Not yet enabled as the default unwinder but there are no known backtrace problems with the code at this point. Added 'log enable lldb unwind' to help diagnose backtrace problems; this output needs a little refining but it's a good first step. eh_frame information is currently read unconditionally - the code is structured to allow this to be delayed until it's actually needed. There is a performance hit when you have to parse the eh_frame information for any largeish executable/library so it's necessary to avoid if possible. It's confusing having both the UnwindPlan::RegisterLocation struct and the RegisterConextLLDB::RegisterLocation struct, I need to rename one of them. The writing of registers isn't done in the RegisterConextLLDB subclass yet; neither is the running of complex DWARF expressions from eh_frame (e.g. used for _sigtramp on Mac OS X). llvm-svn: 117256
142 lines
4.5 KiB
C++
142 lines
4.5 KiB
C++
//===-- UnwindLLDB.cpp -------------------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "lldb/Target/Thread.h"
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#include "lldb/Target/Target.h"
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#include "lldb/Target/Process.h"
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#include "lldb/Target/RegisterContext.h"
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#include "lldb/Core/Module.h"
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#include "lldb/Symbol/FuncUnwinders.h"
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#include "lldb/Symbol/Function.h"
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#include "lldb/Utility/ArchDefaultUnwindPlan.h"
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#include "UnwindLLDB.h"
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#include "lldb/Symbol/UnwindPlan.h"
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#include "lldb/Core/Log.h"
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using namespace lldb;
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using namespace lldb_private;
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UnwindLLDB::UnwindLLDB (Thread &thread) :
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Unwind (thread),
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m_frames()
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{
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}
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uint32_t
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UnwindLLDB::GetFrameCount()
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{
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Log *log = GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND);
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if (m_frames.empty())
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{
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// First, set up the 0th (initial) frame
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Cursor first_cursor;
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RegisterContextSP no_frame; // an empty shared pointer
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RegisterContextLLDB *first_register_ctx = new RegisterContextLLDB(m_thread, no_frame, first_cursor.sctx, 0);
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if (!first_register_ctx->IsValid())
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{
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delete first_register_ctx;
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return 0;
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}
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if (!first_register_ctx->GetCFA (first_cursor.cfa))
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{
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delete first_register_ctx;
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return 0;
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}
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if (!first_register_ctx->GetPC (first_cursor.start_pc))
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{
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delete first_register_ctx;
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return 0;
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}
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// Reuse the StackFrame provided by the processor native machine context for the first frame
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first_register_ctx->SetStackFrame (m_thread.GetStackFrameAtIndex(0).get());
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RegisterContextSP temp_rcs(first_register_ctx);
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first_cursor.reg_ctx = temp_rcs;
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m_frames.push_back (first_cursor);
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// Now walk up the rest of the stack
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while (1)
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{
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Cursor cursor;
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RegisterContextLLDB *register_ctx;
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int cur_idx = m_frames.size ();
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register_ctx = new RegisterContextLLDB (m_thread, m_frames[cur_idx - 1].reg_ctx, cursor.sctx, cur_idx);
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if (!register_ctx->IsValid())
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{
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delete register_ctx;
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if (log)
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{
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log->Printf("%*sThread %u Frame %d invalid RegisterContext for this frame, stopping stack walk",
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cur_idx, "", m_thread.GetIndexID(), cur_idx);
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}
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break;
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}
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if (!register_ctx->GetCFA (cursor.cfa))
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{
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delete register_ctx;
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if (log)
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{
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log->Printf("%*sThread %u Frame %d did not get CFA for this frame, stopping stack walk",
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cur_idx, "", m_thread.GetIndexID(), cur_idx);
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}
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break;
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}
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if (!register_ctx->GetPC (cursor.start_pc))
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{
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delete register_ctx;
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if (log)
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{
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log->Printf("%*sThread %u Frame %d did not get PC for this frame, stopping stack walk",
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cur_idx, "", m_thread.GetIndexID(), cur_idx);
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}
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break;
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}
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RegisterContextSP temp_rcs(register_ctx);
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StackFrame *frame = new StackFrame(cur_idx, cur_idx, m_thread, temp_rcs, cursor.cfa, cursor.start_pc, &cursor.sctx);
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register_ctx->SetStackFrame (frame);
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cursor.reg_ctx = temp_rcs;
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m_frames.push_back (cursor);
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}
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}
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return m_frames.size ();
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}
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bool
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UnwindLLDB::GetFrameInfoAtIndex (uint32_t idx, addr_t& cfa, addr_t& pc)
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{
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// FIXME don't get the entire stack if it isn't needed.
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if (m_frames.size() == 0)
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GetFrameCount();
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if (idx < m_frames.size ())
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{
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cfa = m_frames[idx].cfa;
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pc = m_frames[idx].start_pc;
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return true;
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}
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return false;
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}
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RegisterContext *
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UnwindLLDB::CreateRegisterContextForFrame (StackFrame *frame)
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{
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uint32_t idx = frame->GetFrameIndex ();
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// FIXME don't get the entire stack if it isn't needed.
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if (m_frames.size() == 0)
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GetFrameCount();
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if (idx == 0)
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{
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return m_thread.GetRegisterContext();
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}
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if (idx < m_frames.size ())
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return m_frames[idx].reg_ctx.get();
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return NULL;
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}
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