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 .*/) 115{ 116 $gnuas=1; 117} 118 119my $cet_property; 120if ($flavour =~ /elf/) { 121 # Always generate .note.gnu.property section for ELF outputs to 122 # mark Intel CET support since all input files must be marked 123 # with Intel CET support in order for linker to mark output with 124 # Intel CET support. 125 my $p2align=3; $p2align=2 if ($flavour eq "elf32"); 126 my $section='.note.gnu.property, #alloc'; 127 $section='".note.gnu.property", "a"' if $gnuas; 128 $cet_property = <<_____; 129 .section $section 130 .p2align $p2align 131 .long 1f - 0f 132 .long 4f - 1f 133 .long 5 1340: 135 # "GNU" encoded with .byte, since .asciz isn't supported 136 # on Solaris. 137 .byte 0x47 138 .byte 0x4e 139 .byte 0x55 140 .byte 0 1411: 142 .p2align $p2align 143 .long 0xc0000002 144 .long 3f - 2f 1452: 146 .long 3 1473: 148 .p2align $p2align 1494: 150_____ 151} 152 153my $current_segment; 154my $current_function; 155my %globals; 156 157{ package opcode; # pick up opcodes 158 sub re { 159 my ($class, $line) = @_; 160 my $self = {}; 161 my $ret; 162 163 if ($$line =~ /^([a-z][a-z0-9]*)/i) { 164 bless $self,$class; 165 $self->{op} = $1; 166 $ret = $self; 167 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 168 169 undef $self->{sz}; 170 if ($self->{op} =~ /^(movz)x?([bw]).*/) { # movz is pain... 171 $self->{op} = $1; 172 $self->{sz} = $2; 173 } elsif ($self->{op} =~ /call|jmp/) { 174 $self->{sz} = ""; 175 } elsif ($self->{op} =~ /^p/ && $' !~ /^(ush|op|insrw)/) { # SSEn 176 $self->{sz} = ""; 177 } elsif ($self->{op} =~ /^[vk]/) { # VEX or k* such as kmov 178 $self->{sz} = ""; 179 } elsif ($self->{op} =~ /mov[dq]/ && $$line =~ /%xmm/) { 180 $self->{sz} = ""; 181 } elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) { 182 $self->{op} = $1; 183 $self->{sz} = $2; 184 } 185 } 186 $ret; 187 } 188 sub size { 189 my ($self, $sz) = @_; 190 $self->{sz} = $sz if (defined($sz) && !defined($self->{sz})); 191 $self->{sz}; 192 } 193 sub out { 194 my $self = shift; 195 if ($gas) { 196 if ($self->{op} eq "movz") { # movz is pain... 197 sprintf "%s%s%s",$self->{op},$self->{sz},shift; 198 } elsif ($self->{op} =~ /^set/) { 199 "$self->{op}"; 200 } elsif ($self->{op} eq "ret") { 201 my $epilogue = ""; 202 if ($win64 && $current_function->{abi} eq "svr4") { 203 $epilogue = "movq 8(%rsp),%rdi\n\t" . 204 "movq 16(%rsp),%rsi\n\t"; 205 } 206 $epilogue . ".byte 0xf3,0xc3"; 207 } elsif ($self->{op} eq "call" && !$elf && $current_segment eq ".init") { 208 ".p2align\t3\n\t.quad"; 209 } else { 210 "$self->{op}$self->{sz}"; 211 } 212 } else { 213 $self->{op} =~ s/^movz/movzx/; 214 if ($self->{op} eq "ret") { 215 $self->{op} = ""; 216 if ($win64 && $current_function->{abi} eq "svr4") { 217 $self->{op} = "mov rdi,QWORD$PTR\[8+rsp\]\t;WIN64 epilogue\n\t". 218 "mov rsi,QWORD$PTR\[16+rsp\]\n\t"; 219 } 220 $self->{op} .= "DB\t0F3h,0C3h\t\t;repret"; 221 } elsif ($self->{op} =~ /^(pop|push)f/) { 222 $self->{op} .= $self->{sz}; 223 } elsif ($self->{op} eq "call" && $current_segment eq ".CRT\$XCU") { 224 $self->{op} = "\tDQ"; 225 } 226 $self->{op}; 227 } 228 } 229 sub mnemonic { 230 my ($self, $op) = @_; 231 $self->{op}=$op if (defined($op)); 232 $self->{op}; 233 } 234} 235{ package const; # pick up constants, which start with $ 236 sub re { 237 my ($class, $line) = @_; 238 my $self = {}; 239 my $ret; 240 241 if ($$line =~ /^\$([^,]+)/) { 242 bless $self, $class; 243 $self->{value} = $1; 244 $ret = $self; 245 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 246 } 247 $ret; 248 } 249 sub out { 250 my $self = shift; 251 252 $self->{value} =~ s/\b(0b[0-1]+)/oct($1)/eig; 253 if ($gas) { 254 # Solaris /usr/ccs/bin/as can't handle multiplications 255 # in $self->{value} 256 my $value = $self->{value}; 257 no warnings; # oct might complain about overflow, ignore here... 258 $value =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi; 259 if ($value =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg) { 260 $self->{value} = $value; 261 } 262 sprintf "\$%s",$self->{value}; 263 } else { 264 my $value = $self->{value}; 265 $value =~ s/0x([0-9a-f]+)/0$1h/ig if ($masm); 266 sprintf "%s",$value; 267 } 268 } 269} 270{ package ea; # pick up effective addresses: expr(%reg,%reg,scale) 271 272 my %szmap = ( b=>"BYTE$PTR", w=>"WORD$PTR", 273 l=>"DWORD$PTR", d=>"DWORD$PTR", 274 q=>"QWORD$PTR", o=>"OWORD$PTR", 275 x=>"XMMWORD$PTR", y=>"YMMWORD$PTR", 276 z=>"ZMMWORD$PTR" ) if (!$gas); 277 278 sub re { 279 my ($class, $line, $opcode) = @_; 280 my $self = {}; 281 my $ret; 282 283 # optional * ----vvv--- appears in indirect jmp/call 284 if ($$line =~ /^(\*?)([^\(,]*)\(([%\w,]+)\)((?:{[^}]+})*)/) { 285 bless $self, $class; 286 $self->{asterisk} = $1; 287 $self->{label} = $2; 288 ($self->{base},$self->{index},$self->{scale})=split(/,/,$3); 289 $self->{scale} = 1 if (!defined($self->{scale})); 290 $self->{opmask} = $4; 291 $ret = $self; 292 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 293 294 if ($win64 && $self->{label} =~ s/\@GOTPCREL//) { 295 die if ($opcode->mnemonic() ne "mov"); 296 $opcode->mnemonic("lea"); 297 } 298 $self->{base} =~ s/^%//; 299 $self->{index} =~ s/^%// if (defined($self->{index})); 300 $self->{opcode} = $opcode; 301 } 302 $ret; 303 } 304 sub size {} 305 sub out { 306 my ($self, $sz) = @_; 307 308 $self->{label} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; 309 $self->{label} =~ s/\.L/$decor/g; 310 311 # Silently convert all EAs to 64-bit. This is required for 312 # elder GNU assembler and results in more compact code, 313 # *but* most importantly AES module depends on this feature! 314 $self->{index} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; 315 $self->{base} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; 316 317 # Solaris /usr/ccs/bin/as can't handle multiplications 318 # in $self->{label}... 319 use integer; 320 $self->{label} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi; 321 $self->{label} =~ s/\b([0-9]+\s*[\*\/\%]\s*[0-9]+)\b/eval($1)/eg; 322 323 # Some assemblers insist on signed presentation of 32-bit 324 # offsets, but sign extension is a tricky business in perl... 325 if ((1<<31)<<1) { 326 $self->{label} =~ s/\b([0-9]+)\b/$1<<32>>32/eg; 327 } else { 328 $self->{label} =~ s/\b([0-9]+)\b/$1>>0/eg; 329 } 330 331 # if base register is %rbp or %r13, see if it's possible to 332 # flip base and index registers [for better performance] 333 if (!$self->{label} && $self->{index} && $self->{scale}==1 && 334 $self->{base} =~ /(rbp|r13)/) { 335 $self->{base} = $self->{index}; $self->{index} = $1; 336 } 337 338 if ($gas) { 339 $self->{label} =~ s/^___imp_/__imp__/ if ($flavour eq "mingw64"); 340 341 if (defined($self->{index})) { 342 sprintf "%s%s(%s,%%%s,%d)%s", 343 $self->{asterisk},$self->{label}, 344 $self->{base}?"%$self->{base}":"", 345 $self->{index},$self->{scale}, 346 $self->{opmask}; 347 } else { 348 sprintf "%s%s(%%%s)%s", $self->{asterisk},$self->{label}, 349 $self->{base},$self->{opmask}; 350 } 351 } else { 352 $self->{label} =~ s/\./\$/g; 353 $self->{label} =~ s/(?<![\w\$\.])0x([0-9a-f]+)/0$1h/ig; 354 $self->{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/); 355 356 my $mnemonic = $self->{opcode}->mnemonic(); 357 ($self->{asterisk}) && ($sz="q") || 358 ($mnemonic =~ /^v?mov([qd])$/) && ($sz=$1) || 359 ($mnemonic =~ /^v?pinsr([qdwb])$/) && ($sz=$1) || 360 ($mnemonic =~ /^vpbroadcast([qdwb])$/) && ($sz=$1) || 361 ($mnemonic =~ /^v(?!perm)[a-z]+[fi]128$/) && ($sz="x"); 362 363 $self->{opmask} =~ s/%(k[0-7])/$1/; 364 365 if (defined($self->{index})) { 366 sprintf "%s[%s%s*%d%s]%s",$szmap{$sz}, 367 $self->{label}?"$self->{label}+":"", 368 $self->{index},$self->{scale}, 369 $self->{base}?"+$self->{base}":"", 370 $self->{opmask}; 371 } elsif ($self->{base} eq "rip") { 372 sprintf "%s[%s]",$szmap{$sz},$self->{label}; 373 } else { 374 sprintf "%s[%s%s]%s", $szmap{$sz}, 375 $self->{label}?"$self->{label}+":"", 376 $self->{base},$self->{opmask}; 377 } 378 } 379 } 380} 381{ package register; # pick up registers, which start with %. 382 sub re { 383 my ($class, $line, $opcode) = @_; 384 my $self = {}; 385 my $ret; 386 387 # optional * ----vvv--- appears in indirect jmp/call 388 if ($$line =~ /^(\*?)%(\w+)((?:{[^}]+})*)/) { 389 bless $self,$class; 390 $self->{asterisk} = $1; 391 $self->{value} = $2; 392 $self->{opmask} = $3; 393 $opcode->size($self->size()); 394 $ret = $self; 395 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 396 } 397 $ret; 398 } 399 sub size { 400 my $self = shift; 401 my $ret; 402 403 if ($self->{value} =~ /^r[\d]+b$/i) { $ret="b"; } 404 elsif ($self->{value} =~ /^r[\d]+w$/i) { $ret="w"; } 405 elsif ($self->{value} =~ /^r[\d]+d$/i) { $ret="l"; } 406 elsif ($self->{value} =~ /^r[\w]+$/i) { $ret="q"; } 407 elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; } 408 elsif ($self->{value} =~ /^[\w]{2}l$/i) { $ret="b"; } 409 elsif ($self->{value} =~ /^[\w]{2}$/i) { $ret="w"; } 410 elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; } 411 412 $ret; 413 } 414 sub out { 415 my $self = shift; 416 if ($gas) { sprintf "%s%%%s%s", $self->{asterisk}, 417 $self->{value}, 418 $self->{opmask}; } 419 else { $self->{opmask} =~ s/%(k[0-7])/$1/; 420 $self->{value}.$self->{opmask}; } 421 } 422} 423{ package label; # pick up labels, which end with : 424 sub re { 425 my ($class, $line) = @_; 426 my $self = {}; 427 my $ret; 428 429 if ($$line =~ /(^[\.\w]+)\:/) { 430 bless $self,$class; 431 $self->{value} = $1; 432 $ret = $self; 433 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 434 435 $self->{value} =~ s/^\.L/$decor/; 436 } 437 $ret; 438 } 439 sub out { 440 my $self = shift; 441 442 if ($gas) { 443 my $func = ($globals{$self->{value}} or $self->{value}) . ":"; 444 if ($win64 && $current_function->{name} eq $self->{value} 445 && $current_function->{abi} eq "svr4") { 446 $func .= "\n"; 447 $func .= " movq %rdi,8(%rsp)\n"; 448 $func .= " movq %rsi,16(%rsp)\n"; 449 $func .= " movq %rsp,%rax\n"; 450 $func .= "${decor}SEH_begin_$current_function->{name}:\n"; 451 my $narg = $current_function->{narg}; 452 $narg=6 if (!defined($narg)); 453 $func .= " movq %rcx,%rdi\n" if ($narg>0); 454 $func .= " movq %rdx,%rsi\n" if ($narg>1); 455 $func .= " movq %r8,%rdx\n" if ($narg>2); 456 $func .= " movq %r9,%rcx\n" if ($narg>3); 457 $func .= " movq 40(%rsp),%r8\n" if ($narg>4); 458 $func .= " movq 48(%rsp),%r9\n" if ($narg>5); 459 } 460 $func; 461 } elsif ($self->{value} ne "$current_function->{name}") { 462 # Make all labels in masm global. 463 $self->{value} .= ":" if ($masm); 464 $self->{value} . ":"; 465 } elsif ($win64 && $current_function->{abi} eq "svr4") { 466 my $func = "$current_function->{name}" . 467 ($nasm ? ":" : "\tPROC $current_function->{scope}") . 468 "\n"; 469 $func .= " mov QWORD$PTR\[8+rsp\],rdi\t;WIN64 prologue\n"; 470 $func .= " mov QWORD$PTR\[16+rsp\],rsi\n"; 471 $func .= " mov rax,rsp\n"; 472 $func .= "${decor}SEH_begin_$current_function->{name}:"; 473 $func .= ":" if ($masm); 474 $func .= "\n"; 475 my $narg = $current_function->{narg}; 476 $narg=6 if (!defined($narg)); 477 $func .= " mov rdi,rcx\n" if ($narg>0); 478 $func .= " mov rsi,rdx\n" if ($narg>1); 479 $func .= " mov rdx,r8\n" if ($narg>2); 480 $func .= " mov rcx,r9\n" if ($narg>3); 481 $func .= " mov r8,QWORD$PTR\[40+rsp\]\n" if ($narg>4); 482 $func .= " mov r9,QWORD$PTR\[48+rsp\]\n" if ($narg>5); 483 $func .= "\n"; 484 } else { 485 "$current_function->{name}". 486 ($nasm ? ":" : "\tPROC $current_function->{scope}"); 487 } 488 } 489} 490{ package expr; # pick up expressions 491 sub re { 492 my ($class, $line, $opcode) = @_; 493 my $self = {}; 494 my $ret; 495 496 if ($$line =~ /(^[^,]+)/) { 497 bless $self,$class; 498 $self->{value} = $1; 499 $ret = $self; 500 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 501 502 $self->{value} =~ s/\@PLT// if (!$elf); 503 $self->{value} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; 504 $self->{value} =~ s/\.L/$decor/g; 505 $self->{opcode} = $opcode; 506 } 507 $ret; 508 } 509 sub out { 510 my $self = shift; 511 if ($nasm && $self->{opcode}->mnemonic()=~m/^j(?![re]cxz)/) { 512 "NEAR ".$self->{value}; 513 } else { 514 $self->{value}; 515 } 516 } 517} 518{ package cfi_directive; 519 # CFI directives annotate instructions that are significant for 520 # stack unwinding procedure compliant with DWARF specification, 521 # see http://dwarfstd.org/. Besides naturally expected for this 522 # script platform-specific filtering function, this module adds 523 # three auxiliary synthetic directives not recognized by [GNU] 524 # assembler: 525 # 526 # - .cfi_push to annotate push instructions in prologue, which 527 # translates to .cfi_adjust_cfa_offset (if needed) and 528 # .cfi_offset; 529 # - .cfi_pop to annotate pop instructions in epilogue, which 530 # translates to .cfi_adjust_cfa_offset (if needed) and 531 # .cfi_restore; 532 # - [and most notably] .cfi_cfa_expression which encodes 533 # DW_CFA_def_cfa_expression and passes it to .cfi_escape as 534 # byte vector; 535 # 536 # CFA expressions were introduced in DWARF specification version 537 # 3 and describe how to deduce CFA, Canonical Frame Address. This 538 # becomes handy if your stack frame is variable and you can't 539 # spare register for [previous] frame pointer. Suggested directive 540 # syntax is made-up mix of DWARF operator suffixes [subset of] 541 # and references to registers with optional bias. Following example 542 # describes offloaded *original* stack pointer at specific offset 543 # from *current* stack pointer: 544 # 545 # .cfi_cfa_expression %rsp+40,deref,+8 546 # 547 # Final +8 has everything to do with the fact that CFA is defined 548 # as reference to top of caller's stack, and on x86_64 call to 549 # subroutine pushes 8-byte return address. In other words original 550 # stack pointer upon entry to a subroutine is 8 bytes off from CFA. 551 552 # Below constants are taken from "DWARF Expressions" section of the 553 # DWARF specification, section is numbered 7.7 in versions 3 and 4. 554 my %DW_OP_simple = ( # no-arg operators, mapped directly 555 deref => 0x06, dup => 0x12, 556 drop => 0x13, over => 0x14, 557 pick => 0x15, swap => 0x16, 558 rot => 0x17, xderef => 0x18, 559 560 abs => 0x19, and => 0x1a, 561 div => 0x1b, minus => 0x1c, 562 mod => 0x1d, mul => 0x1e, 563 neg => 0x1f, not => 0x20, 564 or => 0x21, plus => 0x22, 565 shl => 0x24, shr => 0x25, 566 shra => 0x26, xor => 0x27, 567 ); 568 569 my %DW_OP_complex = ( # used in specific subroutines 570 constu => 0x10, # uleb128 571 consts => 0x11, # sleb128 572 plus_uconst => 0x23, # uleb128 573 lit0 => 0x30, # add 0-31 to opcode 574 reg0 => 0x50, # add 0-31 to opcode 575 breg0 => 0x70, # add 0-31 to opcole, sleb128 576 regx => 0x90, # uleb28 577 fbreg => 0x91, # sleb128 578 bregx => 0x92, # uleb128, sleb128 579 piece => 0x93, # uleb128 580 ); 581 582 # Following constants are defined in x86_64 ABI supplement, for 583 # example available at https://www.uclibc.org/docs/psABI-x86_64.pdf, 584 # see section 3.7 "Stack Unwind Algorithm". 585 my %DW_reg_idx = ( 586 "%rax"=>0, "%rdx"=>1, "%rcx"=>2, "%rbx"=>3, 587 "%rsi"=>4, "%rdi"=>5, "%rbp"=>6, "%rsp"=>7, 588 "%r8" =>8, "%r9" =>9, "%r10"=>10, "%r11"=>11, 589 "%r12"=>12, "%r13"=>13, "%r14"=>14, "%r15"=>15 590 ); 591 592 my ($cfa_reg, $cfa_rsp); 593 my @cfa_stack; 594 595 # [us]leb128 format is variable-length integer representation base 596 # 2^128, with most significant bit of each byte being 0 denoting 597 # *last* most significant digit. See "Variable Length Data" in the 598 # DWARF specification, numbered 7.6 at least in versions 3 and 4. 599 sub sleb128 { 600 use integer; # get right shift extend sign 601 602 my $val = shift; 603 my $sign = ($val < 0) ? -1 : 0; 604 my @ret = (); 605 606 while(1) { 607 push @ret, $val&0x7f; 608 609 # see if remaining bits are same and equal to most 610 # significant bit of the current digit, if so, it's 611 # last digit... 612 last if (($val>>6) == $sign); 613 614 @ret[-1] |= 0x80; 615 $val >>= 7; 616 } 617 618 return @ret; 619 } 620 sub uleb128 { 621 my $val = shift; 622 my @ret = (); 623 624 while(1) { 625 push @ret, $val&0x7f; 626 627 # see if it's last significant digit... 628 last if (($val >>= 7) == 0); 629 630 @ret[-1] |= 0x80; 631 } 632 633 return @ret; 634 } 635 sub const { 636 my $val = shift; 637 638 if ($val >= 0 && $val < 32) { 639 return ($DW_OP_complex{lit0}+$val); 640 } 641 return ($DW_OP_complex{consts}, sleb128($val)); 642 } 643 sub reg { 644 my $val = shift; 645 646 return if ($val !~ m/^(%r\w+)(?:([\+\-])((?:0x)?[0-9a-f]+))?/); 647 648 my $reg = $DW_reg_idx{$1}; 649 my $off = eval ("0 $2 $3"); 650 651 return (($DW_OP_complex{breg0} + $reg), sleb128($off)); 652 # Yes, we use DW_OP_bregX+0 to push register value and not 653 # DW_OP_regX, because latter would require even DW_OP_piece, 654 # which would be a waste under the circumstances. If you have 655 # to use DWP_OP_reg, use "regx:N"... 656 } 657 sub cfa_expression { 658 my $line = shift; 659 my @ret; 660 661 foreach my $token (split(/,\s*/,$line)) { 662 if ($token =~ /^%r/) { 663 push @ret,reg($token); 664 } elsif ($token =~ /((?:0x)?[0-9a-f]+)\((%r\w+)\)/) { 665 push @ret,reg("$2+$1"); 666 } elsif ($token =~ /(\w+):(\-?(?:0x)?[0-9a-f]+)(U?)/i) { 667 my $i = 1*eval($2); 668 push @ret,$DW_OP_complex{$1}, ($3 ? uleb128($i) : sleb128($i)); 669 } elsif (my $i = 1*eval($token) or $token eq "0") { 670 if ($token =~ /^\+/) { 671 push @ret,$DW_OP_complex{plus_uconst},uleb128($i); 672 } else { 673 push @ret,const($i); 674 } 675 } else { 676 push @ret,$DW_OP_simple{$token}; 677 } 678 } 679 680 # Finally we return DW_CFA_def_cfa_expression, 15, followed by 681 # length of the expression and of course the expression itself. 682 return (15,scalar(@ret),@ret); 683 } 684 sub re { 685 my ($class, $line) = @_; 686 my $self = {}; 687 my $ret; 688 689 if ($$line =~ s/^\s*\.cfi_(\w+)\s*//) { 690 bless $self,$class; 691 $ret = $self; 692 undef $self->{value}; 693 my $dir = $1; 694 695 SWITCH: for ($dir) { 696 # What is $cfa_rsp? Effectively it's difference between %rsp 697 # value and current CFA, Canonical Frame Address, which is 698 # why it starts with -8. Recall that CFA is top of caller's 699 # stack... 700 /startproc/ && do { ($cfa_reg, $cfa_rsp) = ("%rsp", -8); last; }; 701 /endproc/ && do { ($cfa_reg, $cfa_rsp) = ("%rsp", 0); 702 # .cfi_remember_state directives that are not 703 # matched with .cfi_restore_state are 704 # unnecessary. 705 die "unpaired .cfi_remember_state" if (@cfa_stack); 706 last; 707 }; 708 /def_cfa_register/ 709 && do { $cfa_reg = $$line; last; }; 710 /def_cfa_offset/ 711 && do { $cfa_rsp = -1*eval($$line) if ($cfa_reg eq "%rsp"); 712 last; 713 }; 714 /adjust_cfa_offset/ 715 && do { $cfa_rsp -= 1*eval($$line) if ($cfa_reg eq "%rsp"); 716 last; 717 }; 718 /def_cfa/ && do { if ($$line =~ /(%r\w+)\s*,\s*(.+)/) { 719 $cfa_reg = $1; 720 $cfa_rsp = -1*eval($2) if ($cfa_reg eq "%rsp"); 721 } 722 last; 723 }; 724 /push/ && do { $dir = undef; 725 $cfa_rsp -= 8; 726 if ($cfa_reg eq "%rsp") { 727 $self->{value} = ".cfi_adjust_cfa_offset\t8\n"; 728 } 729 $self->{value} .= ".cfi_offset\t$$line,$cfa_rsp"; 730 last; 731 }; 732 /pop/ && do { $dir = undef; 733 $cfa_rsp += 8; 734 if ($cfa_reg eq "%rsp") { 735 $self->{value} = ".cfi_adjust_cfa_offset\t-8\n"; 736 } 737 $self->{value} .= ".cfi_restore\t$$line"; 738 last; 739 }; 740 /cfa_expression/ 741 && do { $dir = undef; 742 $self->{value} = ".cfi_escape\t" . 743 join(",", map(sprintf("0x%02x", $_), 744 cfa_expression($$line))); 745 last; 746 }; 747 /remember_state/ 748 && do { push @cfa_stack, [$cfa_reg, $cfa_rsp]; 749 last; 750 }; 751 /restore_state/ 752 && do { ($cfa_reg, $cfa_rsp) = @{pop @cfa_stack}; 753 last; 754 }; 755 } 756 757 $self->{value} = ".cfi_$dir\t$$line" if ($dir); 758 759 $$line = ""; 760 } 761 762 return $ret; 763 } 764 sub out { 765 my $self = shift; 766 return ($elf ? $self->{value} : undef); 767 } 768} 769{ package directive; # pick up directives, which start with . 770 sub re { 771 my ($class, $line) = @_; 772 my $self = {}; 773 my $ret; 774 my $dir; 775 776 # chain-call to cfi_directive 777 $ret = cfi_directive->re($line) and return $ret; 778 779 if ($$line =~ /^\s*(\.\w+)/) { 780 bless $self,$class; 781 $dir = $1; 782 $ret = $self; 783 undef $self->{value}; 784 $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; 785 786 SWITCH: for ($dir) { 787 /\.global|\.globl|\.extern/ 788 && do { $globals{$$line} = $prefix . $$line; 789 $$line = $globals{$$line} if ($prefix); 790 last; 791 }; 792 /\.type/ && do { my ($sym,$type,$narg) = split(',',$$line); 793 if ($type eq "\@function") { 794 undef $current_function; 795 $current_function->{name} = $sym; 796 $current_function->{abi} = "svr4"; 797 $current_function->{narg} = $narg; 798 $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE"; 799 } elsif ($type eq "\@abi-omnipotent") { 800 undef $current_function; 801 $current_function->{name} = $sym; 802 $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE"; 803 } 804 $$line =~ s/\@abi\-omnipotent/\@function/; 805 $$line =~ s/\@function.*/\@function/; 806 last; 807 }; 808 /\.asciz/ && do { if ($$line =~ /^"(.*)"$/) { 809 $dir = ".byte"; 810 $$line = join(",",unpack("C*",$1),0); 811 } 812 last; 813 }; 814 /\.rva|\.long|\.quad/ 815 && do { $$line =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; 816 $$line =~ s/\.L/$decor/g; 817 last; 818 }; 819 } 820 821 if ($gas) { 822 $self->{value} = $dir . "\t" . $$line; 823 824 if ($dir =~ /\.extern/) { 825 $self->{value} = ""; # swallow extern 826 } elsif (!$elf && $dir =~ /\.type/) { 827 $self->{value} = ""; 828 $self->{value} = ".def\t" . ($globals{$1} or $1) . ";\t" . 829 (defined($globals{$1})?".scl 2;":".scl 3;") . 830 "\t.type 32;\t.endef" 831 if ($win64 && $$line =~ /([^,]+),\@function/); 832 } elsif (!$elf && $dir =~ /\.size/) { 833 $self->{value} = ""; 834 if (defined($current_function)) { 835 $self->{value} .= "${decor}SEH_end_$current_function->{name}:" 836 if ($win64 && $current_function->{abi} eq "svr4"); 837 undef $current_function; 838 } 839 } elsif (!$elf && $dir =~ /\.align/) { 840 $self->{value} = ".p2align\t" . (log($$line)/log(2)); 841 } elsif ($dir eq ".section") { 842 $current_segment=$$line; 843 if (!$elf && $current_segment eq ".init") { 844 if ($flavour eq "macosx") { $self->{value} = ".mod_init_func"; } 845 elsif ($flavour eq "mingw64") { $self->{value} = ".section\t.ctors"; } 846 } 847 } elsif ($dir =~ /\.(text|data)/) { 848 $current_segment=".$1"; 849 } elsif ($dir =~ /\.hidden/) { 850 if ($flavour eq "macosx") { $self->{value} = ".private_extern\t$prefix$$line"; } 851 elsif ($flavour eq "mingw64") { $self->{value} = ""; } 852 } elsif ($dir =~ /\.comm/) { 853 $self->{value} = "$dir\t$prefix$$line"; 854 $self->{value} =~ s|,([0-9]+),([0-9]+)$|",$1,".log($2)/log(2)|e if ($flavour eq "macosx"); 855 } 856 $$line = ""; 857 return $self; 858 } 859 860 # non-gas case or nasm/masm 861 SWITCH: for ($dir) { 862 /\.text/ && do { my $v=undef; 863 if ($nasm) { 864 $v="section .text code align=64\n"; 865 } else { 866 $v="$current_segment\tENDS\n" if ($current_segment); 867 $current_segment = ".text\$"; 868 $v.="$current_segment\tSEGMENT "; 869 $v.=$masm>=$masmref ? "ALIGN(256)" : "PAGE"; 870 $v.=" 'CODE'"; 871 } 872 $self->{value} = $v; 873 last; 874 }; 875 /\.data/ && do { my $v=undef; 876 if ($nasm) { 877 $v="section .data data align=8\n"; 878 } else { 879 $v="$current_segment\tENDS\n" if ($current_segment); 880 $current_segment = "_DATA"; 881 $v.="$current_segment\tSEGMENT"; 882 } 883 $self->{value} = $v; 884 last; 885 }; 886 /\.section/ && do { my $v=undef; 887 $$line =~ s/([^,]*).*/$1/; 888 $$line = ".CRT\$XCU" if ($$line eq ".init"); 889 if ($nasm) { 890 $v="section $$line"; 891 if ($$line=~/\.([px])data/) { 892 $v.=" rdata align="; 893 $v.=$1 eq "p"? 4 : 8; 894 } elsif ($$line=~/\.CRT\$/i) { 895 $v.=" rdata align=8"; 896 } 897 } else { 898 $v="$current_segment\tENDS\n" if ($current_segment); 899 $v.="$$line\tSEGMENT"; 900 if ($$line=~/\.([px])data/) { 901 $v.=" READONLY"; 902 $v.=" ALIGN(".($1 eq "p" ? 4 : 8).")" if ($masm>=$masmref); 903 } elsif ($$line=~/\.CRT\$/i) { 904 $v.=" READONLY "; 905 $v.=$masm>=$masmref ? "ALIGN(8)" : "DWORD"; 906 } 907 } 908 $current_segment = $$line; 909 $self->{value} = $v; 910 last; 911 }; 912 /\.extern/ && do { $self->{value} = "EXTERN\t".$$line; 913 $self->{value} .= ":NEAR" if ($masm); 914 last; 915 }; 916 /\.globl|.global/ 917 && do { $self->{value} = $masm?"PUBLIC":"global"; 918 $self->{value} .= "\t".$$line; 919 last; 920 }; 921 /\.size/ && do { if (defined($current_function)) { 922 undef $self->{value}; 923 if ($current_function->{abi} eq "svr4") { 924 $self->{value}="${decor}SEH_end_$current_function->{name}:"; 925 $self->{value}.=":\n" if($masm); 926 } 927 $self->{value}.="$current_function->{name}\tENDP" if($masm && $current_function->{name}); 928 undef $current_function; 929 } 930 last; 931 }; 932 /\.align/ && do { my $max = ($masm && $masm>=$masmref) ? 256 : 4096; 933 $self->{value} = "ALIGN\t".($$line>$max?$max:$$line); 934 last; 935 }; 936 /\.(value|long|rva|quad)/ 937 && do { my $sz = substr($1,0,1); 938 my @arr = split(/,\s*/,$$line); 939 my $last = pop(@arr); 940 my $conv = sub { my $var=shift; 941 $var=~s/^(0b[0-1]+)/oct($1)/eig; 942 $var=~s/^0x([0-9a-f]+)/0$1h/ig if ($masm); 943 if ($sz eq "D" && ($current_segment=~/.[px]data/ || $dir eq ".rva")) 944 { $var=~s/^([_a-z\$\@][_a-z0-9\$\@]*)/$nasm?"$1 wrt ..imagebase":"imagerel $1"/egi; } 945 $var; 946 }; 947 948 $sz =~ tr/bvlrq/BWDDQ/; 949 $self->{value} = "\tD$sz\t"; 950 for (@arr) { $self->{value} .= &$conv($_).","; } 951 $self->{value} .= &$conv($last); 952 last; 953 }; 954 /\.byte/ && do { my @str=split(/,\s*/,$$line); 955 map(s/(0b[0-1]+)/oct($1)/eig,@str); 956 map(s/0x([0-9a-f]+)/0$1h/ig,@str) if ($masm); 957 while ($#str>15) { 958 $self->{value}.="DB\t" 959 .join(",",@str[0..15])."\n"; 960 foreach (0..15) { shift @str; } 961 } 962 $self->{value}.="DB\t" 963 .join(",",@str) if (@str); 964 last; 965 }; 966 /\.comm/ && do { my @str=split(/,\s*/,$$line); 967 my $v=undef; 968 if ($nasm) { 969 $v.="common $prefix@str[0] @str[1]"; 970 } else { 971 $v="$current_segment\tENDS\n" if ($current_segment); 972 $current_segment = "_DATA"; 973 $v.="$current_segment\tSEGMENT\n"; 974 $v.="COMM @str[0]:DWORD:".@str[1]/4; 975 } 976 $self->{value} = $v; 977 last; 978 }; 979 } 980 $$line = ""; 981 } 982 983 $ret; 984 } 985 sub out { 986 my $self = shift; 987 $self->{value}; 988 } 989} 990 991# Upon initial x86_64 introduction SSE>2 extensions were not introduced 992# yet. In order not to be bothered by tracing exact assembler versions, 993# but at the same time to provide a bare security minimum of AES-NI, we 994# hard-code some instructions. Extensions past AES-NI on the other hand 995# are traced by examining assembler version in individual perlasm 996# modules... 997 998my %regrm = ( "%eax"=>0, "%ecx"=>1, "%edx"=>2, "%ebx"=>3, 999 "%esp"=>4, "%ebp"=>5, "%esi"=>6, "%edi"=>7 ); 1000 1001sub rex { 1002 my $opcode=shift; 1003 my ($dst,$src,$rex)=@_; 1004 1005 $rex|=0x04 if($dst>=8); 1006 $rex|=0x01 if($src>=8); 1007 push @$opcode,($rex|0x40) if ($rex); 1008} 1009 1010my $movq = sub { # elderly gas can't handle inter-register movq 1011 my $arg = shift; 1012 my @opcode=(0x66); 1013 if ($arg =~ /%xmm([0-9]+),\s*%r(\w+)/) { 1014 my ($src,$dst)=($1,$2); 1015 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } 1016 rex(\@opcode,$src,$dst,0x8); 1017 push @opcode,0x0f,0x7e; 1018 push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M 1019 @opcode; 1020 } elsif ($arg =~ /%r(\w+),\s*%xmm([0-9]+)/) { 1021 my ($src,$dst)=($2,$1); 1022 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } 1023 rex(\@opcode,$src,$dst,0x8); 1024 push @opcode,0x0f,0x6e; 1025 push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M 1026 @opcode; 1027 } else { 1028 (); 1029 } 1030}; 1031 1032my $pextrd = sub { 1033 if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*(%\w+)/) { 1034 my @opcode=(0x66); 1035 my $imm=$1; 1036 my $src=$2; 1037 my $dst=$3; 1038 if ($dst =~ /%r([0-9]+)d/) { $dst = $1; } 1039 elsif ($dst =~ /%e/) { $dst = $regrm{$dst}; } 1040 rex(\@opcode,$src,$dst); 1041 push @opcode,0x0f,0x3a,0x16; 1042 push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M 1043 push @opcode,$imm; 1044 @opcode; 1045 } else { 1046 (); 1047 } 1048}; 1049 1050my $pinsrd = sub { 1051 if (shift =~ /\$([0-9]+),\s*(%\w+),\s*%xmm([0-9]+)/) { 1052 my @opcode=(0x66); 1053 my $imm=$1; 1054 my $src=$2; 1055 my $dst=$3; 1056 if ($src =~ /%r([0-9]+)/) { $src = $1; } 1057 elsif ($src =~ /%e/) { $src = $regrm{$src}; } 1058 rex(\@opcode,$dst,$src); 1059 push @opcode,0x0f,0x3a,0x22; 1060 push @opcode,0xc0|(($dst&7)<<3)|($src&7); # ModR/M 1061 push @opcode,$imm; 1062 @opcode; 1063 } else { 1064 (); 1065 } 1066}; 1067 1068my $pshufb = sub { 1069 if (shift =~ /%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1070 my @opcode=(0x66); 1071 rex(\@opcode,$2,$1); 1072 push @opcode,0x0f,0x38,0x00; 1073 push @opcode,0xc0|($1&7)|(($2&7)<<3); # ModR/M 1074 @opcode; 1075 } else { 1076 (); 1077 } 1078}; 1079 1080my $palignr = sub { 1081 if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1082 my @opcode=(0x66); 1083 rex(\@opcode,$3,$2); 1084 push @opcode,0x0f,0x3a,0x0f; 1085 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M 1086 push @opcode,$1; 1087 @opcode; 1088 } else { 1089 (); 1090 } 1091}; 1092 1093my $pclmulqdq = sub { 1094 if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1095 my @opcode=(0x66); 1096 rex(\@opcode,$3,$2); 1097 push @opcode,0x0f,0x3a,0x44; 1098 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M 1099 my $c=$1; 1100 push @opcode,$c=~/^0/?oct($c):$c; 1101 @opcode; 1102 } else { 1103 (); 1104 } 1105}; 1106 1107my $rdrand = sub { 1108 if (shift =~ /%[er](\w+)/) { 1109 my @opcode=(); 1110 my $dst=$1; 1111 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } 1112 rex(\@opcode,0,$dst,8); 1113 push @opcode,0x0f,0xc7,0xf0|($dst&7); 1114 @opcode; 1115 } else { 1116 (); 1117 } 1118}; 1119 1120my $rdseed = sub { 1121 if (shift =~ /%[er](\w+)/) { 1122 my @opcode=(); 1123 my $dst=$1; 1124 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } 1125 rex(\@opcode,0,$dst,8); 1126 push @opcode,0x0f,0xc7,0xf8|($dst&7); 1127 @opcode; 1128 } else { 1129 (); 1130 } 1131}; 1132 1133# Not all AVX-capable assemblers recognize AMD XOP extension. Since we 1134# are using only two instructions hand-code them in order to be excused 1135# from chasing assembler versions... 1136 1137sub rxb { 1138 my $opcode=shift; 1139 my ($dst,$src1,$src2,$rxb)=@_; 1140 1141 $rxb|=0x7<<5; 1142 $rxb&=~(0x04<<5) if($dst>=8); 1143 $rxb&=~(0x01<<5) if($src1>=8); 1144 $rxb&=~(0x02<<5) if($src2>=8); 1145 push @$opcode,$rxb; 1146} 1147 1148my $vprotd = sub { 1149 if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1150 my @opcode=(0x8f); 1151 rxb(\@opcode,$3,$2,-1,0x08); 1152 push @opcode,0x78,0xc2; 1153 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M 1154 my $c=$1; 1155 push @opcode,$c=~/^0/?oct($c):$c; 1156 @opcode; 1157 } else { 1158 (); 1159 } 1160}; 1161 1162my $vprotq = sub { 1163 if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { 1164 my @opcode=(0x8f); 1165 rxb(\@opcode,$3,$2,-1,0x08); 1166 push @opcode,0x78,0xc3; 1167 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M 1168 my $c=$1; 1169 push @opcode,$c=~/^0/?oct($c):$c; 1170 @opcode; 1171 } else { 1172 (); 1173 } 1174}; 1175 1176# Intel Control-flow Enforcement Technology extension. All functions and 1177# indirect branch targets will have to start with this instruction... 1178 1179my $endbranch = sub { 1180 (0xf3,0x0f,0x1e,0xfa); 1181}; 1182 1183######################################################################## 1184 1185if ($nasm) { 1186 print <<___; 1187default rel 1188%define XMMWORD 1189%define YMMWORD 1190%define ZMMWORD 1191___ 1192} elsif ($masm) { 1193 print <<___; 1194OPTION DOTNAME 1195___ 1196} 1197while(defined(my $line=<>)) { 1198 1199 $line =~ s|\R$||; # Better chomp 1200 1201 $line =~ s|[#!].*$||; # get rid of asm-style comments... 1202 $line =~ s|/\*.*\*/||; # ... and C-style comments... 1203 $line =~ s|^\s+||; # ... and skip whitespaces in beginning 1204 $line =~ s|\s+$||; # ... and at the end 1205 1206 if (my $label=label->re(\$line)) { print $label->out(); } 1207 1208 if (my $directive=directive->re(\$line)) { 1209 printf "%s",$directive->out(); 1210 } elsif (my $opcode=opcode->re(\$line)) { 1211 my $asm = eval("\$".$opcode->mnemonic()); 1212 1213 if ((ref($asm) eq 'CODE') && scalar(my @bytes=&$asm($line))) { 1214 print $gas?".byte\t":"DB\t",join(',',@bytes),"\n"; 1215 next; 1216 } 1217 1218 my @args; 1219 ARGUMENT: while (1) { 1220 my $arg; 1221 1222 ($arg=register->re(\$line, $opcode))|| 1223 ($arg=const->re(\$line)) || 1224 ($arg=ea->re(\$line, $opcode)) || 1225 ($arg=expr->re(\$line, $opcode)) || 1226 last ARGUMENT; 1227 1228 push @args,$arg; 1229 1230 last ARGUMENT if ($line !~ /^,/); 1231 1232 $line =~ s/^,\s*//; 1233 } # ARGUMENT: 1234 1235 if ($#args>=0) { 1236 my $insn; 1237 my $sz=$opcode->size(); 1238 1239 if ($gas) { 1240 $insn = $opcode->out($#args>=1?$args[$#args]->size():$sz); 1241 @args = map($_->out($sz),@args); 1242 printf "\t%s\t%s",$insn,join(",",@args); 1243 } else { 1244 $insn = $opcode->out(); 1245 foreach (@args) { 1246 my $arg = $_->out(); 1247 # $insn.=$sz compensates for movq, pinsrw, ... 1248 if ($arg =~ /^xmm[0-9]+$/) { $insn.=$sz; $sz="x" if(!$sz); last; } 1249 if ($arg =~ /^ymm[0-9]+$/) { $insn.=$sz; $sz="y" if(!$sz); last; } 1250 if ($arg =~ /^zmm[0-9]+$/) { $insn.=$sz; $sz="z" if(!$sz); last; } 1251 if ($arg =~ /^mm[0-9]+$/) { $insn.=$sz; $sz="q" if(!$sz); last; } 1252 } 1253 @args = reverse(@args); 1254 undef $sz if ($nasm && $opcode->mnemonic() eq "lea"); 1255 printf "\t%s\t%s",$insn,join(",",map($_->out($sz),@args)); 1256 } 1257 } else { 1258 printf "\t%s",$opcode->out(); 1259 } 1260 } 1261 1262 print $line,"\n"; 1263} 1264 1265print "$cet_property" if ($cet_property); 1266print "\n$current_segment\tENDS\n" if ($current_segment && $masm); 1267print "END\n" if ($masm); 1268 1269close STDOUT or die "error closing STDOUT: $!;" 1270 1271 ################################################# 1272# Cross-reference x86_64 ABI "card" 1273# 1274# Unix Win64 1275# %rax * * 1276# %rbx - - 1277# %rcx #4 #1 1278# %rdx #3 #2 1279# %rsi #2 - 1280# %rdi #1 - 1281# %rbp - - 1282# %rsp - - 1283# %r8 #5 #3 1284# %r9 #6 #4 1285# %r10 * * 1286# %r11 * * 1287# %r12 - - 1288# %r13 - - 1289# %r14 - - 1290# %r15 - - 1291# 1292# (*) volatile register 1293# (-) preserved by callee 1294# (#) Nth argument, volatile 1295# 1296# In Unix terms top of stack is argument transfer area for arguments 1297# which could not be accommodated in registers. Or in other words 7th 1298# [integer] argument resides at 8(%rsp) upon function entry point. 1299# 128 bytes above %rsp constitute a "red zone" which is not touched 1300# by signal handlers and can be used as temporal storage without 1301# allocating a frame. 1302# 1303# In Win64 terms N*8 bytes on top of stack is argument transfer area, 1304# which belongs to/can be overwritten by callee. N is the number of 1305# arguments passed to callee, *but* not less than 4! This means that 1306# upon function entry point 5th argument resides at 40(%rsp), as well 1307# as that 32 bytes from 8(%rsp) can always be used as temporal 1308# storage [without allocating a frame]. One can actually argue that 1309# one can assume a "red zone" above stack pointer under Win64 as well. 1310# Point is that at apparently no occasion Windows kernel would alter 1311# the area above user stack pointer in true asynchronous manner... 1312# 1313# All the above means that if assembler programmer adheres to Unix 1314# register and stack layout, but disregards the "red zone" existence, 1315# it's possible to use following prologue and epilogue to "gear" from 1316# Unix to Win64 ABI in leaf functions with not more than 6 arguments. 1317# 1318# omnipotent_function: 1319# ifdef WIN64 1320# movq %rdi,8(%rsp) 1321# movq %rsi,16(%rsp) 1322# movq %rcx,%rdi ; if 1st argument is actually present 1323# movq %rdx,%rsi ; if 2nd argument is actually ... 1324# movq %r8,%rdx ; if 3rd argument is ... 1325# movq %r9,%rcx ; if 4th argument ... 1326# movq 40(%rsp),%r8 ; if 5th ... 1327# movq 48(%rsp),%r9 ; if 6th ... 1328# endif 1329# ... 1330# ifdef WIN64 1331# movq 8(%rsp),%rdi 1332# movq 16(%rsp),%rsi 1333# endif 1334# ret 1335# 1336 ################################################# 1337# Win64 SEH, Structured Exception Handling. 1338# 1339# Unlike on Unix systems(*) lack of Win64 stack unwinding information 1340# has undesired side-effect at run-time: if an exception is raised in 1341# assembler subroutine such as those in question (basically we're 1342# referring to segmentation violations caused by malformed input 1343# parameters), the application is briskly terminated without invoking 1344# any exception handlers, most notably without generating memory dump 1345# or any user notification whatsoever. This poses a problem. It's 1346# possible to address it by registering custom language-specific 1347# handler that would restore processor context to the state at 1348# subroutine entry point and return "exception is not handled, keep 1349# unwinding" code. Writing such handler can be a challenge... But it's 1350# doable, though requires certain coding convention. Consider following 1351# snippet: 1352# 1353# .type function,@function 1354# function: 1355# movq %rsp,%rax # copy rsp to volatile register 1356# pushq %r15 # save non-volatile registers 1357# pushq %rbx 1358# pushq %rbp 1359# movq %rsp,%r11 1360# subq %rdi,%r11 # prepare [variable] stack frame 1361# andq $-64,%r11 1362# movq %rax,0(%r11) # check for exceptions 1363# movq %r11,%rsp # allocate [variable] stack frame 1364# movq %rax,0(%rsp) # save original rsp value 1365# magic_point: 1366# ... 1367# movq 0(%rsp),%rcx # pull original rsp value 1368# movq -24(%rcx),%rbp # restore non-volatile registers 1369# movq -16(%rcx),%rbx 1370# movq -8(%rcx),%r15 1371# movq %rcx,%rsp # restore original rsp 1372# magic_epilogue: 1373# ret 1374# .size function,.-function 1375# 1376# The key is that up to magic_point copy of original rsp value remains 1377# in chosen volatile register and no non-volatile register, except for 1378# rsp, is modified. While past magic_point rsp remains constant till 1379# the very end of the function. In this case custom language-specific 1380# exception handler would look like this: 1381# 1382# EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame, 1383# CONTEXT *context,DISPATCHER_CONTEXT *disp) 1384# { ULONG64 *rsp = (ULONG64 *)context->Rax; 1385# ULONG64 rip = context->Rip; 1386# 1387# if (rip >= magic_point) 1388# { rsp = (ULONG64 *)context->Rsp; 1389# if (rip < magic_epilogue) 1390# { rsp = (ULONG64 *)rsp[0]; 1391# context->Rbp = rsp[-3]; 1392# context->Rbx = rsp[-2]; 1393# context->R15 = rsp[-1]; 1394# } 1395# } 1396# context->Rsp = (ULONG64)rsp; 1397# context->Rdi = rsp[1]; 1398# context->Rsi = rsp[2]; 1399# 1400# memcpy (disp->ContextRecord,context,sizeof(CONTEXT)); 1401# RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase, 1402# dips->ControlPc,disp->FunctionEntry,disp->ContextRecord, 1403# &disp->HandlerData,&disp->EstablisherFrame,NULL); 1404# return ExceptionContinueSearch; 1405# } 1406# 1407# It's appropriate to implement this handler in assembler, directly in 1408# function's module. In order to do that one has to know members' 1409# offsets in CONTEXT and DISPATCHER_CONTEXT structures and some constant 1410# values. Here they are: 1411# 1412# CONTEXT.Rax 120 1413# CONTEXT.Rcx 128 1414# CONTEXT.Rdx 136 1415# CONTEXT.Rbx 144 1416# CONTEXT.Rsp 152 1417# CONTEXT.Rbp 160 1418# CONTEXT.Rsi 168 1419# CONTEXT.Rdi 176 1420# CONTEXT.R8 184 1421# CONTEXT.R9 192 1422# CONTEXT.R10 200 1423# CONTEXT.R11 208 1424# CONTEXT.R12 216 1425# CONTEXT.R13 224 1426# CONTEXT.R14 232 1427# CONTEXT.R15 240 1428# CONTEXT.Rip 248 1429# CONTEXT.Xmm6 512 1430# sizeof(CONTEXT) 1232 1431# DISPATCHER_CONTEXT.ControlPc 0 1432# DISPATCHER_CONTEXT.ImageBase 8 1433# DISPATCHER_CONTEXT.FunctionEntry 16 1434# DISPATCHER_CONTEXT.EstablisherFrame 24 1435# DISPATCHER_CONTEXT.TargetIp 32 1436# DISPATCHER_CONTEXT.ContextRecord 40 1437# DISPATCHER_CONTEXT.LanguageHandler 48 1438# DISPATCHER_CONTEXT.HandlerData 56 1439# UNW_FLAG_NHANDLER 0 1440# ExceptionContinueSearch 1 1441# 1442# In order to tie the handler to the function one has to compose 1443# couple of structures: one for .xdata segment and one for .pdata. 1444# 1445# UNWIND_INFO structure for .xdata segment would be 1446# 1447# function_unwind_info: 1448# .byte 9,0,0,0 1449# .rva handler 1450# 1451# This structure designates exception handler for a function with 1452# zero-length prologue, no stack frame or frame register. 1453# 1454# To facilitate composing of .pdata structures, auto-generated "gear" 1455# prologue copies rsp value to rax and denotes next instruction with 1456# .LSEH_begin_{function_name} label. This essentially defines the SEH 1457# styling rule mentioned in the beginning. Position of this label is 1458# chosen in such manner that possible exceptions raised in the "gear" 1459# prologue would be accounted to caller and unwound from latter's frame. 1460# End of function is marked with respective .LSEH_end_{function_name} 1461# label. To summarize, .pdata segment would contain 1462# 1463# .rva .LSEH_begin_function 1464# .rva .LSEH_end_function 1465# .rva function_unwind_info 1466# 1467# Reference to function_unwind_info from .xdata segment is the anchor. 1468# In case you wonder why references are 32-bit .rvas and not 64-bit 1469# .quads. References put into these two segments are required to be 1470# *relative* to the base address of the current binary module, a.k.a. 1471# image base. No Win64 module, be it .exe or .dll, can be larger than 1472# 2GB and thus such relative references can be and are accommodated in 1473# 32 bits. 1474# 1475# Having reviewed the example function code, one can argue that "movq 1476# %rsp,%rax" above is redundant. It is not! Keep in mind that on Unix 1477# rax would contain an undefined value. If this "offends" you, use 1478# another register and refrain from modifying rax till magic_point is 1479# reached, i.e. as if it was a non-volatile register. If more registers 1480# are required prior [variable] frame setup is completed, note that 1481# nobody says that you can have only one "magic point." You can 1482# "liberate" non-volatile registers by denoting last stack off-load 1483# instruction and reflecting it in finer grade unwind logic in handler. 1484# After all, isn't it why it's called *language-specific* handler... 1485# 1486# SE handlers are also involved in unwinding stack when executable is 1487# profiled or debugged. Profiling implies additional limitations that 1488# are too subtle to discuss here. For now it's sufficient to say that 1489# in order to simplify handlers one should either a) offload original 1490# %rsp to stack (like discussed above); or b) if you have a register to 1491# spare for frame pointer, choose volatile one. 1492# 1493# (*) Note that we're talking about run-time, not debug-time. Lack of 1494# unwind information makes debugging hard on both Windows and 1495# Unix. "Unlike" refers to the fact that on Unix signal handler 1496# will always be invoked, core dumped and appropriate exit code 1497# returned to parent (for user notification). 1498