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Diffstat (limited to 'source/Plugins/Architecture/Mips/ArchitectureMips.cpp')
| -rw-r--r-- | source/Plugins/Architecture/Mips/ArchitectureMips.cpp | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/source/Plugins/Architecture/Mips/ArchitectureMips.cpp b/source/Plugins/Architecture/Mips/ArchitectureMips.cpp new file mode 100644 index 0000000000000..0cbbd99223213 --- /dev/null +++ b/source/Plugins/Architecture/Mips/ArchitectureMips.cpp @@ -0,0 +1,241 @@ +//===-- ArchitectureMips.cpp -------------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#include "Plugins/Architecture/Mips/ArchitectureMips.h" +#include "lldb/Core/Address.h" +#include "lldb/Core/Disassembler.h" +#include "lldb/Core/Module.h" +#include "lldb/Core/PluginManager.h" +#include "lldb/Symbol/Function.h" +#include "lldb/Symbol/SymbolContext.h" +#include "lldb/Target/SectionLoadList.h" +#include "lldb/Target/Target.h" +#include "lldb/Utility/ArchSpec.h" +#include "lldb/Utility/Log.h" + +using namespace lldb_private; +using namespace lldb; + +ConstString ArchitectureMips::GetPluginNameStatic() { + return ConstString("mips"); +} + +void ArchitectureMips::Initialize() { + PluginManager::RegisterPlugin(GetPluginNameStatic(), + "Mips-specific algorithms", + &ArchitectureMips::Create); +} + +void ArchitectureMips::Terminate() { + PluginManager::UnregisterPlugin(&ArchitectureMips::Create); +} + +std::unique_ptr<Architecture> ArchitectureMips::Create(const ArchSpec &arch) { + return arch.IsMIPS() ? + std::unique_ptr<Architecture>(new ArchitectureMips(arch)) : nullptr; +} + +ConstString ArchitectureMips::GetPluginName() { return GetPluginNameStatic(); } +uint32_t ArchitectureMips::GetPluginVersion() { return 1; } + +addr_t ArchitectureMips::GetCallableLoadAddress(addr_t code_addr, + AddressClass addr_class) const { + bool is_alternate_isa = false; + + switch (addr_class) { + case AddressClass::eData: + case AddressClass::eDebug: + return LLDB_INVALID_ADDRESS; + case AddressClass::eCodeAlternateISA: + is_alternate_isa = true; + break; + default: break; + } + + if ((code_addr & 2ull) || is_alternate_isa) + return code_addr | 1u; + return code_addr; +} + +addr_t ArchitectureMips::GetOpcodeLoadAddress(addr_t opcode_addr, + AddressClass addr_class) const { + switch (addr_class) { + case AddressClass::eData: + case AddressClass::eDebug: + return LLDB_INVALID_ADDRESS; + default: break; + } + return opcode_addr & ~(1ull); +} + +lldb::addr_t ArchitectureMips::GetBreakableLoadAddress(lldb::addr_t addr, + Target &target) const { + + Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_BREAKPOINTS)); + + Address resolved_addr; + + SectionLoadList §ion_load_list = target.GetSectionLoadList(); + if (section_load_list.IsEmpty()) + // No sections are loaded, so we must assume we are not running yet and + // need to operate only on file address. + target.ResolveFileAddress(addr, resolved_addr); + else + target.ResolveLoadAddress(addr, resolved_addr); + + addr_t current_offset = 0; + + // Get the function boundaries to make sure we don't scan back before the + // beginning of the current function. + ModuleSP temp_addr_module_sp(resolved_addr.GetModule()); + if (temp_addr_module_sp) { + SymbolContext sc; + SymbolContextItem resolve_scope = + eSymbolContextFunction | eSymbolContextSymbol; + temp_addr_module_sp->ResolveSymbolContextForAddress(resolved_addr, + resolve_scope, sc); + Address sym_addr; + if (sc.function) + sym_addr = sc.function->GetAddressRange().GetBaseAddress(); + else if (sc.symbol) + sym_addr = sc.symbol->GetAddress(); + + addr_t function_start = sym_addr.GetLoadAddress(&target); + if (function_start == LLDB_INVALID_ADDRESS) + function_start = sym_addr.GetFileAddress(); + + if (function_start) + current_offset = addr - function_start; + } + + // If breakpoint address is start of function then we dont have to do + // anything. + if (current_offset == 0) + return addr; + + ExecutionContext ctx; + target.CalculateExecutionContext(ctx); + auto insn = GetInstructionAtAddress(ctx, current_offset, addr); + + if (nullptr == insn || !insn->HasDelaySlot()) + return addr; + + // Adjust the breakable address + uint64_t breakable_addr = addr - insn->GetOpcode().GetByteSize(); + if (log) + log->Printf("Target::%s Breakpoint at 0x%8.8" PRIx64 + " is adjusted to 0x%8.8" PRIx64 " due to delay slot\n", + __FUNCTION__, addr, breakable_addr); + + return breakable_addr; +} + +Instruction *ArchitectureMips::GetInstructionAtAddress( + const ExecutionContext &exe_ctx, const Address &resolved_addr, + addr_t symbol_offset) const { + + auto loop_count = symbol_offset / 2; + + uint32_t arch_flags = m_arch.GetFlags(); + bool IsMips16 = arch_flags & ArchSpec::eMIPSAse_mips16; + bool IsMicromips = arch_flags & ArchSpec::eMIPSAse_micromips; + + if (loop_count > 3) { + // Scan previous 6 bytes + if (IsMips16 | IsMicromips) + loop_count = 3; + // For mips-only, instructions are always 4 bytes, so scan previous 4 + // bytes only. + else + loop_count = 2; + } + + // Create Disassembler Instance + lldb::DisassemblerSP disasm_sp( + Disassembler::FindPlugin(m_arch, nullptr, nullptr)); + + InstructionList instruction_list; + InstructionSP prev_insn; + bool prefer_file_cache = true; // Read from file + uint32_t inst_to_choose = 0; + + Address addr = resolved_addr; + + for (uint32_t i = 1; i <= loop_count; i++) { + // Adjust the address to read from. + addr.Slide(-2); + AddressRange range(addr, i * 2); + uint32_t insn_size = 0; + + disasm_sp->ParseInstructions(&exe_ctx, range, nullptr, prefer_file_cache); + + uint32_t num_insns = disasm_sp->GetInstructionList().GetSize(); + if (num_insns) { + prev_insn = disasm_sp->GetInstructionList().GetInstructionAtIndex(0); + insn_size = prev_insn->GetOpcode().GetByteSize(); + if (i == 1 && insn_size == 2) { + // This looks like a valid 2-byte instruction (but it could be a part + // of upper 4 byte instruction). + instruction_list.Append(prev_insn); + inst_to_choose = 1; + } + else if (i == 2) { + // Here we may get one 4-byte instruction or two 2-byte instructions. + if (num_insns == 2) { + // Looks like there are two 2-byte instructions above our + // breakpoint target address. Now the upper 2-byte instruction is + // either a valid 2-byte instruction or could be a part of it's + // upper 4-byte instruction. In both cases we don't care because in + // this case lower 2-byte instruction is definitely a valid + // instruction and whatever i=1 iteration has found out is true. + inst_to_choose = 1; + break; + } + else if (insn_size == 4) { + // This instruction claims its a valid 4-byte instruction. But it + // could be a part of it's upper 4-byte instruction. Lets try + // scanning upper 2 bytes to verify this. + instruction_list.Append(prev_insn); + inst_to_choose = 2; + } + } + else if (i == 3) { + if (insn_size == 4) + // FIXME: We reached here that means instruction at [target - 4] has + // already claimed to be a 4-byte instruction, and now instruction + // at [target - 6] is also claiming that it's a 4-byte instruction. + // This can not be true. In this case we can not decide the valid + // previous instruction so we let lldb set the breakpoint at the + // address given by user. + inst_to_choose = 0; + else + // This is straight-forward + inst_to_choose = 2; + break; + } + } + else { + // Decode failed, bytes do not form a valid instruction. So whatever + // previous iteration has found out is true. + if (i > 1) { + inst_to_choose = i - 1; + break; + } + } + } + + // Check if we are able to find any valid instruction. + if (inst_to_choose) { + if (inst_to_choose > instruction_list.GetSize()) + inst_to_choose--; + return instruction_list.GetInstructionAtIndex(inst_to_choose - 1).get(); + } + + return nullptr; +} |