1 #! /usr/bin/env perl 2 # Copyright 2005-2016 The OpenSSL Project Authors. All Rights Reserved. 3 # 4 # Licensed under the OpenSSL license (the "License"). You may not use 5 # this file except in compliance with the License. You can obtain a copy 6 # in the file LICENSE in the source distribution or at 7 # https://www.openssl.org/source/license.html 8 9 10 # Ascetic x86_64 AT&T to MASM/NASM assembler translator by <appro>. 11 # 12 # Why AT&T to MASM and not vice versa? Several reasons. Because AT&T 13 # format is way easier to parse. Because it's simpler to "gear" from 14 # Unix ABI to Windows one [see cross-reference "card" at the end of 15 # file]. Because Linux targets were available first... 16 # 17 # In addition the script also "distills" code suitable for GNU 18 # assembler, so that it can be compiled with more rigid assemblers, 19 # such as Solaris /usr/ccs/bin/as. 20 # 21 # This translator is not designed to convert *arbitrary* assembler 22 # code from AT&T format to MASM one. It's designed to convert just 23 # enough to provide for dual-ABI OpenSSL modules development... 24 # There *are* limitations and you might have to modify your assembler 25 # code or this script to achieve the desired result... 26 # 27 # Currently recognized limitations: 28 # 29 # - can't use multiple ops per line; 30 # 31 # Dual-ABI styling rules. 32 # 33 # 1. Adhere to Unix register and stack layout [see cross-reference 34 # ABI "card" at the end for explanation]. 35 # 2. Forget about "red zone," stick to more traditional blended 36 # stack frame allocation. If volatile storage is actually required 37 # that is. If not, just leave the stack as is. 38 # 3. Functions tagged with ".type name,@function" get crafted with 39 # unified Win64 prologue and epilogue automatically. If you want 40 # to take care of ABI differences yourself, tag functions as 41 # ".type name,@abi-omnipotent" instead. 42 # 4. To optimize the Win64 prologue you can specify number of input 43 # arguments as ".type name,@function,N." Keep in mind that if N is 44 # larger than 6, then you *have to* write "abi-omnipotent" code, 45 # because >6 cases can't be addressed with unified prologue. 46 # 5. Name local labels as .L*, do *not* use dynamic labels such as 1: 47 # (sorry about latter). 48 # 6. Don't use [or hand-code with .byte] "rep ret." "ret" mnemonic is 49 # required to identify the spots, where to inject Win64 epilogue! 50 # But on the pros, it's then prefixed with rep automatically:-) 51 # 7. Stick to explicit ip-relative addressing. If you have to use 52 # GOTPCREL addressing, stick to mov symbol@GOTPCREL(%rip),%r??. 53 # Both are recognized and translated to proper Win64 addressing 54 # modes. 55 # 56 # 8. In order to provide for structured exception handling unified 57 # Win64 prologue copies %rsp value to %rax. For further details 58 # see SEH paragraph at the end. 59 # 9. .init segment is allowed to contain calls to functions only. 60 # a. If function accepts more than 4 arguments *and* >4th argument 61 # is declared as non 64-bit value, do clear its upper part. 62 64 65 use strict; 66 67 my $flavour = shift; 68 my $output = shift; 69 if ($flavour =~ /\./) { $output = $flavour; undef $flavour; } 70 71 open STDOUT,">$output" || die "can't open $output: $!" 72 if (defined($output)); 73 74 my $gas=1; $gas=0 if ($output =~ /\.asm$/); 75 my $elf=1; $elf=0 if (!$gas); 76 my $win64=0; 77 my $prefix=""; 78 my $decor=".L"; 79 80 my $masmref=8 + 50727*2**-32; # 8.00.50727 shipped with VS2005 81 my $masm=0; 82 my $PTR=" PTR"; 83 84 my $nasmref=2.03; 85 my $nasm=0; 86 87 if ($flavour eq "mingw64") { $gas=1; $elf=0; $win64=1; 88 # TODO(davidben): Before supporting the 89 # mingw64 perlasm flavour, do away with this 90 # environment variable check. 91 die "mingw64 not supported"; 92 $prefix=`echo __USER_LABEL_PREFIX__ | $ENV{CC} -E -P -`; 93 $prefix =~ s|\R$||; # Better chomp 94 } 95 elsif ($flavour eq "macosx") { $gas=1; $elf=0; $prefix="_"; $decor="L\$"; } 96 elsif ($flavour eq "masm") { $gas=0; $elf=0; $masm=$masmref; $win64=1; $decor="\$L\$"; } 97 elsif ($flavour eq "nasm") { $gas=0; $elf=0; $nasm=$nasmref; $win64=1; $decor="\$L\$"; $PTR=""; } 98 elsif (!$gas) { die "unknown flavour $flavour"; } 99 100 my $current_segment; 101 my $current_function; 102 my %globals; 103 104 { package opcode; # pick up opcodes 105 sub re { 106 my ($class, $line) = @_; 107 my $self = {}; 108 my $ret; 109 110 if ($$line =~ /^([a-z][a-z0-9]*)/i) { 111 bless $self,$class; 112 $self->{op} = $1; 113 $ret = $self; 114 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 115 116 undef $self->{sz}; 117 if ($self->{op} =~ /^(movz)x?([bw]).*/) { # movz is pain... 118 $self->{op} = $1; 119 $self->{sz} = $2; 120 } elsif ($self->{op} =~ /call|jmp/) { 121 $self->{sz} = ""; 122 } elsif ($self->{op} =~ /^p/ && $' !~ /^(ush|op|insrw)/) { # SSEn 123 $self->{sz} = ""; 124 } elsif ($self->{op} =~ /^[vk]/) { # VEX or k* such as kmov 125 $self->{sz} = ""; 126 } elsif ($self->{op} =~ /mov[dq]/ && $$line =~ /%xmm/) { 127 $self->{sz} = ""; 128 } elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) { 129 $self->{op} = $1; 130 $self->{sz} = $2; 131 } 132 } 133 $ret; 134 } 135 sub size { 136 my ($self, $sz) = @_; 137 $self->{sz} = $sz if (defined($sz) && !defined($self->{sz})); 138 $self->{sz}; 139 } 140 sub out { 141 my $self = shift; 142 if ($gas) { 143 if ($self->{op} eq "movz") { # movz is pain... 144 sprintf "%s%s%s",$self->{op},$self->{sz},shift; 145 } elsif ($self->{op} =~ /^set/) { 146 "$self->{op}"; 147 } elsif ($self->{op} eq "ret") { 148 my $epilogue = ""; 149 if ($win64 && $current_function->{abi} eq "svr4") { 150 $epilogue = "movq 8(%rsp),%rdi\n\t" . 151 "movq 16(%rsp),%rsi\n\t"; 152 } 153 $epilogue . ".byte 0xf3,0xc3"; 154 } elsif ($self->{op} eq "call" && !$elf && $current_segment eq ".init") { 155 ".p2align\t3\n\t.quad"; 156 } else { 157 "$self->{op}$self->{sz}"; 158 } 159 } else { 160 $self->{op} =~ s/^movz/movzx/; 161 if ($self->{op} eq "ret") { 162 $self->{op} = ""; 163 if ($win64 && $current_function->{abi} eq "svr4") { 164 $self->{op} = "mov rdi,QWORD$PTR\[8+rsp\]\t;WIN64 epilogue\n\t". 165 "mov rsi,QWORD$PTR\[16+rsp\]\n\t"; 166 } 167 $self->{op} .= "DB\t0F3h,0C3h\t\t;repret"; 168 } elsif ($self->{op} =~ /^(pop|push)f/) { 169 $self->{op} .= $self->{sz}; 170 } elsif ($self->{op} eq "call" && $current_segment eq ".CRT\$XCU") { 171 $self->{op} = "\tDQ"; 172 } 173 $self->{op}; 174 } 175 } 176 sub mnemonic { 177 my ($self, $op) = @_; 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 ($class, $line) = @_; 185 my $self = {}; 186 my $ret; 187 188 if ($$line =~ /^\$([^,]+)/) { 189 bless $self, $class; 190 $self->{value} = $1; 191 $ret = $self; 192 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 193 } 194 $ret; 195 } 196 sub out { 197 my $self = shift; 198 199 $self->{value} =~ s/\b(0b[0-1]+)/oct($1)/eig; 200 if ($gas) { 201 # Solaris /usr/ccs/bin/as can't handle multiplications 202 # in $self->{value} 203 my $value = $self->{value}; 204 no warnings; # oct might complain about overflow, ignore here... 205 $value =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi; 206 if ($value =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg) { 207 $self->{value} = $value; 208 } 209 sprintf "\$%s",$self->{value}; 210 } else { 211 $self->{value} =~ s/0x([0-9a-f]+)/0$1h/ig if ($masm); 212 sprintf "%s",$self->{value}; 213 } 214 } 215 } 216 { package ea; # pick up effective addresses: expr(%reg,%reg,scale) 217 218 my %szmap = ( b=>"BYTE$PTR", w=>"WORD$PTR", 219 l=>"DWORD$PTR", d=>"DWORD$PTR", 220 q=>"QWORD$PTR", o=>"OWORD$PTR", 221 x=>"XMMWORD$PTR", y=>"YMMWORD$PTR", 222 z=>"ZMMWORD$PTR" ) if (!$gas); 223 224 sub re { 225 my ($class, $line, $opcode) = @_; 226 my $self = {}; 227 my $ret; 228 229 # optional * ----vvv--- appears in indirect jmp/call 230 if ($$line =~ /^(\*?)([^\(,]*)\(([%\w,]+)\)((?:{[^}]+})*)/) { 231 bless $self, $class; 232 $self->{asterisk} = $1; 233 $self->{label} = $2; 234 ($self->{base},$self->{index},$self->{scale})=split(/,/,$3); 235 $self->{scale} = 1 if (!defined($self->{scale})); 236 $self->{opmask} = $4; 237 $ret = $self; 238 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 239 240 if ($win64 && $self->{label} =~ s/\@GOTPCREL//) { 241 die if ($opcode->mnemonic() ne "mov"); 242 $opcode->mnemonic("lea"); 243 } 244 $self->{base} =~ s/^%//; 245 $self->{index} =~ s/^%// if (defined($self->{index})); 246 $self->{opcode} = $opcode; 247 } 248 $ret; 249 } 250 sub size {} 251 sub out { 252 my ($self, $sz) = @_; 253 254 $self->{label} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; 255 $self->{label} =~ s/\.L/$decor/g; 256 257 # Silently convert all EAs to 64-bit. This is required for 258 # elder GNU assembler and results in more compact code, 259 # *but* most importantly AES module depends on this feature! 260 $self->{index} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; 261 $self->{base} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; 262 263 # Solaris /usr/ccs/bin/as can't handle multiplications 264 # in $self->{label}... 265 use integer; 266 $self->{label} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi; 267 $self->{label} =~ s/\b([0-9]+\s*[\*\/\%]\s*[0-9]+)\b/eval($1)/eg; 268 269 # Some assemblers insist on signed presentation of 32-bit 270 # offsets, but sign extension is a tricky business in perl... 271 if ((1<<31)<<1) { 272 $self->{label} =~ s/\b([0-9]+)\b/$1<<32>>32/eg; 273 } else { 274 $self->{label} =~ s/\b([0-9]+)\b/$1>>0/eg; 275 } 276 277 # if base register is %rbp or %r13, see if it's possible to 278 # flip base and index registers [for better performance] 279 if (!$self->{label} && $self->{index} && $self->{scale}==1 && 280 $self->{base} =~ /(rbp|r13)/) { 281 $self->{base} = $self->{index}; $self->{index} = $1; 282 } 283 284 if ($gas) { 285 $self->{label} =~ s/^___imp_/__imp__/ if ($flavour eq "mingw64"); 286 287 if (defined($self->{index})) { 288 sprintf "%s%s(%s,%%%s,%d)%s", 289 $self->{asterisk},$self->{label}, 290 $self->{base}?"%$self->{base}":"", 291 $self->{index},$self->{scale}, 292 $self->{opmask}; 293 } else { 294 sprintf "%s%s(%%%s)%s", $self->{asterisk},$self->{label}, 295 $self->{base},$self->{opmask}; 296 } 297 } else { 298 $self->{label} =~ s/\./\$/g; 299 $self->{label} =~ s/(?<![\w\$\.])0x([0-9a-f]+)/0$1h/ig; 300 $self->{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/); 301 302 my $mnemonic = $self->{opcode}->mnemonic(); 303 ($self->{asterisk}) && ($sz="q") || 304 ($mnemonic =~ /^v?mov([qd])$/) && ($sz=$1) || 305 ($mnemonic =~ /^v?pinsr([qdwb])$/) && ($sz=$1) || 306 ($mnemonic =~ /^vpbroadcast([qdwb])$/) && ($sz=$1) || 307 ($mnemonic =~ /^v(?!perm)[a-z]+[fi]128$/) && ($sz="x"); 308 309 $self->{opmask} =~ s/%(k[0-7])/$1/; 310 311 if (defined($self->{index})) { 312 sprintf "%s[%s%s*%d%s]%s",$szmap{$sz}, 313 $self->{label}?"$self->{label}+":"", 314 $self->{index},$self->{scale}, 315 $self->{base}?"+$self->{base}":"", 316 $self->{opmask}; 317 } elsif ($self->{base} eq "rip") { 318 sprintf "%s[%s]",$szmap{$sz},$self->{label}; 319 } else { 320 sprintf "%s[%s%s]%s", $szmap{$sz}, 321 $self->{label}?"$self->{label}+":"", 322 $self->{base},$self->{opmask}; 323 } 324 } 325 } 326 } 327 { package register; # pick up registers, which start with %. 328 sub re { 329 my ($class, $line, $opcode) = @_; 330 my $self = {}; 331 my $ret; 332 333 # optional * ----vvv--- appears in indirect jmp/call 334 if ($$line =~ /^(\*?)%(\w+)((?:{[^}]+})*)/) { 335 bless $self,$class; 336 $self->{asterisk} = $1; 337 $self->{value} = $2; 338 $self->{opmask} = $3; 339 $opcode->size($self->size()); 340 $ret = $self; 341 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 342 } 343 $ret; 344 } 345 sub size { 346 my $self = shift; 347 my $ret; 348 349 if ($self->{value} =~ /^r[\d]+b$/i) { $ret="b"; } 350 elsif ($self->{value} =~ /^r[\d]+w$/i) { $ret="w"; } 351 elsif ($self->{value} =~ /^r[\d]+d$/i) { $ret="l"; } 352 elsif ($self->{value} =~ /^r[\w]+$/i) { $ret="q"; } 353 elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; } 354 elsif ($self->{value} =~ /^[\w]{2}l$/i) { $ret="b"; } 355 elsif ($self->{value} =~ /^[\w]{2}$/i) { $ret="w"; } 356 elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; } 357 358 $ret; 359 } 360 sub out { 361 my $self = shift; 362 if ($gas) { sprintf "%s%%%s%s", $self->{asterisk}, 363 $self->{value}, 364 $self->{opmask}; } 365 else { $self->{opmask} =~ s/%(k[0-7])/$1/; 366 $self->{value}.$self->{opmask}; } 367 } 368 } 369 { package label; # pick up labels, which end with : 370 sub re { 371 my ($class, $line) = @_; 372 my $self = {}; 373 my $ret; 374 375 if ($$line =~ /(^[\.\w]+)\:/) { 376 bless $self,$class; 377 $self->{value} = $1; 378 $ret = $self; 379 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 380 381 $self->{value} =~ s/^\.L/$decor/; 382 } 383 $ret; 384 } 385 sub out { 386 my $self = shift; 387 388 if ($gas) { 389 my $func = ($globals{$self->{value}} or $self->{value}) . ":"; 390 if ($win64 && $current_function->{name} eq $self->{value} 391 && $current_function->{abi} eq "svr4") { 392 $func .= "\n"; 393 $func .= " movq %rdi,8(%rsp)\n"; 394 $func .= " movq %rsi,16(%rsp)\n"; 395 $func .= " movq %rsp,%rax\n"; 396 $func .= "${decor}SEH_begin_$current_function->{name}:\n"; 397 my $narg = $current_function->{narg}; 398 $narg=6 if (!defined($narg)); 399 $func .= " movq %rcx,%rdi\n" if ($narg>0); 400 $func .= " movq %rdx,%rsi\n" if ($narg>1); 401 $func .= " movq %r8,%rdx\n" if ($narg>2); 402 $func .= " movq %r9,%rcx\n" if ($narg>3); 403 $func .= " movq 40(%rsp),%r8\n" if ($narg>4); 404 $func .= " movq 48(%rsp),%r9\n" if ($narg>5); 405 } 406 $func; 407 } elsif ($self->{value} ne "$current_function->{name}") { 408 # Make all labels in masm global. 409 $self->{value} .= ":" if ($masm); 410 $self->{value} . ":"; 411 } elsif ($win64 && $current_function->{abi} eq "svr4") { 412 my $func = "$current_function->{name}" . 413 ($nasm ? ":" : "\tPROC $current_function->{scope}") . 414 "\n"; 415 $func .= " mov QWORD$PTR\[8+rsp\],rdi\t;WIN64 prologue\n"; 416 $func .= " mov QWORD$PTR\[16+rsp\],rsi\n"; 417 $func .= " mov rax,rsp\n"; 418 $func .= "${decor}SEH_begin_$current_function->{name}:"; 419 $func .= ":" if ($masm); 420 $func .= "\n"; 421 my $narg = $current_function->{narg}; 422 $narg=6 if (!defined($narg)); 423 $func .= " mov rdi,rcx\n" if ($narg>0); 424 $func .= " mov rsi,rdx\n" if ($narg>1); 425 $func .= " mov rdx,r8\n" if ($narg>2); 426 $func .= " mov rcx,r9\n" if ($narg>3); 427 $func .= " mov r8,QWORD$PTR\[40+rsp\]\n" if ($narg>4); 428 $func .= " mov r9,QWORD$PTR\[48+rsp\]\n" if ($narg>5); 429 $func .= "\n"; 430 } else { 431 "$current_function->{name}". 432 ($nasm ? ":" : "\tPROC $current_function->{scope}"); 433 } 434 } 435 } 436 { package expr; # pick up expressions 437 sub re { 438 my ($class, $line, $opcode) = @_; 439 my $self = {}; 440 my $ret; 441 442 if ($$line =~ /(^[^,]+)/) { 443 bless $self,$class; 444 $self->{value} = $1; 445 $ret = $self; 446 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 447 448 $self->{value} =~ s/\@PLT// if (!$elf); 449 $self->{value} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; 450 $self->{value} =~ s/\.L/$decor/g; 451 $self->{opcode} = $opcode; 452 } 453 $ret; 454 } 455 sub out { 456 my $self = shift; 457 if ($nasm && $self->{opcode}->mnemonic()=~m/^j(?![re]cxz)/) { 458 "NEAR ".$self->{value}; 459 } else { 460 $self->{value}; 461 } 462 } 463 } 464 { package cfi_directive; 465 # CFI directives annotate instructions that are significant for 466 # stack unwinding procedure compliant with DWARF specification, 467 # see http://dwarfstd.org/. Besides naturally expected for this 468 # script platform-specific filtering function, this module adds 469 # three auxiliary synthetic directives not recognized by [GNU] 470 # assembler: 471 # 472 # - .cfi_push to annotate push instructions in prologue, which 473 # translates to .cfi_adjust_cfa_offset (if needed) and 474 # .cfi_offset; 475 # - .cfi_pop to annotate pop instructions in epilogue, which 476 # translates to .cfi_adjust_cfa_offset (if needed) and 477 # .cfi_restore; 478 # - [and most notably] .cfi_cfa_expression which encodes 479 # DW_CFA_def_cfa_expression and passes it to .cfi_escape as 480 # byte vector; 481 # 482 # CFA expressions were introduced in DWARF specification version 483 # 3 and describe how to deduce CFA, Canonical Frame Address. This 484 # becomes handy if your stack frame is variable and you can't 485 # spare register for [previous] frame pointer. Suggested directive 486 # syntax is made-up mix of DWARF operator suffixes [subset of] 487 # and references to registers with optional bias. Following example 488 # describes offloaded *original* stack pointer at specific offset 489 # from *current* stack pointer: 490 # 491 # .cfi_cfa_expression %rsp+40,deref,+8 492 # 493 # Final +8 has everything to do with the fact that CFA is defined 494 # as reference to top of caller's stack, and on x86_64 call to 495 # subroutine pushes 8-byte return address. In other words original 496 # stack pointer upon entry to a subroutine is 8 bytes off from CFA. 497 498 # Below constants are taken from "DWARF Expressions" section of the 499 # DWARF specification, section is numbered 7.7 in versions 3 and 4. 500 my %DW_OP_simple = ( # no-arg operators, mapped directly 501 deref => 0x06, dup => 0x12, 502 drop => 0x13, over => 0x14, 503 pick => 0x15, swap => 0x16, 504 rot => 0x17, xderef => 0x18, 505 506 abs => 0x19, and => 0x1a, 507 div => 0x1b, minus => 0x1c, 508 mod => 0x1d, mul => 0x1e, 509 neg => 0x1f, not => 0x20, 510 or => 0x21, plus => 0x22, 511 shl => 0x24, shr => 0x25, 512 shra => 0x26, xor => 0x27, 513 ); 514 515 my %DW_OP_complex = ( # used in specific subroutines 516 constu => 0x10, # uleb128 517 consts => 0x11, # sleb128 518 plus_uconst => 0x23, # uleb128 519 lit0 => 0x30, # add 0-31 to opcode 520 reg0 => 0x50, # add 0-31 to opcode 521 breg0 => 0x70, # add 0-31 to opcole, sleb128 522 regx => 0x90, # uleb28 523 fbreg => 0x91, # sleb128 524 bregx => 0x92, # uleb128, sleb128 525 piece => 0x93, # uleb128 526 ); 527 528 # Following constants are defined in x86_64 ABI supplement, for 529 # example avaiable at https://www.uclibc.org/docs/psABI-x86_64.pdf, 530 # see section 3.7 "Stack Unwind Algorithm". 531 my %DW_reg_idx = ( 532 "%rax"=>0, "%rdx"=>1, "%rcx"=>2, "%rbx"=>3, 533 "%rsi"=>4, "%rdi"=>5, "%rbp"=>6, "%rsp"=>7, 534 "%r8" =>8, "%r9" =>9, "%r10"=>10, "%r11"=>11, 535 "%r12"=>12, "%r13"=>13, "%r14"=>14, "%r15"=>15 536 ); 537 538 my ($cfa_reg, $cfa_rsp); 539 540 # [us]leb128 format is variable-length integer representation base 541 # 2^128, with most significant bit of each byte being 0 denoting 542 # *last* most significat digit. See "Variable Length Data" in the 543 # DWARF specification, numbered 7.6 at least in versions 3 and 4. 544 sub sleb128 { 545 use integer; # get right shift extend sign 546 547 my $val = shift; 548 my $sign = ($val < 0) ? -1 : 0; 549 my @ret = (); 550 551 while(1) { 552 push @ret, $val&0x7f; 553 554 # see if remaining bits are same and equal to most 555 # significant bit of the current digit, if so, it's 556 # last digit... 557 last if (($val>>6) == $sign); 558 559 @ret[-1] |= 0x80; 560 $val >>= 7; 561 } 562 563 return @ret; 564 } 565 sub uleb128 { 566 my $val = shift; 567 my @ret = (); 568 569 while(1) { 570 push @ret, $val&0x7f; 571 572 # see if it's last significant digit... 573 last if (($val >>= 7) == 0); 574 575 @ret[-1] |= 0x80; 576 } 577 578 return @ret; 579 } 580 sub const { 581 my $val = shift; 582 583 if ($val >= 0 && $val < 32) { 584 return ($DW_OP_complex{lit0}+$val); 585 } 586 return ($DW_OP_complex{consts}, sleb128($val)); 587 } 588 sub reg { 589 my $val = shift; 590 591 return if ($val !~ m/^(%r\w+)(?:([\+\-])((?:0x)?[0-9a-f]+))?/); 592 593 my $reg = $DW_reg_idx{$1}; 594 my $off = eval ("0 $2 $3"); 595 596 return (($DW_OP_complex{breg0} + $reg), sleb128($off)); 597 # Yes, we use DW_OP_bregX+0 to push register value and not 598 # DW_OP_regX, because latter would require even DW_OP_piece, 599 # which would be a waste under the circumstances. If you have 600 # to use DWP_OP_reg, use "regx:N"... 601 } 602 sub cfa_expression { 603 my $line = shift; 604 my @ret; 605 606 foreach my $token (split(/,\s*/,$line)) { 607 if ($token =~ /^%r/) { 608 push @ret,reg($token); 609 } elsif ($token =~ /((?:0x)?[0-9a-f]+)\((%r\w+)\)/) { 610 push @ret,reg("$2+$1"); 611 } elsif ($token =~ /(\w+):(\-?(?:0x)?[0-9a-f]+)(U?)/i) { 612 my $i = 1*eval($2); 613 push @ret,$DW_OP_complex{$1}, ($3 ? uleb128($i) : sleb128($i)); 614 } elsif (my $i = 1*eval($token) or $token eq "0") { 615 if ($token =~ /^\+/) { 616 push @ret,$DW_OP_complex{plus_uconst},uleb128($i); 617 } else { 618 push @ret,const($i); 619 } 620 } else { 621 push @ret,$DW_OP_simple{$token}; 622 } 623 } 624 625 # Finally we return DW_CFA_def_cfa_expression, 15, followed by 626 # length of the expression and of course the expression itself. 627 return (15,scalar(@ret),@ret); 628 } 629 sub re { 630 my ($class, $line) = @_; 631 my $self = {}; 632 my $ret; 633 634 if ($$line =~ s/^\s*\.cfi_(\w+)\s*//) { 635 bless $self,$class; 636 $ret = $self; 637 undef $self->{value}; 638 my $dir = $1; 639 640 SWITCH: for ($dir) { 641 # What is $cfa_rsp? Effectively it's difference between %rsp 642 # value and current CFA, Canonical Frame Address, which is 643 # why it starts with -8. Recall that CFA is top of caller's 644 # stack... 645 /startproc/ && do { ($cfa_reg, $cfa_rsp) = ("%rsp", -8); last; }; 646 /endproc/ && do { ($cfa_reg, $cfa_rsp) = ("%rsp", 0); last; }; 647 /def_cfa_register/ 648 && do { $cfa_reg = $$line; last; }; 649 /def_cfa_offset/ 650 && do { $cfa_rsp = -1*eval($$line) if ($cfa_reg eq "%rsp"); 651 last; 652 }; 653 /adjust_cfa_offset/ 654 && do { $cfa_rsp -= 1*eval($$line) if ($cfa_reg eq "%rsp"); 655 last; 656 }; 657 /def_cfa/ && do { if ($$line =~ /(%r\w+)\s*,\s*(.+)/) { 658 $cfa_reg = $1; 659 $cfa_rsp = -1*eval($2) if ($cfa_reg eq "%rsp"); 660 } 661 last; 662 }; 663 /push/ && do { $dir = undef; 664 $cfa_rsp -= 8; 665 if ($cfa_reg eq "%rsp") { 666 $self->{value} = ".cfi_adjust_cfa_offset\t8\n"; 667 } 668 $self->{value} .= ".cfi_offset\t$$line,$cfa_rsp"; 669 last; 670 }; 671 /pop/ && do { $dir = undef; 672 $cfa_rsp += 8; 673 if ($cfa_reg eq "%rsp") { 674 $self->{value} = ".cfi_adjust_cfa_offset\t-8\n"; 675 } 676 $self->{value} .= ".cfi_restore\t$$line"; 677 last; 678 }; 679 /cfa_expression/ 680 && do { $dir = undef; 681 $self->{value} = ".cfi_escape\t" . 682 join(",", map(sprintf("0x%02x", $_), 683 cfa_expression($$line))); 684 last; 685 }; 686 } 687 688 $self->{value} = ".cfi_$dir\t$$line" if ($dir); 689 690 $$line = ""; 691 } 692 693 return $ret; 694 } 695 sub out { 696 my $self = shift; 697 return ($elf ? $self->{value} : undef); 698 } 699 } 700 { package directive; # pick up directives, which start with . 701 sub re { 702 my ($class, $line) = @_; 703 my $self = {}; 704 my $ret; 705 my $dir; 706 707 # chain-call to cfi_directive 708 $ret = cfi_directive->re($line) and return $ret; 709 710 if ($$line =~ /^\s*(\.\w+)/) { 711 bless $self,$class; 712 $dir = $1; 713 $ret = $self; 714 undef $self->{value}; 715 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 716 717 SWITCH: for ($dir) { 718 /\.global|\.globl|\.extern/ 719 && do { $globals{$$line} = $prefix . $$line; 720 $$line = $globals{$$line} if ($prefix); 721 last; 722 }; 723 /\.type/ && do { my ($sym,$type,$narg) = split(',',$$line); 724 if ($type eq "\@function") { 725 undef $current_function; 726 $current_function->{name} = $sym; 727 $current_function->{abi} = "svr4"; 728 $current_function->{narg} = $narg; 729 $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE"; 730 } elsif ($type eq "\@abi-omnipotent") { 731 undef $current_function; 732 $current_function->{name} = $sym; 733 $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE"; 734 } 735 $$line =~ s/\@abi\-omnipotent/\@function/; 736 $$line =~ s/\@function.*/\@function/; 737 last; 738 }; 739 /\.asciz/ && do { if ($$line =~ /^"(.*)"$/) { 740 $dir = ".byte"; 741 $$line = join(",",unpack("C*",$1),0); 742 } 743 last; 744 }; 745 /\.rva|\.long|\.quad/ 746 && do { $$line =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; 747 $$line =~ s/\.L/$decor/g; 748 last; 749 }; 750 } 751 752 if ($gas) { 753 $self->{value} = $dir . "\t" . $$line; 754 755 if ($dir =~ /\.extern/) { 756 if ($flavour eq "elf") { 757 $self->{value} .= "\n.hidden $$line"; 758 } else { 759 $self->{value} = ""; 760 } 761 } elsif (!$elf && $dir =~ /\.type/) { 762 $self->{value} = ""; 763 $self->{value} = ".def\t" . ($globals{$1} or $1) . ";\t" . 764 (defined($globals{$1})?".scl 2;":".scl 3;") . 765 "\t.type 32;\t.endef" 766 if ($win64 && $$line =~ /([^,]+),\@function/); 767 } elsif (!$elf && $dir =~ /\.size/) { 768 $self->{value} = ""; 769 if (defined($current_function)) { 770 $self->{value} .= "${decor}SEH_end_$current_function->{name}:" 771 if ($win64 && $current_function->{abi} eq "svr4"); 772 undef $current_function; 773 } 774 } elsif (!$elf && $dir =~ /\.align/) { 775 $self->{value} = ".p2align\t" . (log($$line)/log(2)); 776 } elsif ($dir eq ".section") { 777 $current_segment=$$line; 778 if (!$elf && $current_segment eq ".init") { 779 if ($flavour eq "macosx") { $self->{value} = ".mod_init_func"; } 780 elsif ($flavour eq "mingw64") { $self->{value} = ".section\t.ctors"; } 781 } 782 } elsif ($dir =~ /\.(text|data)/) { 783 $current_segment=".$1"; 784 } elsif ($dir =~ /\.global|\.globl|\.extern/) { 785 if ($flavour eq "macosx") { 786 $self->{value} .= "\n.private_extern $$line"; 787 } else { 788 $self->{value} .= "\n.hidden $$line"; 789 } 790 } elsif ($dir =~ /\.hidden/) { 791 if ($flavour eq "macosx") { $self->{value} = ".private_extern\t$prefix$$line"; } 792 elsif ($flavour eq "mingw64") { $self->{value} = ""; } 793 } elsif ($dir =~ /\.comm/) { 794 $self->{value} = "$dir\t$prefix$$line"; 795 $self->{value} =~ s|,([0-9]+),([0-9]+)$|",$1,".log($2)/log(2)|e if ($flavour eq "macosx"); 796 } 797 $$line = ""; 798 return $self; 799 } 800 801 # non-gas case or nasm/masm 802 SWITCH: for ($dir) { 803 /\.text/ && do { my $v=undef; 804 if ($nasm) { 805 $v="section .text code align=64\n"; 806 } else { 807 $v="$current_segment\tENDS\n" if ($current_segment); 808 $current_segment = ".text\$"; 809 $v.="$current_segment\tSEGMENT "; 810 $v.=$masm>=$masmref ? "ALIGN(256)" : "PAGE"; 811 $v.=" 'CODE'"; 812 } 813 $self->{value} = $v; 814 last; 815 }; 816 /\.data/ && do { my $v=undef; 817 if ($nasm) { 818 $v="section .data data align=8\n"; 819 } else { 820 $v="$current_segment\tENDS\n" if ($current_segment); 821 $current_segment = "_DATA"; 822 $v.="$current_segment\tSEGMENT"; 823 } 824 $self->{value} = $v; 825 last; 826 }; 827 /\.section/ && do { my $v=undef; 828 $$line =~ s/([^,]*).*/$1/; 829 $$line = ".CRT\$XCU" if ($$line eq ".init"); 830 if ($nasm) { 831 $v="section $$line"; 832 if ($$line=~/\.([px])data/) { 833 $v.=" rdata align="; 834 $v.=$1 eq "p"? 4 : 8; 835 } elsif ($$line=~/\.CRT\$/i) { 836 $v.=" rdata align=8"; 837 } 838 } else { 839 $v="$current_segment\tENDS\n" if ($current_segment); 840 $v.="$$line\tSEGMENT"; 841 if ($$line=~/\.([px])data/) { 842 $v.=" READONLY"; 843 $v.=" ALIGN(".($1 eq "p" ? 4 : 8).")" if ($masm>=$masmref); 844 } elsif ($$line=~/\.CRT\$/i) { 845 $v.=" READONLY "; 846 $v.=$masm>=$masmref ? "ALIGN(8)" : "DWORD"; 847 } 848 } 849 $current_segment = $$line; 850 $self->{value} = $v; 851 last; 852 }; 853 /\.extern/ && do { $self->{value} = "EXTERN\t".$$line; 854 $self->{value} .= ":NEAR" if ($masm); 855 last; 856 }; 857 /\.globl|.global/ 858 && do { $self->{value} = $masm?"PUBLIC":"global"; 859 $self->{value} .= "\t".$$line; 860 last; 861 }; 862 /\.size/ && do { if (defined($current_function)) { 863 undef $self->{value}; 864 if ($current_function->{abi} eq "svr4") { 865 $self->{value}="${decor}SEH_end_$current_function->{name}:"; 866 $self->{value}.=":\n" if($masm); 867 } 868 $self->{value}.="$current_function->{name}\tENDP" if($masm && $current_function->{name}); 869 undef $current_function; 870 } 871 last; 872 }; 873 /\.align/ && do { my $max = ($masm && $masm>=$masmref) ? 256 : 4096; 874 $self->{value} = "ALIGN\t".($$line>$max?$max:$$line); 875 last; 876 }; 877 /\.(value|long|rva|quad)/ 878 && do { my $sz = substr($1,0,1); 879 my @arr = split(/,\s*/,$$line); 880 my $last = pop(@arr); 881 my $conv = sub { my $var=shift; 882 $var=~s/^(0b[0-1]+)/oct($1)/eig; 883 $var=~s/^0x([0-9a-f]+)/0$1h/ig if ($masm); 884 if ($sz eq "D" && ($current_segment=~/.[px]data/ || $dir eq ".rva")) 885 { $var=~s/([_a-z\$\@][_a-z0-9\$\@]*)/$nasm?"$1 wrt ..imagebase":"imagerel $1"/egi; } 886 $var; 887 }; 888 889 $sz =~ tr/bvlrq/BWDDQ/; 890 $self->{value} = "\tD$sz\t"; 891 for (@arr) { $self->{value} .= &$conv($_).","; } 892 $self->{value} .= &$conv($last); 893 last; 894 }; 895 /\.byte/ && do { my @str=split(/,\s*/,$$line); 896 map(s/(0b[0-1]+)/oct($1)/eig,@str); 897 map(s/0x([0-9a-f]+)/0$1h/ig,@str) if ($masm); 898 while ($#str>15) { 899 $self->{value}.="DB\t" 900 .join(",",@str[0..15])."\n"; 901 foreach (0..15) { shift @str; } 902 } 903 $self->{value}.="DB\t" 904 .join(",",@str) if (@str); 905 last; 906 }; 907 /\.comm/ && do { my @str=split(/,\s*/,$$line); 908 my $v=undef; 909 if ($nasm) { 910 $v.="common $prefix@str[0] @str[1]"; 911 } else { 912 $v="$current_segment\tENDS\n" if ($current_segment); 913 $current_segment = "_DATA"; 914 $v.="$current_segment\tSEGMENT\n"; 915 $v.="COMM @str[0]:DWORD:".@str[1]/4; 916 } 917 $self->{value} = $v; 918 last; 919 }; 920 } 921 $$line = ""; 922 } 923 924 $ret; 925 } 926 sub out { 927 my $self = shift; 928 $self->{value}; 929 } 930 } 931 932 # Upon initial x86_64 introduction SSE>2 extensions were not introduced 933 # yet. In order not to be bothered by tracing exact assembler versions, 934 # but at the same time to provide a bare security minimum of AES-NI, we 935 # hard-code some instructions. Extensions past AES-NI on the other hand 936 # are traced by examining assembler version in individual perlasm 937 # modules... 938 939 my %regrm = ( "%eax"=>0, "%ecx"=>1, "%edx"=>2, "%ebx"=>3, 940 "%esp"=>4, "%ebp"=>5, "%esi"=>6, "%edi"=>7 ); 941 942 sub rex { 943 my $opcode=shift; 944 my ($dst,$src,$rex)=@_; 945 946 $rex|=0x04 if($dst>=8); 947 $rex|=0x01 if($src>=8); 948 push @$opcode,($rex|0x40) if ($rex); 949 } 950 951 my $movq = sub { # elderly gas can't handle inter-register movq 952 my $arg = shift; 953 my @opcode=(0x66); 954 if ($arg =~ /%xmm([0-9]+),\s*%r(\w+)/) { 955 my ($src,$dst)=($1,$2); 956 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } 957 rex(\@opcode,$src,$dst,0x8); 958 push @opcode,0x0f,0x7e; 959 push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M 960 @opcode; 961 } elsif ($arg =~ /%r(\w+),\s*%xmm([0-9]+)/) { 962 my ($src,$dst)=($2,$1); 963 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } 964 rex(\@opcode,$src,$dst,0x8); 965 push @opcode,0x0f,0x6e; 966 push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M 967 @opcode; 968 } else { 969 (); 970 } 971 }; 972 973 my $pextrd = sub { 974 if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*(%\w+)/) { 975 my @opcode=(0x66); 976 my $imm=$1; 977 my $src=$2; 978 my $dst=$3; 979 if ($dst =~ /%r([0-9]+)d/) { $dst = $1; } 980 elsif ($dst =~ /%e/) { $dst = $regrm{$dst}; } 981 rex(\@opcode,$src,$dst); 982 push @opcode,0x0f,0x3a,0x16; 983 push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M 984 push @opcode,$imm; 985 @opcode; 986 } else { 987 (); 988 } 989 }; 990 991 my $pinsrd = sub { 992 if (shift =~ /\$([0-9]+),\s*(%\w+),\s*%xmm([0-9]+)/) { 993 my @opcode=(0x66); 994 my $imm=$1; 995 my $src=$2; 996 my $dst=$3; 997 if ($src =~ /%r([0-9]+)/) { $src = $1; } 998 elsif ($src =~ /%e/) { $src = $regrm{$src}; } 999 rex(\@opcode,$dst,$src); 1000 push @opcode,0x0f,0x3a,0x22; 1001 push @opcode,0xc0|(($dst&7)<<3)|($src&7); # ModR/M 1002 push @opcode,$imm; 1003 @opcode; 1004 } else { 1005 (); 1006 } 1007 }; 1008 1009 my $pshufb = sub { 1010 if (shift =~ /%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1011 my @opcode=(0x66); 1012 rex(\@opcode,$2,$1); 1013 push @opcode,0x0f,0x38,0x00; 1014 push @opcode,0xc0|($1&7)|(($2&7)<<3); # ModR/M 1015 @opcode; 1016 } else { 1017 (); 1018 } 1019 }; 1020 1021 my $palignr = sub { 1022 if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1023 my @opcode=(0x66); 1024 rex(\@opcode,$3,$2); 1025 push @opcode,0x0f,0x3a,0x0f; 1026 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M 1027 push @opcode,$1; 1028 @opcode; 1029 } else { 1030 (); 1031 } 1032 }; 1033 1034 my $pclmulqdq = sub { 1035 if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1036 my @opcode=(0x66); 1037 rex(\@opcode,$3,$2); 1038 push @opcode,0x0f,0x3a,0x44; 1039 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M 1040 my $c=$1; 1041 push @opcode,$c=~/^0/?oct($c):$c; 1042 @opcode; 1043 } else { 1044 (); 1045 } 1046 }; 1047 1048 my $rdrand = sub { 1049 if (shift =~ /%[er](\w+)/) { 1050 my @opcode=(); 1051 my $dst=$1; 1052 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } 1053 rex(\@opcode,0,$dst,8); 1054 push @opcode,0x0f,0xc7,0xf0|($dst&7); 1055 @opcode; 1056 } else { 1057 (); 1058 } 1059 }; 1060 1061 my $rdseed = sub { 1062 if (shift =~ /%[er](\w+)/) { 1063 my @opcode=(); 1064 my $dst=$1; 1065 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } 1066 rex(\@opcode,0,$dst,8); 1067 push @opcode,0x0f,0xc7,0xf8|($dst&7); 1068 @opcode; 1069 } else { 1070 (); 1071 } 1072 }; 1073 1074 # Not all AVX-capable assemblers recognize AMD XOP extension. Since we 1075 # are using only two instructions hand-code them in order to be excused 1076 # from chasing assembler versions... 1077 1078 sub rxb { 1079 my $opcode=shift; 1080 my ($dst,$src1,$src2,$rxb)=@_; 1081 1082 $rxb|=0x7<<5; 1083 $rxb&=~(0x04<<5) if($dst>=8); 1084 $rxb&=~(0x01<<5) if($src1>=8); 1085 $rxb&=~(0x02<<5) if($src2>=8); 1086 push @$opcode,$rxb; 1087 } 1088 1089 my $vprotd = sub { 1090 if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1091 my @opcode=(0x8f); 1092 rxb(\@opcode,$3,$2,-1,0x08); 1093 push @opcode,0x78,0xc2; 1094 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M 1095 my $c=$1; 1096 push @opcode,$c=~/^0/?oct($c):$c; 1097 @opcode; 1098 } else { 1099 (); 1100 } 1101 }; 1102 1103 my $vprotq = sub { 1104 if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1105 my @opcode=(0x8f); 1106 rxb(\@opcode,$3,$2,-1,0x08); 1107 push @opcode,0x78,0xc3; 1108 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M 1109 my $c=$1; 1110 push @opcode,$c=~/^0/?oct($c):$c; 1111 @opcode; 1112 } else { 1113 (); 1114 } 1115 }; 1116 1117 # Intel Control-flow Enforcement Technology extension. All functions and 1118 # indirect branch targets will have to start with this instruction... 1119 1120 my $endbranch = sub { 1121 (0xf3,0x0f,0x1e,0xfa); 1122 }; 1123 1124 ######################################################################## 1125 1126 if ($nasm) { 1127 print <<___; 1128 default rel 1129 %define XMMWORD 1130 %define YMMWORD 1131 %define ZMMWORD 1132 ___ 1133 } elsif ($masm) { 1134 print <<___; 1135 OPTION DOTNAME 1136 ___ 1137 } 1138 print STDOUT "#if defined(__x86_64__)\n" if ($gas); 1139 1140 while(defined(my $line=<>)) { 1141 1142 $line =~ s|\R$||; # Better chomp 1143 1144 $line =~ s|[#!].*$||; # get rid of asm-style comments... 1145 $line =~ s|/\*.*\*/||; # ... and C-style comments... 1146 $line =~ s|^\s+||; # ... and skip white spaces in beginning 1147 $line =~ s|\s+$||; # ... and at the end 1148 1149 if (my $label=label->re(\$line)) { print $label->out(); } 1150 1151 if (my $directive=directive->re(\$line)) { 1152 printf "%s",$directive->out(); 1153 } elsif (my $opcode=opcode->re(\$line)) { 1154 my $asm = eval("\$".$opcode->mnemonic()); 1155 1156 if ((ref($asm) eq 'CODE') && scalar(my @bytes=&$asm($line))) { 1157 print $gas?".byte\t":"DB\t",join(',',@bytes),"\n"; 1158 next; 1159 } 1160 1161 my @args; 1162 ARGUMENT: while (1) { 1163 my $arg; 1164 1165 ($arg=register->re(\$line, $opcode))|| 1166 ($arg=const->re(\$line)) || 1167 ($arg=ea->re(\$line, $opcode)) || 1168 ($arg=expr->re(\$line, $opcode)) || 1169 last ARGUMENT; 1170 1171 push @args,$arg; 1172 1173 last ARGUMENT if ($line !~ /^,/); 1174 1175 $line =~ s/^,\s*//; 1176 } # ARGUMENT: 1177 1178 if ($#args>=0) { 1179 my $insn; 1180 my $sz=$opcode->size(); 1181 1182 if ($gas) { 1183 $insn = $opcode->out($#args>=1?$args[$#args]->size():$sz); 1184 @args = map($_->out($sz),@args); 1185 printf "\t%s\t%s",$insn,join(",",@args); 1186 } else { 1187 $insn = $opcode->out(); 1188 foreach (@args) { 1189 my $arg = $_->out(); 1190 # $insn.=$sz compensates for movq, pinsrw, ... 1191 if ($arg =~ /^xmm[0-9]+$/) { $insn.=$sz; $sz="x" if(!$sz); last; } 1192 if ($arg =~ /^ymm[0-9]+$/) { $insn.=$sz; $sz="y" if(!$sz); last; } 1193 if ($arg =~ /^zmm[0-9]+$/) { $insn.=$sz; $sz="z" if(!$sz); last; } 1194 if ($arg =~ /^mm[0-9]+$/) { $insn.=$sz; $sz="q" if(!$sz); last; } 1195 } 1196 @args = reverse(@args); 1197 undef $sz if ($nasm && $opcode->mnemonic() eq "lea"); 1198 1199 if ($insn eq "movq" && $#args == 1 && $args[0]->out($sz) eq "xmm0" && $args[1]->out($sz) eq "rax") { 1200 # I have no clue why MASM can't parse this instruction. 1201 printf "DB 66h, 48h, 0fh, 6eh, 0c0h"; 1202 } else { 1203 printf "\t%s\t%s",$insn,join(",",map($_->out($sz),@args)); 1204 } 1205 } 1206 } else { 1207 printf "\t%s",$opcode->out(); 1208 } 1209 } 1210 1211 print $line,"\n"; 1212 } 1213 1214 print "\n$current_segment\tENDS\n" if ($current_segment && $masm); 1215 print "END\n" if ($masm); 1216 print "#endif\n" if ($gas); 1217 1218 1219 close STDOUT; 1220 1221 ################################################# 1223 # Cross-reference x86_64 ABI "card" 1224 # 1225 # Unix Win64 1226 # %rax * * 1227 # %rbx - - 1228 # %rcx #4 #1 1229 # %rdx #3 #2 1230 # %rsi #2 - 1231 # %rdi #1 - 1232 # %rbp - - 1233 # %rsp - - 1234 # %r8 #5 #3 1235 # %r9 #6 #4 1236 # %r10 * * 1237 # %r11 * * 1238 # %r12 - - 1239 # %r13 - - 1240 # %r14 - - 1241 # %r15 - - 1242 # 1243 # (*) volatile register 1244 # (-) preserved by callee 1245 # (#) Nth argument, volatile 1246 # 1247 # In Unix terms top of stack is argument transfer area for arguments 1248 # which could not be accommodated in registers. Or in other words 7th 1249 # [integer] argument resides at 8(%rsp) upon function entry point. 1250 # 128 bytes above %rsp constitute a "red zone" which is not touched 1251 # by signal handlers and can be used as temporal storage without 1252 # allocating a frame. 1253 # 1254 # In Win64 terms N*8 bytes on top of stack is argument transfer area, 1255 # which belongs to/can be overwritten by callee. N is the number of 1256 # arguments passed to callee, *but* not less than 4! This means that 1257 # upon function entry point 5th argument resides at 40(%rsp), as well 1258 # as that 32 bytes from 8(%rsp) can always be used as temporal 1259 # storage [without allocating a frame]. One can actually argue that 1260 # one can assume a "red zone" above stack pointer under Win64 as well. 1261 # Point is that at apparently no occasion Windows kernel would alter 1262 # the area above user stack pointer in true asynchronous manner... 1263 # 1264 # All the above means that if assembler programmer adheres to Unix 1265 # register and stack layout, but disregards the "red zone" existence, 1266 # it's possible to use following prologue and epilogue to "gear" from 1267 # Unix to Win64 ABI in leaf functions with not more than 6 arguments. 1268 # 1269 # omnipotent_function: 1270 # ifdef WIN64 1271 # movq %rdi,8(%rsp) 1272 # movq %rsi,16(%rsp) 1273 # movq %rcx,%rdi ; if 1st argument is actually present 1274 # movq %rdx,%rsi ; if 2nd argument is actually ... 1275 # movq %r8,%rdx ; if 3rd argument is ... 1276 # movq %r9,%rcx ; if 4th argument ... 1277 # movq 40(%rsp),%r8 ; if 5th ... 1278 # movq 48(%rsp),%r9 ; if 6th ... 1279 # endif 1280 # ... 1281 # ifdef WIN64 1282 # movq 8(%rsp),%rdi 1283 # movq 16(%rsp),%rsi 1284 # endif 1285 # ret 1286 # 1287 ################################################# 1289 # Win64 SEH, Structured Exception Handling. 1290 # 1291 # Unlike on Unix systems(*) lack of Win64 stack unwinding information 1292 # has undesired side-effect at run-time: if an exception is raised in 1293 # assembler subroutine such as those in question (basically we're 1294 # referring to segmentation violations caused by malformed input 1295 # parameters), the application is briskly terminated without invoking 1296 # any exception handlers, most notably without generating memory dump 1297 # or any user notification whatsoever. This poses a problem. It's 1298 # possible to address it by registering custom language-specific 1299 # handler that would restore processor context to the state at 1300 # subroutine entry point and return "exception is not handled, keep 1301 # unwinding" code. Writing such handler can be a challenge... But it's 1302 # doable, though requires certain coding convention. Consider following 1303 # snippet: 1304 # 1305 # .type function,@function 1306 # function: 1307 # movq %rsp,%rax # copy rsp to volatile register 1308 # pushq %r15 # save non-volatile registers 1309 # pushq %rbx 1310 # pushq %rbp 1311 # movq %rsp,%r11 1312 # subq %rdi,%r11 # prepare [variable] stack frame 1313 # andq $-64,%r11 1314 # movq %rax,0(%r11) # check for exceptions 1315 # movq %r11,%rsp # allocate [variable] stack frame 1316 # movq %rax,0(%rsp) # save original rsp value 1317 # magic_point: 1318 # ... 1319 # movq 0(%rsp),%rcx # pull original rsp value 1320 # movq -24(%rcx),%rbp # restore non-volatile registers 1321 # movq -16(%rcx),%rbx 1322 # movq -8(%rcx),%r15 1323 # movq %rcx,%rsp # restore original rsp 1324 # magic_epilogue: 1325 # ret 1326 # .size function,.-function 1327 # 1328 # The key is that up to magic_point copy of original rsp value remains 1329 # in chosen volatile register and no non-volatile register, except for 1330 # rsp, is modified. While past magic_point rsp remains constant till 1331 # the very end of the function. In this case custom language-specific 1332 # exception handler would look like this: 1333 # 1334 # EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame, 1335 # CONTEXT *context,DISPATCHER_CONTEXT *disp) 1336 # { ULONG64 *rsp = (ULONG64 *)context->Rax; 1337 # ULONG64 rip = context->Rip; 1338 # 1339 # if (rip >= magic_point) 1340 # { rsp = (ULONG64 *)context->Rsp; 1341 # if (rip < magic_epilogue) 1342 # { rsp = (ULONG64 *)rsp[0]; 1343 # context->Rbp = rsp[-3]; 1344 # context->Rbx = rsp[-2]; 1345 # context->R15 = rsp[-1]; 1346 # } 1347 # } 1348 # context->Rsp = (ULONG64)rsp; 1349 # context->Rdi = rsp[1]; 1350 # context->Rsi = rsp[2]; 1351 # 1352 # memcpy (disp->ContextRecord,context,sizeof(CONTEXT)); 1353 # RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase, 1354 # dips->ControlPc,disp->FunctionEntry,disp->ContextRecord, 1355 # &disp->HandlerData,&disp->EstablisherFrame,NULL); 1356 # return ExceptionContinueSearch; 1357 # } 1358 # 1359 # It's appropriate to implement this handler in assembler, directly in 1360 # function's module. In order to do that one has to know members' 1361 # offsets in CONTEXT and DISPATCHER_CONTEXT structures and some constant 1362 # values. Here they are: 1363 # 1364 # CONTEXT.Rax 120 1365 # CONTEXT.Rcx 128 1366 # CONTEXT.Rdx 136 1367 # CONTEXT.Rbx 144 1368 # CONTEXT.Rsp 152 1369 # CONTEXT.Rbp 160 1370 # CONTEXT.Rsi 168 1371 # CONTEXT.Rdi 176 1372 # CONTEXT.R8 184 1373 # CONTEXT.R9 192 1374 # CONTEXT.R10 200 1375 # CONTEXT.R11 208 1376 # CONTEXT.R12 216 1377 # CONTEXT.R13 224 1378 # CONTEXT.R14 232 1379 # CONTEXT.R15 240 1380 # CONTEXT.Rip 248 1381 # CONTEXT.Xmm6 512 1382 # sizeof(CONTEXT) 1232 1383 # DISPATCHER_CONTEXT.ControlPc 0 1384 # DISPATCHER_CONTEXT.ImageBase 8 1385 # DISPATCHER_CONTEXT.FunctionEntry 16 1386 # DISPATCHER_CONTEXT.EstablisherFrame 24 1387 # DISPATCHER_CONTEXT.TargetIp 32 1388 # DISPATCHER_CONTEXT.ContextRecord 40 1389 # DISPATCHER_CONTEXT.LanguageHandler 48 1390 # DISPATCHER_CONTEXT.HandlerData 56 1391 # UNW_FLAG_NHANDLER 0 1392 # ExceptionContinueSearch 1 1393 # 1394 # In order to tie the handler to the function one has to compose 1395 # couple of structures: one for .xdata segment and one for .pdata. 1396 # 1397 # UNWIND_INFO structure for .xdata segment would be 1398 # 1399 # function_unwind_info: 1400 # .byte 9,0,0,0 1401 # .rva handler 1402 # 1403 # This structure designates exception handler for a function with 1404 # zero-length prologue, no stack frame or frame register. 1405 # 1406 # To facilitate composing of .pdata structures, auto-generated "gear" 1407 # prologue copies rsp value to rax and denotes next instruction with 1408 # .LSEH_begin_{function_name} label. This essentially defines the SEH 1409 # styling rule mentioned in the beginning. Position of this label is 1410 # chosen in such manner that possible exceptions raised in the "gear" 1411 # prologue would be accounted to caller and unwound from latter's frame. 1412 # End of function is marked with respective .LSEH_end_{function_name} 1413 # label. To summarize, .pdata segment would contain 1414 # 1415 # .rva .LSEH_begin_function 1416 # .rva .LSEH_end_function 1417 # .rva function_unwind_info 1418 # 1419 # Reference to function_unwind_info from .xdata segment is the anchor. 1420 # In case you wonder why references are 32-bit .rvas and not 64-bit 1421 # .quads. References put into these two segments are required to be 1422 # *relative* to the base address of the current binary module, a.k.a. 1423 # image base. No Win64 module, be it .exe or .dll, can be larger than 1424 # 2GB and thus such relative references can be and are accommodated in 1425 # 32 bits. 1426 # 1427 # Having reviewed the example function code, one can argue that "movq 1428 # %rsp,%rax" above is redundant. It is not! Keep in mind that on Unix 1429 # rax would contain an undefined value. If this "offends" you, use 1430 # another register and refrain from modifying rax till magic_point is 1431 # reached, i.e. as if it was a non-volatile register. If more registers 1432 # are required prior [variable] frame setup is completed, note that 1433 # nobody says that you can have only one "magic point." You can 1434 # "liberate" non-volatile registers by denoting last stack off-load 1435 # instruction and reflecting it in finer grade unwind logic in handler. 1436 # After all, isn't it why it's called *language-specific* handler... 1437 # 1438 # SE handlers are also involved in unwinding stack when executable is 1439 # profiled or debugged. Profiling implies additional limitations that 1440 # are too subtle to discuss here. For now it's sufficient to say that 1441 # in order to simplify handlers one should either a) offload original 1442 # %rsp to stack (like discussed above); or b) if you have a register to 1443 # spare for frame pointer, choose volatile one. 1444 # 1445 # (*) Note that we're talking about run-time, not debug-time. Lack of 1446 # unwind information makes debugging hard on both Windows and 1447 # Unix. "Unlike" referes to the fact that on Unix signal handler 1448 # will always be invoked, core dumped and appropriate exit code 1449 # returned to parent (for user notification). 1450
