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4ee0df8c46
Fixes #74076 Change-Id: Icc67b3d4e342f329584433bd1250c56ae8f5a73d Reviewed-on: https://go-review.googlesource.com/c/go/+/690635 Reviewed-by: Alan Donovan <adonovan@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Commit-Queue: Alan Donovan <adonovan@google.com> Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Keith Randall <khr@google.com> Auto-Submit: Alan Donovan <adonovan@google.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
73 lines
1.7 KiB
Go
73 lines
1.7 KiB
Go
// Copyright 2021 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package noder
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import (
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"cmd/compile/internal/base"
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"cmd/compile/internal/syntax"
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"cmd/internal/src"
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)
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// A posMap handles mapping from syntax.Pos to src.XPos.
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type posMap struct {
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bases map[*syntax.PosBase]*src.PosBase
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cache struct {
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last *syntax.PosBase
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base *src.PosBase
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}
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}
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type poser interface{ Pos() syntax.Pos }
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type ender interface{ End() syntax.Pos }
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func (m *posMap) pos(p poser) src.XPos { return m.makeXPos(p.Pos()) }
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func (m *posMap) makeXPos(pos syntax.Pos) src.XPos {
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// Predeclared objects (e.g., the result parameter for error.Error)
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// do not have a position.
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if !pos.IsKnown() {
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return src.NoXPos
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}
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posBase := m.makeSrcPosBase(pos.Base())
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return base.Ctxt.PosTable.XPos(src.MakePos(posBase, pos.Line(), pos.Col()))
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}
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// makeSrcPosBase translates from a *syntax.PosBase to a *src.PosBase.
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func (m *posMap) makeSrcPosBase(b0 *syntax.PosBase) *src.PosBase {
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// fast path: most likely PosBase hasn't changed
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if m.cache.last == b0 {
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return m.cache.base
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}
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b1, ok := m.bases[b0]
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if !ok {
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fn := b0.Filename()
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absfn := trimFilename(b0)
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if b0.IsFileBase() {
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b1 = src.NewFileBase(fn, absfn)
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} else {
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// line directive base
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p0 := b0.Pos()
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p0b := p0.Base()
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if p0b == b0 {
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panic("infinite recursion in makeSrcPosBase")
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}
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p1 := src.MakePos(m.makeSrcPosBase(p0b), p0.Line(), p0.Col())
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b1 = src.NewLinePragmaBase(p1, fn, absfn, b0.Line(), b0.Col())
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}
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if m.bases == nil {
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m.bases = make(map[*syntax.PosBase]*src.PosBase)
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}
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m.bases[b0] = b1
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}
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// update cache
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m.cache.last = b0
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m.cache.base = b1
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return b1
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}
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