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[thirdparty/openssl.git] / crypto / perlasm / x86_64-xlate.pl
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1cfd258e
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1#!/usr/bin/env perl
2
80aa9cc9 3# Ascetic x86_64 AT&T to MASM/NASM assembler translator by <appro>.
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4#
5# Why AT&T to MASM and not vice versa? Several reasons. Because AT&T
6# format is way easier to parse. Because it's simpler to "gear" from
7# Unix ABI to Windows one [see cross-reference "card" at the end of
8# file]. Because Linux targets were available first...
9#
10# In addition the script also "distills" code suitable for GNU
11# assembler, so that it can be compiled with more rigid assemblers,
12# such as Solaris /usr/ccs/bin/as.
13#
14# This translator is not designed to convert *arbitrary* assembler
15# code from AT&T format to MASM one. It's designed to convert just
16# enough to provide for dual-ABI OpenSSL modules development...
17# There *are* limitations and you might have to modify your assembler
18# code or this script to achieve the desired result...
19#
20# Currently recognized limitations:
21#
22# - can't use multiple ops per line;
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23#
24# Dual-ABI styling rules.
25#
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26# 1. Adhere to Unix register and stack layout [see cross-reference
27# ABI "card" at the end for explanation].
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28# 2. Forget about "red zone," stick to more traditional blended
29# stack frame allocation. If volatile storage is actually required
30# that is. If not, just leave the stack as is.
31# 3. Functions tagged with ".type name,@function" get crafted with
4b450519 32# unified Win64 prologue and epilogue automatically. If you want
1cfd258e 33# to take care of ABI differences yourself, tag functions as
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34# ".type name,@abi-omnipotent" instead.
35# 4. To optimize the Win64 prologue you can specify number of input
36# arguments as ".type name,@function,N." Keep in mind that if N is
37# larger than 6, then you *have to* write "abi-omnipotent" code,
38# because >6 cases can't be addressed with unified prologue.
39# 5. Name local labels as .L*, do *not* use dynamic labels such as 1:
40# (sorry about latter).
41# 6. Don't use [or hand-code with .byte] "rep ret." "ret" mnemonic is
42# required to identify the spots, where to inject Win64 epilogue!
43# But on the pros, it's then prefixed with rep automatically:-)
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44# 7. Stick to explicit ip-relative addressing. If you have to use
45# GOTPCREL addressing, stick to mov symbol@GOTPCREL(%rip),%r??.
46# Both are recognized and translated to proper Win64 addressing
47# modes. To support legacy code a synthetic directive, .picmeup,
48# is implemented. It puts address of the *next* instruction into
49# target register, e.g.:
5d0d60e2 50#
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51# .picmeup %rax
52# lea .Label-.(%rax),%rax
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53#
54# 8. In order to provide for structured exception handling unified
55# Win64 prologue copies %rsp value to %rax. For further details
56# see SEH paragraph at the end.
85253772 57# 9. .init segment is allowed to contain calls to functions only.
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58# a. If function accepts more than 4 arguments *and* >4th argument
59# is declared as non 64-bit value, do clear its upper part.
80aa9cc9 60\f
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61my $flavour = shift;
62my $output = shift;
63if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
932cc129 64
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65open STDOUT,">$output" || die "can't open $output: $!"
66 if (defined($output));
1cfd258e 67
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68my $gas=1; $gas=0 if ($output =~ /\.asm$/);
69my $elf=1; $elf=0 if (!$gas);
70my $win64=0;
71my $prefix="";
93c4ba07 72my $decor=".L";
a23e3dbe 73
8ab9025e 74my $masmref=8 + 50727*2**-32; # 8.00.50727 shipped with VS2005
9b634c9b 75my $masm=0;
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76my $PTR=" PTR";
77
9b634c9b 78my $nasmref=2.03;
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79my $nasm=0;
80
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81if ($flavour eq "mingw64") { $gas=1; $elf=0; $win64=1;
82 $prefix=`echo __USER_LABEL_PREFIX__ | $ENV{CC} -E -P -`;
9ba96fbb 83 $prefix =~ s|\R$||; # Better chomp
f9a152bd 84 }
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85elsif ($flavour eq "macosx") { $gas=1; $elf=0; $prefix="_"; $decor="L\$"; }
86elsif ($flavour eq "masm") { $gas=0; $elf=0; $masm=$masmref; $win64=1; $decor="\$L\$"; }
87elsif ($flavour eq "nasm") { $gas=0; $elf=0; $nasm=$nasmref; $win64=1; $decor="\$L\$"; $PTR=""; }
85253772 88elsif (!$gas)
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89{ if ($ENV{ASM} =~ m/nasm/ && `nasm -v` =~ m/version ([0-9]+)\.([0-9]+)/i)
90 { $nasm = $1 + $2*0.01; $PTR=""; }
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91 elsif (`ml64 2>&1` =~ m/Version ([0-9]+)\.([0-9]+)(\.([0-9]+))?/)
92 { $masm = $1 + $2*2**-16 + $4*2**-32; }
9b634c9b 93 die "no assembler found on %PATH" if (!($nasm || $masm));
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94 $win64=1;
95 $elf=0;
93c4ba07 96 $decor="\$L\$";
a23e3dbe 97}
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98
99my $current_segment;
100my $current_function;
9b634c9b 101my %globals;
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102
103{ package opcode; # pick up opcodes
104 sub re {
105 my $self = shift; # single instance in enough...
106 local *line = shift;
107 undef $ret;
108
932cc129 109 if ($line =~ /^([a-z][a-z0-9]*)/i) {
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110 $self->{op} = $1;
111 $ret = $self;
112 $line = substr($line,@+[0]); $line =~ s/^\s+//;
113
114 undef $self->{sz};
272ba870 115 if ($self->{op} =~ /^(movz)x?([bw]).*/) { # movz is pain...
1cfd258e 116 $self->{op} = $1;
272ba870 117 $self->{sz} = $2;
9b634c9b 118 } elsif ($self->{op} =~ /call|jmp/) {
fead2539 119 $self->{sz} = "";
a9e790b9 120 } elsif ($self->{op} =~ /^p/ && $' !~ /^(ush|op|insrw)/) { # SSEn
fead2539 121 $self->{sz} = "";
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122 } elsif ($self->{op} =~ /^v/) { # VEX
123 $self->{sz} = "";
902b30df 124 } elsif ($self->{op} =~ /mov[dq]/ && $line =~ /%xmm/) {
c7b903e0 125 $self->{sz} = "";
a078befc 126 } elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) {
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127 $self->{op} = $1;
128 $self->{sz} = $2;
129 }
130 }
131 $ret;
132 }
133 sub size {
134 my $self = shift;
135 my $sz = shift;
136 $self->{sz} = $sz if (defined($sz) && !defined($self->{sz}));
137 $self->{sz};
138 }
139 sub out {
140 my $self = shift;
85253772 141 if ($gas) {
932cc129 142 if ($self->{op} eq "movz") { # movz is pain...
1cfd258e 143 sprintf "%s%s%s",$self->{op},$self->{sz},shift;
932cc129
AP
144 } elsif ($self->{op} =~ /^set/) {
145 "$self->{op}";
1cfd258e 146 } elsif ($self->{op} eq "ret") {
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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 && $current_segment eq ".init") {
154 ".p2align\t3\n\t.quad";
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155 } else {
156 "$self->{op}$self->{sz}";
157 }
158 } else {
a078befc 159 $self->{op} =~ s/^movz/movzx/;
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160 if ($self->{op} eq "ret") {
161 $self->{op} = "";
85253772 162 if ($win64 && $current_function->{abi} eq "svr4") {
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163 $self->{op} = "mov rdi,QWORD${PTR}[8+rsp]\t;WIN64 epilogue\n\t".
164 "mov rsi,QWORD${PTR}[16+rsp]\n\t";
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165 }
166 $self->{op} .= "DB\t0F3h,0C3h\t\t;repret";
85253772 167 } elsif ($self->{op} =~ /^(pop|push)f/) {
80aa9cc9 168 $self->{op} .= $self->{sz};
85253772 169 } elsif ($self->{op} eq "call" && $current_segment eq ".CRT\$XCU") {
d6522548 170 $self->{op} = "\tDQ";
85253772 171 }
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172 $self->{op};
173 }
174 }
85253772
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175 sub mnemonic {
176 my $self=shift;
177 my $op=shift;
178 $self->{op}=$op if (defined($op));
179 $self->{op};
180 }
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181}
182{ package const; # pick up constants, which start with $
183 sub re {
184 my $self = shift; # single instance in enough...
185 local *line = shift;
186 undef $ret;
187
188 if ($line =~ /^\$([^,]+)/) {
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;
5d0d60e2 197
6e42e3ff 198 $self->{value} =~ s/\b(0b[0-1]+)/oct($1)/eig;
85253772 199 if ($gas) {
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200 # Solaris /usr/ccs/bin/as can't handle multiplications
201 # in $self->{value}
fd7dc201
AP
202 my $value = $self->{value};
203 $value =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi;
204 if ($value =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg) {
205 $self->{value} = $value;
206 }
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AP
207 sprintf "\$%s",$self->{value};
208 } else {
e8169520 209 $self->{value} =~ s/0x([0-9a-f]+)/0$1h/ig if ($masm);
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210 sprintf "%s",$self->{value};
211 }
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212 }
213}
214{ package ea; # pick up effective addresses: expr(%reg,%reg,scale)
215 sub re {
216 my $self = shift; # single instance in enough...
217 local *line = shift;
218 undef $ret;
219
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AP
220 # optional * ---vvv--- appears in indirect jmp/call
221 if ($line =~ /^(\*?)([^\(,]*)\(([%\w,]+)\)/) {
222 $self->{asterisk} = $1;
223 $self->{label} = $2;
224 ($self->{base},$self->{index},$self->{scale})=split(/,/,$3);
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225 $self->{scale} = 1 if (!defined($self->{scale}));
226 $ret = $self;
227 $line = substr($line,@+[0]); $line =~ s/^\s+//;
228
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AP
229 if ($win64 && $self->{label} =~ s/\@GOTPCREL//) {
230 die if (opcode->mnemonic() ne "mov");
231 opcode->mnemonic("lea");
232 }
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233 $self->{base} =~ s/^%//;
234 $self->{index} =~ s/^%// if (defined($self->{index}));
235 }
236 $ret;
237 }
238 sub size {}
239 sub out {
240 my $self = shift;
241 my $sz = shift;
242
85253772 243 $self->{label} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;
93c4ba07 244 $self->{label} =~ s/\.L/$decor/g;
85253772 245
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AP
246 # Silently convert all EAs to 64-bit. This is required for
247 # elder GNU assembler and results in more compact code,
248 # *but* most importantly AES module depends on this feature!
249 $self->{index} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/;
250 $self->{base} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/;
251
6fa4c7c4
AP
252 # Solaris /usr/ccs/bin/as can't handle multiplications
253 # in $self->{label}, new gas requires sign extension...
254 use integer;
255 $self->{label} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi;
667053a2
AP
256 $self->{label} =~ s/\b([0-9]+\s*[\*\/\%]\s*[0-9]+)\b/eval($1)/eg;
257 $self->{label} =~ s/\b([0-9]+)\b/$1<<32>>32/eg;
6fa4c7c4 258
22de0e65
AP
259 if (!$self->{label} && $self->{index} && $self->{scale}==1 &&
260 $self->{base} =~ /(rbp|r13)/) {
261 $self->{base} = $self->{index}; $self->{index} = $1;
262 }
263
85253772 264 if ($gas) {
93c4ba07 265 $self->{label} =~ s/^___imp_/__imp__/ if ($flavour eq "mingw64");
4b450519 266
1cfd258e 267 if (defined($self->{index})) {
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AP
268 sprintf "%s%s(%s,%%%s,%d)",$self->{asterisk},
269 $self->{label},
270 $self->{base}?"%$self->{base}":"",
1cfd258e 271 $self->{index},$self->{scale};
5d0d60e2 272 } else {
9b634c9b 273 sprintf "%s%s(%%%s)", $self->{asterisk},$self->{label},$self->{base};
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274 }
275 } else {
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276 %szmap = ( b=>"BYTE$PTR", w=>"WORD$PTR",
277 l=>"DWORD$PTR", d=>"DWORD$PTR",
278 q=>"QWORD$PTR", o=>"OWORD$PTR",
279 x=>"XMMWORD$PTR", y=>"YMMWORD$PTR", z=>"ZMMWORD$PTR" );
1cfd258e 280
70cf3095 281 $self->{label} =~ s/\./\$/g;
f9a152bd 282 $self->{label} =~ s/(?<![\w\$\.])0x([0-9a-f]+)/0$1h/ig;
70cf3095 283 $self->{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/);
1b0fe79f
AP
284
285 ($self->{asterisk}) && ($sz="q") ||
286 (opcode->mnemonic() =~ /^v?mov([qd])$/) && ($sz=$1) ||
287 (opcode->mnemonic() =~ /^v?pinsr([qdwb])$/) && ($sz=$1) ||
288 (opcode->mnemonic() =~ /^vpbroadcast([qdwb])$/) && ($sz=$1) ||
d405aa2f 289 (opcode->mnemonic() =~ /^v(?!perm)[a-z]+[fi]128$/) && ($sz="x");
70cf3095 290
1cfd258e 291 if (defined($self->{index})) {
b5c6aab5 292 sprintf "%s[%s%s*%d%s]",$szmap{$sz},
a23e3dbe 293 $self->{label}?"$self->{label}+":"",
1cfd258e 294 $self->{index},$self->{scale},
b5c6aab5 295 $self->{base}?"+$self->{base}":"";
932cc129 296 } elsif ($self->{base} eq "rip") {
a23e3dbe 297 sprintf "%s[%s]",$szmap{$sz},$self->{label};
5d0d60e2 298 } else {
a23e3dbe
AP
299 sprintf "%s[%s%s]",$szmap{$sz},
300 $self->{label}?"$self->{label}+":"",
301 $self->{base};
1cfd258e
AP
302 }
303 }
304 }
305}
306{ package register; # pick up registers, which start with %.
307 sub re {
0d4fb843 308 my $class = shift; # multiple instances...
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AP
309 my $self = {};
310 local *line = shift;
311 undef $ret;
312
9b634c9b
AP
313 # optional * ---vvv--- appears in indirect jmp/call
314 if ($line =~ /^(\*?)%(\w+)/) {
1cfd258e 315 bless $self,$class;
9b634c9b
AP
316 $self->{asterisk} = $1;
317 $self->{value} = $2;
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AP
318 $ret = $self;
319 $line = substr($line,@+[0]); $line =~ s/^\s+//;
320 }
321 $ret;
322 }
323 sub size {
324 my $self = shift;
325 undef $ret;
326
327 if ($self->{value} =~ /^r[\d]+b$/i) { $ret="b"; }
328 elsif ($self->{value} =~ /^r[\d]+w$/i) { $ret="w"; }
329 elsif ($self->{value} =~ /^r[\d]+d$/i) { $ret="l"; }
330 elsif ($self->{value} =~ /^r[\w]+$/i) { $ret="q"; }
331 elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; }
332 elsif ($self->{value} =~ /^[\w]{2}l$/i) { $ret="b"; }
333 elsif ($self->{value} =~ /^[\w]{2}$/i) { $ret="w"; }
334 elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; }
335
336 $ret;
337 }
338 sub out {
339 my $self = shift;
85253772 340 if ($gas) { sprintf "%s%%%s",$self->{asterisk},$self->{value}; }
9b634c9b 341 else { $self->{value}; }
1cfd258e
AP
342 }
343}
344{ package label; # pick up labels, which end with :
345 sub re {
346 my $self = shift; # single instance is enough...
347 local *line = shift;
348 undef $ret;
349
85253772 350 if ($line =~ /(^[\.\w]+)\:/) {
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AP
351 $self->{value} = $1;
352 $ret = $self;
353 $line = substr($line,@+[0]); $line =~ s/^\s+//;
354
93c4ba07 355 $self->{value} =~ s/^\.L/$decor/;
1cfd258e
AP
356 }
357 $ret;
358 }
359 sub out {
360 my $self = shift;
361
85253772
AP
362 if ($gas) {
363 my $func = ($globals{$self->{value}} or $self->{value}) . ":";
364 if ($win64 &&
365 $current_function->{name} eq $self->{value} &&
366 $current_function->{abi} eq "svr4") {
367 $func .= "\n";
368 $func .= " movq %rdi,8(%rsp)\n";
369 $func .= " movq %rsi,16(%rsp)\n";
370 $func .= " movq %rsp,%rax\n";
93c4ba07 371 $func .= "${decor}SEH_begin_$current_function->{name}:\n";
85253772
AP
372 my $narg = $current_function->{narg};
373 $narg=6 if (!defined($narg));
374 $func .= " movq %rcx,%rdi\n" if ($narg>0);
375 $func .= " movq %rdx,%rsi\n" if ($narg>1);
376 $func .= " movq %r8,%rdx\n" if ($narg>2);
377 $func .= " movq %r9,%rcx\n" if ($narg>3);
378 $func .= " movq 40(%rsp),%r8\n" if ($narg>4);
379 $func .= " movq 48(%rsp),%r9\n" if ($narg>5);
380 }
381 $func;
382 } elsif ($self->{value} ne "$current_function->{name}") {
9b634c9b 383 $self->{value} .= ":" if ($masm && $ret!~m/^\$/);
85253772
AP
384 $self->{value} . ":";
385 } elsif ($win64 && $current_function->{abi} eq "svr4") {
9b634c9b
AP
386 my $func = "$current_function->{name}" .
387 ($nasm ? ":" : "\tPROC $current_function->{scope}") .
388 "\n";
389 $func .= " mov QWORD${PTR}[8+rsp],rdi\t;WIN64 prologue\n";
390 $func .= " mov QWORD${PTR}[16+rsp],rsi\n";
80aa9cc9 391 $func .= " mov rax,rsp\n";
93c4ba07 392 $func .= "${decor}SEH_begin_$current_function->{name}:";
80aa9cc9
AP
393 $func .= ":" if ($masm);
394 $func .= "\n";
1cfd258e
AP
395 my $narg = $current_function->{narg};
396 $narg=6 if (!defined($narg));
397 $func .= " mov rdi,rcx\n" if ($narg>0);
398 $func .= " mov rsi,rdx\n" if ($narg>1);
399 $func .= " mov rdx,r8\n" if ($narg>2);
400 $func .= " mov rcx,r9\n" if ($narg>3);
a23e3dbe
AP
401 $func .= " mov r8,QWORD${PTR}[40+rsp]\n" if ($narg>4);
402 $func .= " mov r9,QWORD${PTR}[48+rsp]\n" if ($narg>5);
1cfd258e
AP
403 $func .= "\n";
404 } else {
9b634c9b
AP
405 "$current_function->{name}".
406 ($nasm ? ":" : "\tPROC $current_function->{scope}");
1cfd258e
AP
407 }
408 }
409}
410{ package expr; # pick up expressioins
411 sub re {
412 my $self = shift; # single instance is enough...
413 local *line = shift;
414 undef $ret;
415
416 if ($line =~ /(^[^,]+)/) {
417 $self->{value} = $1;
418 $ret = $self;
419 $line = substr($line,@+[0]); $line =~ s/^\s+//;
420
85253772
AP
421 $self->{value} =~ s/\@PLT// if (!$elf);
422 $self->{value} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;
93c4ba07 423 $self->{value} =~ s/\.L/$decor/g;
1cfd258e
AP
424 }
425 $ret;
426 }
427 sub out {
428 my $self = shift;
667053a2 429 if ($nasm && opcode->mnemonic()=~m/^j(?![re]cxz)/) {
9b634c9b
AP
430 "NEAR ".$self->{value};
431 } else {
432 $self->{value};
433 }
1cfd258e
AP
434 }
435}
436{ package directive; # pick up directives, which start with .
437 sub re {
438 my $self = shift; # single instance is enough...
439 local *line = shift;
440 undef $ret;
441 my $dir;
5d0d60e2
AP
442 my %opcode = # lea 2f-1f(%rip),%dst; 1: nop; 2:
443 ( "%rax"=>0x01058d48, "%rcx"=>0x010d8d48,
444 "%rdx"=>0x01158d48, "%rbx"=>0x011d8d48,
445 "%rsp"=>0x01258d48, "%rbp"=>0x012d8d48,
446 "%rsi"=>0x01358d48, "%rdi"=>0x013d8d48,
447 "%r8" =>0x01058d4c, "%r9" =>0x010d8d4c,
448 "%r10"=>0x01158d4c, "%r11"=>0x011d8d4c,
449 "%r12"=>0x01258d4c, "%r13"=>0x012d8d4c,
450 "%r14"=>0x01358d4c, "%r15"=>0x013d8d4c );
1cfd258e
AP
451
452 if ($line =~ /^\s*(\.\w+)/) {
85253772
AP
453 $dir = $1;
454 $ret = $self;
455 undef $self->{value};
456 $line = substr($line,@+[0]); $line =~ s/^\s+//;
457
458 SWITCH: for ($dir) {
459 /\.picmeup/ && do { if ($line =~ /(%r[\w]+)/i) {
460 $dir="\t.long";
461 $line=sprintf "0x%x,0x90000000",$opcode{$1};
462 }
463 last;
464 };
465 /\.global|\.globl|\.extern/
466 && do { $globals{$line} = $prefix . $line;
467 $line = $globals{$line} if ($prefix);
468 last;
469 };
470 /\.type/ && do { ($sym,$type,$narg) = split(',',$line);
471 if ($type eq "\@function") {
472 undef $current_function;
473 $current_function->{name} = $sym;
474 $current_function->{abi} = "svr4";
475 $current_function->{narg} = $narg;
476 $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE";
477 } elsif ($type eq "\@abi-omnipotent") {
478 undef $current_function;
479 $current_function->{name} = $sym;
480 $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE";
481 }
482 $line =~ s/\@abi\-omnipotent/\@function/;
483 $line =~ s/\@function.*/\@function/;
484 last;
485 };
486 /\.asciz/ && do { if ($line =~ /^"(.*)"$/) {
487 $dir = ".byte";
488 $line = join(",",unpack("C*",$1),0);
489 }
490 last;
491 };
93c4ba07
AP
492 /\.rva|\.long|\.quad/
493 && do { $line =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;
494 $line =~ s/\.L/$decor/g;
495 last;
496 };
85253772
AP
497 }
498
499 if ($gas) {
500 $self->{value} = $dir . "\t" . $line;
501
502 if ($dir =~ /\.extern/) {
932cc129 503 $self->{value} = ""; # swallow extern
85253772
AP
504 } elsif (!$elf && $dir =~ /\.type/) {
505 $self->{value} = "";
506 $self->{value} = ".def\t" . ($globals{$1} or $1) . ";\t" .
507 (defined($globals{$1})?".scl 2;":".scl 3;") .
508 "\t.type 32;\t.endef"
509 if ($win64 && $line =~ /([^,]+),\@function/);
510 } elsif (!$elf && $dir =~ /\.size/) {
511 $self->{value} = "";
512 if (defined($current_function)) {
93c4ba07 513 $self->{value} .= "${decor}SEH_end_$current_function->{name}:"
85253772
AP
514 if ($win64 && $current_function->{abi} eq "svr4");
515 undef $current_function;
516 }
517 } elsif (!$elf && $dir =~ /\.align/) {
518 $self->{value} = ".p2align\t" . (log($line)/log(2));
519 } elsif ($dir eq ".section") {
520 $current_segment=$line;
521 if (!$elf && $current_segment eq ".init") {
522 if ($flavour eq "macosx") { $self->{value} = ".mod_init_func"; }
523 elsif ($flavour eq "mingw64") { $self->{value} = ".section\t.ctors"; }
524 }
525 } elsif ($dir =~ /\.(text|data)/) {
526 $current_segment=".$1";
ddc20d4d
AP
527 } elsif ($dir =~ /\.hidden/) {
528 if ($flavour eq "macosx") { $self->{value} = ".private_extern\t$prefix$line"; }
529 elsif ($flavour eq "mingw64") { $self->{value} = ""; }
530 } elsif ($dir =~ /\.comm/) {
531 $self->{value} = "$dir\t$prefix$line";
ff6f9f96 532 $self->{value} =~ s|,([0-9]+),([0-9]+)$|",$1,".log($2)/log(2)|e if ($flavour eq "macosx");
5d0d60e2 533 }
1cfd258e
AP
534 $line = "";
535 return $self;
536 }
537
85253772 538 # non-gas case or nasm/masm
1cfd258e 539 SWITCH: for ($dir) {
9b634c9b 540 /\.text/ && do { my $v=undef;
a23e3dbe 541 if ($nasm) {
9b634c9b 542 $v="section .text code align=64\n";
a23e3dbe
AP
543 } else {
544 $v="$current_segment\tENDS\n" if ($current_segment);
9b634c9b 545 $current_segment = ".text\$";
a23e3dbe 546 $v.="$current_segment\tSEGMENT ";
1b0fe79f 547 $v.=$masm>=$masmref ? "ALIGN(256)" : "PAGE";
a23e3dbe
AP
548 $v.=" 'CODE'";
549 }
1cfd258e
AP
550 $self->{value} = $v;
551 last;
552 };
9b634c9b
AP
553 /\.data/ && do { my $v=undef;
554 if ($nasm) {
555 $v="section .data data align=8\n";
556 } else {
557 $v="$current_segment\tENDS\n" if ($current_segment);
558 $current_segment = "_DATA";
559 $v.="$current_segment\tSEGMENT";
560 }
561 $self->{value} = $v;
562 last;
563 };
564 /\.section/ && do { my $v=undef;
85253772
AP
565 $line =~ s/([^,]*).*/$1/;
566 $line = ".CRT\$XCU" if ($line eq ".init");
9b634c9b
AP
567 if ($nasm) {
568 $v="section $line";
569 if ($line=~/\.([px])data/) {
570 $v.=" rdata align=";
571 $v.=$1 eq "p"? 4 : 8;
d6522548
AP
572 } elsif ($line=~/\.CRT\$/i) {
573 $v.=" rdata align=8";
9b634c9b
AP
574 }
575 } else {
576 $v="$current_segment\tENDS\n" if ($current_segment);
577 $v.="$line\tSEGMENT";
578 if ($line=~/\.([px])data/) {
579 $v.=" READONLY";
580 $v.=" ALIGN(".($1 eq "p" ? 4 : 8).")" if ($masm>=$masmref);
d6522548 581 } elsif ($line=~/\.CRT\$/i) {
e6903980
AP
582 $v.=" READONLY ";
583 $v.=$masm>=$masmref ? "ALIGN(8)" : "DWORD";
9b634c9b
AP
584 }
585 }
586 $current_segment = $line;
587 $self->{value} = $v;
588 last;
589 };
a23e3dbe 590 /\.extern/ && do { $self->{value} = "EXTERN\t".$line;
9b634c9b
AP
591 $self->{value} .= ":NEAR" if ($masm);
592 last;
593 };
80aa9cc9
AP
594 /\.globl|.global/
595 && do { $self->{value} = $masm?"PUBLIC":"global";
596 $self->{value} .= "\t".$line;
1cfd258e
AP
597 last;
598 };
5d0d60e2 599 /\.size/ && do { if (defined($current_function)) {
8fe8bae1
AP
600 undef $self->{value};
601 if ($current_function->{abi} eq "svr4") {
93c4ba07 602 $self->{value}="${decor}SEH_end_$current_function->{name}:";
8fe8bae1
AP
603 $self->{value}.=":\n" if($masm);
604 }
4010b341 605 $self->{value}.="$current_function->{name}\tENDP" if($masm && $current_function->{name});
1cfd258e
AP
606 undef $current_function;
607 }
608 last;
609 };
d405aa2f
AP
610 /\.align/ && do { my $max = ($masm && $masm>=$masmref) ? 256 : 4096;
611 $self->{value} = "ALIGN\t".($line>$max?$max:$line);
612 last;
613 };
85253772 614 /\.(value|long|rva|quad)/
80aa9cc9 615 && do { my $sz = substr($1,0,1);
fead2539 616 my @arr = split(/,\s*/,$line);
1cfd258e 617 my $last = pop(@arr);
a23e3dbe 618 my $conv = sub { my $var=shift;
065c5d63 619 $var=~s/^(0b[0-1]+)/oct($1)/eig;
fead2539 620 $var=~s/^0x([0-9a-f]+)/0$1h/ig if ($masm);
85253772 621 if ($sz eq "D" && ($current_segment=~/.[px]data/ || $dir eq ".rva"))
80aa9cc9 622 { $var=~s/([_a-z\$\@][_a-z0-9\$\@]*)/$nasm?"$1 wrt ..imagebase":"imagerel $1"/egi; }
9b634c9b 623 $var;
a23e3dbe 624 };
1cfd258e 625
85253772 626 $sz =~ tr/bvlrq/BWDDQ/;
1cfd258e 627 $self->{value} = "\tD$sz\t";
a23e3dbe
AP
628 for (@arr) { $self->{value} .= &$conv($_).","; }
629 $self->{value} .= &$conv($last);
1cfd258e
AP
630 last;
631 };
fead2539 632 /\.byte/ && do { my @str=split(/,\s*/,$line);
e8169520 633 map(s/(0b[0-1]+)/oct($1)/eig,@str);
bf785c98 634 map(s/0x([0-9a-f]+)/0$1h/ig,@str) if ($masm);
85253772 635 while ($#str>15) {
55eab3b7 636 $self->{value}.="DB\t"
85253772
AP
637 .join(",",@str[0..15])."\n";
638 foreach (0..15) { shift @str; }
d68ff710 639 }
85253772
AP
640 $self->{value}.="DB\t"
641 .join(",",@str) if (@str);
d68ff710
AP
642 last;
643 };
ddc20d4d
AP
644 /\.comm/ && do { my @str=split(/,\s*/,$line);
645 my $v=undef;
646 if ($nasm) {
301799b8 647 $v.="common $prefix@str[0] @str[1]";
ddc20d4d
AP
648 } else {
649 $v="$current_segment\tENDS\n" if ($current_segment);
94c64f9a 650 $current_segment = "_DATA";
ddc20d4d
AP
651 $v.="$current_segment\tSEGMENT\n";
652 $v.="COMM @str[0]:DWORD:".@str[1]/4;
653 }
654 $self->{value} = $v;
655 last;
656 };
1cfd258e
AP
657 }
658 $line = "";
659 }
660
661 $ret;
662 }
663 sub out {
664 my $self = shift;
665 $self->{value};
666 }
667}
668
fead2539
AP
669sub rex {
670 local *opcode=shift;
ddc20d4d
AP
671 my ($dst,$src,$rex)=@_;
672
673 $rex|=0x04 if($dst>=8);
674 $rex|=0x01 if($src>=8);
675 push @opcode,($rex|0x40) if ($rex);
fead2539
AP
676}
677
a9e790b9 678# older gas and ml64 don't handle SSE>2 instructions
fead2539
AP
679my %regrm = ( "%eax"=>0, "%ecx"=>1, "%edx"=>2, "%ebx"=>3,
680 "%esp"=>4, "%ebp"=>5, "%esi"=>6, "%edi"=>7 );
681
c7b903e0
AP
682my $movq = sub { # elderly gas can't handle inter-register movq
683 my $arg = shift;
684 my @opcode=(0x66);
a87ff751 685 if ($arg =~ /%xmm([0-9]+),\s*%r(\w+)/) {
c7b903e0
AP
686 my ($src,$dst)=($1,$2);
687 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; }
688 rex(\@opcode,$src,$dst,0x8);
689 push @opcode,0x0f,0x7e;
690 push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M
691 @opcode;
a87ff751 692 } elsif ($arg =~ /%r(\w+),\s*%xmm([0-9]+)/) {
c7b903e0
AP
693 my ($src,$dst)=($2,$1);
694 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; }
695 rex(\@opcode,$src,$dst,0x8);
696 push @opcode,0x0f,0x6e;
697 push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M
698 @opcode;
699 } else {
700 ();
701 }
702};
703
fead2539 704my $pextrd = sub {
a87ff751 705 if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*(%\w+)/) {
fead2539
AP
706 my @opcode=(0x66);
707 $imm=$1;
708 $src=$2;
a9e790b9 709 $dst=$3;
fead2539
AP
710 if ($dst =~ /%r([0-9]+)d/) { $dst = $1; }
711 elsif ($dst =~ /%e/) { $dst = $regrm{$dst}; }
712 rex(\@opcode,$src,$dst);
713 push @opcode,0x0f,0x3a,0x16;
714 push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M
715 push @opcode,$imm;
a9e790b9 716 @opcode;
fead2539 717 } else {
a9e790b9 718 ();
fead2539 719 }
a9e790b9 720};
fead2539
AP
721
722my $pinsrd = sub {
a87ff751 723 if (shift =~ /\$([0-9]+),\s*(%\w+),\s*%xmm([0-9]+)/) {
fead2539
AP
724 my @opcode=(0x66);
725 $imm=$1;
a9e790b9
AP
726 $src=$2;
727 $dst=$3;
b5c6aab5 728 if ($src =~ /%r([0-9]+)/) { $src = $1; }
fead2539
AP
729 elsif ($src =~ /%e/) { $src = $regrm{$src}; }
730 rex(\@opcode,$dst,$src);
731 push @opcode,0x0f,0x3a,0x22;
732 push @opcode,0xc0|(($dst&7)<<3)|($src&7); # ModR/M
733 push @opcode,$imm;
a9e790b9 734 @opcode;
fead2539 735 } else {
a9e790b9 736 ();
fead2539 737 }
a9e790b9 738};
fead2539
AP
739
740my $pshufb = sub {
a87ff751 741 if (shift =~ /%xmm([0-9]+),\s*%xmm([0-9]+)/) {
fead2539 742 my @opcode=(0x66);
a9e790b9 743 rex(\@opcode,$2,$1);
fead2539 744 push @opcode,0x0f,0x38,0x00;
a9e790b9
AP
745 push @opcode,0xc0|($1&7)|(($2&7)<<3); # ModR/M
746 @opcode;
fead2539 747 } else {
a9e790b9 748 ();
fead2539 749 }
a9e790b9 750};
fead2539 751
b5c6aab5 752my $palignr = sub {
a87ff751 753 if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {
b5c6aab5
AP
754 my @opcode=(0x66);
755 rex(\@opcode,$3,$2);
756 push @opcode,0x0f,0x3a,0x0f;
757 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M
758 push @opcode,$1;
759 @opcode;
760 } else {
761 ();
762 }
763};
764
765my $pclmulqdq = sub {
766 if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {
767 my @opcode=(0x66);
768 rex(\@opcode,$3,$2);
769 push @opcode,0x0f,0x3a,0x44;
770 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M
771 my $c=$1;
772 push @opcode,$c=~/^0/?oct($c):$c;
773 @opcode;
774 } else {
775 ();
776 }
777};
778
301799b8
AP
779my $rdrand = sub {
780 if (shift =~ /%[er](\w+)/) {
781 my @opcode=();
782 my $dst=$1;
783 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; }
784 rex(\@opcode,0,$1,8);
785 push @opcode,0x0f,0xc7,0xf0|($dst&7);
786 @opcode;
787 } else {
788 ();
789 }
790};
791
f4d45640
AP
792my $rdseed = sub {
793 if (shift =~ /%[er](\w+)/) {
794 my @opcode=();
795 my $dst=$1;
796 if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; }
797 rex(\@opcode,0,$1,8);
798 push @opcode,0x0f,0xc7,0xf8|($dst&7);
799 @opcode;
800 } else {
801 ();
802 }
803};
804
f6ff1aa8
AP
805sub rxb {
806 local *opcode=shift;
807 my ($dst,$src1,$src2,$rxb)=@_;
808
809 $rxb|=0x7<<5;
810 $rxb&=~(0x04<<5) if($dst>=8);
811 $rxb&=~(0x01<<5) if($src1>=8);
812 $rxb&=~(0x02<<5) if($src2>=8);
813 push @opcode,$rxb;
814}
815
816my $vprotd = sub {
817 if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {
818 my @opcode=(0x8f);
819 rxb(\@opcode,$3,$2,-1,0x08);
820 push @opcode,0x78,0xc2;
821 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M
822 my $c=$1;
823 push @opcode,$c=~/^0/?oct($c):$c;
824 @opcode;
825 } else {
826 ();
827 }
828};
829
830my $vprotq = sub {
831 if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {
832 my @opcode=(0x8f);
833 rxb(\@opcode,$3,$2,-1,0x08);
834 push @opcode,0x78,0xc3;
835 push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M
836 my $c=$1;
837 push @opcode,$c=~/^0/?oct($c):$c;
838 @opcode;
839 } else {
840 ();
841 }
842};
843
9b634c9b
AP
844if ($nasm) {
845 print <<___;
846default rel
a9e790b9 847%define XMMWORD
1b0fe79f
AP
848%define YMMWORD
849%define ZMMWORD
9b634c9b
AP
850___
851} elsif ($masm) {
852 print <<___;
853OPTION DOTNAME
854___
855}
ce3d25d3 856while(defined($line=<>)) {
1cfd258e 857
9ba96fbb 858 $line =~ s|\R$||; # Better chomp
1cfd258e 859
4b450519
AP
860 $line =~ s|[#!].*$||; # get rid of asm-style comments...
861 $line =~ s|/\*.*\*/||; # ... and C-style comments...
862 $line =~ s|^\s+||; # ... and skip white spaces in beginning
41965a84 863 $line =~ s|\s+$||; # ... and at the end
1cfd258e
AP
864
865 undef $label;
866 undef $opcode;
4db48824 867 undef @args;
1cfd258e
AP
868
869 if ($label=label->re(\$line)) { print $label->out(); }
870
871 if (directive->re(\$line)) {
872 printf "%s",directive->out();
a9e790b9
AP
873 } elsif ($opcode=opcode->re(\$line)) {
874 my $asm = eval("\$".$opcode->mnemonic());
875 undef @bytes;
876
877 if ((ref($asm) eq 'CODE') && scalar(@bytes=&$asm($line))) {
878 print $gas?".byte\t":"DB\t",join(',',@bytes),"\n";
879 next;
880 }
881
882 ARGUMENT: while (1) {
4db48824 883 my $arg;
1cfd258e 884
4db48824
AP
885 if ($arg=register->re(\$line)) { opcode->size($arg->size()); }
886 elsif ($arg=const->re(\$line)) { }
887 elsif ($arg=ea->re(\$line)) { }
888 elsif ($arg=expr->re(\$line)) { }
889 else { last ARGUMENT; }
1cfd258e 890
4db48824 891 push @args,$arg;
1cfd258e 892
4db48824 893 last ARGUMENT if ($line !~ /^,/);
1cfd258e 894
4db48824 895 $line =~ s/^,\s*//;
1cfd258e
AP
896 } # ARGUMENT:
897
4db48824
AP
898 if ($#args>=0) {
899 my $insn;
a9e790b9
AP
900 my $sz=opcode->size();
901
85253772 902 if ($gas) {
4db48824 903 $insn = $opcode->out($#args>=1?$args[$#args]->size():$sz);
fead2539 904 @args = map($_->out($sz),@args);
a9e790b9 905 printf "\t%s\t%s",$insn,join(",",@args);
5d0d60e2 906 } else {
4db48824 907 $insn = $opcode->out();
046ea308
AP
908 foreach (@args) {
909 my $arg = $_->out();
a9e790b9
AP
910 # $insn.=$sz compensates for movq, pinsrw, ...
911 if ($arg =~ /^xmm[0-9]+$/) { $insn.=$sz; $sz="x" if(!$sz); last; }
a9d14832 912 if ($arg =~ /^ymm[0-9]+$/) { $insn.=$sz; $sz="y" if(!$sz); last; }
1b0fe79f 913 if ($arg =~ /^zmm[0-9]+$/) { $insn.=$sz; $sz="z" if(!$sz); last; }
a9e790b9 914 if ($arg =~ /^mm[0-9]+$/) { $insn.=$sz; $sz="q" if(!$sz); last; }
046ea308 915 }
4db48824 916 @args = reverse(@args);
a23e3dbe 917 undef $sz if ($nasm && $opcode->mnemonic() eq "lea");
fead2539 918 printf "\t%s\t%s",$insn,join(",",map($_->out($sz),@args));
1cfd258e 919 }
1cfd258e
AP
920 } else {
921 printf "\t%s",$opcode->out();
922 }
923 }
924
925 print $line,"\n";
926}
927
85253772
AP
928print "\n$current_segment\tENDS\n" if ($current_segment && $masm);
929print "END\n" if ($masm);
1cfd258e
AP
930
931close STDOUT;
932
80aa9cc9 933\f#################################################
1cfd258e
AP
934# Cross-reference x86_64 ABI "card"
935#
936# Unix Win64
937# %rax * *
938# %rbx - -
939# %rcx #4 #1
940# %rdx #3 #2
941# %rsi #2 -
942# %rdi #1 -
943# %rbp - -
944# %rsp - -
945# %r8 #5 #3
946# %r9 #6 #4
947# %r10 * *
948# %r11 * *
949# %r12 - -
950# %r13 - -
951# %r14 - -
952# %r15 - -
953#
954# (*) volatile register
955# (-) preserved by callee
956# (#) Nth argument, volatile
957#
958# In Unix terms top of stack is argument transfer area for arguments
0d4fb843 959# which could not be accommodated in registers. Or in other words 7th
1cfd258e
AP
960# [integer] argument resides at 8(%rsp) upon function entry point.
961# 128 bytes above %rsp constitute a "red zone" which is not touched
962# by signal handlers and can be used as temporal storage without
963# allocating a frame.
964#
965# In Win64 terms N*8 bytes on top of stack is argument transfer area,
966# which belongs to/can be overwritten by callee. N is the number of
967# arguments passed to callee, *but* not less than 4! This means that
968# upon function entry point 5th argument resides at 40(%rsp), as well
969# as that 32 bytes from 8(%rsp) can always be used as temporal
d256b957
AP
970# storage [without allocating a frame]. One can actually argue that
971# one can assume a "red zone" above stack pointer under Win64 as well.
6a3a7f30
AP
972# Point is that at apparently no occasion Windows kernel would alter
973# the area above user stack pointer in true asynchronous manner...
1cfd258e
AP
974#
975# All the above means that if assembler programmer adheres to Unix
976# register and stack layout, but disregards the "red zone" existense,
977# it's possible to use following prologue and epilogue to "gear" from
978# Unix to Win64 ABI in leaf functions with not more than 6 arguments.
979#
980# omnipotent_function:
981# ifdef WIN64
982# movq %rdi,8(%rsp)
983# movq %rsi,16(%rsp)
984# movq %rcx,%rdi ; if 1st argument is actually present
985# movq %rdx,%rsi ; if 2nd argument is actually ...
986# movq %r8,%rdx ; if 3rd argument is ...
987# movq %r9,%rcx ; if 4th argument ...
988# movq 40(%rsp),%r8 ; if 5th ...
989# movq 48(%rsp),%r9 ; if 6th ...
990# endif
991# ...
992# ifdef WIN64
993# movq 8(%rsp),%rdi
994# movq 16(%rsp),%rsi
995# endif
996# ret
4f469342 997#
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998\f#################################################
999# Win64 SEH, Structured Exception Handling.
1000#
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1001# Unlike on Unix systems(*) lack of Win64 stack unwinding information
1002# has undesired side-effect at run-time: if an exception is raised in
1003# assembler subroutine such as those in question (basically we're
1004# referring to segmentation violations caused by malformed input
1005# parameters), the application is briskly terminated without invoking
1006# any exception handlers, most notably without generating memory dump
1007# or any user notification whatsoever. This poses a problem. It's
1008# possible to address it by registering custom language-specific
1009# handler that would restore processor context to the state at
1010# subroutine entry point and return "exception is not handled, keep
1011# unwinding" code. Writing such handler can be a challenge... But it's
1012# doable, though requires certain coding convention. Consider following
1013# snippet:
1014#
80aa9cc9 1015# .type function,@function
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1016# function:
1017# movq %rsp,%rax # copy rsp to volatile register
1018# pushq %r15 # save non-volatile registers
1019# pushq %rbx
1020# pushq %rbp
1021# movq %rsp,%r11
1022# subq %rdi,%r11 # prepare [variable] stack frame
1023# andq $-64,%r11
1024# movq %rax,0(%r11) # check for exceptions
1025# movq %r11,%rsp # allocate [variable] stack frame
1026# movq %rax,0(%rsp) # save original rsp value
1027# magic_point:
1028# ...
1029# movq 0(%rsp),%rcx # pull original rsp value
1030# movq -24(%rcx),%rbp # restore non-volatile registers
1031# movq -16(%rcx),%rbx
1032# movq -8(%rcx),%r15
1033# movq %rcx,%rsp # restore original rsp
1034# ret
80aa9cc9 1035# .size function,.-function
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1036#
1037# The key is that up to magic_point copy of original rsp value remains
1038# in chosen volatile register and no non-volatile register, except for
1039# rsp, is modified. While past magic_point rsp remains constant till
1040# the very end of the function. In this case custom language-specific
1041# exception handler would look like this:
1042#
1043# EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame,
1044# CONTEXT *context,DISPATCHER_CONTEXT *disp)
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1045# { ULONG64 *rsp = (ULONG64 *)context->Rax;
1046# if (context->Rip >= magic_point)
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1047# { rsp = ((ULONG64 **)context->Rsp)[0];
1048# context->Rbp = rsp[-3];
1049# context->Rbx = rsp[-2];
1050# context->R15 = rsp[-1];
1051# }
1052# context->Rsp = (ULONG64)rsp;
1053# context->Rdi = rsp[1];
1054# context->Rsi = rsp[2];
1055#
1056# memcpy (disp->ContextRecord,context,sizeof(CONTEXT));
1057# RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase,
1058# dips->ControlPc,disp->FunctionEntry,disp->ContextRecord,
1059# &disp->HandlerData,&disp->EstablisherFrame,NULL);
1060# return ExceptionContinueSearch;
1061# }
1062#
1063# It's appropriate to implement this handler in assembler, directly in
1064# function's module. In order to do that one has to know members'
1065# offsets in CONTEXT and DISPATCHER_CONTEXT structures and some constant
1066# values. Here they are:
1067#
1068# CONTEXT.Rax 120
1069# CONTEXT.Rcx 128
1070# CONTEXT.Rdx 136
1071# CONTEXT.Rbx 144
1072# CONTEXT.Rsp 152
1073# CONTEXT.Rbp 160
1074# CONTEXT.Rsi 168
1075# CONTEXT.Rdi 176
1076# CONTEXT.R8 184
1077# CONTEXT.R9 192
1078# CONTEXT.R10 200
1079# CONTEXT.R11 208
1080# CONTEXT.R12 216
1081# CONTEXT.R13 224
1082# CONTEXT.R14 232
1083# CONTEXT.R15 240
1084# CONTEXT.Rip 248
6dd9066e 1085# CONTEXT.Xmm6 512
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1086# sizeof(CONTEXT) 1232
1087# DISPATCHER_CONTEXT.ControlPc 0
1088# DISPATCHER_CONTEXT.ImageBase 8
1089# DISPATCHER_CONTEXT.FunctionEntry 16
1090# DISPATCHER_CONTEXT.EstablisherFrame 24
1091# DISPATCHER_CONTEXT.TargetIp 32
1092# DISPATCHER_CONTEXT.ContextRecord 40
1093# DISPATCHER_CONTEXT.LanguageHandler 48
1094# DISPATCHER_CONTEXT.HandlerData 56
1095# UNW_FLAG_NHANDLER 0
1096# ExceptionContinueSearch 1
1097#
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1098# In order to tie the handler to the function one has to compose
1099# couple of structures: one for .xdata segment and one for .pdata.
1100#
4f469342 1101# UNWIND_INFO structure for .xdata segment would be
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1102#
1103# function_unwind_info:
1104# .byte 9,0,0,0
85253772 1105# .rva handler
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1106#
1107# This structure designates exception handler for a function with
1108# zero-length prologue, no stack frame or frame register.
1109#
1110# To facilitate composing of .pdata structures, auto-generated "gear"
1111# prologue copies rsp value to rax and denotes next instruction with
85253772 1112# .LSEH_begin_{function_name} label. This essentially defines the SEH
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1113# styling rule mentioned in the beginning. Position of this label is
1114# chosen in such manner that possible exceptions raised in the "gear"
1115# prologue would be accounted to caller and unwound from latter's frame.
85253772 1116# End of function is marked with respective .LSEH_end_{function_name}
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1117# label. To summarize, .pdata segment would contain
1118#
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1119# .rva .LSEH_begin_function
1120# .rva .LSEH_end_function
1121# .rva function_unwind_info
80aa9cc9 1122#
478b50cf 1123# Reference to function_unwind_info from .xdata segment is the anchor.
85253772 1124# In case you wonder why references are 32-bit .rvas and not 64-bit
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1125# .quads. References put into these two segments are required to be
1126# *relative* to the base address of the current binary module, a.k.a.
1127# image base. No Win64 module, be it .exe or .dll, can be larger than
1128# 2GB and thus such relative references can be and are accommodated in
1129# 32 bits.
1130#
1131# Having reviewed the example function code, one can argue that "movq
1132# %rsp,%rax" above is redundant. It is not! Keep in mind that on Unix
1133# rax would contain an undefined value. If this "offends" you, use
1134# another register and refrain from modifying rax till magic_point is
1135# reached, i.e. as if it was a non-volatile register. If more registers
1136# are required prior [variable] frame setup is completed, note that
1137# nobody says that you can have only one "magic point." You can
1138# "liberate" non-volatile registers by denoting last stack off-load
1139# instruction and reflecting it in finer grade unwind logic in handler.
1140# After all, isn't it why it's called *language-specific* handler...
1141#
1142# Attentive reader can notice that exceptions would be mishandled in
1143# auto-generated "gear" epilogue. Well, exception effectively can't
1144# occur there, because if memory area used by it was subject to
1145# segmentation violation, then it would be raised upon call to the
1146# function (and as already mentioned be accounted to caller, which is
1147# not a problem). If you're still not comfortable, then define tail
1148# "magic point" just prior ret instruction and have handler treat it...
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1149#
1150# (*) Note that we're talking about run-time, not debug-time. Lack of
1151# unwind information makes debugging hard on both Windows and
1152# Unix. "Unlike" referes to the fact that on Unix signal handler
1153# will always be invoked, core dumped and appropriate exit code
1154# returned to parent (for user notification).