1#!/bin/bash
2# Downloads the Go sources, building the assembler into a standalone package.
3
4OUT_DIR=$(pwd)
5BASE_PKG_PATH='github.com/twitchyliquid64/golang-asm'
6
7TMP_PATH=$(mktemp -d)
8cleanup () {
9 if [[ "${TMP_PATH}" != "" ]]; then
10 rm -rf "${TMP_PATH}"
11 TMP_PATH=""
12 fi
13}
14trap 'cleanup $LINENO' ERR EXIT
15
16cd $TMP_PATH
17git clone --depth 1 https://github.com/golang/go
18
19rm -rfv ${OUT_DIR}/{asm,dwarf,obj,objabi,src,sys,bio,goobj}
20
21# Move obj.
22cp -rv ${TMP_PATH}/go/src/cmd/internal/obj ${OUT_DIR}/obj
23find ${OUT_DIR}/obj -type f -exec sed -i "s_\"cmd/internal/obj_\"${BASE_PKG_PATH}/obj_g" {} \;
24find ${OUT_DIR}/obj -type f -exec sed -i "s_\"cmd/internal/dwarf_\"${BASE_PKG_PATH}/dwarf_g" {} \;
25find ${OUT_DIR}/obj -type f -exec sed -i "s_\"cmd/internal/src_\"${BASE_PKG_PATH}/src_g" {} \;
26find ${OUT_DIR}/obj -type f -exec sed -i "s_\"cmd/internal/sys_\"${BASE_PKG_PATH}/sys_g" {} \;
27find ${OUT_DIR}/obj -type f -exec sed -i "s_\"cmd/internal/bio_\"${BASE_PKG_PATH}/bio_g" {} \;
28find ${OUT_DIR}/obj -type f -exec sed -i "s_\"cmd/internal/goobj_\"${BASE_PKG_PATH}/goobj_g" {} \;
29# Move objabi.
30cp -rv ${TMP_PATH}/go/src/cmd/internal/objabi ${OUT_DIR}/objabi
31find ${OUT_DIR}/objabi -type f -exec sed -i "s_\"cmd/internal/obj_\"${BASE_PKG_PATH}/obj_g" {} \;
32find ${OUT_DIR}/objabi -type f -exec sed -i "s_\"cmd/internal/dwarf_\"${BASE_PKG_PATH}/dwarf_g" {} \;
33find ${OUT_DIR}/objabi -type f -exec sed -i "s_\"cmd/internal/src_\"${BASE_PKG_PATH}/src_g" {} \;
34find ${OUT_DIR}/objabi -type f -exec sed -i "s_\"cmd/internal/sys_\"${BASE_PKG_PATH}/sys_g" {} \;
35find ${OUT_DIR}/objabi -type f -exec sed -i "s_\"cmd/internal/bio_\"${BASE_PKG_PATH}/bio_g" {} \;
36find ${OUT_DIR}/objabi -type f -exec sed -i "s_\"cmd/internal/goobj_\"${BASE_PKG_PATH}/goobj_g" {} \;
37# Move arch.
38mkdir -pv ${OUT_DIR}/asm
39cp -rv ${TMP_PATH}/go/src/cmd/asm/internal/arch ${OUT_DIR}/asm/arch
40find ${OUT_DIR}/asm/arch -type f -exec sed -i "s_\"cmd/internal/obj_\"${BASE_PKG_PATH}/obj_g" {} \;
41find ${OUT_DIR}/asm/arch -type f -exec sed -i "s_\"cmd/internal/dwarf_\"${BASE_PKG_PATH}/dwarf_g" {} \;
42find ${OUT_DIR}/asm/arch -type f -exec sed -i "s_\"cmd/internal/src_\"${BASE_PKG_PATH}/src_g" {} \;
43find ${OUT_DIR}/asm/arch -type f -exec sed -i "s_\"cmd/internal/sys_\"${BASE_PKG_PATH}/sys_g" {} \;
44find ${OUT_DIR}/asm/arch -type f -exec sed -i "s_\"cmd/internal/bio_\"${BASE_PKG_PATH}/bio_g" {} \;
45find ${OUT_DIR}/asm/arch -type f -exec sed -i "s_\"cmd/internal/goobj_\"${BASE_PKG_PATH}/goobj_g" {} \;
46# Move goobj.
47cp -rv ${TMP_PATH}/go/src/cmd/internal/goobj ${OUT_DIR}/goobj
48find ${OUT_DIR}/goobj -type f -exec sed -i "s_\"cmd/internal/obj_\"${BASE_PKG_PATH}/obj_g" {} \;
49find ${OUT_DIR}/goobj -type f -exec sed -i "s_\"cmd/internal/bio_\"${BASE_PKG_PATH}/bio_g" {} \;
50find ${OUT_DIR}/goobj -type f -exec sed -i "s_\"internal/unsafeheader_\"${BASE_PKG_PATH}/unsafeheader_g" {} \;
51
52# Move bio.
53cp -rv ${TMP_PATH}/go/src/cmd/internal/bio ${OUT_DIR}/bio
54# Move unsafeheader.
55cp -rv ${TMP_PATH}/go/src/internal/unsafeheader ${OUT_DIR}/unsafeheader
56# Move dwarf.
57cp -rv ${TMP_PATH}/go/src/cmd/internal/dwarf ${OUT_DIR}/dwarf
58find ${OUT_DIR}/dwarf -type f -exec sed -i "s_\"cmd/internal/obj_\"${BASE_PKG_PATH}/obj_g" {} \;
59# Move src.
60cp -rv ${TMP_PATH}/go/src/cmd/internal/src ${OUT_DIR}/src
61# Move sys.
62cp -rv ${TMP_PATH}/go/src/cmd/internal/sys ${OUT_DIR}/sys
63
64
65# Rewrite identifiers for generated (at build time) constants.
66find ${OUT_DIR}/objabi -type f -exec sed -i "s/stackGuardMultiplierDefault/1/g" {} \;
67find ${OUT_DIR}/objabi -type f -exec sed -i "s/defaultGOOS/\"linux\"/g" {} \;
68find ${OUT_DIR}/objabi -type f -exec sed -i "s/defaultGOARCH/\"$(go env GOARCH)\"/g" {} \;
69
70find ${OUT_DIR}/objabi -type f -exec sed -i "s/defaultGO386/\"\"/g" {} \;
71find ${OUT_DIR}/objabi -type f -exec sed -i "s/defaultGOARM/\"7\"/g" {} \;
72find ${OUT_DIR}/objabi -type f -exec sed -i "s/defaultGOMIPS64/\"hardfloat\"/g" {} \;
73find ${OUT_DIR}/objabi -type f -exec sed -i "s/defaultGOMIPS/\"hardfloat\"/g" {} \;
74find ${OUT_DIR}/objabi -type f -exec sed -i "s/defaultGOPPC64/\"power8\"/g" {} \;
75find ${OUT_DIR}/objabi -type f -exec sed -i "s/defaultGO_LDSO/\"\"/g" {} \;
76find ${OUT_DIR}/objabi -type f -exec sed -i "s/= version/= \"\"/g" {} \;
77find ${OUT_DIR}/objabi -type f -exec sed -i "s/defaultGO_EXTLINK_ENABLED/\"\"/g" {} \;
78find ${OUT_DIR}/objabi -type f -exec sed -i "s/goexperiment/\"\"/g" {} \;
79
80
81# Remove tests (they have package dependencies we could do without).
82find ${OUT_DIR} -name "*_test.go" -type f -delete
83
84# Write README.
85cat > ${OUT_DIR}/README.md << "EOF"
86# golang-asm
87
88A mirror of the assembler from the Go compiler, with import paths re-written for the assembler to be functional as a standalone library.
89
90License as per the Go project.
91
92# Status
93
94Works, but expect to dig into the assembler godoc's to work out what to set different parameters of `obj.Prog` to get it to generate specific instructions.
95
96# Example
97
98Demonstrates assembly of a NOP & an ADD instruction on x86-64.
99
100```go
101
102package main
103
104import (
105 "fmt"
106
107 asm "github.com/twitchyliquid64/golang-asm"
108 "github.com/twitchyliquid64/golang-asm/obj"
109 "github.com/twitchyliquid64/golang-asm/obj/x86"
110)
111
112func noop(builder *asm.Builder) *obj.Prog {
113 prog := builder.NewProg()
114 prog.As = x86.ANOPL
115 prog.From.Type = obj.TYPE_REG
116 prog.From.Reg = x86.REG_AX
117 return prog
118}
119
120func addImmediateByte(builder *asm.Builder, in int32) *obj.Prog {
121 prog := builder.NewProg()
122 prog.As = x86.AADDB
123 prog.To.Type = obj.TYPE_REG
124 prog.To.Reg = x86.REG_AL
125 prog.From.Type = obj.TYPE_CONST
126 prog.From.Offset = int64(in)
127 return prog
128}
129
130func movImmediateByte(builder *asm.Builder, reg int16, in int32) *obj.Prog {
131 prog := builder.NewProg()
132 prog.As = x86.AMOVB
133 prog.To.Type = obj.TYPE_REG
134 prog.To.Reg = reg
135 prog.From.Type = obj.TYPE_CONST
136 prog.From.Offset = int64(in)
137 return prog
138}
139
140func main() {
141 b, _ := asm.NewBuilder("amd64", 64)
142 b.AddInstruction(noop(b))
143 b.AddInstruction(movImmediateByte(b, x86.REG_AL, 16))
144 b.AddInstruction(addImmediateByte(b, 16))
145 fmt.Printf("Bin: %x\n", b.Assemble())
146}
147
148```
149
150# Working out the parameters of `obj.Prog`
151
152This took me some time to work out, so I'll write a bit here.
153
154## Use these references
155
156 * `obj.Prog` - [godoc](https://godoc.org/github.com/golang/go/src/cmd/internal/obj#Prog)
157 * Some instructions (like NOP, JMP) are abstract per-platform & can be found [here](https://godoc.org/github.com/golang/go/src/cmd/internal/obj#As)
158
159 * (for amd64) `x86 pkg-constants` - [registers & instructions](https://godoc.org/github.com/golang/go/src/cmd/internal/obj/x86#pkg-constant)
160
161## Instruction constants have a naming scheme
162
163Instructions are defined as constants in the package for the relavant architecture, and have an 'A' prefix and a size suffix.
164
165For example, the MOV instruction for 64 bits of data is `AMOVQ` (well, at least in amd64).
166
167## Search the go source for usage of a given instruction
168
169For example, if I wanted to work out how to emit the MOV instruction for 64bits, I would search the go source on github for `AMOVQ` or `x86.AMOVQ`. Normally, you see find a few examples where the compiler backend fills in a `obj.Prog` structure, and you follow it's lead.
170EOF
171
172# Write license file.
173cat > ${OUT_DIR}/LICENSE << "EOF"
174Copyright (c) 2009 The Go Authors. All rights reserved.
175
176Redistribution and use in source and binary forms, with or without
177modification, are permitted provided that the following conditions are
178met:
179
180 * Redistributions of source code must retain the above copyright
181notice, this list of conditions and the following disclaimer.
182 * Redistributions in binary form must reproduce the above
183copyright notice, this list of conditions and the following disclaimer
184in the documentation and/or other materials provided with the
185distribution.
186 * Neither the name of Google Inc. nor the names of its
187contributors may be used to endorse or promote products derived from
188this software without specific prior written permission.
189
190THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
191"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
192LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
193A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
194OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
195SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOTto be standalone
196LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
197DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
198THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
199(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
200OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
201EOF
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