crypto/perlasm/x86_64-xlate.pl

   1 #!/usr/bin/env perl
   2
   3 # Ascetic x86_64 AT&T to MASM/NASM assembler translator by <appro>.
   4 #
   5 # Why AT&T to MASM and not vice versa? Several reasons. Because AT&T
   6 # format is way easier to parse. Because it's simpler to "gear" from
   7 # Unix ABI to Windows one [see cross-reference "card" at the end of
   8 # file]. Because Linux targets were available first...
   9 #
  10 # In addition the script also "distills" code suitable for GNU
  11 # assembler, so that it can be compiled with more rigid assemblers,
  12 # such as Solaris /usr/ccs/bin/as.
  13 #
  14 # This translator is not designed to convert *arbitrary* assembler
  15 # code from AT&T format to MASM one. It's designed to convert just
  16 # enough to provide for dual-ABI OpenSSL modules development...
  17 # There *are* limitations and you might have to modify your assembler
  18 # code or this script to achieve the desired result...
  19 #
  20 # Currently recognized limitations:
  21 #
  22 # - can't use multiple ops per line;
  23 #
  24 # Dual-ABI styling rules.
  25 #
  26 # 1. Adhere to Unix register and stack layout [see cross-reference
  27 #    ABI "card" at the end for explanation].
  28 # 2. Forget about "red zone," stick to more traditional blended
  29 #    stack frame allocation. If volatile storage is actually required
  30 #    that is. If not, just leave the stack as is.
  31 # 3. Functions tagged with ".type name,@function" get crafted with
  32 #    unified Win64 prologue and epilogue automatically. If you want
  33 #    to take care of ABI differences yourself, tag functions as
  34 #    ".type name,@abi-omnipotent" instead.
  35 # 4. To optimize the Win64 prologue you can specify number of input
  36 #    arguments as ".type name,@function,N." Keep in mind that if N is
  37 #    larger than 6, then you *have to* write "abi-omnipotent" code,
  38 #    because >6 cases can't be addressed with unified prologue.
  39 # 5. Name local labels as .L*, do *not* use dynamic labels such as 1:
  40 #    (sorry about latter).
  41 # 6. Don't use [or hand-code with .byte] "rep ret." "ret" mnemonic is
  42 #    required to identify the spots, where to inject Win64 epilogue!
  43 #    But on the pros, it's then prefixed with rep automatically:-)
  44 # 7. Stick to explicit ip-relative addressing. If you have to use
  45 #    GOTPCREL addressing, stick to mov symbol@GOTPCREL(%rip),%r??.
  46 #    Both are recognized and translated to proper Win64 addressing
  47 #    modes. To support legacy code a synthetic directive, .picmeup,
  48 #    is implemented. It puts address of the *next* instruction into
  49 #    target register, e.g.:
  50 #
  51 #               .picmeup        %rax
  52 #               lea             .Label-.(%rax),%rax
  53 #
  54 # 8. In order to provide for structured exception handling unified
  55 #    Win64 prologue copies %rsp value to %rax. For further details
  56 #    see SEH paragraph at the end.
  57 # 9. .init segment is allowed to contain calls to functions only.
  58 # a. If function accepts more than 4 arguments *and* >4th argument
  59 #    is declared as non 64-bit value, do clear its upper part.
  60 \f
  61 my $flavour = shift;
  62 my $output  = shift;
  63 if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
  64
  65 open STDOUT,">$output" || die "can't open $output: $!"
  66         if (defined($output));
  67
  68 my $gas=1;      $gas=0 if ($output =~ /\.asm$/);
  69 my $elf=1;      $elf=0 if (!$gas);
  70 my $win64=0;
  71 my $prefix="";
  72 my $decor=".L";
  73
  74 my $masmref=8 + 50727*2**-32;   # 8.00.50727 shipped with VS2005
  75 my $masm=0;
  76 my $PTR=" PTR";
  77
  78 my $nasmref=2.03;
  79 my $nasm=0;
  80
  81 if    ($flavour eq "mingw64")   { $gas=1; $elf=0; $win64=1;
  82                                   $prefix=`echo __USER_LABEL_PREFIX__ | $ENV{CC} -E -P -`;
  83                                   chomp($prefix);
  84                                 }
  85 elsif ($flavour eq "macosx")    { $gas=1; $elf=0; $prefix="_"; $decor="L\$"; }
  86 elsif ($flavour eq "masm")      { $gas=0; $elf=0; $masm=$masmref; $win64=1; $decor="\$L\$"; }
  87 elsif ($flavour eq "nasm")      { $gas=0; $elf=0; $nasm=$nasmref; $win64=1; $decor="\$L\$"; $PTR=""; }
  88 elsif (!$gas)
  89 {   if ($ENV{ASM} =~ m/nasm/ && `nasm -v` =~ m/version ([0-9]+)\.([0-9]+)/i)
  90     {   $nasm = $1 + $2*0.01; $PTR="";  }
  91     elsif (`ml64 2>&1` =~ m/Version ([0-9]+)\.([0-9]+)(\.([0-9]+))?/)
  92     {   $masm = $1 + $2*2**-16 + $4*2**-32;   }
  93     die "no assembler found on %PATH" if (!($nasm || $masm));
  94     $win64=1;
  95     $elf=0;
  96     $decor="\$L\$";
  97 }
  98
  99 my $current_segment;
 100 my $current_function;
 101 my %globals;
 102
 103 { package opcode;       # pick up opcodes
 104     sub re {
 105         my      $self = shift;  # single instance in enough...
 106         local   *line = shift;
 107         undef   $ret;
 108
 109         if ($line =~ /^([a-z][a-z0-9]*)/i) {
 110             $self->{op} = $1;
 111             $ret = $self;
 112             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 113
 114             undef $self->{sz};
 115             if ($self->{op} =~ /^(movz)b.*/) {  # movz is pain...
 116                 $self->{op} = $1;
 117                 $self->{sz} = "b";
 118             } elsif ($self->{op} =~ /call|jmp/) {
 119                 $self->{sz} = "";
 120             } elsif ($self->{op} =~ /^p/ && $' !~ /^(ush|op)/) { # SSEn
 121                 $self->{sz} = "";
 122             } elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) {
 123                 $self->{op} = $1;
 124                 $self->{sz} = $2;
 125             }
 126         }
 127         $ret;
 128     }
 129     sub size {
 130         my $self = shift;
 131         my $sz   = shift;
 132         $self->{sz} = $sz if (defined($sz) && !defined($self->{sz}));
 133         $self->{sz};
 134     }
 135     sub out {
 136         my $self = shift;
 137         if ($gas) {
 138             if ($self->{op} eq "movz") {        # movz is pain...
 139                 sprintf "%s%s%s",$self->{op},$self->{sz},shift;
 140             } elsif ($self->{op} =~ /^set/) {
 141                 "$self->{op}";
 142             } elsif ($self->{op} eq "ret") {
 143                 my $epilogue = "";
 144                 if ($win64 && $current_function->{abi} eq "svr4") {
 145                     $epilogue = "movq   8(%rsp),%rdi\n\t" .
 146                                 "movq   16(%rsp),%rsi\n\t";
 147                 }
 148                 $epilogue . ".byte      0xf3,0xc3";
 149             } elsif ($self->{op} eq "call" && !$elf && $current_segment eq ".init") {
 150                 ".p2align\t3\n\t.quad";
 151             } else {
 152                 "$self->{op}$self->{sz}";
 153             }
 154         } else {
 155             $self->{op} =~ s/^movz/movzx/;
 156             if ($self->{op} eq "ret") {
 157                 $self->{op} = "";
 158                 if ($win64 && $current_function->{abi} eq "svr4") {
 159                     $self->{op} = "mov  rdi,QWORD${PTR}[8+rsp]\t;WIN64 epilogue\n\t".
 160                                   "mov  rsi,QWORD${PTR}[16+rsp]\n\t";
 161                 }
 162                 $self->{op} .= "DB\t0F3h,0C3h\t\t;repret";
 163             } elsif ($self->{op} =~ /^(pop|push)f/) {
 164                 $self->{op} .= $self->{sz};
 165             } elsif ($self->{op} eq "call" && $current_segment eq ".CRT\$XCU") {
 166                 $self->{op} = "\tDQ";
 167             }
 168             $self->{op};
 169         }
 170     }
 171     sub mnemonic {
 172         my $self=shift;
 173         my $op=shift;
 174         $self->{op}=$op if (defined($op));
 175         $self->{op};
 176     }
 177 }
 178 { package const;        # pick up constants, which start with $
 179     sub re {
 180         my      $self = shift;  # single instance in enough...
 181         local   *line = shift;
 182         undef   $ret;
 183
 184         if ($line =~ /^\$([^,]+)/) {
 185             $self->{value} = $1;
 186             $ret = $self;
 187             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 188         }
 189         $ret;
 190     }
 191     sub out {
 192         my $self = shift;
 193
 194         if ($gas) {
 195             # Solaris /usr/ccs/bin/as can't handle multiplications
 196             # in $self->{value}
 197             $self->{value} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi;
 198             $self->{value} =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg;
 199             sprintf "\$%s",$self->{value};
 200         } else {
 201             $self->{value} =~ s/(0b[0-1]+)/oct($1)/eig;
 202             $self->{value} =~ s/0x([0-9a-f]+)/0$1h/ig if ($masm);
 203             sprintf "%s",$self->{value};
 204         }
 205     }
 206 }
 207 { package ea;           # pick up effective addresses: expr(%reg,%reg,scale)
 208     sub re {
 209         my      $self = shift;  # single instance in enough...
 210         local   *line = shift;
 211         undef   $ret;
 212
 213         # optional * ---vvv--- appears in indirect jmp/call
 214         if ($line =~ /^(\*?)([^\(,]*)\(([%\w,]+)\)/) {
 215             $self->{asterisk} = $1;
 216             $self->{label} = $2;
 217             ($self->{base},$self->{index},$self->{scale})=split(/,/,$3);
 218             $self->{scale} = 1 if (!defined($self->{scale}));
 219             $ret = $self;
 220             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 221
 222             if ($win64 && $self->{label} =~ s/\@GOTPCREL//) {
 223                 die if (opcode->mnemonic() ne "mov");
 224                 opcode->mnemonic("lea");
 225             }
 226             $self->{base}  =~ s/^%//;
 227             $self->{index} =~ s/^%// if (defined($self->{index}));
 228         }
 229         $ret;
 230     }
 231     sub size {}
 232     sub out {
 233         my $self = shift;
 234         my $sz = shift;
 235
 236         $self->{label} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;
 237         $self->{label} =~ s/\.L/$decor/g;
 238
 239         # Silently convert all EAs to 64-bit. This is required for
 240         # elder GNU assembler and results in more compact code,
 241         # *but* most importantly AES module depends on this feature!
 242         $self->{index} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/;
 243         $self->{base}  =~ s/^[er](.?[0-9xpi])[d]?$/r\1/;
 244
 245         if ($gas) {
 246             # Solaris /usr/ccs/bin/as can't handle multiplications
 247             # in $self->{label}, new gas requires sign extension...
 248             use integer;
 249             $self->{label} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi;
 250             $self->{label} =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg;
 251             $self->{label} =~ s/([0-9]+)/$1<<32>>32/eg;
 252             $self->{label} =~ s/^___imp_/__imp__/   if ($flavour eq "mingw64");
 253
 254             if (defined($self->{index})) {
 255                 sprintf "%s%s(%%%s,%%%s,%d)",$self->{asterisk},
 256                                         $self->{label},$self->{base},
 257                                         $self->{index},$self->{scale};
 258             } else {
 259                 sprintf "%s%s(%%%s)",   $self->{asterisk},$self->{label},$self->{base};
 260             }
 261         } else {
 262             %szmap = ( b=>"BYTE$PTR", w=>"WORD$PTR", l=>"DWORD$PTR", q=>"QWORD$PTR" );
 263
 264             $self->{label} =~ s/\./\$/g;
 265             $self->{label} =~ s/(?<![\w\$\.])0x([0-9a-f]+)/0$1h/ig;
 266             $self->{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/);
 267             $sz="q" if ($self->{asterisk});
 268
 269             if (defined($self->{index})) {
 270                 sprintf "%s[%s%s*%d+%s]",$szmap{$sz},
 271                                         $self->{label}?"$self->{label}+":"",
 272                                         $self->{index},$self->{scale},
 273                                         $self->{base};
 274             } elsif ($self->{base} eq "rip") {
 275                 sprintf "%s[%s]",$szmap{$sz},$self->{label};
 276             } else {
 277                 sprintf "%s[%s%s]",$szmap{$sz},
 278                                         $self->{label}?"$self->{label}+":"",
 279                                         $self->{base};
 280             }
 281         }
 282     }
 283 }
 284 { package register;     # pick up registers, which start with %.
 285     sub re {
 286         my      $class = shift; # muliple instances...
 287         my      $self = {};
 288         local   *line = shift;
 289         undef   $ret;
 290
 291         # optional * ---vvv--- appears in indirect jmp/call
 292         if ($line =~ /^(\*?)%(\w+)/) {
 293             bless $self,$class;
 294             $self->{asterisk} = $1;
 295             $self->{value} = $2;
 296             $ret = $self;
 297             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 298         }
 299         $ret;
 300     }
 301     sub size {
 302         my      $self = shift;
 303         undef   $ret;
 304
 305         if    ($self->{value} =~ /^r[\d]+b$/i)  { $ret="b"; }
 306         elsif ($self->{value} =~ /^r[\d]+w$/i)  { $ret="w"; }
 307         elsif ($self->{value} =~ /^r[\d]+d$/i)  { $ret="l"; }
 308         elsif ($self->{value} =~ /^r[\w]+$/i)   { $ret="q"; }
 309         elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; }
 310         elsif ($self->{value} =~ /^[\w]{2}l$/i) { $ret="b"; }
 311         elsif ($self->{value} =~ /^[\w]{2}$/i)  { $ret="w"; }
 312         elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; }
 313
 314         $ret;
 315     }
 316     sub out {
 317         my $self = shift;
 318         if ($gas)       { sprintf "%s%%%s",$self->{asterisk},$self->{value}; }
 319         else            { $self->{value}; }
 320     }
 321 }
 322 { package label;        # pick up labels, which end with :
 323     sub re {
 324         my      $self = shift;  # single instance is enough...
 325         local   *line = shift;
 326         undef   $ret;
 327
 328         if ($line =~ /(^[\.\w]+)\:/) {
 329             $self->{value} = $1;
 330             $ret = $self;
 331             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 332
 333             $self->{value} =~ s/^\.L/$decor/;
 334         }
 335         $ret;
 336     }
 337     sub out {
 338         my $self = shift;
 339
 340         if ($gas) {
 341             my $func = ($globals{$self->{value}} or $self->{value}) . ":";
 342             if ($win64  &&
 343                         $current_function->{name} eq $self->{value} &&
 344                         $current_function->{abi} eq "svr4") {
 345                 $func .= "\n";
 346                 $func .= "      movq    %rdi,8(%rsp)\n";
 347                 $func .= "      movq    %rsi,16(%rsp)\n";
 348                 $func .= "      movq    %rsp,%rax\n";
 349                 $func .= "${decor}SEH_begin_$current_function->{name}:\n";
 350                 my $narg = $current_function->{narg};
 351                 $narg=6 if (!defined($narg));
 352                 $func .= "      movq    %rcx,%rdi\n" if ($narg>0);
 353                 $func .= "      movq    %rdx,%rsi\n" if ($narg>1);
 354                 $func .= "      movq    %r8,%rdx\n"  if ($narg>2);
 355                 $func .= "      movq    %r9,%rcx\n"  if ($narg>3);
 356                 $func .= "      movq    40(%rsp),%r8\n" if ($narg>4);
 357                 $func .= "      movq    48(%rsp),%r9\n" if ($narg>5);
 358             }
 359             $func;
 360         } elsif ($self->{value} ne "$current_function->{name}") {
 361             $self->{value} .= ":" if ($masm && $ret!~m/^\$/);
 362             $self->{value} . ":";
 363         } elsif ($win64 && $current_function->{abi} eq "svr4") {
 364             my $func =  "$current_function->{name}" .
 365                         ($nasm ? ":" : "\tPROC $current_function->{scope}") .
 366                         "\n";
 367             $func .= "  mov     QWORD${PTR}[8+rsp],rdi\t;WIN64 prologue\n";
 368             $func .= "  mov     QWORD${PTR}[16+rsp],rsi\n";
 369             $func .= "  mov     rax,rsp\n";
 370             $func .= "${decor}SEH_begin_$current_function->{name}:";
 371             $func .= ":" if ($masm);
 372             $func .= "\n";
 373             my $narg = $current_function->{narg};
 374             $narg=6 if (!defined($narg));
 375             $func .= "  mov     rdi,rcx\n" if ($narg>0);
 376             $func .= "  mov     rsi,rdx\n" if ($narg>1);
 377             $func .= "  mov     rdx,r8\n"  if ($narg>2);
 378             $func .= "  mov     rcx,r9\n"  if ($narg>3);
 379             $func .= "  mov     r8,QWORD${PTR}[40+rsp]\n" if ($narg>4);
 380             $func .= "  mov     r9,QWORD${PTR}[48+rsp]\n" if ($narg>5);
 381             $func .= "\n";
 382         } else {
 383            "$current_function->{name}".
 384                         ($nasm ? ":" : "\tPROC $current_function->{scope}");
 385         }
 386     }
 387 }
 388 { package expr;         # pick up expressioins
 389     sub re {
 390         my      $self = shift;  # single instance is enough...
 391         local   *line = shift;
 392         undef   $ret;
 393
 394         if ($line =~ /(^[^,]+)/) {
 395             $self->{value} = $1;
 396             $ret = $self;
 397             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 398
 399             $self->{value} =~ s/\@PLT// if (!$elf);
 400             $self->{value} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;
 401             $self->{value} =~ s/\.L/$decor/g;
 402         }
 403         $ret;
 404     }
 405     sub out {
 406         my $self = shift;
 407         if ($nasm && opcode->mnemonic()=~m/^j/) {
 408             "NEAR ".$self->{value};
 409         } else {
 410             $self->{value};
 411         }
 412     }
 413 }
 414 { package directive;    # pick up directives, which start with .
 415     sub re {
 416         my      $self = shift;  # single instance is enough...
 417         local   *line = shift;
 418         undef   $ret;
 419         my      $dir;
 420         my      %opcode =       # lea 2f-1f(%rip),%dst; 1: nop; 2:
 421                 (       "%rax"=>0x01058d48,     "%rcx"=>0x010d8d48,
 422                         "%rdx"=>0x01158d48,     "%rbx"=>0x011d8d48,
 423                         "%rsp"=>0x01258d48,     "%rbp"=>0x012d8d48,
 424                         "%rsi"=>0x01358d48,     "%rdi"=>0x013d8d48,
 425                         "%r8" =>0x01058d4c,     "%r9" =>0x010d8d4c,
 426                         "%r10"=>0x01158d4c,     "%r11"=>0x011d8d4c,
 427                         "%r12"=>0x01258d4c,     "%r13"=>0x012d8d4c,
 428                         "%r14"=>0x01358d4c,     "%r15"=>0x013d8d4c      );
 429
 430         if ($line =~ /^\s*(\.\w+)/) {
 431             $dir = $1;
 432             $ret = $self;
 433             undef $self->{value};
 434             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 435
 436             SWITCH: for ($dir) {
 437                 /\.picmeup/ && do { if ($line =~ /(%r[\w]+)/i) {
 438                                         $dir="\t.long";
 439                                         $line=sprintf "0x%x,0x90000000",$opcode{$1};
 440                                     }
 441                                     last;
 442                                   };
 443                 /\.global|\.globl|\.extern/
 444                             && do { $globals{$line} = $prefix . $line;
 445                                     $line = $globals{$line} if ($prefix);
 446                                     last;
 447                                   };
 448                 /\.type/    && do { ($sym,$type,$narg) = split(',',$line);
 449                                     if ($type eq "\@function") {
 450                                         undef $current_function;
 451                                         $current_function->{name} = $sym;
 452                                         $current_function->{abi}  = "svr4";
 453                                         $current_function->{narg} = $narg;
 454                                         $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE";
 455                                     } elsif ($type eq "\@abi-omnipotent") {
 456                                         undef $current_function;
 457                                         $current_function->{name} = $sym;
 458                                         $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE";
 459                                     }
 460                                     $line =~ s/\@abi\-omnipotent/\@function/;
 461                                     $line =~ s/\@function.*/\@function/;
 462                                     last;
 463                                   };
 464                 /\.asciz/   && do { if ($line =~ /^"(.*)"$/) {
 465                                         $dir  = ".byte";
 466                                         $line = join(",",unpack("C*",$1),0);
 467                                     }
 468                                     last;
 469                                   };
 470                 /\.rva|\.long|\.quad/
 471                             && do { $line =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;
 472                                     $line =~ s/\.L/$decor/g;
 473                                     last;
 474                                   };
 475             }
 476
 477             if ($gas) {
 478                 $self->{value} = $dir . "\t" . $line;
 479
 480                 if ($dir =~ /\.extern/) {
 481                     $self->{value} = ""; # swallow extern
 482                 } elsif (!$elf && $dir =~ /\.type/) {
 483                     $self->{value} = "";
 484                     $self->{value} = ".def\t" . ($globals{$1} or $1) . ";\t" .
 485                                 (defined($globals{$1})?".scl 2;":".scl 3;") .
 486                                 "\t.type 32;\t.endef"
 487                                 if ($win64 && $line =~ /([^,]+),\@function/);
 488                 } elsif (!$elf && $dir =~ /\.size/) {
 489                     $self->{value} = "";
 490                     if (defined($current_function)) {
 491                         $self->{value} .= "${decor}SEH_end_$current_function->{name}:"
 492                                 if ($win64 && $current_function->{abi} eq "svr4");
 493                         undef $current_function;
 494                     }
 495                 } elsif (!$elf && $dir =~ /\.align/) {
 496                     $self->{value} = ".p2align\t" . (log($line)/log(2));
 497                 } elsif ($dir eq ".section") {
 498                     $current_segment=$line;
 499                     if (!$elf && $current_segment eq ".init") {
 500                         if      ($flavour eq "macosx")  { $self->{value} = ".mod_init_func"; }
 501                         elsif   ($flavour eq "mingw64") { $self->{value} = ".section\t.ctors"; }
 502                     }
 503                 } elsif ($dir =~ /\.(text|data)/) {
 504                     $current_segment=".$1";
 505                 }
 506                 $line = "";
 507                 return $self;
 508             }
 509
 510             # non-gas case or nasm/masm
 511             SWITCH: for ($dir) {
 512                 /\.text/    && do { my $v=undef;
 513                                     if ($nasm) {
 514                                         $v="section     .text code align=64\n";
 515                                     } else {
 516                                         $v="$current_segment\tENDS\n" if ($current_segment);
 517                                         $current_segment = ".text\$";
 518                                         $v.="$current_segment\tSEGMENT ";
 519                                         $v.=$masm>=$masmref ? "ALIGN(64)" : "PAGE";
 520                                         $v.=" 'CODE'";
 521                                     }
 522                                     $self->{value} = $v;
 523                                     last;
 524                                   };
 525                 /\.data/    && do { my $v=undef;
 526                                     if ($nasm) {
 527                                         $v="section     .data data align=8\n";
 528                                     } else {
 529                                         $v="$current_segment\tENDS\n" if ($current_segment);
 530                                         $current_segment = "_DATA";
 531                                         $v.="$current_segment\tSEGMENT";
 532                                     }
 533                                     $self->{value} = $v;
 534                                     last;
 535                                   };
 536                 /\.section/ && do { my $v=undef;
 537                                     $line =~ s/([^,]*).*/$1/;
 538                                     $line = ".CRT\$XCU" if ($line eq ".init");
 539                                     if ($nasm) {
 540                                         $v="section     $line";
 541                                         if ($line=~/\.([px])data/) {
 542                                             $v.=" rdata align=";
 543                                             $v.=$1 eq "p"? 4 : 8;
 544                                         } elsif ($line=~/\.CRT\$/i) {
 545                                             $v.=" rdata align=8";
 546                                         }
 547                                     } else {
 548                                         $v="$current_segment\tENDS\n" if ($current_segment);
 549                                         $v.="$line\tSEGMENT";
 550                                         if ($line=~/\.([px])data/) {
 551                                             $v.=" READONLY";
 552                                             $v.=" ALIGN(".($1 eq "p" ? 4 : 8).")" if ($masm>=$masmref);
 553                                         } elsif ($line=~/\.CRT\$/i) {
 554                                             $v.=" READONLY ";
 555                                             $v.=$masm>=$masmref ? "ALIGN(8)" : "DWORD";
 556                                         }
 557                                     }
 558                                     $current_segment = $line;
 559                                     $self->{value} = $v;
 560                                     last;
 561                                   };
 562                 /\.extern/  && do { $self->{value}  = "EXTERN\t".$line;
 563                                     $self->{value} .= ":NEAR" if ($masm);
 564                                     last;
 565                                   };
 566                 /\.globl|.global/
 567                             && do { $self->{value}  = $masm?"PUBLIC":"global";
 568                                     $self->{value} .= "\t".$line;
 569                                     last;
 570                                   };
 571                 /\.size/    && do { if (defined($current_function)) {
 572                                         undef $self->{value};
 573                                         if ($current_function->{abi} eq "svr4") {
 574                                             $self->{value}="${decor}SEH_end_$current_function->{name}:";
 575                                             $self->{value}.=":\n" if($masm);
 576                                         }
 577                                         $self->{value}.="$current_function->{name}\tENDP" if($masm);
 578                                         undef $current_function;
 579                                     }
 580                                     last;
 581                                   };
 582                 /\.align/   && do { $self->{value} = "ALIGN\t".$line; last; };
 583                 /\.(value|long|rva|quad)/
 584                             && do { my $sz  = substr($1,0,1);
 585                                     my @arr = split(/,\s*/,$line);
 586                                     my $last = pop(@arr);
 587                                     my $conv = sub  {   my $var=shift;
 588                                                         $var=~s/^(0b[0-1]+)/oct($1)/eig;
 589                                                         $var=~s/^0x([0-9a-f]+)/0$1h/ig if ($masm);
 590                                                         if ($sz eq "D" && ($current_segment=~/.[px]data/ || $dir eq ".rva"))
 591                                                         { $var=~s/([_a-z\$\@][_a-z0-9\$\@]*)/$nasm?"$1 wrt ..imagebase":"imagerel $1"/egi; }
 592                                                         $var;
 593                                                     };
 594
 595                                     $sz =~ tr/bvlrq/BWDDQ/;
 596                                     $self->{value} = "\tD$sz\t";
 597                                     for (@arr) { $self->{value} .= &$conv($_).","; }
 598                                     $self->{value} .= &$conv($last);
 599                                     last;
 600                                   };
 601                 /\.byte/    && do { my @str=split(/,\s*/,$line);
 602                                     map(s/(0b[0-1]+)/oct($1)/eig,@str);
 603                                     map(s/0x([0-9a-f]+)/0$1h/ig,@str) if ($masm);
 604                                     while ($#str>15) {
 605                                         $self->{value}.="DB\t"
 606                                                 .join(",",@str[0..15])."\n";
 607                                         foreach (0..15) { shift @str; }
 608                                     }
 609                                     $self->{value}.="DB\t"
 610                                                 .join(",",@str) if (@str);
 611                                     last;
 612                                   };
 613             }
 614             $line = "";
 615         }
 616
 617         $ret;
 618     }
 619     sub out {
 620         my $self = shift;
 621         $self->{value};
 622     }
 623 }
 624
 625 if ($nasm) {
 626     print <<___;
 627 default rel
 628 ___
 629 } elsif ($masm) {
 630     print <<___;
 631 OPTION  DOTNAME
 632 ___
 633 }
 634 while($line=<>) {
 635
 636     chomp($line);
 637
 638     $line =~ s|[#!].*$||;       # get rid of asm-style comments...
 639     $line =~ s|/\*.*\*/||;      # ... and C-style comments...
 640     $line =~ s|^\s+||;          # ... and skip white spaces in beginning
 641
 642     undef $label;
 643     undef $opcode;
 644     undef $sz;
 645     undef @args;
 646
 647     if ($label=label->re(\$line))       { print $label->out(); }
 648
 649     if (directive->re(\$line)) {
 650         printf "%s",directive->out();
 651     } elsif ($opcode=opcode->re(\$line)) { ARGUMENT: while (1) {
 652         my $arg;
 653
 654         if ($arg=register->re(\$line))  { opcode->size($arg->size()); }
 655         elsif ($arg=const->re(\$line))  { }
 656         elsif ($arg=ea->re(\$line))     { }
 657         elsif ($arg=expr->re(\$line))   { }
 658         else                            { last ARGUMENT; }
 659
 660         push @args,$arg;
 661
 662         last ARGUMENT if ($line !~ /^,/);
 663
 664         $line =~ s/^,\s*//;
 665         } # ARGUMENT:
 666
 667         $sz=opcode->size();
 668
 669         if ($#args>=0) {
 670             my $insn;
 671             if ($gas) {
 672                 $insn = $opcode->out($#args>=1?$args[$#args]->size():$sz);
 673             } else {
 674                 $insn = $opcode->out();
 675                 $insn .= $sz if (map($_->out() =~ /x?mm/,@args));
 676                 @args = reverse(@args);
 677                 undef $sz if ($nasm && $opcode->mnemonic() eq "lea");
 678             }
 679             printf "\t%s\t%s",$insn,join(",",map($_->out($sz),@args));
 680         } else {
 681             printf "\t%s",$opcode->out();
 682         }
 683     }
 684
 685     print $line,"\n";
 686 }
 687
 688 print "\n$current_segment\tENDS\n"      if ($current_segment && $masm);
 689 print "END\n"                           if ($masm);
 690
 691 close STDOUT;
 692
 693 \f#################################################
 694 # Cross-reference x86_64 ABI "card"
 695 #
 696 #               Unix            Win64
 697 # %rax          *               *
 698 # %rbx          -               -
 699 # %rcx          #4              #1
 700 # %rdx          #3              #2
 701 # %rsi          #2              -
 702 # %rdi          #1              -
 703 # %rbp          -               -
 704 # %rsp          -               -
 705 # %r8           #5              #3
 706 # %r9           #6              #4
 707 # %r10          *               *
 708 # %r11          *               *
 709 # %r12          -               -
 710 # %r13          -               -
 711 # %r14          -               -
 712 # %r15          -               -
 713 #
 714 # (*)   volatile register
 715 # (-)   preserved by callee
 716 # (#)   Nth argument, volatile
 717 #
 718 # In Unix terms top of stack is argument transfer area for arguments
 719 # which could not be accomodated in registers. Or in other words 7th
 720 # [integer] argument resides at 8(%rsp) upon function entry point.
 721 # 128 bytes above %rsp constitute a "red zone" which is not touched
 722 # by signal handlers and can be used as temporal storage without
 723 # allocating a frame.
 724 #
 725 # In Win64 terms N*8 bytes on top of stack is argument transfer area,
 726 # which belongs to/can be overwritten by callee. N is the number of
 727 # arguments passed to callee, *but* not less than 4! This means that
 728 # upon function entry point 5th argument resides at 40(%rsp), as well
 729 # as that 32 bytes from 8(%rsp) can always be used as temporal
 730 # storage [without allocating a frame]. One can actually argue that
 731 # one can assume a "red zone" above stack pointer under Win64 as well.
 732 # Point is that at apparently no occasion Windows kernel would alter
 733 # the area above user stack pointer in true asynchronous manner...
 734 #
 735 # All the above means that if assembler programmer adheres to Unix
 736 # register and stack layout, but disregards the "red zone" existense,
 737 # it's possible to use following prologue and epilogue to "gear" from
 738 # Unix to Win64 ABI in leaf functions with not more than 6 arguments.
 739 #
 740 # omnipotent_function:
 741 # ifdef WIN64
 742 #       movq    %rdi,8(%rsp)
 743 #       movq    %rsi,16(%rsp)
 744 #       movq    %rcx,%rdi       ; if 1st argument is actually present
 745 #       movq    %rdx,%rsi       ; if 2nd argument is actually ...
 746 #       movq    %r8,%rdx        ; if 3rd argument is ...
 747 #       movq    %r9,%rcx        ; if 4th argument ...
 748 #       movq    40(%rsp),%r8    ; if 5th ...
 749 #       movq    48(%rsp),%r9    ; if 6th ...
 750 # endif
 751 #       ...
 752 # ifdef WIN64
 753 #       movq    8(%rsp),%rdi
 754 #       movq    16(%rsp),%rsi
 755 # endif
 756 #       ret
 757 #
 758 \f#################################################
 759 # Win64 SEH, Structured Exception Handling.
 760 #
 761 # Unlike on Unix systems(*) lack of Win64 stack unwinding information
 762 # has undesired side-effect at run-time: if an exception is raised in
 763 # assembler subroutine such as those in question (basically we're
 764 # referring to segmentation violations caused by malformed input
 765 # parameters), the application is briskly terminated without invoking
 766 # any exception handlers, most notably without generating memory dump
 767 # or any user notification whatsoever. This poses a problem. It's
 768 # possible to address it by registering custom language-specific
 769 # handler that would restore processor context to the state at
 770 # subroutine entry point and return "exception is not handled, keep
 771 # unwinding" code. Writing such handler can be a challenge... But it's
 772 # doable, though requires certain coding convention. Consider following
 773 # snippet:
 774 #
 775 # .type function,@function
 776 # function:
 777 #       movq    %rsp,%rax       # copy rsp to volatile register
 778 #       pushq   %r15            # save non-volatile registers
 779 #       pushq   %rbx
 780 #       pushq   %rbp
 781 #       movq    %rsp,%r11
 782 #       subq    %rdi,%r11       # prepare [variable] stack frame
 783 #       andq    $-64,%r11
 784 #       movq    %rax,0(%r11)    # check for exceptions
 785 #       movq    %r11,%rsp       # allocate [variable] stack frame
 786 #       movq    %rax,0(%rsp)    # save original rsp value
 787 # magic_point:
 788 #       ...
 789 #       movq    0(%rsp),%rcx    # pull original rsp value
 790 #       movq    -24(%rcx),%rbp  # restore non-volatile registers
 791 #       movq    -16(%rcx),%rbx
 792 #       movq    -8(%rcx),%r15
 793 #       movq    %rcx,%rsp       # restore original rsp
 794 #       ret
 795 # .size function,.-function
 796 #
 797 # The key is that up to magic_point copy of original rsp value remains
 798 # in chosen volatile register and no non-volatile register, except for
 799 # rsp, is modified. While past magic_point rsp remains constant till
 800 # the very end of the function. In this case custom language-specific
 801 # exception handler would look like this:
 802 #
 803 # EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame,
 804 #               CONTEXT *context,DISPATCHER_CONTEXT *disp)
 805 # {     ULONG64 *rsp = (ULONG64 *)context->Rax;
 806 #       if (context->Rip >= magic_point)
 807 #       {   rsp = ((ULONG64 **)context->Rsp)[0];
 808 #           context->Rbp = rsp[-3];
 809 #           context->Rbx = rsp[-2];
 810 #           context->R15 = rsp[-1];
 811 #       }
 812 #       context->Rsp = (ULONG64)rsp;
 813 #       context->Rdi = rsp[1];
 814 #       context->Rsi = rsp[2];
 815 #
 816 #       memcpy (disp->ContextRecord,context,sizeof(CONTEXT));
 817 #       RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase,
 818 #               dips->ControlPc,disp->FunctionEntry,disp->ContextRecord,
 819 #               &disp->HandlerData,&disp->EstablisherFrame,NULL);
 820 #       return ExceptionContinueSearch;
 821 # }
 822 #
 823 # It's appropriate to implement this handler in assembler, directly in
 824 # function's module. In order to do that one has to know members'
 825 # offsets in CONTEXT and DISPATCHER_CONTEXT structures and some constant
 826 # values. Here they are:
 827 #
 828 #       CONTEXT.Rax                             120
 829 #       CONTEXT.Rcx                             128
 830 #       CONTEXT.Rdx                             136
 831 #       CONTEXT.Rbx                             144
 832 #       CONTEXT.Rsp                             152
 833 #       CONTEXT.Rbp                             160
 834 #       CONTEXT.Rsi                             168
 835 #       CONTEXT.Rdi                             176
 836 #       CONTEXT.R8                              184
 837 #       CONTEXT.R9                              192
 838 #       CONTEXT.R10                             200
 839 #       CONTEXT.R11                             208
 840 #       CONTEXT.R12                             216
 841 #       CONTEXT.R13                             224
 842 #       CONTEXT.R14                             232
 843 #       CONTEXT.R15                             240
 844 #       CONTEXT.Rip                             248
 845 #       CONTEXT.Xmm6                            512
 846 #       sizeof(CONTEXT)                         1232
 847 #       DISPATCHER_CONTEXT.ControlPc            0
 848 #       DISPATCHER_CONTEXT.ImageBase            8
 849 #       DISPATCHER_CONTEXT.FunctionEntry        16
 850 #       DISPATCHER_CONTEXT.EstablisherFrame     24
 851 #       DISPATCHER_CONTEXT.TargetIp             32
 852 #       DISPATCHER_CONTEXT.ContextRecord        40
 853 #       DISPATCHER_CONTEXT.LanguageHandler      48
 854 #       DISPATCHER_CONTEXT.HandlerData          56
 855 #       UNW_FLAG_NHANDLER                       0
 856 #       ExceptionContinueSearch                 1
 857 #
 858 # In order to tie the handler to the function one has to compose
 859 # couple of structures: one for .xdata segment and one for .pdata.
 860 #
 861 # UNWIND_INFO structure for .xdata segment would be
 862 #
 863 # function_unwind_info:
 864 #       .byte   9,0,0,0
 865 #       .rva    handler
 866 #
 867 # This structure designates exception handler for a function with
 868 # zero-length prologue, no stack frame or frame register.
 869 #
 870 # To facilitate composing of .pdata structures, auto-generated "gear"
 871 # prologue copies rsp value to rax and denotes next instruction with
 872 # .LSEH_begin_{function_name} label. This essentially defines the SEH
 873 # styling rule mentioned in the beginning. Position of this label is
 874 # chosen in such manner that possible exceptions raised in the "gear"
 875 # prologue would be accounted to caller and unwound from latter's frame.
 876 # End of function is marked with respective .LSEH_end_{function_name}
 877 # label. To summarize, .pdata segment would contain
 878 #
 879 #       .rva    .LSEH_begin_function
 880 #       .rva    .LSEH_end_function
 881 #       .rva    function_unwind_info
 882 #
 883 # Reference to functon_unwind_info from .xdata segment is the anchor.
 884 # In case you wonder why references are 32-bit .rvas and not 64-bit
 885 # .quads. References put into these two segments are required to be
 886 # *relative* to the base address of the current binary module, a.k.a.
 887 # image base. No Win64 module, be it .exe or .dll, can be larger than
 888 # 2GB and thus such relative references can be and are accommodated in
 889 # 32 bits.
 890 #
 891 # Having reviewed the example function code, one can argue that "movq
 892 # %rsp,%rax" above is redundant. It is not! Keep in mind that on Unix
 893 # rax would contain an undefined value. If this "offends" you, use
 894 # another register and refrain from modifying rax till magic_point is
 895 # reached, i.e. as if it was a non-volatile register. If more registers
 896 # are required prior [variable] frame setup is completed, note that
 897 # nobody says that you can have only one "magic point." You can
 898 # "liberate" non-volatile registers by denoting last stack off-load
 899 # instruction and reflecting it in finer grade unwind logic in handler.
 900 # After all, isn't it why it's called *language-specific* handler...
 901 #
 902 # Attentive reader can notice that exceptions would be mishandled in
 903 # auto-generated "gear" epilogue. Well, exception effectively can't
 904 # occur there, because if memory area used by it was subject to
 905 # segmentation violation, then it would be raised upon call to the
 906 # function (and as already mentioned be accounted to caller, which is
 907 # not a problem). If you're still not comfortable, then define tail
 908 # "magic point" just prior ret instruction and have handler treat it...
 909 #
 910 # (*)   Note that we're talking about run-time, not debug-time. Lack of
 911 #       unwind information makes debugging hard on both Windows and
 912 #       Unix. "Unlike" referes to the fact that on Unix signal handler
 913 #       will always be invoked, core dumped and appropriate exit code
 914 #       returned to parent (for user notification).