llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-lldb Author: None (dlav-sc) <details> <summary>Changes</summary> lldb-server didn't consider that LR instruction may be followed not only by BNE instruction (takes 4 bytes), but by BNEZ too, which is a compressed instruction (takes 2 bytes). As a result, after BNEZ lldb-server reseived an incorrect PC value and couldn't parse the next instruction opcode. --- Full diff: https://github.com/llvm/llvm-project/pull/127505.diff 1 Files Affected: - (modified) lldb/source/Plugins/Instruction/RISCV/EmulateInstructionRISCV.cpp (+11-6) ``````````diff diff --git a/lldb/source/Plugins/Instruction/RISCV/EmulateInstructionRISCV.cpp b/lldb/source/Plugins/Instruction/RISCV/EmulateInstructionRISCV.cpp index badc7ba36f011..e4de28d97d1ff 100644 --- a/lldb/source/Plugins/Instruction/RISCV/EmulateInstructionRISCV.cpp +++ b/lldb/source/Plugins/Instruction/RISCV/EmulateInstructionRISCV.cpp @@ -349,9 +349,10 @@ bool AtomicSequence(EmulateInstructionRISCV &emulator) { if (!inst || (!std::holds_alternative<LR_W>(inst->decoded) && !std::holds_alternative<LR_D>(inst->decoded))) return false; + current_pc += 4; - // The second instruction should be BNE to exit address - inst = emulator.ReadInstructionAt(current_pc += 4); + // The second instruction should be BNE or C.BNEZ to exit address + inst = emulator.ReadInstructionAt(current_pc); if (!inst || !std::holds_alternative<B>(inst->decoded)) return false; auto bne_exit = std::get<B>(inst->decoded); @@ -359,15 +360,18 @@ bool AtomicSequence(EmulateInstructionRISCV &emulator) { return false; // save the exit address to check later const auto exit_pc = current_pc + SextW(bne_exit.imm); + // Can be C.BNEZ (2 bytes) or BNE (4 bytes) + current_pc += inst->is_rvc ? 2 : 4; // The third instruction should be SC.W or SC.D - inst = emulator.ReadInstructionAt(current_pc += 4); + inst = emulator.ReadInstructionAt(current_pc); if (!inst || (!std::holds_alternative<SC_W>(inst->decoded) && !std::holds_alternative<SC_D>(inst->decoded))) return false; + current_pc += 4; - // The fourth instruction should be BNE to entry address - inst = emulator.ReadInstructionAt(current_pc += 4); + // The fourth instruction should be BNE or C.BNEZ to entry address + inst = emulator.ReadInstructionAt(current_pc); if (!inst || !std::holds_alternative<B>(inst->decoded)) return false; auto bne_start = std::get<B>(inst->decoded); @@ -375,8 +379,9 @@ bool AtomicSequence(EmulateInstructionRISCV &emulator) { return false; if (entry_pc != current_pc + SextW(bne_start.imm)) return false; + // Can be C.BNEZ (2 bytes) or BNE (4 bytes) + current_pc += inst->is_rvc ? 2 : 4; - current_pc += 4; // check the exit address and jump to it return exit_pc == current_pc && emulator.WritePC(current_pc); } `````````` </details> https://github.com/llvm/llvm-project/pull/127505 _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
