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efl/src/bin/embryo/embryo_cc_sc7.c

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/* Small compiler - Staging buffer and optimizer
*
* The staging buffer
* ------------------
* The staging buffer allows buffered output of generated code, deletion
* of redundant code, optimization by a tinkering process and reversing
* the ouput of evaluated expressions (which is used for the reversed
* evaluation of arguments in functions).
* Initially, stgwrite() writes to the file directly, but after a call to
* stgset(TRUE), output is redirected to the buffer. After a call to
* stgset(FALSE), stgwrite()'s output is directed to the file again. Thus
* only one routine is used for writing to the output, which can be
* buffered output or direct output.
*
* staging buffer variables: stgbuf - the buffer
* stgidx - current index in the staging buffer
* staging - if true, write to the staging buffer;
* if false, write to file directly.
*
* Copyright (c) ITB CompuPhase, 1997-2003
*
* This software is provided "as-is", without any express or implied warranty.
* In no event will the authors be held liable for any damages arising from
* the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software in
* a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*
* Version: $Id$
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <assert.h>
#include <stdio.h>
#include <stdlib.h> /* for atoi() */
#include <string.h>
#include <ctype.h>
#include "embryo_cc_sc.h"
#if defined _MSC_VER
#pragma warning(push)
#pragma warning(disable:4125) /* decimal digit terminates octal escape sequence */
#endif
#include "embryo_cc_sc7.scp"
#if defined _MSC_VER
#pragma warning(pop)
#endif
static void stgstring(char *start, char *end);
static void stgopt(char *start, char *end);
#define sSTG_GROW 512
#define sSTG_MAX 20480
static char *stgbuf = NULL;
static int stgmax = 0; /* current size of the staging buffer */
#define CHECK_STGBUFFER(index) if ((int)(index)>=stgmax) grow_stgbuffer((index)+1)
static void
grow_stgbuffer(int requiredsize)
{
char *p;
int clear = !stgbuf; /* if previously none, empty buffer explicitly */
assert(stgmax < requiredsize);
/* if the staging buffer (holding intermediate code for one line) grows
* over a few kBytes, there is probably a run-away expression
*/
if (requiredsize > sSTG_MAX)
error(102, "staging buffer"); /* staging buffer overflow (fatal error) */
stgmax = requiredsize + sSTG_GROW;
if (stgbuf)
p = (char *)realloc(stgbuf, stgmax * sizeof(char));
else
p = (char *)malloc(stgmax * sizeof(char));
if (!p)
error(102, "staging buffer"); /* staging buffer overflow (fatal error) */
stgbuf = p;
if (clear)
*stgbuf = '\0';
}
void
stgbuffer_cleanup(void)
{
if (stgbuf)
{
free(stgbuf);
stgbuf = NULL;
stgmax = 0;
} /* if */
}
/* the variables "stgidx" and "staging" are declared in "scvars.c" */
/* stgmark
*
* Copies a mark into the staging buffer. At this moment there are three
* possible marks:
* sSTARTREORDER identifies the beginning of a series of expression
* strings that must be written to the output file in
* reordered order
* sENDREORDER identifies the end of 'reverse evaluation'
* sEXPRSTART + idx only valid within a block that is evaluated in
* reordered order, it identifies the start of an
* expression; the "idx" value is the argument position
*
* Global references: stgidx (altered)
* stgbuf (altered)
* staging (referred to only)
*/
void
stgmark(char mark)
{
if (staging)
{
CHECK_STGBUFFER(stgidx);
stgbuf[stgidx++] = mark;
} /* if */
}
static int
filewrite(char *str)
{
if (sc_status == statWRITE)
return sc_writeasm(outf, str);
return TRUE;
}
/* stgwrite
*
* Writes the string "st" to the staging buffer or to the output file. In the
* case of writing to the staging buffer, the terminating byte of zero is
* copied too, but... the optimizer can only work on complete lines (not on
* fractions of it. Therefore if the string is staged, if the last character
* written to the buffer is a '\0' and the previous-to-last is not a '\n',
* the string is concatenated to the last string in the buffer (the '\0' is
* overwritten). This also means an '\n' used in the middle of a string isn't
* recognized and could give wrong results with the optimizer.
* Even when writing to the output file directly, all strings are buffered
* until a whole line is complete.
*
* Global references: stgidx (altered)
* stgbuf (altered)
* staging (referred to only)
*/
void
stgwrite(char *st)
{
int len;
CHECK_STGBUFFER(0);
if (staging)
{
if (stgidx >= 2 && stgbuf[stgidx - 1] == '\0'
&& stgbuf[stgidx - 2] != '\n')
stgidx -= 1; /* overwrite last '\0' */
while (*st != '\0')
{ /* copy to staging buffer */
CHECK_STGBUFFER(stgidx);
stgbuf[stgidx++] = *st++;
} /* while */
CHECK_STGBUFFER(stgidx);
stgbuf[stgidx++] = '\0';
}
else
{
CHECK_STGBUFFER(strlen(stgbuf) + strlen(st) + 1);
strcat(stgbuf, st);
len = strlen(stgbuf);
if (len > 0 && stgbuf[len - 1] == '\n')
{
filewrite(stgbuf);
stgbuf[0] = '\0';
} /* if */
} /* if */
}
/* stgout
*
* Writes the staging buffer to the output file via stgstring() (for
* reversing expressions in the buffer) and stgopt() (for optimizing). It
* resets "stgidx".
*
* Global references: stgidx (altered)
* stgbuf (referred to only)
* staging (referred to only)
*/
void
stgout(int idx)
{
if (!staging)
return;
stgstring(&stgbuf[idx], &stgbuf[stgidx]);
stgidx = idx;
}
typedef struct
{
char *start, *end;
} argstack;
/* stgstring
*
* Analyses whether code strings should be output to the file as they appear
* in the staging buffer or whether portions of it should be re-ordered.
* Re-ordering takes place in function argument lists; Small passes arguments
* to functions from right to left. When arguments are "named" rather than
* positional, the order in the source stream is indeterminate.
* This function calls itself recursively in case it needs to re-order code
* strings, and it uses a private stack (or list) to mark the start and the
* end of expressions in their correct (reversed) order.
* In any case, stgstring() sends a block as large as possible to the
* optimizer stgopt().
*
* In "reorder" mode, each set of code strings must start with the token
* sEXPRSTART, even the first. If the token sSTARTREORDER is represented
* by '[', sENDREORDER by ']' and sEXPRSTART by '|' the following applies:
* '[]...' valid, but useless; no output
* '[|...] valid, but useless; only one string
* '[|...|...] valid and useful
* '[...|...] invalid, first string doesn't start with '|'
* '[|...|] invalid
*/
static void
stgstring(char *start, char *end)
{
char *ptr;
int nest, argc, arg;
argstack *stack;
while (start < end)
{
if (*start == sSTARTREORDER)
{
start += 1; /* skip token */
/* allocate a argstack with sMAXARGS items */
stack = (argstack *) malloc(sMAXARGS * sizeof(argstack));
if (!stack)
error(103); /* insufficient memory */
nest = 1; /* nesting counter */
argc = 0; /* argument counter */
arg = -1; /* argument index; no valid argument yet */
do
{
switch (*start)
{
case sSTARTREORDER:
nest++;
start++;
break;
case sENDREORDER:
nest--;
start++;
break;
default:
if ((*start & sEXPRSTART) == sEXPRSTART)
{
if (nest == 1)
{
if (arg >= 0)
stack[arg].end = start - 1; /* finish previous argument */
arg = (unsigned char)*start - sEXPRSTART;
stack[arg].start = start + 1;
if (arg >= argc)
argc = arg + 1;
} /* if */
start++;
}
else
{
start += strlen(start) + 1;
} /* if */
} /* switch */
}
while (nest); /* enddo */
if (arg >= 0)
stack[arg].end = start - 1; /* finish previous argument */
while (argc > 0)
{
argc--;
stgstring(stack[argc].start, stack[argc].end);
} /* while */
free(stack);
}
else
{
ptr = start;
while (ptr < end && *ptr != sSTARTREORDER)
ptr += strlen(ptr) + 1;
stgopt(start, ptr);
start = ptr;
} /* if */
} /* while */
}
/* stgdel
*
* Scraps code from the staging buffer by resetting "stgidx" to "index".
*
* Global references: stgidx (altered)
* staging (referred to only)
*/
void
stgdel(int idx, cell code_index)
{
if (staging)
{
stgidx = idx;
code_idx = code_index;
} /* if */
}
int
stgget(int *idx, cell * code_index)
{
if (staging)
{
*idx = stgidx;
*code_index = code_idx;
} /* if */
return staging;
}
/* stgset
*
* Sets staging on or off. If it's turned off, the staging buffer must be
* initialized to an empty string. If it's turned on, the routine makes sure
* the index ("stgidx") is set to 0 (it should already be 0).
*
* Global references: staging (altered)
* stgidx (altered)
* stgbuf (contents altered)
*/
void
stgset(int onoff)
{
staging = onoff;
if (staging)
{
assert(stgidx == 0);
stgidx = 0;
CHECK_STGBUFFER(stgidx);
/* write any contents that may be put in the buffer by stgwrite()
* when "staging" was 0
*/
if (stgbuf[0] != '\0')
filewrite(stgbuf);
} /* if */
stgbuf[0] = '\0';
}
/* phopt_init
* Initialize all sequence strings of the peehole optimizer. The strings
* are embedded in the .EXE file in compressed format, here we expand
* them (and allocate memory for the sequences).
*/
static SEQUENCE *sequences;
int
phopt_init(void)
{
int number, i, len;
char str[160];
/* count number of sequences */
for (number = 0; sequences_cmp[number].find; number++)
/* nothing */ ;
number++; /* include an item for the NULL terminator */
if (!(sequences = (SEQUENCE *)malloc(number * sizeof(SEQUENCE))))
return FALSE;
/* pre-initialize all to NULL (in case of failure) */
for (i = 0; i < number; i++)
{
sequences[i].find = NULL;
sequences[i].replace = NULL;
sequences[i].savesize = 0;
} /* for */
/* expand all strings */
for (i = 0; i < number - 1; i++)
{
len =
strexpand(str, (unsigned char *)sequences_cmp[i].find, sizeof str,
SCPACK_TABLE);
assert(len <= (int)(sizeof(str)));
assert(len == (int)(strlen(str) + 1));
sequences[i].find = (char *)malloc(len);
if (sequences[i].find)
strcpy(sequences[i].find, str);
len =
strexpand(str, (unsigned char *)sequences_cmp[i].replace, sizeof str,
SCPACK_TABLE);
assert(len <= (int)(sizeof(str)));
assert(len == (int)(strlen(str) + 1));
sequences[i].replace = (char *)malloc(len);
if (sequences[i].replace)
strcpy(sequences[i].replace, str);
sequences[i].savesize = sequences_cmp[i].savesize;
if (!sequences[i].find || !sequences[i].replace)
return phopt_cleanup();
} /* for */
return TRUE;
}
int
phopt_cleanup(void)
{
int i;
if (sequences)
{
i = 0;
while (sequences[i].find || sequences[i].replace)
{
if (sequences[i].find)
free(sequences[i].find);
if (sequences[i].replace)
free(sequences[i].replace);
i++;
} /* while */
free(sequences);
sequences = NULL;
} /* if */
return FALSE;
}
#define _maxoptvars 4
#define _aliasmax 10 /* a 32-bit number can be represented in
* 9 decimal digits */
static int
matchsequence(char *start, char *end, char *pattern,
char symbols[_maxoptvars][_aliasmax + 1], int *match_length)
{
int var, i;
char str[_aliasmax + 1];
char *start_org = start;
*match_length = 0;
for (var = 0; var < _maxoptvars; var++)
symbols[var][0] = '\0';
while (*start == '\t' || *start == ' ')
start++;
while (*pattern)
{
if (start >= end)
return FALSE;
switch (*pattern)
{
case '%': /* new "symbol" */
pattern++;
assert(sc_isdigit(*pattern));
var = atoi(pattern) - 1;
assert(var >= 0 && var < _maxoptvars);
assert(alphanum(*start));
for (i = 0; start < end && alphanum(*start); i++, start++)
{
assert(i <= _aliasmax);
str[i] = *start;
} /* for */
str[i] = '\0';
if (symbols[var][0] != '\0')
{
if (strcmp(symbols[var], str) != 0)
return FALSE; /* symbols should be identical */
}
else
{
strcpy(symbols[var], str);
} /* if */
break;
case ' ':
if (*start != '\t' && *start != ' ')
return FALSE;
while ((start < end && *start == '\t') || *start == ' ')
start++;
break;
case '!':
while ((start < end && *start == '\t') || *start == ' ')
start++; /* skip trailing white space */
if (*start != '\n')
return FALSE;
assert(*(start + 1) == '\0');
start += 2; /* skip '\n' and '\0' */
if (*(pattern + 1) != '\0')
while ((start < end && *start == '\t') || *start == ' ')
start++; /* skip leading white space of next instruction */
break;
default:
if (tolower(*start) != tolower(*pattern))
return FALSE;
start++;
} /* switch */
pattern++;
} /* while */
*match_length = (int)(start - start_org);
return TRUE;
}
static char *
replacesequence(char *pattern, char symbols[_maxoptvars][_aliasmax + 1],
int *repl_length)
{
char *lptr;
int var;
char *buffer;
/* calculate the length of the new buffer
* this is the length of the pattern plus the length of all symbols (note
* that the same symbol may occur multiple times in the pattern) plus
* line endings and startings ('\t' to start a line and '\n\0' to end one)
*/
assert(repl_length != NULL);
*repl_length = 0;
lptr = pattern;
while (*lptr)
{
switch (*lptr)
{
case '%':
lptr++; /* skip '%' */
assert(sc_isdigit(*lptr));
var = atoi(lptr) - 1;
assert(var >= 0 && var < _maxoptvars);
assert(symbols[var][0] != '\0'); /* variable should be defined */
*repl_length += strlen(symbols[var]);
break;
case '!':
*repl_length += 3; /* '\t', '\n' & '\0' */
break;
default:
*repl_length += 1;
} /* switch */
lptr++;
} /* while */
/* allocate a buffer to replace the sequence in */
if (!(buffer = malloc(*repl_length)))
{
error(103);
return NULL;
}
/* replace the pattern into this temporary buffer */
lptr = buffer;
*lptr++ = '\t'; /* the "replace" patterns do not have tabs */
while (*pattern)
{
assert((int)(lptr - buffer) < *repl_length);
switch (*pattern)
{
case '%':
/* write out the symbol */
pattern++;
assert(sc_isdigit(*pattern));
var = atoi(pattern) - 1;
assert(var >= 0 && var < _maxoptvars);
assert(symbols[var][0] != '\0'); /* variable should be defined */
strcpy(lptr, symbols[var]);
lptr += strlen(symbols[var]);
break;
case '!':
/* finish the line, optionally start the next line with an indent */
*lptr++ = '\n';
*lptr++ = '\0';
if (*(pattern + 1) != '\0')
*lptr++ = '\t';
break;
default:
*lptr++ = *pattern;
} /* switch */
pattern++;
} /* while */
assert((int)(lptr - buffer) == *repl_length);
return buffer;
}
static void
strreplace(char *dest, char *replace, int sub_length, int repl_length,
int dest_length)
{
int offset = sub_length - repl_length;
if (offset > 0) /* delete a section */
memmove(dest, dest + offset, dest_length - offset);
else if (offset < 0) /* insert a section */
memmove(dest - offset, dest, dest_length);
memcpy(dest, replace, repl_length);
}
/* stgopt
*
* Optimizes the staging buffer by checking for series of instructions that
* can be coded more compact. The routine expects the lines in the staging
* buffer to be separated with '\n' and '\0' characters.
*
* The longest sequences must be checked first.
*/
static void
stgopt(char *start, char *end)
{
char symbols[_maxoptvars][_aliasmax + 1];
int seq, match_length, repl_length;
assert(sequences != NULL);
while (start < end)
{
if ((sc_debug & sNOOPTIMIZE) != 0 || sc_status != statWRITE)
{
/* do not match anything if debug-level is maximum */
filewrite(start);
}
else
{
seq = 0;
while (sequences[seq].find)
{
assert(seq >= 0);
if (matchsequence
(start, end, sequences[seq].find, symbols, &match_length))
{
char *replace =
replacesequence(sequences[seq].replace, symbols,
&repl_length);
/* If the replacement is bigger than the original section, we may need
* to "grow" the staging buffer. This is quite complex, due to the
* re-ordering of expressions that can also happen in the staging
* buffer. In addition, it should not happen: the peephole optimizer
* must replace sequences with *shorter* sequences, not longer ones.
* So, I simply forbid sequences that are longer than the ones they
* are meant to replace.
*/
assert(match_length >= repl_length);
if (match_length >= repl_length)
{
strreplace(start, replace, match_length,
repl_length, (int)(end - start));
end -= match_length - repl_length;
free(replace);
code_idx -= sequences[seq].savesize;
seq = 0; /* restart search for matches */
}
else
{
/* actually, we should never get here (match_length<repl_length) */
assert(0);
seq++;
} /* if */
}
else
{
seq++;
} /* if */
} /* while */
assert(sequences[seq].find == NULL);
filewrite(start);
} /* if */
assert(start < end);
start += strlen(start) + 1; /* to next string */
} /* while (start<end) */
}
#undef SCPACK_TABLE