diff options
Diffstat (limited to 'vendor/github.com/twitchyliquid64/golang-asm/src/pos.go')
| -rw-r--r-- | vendor/github.com/twitchyliquid64/golang-asm/src/pos.go | 470 |
1 files changed, 0 insertions, 470 deletions
diff --git a/vendor/github.com/twitchyliquid64/golang-asm/src/pos.go b/vendor/github.com/twitchyliquid64/golang-asm/src/pos.go deleted file mode 100644 index b6816a56e..000000000 --- a/vendor/github.com/twitchyliquid64/golang-asm/src/pos.go +++ /dev/null @@ -1,470 +0,0 @@ -// 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 := © - 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() -} |