From 0a5fcefa31bad39e7473a034c5ec3b4ed0c7f439 Mon Sep 17 00:00:00 2001 From: Ana Pazos Date: Thu, 11 Oct 2018 22:49:13 +0000 Subject: [RISCV] Fix disassembling of fence instruction with invalid field Summary: Instruction with 0 in fence field being disassembled as fence , iorw. Printing "unknown" to match GAS behavior. This bug was uncovered by a LLVM MC Disassembler Protocol Buffer Fuzzer for the RISC-V assembly language. Reviewers: asb Subscribers: rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, mgrang, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, jfb, PkmX, jocewei, asb Differential Revision: https://reviews.llvm.org/D51828 llvm-svn: 344309 --- llvm/lib/Target/RISCV/InstPrinter/RISCVInstPrinter.cpp | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'llvm/lib/Target/RISCV/InstPrinter') diff --git a/llvm/lib/Target/RISCV/InstPrinter/RISCVInstPrinter.cpp b/llvm/lib/Target/RISCV/InstPrinter/RISCVInstPrinter.cpp index aa21cf0e6b4..979c8f4e2fa 100644 --- a/llvm/lib/Target/RISCV/InstPrinter/RISCVInstPrinter.cpp +++ b/llvm/lib/Target/RISCV/InstPrinter/RISCVInstPrinter.cpp @@ -93,6 +93,8 @@ void RISCVInstPrinter::printFenceArg(const MCInst *MI, unsigned OpNo, const MCSubtargetInfo &STI, raw_ostream &O) { unsigned FenceArg = MI->getOperand(OpNo).getImm(); + assert (((FenceArg >> 4) == 0) && "Invalid immediate in printFenceArg"); + if ((FenceArg & RISCVFenceField::I) != 0) O << 'i'; if ((FenceArg & RISCVFenceField::O) != 0) @@ -101,6 +103,8 @@ void RISCVInstPrinter::printFenceArg(const MCInst *MI, unsigned OpNo, O << 'r'; if ((FenceArg & RISCVFenceField::W) != 0) O << 'w'; + if (FenceArg == 0) + O << "unknown"; } void RISCVInstPrinter::printFRMArg(const MCInst *MI, unsigned OpNo, -- cgit v1.2.3