github.com/slayercat/go@v0.0.0-20170428012452-c51559813f61/src/cmd/compile/internal/ssa/location.go (about)

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package ssa
     6  
     7  import "fmt"
     8  
     9  // A place that an ssa variable can reside.
    10  type Location interface {
    11  	Name() string // name to use in assembly templates: %rax, 16(%rsp), ...
    12  }
    13  
    14  // A Register is a machine register, like %rax.
    15  // They are numbered densely from 0 (for each architecture).
    16  type Register struct {
    17  	num    int32
    18  	objNum int16 // register number from cmd/internal/obj/$ARCH
    19  	name   string
    20  }
    21  
    22  func (r *Register) Name() string {
    23  	return r.name
    24  }
    25  
    26  // A LocalSlot is a location in the stack frame.
    27  // It is (possibly a subpiece of) a PPARAM, PPARAMOUT, or PAUTO ONAME node.
    28  type LocalSlot struct {
    29  	N    GCNode // an ONAME *gc.Node representing a variable on the stack
    30  	Type Type   // type of slot
    31  	Off  int64  // offset of slot in N
    32  }
    33  
    34  func (s LocalSlot) Name() string {
    35  	if s.Off == 0 {
    36  		return fmt.Sprintf("%v[%v]", s.N, s.Type)
    37  	}
    38  	return fmt.Sprintf("%v+%d[%v]", s.N, s.Off, s.Type)
    39  }
    40  
    41  type LocPair [2]Location
    42  
    43  func (t LocPair) Name() string {
    44  	n0, n1 := "nil", "nil"
    45  	if t[0] != nil {
    46  		n0 = t[0].Name()
    47  	}
    48  	if t[1] != nil {
    49  		n1 = t[1].Name()
    50  	}
    51  	return fmt.Sprintf("<%s,%s>", n0, n1)
    52  }