diff options
Diffstat (limited to 'crypto/perlasm/x86_64-xlate.pl')
| -rwxr-xr-x | crypto/perlasm/x86_64-xlate.pl | 906 |
1 files changed, 906 insertions, 0 deletions
diff --git a/crypto/perlasm/x86_64-xlate.pl b/crypto/perlasm/x86_64-xlate.pl new file mode 100755 index 0000000000..e4fc17bdbd --- /dev/null +++ b/crypto/perlasm/x86_64-xlate.pl @@ -0,0 +1,906 @@ +#!/usr/bin/env perl + +# Ascetic x86_64 AT&T to MASM/NASM assembler translator by <appro>. +# +# Why AT&T to MASM and not vice versa? Several reasons. Because AT&T +# format is way easier to parse. Because it's simpler to "gear" from +# Unix ABI to Windows one [see cross-reference "card" at the end of +# file]. Because Linux targets were available first... +# +# In addition the script also "distills" code suitable for GNU +# assembler, so that it can be compiled with more rigid assemblers, +# such as Solaris /usr/ccs/bin/as. +# +# This translator is not designed to convert *arbitrary* assembler +# code from AT&T format to MASM one. It's designed to convert just +# enough to provide for dual-ABI OpenSSL modules development... +# There *are* limitations and you might have to modify your assembler +# code or this script to achieve the desired result... +# +# Currently recognized limitations: +# +# - can't use multiple ops per line; +# +# Dual-ABI styling rules. +# +# 1. Adhere to Unix register and stack layout [see cross-reference +# ABI "card" at the end for explanation]. +# 2. Forget about "red zone," stick to more traditional blended +# stack frame allocation. If volatile storage is actually required +# that is. If not, just leave the stack as is. +# 3. Functions tagged with ".type name,@function" get crafted with +# unified Win64 prologue and epilogue automatically. If you want +# to take care of ABI differences yourself, tag functions as +# ".type name,@abi-omnipotent" instead. +# 4. To optimize the Win64 prologue you can specify number of input +# arguments as ".type name,@function,N." Keep in mind that if N is +# larger than 6, then you *have to* write "abi-omnipotent" code, +# because >6 cases can't be addressed with unified prologue. +# 5. Name local labels as .L*, do *not* use dynamic labels such as 1: +# (sorry about latter). +# 6. Don't use [or hand-code with .byte] "rep ret." "ret" mnemonic is +# required to identify the spots, where to inject Win64 epilogue! +# But on the pros, it's then prefixed with rep automatically:-) +# 7. Stick to explicit ip-relative addressing. If you have to use +# GOTPCREL addressing, stick to mov symbol@GOTPCREL(%rip),%r??. +# Both are recognized and translated to proper Win64 addressing +# modes. To support legacy code a synthetic directive, .picmeup, +# is implemented. It puts address of the *next* instruction into +# target register, e.g.: +# +# .picmeup %rax +# lea .Label-.(%rax),%rax +# +# 8. In order to provide for structured exception handling unified +# Win64 prologue copies %rsp value to %rax. For further details +# see SEH paragraph at the end. +# 9. .init segment is allowed to contain calls to functions only. + +my $flavour = shift; +my $output = shift; +if ($flavour =~ /\./) { $output = $flavour; undef $flavour; } + +{ my ($stddev,$stdino,@junk)=stat(STDOUT); + my ($outdev,$outino,@junk)=stat($output); + + open STDOUT,">$output" || die "can't open $output: $!" + if ($stddev!=$outdev || $stdino!=$outino); +} + +my $gas=1; $gas=0 if ($output =~ /\.asm$/); +my $elf=1; $elf=0 if (!$gas); +my $win64=0; +my $prefix=""; +my $decor=".L"; + +my $masmref=8 + 50727*2**-32; # 8.00.50727 shipped with VS2005 +my $masm=0; +my $PTR=" PTR"; + +my $nasmref=2.03; +my $nasm=0; + +if ($flavour eq "mingw64") { $gas=1; $elf=0; $win64=1; $prefix="_"; } +elsif ($flavour eq "macosx") { $gas=1; $elf=0; $prefix="_"; $decor="L\$"; } +elsif ($flavour eq "masm") { $gas=0; $elf=0; $masm=$masmref; $win64=1; $decor="\$L\$"; } +elsif ($flavour eq "nasm") { $gas=0; $elf=0; $nasm=$nasmref; $win64=1; $decor="\$L\$"; $PTR=""; } +elsif (!$gas) +{ if ($ENV{ASM} =~ m/nasm/ && `nasm -v` =~ m/version ([0-9]+)\.([0-9]+)/i) + { $nasm = $1 + $2*0.01; $PTR=""; } + elsif (`ml64 2>&1` =~ m/Version ([0-9]+)\.([0-9]+)(\.([0-9]+))?/) + { $masm = $1 + $2*2**-16 + $4*2**-32; } + die "no assembler found on %PATH" if (!($nasm || $masm)); + $win64=1; + $elf=0; + $decor="\$L\$"; +} + +my $current_segment; +my $current_function; +my %globals; + +{ package opcode; # pick up opcodes + sub re { + my $self = shift; # single instance in enough... + local *line = shift; + undef $ret; + + if ($line =~ /^([a-z][a-z0-9]*)/i) { + $self->{op} = $1; + $ret = $self; + $line = substr($line,@+[0]); $line =~ s/^\s+//; + + undef $self->{sz}; + if ($self->{op} =~ /^(movz)b.*/) { # movz is pain... + $self->{op} = $1; + $self->{sz} = "b"; + } elsif ($self->{op} =~ /call|jmp/) { + $self->{sz} = "" + } elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) { + $self->{op} = $1; + $self->{sz} = $2; + } + } + $ret; + } + sub size { + my $self = shift; + my $sz = shift; + $self->{sz} = $sz if (defined($sz) && !defined($self->{sz})); + $self->{sz}; + } + sub out { + my $self = shift; + if ($gas) { + if ($self->{op} eq "movz") { # movz is pain... + sprintf "%s%s%s",$self->{op},$self->{sz},shift; + } elsif ($self->{op} =~ /^set/) { + "$self->{op}"; + } elsif ($self->{op} eq "ret") { + my $epilogue = ""; + if ($win64 && $current_function->{abi} eq "svr4") { + $epilogue = "movq 8(%rsp),%rdi\n\t" . + "movq 16(%rsp),%rsi\n\t"; + } + $epilogue . ".byte 0xf3,0xc3"; + } elsif ($self->{op} eq "call" && !$elf && $current_segment eq ".init") { + ".p2align\t3\n\t.quad"; + } else { + "$self->{op}$self->{sz}"; + } + } else { + $self->{op} =~ s/^movz/movzx/; + if ($self->{op} eq "ret") { + $self->{op} = ""; + if ($win64 && $current_function->{abi} eq "svr4") { + $self->{op} = "mov rdi,QWORD${PTR}[8+rsp]\t;WIN64 epilogue\n\t". + "mov rsi,QWORD${PTR}[16+rsp]\n\t"; + } + $self->{op} .= "DB\t0F3h,0C3h\t\t;repret"; + } elsif ($self->{op} =~ /^(pop|push)f/) { + $self->{op} .= $self->{sz}; + } elsif ($self->{op} eq "call" && $current_segment eq ".CRT\$XCU") { + $self->{op} = "ALIGN\t8\n\tDQ"; + } + $self->{op}; + } + } + sub mnemonic { + my $self=shift; + my $op=shift; + $self->{op}=$op if (defined($op)); + $self->{op}; + } +} +{ package const; # pick up constants, which start with $ + sub re { + my $self = shift; # single instance in enough... + local *line = shift; + undef $ret; + + if ($line =~ /^\$([^,]+)/) { + $self->{value} = $1; + $ret = $self; + $line = substr($line,@+[0]); $line =~ s/^\s+//; + } + $ret; + } + sub out { + my $self = shift; + + if ($gas) { + # Solaris /usr/ccs/bin/as can't handle multiplications + # in $self->{value} + $self->{value} =~ s/(?<![0-9a-f])(0[x0-9a-f]+)/oct($1)/egi; + $self->{value} =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg; + sprintf "\$%s",$self->{value}; + } else { + $self->{value} =~ s/(0b[0-1]+)/oct($1)/eig; + $self->{value} =~ s/0x([0-9a-f]+)/0$1h/ig if ($masm); + sprintf "%s",$self->{value}; + } + } +} +{ package ea; # pick up effective addresses: expr(%reg,%reg,scale) + sub re { + my $self = shift; # single instance in enough... + local *line = shift; + undef $ret; + + # optional * ---vvv--- appears in indirect jmp/call + if ($line =~ /^(\*?)([^\(,]*)\(([%\w,]+)\)/) { + $self->{asterisk} = $1; + $self->{label} = $2; + ($self->{base},$self->{index},$self->{scale})=split(/,/,$3); + $self->{scale} = 1 if (!defined($self->{scale})); + $ret = $self; + $line = substr($line,@+[0]); $line =~ s/^\s+//; + + if ($win64 && $self->{label} =~ s/\@GOTPCREL//) { + die if (opcode->mnemonic() ne "mov"); + opcode->mnemonic("lea"); + } + $self->{base} =~ s/^%//; + $self->{index} =~ s/^%// if (defined($self->{index})); + } + $ret; + } + sub size {} + sub out { + my $self = shift; + my $sz = shift; + + $self->{label} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; + $self->{label} =~ s/\.L/$decor/g; + + # Silently convert all EAs to 64-bit. This is required for + # elder GNU assembler and results in more compact code, + # *but* most importantly AES module depends on this feature! + $self->{index} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; + $self->{base} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; + + if ($gas) { + # Solaris /usr/ccs/bin/as can't handle multiplications + # in $self->{label}, new gas requires sign extension... + use integer; + $self->{label} =~ s/(?<![0-9a-f])(0[x0-9a-f]+)/oct($1)/egi; + $self->{label} =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg; + $self->{label} =~ s/([0-9]+)/$1<<32>>32/eg; + $self->{label} =~ s/^___imp_/__imp__/ if ($flavour eq "mingw64"); + + if (defined($self->{index})) { + sprintf "%s%s(%%%s,%%%s,%d)",$self->{asterisk}, + $self->{label},$self->{base}, + $self->{index},$self->{scale}; + } else { + sprintf "%s%s(%%%s)", $self->{asterisk},$self->{label},$self->{base}; + } + } else { + %szmap = ( b=>"BYTE$PTR", w=>"WORD$PTR", l=>"DWORD$PTR", q=>"QWORD$PTR" ); + + $self->{label} =~ s/\./\$/g; + $self->{label} =~ s/0x([0-9a-f]+)/0$1h/ig; + $self->{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/); + $sz="q" if ($self->{asterisk}); + + if (defined($self->{index})) { + sprintf "%s[%s%s*%d+%s]",$szmap{$sz}, + $self->{label}?"$self->{label}+":"", + $self->{index},$self->{scale}, + $self->{base}; + } elsif ($self->{base} eq "rip") { + sprintf "%s[%s]",$szmap{$sz},$self->{label}; + } else { + sprintf "%s[%s%s]",$szmap{$sz}, + $self->{label}?"$self->{label}+":"", + $self->{base}; + } + } + } +} +{ package register; # pick up registers, which start with %. + sub re { + my $class = shift; # muliple instances... + my $self = {}; + local *line = shift; + undef $ret; + + # optional * ---vvv--- appears in indirect jmp/call + if ($line =~ /^(\*?)%(\w+)/) { + bless $self,$class; + $self->{asterisk} = $1; + $self->{value} = $2; + $ret = $self; + $line = substr($line,@+[0]); $line =~ s/^\s+//; + } + $ret; + } + sub size { + my $self = shift; + undef $ret; + + if ($self->{value} =~ /^r[\d]+b$/i) { $ret="b"; } + elsif ($self->{value} =~ /^r[\d]+w$/i) { $ret="w"; } + elsif ($self->{value} =~ /^r[\d]+d$/i) { $ret="l"; } + elsif ($self->{value} =~ /^r[\w]+$/i) { $ret="q"; } + elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; } + elsif ($self->{value} =~ /^[\w]{2}l$/i) { $ret="b"; } + elsif ($self->{value} =~ /^[\w]{2}$/i) { $ret="w"; } + elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; } + + $ret; + } + sub out { + my $self = shift; + if ($gas) { sprintf "%s%%%s",$self->{asterisk},$self->{value}; } + else { $self->{value}; } + } +} +{ package label; # pick up labels, which end with : + sub re { + my $self = shift; # single instance is enough... + local *line = shift; + undef $ret; + + if ($line =~ /(^[\.\w]+)\:/) { + $self->{value} = $1; + $ret = $self; + $line = substr($line,@+[0]); $line =~ s/^\s+//; + + $self->{value} =~ s/^\.L/$decor/; + } + $ret; + } + sub out { + my $self = shift; + + if ($gas) { + my $func = ($globals{$self->{value}} or $self->{value}) . ":"; + if ($win64 && + $current_function->{name} eq $self->{value} && + $current_function->{abi} eq "svr4") { + $func .= "\n"; + $func .= " movq %rdi,8(%rsp)\n"; + $func .= " movq %rsi,16(%rsp)\n"; + $func .= " movq %rsp,%rax\n"; + $func .= "${decor}SEH_begin_$current_function->{name}:\n"; + my $narg = $current_function->{narg}; + $narg=6 if (!defined($narg)); + $func .= " movq %rcx,%rdi\n" if ($narg>0); + $func .= " movq %rdx,%rsi\n" if ($narg>1); + $func .= " movq %r8,%rdx\n" if ($narg>2); + $func .= " movq %r9,%rcx\n" if ($narg>3); + $func .= " movq 40(%rsp),%r8\n" if ($narg>4); + $func .= " movq 48(%rsp),%r9\n" if ($narg>5); + } + $func; + } elsif ($self->{value} ne "$current_function->{name}") { + $self->{value} .= ":" if ($masm && $ret!~m/^\$/); + $self->{value} . ":"; + } elsif ($win64 && $current_function->{abi} eq "svr4") { + my $func = "$current_function->{name}" . + ($nasm ? ":" : "\tPROC $current_function->{scope}") . + "\n"; + $func .= " mov QWORD${PTR}[8+rsp],rdi\t;WIN64 prologue\n"; + $func .= " mov QWORD${PTR}[16+rsp],rsi\n"; + $func .= " mov rax,rsp\n"; + $func .= "${decor}SEH_begin_$current_function->{name}:"; + $func .= ":" if ($masm); + $func .= "\n"; + my $narg = $current_function->{narg}; + $narg=6 if (!defined($narg)); + $func .= " mov rdi,rcx\n" if ($narg>0); + $func .= " mov rsi,rdx\n" if ($narg>1); + $func .= " mov rdx,r8\n" if ($narg>2); + $func .= " mov rcx,r9\n" if ($narg>3); + $func .= " mov r8,QWORD${PTR}[40+rsp]\n" if ($narg>4); + $func .= " mov r9,QWORD${PTR}[48+rsp]\n" if ($narg>5); + $func .= "\n"; + } else { + "$current_function->{name}". + ($nasm ? ":" : "\tPROC $current_function->{scope}"); + } + } +} +{ package expr; # pick up expressioins + sub re { + my $self = shift; # single instance is enough... + local *line = shift; + undef $ret; + + if ($line =~ /(^[^,]+)/) { + $self->{value} = $1; + $ret = $self; + $line = substr($line,@+[0]); $line =~ s/^\s+//; + + $self->{value} =~ s/\@PLT// if (!$elf); + $self->{value} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; + $self->{value} =~ s/\.L/$decor/g; + } + $ret; + } + sub out { + my $self = shift; + if ($nasm && opcode->mnemonic()=~m/^j/) { + "NEAR ".$self->{value}; + } else { + $self->{value}; + } + } +} +{ package directive; # pick up directives, which start with . + sub re { + my $self = shift; # single instance is enough... + local *line = shift; + undef $ret; + my $dir; + my %opcode = # lea 2f-1f(%rip),%dst; 1: nop; 2: + ( "%rax"=>0x01058d48, "%rcx"=>0x010d8d48, + "%rdx"=>0x01158d48, "%rbx"=>0x011d8d48, + "%rsp"=>0x01258d48, "%rbp"=>0x012d8d48, + "%rsi"=>0x01358d48, "%rdi"=>0x013d8d48, + "%r8" =>0x01058d4c, "%r9" =>0x010d8d4c, + "%r10"=>0x01158d4c, "%r11"=>0x011d8d4c, + "%r12"=>0x01258d4c, "%r13"=>0x012d8d4c, + "%r14"=>0x01358d4c, "%r15"=>0x013d8d4c ); + + if ($line =~ /^\s*(\.\w+)/) { + $dir = $1; + $ret = $self; + undef $self->{value}; + $line = substr($line,@+[0]); $line =~ s/^\s+//; + + SWITCH: for ($dir) { + /\.picmeup/ && do { if ($line =~ /(%r[\w]+)/i) { + $dir="\t.long"; + $line=sprintf "0x%x,0x90000000",$opcode{$1}; + } + last; + }; + /\.global|\.globl|\.extern/ + && do { $globals{$line} = $prefix . $line; + $line = $globals{$line} if ($prefix); + last; + }; + /\.type/ && do { ($sym,$type,$narg) = split(',',$line); + if ($type eq "\@function") { + undef $current_function; + $current_function->{name} = $sym; + $current_function->{abi} = "svr4"; + $current_function->{narg} = $narg; + $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE"; + } elsif ($type eq "\@abi-omnipotent") { + undef $current_function; + $current_function->{name} = $sym; + $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE"; + } + $line =~ s/\@abi\-omnipotent/\@function/; + $line =~ s/\@function.*/\@function/; + last; + }; + /\.asciz/ && do { if ($line =~ /^"(.*)"$/) { + $dir = ".byte"; + $line = join(",",unpack("C*",$1),0); + } + last; + }; + /\.rva|\.long|\.quad/ + && do { $line =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; + $line =~ s/\.L/$decor/g; + last; + }; + } + + if ($gas) { + $self->{value} = $dir . "\t" . $line; + + if ($dir =~ /\.extern/) { + $self->{value} = ""; # swallow extern + } elsif (!$elf && $dir =~ /\.type/) { + $self->{value} = ""; + $self->{value} = ".def\t" . ($globals{$1} or $1) . ";\t" . + (defined($globals{$1})?".scl 2;":".scl 3;") . + "\t.type 32;\t.endef" + if ($win64 && $line =~ /([^,]+),\@function/); + } elsif (!$elf && $dir =~ /\.size/) { + $self->{value} = ""; + if (defined($current_function)) { + $self->{value} .= "${decor}SEH_end_$current_function->{name}:" + if ($win64 && $current_function->{abi} eq "svr4"); + undef $current_function; + } + } elsif (!$elf && $dir =~ /\.align/) { + $self->{value} = ".p2align\t" . (log($line)/log(2)); + } elsif ($dir eq ".section") { + $current_segment=$line; + if (!$elf && $current_segment eq ".init") { + if ($flavour eq "macosx") { $self->{value} = ".mod_init_func"; } + elsif ($flavour eq "mingw64") { $self->{value} = ".section\t.ctors"; } + } + } elsif ($dir =~ /\.(text|data)/) { + $current_segment=".$1"; + } + $line = ""; + return $self; + } + + # non-gas case or nasm/masm + SWITCH: for ($dir) { + /\.text/ && do { my $v=undef; + if ($nasm) { + $v="section .text code align=64\n"; + } else { + $v="$current_segment\tENDS\n" if ($current_segment); + $current_segment = ".text\$"; + $v.="$current_segment\tSEGMENT "; + $v.=$masm>=$masmref ? "ALIGN(64)" : "PAGE"; + $v.=" 'CODE'"; + } + $self->{value} = $v; + last; + }; + /\.data/ && do { my $v=undef; + if ($nasm) { + $v="section .data data align=8\n"; + } else { + $v="$current_segment\tENDS\n" if ($current_segment); + $current_segment = "_DATA"; + $v.="$current_segment\tSEGMENT"; + } + $self->{value} = $v; + last; + }; + /\.section/ && do { my $v=undef; + $line =~ s/([^,]*).*/$1/; + $line = ".CRT\$XCU" if ($line eq ".init"); + if ($nasm) { + $v="section $line"; + if ($line=~/\.([px])data/) { + $v.=" rdata align="; + $v.=$1 eq "p"? 4 : 8; + } + } else { + $v="$current_segment\tENDS\n" if ($current_segment); + $v.="$line\tSEGMENT"; + if ($line=~/\.([px])data/) { + $v.=" READONLY"; + $v.=" ALIGN(".($1 eq "p" ? 4 : 8).")" if ($masm>=$masmref); + } + } + $current_segment = $line; + $self->{value} = $v; + last; + }; + /\.extern/ && do { $self->{value} = "EXTERN\t".$line; + $self->{value} .= ":NEAR" if ($masm); + last; + }; + /\.globl|.global/ + && do { $self->{value} = $masm?"PUBLIC":"global"; + $self->{value} .= "\t".$line; + last; + }; + /\.size/ && do { if (defined($current_function)) { + undef $self->{value}; + if ($current_function->{abi} eq "svr4") { + $self->{value}="${decor}SEH_end_$current_function->{name}:"; + $self->{value}.=":\n" if($masm); + } + $self->{value}.="$current_function->{name}\tENDP" if($masm); + undef $current_function; + } + last; + }; + /\.align/ && do { $self->{value} = "ALIGN\t".$line; last; }; + /\.(value|long|rva|quad)/ + && do { my $sz = substr($1,0,1); + my @arr = split(',',$line); + my $last = pop(@arr); + my $conv = sub { my $var=shift; + $var=~s/^(0b[0-1]+)/oct($1)/eig; + $var=~s/^0x([0-9a-f]+)/0$1h/ig if ($masm); + if ($sz eq "D" && ($current_segment=~/.[px]data/ || $dir eq ".rva")) + { $var=~s/([_a-z\$\@][_a-z0-9\$\@]*)/$nasm?"$1 wrt ..imagebase":"imagerel $1"/egi; } + $var; + }; + + $sz =~ tr/bvlrq/BWDDQ/; + $self->{value} = "\tD$sz\t"; + for (@arr) { $self->{value} .= &$conv($_).","; } + $self->{value} .= &$conv($last); + last; + }; + /\.byte/ && do { my @str=split(",",$line); + map(s/(0b[0-1]+)/oct($1)/eig,@str); + map(s/0x([0-9a-f]+)/0$1h/ig,@str) if ($masm); + while ($#str>15) { + $self->{value}.="DB\t" + .join(",",@str[0..15])."\n"; + foreach (0..15) { shift @str; } + } + $self->{value}.="DB\t" + .join(",",@str) if (@str); + last; + }; + } + $line = ""; + } + + $ret; + } + sub out { + my $self = shift; + $self->{value}; + } +} + +if ($nasm) { + print <<___; +default rel +___ +} elsif ($masm) { + print <<___; +OPTION DOTNAME +___ +} +while($line=<>) { + + chomp($line); + + $line =~ s|[#!].*$||; # get rid of asm-style comments... + $line =~ s|/\*.*\*/||; # ... and C-style comments... + $line =~ s|^\s+||; # ... and skip white spaces in beginning + + undef $label; + undef $opcode; + undef $sz; + undef @args; + + if ($label=label->re(\$line)) { print $label->out(); } + + if (directive->re(\$line)) { + printf "%s",directive->out(); + } elsif ($opcode=opcode->re(\$line)) { ARGUMENT: while (1) { + my $arg; + + if ($arg=register->re(\$line)) { opcode->size($arg->size()); } + elsif ($arg=const->re(\$line)) { } + elsif ($arg=ea->re(\$line)) { } + elsif ($arg=expr->re(\$line)) { } + else { last ARGUMENT; } + + push @args,$arg; + + last ARGUMENT if ($line !~ /^,/); + + $line =~ s/^,\s*//; + } # ARGUMENT: + + $sz=opcode->size(); + + if ($#args>=0) { + my $insn; + if ($gas) { + $insn = $opcode->out($#args>=1?$args[$#args]->size():$sz); + } else { + $insn = $opcode->out(); + $insn .= $sz if (map($_->out() =~ /xmm|mmx/,@args)); + @args = reverse(@args); + undef $sz if ($nasm && $opcode->mnemonic() eq "lea"); + } + printf "\t%s\t%s",$insn,join(",",map($_->out($sz),@args)); + } else { + printf "\t%s",$opcode->out(); + } + } + + print $line,"\n"; +} + +print "\n$current_segment\tENDS\n" if ($current_segment && $masm); +print "END\n" if ($masm); + +close STDOUT; + + ################################################# +# Cross-reference x86_64 ABI "card" +# +# Unix Win64 +# %rax * * +# %rbx - - +# %rcx #4 #1 +# %rdx #3 #2 +# %rsi #2 - +# %rdi #1 - +# %rbp - - +# %rsp - - +# %r8 #5 #3 +# %r9 #6 #4 +# %r10 * * +# %r11 * * +# %r12 - - +# %r13 - - +# %r14 - - +# %r15 - - +# +# (*) volatile register +# (-) preserved by callee +# (#) Nth argument, volatile +# +# In Unix terms top of stack is argument transfer area for arguments +# which could not be accomodated in registers. Or in other words 7th +# [integer] argument resides at 8(%rsp) upon function entry point. +# 128 bytes above %rsp constitute a "red zone" which is not touched +# by signal handlers and can be used as temporal storage without +# allocating a frame. +# +# In Win64 terms N*8 bytes on top of stack is argument transfer area, +# which belongs to/can be overwritten by callee. N is the number of +# arguments passed to callee, *but* not less than 4! This means that +# upon function entry point 5th argument resides at 40(%rsp), as well +# as that 32 bytes from 8(%rsp) can always be used as temporal +# storage [without allocating a frame]. One can actually argue that +# one can assume a "red zone" above stack pointer under Win64 as well. +# Point is that at apparently no occasion Windows kernel would alter +# the area above user stack pointer in true asynchronous manner... +# +# All the above means that if assembler programmer adheres to Unix +# register and stack layout, but disregards the "red zone" existense, +# it's possible to use following prologue and epilogue to "gear" from +# Unix to Win64 ABI in leaf functions with not more than 6 arguments. +# +# omnipotent_function: +# ifdef WIN64 +# movq %rdi,8(%rsp) +# movq %rsi,16(%rsp) +# movq %rcx,%rdi ; if 1st argument is actually present +# movq %rdx,%rsi ; if 2nd argument is actually ... +# movq %r8,%rdx ; if 3rd argument is ... +# movq %r9,%rcx ; if 4th argument ... +# movq 40(%rsp),%r8 ; if 5th ... +# movq 48(%rsp),%r9 ; if 6th ... +# endif +# ... +# ifdef WIN64 +# movq 8(%rsp),%rdi +# movq 16(%rsp),%rsi +# endif +# ret +# + ################################################# +# Win64 SEH, Structured Exception Handling. +# +# Unlike on Unix systems(*) lack of Win64 stack unwinding information +# has undesired side-effect at run-time: if an exception is raised in +# assembler subroutine such as those in question (basically we're +# referring to segmentation violations caused by malformed input +# parameters), the application is briskly terminated without invoking +# any exception handlers, most notably without generating memory dump +# or any user notification whatsoever. This poses a problem. It's +# possible to address it by registering custom language-specific +# handler that would restore processor context to the state at +# subroutine entry point and return "exception is not handled, keep +# unwinding" code. Writing such handler can be a challenge... But it's +# doable, though requires certain coding convention. Consider following +# snippet: +# +# .type function,@function +# function: +# movq %rsp,%rax # copy rsp to volatile register +# pushq %r15 # save non-volatile registers +# pushq %rbx +# pushq %rbp +# movq %rsp,%r11 +# subq %rdi,%r11 # prepare [variable] stack frame +# andq $-64,%r11 +# movq %rax,0(%r11) # check for exceptions +# movq %r11,%rsp # allocate [variable] stack frame +# movq %rax,0(%rsp) # save original rsp value +# magic_point: +# ... +# movq 0(%rsp),%rcx # pull original rsp value +# movq -24(%rcx),%rbp # restore non-volatile registers +# movq -16(%rcx),%rbx +# movq -8(%rcx),%r15 +# movq %rcx,%rsp # restore original rsp +# ret +# .size function,.-function +# +# The key is that up to magic_point copy of original rsp value remains +# in chosen volatile register and no non-volatile register, except for +# rsp, is modified. While past magic_point rsp remains constant till +# the very end of the function. In this case custom language-specific +# exception handler would look like this: +# +# EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame, +# CONTEXT *context,DISPATCHER_CONTEXT *disp) +# { ULONG64 *rsp = (ULONG64 *)context->Rax; +# if (context->Rip >= magic_point) +# { rsp = ((ULONG64 **)context->Rsp)[0]; +# context->Rbp = rsp[-3]; +# context->Rbx = rsp[-2]; +# context->R15 = rsp[-1]; +# } +# context->Rsp = (ULONG64)rsp; +# context->Rdi = rsp[1]; +# context->Rsi = rsp[2]; +# +# memcpy (disp->ContextRecord,context,sizeof(CONTEXT)); +# RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase, +# dips->ControlPc,disp->FunctionEntry,disp->ContextRecord, +# &disp->HandlerData,&disp->EstablisherFrame,NULL); +# return ExceptionContinueSearch; +# } +# +# It's appropriate to implement this handler in assembler, directly in +# function's module. In order to do that one has to know members' +# offsets in CONTEXT and DISPATCHER_CONTEXT structures and some constant +# values. Here they are: +# +# CONTEXT.Rax 120 +# CONTEXT.Rcx 128 +# CONTEXT.Rdx 136 +# CONTEXT.Rbx 144 +# CONTEXT.Rsp 152 +# CONTEXT.Rbp 160 +# CONTEXT.Rsi 168 +# CONTEXT.Rdi 176 +# CONTEXT.R8 184 +# CONTEXT.R9 192 +# CONTEXT.R10 200 +# CONTEXT.R11 208 +# CONTEXT.R12 216 +# CONTEXT.R13 224 +# CONTEXT.R14 232 +# CONTEXT.R15 240 +# CONTEXT.Rip 248 +# CONTEXT.Xmm6 512 +# sizeof(CONTEXT) 1232 +# DISPATCHER_CONTEXT.ControlPc 0 +# DISPATCHER_CONTEXT.ImageBase 8 +# DISPATCHER_CONTEXT.FunctionEntry 16 +# DISPATCHER_CONTEXT.EstablisherFrame 24 +# DISPATCHER_CONTEXT.TargetIp 32 +# DISPATCHER_CONTEXT.ContextRecord 40 +# DISPATCHER_CONTEXT.LanguageHandler 48 +# DISPATCHER_CONTEXT.HandlerData 56 +# UNW_FLAG_NHANDLER 0 +# ExceptionContinueSearch 1 +# +# In order to tie the handler to the function one has to compose +# couple of structures: one for .xdata segment and one for .pdata. +# +# UNWIND_INFO structure for .xdata segment would be +# +# function_unwind_info: +# .byte 9,0,0,0 +# .rva handler +# +# This structure designates exception handler for a function with +# zero-length prologue, no stack frame or frame register. +# +# To facilitate composing of .pdata structures, auto-generated "gear" +# prologue copies rsp value to rax and denotes next instruction with +# .LSEH_begin_{function_name} label. This essentially defines the SEH +# styling rule mentioned in the beginning. Position of this label is +# chosen in such manner that possible exceptions raised in the "gear" +# prologue would be accounted to caller and unwound from latter's frame. +# End of function is marked with respective .LSEH_end_{function_name} +# label. To summarize, .pdata segment would contain +# +# .rva .LSEH_begin_function +# .rva .LSEH_end_function +# .rva function_unwind_info +# +# Reference to functon_unwind_info from .xdata segment is the anchor. +# In case you wonder why references are 32-bit .rvas and not 64-bit +# .quads. References put into these two segments are required to be +# *relative* to the base address of the current binary module, a.k.a. +# image base. No Win64 module, be it .exe or .dll, can be larger than +# 2GB and thus such relative references can be and are accommodated in +# 32 bits. +# +# Having reviewed the example function code, one can argue that "movq +# %rsp,%rax" above is redundant. It is not! Keep in mind that on Unix +# rax would contain an undefined value. If this "offends" you, use +# another register and refrain from modifying rax till magic_point is +# reached, i.e. as if it was a non-volatile register. If more registers +# are required prior [variable] frame setup is completed, note that +# nobody says that you can have only one "magic point." You can +# "liberate" non-volatile registers by denoting last stack off-load +# instruction and reflecting it in finer grade unwind logic in handler. +# After all, isn't it why it's called *language-specific* handler... +# +# Attentive reader can notice that exceptions would be mishandled in +# auto-generated "gear" epilogue. Well, exception effectively can't +# occur there, because if memory area used by it was subject to +# segmentation violation, then it would be raised upon call to the +# function (and as already mentioned be accounted to caller, which is +# not a problem). If you're still not comfortable, then define tail +# "magic point" just prior ret instruction and have handler treat it... +# +# (*) Note that we're talking about run-time, not debug-time. Lack of +# unwind information makes debugging hard on both Windows and +# Unix. "Unlike" referes to the fact that on Unix signal handler +# will always be invoked, core dumped and appropriate exit code +# returned to parent (for user notification). |