Import LLVM 10.0.0 release including clang, lld and lldb.

ok hackroom
tested by plenty

1 files changed, 519 insertions, 0 deletions

diff --git a/gnu/llvm/lldb/source/Plugins/Process/Utility/UnwindLLDB.cpp b/gnu/llvm/lldb/source/Plugins/Process/Utility/UnwindLLDB.cpp
new file mode 100644
index 00000000000..74fc90e8854
--- /dev/null
+++ b/gnu/llvm/lldb/source/Plugins/Process/Utility/UnwindLLDB.cpp
@@ -0,0 +1,519 @@
+//===-- UnwindLLDB.cpp -------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Core/Module.h"
+#include "lldb/Symbol/FuncUnwinders.h"
+#include "lldb/Symbol/Function.h"
+#include "lldb/Symbol/UnwindPlan.h"
+#include "lldb/Target/ABI.h"
+#include "lldb/Target/Process.h"
+#include "lldb/Target/RegisterContext.h"
+#include "lldb/Target/Target.h"
+#include "lldb/Target/Thread.h"
+#include "lldb/Utility/Log.h"
+
+#include "RegisterContextLLDB.h"
+#include "UnwindLLDB.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+UnwindLLDB::UnwindLLDB(Thread &thread)
+    : Unwind(thread), m_frames(), m_unwind_complete(false),
+      m_user_supplied_trap_handler_functions() {
+  ProcessSP process_sp(thread.GetProcess());
+  if (process_sp) {
+    Args args;
+    process_sp->GetTarget().GetUserSpecifiedTrapHandlerNames(args);
+    size_t count = args.GetArgumentCount();
+    for (size_t i = 0; i < count; i++) {
+      const char *func_name = args.GetArgumentAtIndex(i);
+      m_user_supplied_trap_handler_functions.push_back(ConstString(func_name));
+    }
+  }
+}
+
+uint32_t UnwindLLDB::DoGetFrameCount() {
+  if (!m_unwind_complete) {
+//#define DEBUG_FRAME_SPEED 1
+#if DEBUG_FRAME_SPEED
+#define FRAME_COUNT 10000
+    using namespace std::chrono;
+    auto time_value = steady_clock::now();
+#endif
+    if (!AddFirstFrame())
+      return 0;
+
+    ProcessSP process_sp(m_thread.GetProcess());
+    ABI *abi = process_sp ? process_sp->GetABI().get() : nullptr;
+
+    while (AddOneMoreFrame(abi)) {
+#if DEBUG_FRAME_SPEED
+      if ((m_frames.size() % FRAME_COUNT) == 0) {
+        const auto now = steady_clock::now();
+        const auto delta_t = now - time_value;
+        printf("%u frames in %.9f ms (%g frames/sec)\n", FRAME_COUNT,
+               duration<double, std::milli>(delta_t).count(),
+               (float)FRAME_COUNT / duration<double>(delta_t).count());
+        time_value = now;
+      }
+#endif
+    }
+  }
+  return m_frames.size();
+}
+
+bool UnwindLLDB::AddFirstFrame() {
+  if (m_frames.size() > 0)
+    return true;
+
+  ProcessSP process_sp(m_thread.GetProcess());
+  ABI *abi = process_sp ? process_sp->GetABI().get() : nullptr;
+
+  // First, set up the 0th (initial) frame
+  CursorSP first_cursor_sp(new Cursor());
+  RegisterContextLLDBSP reg_ctx_sp(new RegisterContextLLDB(
+      m_thread, RegisterContextLLDBSP(), first_cursor_sp->sctx, 0, *this));
+  if (reg_ctx_sp.get() == nullptr)
+    goto unwind_done;
+
+  if (!reg_ctx_sp->IsValid())
+    goto unwind_done;
+
+  if (!reg_ctx_sp->GetCFA(first_cursor_sp->cfa))
+    goto unwind_done;
+
+  if (!reg_ctx_sp->ReadPC(first_cursor_sp->start_pc))
+    goto unwind_done;
+
+  // Everything checks out, so release the auto pointer value and let the
+  // cursor own it in its shared pointer
+  first_cursor_sp->reg_ctx_lldb_sp = reg_ctx_sp;
+  m_frames.push_back(first_cursor_sp);
+
+  // Update the Full Unwind Plan for this frame if not valid
+  UpdateUnwindPlanForFirstFrameIfInvalid(abi);
+
+  return true;
+
+unwind_done:
+  Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND));
+  if (log) {
+    LLDB_LOGF(log, "th%d Unwind of this thread is complete.",
+              m_thread.GetIndexID());
+  }
+  m_unwind_complete = true;
+  return false;
+}
+
+UnwindLLDB::CursorSP UnwindLLDB::GetOneMoreFrame(ABI *abi) {
+  assert(m_frames.size() != 0 &&
+         "Get one more frame called with empty frame list");
+
+  // If we've already gotten to the end of the stack, don't bother to try
+  // again...
+  if (m_unwind_complete)
+    return nullptr;
+
+  Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND));
+
+  CursorSP prev_frame = m_frames.back();
+  uint32_t cur_idx = m_frames.size();
+
+  CursorSP cursor_sp(new Cursor());
+  RegisterContextLLDBSP reg_ctx_sp(new RegisterContextLLDB(
+      m_thread, prev_frame->reg_ctx_lldb_sp, cursor_sp->sctx, cur_idx, *this));
+
+  uint64_t max_stack_depth = m_thread.GetMaxBacktraceDepth();
+
+  // We want to detect an unwind that cycles erroneously and stop backtracing.
+  // Don't want this maximum unwind limit to be too low -- if you have a
+  // backtrace with an "infinitely recursing" bug, it will crash when the stack
+  // blows out and the first 35,000 frames are uninteresting - it's the top
+  // most 5 frames that you actually care about.  So you can't just cap the
+  // unwind at 10,000 or something. Realistically anything over around 200,000
+  // is going to blow out the stack space. If we're still unwinding at that
+  // point, we're probably never going to finish.
+  if (cur_idx >= max_stack_depth) {
+    LLDB_LOGF(log,
+              "%*sFrame %d unwound too many frames, assuming unwind has "
+              "gone astray, stopping.",
+              cur_idx < 100 ? cur_idx : 100, "", cur_idx);
+    return nullptr;
+  }
+
+  if (reg_ctx_sp.get() == nullptr) {
+    // If the RegisterContextLLDB has a fallback UnwindPlan, it will switch to
+    // that and return true.  Subsequent calls to TryFallbackUnwindPlan() will
+    // return false.
+    if (prev_frame->reg_ctx_lldb_sp->TryFallbackUnwindPlan()) {
+      // TryFallbackUnwindPlan for prev_frame succeeded and updated
+      // reg_ctx_lldb_sp field of prev_frame. However, cfa field of prev_frame
+      // still needs to be updated. Hence updating it.
+      if (!(prev_frame->reg_ctx_lldb_sp->GetCFA(prev_frame->cfa)))
+        return nullptr;
+
+      return GetOneMoreFrame(abi);
+    }
+
+    LLDB_LOGF(log, "%*sFrame %d did not get a RegisterContext, stopping.",
+              cur_idx < 100 ? cur_idx : 100, "", cur_idx);
+    return nullptr;
+  }
+
+  if (!reg_ctx_sp->IsValid()) {
+    // We failed to get a valid RegisterContext. See if the regctx below this
+    // on the stack has a fallback unwind plan it can use. Subsequent calls to
+    // TryFallbackUnwindPlan() will return false.
+    if (prev_frame->reg_ctx_lldb_sp->TryFallbackUnwindPlan()) {
+      // TryFallbackUnwindPlan for prev_frame succeeded and updated
+      // reg_ctx_lldb_sp field of prev_frame. However, cfa field of prev_frame
+      // still needs to be updated. Hence updating it.
+      if (!(prev_frame->reg_ctx_lldb_sp->GetCFA(prev_frame->cfa)))
+        return nullptr;
+
+      return GetOneMoreFrame(abi);
+    }
+
+    LLDB_LOGF(log,
+              "%*sFrame %d invalid RegisterContext for this frame, "
+              "stopping stack walk",
+              cur_idx < 100 ? cur_idx : 100, "", cur_idx);
+    return nullptr;
+  }
+  if (!reg_ctx_sp->GetCFA(cursor_sp->cfa)) {
+    // If the RegisterContextLLDB has a fallback UnwindPlan, it will switch to
+    // that and return true.  Subsequent calls to TryFallbackUnwindPlan() will
+    // return false.
+    if (prev_frame->reg_ctx_lldb_sp->TryFallbackUnwindPlan()) {
+      // TryFallbackUnwindPlan for prev_frame succeeded and updated
+      // reg_ctx_lldb_sp field of prev_frame. However, cfa field of prev_frame
+      // still needs to be updated. Hence updating it.
+      if (!(prev_frame->reg_ctx_lldb_sp->GetCFA(prev_frame->cfa)))
+        return nullptr;
+
+      return GetOneMoreFrame(abi);
+    }
+
+    LLDB_LOGF(log,
+              "%*sFrame %d did not get CFA for this frame, stopping stack walk",
+              cur_idx < 100 ? cur_idx : 100, "", cur_idx);
+    return nullptr;
+  }
+  if (abi && !abi->CallFrameAddressIsValid(cursor_sp->cfa)) {
+    // On Mac OS X, the _sigtramp asynchronous signal trampoline frame may not
+    // have its (constructed) CFA aligned correctly -- don't do the abi
+    // alignment check for these.
+    if (!reg_ctx_sp->IsTrapHandlerFrame()) {
+      // See if we can find a fallback unwind plan for THIS frame.  It may be
+      // that the UnwindPlan we're using for THIS frame was bad and gave us a
+      // bad CFA. If that's not it, then see if we can change the UnwindPlan
+      // for the frame below us ("NEXT") -- see if using that other UnwindPlan
+      // gets us a better unwind state.
+      if (!reg_ctx_sp->TryFallbackUnwindPlan() ||
+          !reg_ctx_sp->GetCFA(cursor_sp->cfa) ||
+          !abi->CallFrameAddressIsValid(cursor_sp->cfa)) {
+        if (prev_frame->reg_ctx_lldb_sp->TryFallbackUnwindPlan()) {
+          // TryFallbackUnwindPlan for prev_frame succeeded and updated
+          // reg_ctx_lldb_sp field of prev_frame. However, cfa field of
+          // prev_frame still needs to be updated. Hence updating it.
+          if (!(prev_frame->reg_ctx_lldb_sp->GetCFA(prev_frame->cfa)))
+            return nullptr;
+
+          return GetOneMoreFrame(abi);
+        }
+
+        LLDB_LOGF(log,
+                  "%*sFrame %d did not get a valid CFA for this frame, "
+                  "stopping stack walk",
+                  cur_idx < 100 ? cur_idx : 100, "", cur_idx);
+        return nullptr;
+      } else {
+        LLDB_LOGF(log,
+                  "%*sFrame %d had a bad CFA value but we switched the "
+                  "UnwindPlan being used and got one that looks more "
+                  "realistic.",
+                  cur_idx < 100 ? cur_idx : 100, "", cur_idx);
+      }
+    }
+  }
+  if (!reg_ctx_sp->ReadPC(cursor_sp->start_pc)) {
+    // If the RegisterContextLLDB has a fallback UnwindPlan, it will switch to
+    // that and return true.  Subsequent calls to TryFallbackUnwindPlan() will
+    // return false.
+    if (prev_frame->reg_ctx_lldb_sp->TryFallbackUnwindPlan()) {
+      // TryFallbackUnwindPlan for prev_frame succeeded and updated
+      // reg_ctx_lldb_sp field of prev_frame. However, cfa field of prev_frame
+      // still needs to be updated. Hence updating it.
+      if (!(prev_frame->reg_ctx_lldb_sp->GetCFA(prev_frame->cfa)))
+        return nullptr;
+
+      return GetOneMoreFrame(abi);
+    }
+
+    LLDB_LOGF(log,
+              "%*sFrame %d did not get PC for this frame, stopping stack walk",
+              cur_idx < 100 ? cur_idx : 100, "", cur_idx);
+    return nullptr;
+  }
+  if (abi && !abi->CodeAddressIsValid(cursor_sp->start_pc)) {
+    // If the RegisterContextLLDB has a fallback UnwindPlan, it will switch to
+    // that and return true.  Subsequent calls to TryFallbackUnwindPlan() will
+    // return false.
+    if (prev_frame->reg_ctx_lldb_sp->TryFallbackUnwindPlan()) {
+      // TryFallbackUnwindPlan for prev_frame succeeded and updated
+      // reg_ctx_lldb_sp field of prev_frame. However, cfa field of prev_frame
+      // still needs to be updated. Hence updating it.
+      if (!(prev_frame->reg_ctx_lldb_sp->GetCFA(prev_frame->cfa)))
+        return nullptr;
+
+      return GetOneMoreFrame(abi);
+    }
+
+    LLDB_LOGF(log, "%*sFrame %d did not get a valid PC, stopping stack walk",
+              cur_idx < 100 ? cur_idx : 100, "", cur_idx);
+    return nullptr;
+  }
+  // Infinite loop where the current cursor is the same as the previous one...
+  if (prev_frame->start_pc == cursor_sp->start_pc &&
+      prev_frame->cfa == cursor_sp->cfa) {
+    LLDB_LOGF(log,
+              "th%d pc of this frame is the same as the previous frame and "
+              "CFAs for both frames are identical -- stopping unwind",
+              m_thread.GetIndexID());
+    return nullptr;
+  }
+
+  cursor_sp->reg_ctx_lldb_sp = reg_ctx_sp;
+  return cursor_sp;
+}
+
+void UnwindLLDB::UpdateUnwindPlanForFirstFrameIfInvalid(ABI *abi) {
+  // This function is called for First Frame only.
+  assert(m_frames.size() == 1 && "No. of cursor frames are not 1");
+
+  bool old_m_unwind_complete = m_unwind_complete;
+  CursorSP old_m_candidate_frame = m_candidate_frame;
+
+  // Try to unwind 2 more frames using the Unwinder. It uses Full UnwindPlan
+  // and if Full UnwindPlan fails, then uses FallBack UnwindPlan. Also update
+  // the cfa of Frame 0 (if required).
+  AddOneMoreFrame(abi);
+
+  // Remove all the frames added by above function as the purpose of using
+  // above function was just to check whether Unwinder of Frame 0 works or not.
+  for (uint32_t i = 1; i < m_frames.size(); i++)
+    m_frames.pop_back();
+
+  // Restore status after calling AddOneMoreFrame
+  m_unwind_complete = old_m_unwind_complete;
+  m_candidate_frame = old_m_candidate_frame;
+  return;
+}
+
+bool UnwindLLDB::AddOneMoreFrame(ABI *abi) {
+  Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND));
+
+  // Frame zero is a little different
+  if (m_frames.empty())
+    return false;
+
+  // If we've already gotten to the end of the stack, don't bother to try
+  // again...
+  if (m_unwind_complete)
+    return false;
+
+  CursorSP new_frame = m_candidate_frame;
+  if (new_frame == nullptr)
+    new_frame = GetOneMoreFrame(abi);
+
+  if (new_frame == nullptr) {
+    LLDB_LOGF(log, "th%d Unwind of this thread is complete.",
+              m_thread.GetIndexID());
+    m_unwind_complete = true;
+    return false;
+  }
+
+  m_frames.push_back(new_frame);
+
+  // If we can get one more frame further then accept that we get back a
+  // correct frame.
+  m_candidate_frame = GetOneMoreFrame(abi);
+  if (m_candidate_frame)
+    return true;
+
+  // We can't go further from the frame returned by GetOneMore frame. Lets try
+  // to get a different frame with using the fallback unwind plan.
+  if (!m_frames[m_frames.size() - 2]
+           ->reg_ctx_lldb_sp->TryFallbackUnwindPlan()) {
+    // We don't have a valid fallback unwind plan. Accept the frame as it is.
+    // This is a valid situation when we are at the bottom of the stack.
+    return true;
+  }
+
+  // Remove the possibly incorrect frame from the frame list and try to add a
+  // different one with the newly selected fallback unwind plan.
+  m_frames.pop_back();
+  CursorSP new_frame_v2 = GetOneMoreFrame(abi);
+  if (new_frame_v2 == nullptr) {
+    // We haven't got a new frame from the fallback unwind plan. Accept the
+    // frame from the original unwind plan. This is a valid situation when we
+    // are at the bottom of the stack.
+    m_frames.push_back(new_frame);
+    return true;
+  }
+
+  // Push the new frame to the list and try to continue from this frame. If we
+  // can get a new frame then accept it as the correct one.
+  m_frames.push_back(new_frame_v2);
+  m_candidate_frame = GetOneMoreFrame(abi);
+  if (m_candidate_frame) {
+    // If control reached here then TryFallbackUnwindPlan had succeeded for
+    // Cursor::m_frames[m_frames.size() - 2]. It also succeeded to Unwind next
+    // 2 frames i.e. m_frames[m_frames.size() - 1] and a frame after that. For
+    // Cursor::m_frames[m_frames.size() - 2], reg_ctx_lldb_sp field was already
+    // updated during TryFallbackUnwindPlan call above. However, cfa field
+    // still needs to be updated. Hence updating it here and then returning.
+    return m_frames[m_frames.size() - 2]->reg_ctx_lldb_sp->GetCFA(
+        m_frames[m_frames.size() - 2]->cfa);
+  }
+
+  // The new frame hasn't helped in unwinding. Fall back to the original one as
+  // the default unwind plan is usually more reliable then the fallback one.
+  m_frames.pop_back();
+  m_frames.push_back(new_frame);
+  return true;
+}
+
+bool UnwindLLDB::DoGetFrameInfoAtIndex(uint32_t idx, addr_t &cfa, addr_t &pc,
+                                       bool &behaves_like_zeroth_frame) {
+  if (m_frames.size() == 0) {
+    if (!AddFirstFrame())
+      return false;
+  }
+
+  ProcessSP process_sp(m_thread.GetProcess());
+  ABI *abi = process_sp ? process_sp->GetABI().get() : nullptr;
+
+  while (idx >= m_frames.size() && AddOneMoreFrame(abi))
+    ;
+
+  if (idx < m_frames.size()) {
+    cfa = m_frames[idx]->cfa;
+    pc = m_frames[idx]->start_pc;
+    if (idx == 0) {
+      // Frame zero always behaves like it.
+      behaves_like_zeroth_frame = true;
+    } else if (m_frames[idx - 1]->reg_ctx_lldb_sp->IsTrapHandlerFrame()) {
+      // This could be an asynchronous signal, thus the
+      // pc might point to the interrupted instruction rather
+      // than a post-call instruction
+      behaves_like_zeroth_frame = true;
+    } else if (m_frames[idx]->reg_ctx_lldb_sp->IsTrapHandlerFrame()) {
+      // This frame may result from signal processing installing
+      // a pointer to the first byte of a signal-return trampoline
+      // in the return address slot of the frame below, so this
+      // too behaves like the zeroth frame (i.e. the pc might not
+      // be pointing just past a call in it)
+      behaves_like_zeroth_frame = true;
+    } else {
+      behaves_like_zeroth_frame = false;
+    }
+    return true;
+  }
+  return false;
+}
+
+lldb::RegisterContextSP
+UnwindLLDB::DoCreateRegisterContextForFrame(StackFrame *frame) {
+  lldb::RegisterContextSP reg_ctx_sp;
+  uint32_t idx = frame->GetConcreteFrameIndex();
+
+  if (idx == 0) {
+    return m_thread.GetRegisterContext();
+  }
+
+  if (m_frames.size() == 0) {
+    if (!AddFirstFrame())
+      return reg_ctx_sp;
+  }
+
+  ProcessSP process_sp(m_thread.GetProcess());
+  ABI *abi = process_sp ? process_sp->GetABI().get() : nullptr;
+
+  while (idx >= m_frames.size()) {
+    if (!AddOneMoreFrame(abi))
+      break;
+  }
+
+  const uint32_t num_frames = m_frames.size();
+  if (idx < num_frames) {
+    Cursor *frame_cursor = m_frames[idx].get();
+    reg_ctx_sp = frame_cursor->reg_ctx_lldb_sp;
+  }
+  return reg_ctx_sp;
+}
+
+UnwindLLDB::RegisterContextLLDBSP
+UnwindLLDB::GetRegisterContextForFrameNum(uint32_t frame_num) {
+  RegisterContextLLDBSP reg_ctx_sp;
+  if (frame_num < m_frames.size())
+    reg_ctx_sp = m_frames[frame_num]->reg_ctx_lldb_sp;
+  return reg_ctx_sp;
+}
+
+bool UnwindLLDB::SearchForSavedLocationForRegister(
+    uint32_t lldb_regnum, lldb_private::UnwindLLDB::RegisterLocation &regloc,
+    uint32_t starting_frame_num, bool pc_reg) {
+  int64_t frame_num = starting_frame_num;
+  if (static_cast<size_t>(frame_num) >= m_frames.size())
+    return false;
+
+  // Never interrogate more than one level while looking for the saved pc
+  // value. If the value isn't saved by frame_num, none of the frames lower on
+  // the stack will have a useful value.
+  if (pc_reg) {
+    UnwindLLDB::RegisterSearchResult result;
+    result = m_frames[frame_num]->reg_ctx_lldb_sp->SavedLocationForRegister(
+        lldb_regnum, regloc);
+    return result == UnwindLLDB::RegisterSearchResult::eRegisterFound;
+  }
+  while (frame_num >= 0) {
+    UnwindLLDB::RegisterSearchResult result;
+    result = m_frames[frame_num]->reg_ctx_lldb_sp->SavedLocationForRegister(
+        lldb_regnum, regloc);
+
+    // We descended down to the live register context aka stack frame 0 and are
+    // reading the value out of a live register.
+    if (result == UnwindLLDB::RegisterSearchResult::eRegisterFound &&
+        regloc.type ==
+            UnwindLLDB::RegisterLocation::eRegisterInLiveRegisterContext) {
+      return true;
+    }
+
+    // If we have unwind instructions saying that register N is saved in
+    // register M in the middle of the stack (and N can equal M here, meaning
+    // the register was not used in this function), then change the register
+    // number we're looking for to M and keep looking for a concrete  location
+    // down the stack, or an actual value from a live RegisterContext at frame
+    // 0.
+    if (result == UnwindLLDB::RegisterSearchResult::eRegisterFound &&
+        regloc.type == UnwindLLDB::RegisterLocation::eRegisterInRegister &&
+        frame_num > 0) {
+      result = UnwindLLDB::RegisterSearchResult::eRegisterNotFound;
+      lldb_regnum = regloc.location.register_number;
+    }
+
+    if (result == UnwindLLDB::RegisterSearchResult::eRegisterFound)
+      return true;
+    if (result == UnwindLLDB::RegisterSearchResult::eRegisterIsVolatile)
+      return false;
+    frame_num--;
+  }
+  return false;
+}