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x86_64-xlate.pl
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#!/usr/bin/env perl
#
# Copyright Supranational LLC
# Licensed under the Apache License, Version 2.0, see LICENSE for details.
# SPDX-License-Identifier: Apache-2.0
#
# Ascetic x86_64 AT&T to MASM/NASM assembler translator by @dot-asm.
#
# 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.
#
# 8. In order to provide for structured exception handling unified
# Win64 prologue copies %rsp value to %rax. [Unless function is
# tagged with additional .type tag.] For further details see SEH
# paragraph at the end.
# 9. .init segment is allowed to contain calls to functions only.
# a. If function accepts more than 4 arguments *and* >4th argument
# is declared as non 64-bit value, do clear its upper part.
use strict;
my $flavour = shift;
my $output = shift;
if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
open STDOUT,">$output" || die "can't open $output: $!"
if (defined($output));
my $gas=1; $gas=0 if ($output =~ /\.asm$/);
my $elf=1; $elf=0 if (!$gas);
my $dwarf=$elf;
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=`echo __USER_LABEL_PREFIX__ | \${CC:-false} -E -P -`;
$prefix =~ s|\R$||; # Better chomp
}
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 $colon= $masm ? "::" : ":";
$dwarf=0 if($win64);
my $current_segment;
my $current_function;
my %globals;
my $ret_clobber;
{ package opcode; # pick up opcodes
sub re {
my ($class, $line) = @_;
my $self = {};
my $ret;
if ($$line =~ /^([a-z][a-z0-9]*)/i) {
bless $self,$class;
$self->{op} = $1;
$ret = $self;
$$line = substr($$line,@+[0]); $$line =~ s/^\s+//;
undef $self->{sz};
if ($self->{op} =~ /^(movz)x?([bw]).*/) { # movz is pain...
$self->{op} = $1;
$self->{sz} = $2;
} elsif ($self->{op} =~ /cmov[n]?[lb]$/) {
# pass through
} elsif ($self->{op} =~ /call|jmp/) {
$self->{sz} = "";
} elsif ($self->{op} =~ /^p/ && $' !~ /^(ush|op|insrw)/) { # SSEn
$self->{sz} = "";
} elsif ($self->{op} =~ /^[vk]/) { # VEX or k* such as kmov
$self->{sz} = "";
} elsif ($self->{op} =~ /mov[dq]/ && $$line =~ /%xmm/) {
$self->{sz} = "";
} elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) {
$self->{op} = $1;
$self->{sz} = $2;
}
}
$ret;
}
sub size {
my ($self, $sz) = @_;
$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 = "";
my $reg = $ret_clobber || "rdx";
$ret_clobber = undef;
if ($win64 && $current_function->{abi} eq "svr4"
&& !$current_function->{unwind}) {
$epilogue = "movq 8(%rsp),%rdi\n\t" .
"movq 16(%rsp),%rsi\n\t";
}
$epilogue . "\n#ifdef __SGX_LVI_HARDENING__\n".
" popq %$reg\n" .
" lfence\n" .
" jmpq *%$reg\n" .
" ud2\n" .
"#else\n" .
" .byte 0xf3,0xc3\n" .
"#endif";
} elsif ($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} = "";
my $reg = $ret_clobber || "rdx";
$ret_clobber = undef;
if ($win64 && $current_function->{abi} eq "svr4"
&& !$current_function->{unwind}) {
$self->{op} = "mov rdi,QWORD$PTR\[8+rsp\]\t;WIN64 epilogue\n\t".
"mov rsi,QWORD$PTR\[16+rsp\]\n\t";
}
$self->{op} .= "\nifdef __SGX_LVI_HARDENING__\n".
" pop $reg\n" .
" lfence\n" .
" jmp $reg\n" .
" ud2\n" .
"else\n" .
" DB\t0F3h,0C3h\n" .
"endif";
} elsif ($self->{op} =~ /^(pop|push)f/) {
$self->{op} .= $self->{sz};
} elsif ($self->{op} eq "call" && $current_segment eq ".CRT\$XCU") {
$self->{op} = "\tDQ";
}
$self->{op};
}
}
sub mnemonic {
my ($self, $op) = @_;
$self->{op}=$op if (defined($op));
$self->{op};
}
}
{ package const; # pick up constants, which start with $
sub re {
my ($class, $line) = @_;
my $self = {};
my $ret;
if ($$line =~ /^\$([^,]+)/) {
bless $self, $class;
$self->{value} = $1;
$ret = $self;
$$line = substr($$line,@+[0]); $$line =~ s/^\s+//;
}
$ret;
}
sub out {
my $self = shift;
$self->{value} =~ s/\b(0b[0-1]+)/oct($1)/eig;
if ($gas) {
# Solaris /usr/ccs/bin/as can't handle multiplications
# in $self->{value}
my $value = $self->{value};
no warnings; # oct might complain about overflow, ignore here...
$value =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi;
if ($value =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg) {
$self->{value} = $value;
}
sprintf "\$%s",$self->{value};
} else {
my $value = $self->{value};
$value =~ s/0x([0-9a-f]+)/0$1h/ig if ($masm);
sprintf "%s",$value;
}
}
}
{ package ea; # pick up effective addresses: expr(%reg,%reg,scale)
my %szmap = ( b=>"BYTE$PTR", w=>"WORD$PTR",
l=>"DWORD$PTR", d=>"DWORD$PTR",
q=>"QWORD$PTR", o=>"OWORD$PTR",
x=>"XMMWORD$PTR", y=>"YMMWORD$PTR",
z=>"ZMMWORD$PTR" ) if (!$gas);
my %sifmap = ( ss=>"d", sd=>"q", # broadcast only
i32x2=>"q", f32x2=>"q",
i32x4=>"x", i64x2=>"x", i128=>"x",
f32x4=>"x", f64x2=>"x", f128=>"x",
i32x8=>"y", i64x4=>"y",
f32x8=>"y", f64x4=>"y" ) if (!$gas);
sub re {
my ($class, $line, $opcode) = @_;
my $self = {};
my $ret;
# optional * ----vvv--- appears in indirect jmp/call
if ($$line =~ /^(\*?)([^\(,]*)\(([%\w,\s]+)\)((?:{[^}]+})*)/) {
bless $self, $class;
$self->{asterisk} = $1;
$self->{label} = $2;
($self->{base},$self->{index},$self->{scale})=split(/(?:,\s*)/,$3);
$self->{scale} = 1 if (!defined($self->{scale}));
$self->{opmask} = $4;
$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}));
$self->{opcode} = $opcode;
}
$ret;
}
sub size {}
sub out {
my ($self, $sz) = @_;
$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/;
# Solaris /usr/ccs/bin/as can't handle multiplications
# in $self->{label}...
use integer;
$self->{label} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi;
$self->{label} =~ s/\b([0-9]+\s*[\*\/\%]\s*[0-9]+)\b/eval($1)/eg;
# Some assemblers insist on signed presentation of 32-bit
# offsets, but sign extension is a tricky business in perl...
$self->{label} =~ s/\b([0-9]+)\b/unpack("l",pack("L",$1))/eg;
# if base register is %rbp or %r13, see if it's possible to
# flip base and index registers [for better performance]
if (!$self->{label} && $self->{index} && $self->{scale}==1 &&
$self->{base} =~ /(rbp|r13)/) {
$self->{base} = $self->{index}; $self->{index} = $1;
}
if ($gas) {
$self->{label} =~ s/^___imp_/__imp__/ if ($flavour eq "mingw64");
if (defined($self->{index})) {
sprintf "%s%s(%s,%%%s,%d)%s",
$self->{asterisk},$self->{label},
$self->{base}?"%$self->{base}":"",
$self->{index},$self->{scale},
$self->{opmask};
} else {
sprintf "%s%s(%%%s)%s", $self->{asterisk},$self->{label},
$self->{base},$self->{opmask};
}
} else {
$self->{label} =~ s/\./\$/g;
$self->{label} =~ s/(?<![\w\$\.])0x([0-9a-f]+)/0$1h/ig;
$self->{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/);
my $mnemonic = $self->{opcode}->mnemonic();
($self->{asterisk}) && ($sz="q") ||
($mnemonic =~ /^v?mov([qd])$/) && ($sz=$1) ||
($mnemonic =~ /^v?pinsr([qdwb])$/) && ($sz=$1) ||
($mnemonic =~ /^vpbroadcast([qdwb])$/) && ($sz=$1) ||
($mnemonic =~ /^v(?:broadcast|extract|insert)([sif]\w+)$/)
&& ($sz=$sifmap{$1});
$self->{opmask} =~ s/%(k[0-7])/$1/;
if (defined($self->{index})) {
sprintf "%s[%s%s*%d%s]%s",$szmap{$sz},
$self->{label}?"$self->{label}+":"",
$self->{index},$self->{scale},
$self->{base}?"+$self->{base}":"",
$self->{opmask};
} elsif ($self->{base} eq "rip") {
sprintf "%s[%s]",$szmap{$sz},$self->{label};
} else {
sprintf "%s[%s%s]%s", $szmap{$sz},
$self->{label}?"$self->{label}+":"",
$self->{base},$self->{opmask};
}
}
}
}
{ package register; # pick up registers, which start with %.
sub re {
my ($class, $line, $opcode) = @_;
my $self = {};
my $ret;
# optional * ----vvv--- appears in indirect jmp/call
if ($$line =~ /^(\*?)%(\w+)((?:{[^}]+})*)/) {
bless $self,$class;
$self->{asterisk} = $1;
$self->{value} = $2;
$self->{opmask} = $3;
$opcode->size($self->size());
$ret = $self;
$$line = substr($$line,@+[0]); $$line =~ s/^\s+//;
}
$ret;
}
sub size {
my $self = shift;
my $ret;
if ($self->{value} =~ /^r[\d]+b$/i) { $ret="b"; }
elsif ($self->{value} =~ /^r[\d]+w$/i) { $ret="w"; }
elsif ($self->{value} =~ /^r[\d]+d$/i) { $ret="l"; }
elsif ($self->{value} =~ /^r[\w]+$/i) { $ret="q"; }
elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; }
elsif ($self->{value} =~ /^[\w]{2}l$/i) { $ret="b"; }
elsif ($self->{value} =~ /^[\w]{2}$/i) { $ret="w"; }
elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; }
$ret;
}
sub out {
my $self = shift;
if ($gas) { sprintf "%s%%%s%s", $self->{asterisk},
$self->{value},
$self->{opmask}; }
else { $self->{opmask} =~ s/%(k[0-7])/$1/;
$self->{value}.$self->{opmask}; }
}
}
{ package label; # pick up labels, which end with :
sub re {
my ($class, $line) = @_;
my $self = {};
my $ret;
if ($$line =~ /(^[\.\w\$]+)\:/) {
bless $self,$class;
$self->{value} = $1;
$ret = $self;
$$line = substr($$line,@+[0]); $$line =~ s/^\s+//;
$self->{value} =~ s/^\.L/$decor/;
}
$ret;
}
sub win64_args {
my $narg = $current_function->{narg} // 6;
return undef if ($narg < 0);
my $arg5 = 4*8 - cfi_directive::cfa_rsp();
my $arg6 = $arg5 + 8;
my $args;
if ($gas) {
$args .= " movq %rcx,%rdi\n" if ($narg>0);
$args .= " movq %rdx,%rsi\n" if ($narg>1);
$args .= " movq %r8,%rdx\n" if ($narg>2);
$args .= " movq %r9,%rcx\n" if ($narg>3);
$args .= " movq $arg5(%rsp),%r8\n" if ($narg>4);
$args .= " movq $arg6(%rsp),%r9\n" if ($narg>5);
} else {
$args .= " mov rdi,rcx\n" if ($narg>0);
$args .= " mov rsi,rdx\n" if ($narg>1);
$args .= " mov rdx,r8\n" if ($narg>2);
$args .= " mov rcx,r9\n" if ($narg>3);
$args .= " mov r8,QWORD$PTR\[$arg5+rsp\]\n" if ($narg>4);
$args .= " mov r9,QWORD$PTR\[$arg6+rsp\]\n" if ($narg>5);
}
$current_function->{narg} = -1;
$args;
}
sub out {
my $self = shift;
if ($gas) {
my $func = ($globals{$self->{value}} or $self->{value}) . ":";
if ($current_function->{name} eq $self->{value}) {
$current_function->{pc} = 0;
$func .= "\n.cfi_".cfi_directive::startproc() if ($dwarf);
$func .= "\n .byte 0xf3,0x0f,0x1e,0xfa\n"; # endbranch
if ($win64) {
if ($current_function->{abi} eq "svr4") {
my $fp = $current_function->{unwind} ? "%r11" : "%rax";
$func .= " movq %rdi,8(%rsp)\n";
$func .= " movq %rsi,16(%rsp)\n";
$func .= " movq %rsp,$fp\n";
$func .= "${decor}SEH_begin_$current_function->{name}:\n";
} elsif ($current_function->{unwind}) {
$func .= " movq %rsp,%r11\n";
$func .= "${decor}SEH_begin_$current_function->{name}:\n";
}
}
} elsif ($win64 && $current_function->{abi} eq "svr4"
&& $current_function->{pc} >= 0) {
$func = win64_args().$func;
}
$func;
} elsif ($self->{value} ne "$current_function->{name}") {
my $func;
if ($win64 && $current_function->{abi} eq "svr4"
&& $current_function->{pc} >= 0) {
$func = win64_args();
}
$func .= $self->{value} . $colon;
$func;
} else {
$current_function->{pc} = 0;
my $func = "$current_function->{name}" .
($nasm ? ":" : "\tPROC $current_function->{scope}") .
"\n";
$func .= " DB 243,15,30,250\n"; # endbranch
if ($current_function->{abi} eq "svr4") {
my $fp = $current_function->{unwind} ? "r11" : "rax";
$func .= " mov QWORD$PTR\[8+rsp\],rdi\t;WIN64 prologue\n";
$func .= " mov QWORD$PTR\[16+rsp\],rsi\n";
$func .= " mov $fp,rsp\n";
$func .= "${decor}SEH_begin_$current_function->{name}${colon}\n";
} elsif ($current_function->{unwind}) {
$func .= " mov r11,rsp\n";
$func .= "${decor}SEH_begin_$current_function->{name}${colon}\n";
}
$func;
}
}
}
{ package expr; # pick up expressions
sub re {
my ($class, $line, $opcode) = @_;
my $self = {};
my $ret;
if ($$line =~ /(^[^,]+)/) {
bless $self,$class;
$self->{value} = $1;
$ret = $self;
$$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;
$self->{opcode} = $opcode;
}
$ret;
}
sub out {
my $self = shift;
$self->{value};
}
}
my @xdata_seg = (".section .xdata", ".align 8");
my @pdata_seg = (".section .pdata", ".align 4");
{ package cfi_directive;
# CFI directives annotate instructions that are significant for
# stack unwinding procedure compliant with DWARF specification,
# see http://dwarfstd.org/. Besides naturally expected for this
# script platform-specific filtering function, this module adds
# four auxiliary synthetic directives not recognized by [GNU]
# assembler:
#
# - .cfi_push to annotate push instructions in prologue, which
# translates to .cfi_adjust_cfa_offset (if needed) and
# .cfi_offset;
# - .cfi_pop to annotate pop instructions in epilogue, which
# translates to .cfi_adjust_cfa_offset (if needed) and
# .cfi_restore;
# - .cfi_alloca to annotate stack pointer adjustments, which
# translates to .cfi_adjust_cfa_offset as needed;
# - [and most notably] .cfi_cfa_expression which encodes
# DW_CFA_def_cfa_expression and passes it to .cfi_escape as
# byte vector;
#
# CFA expressions were introduced in DWARF specification version
# 3 and describe how to deduce CFA, Canonical Frame Address. This
# becomes handy if your stack frame is variable and you can't
# spare register for [previous] frame pointer. Suggested directive
# syntax is made-up mix of DWARF operator suffixes [subset of]
# and references to registers with optional bias. Following example
# describes offloaded *original* stack pointer at specific offset
# from *current* stack pointer:
#
# .cfi_cfa_expression %rsp+40,deref,+8
#
# Final +8 has everything to do with the fact that CFA is defined
# as reference to top of caller's stack, and on x86_64 call to
# subroutine pushes 8-byte return address. In other words original
# stack pointer upon entry to a subroutine is 8 bytes off from CFA.
#
# In addition the .cfi directives are re-purposed even for Win64
# stack unwinding. Two more synthetic directives were added:
#
# - .cfi_end_prologue to denote point when all non-volatile
# registers are saved and stack or [chosen] frame pointer is
# stable;
# - .cfi_epilogue to denote point when all non-volatile registers
# are restored [and it even adds missing .cfi_restore-s];
#
# Though it's not universal "miracle cure," it has its limitations.
# Most notably .cfi_cfa_expression won't start working... For more
# information see the end of this file.
# Below constants are taken from "DWARF Expressions" section of the
# DWARF specification, section is numbered 7.7 in versions 3 and 4.
my %DW_OP_simple = ( # no-arg operators, mapped directly
deref => 0x06, dup => 0x12,
drop => 0x13, over => 0x14,
pick => 0x15, swap => 0x16,
rot => 0x17, xderef => 0x18,
abs => 0x19, and => 0x1a,
div => 0x1b, minus => 0x1c,
mod => 0x1d, mul => 0x1e,
neg => 0x1f, not => 0x20,
or => 0x21, plus => 0x22,
shl => 0x24, shr => 0x25,
shra => 0x26, xor => 0x27,
);
my %DW_OP_complex = ( # used in specific subroutines
constu => 0x10, # uleb128
consts => 0x11, # sleb128
plus_uconst => 0x23, # uleb128
lit0 => 0x30, # add 0-31 to opcode
reg0 => 0x50, # add 0-31 to opcode
breg0 => 0x70, # add 0-31 to opcole, sleb128
regx => 0x90, # uleb28
fbreg => 0x91, # sleb128
bregx => 0x92, # uleb128, sleb128
piece => 0x93, # uleb128
);
# Following constants are defined in x86_64 ABI supplement, for
# example available at https://www.uclibc.org/docs/psABI-x86_64.pdf,
# see section 3.7 "Stack Unwind Algorithm".
my %DW_reg_idx = (
"%rax"=>0, "%rdx"=>1, "%rcx"=>2, "%rbx"=>3,
"%rsi"=>4, "%rdi"=>5, "%rbp"=>6, "%rsp"=>7,
"%r8" =>8, "%r9" =>9, "%r10"=>10, "%r11"=>11,
"%r12"=>12, "%r13"=>13, "%r14"=>14, "%r15"=>15
);
my ($cfa_reg, $cfa_off, $cfa_rsp, %saved_regs);
my @cfa_stack;
sub cfa_rsp { return $cfa_rsp // -8; }
# [us]leb128 format is variable-length integer representation base
# 2^128, with most significant bit of each byte being 0 denoting
# *last* most significant digit. See "Variable Length Data" in the
# DWARF specification, numbered 7.6 at least in versions 3 and 4.
sub sleb128 {
use integer; # get right shift extend sign
my $val = shift;
my $sign = ($val < 0) ? -1 : 0;
my @ret = ();
while(1) {
push @ret, $val&0x7f;
# see if remaining bits are same and equal to most
# significant bit of the current digit, if so, it's
# last digit...
last if (($val>>6) == $sign);
@ret[-1] |= 0x80;
$val >>= 7;
}
return @ret;
}
sub uleb128 {
my $val = shift;
my @ret = ();
while(1) {
push @ret, $val&0x7f;
# see if it's last significant digit...
last if (($val >>= 7) == 0);
@ret[-1] |= 0x80;
}
return @ret;
}
sub const {
my $val = shift;
if ($val >= 0 && $val < 32) {
return ($DW_OP_complex{lit0}+$val);
}
return ($DW_OP_complex{consts}, sleb128($val));
}
sub reg {
my $val = shift;
return if ($val !~ m/^(%r\w+)(?:([\+\-])((?:0x)?[0-9a-f]+))?/);
my $reg = $DW_reg_idx{$1};
my $off = eval ("0 $2 $3");
return (($DW_OP_complex{breg0} + $reg), sleb128($off));
# Yes, we use DW_OP_bregX+0 to push register value and not
# DW_OP_regX, because latter would require even DW_OP_piece,
# which would be a waste under the circumstances. If you have
# to use DWP_OP_reg, use "regx:N"...
}
sub cfa_expression {
my $line = shift;
my @ret;
foreach my $token (split(/,\s*/,$line)) {
if ($token =~ /^%r/) {
push @ret,reg($token);
} elsif ($token =~ /((?:0x)?[0-9a-f]+)\((%r\w+)\)/) {
push @ret,reg("$2+$1");
} elsif ($token =~ /(\w+):(\-?(?:0x)?[0-9a-f]+)(U?)/i) {
my $i = 1*eval($2);
push @ret,$DW_OP_complex{$1}, ($3 ? uleb128($i) : sleb128($i));
} elsif (my $i = 1*eval($token) or $token eq "0") {
if ($token =~ /^\+/) {
push @ret,$DW_OP_complex{plus_uconst},uleb128($i);
} else {
push @ret,const($i);
}
} else {
push @ret,$DW_OP_simple{$token};
}
}
# Finally we return DW_CFA_def_cfa_expression, 15, followed by
# length of the expression and of course the expression itself.
return (15,scalar(@ret),@ret);
}
# Following constants are defined in "x64 exception handling" at
# https://docs.microsoft.com/ and match the register sequence in
# CONTEXT structure defined in winnt.h.
my %WIN64_reg_idx = (
"%rax"=>0, "%rcx"=>1, "%rdx"=>2, "%rbx"=>3,
"%rsp"=>4, "%rbp"=>5, "%rsi"=>6, "%rdi"=>7,
"%r8" =>8, "%r9" =>9, "%r10"=>10, "%r11"=>11,
"%r12"=>12, "%r13"=>13, "%r14"=>14, "%r15"=>15
);
sub xdata {
our @dat = ();
our $len = 0;
sub savereg {
my ($key, $offset) = @_;
if ($key =~ /%xmm([0-9]+)/) {
if ($offset < 0x100000) {
push @dat, [0,($1<<4)|8,unpack("C2",pack("v",$offset>>4))];
} else {
push @dat, [0,($1<<4)|9,unpack("C4",pack("V",$offset))];
}
} else {
if ($offset < 0x80000) {
push @dat, [0,(($WIN64_reg_idx{$key})<<4)|4,
unpack("C2",pack("v",$offset>>3))];
} else {
push @dat, [0,(($WIN64_reg_idx{$key})<<4)|5,
unpack("C4",pack("V",$offset))];
}
}
$len += $#{@dat[-1]}+1;
}
my $fp_info = 0;
# allocate stack frame
if ($cfa_rsp < -8) {
my $offset = -8 - $cfa_rsp;
if ($cfa_reg ne "%rsp" && $saved_regs{$cfa_reg} == -16) {
$fp_info = $WIN64_reg_idx{$cfa_reg};
push @dat, [0,$fp_info<<4]; # UWOP_PUSH_NONVOL
$len += $#{@dat[-1]}+1;
$offset -= 8;
}
if ($offset <= 128) {
my $alloc = ($offset - 8) >> 3;
push @dat, [0,$alloc<<4|2]; # UWOP_ALLOC_SMALL
} elsif ($offset < 0x80000) {
push @dat, [0,0x01,unpack("C2",pack("v",$offset>>3))];
} else {
push @dat, [0,0x11,unpack("C4",pack("V",$offset))];
}
$len += $#{@dat[-1]}+1;
}
# save frame pointer [if not pushed already]
if ($cfa_reg ne "%rsp" && $fp_info == 0) {
$fp_info = $WIN64_reg_idx{$cfa_reg};
if (defined(my $offset = $saved_regs{$cfa_reg})) {
$offset -= $cfa_rsp;
savereg($cfa_reg, $offset);
}
}
# set up frame pointer
if ($fp_info) {
push @dat, [0,($fp_info<<4)|3]; # UWOP_SET_FPREG
$len += $#{@dat[-1]}+1;
my $fp_off = $cfa_off - $cfa_rsp;
($fp_off > 240 or $fp_off&0xf) and die "invalid FP offset $fp_off";
$fp_info |= $fp_off&-16;
}
# save registers
foreach my $key (sort { $saved_regs{$b} <=> $saved_regs{$a} }
keys(%saved_regs)) {
next if ($cfa_reg ne "%rsp" && $cfa_reg eq $key);
my $offset = $saved_regs{$key} - $cfa_rsp;
savereg($key, $offset);
}
my @ret;
# generate 4-byte descriptor
push @ret, ".byte 1,0,".($len/2).",$fp_info";
$len += 4;
# keep objdump happy, pad to 4*n and add a 32-bit zero
unshift @dat, [(0)x(((-$len)&3)+4)];
$len += $#{@dat[0]}+1;
# pad to 8*n
unshift @dat, [(0)x((-$len)&7)] if ($len&7);
# emit data
while(defined(my $row = pop @dat)) {
push @ret, ".byte ". join(",",
map { sprintf "0x%02x",$_ } @{$row});
}
return @ret;
}
sub startproc {
return if ($cfa_rsp == -8);
($cfa_reg, $cfa_off, $cfa_rsp) = ("%rsp", -8, -8);
%saved_regs = ();
return "startproc";
}
sub endproc {
return if ($cfa_rsp == 0);
($cfa_reg, $cfa_off, $cfa_rsp) = ("%rsp", 0, 0);
%saved_regs = ();
return "endproc";
}
sub re {
my ($class, $line) = @_;
my $self = {};
my $ret;
if ($$line =~ s/^\s*\.cfi_(\w+)\s*//) {
bless $self,$class;
$ret = $self;
undef $self->{value};
my $dir = $1;
SWITCH: for ($dir) {
# What is $cfa_rsp? Effectively it's difference between %rsp
# value and current CFA, Canonical Frame Address, which is
# why it starts with -8. Recall that CFA is top of caller's
# stack...
/startproc/ && do { $dir = startproc(); last; };
/endproc/ && do { $dir = endproc();
# .cfi_remember_state directives that are not
# matched with .cfi_restore_state are
# unnecessary.
die "unpaired .cfi_remember_state" if (@cfa_stack);
last;
};
/def_cfa_register/
&& do { $cfa_off = $cfa_rsp if ($cfa_reg eq "%rsp");
$cfa_reg = $$line;
$cfa_rsp = $cfa_off if ($cfa_reg eq "%rsp");
last;
};
/def_cfa_offset/
&& do { $cfa_off = -1*eval($$line);
$cfa_rsp = $cfa_off if ($cfa_reg eq "%rsp");
last;
};
/adjust_cfa_offset/
&& do { my $val = 1*eval($$line);
$cfa_off -= $val;
if ($cfa_reg eq "%rsp") {
$cfa_rsp -= $val;
}
last;
};
/alloca/ && do { $dir = undef;
my $val = 1*eval($$line);
$cfa_rsp -= $val;
if ($cfa_reg eq "%rsp") {
$cfa_off -= $val;
$dir = "adjust_cfa_offset";
}
last;
};
/def_cfa/ && do { if ($$line =~ /(%r\w+)\s*(?:,\s*(.+))?/) {
$cfa_reg = $1;
if ($cfa_reg eq "%rsp" && !defined($2)) {
$cfa_off = $cfa_rsp;
$$line .= ",".(-$cfa_rsp);
} else {
$cfa_off = -1*eval($2);
$cfa_rsp = $cfa_off if ($cfa_reg eq "%rsp");
}
}
last;
};
/push/ && do { $dir = undef;
$cfa_rsp -= 8;
if ($cfa_reg eq "%rsp") {
$cfa_off = $cfa_rsp;
$self->{value} = ".cfi_adjust_cfa_offset\t8\n";
}
$saved_regs{$$line} = $cfa_rsp;
$self->{value} .= ".cfi_offset\t$$line,$cfa_rsp";
last;
};
/pop/ && do { $dir = undef;
$cfa_rsp += 8;
if ($cfa_reg eq "%rsp") {
$cfa_off = $cfa_rsp;
$self->{value} = ".cfi_adjust_cfa_offset\t-8\n";
}
$self->{value} .= ".cfi_restore\t$$line";
delete $saved_regs{$$line};
last;
};
/cfa_expression/
&& do { $dir = undef;
$self->{value} = ".cfi_escape\t" .
join(",", map(sprintf("0x%02x", $_),
cfa_expression($$line)));
last;
};
/remember_state/
&& do { push @cfa_stack,
[$cfa_reg,$cfa_off,$cfa_rsp,%saved_regs];
last;
};
/restore_state/
&& do { ($cfa_reg,$cfa_off,$cfa_rsp,%saved_regs)
= @{pop @cfa_stack};
last;
};
/offset/ && do { if ($$line =~ /(%\w+)(?:-%xmm(\d+))?\s*,\s*(.+)/) {
my ($reg, $off, $xmmlast) = ($1, 1*eval($3), $2);
if ($reg !~ /%xmm(\d+)/) {
$saved_regs{$reg} = $off;
} else {
$dir = undef;
$xmmlast //= $1;
for (my $i=$1; $i<=$xmmlast; $i++) {
$saved_regs{"%xmm$i"} = $off;
$off += 16;
}
}
}
last;
};
/restore/ && do { delete $saved_regs{$$line}; last; };
/end_prologue/
&& do { $dir = undef;
$self->{win64} = ".endprolog";
last;
};
/epilogue/ && do { $dir = undef;
$self->{win64} = ".epilogue";
$self->{value} = join("\n",
map { ".cfi_restore\t$_" }
sort keys(%saved_regs));
%saved_regs = ();
last;
};
}
$self->{value} = ".cfi_$dir\t$$line" if ($dir);
$$line = "";
}
return $ret;
}
sub out {
my $self = shift;
return $self->{value} if ($dwarf);
if ($win64 and $current_function->{unwind}
and my $ret = $self->{win64}) {
my ($reg, $off) = ($cfa_reg =~ /%(?!rsp)/) ? ($', $cfa_off)
: ("rsp", $cfa_rsp);
my $fname = $current_function->{name};
if ($ret eq ".endprolog") {
$ret = "";
if ($current_function->{abi} eq "svr4") {
$ret .= label::win64_args();
$saved_regs{"%rdi"} = 0; # relative to CFA, remember?
$saved_regs{"%rsi"} = 8;
}
push @pdata_seg,
".rva .LSEH_begin_${fname}",
".rva .LSEH_body_${fname}",
".rva .LSEH_info_${fname}_prologue","";
push @xdata_seg,
".LSEH_info_${fname}_prologue:";
if ($current_function->{unwind} eq "%rbp") {
if ($current_function->{abi} eq "svr4") {
push @xdata_seg,
".byte 1,4,6,0x05", # 6 unwind codes, %rbp is FP
".byte 4,0x74,2,0", # %rdi at 16(%rsp)
".byte 4,0x64,3,0", # %rsi at 24(%rsp)
".byte 4,0x53", # mov %rsp, %rbp
".byte 1,0x50", # push %rbp
".long 0,0" # pad to keep objdump happy
;
} else {
push @xdata_seg,
".byte 1,4,2,0x05", # 2 unwind codes, %rbp is FP
".byte 4,0x53", # mov %rsp, %rbp
".byte 1,0x50", # push %rbp
".long 0,0" # pad to keep objdump happy
;
}