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 $flavour; } 64 65open STDOUT,">$output" || die "can't open $output: $!" 66 if (defined($output)); 67 68my $gas=1; $gas=0 if ($output =~ /\.asm$/); 69my $elf=1; $elf=0 if (!$gas); 70my $win64=0; 71my $prefix=""; 72my $decor=".L"; 73 74my $masmref=8 + 50727*2**-32; # 8.00.50727 shipped with VS2005 75my $masm=0; 76my $PTR=" PTR"; 77 78my $nasmref=2.03; 79my $nasm=0; 80 81if ($flavour eq "mingw64") { $gas=1; $elf=0; $win64=1; 82 $prefix=`echo __USER_LABEL_PREFIX__ | $ENV{CC} -E -P -`; 83 chomp($prefix); 84 } 85elsif ($flavour eq "macosx") { $gas=1; $elf=0; $prefix="_"; $decor="L\$"; } 86elsif ($flavour eq "masm") { $gas=0; $elf=0; $masm=$masmref; $win64=1; $decor="\$L\$"; } 87elsif ($flavour eq "nasm") { $gas=0; $elf=0; $nasm=$nasmref; $win64=1; $decor="\$L\$"; $PTR=""; } 88elsif (!$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 99my $current_segment; 100my $current_function; 101my %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 $self->{value}; 622 } 623} 624 625if ($nasm) { 626 print <<___; 627default rel 628___ 629} elsif ($masm) { 630 print <<___; 631OPTION DOTNAME 632___ 633} 634while($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 $line,"\n"; 686} 687 688print "\n$current_segment\tENDS\n" if ($current_segment && $masm); 689print "END\n" if ($masm); 690 691close STDOUT; 692 693 ################################################# 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 ################################################# 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). 915