| #!/usr/bin/env python |
| # Script to analyze code and arrange ld sections. |
| # |
| # Copyright (C) 2008-2010 Kevin O'Connor <kevin@koconnor.net> |
| # |
| # This file may be distributed under the terms of the GNU GPLv3 license. |
| |
| import sys |
| |
| # LD script headers/trailers |
| COMMONHEADER = """ |
| /* DO NOT EDIT! This is an autogenerated file. See tools/layoutrom.py. */ |
| OUTPUT_FORMAT("elf32-i386") |
| OUTPUT_ARCH("i386") |
| SECTIONS |
| { |
| """ |
| COMMONTRAILER = """ |
| |
| /* Discard regular data sections to force a link error if |
| * code attempts to access data not marked with VAR16 (or other |
| * appropriate macro) |
| */ |
| /DISCARD/ : { |
| *(.text*) *(.data*) *(.bss*) *(.rodata*) |
| *(COMMON) *(.discard*) *(.eh_frame) |
| } |
| } |
| """ |
| |
| |
| ###################################################################### |
| # Determine section locations |
| ###################################################################### |
| |
| # Align 'pos' to 'alignbytes' offset |
| def alignpos(pos, alignbytes): |
| mask = alignbytes - 1 |
| return (pos + mask) & ~mask |
| |
| # Determine the final addresses for a list of sections that end at an |
| # address. |
| def setSectionsStart(sections, endaddr, minalign=1): |
| totspace = 0 |
| for section in sections: |
| if section.align > minalign: |
| minalign = section.align |
| totspace = alignpos(totspace, section.align) + section.size |
| startaddr = (endaddr - totspace) / minalign * minalign |
| curaddr = startaddr |
| # out = [(addr, sectioninfo), ...] |
| out = [] |
| for section in sections: |
| curaddr = alignpos(curaddr, section.align) |
| section.finalloc = curaddr |
| curaddr += section.size |
| return startaddr |
| |
| # The 16bit code can't exceed 64K of space. |
| BUILD_BIOS_ADDR = 0xf0000 |
| BUILD_BIOS_SIZE = 0x10000 |
| |
| # Layout the 16bit code. This ensures sections with fixed offset |
| # requirements are placed in the correct location. It also places the |
| # 16bit code as high as possible in the f-segment. |
| def fitSections(sections, fillsections): |
| # fixedsections = [(addr, section), ...] |
| fixedsections = [] |
| for section in sections: |
| if section.name.startswith('.fixedaddr.'): |
| addr = int(section.name[11:], 16) |
| section.finalloc = addr |
| fixedsections.append((addr, section)) |
| if section.align != 1: |
| print "Error: Fixed section %s has non-zero alignment (%d)" % ( |
| section.name, section.align) |
| sys.exit(1) |
| fixedsections.sort() |
| firstfixed = fixedsections[0][0] |
| |
| # Find freespace in fixed address area |
| # fixedAddr = [(freespace, section), ...] |
| fixedAddr = [] |
| for i in range(len(fixedsections)): |
| fixedsectioninfo = fixedsections[i] |
| addr, section = fixedsectioninfo |
| if i == len(fixedsections) - 1: |
| nextaddr = BUILD_BIOS_SIZE |
| else: |
| nextaddr = fixedsections[i+1][0] |
| avail = nextaddr - addr - section.size |
| fixedAddr.append((avail, section)) |
| fixedAddr.sort() |
| |
| # Attempt to fit other sections into fixed area |
| canrelocate = [(section.size, section.align, section.name, section) |
| for section in fillsections] |
| canrelocate.sort() |
| canrelocate = [section for size, align, name, section in canrelocate] |
| totalused = 0 |
| for freespace, fixedsection in fixedAddr: |
| addpos = fixedsection.finalloc + fixedsection.size |
| totalused += fixedsection.size |
| nextfixedaddr = addpos + freespace |
| # print "Filling section %x uses %d, next=%x, available=%d" % ( |
| # fixedsection.finalloc, fixedsection.size, nextfixedaddr, freespace) |
| while 1: |
| canfit = None |
| for fitsection in canrelocate: |
| if addpos + fitsection.size > nextfixedaddr: |
| # Can't fit and nothing else will fit. |
| break |
| fitnextaddr = alignpos(addpos, fitsection.align) + fitsection.size |
| # print "Test %s - %x vs %x" % ( |
| # fitsection.name, fitnextaddr, nextfixedaddr) |
| if fitnextaddr > nextfixedaddr: |
| # This item can't fit. |
| continue |
| canfit = (fitnextaddr, fitsection) |
| if canfit is None: |
| break |
| # Found a section that can fit. |
| fitnextaddr, fitsection = canfit |
| canrelocate.remove(fitsection) |
| fitsection.finalloc = addpos |
| addpos = fitnextaddr |
| totalused += fitsection.size |
| # print " Adding %s (size %d align %d) pos=%x avail=%d" % ( |
| # fitsection[2], fitsection[0], fitsection[1] |
| # , fitnextaddr, nextfixedaddr - fitnextaddr) |
| |
| # Report stats |
| total = BUILD_BIOS_SIZE-firstfixed |
| slack = total - totalused |
| print ("Fixed space: 0x%x-0x%x total: %d slack: %d" |
| " Percent slack: %.1f%%" % ( |
| firstfixed, BUILD_BIOS_SIZE, total, slack, |
| (float(slack) / total) * 100.0)) |
| |
| return firstfixed |
| |
| # Return the subset of sections with a given name prefix |
| def getSectionsPrefix(sections, category, prefix): |
| return [section for section in sections |
| if section.category == category and section.name.startswith(prefix)] |
| |
| def doLayout(sections): |
| # Determine 16bit positions |
| textsections = getSectionsPrefix(sections, '16', '.text.') |
| rodatasections = (getSectionsPrefix(sections, '16', '.rodata.str1.1') |
| + getSectionsPrefix(sections, '16', '.rodata.__func__.')) |
| datasections = getSectionsPrefix(sections, '16', '.data16.') |
| fixedsections = getSectionsPrefix(sections, '16', '.fixedaddr.') |
| |
| firstfixed = fitSections(fixedsections, textsections) |
| remsections = [s for s in textsections+rodatasections+datasections |
| if s.finalloc is None] |
| code16_start = setSectionsStart(remsections, firstfixed) |
| |
| # Determine 32seg positions |
| textsections = getSectionsPrefix(sections, '32seg', '.text.') |
| rodatasections = (getSectionsPrefix(sections, '32seg', '.rodata.str1.1') |
| +getSectionsPrefix(sections, '32seg', '.rodata.__func__.')) |
| datasections = getSectionsPrefix(sections, '32seg', '.data32seg.') |
| |
| code32seg_start = setSectionsStart( |
| textsections + rodatasections + datasections, code16_start) |
| |
| # Determine 32flat runtime positions |
| textsections = getSectionsPrefix(sections, '32flat', '.text.') |
| rodatasections = getSectionsPrefix(sections, '32flat', '.rodata') |
| datasections = getSectionsPrefix(sections, '32flat', '.data.') |
| bsssections = getSectionsPrefix(sections, '32flat', '.bss.') |
| |
| code32flat_start = setSectionsStart( |
| textsections + rodatasections + datasections + bsssections |
| , code32seg_start + BUILD_BIOS_ADDR, 16) |
| |
| # Determine 32flat init positions |
| textsections = getSectionsPrefix(sections, '32init', '.text.') |
| rodatasections = getSectionsPrefix(sections, '32init', '.rodata') |
| datasections = getSectionsPrefix(sections, '32init', '.data.') |
| bsssections = getSectionsPrefix(sections, '32init', '.bss.') |
| |
| code32init_start = setSectionsStart( |
| textsections + rodatasections + datasections + bsssections |
| , code32flat_start, 16) |
| |
| # Print statistics |
| size16 = BUILD_BIOS_SIZE - code16_start |
| size32seg = code16_start - code32seg_start |
| size32flat = code32seg_start + BUILD_BIOS_ADDR - code32flat_start |
| size32init = code32flat_start - code32init_start |
| print "16bit size: %d" % size16 |
| print "32bit segmented size: %d" % size32seg |
| print "32bit flat size: %d" % size32flat |
| print "32bit flat init size: %d" % size32init |
| |
| |
| ###################################################################### |
| # Linker script output |
| ###################################################################### |
| |
| # Write LD script includes for the given cross references |
| def outXRefs(sections): |
| xrefs = {} |
| out = "" |
| for section in sections: |
| for reloc in section.relocs: |
| symbol = reloc.symbol |
| if (symbol.section is None |
| or (symbol.section.fileid == section.fileid |
| and symbol.name == reloc.symbolname) |
| or reloc.symbolname in xrefs): |
| continue |
| xrefs[reloc.symbolname] = 1 |
| addr = symbol.section.finalloc + symbol.offset |
| if (section.fileid == '32flat' |
| and symbol.section.fileid in ('16', '32seg')): |
| addr += BUILD_BIOS_ADDR |
| out += "%s = 0x%x ;\n" % (reloc.symbolname, addr) |
| return out |
| |
| # Write LD script includes for the given sections using relative offsets |
| def outRelSections(sections, startsym): |
| out = "" |
| for section in sections: |
| out += ". = ( 0x%x - %s ) ;\n" % (section.finalloc, startsym) |
| if section.name == '.rodata.str1.1': |
| out += "_rodata = . ;\n" |
| out += "*(%s)\n" % (section.name,) |
| return out |
| |
| def getSectionsFile(sections, fileid, defaddr=0): |
| sections = [(section.finalloc, section) |
| for section in sections if section.fileid == fileid] |
| sections.sort() |
| sections = [section for addr, section in sections] |
| pos = defaddr |
| if sections: |
| pos = sections[0].finalloc |
| return sections, pos |
| |
| # Layout the 32bit segmented code. This places the code as high as possible. |
| def writeLinkerScripts(sections, entrysym, genreloc, out16, out32seg, out32flat): |
| # Write 16bit linker script |
| sections16, code16_start = getSectionsFile(sections, '16') |
| output = open(out16, 'wb') |
| output.write(COMMONHEADER + outXRefs(sections16) + """ |
| code16_start = 0x%x ; |
| .text16 code16_start : { |
| """ % (code16_start) |
| + outRelSections(sections16, 'code16_start') |
| + """ |
| } |
| """ |
| + COMMONTRAILER) |
| output.close() |
| |
| # Write 32seg linker script |
| sections32seg, code32seg_start = getSectionsFile( |
| sections, '32seg', code16_start) |
| output = open(out32seg, 'wb') |
| output.write(COMMONHEADER + outXRefs(sections32seg) + """ |
| code32seg_start = 0x%x ; |
| .text32seg code32seg_start : { |
| """ % (code32seg_start) |
| + outRelSections(sections32seg, 'code32seg_start') |
| + """ |
| } |
| """ |
| + COMMONTRAILER) |
| output.close() |
| |
| # Write 32flat linker script |
| sections32flat, code32flat_start = getSectionsFile( |
| sections, '32flat', code32seg_start) |
| relocstr = "" |
| relocminalign = 0 |
| if genreloc: |
| # Generate relocations |
| relocstr, size, relocminalign = genRelocs(sections) |
| code32flat_start -= size |
| output = open(out32flat, 'wb') |
| output.write(COMMONHEADER |
| + outXRefs(sections32flat) + """ |
| %s = 0x%x ; |
| _reloc_min_align = 0x%x ; |
| code32flat_start = 0x%x ; |
| .text code32flat_start : { |
| """ % (entrysym.name, |
| entrysym.section.finalloc + entrysym.offset + BUILD_BIOS_ADDR, |
| relocminalign, code32flat_start) |
| + relocstr |
| + """ |
| code32init_start = ABSOLUTE(.) ; |
| """ |
| + outRelSections(getSectionsPrefix(sections32flat, '32init', '') |
| , 'code32flat_start') |
| + """ |
| code32init_end = ABSOLUTE(.) ; |
| """ |
| + outRelSections(getSectionsPrefix(sections32flat, '32flat', '') |
| , 'code32flat_start') |
| + """ |
| . = ( 0x%x - code32flat_start ) ; |
| *(.text32seg) |
| . = ( 0x%x - code32flat_start ) ; |
| *(.text16) |
| code32flat_end = ABSOLUTE(.) ; |
| } :text |
| """ % (code32seg_start + BUILD_BIOS_ADDR, code16_start + BUILD_BIOS_ADDR) |
| + COMMONTRAILER |
| + """ |
| ENTRY(%s) |
| PHDRS |
| { |
| text PT_LOAD AT ( code32flat_start ) ; |
| } |
| """ % (entrysym.name,)) |
| output.close() |
| |
| |
| ###################################################################### |
| # Detection of init code |
| ###################################################################### |
| |
| # Determine init section relocations |
| def genRelocs(sections): |
| absrelocs = [] |
| relrelocs = [] |
| initrelocs = [] |
| minalign = 16 |
| for section in sections: |
| if section.category == '32init' and section.align > minalign: |
| minalign = section.align |
| for reloc in section.relocs: |
| symbol = reloc.symbol |
| if symbol.section is None: |
| continue |
| relocpos = section.finalloc + reloc.offset |
| if (reloc.type == 'R_386_32' and section.category == '32init' |
| and symbol.section.category == '32init'): |
| # Absolute relocation |
| absrelocs.append(relocpos) |
| elif (reloc.type == 'R_386_PC32' and section.category == '32init' |
| and symbol.section.category != '32init'): |
| # Relative relocation |
| relrelocs.append(relocpos) |
| elif (section.category != '32init' |
| and symbol.section.category == '32init'): |
| # Relocation to the init section |
| if section.fileid in ('16', '32seg'): |
| relocpos += BUILD_BIOS_ADDR |
| initrelocs.append(relocpos) |
| absrelocs.sort() |
| relrelocs.sort() |
| initrelocs.sort() |
| out = (" _reloc_abs_start = ABSOLUTE(.) ;\n" |
| + "".join(["LONG(0x%x - code32init_start)\n" % (pos,) |
| for pos in absrelocs]) |
| + " _reloc_abs_end = ABSOLUTE(.) ;\n" |
| + " _reloc_rel_start = ABSOLUTE(.) ;\n" |
| + "".join(["LONG(0x%x - code32init_start)\n" % (pos,) |
| for pos in relrelocs]) |
| + " _reloc_rel_end = ABSOLUTE(.) ;\n" |
| + " _reloc_init_start = ABSOLUTE(.) ;\n" |
| + "".join(["LONG(0x%x - code32flat_start)\n" % (pos,) |
| for pos in initrelocs]) |
| + " _reloc_init_end = ABSOLUTE(.) ;\n") |
| return out, len(absrelocs + relrelocs + initrelocs) * 4, minalign |
| |
| def markRuntime(section, sections): |
| if (section is None or not section.keep or section.category is not None |
| or '.init.' in section.name or section.fileid != '32flat'): |
| return |
| section.category = '32flat' |
| # Recursively mark all sections this section points to |
| for reloc in section.relocs: |
| markRuntime(reloc.symbol.section, sections) |
| |
| def findInit(sections): |
| # Recursively find and mark all "runtime" sections. |
| for section in sections: |
| if '.runtime.' in section.name or '.export.' in section.name: |
| markRuntime(section, sections) |
| for section in sections: |
| if section.category is not None: |
| continue |
| if section.fileid == '32flat': |
| section.category = '32init' |
| else: |
| section.category = section.fileid |
| |
| |
| ###################################################################### |
| # Section garbage collection |
| ###################################################################### |
| |
| CFUNCPREFIX = [('_cfunc16_', 0), ('_cfunc32seg_', 1), ('_cfunc32flat_', 2)] |
| |
| # Find and keep the section associated with a symbol (if available). |
| def keepsymbol(reloc, infos, pos, isxref): |
| symbolname = reloc.symbolname |
| mustbecfunc = 0 |
| for symprefix, needpos in CFUNCPREFIX: |
| if symbolname.startswith(symprefix): |
| if needpos != pos: |
| return -1 |
| symbolname = symbolname[len(symprefix):] |
| mustbecfunc = 1 |
| break |
| symbol = infos[pos][1].get(symbolname) |
| if (symbol is None or symbol.section is None |
| or symbol.section.name.startswith('.discard.')): |
| return -1 |
| isdestcfunc = (symbol.section.name.startswith('.text.') |
| and not symbol.section.name.startswith('.text.asm.')) |
| if ((mustbecfunc and not isdestcfunc) |
| or (not mustbecfunc and isdestcfunc and isxref)): |
| return -1 |
| |
| reloc.symbol = symbol |
| keepsection(symbol.section, infos, pos) |
| return 0 |
| |
| # Note required section, and recursively set all referenced sections |
| # as required. |
| def keepsection(section, infos, pos=0): |
| if section.keep: |
| # Already kept - nothing to do. |
| return |
| section.keep = 1 |
| # Keep all sections that this section points to |
| for reloc in section.relocs: |
| ret = keepsymbol(reloc, infos, pos, 0) |
| if not ret: |
| continue |
| # Not in primary sections - it may be a cross 16/32 reference |
| ret = keepsymbol(reloc, infos, (pos+1)%3, 1) |
| if not ret: |
| continue |
| ret = keepsymbol(reloc, infos, (pos+2)%3, 1) |
| if not ret: |
| continue |
| |
| # Determine which sections are actually referenced and need to be |
| # placed into the output file. |
| def gc(info16, info32seg, info32flat): |
| # infos = ((sections16, symbols16), (sect32seg, sym32seg) |
| # , (sect32flat, sym32flat)) |
| infos = (info16, info32seg, info32flat) |
| # Start by keeping sections that are globally visible. |
| for section in info16[0]: |
| if section.name.startswith('.fixedaddr.') or '.export.' in section.name: |
| keepsection(section, infos) |
| return [section for section in info16[0]+info32seg[0]+info32flat[0] |
| if section.keep] |
| |
| |
| ###################################################################### |
| # Startup and input parsing |
| ###################################################################### |
| |
| class Section: |
| name = size = alignment = fileid = relocs = None |
| finalloc = category = keep = None |
| class Reloc: |
| offset = type = symbolname = symbol = None |
| class Symbol: |
| name = offset = section = None |
| |
| # Read in output from objdump |
| def parseObjDump(file, fileid): |
| # sections = [section, ...] |
| sections = [] |
| sectionmap = {} |
| # symbols[symbolname] = symbol |
| symbols = {} |
| |
| state = None |
| for line in file.readlines(): |
| line = line.rstrip() |
| if line == 'Sections:': |
| state = 'section' |
| continue |
| if line == 'SYMBOL TABLE:': |
| state = 'symbol' |
| continue |
| if line.startswith('RELOCATION RECORDS FOR ['): |
| sectionname = line[24:-2] |
| if sectionname.startswith('.debug_'): |
| # Skip debugging sections (to reduce parsing time) |
| state = None |
| continue |
| state = 'reloc' |
| relocsection = sectionmap[sectionname] |
| continue |
| |
| if state == 'section': |
| try: |
| idx, name, size, vma, lma, fileoff, align = line.split() |
| if align[:3] != '2**': |
| continue |
| section = Section() |
| section.name = name |
| section.size = int(size, 16) |
| section.align = 2**int(align[3:]) |
| section.fileid = fileid |
| section.relocs = [] |
| sections.append(section) |
| sectionmap[name] = section |
| except ValueError: |
| pass |
| continue |
| if state == 'symbol': |
| try: |
| sectionname, size, name = line[17:].split() |
| symbol = Symbol() |
| symbol.size = int(size, 16) |
| symbol.offset = int(line[:8], 16) |
| symbol.name = name |
| symbol.section = sectionmap.get(sectionname) |
| symbols[name] = symbol |
| except ValueError: |
| pass |
| continue |
| if state == 'reloc': |
| try: |
| off, type, symbolname = line.split() |
| reloc = Reloc() |
| reloc.offset = int(off, 16) |
| reloc.type = type |
| reloc.symbolname = symbolname |
| reloc.symbol = symbols.get(symbolname) |
| if reloc.symbol is None: |
| # Some binutils (2.20.1) give section name instead |
| # of a symbol - create a dummy symbol. |
| reloc.symbol = symbol = Symbol() |
| symbol.size = 0 |
| symbol.offset = 0 |
| symbol.name = symbolname |
| symbol.section = sectionmap.get(symbolname) |
| symbols[symbolname] = symbol |
| relocsection.relocs.append(reloc) |
| except ValueError: |
| pass |
| return sections, symbols |
| |
| def main(): |
| # Get output name |
| in16, in32seg, in32flat, out16, out32seg, out32flat = sys.argv[1:] |
| |
| # Read in the objdump information |
| infile16 = open(in16, 'rb') |
| infile32seg = open(in32seg, 'rb') |
| infile32flat = open(in32flat, 'rb') |
| |
| # infoX = (sections, symbols) |
| info16 = parseObjDump(infile16, '16') |
| info32seg = parseObjDump(infile32seg, '32seg') |
| info32flat = parseObjDump(infile32flat, '32flat') |
| |
| # Figure out which sections to keep. |
| sections = gc(info16, info32seg, info32flat) |
| |
| # Separate 32bit flat into runtime and init parts |
| findInit(sections) |
| |
| # Determine the final memory locations of each kept section. |
| doLayout(sections) |
| |
| # Write out linker script files. |
| entrysym = info16[1]['post32'] |
| genreloc = '_reloc_abs_start' in info32flat[1] |
| writeLinkerScripts(sections, entrysym, genreloc, out16, out32seg, out32flat) |
| |
| if __name__ == '__main__': |
| main() |
