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z0.c
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z0.c
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/*
Z0 -- Bootstrap assembler
*/
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <limits.h>
#include <unistd.h>
#include <stddef.h>
#include <string.h>
#include <stdbool.h>
#include <ctype.h>
#include <fcntl.h>
#include <elf.h>
#include <obstack.h>
bool verbose = false;
const char *in_name;
int lineno;
__attribute__ ((noreturn))
void
exitf (int code, char *fmt, ...)
{
va_list ap;
va_start (ap, fmt);
vfprintf (stderr, fmt, ap);
va_end (ap);
fprintf (stderr, "\n");
exit (code);
}
size_t total_alloc = 0;
void *
xmalloc (size_t size)
{
total_alloc += size;
if (total_alloc > 1<<30)
exitf (1, "out of memory");
void *mem = malloc (size);
if (mem == 0)
exitf (1, "Out of memory");
return mem;
}
#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free
/* Code */
uint8_t *code;
uint64_t code_offset;
uint64_t code_max;
struct obstack symtab_obs;
struct obstack strtab_obs;
struct file {
Elf64_Ehdr h;
Elf64_Phdr ph[2];
Elf64_Shdr sh[4];
};
uint64_t code_vaddr;
uint64_t code_start;
void
set_code_start (uint64_t start)
{
code_vaddr = start;
code_start = code_vaddr + sizeof(struct file);
}
uint64_t
strtab_add (const char *str)
{
uint64_t offset = obstack_object_size (&strtab_obs);
obstack_grow0 (&strtab_obs, str, strlen (str));
return offset;
}
void
symtab_add_raw (Elf64_Sym *sym)
{
obstack_grow (&symtab_obs, sym, sizeof (Elf64_Sym));
}
void
symtab_add (const char *name, uint64_t value)
{
Elf64_Sym sym;
sym.st_name = strtab_add (name);
sym.st_info = ELF64_ST_INFO (STB_GLOBAL, STT_NOTYPE);
sym.st_other = STV_DEFAULT;
sym.st_shndx = 1;
sym.st_value = value;
sym.st_size = 0;
symtab_add_raw (&sym);
}
void
init_code()
{
if (code_start == 0)
set_code_start (0x40000000);
code_max = 1024*1024 - (code_start - code_vaddr);
code = xmalloc (code_max);
code_offset = 0;
obstack_init (&symtab_obs);
obstack_init (&strtab_obs);
strtab_add ("");
Elf64_Sym sym;
sym.st_name = 0;
sym.st_info = 0;
sym.st_other = 0;
sym.st_shndx = 0;
sym.st_value = 0;
sym.st_size = 0;
symtab_add_raw (&sym);
sym.st_name = 0;
sym.st_info = ELF64_ST_INFO (STB_LOCAL, STT_SECTION);
sym.st_other = STV_DEFAULT;
sym.st_shndx = 1;
sym.st_value = code_start;
sym.st_size = 0;
symtab_add_raw (&sym);
}
void
emit_code_at (uint64_t offset, int size, int64_t val)
{
int64_t orig_val;
int orig_size;
uint8_t *ptr = code + offset;
if (size < 0)
{
size = -size;
val -= code_start + offset + size;
}
orig_val = val;
orig_size = size;
while (size > 0)
{
*ptr++ = val & 0xFF;
val >>= 8;
size -= 1;
}
if (val != 0 && val != -1)
fprintf (stderr, "%s:%d: warning: %ld out of range for %d bytes\n",
in_name, lineno, orig_val, orig_size);
}
void
emit_code (int size, int64_t val)
{
if (code_offset + abs (size) >= code_max)
exitf (1, "too large, congrats");
emit_code_at (code_offset, size, val);
code_offset += abs (size);
}
/* Data
*/
uint64_t data_start;
uint64_t data_offset;
void
init_data ()
{
if (data_start == 0)
data_start = (code_start + code_max + 0xFFF) & ~0xFFF;
data_offset = 0;
}
void
alloc_data (uint64_t size)
{
data_offset += size;
data_offset = (data_offset + 7) & ~7;
}
/* ELF output */
void
dump (const char *out_name)
{
uint64_t str_text = strtab_add (".text");
uint64_t str_strtab = strtab_add (".strtab");
uint64_t str_symtab = strtab_add (".symtab");
uint64_t code_size = code_offset;
uint64_t data_size = data_offset;
uint64_t symtab_offset = sizeof (struct file) + code_size;
uint64_t symtab_size = obstack_object_size (&symtab_obs);
char *symtab = obstack_finish (&symtab_obs);
uint64_t strtab_offset = symtab_offset + symtab_size;
uint64_t strtab_size = obstack_object_size (&strtab_obs);
char *strtab = obstack_finish (&strtab_obs);
struct file f;
memset (f.h.e_ident, 0, sizeof (f.h.e_ident));
f.h.e_ident[EI_MAG0] = ELFMAG0;
f.h.e_ident[EI_MAG1] = ELFMAG1;
f.h.e_ident[EI_MAG2] = ELFMAG2;
f.h.e_ident[EI_MAG3] = ELFMAG3;
f.h.e_ident[EI_CLASS] = ELFCLASS64;
f.h.e_ident[EI_DATA] = ELFDATA2LSB;
f.h.e_ident[EI_VERSION] = EV_CURRENT;
f.h.e_ident[EI_OSABI] = ELFOSABI_NONE;
f.h.e_ident[EI_ABIVERSION] = 0;
f.h.e_type = ET_EXEC;
f.h.e_machine = EM_X86_64;
f.h.e_version = EV_CURRENT;
f.h.e_entry = code_start;
f.h.e_phoff = offsetof (struct file, ph[0]);
f.h.e_shoff = offsetof (struct file, sh[0]);
f.h.e_flags = 0;
f.h.e_ehsize = sizeof (f.h);
f.h.e_phentsize = sizeof (f.ph[0]);
f.h.e_phnum = sizeof (f.ph) / sizeof (f.ph[0]);
f.h.e_shentsize = sizeof (f.sh[0]);
f.h.e_shnum = sizeof (f.sh) / sizeof (f.sh[0]);
f.h.e_shstrndx = 2;
f.ph[0].p_type = PT_LOAD;
f.ph[0].p_flags = PF_X | PF_R;
f.ph[0].p_offset = 0;
f.ph[0].p_vaddr = code_vaddr;
f.ph[0].p_paddr = code_vaddr;
f.ph[0].p_filesz = sizeof(f) + code_size;
f.ph[0].p_memsz = sizeof(f) + code_size;
f.ph[0].p_align = 0;
f.ph[1].p_type = PT_LOAD;
f.ph[1].p_flags = PF_R | PF_W;
f.ph[1].p_offset = 0;
f.ph[1].p_vaddr = data_start;
f.ph[1].p_paddr = data_start;
f.ph[1].p_filesz = 0;
f.ph[1].p_memsz = data_size;
f.ph[1].p_align = 0;
f.sh[0].sh_name = 0;
f.sh[0].sh_type = SHT_NULL;
f.sh[0].sh_flags = 0;
f.sh[0].sh_addr = 0;
f.sh[0].sh_offset = 0;
f.sh[0].sh_size = 0;
f.sh[0].sh_link = 0;
f.sh[0].sh_info = 0;
f.sh[0].sh_addralign = 0;
f.sh[0].sh_entsize = 0;
f.sh[1].sh_name = str_text;
f.sh[1].sh_type = SHT_PROGBITS;
f.sh[1].sh_flags = SHF_ALLOC | SHF_EXECINSTR;
f.sh[1].sh_addr = code_vaddr + sizeof (f);
f.sh[1].sh_offset = sizeof (f);
f.sh[1].sh_size = code_size;
f.sh[1].sh_link = 0;
f.sh[1].sh_info = 0;
f.sh[1].sh_addralign = 4;
f.sh[1].sh_entsize = 0;
f.sh[2].sh_name = str_strtab;
f.sh[2].sh_type = SHT_STRTAB;
f.sh[2].sh_flags = 0;
f.sh[2].sh_addr = 0;
f.sh[2].sh_offset = strtab_offset;
f.sh[2].sh_size = strtab_size;
f.sh[2].sh_link = 0;
f.sh[2].sh_info = 0;
f.sh[2].sh_addralign = 1;
f.sh[2].sh_entsize = 0;
f.sh[3].sh_name = str_symtab;
f.sh[3].sh_type = SHT_SYMTAB;
f.sh[3].sh_flags = 0;
f.sh[3].sh_addr = 0;
f.sh[3].sh_offset = symtab_offset;
f.sh[3].sh_size = symtab_size;
f.sh[3].sh_link = 2;
f.sh[3].sh_info = 2;
f.sh[3].sh_addralign = 8;
f.sh[3].sh_entsize = sizeof (Elf64_Sym);
int fd = creat (out_name, 0777);
if (fd < 0
|| write (fd, &f, sizeof(f)) != sizeof(f)
|| write (fd, code, code_size) != code_size
|| write (fd, symtab, symtab_size) != symtab_size
|| write (fd, strtab, strtab_size) != strtab_size
|| close (fd) < 0)
exitf(1, "%s: %m", out_name);
free (code);
obstack_free (&symtab_obs, NULL);
obstack_free (&strtab_obs, NULL);
}
/* Lists */
typedef struct symdef symdef;
typedef __int128 inum_t;
typedef struct exp {
enum {
pair_exp, sym_exp, string_exp, inum_exp, dnum_exp, singleton_exp
} type;
union {
struct {
struct exp *first;
struct exp *rest;
};
struct {
char *sym;
struct exp *link;
struct symdef *def;
};
inum_t inum;
double dnum;
char *string;
};
} exp;
typedef exp *(*builtin_t)(exp *form);
struct symdef {
enum {
label_symdef, builtin_symdef, macros_symdef
} type;
union {
uint64_t label;
builtin_t builtin;
exp *macros;
};
};
void error (exp *e, const char *msg);
exp nil_obj, eof_obj;
struct obstack exp_obs;
struct obstack symbol_obs;
#define symbol_hash_size 1023
exp *symbol_hash[symbol_hash_size];
void
init_exp ()
{
obstack_init (&exp_obs);
obstack_init (&symbol_obs);
nil_obj.type = eof_obj.type = singleton_exp;
}
void
reset_exp()
{
obstack_free (&exp_obs, NULL);
obstack_init (&exp_obs);
}
void *
alloc_exp_data (size_t n)
{
return obstack_alloc (&exp_obs, n);
}
exp *
alloc_exp ()
{
return alloc_exp_data (sizeof(exp));
}
exp *
nil ()
{
return &nil_obj;
}
bool
is_nil (exp *e)
{
return e == &nil_obj;
}
exp *
end_of_file ()
{
return &eof_obj;
}
bool
is_end_of_file (exp *e)
{
return e == &eof_obj;
}
exp *
cons (exp *first, exp *rest)
{
exp *e = alloc_exp ();
e->type = pair_exp;
e->first = first;
e->rest = rest;
return e;
}
bool
is_pair (exp *e)
{
return e->type == pair_exp;
}
exp *
first (exp *e)
{
return e->first;
}
exp *
rest (exp *e)
{
return e->rest;
}
exp *
second (exp *e)
{
return first (rest (e));
}
exp *
third (exp *e)
{
return first (rest (rest (e)));
}
exp *
inum (inum_t inum)
{
exp *e = alloc_exp ();
e->type = inum_exp;
e->inum = inum;
return e;
}
bool
is_inum (exp *e)
{
return e->type == inum_exp;
}
inum_t
inum_val (exp *e)
{
return e->inum;
}
exp *
dnum (double dnum)
{
exp *e = alloc_exp ();
e->type = dnum_exp;
e->dnum = dnum;
return e;
}
bool
is_dnum (exp *e)
{
return e->type == dnum_exp;
}
double
dnum_val (exp *e)
{
return e->dnum;
}
exp *
sym (const char *sym)
{
unsigned int hash = 5381;
const char *p = sym;
while (*p)
hash = (hash*33) ^ *p++;
hash = hash % symbol_hash_size;
for (exp *e = symbol_hash[hash]; e; e = e->link)
if (strcmp (e->sym, sym) == 0)
return e;
exp *e = alloc_exp ();
e->type = sym_exp;
e->sym = obstack_copy0 (&symbol_obs, sym, strlen (sym));
e->link = symbol_hash[hash];
e->def = NULL;
symbol_hash[hash] = e;
return e;
}
void
sym_foreach (void (*func) (exp *sym))
{
for (int i = 0; i < symbol_hash_size; i++)
for (exp *e = symbol_hash[i]; e; e = e->link)
func (e);
}
bool
is_sym (exp *e)
{
return e && e->type == sym_exp;
}
char *
sym_name (exp *e)
{
return e->sym;
}
exp *
gensym (char *tag)
{
static int counter;
char name[80];
snprintf(name, 80, "%d-%s", counter++, tag? tag : "gensym");
return sym(name);
}
void
sym_undef (exp *e)
{
e->def = NULL;
}
void
sym_def_builtin (exp *e, builtin_t builtin)
{
if (e->def)
error (e, "redefined");
symdef *d = alloc_exp_data (sizeof (symdef));
d->type = builtin_symdef;
d->builtin = builtin;
e->def = d;
}
bool
sym_is_builtin (exp *e)
{
return e->def && e->def->type == builtin_symdef;
}
builtin_t
sym_builtin (exp *e)
{
return e->def->builtin;
}
void
sym_def_label (exp *e, uint64_t label)
{
if (e->def)
error (e, "redefined");
symdef *d = alloc_exp_data (sizeof (symdef));
d->type = label_symdef;
d->label = label;
e->def = d;
}
bool
sym_is_label (exp *e)
{
return e->def && e->def->type == label_symdef;
}
uint64_t
sym_label (exp *e)
{
return e->def->label;
}
void
sym_def_add_macro (exp *e, exp *macro)
{
if (e->def == NULL)
{
symdef *d = alloc_exp_data (sizeof (symdef));
d->type = macros_symdef;
d->macros = nil ();
e->def = d;
}
else if (e->def->type != macros_symdef)
error (e, "redefined");
e->def->macros = cons (macro, e->def->macros);
}
bool
sym_is_macros (exp *e)
{
return e->def && e->def->type == macros_symdef;
}
exp *
sym_macros (exp *e)
{
return e->def->macros;
}
exp *
string (char *str)
{
exp *e = alloc_exp ();
e->type = string_exp;
e->string = alloc_exp_data (strlen (str) + 1);
strcpy (e->string, str);
return e;
}
bool
is_string (exp *e)
{
return e && e->type == string_exp;
}
char *
string_chars (exp *e)
{
return e->string;
}
exp *
reverse_onto (exp *e, exp *tail)
{
exp *r = tail;
while (is_pair (e))
{
exp *n = e->rest;
e->rest = r;
r = e;
e = n;
}
return r;
}
exp *
reverse (exp *e)
{
return reverse_onto (e, nil ());
}
int
len (exp *e)
{
int l = 0;
while (is_pair (e))
{
e = rest (e);
l += 1;
}
return l;
}
/* Reading and writing */
void
write_exp (FILE *f, exp *e)
{
if (is_sym (e))
{
// XXX - escape things properly
fprintf (f, "%s", sym_name (e));
}
else if (is_string (e))
{
// XXX - escape things properly
fprintf (f, "\"%s\"", string_chars (e));
}
else if (is_inum (e))
{
inum_t val = inum_val(e);
if (val >= LONG_MIN && val <= LONG_MAX)
fprintf (f, "%ld", (long)val);
else if (val >= 0 && val <= ULONG_MAX)
fprintf (f, "%lu", (unsigned long)val);
else
fprintf (f, "<out-of-range>");
}
else if (is_dnum (e))
{
fprintf (f, "%g", dnum_val(e));
}
else if (is_nil (e) || is_pair (e))
{
bool need_space = false;
fprintf (f, "(");
while (is_pair (e))
{
if (need_space)
fprintf (f, " ");
write_exp (f, e->first);
e = e->rest;
need_space = true;
}
if (!is_nil (e))
{
fprintf (f, " . ");
write_exp (f, e);
}
fprintf (f, ")");
}
else if (is_end_of_file (e))
fprintf (f, "<eof>");
else
fprintf (f, "<?>");
}
FILE *in_file;
bool at_bol;
void
read_open (const char *name)
{
in_name = name;
in_file = fopen (in_name, "r");
lineno = 1;
if (in_file == NULL)
exitf (1, "%s: %m", in_name);
at_bol = true;
}
void
read_close ()
{
fclose (in_file);
}
#define token_size 1024
char token[token_size];
enum { punct_tok, sym_tok, string_tok, inum_tok, dnum_tok, eof_tok } token_kind;
int
isdelimiter (int c)
{
return isspace (c) || c == '(' || c == ')';
}
int
isnumstartchar (int c)
{
return isdigit (c) || c == '-';
}
int
isnumrestchar (int c)
{
return (isdigit (c) || c == '.' || c == 'x' ||
(c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F'));
}
void
read_token ()
{
token[0] = '\0';
int c;
again:
while (isspace (c = fgetc (in_file)))
{
if (c == '\n')
{
lineno++;
at_bol = true;
}
else
at_bol = false;
}
if (c == '@' && at_bol)
{
again_section:
c = fgetc (in_file);
at_bol = false;
if (c == '=')
goto again;
while (!(c== '@' && at_bol))
{
if (c == '\n')
{
lineno++;
at_bol = true;
}
else
at_bol = false;
c = fgetc (in_file);
if (c == EOF)
break;
}
if (c != EOF)
goto again_section;
}
if (c == ';')
{
while ((c = fgetc (in_file)) != '\n')
;
lineno++;
goto again;
}
if (c == '(' || c == ')')
{
token[0] = c;
token[1] = '\0';
token_kind = punct_tok;
}
else if (c == '\'' || c == '"')
{
char quote = c;
bool escape_next = false;
int i = 0;
while ((c = fgetc (in_file)) != EOF && (c != quote || escape_next))
{
if (c == '\n')
lineno++;
if (c == '\\' && !escape_next)
escape_next = true;
else
{
if (escape_next)
{
switch (c) {
case 'n':
c = '\n';
break;
case '"':
c = '"';
break;
default:
exitf (1, "unknown string escape '%c'", c);
break;
}
}
token[i++] = c;
escape_next = false;
}
}
token[i] = '\0';
token_kind = (quote == '\''? sym_tok : string_tok);
}
else if (c != EOF)
{
int i = 0;
token_kind = inum_tok;
while (c != EOF && !isdelimiter (c))
{
if (!((i == 0)? isnumstartchar (c) : isnumrestchar (c)))
token_kind = sym_tok;
if (c == '.' && token_kind == inum_tok)
token_kind = dnum_tok;
token[i++] = c;
c = fgetc (in_file);
}
token[i] = '\0';
ungetc (c, in_file);
if (strcmp (token, "-") == 0)
token_kind = sym_tok;
}
else
token_kind = eof_tok;
}
inum_t
strtoinum (const char *str)
{
const char *ptr = str;
int base = 10;
int sign = 1;
inum_t val;
if (ptr[0] == '-')
{
sign = -1;
ptr += 1;
}
if (ptr[0] == '0' && ptr[1] == 'x')
{
base = 16;
ptr += 2;
}
val = 0;
while (*ptr)
{
int digit;
if (base == 16 && *ptr >= 'a' && *ptr <= 'f')
digit = 10 + *ptr - 'a';
else if (base == 16 && *ptr >= 'A' && *ptr <= 'F')
digit = 10 + *ptr - 'A';
else if (*ptr >= '0' && *ptr <= '9')
digit = *ptr - '0';
else
exitf(0, "invalid number %s", str);
val = val*base + digit;
ptr++;
}
return sign*val;
}
exp *
read_exp_1 ()
{
if (token_kind == eof_tok)
return end_of_file ();
else if (token_kind == inum_tok)
return inum (strtoinum (token));
else if (token_kind == dnum_tok)
return dnum (strtod (token, NULL));
else if (token_kind == sym_tok)
return sym (token);
else if (token_kind == string_tok)
return string (token);
else if (token_kind == punct_tok && token[0] == '(')
{
exp *e = nil ();
while (true) {
read_token ();
if (token_kind == punct_tok && token[0] == ')')
return reverse (e);
else if (token_kind == sym_tok && strcmp (token, ".") == 0)
{
read_token ();
e = reverse_onto (e, read_exp_1 ());
read_token ();
if (token_kind != punct_tok || token[0] != ')')
exitf(1, "junk after tail: %s", token);
return e;
}
else if (token_kind == eof_tok)
exitf (1, "unterminated list");
e = cons (read_exp_1 (), e);
}
}
else
exitf(1, "%d: unexpected token '%s'", lineno, token);
}
exp *
read_exp ()
{
read_token ();
return read_exp_1 ();
}
void
error (exp *form, const char *msg)
{
fprintf (stderr, "%s:%d: ", in_name, lineno);
write_exp (stderr, form);
fprintf (stderr, "\n");
exitf (1, "error: %s", msg);
}
bool
is_form (exp *e, const char *sym)
{
return (is_pair (e) &&