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oot/tools/asm_processor/asm_processor.py
Jack Walker 087f561f77 First proper commit.
2020-03-17 00:31:30 -04:00

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#!/usr/bin/env python3
import argparse
import tempfile
import struct
import copy
import sys
import re
import os
from collections import namedtuple
MAX_FN_SIZE = 100
EI_NIDENT = 16
EI_CLASS = 4
EI_DATA = 5
EI_VERSION = 6
EI_OSABI = 7
EI_ABIVERSION = 8
STN_UNDEF = 0
SHN_UNDEF = 0
SHN_ABS = 0xfff1
SHN_COMMON = 0xfff2
SHN_XINDEX = 0xffff
SHN_LORESERVE = 0xff00
STT_NOTYPE = 0
STT_OBJECT = 1
STT_FUNC = 2
STT_SECTION = 3
STT_FILE = 4
STT_COMMON = 5
STT_TLS = 6
STB_LOCAL = 0
STB_GLOBAL = 1
STB_WEAK = 2
STV_DEFAULT = 0
STV_INTERNAL = 1
STV_HIDDEN = 2
STV_PROTECTED = 3
SHT_NULL = 0
SHT_PROGBITS = 1
SHT_SYMTAB = 2
SHT_STRTAB = 3
SHT_RELA = 4
SHT_HASH = 5
SHT_DYNAMIC = 6
SHT_NOTE = 7
SHT_NOBITS = 8
SHT_REL = 9
SHT_SHLIB = 10
SHT_DYNSYM = 11
SHT_INIT_ARRAY = 14
SHT_FINI_ARRAY = 15
SHT_PREINIT_ARRAY = 16
SHT_GROUP = 17
SHT_SYMTAB_SHNDX = 18
SHT_MIPS_GPTAB = 0x70000003
SHT_MIPS_DEBUG = 0x70000005
SHT_MIPS_REGINFO = 0x70000006
SHT_MIPS_OPTIONS = 0x7000000d
SHF_WRITE = 0x1
SHF_ALLOC = 0x2
SHF_EXECINSTR = 0x4
SHF_MERGE = 0x10
SHF_STRINGS = 0x20
SHF_INFO_LINK = 0x40
SHF_LINK_ORDER = 0x80
SHF_OS_NONCONFORMING = 0x100
SHF_GROUP = 0x200
SHF_TLS = 0x400
R_MIPS_32 = 2
R_MIPS_26 = 4
R_MIPS_HI16 = 5
R_MIPS_LO16 = 6
class ElfHeader:
"""
typedef struct {
unsigned char e_ident[EI_NIDENT];
Elf32_Half e_type;
Elf32_Half e_machine;
Elf32_Word e_version;
Elf32_Addr e_entry;
Elf32_Off e_phoff;
Elf32_Off e_shoff;
Elf32_Word e_flags;
Elf32_Half e_ehsize;
Elf32_Half e_phentsize;
Elf32_Half e_phnum;
Elf32_Half e_shentsize;
Elf32_Half e_shnum;
Elf32_Half e_shstrndx;
} Elf32_Ehdr;
"""
def __init__(self, data):
self.e_ident = data[:EI_NIDENT]
self.e_type, self.e_machine, self.e_version, self.e_entry, self.e_phoff, self.e_shoff, self.e_flags, self.e_ehsize, self.e_phentsize, self.e_phnum, self.e_shentsize, self.e_shnum, self.e_shstrndx = struct.unpack('>HHIIIIIHHHHHH', data[EI_NIDENT:])
assert self.e_ident[EI_CLASS] == 1 # 32-bit
assert self.e_ident[EI_DATA] == 2 # big-endian
assert self.e_type == 1 # relocatable
assert self.e_machine == 8 # MIPS I Architecture
assert self.e_phoff == 0 # no program header
assert self.e_shoff != 0 # section header
assert self.e_shstrndx != SHN_UNDEF
def to_bin(self):
return self.e_ident + struct.pack('>HHIIIIIHHHHHH', self.e_type,
self.e_machine, self.e_version, self.e_entry, self.e_phoff,
self.e_shoff, self.e_flags, self.e_ehsize, self.e_phentsize,
self.e_phnum, self.e_shentsize, self.e_shnum, self.e_shstrndx)
class Symbol:
"""
typedef struct {
Elf32_Word st_name;
Elf32_Addr st_value;
Elf32_Word st_size;
unsigned char st_info;
unsigned char st_other;
Elf32_Half st_shndx;
} Elf32_Sym;
"""
def __init__(self, data, strtab):
self.st_name, self.st_value, self.st_size, st_info, self.st_other, self.st_shndx = struct.unpack('>IIIBBH', data)
assert self.st_shndx != SHN_XINDEX, "too many sections (SHN_XINDEX not supported)"
self.bind = st_info >> 4
self.type = st_info & 15
self.name = strtab.lookup_str(self.st_name)
self.visibility = self.st_other & 3
def to_bin(self):
st_info = (self.bind << 4) | self.type
return struct.pack('>IIIBBH', self.st_name, self.st_value, self.st_size, st_info, self.st_other, self.st_shndx)
class Relocation:
def __init__(self, data, sh_type):
self.sh_type = sh_type
if sh_type == SHT_REL:
self.r_offset, self.r_info = struct.unpack('>II', data)
else:
self.r_offset, self.r_info, self.r_addend = struct.unpack('>III', data)
self.sym_index = self.r_info >> 8
self.rel_type = self.r_info & 0xff
def to_bin(self):
self.r_info = (self.sym_index << 8) | self.rel_type
if self.sh_type == SHT_REL:
return struct.pack('>II', self.r_offset, self.r_info)
else:
return struct.pack('>III', self.r_offset, self.r_info, self.r_addend)
class Section:
"""
typedef struct {
Elf32_Word sh_name;
Elf32_Word sh_type;
Elf32_Word sh_flags;
Elf32_Addr sh_addr;
Elf32_Off sh_offset;
Elf32_Word sh_size;
Elf32_Word sh_link;
Elf32_Word sh_info;
Elf32_Word sh_addralign;
Elf32_Word sh_entsize;
} Elf32_Shdr;
"""
def __init__(self, header, data, index):
self.sh_name, self.sh_type, self.sh_flags, self.sh_addr, self.sh_offset, self.sh_size, self.sh_link, self.sh_info, self.sh_addralign, self.sh_entsize = struct.unpack('>IIIIIIIIII', header)
assert not self.sh_flags & SHF_LINK_ORDER
if self.sh_entsize != 0:
assert self.sh_size % self.sh_entsize == 0
if self.sh_type == SHT_NOBITS:
self.data = ''
else:
self.data = data[self.sh_offset:self.sh_offset + self.sh_size]
self.index = index
self.relocated_by = []
@staticmethod
def from_parts(sh_name, sh_type, sh_flags, sh_link, sh_info, sh_addralign, sh_entsize, data, index):
header = struct.pack('>IIIIIIIIII', sh_name, sh_type, sh_flags, 0, 0, len(data), sh_link, sh_info, sh_addralign, sh_entsize)
return Section(header, data, index)
def lookup_str(self, index):
assert self.sh_type == SHT_STRTAB
to = self.data.find(b'\0', index)
assert to != -1
return self.data[index:to].decode('latin1')
def add_str(self, string):
assert self.sh_type == SHT_STRTAB
ret = len(self.data)
self.data += string.encode('latin1') + b'\0'
return ret
def is_rel(self):
return self.sh_type == SHT_REL or self.sh_type == SHT_RELA
def header_to_bin(self):
if self.sh_type != SHT_NOBITS:
self.sh_size = len(self.data)
return struct.pack('>IIIIIIIIII', self.sh_name, self.sh_type, self.sh_flags, self.sh_addr, self.sh_offset, self.sh_size, self.sh_link, self.sh_info, self.sh_addralign, self.sh_entsize)
def late_init(self, sections):
if self.sh_type == SHT_SYMTAB:
self.init_symbols(sections)
elif self.is_rel():
self.rel_target = sections[self.sh_info]
self.rel_target.relocated_by.append(self)
self.init_relocs()
def find_symbol(self, name):
assert self.sh_type == SHT_SYMTAB
for s in self.symbol_entries:
if s.name == name:
return (s.st_shndx, s.st_value)
return None
def find_symbol_in_section(self, name, section):
pos = self.find_symbol(name)
assert pos is not None
assert pos[0] == section.index
return pos[1]
def init_symbols(self, sections):
assert self.sh_type == SHT_SYMTAB
assert self.sh_entsize == 16
self.strtab = sections[self.sh_link]
entries = []
for i in range(0, self.sh_size, self.sh_entsize):
entries.append(Symbol(self.data[i:i+self.sh_entsize], self.strtab))
self.symbol_entries = entries
def init_relocs(self):
assert self.is_rel()
entries = []
for i in range(0, self.sh_size, self.sh_entsize):
entries.append(Relocation(self.data[i:i+self.sh_entsize], self.sh_type))
self.relocations = entries
def local_symbols(self):
assert self.sh_type == SHT_SYMTAB
return self.symbol_entries[:self.sh_info]
def global_symbols(self):
assert self.sh_type == SHT_SYMTAB
return self.symbol_entries[self.sh_info:]
class ElfFile:
def __init__(self, data):
self.data = data
assert data[:4] == b'\x7fELF', "not an ELF file"
self.elf_header = ElfHeader(data[0:52])
offset, size = self.elf_header.e_shoff, self.elf_header.e_shentsize
null_section = Section(data[offset:offset + size], data, 0)
num_sections = self.elf_header.e_shnum or null_section.sh_size
self.sections = [null_section]
for i in range(1, num_sections):
ind = offset + i * size
self.sections.append(Section(data[ind:ind + size], data, i))
symtab = None
for s in self.sections:
if s.sh_type == SHT_SYMTAB:
assert not symtab
symtab = s
assert symtab is not None
self.symtab = symtab
shstr = self.sections[self.elf_header.e_shstrndx]
for s in self.sections:
s.name = shstr.lookup_str(s.sh_name)
s.late_init(self.sections)
def find_section(self, name):
for s in self.sections:
if s.name == name:
return s
return None
def add_section(self, name, sh_type, sh_flags, sh_link, sh_info, sh_addralign, sh_entsize, data):
shstr = self.sections[self.elf_header.e_shstrndx]
sh_name = shstr.add_str(name)
s = Section.from_parts(sh_name=sh_name, sh_type=sh_type,
sh_flags=sh_flags, sh_link=sh_link, sh_info=sh_info,
sh_addralign=sh_addralign, sh_entsize=sh_entsize, data=data,
index=len(self.sections))
self.sections.append(s)
s.name = name
s.late_init(self.sections)
return s
def drop_irrelevant_sections(self):
# We can only drop sections at the end, since otherwise section
# references might be wrong. Luckily, these sections typically are.
while self.sections[-1].sh_type in [SHT_MIPS_DEBUG, SHT_MIPS_GPTAB]:
self.sections.pop()
def write(self, filename):
outfile = open(filename, 'wb')
outidx = 0
def write_out(data):
nonlocal outidx
outfile.write(data)
outidx += len(data)
def pad_out(align):
if align and outidx % align:
write_out(b'\0' * (align - outidx % align))
self.elf_header.e_shnum = len(self.sections)
write_out(self.elf_header.to_bin())
for s in self.sections:
if s.sh_type != SHT_NOBITS and s.sh_type != SHT_NULL:
pad_out(s.sh_addralign)
s.sh_offset = outidx
write_out(s.data)
pad_out(4)
self.elf_header.e_shoff = outidx
for s in self.sections:
write_out(s.header_to_bin())
outfile.seek(0)
outfile.write(self.elf_header.to_bin())
outfile.close()
def is_temp_name(name):
return name.startswith('_asmpp_')
class Failure(Exception):
def __init__(self, message):
self.message = message
def __str__(self):
return self.message
class GlobalState:
def __init__(self, min_instr_count, skip_instr_count):
# A value that hopefully never appears as a 32-bit rodata constant (or we
# miscompile late rodata). Increases by 1 in each step.
self.late_rodata_hex = 0xE0123456
self.namectr = 0
self.min_instr_count = min_instr_count
self.skip_instr_count = skip_instr_count
def next_late_rodata_hex(self):
dummy_bytes = struct.pack('>I', self.late_rodata_hex)
if (self.late_rodata_hex & 0xffff) == 0:
# Avoid lui
self.late_rodata_hex += 1
self.late_rodata_hex += 1
return dummy_bytes
def make_name(self, cat):
self.namectr += 1
return '_asmpp_{}{}'.format(cat, self.namectr)
Function = namedtuple('Function', ['text_glabels', 'asm_conts', 'late_rodata_dummy_bytes', 'late_rodata_asm_conts', 'fn_desc', 'data'])
class GlobalAsmBlock:
def __init__(self, fn_desc):
self.fn_desc = fn_desc
self.cur_section = '.text'
self.asm_conts = []
self.late_rodata_asm_conts = []
self.late_rodata_alignment = 0
self.late_rodata_alignment_from_content = False
self.text_glabels = []
self.fn_section_sizes = {
'.text': 0,
'.data': 0,
'.bss': 0,
'.rodata': 0,
'.late_rodata': 0,
}
self.fn_ins_inds = []
self.glued_line = ''
self.num_lines = 0
def fail(self, message, line=None):
context = self.fn_desc
if line:
context += ", at line \"" + line + "\""
raise Failure(message + "\nwithin " + context)
def count_quoted_size(self, line, z, real_line, output_enc):
line = line.encode(output_enc).decode('latin1')
in_quote = False
num_parts = 0
ret = 0
i = 0
digits = "0123456789" # 0-7 would be more sane, but this matches GNU as
while i < len(line):
c = line[i]
i += 1
if not in_quote:
if c == '"':
in_quote = True
num_parts += 1
else:
if c == '"':
in_quote = False
continue
ret += 1
if c != '\\':
continue
if i == len(line):
self.fail("backslash at end of line not supported", real_line)
c = line[i]
i += 1
# (if c is in "bfnrtv", we have a real escaped literal)
if c == 'x':
# hex literal, consume any number of hex chars, possibly none
while i < len(line) and line[i] in digits + "abcdefABCDEF":
i += 1
elif c in digits:
# octal literal, consume up to two more digits
it = 0
while i < len(line) and line[i] in digits and it < 2:
i += 1
it += 1
if in_quote:
self.fail("unterminated string literal", real_line)
if num_parts == 0:
self.fail(".ascii with no string", real_line)
return ret + num_parts if z else ret
def align4(self):
while self.fn_section_sizes[self.cur_section] % 4 != 0:
self.fn_section_sizes[self.cur_section] += 1
def add_sized(self, size, line):
if self.cur_section in ['.text', '.late_rodata']:
if size % 4 != 0:
self.fail("size must be a multiple of 4", line)
if size < 0:
self.fail("size cannot be negative", line)
self.fn_section_sizes[self.cur_section] += size
if self.cur_section == '.text':
if not self.text_glabels:
self.fail(".text block without an initial glabel", line)
self.fn_ins_inds.append((self.num_lines - 1, size // 4))
def process_line(self, line, output_enc):
self.num_lines += 1
if line.endswith('\\'):
self.glued_line += line[:-1]
return
line = self.glued_line + line
self.glued_line = ''
real_line = line
line = re.sub(r'/\*.*?\*/', '', line)
line = re.sub(r'#.*', '', line)
line = line.strip()
line = re.sub(r'^[a-zA-Z0-9_]+:\s*', '', line)
changed_section = False
emitting_double = False
if line.startswith('glabel ') and self.cur_section == '.text':
self.text_glabels.append(line.split()[1])
if not line:
pass # empty line
elif line.startswith('glabel ') or (' ' not in line and line.endswith(':')):
pass # label
elif line.startswith('.section') or line in ['.text', '.data', '.rdata', '.rodata', '.bss', '.late_rodata']:
# section change
self.cur_section = '.rodata' if line == '.rdata' else line.split(',')[0].split()[-1]
if self.cur_section not in ['.data', '.text', '.rodata', '.late_rodata', '.bss']:
self.fail("unrecognized .section directive", real_line)
changed_section = True
elif line.startswith('.late_rodata_alignment'):
if self.cur_section != '.late_rodata':
self.fail(".late_rodata_alignment must occur within .late_rodata section", real_line)
value = int(line.split()[1])
if value not in [4, 8]:
self.fail(".late_rodata_alignment argument must be 4 or 8", real_line)
if self.late_rodata_alignment and self.late_rodata_alignment != value:
self.fail(".late_rodata_alignment alignment assumption conflicts with earlier .double directive. Make sure to provide explicit alignment padding.")
self.late_rodata_alignment = value
changed_section = True
elif line.startswith('.incbin'):
self.add_sized(int(line.split(',')[-1].strip(), 0), real_line)
elif line.startswith('.word') or line.startswith('.float'):
self.align4()
self.add_sized(4 * len(line.split(',')), real_line)
elif line.startswith('.double'):
self.align4()
if self.cur_section == '.late_rodata':
align8 = self.fn_section_sizes[self.cur_section] % 8
# Automatically set late_rodata_alignment, so the generated C code uses doubles.
# This gives us correct alignment for the transferred doubles even when the
# late_rodata_alignment is wrong, e.g. for non-matching compilation.
if not self.late_rodata_alignment:
self.late_rodata_alignment = 8 - align8
self.late_rodata_alignment_from_content = True
elif self.late_rodata_alignment != 8 - align8:
if self.late_rodata_alignment_from_content:
self.fail("found two .double directives with different start addresses mod 8. Make sure to provide explicit alignment padding.", real_line)
else:
self.fail(".double at address that is not 0 mod 8 (based on .late_rodata_alignment assumption). Make sure to provide explicit alignment padding.", real_line)
self.add_sized(8 * len(line.split(',')), real_line)
emitting_double = True
elif line.startswith('.space'):
self.add_sized(int(line.split()[1], 0), real_line)
elif line.startswith('.balign') or line.startswith('.align'):
align = int(line.split()[1])
if align != 4:
self.fail("only .balign 4 is supported", real_line)
self.align4()
elif line.startswith('.asci'):
z = (line.startswith('.asciz') or line.startswith('.asciiz'))
self.add_sized(self.count_quoted_size(line, z, real_line, output_enc), real_line)
elif line.startswith('.'):
# .macro, ...
self.fail("asm directive not supported", real_line)
else:
# Unfortunately, macros are hard to support for .rodata --
# we don't know how how space they will expand to before
# running the assembler, but we need that information to
# construct the C code. So if we need that we'll either
# need to run the assembler twice (at least in some rare
# cases), or change how this program is invoked.
# Similarly, we can't currently deal with pseudo-instructions
# that expand to several real instructions.
if self.cur_section != '.text':
self.fail("instruction or macro call in non-.text section? not supported", real_line)
self.add_sized(4, real_line)
if self.cur_section == '.late_rodata':
if not changed_section:
if emitting_double:
self.late_rodata_asm_conts.append(".align 0")
self.late_rodata_asm_conts.append(real_line)
if emitting_double:
self.late_rodata_asm_conts.append(".align 2")
else:
self.asm_conts.append(real_line)
def finish(self, state):
src = [''] * (self.num_lines + 1)
late_rodata_dummy_bytes = []
late_rodata_fn_output = []
if self.fn_section_sizes['.late_rodata'] > 0:
# Generate late rodata by emitting unique float constants.
# This requires 3 instructions for each 4 bytes of rodata.
# If we know alignment, we can use doubles, which give 3
# instructions for 8 bytes of rodata.
size = self.fn_section_sizes['.late_rodata'] // 4
skip_next = False
for i in range(size):
if skip_next:
skip_next = False
continue
dummy_bytes = state.next_late_rodata_hex()
late_rodata_dummy_bytes.append(dummy_bytes)
if self.late_rodata_alignment == 4 * ((i + 1) % 2 + 1) and i + 1 < size:
dummy_bytes2 = state.next_late_rodata_hex()
late_rodata_dummy_bytes.append(dummy_bytes2)
fval, = struct.unpack('>d', dummy_bytes + dummy_bytes2)
late_rodata_fn_output.append('*(volatile double*)0 = {};'.format(fval))
skip_next = True
else:
fval, = struct.unpack('>f', dummy_bytes)
late_rodata_fn_output.append('*(volatile float*)0 = {}f;'.format(fval))
late_rodata_fn_output.append('')
late_rodata_fn_output.append('')
text_name = None
if self.fn_section_sizes['.text'] > 0 or late_rodata_fn_output:
text_name = state.make_name('func')
src[0] = 'void {}(void) {{'.format(text_name)
src[self.num_lines] = '}'
instr_count = self.fn_section_sizes['.text'] // 4
if instr_count < state.min_instr_count:
self.fail("too short .text block")
tot_emitted = 0
tot_skipped = 0
fn_emitted = 0
fn_skipped = 0
rodata_stack = late_rodata_fn_output[::-1]
for (line, count) in self.fn_ins_inds:
for _ in range(count):
if (fn_emitted > MAX_FN_SIZE and instr_count - tot_emitted > state.min_instr_count and
(not rodata_stack or rodata_stack[-1])):
# Don't let functions become too large. When a function reaches 284
# instructions, and -O2 -framepointer flags are passed, the IRIX
# compiler decides it is a great idea to start optimizing more.
fn_emitted = 0
fn_skipped = 0
src[line] += ' }} void {}(void) {{ '.format(state.make_name('large_func'))
if fn_skipped < state.skip_instr_count:
fn_skipped += 1
tot_skipped += 1
elif rodata_stack:
src[line] += rodata_stack.pop()
else:
src[line] += '*(volatile int*)0 = 0;'
tot_emitted += 1
fn_emitted += 1
if rodata_stack:
size = len(late_rodata_fn_output) // 3
available = instr_count - tot_skipped
self.fail(
"late rodata to text ratio is too high: {} / {} must be <= 1/3\n"
"add .late_rodata_alignment (4|8) to the .late_rodata "
"block to double the allowed ratio."
.format(size, available))
rodata_name = None
if self.fn_section_sizes['.rodata'] > 0:
rodata_name = state.make_name('rodata')
src[self.num_lines] += ' const char {}[{}] = {{1}};'.format(rodata_name, self.fn_section_sizes['.rodata'])
data_name = None
if self.fn_section_sizes['.data'] > 0:
data_name = state.make_name('data')
src[self.num_lines] += ' char {}[{}] = {{1}};'.format(data_name, self.fn_section_sizes['.data'])
bss_name = None
if self.fn_section_sizes['.bss'] > 0:
bss_name = state.make_name('bss')
src[self.num_lines] += ' char {}[{}];'.format(bss_name, self.fn_section_sizes['.bss'])
fn = Function(
text_glabels=self.text_glabels,
asm_conts=self.asm_conts,
late_rodata_dummy_bytes=late_rodata_dummy_bytes,
late_rodata_asm_conts=self.late_rodata_asm_conts,
fn_desc=self.fn_desc,
data={
'.text': (text_name, self.fn_section_sizes['.text']),
'.data': (data_name, self.fn_section_sizes['.data']),
'.rodata': (rodata_name, self.fn_section_sizes['.rodata']),
'.bss': (bss_name, self.fn_section_sizes['.bss']),
})
return src, fn
def parse_source(f, opt, framepointer, input_enc, output_enc, print_source=None):
if opt in ['O2', 'O1']:
if framepointer:
min_instr_count = 6
skip_instr_count = 5
else:
min_instr_count = 2
skip_instr_count = 1
elif opt == 'g':
if framepointer:
min_instr_count = 7
skip_instr_count = 7
else:
min_instr_count = 4
skip_instr_count = 4
else:
if opt != 'g3':
raise Failure("must pass one of -g, -O1, -O2, -O2 -g3")
if framepointer:
min_instr_count = 4
skip_instr_count = 4
else:
min_instr_count = 2
skip_instr_count = 2
state = GlobalState(min_instr_count, skip_instr_count)
global_asm = None
asm_functions = []
output_lines = []
for line_no, raw_line in enumerate(f, 1):
raw_line = raw_line.rstrip()
line = raw_line.lstrip()
# Print exactly one output line per source line, to make compiler
# errors have correct line numbers. These will be overridden with
# reasonable content further down.
output_lines.append('')
if global_asm is not None:
if line.startswith(')'):
src, fn = global_asm.finish(state)
for i, line2 in enumerate(src):
output_lines[start_index + i] = line2
asm_functions.append(fn)
global_asm = None
else:
global_asm.process_line(raw_line, output_enc)
else:
if line in ['GLOBAL_ASM(', '#pragma GLOBAL_ASM(']:
global_asm = GlobalAsmBlock("GLOBAL_ASM block at line " + str(line_no))
start_index = len(output_lines)
elif ((line.startswith('GLOBAL_ASM("') or line.startswith('#pragma GLOBAL_ASM("'))
and line.endswith('")')):
fname = line[line.index('(') + 2 : -2]
global_asm = GlobalAsmBlock(fname)
with open(fname, encoding=input_enc) as f:
for line2 in f:
global_asm.process_line(line2.rstrip(), output_enc)
src, fn = global_asm.finish(state)
output_lines[-1] = ''.join(src)
asm_functions.append(fn)
global_asm = None
else:
output_lines[-1] = raw_line
if print_source:
for line in output_lines:
print_source.write(line.encode(output_enc) + b'\n')
print_source.flush()
if print_source != sys.stdout.buffer:
print_source.close()
return asm_functions
def fixup_objfile(objfile_name, functions, asm_prelude, assembler, output_enc):
SECTIONS = ['.data', '.text', '.rodata', '.bss']
with open(objfile_name, 'rb') as f:
objfile = ElfFile(f.read())
prev_locs = {
'.text': 0,
'.data': 0,
'.rodata': 0,
'.bss': 0,
}
to_copy = {
'.text': [],
'.data': [],
'.rodata': [],
'.bss': [],
}
asm = []
late_rodata_dummy_bytes = []
late_rodata_asm = []
late_rodata_source_name_start = None
late_rodata_source_name_end = None
# Generate an assembly file with all the assembly we need to fill in. For
# simplicity we pad with nops/.space so that addresses match exactly, so we
# don't have to fix up relocations/symbol references.
all_text_glabels = set()
for function in functions:
ifdefed = False
for sectype, (temp_name, size) in function.data.items():
if temp_name is None:
continue
assert size > 0
loc = objfile.symtab.find_symbol(temp_name)
if loc is None:
ifdefed = True
break
loc = loc[1]
prev_loc = prev_locs[sectype]
assert loc >= prev_loc, sectype
if loc != prev_loc:
asm.append('.section ' + sectype)
if sectype == '.text':
for i in range((loc - prev_loc) // 4):
asm.append('nop')
else:
asm.append('.space {}'.format(loc - prev_loc))
to_copy[sectype].append((loc, size, temp_name, function.fn_desc))
prev_locs[sectype] = loc + size
if not ifdefed:
all_text_glabels.update(function.text_glabels)
late_rodata_dummy_bytes.append(function.late_rodata_dummy_bytes)
late_rodata_asm.append(function.late_rodata_asm_conts)
for sectype, (temp_name, size) in function.data.items():
if temp_name is not None:
asm.append('.section ' + sectype)
asm.append('glabel ' + temp_name + '_asm_start')
asm.append('.text')
for line in function.asm_conts:
asm.append(line)
for sectype, (temp_name, size) in function.data.items():
if temp_name is not None:
asm.append('.section ' + sectype)
asm.append('glabel ' + temp_name + '_asm_end')
if any(late_rodata_asm):
late_rodata_source_name_start = '_asmpp_late_rodata_start'
late_rodata_source_name_end = '_asmpp_late_rodata_end'
asm.append('.rdata')
asm.append('glabel {}'.format(late_rodata_source_name_start))
for conts in late_rodata_asm:
asm.extend(conts)
asm.append('glabel {}'.format(late_rodata_source_name_end))
o_file = tempfile.NamedTemporaryFile(prefix='asm-processor', suffix='.o', delete=False)
o_name = o_file.name
o_file.close()
s_file = tempfile.NamedTemporaryFile(prefix='asm-processor', suffix='.s', delete=False)
s_name = s_file.name
try:
s_file.write(asm_prelude + b'\n')
for line in asm:
s_file.write(line.encode(output_enc) + b'\n')
s_file.close()
ret = os.system(assembler + " " + s_name + " -o " + o_name)
if ret != 0:
raise Failure("failed to assemble")
with open(o_name, 'rb') as f:
asm_objfile = ElfFile(f.read())
# Remove some clutter from objdump output
objfile.drop_irrelevant_sections()
# Unify reginfo sections
target_reginfo = objfile.find_section('.reginfo')
source_reginfo_data = list(asm_objfile.find_section('.reginfo').data)
data = list(target_reginfo.data)
for i in range(20):
data[i] |= source_reginfo_data[i]
target_reginfo.data = bytes(data)
# Move over section contents
modified_text_positions = set()
last_rodata_pos = 0
for sectype in SECTIONS:
if not to_copy[sectype]:
continue
source = asm_objfile.find_section(sectype)
assert source is not None, "didn't find source section: " + sectype
for (pos, count, temp_name, fn_desc) in to_copy[sectype]:
loc1 = asm_objfile.symtab.find_symbol_in_section(temp_name + '_asm_start', source)
loc2 = asm_objfile.symtab.find_symbol_in_section(temp_name + '_asm_end', source)
assert loc1 == pos, "assembly and C files don't line up for section " + sectype + ", " + fn_desc
if loc2 - loc1 != count:
raise Failure("incorrectly computed size for section " + sectype + ", " + fn_desc + ". If using .double, make sure to provide explicit alignment padding.")
if sectype == '.bss':
continue
target = objfile.find_section(sectype)
assert target is not None, "missing target section of type " + sectype
data = list(target.data)
for (pos, count, _, _) in to_copy[sectype]:
data[pos:pos + count] = source.data[pos:pos + count]
if sectype == '.text':
assert count % 4 == 0
assert pos % 4 == 0
for i in range(count // 4):
modified_text_positions.add(pos + 4 * i)
elif sectype == '.rodata':
last_rodata_pos = pos + count
target.data = bytes(data)
# Move over late rodata. This is heuristic, sadly, since I can't think
# of another way of doing it.
moved_late_rodata = {}
if any(late_rodata_dummy_bytes):
source = asm_objfile.find_section('.rodata')
target = objfile.find_section('.rodata')
source_pos = asm_objfile.symtab.find_symbol_in_section(late_rodata_source_name_start, source)
source_end = asm_objfile.symtab.find_symbol_in_section(late_rodata_source_name_end, source)
if source_end - source_pos != sum(map(len, late_rodata_dummy_bytes)) * 4:
raise Failure("computed wrong size of .late_rodata")
new_data = list(target.data)
for dummy_bytes_list in late_rodata_dummy_bytes:
for index, dummy_bytes in enumerate(dummy_bytes_list):
pos = target.data.index(dummy_bytes, last_rodata_pos)
if target.data.find(dummy_bytes, pos + 4) != -1:
raise Failure("multiple occurrences of late_rodata hex magic. Change asm-processor to use something better than 0xE0123456!")
if index == 0 and len(dummy_bytes_list) > 1 and target.data[pos+4:pos+8] == b'\0\0\0\0':
# Ugly hack to handle double alignment for non-matching builds.
# We were told by .late_rodata_alignment (or deduced from a .double)
# that a function's late_rodata started out 4 (mod 8), and emitted
# a float and then a double. But it was actually 0 (mod 8), so our
# double was moved by 4 bytes. To make them adjacent to keep jump
# tables correct, move the float by 4 bytes as well.
new_data[pos:pos+4] = b'\0\0\0\0'
pos += 4
new_data[pos:pos+4] = source.data[source_pos:source_pos+4]
moved_late_rodata[source_pos] = pos
last_rodata_pos = pos + 4
source_pos += 4
target.data = bytes(new_data)
# Merge strtab data.
strtab_adj = len(objfile.symtab.strtab.data)
objfile.symtab.strtab.data += asm_objfile.symtab.strtab.data
# Find relocated symbols
relocated_symbols = set()
for sectype in SECTIONS:
for obj in [asm_objfile, objfile]:
sec = obj.find_section(sectype)
if sec is None:
continue
for reltab in sec.relocated_by:
for rel in reltab.relocations:
relocated_symbols.add(obj.symtab.symbol_entries[rel.sym_index])
# Move over symbols, deleting the temporary function labels.
# Sometimes this naive procedure results in duplicate symbols, or UNDEF
# symbols that are also defined the same .o file. Hopefully that's fine.
# Skip over local symbols that aren't used relocated against, to avoid
# conflicts.
new_local_syms = [s for s in objfile.symtab.local_symbols() if not is_temp_name(s.name)]
new_global_syms = [s for s in objfile.symtab.global_symbols() if not is_temp_name(s.name)]
for i, s in enumerate(asm_objfile.symtab.symbol_entries):
is_local = (i < asm_objfile.symtab.sh_info)
if is_local and s not in relocated_symbols:
continue
if is_temp_name(s.name):
continue
if s.st_shndx not in [SHN_UNDEF, SHN_ABS]:
section_name = asm_objfile.sections[s.st_shndx].name
if section_name not in SECTIONS:
raise Failure("generated assembly .o must only have symbols for .text, .data, .rodata, ABS and UNDEF, but found " + section_name)
s.st_shndx = objfile.find_section(section_name).index
# glabel's aren't marked as functions, making objdump output confusing. Fix that.
if s.name in all_text_glabels:
s.type = STT_FUNC
if objfile.sections[s.st_shndx].name == '.rodata' and s.st_value in moved_late_rodata:
s.st_value = moved_late_rodata[s.st_value]
s.st_name += strtab_adj
if is_local:
new_local_syms.append(s)
else:
new_global_syms.append(s)
new_syms = new_local_syms + new_global_syms
for i, s in enumerate(new_syms):
s.new_index = i
objfile.symtab.data = b''.join(s.to_bin() for s in new_syms)
objfile.symtab.sh_info = len(new_local_syms)
# Move over relocations
for sectype in SECTIONS:
source = asm_objfile.find_section(sectype)
target = objfile.find_section(sectype)
if target is not None:
# fixup relocation symbol indices, since we butchered them above
for reltab in target.relocated_by:
nrels = []
for rel in reltab.relocations:
if sectype == '.text' and rel.r_offset in modified_text_positions:
# don't include relocations for late_rodata dummy code
continue
# hopefully we don't have relocations for local or
# temporary symbols, so new_index exists
rel.sym_index = objfile.symtab.symbol_entries[rel.sym_index].new_index
nrels.append(rel)
reltab.relocations = nrels
reltab.data = b''.join(rel.to_bin() for rel in nrels)
if not source:
continue
target_reltab = objfile.find_section('.rel' + sectype)
target_reltaba = objfile.find_section('.rela' + sectype)
for reltab in source.relocated_by:
for rel in reltab.relocations:
rel.sym_index = asm_objfile.symtab.symbol_entries[rel.sym_index].new_index
if sectype == '.rodata' and rel.r_offset in moved_late_rodata:
rel.r_offset = moved_late_rodata[rel.r_offset]
new_data = b''.join(rel.to_bin() for rel in reltab.relocations)
if reltab.sh_type == SHT_REL:
if not target_reltab:
target_reltab = objfile.add_section('.rel' + sectype,
sh_type=SHT_REL, sh_flags=0,
sh_link=objfile.symtab.index, sh_info=target.index,
sh_addralign=4, sh_entsize=8, data=b'')
target_reltab.data += new_data
else:
if not target_reltaba:
target_reltaba = objfile.add_section('.rela' + sectype,
sh_type=SHT_RELA, sh_flags=0,
sh_link=objfile.symtab.index, sh_info=target.index,
sh_addralign=4, sh_entsize=12, data=b'')
target_reltaba.data += new_data
objfile.write(objfile_name)
finally:
s_file.close()
os.remove(s_name)
try:
os.remove(o_name)
except:
pass
def run_wrapped(argv, outfile):
parser = argparse.ArgumentParser(description="Pre-process .c files and post-process .o files to enable embedding assembly into C.")
parser.add_argument('filename', help="path to .c code")
parser.add_argument('--post-process', dest='objfile', help="path to .o file to post-process")
parser.add_argument('--assembler', dest='assembler', help="assembler command (e.g. \"mips-linux-gnu-as -march=vr4300 -mabi=32\")")
parser.add_argument('--asm-prelude', dest='asm_prelude', help="path to a file containing a prelude to the assembly file (with .set and .macro directives, e.g.)")
parser.add_argument('--input-enc', default='latin1', help="Input encoding (default: latin1)")
parser.add_argument('--output-enc', default='latin1', help="Output encoding (default: latin1)")
parser.add_argument('-framepointer', dest='framepointer', action='store_true')
parser.add_argument('-g3', dest='g3', action='store_true')
group = parser.add_mutually_exclusive_group(required=True)
group.add_argument('-O1', dest='opt', action='store_const', const='O1')
group.add_argument('-O2', dest='opt', action='store_const', const='O2')
group.add_argument('-g', dest='opt', action='store_const', const='g')
args = parser.parse_args(argv)
opt = args.opt
if args.g3:
if opt != 'O2':
raise Failure("-g3 is only supported together with -O2")
opt = 'g3'
if args.objfile is None:
with open(args.filename, encoding=args.input_enc) as f:
parse_source(f, opt=opt, framepointer=args.framepointer, input_enc=args.input_enc, output_enc=args.output_enc, print_source=outfile)
else:
if args.assembler is None:
raise Failure("must pass assembler command")
with open(args.filename, encoding=args.input_enc) as f:
functions = parse_source(f, opt=opt, framepointer=args.framepointer, input_enc=args.input_enc, output_enc=args.output_enc)
if not functions:
return
asm_prelude = b''
if args.asm_prelude:
with open(args.asm_prelude, 'rb') as f:
asm_prelude = f.read()
fixup_objfile(args.objfile, functions, asm_prelude, args.assembler, args.output_enc)
def run(argv, outfile=sys.stdout.buffer):
try:
run_wrapped(argv, outfile)
except Failure as e:
print("Error:", e, file=sys.stderr)
sys.exit(1)
if __name__ == "__main__":
run(sys.argv[1:])
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