diff options
Diffstat (limited to 'llvm/tools/llvm-objdump/llvm-objdump.cpp')
| -rw-r--r-- | llvm/tools/llvm-objdump/llvm-objdump.cpp | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp index d130e5c..c27e487 100644 --- a/llvm/tools/llvm-objdump/llvm-objdump.cpp +++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp @@ -1429,10 +1429,37 @@ static void disassembleObject(const Target *TheTarget, const ObjectFile *Obj, continue; } - // Some targets (like WebAssembly) have a special prelude at the start - // of each symbol. - DisAsm->onSymbolStart(SymbolName, Size, Bytes.slice(Start, End - Start), - SectionAddr + Start, CommentStream); + auto Status = DisAsm->onSymbolStart(SymbolName, Size, + Bytes.slice(Start, End - Start), + SectionAddr + Start, CommentStream); + // To have round trippable disassembly, we fall back to decoding the + // remaining bytes as instructions. + // + // If there is a failure, we disassemble the failed region as bytes before + // falling back. The target is expected to print nothing in this case. + // + // If there is Success or SoftFail i.e no 'real' failure, we go ahead by + // Size bytes before falling back. + // So if the entire symbol is 'eaten' by the target: + // Start += Size // Now Start = End and we will never decode as + // // instructions + // + // Right now, most targets return None i.e ignore to treat a symbol + // separately. But WebAssembly decodes preludes for some symbols. + // + if (Status.hasValue()) { + if (Status.getValue() == MCDisassembler::Fail) { + outs() << "// Error in decoding " << SymbolName + << " : Decoding failed region as bytes.\n"; + for (uint64_t I = 0; I < Size; ++I) { + outs() << "\t.byte\t " << format_hex(Bytes[I], 1, /*Upper=*/true) + << "\n"; + } + } + } else { + Size = 0; + } + Start += Size; Index = Start; |