mc: move some files related to ELF, DWARF or unwind reading into their own directory

[simgrid.git] / src / mc / inspect / LocationList.cpp

diff --git a/src/mc/inspect/LocationList.cpp b/src/mc/inspect/LocationList.cpp
new file mode 100644 (file)
index 0000000..500b851
--- /dev/null
+++ b/src/mc/inspect/LocationList.cpp
@@ -0,0 +1,101 @@
+/* Copyright (c) 2004-2019. The SimGrid Team. All rights reserved.          */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+#include <cstddef>
+#include <cstdint>
+#include <utility>
+
+#include "xbt/asserts.h"
+#include "xbt/sysdep.h"
+
+#include <libunwind.h>
+
+#include "src/mc/LocationList.hpp"
+#include "src/mc/ObjectInformation.hpp"
+#include "src/mc/mc_dwarf.hpp"
+
+namespace simgrid {
+namespace dwarf {
+
+/** Resolve a location expression */
+Location resolve(simgrid::dwarf::DwarfExpression const& expression, simgrid::mc::ObjectInformation* object_info,
+                 unw_cursor_t* c, void* frame_pointer_address, simgrid::mc::AddressSpace* address_space,
+                 int process_index)
+{
+  simgrid::dwarf::ExpressionContext context;
+  context.frame_base    = frame_pointer_address;
+  context.cursor        = c;
+  context.address_space = address_space;
+  context.object_info   = object_info;
+  context.process_index = process_index;
+
+  if (not expression.empty() && expression[0].atom >= DW_OP_reg0 && expression[0].atom <= DW_OP_reg31) {
+    int dwarf_register = expression[0].atom - DW_OP_reg0;
+    xbt_assert(c, "Missing frame context for register operation DW_OP_reg%i", dwarf_register);
+    return Location(dwarf_register_to_libunwind(dwarf_register));
+  }
+
+  simgrid::dwarf::ExpressionStack stack;
+  simgrid::dwarf::execute(expression, context, stack);
+  return Location((void*)stack.top());
+}
+
+// TODO, move this in a method of LocationList
+static simgrid::dwarf::DwarfExpression const* find_expression(simgrid::dwarf::LocationList const& locations,
+                                                              unw_word_t ip)
+{
+  for (simgrid::dwarf::LocationListEntry const& entry : locations)
+    if (entry.valid_for_ip(ip))
+      return &entry.expression();
+  return nullptr;
+}
+
+Location resolve(simgrid::dwarf::LocationList const& locations, simgrid::mc::ObjectInformation* object_info,
+                 unw_cursor_t* c, void* frame_pointer_address, simgrid::mc::AddressSpace* address_space,
+                 int process_index)
+{
+  unw_word_t ip = 0;
+  if (c && unw_get_reg(c, UNW_REG_IP, &ip))
+    xbt_die("Could not resolve IP");
+  simgrid::dwarf::DwarfExpression const* expression = find_expression(locations, ip);
+  if (not expression)
+    xbt_die("Could not resolve location");
+  return simgrid::dwarf::resolve(*expression, object_info, c, frame_pointer_address, address_space, process_index);
+}
+
+LocationList location_list(simgrid::mc::ObjectInformation& info, Dwarf_Attribute& attr)
+{
+  LocationList locations;
+  std::ptrdiff_t offset = 0;
+  while (1) {
+    Dwarf_Addr base;
+    Dwarf_Addr start;
+    Dwarf_Addr end;
+    Dwarf_Op* ops;
+    std::size_t len;
+
+    offset = dwarf_getlocations(&attr, offset, &base, &start, &end, &ops, &len);
+
+    if (offset == 0)
+      break;
+    else if (offset == -1)
+      xbt_die("Error while loading location list");
+
+    std::uint64_t base_address = (std::uint64_t)info.base_address();
+
+    LocationListEntry::range_type range;
+    if (start == 0)
+      // If start == 0, this is not a location list:
+      range = {0, UINT64_MAX};
+    else
+      range = {base_address + start, base_address + end};
+
+    locations.push_back({DwarfExpression(ops, ops + len), range});
+  }
+
+  return locations;
+}
+} // namespace dwarf
+} // namespace simgrid