1#! /usr/bin/env perl 2# Copyright 2005-2020 The OpenSSL Project Authors. All Rights Reserved. 3# 4# Licensed under the Apache License 2.0 (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 63 64use strict; 65 66my $flavour = shift; 67my $output = shift; 68if ($flavour =~ /\./) { $output = $flavour; undef $flavour; } 69 70open STDOUT,">$output" || die "can't open $output: $!" 71 if (defined($output)); 72 73my $gas=1; $gas=0 if ($output =~ /\.asm$/); 74my $elf=1; $elf=0 if (!$gas); 75my $win64=0; 76my $prefix=""; 77my $decor=".L"; 78 79my $masmref=8 + 50727*2**-32; # 8.00.50727 shipped with VS2005 80my $masm=0; 81my $PTR=" PTR"; 82 83my $nasmref=2.03; 84my $nasm=0; 85 86# GNU as indicator, as opposed to $gas, which indicates acceptable 87# syntax 88my $gnuas=0; 89 90if ($flavour eq "mingw64") { $gas=1; $elf=0; $win64=1; 91 $prefix=`echo __USER_LABEL_PREFIX__ | $ENV{CC} -E -P -`; 92 $prefix =~ s|\R$||; # Better chomp 93 } 94elsif ($flavour eq "macosx") { $gas=1; $elf=0; $prefix="_"; $decor="L\$"; } 95elsif ($flavour eq "masm") { $gas=0; $elf=0; $masm=$masmref; $win64=1; $decor="\$L\$"; } 96elsif ($flavour eq "nasm") { $gas=0; $elf=0; $nasm=$nasmref; $win64=1; $decor="\$L\$"; $PTR=""; } 97elsif (!$gas) 98{ if ($ENV{ASM} =~ m/nasm/ && `nasm -v` =~ m/version ([0-9]+)\.([0-9]+)/i) 99 { $nasm = $1 + $2*0.01; $PTR=""; } 100 elsif (`ml64 2>&1` =~ m/Version ([0-9]+)\.([0-9]+)(\.([0-9]+))?/) 101 { $masm = $1 + $2*2**-16 + $4*2**-32; } 102 die "no assembler found on %PATH%" if (!($nasm || $masm)); 103 $win64=1; 104 $elf=0; 105 $decor="\$L\$"; 106} 107# Find out if we're using GNU as 108elsif (`$ENV{CC} -Wa,-v -c -o /dev/null -x assembler /dev/null 2>&1` 109 =~ /GNU assembler version ([2-9]\.[0-9]+)/) 110{ 111 $gnuas=1; 112} 113elsif (`$ENV{CC} --version 2>/dev/null` 114 =~ /(clang .*|Intel.*oneAPI .*)/) 115{ 116 $gnuas=1; 117} 118elsif (`$ENV{CC} -V 2>/dev/null` 119 =~ /nvc .*/) 120{ 121 $gnuas=1; 122} 123 124my $cet_property; 125if ($flavour =~ /elf/) { 126 # Always generate .note.gnu.property section for ELF outputs to 127 # mark Intel CET support since all input files must be marked 128 # with Intel CET support in order for linker to mark output with 129 # Intel CET support. 130 my $p2align=3; $p2align=2 if ($flavour eq "elf32"); 131 my $section='.note.gnu.property, #alloc'; 132 $section='".note.gnu.property", "a"' if $gnuas; 133 $cet_property = <<_____; 134 .section $section 135 .p2align $p2align 136 .long 1f - 0f 137 .long 4f - 1f 138 .long 5 1390: 140 # "GNU" encoded with .byte, since .asciz isn't supported 141 # on Solaris. 142 .byte 0x47 143 .byte 0x4e 144 .byte 0x55 145 .byte 0 1461: 147 .p2align $p2align 148 .long 0xc0000002 149 .long 3f - 2f 1502: 151 .long 3 1523: 153 .p2align $p2align 1544: 155_____ 156} 157 158my $current_segment; 159my $current_function; 160my %globals; 161 162{ package opcode; # pick up opcodes 163 sub re { 164 my ($class, $line) = @_; 165 my $self = {}; 166 my $ret; 167 168 if ($$line =~ /^([a-z][a-z0-9]*)/i) { 169 bless $self,$class; 170 $self->{op} = $1; 171 $ret = $self; 172 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 173 174 undef $self->{sz}; 175 if ($self->{op} =~ /^(movz)x?([bw]).*/) { # movz is pain... 176 $self->{op} = $1; 177 $self->{sz} = $2; 178 } elsif ($self->{op} =~ /call|jmp/) { 179 $self->{sz} = ""; 180 } elsif ($self->{op} =~ /^p/ && $' !~ /^(ush|op|insrw)/) { # SSEn 181 $self->{sz} = ""; 182 } elsif ($self->{op} =~ /^[vk]/) { # VEX or k* such as kmov 183 $self->{sz} = ""; 184 } elsif ($self->{op} =~ /mov[dq]/ && $$line =~ /%xmm/) { 185 $self->{sz} = ""; 186 } elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) { 187 $self->{op} = $1; 188 $self->{sz} = $2; 189 } 190 } 191 $ret; 192 } 193 sub size { 194 my ($self, $sz) = @_; 195 $self->{sz} = $sz if (defined($sz) && !defined($self->{sz})); 196 $self->{sz}; 197 } 198 sub out { 199 my $self = shift; 200 if ($gas) { 201 if ($self->{op} eq "movz") { # movz is pain... 202 sprintf "%s%s%s",$self->{op},$self->{sz},shift; 203 } elsif ($self->{op} =~ /^set/) { 204 "$self->{op}"; 205 } elsif ($self->{op} eq "ret") { 206 my $epilogue = ""; 207 if ($win64 && $current_function->{abi} eq "svr4") { 208 $epilogue = "movq 8(%rsp),%rdi\n\t" . 209 "movq 16(%rsp),%rsi\n\t"; 210 } 211 $epilogue . ".byte 0xf3,0xc3"; 212 } elsif ($self->{op} eq "call" && !$elf && $current_segment eq ".init") { 213 ".p2align\t3\n\t.quad"; 214 } else { 215 "$self->{op}$self->{sz}"; 216 } 217 } else { 218 $self->{op} =~ s/^movz/movzx/; 219 if ($self->{op} eq "ret") { 220 $self->{op} = ""; 221 if ($win64 && $current_function->{abi} eq "svr4") { 222 $self->{op} = "mov rdi,QWORD$PTR\[8+rsp\]\t;WIN64 epilogue\n\t". 223 "mov rsi,QWORD$PTR\[16+rsp\]\n\t"; 224 } 225 $self->{op} .= "DB\t0F3h,0C3h\t\t;repret"; 226 } elsif ($self->{op} =~ /^(pop|push)f/) { 227 $self->{op} .= $self->{sz}; 228 } elsif ($self->{op} eq "call" && $current_segment eq ".CRT\$XCU") { 229 $self->{op} = "\tDQ"; 230 } 231 $self->{op}; 232 } 233 } 234 sub mnemonic { 235 my ($self, $op) = @_; 236 $self->{op}=$op if (defined($op)); 237 $self->{op}; 238 } 239} 240{ package const; # pick up constants, which start with $ 241 sub re { 242 my ($class, $line) = @_; 243 my $self = {}; 244 my $ret; 245 246 if ($$line =~ /^\$([^,]+)/) { 247 bless $self, $class; 248 $self->{value} = $1; 249 $ret = $self; 250 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 251 } 252 $ret; 253 } 254 sub out { 255 my $self = shift; 256 257 $self->{value} =~ s/\b(0b[0-1]+)/oct($1)/eig; 258 if ($gas) { 259 # Solaris /usr/ccs/bin/as can't handle multiplications 260 # in $self->{value} 261 my $value = $self->{value}; 262 no warnings; # oct might complain about overflow, ignore here... 263 $value =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi; 264 if ($value =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg) { 265 $self->{value} = $value; 266 } 267 sprintf "\$%s",$self->{value}; 268 } else { 269 my $value = $self->{value}; 270 $value =~ s/0x([0-9a-f]+)/0$1h/ig if ($masm); 271 sprintf "%s",$value; 272 } 273 } 274} 275{ package ea; # pick up effective addresses: expr(%reg,%reg,scale) 276 277 my %szmap = ( b=>"BYTE$PTR", w=>"WORD$PTR", 278 l=>"DWORD$PTR", d=>"DWORD$PTR", 279 q=>"QWORD$PTR", o=>"OWORD$PTR", 280 x=>"XMMWORD$PTR", y=>"YMMWORD$PTR", 281 z=>"ZMMWORD$PTR" ) if (!$gas); 282 283 sub re { 284 my ($class, $line, $opcode) = @_; 285 my $self = {}; 286 my $ret; 287 288 # optional * ----vvv--- appears in indirect jmp/call 289 if ($$line =~ /^(\*?)([^\(,]*)\(([%\w,]+)\)((?:{[^}]+})*)/) { 290 bless $self, $class; 291 $self->{asterisk} = $1; 292 $self->{label} = $2; 293 ($self->{base},$self->{index},$self->{scale})=split(/,/,$3); 294 $self->{scale} = 1 if (!defined($self->{scale})); 295 $self->{opmask} = $4; 296 $ret = $self; 297 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 298 299 if ($win64 && $self->{label} =~ s/\@GOTPCREL//) { 300 die if ($opcode->mnemonic() ne "mov"); 301 $opcode->mnemonic("lea"); 302 } 303 $self->{base} =~ s/^%//; 304 $self->{index} =~ s/^%// if (defined($self->{index})); 305 $self->{opcode} = $opcode; 306 } 307 $ret; 308 } 309 sub size {} 310 sub out { 311 my ($self, $sz) = @_; 312 313 $self->{label} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; 314 $self->{label} =~ s/\.L/$decor/g; 315 316 # Silently convert all EAs to 64-bit. This is required for 317 # elder GNU assembler and results in more compact code, 318 # *but* most importantly AES module depends on this feature! 319 $self->{index} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; 320 $self->{base} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; 321 322 # Solaris /usr/ccs/bin/as can't handle multiplications 323 # in $self->{label}... 324 use integer; 325 $self->{label} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi; 326 $self->{label} =~ s/\b([0-9]+\s*[\*\/\%]\s*[0-9]+)\b/eval($1)/eg; 327 328 # Some assemblers insist on signed presentation of 32-bit 329 # offsets, but sign extension is a tricky business in perl... 330 if ((1<<31)<<1) { 331 $self->{label} =~ s/\b([0-9]+)\b/$1<<32>>32/eg; 332 } else { 333 $self->{label} =~ s/\b([0-9]+)\b/$1>>0/eg; 334 } 335 336 # if base register is %rbp or %r13, see if it's possible to 337 # flip base and index registers [for better performance] 338 if (!$self->{label} && $self->{index} && $self->{scale}==1 && 339 $self->{base} =~ /(rbp|r13)/) { 340 $self->{base} = $self->{index}; $self->{index} = $1; 341 } 342 343 if ($gas) { 344 $self->{label} =~ s/^___imp_/__imp__/ if ($flavour eq "mingw64"); 345 346 if (defined($self->{index})) { 347 sprintf "%s%s(%s,%%%s,%d)%s", 348 $self->{asterisk},$self->{label}, 349 $self->{base}?"%$self->{base}":"", 350 $self->{index},$self->{scale}, 351 $self->{opmask}; 352 } else { 353 sprintf "%s%s(%%%s)%s", $self->{asterisk},$self->{label}, 354 $self->{base},$self->{opmask}; 355 } 356 } else { 357 $self->{label} =~ s/\./\$/g; 358 $self->{label} =~ s/(?<![\w\$\.])0x([0-9a-f]+)/0$1h/ig; 359 $self->{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/); 360 361 my $mnemonic = $self->{opcode}->mnemonic(); 362 ($self->{asterisk}) && ($sz="q") || 363 ($mnemonic =~ /^v?mov([qd])$/) && ($sz=$1) || 364 ($mnemonic =~ /^v?pinsr([qdwb])$/) && ($sz=$1) || 365 ($mnemonic =~ /^vpbroadcast([qdwb])$/) && ($sz=$1) || 366 ($mnemonic =~ /^v(?!perm)[a-z]+[fi]128$/) && ($sz="x"); 367 368 $self->{opmask} =~ s/%(k[0-7])/$1/; 369 370 if (defined($self->{index})) { 371 sprintf "%s[%s%s*%d%s]%s",$szmap{$sz}, 372 $self->{label}?"$self->{label}+":"", 373 $self->{index},$self->{scale}, 374 $self->{base}?"+$self->{base}":"", 375 $self->{opmask}; 376 } elsif ($self->{base} eq "rip") { 377 sprintf "%s[%s]",$szmap{$sz},$self->{label}; 378 } else { 379 sprintf "%s[%s%s]%s", $szmap{$sz}, 380 $self->{label}?"$self->{label}+":"", 381 $self->{base},$self->{opmask}; 382 } 383 } 384 } 385} 386{ package register; # pick up registers, which start with %. 387 sub re { 388 my ($class, $line, $opcode) = @_; 389 my $self = {}; 390 my $ret; 391 392 # optional * ----vvv--- appears in indirect jmp/call 393 if ($$line =~ /^(\*?)%(\w+)((?:{[^}]+})*)/) { 394 bless $self,$class; 395 $self->{asterisk} = $1; 396 $self->{value} = $2; 397 $self->{opmask} = $3; 398 $opcode->size($self->size()); 399 $ret = $self; 400 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 401 } 402 $ret; 403 } 404 sub size { 405 my $self = shift; 406 my $ret; 407 408 if ($self->{value} =~ /^r[\d]+b$/i) { $ret="b"; } 409 elsif ($self->{value} =~ /^r[\d]+w$/i) { $ret="w"; } 410 elsif ($self->{value} =~ /^r[\d]+d$/i) { $ret="l"; } 411 elsif ($self->{value} =~ /^r[\w]+$/i) { $ret="q"; } 412 elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; } 413 elsif ($self->{value} =~ /^[\w]{2}l$/i) { $ret="b"; } 414 elsif ($self->{value} =~ /^[\w]{2}$/i) { $ret="w"; } 415 elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; } 416 417 $ret; 418 } 419 sub out { 420 my $self = shift; 421 if ($gas) { sprintf "%s%%%s%s", $self->{asterisk}, 422 $self->{value}, 423 $self->{opmask}; } 424 else { $self->{opmask} =~ s/%(k[0-7])/$1/; 425 $self->{value}.$self->{opmask}; } 426 } 427} 428{ package label; # pick up labels, which end with : 429 sub re { 430 my ($class, $line) = @_; 431 my $self = {}; 432 my $ret; 433 434 if ($$line =~ /(^[\.\w]+)\:/) { 435 bless $self,$class; 436 $self->{value} = $1; 437 $ret = $self; 438 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 439 440 $self->{value} =~ s/^\.L/$decor/; 441 } 442 $ret; 443 } 444 sub out { 445 my $self = shift; 446 447 if ($gas) { 448 my $func = ($globals{$self->{value}} or $self->{value}) . ":"; 449 if ($win64 && $current_function->{name} eq $self->{value} 450 && $current_function->{abi} eq "svr4") { 451 $func .= "\n"; 452 $func .= " movq %rdi,8(%rsp)\n"; 453 $func .= " movq %rsi,16(%rsp)\n"; 454 $func .= " movq %rsp,%rax\n"; 455 $func .= "${decor}SEH_begin_$current_function->{name}:\n"; 456 my $narg = $current_function->{narg}; 457 $narg=6 if (!defined($narg)); 458 $func .= " movq %rcx,%rdi\n" if ($narg>0); 459 $func .= " movq %rdx,%rsi\n" if ($narg>1); 460 $func .= " movq %r8,%rdx\n" if ($narg>2); 461 $func .= " movq %r9,%rcx\n" if ($narg>3); 462 $func .= " movq 40(%rsp),%r8\n" if ($narg>4); 463 $func .= " movq 48(%rsp),%r9\n" if ($narg>5); 464 } 465 $func; 466 } elsif ($self->{value} ne "$current_function->{name}") { 467 # Make all labels in masm global. 468 $self->{value} .= ":" if ($masm); 469 $self->{value} . ":"; 470 } elsif ($win64 && $current_function->{abi} eq "svr4") { 471 my $func = "$current_function->{name}" . 472 ($nasm ? ":" : "\tPROC $current_function->{scope}") . 473 "\n"; 474 $func .= " mov QWORD$PTR\[8+rsp\],rdi\t;WIN64 prologue\n"; 475 $func .= " mov QWORD$PTR\[16+rsp\],rsi\n"; 476 $func .= " mov rax,rsp\n"; 477 $func .= "${decor}SEH_begin_$current_function->{name}:"; 478 $func .= ":" if ($masm); 479 $func .= "\n"; 480 my $narg = $current_function->{narg}; 481 $narg=6 if (!defined($narg)); 482 $func .= " mov rdi,rcx\n" if ($narg>0); 483 $func .= " mov rsi,rdx\n" if ($narg>1); 484 $func .= " mov rdx,r8\n" if ($narg>2); 485 $func .= " mov rcx,r9\n" if ($narg>3); 486 $func .= " mov r8,QWORD$PTR\[40+rsp\]\n" if ($narg>4); 487 $func .= " mov r9,QWORD$PTR\[48+rsp\]\n" if ($narg>5); 488 $func .= "\n"; 489 } else { 490 "$current_function->{name}". 491 ($nasm ? ":" : "\tPROC $current_function->{scope}"); 492 } 493 } 494} 495{ package expr; # pick up expressions 496 sub re { 497 my ($class, $line, $opcode) = @_; 498 my $self = {}; 499 my $ret; 500 501 if ($$line =~ /(^[^,]+)/) { 502 bless $self,$class; 503 $self->{value} = $1; 504 $ret = $self; 505 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 506 507 $self->{value} =~ s/\@PLT// if (!$elf); 508 $self->{value} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; 509 $self->{value} =~ s/\.L/$decor/g; 510 $self->{opcode} = $opcode; 511 } 512 $ret; 513 } 514 sub out { 515 my $self = shift; 516 if ($nasm && $self->{opcode}->mnemonic()=~m/^j(?![re]cxz)/) { 517 "NEAR ".$self->{value}; 518 } else { 519 $self->{value}; 520 } 521 } 522} 523{ package cfi_directive; 524 # CFI directives annotate instructions that are significant for 525 # stack unwinding procedure compliant with DWARF specification, 526 # see http://dwarfstd.org/. Besides naturally expected for this 527 # script platform-specific filtering function, this module adds 528 # three auxiliary synthetic directives not recognized by [GNU] 529 # assembler: 530 # 531 # - .cfi_push to annotate push instructions in prologue, which 532 # translates to .cfi_adjust_cfa_offset (if needed) and 533 # .cfi_offset; 534 # - .cfi_pop to annotate pop instructions in epilogue, which 535 # translates to .cfi_adjust_cfa_offset (if needed) and 536 # .cfi_restore; 537 # - [and most notably] .cfi_cfa_expression which encodes 538 # DW_CFA_def_cfa_expression and passes it to .cfi_escape as 539 # byte vector; 540 # 541 # CFA expressions were introduced in DWARF specification version 542 # 3 and describe how to deduce CFA, Canonical Frame Address. This 543 # becomes handy if your stack frame is variable and you can't 544 # spare register for [previous] frame pointer. Suggested directive 545 # syntax is made-up mix of DWARF operator suffixes [subset of] 546 # and references to registers with optional bias. Following example 547 # describes offloaded *original* stack pointer at specific offset 548 # from *current* stack pointer: 549 # 550 # .cfi_cfa_expression %rsp+40,deref,+8 551 # 552 # Final +8 has everything to do with the fact that CFA is defined 553 # as reference to top of caller's stack, and on x86_64 call to 554 # subroutine pushes 8-byte return address. In other words original 555 # stack pointer upon entry to a subroutine is 8 bytes off from CFA. 556 557 # Below constants are taken from "DWARF Expressions" section of the 558 # DWARF specification, section is numbered 7.7 in versions 3 and 4. 559 my %DW_OP_simple = ( # no-arg operators, mapped directly 560 deref => 0x06, dup => 0x12, 561 drop => 0x13, over => 0x14, 562 pick => 0x15, swap => 0x16, 563 rot => 0x17, xderef => 0x18, 564 565 abs => 0x19, and => 0x1a, 566 div => 0x1b, minus => 0x1c, 567 mod => 0x1d, mul => 0x1e, 568 neg => 0x1f, not => 0x20, 569 or => 0x21, plus => 0x22, 570 shl => 0x24, shr => 0x25, 571 shra => 0x26, xor => 0x27, 572 ); 573 574 my %DW_OP_complex = ( # used in specific subroutines 575 constu => 0x10, # uleb128 576 consts => 0x11, # sleb128 577 plus_uconst => 0x23, # uleb128 578 lit0 => 0x30, # add 0-31 to opcode 579 reg0 => 0x50, # add 0-31 to opcode 580 breg0 => 0x70, # add 0-31 to opcole, sleb128 581 regx => 0x90, # uleb28 582 fbreg => 0x91, # sleb128 583 bregx => 0x92, # uleb128, sleb128 584 piece => 0x93, # uleb128 585 ); 586 587 # Following constants are defined in x86_64 ABI supplement, for 588 # example available at https://www.uclibc.org/docs/psABI-x86_64.pdf, 589 # see section 3.7 "Stack Unwind Algorithm". 590 my %DW_reg_idx = ( 591 "%rax"=>0, "%rdx"=>1, "%rcx"=>2, "%rbx"=>3, 592 "%rsi"=>4, "%rdi"=>5, "%rbp"=>6, "%rsp"=>7, 593 "%r8" =>8, "%r9" =>9, "%r10"=>10, "%r11"=>11, 594 "%r12"=>12, "%r13"=>13, "%r14"=>14, "%r15"=>15 595 ); 596 597 my ($cfa_reg, $cfa_rsp); 598 my @cfa_stack; 599 600 # [us]leb128 format is variable-length integer representation base 601 # 2^128, with most significant bit of each byte being 0 denoting 602 # *last* most significant digit. See "Variable Length Data" in the 603 # DWARF specification, numbered 7.6 at least in versions 3 and 4. 604 sub sleb128 { 605 use integer; # get right shift extend sign 606 607 my $val = shift; 608 my $sign = ($val < 0) ? -1 : 0; 609 my @ret = (); 610 611 while(1) { 612 push @ret, $val&0x7f; 613 614 # see if remaining bits are same and equal to most 615 # significant bit of the current digit, if so, it's 616 # last digit... 617 last if (($val>>6) == $sign); 618 619 @ret[-1] |= 0x80; 620 $val >>= 7; 621 } 622 623 return @ret; 624 } 625 sub uleb128 { 626 my $val = shift; 627 my @ret = (); 628 629 while(1) { 630 push @ret, $val&0x7f; 631 632 # see if it's last significant digit... 633 last if (($val >>= 7) == 0); 634 635 @ret[-1] |= 0x80; 636 } 637 638 return @ret; 639 } 640 sub const { 641 my $val = shift; 642 643 if ($val >= 0 && $val < 32) { 644 return ($DW_OP_complex{lit0}+$val); 645 } 646 return ($DW_OP_complex{consts}, sleb128($val)); 647 } 648 sub reg { 649 my $val = shift; 650 651 return if ($val !~ m/^(%r\w+)(?:([\+\-])((?:0x)?[0-9a-f]+))?/); 652 653 my $reg = $DW_reg_idx{$1}; 654 my $off = eval ("0 $2 $3"); 655 656 return (($DW_OP_complex{breg0} + $reg), sleb128($off)); 657 # Yes, we use DW_OP_bregX+0 to push register value and not 658 # DW_OP_regX, because latter would require even DW_OP_piece, 659 # which would be a waste under the circumstances. If you have 660 # to use DWP_OP_reg, use "regx:N"... 661 } 662 sub cfa_expression { 663 my $line = shift; 664 my @ret; 665 666 foreach my $token (split(/,\s*/,$line)) { 667 if ($token =~ /^%r/) { 668 push @ret,reg($token); 669 } elsif ($token =~ /((?:0x)?[0-9a-f]+)\((%r\w+)\)/) { 670 push @ret,reg("$2+$1"); 671 } elsif ($token =~ /(\w+):(\-?(?:0x)?[0-9a-f]+)(U?)/i) { 672 my $i = 1*eval($2); 673 push @ret,$DW_OP_complex{$1}, ($3 ? uleb128($i) : sleb128($i)); 674 } elsif (my $i = 1*eval($token) or $token eq "0") { 675 if ($token =~ /^\+/) { 676 push @ret,$DW_OP_complex{plus_uconst},uleb128($i); 677 } else { 678 push @ret,const($i); 679 } 680 } else { 681 push @ret,$DW_OP_simple{$token}; 682 } 683 } 684 685 # Finally we return DW_CFA_def_cfa_expression, 15, followed by 686 # length of the expression and of course the expression itself. 687 return (15,scalar(@ret),@ret); 688 } 689 sub re { 690 my ($class, $line) = @_; 691 my $self = {}; 692 my $ret; 693 694 if ($$line =~ s/^\s*\.cfi_(\w+)\s*//) { 695 bless $self,$class; 696 $ret = $self; 697 undef $self->{value}; 698 my $dir = $1; 699 700 SWITCH: for ($dir) { 701 # What is $cfa_rsp? Effectively it's difference between %rsp 702 # value and current CFA, Canonical Frame Address, which is 703 # why it starts with -8. Recall that CFA is top of caller's 704 # stack... 705 /startproc/ && do { ($cfa_reg, $cfa_rsp) = ("%rsp", -8); last; }; 706 /endproc/ && do { ($cfa_reg, $cfa_rsp) = ("%rsp", 0); 707 # .cfi_remember_state directives that are not 708 # matched with .cfi_restore_state are 709 # unnecessary. 710 die "unpaired .cfi_remember_state" if (@cfa_stack); 711 last; 712 }; 713 /def_cfa_register/ 714 && do { $cfa_reg = $$line; last; }; 715 /def_cfa_offset/ 716 && do { $cfa_rsp = -1*eval($$line) if ($cfa_reg eq "%rsp"); 717 last; 718 }; 719 /adjust_cfa_offset/ 720 && do { $cfa_rsp -= 1*eval($$line) if ($cfa_reg eq "%rsp"); 721 last; 722 }; 723 /def_cfa/ && do { if ($$line =~ /(%r\w+)\s*,\s*(.+)/) { 724 $cfa_reg = $1; 725 $cfa_rsp = -1*eval($2) if ($cfa_reg eq "%rsp"); 726 } 727 last; 728 }; 729 /push/ && do { $dir = undef; 730 $cfa_rsp -= 8; 731 if ($cfa_reg eq "%rsp") { 732 $self->{value} = ".cfi_adjust_cfa_offset\t8\n"; 733 } 734 $self->{value} .= ".cfi_offset\t$$line,$cfa_rsp"; 735 last; 736 }; 737 /pop/ && do { $dir = undef; 738 $cfa_rsp += 8; 739 if ($cfa_reg eq "%rsp") { 740 $self->{value} = ".cfi_adjust_cfa_offset\t-8\n"; 741 } 742 $self->{value} .= ".cfi_restore\t$$line"; 743 last; 744 }; 745 /cfa_expression/ 746 && do { $dir = undef; 747 $self->{value} = ".cfi_escape\t" . 748 join(",", map(sprintf("0x%02x", $_), 749 cfa_expression($$line))); 750 last; 751 }; 752 /remember_state/ 753 && do { push @cfa_stack, [$cfa_reg, $cfa_rsp]; 754 last; 755 }; 756 /restore_state/ 757 && do { ($cfa_reg, $cfa_rsp) = @{pop @cfa_stack}; 758 last; 759 }; 760 } 761 762 $self->{value} = ".cfi_$dir\t$$line" if ($dir); 763 764 $$line = ""; 765 } 766 767 return $ret; 768 } 769 sub out { 770 my $self = shift; 771 return ($elf ? $self->{value} : undef); 772 } 773} 774{ package directive; # pick up directives, which start with . 775 sub re { 776 my ($class, $line) = @_; 777 my $self = {}; 778 my $ret; 779 my $dir; 780 781 # chain-call to cfi_directive 782 $ret = cfi_directive->re($line) and return $ret; 783 784 if ($$line =~ /^\s*(\.\w+)/) { 785 bless $self,$class; 786 $dir = $1; 787 $ret = $self; 788 undef $self->{value}; 789 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 790 791 SWITCH: for ($dir) { 792 /\.global|\.globl|\.extern/ 793 && do { $globals{$$line} = $prefix . $$line; 794 $$line = $globals{$$line} if ($prefix); 795 last; 796 }; 797 /\.type/ && do { my ($sym,$type,$narg) = split(',',$$line); 798 if ($type eq "\@function") { 799 undef $current_function; 800 $current_function->{name} = $sym; 801 $current_function->{abi} = "svr4"; 802 $current_function->{narg} = $narg; 803 $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE"; 804 } elsif ($type eq "\@abi-omnipotent") { 805 undef $current_function; 806 $current_function->{name} = $sym; 807 $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE"; 808 } 809 $$line =~ s/\@abi\-omnipotent/\@function/; 810 $$line =~ s/\@function.*/\@function/; 811 last; 812 }; 813 /\.asciz/ && do { if ($$line =~ /^"(.*)"$/) { 814 $dir = ".byte"; 815 $$line = join(",",unpack("C*",$1),0); 816 } 817 last; 818 }; 819 /\.rva|\.long|\.quad/ 820 && do { $$line =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; 821 $$line =~ s/\.L/$decor/g; 822 last; 823 }; 824 } 825 826 if ($gas) { 827 $self->{value} = $dir . "\t" . $$line; 828 829 if ($dir =~ /\.extern/) { 830 $self->{value} = ""; # swallow extern 831 } elsif (!$elf && $dir =~ /\.type/) { 832 $self->{value} = ""; 833 $self->{value} = ".def\t" . ($globals{$1} or $1) . ";\t" . 834 (defined($globals{$1})?".scl 2;":".scl 3;") . 835 "\t.type 32;\t.endef" 836 if ($win64 && $$line =~ /([^,]+),\@function/); 837 } elsif (!$elf && $dir =~ /\.size/) { 838 $self->{value} = ""; 839 if (defined($current_function)) { 840 $self->{value} .= "${decor}SEH_end_$current_function->{name}:" 841 if ($win64 && $current_function->{abi} eq "svr4"); 842 undef $current_function; 843 } 844 } elsif (!$elf && $dir =~ /\.align/) { 845 $self->{value} = ".p2align\t" . (log($$line)/log(2)); 846 } elsif ($dir eq ".section") { 847 $current_segment=$$line; 848 if (!$elf && $current_segment eq ".init") { 849 if ($flavour eq "macosx") { $self->{value} = ".mod_init_func"; } 850 elsif ($flavour eq "mingw64") { $self->{value} = ".section\t.ctors"; } 851 } 852 } elsif ($dir =~ /\.(text|data)/) { 853 $current_segment=".$1"; 854 } elsif ($dir =~ /\.hidden/) { 855 if ($flavour eq "macosx") { $self->{value} = ".private_extern\t$prefix$$line"; } 856 elsif ($flavour eq "mingw64") { $self->{value} = ""; } 857 } elsif ($dir =~ /\.comm/) { 858 $self->{value} = "$dir\t$prefix$$line"; 859 $self->{value} =~ s|,([0-9]+),([0-9]+)$|",$1,".log($2)/log(2)|e if ($flavour eq "macosx"); 860 } 861 $$line = ""; 862 return $self; 863 } 864 865 # non-gas case or nasm/masm 866 SWITCH: for ($dir) { 867 /\.text/ && do { my $v=undef; 868 if ($nasm) { 869 $v="section .text code align=64\n"; 870 } else { 871 $v="$current_segment\tENDS\n" if ($current_segment); 872 $current_segment = ".text\$"; 873 $v.="$current_segment\tSEGMENT "; 874 $v.=$masm>=$masmref ? "ALIGN(256)" : "PAGE"; 875 $v.=" 'CODE'"; 876 } 877 $self->{value} = $v; 878 last; 879 }; 880 /\.data/ && do { my $v=undef; 881 if ($nasm) { 882 $v="section .data data align=8\n"; 883 } else { 884 $v="$current_segment\tENDS\n" if ($current_segment); 885 $current_segment = "_DATA"; 886 $v.="$current_segment\tSEGMENT"; 887 } 888 $self->{value} = $v; 889 last; 890 }; 891 /\.section/ && do { my $v=undef; 892 $$line =~ s/([^,]*).*/$1/; 893 $$line = ".CRT\$XCU" if ($$line eq ".init"); 894 if ($nasm) { 895 $v="section $$line"; 896 if ($$line=~/\.([px])data/) { 897 $v.=" rdata align="; 898 $v.=$1 eq "p"? 4 : 8; 899 } elsif ($$line=~/\.CRT\$/i) { 900 $v.=" rdata align=8"; 901 } 902 } else { 903 $v="$current_segment\tENDS\n" if ($current_segment); 904 $v.="$$line\tSEGMENT"; 905 if ($$line=~/\.([px])data/) { 906 $v.=" READONLY"; 907 $v.=" ALIGN(".($1 eq "p" ? 4 : 8).")" if ($masm>=$masmref); 908 } elsif ($$line=~/\.CRT\$/i) { 909 $v.=" READONLY "; 910 $v.=$masm>=$masmref ? "ALIGN(8)" : "DWORD"; 911 } 912 } 913 $current_segment = $$line; 914 $self->{value} = $v; 915 last; 916 }; 917 /\.extern/ && do { $self->{value} = "EXTERN\t".$$line; 918 $self->{value} .= ":NEAR" if ($masm); 919 last; 920 }; 921 /\.globl|.global/ 922 && do { $self->{value} = $masm?"PUBLIC":"global"; 923 $self->{value} .= "\t".$$line; 924 last; 925 }; 926 /\.size/ && do { if (defined($current_function)) { 927 undef $self->{value}; 928 if ($current_function->{abi} eq "svr4") { 929 $self->{value}="${decor}SEH_end_$current_function->{name}:"; 930 $self->{value}.=":\n" if($masm); 931 } 932 $self->{value}.="$current_function->{name}\tENDP" if($masm && $current_function->{name}); 933 undef $current_function; 934 } 935 last; 936 }; 937 /\.align/ && do { my $max = ($masm && $masm>=$masmref) ? 256 : 4096; 938 $self->{value} = "ALIGN\t".($$line>$max?$max:$$line); 939 last; 940 }; 941 /\.(value|long|rva|quad)/ 942 && do { my $sz = substr($1,0,1); 943 my @arr = split(/,\s*/,$$line); 944 my $last = pop(@arr); 945 my $conv = sub { my $var=shift; 946 $var=~s/^(0b[0-1]+)/oct($1)/eig; 947 $var=~s/^0x([0-9a-f]+)/0$1h/ig if ($masm); 948 if ($sz eq "D" && ($current_segment=~/.[px]data/ || $dir eq ".rva")) 949 { $var=~s/^([_a-z\$\@][_a-z0-9\$\@]*)/$nasm?"$1 wrt ..imagebase":"imagerel $1"/egi; } 950 $var; 951 }; 952 953 $sz =~ tr/bvlrq/BWDDQ/; 954 $self->{value} = "\tD$sz\t"; 955 for (@arr) { $self->{value} .= &$conv($_).","; } 956 $self->{value} .= &$conv($last); 957 last; 958 }; 959 /\.byte/ && do { my @str=split(/,\s*/,$$line); 960 map(s/(0b[0-1]+)/oct($1)/eig,@str); 961 map(s/0x([0-9a-f]+)/0$1h/ig,@str) if ($masm); 962 while ($#str>15) { 963 $self->{value}.="DB\t" 964 .join(",",@str[0..15])."\n"; 965 foreach (0..15) { shift @str; } 966 } 967 $self->{value}.="DB\t" 968 .join(",",@str) if (@str); 969 last; 970 }; 971 /\.comm/ && do { my @str=split(/,\s*/,$$line); 972 my $v=undef; 973 if ($nasm) { 974 $v.="common $prefix@str[0] @str[1]"; 975 } else { 976 $v="$current_segment\tENDS\n" if ($current_segment); 977 $current_segment = "_DATA"; 978 $v.="$current_segment\tSEGMENT\n"; 979 $v.="COMM @str[0]:DWORD:".@str[1]/4; 980 } 981 $self->{value} = $v; 982 last; 983 }; 984 } 985 $$line = ""; 986 } 987 988 $ret; 989 } 990 sub out { 991 my $self = shift; 992 $self->{value}; 993 } 994} 995 996# Upon initial x86_64 introduction SSE>2 extensions were not introduced 997# yet. In order not to be bothered by tracing exact assembler versions, 998# but at the same time to provide a bare security minimum of AES-NI, we 999# hard-code some instructions. Extensions past AES-NI on the other hand 1000# are traced by examining assembler version in individual perlasm 1001# modules... 1002 1003my %regrm = ( "%eax"=>0, "%ecx"=>1, "%edx"=>2, "%ebx"=>3, 1004 "%esp"=>4, "%ebp"=>5, "%esi"=>6, "%edi"=>7 ); 1005 1006sub rex { 1007 my $opcode=shift; 1008 my ($dst,$src,$rex)=@_; 1009 1010 $rex|=0x04 if($dst>=8); 1011 $rex|=0x01 if($src>=8); 1012 push @$opcode,($rex|0x40) if ($rex); 1013} 1014 1015my $movq = sub { # elderly gas can't handle inter-register movq 1016 my $arg = shift; 1017 my @opcode=(0x66); 1018 if ($arg =~ /%xmm([0-9]+),\s*%r(\w+)/) { 1019 my ($src,$dst)=($1,$2); 1020 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } 1021 rex(\@opcode,$src,$dst,0x8); 1022 push @opcode,0x0f,0x7e; 1023 push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M 1024 @opcode; 1025 } elsif ($arg =~ /%r(\w+),\s*%xmm([0-9]+)/) { 1026 my ($src,$dst)=($2,$1); 1027 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } 1028 rex(\@opcode,$src,$dst,0x8); 1029 push @opcode,0x0f,0x6e; 1030 push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M 1031 @opcode; 1032 } else { 1033 (); 1034 } 1035}; 1036 1037my $pextrd = sub { 1038 if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*(%\w+)/) { 1039 my @opcode=(0x66); 1040 my $imm=$1; 1041 my $src=$2; 1042 my $dst=$3; 1043 if ($dst =~ /%r([0-9]+)d/) { $dst = $1; } 1044 elsif ($dst =~ /%e/) { $dst = $regrm{$dst}; } 1045 rex(\@opcode,$src,$dst); 1046 push @opcode,0x0f,0x3a,0x16; 1047 push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M 1048 push @opcode,$imm; 1049 @opcode; 1050 } else { 1051 (); 1052 } 1053}; 1054 1055my $pinsrd = sub { 1056 if (shift =~ /\$([0-9]+),\s*(%\w+),\s*%xmm([0-9]+)/) { 1057 my @opcode=(0x66); 1058 my $imm=$1; 1059 my $src=$2; 1060 my $dst=$3; 1061 if ($src =~ /%r([0-9]+)/) { $src = $1; } 1062 elsif ($src =~ /%e/) { $src = $regrm{$src}; } 1063 rex(\@opcode,$dst,$src); 1064 push @opcode,0x0f,0x3a,0x22; 1065 push @opcode,0xc0|(($dst&7)<<3)|($src&7); # ModR/M 1066 push @opcode,$imm; 1067 @opcode; 1068 } else { 1069 (); 1070 } 1071}; 1072 1073my $pshufb = sub { 1074 if (shift =~ /%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1075 my @opcode=(0x66); 1076 rex(\@opcode,$2,$1); 1077 push @opcode,0x0f,0x38,0x00; 1078 push @opcode,0xc0|($1&7)|(($2&7)<<3); # ModR/M 1079 @opcode; 1080 } else { 1081 (); 1082 } 1083}; 1084 1085my $palignr = sub { 1086 if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1087 my @opcode=(0x66); 1088 rex(\@opcode,$3,$2); 1089 push @opcode,0x0f,0x3a,0x0f; 1090 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M 1091 push @opcode,$1; 1092 @opcode; 1093 } else { 1094 (); 1095 } 1096}; 1097 1098my $pclmulqdq = sub { 1099 if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1100 my @opcode=(0x66); 1101 rex(\@opcode,$3,$2); 1102 push @opcode,0x0f,0x3a,0x44; 1103 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M 1104 my $c=$1; 1105 push @opcode,$c=~/^0/?oct($c):$c; 1106 @opcode; 1107 } else { 1108 (); 1109 } 1110}; 1111 1112my $rdrand = sub { 1113 if (shift =~ /%[er](\w+)/) { 1114 my @opcode=(); 1115 my $dst=$1; 1116 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } 1117 rex(\@opcode,0,$dst,8); 1118 push @opcode,0x0f,0xc7,0xf0|($dst&7); 1119 @opcode; 1120 } else { 1121 (); 1122 } 1123}; 1124 1125my $rdseed = sub { 1126 if (shift =~ /%[er](\w+)/) { 1127 my @opcode=(); 1128 my $dst=$1; 1129 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } 1130 rex(\@opcode,0,$dst,8); 1131 push @opcode,0x0f,0xc7,0xf8|($dst&7); 1132 @opcode; 1133 } else { 1134 (); 1135 } 1136}; 1137 1138# Not all AVX-capable assemblers recognize AMD XOP extension. Since we 1139# are using only two instructions hand-code them in order to be excused 1140# from chasing assembler versions... 1141 1142sub rxb { 1143 my $opcode=shift; 1144 my ($dst,$src1,$src2,$rxb)=@_; 1145 1146 $rxb|=0x7<<5; 1147 $rxb&=~(0x04<<5) if($dst>=8); 1148 $rxb&=~(0x01<<5) if($src1>=8); 1149 $rxb&=~(0x02<<5) if($src2>=8); 1150 push @$opcode,$rxb; 1151} 1152 1153my $vprotd = sub { 1154 if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1155 my @opcode=(0x8f); 1156 rxb(\@opcode,$3,$2,-1,0x08); 1157 push @opcode,0x78,0xc2; 1158 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M 1159 my $c=$1; 1160 push @opcode,$c=~/^0/?oct($c):$c; 1161 @opcode; 1162 } else { 1163 (); 1164 } 1165}; 1166 1167my $vprotq = sub { 1168 if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1169 my @opcode=(0x8f); 1170 rxb(\@opcode,$3,$2,-1,0x08); 1171 push @opcode,0x78,0xc3; 1172 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M 1173 my $c=$1; 1174 push @opcode,$c=~/^0/?oct($c):$c; 1175 @opcode; 1176 } else { 1177 (); 1178 } 1179}; 1180 1181# Intel Control-flow Enforcement Technology extension. All functions and 1182# indirect branch targets will have to start with this instruction... 1183 1184my $endbranch = sub { 1185 (0xf3,0x0f,0x1e,0xfa); 1186}; 1187 1188######################################################################## 1189 1190if ($nasm) { 1191 print <<___; 1192default rel 1193%define XMMWORD 1194%define YMMWORD 1195%define ZMMWORD 1196___ 1197} elsif ($masm) { 1198 print <<___; 1199OPTION DOTNAME 1200___ 1201} 1202while(defined(my $line=<>)) { 1203 1204 $line =~ s|\R$||; # Better chomp 1205 1206 $line =~ s|[#!].*$||; # get rid of asm-style comments... 1207 $line =~ s|/\*.*\*/||; # ... and C-style comments... 1208 $line =~ s|^\s+||; # ... and skip whitespaces in beginning 1209 $line =~ s|\s+$||; # ... and at the end 1210 1211 if (my $label=label->re(\$line)) { print $label->out(); } 1212 1213 if (my $directive=directive->re(\$line)) { 1214 printf "%s",$directive->out(); 1215 } elsif (my $opcode=opcode->re(\$line)) { 1216 my $asm = eval("\$".$opcode->mnemonic()); 1217 1218 if ((ref($asm) eq 'CODE') && scalar(my @bytes=&$asm($line))) { 1219 print $gas?".byte\t":"DB\t",join(',',@bytes),"\n"; 1220 next; 1221 } 1222 1223 my @args; 1224 ARGUMENT: while (1) { 1225 my $arg; 1226 1227 ($arg=register->re(\$line, $opcode))|| 1228 ($arg=const->re(\$line)) || 1229 ($arg=ea->re(\$line, $opcode)) || 1230 ($arg=expr->re(\$line, $opcode)) || 1231 last ARGUMENT; 1232 1233 push @args,$arg; 1234 1235 last ARGUMENT if ($line !~ /^,/); 1236 1237 $line =~ s/^,\s*//; 1238 } # ARGUMENT: 1239 1240 if ($#args>=0) { 1241 my $insn; 1242 my $sz=$opcode->size(); 1243 1244 if ($gas) { 1245 $insn = $opcode->out($#args>=1?$args[$#args]->size():$sz); 1246 @args = map($_->out($sz),@args); 1247 printf "\t%s\t%s",$insn,join(",",@args); 1248 } else { 1249 $insn = $opcode->out(); 1250 foreach (@args) { 1251 my $arg = $_->out(); 1252 # $insn.=$sz compensates for movq, pinsrw, ... 1253 if ($arg =~ /^xmm[0-9]+$/) { $insn.=$sz; $sz="x" if(!$sz); last; } 1254 if ($arg =~ /^ymm[0-9]+$/) { $insn.=$sz; $sz="y" if(!$sz); last; } 1255 if ($arg =~ /^zmm[0-9]+$/) { $insn.=$sz; $sz="z" if(!$sz); last; } 1256 if ($arg =~ /^mm[0-9]+$/) { $insn.=$sz; $sz="q" if(!$sz); last; } 1257 } 1258 @args = reverse(@args); 1259 undef $sz if ($nasm && $opcode->mnemonic() eq "lea"); 1260 printf "\t%s\t%s",$insn,join(",",map($_->out($sz),@args)); 1261 } 1262 } else { 1263 printf "\t%s",$opcode->out(); 1264 } 1265 } 1266 1267 print $line,"\n"; 1268} 1269 1270print "$cet_property" if ($cet_property); 1271print "\n$current_segment\tENDS\n" if ($current_segment && $masm); 1272print "END\n" if ($masm); 1273 1274close STDOUT or die "error closing STDOUT: $!;" 1275 1276 ################################################# 1277# Cross-reference x86_64 ABI "card" 1278# 1279# Unix Win64 1280# %rax * * 1281# %rbx - - 1282# %rcx #4 #1 1283# %rdx #3 #2 1284# %rsi #2 - 1285# %rdi #1 - 1286# %rbp - - 1287# %rsp - - 1288# %r8 #5 #3 1289# %r9 #6 #4 1290# %r10 * * 1291# %r11 * * 1292# %r12 - - 1293# %r13 - - 1294# %r14 - - 1295# %r15 - - 1296# 1297# (*) volatile register 1298# (-) preserved by callee 1299# (#) Nth argument, volatile 1300# 1301# In Unix terms top of stack is argument transfer area for arguments 1302# which could not be accommodated in registers. Or in other words 7th 1303# [integer] argument resides at 8(%rsp) upon function entry point. 1304# 128 bytes above %rsp constitute a "red zone" which is not touched 1305# by signal handlers and can be used as temporal storage without 1306# allocating a frame. 1307# 1308# In Win64 terms N*8 bytes on top of stack is argument transfer area, 1309# which belongs to/can be overwritten by callee. N is the number of 1310# arguments passed to callee, *but* not less than 4! This means that 1311# upon function entry point 5th argument resides at 40(%rsp), as well 1312# as that 32 bytes from 8(%rsp) can always be used as temporal 1313# storage [without allocating a frame]. One can actually argue that 1314# one can assume a "red zone" above stack pointer under Win64 as well. 1315# Point is that at apparently no occasion Windows kernel would alter 1316# the area above user stack pointer in true asynchronous manner... 1317# 1318# All the above means that if assembler programmer adheres to Unix 1319# register and stack layout, but disregards the "red zone" existence, 1320# it's possible to use following prologue and epilogue to "gear" from 1321# Unix to Win64 ABI in leaf functions with not more than 6 arguments. 1322# 1323# omnipotent_function: 1324# ifdef WIN64 1325# movq %rdi,8(%rsp) 1326# movq %rsi,16(%rsp) 1327# movq %rcx,%rdi ; if 1st argument is actually present 1328# movq %rdx,%rsi ; if 2nd argument is actually ... 1329# movq %r8,%rdx ; if 3rd argument is ... 1330# movq %r9,%rcx ; if 4th argument ... 1331# movq 40(%rsp),%r8 ; if 5th ... 1332# movq 48(%rsp),%r9 ; if 6th ... 1333# endif 1334# ... 1335# ifdef WIN64 1336# movq 8(%rsp),%rdi 1337# movq 16(%rsp),%rsi 1338# endif 1339# ret 1340# 1341 ################################################# 1342# Win64 SEH, Structured Exception Handling. 1343# 1344# Unlike on Unix systems(*) lack of Win64 stack unwinding information 1345# has undesired side-effect at run-time: if an exception is raised in 1346# assembler subroutine such as those in question (basically we're 1347# referring to segmentation violations caused by malformed input 1348# parameters), the application is briskly terminated without invoking 1349# any exception handlers, most notably without generating memory dump 1350# or any user notification whatsoever. This poses a problem. It's 1351# possible to address it by registering custom language-specific 1352# handler that would restore processor context to the state at 1353# subroutine entry point and return "exception is not handled, keep 1354# unwinding" code. Writing such handler can be a challenge... But it's 1355# doable, though requires certain coding convention. Consider following 1356# snippet: 1357# 1358# .type function,@function 1359# function: 1360# movq %rsp,%rax # copy rsp to volatile register 1361# pushq %r15 # save non-volatile registers 1362# pushq %rbx 1363# pushq %rbp 1364# movq %rsp,%r11 1365# subq %rdi,%r11 # prepare [variable] stack frame 1366# andq $-64,%r11 1367# movq %rax,0(%r11) # check for exceptions 1368# movq %r11,%rsp # allocate [variable] stack frame 1369# movq %rax,0(%rsp) # save original rsp value 1370# magic_point: 1371# ... 1372# movq 0(%rsp),%rcx # pull original rsp value 1373# movq -24(%rcx),%rbp # restore non-volatile registers 1374# movq -16(%rcx),%rbx 1375# movq -8(%rcx),%r15 1376# movq %rcx,%rsp # restore original rsp 1377# magic_epilogue: 1378# ret 1379# .size function,.-function 1380# 1381# The key is that up to magic_point copy of original rsp value remains 1382# in chosen volatile register and no non-volatile register, except for 1383# rsp, is modified. While past magic_point rsp remains constant till 1384# the very end of the function. In this case custom language-specific 1385# exception handler would look like this: 1386# 1387# EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame, 1388# CONTEXT *context,DISPATCHER_CONTEXT *disp) 1389# { ULONG64 *rsp = (ULONG64 *)context->Rax; 1390# ULONG64 rip = context->Rip; 1391# 1392# if (rip >= magic_point) 1393# { rsp = (ULONG64 *)context->Rsp; 1394# if (rip < magic_epilogue) 1395# { rsp = (ULONG64 *)rsp[0]; 1396# context->Rbp = rsp[-3]; 1397# context->Rbx = rsp[-2]; 1398# context->R15 = rsp[-1]; 1399# } 1400# } 1401# context->Rsp = (ULONG64)rsp; 1402# context->Rdi = rsp[1]; 1403# context->Rsi = rsp[2]; 1404# 1405# memcpy (disp->ContextRecord,context,sizeof(CONTEXT)); 1406# RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase, 1407# dips->ControlPc,disp->FunctionEntry,disp->ContextRecord, 1408# &disp->HandlerData,&disp->EstablisherFrame,NULL); 1409# return ExceptionContinueSearch; 1410# } 1411# 1412# It's appropriate to implement this handler in assembler, directly in 1413# function's module. In order to do that one has to know members' 1414# offsets in CONTEXT and DISPATCHER_CONTEXT structures and some constant 1415# values. Here they are: 1416# 1417# CONTEXT.Rax 120 1418# CONTEXT.Rcx 128 1419# CONTEXT.Rdx 136 1420# CONTEXT.Rbx 144 1421# CONTEXT.Rsp 152 1422# CONTEXT.Rbp 160 1423# CONTEXT.Rsi 168 1424# CONTEXT.Rdi 176 1425# CONTEXT.R8 184 1426# CONTEXT.R9 192 1427# CONTEXT.R10 200 1428# CONTEXT.R11 208 1429# CONTEXT.R12 216 1430# CONTEXT.R13 224 1431# CONTEXT.R14 232 1432# CONTEXT.R15 240 1433# CONTEXT.Rip 248 1434# CONTEXT.Xmm6 512 1435# sizeof(CONTEXT) 1232 1436# DISPATCHER_CONTEXT.ControlPc 0 1437# DISPATCHER_CONTEXT.ImageBase 8 1438# DISPATCHER_CONTEXT.FunctionEntry 16 1439# DISPATCHER_CONTEXT.EstablisherFrame 24 1440# DISPATCHER_CONTEXT.TargetIp 32 1441# DISPATCHER_CONTEXT.ContextRecord 40 1442# DISPATCHER_CONTEXT.LanguageHandler 48 1443# DISPATCHER_CONTEXT.HandlerData 56 1444# UNW_FLAG_NHANDLER 0 1445# ExceptionContinueSearch 1 1446# 1447# In order to tie the handler to the function one has to compose 1448# couple of structures: one for .xdata segment and one for .pdata. 1449# 1450# UNWIND_INFO structure for .xdata segment would be 1451# 1452# function_unwind_info: 1453# .byte 9,0,0,0 1454# .rva handler 1455# 1456# This structure designates exception handler for a function with 1457# zero-length prologue, no stack frame or frame register. 1458# 1459# To facilitate composing of .pdata structures, auto-generated "gear" 1460# prologue copies rsp value to rax and denotes next instruction with 1461# .LSEH_begin_{function_name} label. This essentially defines the SEH 1462# styling rule mentioned in the beginning. Position of this label is 1463# chosen in such manner that possible exceptions raised in the "gear" 1464# prologue would be accounted to caller and unwound from latter's frame. 1465# End of function is marked with respective .LSEH_end_{function_name} 1466# label. To summarize, .pdata segment would contain 1467# 1468# .rva .LSEH_begin_function 1469# .rva .LSEH_end_function 1470# .rva function_unwind_info 1471# 1472# Reference to function_unwind_info from .xdata segment is the anchor. 1473# In case you wonder why references are 32-bit .rvas and not 64-bit 1474# .quads. References put into these two segments are required to be 1475# *relative* to the base address of the current binary module, a.k.a. 1476# image base. No Win64 module, be it .exe or .dll, can be larger than 1477# 2GB and thus such relative references can be and are accommodated in 1478# 32 bits. 1479# 1480# Having reviewed the example function code, one can argue that "movq 1481# %rsp,%rax" above is redundant. It is not! Keep in mind that on Unix 1482# rax would contain an undefined value. If this "offends" you, use 1483# another register and refrain from modifying rax till magic_point is 1484# reached, i.e. as if it was a non-volatile register. If more registers 1485# are required prior [variable] frame setup is completed, note that 1486# nobody says that you can have only one "magic point." You can 1487# "liberate" non-volatile registers by denoting last stack off-load 1488# instruction and reflecting it in finer grade unwind logic in handler. 1489# After all, isn't it why it's called *language-specific* handler... 1490# 1491# SE handlers are also involved in unwinding stack when executable is 1492# profiled or debugged. Profiling implies additional limitations that 1493# are too subtle to discuss here. For now it's sufficient to say that 1494# in order to simplify handlers one should either a) offload original 1495# %rsp to stack (like discussed above); or b) if you have a register to 1496# spare for frame pointer, choose volatile one. 1497# 1498# (*) Note that we're talking about run-time, not debug-time. Lack of 1499# unwind information makes debugging hard on both Windows and 1500# Unix. "Unlike" refers to the fact that on Unix signal handler 1501# will always be invoked, core dumped and appropriate exit code 1502# returned to parent (for user notification). 1503