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optimization: Introduce new flag to turn-off selectively

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While configuring optimization in a level is conventional,
a certain optimization tends to conflict with some pragma.

For example, jump match conflicts with Mach-O's
"subsections-via-symbols" macro.

This configurability will workaround such conflicts.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
This commit is contained in:
Chang S. Bae 2018-08-15 23:22:21 +03:00 committed by Cyrill Gorcunov
parent ccd2d5c542
commit a578634b61
5 changed files with 35 additions and 18 deletions
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6
asm/assemble.c
View File

@ -528,9 +528,9 @@ static bool jmp_match(int32_t segment, int64_t offset, int bits,
if (((c & ~1) != 0370) || (ins->oprs[0].type & STRICT))
return false;
if (!optimizing)
if (!optimizing.level || (optimizing.flag & OPTIM_DISABLE_JMP_MATCH))
return false;
if (optimizing < 0 && c == 0371)
if (optimizing.level < 0 && c == 0371)
return false;
isize = calcsize(segment, offset, bits, ins, temp);
@ -2188,7 +2188,7 @@ static enum match_result matches(const struct itemplate *itemp,
/*
* Is it legal?
*/
if (!(optimizing > 0) && itemp_has(itemp, IF_OPT))
if (!(optimizing.level > 0) && itemp_has(itemp, IF_OPT))
return MERR_INVALOP;
/*

21
asm/nasm.c
View File

@ -117,7 +117,8 @@ const struct dfmt *dfmt;
static FILE *error_file; /* Where to write error messages */
FILE *ofile = NULL;
int optimizing = MAX_OPTIMIZE; /* number of optimization passes to take */
struct optimization optimizing =
{ MAX_OPTIMIZE, OPTIM_ALL_ENABLED }; /* number of optimization passes to take */
static int cmd_sb = 16; /* by default */
iflag_t cpu;
@ -867,7 +868,7 @@ static bool process_arg(char *p, char *q, int pass)
if (!*param) {
/* Naked -O == -Ox */
optimizing = MAX_OPTIMIZE;
optimizing.level = MAX_OPTIMIZE;
} else {
while (*param) {
switch (*param) {
@ -875,12 +876,12 @@ static bool process_arg(char *p, char *q, int pass)
case '5': case '6': case '7': case '8': case '9':
opt = strtoul(param, &param, 10);
/* -O0 -> optimizing == -1, 0.98 behaviour */
/* -O1 -> optimizing == 0, 0.98.09 behaviour */
/* -O0 -> optimizing.level == -1, 0.98 behaviour */
/* -O1 -> optimizing.level == 0, 0.98.09 behaviour */
if (opt < 2)
optimizing = opt - 1;
optimizing.level = opt - 1;
else
optimizing = opt;
optimizing.level = opt;
break;
case 'v':
@ -891,7 +892,7 @@ static bool process_arg(char *p, char *q, int pass)
case 'x':
param++;
optimizing = MAX_OPTIMIZE;
optimizing.level = MAX_OPTIMIZE;
break;
default:
@ -901,8 +902,8 @@ static bool process_arg(char *p, char *q, int pass)
break;
}
}
if (optimizing > MAX_OPTIMIZE)
optimizing = MAX_OPTIMIZE;
if (optimizing.level > MAX_OPTIMIZE)
optimizing.level = MAX_OPTIMIZE;
}
}
break;
@ -1448,7 +1449,7 @@ static void assemble_file(const char *fname, StrList **depend_ptr)
/* Not a directive, or even something that starts with [ */
parse_line(pass1, line, &output_ins);
if (optimizing > 0) {
if (optimizing.level > 0) {
if (forwref != NULL && globallineno == forwref->lineno) {
output_ins.forw_ref = true;
do {

4
asm/parser.c
View File

@ -1028,7 +1028,7 @@ is_expression:
op->segment = NO_SEG; /* don't care again */
op->wrt = NO_SEG; /* still don't care */
if(optimizing >= 0 && !(op->type & STRICT)) {
if(optimizing.level >= 0 && !(op->type & STRICT)) {
/* Be optimistic */
op->type |=
UNITY | SBYTEWORD | SBYTEDWORD | UDWORD | SDWORD;
@ -1045,7 +1045,7 @@ is_expression:
if (is_simple(value)) {
if (n == 1)
op->type |= UNITY;
if (optimizing >= 0 && !(op->type & STRICT)) {
if (optimizing.level >= 0 && !(op->type & STRICT)) {
if ((uint32_t) (n + 128) <= 255)
op->type |= SBYTEDWORD;
if ((uint16_t) (n + 128) <= 255)

6
doc/opt_var.txt
View File

@ -6,7 +6,8 @@
GLOBAL variables:
optimizing -1 flags nasm 0.98 compatible operation;
optimizing optimization meta data (with level and flag info)
.level -1 flags nasm 0.98 compatible operation;
offsets usually are explicit (short/near)
no optimization passes
0 flags non-optimized assembly; forward
@ -17,7 +18,8 @@ GLOBAL variables:
the actual recommended minimum setting
optimization passes (2 or more, plus
passes 1 and 2 will be required)
.flag 0 allow all optimizations
1 disallow jump match optimization
pass0 0 flags an optimizer pass (multiple passes)
1 flags pass1 (define labels)

16
include/nasm.h
View File

@ -1248,11 +1248,25 @@ enum decorator_tokens {
* 2 = pass 2
*/
/*
* flag to disable optimizations selectively
* this is useful to turn-off certain optimizations
*/
enum optimization_disable_flag {
OPTIM_ALL_ENABLED = 0,
OPTIM_DISABLE_JMP_MATCH = 1
};
struct optimization {
int level;
int flag;
};
extern int pass0;
extern int64_t passn; /* Actual pass number */
extern bool tasm_compatible_mode;
extern int optimizing;
extern struct optimization optimizing;
extern int globalbits; /* 16, 32 or 64-bit mode */
extern int globalrel; /* default to relative addressing? */
extern int globalbnd; /* default to using bnd prefix? */