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 61my $flavour = shift; 62my $output = shift; 63if ($flavour =~ /\./) { $output = $flavour; undef $flavour; } 64 65{ my ($stddev,$stdino,@junk)=stat(STDOUT); 66 my ($outdev,$outino,@junk)=stat($output); 67 68 open STDOUT,">$output" || die "can't open $output: $!" 69 if ($stddev!=$outdev || $stdino!=$outino); 70} 71 72my $gas=1; $gas=0 if ($output =~ /\.asm$/); 73my $elf=1; $elf=0 if (!$gas); 74my $win64=0; 75my $prefix=""; 76my $decor=".L"; 77 78my $masmref=8 + 50727*2**-32; # 8.00.50727 shipped with VS2005 79my $masm=0; 80my $PTR=" PTR"; 81 82my $nasmref=2.03; 83my $nasm=0; 84 85if ($flavour eq "mingw64") { $gas=1; $elf=0; $win64=1; 86 $prefix=`echo __USER_LABEL_PREFIX__ | $ENV{CC} -E -P -`; 87 chomp($prefix); 88 } 89elsif ($flavour eq "macosx") { $gas=1; $elf=0; $prefix="_"; $decor="L\$"; } 90elsif ($flavour eq "masm") { $gas=0; $elf=0; $masm=$masmref; $win64=1; $decor="\$L\$"; } 91elsif ($flavour eq "nasm") { $gas=0; $elf=0; $nasm=$nasmref; $win64=1; $decor="\$L\$"; $PTR=""; } 92elsif (!$gas) 93{ if ($ENV{ASM} =~ m/nasm/ && `nasm -v` =~ m/version ([0-9]+)\.([0-9]+)/i) 94 { $nasm = $1 + $2*0.01; $PTR=""; } 95 elsif (`ml64 2>&1` =~ m/Version ([0-9]+)\.([0-9]+)(\.([0-9]+))?/) 96 { $masm = $1 + $2*2**-16 + $4*2**-32; } 97 die "no assembler found on %PATH" if (!($nasm || $masm)); 98 $win64=1; 99 $elf=0; 100 $decor="\$L\$"; 101} 102 103my $current_segment; 104my $current_function; 105my %globals; 106 107{ package opcode; # pick up opcodes 108 sub re { 109 my $self = shift; # single instance in enough... 110 local *line = shift; 111 undef $ret; 112 113 if ($line =~ /^([a-z][a-z0-9]*)/i) { 114 $self->{op} = $1; 115 $ret = $self; 116 $line = substr($line,@+[0]); $line =~ s/^\s+//; 117 118 undef $self->{sz}; 119 if ($self->{op} =~ /^(movz)b.*/) { # movz is pain... 120 $self->{op} = $1; 121 $self->{sz} = "b"; 122 } elsif ($self->{op} =~ /call|jmp/) { 123 $self->{sz} = ""; 124 } elsif ($self->{op} =~ /^p/ && $' !~ /^(ush|op)/) { # SSEn 125 $self->{sz} = ""; 126 } elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) { 127 $self->{op} = $1; 128 $self->{sz} = $2; 129 } 130 } 131 $ret; 132 } 133 sub size { 134 my $self = shift; 135 my $sz = shift; 136 $self->{sz} = $sz if (defined($sz) && !defined($self->{sz})); 137 $self->{sz}; 138 } 139 sub out { 140 my $self = shift; 141 if ($gas) { 142 if ($self->{op} eq "movz") { # movz is pain... 143 sprintf "%s%s%s",$self->{op},$self->{sz},shift; 144 } elsif ($self->{op} =~ /^set/) { 145 "$self->{op}"; 146 } elsif ($self->{op} eq "ret") { 147 my $epilogue = ""; 148 if ($win64 && $current_function->{abi} eq "svr4") { 149 $epilogue = "movq 8(%rsp),%rdi\n\t" . 150 "movq 16(%rsp),%rsi\n\t"; 151 } 152 $epilogue . ".byte 0xf3,0xc3"; 153 } elsif ($self->{op} eq "call" && !$elf && $current_segment eq ".init") { 154 ".p2align\t3\n\t.quad"; 155 } else { 156 "$self->{op}$self->{sz}"; 157 } 158 } else { 159 $self->{op} =~ s/^movz/movzx/; 160 if ($self->{op} eq "ret") { 161 $self->{op} = ""; 162 if ($win64 && $current_function->{abi} eq "svr4") { 163 $self->{op} = "mov rdi,QWORD${PTR}[8+rsp]\t;WIN64 epilogue\n\t". 164 "mov rsi,QWORD${PTR}[16+rsp]\n\t"; 165 } 166 $self->{op} .= "DB\t0F3h,0C3h\t\t;repret"; 167 } elsif ($self->{op} =~ /^(pop|push)f/) { 168 $self->{op} .= $self->{sz}; 169 } elsif ($self->{op} eq "call" && $current_segment eq ".CRT\$XCU") { 170 $self->{op} = "ALIGN\t8\n\tDQ"; 171 } 172 $self->{op}; 173 } 174 } 175 sub mnemonic { 176 my $self=shift; 177 my $op=shift; 178 $self->{op}=$op if (defined($op)); 179 $self->{op}; 180 } 181} 182{ package const; # pick up constants, which start with $ 183 sub re { 184 my $self = shift; # single instance in enough... 185 local *line = shift; 186 undef $ret; 187 188 if ($line =~ /^\$([^,]+)/) { 189 $self->{value} = $1; 190 $ret = $self; 191 $line = substr($line,@+[0]); $line =~ s/^\s+//; 192 } 193 $ret; 194 } 195 sub out { 196 my $self = shift; 197 198 if ($gas) { 199 # Solaris /usr/ccs/bin/as can't handle multiplications 200 # in $self->{value} 201 $self->{value} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi; 202 $self->{value} =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg; 203 sprintf "\$%s",$self->{value}; 204 } else { 205 $self->{value} =~ s/(0b[0-1]+)/oct($1)/eig; 206 $self->{value} =~ s/0x([0-9a-f]+)/0$1h/ig if ($masm); 207 sprintf "%s",$self->{value}; 208 } 209 } 210} 211{ package ea; # pick up effective addresses: expr(%reg,%reg,scale) 212 sub re { 213 my $self = shift; # single instance in enough... 214 local *line = shift; 215 undef $ret; 216 217 # optional * ---vvv--- appears in indirect jmp/call 218 if ($line =~ /^(\*?)([^\(,]*)\(([%\w,]+)\)/) { 219 $self->{asterisk} = $1; 220 $self->{label} = $2; 221 ($self->{base},$self->{index},$self->{scale})=split(/,/,$3); 222 $self->{scale} = 1 if (!defined($self->{scale})); 223 $ret = $self; 224 $line = substr($line,@+[0]); $line =~ s/^\s+//; 225 226 if ($win64 && $self->{label} =~ s/\@GOTPCREL//) { 227 die if (opcode->mnemonic() ne "mov"); 228 opcode->mnemonic("lea"); 229 } 230 $self->{base} =~ s/^%//; 231 $self->{index} =~ s/^%// if (defined($self->{index})); 232 } 233 $ret; 234 } 235 sub size {} 236 sub out { 237 my $self = shift; 238 my $sz = shift; 239 240 $self->{label} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; 241 $self->{label} =~ s/\.L/$decor/g; 242 243 # Silently convert all EAs to 64-bit. This is required for 244 # elder GNU assembler and results in more compact code, 245 # *but* most importantly AES module depends on this feature! 246 $self->{index} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; 247 $self->{base} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; 248 249 if ($gas) { 250 # Solaris /usr/ccs/bin/as can't handle multiplications 251 # in $self->{label}, new gas requires sign extension... 252 use integer; 253 $self->{label} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi; 254 $self->{label} =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg; 255 $self->{label} =~ s/([0-9]+)/$1<<32>>32/eg; 256 $self->{label} =~ s/^___imp_/__imp__/ if ($flavour eq "mingw64"); 257 258 if (defined($self->{index})) { 259 sprintf "%s%s(%%%s,%%%s,%d)",$self->{asterisk}, 260 $self->{label},$self->{base}, 261 $self->{index},$self->{scale}; 262 } else { 263 sprintf "%s%s(%%%s)", $self->{asterisk},$self->{label},$self->{base}; 264 } 265 } else { 266 %szmap = ( b=>"BYTE$PTR", w=>"WORD$PTR", l=>"DWORD$PTR", q=>"QWORD$PTR" ); 267 268 $self->{label} =~ s/\./\$/g; 269 $self->{label} =~ s/(?<![\w\$\.])0x([0-9a-f]+)/0$1h/ig; 270 $self->{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/); 271 $sz="q" if ($self->{asterisk}); 272 273 if (defined($self->{index})) { 274 sprintf "%s[%s%s*%d+%s]",$szmap{$sz}, 275 $self->{label}?"$self->{label}+":"", 276 $self->{index},$self->{scale}, 277 $self->{base}; 278 } elsif ($self->{base} eq "rip") { 279 sprintf "%s[%s]",$szmap{$sz},$self->{label}; 280 } else { 281 sprintf "%s[%s%s]",$szmap{$sz}, 282 $self->{label}?"$self->{label}+":"", 283 $self->{base}; 284 } 285 } 286 } 287} 288{ package register; # pick up registers, which start with %. 289 sub re { 290 my $class = shift; # muliple instances... 291 my $self = {}; 292 local *line = shift; 293 undef $ret; 294 295 # optional * ---vvv--- appears in indirect jmp/call 296 if ($line =~ /^(\*?)%(\w+)/) { 297 bless $self,$class; 298 $self->{asterisk} = $1; 299 $self->{value} = $2; 300 $ret = $self; 301 $line = substr($line,@+[0]); $line =~ s/^\s+//; 302 } 303 $ret; 304 } 305 sub size { 306 my $self = shift; 307 undef $ret; 308 309 if ($self->{value} =~ /^r[\d]+b$/i) { $ret="b"; } 310 elsif ($self->{value} =~ /^r[\d]+w$/i) { $ret="w"; } 311 elsif ($self->{value} =~ /^r[\d]+d$/i) { $ret="l"; } 312 elsif ($self->{value} =~ /^r[\w]+$/i) { $ret="q"; } 313 elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; } 314 elsif ($self->{value} =~ /^[\w]{2}l$/i) { $ret="b"; } 315 elsif ($self->{value} =~ /^[\w]{2}$/i) { $ret="w"; } 316 elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; } 317 318 $ret; 319 } 320 sub out { 321 my $self = shift; 322 if ($gas) { sprintf "%s%%%s",$self->{asterisk},$self->{value}; } 323 else { $self->{value}; } 324 } 325} 326{ package label; # pick up labels, which end with : 327 sub re { 328 my $self = shift; # single instance is enough... 329 local *line = shift; 330 undef $ret; 331 332 if ($line =~ /(^[\.\w]+)\:/) { 333 $self->{value} = $1; 334 $ret = $self; 335 $line = substr($line,@+[0]); $line =~ s/^\s+//; 336 337 $self->{value} =~ s/^\.L/$decor/; 338 } 339 $ret; 340 } 341 sub out { 342 my $self = shift; 343 344 if ($gas) { 345 my $func = ($globals{$self->{value}} or $self->{value}) . ":"; 346 if ($win64 && 347 $current_function->{name} eq $self->{value} && 348 $current_function->{abi} eq "svr4") { 349 $func .= "\n"; 350 $func .= " movq %rdi,8(%rsp)\n"; 351 $func .= " movq %rsi,16(%rsp)\n"; 352 $func .= " movq %rsp,%rax\n"; 353 $func .= "${decor}SEH_begin_$current_function->{name}:\n"; 354 my $narg = $current_function->{narg}; 355 $narg=6 if (!defined($narg)); 356 $func .= " movq %rcx,%rdi\n" if ($narg>0); 357 $func .= " movq %rdx,%rsi\n" if ($narg>1); 358 $func .= " movq %r8,%rdx\n" if ($narg>2); 359 $func .= " movq %r9,%rcx\n" if ($narg>3); 360 $func .= " movq 40(%rsp),%r8\n" if ($narg>4); 361 $func .= " movq 48(%rsp),%r9\n" if ($narg>5); 362 } 363 $func; 364 } elsif ($self->{value} ne "$current_function->{name}") { 365 $self->{value} .= ":" if ($masm && $ret!~m/^\$/); 366 $self->{value} . ":"; 367 } elsif ($win64 && $current_function->{abi} eq "svr4") { 368 my $func = "$current_function->{name}" . 369 ($nasm ? ":" : "\tPROC $current_function->{scope}") . 370 "\n"; 371 $func .= " mov QWORD${PTR}[8+rsp],rdi\t;WIN64 prologue\n"; 372 $func .= " mov QWORD${PTR}[16+rsp],rsi\n"; 373 $func .= " mov rax,rsp\n"; 374 $func .= "${decor}SEH_begin_$current_function->{name}:"; 375 $func .= ":" if ($masm); 376 $func .= "\n"; 377 my $narg = $current_function->{narg}; 378 $narg=6 if (!defined($narg)); 379 $func .= " mov rdi,rcx\n" if ($narg>0); 380 $func .= " mov rsi,rdx\n" if ($narg>1); 381 $func .= " mov rdx,r8\n" if ($narg>2); 382 $func .= " mov rcx,r9\n" if ($narg>3); 383 $func .= " mov r8,QWORD${PTR}[40+rsp]\n" if ($narg>4); 384 $func .= " mov r9,QWORD${PTR}[48+rsp]\n" if ($narg>5); 385 $func .= "\n"; 386 } else { 387 "$current_function->{name}". 388 ($nasm ? ":" : "\tPROC $current_function->{scope}"); 389 } 390 } 391} 392{ package expr; # pick up expressioins 393 sub re { 394 my $self = shift; # single instance is enough... 395 local *line = shift; 396 undef $ret; 397 398 if ($line =~ /(^[^,]+)/) { 399 $self->{value} = $1; 400 $ret = $self; 401 $line = substr($line,@+[0]); $line =~ s/^\s+//; 402 403 $self->{value} =~ s/\@PLT// if (!$elf); 404 $self->{value} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; 405 $self->{value} =~ s/\.L/$decor/g; 406 } 407 $ret; 408 } 409 sub out { 410 my $self = shift; 411 if ($nasm && opcode->mnemonic()=~m/^j/) { 412 "NEAR ".$self->{value}; 413 } else { 414 $self->{value}; 415 } 416 } 417} 418{ package directive; # pick up directives, which start with . 419 sub re { 420 my $self = shift; # single instance is enough... 421 local *line = shift; 422 undef $ret; 423 my $dir; 424 my %opcode = # lea 2f-1f(%rip),%dst; 1: nop; 2: 425 ( "%rax"=>0x01058d48, "%rcx"=>0x010d8d48, 426 "%rdx"=>0x01158d48, "%rbx"=>0x011d8d48, 427 "%rsp"=>0x01258d48, "%rbp"=>0x012d8d48, 428 "%rsi"=>0x01358d48, "%rdi"=>0x013d8d48, 429 "%r8" =>0x01058d4c, "%r9" =>0x010d8d4c, 430 "%r10"=>0x01158d4c, "%r11"=>0x011d8d4c, 431 "%r12"=>0x01258d4c, "%r13"=>0x012d8d4c, 432 "%r14"=>0x01358d4c, "%r15"=>0x013d8d4c ); 433 434 if ($line =~ /^\s*(\.\w+)/) { 435 $dir = $1; 436 $ret = $self; 437 undef $self->{value}; 438 $line = substr($line,@+[0]); $line =~ s/^\s+//; 439 440 SWITCH: for ($dir) { 441 /\.picmeup/ && do { if ($line =~ /(%r[\w]+)/i) { 442 $dir="\t.long"; 443 $line=sprintf "0x%x,0x90000000",$opcode{$1}; 444 } 445 last; 446 }; 447 /\.global|\.globl|\.extern/ 448 && do { $globals{$line} = $prefix . $line; 449 $line = $globals{$line} if ($prefix); 450 last; 451 }; 452 /\.type/ && do { ($sym,$type,$narg) = split(',',$line); 453 if ($type eq "\@function") { 454 undef $current_function; 455 $current_function->{name} = $sym; 456 $current_function->{abi} = "svr4"; 457 $current_function->{narg} = $narg; 458 $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE"; 459 } elsif ($type eq "\@abi-omnipotent") { 460 undef $current_function; 461 $current_function->{name} = $sym; 462 $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE"; 463 } 464 $line =~ s/\@abi\-omnipotent/\@function/; 465 $line =~ s/\@function.*/\@function/; 466 last; 467 }; 468 /\.asciz/ && do { if ($line =~ /^"(.*)"$/) { 469 $dir = ".byte"; 470 $line = join(",",unpack("C*",$1),0); 471 } 472 last; 473 }; 474 /\.rva|\.long|\.quad/ 475 && do { $line =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; 476 $line =~ s/\.L/$decor/g; 477 last; 478 }; 479 } 480 481 if ($gas) { 482 $self->{value} = $dir . "\t" . $line; 483 484 if ($dir =~ /\.extern/) { 485 $self->{value} = ""; # swallow extern 486 } elsif (!$elf && $dir =~ /\.type/) { 487 $self->{value} = ""; 488 $self->{value} = ".def\t" . ($globals{$1} or $1) . ";\t" . 489 (defined($globals{$1})?".scl 2;":".scl 3;") . 490 "\t.type 32;\t.endef" 491 if ($win64 && $line =~ /([^,]+),\@function/); 492 } elsif (!$elf && $dir =~ /\.size/) { 493 $self->{value} = ""; 494 if (defined($current_function)) { 495 $self->{value} .= "${decor}SEH_end_$current_function->{name}:" 496 if ($win64 && $current_function->{abi} eq "svr4"); 497 undef $current_function; 498 } 499 } elsif (!$elf && $dir =~ /\.align/) { 500 $self->{value} = ".p2align\t" . (log($line)/log(2)); 501 } elsif ($dir eq ".section") { 502 $current_segment=$line; 503 if (!$elf && $current_segment eq ".init") { 504 if ($flavour eq "macosx") { $self->{value} = ".mod_init_func"; } 505 elsif ($flavour eq "mingw64") { $self->{value} = ".section\t.ctors"; } 506 } 507 } elsif ($dir =~ /\.(text|data)/) { 508 $current_segment=".$1"; 509 } 510 $line = ""; 511 return $self; 512 } 513 514 # non-gas case or nasm/masm 515 SWITCH: for ($dir) { 516 /\.text/ && do { my $v=undef; 517 if ($nasm) { 518 $v="section .text code align=64\n"; 519 } else { 520 $v="$current_segment\tENDS\n" if ($current_segment); 521 $current_segment = ".text\$"; 522 $v.="$current_segment\tSEGMENT "; 523 $v.=$masm>=$masmref ? "ALIGN(64)" : "PAGE"; 524 $v.=" 'CODE'"; 525 } 526 $self->{value} = $v; 527 last; 528 }; 529 /\.data/ && do { my $v=undef; 530 if ($nasm) { 531 $v="section .data data align=8\n"; 532 } else { 533 $v="$current_segment\tENDS\n" if ($current_segment); 534 $current_segment = "_DATA"; 535 $v.="$current_segment\tSEGMENT"; 536 } 537 $self->{value} = $v; 538 last; 539 }; 540 /\.section/ && do { my $v=undef; 541 $line =~ s/([^,]*).*/$1/; 542 $line = ".CRT\$XCU" if ($line eq ".init"); 543 if ($nasm) { 544 $v="section $line"; 545 if ($line=~/\.([px])data/) { 546 $v.=" rdata align="; 547 $v.=$1 eq "p"? 4 : 8; 548 } 549 } else { 550 $v="$current_segment\tENDS\n" if ($current_segment); 551 $v.="$line\tSEGMENT"; 552 if ($line=~/\.([px])data/) { 553 $v.=" READONLY"; 554 $v.=" ALIGN(".($1 eq "p" ? 4 : 8).")" if ($masm>=$masmref); 555 } 556 } 557 $current_segment = $line; 558 $self->{value} = $v; 559 last; 560 }; 561 /\.extern/ && do { $self->{value} = "EXTERN\t".$line; 562 $self->{value} .= ":NEAR" if ($masm); 563 last; 564 }; 565 /\.globl|.global/ 566 && do { $self->{value} = $masm?"PUBLIC":"global"; 567 $self->{value} .= "\t".$line; 568 last; 569 }; 570 /\.size/ && do { if (defined($current_function)) { 571 undef $self->{value}; 572 if ($current_function->{abi} eq "svr4") { 573 $self->{value}="${decor}SEH_end_$current_function->{name}:"; 574 $self->{value}.=":\n" if($masm); 575 } 576 $self->{value}.="$current_function->{name}\tENDP" if($masm); 577 undef $current_function; 578 } 579 last; 580 }; 581 /\.align/ && do { $self->{value} = "ALIGN\t".$line; last; }; 582 /\.(value|long|rva|quad)/ 583 && do { my $sz = substr($1,0,1); 584 my @arr = split(/,\s*/,$line); 585 my $last = pop(@arr); 586 my $conv = sub { my $var=shift; 587 $var=~s/^(0b[0-1]+)/oct($1)/eig; 588 $var=~s/^0x([0-9a-f]+)/0$1h/ig if ($masm); 589 if ($sz eq "D" && ($current_segment=~/.[px]data/ || $dir eq ".rva")) 590 { $var=~s/([_a-z\$\@][_a-z0-9\$\@]*)/$nasm?"$1 wrt ..imagebase":"imagerel $1"/egi; } 591 $var; 592 }; 593 594 $sz =~ tr/bvlrq/BWDDQ/; 595 $self->{value} = "\tD$sz\t"; 596 for (@arr) { $self->{value} .= &$conv($_).","; } 597 $self->{value} .= &$conv($last); 598 last; 599 }; 600 /\.byte/ && do { my @str=split(/,\s*/,$line); 601 map(s/(0b[0-1]+)/oct($1)/eig,@str); 602 map(s/0x([0-9a-f]+)/0$1h/ig,@str) if ($masm); 603 while ($#str>15) { 604 $self->{value}.="DB\t" 605 .join(",",@str[0..15])."\n"; 606 foreach (0..15) { shift @str; } 607 } 608 $self->{value}.="DB\t" 609 .join(",",@str) if (@str); 610 last; 611 }; 612 } 613 $line = ""; 614 } 615 616 $ret; 617 } 618 sub out { 619 my $self = shift; 620 $self->{value}; 621 } 622} 623 624if ($nasm) { 625 print <<___; 626default rel 627___ 628} elsif ($masm) { 629 print <<___; 630OPTION DOTNAME 631___ 632} 633while($line=<>) { 634 635 chomp($line); 636 637 $line =~ s|[#!].*$||; # get rid of asm-style comments... 638 $line =~ s|/\*.*\*/||; # ... and C-style comments... 639 $line =~ s|^\s+||; # ... and skip white spaces in beginning 640 641 undef $label; 642 undef $opcode; 643 undef $sz; 644 undef @args; 645 646 if ($label=label->re(\$line)) { print $label->out(); } 647 648 if (directive->re(\$line)) { 649 printf "%s",directive->out(); 650 } elsif ($opcode=opcode->re(\$line)) { ARGUMENT: while (1) { 651 my $arg; 652 653 if ($arg=register->re(\$line)) { opcode->size($arg->size()); } 654 elsif ($arg=const->re(\$line)) { } 655 elsif ($arg=ea->re(\$line)) { } 656 elsif ($arg=expr->re(\$line)) { } 657 else { last ARGUMENT; } 658 659 push @args,$arg; 660 661 last ARGUMENT if ($line !~ /^,/); 662 663 $line =~ s/^,\s*//; 664 } # ARGUMENT: 665 666 $sz=opcode->size(); 667 668 if ($#args>=0) { 669 my $insn; 670 if ($gas) { 671 $insn = $opcode->out($#args>=1?$args[$#args]->size():$sz); 672 } else { 673 $insn = $opcode->out(); 674 $insn .= $sz if (map($_->out() =~ /x?mm/,@args)); 675 @args = reverse(@args); 676 undef $sz if ($nasm && $opcode->mnemonic() eq "lea"); 677 } 678 printf "\t%s\t%s",$insn,join(",",map($_->out($sz),@args)); 679 } else { 680 printf "\t%s",$opcode->out(); 681 } 682 } 683 684 print $line,"\n"; 685} 686 687print "\n$current_segment\tENDS\n" if ($current_segment && $masm); 688print "END\n" if ($masm); 689 690close STDOUT; 691 692 ################################################# 693# Cross-reference x86_64 ABI "card" 694# 695# Unix Win64 696# %rax * * 697# %rbx - - 698# %rcx #4 #1 699# %rdx #3 #2 700# %rsi #2 - 701# %rdi #1 - 702# %rbp - - 703# %rsp - - 704# %r8 #5 #3 705# %r9 #6 #4 706# %r10 * * 707# %r11 * * 708# %r12 - - 709# %r13 - - 710# %r14 - - 711# %r15 - - 712# 713# (*) volatile register 714# (-) preserved by callee 715# (#) Nth argument, volatile 716# 717# In Unix terms top of stack is argument transfer area for arguments 718# which could not be accomodated in registers. Or in other words 7th 719# [integer] argument resides at 8(%rsp) upon function entry point. 720# 128 bytes above %rsp constitute a "red zone" which is not touched 721# by signal handlers and can be used as temporal storage without 722# allocating a frame. 723# 724# In Win64 terms N*8 bytes on top of stack is argument transfer area, 725# which belongs to/can be overwritten by callee. N is the number of 726# arguments passed to callee, *but* not less than 4! This means that 727# upon function entry point 5th argument resides at 40(%rsp), as well 728# as that 32 bytes from 8(%rsp) can always be used as temporal 729# storage [without allocating a frame]. One can actually argue that 730# one can assume a "red zone" above stack pointer under Win64 as well. 731# Point is that at apparently no occasion Windows kernel would alter 732# the area above user stack pointer in true asynchronous manner... 733# 734# All the above means that if assembler programmer adheres to Unix 735# register and stack layout, but disregards the "red zone" existense, 736# it's possible to use following prologue and epilogue to "gear" from 737# Unix to Win64 ABI in leaf functions with not more than 6 arguments. 738# 739# omnipotent_function: 740# ifdef WIN64 741# movq %rdi,8(%rsp) 742# movq %rsi,16(%rsp) 743# movq %rcx,%rdi ; if 1st argument is actually present 744# movq %rdx,%rsi ; if 2nd argument is actually ... 745# movq %r8,%rdx ; if 3rd argument is ... 746# movq %r9,%rcx ; if 4th argument ... 747# movq 40(%rsp),%r8 ; if 5th ... 748# movq 48(%rsp),%r9 ; if 6th ... 749# endif 750# ... 751# ifdef WIN64 752# movq 8(%rsp),%rdi 753# movq 16(%rsp),%rsi 754# endif 755# ret 756# 757 ################################################# 758# Win64 SEH, Structured Exception Handling. 759# 760# Unlike on Unix systems(*) lack of Win64 stack unwinding information 761# has undesired side-effect at run-time: if an exception is raised in 762# assembler subroutine such as those in question (basically we're 763# referring to segmentation violations caused by malformed input 764# parameters), the application is briskly terminated without invoking 765# any exception handlers, most notably without generating memory dump 766# or any user notification whatsoever. This poses a problem. It's 767# possible to address it by registering custom language-specific 768# handler that would restore processor context to the state at 769# subroutine entry point and return "exception is not handled, keep 770# unwinding" code. Writing such handler can be a challenge... But it's 771# doable, though requires certain coding convention. Consider following 772# snippet: 773# 774# .type function,@function 775# function: 776# movq %rsp,%rax # copy rsp to volatile register 777# pushq %r15 # save non-volatile registers 778# pushq %rbx 779# pushq %rbp 780# movq %rsp,%r11 781# subq %rdi,%r11 # prepare [variable] stack frame 782# andq $-64,%r11 783# movq %rax,0(%r11) # check for exceptions 784# movq %r11,%rsp # allocate [variable] stack frame 785# movq %rax,0(%rsp) # save original rsp value 786# magic_point: 787# ... 788# movq 0(%rsp),%rcx # pull original rsp value 789# movq -24(%rcx),%rbp # restore non-volatile registers 790# movq -16(%rcx),%rbx 791# movq -8(%rcx),%r15 792# movq %rcx,%rsp # restore original rsp 793# ret 794# .size function,.-function 795# 796# The key is that up to magic_point copy of original rsp value remains 797# in chosen volatile register and no non-volatile register, except for 798# rsp, is modified. While past magic_point rsp remains constant till 799# the very end of the function. In this case custom language-specific 800# exception handler would look like this: 801# 802# EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame, 803# CONTEXT *context,DISPATCHER_CONTEXT *disp) 804# { ULONG64 *rsp = (ULONG64 *)context->Rax; 805# if (context->Rip >= magic_point) 806# { rsp = ((ULONG64 **)context->Rsp)[0]; 807# context->Rbp = rsp[-3]; 808# context->Rbx = rsp[-2]; 809# context->R15 = rsp[-1]; 810# } 811# context->Rsp = (ULONG64)rsp; 812# context->Rdi = rsp[1]; 813# context->Rsi = rsp[2]; 814# 815# memcpy (disp->ContextRecord,context,sizeof(CONTEXT)); 816# RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase, 817# dips->ControlPc,disp->FunctionEntry,disp->ContextRecord, 818# &disp->HandlerData,&disp->EstablisherFrame,NULL); 819# return ExceptionContinueSearch; 820# } 821# 822# It's appropriate to implement this handler in assembler, directly in 823# function's module. In order to do that one has to know members' 824# offsets in CONTEXT and DISPATCHER_CONTEXT structures and some constant 825# values. Here they are: 826# 827# CONTEXT.Rax 120 828# CONTEXT.Rcx 128 829# CONTEXT.Rdx 136 830# CONTEXT.Rbx 144 831# CONTEXT.Rsp 152 832# CONTEXT.Rbp 160 833# CONTEXT.Rsi 168 834# CONTEXT.Rdi 176 835# CONTEXT.R8 184 836# CONTEXT.R9 192 837# CONTEXT.R10 200 838# CONTEXT.R11 208 839# CONTEXT.R12 216 840# CONTEXT.R13 224 841# CONTEXT.R14 232 842# CONTEXT.R15 240 843# CONTEXT.Rip 248 844# CONTEXT.Xmm6 512 845# sizeof(CONTEXT) 1232 846# DISPATCHER_CONTEXT.ControlPc 0 847# DISPATCHER_CONTEXT.ImageBase 8 848# DISPATCHER_CONTEXT.FunctionEntry 16 849# DISPATCHER_CONTEXT.EstablisherFrame 24 850# DISPATCHER_CONTEXT.TargetIp 32 851# DISPATCHER_CONTEXT.ContextRecord 40 852# DISPATCHER_CONTEXT.LanguageHandler 48 853# DISPATCHER_CONTEXT.HandlerData 56 854# UNW_FLAG_NHANDLER 0 855# ExceptionContinueSearch 1 856# 857# In order to tie the handler to the function one has to compose 858# couple of structures: one for .xdata segment and one for .pdata. 859# 860# UNWIND_INFO structure for .xdata segment would be 861# 862# function_unwind_info: 863# .byte 9,0,0,0 864# .rva handler 865# 866# This structure designates exception handler for a function with 867# zero-length prologue, no stack frame or frame register. 868# 869# To facilitate composing of .pdata structures, auto-generated "gear" 870# prologue copies rsp value to rax and denotes next instruction with 871# .LSEH_begin_{function_name} label. This essentially defines the SEH 872# styling rule mentioned in the beginning. Position of this label is 873# chosen in such manner that possible exceptions raised in the "gear" 874# prologue would be accounted to caller and unwound from latter's frame. 875# End of function is marked with respective .LSEH_end_{function_name} 876# label. To summarize, .pdata segment would contain 877# 878# .rva .LSEH_begin_function 879# .rva .LSEH_end_function 880# .rva function_unwind_info 881# 882# Reference to functon_unwind_info from .xdata segment is the anchor. 883# In case you wonder why references are 32-bit .rvas and not 64-bit 884# .quads. References put into these two segments are required to be 885# *relative* to the base address of the current binary module, a.k.a. 886# image base. No Win64 module, be it .exe or .dll, can be larger than 887# 2GB and thus such relative references can be and are accommodated in 888# 32 bits. 889# 890# Having reviewed the example function code, one can argue that "movq 891# %rsp,%rax" above is redundant. It is not! Keep in mind that on Unix 892# rax would contain an undefined value. If this "offends" you, use 893# another register and refrain from modifying rax till magic_point is 894# reached, i.e. as if it was a non-volatile register. If more registers 895# are required prior [variable] frame setup is completed, note that 896# nobody says that you can have only one "magic point." You can 897# "liberate" non-volatile registers by denoting last stack off-load 898# instruction and reflecting it in finer grade unwind logic in handler. 899# After all, isn't it why it's called *language-specific* handler... 900# 901# Attentive reader can notice that exceptions would be mishandled in 902# auto-generated "gear" epilogue. Well, exception effectively can't 903# occur there, because if memory area used by it was subject to 904# segmentation violation, then it would be raised upon call to the 905# function (and as already mentioned be accounted to caller, which is 906# not a problem). If you're still not comfortable, then define tail 907# "magic point" just prior ret instruction and have handler treat it... 908# 909# (*) Note that we're talking about run-time, not debug-time. Lack of 910# unwind information makes debugging hard on both Windows and 911# Unix. "Unlike" referes to the fact that on Unix signal handler 912# will always be invoked, core dumped and appropriate exit code 913# returned to parent (for user notification). 914