2 files changed, 646 insertions, 0 deletions
diff --git a/vendor/github.com/twitchyliquid64/golang-asm/src/pos.go b/vendor/github.com/twitchyliquid64/golang-asm/src/pos.go
new file mode 100644
index 000000000..b6816a56e
--- /dev/null
+++ b/vendor/github.com/twitchyliquid64/golang-asm/src/pos.go
@@ -0,0 +1,470 @@
+// Copyright 2016 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.
+
+// This file implements the encoding of source positions.
+
+package src
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+)
+
+// A Pos encodes a source position consisting of a (line, column) number pair
+// and a position base. A zero Pos is a ready to use "unknown" position (nil
+// position base and zero line number).
+//
+// The (line, column) values refer to a position in a file independent of any
+// position base ("absolute" file position).
+//
+// The position base is used to determine the "relative" position, that is the
+// filename and line number relative to the position base. If the base refers
+// to the current file, there is no difference between absolute and relative
+// positions. If it refers to a //line directive, a relative position is relative
+// to that directive. A position base in turn contains the position at which it
+// was introduced in the current file.
+type Pos struct {
+	base *PosBase
+	lico
+}
+
+// NoPos is a valid unknown position.
+var NoPos Pos
+
+// MakePos creates a new Pos value with the given base, and (file-absolute)
+// line and column.
+func MakePos(base *PosBase, line, col uint) Pos {
+	return Pos{base, makeLico(line, col)}
+}
+
+// IsKnown reports whether the position p is known.
+// A position is known if it either has a non-nil
+// position base, or a non-zero line number.
+func (p Pos) IsKnown() bool {
+	return p.base != nil || p.Line() != 0
+}
+
+// Before reports whether the position p comes before q in the source.
+// For positions in different files, ordering is by filename.
+func (p Pos) Before(q Pos) bool {
+	n, m := p.Filename(), q.Filename()
+	return n < m || n == m && p.lico < q.lico
+}
+
+// After reports whether the position p comes after q in the source.
+// For positions in different files, ordering is by filename.
+func (p Pos) After(q Pos) bool {
+	n, m := p.Filename(), q.Filename()
+	return n > m || n == m && p.lico > q.lico
+}
+
+func (p Pos) LineNumber() string {
+	if !p.IsKnown() {
+		return "?"
+	}
+	return p.lico.lineNumber()
+}
+
+func (p Pos) LineNumberHTML() string {
+	if !p.IsKnown() {
+		return "?"
+	}
+	return p.lico.lineNumberHTML()
+}
+
+// Filename returns the name of the actual file containing this position.
+func (p Pos) Filename() string { return p.base.Pos().RelFilename() }
+
+// Base returns the position base.
+func (p Pos) Base() *PosBase { return p.base }
+
+// SetBase sets the position base.
+func (p *Pos) SetBase(base *PosBase) { p.base = base }
+
+// RelFilename returns the filename recorded with the position's base.
+func (p Pos) RelFilename() string { return p.base.Filename() }
+
+// RelLine returns the line number relative to the position's base.
+func (p Pos) RelLine() uint {
+	b := p.base
+	if b.Line() == 0 {
+		// base line is unknown => relative line is unknown
+		return 0
+	}
+	return b.Line() + (p.Line() - b.Pos().Line())
+}
+
+// RelCol returns the column number relative to the position's base.
+func (p Pos) RelCol() uint {
+	b := p.base
+	if b.Col() == 0 {
+		// base column is unknown => relative column is unknown
+		// (the current specification for line directives requires
+		// this to apply until the next PosBase/line directive,
+		// not just until the new newline)
+		return 0
+	}
+	if p.Line() == b.Pos().Line() {
+		// p on same line as p's base => column is relative to p's base
+		return b.Col() + (p.Col() - b.Pos().Col())
+	}
+	return p.Col()
+}
+
+// AbsFilename() returns the absolute filename recorded with the position's base.
+func (p Pos) AbsFilename() string { return p.base.AbsFilename() }
+
+// SymFilename() returns the absolute filename recorded with the position's base,
+// prefixed by FileSymPrefix to make it appropriate for use as a linker symbol.
+func (p Pos) SymFilename() string { return p.base.SymFilename() }
+
+func (p Pos) String() string {
+	return p.Format(true, true)
+}
+
+// Format formats a position as "filename:line" or "filename:line:column",
+// controlled by the showCol flag and if the column is known (!= 0).
+// For positions relative to line directives, the original position is
+// shown as well, as in "filename:line[origfile:origline:origcolumn] if
+// showOrig is set.
+func (p Pos) Format(showCol, showOrig bool) string {
+	buf := new(bytes.Buffer)
+	p.WriteTo(buf, showCol, showOrig)
+	return buf.String()
+}
+
+// WriteTo a position to w, formatted as Format does.
+func (p Pos) WriteTo(w io.Writer, showCol, showOrig bool) {
+	if !p.IsKnown() {
+		io.WriteString(w, "<unknown line number>")
+		return
+	}
+
+	if b := p.base; b == b.Pos().base {
+		// base is file base (incl. nil)
+		format(w, p.Filename(), p.Line(), p.Col(), showCol)
+		return
+	}
+
+	// base is relative
+	// Print the column only for the original position since the
+	// relative position's column information may be bogus (it's
+	// typically generated code and we can't say much about the
+	// original source at that point but for the file:line info
+	// that's provided via a line directive).
+	// TODO(gri) This may not be true if we have an inlining base.
+	// We may want to differentiate at some point.
+	format(w, p.RelFilename(), p.RelLine(), p.RelCol(), showCol)
+	if showOrig {
+		io.WriteString(w, "[")
+		format(w, p.Filename(), p.Line(), p.Col(), showCol)
+		io.WriteString(w, "]")
+	}
+}
+
+// format formats a (filename, line, col) tuple as "filename:line" (showCol
+// is false or col == 0) or "filename:line:column" (showCol is true and col != 0).
+func format(w io.Writer, filename string, line, col uint, showCol bool) {
+	io.WriteString(w, filename)
+	io.WriteString(w, ":")
+	fmt.Fprint(w, line)
+	// col == 0 and col == colMax are interpreted as unknown column values
+	if showCol && 0 < col && col < colMax {
+		io.WriteString(w, ":")
+		fmt.Fprint(w, col)
+	}
+}
+
+// formatstr wraps format to return a string.
+func formatstr(filename string, line, col uint, showCol bool) string {
+	buf := new(bytes.Buffer)
+	format(buf, filename, line, col, showCol)
+	return buf.String()
+}
+
+// ----------------------------------------------------------------------------
+// PosBase
+
+// A PosBase encodes a filename and base position.
+// Typically, each file and line directive introduce a PosBase.
+type PosBase struct {
+	pos         Pos    // position at which the relative position is (line, col)
+	filename    string // file name used to open source file, for error messages
+	absFilename string // absolute file name, for PC-Line tables
+	symFilename string // cached symbol file name, to avoid repeated string concatenation
+	line, col   uint   // relative line, column number at pos
+	inl         int    // inlining index (see cmd/internal/obj/inl.go)
+}
+
+// NewFileBase returns a new *PosBase for a file with the given (relative and
+// absolute) filenames.
+func NewFileBase(filename, absFilename string) *PosBase {
+	base := &PosBase{
+		filename:    filename,
+		absFilename: absFilename,
+		symFilename: FileSymPrefix + absFilename,
+		line:        1,
+		col:         1,
+		inl:         -1,
+	}
+	base.pos = MakePos(base, 1, 1)
+	return base
+}
+
+// NewLinePragmaBase returns a new *PosBase for a line directive of the form
+//      //line filename:line:col
+//      /*line filename:line:col*/
+// at position pos.
+func NewLinePragmaBase(pos Pos, filename, absFilename string, line, col uint) *PosBase {
+	return &PosBase{pos, filename, absFilename, FileSymPrefix + absFilename, line, col, -1}
+}
+
+// NewInliningBase returns a copy of the old PosBase with the given inlining
+// index. If old == nil, the resulting PosBase has no filename.
+func NewInliningBase(old *PosBase, inlTreeIndex int) *PosBase {
+	if old == nil {
+		base := &PosBase{line: 1, col: 1, inl: inlTreeIndex}
+		base.pos = MakePos(base, 1, 1)
+		return base
+	}
+	copy := *old
+	base := &copy
+	base.inl = inlTreeIndex
+	if old == old.pos.base {
+		base.pos.base = base
+	}
+	return base
+}
+
+var noPos Pos
+
+// Pos returns the position at which base is located.
+// If b == nil, the result is the zero position.
+func (b *PosBase) Pos() *Pos {
+	if b != nil {
+		return &b.pos
+	}
+	return &noPos
+}
+
+// Filename returns the filename recorded with the base.
+// If b == nil, the result is the empty string.
+func (b *PosBase) Filename() string {
+	if b != nil {
+		return b.filename
+	}
+	return ""
+}
+
+// AbsFilename returns the absolute filename recorded with the base.
+// If b == nil, the result is the empty string.
+func (b *PosBase) AbsFilename() string {
+	if b != nil {
+		return b.absFilename
+	}
+	return ""
+}
+
+const FileSymPrefix = "gofile.."
+
+// SymFilename returns the absolute filename recorded with the base,
+// prefixed by FileSymPrefix to make it appropriate for use as a linker symbol.
+// If b is nil, SymFilename returns FileSymPrefix + "??".
+func (b *PosBase) SymFilename() string {
+	if b != nil {
+		return b.symFilename
+	}
+	return FileSymPrefix + "??"
+}
+
+// Line returns the line number recorded with the base.
+// If b == nil, the result is 0.
+func (b *PosBase) Line() uint {
+	if b != nil {
+		return b.line
+	}
+	return 0
+}
+
+// Col returns the column number recorded with the base.
+// If b == nil, the result is 0.
+func (b *PosBase) Col() uint {
+	if b != nil {
+		return b.col
+	}
+	return 0
+}
+
+// InliningIndex returns the index into the global inlining
+// tree recorded with the base. If b == nil or the base has
+// not been inlined, the result is < 0.
+func (b *PosBase) InliningIndex() int {
+	if b != nil {
+		return b.inl
+	}
+	return -1
+}
+
+// ----------------------------------------------------------------------------
+// lico
+
+// A lico is a compact encoding of a LIne and COlumn number.
+type lico uint32
+
+// Layout constants: 20 bits for line, 8 bits for column, 2 for isStmt, 2 for pro/epilogue
+// (If this is too tight, we can either make lico 64b wide,
+// or we can introduce a tiered encoding where we remove column
+// information as line numbers grow bigger; similar to what gcc
+// does.)
+// The bitfield order is chosen to make IsStmt be the least significant
+// part of a position; its use is to communicate statement edges through
+// instruction scrambling in code generation, not to impose an order.
+// TODO: Prologue and epilogue are perhaps better handled as pseudo-ops for the assembler,
+// because they have almost no interaction with other uses of the position.
+const (
+	lineBits, lineMax     = 20, 1<<lineBits - 2
+	bogusLine             = 1 // Used to disrupt infinite loops to prevent debugger looping
+	isStmtBits, isStmtMax = 2, 1<<isStmtBits - 1
+	xlogueBits, xlogueMax = 2, 1<<xlogueBits - 1
+	colBits, colMax       = 32 - lineBits - xlogueBits - isStmtBits, 1<<colBits - 1
+
+	isStmtShift = 0
+	isStmtMask  = isStmtMax << isStmtShift
+	xlogueShift = isStmtBits + isStmtShift
+	xlogueMask  = xlogueMax << xlogueShift
+	colShift    = xlogueBits + xlogueShift
+	lineShift   = colBits + colShift
+)
+const (
+	// It is expected that the front end or a phase in SSA will usually generate positions tagged with
+	// PosDefaultStmt, but note statement boundaries with PosIsStmt.  Simple statements will have a single
+	// boundary; for loops with initialization may have one for their entry and one for their back edge
+	// (this depends on exactly how the loop is compiled; the intent is to provide a good experience to a
+	// user debugging a program; the goal is that a breakpoint set on the loop line fires both on entry
+	// and on iteration).  Proper treatment of non-gofmt input with multiple simple statements on a single
+	// line is TBD.
+	//
+	// Optimizing compilation will move instructions around, and some of these will become known-bad as
+	// step targets for debugging purposes (examples: register spills and reloads; code generated into
+	// the entry block; invariant code hoisted out of loops) but those instructions will still have interesting
+	// positions for profiling purposes. To reflect this these positions will be changed to PosNotStmt.
+	//
+	// When the optimizer removes an instruction marked PosIsStmt; it should attempt to find a nearby
+	// instruction with the same line marked PosDefaultStmt to be the new statement boundary.  I.e., the
+	// optimizer should make a best-effort to conserve statement boundary positions, and might be enhanced
+	// to note when a statement boundary is not conserved.
+	//
+	// Code cloning, e.g. loop unrolling or loop unswitching, is an exception to the conservation rule
+	// because a user running a debugger would expect to see breakpoints active in the copies of the code.
+	//
+	// In non-optimizing compilation there is still a role for PosNotStmt because of code generation
+	// into the entry block.  PosIsStmt statement positions should be conserved.
+	//
+	// When code generation occurs any remaining default-marked positions are replaced with not-statement
+	// positions.
+	//
+	PosDefaultStmt uint = iota // Default; position is not a statement boundary, but might be if optimization removes the designated statement boundary
+	PosIsStmt                  // Position is a statement boundary; if optimization removes the corresponding instruction, it should attempt to find a new instruction to be the boundary.
+	PosNotStmt                 // Position should not be a statement boundary, but line should be preserved for profiling and low-level debugging purposes.
+)
+
+type PosXlogue uint
+
+const (
+	PosDefaultLogue PosXlogue = iota
+	PosPrologueEnd
+	PosEpilogueBegin
+)
+
+func makeLicoRaw(line, col uint) lico {
+	return lico(line<<lineShift | col<<colShift)
+}
+
+// This is a not-position that will not be elided.
+// Depending on the debugger (gdb or delve) it may or may not be displayed.
+func makeBogusLico() lico {
+	return makeLicoRaw(bogusLine, 0).withIsStmt()
+}
+
+func makeLico(line, col uint) lico {
+	if line > lineMax {
+		// cannot represent line, use max. line so we have some information
+		line = lineMax
+	}
+	if col > colMax {
+		// cannot represent column, use max. column so we have some information
+		col = colMax
+	}
+	// default is not-sure-if-statement
+	return makeLicoRaw(line, col)
+}
+
+func (x lico) Line() uint           { return uint(x) >> lineShift }
+func (x lico) SameLine(y lico) bool { return 0 == (x^y)&^lico(1<<lineShift-1) }
+func (x lico) Col() uint            { return uint(x) >> colShift & colMax }
+func (x lico) IsStmt() uint {
+	if x == 0 {
+		return PosNotStmt
+	}
+	return uint(x) >> isStmtShift & isStmtMax
+}
+func (x lico) Xlogue() PosXlogue {
+	return PosXlogue(uint(x) >> xlogueShift & xlogueMax)
+}
+
+// withNotStmt returns a lico for the same location, but not a statement
+func (x lico) withNotStmt() lico {
+	return x.withStmt(PosNotStmt)
+}
+
+// withDefaultStmt returns a lico for the same location, with default isStmt
+func (x lico) withDefaultStmt() lico {
+	return x.withStmt(PosDefaultStmt)
+}
+
+// withIsStmt returns a lico for the same location, tagged as definitely a statement
+func (x lico) withIsStmt() lico {
+	return x.withStmt(PosIsStmt)
+}
+
+// withLogue attaches a prologue/epilogue attribute to a lico
+func (x lico) withXlogue(xlogue PosXlogue) lico {
+	if x == 0 {
+		if xlogue == 0 {
+			return x
+		}
+		// Normalize 0 to "not a statement"
+		x = lico(PosNotStmt << isStmtShift)
+	}
+	return lico(uint(x) & ^uint(xlogueMax<<xlogueShift) | (uint(xlogue) << xlogueShift))
+}
+
+// withStmt returns a lico for the same location with specified is_stmt attribute
+func (x lico) withStmt(stmt uint) lico {
+	if x == 0 {
+		return lico(0)
+	}
+	return lico(uint(x) & ^uint(isStmtMax<<isStmtShift) | (stmt << isStmtShift))
+}
+
+func (x lico) lineNumber() string {
+	return fmt.Sprintf("%d", x.Line())
+}
+
+func (x lico) lineNumberHTML() string {
+	if x.IsStmt() == PosDefaultStmt {
+		return fmt.Sprintf("%d", x.Line())
+	}
+	style, pfx := "b", "+"
+	if x.IsStmt() == PosNotStmt {
+		style = "s" // /strike not supported in HTML5
+		pfx = ""
+	}
+	return fmt.Sprintf("<%s>%s%d</%s>", style, pfx, x.Line(), style)
+}
+
+func (x lico) atColumn1() lico {
+	return makeLico(x.Line(), 1).withIsStmt()
+}
diff --git a/vendor/github.com/twitchyliquid64/golang-asm/src/xpos.go b/vendor/github.com/twitchyliquid64/golang-asm/src/xpos.go
new file mode 100644
index 000000000..867d0ab06
--- /dev/null
+++ b/vendor/github.com/twitchyliquid64/golang-asm/src/xpos.go
@@ -0,0 +1,176 @@
+// Copyright 2016 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.
+
+// This file implements the compressed encoding of source
+// positions using a lookup table.
+
+package src
+
+// XPos is a more compact representation of Pos.
+type XPos struct {
+	index int32
+	lico
+}
+
+// NoXPos is a valid unknown position.
+var NoXPos XPos
+
+// IsKnown reports whether the position p is known.
+// XPos.IsKnown() matches Pos.IsKnown() for corresponding
+// positions.
+func (p XPos) IsKnown() bool {
+	return p.index != 0 || p.Line() != 0
+}
+
+// Before reports whether the position p comes before q in the source.
+// For positions with different bases, ordering is by base index.
+func (p XPos) Before(q XPos) bool {
+	n, m := p.index, q.index
+	return n < m || n == m && p.lico < q.lico
+}
+
+// SameFile reports whether p and q are positions in the same file.
+func (p XPos) SameFile(q XPos) bool {
+	return p.index == q.index
+}
+
+// SameFileAndLine reports whether p and q are positions on the same line in the same file.
+func (p XPos) SameFileAndLine(q XPos) bool {
+	return p.index == q.index && p.lico.SameLine(q.lico)
+}
+
+// After reports whether the position p comes after q in the source.
+// For positions with different bases, ordering is by base index.
+func (p XPos) After(q XPos) bool {
+	n, m := p.index, q.index
+	return n > m || n == m && p.lico > q.lico
+}
+
+// WithNotStmt returns the same location to be marked with DWARF is_stmt=0
+func (p XPos) WithNotStmt() XPos {
+	p.lico = p.lico.withNotStmt()
+	return p
+}
+
+// WithDefaultStmt returns the same location with undetermined is_stmt
+func (p XPos) WithDefaultStmt() XPos {
+	p.lico = p.lico.withDefaultStmt()
+	return p
+}
+
+// WithIsStmt returns the same location to be marked with DWARF is_stmt=1
+func (p XPos) WithIsStmt() XPos {
+	p.lico = p.lico.withIsStmt()
+	return p
+}
+
+// WithBogusLine returns a bogus line that won't match any recorded for the source code.
+// Its use is to disrupt the statements within an infinite loop so that the debugger
+// will not itself loop infinitely waiting for the line number to change.
+// gdb chooses not to display the bogus line; delve shows it with a complaint, but the
+// alternative behavior is to hang.
+func (p XPos) WithBogusLine() XPos {
+	if p.index == 0 {
+		// See #35652
+		panic("Assigning a bogus line to XPos with no file will cause mysterious downstream failures.")
+	}
+	p.lico = makeBogusLico()
+	return p
+}
+
+// WithXlogue returns the same location but marked with DWARF function prologue/epilogue
+func (p XPos) WithXlogue(x PosXlogue) XPos {
+	p.lico = p.lico.withXlogue(x)
+	return p
+}
+
+// LineNumber returns a string for the line number, "?" if it is not known.
+func (p XPos) LineNumber() string {
+	if !p.IsKnown() {
+		return "?"
+	}
+	return p.lico.lineNumber()
+}
+
+// FileIndex returns a smallish non-negative integer corresponding to the
+// file for this source position.  Smallish is relative; it can be thousands
+// large, but not millions.
+func (p XPos) FileIndex() int32 {
+	return p.index
+}
+
+func (p XPos) LineNumberHTML() string {
+	if !p.IsKnown() {
+		return "?"
+	}
+	return p.lico.lineNumberHTML()
+}
+
+// AtColumn1 returns the same location but shifted to column 1.
+func (p XPos) AtColumn1() XPos {
+	p.lico = p.lico.atColumn1()
+	return p
+}
+
+// A PosTable tracks Pos -> XPos conversions and vice versa.
+// Its zero value is a ready-to-use PosTable.
+type PosTable struct {
+	baseList []*PosBase
+	indexMap map[*PosBase]int
+	nameMap  map[string]int // Maps file symbol name to index for debug information.
+}
+
+// XPos returns the corresponding XPos for the given pos,
+// adding pos to t if necessary.
+func (t *PosTable) XPos(pos Pos) XPos {
+	m := t.indexMap
+	if m == nil {
+		// Create new list and map and populate with nil
+		// base so that NoPos always gets index 0.
+		t.baseList = append(t.baseList, nil)
+		m = map[*PosBase]int{nil: 0}
+		t.indexMap = m
+		t.nameMap = make(map[string]int)
+	}
+	i, ok := m[pos.base]
+	if !ok {
+		i = len(t.baseList)
+		t.baseList = append(t.baseList, pos.base)
+		t.indexMap[pos.base] = i
+		if _, ok := t.nameMap[pos.base.symFilename]; !ok {
+			t.nameMap[pos.base.symFilename] = len(t.nameMap)
+		}
+	}
+	return XPos{int32(i), pos.lico}
+}
+
+// Pos returns the corresponding Pos for the given p.
+// If p cannot be translated via t, the function panics.
+func (t *PosTable) Pos(p XPos) Pos {
+	var base *PosBase
+	if p.index != 0 {
+		base = t.baseList[p.index]
+	}
+	return Pos{base, p.lico}
+}
+
+// FileIndex returns the index of the given filename(symbol) in the PosTable, or -1 if not found.
+func (t *PosTable) FileIndex(filename string) int {
+	if v, ok := t.nameMap[filename]; ok {
+		return v
+	}
+	return -1
+}
+
+// FileTable returns a slice of all files used to build this package.
+func (t *PosTable) FileTable() []string {
+	// Create a LUT of the global package level file indices. This table is what
+	// is written in the debug_lines header, the file[N] will be referenced as
+	// N+1 in the debug_lines table.
+	fileLUT := make([]string, len(t.nameMap))
+	for str, i := range t.nameMap {
+		fileLUT[i] = str
+	}
+	return fileLUT
+}