1 files changed, 0 insertions, 234 deletions
diff --git a/vendor/golang.org/x/tools/go/ssa/ssautil/switch.go b/vendor/golang.org/x/tools/go/ssa/ssautil/switch.go
deleted file mode 100644
index db03bf5..0000000
--- a/vendor/golang.org/x/tools/go/ssa/ssautil/switch.go
+++ /dev/null
@@ -1,234 +0,0 @@
-// 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.
-
-package ssautil
-
-// This file implements discovery of switch and type-switch constructs
-// from low-level control flow.
-//
-// Many techniques exist for compiling a high-level switch with
-// constant cases to efficient machine code.  The optimal choice will
-// depend on the data type, the specific case values, the code in the
-// body of each case, and the hardware.
-// Some examples:
-// - a lookup table (for a switch that maps constants to constants)
-// - a computed goto
-// - a binary tree
-// - a perfect hash
-// - a two-level switch (to partition constant strings by their first byte).
-
-import (
-	"bytes"
-	"fmt"
-	"go/token"
-	"go/types"
-
-	"golang.org/x/tools/go/ssa"
-)
-
-// A ConstCase represents a single constant comparison.
-// It is part of a Switch.
-type ConstCase struct {
-	Block *ssa.BasicBlock // block performing the comparison
-	Body  *ssa.BasicBlock // body of the case
-	Value *ssa.Const      // case comparand
-}
-
-// A TypeCase represents a single type assertion.
-// It is part of a Switch.
-type TypeCase struct {
-	Block   *ssa.BasicBlock // block performing the type assert
-	Body    *ssa.BasicBlock // body of the case
-	Type    types.Type      // case type
-	Binding ssa.Value       // value bound by this case
-}
-
-// A Switch is a logical high-level control flow operation
-// (a multiway branch) discovered by analysis of a CFG containing
-// only if/else chains.  It is not part of the ssa.Instruction set.
-//
-// One of ConstCases and TypeCases has length >= 2;
-// the other is nil.
-//
-// In a value switch, the list of cases may contain duplicate constants.
-// A type switch may contain duplicate types, or types assignable
-// to an interface type also in the list.
-// TODO(adonovan): eliminate such duplicates.
-//
-type Switch struct {
-	Start      *ssa.BasicBlock // block containing start of if/else chain
-	X          ssa.Value       // the switch operand
-	ConstCases []ConstCase     // ordered list of constant comparisons
-	TypeCases  []TypeCase      // ordered list of type assertions
-	Default    *ssa.BasicBlock // successor if all comparisons fail
-}
-
-func (sw *Switch) String() string {
-	// We represent each block by the String() of its
-	// first Instruction, e.g. "print(42:int)".
-	var buf bytes.Buffer
-	if sw.ConstCases != nil {
-		fmt.Fprintf(&buf, "switch %s {\n", sw.X.Name())
-		for _, c := range sw.ConstCases {
-			fmt.Fprintf(&buf, "case %s: %s\n", c.Value, c.Body.Instrs[0])
-		}
-	} else {
-		fmt.Fprintf(&buf, "switch %s.(type) {\n", sw.X.Name())
-		for _, c := range sw.TypeCases {
-			fmt.Fprintf(&buf, "case %s %s: %s\n",
-				c.Binding.Name(), c.Type, c.Body.Instrs[0])
-		}
-	}
-	if sw.Default != nil {
-		fmt.Fprintf(&buf, "default: %s\n", sw.Default.Instrs[0])
-	}
-	fmt.Fprintf(&buf, "}")
-	return buf.String()
-}
-
-// Switches examines the control-flow graph of fn and returns the
-// set of inferred value and type switches.  A value switch tests an
-// ssa.Value for equality against two or more compile-time constant
-// values.  Switches involving link-time constants (addresses) are
-// ignored.  A type switch type-asserts an ssa.Value against two or
-// more types.
-//
-// The switches are returned in dominance order.
-//
-// The resulting switches do not necessarily correspond to uses of the
-// 'switch' keyword in the source: for example, a single source-level
-// switch statement with non-constant cases may result in zero, one or
-// many Switches, one per plural sequence of constant cases.
-// Switches may even be inferred from if/else- or goto-based control flow.
-// (In general, the control flow constructs of the source program
-// cannot be faithfully reproduced from the SSA representation.)
-//
-func Switches(fn *ssa.Function) []Switch {
-	// Traverse the CFG in dominance order, so we don't
-	// enter an if/else-chain in the middle.
-	var switches []Switch
-	seen := make(map[*ssa.BasicBlock]bool) // TODO(adonovan): opt: use ssa.blockSet
-	for _, b := range fn.DomPreorder() {
-		if x, k := isComparisonBlock(b); x != nil {
-			// Block b starts a switch.
-			sw := Switch{Start: b, X: x}
-			valueSwitch(&sw, k, seen)
-			if len(sw.ConstCases) > 1 {
-				switches = append(switches, sw)
-			}
-		}
-
-		if y, x, T := isTypeAssertBlock(b); y != nil {
-			// Block b starts a type switch.
-			sw := Switch{Start: b, X: x}
-			typeSwitch(&sw, y, T, seen)
-			if len(sw.TypeCases) > 1 {
-				switches = append(switches, sw)
-			}
-		}
-	}
-	return switches
-}
-
-func valueSwitch(sw *Switch, k *ssa.Const, seen map[*ssa.BasicBlock]bool) {
-	b := sw.Start
-	x := sw.X
-	for x == sw.X {
-		if seen[b] {
-			break
-		}
-		seen[b] = true
-
-		sw.ConstCases = append(sw.ConstCases, ConstCase{
-			Block: b,
-			Body:  b.Succs[0],
-			Value: k,
-		})
-		b = b.Succs[1]
-		if len(b.Instrs) > 2 {
-			// Block b contains not just 'if x == k',
-			// so it may have side effects that
-			// make it unsafe to elide.
-			break
-		}
-		if len(b.Preds) != 1 {
-			// Block b has multiple predecessors,
-			// so it cannot be treated as a case.
-			break
-		}
-		x, k = isComparisonBlock(b)
-	}
-	sw.Default = b
-}
-
-func typeSwitch(sw *Switch, y ssa.Value, T types.Type, seen map[*ssa.BasicBlock]bool) {
-	b := sw.Start
-	x := sw.X
-	for x == sw.X {
-		if seen[b] {
-			break
-		}
-		seen[b] = true
-
-		sw.TypeCases = append(sw.TypeCases, TypeCase{
-			Block:   b,
-			Body:    b.Succs[0],
-			Type:    T,
-			Binding: y,
-		})
-		b = b.Succs[1]
-		if len(b.Instrs) > 4 {
-			// Block b contains not just
-			//  {TypeAssert; Extract #0; Extract #1; If}
-			// so it may have side effects that
-			// make it unsafe to elide.
-			break
-		}
-		if len(b.Preds) != 1 {
-			// Block b has multiple predecessors,
-			// so it cannot be treated as a case.
-			break
-		}
-		y, x, T = isTypeAssertBlock(b)
-	}
-	sw.Default = b
-}
-
-// isComparisonBlock returns the operands (v, k) if a block ends with
-// a comparison v==k, where k is a compile-time constant.
-//
-func isComparisonBlock(b *ssa.BasicBlock) (v ssa.Value, k *ssa.Const) {
-	if n := len(b.Instrs); n >= 2 {
-		if i, ok := b.Instrs[n-1].(*ssa.If); ok {
-			if binop, ok := i.Cond.(*ssa.BinOp); ok && binop.Block() == b && binop.Op == token.EQL {
-				if k, ok := binop.Y.(*ssa.Const); ok {
-					return binop.X, k
-				}
-				if k, ok := binop.X.(*ssa.Const); ok {
-					return binop.Y, k
-				}
-			}
-		}
-	}
-	return
-}
-
-// isTypeAssertBlock returns the operands (y, x, T) if a block ends with
-// a type assertion "if y, ok := x.(T); ok {".
-//
-func isTypeAssertBlock(b *ssa.BasicBlock) (y, x ssa.Value, T types.Type) {
-	if n := len(b.Instrs); n >= 4 {
-		if i, ok := b.Instrs[n-1].(*ssa.If); ok {
-			if ext1, ok := i.Cond.(*ssa.Extract); ok && ext1.Block() == b && ext1.Index == 1 {
-				if ta, ok := ext1.Tuple.(*ssa.TypeAssert); ok && ta.Block() == b {
-					// hack: relies upon instruction ordering.
-					if ext0, ok := b.Instrs[n-3].(*ssa.Extract); ok {
-						return ext0, ta.X, ta.AssertedType
-					}
-				}
-			}
-		}
-	}
-	return
-}