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boringssl/crypto/perlasm/x86_64-xlate.pl

1442 строки
44 KiB
Исходник Вина История 

  1. #! /usr/bin/env perl

  2. # Copyright 2005-2016 The OpenSSL Project Authors. All Rights Reserved.

  3. #

  4. # Licensed under the OpenSSL license (the "License").  You may not use

  5. # this file except in compliance with the License.  You can obtain a copy

  6. # in the file LICENSE in the source distribution or at

  7. # https://www.openssl.org/source/license.html

  8. 

  9. 

  10. # Ascetic x86_64 AT&T to MASM/NASM assembler translator by <appro>.

  11. #

  12. # Why AT&T to MASM and not vice versa? Several reasons. Because AT&T

  13. # format is way easier to parse. Because it's simpler to "gear" from

  14. # Unix ABI to Windows one [see cross-reference "card" at the end of

  15. # file]. Because Linux targets were available first...

  16. #

  17. # In addition the script also "distills" code suitable for GNU

  18. # assembler, so that it can be compiled with more rigid assemblers,

  19. # such as Solaris /usr/ccs/bin/as.

  20. #

  21. # This translator is not designed to convert *arbitrary* assembler

  22. # code from AT&T format to MASM one. It's designed to convert just

  23. # enough to provide for dual-ABI OpenSSL modules development...

  24. # There *are* limitations and you might have to modify your assembler

  25. # code or this script to achieve the desired result...

  26. #

  27. # Currently recognized limitations:

  28. #

  29. # - can't use multiple ops per line;

  30. #

  31. # Dual-ABI styling rules.

  32. #

  33. # 1. Adhere to Unix register and stack layout [see cross-reference

  34. #    ABI "card" at the end for explanation].

  35. # 2. Forget about "red zone," stick to more traditional blended

  36. #    stack frame allocation. If volatile storage is actually required

  37. #    that is. If not, just leave the stack as is.

  38. # 3. Functions tagged with ".type name,@function" get crafted with

  39. #    unified Win64 prologue and epilogue automatically. If you want

  40. #    to take care of ABI differences yourself, tag functions as

  41. #    ".type name,@abi-omnipotent" instead.

  42. # 4. To optimize the Win64 prologue you can specify number of input

  43. #    arguments as ".type name,@function,N." Keep in mind that if N is

  44. #    larger than 6, then you *have to* write "abi-omnipotent" code,

  45. #    because >6 cases can't be addressed with unified prologue.

  46. # 5. Name local labels as .L*, do *not* use dynamic labels such as 1:

  47. #    (sorry about latter).

  48. # 6. Don't use [or hand-code with .byte] "rep ret." "ret" mnemonic is

  49. #    required to identify the spots, where to inject Win64 epilogue!

  50. #    But on the pros, it's then prefixed with rep automatically:-)

  51. # 7. Stick to explicit ip-relative addressing. If you have to use

  52. #    GOTPCREL addressing, stick to mov symbol@GOTPCREL(%rip),%r??.

  53. #    Both are recognized and translated to proper Win64 addressing

  54. #    modes.

  55. #

  56. # 8. In order to provide for structured exception handling unified

  57. #    Win64 prologue copies %rsp value to %rax. For further details

  58. #    see SEH paragraph at the end.

  59. # 9. .init segment is allowed to contain calls to functions only.

  60. # a. If function accepts more than 4 arguments *and* >4th argument

  61. #    is declared as non 64-bit value, do clear its upper part.

  62. 

  63. 

  64. use strict;

  65. 

  66. my $flavour = shift;

  67. my $output  = shift;

  68. if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }

  69. 

  70. open STDOUT,">$output" || die "can't open $output: $!"

  71. 	if (defined($output));

  72. 

  73. my $gas=1;	$gas=0 if ($output =~ /\.asm$/);

  74. my $elf=1;	$elf=0 if (!$gas);

  75. my $win64=0;

  76. my $prefix="";

  77. my $decor=".L";

  78. 

  79. my $masmref=8 + 50727*2**-32;	# 8.00.50727 shipped with VS2005

  80. my $masm=0;

  81. my $PTR=" PTR";

  82. 

  83. my $nasmref=2.03;

  84. my $nasm=0;

  85. 

  86. if    ($flavour eq "mingw64")	{ $gas=1; $elf=0; $win64=1;

  87. 				  # TODO(davidben): Before supporting the

  88. 				  # mingw64 perlasm flavour, do away with this

  89. 				  # environment variable check.

  90.                                   die "mingw64 not supported";

  91. 				  $prefix=`echo __USER_LABEL_PREFIX__ | $ENV{CC} -E -P -`;

  92. 				  $prefix =~ s|\R$||; # Better chomp

  93. 				}

  94. elsif ($flavour eq "macosx")	{ $gas=1; $elf=0; $prefix="_"; $decor="L\$"; }

  95. elsif ($flavour eq "masm")	{ $gas=0; $elf=0; $masm=$masmref; $win64=1; $decor="\$L\$"; }

  96. elsif ($flavour eq "nasm")	{ $gas=0; $elf=0; $nasm=$nasmref; $win64=1; $decor="\$L\$"; $PTR=""; }

  97. elsif (!$gas)			{ die "unknown flavour $flavour"; }

  98. 

  99. my $current_segment;

  100. my $current_function;

  101. my %globals;

  102. 

  103. { package opcode;	# pick up opcodes

  104.     sub re {

  105. 	my	($class, $line) = @_;

  106. 	my	$self = {};

  107. 	my	$ret;

  108. 

  109. 	if ($$line =~ /^([a-z][a-z0-9]*)/i) {

  110. 	    bless $self,$class;

  111. 	    $self->{op} = $1;

  112. 	    $ret = $self;

  113. 	    $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;

  114. 

  115. 	    undef $self->{sz};

  116. 	    if ($self->{op} =~ /^(movz)x?([bw]).*/) {	# movz is pain...

  117. 		$self->{op} = $1;

  118. 		$self->{sz} = $2;

  119. 	    } elsif ($self->{op} =~ /call|jmp/) {

  120. 		$self->{sz} = "";

  121. 	    } elsif ($self->{op} =~ /^p/ && $' !~ /^(ush|op|insrw)/) { # SSEn

  122. 		$self->{sz} = "";

  123. 	    } elsif ($self->{op} =~ /^[vk]/) { # VEX or k* such as kmov

  124. 		$self->{sz} = "";

  125. 	    } elsif ($self->{op} =~ /mov[dq]/ && $$line =~ /%xmm/) {

  126. 		$self->{sz} = "";

  127. 	    } elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) {

  128. 		$self->{op} = $1;

  129. 		$self->{sz} = $2;

  130. 	    }

  131. 	}

  132. 	$ret;

  133.     }

  134.     sub size {

  135. 	my ($self, $sz) = @_;

  136. 	$self->{sz} = $sz if (defined($sz) && !defined($self->{sz}));

  137. 	$self->{sz};

  138.     }

  139.     sub out {

  140. 	my $self = shift;

  141. 	if ($gas) {

  142. 	    if ($self->{op} eq "movz") {	# movz is pain...

  143. 		sprintf "%s%s%s",$self->{op},$self->{sz},shift;

  144. 	    } elsif ($self->{op} =~ /^set/) {

  145. 		"$self->{op}";

  146. 	    } elsif ($self->{op} eq "ret") {

  147. 		my $epilogue = "";

  148. 		if ($win64 && $current_function->{abi} eq "svr4") {

  149. 		    $epilogue = "movq	8(%rsp),%rdi\n\t" .

  150. 				"movq	16(%rsp),%rsi\n\t";

  151. 		}

  152. 	    	$epilogue . ".byte	0xf3,0xc3";

  153. 	    } elsif ($self->{op} eq "call" && !$elf && $current_segment eq ".init") {

  154. 		".p2align\t3\n\t.quad";

  155. 	    } else {

  156. 		"$self->{op}$self->{sz}";

  157. 	    }

  158. 	} else {

  159. 	    $self->{op} =~ s/^movz/movzx/;

  160. 	    if ($self->{op} eq "ret") {

  161. 		$self->{op} = "";

  162. 		if ($win64 && $current_function->{abi} eq "svr4") {

  163. 		    $self->{op} = "mov	rdi,QWORD$PTR\[8+rsp\]\t;WIN64 epilogue\n\t".

  164. 				  "mov	rsi,QWORD$PTR\[16+rsp\]\n\t";

  165. 	    	}

  166. 		$self->{op} .= "DB\t0F3h,0C3h\t\t;repret";

  167. 	    } elsif ($self->{op} =~ /^(pop|push)f/) {

  168. 		$self->{op} .= $self->{sz};

  169. 	    } elsif ($self->{op} eq "call" && $current_segment eq ".CRT\$XCU") {

  170. 		$self->{op} = "\tDQ";

  171. 	    }

  172. 	    $self->{op};

  173. 	}

  174.     }

  175.     sub mnemonic {

  176. 	my ($self, $op) = @_;

  177. 	$self->{op}=$op if (defined($op));

  178. 	$self->{op};

  179.     }

  180. }

  181. { package const;	# pick up constants, which start with $

  182.     sub re {

  183. 	my	($class, $line) = @_;

  184. 	my	$self = {};

  185. 	my	$ret;

  186. 

  187. 	if ($$line =~ /^\$([^,]+)/) {

  188. 	    bless $self, $class;

  189. 	    $self->{value} = $1;

  190. 	    $ret = $self;

  191. 	    $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;

  192. 	}

  193. 	$ret;

  194.     }

  195.     sub out {

  196.     	my $self = shift;

  197. 

  198. 	$self->{value} =~ s/\b(0b[0-1]+)/oct($1)/eig;

  199. 	if ($gas) {

  200. 	    # Solaris /usr/ccs/bin/as can't handle multiplications

  201. 	    # in $self->{value}

  202. 	    my $value = $self->{value};

  203. 	    no warnings;    # oct might complain about overflow, ignore here...

  204. 	    $value =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi;

  205. 	    if ($value =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg) {

  206. 		$self->{value} = $value;

  207. 	    }

  208. 	    sprintf "\$%s",$self->{value};

  209. 	} else {

  210. 	    my $value = $self->{value};

  211. 	    $value =~ s/0x([0-9a-f]+)/0$1h/ig if ($masm);

  212. 	    sprintf "%s",$value;

  213. 	}

  214.     }

  215. }

  216. { package ea;		# pick up effective addresses: expr(%reg,%reg,scale)

  217. 

  218.     my %szmap = (	b=>"BYTE$PTR",    w=>"WORD$PTR",

  219. 			l=>"DWORD$PTR",   d=>"DWORD$PTR",

  220. 			q=>"QWORD$PTR",   o=>"OWORD$PTR",

  221. 			x=>"XMMWORD$PTR", y=>"YMMWORD$PTR",

  222. 			z=>"ZMMWORD$PTR" ) if (!$gas);

  223. 

  224.     sub re {

  225. 	my	($class, $line, $opcode) = @_;

  226. 	my	$self = {};

  227. 	my	$ret;

  228. 

  229. 	# optional * ----vvv--- appears in indirect jmp/call

  230. 	if ($$line =~ /^(\*?)([^\(,]*)\(([%\w,]+)\)((?:{[^}]+})*)/) {

  231. 	    bless $self, $class;

  232. 	    $self->{asterisk} = $1;

  233. 	    $self->{label} = $2;

  234. 	    ($self->{base},$self->{index},$self->{scale})=split(/,/,$3);

  235. 	    $self->{scale} = 1 if (!defined($self->{scale}));

  236. 	    $self->{opmask} = $4;

  237. 	    $ret = $self;

  238. 	    $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;

  239. 

  240. 	    if ($win64 && $self->{label} =~ s/\@GOTPCREL//) {

  241. 		die if ($opcode->mnemonic() ne "mov");

  242. 		$opcode->mnemonic("lea");

  243. 	    }

  244. 	    $self->{base}  =~ s/^%//;

  245. 	    $self->{index} =~ s/^%// if (defined($self->{index}));

  246. 	    $self->{opcode} = $opcode;

  247. 	}

  248. 	$ret;

  249.     }

  250.     sub size {}

  251.     sub out {

  252. 	my ($self, $sz) = @_;

  253. 

  254. 	$self->{label} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;

  255. 	$self->{label} =~ s/\.L/$decor/g;

  256. 

  257. 	# Silently convert all EAs to 64-bit. This is required for

  258. 	# elder GNU assembler and results in more compact code,

  259. 	# *but* most importantly AES module depends on this feature!

  260. 	$self->{index} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/;

  261. 	$self->{base}  =~ s/^[er](.?[0-9xpi])[d]?$/r\1/;

  262. 

  263. 	# Solaris /usr/ccs/bin/as can't handle multiplications

  264. 	# in $self->{label}...

  265. 	use integer;

  266. 	$self->{label} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi;

  267. 	$self->{label} =~ s/\b([0-9]+\s*[\*\/\%]\s*[0-9]+)\b/eval($1)/eg;

  268. 

  269. 	# Some assemblers insist on signed presentation of 32-bit

  270. 	# offsets, but sign extension is a tricky business in perl...

  271. 	if ((1<<31)<<1) {

  272. 	    $self->{label} =~ s/\b([0-9]+)\b/$1<<32>>32/eg;

  273. 	} else {

  274. 	    $self->{label} =~ s/\b([0-9]+)\b/$1>>0/eg;

  275. 	}

  276. 

  277. 	# if base register is %rbp or %r13, see if it's possible to

  278. 	# flip base and index registers [for better performance]

  279. 	if (!$self->{label} && $self->{index} && $self->{scale}==1 &&

  280. 	    $self->{base} =~ /(rbp|r13)/) {

  281. 		$self->{base} = $self->{index}; $self->{index} = $1;

  282. 	}

  283. 

  284. 	if ($gas) {

  285. 	    $self->{label} =~ s/^___imp_/__imp__/   if ($flavour eq "mingw64");

  286. 

  287. 	    if (defined($self->{index})) {

  288. 		sprintf "%s%s(%s,%%%s,%d)%s",

  289. 					$self->{asterisk},$self->{label},

  290. 					$self->{base}?"%$self->{base}":"",

  291. 					$self->{index},$self->{scale},

  292. 					$self->{opmask};

  293. 	    } else {

  294. 		sprintf "%s%s(%%%s)%s",	$self->{asterisk},$self->{label},

  295. 					$self->{base},$self->{opmask};

  296. 	    }

  297. 	} else {

  298. 	    $self->{label} =~ s/\./\$/g;

  299. 	    $self->{label} =~ s/(?<![\w\$\.])0x([0-9a-f]+)/0$1h/ig;

  300. 	    $self->{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/);

  301. 

  302. 	    my $mnemonic = $self->{opcode}->mnemonic();

  303. 	    ($self->{asterisk})				&& ($sz="q") ||

  304. 	    ($mnemonic =~ /^v?mov([qd])$/)		&& ($sz=$1)  ||

  305. 	    ($mnemonic =~ /^v?pinsr([qdwb])$/)		&& ($sz=$1)  ||

  306. 	    ($mnemonic =~ /^vpbroadcast([qdwb])$/)	&& ($sz=$1)  ||

  307. 	    ($mnemonic =~ /^v(?!perm)[a-z]+[fi]128$/)	&& ($sz="x");

  308. 

  309. 	    $self->{opmask}  =~ s/%(k[0-7])/$1/;

  310. 

  311. 	    if (defined($self->{index})) {

  312. 		sprintf "%s[%s%s*%d%s]%s",$szmap{$sz},

  313. 					$self->{label}?"$self->{label}+":"",

  314. 					$self->{index},$self->{scale},

  315. 					$self->{base}?"+$self->{base}":"",

  316. 					$self->{opmask};

  317. 	    } elsif ($self->{base} eq "rip") {

  318. 		sprintf "%s[%s]",$szmap{$sz},$self->{label};

  319. 	    } else {

  320. 		sprintf "%s[%s%s]%s",	$szmap{$sz},

  321. 					$self->{label}?"$self->{label}+":"",

  322. 					$self->{base},$self->{opmask};

  323. 	    }

  324. 	}

  325.     }

  326. }

  327. { package register;	# pick up registers, which start with %.

  328.     sub re {

  329. 	my	($class, $line, $opcode) = @_;

  330. 	my	$self = {};

  331. 	my	$ret;

  332. 

  333. 	# optional * ----vvv--- appears in indirect jmp/call

  334. 	if ($$line =~ /^(\*?)%(\w+)((?:{[^}]+})*)/) {

  335. 	    bless $self,$class;

  336. 	    $self->{asterisk} = $1;

  337. 	    $self->{value} = $2;

  338. 	    $self->{opmask} = $3;

  339. 	    $opcode->size($self->size());

  340. 	    $ret = $self;

  341. 	    $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;

  342. 	}

  343. 	$ret;

  344.     }

  345.     sub size {

  346. 	my	$self = shift;

  347. 	my	$ret;

  348. 

  349. 	if    ($self->{value} =~ /^r[\d]+b$/i)	{ $ret="b"; }

  350. 	elsif ($self->{value} =~ /^r[\d]+w$/i)	{ $ret="w"; }

  351. 	elsif ($self->{value} =~ /^r[\d]+d$/i)	{ $ret="l"; }

  352. 	elsif ($self->{value} =~ /^r[\w]+$/i)	{ $ret="q"; }

  353. 	elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; }

  354. 	elsif ($self->{value} =~ /^[\w]{2}l$/i)	{ $ret="b"; }

  355. 	elsif ($self->{value} =~ /^[\w]{2}$/i)	{ $ret="w"; }

  356. 	elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; }

  357. 

  358. 	$ret;

  359.     }

  360.     sub out {

  361.     	my $self = shift;

  362. 	if ($gas)	{ sprintf "%s%%%s%s",	$self->{asterisk},

  363. 						$self->{value},

  364. 						$self->{opmask}; }

  365. 	else		{ $self->{opmask} =~ s/%(k[0-7])/$1/;

  366. 			  $self->{value}.$self->{opmask}; }

  367.     }

  368. }

  369. { package label;	# pick up labels, which end with :

  370.     sub re {

  371. 	my	($class, $line) = @_;

  372. 	my	$self = {};

  373. 	my	$ret;

  374. 

  375. 	if ($$line =~ /(^[\.\w]+)\:/) {

  376. 	    bless $self,$class;

  377. 	    $self->{value} = $1;

  378. 	    $ret = $self;

  379. 	    $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;

  380. 

  381. 	    $self->{value} =~ s/^\.L/$decor/;

  382. 	}

  383. 	$ret;

  384.     }

  385.     sub out {

  386. 	my $self = shift;

  387. 

  388. 	if ($gas) {

  389. 	    my $func = ($globals{$self->{value}} or $self->{value}) . ":";

  390. 	    if ($win64	&& $current_function->{name} eq $self->{value}

  391. 			&& $current_function->{abi} eq "svr4") {

  392. 		$func .= "\n";

  393. 		$func .= "	movq	%rdi,8(%rsp)\n";

  394. 		$func .= "	movq	%rsi,16(%rsp)\n";

  395. 		$func .= "	movq	%rsp,%rax\n";

  396. 		$func .= "${decor}SEH_begin_$current_function->{name}:\n";

  397. 		my $narg = $current_function->{narg};

  398. 		$narg=6 if (!defined($narg));

  399. 		$func .= "	movq	%rcx,%rdi\n" if ($narg>0);

  400. 		$func .= "	movq	%rdx,%rsi\n" if ($narg>1);

  401. 		$func .= "	movq	%r8,%rdx\n"  if ($narg>2);

  402. 		$func .= "	movq	%r9,%rcx\n"  if ($narg>3);

  403. 		$func .= "	movq	40(%rsp),%r8\n" if ($narg>4);

  404. 		$func .= "	movq	48(%rsp),%r9\n" if ($narg>5);

  405. 	    }

  406. 	    $func;

  407. 	} elsif ($self->{value} ne "$current_function->{name}") {

  408. 	    # Make all labels in masm global.

  409. 	    $self->{value} .= ":" if ($masm);

  410. 	    $self->{value} . ":";

  411. 	} elsif ($win64 && $current_function->{abi} eq "svr4") {

  412. 	    my $func =	"$current_function->{name}" .

  413. 			($nasm ? ":" : "\tPROC $current_function->{scope}") .

  414. 			"\n";

  415. 	    $func .= "	mov	QWORD$PTR\[8+rsp\],rdi\t;WIN64 prologue\n";

  416. 	    $func .= "	mov	QWORD$PTR\[16+rsp\],rsi\n";

  417. 	    $func .= "	mov	rax,rsp\n";

  418. 	    $func .= "${decor}SEH_begin_$current_function->{name}:";

  419. 	    $func .= ":" if ($masm);

  420. 	    $func .= "\n";

  421. 	    my $narg = $current_function->{narg};

  422. 	    $narg=6 if (!defined($narg));

  423. 	    $func .= "	mov	rdi,rcx\n" if ($narg>0);

  424. 	    $func .= "	mov	rsi,rdx\n" if ($narg>1);

  425. 	    $func .= "	mov	rdx,r8\n"  if ($narg>2);

  426. 	    $func .= "	mov	rcx,r9\n"  if ($narg>3);

  427. 	    $func .= "	mov	r8,QWORD$PTR\[40+rsp\]\n" if ($narg>4);

  428. 	    $func .= "	mov	r9,QWORD$PTR\[48+rsp\]\n" if ($narg>5);

  429. 	    $func .= "\n";

  430. 	} else {

  431. 	   "$current_function->{name}".

  432. 			($nasm ? ":" : "\tPROC $current_function->{scope}");

  433. 	}

  434.     }

  435. }

  436. { package expr;		# pick up expressions

  437.     sub re {

  438. 	my	($class, $line, $opcode) = @_;

  439. 	my	$self = {};

  440. 	my	$ret;

  441. 

  442. 	if ($$line =~ /(^[^,]+)/) {

  443. 	    bless $self,$class;

  444. 	    $self->{value} = $1;

  445. 	    $ret = $self;

  446. 	    $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;

  447. 

  448. 	    $self->{value} =~ s/\@PLT// if (!$elf);

  449. 	    $self->{value} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;

  450. 	    $self->{value} =~ s/\.L/$decor/g;

  451. 	    $self->{opcode} = $opcode;

  452. 	}

  453. 	$ret;

  454.     }

  455.     sub out {

  456. 	my $self = shift;

  457. 	if ($nasm && $self->{opcode}->mnemonic()=~m/^j(?![re]cxz)/) {

  458. 	    "NEAR ".$self->{value};

  459. 	} else {

  460. 	    $self->{value};

  461. 	}

  462.     }

  463. }

  464. { package cfi_directive;

  465.     # CFI directives annotate instructions that are significant for

  466.     # stack unwinding procedure compliant with DWARF specification,

  467.     # see http://dwarfstd.org/. Besides naturally expected for this

  468.     # script platform-specific filtering function, this module adds

  469.     # three auxiliary synthetic directives not recognized by [GNU]

  470.     # assembler:

  471.     #

  472.     # - .cfi_push to annotate push instructions in prologue, which

  473.     #   translates to .cfi_adjust_cfa_offset (if needed) and

  474.     #   .cfi_offset;

  475.     # - .cfi_pop to annotate pop instructions in epilogue, which

  476.     #   translates to .cfi_adjust_cfa_offset (if needed) and

  477.     #   .cfi_restore;

  478.     # - [and most notably] .cfi_cfa_expression which encodes

  479.     #   DW_CFA_def_cfa_expression and passes it to .cfi_escape as

  480.     #   byte vector;

  481.     #

  482.     # CFA expressions were introduced in DWARF specification version

  483.     # 3 and describe how to deduce CFA, Canonical Frame Address. This

  484.     # becomes handy if your stack frame is variable and you can't

  485.     # spare register for [previous] frame pointer. Suggested directive

  486.     # syntax is made-up mix of DWARF operator suffixes [subset of]

  487.     # and references to registers with optional bias. Following example

  488.     # describes offloaded *original* stack pointer at specific offset

  489.     # from *current* stack pointer:

  490.     #

  491.     #   .cfi_cfa_expression     %rsp+40,deref,+8

  492.     #

  493.     # Final +8 has everything to do with the fact that CFA is defined

  494.     # as reference to top of caller's stack, and on x86_64 call to

  495.     # subroutine pushes 8-byte return address. In other words original

  496.     # stack pointer upon entry to a subroutine is 8 bytes off from CFA.

  497. 

  498.     # Below constants are taken from "DWARF Expressions" section of the

  499.     # DWARF specification, section is numbered 7.7 in versions 3 and 4.

  500.     my %DW_OP_simple = (	# no-arg operators, mapped directly

  501. 	deref	=> 0x06,	dup	=> 0x12,

  502. 	drop	=> 0x13,	over	=> 0x14,

  503. 	pick	=> 0x15,	swap	=> 0x16,

  504. 	rot	=> 0x17,	xderef	=> 0x18,

  505. 

  506. 	abs	=> 0x19,	and	=> 0x1a,

  507. 	div	=> 0x1b,	minus	=> 0x1c,

  508. 	mod	=> 0x1d,	mul	=> 0x1e,

  509. 	neg	=> 0x1f,	not	=> 0x20,

  510. 	or	=> 0x21,	plus	=> 0x22,

  511. 	shl	=> 0x24,	shr	=> 0x25,

  512. 	shra	=> 0x26,	xor	=> 0x27,

  513. 	);

  514. 

  515.     my %DW_OP_complex = (	# used in specific subroutines

  516. 	constu		=> 0x10,	# uleb128

  517. 	consts		=> 0x11,	# sleb128

  518. 	plus_uconst	=> 0x23,	# uleb128

  519. 	lit0 		=> 0x30,	# add 0-31 to opcode

  520. 	reg0		=> 0x50,	# add 0-31 to opcode

  521. 	breg0		=> 0x70,	# add 0-31 to opcole, sleb128

  522. 	regx		=> 0x90,	# uleb28

  523. 	fbreg		=> 0x91,	# sleb128

  524. 	bregx		=> 0x92,	# uleb128, sleb128

  525. 	piece		=> 0x93,	# uleb128

  526. 	);

  527. 

  528.     # Following constants are defined in x86_64 ABI supplement, for

  529.     # example avaiable at https://www.uclibc.org/docs/psABI-x86_64.pdf,

  530.     # see section 3.7 "Stack Unwind Algorithm".

  531.     my %DW_reg_idx = (

  532. 	"%rax"=>0,  "%rdx"=>1,  "%rcx"=>2,  "%rbx"=>3,

  533. 	"%rsi"=>4,  "%rdi"=>5,  "%rbp"=>6,  "%rsp"=>7,

  534. 	"%r8" =>8,  "%r9" =>9,  "%r10"=>10, "%r11"=>11,

  535. 	"%r12"=>12, "%r13"=>13, "%r14"=>14, "%r15"=>15

  536. 	);

  537. 

  538.     my ($cfa_reg, $cfa_rsp);

  539. 

  540.     # [us]leb128 format is variable-length integer representation base

  541.     # 2^128, with most significant bit of each byte being 0 denoting

  542.     # *last* most significat digit. See "Variable Length Data" in the

  543.     # DWARF specification, numbered 7.6 at least in versions 3 and 4.

  544.     sub sleb128 {

  545. 	use integer;	# get right shift extend sign

  546. 

  547. 	my $val = shift;

  548. 	my $sign = ($val < 0) ? -1 : 0;

  549. 	my @ret = ();

  550. 

  551. 	while(1) {

  552. 	    push @ret, $val&0x7f;

  553. 

  554. 	    # see if remaining bits are same and equal to most

  555. 	    # significant bit of the current digit, if so, it's

  556. 	    # last digit...

  557. 	    last if (($val>>6) == $sign);

  558. 

  559. 	    @ret[-1] |= 0x80;

  560. 	    $val >>= 7;

  561. 	}

  562. 

  563. 	return @ret;

  564.     }

  565.     sub uleb128 {

  566. 	my $val = shift;

  567. 	my @ret = ();

  568. 

  569. 	while(1) {

  570. 	    push @ret, $val&0x7f;

  571. 

  572. 	    # see if it's last significant digit...

  573. 	    last if (($val >>= 7) == 0);

  574. 

  575. 	    @ret[-1] |= 0x80;

  576. 	}

  577. 

  578. 	return @ret;

  579.     }

  580.     sub const {

  581. 	my $val = shift;

  582. 

  583. 	if ($val >= 0 && $val < 32) {

  584.             return ($DW_OP_complex{lit0}+$val);

  585. 	}

  586. 	return ($DW_OP_complex{consts}, sleb128($val));

  587.     }

  588.     sub reg {

  589. 	my $val = shift;

  590. 

  591. 	return if ($val !~ m/^(%r\w+)(?:([\+\-])((?:0x)?[0-9a-f]+))?/);

  592. 

  593. 	my $reg = $DW_reg_idx{$1};

  594. 	my $off = eval ("0 $2 $3");

  595. 

  596. 	return (($DW_OP_complex{breg0} + $reg), sleb128($off));

  597. 	# Yes, we use DW_OP_bregX+0 to push register value and not

  598. 	# DW_OP_regX, because latter would require even DW_OP_piece,

  599. 	# which would be a waste under the circumstances. If you have

  600. 	# to use DWP_OP_reg, use "regx:N"...

  601.     }

  602.     sub cfa_expression {

  603. 	my $line = shift;

  604. 	my @ret;

  605. 

  606. 	foreach my $token (split(/,\s*/,$line)) {

  607. 	    if ($token =~ /^%r/) {

  608. 		push @ret,reg($token);

  609. 	    } elsif ($token =~ /((?:0x)?[0-9a-f]+)\((%r\w+)\)/) {

  610. 		push @ret,reg("$2+$1");

  611. 	    } elsif ($token =~ /(\w+):(\-?(?:0x)?[0-9a-f]+)(U?)/i) {

  612. 		my $i = 1*eval($2);

  613. 		push @ret,$DW_OP_complex{$1}, ($3 ? uleb128($i) : sleb128($i));

  614. 	    } elsif (my $i = 1*eval($token) or $token eq "0") {

  615. 		if ($token =~ /^\+/) {

  616. 		    push @ret,$DW_OP_complex{plus_uconst},uleb128($i);

  617. 		} else {

  618. 		    push @ret,const($i);

  619. 		}

  620. 	    } else {

  621. 		push @ret,$DW_OP_simple{$token};

  622. 	    }

  623. 	}

  624. 

  625. 	# Finally we return DW_CFA_def_cfa_expression, 15, followed by

  626. 	# length of the expression and of course the expression itself.

  627. 	return (15,scalar(@ret),@ret);

  628.     }

  629.     sub re {

  630. 	my	($class, $line) = @_;

  631. 	my	$self = {};

  632. 	my	$ret;

  633. 

  634. 	if ($$line =~ s/^\s*\.cfi_(\w+)\s*//) {

  635. 	    bless $self,$class;

  636. 	    $ret = $self;

  637. 	    undef $self->{value};

  638. 	    my $dir = $1;

  639. 

  640. 	    SWITCH: for ($dir) {

  641. 	    # What is $cfa_rsp? Effectively it's difference between %rsp

  642. 	    # value and current CFA, Canonical Frame Address, which is

  643. 	    # why it starts with -8. Recall that CFA is top of caller's

  644. 	    # stack...

  645. 	    /startproc/	&& do {	($cfa_reg, $cfa_rsp) = ("%rsp", -8); last; };

  646. 	    /endproc/	&& do {	($cfa_reg, $cfa_rsp) = ("%rsp",  0); last; };

  647. 	    /def_cfa_register/

  648. 			&& do {	$cfa_reg = $$line; last; };

  649. 	    /def_cfa_offset/

  650. 			&& do {	$cfa_rsp = -1*eval($$line) if ($cfa_reg eq "%rsp");

  651. 				last;

  652. 			      };

  653. 	    /adjust_cfa_offset/

  654. 			&& do {	$cfa_rsp -= 1*eval($$line) if ($cfa_reg eq "%rsp");

  655. 				last;

  656. 			      };

  657. 	    /def_cfa/	&& do {	if ($$line =~ /(%r\w+)\s*,\s*(.+)/) {

  658. 				    $cfa_reg = $1;

  659. 				    $cfa_rsp = -1*eval($2) if ($cfa_reg eq "%rsp");

  660. 				}

  661. 				last;

  662. 			      };

  663. 	    /push/	&& do {	$dir = undef;

  664. 				$cfa_rsp -= 8;

  665. 				if ($cfa_reg eq "%rsp") {

  666. 				    $self->{value} = ".cfi_adjust_cfa_offset\t8\n";

  667. 				}

  668. 				$self->{value} .= ".cfi_offset\t$$line,$cfa_rsp";

  669. 				last;

  670. 			      };

  671. 	    /pop/	&& do {	$dir = undef;

  672. 				$cfa_rsp += 8;

  673. 				if ($cfa_reg eq "%rsp") {

  674. 				    $self->{value} = ".cfi_adjust_cfa_offset\t-8\n";

  675. 				}

  676. 				$self->{value} .= ".cfi_restore\t$$line";

  677. 				last;

  678. 			      };

  679. 	    /cfa_expression/

  680. 			&& do {	$dir = undef;

  681. 				$self->{value} = ".cfi_escape\t" .

  682. 					join(",", map(sprintf("0x%02x", $_),

  683. 						      cfa_expression($$line)));

  684. 				last;

  685. 			      };

  686. 	    }

  687. 

  688. 	    $self->{value} = ".cfi_$dir\t$$line" if ($dir);

  689. 

  690. 	    $$line = "";

  691. 	}

  692. 

  693. 	return $ret;

  694.     }

  695.     sub out {

  696. 	my $self = shift;

  697. 	return ($elf ? $self->{value} : undef);

  698.     }

  699. }

  700. { package directive;	# pick up directives, which start with .

  701.     sub re {

  702. 	my	($class, $line) = @_;

  703. 	my	$self = {};

  704. 	my	$ret;

  705. 	my	$dir;

  706. 

  707. 	# chain-call to cfi_directive

  708. 	$ret = cfi_directive->re($line) and return $ret;

  709. 

  710. 	if ($$line =~ /^\s*(\.\w+)/) {

  711. 	    bless $self,$class;

  712. 	    $dir = $1;

  713. 	    $ret = $self;

  714. 	    undef $self->{value};

  715. 	    $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;

  716. 

  717. 	    SWITCH: for ($dir) {

  718. 		/\.global|\.globl|\.extern/

  719. 			    && do { $globals{$$line} = $prefix . $$line;

  720. 				    $$line = $globals{$$line} if ($prefix);

  721. 				    last;

  722. 				  };

  723. 		/\.type/    && do { my ($sym,$type,$narg) = split(',',$$line);

  724. 				    if ($type eq "\@function") {

  725. 					undef $current_function;

  726. 					$current_function->{name} = $sym;

  727. 					$current_function->{abi}  = "svr4";

  728. 					$current_function->{narg} = $narg;

  729. 					$current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE";

  730. 				    } elsif ($type eq "\@abi-omnipotent") {

  731. 					undef $current_function;

  732. 					$current_function->{name} = $sym;

  733. 					$current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE";

  734. 				    }

  735. 				    $$line =~ s/\@abi\-omnipotent/\@function/;

  736. 				    $$line =~ s/\@function.*/\@function/;

  737. 				    last;

  738. 				  };

  739. 		/\.asciz/   && do { if ($$line =~ /^"(.*)"$/) {

  740. 					$dir  = ".byte";

  741. 					$$line = join(",",unpack("C*",$1),0);

  742. 				    }

  743. 				    last;

  744. 				  };

  745. 		/\.rva|\.long|\.quad/

  746. 			    && do { $$line =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;

  747. 				    $$line =~ s/\.L/$decor/g;

  748. 				    last;

  749. 				  };

  750. 	    }

  751. 

  752. 	    if ($gas) {

  753. 		$self->{value} = $dir . "\t" . $$line;

  754. 

  755. 		if ($dir =~ /\.extern/) {

  756. 		    if ($flavour eq "elf") {

  757. 			$self->{value} .= "\n.hidden $$line";

  758. 		    } else {

  759. 			$self->{value} = "";

  760. 		    }

  761. 		} elsif (!$elf && $dir =~ /\.type/) {

  762. 		    $self->{value} = "";

  763. 		    $self->{value} = ".def\t" . ($globals{$1} or $1) . ";\t" .

  764. 				(defined($globals{$1})?".scl 2;":".scl 3;") .

  765. 				"\t.type 32;\t.endef"

  766. 				if ($win64 && $$line =~ /([^,]+),\@function/);

  767. 		} elsif (!$elf && $dir =~ /\.size/) {

  768. 		    $self->{value} = "";

  769. 		    if (defined($current_function)) {

  770. 			$self->{value} .= "${decor}SEH_end_$current_function->{name}:"

  771. 				if ($win64 && $current_function->{abi} eq "svr4");

  772. 			undef $current_function;

  773. 		    }

  774. 		} elsif (!$elf && $dir =~ /\.align/) {

  775. 		    $self->{value} = ".p2align\t" . (log($$line)/log(2));

  776. 		} elsif ($dir eq ".section") {

  777. 		    $current_segment=$$line;

  778. 		    if (!$elf && $current_segment eq ".init") {

  779. 			if	($flavour eq "macosx")	{ $self->{value} = ".mod_init_func"; }

  780. 			elsif	($flavour eq "mingw64")	{ $self->{value} = ".section\t.ctors"; }

  781. 		    }

  782. 		} elsif ($dir =~ /\.(text|data)/) {

  783. 		    $current_segment=".$1";

  784. 		} elsif ($dir =~ /\.global|\.globl|\.extern/) {

  785. 		    if ($flavour eq "macosx") {

  786. 		        $self->{value} .= "\n.private_extern $$line";

  787. 		    } else {

  788. 		        $self->{value} .= "\n.hidden $$line";

  789. 		    }

  790. 		} elsif ($dir =~ /\.hidden/) {

  791. 		    if    ($flavour eq "macosx")  { $self->{value} = ".private_extern\t$prefix$$line"; }

  792. 		    elsif ($flavour eq "mingw64") { $self->{value} = ""; }

  793. 		} elsif ($dir =~ /\.comm/) {

  794. 		    $self->{value} = "$dir\t$prefix$$line";

  795. 		    $self->{value} =~ s|,([0-9]+),([0-9]+)$|",$1,".log($2)/log(2)|e if ($flavour eq "macosx");

  796. 		}

  797. 		$$line = "";

  798. 		return $self;

  799. 	    }

  800. 

  801. 	    # non-gas case or nasm/masm

  802. 	    SWITCH: for ($dir) {

  803. 		/\.text/    && do { my $v=undef;

  804. 				    if ($nasm) {

  805. 					$v="section	.text code align=64\n";

  806. 				    } else {

  807. 					$v="$current_segment\tENDS\n" if ($current_segment);

  808. 					$current_segment = ".text\$";

  809. 					$v.="$current_segment\tSEGMENT ";

  810. 					$v.=$masm>=$masmref ? "ALIGN(256)" : "PAGE";

  811. 					$v.=" 'CODE'";

  812. 				    }

  813. 				    $self->{value} = $v;

  814. 				    last;

  815. 				  };

  816. 		/\.data/    && do { my $v=undef;

  817. 				    if ($nasm) {

  818. 					$v="section	.data data align=8\n";

  819. 				    } else {

  820. 					$v="$current_segment\tENDS\n" if ($current_segment);

  821. 					$current_segment = "_DATA";

  822. 					$v.="$current_segment\tSEGMENT";

  823. 				    }

  824. 				    $self->{value} = $v;

  825. 				    last;

  826. 				  };

  827. 		/\.section/ && do { my $v=undef;

  828. 				    $$line =~ s/([^,]*).*/$1/;

  829. 				    $$line = ".CRT\$XCU" if ($$line eq ".init");

  830. 				    if ($nasm) {

  831. 					$v="section	$$line";

  832. 					if ($$line=~/\.([px])data/) {

  833. 					    $v.=" rdata align=";

  834. 					    $v.=$1 eq "p"? 4 : 8;

  835. 					} elsif ($$line=~/\.CRT\$/i) {

  836. 					    $v.=" rdata align=8";

  837. 					}

  838. 				    } else {

  839. 					$v="$current_segment\tENDS\n" if ($current_segment);

  840. 					$v.="$$line\tSEGMENT";

  841. 					if ($$line=~/\.([px])data/) {

  842. 					    $v.=" READONLY";

  843. 					    $v.=" ALIGN(".($1 eq "p" ? 4 : 8).")" if ($masm>=$masmref);

  844. 					} elsif ($$line=~/\.CRT\$/i) {

  845. 					    $v.=" READONLY ";

  846. 					    $v.=$masm>=$masmref ? "ALIGN(8)" : "DWORD";

  847. 					}

  848. 				    }

  849. 				    $current_segment = $$line;

  850. 				    $self->{value} = $v;

  851. 				    last;

  852. 				  };

  853. 		/\.extern/  && do { $self->{value}  = "EXTERN\t".$$line;

  854. 				    $self->{value} .= ":NEAR" if ($masm);

  855. 				    last;

  856. 				  };

  857. 		/\.globl|.global/

  858. 			    && do { $self->{value}  = $masm?"PUBLIC":"global";

  859. 				    $self->{value} .= "\t".$$line;

  860. 				    last;

  861. 				  };

  862. 		/\.size/    && do { if (defined($current_function)) {

  863. 					undef $self->{value};

  864. 					if ($current_function->{abi} eq "svr4") {

  865. 					    $self->{value}="${decor}SEH_end_$current_function->{name}:";

  866. 					    $self->{value}.=":\n" if($masm);

  867. 					}

  868. 					$self->{value}.="$current_function->{name}\tENDP" if($masm && $current_function->{name});

  869. 					undef $current_function;

  870. 				    }

  871. 				    last;

  872. 				  };

  873. 		/\.align/   && do { my $max = ($masm && $masm>=$masmref) ? 256 : 4096;

  874. 				    $self->{value} = "ALIGN\t".($$line>$max?$max:$$line);

  875. 				    last;

  876. 				  };

  877. 		/\.(value|long|rva|quad)/

  878. 			    && do { my $sz  = substr($1,0,1);

  879. 				    my @arr = split(/,\s*/,$$line);

  880. 				    my $last = pop(@arr);

  881. 				    my $conv = sub  {	my $var=shift;

  882. 							$var=~s/^(0b[0-1]+)/oct($1)/eig;

  883. 							$var=~s/^0x([0-9a-f]+)/0$1h/ig if ($masm);

  884. 							if ($sz eq "D" && ($current_segment=~/.[px]data/ || $dir eq ".rva"))

  885. 							{ $var=~s/([_a-z\$\@][_a-z0-9\$\@]*)/$nasm?"$1 wrt ..imagebase":"imagerel $1"/egi; }

  886. 							$var;

  887. 						    };

  888. 

  889. 				    $sz =~ tr/bvlrq/BWDDQ/;

  890. 				    $self->{value} = "\tD$sz\t";

  891. 				    for (@arr) { $self->{value} .= &$conv($_).","; }

  892. 				    $self->{value} .= &$conv($last);

  893. 				    last;

  894. 				  };

  895. 		/\.byte/    && do { my @str=split(/,\s*/,$$line);

  896. 				    map(s/(0b[0-1]+)/oct($1)/eig,@str);

  897. 				    map(s/0x([0-9a-f]+)/0$1h/ig,@str) if ($masm);

  898. 				    while ($#str>15) {

  899. 					$self->{value}.="DB\t"

  900. 						.join(",",@str[0..15])."\n";

  901. 					foreach (0..15) { shift @str; }

  902. 				    }

  903. 				    $self->{value}.="DB\t"

  904. 						.join(",",@str) if (@str);

  905. 				    last;

  906. 				  };

  907. 		/\.comm/    && do { my @str=split(/,\s*/,$$line);

  908. 				    my $v=undef;

  909. 				    if ($nasm) {

  910. 					$v.="common	$prefix@str[0] @str[1]";

  911. 				    } else {

  912. 					$v="$current_segment\tENDS\n" if ($current_segment);

  913. 					$current_segment = "_DATA";

  914. 					$v.="$current_segment\tSEGMENT\n";

  915. 					$v.="COMM	@str[0]:DWORD:".@str[1]/4;

  916. 				    }

  917. 				    $self->{value} = $v;

  918. 				    last;

  919. 				  };

  920. 	    }

  921. 	    $$line = "";

  922. 	}

  923. 

  924. 	$ret;

  925.     }

  926.     sub out {

  927. 	my $self = shift;

  928. 	$self->{value};

  929.     }

  930. }

  931. 

  932. # Upon initial x86_64 introduction SSE>2 extensions were not introduced

  933. # yet. In order not to be bothered by tracing exact assembler versions,

  934. # but at the same time to provide a bare security minimum of AES-NI, we

  935. # hard-code some instructions. Extensions past AES-NI on the other hand

  936. # are traced by examining assembler version in individual perlasm

  937. # modules...

  938. 

  939. my %regrm = (	"%eax"=>0, "%ecx"=>1, "%edx"=>2, "%ebx"=>3,

  940. 		"%esp"=>4, "%ebp"=>5, "%esi"=>6, "%edi"=>7	);

  941. 

  942. sub rex {

  943.  my $opcode=shift;

  944.  my ($dst,$src,$rex)=@_;

  945. 

  946.    $rex|=0x04 if($dst>=8);

  947.    $rex|=0x01 if($src>=8);

  948.    push @$opcode,($rex|0x40) if ($rex);

  949. }

  950. 

  951. my $movq = sub {	# elderly gas can't handle inter-register movq

  952.   my $arg = shift;

  953.   my @opcode=(0x66);

  954.     if ($arg =~ /%xmm([0-9]+),\s*%r(\w+)/) {

  955. 	my ($src,$dst)=($1,$2);

  956. 	if ($dst !~ /[0-9]+/)	{ $dst = $regrm{"%e$dst"}; }

  957. 	rex(\@opcode,$src,$dst,0x8);

  958. 	push @opcode,0x0f,0x7e;

  959. 	push @opcode,0xc0|(($src&7)<<3)|($dst&7);	# ModR/M

  960. 	@opcode;

  961.     } elsif ($arg =~ /%r(\w+),\s*%xmm([0-9]+)/) {

  962. 	my ($src,$dst)=($2,$1);

  963. 	if ($dst !~ /[0-9]+/)	{ $dst = $regrm{"%e$dst"}; }

  964. 	rex(\@opcode,$src,$dst,0x8);

  965. 	push @opcode,0x0f,0x6e;

  966. 	push @opcode,0xc0|(($src&7)<<3)|($dst&7);	# ModR/M

  967. 	@opcode;

  968.     } else {

  969. 	();

  970.     }

  971. };

  972. 

  973. my $pextrd = sub {

  974.     if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*(%\w+)/) {

  975.       my @opcode=(0x66);

  976. 	my $imm=$1;

  977. 	my $src=$2;

  978. 	my $dst=$3;

  979. 	if ($dst =~ /%r([0-9]+)d/)	{ $dst = $1; }

  980. 	elsif ($dst =~ /%e/)		{ $dst = $regrm{$dst}; }

  981. 	rex(\@opcode,$src,$dst);

  982. 	push @opcode,0x0f,0x3a,0x16;

  983. 	push @opcode,0xc0|(($src&7)<<3)|($dst&7);	# ModR/M

  984. 	push @opcode,$imm;

  985. 	@opcode;

  986.     } else {

  987. 	();

  988.     }

  989. };

  990. 

  991. my $pinsrd = sub {

  992.     if (shift =~ /\$([0-9]+),\s*(%\w+),\s*%xmm([0-9]+)/) {

  993.       my @opcode=(0x66);

  994. 	my $imm=$1;

  995. 	my $src=$2;

  996. 	my $dst=$3;

  997. 	if ($src =~ /%r([0-9]+)/)	{ $src = $1; }

  998. 	elsif ($src =~ /%e/)		{ $src = $regrm{$src}; }

  999. 	rex(\@opcode,$dst,$src);

  1000. 	push @opcode,0x0f,0x3a,0x22;

  1001. 	push @opcode,0xc0|(($dst&7)<<3)|($src&7);	# ModR/M

  1002. 	push @opcode,$imm;

  1003. 	@opcode;

  1004.     } else {

  1005. 	();

  1006.     }

  1007. };

  1008. 

  1009. my $pshufb = sub {

  1010.     if (shift =~ /%xmm([0-9]+),\s*%xmm([0-9]+)/) {

  1011.       my @opcode=(0x66);

  1012. 	rex(\@opcode,$2,$1);

  1013. 	push @opcode,0x0f,0x38,0x00;

  1014. 	push @opcode,0xc0|($1&7)|(($2&7)<<3);		# ModR/M

  1015. 	@opcode;

  1016.     } else {

  1017. 	();

  1018.     }

  1019. };

  1020. 

  1021. my $palignr = sub {

  1022.     if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {

  1023.       my @opcode=(0x66);

  1024. 	rex(\@opcode,$3,$2);

  1025. 	push @opcode,0x0f,0x3a,0x0f;

  1026. 	push @opcode,0xc0|($2&7)|(($3&7)<<3);		# ModR/M

  1027. 	push @opcode,$1;

  1028. 	@opcode;

  1029.     } else {

  1030. 	();

  1031.     }

  1032. };

  1033. 

  1034. my $pclmulqdq = sub {

  1035.     if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {

  1036.       my @opcode=(0x66);

  1037. 	rex(\@opcode,$3,$2);

  1038. 	push @opcode,0x0f,0x3a,0x44;

  1039. 	push @opcode,0xc0|($2&7)|(($3&7)<<3);		# ModR/M

  1040. 	my $c=$1;

  1041. 	push @opcode,$c=~/^0/?oct($c):$c;

  1042. 	@opcode;

  1043.     } else {

  1044. 	();

  1045.     }

  1046. };

  1047. 

  1048. my $rdrand = sub {

  1049.     if (shift =~ /%[er](\w+)/) {

  1050.       my @opcode=();

  1051.       my $dst=$1;

  1052. 	if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; }

  1053. 	rex(\@opcode,0,$dst,8);

  1054. 	push @opcode,0x0f,0xc7,0xf0|($dst&7);

  1055. 	@opcode;

  1056.     } else {

  1057. 	();

  1058.     }

  1059. };

  1060. 

  1061. my $rdseed = sub {

  1062.     if (shift =~ /%[er](\w+)/) {

  1063.       my @opcode=();

  1064.       my $dst=$1;

  1065. 	if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; }

  1066. 	rex(\@opcode,0,$dst,8);

  1067. 	push @opcode,0x0f,0xc7,0xf8|($dst&7);

  1068. 	@opcode;

  1069.     } else {

  1070. 	();

  1071.     }

  1072. };

  1073. 

  1074. # Not all AVX-capable assemblers recognize AMD XOP extension. Since we

  1075. # are using only two instructions hand-code them in order to be excused

  1076. # from chasing assembler versions...

  1077. 

  1078. sub rxb {

  1079.  my $opcode=shift;

  1080.  my ($dst,$src1,$src2,$rxb)=@_;

  1081. 

  1082.    $rxb|=0x7<<5;

  1083.    $rxb&=~(0x04<<5) if($dst>=8);

  1084.    $rxb&=~(0x01<<5) if($src1>=8);

  1085.    $rxb&=~(0x02<<5) if($src2>=8);

  1086.    push @$opcode,$rxb;

  1087. }

  1088. 

  1089. my $vprotd = sub {

  1090.     if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {

  1091.       my @opcode=(0x8f);

  1092. 	rxb(\@opcode,$3,$2,-1,0x08);

  1093. 	push @opcode,0x78,0xc2;

  1094. 	push @opcode,0xc0|($2&7)|(($3&7)<<3);		# ModR/M

  1095. 	my $c=$1;

  1096. 	push @opcode,$c=~/^0/?oct($c):$c;

  1097. 	@opcode;

  1098.     } else {

  1099. 	();

  1100.     }

  1101. };

  1102. 

  1103. my $vprotq = sub {

  1104.     if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {

  1105.       my @opcode=(0x8f);

  1106. 	rxb(\@opcode,$3,$2,-1,0x08);

  1107. 	push @opcode,0x78,0xc3;

  1108. 	push @opcode,0xc0|($2&7)|(($3&7)<<3);		# ModR/M

  1109. 	my $c=$1;

  1110. 	push @opcode,$c=~/^0/?oct($c):$c;

  1111. 	@opcode;

  1112.     } else {

  1113. 	();

  1114.     }

  1115. };

  1116. 

  1117. # Intel Control-flow Enforcement Technology extension. All functions and

  1118. # indirect branch targets will have to start with this instruction...

  1119. 

  1120. my $endbranch = sub {

  1121.     (0xf3,0x0f,0x1e,0xfa);

  1122. };

  1123. 

  1124. ########################################################################

  1125. 

  1126. if ($nasm) {

  1127.     print <<___;

  1128. default	rel

  1129. %define XMMWORD

  1130. %define YMMWORD

  1131. %define ZMMWORD

  1132. ___

  1133. } elsif ($masm) {

  1134.     print <<___;

  1135. OPTION	DOTNAME

  1136. ___

  1137. }

  1138. print STDOUT "#if defined(__x86_64__) && !defined(OPENSSL_NO_ASM)\n" if ($gas);

  1139. 

  1140. while(defined(my $line=<>)) {

  1141. 

  1142.     $line =~ s|\R$||;           # Better chomp

  1143. 

  1144.     $line =~ s|[#!].*$||;	# get rid of asm-style comments...

  1145.     $line =~ s|/\*.*\*/||;	# ... and C-style comments...

  1146.     $line =~ s|^\s+||;		# ... and skip white spaces in beginning

  1147.     $line =~ s|\s+$||;		# ... and at the end

  1148. 

  1149.     if (my $label=label->re(\$line))	{ print $label->out(); }

  1150. 

  1151.     if (my $directive=directive->re(\$line)) {

  1152. 	printf "%s",$directive->out();

  1153.     } elsif (my $opcode=opcode->re(\$line)) {

  1154. 	my $asm = eval("\$".$opcode->mnemonic());

  1155. 

  1156. 	if ((ref($asm) eq 'CODE') && scalar(my @bytes=&$asm($line))) {

  1157. 	    print $gas?".byte\t":"DB\t",join(',',@bytes),"\n";

  1158. 	    next;

  1159. 	}

  1160. 

  1161. 	my @args;

  1162. 	ARGUMENT: while (1) {

  1163. 	    my $arg;

  1164. 

  1165. 	    ($arg=register->re(\$line, $opcode))||

  1166. 	    ($arg=const->re(\$line))		||

  1167. 	    ($arg=ea->re(\$line, $opcode))	||

  1168. 	    ($arg=expr->re(\$line, $opcode))	||

  1169. 	    last ARGUMENT;

  1170. 

  1171. 	    push @args,$arg;

  1172. 

  1173. 	    last ARGUMENT if ($line !~ /^,/);

  1174. 

  1175. 	    $line =~ s/^,\s*//;

  1176. 	} # ARGUMENT:

  1177. 

  1178. 	if ($#args>=0) {

  1179. 	    my $insn;

  1180. 	    my $sz=$opcode->size();

  1181. 

  1182. 	    if ($gas) {

  1183. 		$insn = $opcode->out($#args>=1?$args[$#args]->size():$sz);

  1184. 		@args = map($_->out($sz),@args);

  1185. 		printf "\t%s\t%s",$insn,join(",",@args);

  1186. 	    } else {

  1187. 		$insn = $opcode->out();

  1188. 		foreach (@args) {

  1189. 		    my $arg = $_->out();

  1190. 		    # $insn.=$sz compensates for movq, pinsrw, ...

  1191. 		    if ($arg =~ /^xmm[0-9]+$/) { $insn.=$sz; $sz="x" if(!$sz); last; }

  1192. 		    if ($arg =~ /^ymm[0-9]+$/) { $insn.=$sz; $sz="y" if(!$sz); last; }

  1193. 		    if ($arg =~ /^zmm[0-9]+$/) { $insn.=$sz; $sz="z" if(!$sz); last; }

  1194. 		    if ($arg =~ /^mm[0-9]+$/)  { $insn.=$sz; $sz="q" if(!$sz); last; }

  1195. 		}

  1196. 		@args = reverse(@args);

  1197. 		undef $sz if ($nasm && $opcode->mnemonic() eq "lea");

  1198. 		printf "\t%s\t%s",$insn,join(",",map($_->out($sz),@args));

  1199. 	    }

  1200. 	} else {

  1201. 	    printf "\t%s",$opcode->out();

  1202. 	}

  1203.     }

  1204. 

  1205.     print $line,"\n";

  1206. }

  1207. 

  1208. print "\n$current_segment\tENDS\n"	if ($current_segment && $masm);

  1209. print "END\n"				if ($masm);

  1210. print "#endif\n"			if ($gas);

  1211. 

  1212. 

  1213. close STDOUT;

  1214. 

  1215. #################################################

  1216. # Cross-reference x86_64 ABI "card"

  1217. #

  1218. # 		Unix		Win64

  1219. # %rax		*		*

  1220. # %rbx		-		-

  1221. # %rcx		#4		#1

  1222. # %rdx		#3		#2

  1223. # %rsi		#2		-

  1224. # %rdi		#1		-

  1225. # %rbp		-		-

  1226. # %rsp		-		-

  1227. # %r8		#5		#3

  1228. # %r9		#6		#4

  1229. # %r10		*		*

  1230. # %r11		*		*

  1231. # %r12		-		-

  1232. # %r13		-		-

  1233. # %r14		-		-

  1234. # %r15		-		-

  1235. #

  1236. # (*)	volatile register

  1237. # (-)	preserved by callee

  1238. # (#)	Nth argument, volatile

  1239. #

  1240. # In Unix terms top of stack is argument transfer area for arguments

  1241. # which could not be accommodated in registers. Or in other words 7th

  1242. # [integer] argument resides at 8(%rsp) upon function entry point.

  1243. # 128 bytes above %rsp constitute a "red zone" which is not touched

  1244. # by signal handlers and can be used as temporal storage without

  1245. # allocating a frame.

  1246. #

  1247. # In Win64 terms N*8 bytes on top of stack is argument transfer area,

  1248. # which belongs to/can be overwritten by callee. N is the number of

  1249. # arguments passed to callee, *but* not less than 4! This means that

  1250. # upon function entry point 5th argument resides at 40(%rsp), as well

  1251. # as that 32 bytes from 8(%rsp) can always be used as temporal

  1252. # storage [without allocating a frame]. One can actually argue that

  1253. # one can assume a "red zone" above stack pointer under Win64 as well.

  1254. # Point is that at apparently no occasion Windows kernel would alter

  1255. # the area above user stack pointer in true asynchronous manner...

  1256. #

  1257. # All the above means that if assembler programmer adheres to Unix

  1258. # register and stack layout, but disregards the "red zone" existence,

  1259. # it's possible to use following prologue and epilogue to "gear" from

  1260. # Unix to Win64 ABI in leaf functions with not more than 6 arguments.

  1261. #

  1262. # omnipotent_function:

  1263. # ifdef WIN64

  1264. #	movq	%rdi,8(%rsp)

  1265. #	movq	%rsi,16(%rsp)

  1266. #	movq	%rcx,%rdi	; if 1st argument is actually present

  1267. #	movq	%rdx,%rsi	; if 2nd argument is actually ...

  1268. #	movq	%r8,%rdx	; if 3rd argument is ...

  1269. #	movq	%r9,%rcx	; if 4th argument ...

  1270. #	movq	40(%rsp),%r8	; if 5th ...

  1271. #	movq	48(%rsp),%r9	; if 6th ...

  1272. # endif

  1273. #	...

  1274. # ifdef WIN64

  1275. #	movq	8(%rsp),%rdi

  1276. #	movq	16(%rsp),%rsi

  1277. # endif

  1278. #	ret

  1279. #

  1280. #################################################

  1281. # Win64 SEH, Structured Exception Handling.

  1282. #

  1283. # Unlike on Unix systems(*) lack of Win64 stack unwinding information

  1284. # has undesired side-effect at run-time: if an exception is raised in

  1285. # assembler subroutine such as those in question (basically we're

  1286. # referring to segmentation violations caused by malformed input

  1287. # parameters), the application is briskly terminated without invoking

  1288. # any exception handlers, most notably without generating memory dump

  1289. # or any user notification whatsoever. This poses a problem. It's

  1290. # possible to address it by registering custom language-specific

  1291. # handler that would restore processor context to the state at

  1292. # subroutine entry point and return "exception is not handled, keep

  1293. # unwinding" code. Writing such handler can be a challenge... But it's

  1294. # doable, though requires certain coding convention. Consider following

  1295. # snippet:

  1296. #

  1297. # .type	function,@function

  1298. # function:

  1299. #	movq	%rsp,%rax	# copy rsp to volatile register

  1300. #	pushq	%r15		# save non-volatile registers

  1301. #	pushq	%rbx

  1302. #	pushq	%rbp

  1303. #	movq	%rsp,%r11

  1304. #	subq	%rdi,%r11	# prepare [variable] stack frame

  1305. #	andq	$-64,%r11

  1306. #	movq	%rax,0(%r11)	# check for exceptions

  1307. #	movq	%r11,%rsp	# allocate [variable] stack frame

  1308. #	movq	%rax,0(%rsp)	# save original rsp value

  1309. # magic_point:

  1310. #	...

  1311. #	movq	0(%rsp),%rcx	# pull original rsp value

  1312. #	movq	-24(%rcx),%rbp	# restore non-volatile registers

  1313. #	movq	-16(%rcx),%rbx

  1314. #	movq	-8(%rcx),%r15

  1315. #	movq	%rcx,%rsp	# restore original rsp

  1316. # magic_epilogue:

  1317. #	ret

  1318. # .size function,.-function

  1319. #

  1320. # The key is that up to magic_point copy of original rsp value remains

  1321. # in chosen volatile register and no non-volatile register, except for

  1322. # rsp, is modified. While past magic_point rsp remains constant till

  1323. # the very end of the function. In this case custom language-specific

  1324. # exception handler would look like this:

  1325. #

  1326. # EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame,

  1327. #		CONTEXT *context,DISPATCHER_CONTEXT *disp)

  1328. # {	ULONG64 *rsp = (ULONG64 *)context->Rax;

  1329. #	ULONG64  rip = context->Rip;

  1330. #

  1331. #	if (rip >= magic_point)

  1332. #	{   rsp = (ULONG64 *)context->Rsp;

  1333. #	    if (rip < magic_epilogue)

  1334. #	    {	rsp = (ULONG64 *)rsp[0];

  1335. #		context->Rbp = rsp[-3];

  1336. #		context->Rbx = rsp[-2];

  1337. #		context->R15 = rsp[-1];

  1338. #	    }

  1339. #	}

  1340. #	context->Rsp = (ULONG64)rsp;

  1341. #	context->Rdi = rsp[1];

  1342. #	context->Rsi = rsp[2];

  1343. #

  1344. #	memcpy (disp->ContextRecord,context,sizeof(CONTEXT));

  1345. #	RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase,

  1346. #		dips->ControlPc,disp->FunctionEntry,disp->ContextRecord,

  1347. #		&disp->HandlerData,&disp->EstablisherFrame,NULL);

  1348. #	return ExceptionContinueSearch;

  1349. # }

  1350. #

  1351. # It's appropriate to implement this handler in assembler, directly in

  1352. # function's module. In order to do that one has to know members'

  1353. # offsets in CONTEXT and DISPATCHER_CONTEXT structures and some constant

  1354. # values. Here they are:

  1355. #

  1356. #	CONTEXT.Rax				120

  1357. #	CONTEXT.Rcx				128

  1358. #	CONTEXT.Rdx				136

  1359. #	CONTEXT.Rbx				144

  1360. #	CONTEXT.Rsp				152

  1361. #	CONTEXT.Rbp				160

  1362. #	CONTEXT.Rsi				168

  1363. #	CONTEXT.Rdi				176

  1364. #	CONTEXT.R8				184

  1365. #	CONTEXT.R9				192

  1366. #	CONTEXT.R10				200

  1367. #	CONTEXT.R11				208

  1368. #	CONTEXT.R12				216

  1369. #	CONTEXT.R13				224

  1370. #	CONTEXT.R14				232

  1371. #	CONTEXT.R15				240

  1372. #	CONTEXT.Rip				248

  1373. #	CONTEXT.Xmm6				512

  1374. #	sizeof(CONTEXT)				1232

  1375. #	DISPATCHER_CONTEXT.ControlPc		0

  1376. #	DISPATCHER_CONTEXT.ImageBase		8

  1377. #	DISPATCHER_CONTEXT.FunctionEntry	16

  1378. #	DISPATCHER_CONTEXT.EstablisherFrame	24

  1379. #	DISPATCHER_CONTEXT.TargetIp		32

  1380. #	DISPATCHER_CONTEXT.ContextRecord	40

  1381. #	DISPATCHER_CONTEXT.LanguageHandler	48

  1382. #	DISPATCHER_CONTEXT.HandlerData		56

  1383. #	UNW_FLAG_NHANDLER			0

  1384. #	ExceptionContinueSearch			1

  1385. #

  1386. # In order to tie the handler to the function one has to compose

  1387. # couple of structures: one for .xdata segment and one for .pdata.

  1388. #

  1389. # UNWIND_INFO structure for .xdata segment would be

  1390. #

  1391. # function_unwind_info:

  1392. #	.byte	9,0,0,0

  1393. #	.rva	handler

  1394. #

  1395. # This structure designates exception handler for a function with

  1396. # zero-length prologue, no stack frame or frame register.

  1397. #

  1398. # To facilitate composing of .pdata structures, auto-generated "gear"

  1399. # prologue copies rsp value to rax and denotes next instruction with

  1400. # .LSEH_begin_{function_name} label. This essentially defines the SEH

  1401. # styling rule mentioned in the beginning. Position of this label is

  1402. # chosen in such manner that possible exceptions raised in the "gear"

  1403. # prologue would be accounted to caller and unwound from latter's frame.

  1404. # End of function is marked with respective .LSEH_end_{function_name}

  1405. # label. To summarize, .pdata segment would contain

  1406. #

  1407. #	.rva	.LSEH_begin_function

  1408. #	.rva	.LSEH_end_function

  1409. #	.rva	function_unwind_info

  1410. #

  1411. # Reference to function_unwind_info from .xdata segment is the anchor.

  1412. # In case you wonder why references are 32-bit .rvas and not 64-bit

  1413. # .quads. References put into these two segments are required to be

  1414. # *relative* to the base address of the current binary module, a.k.a.

  1415. # image base. No Win64 module, be it .exe or .dll, can be larger than

  1416. # 2GB and thus such relative references can be and are accommodated in

  1417. # 32 bits.

  1418. #

  1419. # Having reviewed the example function code, one can argue that "movq

  1420. # %rsp,%rax" above is redundant. It is not! Keep in mind that on Unix

  1421. # rax would contain an undefined value. If this "offends" you, use

  1422. # another register and refrain from modifying rax till magic_point is

  1423. # reached, i.e. as if it was a non-volatile register. If more registers

  1424. # are required prior [variable] frame setup is completed, note that

  1425. # nobody says that you can have only one "magic point." You can

  1426. # "liberate" non-volatile registers by denoting last stack off-load

  1427. # instruction and reflecting it in finer grade unwind logic in handler.

  1428. # After all, isn't it why it's called *language-specific* handler...

  1429. #

  1430. # SE handlers are also involved in unwinding stack when executable is

  1431. # profiled or debugged. Profiling implies additional limitations that

  1432. # are too subtle to discuss here. For now it's sufficient to say that

  1433. # in order to simplify handlers one should either a) offload original

  1434. # %rsp to stack (like discussed above); or b) if you have a register to

  1435. # spare for frame pointer, choose volatile one.

  1436. #

  1437. # (*)	Note that we're talking about run-time, not debug-time. Lack of

  1438. #	unwind information makes debugging hard on both Windows and

  1439. #	Unix. "Unlike" referes to the fact that on Unix signal handler

  1440. #	will always be invoked, core dumped and appropriate exit code

  1441. #	returned to parent (for user notification).