/
to_asm.py
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/
to_asm.py
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"""
中间代码转汇编代码
作者：刘金明
博客：me.idealli.com
Github：github.com/flymysql
"""
from generate import creat_mcode
from other.function import if_num
global_head = """
;----------------------Welcome to Pcc--------------------------
; by 兰州小红鸡
;-------------------------------------------------------------------
"""
code_head = """
\t.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movq %rsp, %rbp
.cfi_def_cfa_register 6
"""
code_footer = """
\tmovl\t$0, %eax
leave
\t.cfi_def_cfa 7, 8
ret
\t.cfi_endproc
.LFE6:
.size\tmain, .-main
.ident\t"PCC: 1.0.0"
"""
"""
两个全局变量
LC 字符串计数
re 存储汇编代码
"""
LC = 0
re = ""
"""
agrs函数，解析变量，转为汇编语言可识别的变量
n：传入的变量，name变量名表
其中带[]的为数组变量，将会进行特殊的寻址处理
"""
def args(n, name):
global re
if n in name:
return "-" + name[n][0] + "(%rbp)"
elif "[]" in str(n):
ags = n.split("[]")
if if_num(ags[1]):
if name[ags[0]][1] == "char":
return "-" + str(int(name[ags[0]][0])-int(ags[1])) + "(%rbp)"
elif name[ags[0]][1] == "int":
return "-" + str(int(name[ags[0]][0])-int(ags[1])*4) + "(%rbp)"
else:
re += "\tmovl\t" + args(ags[1], name) + ", %eax\n\tcltq\n"
if name[ags[0]][1] == "char":
return "-" + name[ags[0]][0] + "(%rbp, %rax, 1)"
elif name[ags[0]][1] == "int":
return "-" + name[ags[0]][0] + "(%rbp, %rax, 4)"
elif "T" in str(n):
return n + "(%rip)"
elif if_num(str(n)):
return "$" + str(n)
else:
return n
"""
变量初始化，给每个变量初始化地址。
对于数组给予相应长度地址空间
返回值[re, len]
re为变量名地址对照表， len为需要数据栈的高度（这里我规定为12的倍数）
"""
def init_data(name_list, arrs):
re = {}
i = 0
for n in name_list:
if n['name'] != "main":
if n['flag'] == "int":
i += 4
re[n['name']] = [str(i), "int"]
elif n['flag'] == 'char':
i += 1
re[n['name']] = [str(i), "char"]
for a in arrs:
if arrs[a][1] == "int":
i += int(arrs[a][0])*4
re[a] = [str(i), "int"]
elif arrs[a][1] == "char":
i += int(arrs[a][0])
re[a] = [str(i), "char"]
return [re, (int(i/12) + 1)*12]
"""
字符串初始化
"""
def init_string(strings):
re = ""
for i in range(0, len(strings)):
re += ".LC" + str(i) + ":\n\t.string \"" + strings[i] + "\"\n"
return re
"""
汇编代码生成
传入参数：
1. midcode中间代码（四元式）
2. name变量地址参照表
可解析的汇编语句有
1. 赋值语句（op，=）
2. 四则运算（op，+-*/)
3. 跳转语句（op，j）
4. 输出语句（op，print）
"""
def generate_code(mid_code, name):
global re
re = ""
for m in mid_code:
# args = arg(m, name)
a1 = args(m.arg1, name)
a2 = args(m.arg2, name)
r = args(m.re, name)
if m.op == "=":
if m.re in name and name[m.re][1] == "char":
re += "\tmovb\t$" + str(ord(m.arg1)) + ", " + r + "\n"
elif m.arg1 in name or "T" in m.arg1 or "[]" in m.arg1:
re += "\tmovl\t" + a1 + ", %ecx\n"
re += "\tmovl\t%ecx, " + r + "\n"
else:
re += "\tmovl\t" + a1 + ", " + r + "\n"
elif m.op == "code_block":
re += "." + m.re + ":\n"
continue
elif "j" in m.op:
if m.op == "j":
re += "\tjmp\t." + m.re + "\n"
else:
re += "\tmovl\t" + a1 + ", %eax\n"
re += "\tcmpl\t" + a2 + ", %eax\n"
if ">" in m.op:
re += "\tjg\t." + m.re + "\n"
elif "<" in m.op:
re += "\tjle\t." + m.re + "\n"
elif "=" in m.op:
re += "\tje\t." + m.re + "\n"
elif m.op in "+-":
re += "\tmovl\t" + a1 +", %edx\n"
re += "\tmovl\t" + a2 +", %eax\n"
if m.op == "+":
re += "\taddl\t%edx, %eax\n"
else:
re += "\tsubl\t%edx, %eax\n"
re += "\tmovl\t%eax, " + r + "\n"
elif m.op in "*/":
if m.arg1 in name:
re += "\tmovl\t" + a2 +", %eax\n"
re += "\timull\t"+ a1 +", %eax\n"
re += "\tmovl\t%eax, "+ r +"\n"
elif m.arg2 in name and m.arg1 not in name:
re += "\tmovl\t" + a2 +", %eax\n"
re += "\timull\t"+ a1 +", %eax, %eax\n"
re += "\tmovl\t%eax, "+ r +"\n"
elif m.arg2 not in name and m.arg1 not in name:
num = int(m.arg2)*int(m.arg1)
re += "\tmovl\t$" + str(num) +", "+ r +"\n"
elif m.op == "print":
global LC
if m.arg1 != "-1":
if m.arg1 in name and name[m.arg1][1] == "char":
re += "\tmovsbl\t" + a1 + ", %eax\n"
else:
re += "\tmovl\t" + a1 + ", %eax\n"
if m.arg2 != "-1":
if m.arg2 in name and name[m.arg2][1] == "char":
re += "\tmovsbl\t" + a2 + ", %edx\n"
else:
re += "\tmovl\t" + a2 + ", %edx\n"
if m.re != "-1":
if m.re in name and name[m.re][1] == "char":
re += "\tmovsbl\t" + r + ", %ecx\n"
else:
re += "\tmovl\t" + r + ", %ecx\n"
re += "\tmovl\t%eax, %esi\n" + "\tleaq\t.LC" + str(LC) + "(%rip), %rdi\n"
LC += 1
re += "\tmovl\t$0, %eax\n\tcall\tprintf@PLT\n"
return re
"""
字符串拼接函数
将生成的临时变量，汇编代码，头部，结束部分等一些内容拼接在一起
传入参数：
1. tmp 临时变量（其实在代码里作为全局变量）
2. strs 字符串变量
3. code 主函数汇编代码
4. subq 数据栈高度
"""
def connect(tmp, strs, code, subq):
data = ""
for i in range(0, tmp):
data += "\t.comm\tT" + str(i) + ",4,4\n"
re = "\t.text\n\t.section\t.rodata\n" + data + strs + \
"\t.text\n\t.globl main\n\t.type main, @function\nmain:\n" + code_head +\
"\tsubq\t$" + str(subq) + ", %rsp\n" + code + code_footer
return re
"""
入口函数
生成汇编代码.s文件
后续的链接等工作将交给gcc
"""
def to_asm(filename):
global LC
LC = 0
mid_result = creat_mcode(filename)
mid_code = mid_result['mid_code']
name_list = mid_result['name_list']
tmp = mid_result['tmp']
strings = mid_result['strings']
arrs = mid_result['arrs']
name = init_data(name_list, arrs)
string_list = init_string(strings)
asm = generate_code(mid_code, name[0])
result = connect(tmp, string_list, asm, name[1])
re_asm = open(filename[:-1] + "s", "w").write(result)
if __name__ == "__main__":
to_asm("./test/test.c")