Author: sas Date: Fri Sep 22 16:41:41 2017 New Revision: 314045 URL: http://llvm.org/viewvc/llvm-project?rev=314045&view=rev Log: Implement trampoline step-through for Windows-x86.
Summary: This is required to be able to step through calls to external functions that are not properly marked with __declspec(dllimport). When a call like this is emitted, the linker will inject a trampoline to produce an indirect call through the IAT. Reviewers: zturner, jingham Reviewed By: jingham Subscribers: sas, jingham, lldb-commits Differential Revision: https://reviews.llvm.org/D22231 Modified: lldb/trunk/source/Plugins/DynamicLoader/Windows-DYLD/DynamicLoaderWindowsDYLD.cpp Modified: lldb/trunk/source/Plugins/DynamicLoader/Windows-DYLD/DynamicLoaderWindowsDYLD.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/DynamicLoader/Windows-DYLD/DynamicLoaderWindowsDYLD.cpp?rev=314045&r1=314044&r2=314045&view=diff ============================================================================== --- lldb/trunk/source/Plugins/DynamicLoader/Windows-DYLD/DynamicLoaderWindowsDYLD.cpp (original) +++ lldb/trunk/source/Plugins/DynamicLoader/Windows-DYLD/DynamicLoaderWindowsDYLD.cpp Fri Sep 22 16:41:41 2017 @@ -11,8 +11,11 @@ #include "DynamicLoaderWindowsDYLD.h" #include "lldb/Core/PluginManager.h" +#include "lldb/Target/ExecutionContext.h" #include "lldb/Target/Process.h" +#include "lldb/Target/RegisterContext.h" #include "lldb/Target/Target.h" +#include "lldb/Target/ThreadPlanStepInstruction.h" #include "llvm/ADT/Triple.h" @@ -72,5 +75,44 @@ uint32_t DynamicLoaderWindowsDYLD::GetPl ThreadPlanSP DynamicLoaderWindowsDYLD::GetStepThroughTrampolinePlan(Thread &thread, bool stop) { - return ThreadPlanSP(); + auto arch = m_process->GetTarget().GetArchitecture(); + if (arch.GetMachine() != llvm::Triple::x86) { + return ThreadPlanSP(); + } + + uint64_t pc = thread.GetRegisterContext()->GetPC(); + // Max size of an instruction in x86 is 15 bytes. + AddressRange range(pc, 2 * 15); + + ExecutionContext exe_ctx(m_process->GetTarget()); + DisassemblerSP disassembler_sp = Disassembler::DisassembleRange( + arch, nullptr, nullptr, exe_ctx, range, true); + if (!disassembler_sp) { + return ThreadPlanSP(); + } + + InstructionList *insn_list = &disassembler_sp->GetInstructionList(); + if (insn_list == nullptr) { + return ThreadPlanSP(); + } + + // First instruction in a x86 Windows trampoline is going to be an indirect + // jump through the IAT and the next one will be a nop (usually there for + // alignment purposes). e.g.: + // 0x70ff4cfc <+956>: jmpl *0x7100c2a8 + // 0x70ff4d02 <+962>: nop + + auto first_insn = insn_list->GetInstructionAtIndex(0); + auto second_insn = insn_list->GetInstructionAtIndex(1); + + if (first_insn == nullptr || second_insn == nullptr || + strcmp(first_insn->GetMnemonic(&exe_ctx), "jmpl") != 0 || + strcmp(second_insn->GetMnemonic(&exe_ctx), "nop") != 0) { + return ThreadPlanSP(); + } + + assert(first_insn->DoesBranch() && !second_insn->DoesBranch()); + + return ThreadPlanSP(new ThreadPlanStepInstruction( + thread, false, false, eVoteNoOpinion, eVoteNoOpinion)); } _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
