[llvm-objcopy][MachO] Support indirect symbol table
Summary:
Parse the indirect symbol table and update the indexes of
symbol entries in the table in the writer in case they have
been changed.
Reviewers: alexshap, rupprecht, jhenderson
Reviewed By: alexshap, rupprecht
Subscribers: jakehehrlich, abrachet, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66280
diff --git a/llvm/tools/llvm-objcopy/MachO/MachOReader.cpp b/llvm/tools/llvm-objcopy/MachO/MachOReader.cpp
index ed2b3eb..7e2ebdc 100644
--- a/llvm/tools/llvm-objcopy/MachO/MachOReader.cpp
+++ b/llvm/tools/llvm-objcopy/MachO/MachOReader.cpp
@@ -256,9 +256,16 @@
void MachOReader::readIndirectSymbolTable(Object &O) const {
MachO::dysymtab_command DySymTab = MachOObj.getDysymtabLoadCommand();
- for (uint32_t i = 0; i < DySymTab.nindirectsyms; ++i)
- O.IndirectSymTable.Symbols.push_back(
- MachOObj.getIndirectSymbolTableEntry(DySymTab, i));
+ constexpr uint32_t AbsOrLocalMask =
+ MachO::INDIRECT_SYMBOL_LOCAL | MachO::INDIRECT_SYMBOL_ABS;
+ for (uint32_t i = 0; i < DySymTab.nindirectsyms; ++i) {
+ uint32_t Index = MachOObj.getIndirectSymbolTableEntry(DySymTab, i);
+ if ((Index & AbsOrLocalMask) != 0)
+ O.IndirectSymTable.Symbols.emplace_back(Index, None);
+ else
+ O.IndirectSymTable.Symbols.emplace_back(
+ Index, O.SymTable.getSymbolByIndex(Index));
+ }
}
std::unique_ptr<Object> MachOReader::create() const {
diff --git a/llvm/tools/llvm-objcopy/MachO/MachOWriter.cpp b/llvm/tools/llvm-objcopy/MachO/MachOWriter.cpp
index 4ec91cc..59d57f7 100644
--- a/llvm/tools/llvm-objcopy/MachO/MachOWriter.cpp
+++ b/llvm/tools/llvm-objcopy/MachO/MachOWriter.cpp
@@ -369,11 +369,14 @@
O.LoadCommands[*O.DySymTabCommandIndex]
.MachOLoadCommand.dysymtab_command_data;
- char *Out = (char *)B.getBufferStart() + DySymTabCommand.indirectsymoff;
- assert((DySymTabCommand.nindirectsyms == O.IndirectSymTable.Symbols.size()) &&
- "Incorrect indirect symbol table size");
- memcpy(Out, O.IndirectSymTable.Symbols.data(),
- sizeof(uint32_t) * O.IndirectSymTable.Symbols.size());
+ uint32_t *Out =
+ (uint32_t *)(B.getBufferStart() + DySymTabCommand.indirectsymoff);
+ for (const IndirectSymbolEntry &Sym : O.IndirectSymTable.Symbols) {
+ uint32_t Entry = (Sym.Symbol) ? (*Sym.Symbol)->Index : Sym.OriginalIndex;
+ if (IsLittleEndian != sys::IsLittleEndianHost)
+ sys::swapByteOrder(Entry);
+ *Out++ = Entry;
+ }
}
void MachOWriter::writeDataInCodeData() {
diff --git a/llvm/tools/llvm-objcopy/MachO/Object.h b/llvm/tools/llvm-objcopy/MachO/Object.h
index 36b0f7e..bf80253 100644
--- a/llvm/tools/llvm-objcopy/MachO/Object.h
+++ b/llvm/tools/llvm-objcopy/MachO/Object.h
@@ -112,8 +112,21 @@
const SymbolEntry *getSymbolByIndex(uint32_t Index) const;
};
+struct IndirectSymbolEntry {
+ // The original value in an indirect symbol table. Higher bits encode extra
+ // information (INDIRECT_SYMBOL_LOCAL and INDIRECT_SYMBOL_ABS).
+ uint32_t OriginalIndex;
+ /// The Symbol referenced by this entry. It's None if the index is
+ /// INDIRECT_SYMBOL_LOCAL or INDIRECT_SYMBOL_ABS.
+ Optional<const SymbolEntry *> Symbol;
+
+ IndirectSymbolEntry(uint32_t OriginalIndex,
+ Optional<const SymbolEntry *> Symbol)
+ : OriginalIndex(OriginalIndex), Symbol(Symbol) {}
+};
+
struct IndirectSymbolTable {
- std::vector<uint32_t> Symbols;
+ std::vector<IndirectSymbolEntry> Symbols;
};
/// The location of the string table inside the binary is described by LC_SYMTAB