编译原理作业
编译原理作业
作业1:输出CL,GCC 词法分析,语法分析,语义分析的结果 即通过参数控制,分步完成编译过程。
答案:
一、 gcc 编译过程分为四段:预处理、编译、汇编、链接
预处理:
gcc-Ehello.c-ohello.i
● 参数-E 表示只进行预处理或者也可以使用以下指令完成预处理过程。 ● 将所有的#define删除,并且展开所有的宏定义
● 处理所有的条件预编译指令,比如#if,#ifdef,#elif,#else,#endif等。
● 处理#include预编译指令,将被包含的文件插入到该预编译指令的位置。 ● 删除所有注释“//”和”/**/”.
● 添加行号和文件标识,以便编译时产生调试用的行号及编译错误警告行号。
● 保留所有的#pragma编译器指令,因为编译器需要使用它们。 预处理结果:
# 1 "hello.c"
# 1 ""
# 1 ""
# 1 "hello.c"
# 1 "/usr/include/stdio.h" 1 3 4
# 28 "/usr/include/stdio.h" 3 4
# 1 "/usr/include/features.h" 1 3 4
# 363 "/usr/include/features.h" 3 4
# 1 "/usr/include/sys/cdefs.h" 1 3 4
# 372 "/usr/include/sys/cdefs.h" 3 4
# 1 "/usr/include/bits/wordsize.h" 1 3 4
# 373 "/usr/include/sys/cdefs.h" 2 3 4
# 364 "/usr/include/features.h" 2 3 4
# 387 "/usr/include/features.h" 3 4
# 1 "/usr/include/gnu/stubs.h" 1 3 4
# 1 "/usr/include/bits/wordsize.h" 1 3 4
# 5 "/usr/include/gnu/stubs.h" 2 3 4
# 1 "/usr/include/gnu/stubs-32.h" 1 3 4
# 8 "/usr/include/gnu/stubs.h" 2 3 4
# 388 "/usr/include/features.h" 2 3 4
# 29 "/usr/include/stdio.h" 2 3 4
# 1 "/usr/lib/gcc/i686-redhat-linux/4.6.2/include/stddef.h" 1 3 4 # 212 "/usr/lib/gcc/i686-redhat-linux/4.6.2/include/stddef.h" 3 4 typedef unsigned int size_t;
# 35 "/usr/include/stdio.h" 2 3 4
# 1 "/usr/include/bits/types.h" 1 3 4
# 28 "/usr/include/bits/types.h" 3 4
# 1 "/usr/include/bits/wordsize.h" 1 3 4
# 29 "/usr/include/bits/types.h" 2 3 4
typedef unsigned char __u_char;
typedef unsigned short int __u_short;
typedef unsigned int __u_int;
typedef unsigned long int __u_long;
typedef signed char __int8_t;
typedef unsigned char __uint8_t;
typedef signed short int __int16_t;
typedef unsigned short int __uint16_t;
typedef signed int __int32_t;
typedef unsigned int __uint32_t;
__extension__ typedef signed long long int __int64_t;
__extension__ typedef unsigned long long int __uint64_t;
__extension__ typedef long long int __quad_t;
__extension__ typedef unsigned long long int __u_quad_t;
# 131 "/usr/include/bits/types.h" 3 4
# 1 "/usr/include/bits/typesizes.h" 1 3 4
# 132 "/usr/include/bits/types.h" 2 3 4
__extension__ typedef __u_quad_t __dev_t;
__extension__ typedef unsigned int __uid_t;
__extension__ typedef unsigned int __gid_t;
__extension__ typedef unsigned long int __ino_t;
__extension__ typedef __u_quad_t __ino64_t;
__extension__ typedef unsigned int __mode_t;
__extension__ typedef unsigned int __nlink_t;
__extension__ typedef long int __off_t;
__extension__ typedef __quad_t __off64_t;
__extension__ typedef int __pid_t;
__extension__ typedef struct { int __val[2]; } __fsid_t;
__extension__ typedef long int __clock_t;
__extension__ typedef unsigned long int __rlim_t;
__extension__ typedef __u_quad_t __rlim64_t;
__extension__ typedef unsigned int __id_t;
__extension__ typedef long int __time_t;
__extension__ typedef unsigned int __useconds_t;
__extension__ typedef long int __suseconds_t;
__extension__ typedef int __daddr_t;
__extension__ typedef long int __swblk_t;
__extension__ typedef int __key_t;
__extension__ typedef int __clockid_t;
__extension__ typedef void * __timer_t;
__extension__ typedef long int __blksize_t;
__extension__ typedef long int __blkcnt_t;
__extension__ typedef __quad_t __blkcnt64_t;
__extension__ typedef unsigned long int __fsblkcnt_t;
__extension__ typedef __u_quad_t __fsblkcnt64_t;
__extension__ typedef unsigned long int __fsfilcnt_t;
__extension__ typedef __u_quad_t __fsfilcnt64_t;
__extension__ typedef int __ssize_t;
typedef __off64_t __loff_t;
typedef __quad_t *__qaddr_t;
typedef char *__caddr_t;
__extension__ typedef int __intptr_t;
__extension__ typedef unsigned int __socklen_t;
# 37 "/usr/include/stdio.h" 2 3 4
# 45 "/usr/include/stdio.h" 3 4
struct _IO_FILE;
typedef struct _IO_FILE FILE;
# 65 "/usr/include/stdio.h" 3 4
typedef struct _IO_FILE __FILE;
# 75 "/usr/include/stdio.h" 3 4
# 1 "/usr/include/libio.h" 1 3 4
# 32 "/usr/include/libio.h" 3 4
# 1 "/usr/include/_G_config.h" 1 3 4
# 15 "/usr/include/_G_config.h" 3 4
# 1 "/usr/lib/gcc/i686-redhat-linux/4.6.2/include/stddef.h" 1 3 4 # 16 "/usr/include/_G_config.h" 2 3 4
# 1 "/usr/include/wchar.h" 1 3 4
# 83 "/usr/include/wchar.h" 3 4
typedef struct
{
int __count;
union
{
unsigned int __wch;
char __wchb[4];
} __value;
} __mbstate_t;
# 21 "/usr/include/_G_config.h" 2 3 4
typedef struct
{
__off_t __pos;
__mbstate_t __state;
} _G_fpos_t;
typedef struct
{
__off64_t __pos;
__mbstate_t __state;
} _G_fpos64_t;
# 53 "/usr/include/_G_config.h" 3 4
typedef int _G_int16_t __attribute__ ((__mode__ (__HI__)));
typedef int _G_int32_t __attribute__ ((__mode__ (__SI__)));
typedef unsigned int _G_uint16_t __attribute__ ((__mode__ (__HI__)));
typedef unsigned int _G_uint32_t __attribute__ ((__mode__ (__SI__)));
# 33 "/usr/include/libio.h" 2 3 4
# 53 "/usr/include/libio.h" 3 4
# 1 "/usr/lib/gcc/i686-redhat-linux/4.6.2/include/stdarg.h" 1 3 4 # 40 "/usr/lib/gcc/i686-redhat-linux/4.6.2/include/stdarg.h" 3 4 typedef __builtin_va_list __gnuc_va_list;
# 54 "/usr/include/libio.h" 2 3 4
# 172 "/usr/include/libio.h" 3 4
struct _IO_jump_t; struct _IO_FILE;
# 182 "/usr/include/libio.h" 3 4
typedef void _IO_lock_t;
struct _IO_marker {
struct _IO_marker *_next;
struct _IO_FILE *_sbuf;
int _pos;
# 205 "/usr/include/libio.h" 3 4
};
enum __codecvt_result
{
__codecvt_ok,
__codecvt_partial,
__codecvt_error,
__codecvt_noconv
};
# 273 "/usr/include/libio.h" 3 4
struct _IO_FILE {
int _flags;
char* _IO_read_ptr;
char* _IO_read_end;
char* _IO_read_base;
char* _IO_write_base;
char* _IO_write_ptr;
char* _IO_write_end;
char* _IO_buf_base;
char* _IO_buf_end;
char *_IO_save_base;
char *_IO_backup_base;
char *_IO_save_end;
struct _IO_marker *_markers;
struct _IO_FILE *_chain;
int _fileno;
int _flags2;
__off_t _old_offset;
unsigned short _cur_column;
signed char _vtable_offset;
char _shortbuf[1];
_IO_lock_t *_lock;
# 321 "/usr/include/libio.h" 3 4
__off64_t _offset;
# 330 "/usr/include/libio.h" 3 4
void *__pad1;
void *__pad2;
void *__pad3;
void *__pad4;
size_t __pad5;
int _mode;
char _unused2[15 * sizeof (int) - 4 * sizeof (void *) - sizeof (size_t)];
};
typedef struct _IO_FILE _IO_FILE;
struct _IO_FILE_plus;
extern struct _IO_FILE_plus _IO_2_1_stdin_;
extern struct _IO_FILE_plus _IO_2_1_stdout_;
extern struct _IO_FILE_plus _IO_2_1_stderr_;
# 366 "/usr/include/libio.h" 3 4
typedef __ssize_t __io_read_fn (void *__cookie, char *__buf, size_t __nbytes);
typedef __ssize_t __io_write_fn (void *__cookie, __const char *__buf,
size_t __n);
typedef int __io_seek_fn (void *__cookie, __off64_t *__pos, int __w); typedef int __io_close_fn (void *__cookie);
# 418 "/usr/include/libio.h" 3 4
extern int __underflow (_IO_FILE *);
extern int __uflow (_IO_FILE *);
extern int __overflow (_IO_FILE *, int);
# 462 "/usr/include/libio.h" 3 4
extern int _IO_getc (_IO_FILE *__fp);
extern int _IO_putc (int __c, _IO_FILE *__fp);
extern int _IO_feof (_IO_FILE *__fp) __attribute__ ((__nothrow__)); extern int
((__nothrow__));
extern void _IO_ferror (_IO_FILE *__fp) __attribute__ extern int _IO_peekc_locked (_IO_FILE *__fp); _IO_flockfile (_IO_FILE *) __attribute__
((__nothrow__));
extern void
((__nothrow__));
extern int _IO_funlockfile _IO_ftrylockfile (_IO_FILE (_IO_FILE *) *) __attribute__ __attribute__ ((__nothrow__));
# 492 "/usr/include/libio.h" 3 4
extern int _IO_vfscanf (_IO_FILE * __restrict, const char * __restrict,
__gnuc_va_list, int *__restrict);
extern int _IO_vfprintf (_IO_FILE *__restrict, const char *__restrict,
__gnuc_va_list);
extern __ssize_t _IO_padn (_IO_FILE *, int, __ssize_t);
extern size_t _IO_sgetn (_IO_FILE *, void *, size_t);
extern __off64_t _IO_seekoff (_IO_FILE *, __off64_t, int, int); extern __off64_t _IO_seekpos (_IO_FILE *, __off64_t, int);
extern void _IO_free_backup_area (_IO_FILE *) __attribute__ ((__nothrow__));
# 76 "/usr/include/stdio.h" 2 3 4
typedef __gnuc_va_list va_list;
# 91 "/usr/include/stdio.h" 3 4
typedef __off_t off_t;
# 103 "/usr/include/stdio.h" 3 4
typedef __ssize_t ssize_t;
typedef _G_fpos_t fpos_t;
# 165 "/usr/include/stdio.h" 3 4
# 1 "/usr/include/bits/stdio_lim.h" 1 3 4
# 166 "/usr/include/stdio.h" 2 3 4
extern struct _IO_FILE *stdin;
extern struct _IO_FILE *stdout;
extern struct _IO_FILE *stderr;
extern int remove (__const char *__filename) __attribute__ ((__nothrow__));
extern int rename (__const char *__old, __const char *__new) __attribute__ ((__nothrow__));
extern int renameat (int __oldfd, __const char *__old, int __newfd,
__const char *__new) __attribute__ ((__nothrow__));
extern FILE *tmpfile (void) ;
# 212 "/usr/include/stdio.h" 3 4
extern char *tmpnam (char *__s) __attribute__ ((__nothrow__)) ; extern char *tmpnam_r (char *__s) __attribute__ ((__nothrow__)) ; # 230 "/usr/include/stdio.h" 3 4
extern char *tempnam (__const char *__dir, __const char *__pfx) __attribute__ ((__nothrow__)) __attribute__ ((__malloc__)) ; extern int fclose (FILE *__stream);
extern int fflush (FILE *__stream);
# 255 "/usr/include/stdio.h" 3 4
extern int fflush_unlocked (FILE *__stream);
# 269 "/usr/include/stdio.h" 3 4
extern FILE *fopen (__const char *__restrict __filename,
__const char *__restrict __modes) ;
extern FILE *freopen (__const char *__restrict __filename,
__const char *__restrict __modes,
FILE *__restrict __stream) ;
# 298 "/usr/include/stdio.h" 3 4
# 309 "/usr/include/stdio.h" 3 4
extern FILE *fdopen (int __fd, __const char *__modes) __attribute__ ((__nothrow__)) ;
# 322 "/usr/include/stdio.h" 3 4
extern FILE *fmemopen (void *__s, size_t __len, __const char *__modes)
__attribute__ ((__nothrow__)) ;
extern FILE *open_memstream (char **__bufloc, size_t *__sizeloc) __attribute__ ((__nothrow__)) ;
extern void setbuf (FILE *__restrict __stream, char *__restrict __buf) __attribute__ ((__nothrow__));
extern int setvbuf (FILE *__restrict __stream, char *__restrict __buf,
int __modes, size_t __n) __attribute__ ((__nothrow__));
extern void setbuffer (FILE *__restrict __stream, char *__restrict __buf,
size_t __size) __attribute__ ((__nothrow__));
extern void
((__nothrow__)); setlinebuf (FILE *__stream) __attribute__
extern int fprintf (FILE *__restrict __stream,
__const char *__restrict __format, ...);
extern int printf (__const char *__restrict __format, ...);
extern int sprintf (char *__restrict __s,
__const char *__restrict __format, ...) __attribute__ ((__nothrow__));
extern int vfprintf (FILE *__restrict __s, __const char *__restrict __format,
__gnuc_va_list __arg);
extern int vprintf (__const char *__restrict __format, __gnuc_va_list __arg);
extern int vsprintf (char *__restrict __s, __const char *__restrict __format,
__gnuc_va_list __arg) __attribute__ ((__nothrow__));
extern int snprintf (char *__restrict __s, size_t __maxlen,
__const char *__restrict __format, ...)
__attribute__ ((__nothrow__)) __attribute__ ((__format__ (__printf__, 3, 4)));
extern int vsnprintf (char *__restrict __s, size_t __maxlen,
__const char *__restrict __format, __gnuc_va_list __arg) __attribute__ ((__nothrow__)) __attribute__ ((__format__ (__printf__, 3, 0)));
# 420 "/usr/include/stdio.h" 3 4
extern int vdprintf (int __fd, __const char *__restrict __fmt, __gnuc_va_list __arg)
__attribute__ ((__format__ (__printf__, 2, 0)));
extern int dprintf (int __fd, __const char *__restrict __fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
extern int fscanf (FILE *__restrict __stream,
__const char *__restrict __format, ...) ;
extern int scanf (__const char *__restrict __format, ...) ;
extern int sscanf (__const char *__restrict __s,
__const char *__restrict __format, ...) __attribute__ ((__nothrow__));
# 451 "/usr/include/stdio.h" 3 4
extern int fscanf (FILE *__restrict __stream, __const char *__restrict __format, ...) __asm__ ("" "__isoc99_fscanf")
;
extern int scanf (__const char *__restrict __format, ...) __asm__ ("" "__isoc99_scanf")
;
extern int sscanf (__const char *__restrict __s, __const char *__restrict __format, ...) __asm__ ("" "__isoc99_sscanf") __attribute__ ((__nothrow__))
;
# 471 "/usr/include/stdio.h" 3 4
extern int vfscanf (FILE *__restrict __s, __const char *__restrict __format,
__gnuc_va_list __arg)
__attribute__ ((__format__ (__scanf__, 2, 0))) ;
extern int vscanf (__const char *__restrict __format, __gnuc_va_list __arg)
__attribute__ ((__format__ (__scanf__, 1, 0))) ;
extern int vsscanf (__const char *__restrict __s,
__const char *__restrict __format, __gnuc_va_list __arg) __attribute__ ((__nothrow__)) __attribute__ ((__format__ (__scanf__, 2, 0)));
# 502 "/usr/include/stdio.h" 3 4
extern int vfscanf (FILE *__restrict __s, __const char *__restrict __format, __gnuc_va_list __arg) __asm__ ("" "__isoc99_vfscanf")
__attribute__ ((__format__ (__scanf__, 2, 0))) ;
extern int vscanf (__const char *__restrict __format, __gnuc_va_list __arg) __asm__ ("" "__isoc99_vscanf")
__attribute__ ((__format__ (__scanf__, 1, 0))) ;
extern int vsscanf (__const char *__restrict __s, __const char *__restrict __format, __gnuc_va_list __arg) __asm__ ("" "__isoc99_vsscanf") __attribute__ ((__nothrow__))
__attribute__ ((__format__ (__scanf__, 2, 0)));
# 530 "/usr/include/stdio.h" 3 4
extern int fgetc (FILE *__stream);
extern int getc (FILE *__stream);
extern int getchar (void);
# 558 "/usr/include/stdio.h" 3 4
extern int getc_unlocked (FILE *__stream);
extern int getchar_unlocked (void);
# 569 "/usr/include/stdio.h" 3 4
extern int fgetc_unlocked (FILE *__stream);
extern int fputc (int __c, FILE *__stream);
extern int putc (int __c, FILE *__stream);
extern int putchar (int __c);
# 602 "/usr/include/stdio.h" 3 4
extern int fputc_unlocked (int __c, FILE *__stream);
extern int putc_unlocked (int __c, FILE *__stream);
extern int putchar_unlocked (int __c);
extern int getw (FILE *__stream);
extern int putw (int __w, FILE *__stream);
extern char *fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
;
extern char *gets (char *__s) ;
# 664 "/usr/include/stdio.h" 3 4
extern __ssize_t __getdelim (char **__restrict __lineptr, size_t *__restrict __n, int __delimiter,
FILE *__restrict __stream) ;
extern __ssize_t getdelim (char **__restrict __lineptr,
size_t *__restrict __n, int __delimiter,
FILE *__restrict __stream) ;
extern __ssize_t getline (char **__restrict __lineptr,
size_t *__restrict __n,
FILE *__restrict __stream) ;
extern int fputs (__const char *__restrict __s, FILE *__restrict __stream);
extern int puts (__const char *__s);
extern int ungetc (int __c, FILE *__stream);
extern size_t fread (void *__restrict __ptr, size_t __size, size_t __n, FILE *__restrict __stream) ;
extern size_t fwrite (__const void *__restrict __ptr, size_t __size, size_t __n, FILE *__restrict __s) ;
# 736 "/usr/include/stdio.h" 3 4
extern size_t fread_unlocked (void *__restrict __ptr, size_t __size, size_t __n, FILE *__restrict __stream) ;
extern size_t fwrite_unlocked (__const void *__restrict __ptr, size_t __size,
size_t __n, FILE *__restrict __stream) ;
extern int fseek (FILE *__stream, long int __off, int __whence); extern long int ftell (FILE *__stream) ;
extern void rewind (FILE *__stream);
# 772 "/usr/include/stdio.h" 3 4
extern int fseeko (FILE *__stream, __off_t __off, int __whence); extern __off_t ftello (FILE *__stream) ;
# 791 "/usr/include/stdio.h" 3 4
extern int fgetpos (FILE *__restrict __stream, fpos_t *__restrict __pos);
extern int fsetpos (FILE *__stream, __const fpos_t *__pos); # 814 "/usr/include/stdio.h" 3 4
# 823 "/usr/include/stdio.h" 3 4
extern void clearerr (FILE *__stream) __attribute__ ((__nothrow__)); extern int feof (FILE *__stream) __attribute__ ((__nothrow__)) ; extern int ferror (FILE *__stream) __attribute__ ((__nothrow__)) ; extern void clearerr_unlocked (FILE *__stream) __attribute__ ((__nothrow__));
extern int feof_unlocked
((__nothrow__)) ; (FILE *__stream) __attribute__
extern int ferror_unlocked (FILE *__stream) __attribute__ ((__nothrow__)) ;
extern void perror (__const char *__s);
# 1 "/usr/include/bits/sys_errlist.h" 1 3 4
# 27 "/usr/include/bits/sys_errlist.h" 3 4
extern int sys_nerr;
extern __const char *__const sys_errlist[];
# 853 "/usr/include/stdio.h" 2 3 4
extern int fileno (FILE *__stream) __attribute__ ((__nothrow__)) ; extern int fileno_unlocked (FILE *__stream) __attribute__ ((__nothrow__)) ;
# 872 "/usr/include/stdio.h" 3 4
extern FILE *popen (__const char *__command, __const char *__modes) ; extern int pclose (FILE *__stream);
extern char *ctermid (char *__s) __attribute__ ((__nothrow__)); # 912 "/usr/include/stdio.h" 3 4
extern void flockfile (FILE *__stream) __attribute__ ((__nothrow__));
extern int
((__nothrow__)) ;
extern void funlockfile (FILE *__stream) __attribute__ ftrylockfile (FILE *__stream) __attribute__
((__nothrow__));
# 942 "/usr/include/stdio.h" 3 4
# 2 "hello.c" 2
int main()
{
int n;
int i;
int sum=0;
scanf("%d",&n);
for(i=0;i
sum+=i;
printf("%d",&sum);
return sum;
}
编译:
编译过程就是把预处理完的文件进行一系列的词法分析,语法分析,语义分析及优化后生成相应的汇编代码。
gcc –Shello.i -ohello.s
编译过程可分为6步:扫描(词法分析)、语法分析、语义分析、源代码优化、代码生成、目标代码优化。
● 词法分析:扫描器(Scanner )将源代的字符序列分割成一系列的记号
(Token )。lex 工具可实现词法扫描。
● 语法分析:语法分析器将记号(Token )产生语法树(SyntaxTree )。yacc
工具可实现语法分析(yacc:YetAnotherCompilerCompiler)。
● 语义分析:静态语义(在编译器可以确定的语义)、动态语义(只能在
运行期才能确定的语义)。
● 源代码优化:源代码优化器(SourceCodeOptimizer),将整个语法书转
化为中间代码(IntermediateCode )(中间代码是与目标机器和运行环境无关的)。中间代码使得编译器被分为前端和后端。编译器前端负责产生机器无关的中间代码;编译器后端将中间代码转化为目标机器代码。 ● 目标代码生成:代码生成器(CodeGenerator).
● 目标代码优化:目标代码优化器(TargetCodeOptimizer)。
编译结果:
.file "hello.c"
.section .rodata
.LC0:
.string
.text "%d"
.globl main
.type main, @function
main:
.LFB0:
.cfi_startproc
pushl %ebp
.cfi_def_cfa_offset 8
.cfi_offset 5, -8
movl %esp, %ebp
.cfi_def_cfa_register 5
andl $-16, %esp
subl
movl
movl
leal
movl
movl
call $32, %esp $0, 20(%esp) $.LC0, %eax 24(%esp), %edx %edx, 4(%esp) %eax, (%esp) __isoc99_scanf
movl $0, 28(%esp)
jmp .L2
.L3:
movl
addl
movl
addl
.L2:
movl
cmpl
movl
leal
movl
movl
call 24(%esp), %eax %eax, 28(%esp) $.LC0, %eax 20(%esp), %edx %edx, 4(%esp) %eax, (%esp) printf 20(%esp), %eax 28(%esp), %eax %eax, 20(%esp) $1, 28(%esp) jl .L3
movl 20(%esp), %eax
leave
.cfi_restore 5
.cfi_def_cfa 4, 4
ret
.cfi_endproc
.LFE0:
.size main, .-main
.ident "GCC: (GNU) 4.6.2 20111027 (Red Hat 4.6.2-1)" .section .note.GNU-stack,"",@progbits
作业2:分别编写出无goto 的删空格与有goto 的删空格程序 答案:
无goto 的程序:
#include
using namespace std;
int main()
{
char b;
char a[50];
int i=0;
while(cin>>b)
{
if(b==48)
break;
if(b!=32)
{
a[i]=b;
i++;
}
}
for(int j=0;j
coutreturn 0;
}
有goto 的程序:
#include
using namespace std;
int main()
{
char b;
char a[50]; int i=0;
L1: cin>>b;
if(b==48) goto L2; if(b!=32) {
a[i]=b; i++; }
goto L1;
L2: for(int j=0;j}
void main()
{
readDat(); delete1(a,b); print(b);
}