diff options
| -rw-r--r-- | gcc/ChangeLog | 21 | ||||
| -rw-r--r-- | gcc/acconfig.h | 4 | ||||
| -rw-r--r-- | gcc/config.in | 4 | ||||
| -rw-r--r-- | gcc/config/i386/gas.h | 13 | ||||
| -rw-r--r-- | gcc/config/i386/i386.c | 8 | ||||
| -rw-r--r-- | gcc/config/i386/i386.h | 2 | ||||
| -rwxr-xr-x | gcc/configure | 47 | ||||
| -rw-r--r-- | gcc/configure.in | 40 | ||||
| -rw-r--r-- | gcc/final.c | 69 | ||||
| -rw-r--r-- | gcc/invoke.texi | 10 |
10 files changed, 203 insertions, 15 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index dd1456a..ba56e08 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,24 @@ +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. diff --git a/gcc/acconfig.h b/gcc/acconfig.h index 914fd43..904b7e44 100644 --- a/gcc/acconfig.h +++ b/gcc/acconfig.h @@ -10,6 +10,10 @@ /* 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 diff --git a/gcc/config.in b/gcc/config.in index 9283e71..38cc36d 100644 --- a/gcc/config.in +++ b/gcc/config.in @@ -11,6 +11,10 @@ /* 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 diff --git a/gcc/config/i386/gas.h b/gcc/config/i386/gas.h index 50976cf..2da338a 100644 --- a/gcc/config/i386/gas.h +++ b/gcc/config/i386/gas.h @@ -85,6 +85,19 @@ Boston, MA 02111-1307, USA. */ #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 /* A C statement or statements which output an assembler instruction opcode to the stdio stream STREAM. The macro-operand PTR is a diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 0e332a5..da08da1 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -332,7 +332,11 @@ override_options () 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) @@ -343,7 +347,11 @@ override_options () 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) diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h index b55ffcc..759e5c1 100644 --- a/gcc/config/i386/i386.h +++ b/gcc/config/i386/i386.h @@ -506,11 +506,13 @@ extern int ix86_arch; /* 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) /* Standard register usage. */ diff --git a/gcc/configure b/gcc/configure index e6eb22f..2375741 100755 --- a/gcc/configure +++ b/gcc/configure @@ -5070,6 +5070,53 @@ if [ -f ../ld/Makefile ]; then # 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 ${srcdir}/*/config-lang.in .. diff --git a/gcc/configure.in b/gcc/configure.in index 5728efc..bb6b46c 100644 --- a/gcc/configure.in +++ b/gcc/configure.in @@ -3226,6 +3226,46 @@ if [[ -f ../ld/Makefile ]]; then # fi fi +# Figure out what assembler alignment features are present. +AC_MSG_CHECKING(assembler alignment features) +gcc_cv_as= +gcc_cv_as_alignment_features= +if [[ -x as$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 .. diff --git a/gcc/final.c b/gcc/final.c index 9dac137..f6f6670 100644 --- a/gcc/final.c +++ b/gcc/final.c @@ -649,9 +649,14 @@ int insn_current_align; 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. */ @@ -794,14 +799,26 @@ get_attr_length (insn) #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) @@ -826,7 +843,10 @@ 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 @@ -962,6 +982,7 @@ shorten_branches (first) int max_uid; int i; int max_log; + int max_skip; #ifdef HAVE_ATTR_length #define MAX_CODE_ALIGN 16 rtx seq; @@ -1001,10 +1022,10 @@ shorten_branches (first) 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); @@ -1014,7 +1035,10 @@ shorten_branches (first) 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; @@ -1033,7 +1057,10 @@ shorten_branches (first) 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) @@ -1045,12 +1072,17 @@ shorten_branches (first) { 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) { @@ -1062,7 +1094,10 @@ shorten_branches (first) { 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; } } @@ -1078,7 +1113,10 @@ shorten_branches (first) { log = LOOP_ALIGN (insn); if (max_log < log) - max_log = log; + { + max_log = log; + max_skip = LOOP_ALIGN_MAX_SKIP; + } break; } } @@ -2222,9 +2260,14 @@ final_scan_insn (insn, file, optimize, prescan, nopeepholes) 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) diff --git a/gcc/invoke.texi b/gcc/invoke.texi index 2289f3c..4d1a413 100644 --- a/gcc/invoke.texi +++ b/gcc/invoke.texi @@ -4905,12 +4905,18 @@ startup modules. @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. |