| #!/usr/bin/env python |
| # Script to analyze code and arrange ld sections. |
| # |
| # Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net> |
| # |
| # This file may be distributed under the terms of the GNU GPLv3 license. |
| |
| import sys |
| |
| # Align 'pos' to 'alignbytes' offset |
| def alignpos(pos, alignbytes): |
| mask = alignbytes - 1 |
| return (pos + mask) & ~mask |
| |
| # 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 = """ |
| } |
| """ |
| |
| |
| ###################################################################### |
| # 16bit fixed address section fitting |
| ###################################################################### |
| |
| # Get the maximum start position for a list of sections that end at an |
| # address. |
| def getSectionsStart(sections, endaddr, minalign=1): |
| totspace = 0 |
| for size, align, name in sections: |
| if align > minalign: |
| minalign = align |
| totspace = alignpos(totspace, align) + size |
| return (endaddr - totspace) / minalign * minalign |
| |
| # Write LD script includes for the given sections |
| def outSections(file, sections): |
| for size, align, name in sections: |
| file.write("*(%s)\n" % (name,)) |
| |
| # The 16bit code can't exceed 64K of space. |
| MAXPOS = 64*1024 |
| |
| # 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 doLayout16(sections, outname): |
| textsections = [] |
| rodatasections = [] |
| datasections = [] |
| # fixedsections = [(addr, sectioninfo, extasectionslist), ...] |
| fixedsections = [] |
| # canrelocate = [(sectioninfo, list), ...] |
| canrelocate = [] |
| |
| # Find desired sections. |
| for section in sections: |
| size, align, name = section |
| if name[:11] == '.fixedaddr.': |
| addr = int(name[11:], 16) |
| fixedsections.append((addr, section, [])) |
| if align != 1: |
| print "Error: Fixed section %s has non-zero alignment (%d)" % ( |
| name, align) |
| sys.exit(1) |
| if name[:6] == '.text.': |
| textsections.append(section) |
| canrelocate.append((section, textsections)) |
| if name[:17] == '.rodata.__func__.' or name == '.rodata.str1.1': |
| rodatasections.append(section) |
| #canrelocate.append((section, rodatasections)) |
| if name[:8] == '.data16.': |
| datasections.append(section) |
| #canrelocate.append((section, datasections)) |
| |
| # Find freespace in fixed address area |
| fixedsections.sort() |
| # fixedAddr = [(freespace, sectioninfo), ...] |
| fixedAddr = [] |
| for i in range(len(fixedsections)): |
| fixedsectioninfo = fixedsections[i] |
| addr, section, extrasectionslist = fixedsectioninfo |
| if i == len(fixedsections) - 1: |
| nextaddr = MAXPOS |
| else: |
| nextaddr = fixedsections[i+1][0] |
| avail = nextaddr - addr - section[0] |
| fixedAddr.append((avail, fixedsectioninfo)) |
| |
| # Attempt to fit other sections into fixed area |
| fixedAddr.sort() |
| canrelocate.sort() |
| totalused = 0 |
| for freespace, fixedsectioninfo in fixedAddr: |
| fixedaddr, fixedsection, extrasections = fixedsectioninfo |
| addpos = fixedaddr + fixedsection[0] |
| totalused += fixedsection[0] |
| nextfixedaddr = addpos + freespace |
| # print "Filling section %x uses %d, next=%x, available=%d" % ( |
| # fixedaddr, fixedsection[0], nextfixedaddr, freespace) |
| while 1: |
| canfit = None |
| for fixedaddrinfo in canrelocate: |
| fitsection, inlist = fixedaddrinfo |
| fitsize, fitalign, fitname = fitsection |
| if addpos + fitsize > nextfixedaddr: |
| # Can't fit and nothing else will fit. |
| break |
| fitnextaddr = alignpos(addpos, fitalign) + fitsize |
| # print "Test %s - %x vs %x" % ( |
| # fitname, fitnextaddr, nextfixedaddr) |
| if fitnextaddr > nextfixedaddr: |
| # This item can't fit. |
| continue |
| canfit = (fitnextaddr, fixedaddrinfo) |
| if canfit is None: |
| break |
| # Found a section that can fit. |
| fitnextaddr, fixedaddrinfo = canfit |
| canrelocate.remove(fixedaddrinfo) |
| fitsection, inlist = fixedaddrinfo |
| inlist.remove(fitsection) |
| extrasections.append(fitsection) |
| addpos = fitnextaddr |
| totalused += fitsection[0] |
| # print " Adding %s (size %d align %d) pos=%x avail=%d" % ( |
| # fitsection[2], fitsection[0], fitsection[1] |
| # , fitnextaddr, nextfixedaddr - fitnextaddr) |
| firstfixed = fixedsections[0][0] |
| |
| # Report stats |
| total = MAXPOS-firstfixed |
| slack = total - totalused |
| print ("Fixed space: 0x%x-0x%x total: %d slack: %d" |
| " Percent slack: %.1f%%" % ( |
| firstfixed, MAXPOS, total, slack, |
| (float(slack) / total) * 100.0)) |
| |
| # Find start positions |
| text16_start = getSectionsStart(textsections, firstfixed) |
| data16_start = getSectionsStart(rodatasections + datasections, text16_start) |
| |
| # Write header and regular sections |
| output = open(outname, 'wb') |
| output.write(COMMONHEADER + """ |
| data16_start = 0x%x ; |
| .data16 data16_start : { |
| """ % data16_start) |
| outSections(output, datasections) |
| output.write("code16_rodata = . ;\n") |
| outSections(output, rodatasections) |
| output.write(""" |
| } |
| |
| text16_start = 0x%x ; |
| .text16 text16_start : { |
| """ % text16_start) |
| outSections(output, textsections) |
| |
| # Write fixed sections |
| for addr, section, extrasections in fixedsections: |
| name = section[2] |
| output.write(". = ( 0x%x - text16_start ) ;\n" % (addr,)) |
| output.write("*(%s)\n" % (name,)) |
| for extrasection in extrasections: |
| output.write("*(%s)\n" % (extrasection[2],)) |
| |
| # Write trailer |
| output.write(""" |
| text16_end = ABSOLUTE(.) ; |
| } |
| |
| /* Discard regular data sections to force a link error if |
| * 16bit code attempts to access data not marked with VAR16 |
| */ |
| /DISCARD/ : { *(.text*) *(.rodata*) *(.data*) *(.bss*) *(COMMON) } |
| """ + COMMONTRAILER) |
| |
| return data16_start |
| |
| |
| ###################################################################### |
| # 32bit section outputting |
| ###################################################################### |
| |
| # Return the subset of sections with a given name prefix |
| def getSectionsPrefix(sections, prefix): |
| lp = len(prefix) |
| out = [] |
| for size, align, name in sections: |
| if name[:lp] == prefix: |
| out.append((size, align, name)) |
| return out |
| |
| # Layout the 32bit segmented code. This places the code as high as possible. |
| def doLayout32seg(sections, outname, endat): |
| # Find sections to output |
| textsections = getSectionsPrefix(sections, '.text.') |
| rodatasections = (getSectionsPrefix(sections, '.rodata.str1.1') |
| + getSectionsPrefix(sections, '.rodata.__func__.')) |
| datasections = getSectionsPrefix(sections, '.data32seg.') |
| startat = getSectionsStart( |
| textsections + rodatasections + datasections, endat) |
| |
| # Write sections |
| output = open(outname, 'wb') |
| output.write(COMMONHEADER + """ |
| code32seg_start = 0x%x ; |
| .text32seg code32seg_start : { |
| freespace_end = . ; |
| """ % startat) |
| |
| outSections(output, textsections) |
| output.write("code32seg_rodata = . ;\n") |
| outSections(output, rodatasections) |
| outSections(output, datasections) |
| |
| output.write(""" |
| code32seg_end = ABSOLUTE(.) ; |
| } |
| /DISCARD/ : { *(.text*) *(.rodata*) *(.data*) *(.bss*) *(COMMON) } |
| """ + COMMONTRAILER) |
| return startat |
| |
| # Layout the 32bit flat code. This places the code as high as possible. |
| def doLayout32flat(sections, outname, endat): |
| endat += 0xf0000 |
| # Find sections to output |
| textsections = getSectionsPrefix(sections, '.text.') |
| rodatasections = getSectionsPrefix(sections, '.rodata') |
| datasections = getSectionsPrefix(sections, '.data.') |
| bsssections = getSectionsPrefix(sections, '.bss.') |
| startat = getSectionsStart( |
| textsections + rodatasections + datasections + bsssections, endat, 512) |
| |
| # Write sections |
| output = open(outname, 'wb') |
| output.write(COMMONHEADER + """ |
| code32flat_start = 0x%x ; |
| .text32flat code32flat_start : { |
| """ % startat) |
| |
| outSections(output, textsections) |
| output.write("code32_rodata = . ;\n") |
| outSections(output, rodatasections) |
| outSections(output, datasections) |
| outSections(output, bsssections) |
| |
| output.write(""" |
| freespace_start = . ; |
| code32flat_end = ABSOLUTE(.) ; |
| } |
| """ + COMMONTRAILER) |
| return startat |
| |
| |
| ###################################################################### |
| # Section garbage collection |
| ###################################################################### |
| |
| def getSectionsList(info, names): |
| out = [] |
| for i in info[0]: |
| size, align, section = i |
| if section not in names: |
| # print "gc", section |
| continue |
| out.append(i) |
| return out |
| |
| # Find and keep the section associated with a symbol (if available). |
| def keepsymbol(symbol, infos, pos): |
| addr, section = infos[pos][1].get(symbol, (None, None)) |
| if section is None or '*' in section or section[:9] == '.discard.': |
| return -1 |
| keepsection(section, infos, pos) |
| return 0 |
| |
| # Note required section, and recursively set all referenced sections |
| # as required. |
| def keepsection(name, infos, pos=0): |
| if name in infos[pos][3]: |
| # Already kept - nothing to do. |
| return |
| infos[pos][3].append(name) |
| relocs = infos[pos][2].get(name) |
| if relocs is None: |
| return |
| # Keep all sections that this section points to |
| for symbol in relocs: |
| ret = keepsymbol(symbol, infos, pos) |
| if not ret: |
| continue |
| # Not in primary sections - it may be a cross 16/32 reference |
| ret = keepsymbol(symbol, infos, (pos+1)%3) |
| if not ret: |
| continue |
| ret = keepsymbol(symbol, infos, (pos+2)%3) |
| 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 = ((sections, symbols, relocs, keep sections), ...) |
| infos = ((info16[0], info16[1], info16[2], []), |
| (info32seg[0], info32seg[1], info32seg[2], []), |
| (info32flat[0], info32flat[1], info32flat[2], [])) |
| # Start by keeping sections that are globally visible. |
| for size, align, section in info16[0]: |
| if section[:11] == '.fixedaddr.' or '.export.' in section: |
| keepsection(section, infos) |
| # Return sections found. |
| sections16 = getSectionsList(info16, infos[0][3]) |
| sections32seg = getSectionsList(info32seg, infos[1][3]) |
| sections32flat = getSectionsList(info32flat, infos[2][3]) |
| return sections16, sections32seg, sections32flat |
| |
| |
| ###################################################################### |
| # Startup and input parsing |
| ###################################################################### |
| |
| # Read in output from objdump |
| def parseObjDump(file): |
| # sections = [(size, align, section), ...] |
| sections = [] |
| # symbols[symbol] = section |
| symbols = {} |
| # relocs[section] = [symbol, ...] |
| relocs = {} |
| |
| 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[:24] == 'RELOCATION RECORDS FOR [': |
| state = 'reloc' |
| relocsection = line[24:-2] |
| continue |
| |
| if state == 'section': |
| try: |
| idx, name, size, vma, lma, fileoff, align = line.split() |
| if align[:3] != '2**': |
| continue |
| sections.append((int(size, 16), 2**int(align[3:]), name)) |
| except: |
| pass |
| continue |
| if state == 'symbol': |
| try: |
| section, off, symbol = line[17:].split() |
| off = int(off, 16) |
| addr = int(line[:8], 16) |
| symbols[symbol] = addr, section |
| except: |
| pass |
| continue |
| if state == 'reloc': |
| try: |
| off, type, symbol = line.split() |
| off = int(off, 16) |
| relocs.setdefault(relocsection, []).append(symbol) |
| except: |
| pass |
| return sections, symbols, relocs |
| |
| def main(): |
| # Get output name |
| in16, in32seg, in32flat, out16, out32seg, out32flat = sys.argv[1:] |
| |
| infile16 = open(in16, 'rb') |
| infile32seg = open(in32seg, 'rb') |
| infile32flat = open(in32flat, 'rb') |
| |
| info16 = parseObjDump(infile16) |
| info32seg = parseObjDump(infile32seg) |
| info32flat = parseObjDump(infile32flat) |
| |
| sections16, sections32seg, sections32flat = gc(info16, info32seg, info32flat) |
| |
| start16 = doLayout16(sections16, out16) |
| start32seg = doLayout32seg(sections32seg, out32seg, start16) |
| doLayout32flat(sections32flat, out32flat, start32seg) |
| |
| if __name__ == '__main__': |
| main() |