// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package astutil

// This file defines utilities for working with source positions.

import (
	"fmt"
	"go/ast"
	"go/token"
	"sort"
)

// PathEnclosingInterval returns the node that encloses the source
// interval [start, end), and all its ancestors up to the AST root.
//

// Eliminates unusued results from an operation `op` by cloning it with reduced
// result types and doing appropriate use replacements. `results_to_eliminate`
// is a bitvector of result positions to eliminate. If its null, then all unused
// results of the operation will be eliminated.
void EliminateUnusedResults(
    Operation *op, const llvm::BitVector *results_to_eliminate = nullptr) {

  //   - 'set': `X + Y` performs a union where the array positions of all elements in `X` are preserved and
  //     non-intersecting elements in `Y` are appended, retaining their partial order.
  //   - 'map': `X + Y` performs a merge where the array positions of all keys in `X` are preserved but the values

	//   - 'set': `X + Y` performs a union where the array positions of all elements in `X` are preserved and
	//     non-intersecting elements in `Y` are appended, retaining their partial order.
	//   - 'map': `X + Y` performs a merge where the array positions of all keys in `X` are preserved but the values

   * printing space backward on the same printing line. (Applicable also to display devices.)
   *
   * @since 8.0
   */
  public static final byte BS = 8;

  /**
   * Horizontal Tabulation ('\t'): A format effector which controls the movement of the printing
   * position to the next in a series of predetermined positions along the printing line.

		i2 := <-i2range

		if i2.Name != i1.Name {
			t.Errorf("got ident %s; want %s", i2.Name, i1.Name)
		}

		// here we care about the relative (line-directive adjusted) positions
		l1 := fset.Position(i1.Pos()).Line
		l2 := fset.Position(i2.Pos()).Line
		if l2 != l1 {
			t.Errorf("got line %d; want %d for %s", l2, l1, i1.Name)
		}
	}

	if t.Failed() {
		t.Logf("\n%s", buf.Bytes())
	}
}

	return &reader{
		Decoder: pr.TempDecoder(k, idx, marker),
		p:       pr,
	}
}

func (pr *pkgReader) retireReader(r *reader) {
	pr.RetireDecoder(&r.Decoder)
}

// @@@ Positions

func (r *reader) pos() token.Pos {
	r.Sync(pkgbits.SyncPos)
	if !r.Bool() {
		return token.NoPos
	}

	// TODO(mdempsky): Delta encoding.
	posBase := r.posBase()
	line := r.Uint()

// The supplied position is used as the position of the new value.
// Because this is used for rematerialization, check for case that (rematerialized)
// input to value with position 'pos' carried a statement mark, and that the supplied
// position (of the instruction using the rematerialized value) is not marked, and
// preserve that mark if its line matches the supplied position.

	// Base, Script, and Region methods. Once the transition is fully completed
	// the ID can be stripped from the name.

	LangID   Language
	RegionID Region
	// TODO: we will soon run out of positions for ScriptID. Idea: instead of
	// storing lang, region, and ScriptID codes, store only the compact index and
	// have a lookup table from this code to its expansion. This greatly speeds

}

// InnermostFilename returns a string containing the innermost
// (in inlining) filename at p's position
func (p *Prog) InnermostFilename() string {
	// TODO For now, this is only used for debugging output, and if we need more/better information, it might change.
	// An example of what we might want to see is the full stack of positions for inlined code, so we get some visibility into what is recorded there.
	pos := p.Ctxt.InnermostPos(p.Pos)