* acconfig.h (HAVE_GAS_MAX_SKIP_P2ALIGN): New tag.
* configure.in: Check for it.
* i386/gas.h (ASM_OUTPUT_MAX_SKIP_ALIGN): Use it.
* final.c (uid_align, uid_shuid, label_align): Make static.
(label_align): Change type to struct label_alignment pointer.
(LABEL_TO_ALIGNMENT, shorten_branches): Update due to type change.
(LABEL_TO_MAX_SKIP): Define.
(LABEL_ALIGN_MAX_SKIP, LOOP_ALIGN_MAX_SKIP,
LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP): Provide defaults.
(shorten_branches): Record the maximum bytes to skip when
aligning a label.
(final_scan_insn): Use the maximum bytes to skip when aligning a label
if ASM_OUTPUT_MAX_SKIP_ALIGN is available.
* i386.h (LOOP_ALIGN_MAX_SKIP,
LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP): Define.
* i386.c (override_options): i386_align_jumps and i386_align_loops
default to 4 if ASM_OUTPUT_MAX_SKIP_ALIGN is available.
* invoke.texi: Document new i386 align-loops and align-jumps behavior.
From-SVN: r19933
+Wed May 20 23:44:28 EDT 1998 John Wehle (john@feith.com)
+
+ * acconfig.h (HAVE_GAS_MAX_SKIP_P2ALIGN): New tag.
+ * configure.in: Check for it.
+ * i386/gas.h (ASM_OUTPUT_MAX_SKIP_ALIGN): Use it.
+ * final.c (uid_align, uid_shuid, label_align): Make static.
+ (label_align): Change type to struct label_alignment pointer.
+ (LABEL_TO_ALIGNMENT, shorten_branches): Update due to type change.
+ (LABEL_TO_MAX_SKIP): Define.
+ (LABEL_ALIGN_MAX_SKIP, LOOP_ALIGN_MAX_SKIP,
+ LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP): Provide defaults.
+ (shorten_branches): Record the maximum bytes to skip when
+ aligning a label.
+ (final_scan_insn): Use the maximum bytes to skip when aligning a label
+ if ASM_OUTPUT_MAX_SKIP_ALIGN is available.
+ * i386.h (LOOP_ALIGN_MAX_SKIP,
+ LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP): Define.
+ * i386.c (override_options): i386_align_jumps and i386_align_loops
+ default to 4 if ASM_OUTPUT_MAX_SKIP_ALIGN is available.
+ * invoke.texi: Document new i386 align-loops and align-jumps behavior.
+
1998-05-21 Mark Mitchell <mmitchell@usa.net>
* cplus-dem.c (do_type): Handle volatile qualification.
/* Define if your compiler understands volatile. */
#undef HAVE_VOLATILE
+/* Define if your assembler supports specifying the maximum number
+ of bytes to skip when using the GAS .p2align command. */
+#undef HAVE_GAS_MAX_SKIP_P2ALIGN
+
/* Define if you have a working <inttypes.h> header file. */
#undef HAVE_INTTYPES_H
/* Define if your compiler understands volatile. */
#undef HAVE_VOLATILE
+/* Define if your assembler supports specifying the maximum number
+ of bytes to skip when using the GAS .p2align command. */
+#undef HAVE_GAS_MAX_SKIP_P2ALIGN
+
/* Define if you have a working <inttypes.h> header file. */
#undef HAVE_INTTYPES_H
#define ASM_OUTPUT_ALIGN(FILE,LOG) \
if ((LOG)!=0) fprintf ((FILE), "\t.balign %d\n", 1<<(LOG))
#endif
+
+/* A C statement to output to the stdio stream FILE an assembler
+ command to advance the location counter to a multiple of 1<<LOG
+ bytes if it is within MAX_SKIP bytes.
+
+ This is used to align code labels according to Intel recommendations. */
+
+#ifdef HAVE_GAS_MAX_SKIP_P2ALIGN
+# define ASM_OUTPUT_MAX_SKIP_ALIGN(FILE,LOG,MAX_SKIP) \
+ if ((LOG)!=0) \
+ if ((MAX_SKIP)==0) fprintf ((FILE), "\t.p2align %d\n", (LOG)); \
+ else fprintf ((FILE), "\t.p2align %d,,%d\n", (LOG), (MAX_SKIP))
+#endif
\f
/* A C statement or statements which output an assembler instruction
opcode to the stdio stream STREAM. The macro-operand PTR is a
i386_align_loops, MAX_CODE_ALIGN);
}
else
+#ifdef ASM_OUTPUT_MAX_SKIP_ALIGN
+ i386_align_loops = 4;
+#else
i386_align_loops = 2;
+#endif
/* Validate -malign-jumps= value, or provide default. */
if (i386_align_jumps_string)
i386_align_jumps, MAX_CODE_ALIGN);
}
else
+#ifdef ASM_OUTPUT_MAX_SKIP_ALIGN
+ i386_align_jumps = 4;
+#else
i386_align_jumps = def_align;
+#endif
/* Validate -malign-functions= value, or provide default. */
if (i386_align_funcs_string)
/* Align loop starts for optimal branching. */
#define LOOP_ALIGN(LABEL) (i386_align_loops)
+#define LOOP_ALIGN_MAX_SKIP (i386_align_loops_string ? 0 : 7)
/* This is how to align an instruction for optimal branching.
On i486 we'll get better performance by aligning on a
cache line (i.e. 16 byte) boundary. */
#define LABEL_ALIGN_AFTER_BARRIER(LABEL) (i386_align_jumps)
+#define LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP (i386_align_jumps_string ? 0 : 7)
\f
/* Standard register usage. */
# fi
fi
+# Figure out what assembler alignment features are present.
+echo $ac_n "checking assembler alignment features""... $ac_c" 1>&6
+echo "configure:5076: checking assembler alignment features" >&5
+gcc_cv_as=
+gcc_cv_as_alignment_features=
+if [ -x as$host_exeext ]; then
+ # Build using assembler in the current directory.
+ gcc_cv_as=./as$host_exeext
+elif [ -f $srcdir/../gas/configure.in ]; then
+ # Single tree build which includes gas.
+ for f in $srcdir/../gas/configure.in $srcdir/../gas/Makefile.in
+ do
+ gcc_cv_gas_version=`grep '^VERSION=[0-9]*\.[0-9]*' $f`
+ if [ x$gcc_cv_gas_version != x ]; then
+ break
+ fi
+ done
+ gcc_cv_gas_major_version=`expr "$gcc_cv_gas_version" : "VERSION=\([0-9]*\)"`
+ gcc_cv_gas_minor_version=`expr "$gcc_cv_gas_version" : "VERSION=[0-9]*\.\([0-9]*\)"`
+ # Gas version 2.8 and later support specifying the maximum
+ # bytes to skip when using .p2align.
+ if [ "$gcc_cv_gas_major_version" -eq 2 -a "$gcc_cv_gas_minor_version" -ge 8 -o "$gcc_cv_gas_major_version" -gt 2 ]; then
+ gcc_cv_as_alignment_features=".p2align including maximum skip"
+ cat >> confdefs.h <<\EOF
+#define HAVE_GAS_MAX_SKIP_P2ALIGN 1
+EOF
+
+ fi
+elif [ x$host = x$target ]; then
+ # Native build.
+ gcc_cv_as=as$host_exeext
+fi
+if [ x$gcc_cv_as != x ]; then
+ # Check if specifying the maximum bytes to skip when
+ # using .p2align is supported.
+ echo ".p2align 4,,7" > conftest.s
+ if $gcc_cv_as -o conftest.o conftest.s > /dev/null 2>&1; then
+ gcc_cv_as_alignment_features=".p2align including maximum skip"
+ cat >> confdefs.h <<\EOF
+#define HAVE_GAS_MAX_SKIP_P2ALIGN 1
+EOF
+
+ fi
+ rm -f conftest.s conftest.o
+fi
+echo "$ac_t""$gcc_cv_as_alignment_features" 1>&6
+
# Figure out what language subdirectories are present.
subdirs=
for lang in ${srcdir}/*/config-lang.in ..
# fi
fi
+# Figure out what assembler alignment features are present.
+AC_MSG_CHECKING(assembler alignment features)
+gcc_cv_as=
+gcc_cv_as_alignment_features=
+if [[ -x as$host_exeext ]]; then
+ # Build using assembler in the current directory.
+ gcc_cv_as=./as$host_exeext
+elif [[ -f $srcdir/../gas/configure.in ]]; then
+ # Single tree build which includes gas.
+ for f in $srcdir/../gas/configure.in $srcdir/../gas/Makefile.in
+ do
+ gcc_cv_gas_version=`grep '^VERSION=[[0-9]]*\.[[0-9]]*' $f`
+ if [[ x$gcc_cv_gas_version != x ]]; then
+ break
+ fi
+ done
+ gcc_cv_gas_major_version=`expr "$gcc_cv_gas_version" : "VERSION=\([[0-9]]*\)"`
+ gcc_cv_gas_minor_version=`expr "$gcc_cv_gas_version" : "VERSION=[[0-9]]*\.\([[0-9]]*\)"`
+ # Gas version 2.8 and later support specifying the maximum
+ # bytes to skip when using .p2align.
+ if [[ "$gcc_cv_gas_major_version" -eq 2 -a "$gcc_cv_gas_minor_version" -ge 8 -o "$gcc_cv_gas_major_version" -gt 2 ]]; then
+ gcc_cv_as_alignment_features=".p2align including maximum skip"
+ AC_DEFINE(HAVE_GAS_MAX_SKIP_P2ALIGN)
+ fi
+elif [[ x$host = x$target ]]; then
+ # Native build.
+ gcc_cv_as=as$host_exeext
+fi
+if [[ x$gcc_cv_as != x ]]; then
+ # Check if specifying the maximum bytes to skip when
+ # using .p2align is supported.
+ echo ".p2align 4,,7" > conftest.s
+ if $gcc_cv_as -o conftest.o conftest.s > /dev/null 2>&1; then
+ gcc_cv_as_alignment_features=".p2align including maximum skip"
+ AC_DEFINE(HAVE_GAS_MAX_SKIP_P2ALIGN)
+ fi
+ rm -f conftest.s conftest.o
+fi
+AC_MSG_RESULT($gcc_cv_as_alignment_features)
+
# Figure out what language subdirectories are present.
subdirs=
for lang in ${srcdir}/*/config-lang.in ..
for each insn we'll call the alignment chain of this insn in the following
comments. */
-rtx *uid_align;
-int *uid_shuid;
-short *label_align;
+struct label_alignment {
+ short alignment;
+ short max_skip;
+};
+
+static rtx *uid_align;
+static int *uid_shuid;
+static struct label_alignment *label_align;
/* Indicate that branch shortening hasn't yet been done. */
#define LABEL_ALIGN(LABEL) 0
#endif
+#ifndef LABEL_ALIGN_MAX_SKIP
+#define LABEL_ALIGN_MAX_SKIP 0
+#endif
+
#ifndef LOOP_ALIGN
#define LOOP_ALIGN(LABEL) 0
#endif
+#ifndef LOOP_ALIGN_MAX_SKIP
+#define LOOP_ALIGN_MAX_SKIP 0
+#endif
+
#ifndef LABEL_ALIGN_AFTER_BARRIER
#define LABEL_ALIGN_AFTER_BARRIER(LABEL) 0
#endif
+#ifndef LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP
+#define LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP 0
+#endif
+
#ifndef ADDR_VEC_ALIGN
int
final_addr_vec_align (addr_vec)
static int min_labelno, max_labelno;
#define LABEL_TO_ALIGNMENT(LABEL) \
- (label_align[CODE_LABEL_NUMBER (LABEL) - min_labelno])
+ (label_align[CODE_LABEL_NUMBER (LABEL) - min_labelno].alignment)
+
+#define LABEL_TO_MAX_SKIP(LABEL) \
+ (label_align[CODE_LABEL_NUMBER (LABEL) - min_labelno].max_skip)
/* For the benefit of port specific code do this also as a function. */
int
int max_uid;
int i;
int max_log;
+ int max_skip;
#ifdef HAVE_ATTR_length
#define MAX_CODE_ALIGN 16
rtx seq;
max_labelno = max_label_num ();
min_labelno = get_first_label_num ();
- label_align
- = (short*) xmalloc ((max_labelno - min_labelno + 1) * sizeof (short));
- bzero ((char *) label_align,
- (max_labelno - min_labelno + 1) * sizeof (short));
+ label_align = (struct label_alignment *) xmalloc (
+ (max_labelno - min_labelno + 1) * sizeof (struct label_alignment));
+ bzero (label_align,
+ (max_labelno - min_labelno + 1) * sizeof (struct label_alignment));
uid_shuid = (int *) xmalloc (max_uid * sizeof *uid_shuid);
impose on the next CODE_LABEL (or the current one if we are processing
the CODE_LABEL itself). */
- for (max_log = 0, insn = get_insns (), i = 1; insn; insn = NEXT_INSN (insn))
+ max_log = 0;
+ max_skip = 0;
+
+ for (insn = get_insns (), i = 1; insn; insn = NEXT_INSN (insn))
{
int log;
log = LABEL_ALIGN (insn);
if (max_log < log)
- max_log = log;
+ {
+ max_log = log;
+ max_skip = LABEL_ALIGN_MAX_SKIP;
+ }
next = NEXT_INSN (insn);
/* ADDR_VECs only take room if read-only data goes into the text section. */
#if !defined(READONLY_DATA_SECTION) || defined(JUMP_TABLES_IN_TEXT_SECTION)
{
log = ADDR_VEC_ALIGN (next);
if (max_log < log)
- max_log = log;
+ {
+ max_log = log;
+ max_skip = LABEL_ALIGN_MAX_SKIP;
+ }
}
}
#endif
LABEL_TO_ALIGNMENT (insn) = max_log;
+ LABEL_TO_MAX_SKIP (insn) = max_skip;
max_log = 0;
+ max_skip = 0;
}
else if (GET_CODE (insn) == BARRIER)
{
{
log = LABEL_ALIGN_AFTER_BARRIER (insn);
if (max_log < log)
- max_log = log;
+ {
+ max_log = log;
+ max_skip = LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP;
+ }
break;
}
}
{
log = LOOP_ALIGN (insn);
if (max_log < log)
- max_log = log;
+ {
+ max_log = log;
+ max_skip = LOOP_ALIGN_MAX_SKIP;
+ }
break;
}
}
if (CODE_LABEL_NUMBER (insn) <= max_labelno)
{
int align = LABEL_TO_ALIGNMENT (insn);
+ int max_skip = LABEL_TO_MAX_SKIP (insn);
if (align && NEXT_INSN (insn))
+#ifdef ASM_OUTPUT_MAX_SKIP_ALIGN
+ ASM_OUTPUT_MAX_SKIP_ALIGN (file, align, max_skip);
+#else
ASM_OUTPUT_ALIGN (file, align);
+#endif
}
CC_STATUS_INIT;
if (prescan > 0)
@item -malign-loops=@var{num}
Align loops to a 2 raised to a @var{num} byte boundary. If
-@samp{-malign-loops} is not specified, the default is 2.
+@samp{-malign-loops} is not specified, the default is 2 unless
+gas 2.8 (or later) is being used in which case the default is
+to align the loop on a 16 byte boundary if it is less than 8
+bytes away.
@item -malign-jumps=@var{num}
Align instructions that are only jumped to to a 2 raised to a @var{num}
byte boundary. If @samp{-malign-jumps} is not specified, the default is
-2 if optimizing for a 386, and 4 if optimizing for a 486.
+2 if optimizing for a 386, and 4 if optimizing for a 486 unless
+gas 2.8 (or later) is being used in which case the default is
+to align the instruction on a 16 byte boundary if it is less
+than 8 bytes away.
@item -malign-functions=@var{num}
Align the start of functions to a 2 raised to @var{num} byte boundary.
git://gcc.gnu.org / gcc.git / commitdiff