[llvm] r212568 - Add support for BSD format Archive map symbols (aka the table of contents
Rafael Espíndola
rafael.espindola at gmail.com
Wed Jul 9 12:23:22 PDT 2014
thanks!
On 8 July 2014 18:10, Kevin Enderby <enderby at apple.com> wrote:
> Author: enderby
> Date: Tue Jul 8 17:10:02 2014
> New Revision: 212568
>
> URL: http://llvm.org/viewvc/llvm-project?rev=212568&view=rev
> Log:
> Add support for BSD format Archive map symbols (aka the table of contents
> from a __.SYMDEF or "__.SYMDEF SORTED" archive member).
>
> Modified:
> llvm/trunk/lib/Object/Archive.cpp
> llvm/trunk/test/Object/archive-symtab.test
>
> Modified: llvm/trunk/lib/Object/Archive.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/Archive.cpp?rev=212568&r1=212567&r2=212568&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Object/Archive.cpp (original)
> +++ llvm/trunk/lib/Object/Archive.cpp Tue Jul 8 17:10:02 2014
> @@ -339,7 +339,14 @@ ErrorOr<Archive::child_iterator> Archive
> Offset = *(reinterpret_cast<const support::ubig32_t*>(Offsets)
> + SymbolIndex);
> } else if (Parent->kind() == K_BSD) {
> - llvm_unreachable("BSD format is not supported");
> + // The SymbolIndex is an index into the ranlib structs that start at
> + // Offsets (the first uint32_t is the number of bytes of the ranlib
> + // structs). The ranlib structs are a pair of uint32_t's the first
> + // being a string table offset and the second being the offset into
> + // the archive of the member that defines the symbol. Which is what
> + // is needed here.
> + Offset = *(reinterpret_cast<const support::ulittle32_t *>(Offsets) +
> + (SymbolIndex * 2) + 1);
> } else {
> uint32_t MemberCount = *reinterpret_cast<const support::ulittle32_t*>(Buf);
>
> @@ -377,9 +384,43 @@ ErrorOr<Archive::child_iterator> Archive
>
> Archive::Symbol Archive::Symbol::getNext() const {
> Symbol t(*this);
> - // Go to one past next null.
> - t.StringIndex =
> - Parent->SymbolTable->getBuffer().find('\0', t.StringIndex) + 1;
> + if (Parent->kind() == K_BSD) {
> + // t.StringIndex is an offset from the start of the __.SYMDEF or
> + // "__.SYMDEF SORTED" member into the string table for the ranlib
> + // struct indexed by t.SymbolIndex . To change t.StringIndex to the
> + // offset in the string table for t.SymbolIndex+1 we subtract the
> + // its offset from the start of the string table for t.SymbolIndex
> + // and add the offset of the string table for t.SymbolIndex+1.
> +
> + // The __.SYMDEF or "__.SYMDEF SORTED" member starts with a uint32_t
> + // which is the number of bytes of ranlib structs that follow. The ranlib
> + // structs are a pair of uint32_t's the first being a string table offset
> + // and the second being the offset into the archive of the member that
> + // define the symbol. After that the next uint32_t is the byte count of
> + // the string table followed by the string table.
> + const char *Buf = Parent->SymbolTable->getBuffer().begin();
> + uint32_t RanlibCount = 0;
> + RanlibCount = (*reinterpret_cast<const support::ulittle32_t *>(Buf)) /
> + (sizeof(uint32_t) * 2);
> + // If t.SymbolIndex + 1 will be past the count of symbols (the RanlibCount)
> + // don't change the t.StringIndex as we don't want to reference a ranlib
> + // past RanlibCount.
> + if (t.SymbolIndex + 1 < RanlibCount) {
> + const char *Ranlibs = Buf + 4;
> + uint32_t CurRanStrx = 0;
> + uint32_t NextRanStrx = 0;
> + CurRanStrx = *(reinterpret_cast<const support::ulittle32_t *>(Ranlibs) +
> + (t.SymbolIndex * 2));
> + NextRanStrx = *(reinterpret_cast<const support::ulittle32_t *>(Ranlibs) +
> + ((t.SymbolIndex + 1) * 2));
> + t.StringIndex -= CurRanStrx;
> + t.StringIndex += NextRanStrx;
> + }
> + } else {
> + // Go to one past next null.
> + t.StringIndex =
> + Parent->SymbolTable->getBuffer().find('\0', t.StringIndex) + 1;
> + }
> ++t.SymbolIndex;
> return t;
> }
> @@ -394,7 +435,22 @@ Archive::symbol_iterator Archive::symbol
> symbol_count = *reinterpret_cast<const support::ubig32_t*>(buf);
> buf += sizeof(uint32_t) + (symbol_count * (sizeof(uint32_t)));
> } else if (kind() == K_BSD) {
> - llvm_unreachable("BSD archive format is not supported");
> + // The __.SYMDEF or "__.SYMDEF SORTED" member starts with a uint32_t
> + // which is the number of bytes of ranlib structs that follow. The ranlib
> + // structs are a pair of uint32_t's the first being a string table offset
> + // and the second being the offset into the archive of the member that
> + // define the symbol. After that the next uint32_t is the byte count of
> + // the string table followed by the string table.
> + uint32_t ranlib_count = 0;
> + ranlib_count = (*reinterpret_cast<const support::ulittle32_t *>(buf)) /
> + (sizeof(uint32_t) * 2);
> + const char *ranlibs = buf + 4;
> + uint32_t ran_strx = 0;
> + ran_strx = *(reinterpret_cast<const support::ulittle32_t *>(ranlibs));
> + buf += sizeof(uint32_t) + (ranlib_count * (2 * (sizeof(uint32_t))));
> + // Skip the byte count of the string table.
> + buf += sizeof(uint32_t);
> + buf += ran_strx;
> } else {
> uint32_t member_count = 0;
> uint32_t symbol_count = 0;
> @@ -416,7 +472,8 @@ Archive::symbol_iterator Archive::symbol
> if (kind() == K_GNU) {
> symbol_count = *reinterpret_cast<const support::ubig32_t*>(buf);
> } else if (kind() == K_BSD) {
> - llvm_unreachable("BSD archive format is not supported");
> + symbol_count = (*reinterpret_cast<const support::ulittle32_t *>(buf)) /
> + (sizeof(uint32_t) * 2);
> } else {
> uint32_t member_count = 0;
> member_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
>
> Modified: llvm/trunk/test/Object/archive-symtab.test
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Object/archive-symtab.test?rev=212568&r1=212567&r2=212568&view=diff
> ==============================================================================
> --- llvm/trunk/test/Object/archive-symtab.test (original)
> +++ llvm/trunk/test/Object/archive-symtab.test Tue Jul 8 17:10:02 2014
> @@ -59,3 +59,9 @@ RUN: llvm-nm -s %t.a | FileCheck %s --ch
>
> RUN: llvm-ranlib %t.a
> RUN: llvm-nm -s %t.a | FileCheck %s
> +
> +RUN: llvm-nm -s %p/Inputs/macho-archive-x86_64.a | FileCheck %s --check-prefix=BSD-MachO
> +
> +BSD-MachO: Archive map
> +BSD-MachO: _bar in bar.o
> +BSD-MachO: _foo in foo.o
>
>
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