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
5package ssa
6
7// convert to machine-dependent ops.
8func lower(f *Func) {
9	// repeat rewrites until we find no more rewrites
10	applyRewrite(f, f.Config.lowerBlock, f.Config.lowerValue, removeDeadValues)
11}
12
13// lateLower applies those rules that need to be run after the general lower rules.
14func lateLower(f *Func) {
15	// repeat rewrites until we find no more rewrites
16	if f.Config.lateLowerValue != nil {
17		applyRewrite(f, f.Config.lateLowerBlock, f.Config.lateLowerValue, removeDeadValues)
18	}
19}
20
21// checkLower checks for unlowered opcodes and fails if we find one.
22func checkLower(f *Func) {
23	// Needs to be a separate phase because it must run after both
24	// lowering and a subsequent dead code elimination (because lowering
25	// rules may leave dead generic ops behind).
26	for _, b := range f.Blocks {
27		for _, v := range b.Values {
28			if !opcodeTable[v.Op].generic {
29				continue // lowered
30			}
31			switch v.Op {
32			case OpSP, OpSPanchored, OpSB, OpInitMem, OpArg, OpArgIntReg, OpArgFloatReg, OpPhi, OpVarDef, OpVarLive, OpKeepAlive, OpSelect0, OpSelect1, OpSelectN, OpConvert, OpInlMark, OpWBend:
33				continue // ok not to lower
34			case OpMakeResult:
35				if b.Controls[0] == v {
36					continue
37				}
38			case OpGetG:
39				if f.Config.hasGReg {
40					// has hardware g register, regalloc takes care of it
41					continue // ok not to lower
42				}
43			}
44			s := "not lowered: " + v.String() + ", " + v.Op.String() + " " + v.Type.SimpleString()
45
46			for _, a := range v.Args {
47				s += " " + a.Type.SimpleString()
48			}
49			f.Fatalf("%s", s)
50		}
51	}
52}
53