diff options
Diffstat (limited to 'lib/hipe/llvm/elf_format.erl')
| -rw-r--r-- | lib/hipe/llvm/elf_format.erl | 237 |
1 files changed, 101 insertions, 136 deletions
diff --git a/lib/hipe/llvm/elf_format.erl b/lib/hipe/llvm/elf_format.erl index 13a00bfd38..e56ccce626 100644 --- a/lib/hipe/llvm/elf_format.erl +++ b/lib/hipe/llvm/elf_format.erl @@ -37,25 +37,32 @@ -export_type([elf/0]). --opaque elf() :: binary(). - -type lp() :: non_neg_integer(). % landing pad -type num() :: non_neg_integer(). -type index() :: non_neg_integer(). -type offset() :: non_neg_integer(). -type size() :: non_neg_integer(). -type start() :: non_neg_integer(). +-type reloc_type() :: atom(). --type info() :: index(). --type nameoff() :: offset(). -type valueoff() :: offset(). -type name() :: string(). +-type tuple(X) :: {} | {X} | {X, X} | tuple(). + %%------------------------------------------------------------------------------ %% Abstract Data Types and Accessors for ELF Structures. %%------------------------------------------------------------------------------ +-record(elf, {file :: binary() + ,sec_idx :: tuple(elf_shdr()) + ,sec_nam :: #{string() => elf_shdr()} + ,sym_idx :: undefined | tuple(elf_sym()) + }). + +-opaque elf() :: #elf{}. + %% File header -record(elf_ehdr, {ident, % ELF identification type, % Object file type @@ -99,29 +106,22 @@ -type elf_shdr() :: #elf_shdr{}. %% Symbol table entries --record(elf_sym, {name :: nameoff(), % Symbol name +-record(elf_sym, {name :: string(), % Symbol name info, % Type and Binding attributes other, % Reserved - shndx, % Section table index + section :: undefined | abs | elf_shdr(), value :: valueoff(), % Symbol value size :: size() % Size of object }). -type elf_sym() :: #elf_sym{}. %% Relocations --ifdef(BIT32). --record(elf_rel, {r_offset :: offset(), % Address of reference - r_info :: info() % Symbol index and type of relocation - }). --type reloc() :: #elf_rel{}. --else. - --record(elf_rela, {r_offset :: offset(), % Address of reference - r_info :: info(), % Symbol index and type of relocation - r_addend :: offset() % Constant part of expression - }). --type reloc() :: #elf_rela{}. --endif. +-record(elf_rel, {offset :: offset() + ,type :: reloc_type() + ,addend :: offset() | undefined + ,symbol :: elf_sym() + }). +-type elf_rel() :: #elf_rel{}. %% %% Program header table %% -record(elf_phdr, {type, % Type of segment @@ -201,11 +201,11 @@ mk_shdr(Name, Type, Flags, Addr, Offset, Size, Link, Info, AddrAlign, EntSize) - %%%------------------------- %%% Symbol Table Entries %%%------------------------- -mk_sym(Name, Info, Other, Shndx, Value, Size) -> +mk_sym(Name, Info, Other, Section, Value, Size) -> #elf_sym{name = Name, info = Info, other = Other, - shndx = Shndx, value = Value, size = Size}. + section = Section, value = Value, size = Size}. --spec sym_name(elf_sym()) -> nameoff(). +-spec sym_name(elf_sym()) -> string(). sym_name(#elf_sym{name = Name}) -> Name. %% -spec sym_value(elf_sym()) -> valueoff(). @@ -214,39 +214,6 @@ sym_name(#elf_sym{name = Name}) -> Name. %% -spec sym_size(elf_sym()) -> size(). %% sym_size(#elf_sym{size = Size}) -> Size. -%%%------------------------- -%%% Relocations -%%%------------------------- - - -%% The following two functions capitalize on the fact that the two kinds of -%% relocation records (for 32- and 64-bit architectures have similar structure. --spec r_offset(reloc()) -> offset(). --spec r_info(reloc()) -> info(). - --ifdef(BIT32). - --spec mk_rel(offset(), info()) -> reloc(). -mk_rel(Offset, Info) -> - #elf_rel{r_offset = Offset, r_info = Info}. - -r_offset(#elf_rel{r_offset = Offset}) -> Offset. -r_info(#elf_rel{r_info = Info}) -> Info. - --else.%%BIT32 - --spec mk_rela(offset(), info(), offset()) -> reloc(). -mk_rela(Offset, Info, Addend) -> - #elf_rela{r_offset = Offset, r_info = Info, r_addend = Addend}. - -r_offset(#elf_rela{r_offset = Offset}) -> Offset. -r_info(#elf_rela{r_info = Info}) -> Info. - --spec rela_addend(reloc()) -> offset(). -rela_addend(#elf_rela{r_addend = Addend}) -> Addend. - --endif.%%BIT32 - %% %%%------------------------- %% %%% GCC exception table %% %%%------------------------- @@ -278,7 +245,14 @@ mk_gccexntab_callsite(Start, Size, LP, Action) -> %% @doc Parses an ELF file. -spec read(binary()) -> elf(). -read(ElfBin) -> ElfBin. +read(ElfBin) -> + Header = extract_header(ElfBin), + [_UndefinedSec|Sections] = extract_shdrtab(ElfBin, Header), + SecNam = maps:from_list( + [{Name, Sec} || Sec = #elf_shdr{name=Name} <- Sections]), + Elf0 = #elf{file=ElfBin, sec_idx=list_to_tuple(Sections), sec_nam=SecNam}, + [_UndefinedSym|Symbols] = extract_symtab(Elf0, extract_strtab(Elf0)), + Elf0#elf{sym_idx=list_to_tuple(Symbols)}. %%------------------------------------------------------------------------------ %% Functions to manipulate the ELF File Header @@ -287,9 +261,9 @@ read(ElfBin) -> ElfBin. %% @doc Extracts the File Header from an ELF formatted object file. Also sets %% the ELF class variable in the process dictionary (used by many functions %% in this and hipe_llvm_main modules). --spec extract_header(elf()) -> elf_ehdr(). -extract_header(Elf) -> - Ehdr_bin = get_binary_segment(Elf, 0, ?ELF_EHDR_SIZE), +-spec extract_header(binary()) -> elf_ehdr(). +extract_header(ElfBin) -> + Ehdr_bin = get_binary_segment(ElfBin, 0, ?ELF_EHDR_SIZE), << %% Structural pattern matching on fields. Ident_bin:?E_IDENT_SIZE/binary, Type:?bits(?E_TYPE_SIZE)/integer-little, @@ -321,14 +295,11 @@ extract_header(Elf) -> -type shdrtab() :: [elf_shdr()]. %% @doc Extracts the Section Header Table from an ELF formated Object File. --spec extract_shdrtab(elf()) -> shdrtab(). -extract_shdrtab(Elf) -> - %% Extract File Header to get info about Section Header Offset (in bytes), - %% Entry Size (in bytes) and Number of entries - #elf_ehdr{shoff = ShOff, shentsize = ShEntsize, shnum = ShNum - ,shstrndx = ShStrNdx} = extract_header(Elf), +-spec extract_shdrtab(binary(), elf_ehdr()) -> shdrtab(). +extract_shdrtab(ElfBin, #elf_ehdr{shoff=ShOff, shentsize=?ELF_SHDRENTRY_SIZE, + shnum=ShNum, shstrndx=ShStrNdx}) -> %% Get actual Section header table (binary) - ShdrBin = get_binary_segment(Elf, ShOff, ShNum * ShEntsize), + ShdrBin = get_binary_segment(ElfBin, ShOff, ShNum * ?ELF_SHDRENTRY_SIZE), %% We need to lookup the offset and size of the section header string table %% before we can fully parse the section table. We compute its offset and %% extract the fields we need here. @@ -338,7 +309,7 @@ extract_shdrtab(Elf) -> ShStrOffset:?bits(?SH_OFFSET_SIZE)/little, ShStrSize:?bits(?SH_SIZE_SIZE)/little, _/binary>> = ShdrBin, - ShStrTab = parse_strtab(get_binary_segment(Elf, ShStrOffset, ShStrSize)), + ShStrTab = parse_strtab(get_binary_segment(ElfBin, ShStrOffset, ShStrSize)), get_shdrtab_entries(ShdrBin, ShStrTab). get_shdrtab_entries(<<>>, _ShStrTab) -> []; @@ -360,24 +331,28 @@ get_shdrtab_entries(ShdrTab, ShStrTab) -> Size, Link, Info, Addralign, Entsize), [Entry | get_shdrtab_entries(Rest, ShStrTab)]. +-spec elf_section(non_neg_integer(), elf()) -> undefined | abs | elf_shdr(). +elf_section(0, #elf{}) -> undefined; +elf_section(?SHN_ABS, #elf{}) -> abs; +elf_section(Index, #elf{sec_idx=SecIdx}) when Index =< tuple_size(SecIdx) -> + element(Index, SecIdx). + %%------------------------------------------------------------------------------ -spec get_tab_entries(elf()) -> [{name(), valueoff(), size()}]. -get_tab_entries(Elf) -> - SymTab = extract_symtab(Elf), - StrTab = extract_strtab(Elf), - [{get_strtab_entry(Name, StrTab), Value, Size div ?ELF_XWORD_SIZE} - || #elf_sym{name = Name, value = Value, size = Size} <- SymTab, - Name =/= 0]. +get_tab_entries(#elf{sym_idx=SymIdx}) -> + [{Name, Value, Size div ?ELF_XWORD_SIZE} + || #elf_sym{name = Name, value = Value, size = Size} + <- tuple_to_list(SymIdx), Name =/= ""]. %%------------------------------------------------------------------------------ %% Functions to manipulate Symbol Table %%------------------------------------------------------------------------------ %% @doc Function that extracts Symbol Table from an ELF Object file. -extract_symtab(Elf) -> +extract_symtab(Elf, StrTab) -> Symtab = extract_segment_by_name(Elf, ?SYMTAB), - [parse_sym(Sym) || <<Sym:?ELF_SYM_SIZE/binary>> <= Symtab]. + [parse_sym(Sym, Elf, StrTab) || <<Sym:?ELF_SYM_SIZE/binary>> <= Symtab]. -ifdef(BIT32). parse_sym(<<%% Structural pattern matching on fields. @@ -386,8 +361,10 @@ parse_sym(<<%% Structural pattern matching on fields. Size:?bits(?ST_SIZE_SIZE)/integer-little, Info:?bits(?ST_INFO_SIZE)/integer-little, Other:?bits(?ST_OTHER_SIZE)/integer-little, - Shndx:?bits(?ST_SHNDX_SIZE)/integer-little>>) -> - mk_sym(Name, Info, Other, Shndx, Value, Size). + Shndx:?bits(?ST_SHNDX_SIZE)/integer-little>>, + Elf, StrTab) -> + mk_sym(get_strtab_entry(Name, StrTab), Info, Other, elf_section(Shndx, Elf), + Value, Size). -else. parse_sym(<<%% Same fields in different order: Name:?bits(?ST_NAME_SIZE)/integer-little, @@ -395,15 +372,17 @@ parse_sym(<<%% Same fields in different order: Other:?bits(?ST_OTHER_SIZE)/integer-little, Shndx:?bits(?ST_SHNDX_SIZE)/integer-little, Value:?bits(?ST_VALUE_SIZE)/integer-little, - Size:?bits(?ST_SIZE_SIZE)/integer-little>>) -> - mk_sym(Name, Info, Other, Shndx, Value, Size). + Size:?bits(?ST_SIZE_SIZE)/integer-little>>, + Elf, StrTab) -> + mk_sym(get_strtab_entry(Name, StrTab), Info, Other, elf_section(Shndx, Elf), + Value, Size). -endif. -%% @doc Extracts a specific entry from the Symbol Table (as binary). -%% This function takes as arguments the Symbol Table (`SymTab') -%% and the entry's serial number and returns that entry (`sym'). -get_symtab_entry(SymTab, EntryNum) -> - lists:nth(EntryNum + 1, SymTab). +%% @doc Extracts a specific entry from the Symbol Table. +-spec elf_symbol(0, elf()) -> undefined; + (pos_integer(), elf()) -> elf_sym(). +elf_symbol(0, #elf{}) -> undefined; +elf_symbol(Index, #elf{sym_idx=SymIdx}) -> element(Index, SymIdx). %%------------------------------------------------------------------------------ %% Functions to manipulate String Table @@ -426,6 +405,12 @@ get_strtab_entry(Offset, StrTab) -> <<_:Offset/binary, StrBin/binary>> = StrTab, bin_get_string(StrBin). +%% @doc Extracts a null-terminated string from a binary. +-spec bin_get_string(binary()) -> string(). +%% FIXME: No regard for encoding (just happens to work for ASCII and Latin-1) +bin_get_string(<<0, _/binary>>) -> []; +bin_get_string(<<Char, Rest/binary>>) -> [Char|bin_get_string(Rest)]. + %%------------------------------------------------------------------------------ %% Functions to manipulate Relocations %%------------------------------------------------------------------------------ @@ -434,50 +419,54 @@ get_strtab_entry(Offset, StrTab) -> %% with all .rela.rodata labels (i.e. constants and literals in code) %% or an empty list if no ".rela.rodata" section exists in code. -spec get_rodata_relocs(elf()) -> [offset()]. --spec get_rela_addends([reloc()]) -> [offset()]. --ifdef(BIT32). -get_rodata_relocs(Elf) -> - [SkipPadding || SkipPadding <- extract_rodata(Elf), SkipPadding =/= 0]. -get_rela_addends(_RelaEntries) -> error(notsup). --else. get_rodata_relocs(Elf) -> get_rela_addends(extract_rela(Elf, ?RODATA)). -get_rela_addends(RelaEntries) -> [rela_addend(E) || E <- RelaEntries]. --endif. +-spec get_rela_addends([elf_rel()]) -> [offset()]. +get_rela_addends(RelaEntries) -> [A || #elf_rel{addend=A} <- RelaEntries]. %% @doc Extract a list of the form `[{SymbolName, Offset}]' with all relocatable %% symbols and their offsets in the code from the ".text" section. -spec get_text_relocs(elf()) -> [{name(), offset()}]. get_text_relocs(Elf) -> - Symtab = extract_symtab(Elf), - Strtab = extract_strtab(Elf), - [begin - %% Find the names of the symbols: - Symbol = get_symtab_entry(Symtab, ?ELF_R_SYM(r_info(E))), - Name = get_strtab_entry(sym_name(Symbol), Strtab), - %% Only care about the name and the offset: - {Name, r_offset(E)} - end || E <- extract_rela(Elf, ?TEXT)]. + [{sym_name(Symbol), Offset} + || #elf_rel{offset=Offset, symbol=Symbol} <- extract_rela(Elf, ?TEXT)]. %% @doc Extract the Relocations segment for section `Name' (that is passed %% as second argument) from an ELF formated Object file binary. --spec extract_rela(elf(), name()) -> [reloc()]. +-spec extract_rela(elf(), name()) -> [elf_rel()]. -ifdef(BIT32). extract_rela(Elf, Name) -> - %% Structural pattern matching on fields of a Rel Entry. - [mk_rel(Offset, Info) + SecData = extract_segment_by_name(Elf, Name), + [#elf_rel{offset=Offset, symbol=elf_symbol(?ELF_R_SYM(Info), Elf), + type=decode_reloc_type(?ELF_R_TYPE(Info)), + addend=read_implicit_addend(Offset, SecData)} || <<Offset:?bits(?R_OFFSET_SIZE)/little, Info:?bits(?R_INFO_SIZE)/little % ELF-32 uses ".rel" >> <= extract_segment_by_name(Elf, ?REL(Name))]. --else. + +%% The only types HiPE knows how to patch +decode_reloc_type(1) -> '32'; +decode_reloc_type(2) -> 'pc32'. + +read_implicit_addend(Offset, Section) -> + %% All x86 relocation types uses 'word32' relocation fields; i.e. 32-bit LE. + <<_:Offset/binary, Addend:32/little, _/binary>> = Section, + Addend. + +-else. %% BIT32 extract_rela(Elf, Name) -> - [mk_rela(Offset, Info, Addend) + [#elf_rel{offset=Offset, symbol=elf_symbol(?ELF_R_SYM(Info), Elf), + type=decode_reloc_type(?ELF_R_TYPE(Info)), addend=Addend} || <<Offset:?bits(?R_OFFSET_SIZE)/little, Info:?bits(?R_INFO_SIZE)/little, Addend:?bits(?R_ADDEND_SIZE)/little % ...while ELF-64 uses ".rela" >> <= extract_segment_by_name(Elf, ?RELA(Name))]. --endif. + +decode_reloc_type(1) -> '64'; +decode_reloc_type(2) -> 'pc32'; +decode_reloc_type(10) -> '32'. +-endif. %% BIT32 %%------------------------------------------------------------------------------ %% Functions to manipulate Executable Code segment @@ -570,21 +559,6 @@ get_gccexntab_callsites(CSTab, Acc) -> get_gccexntab_callsites(More, [GccCS | Acc]). %%------------------------------------------------------------------------------ -%% Functions to manipulate Read-only Data (.rodata) -%%------------------------------------------------------------------------------ --ifdef(BIT32). -extract_rodata(Elf) -> - Rodata_bin = extract_segment_by_name(Elf, ?RODATA), - get_rodata_entries(Rodata_bin, []). - -get_rodata_entries(<<>>, Acc) -> - lists:reverse(Acc); -get_rodata_entries(Rodata_bin, Acc) -> - <<Num:?bits(?ELF_ADDR_SIZE)/integer-little, More/binary>> = Rodata_bin, - get_rodata_entries(More, [Num | Acc]). --endif. - -%%------------------------------------------------------------------------------ %% Helper functions %%------------------------------------------------------------------------------ @@ -604,24 +578,15 @@ get_binary_segment(Bin, Offset, Size) -> %% There are handy macros defined in elf_format.hrl for all Standard %% Section Names. -spec extract_segment_by_name(elf(), string()) -> binary(). -extract_segment_by_name(Elf, SectionName) -> - %% Extract Section Header Table from binary - SHdrTable = extract_shdrtab(Elf), +extract_segment_by_name(#elf{file=ElfBin, sec_nam=SecNam}, SectionName) -> %% Find Section Header Table entry by name - case lists:keyfind(SectionName, #elf_shdr.name, SHdrTable) of - %% Note: Same name. - #elf_shdr{name = SectionName, offset = Offset, size = Size} -> - get_binary_segment(Elf, Offset, Size); - false -> %% Not found. + case SecNam of + #{SectionName := #elf_shdr{offset=Offset, size=Size}} -> + get_binary_segment(ElfBin, Offset, Size); + #{} -> %% Not found. <<>> end. -%% @doc Extracts a null-terminated string from a binary. --spec bin_get_string(binary()) -> string(). -%% FIXME: No regard for encoding (just happens to work for ASCII and Latin-1) -bin_get_string(<<0, _/binary>>) -> []; -bin_get_string(<<Char, Rest/binary>>) -> [Char|bin_get_string(Rest)]. - %% @doc Little-Endian Base 128 (LEB128) Decoder %% This function extracts the <b>first</b> LEB128-encoded integer in a %% binary and returns that integer along with the remaining binary. This is |