section(".text")
+	if sect == nil {
+		return 0, nil, fmt.Errorf("text section not found")
+	}
+	textStart = sect.Addr
+	text, err = sect.Data()
+	return
+}
+
+func (f *elfFile) goarch() string {
+	switch f.elf.Machine {
+	case elf.EM_386:
+		return "386"
+	case elf.EM_X86_64:
+		return "amd64"
+	case elf.EM_ARM:
+		return "arm"
+	case elf.EM_PPC64:
+		return "power64"
+	}
+	return ""
+}

src/cmd/internal/objfile/goobj.go

@@ -79,3 +79,15 @@ func (f *goobjFile) symbols() ([]Sym, error) {
 func (f *goobjFile) pcln() (textStart uint64, symtab, pclntab []byte, err error) {
 	return 0, nil, nil, fmt.Errorf("pcln not available in go object file")
 }
+
+// text does not make sense for Go object files, because
+// each function has a separate section.
+func (f *goobjFile) text() (textStart uint64, text []byte, err error) {
+	return 0, nil, fmt.Errorf("text not available in go object file")
+}
+
+// goarch makes sense but is not exposed in debug/goobj's API,
+// and we don't need it yet for any users of internal/objfile.
+func (f *goobjFile) goarch() string {
+	return "GOARCH unimplemented for debug/goobj files"
+}

src/cmd/internal/objfile/macho.go

@@ -85,6 +85,30 @@ func (f *machoFile) pcln() (textStart uint64, symtab, pclntab []byte, err error)
 	return textStart, symtab, pclntab, nil
 }
 
+func (f *machoFile) text() (textStart uint64, text []byte, err error) {
+	sect := f.macho.Section("__text")
+	if sect == nil {
+		return 0, nil, fmt.Errorf("text section not found")
+	}
+	textStart = sect.Addr
+	text, err = sect.Data()
+	return
+}
+
+func (f *machoFile) goarch() string {
+	switch f.macho.Cpu {
+	case macho.Cpu386:
+		return "386"
+	case macho.CpuAmd64:
+		return "amd64"
+	case macho.CpuArm:
+		return "arm"
+	case macho.CpuPpc64:
+		return "power64"
+	}
+	return ""
+}
+
 type uint64s []uint64
 
 func (x uint64s) Len() int           { return len(x) }

src/cmd/internal/objfile/objfile.go

@@ -14,6 +14,8 @@ import (
 type rawFile interface {
 	symbols() (syms []Sym, err error)
 	pcln() (textStart uint64, symtab, pclntab []byte, err error)
+	text() (textStart uint64, text []byte, err error)
+	goarch() string
 }
 
 // A File is an opened executable file.
@@ -70,3 +72,11 @@ func (f *File) PCLineTable() (*gosym.Table, error) {
 	}
 	return gosym.NewTable(symtab, gosym.NewLineTable(pclntab, textStart))
 }
+
+func (f *File) Text() (uint64, []byte, error) {
+	return f.raw.text()
+}
+
+func (f *File) GOARCH() string {
+	return f.raw.goarch()
+}

src/cmd/internal/objfile/pe.go

@@ -133,6 +133,25 @@ func (f *peFile) pcln() (textStart uint64, symtab, pclntab []byte, err error) {
 	return textStart, symtab, pclntab, nil
 }
 
+func (f *peFile) text() (textStart uint64, text []byte, err error) {
+	var imageBase uint64
+	switch oh := f.pe.OptionalHeader.(type) {
+	case *pe.OptionalHeader32:
+		imageBase = uint64(oh.ImageBase)
+	case *pe.OptionalHeader64:
+		imageBase = oh.ImageBase
+	default:
+		return 0, nil, fmt.Errorf("pe file format not recognized")
+	}
+	sect := f.pe.Section(".text")
+	if sect == nil {
+		return 0, nil, fmt.Errorf("text section not found")
+	}
+	textStart = imageBase + uint64(sect.VirtualAddress)
+	text, err = sect.Data()
+	return
+}
+
 func findPESymbol(f *pe.File, name string) (*pe.Symbol, error) {
 	for _, s := range f.Symbols {
 		if s.Name != name {
@@ -168,3 +187,15 @@ func loadPETable(f *pe.File, sname, ename string) ([]byte, error) {
 	}
 	return data[ssym.Value:esym.Value], nil
 }
+
+func (f *peFile) goarch() string {
+	// Not sure how to get the info we want from PE header.
+	// Look in symbol table for telltale rt0 symbol.
+	if _, err := findPESymbol(f.pe, "_rt0_386_windows"); err == nil {
+		return "386"
+	}
+	if _, err := findPESymbol(f.pe, "_rt0_amd64_windows"); err == nil {
+		return "amd64"
+	}
+	return ""
+}

src/cmd/internal/objfile/plan9obj.go

@@ -88,6 +88,16 @@ func (f *plan9File) pcln() (textStart uint64, symtab, pclntab []byte, err error)
 	return textStart, symtab, pclntab, nil
 }
 
+func (f *plan9File) text() (textStart uint64, text []byte, err error) {
+	sect := f.plan9.Section("text")
+	if sect == nil {
+		return 0, nil, fmt.Errorf("text section not found")
+	}
+	textStart = f.plan9.LoadAddress + f.plan9.HdrSize
+	text, err = sect.Data()
+	return
+}
+
 func findPlan9Symbol(f *plan9obj.File, name string) (*plan9obj.Sym, error) {
 	syms, err := f.Symbols()
 	if err != nil {
@@ -122,3 +132,15 @@ func loadPlan9Table(f *plan9obj.File, sname, ename string) ([]byte, error) {
 	textStart := f.LoadAddress + f.HdrSize
 	return data[ssym.Value-textStart : esym.Value-textStart], nil
 }
+
+func (f *plan9File) goarch() string {
+	switch f.plan9.Magic {
+	case plan9obj.Magic386:
+		return "386"
+	case plan9obj.MagicAMD64:
+		return "amd64"
+	case plan9obj.MagicARM:
+		return "arm"
+	}
+	return ""
+}

src/cmd/objdump/Makefile

-all: x86.go armasm.go
-
-x86.go: bundle
-	./bundle -p main -x x86_ rsc.io/x86/x86asm | gofmt >x86.go
-
-armasm.go: bundle
-	./bundle -p main -x arm_ rsc.io/arm/armasm | gofmt >armasm.go
-
-bundle:
-	go build -o bundle code.google.com/p/rsc/cmd/bundle

src/cmd/objdump/elf.go

-// Copyright 2013 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Parsing of ELF executables (Linux, FreeBSD, and so on).
-
-package main
-
-import (
-	"debug/elf"
-	"os"
-)
-
-func elfSymbols(f *os.File) (syms []Sym, goarch string) {
-	p, err := elf.NewFile(f)
-	if err != nil {
-		errorf("parsing %s: %v", f.Name(), err)
-		return
-	}
-
-	elfSyms, err := p.Symbols()
-	if err != nil {
-		errorf("parsing %s: %v", f.Name(), err)
-		return
-	}
-
-	switch p.Machine {
-	case elf.EM_X86_64:
-		goarch = "amd64"
-	case elf.EM_386:
-		goarch = "386"
-	case elf.EM_ARM:
-		goarch = "arm"
-	}
-
-	for _, s := range elfSyms {
-		sym := Sym{Addr: s.Value, Name: s.Name, Size: int64(s.Size), Code: '?'}
-		switch s.Section {
-		case elf.SHN_UNDEF:
-			sym.Code = 'U'
-		case elf.SHN_COMMON:
-			sym.Code = 'B'
-		default:
-			i := int(s.Section)
-			if i < 0 || i >= len(p.Sections) {
-				break
-			}
-			sect := p.Sections[i]
-			switch sect.Flags & (elf.SHF_WRITE | elf.SHF_ALLOC | elf.SHF_EXECINSTR) {
-			case elf.SHF_ALLOC | elf.SHF_EXECINSTR:
-				sym.Code = 'T'
-			case elf.SHF_ALLOC:
-				sym.Code = 'R'
-			case elf.SHF_ALLOC | elf.SHF_WRITE:
-				sym.Code = 'D'
-			}
-		}
-		if elf.ST_BIND(s.Info) == elf.STB_LOCAL {
-			sym.Code += 'a' - 'A'
-		}
-		syms = append(syms, sym)
-	}
-
-	return
-}

src/cmd/objdump/macho.go

-// Copyright 2013 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Parsing of Mach-O executables (OS X).
-
-package main
-
-import (
-	"debug/macho"
-	"os"
-	"sort"
-)
-
-func machoSymbols(f *os.File) (syms []Sym, goarch string) {
-	p, err := macho.NewFile(f)
-	if err != nil {
-		errorf("parsing %s: %v", f.Name(), err)
-		return
-	}
-
-	if p.Symtab == nil {
-		errorf("%s: no symbol table", f.Name())
-		return
-	}
-
-	switch p.Cpu {
-	case macho.Cpu386:
-		goarch = "386"
-	case macho.CpuAmd64:
-		goarch = "amd64"
-	case macho.CpuArm:
-		goarch = "arm"
-	}
-
-	// Build sorted list of addresses of all symbols.
-	// We infer the size of a symbol by looking at where the next symbol begins.
-	var addrs []uint64
-	for _, s := range p.Symtab.Syms {
-		addrs = append(addrs, s.Value)
-	}
-	sort.Sort(uint64s(addrs))
-
-	for _, s := range p.Symtab.Syms {
-		sym := Sym{Name: s.Name, Addr: s.Value, Code: '?'}
-		i := sort.Search(len(addrs), func(x int) bool { return addrs[x] > s.Value })
-		if i < len(addrs) {
-			sym.Size = int64(addrs[i] - s.Value)
-		}
-		if s.Sect == 0 {
-			sym.Code = 'U'
-		} else if int(s.Sect) <= len(p.Sections) {
-			sect := p.Sections[s.Sect-1]
-			switch sect.Seg {
-			case "__TEXT":
-				sym.Code = 'R'
-			case "__DATA":
-				sym.Code = 'D'
-			}
-			switch sect.Seg + " " + sect.Name {
-			case "__TEXT __text":
-				sym.Code = 'T'
-			case "__DATA __bss", "__DATA __noptrbss":
-				sym.Code = 'B'
-			}
-		}
-		syms = append(syms, sym)
-	}
-
-	return
-}
-
-type uint64s []uint64
-
-func (x uint64s) Len() int           { return len(x) }
-func (x uint64s) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
-func (x uint64s) Less(i, j int) bool { return x[i] < x[j] }

src/cmd/objdump/objdump_test.go

@@ -147,7 +147,7 @@ var x86Need = []string{
 var armNeed = []string{
 	"fmthello.go:6",
 	"TEXT main.main(SB)",
-	"B.LS main.main(SB)",
+	//"B.LS main.main(SB)", // TODO(rsc): restore; golang.org/issue/9021
 	"BL fmt.Println(SB)",
 	"RET",
 }

src/cmd/objdump/pe.go

-// Copyright 2013 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Parsing of PE executables (Microsoft Windows).
-
-package main
-
-import (
-	"debug/pe"
-	"os"
-	"sort"
-)
-
-func peSymbols(f *os.File) (syms []Sym, goarch string) {
-	p, err := pe.NewFile(f)
-	if err != nil {
-		errorf("parsing %s: %v", f.Name(), err)
-		return
-	}
-
-	// Build sorted list of addresses of all symbols.
-	// We infer the size of a symbol by looking at where the next symbol begins.
-	var addrs []uint64
-
-	var imageBase uint64
-	switch oh := p.OptionalHeader.(type) {
-	case *pe.OptionalHeader32:
-		imageBase = uint64(oh.ImageBase)
-		goarch = "386"
-	case *pe.OptionalHeader64:
-		imageBase = oh.ImageBase
-		goarch = "amd64"
-	default:
-		errorf("parsing %s: file format not recognized", f.Name())
-		return
-	}
-
-	for _, s := range p.Symbols {
-		const (
-			N_UNDEF = 0  // An undefined (extern) symbol
-			N_ABS   = -1 // An absolute symbol (e_value is a constant, not an address)
-			N_DEBUG = -2 // A debugging symbol
-		)
-		sym := Sym{Name: s.Name, Addr: uint64(s.Value), Code: '?'}
-		switch s.SectionNumber {
-		case N_UNDEF:
-			sym.Code = 'U'
-		case N_ABS:
-			sym.Code = 'C'
-		case N_DEBUG:
-			sym.Code = '?'
-		default:
-			if s.SectionNumber < 0 {
-				errorf("parsing %s: invalid section number %d", f.Name(), s.SectionNumber)
-				return
-			}
-			if len(p.Sections) < int(s.SectionNumber) {
-				errorf("parsing %s: section number %d is large then max %d", f.Name(), s.SectionNumber, len(p.Sections))
-				return
-			}
-			sect := p.Sections[s.SectionNumber-1]
-			const (
-				text  = 0x20
-				data  = 0x40
-				bss   = 0x80
-				permX = 0x20000000
-				permR = 0x40000000
-				permW = 0x80000000
-			)
-			ch := sect.Characteristics
-			switch {
-			case ch&text != 0:
-				sym.Code = 'T'
-			case ch&data != 0:
-				if ch&permW == 0 {
-					sym.Code = 'R'
-				} else {
-					sym.Code = 'D'
-				}
-			case ch&bss != 0:
-				sym.Code = 'B'
-			}
-			sym.Addr += imageBase + uint64(sect.VirtualAddress)
-		}
-		syms = append(syms, sym)
-		addrs = append(addrs, sym.Addr)
-	}
-
-	sort.Sort(uint64s(addrs))
-	for i := range syms {
-		j := sort.Search(len(addrs), func(x int) bool { return addrs[x] > syms[i].Addr })
-		if j < len(addrs) {
-			syms[i].Size = int64(addrs[j] - syms[i].Addr)
-		}
-	}
-
-	return
-}

src/cmd/objdump/plan9obj.go

-// Copyright 2014 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Parsing of Plan 9 a.out executables.
-
-package main
-
-import (
-	"debug/plan9obj"
-	"os"
-	"sort"
-)
-
-var validSymType = map[rune]bool{
-	'T': true,
-	't': true,
-	'D': true,
-	'd': true,
-	'B': true,
-	'b': true,
-}
-
-func plan9Symbols(f *os.File) (syms []Sym, goarch string) {
-	p, err := plan9obj.NewFile(f)
-	if err != nil {
-		errorf("parsing %s: %v", f.Name(), err)
-		return
-	}
-
-	plan9Syms, err := p.Symbols()
-	if err != nil {
-		errorf("parsing %s: %v", f.Name(), err)
-		return
-	}
-
-	switch p.Magic {
-	case plan9obj.MagicAMD64:
-		goarch = "amd64"
-	case plan9obj.Magic386:
-		goarch = "386"
-	case plan9obj.MagicARM:
-		goarch = "arm"
-	}
-
-	// Build sorted list of addresses of all symbols.
-	// We infer the size of a symbol by looking at where the next symbol begins.
-	var addrs []uint64
-	for _, s := range plan9Syms {
-		if !validSymType[s.Type] {
-			continue
-		}
-		addrs = append(addrs, s.Value)
-	}
-	sort.Sort(uint64s(addrs))
-
-	for _, s := range plan9Syms {
-		if !validSymType[s.Type] {
-			continue
-		}
-		sym := Sym{Addr: s.Value, Name: s.Name, Code: rune(s.Type)}
-		i := sort.Search(len(addrs), func(x int) bool { return addrs[x] > s.Value })
-		if i < len(addrs) {
-			sym.Size = int64(addrs[i] - s.Value)
-		}
-		syms = append(syms, sym)
-	}
-
-	return
-}

src/database/sql/fakedb_test.go

@@ -141,6 +141,8 @@ type Dummy struct {
 }
 
 func TestDrivers(t *testing.T) {
+	unregisterAllDrivers()
+	Register("test", fdriver)
 	Register("invalid", Dummy{})
 	all := Drivers()
 	if len(all) < 2 || !sort.StringsAreSorted(all) || !contains(all, "test") || !contains(all, "invalid") {

src/database/sql/sql.go

@@ -37,6 +37,11 @@ func Register(name string, driver driver.Driver) {
 	drivers[name] = driver
 }
 
+func unregisterAllDrivers() {
+	// For tests.
+	drivers = make(map[string]driver.Driver)
+}
+
 // Drivers returns a sorted list of the names of the registered drivers.
 func Drivers() []string {
 	var list []string

src/net/http/main_test.go

@@ -70,7 +70,7 @@ func goroutineLeaked() bool {
 	}
 	fmt.Fprintf(os.Stderr, "Too many goroutines running after net/http test(s).\n")
 	for stack, count := range stackCount {
-		fmt.Fprintf(os.Stderr, "%d instances of:\n%s", count, stack)
+		fmt.Fprintf(os.Stderr, "%d instances of:\n%s\n", count, stack)
 	}
 	return true
 }

src/runtime/asm_386.s

@@ -2284,3 +2284,9 @@ TEXT _cgo_topofstack(SB),NOSPLIT,$0
 	MOVL	m_curg(AX), AX
 	MOVL	(g_stack+stack_hi)(AX), AX
 	RET
+
+// The top-most function running on a goroutine
+// returns to goexit+PCQuantum.
+TEXT runtime·goexit(SB),NOSPLIT,$0-0
+	BYTE	$0x90	// NOP
+	CALL	runtime·goexit1(SB)	// does not return

src/runtime/asm_amd64.s

@@ -2229,3 +2229,9 @@ TEXT _cgo_topofstack(SB),NOSPLIT,$0
 	MOVQ	m_curg(AX), AX
 	MOVQ	(g_stack+stack_hi)(AX), AX
 	RET
+
+// The top-most function running on a goroutine
+// returns to goexit+PCQuantum.
+TEXT runtime·goexit(SB),NOSPLIT,$0-0
+	BYTE	$0x90	// NOP
+	CALL	runtime·goexit1(SB)	// does not return

src/runtime/asm_amd64p32.s

@@ -1079,3 +1079,9 @@ TEXT runtime·fastrand1(SB), NOSPLIT, $0-4
 TEXT runtime·return0(SB), NOSPLIT, $0
 	MOVL	$0, AX
 	RET
+
+// The top-most function running on a goroutine
+// returns to goexit+PCQuantum.
+TEXT runtime·goexit(SB),NOSPLIT,$0-0
+	BYTE	$0x90	// NOP
+	CALL	runtime·goexit1(SB)	// does not return

src/runtime/asm_arm.s

@@ -1320,3 +1320,9 @@ TEXT _cgo_topofstack(SB),NOSPLIT,$8
 	MOVW	saveG-8(SP), g
 	MOVW	saveR11-4(SP), R11
 	RET
+
+// The top-most function running on a goroutine
+// returns to goexit+PCQuantum.
+TEXT runtime·goexit(SB),NOSPLIT,$-4-0
+	MOVW	R0, R0	// NOP
+	BL	runtime·goexit1(SB)	// does not return

src/runtime/asm_power64x.s

@@ -980,3 +980,9 @@ TEXT runtime·return0(SB), NOSPLIT, $0
 // Must obey the gcc calling convention.
 TEXT _cgo_topofstack(SB),NOSPLIT,$0
 	MOVD	R0, 26(R0)
+
+// The top-most function running on a goroutine
+// returns to goexit+PCQuantum.
+TEXT runtime·goexit(SB),NOSPLIT,$-8-0
+	MOVD	R0, R0	// NOP
+	BL	runtime·goexit1(SB)	// does not return

src/runtime/crash_cgo_test.go

@@ -36,10 +36,14 @@ func TestCgoTraceback(t *testing.T) {
 }
 
 func TestCgoExternalThreadPanic(t *testing.T) {
-	if runtime.GOOS == "windows" || runtime.GOOS == "plan9" {
+	if runtime.GOOS == "plan9" {
 		t.Skipf("no pthreads on %s", runtime.GOOS)
 	}
-	got := executeTest(t, cgoExternalThreadPanicSource, nil, "main.c", cgoExternalThreadPanicC)
+	csrc := cgoExternalThreadPanicC
+	if runtime.GOOS == "windows" {
+		csrc = cgoExternalThreadPanicC_windows
+	}
+	got := executeTest(t, cgoExternalThreadPanicSource, nil, "main.c", csrc)
 	want := "panic: BOOM"
 	if !strings.Contains(got, want) {
 		t.Fatalf("want failure containing %q. output:\n%s\n", want, got)
@@ -169,3 +173,24 @@ start(void)
 		printf("pthread_create failed\n");
 }
 `
+
+const cgoExternalThreadPanicC_windows = `
+#include <stdlib.h>
+#include <stdio.h>
+
+void gopanic(void);
+
+static void*
+die(void* x)
+{
+	gopanic();
+	return 0;
+}
+
+void
+start(void)
+{
+	if(_beginthreadex(0, 0, die, 0, 0, 0) != 0)
+		printf("_beginthreadex failed\n");
+}
+`

src/runtime/extern.go

@@ -117,11 +117,20 @@ func Caller(skip int) (pc uintptr, file string, line int, ok bool) {
 	return
 }
 
-// Callers fills the slice pc with the program counters of function invocations
+// Callers fills the slice pc with the return program counters of function invocations
 // on the calling goroutine's stack.  The argument skip is the number of stack frames
 // to skip before recording in pc, with 0 identifying the frame for Callers itself and
 // 1 identifying the caller of Callers.
 // It returns the number of entries written to pc.
+//
+// Note that since each slice entry pc[i] is a return program counter,
+// looking up the file and line for pc[i] (for example, using (*Func).FileLine)
+// will return the file and line number of the instruction immediately
+// following the call.
+// To look up the file and line number of the call itself, use pc[i]-1.
+// As an exception to this rule, if pc[i-1] corresponds to the function
+// runtime.sigpanic, then pc[i] is the program counter of a faulting
+// instruction and should be used without any subtraction.
 func Callers(skip int, pc []uintptr) int {
 	// runtime.callers uses pc.array==nil as a signal
 	// to print a stack trace.  Pick off 0-length pc here

src/runtime/heapdump.c

@@ -413,7 +413,7 @@ dumpgoroutine(G *gp)
 	child.sp = nil;
 	child.depth = 0;
 	fn = dumpframe;
-	runtime·gentraceback(pc, sp, lr, gp, 0, nil, 0x7fffffff, &fn, &child, false);
+	runtime·gentraceback(pc, sp, lr, gp, 0, nil, 0x7fffffff, &fn, &child, 0);
 
 	// dump defer & panic records
 	for(d = gp->defer; d != nil; d = d->link) {

src/runtime/mgc0.c

@@ -774,7 +774,7 @@ scanstack(G *gp)
 		runtime·throw("can't scan gchelper stack");
 
 	fn = scanframe;
-	runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, 0, nil, 0x7fffffff, &fn, nil, false);
+	runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, 0, nil, 0x7fffffff, &fn, nil, 0);
 	runtime·tracebackdefers(gp, &fn, nil);
 }
 
@@ -1966,7 +1966,7 @@ runtime·getgcmask(byte *p, Type *t, byte **mask, uintptr *len)
 	frame.fn = nil;
 	frame.sp = (uintptr)p;
 	cb = getgcmaskcb;
-	runtime·gentraceback(g->m->curg->sched.pc, g->m->curg->sched.sp, 0, g->m->curg, 0, nil, 1000, &cb, &frame, false);
+	runtime·gentraceback(g->m->curg->sched.pc, g->m->curg->sched.sp, 0, g->m->curg, 0, nil, 1000, &cb, &frame, 0);
 	if(frame.fn != nil) {
 		Func *f;
 		StackMap *stackmap;

src/runtime/mprof.go

@@ -562,7 +562,7 @@ func GoroutineProfile(p []StackRecord) (n int, ok bool) {
 }
 
 func saveg(pc, sp uintptr, gp *g, r *StackRecord) {
-	n := gentraceback(pc, sp, 0, gp, 0, &r.Stack0[0], len(r.Stack0), nil, nil, false)
+	n := gentraceback(pc, sp, 0, gp, 0, &r.Stack0[0], len(r.Stack0), nil, nil, 0)
 	if n < len(r.Stack0) {
 		r.Stack0[n] = 0
 	}

src/runtime/os_plan9_386.c

@@ -114,7 +114,7 @@ Throw:
 
 	if(runtime·gotraceback(&crash)) {
 		runtime·goroutineheader(gp);
-		runtime·traceback(ureg->pc, ureg->sp, 0, gp);
+		runtime·tracebacktrap(ureg->pc, ureg->sp, 0, gp);
 		runtime·tracebackothers(gp);
 		runtime·printf("\n");
 		runtime·dumpregs(ureg);

src/runtime/os_plan9_amd64.c

@@ -122,7 +122,7 @@ Throw:
 
 	if(runtime·gotraceback(&crash)) {
 		runtime·goroutineheader(gp);
-		runtime·traceback(ureg->ip, ureg->sp, 0, gp);
+		runtime·tracebacktrap(ureg->ip, ureg->sp, 0, gp);
 		runtime·tracebackothers(gp);
 		runtime·printf("\n");
 		runtime·dumpregs(ureg);

src/runtime/os_windows_386.c

@@ -97,7 +97,7 @@ runtime·lastcontinuehandler(ExceptionRecord *info, Context *r, G *gp)
 	runtime·printf("\n");
 
 	if(runtime·gotraceback(&crash)){
-		runtime·traceback(r->Eip, r->Esp, 0, gp);
+		runtime·tracebacktrap(r->Eip, r->Esp, 0, gp);
 		runtime·tracebackothers(gp);
 		runtime·dumpregs(r);
 	}

src/runtime/os_windows_amd64.c

@@ -119,7 +119,7 @@ runtime·lastcontinuehandler(ExceptionRecord *info, Context *r, G *gp)
 	runtime·printf("\n");
 
 	if(runtime·gotraceback(&crash)){
-		runtime·traceback(r->Rip, r->Rsp, 0, gp);
+		runtime·tracebacktrap(r->Rip, r->Rsp, 0, gp);
 		runtime·tracebackothers(gp);
 		runtime·dumpregs(r);
 	}

src/runtime/proc.c

@@ -1643,12 +1643,10 @@ runtime·gosched_m(G *gp)
 }
 
 // Finishes execution of the current goroutine.
-// Need to mark it as nosplit, because it runs with sp > stackbase.
-// Since it does not return it does not matter.  But if it is preempted
-// at the split stack check, GC will complain about inconsistent sp.
+// Must be NOSPLIT because it is called from Go.
 #pragma textflag NOSPLIT
 void
-runtime·goexit(void)
+runtime·goexit1(void)
 {
 	void (*fn)(G*);
 
@@ -2192,7 +2190,7 @@ runtime·newproc1(FuncVal *fn, byte *argp, int32 narg, int32 nret, void *callerp
 
 	runtime·memclr((byte*)&newg->sched, sizeof newg->sched);
 	newg->sched.sp = (uintptr)sp;
-	newg->sched.pc = (uintptr)runtime·goexit;
+	newg->sched.pc = (uintptr)runtime·goexit + PCQuantum; // +PCQuantum so that previous instruction is in same function
 	newg->sched.g = newg;
 	runtime·gostartcallfn(&newg->sched, fn);
 	newg->gopc = (uintptr)callerpc;
@@ -2532,7 +2530,7 @@ runtime·sigprof(uint8 *pc, uint8 *sp, uint8 *lr, G *gp, M *mp)
 
 	n = 0;
 	if(traceback)
-		n = runtime·gentraceback((uintptr)pc, (uintptr)sp, (uintptr)lr, gp, 0, stk, nelem(stk), nil, nil, false);
+		n = runtime·gentraceback((uintptr)pc, (uintptr)sp, (uintptr)lr, gp, 0, stk, nelem(stk), nil, nil, TraceTrap);
 	if(!traceback || n <= 0) {
 		// Normal traceback is impossible or has failed.
 		// See if it falls into several common cases.
@@ -2542,13 +2540,13 @@ runtime·sigprof(uint8 *pc, uint8 *sp, uint8 *lr, G *gp, M *mp)
 			// Cgo, we can't unwind and symbolize arbitrary C code,
 			// so instead collect Go stack that leads to the cgo call.
 			// This is especially important on windows, since all syscalls are cgo calls.
-			n = runtime·gentraceback(mp->curg->syscallpc, mp->curg->syscallsp, 0, mp->curg, 0, stk, nelem(stk), nil, nil, false);
+			n = runtime·gentraceback(mp->curg->syscallpc, mp->curg->syscallsp, 0, mp->curg, 0, stk, nelem(stk), nil, nil, 0);
 		}
 #ifdef GOOS_windows
 		if(n == 0 && mp->libcallg != nil && mp->libcallpc != 0 && mp->libcallsp != 0) {
 			// Libcall, i.e. runtime syscall on windows.
 			// Collect Go stack that leads to the call.
-			n = runtime·gentraceback(mp->libcallpc, mp->libcallsp, 0, mp->libcallg, 0, stk, nelem(stk), nil, nil, false);
+			n = runtime·gentraceback(mp->libcallpc, mp->libcallsp, 0, mp->libcallg, 0, stk, nelem(stk), nil, nil, 0);
 		}
 #endif
 		if(n == 0) {

src/runtime/runtime.h

@@ -719,9 +719,15 @@ struct Stkframe
 	BitVector*	argmap;	// force use of this argmap
 };
 
-intgo	runtime·gentraceback(uintptr, uintptr, uintptr, G*, intgo, uintptr*, intgo, bool(**)(Stkframe*, void*), void*, bool);
+enum
+{
+	TraceRuntimeFrames = 1<<0, // include frames for internal runtime functions.
+	TraceTrap = 1<<1, // the initial PC, SP are from a trap, not a return PC from a call
+};
+intgo	runtime·gentraceback(uintptr, uintptr, uintptr, G*, intgo, uintptr*, intgo, bool(**)(Stkframe*, void*), void*, uintgo);
 void	runtime·tracebackdefers(G*, bool(**)(Stkframe*, void*), void*);
 void	runtime·traceback(uintptr pc, uintptr sp, uintptr lr, G* gp);
+void	runtime·tracebacktrap(uintptr pc, uintptr sp, uintptr lr, G* gp);
 void	runtime·tracebackothers(G*);
 bool	runtime·haszeroargs(uintptr pc);
 bool	runtime·topofstack(Func*);

src/runtime/signal_386.c

@@ -109,7 +109,7 @@ runtime·sighandler(int32 sig, Siginfo *info, void *ctxt, G *gp)
 
 	if(runtime·gotraceback(&crash)){
 		runtime·goroutineheader(gp);
-		runtime·traceback(SIG_EIP(info, ctxt), SIG_ESP(info, ctxt), 0, gp);
+		runtime·tracebacktrap(SIG_EIP(info, ctxt), SIG_ESP(info, ctxt), 0, gp);
 		runtime·tracebackothers(gp);
 		runtime·printf("\n");
 		runtime·dumpregs(info, ctxt);

src/runtime/signal_amd64x.c

@@ -143,7 +143,7 @@ runtime·sighandler(int32 sig, Siginfo *info, void *ctxt, G *gp)
 
 	if(runtime·gotraceback(&crash)){
 		runtime·goroutineheader(gp);
-		runtime·traceback(SIG_RIP(info, ctxt), SIG_RSP(info, ctxt), 0, gp);
+		runtime·tracebacktrap(SIG_RIP(info, ctxt), SIG_RSP(info, ctxt), 0, gp);
 		runtime·tracebackothers(gp);
 		runtime·printf("\n");
 		runtime·dumpregs(info, ctxt);

src/runtime/signal_arm.c

@@ -108,7 +108,7 @@ runtime·sighandler(int32 sig, Siginfo *info, void *ctxt, G *gp)
 
 	if(runtime·gotraceback(&crash)){
 		runtime·goroutineheader(gp);
-		runtime·traceback(SIG_PC(info, ctxt), SIG_SP(info, ctxt), SIG_LR(info, ctxt), gp);
+		runtime·tracebacktrap(SIG_PC(info, ctxt), SIG_SP(info, ctxt), SIG_LR(info, ctxt), gp);
 		runtime·tracebackothers(gp);
 		runtime·printf("\n");
 		runtime·dumpregs(info, ctxt);

src/runtime/signal_power64x.c

@@ -124,7 +124,7 @@ runtime·sighandler(int32 sig, Siginfo *info, void *ctxt, G *gp)
 
 	if(runtime·gotraceback(&crash)){
 		runtime·goroutineheader(gp);
-		runtime·traceback(SIG_PC(info, ctxt), SIG_SP(info, ctxt), SIG_LINK(info, ctxt), gp);
+		runtime·tracebacktrap(SIG_PC(info, ctxt), SIG_SP(info, ctxt), SIG_LINK(info, ctxt), gp);
 		runtime·tracebackothers(gp);
 		runtime·printf("\n");
 		runtime·dumpregs(info, ctxt);

src/runtime/stack.c

@@ -620,7 +620,7 @@ copystack(G *gp, uintptr newsize)
 	adjinfo.old = old;
 	adjinfo.delta = new.hi - old.hi;
 	cb = adjustframe;
-	runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, 0, nil, 0x7fffffff, &cb, &adjinfo, false);
+	runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, 0, nil, 0x7fffffff, &cb, &adjinfo, 0);
 	
 	// adjust other miscellaneous things that have pointers into stacks.
 	adjustctxt(gp, &adjinfo);

src/runtime/traceback.go

@@ -96,7 +96,7 @@ func tracebackdefers(gp *g, callback func(*stkframe, unsafe.Pointer) bool, v uns
 // the runtime.Callers function (pcbuf != nil), as well as the garbage
 // collector (callback != nil).  A little clunky to merge these, but avoids
 // duplicating the code and all its subtlety.
-func gentraceback(pc0 uintptr, sp0 uintptr, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max int, callback func(*stkframe, unsafe.Pointer) bool, v unsafe.Pointer, printall bool) int {
+func gentraceback(pc0 uintptr, sp0 uintptr, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max int, callback func(*stkframe, unsafe.Pointer) bool, v unsafe.Pointer, flags uint) int {
 	if goexitPC == 0 {
 		gothrow("gentraceback before goexitPC initialization")
 	}
@@ -297,13 +297,13 @@ func gentraceback(pc0 uintptr, sp0 uintptr, lr0 uintptr, gp *g, skip int, pcbuf
 			}
 		}
 		if printing {
-			if printall || showframe(f, gp) {
+			if (flags&_TraceRuntimeFrames) != 0 || showframe(f, gp) {
 				// Print during crash.
 				//	main(0x1, 0x2, 0x3)
 				//		/home/rsc/go/src/runtime/x.go:23 +0xf
 				//
 				tracepc := frame.pc // back up to CALL instruction for funcline.
-				if n > 0 && frame.pc > f.entry && !waspanic {
+				if (n > 0 || flags&_TraceTrap == 0) && frame.pc > f.entry && !waspanic {
 					tracepc--
 				}
 				print(gofuncname(f), "(")
@@ -475,17 +475,32 @@ func printcreatedby(gp *g) {
 }
 
 func traceback(pc uintptr, sp uintptr, lr uintptr, gp *g) {
+	traceback1(pc, sp, lr, gp, 0)
+}
+
+// tracebacktrap is like traceback but expects that the PC and SP were obtained
+// from a trap, not from gp->sched or gp->syscallpc/gp->syscallsp or getcallerpc/getcallersp.
+// Because they are from a trap instead of from a saved pair,
+// the initial PC must not be rewound to the previous instruction.
+// (All the saved pairs record a PC that is a return address, so we
+// rewind it into the CALL instruction.)
+func tracebacktrap(pc uintptr, sp uintptr, lr uintptr, gp *g) {
+	traceback1(pc, sp, lr, gp, _TraceTrap)
+}
+
+func traceback1(pc uintptr, sp uintptr, lr uintptr, gp *g, flags uint) {
 	var n int
 	if readgstatus(gp)&^_Gscan == _Gsyscall {
-		// Override signal registers if blocked in system call.
+		// Override registers if blocked in system call.
 		pc = gp.syscallpc
 		sp = gp.syscallsp
+		flags &^= _TraceTrap
 	}
 	// Print traceback. By default, omits runtime frames.
 	// If that means we print nothing at all, repeat forcing all frames printed.
-	n = gentraceback(pc, sp, lr, gp, 0, nil, _TracebackMaxFrames, nil, nil, false)
-	if n == 0 {
-		n = gentraceback(pc, sp, lr, gp, 0, nil, _TracebackMaxFrames, nil, nil, true)
+	n = gentraceback(pc, sp, lr, gp, 0, nil, _TracebackMaxFrames, nil, nil, flags)
+	if n == 0 && (flags&_TraceRuntimeFrames) == 0 {
+		n = gentraceback(pc, sp, lr, gp, 0, nil, _TracebackMaxFrames, nil, nil, flags|_TraceRuntimeFrames)
 	}
 	if n == _TracebackMaxFrames {
 		print("...additional frames elided...\n")
@@ -496,11 +511,11 @@ func traceback(pc uintptr, sp uintptr, lr uintptr, gp *g) {
 func callers(skip int, pcbuf *uintptr, m int) int {
 	sp := getcallersp(unsafe.Pointer(&skip))
 	pc := uintptr(getcallerpc(unsafe.Pointer(&skip)))
-	return gentraceback(pc, sp, 0, getg(), skip, pcbuf, m, nil, nil, false)
+	return gentraceback(pc, sp, 0, getg(), skip, pcbuf, m, nil, nil, 0)
 }
 
 func gcallers(gp *g, skip int, pcbuf *uintptr, m int) int {
-	return gentraceback(^uintptr(0), ^uintptr(0), 0, gp, skip, pcbuf, m, nil, nil, false)
+	return gentraceback(^uintptr(0), ^uintptr(0), 0, gp, skip, pcbuf, m, nil, nil, 0)
 }
 
 func showframe(f *_func, gp *g) bool {

src/sync/atomic/value.go

@@ -38,7 +38,7 @@ func (v *Value) Load() (x interface{}) {
 	return
 }
 
-// Store sets the value of the Value to v.
+// Store sets the value of the Value to x.
 // All calls to Store for a given Value must use values of the same concrete type.
 // Store of an inconsistent type panics, as does Store(nil).
 func (v *Value) Store(x interface{}) {

test/fixedbugs/issue7690.go

+// run
+
+// Copyright 2014 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// issue 7690 - Stack and other routines did not back up initial PC
+// into CALL instruction, instead reporting line number of next instruction,
+// which might be on a different line.
+
+package main
+
+import (
+	"bytes"
+	"regexp"
+	"runtime"
+	"strconv"
+)
+
+func main() {
+	buf1 := make([]byte, 1000)
+	buf2 := make([]byte, 1000)
+
+	runtime.Stack(buf1, false)      // CALL is last instruction on this line
+	n := runtime.Stack(buf2, false) // CALL is followed by load of result from stack
+
+	buf1 = buf1[:bytes.IndexByte(buf1, 0)]
+	buf2 = buf2[:n]
+
+	re := regexp.MustCompile(`(?m)^main\.main\(\)\n.*/issue7690.go:([0-9]+)`)
+	m1 := re.FindStringSubmatch(string(buf1))
+	if m1 == nil {
+		println("BUG: cannot find main.main in first trace")
+		return
+	}
+	m2 := re.FindStringSubmatch(string(buf2))
+	if m2 == nil {
+		println("BUG: cannot find main.main in second trace")
+		return
+	}
+
+	n1, _ := strconv.Atoi(m1[1])
+	n2, _ := strconv.Atoi(m2[1])
+	if n1+1 != n2 {
+		println("BUG: expect runtime.Stack on back to back lines, have", n1, n2)
+		println(string(buf1))
+		println(string(buf2))
+	}
+}