X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/196b543c8e909828b40e851eaf4443ee28f76c70..HEAD:/src/mc/inspect/mc_dwarf.cpp?ds=sidebyside diff --git a/src/mc/inspect/mc_dwarf.cpp b/src/mc/inspect/mc_dwarf.cpp deleted file mode 100644 index 553ec19cf6..0000000000 --- a/src/mc/inspect/mc_dwarf.cpp +++ /dev/null @@ -1,1209 +0,0 @@ -/* Copyright (c) 2008-2022. 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 "src/simgrid/util.hpp" -#include "xbt/log.h" -#include "xbt/string.hpp" -#include "xbt/sysdep.h" -#include - -#include "src/mc/inspect/ObjectInformation.hpp" -#include "src/mc/inspect/Variable.hpp" -#include "src/mc/inspect/mc_dwarf.hpp" -#include "src/mc/mc_private.hpp" -#include "src/mc/remote/RemoteProcess.hpp" - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include - -#include -#include - -XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_dwarf, mc, "DWARF processing"); - -/** @brief The default DW_TAG_lower_bound for a given DW_AT_language. - * - * The default for a given language is defined in the DWARF spec. - * - * @param language constant as defined by the DWARf spec - */ -static uint64_t MC_dwarf_default_lower_bound(int lang); - -/** @brief Computes the the element_count of a DW_TAG_enumeration_type DIE - * - * This is the number of elements in a given array dimension. - * - * A reference of the compilation unit (DW_TAG_compile_unit) is - * needed because the default lower bound (when there is no DW_AT_lower_bound) - * depends of the language of the compilation unit (DW_AT_language). - * - * @param die DIE for the DW_TAG_enumeration_type or DW_TAG_subrange_type - * @param unit DIE of the DW_TAG_compile_unit - */ -static uint64_t MC_dwarf_subrange_element_count(Dwarf_Die* die, Dwarf_Die* unit); - -/** @brief Computes the number of elements of a given DW_TAG_array_type. - * - * @param die DIE for the DW_TAG_array_type - */ -static uint64_t MC_dwarf_array_element_count(Dwarf_Die* die, Dwarf_Die* unit); - -/** @brief Process a DIE - * - * @param info the resulting object for the library/binary file (output) - * @param die the current DIE - * @param unit the DIE of the compile unit of the current DIE - * @param frame containing frame if any - */ -static void MC_dwarf_handle_die(simgrid::mc::ObjectInformation* info, Dwarf_Die* die, Dwarf_Die* unit, - simgrid::mc::Frame* frame, const char* ns); - -/** @brief Process a type DIE - */ -static void MC_dwarf_handle_type_die(simgrid::mc::ObjectInformation* info, Dwarf_Die* die, Dwarf_Die* unit, - simgrid::mc::Frame* frame, const char* ns); - -/** @brief Calls MC_dwarf_handle_die on all children of the given die - * - * @param info the resulting object for the library/binary file (output) - * @param die the current DIE - * @param unit the DIE of the compile unit of the current DIE - * @param frame containing frame if any - */ -static void MC_dwarf_handle_children(simgrid::mc::ObjectInformation* info, Dwarf_Die* die, Dwarf_Die* unit, - simgrid::mc::Frame* frame, const char* ns); - -/** @brief Handle a variable (DW_TAG_variable or other) - * - * @param info the resulting object for the library/binary file (output) - * @param die the current DIE - * @param unit the DIE of the compile unit of the current DIE - * @param frame containing frame if any - */ -static void MC_dwarf_handle_variable_die(simgrid::mc::ObjectInformation* info, Dwarf_Die* die, const Dwarf_Die* unit, - simgrid::mc::Frame* frame, const char* ns); - -/** @brief Get the DW_TAG_type of the DIE - * - * @param die DIE - * @return DW_TAG_type attribute as a new string (nullptr if none) - */ -static std::uint64_t MC_dwarf_at_type(Dwarf_Die* die); - -namespace simgrid::dwarf { - -enum class TagClass { Unknown, Type, Subprogram, Variable, Scope, Namespace }; - -/*** Class of forms defined in the DWARF standard */ -enum class FormClass { - Unknown, - Address, // Location in the program's address space - Block, // Arbitrary block of bytes - Constant, - String, - Flag, // Boolean value - Reference, // Reference to another DIE - ExprLoc, // DWARF expression/location description - LinePtr, - LocListPtr, - MacPtr, - RangeListPtr -}; - -static TagClass classify_tag(int tag) -{ - static const std::unordered_map map = { - {DW_TAG_array_type, TagClass::Type}, {DW_TAG_class_type, TagClass::Type}, - {DW_TAG_enumeration_type, TagClass::Type}, {DW_TAG_typedef, TagClass::Type}, - {DW_TAG_pointer_type, TagClass::Type}, {DW_TAG_reference_type, TagClass::Type}, - {DW_TAG_rvalue_reference_type, TagClass::Type}, {DW_TAG_string_type, TagClass::Type}, - {DW_TAG_structure_type, TagClass::Type}, {DW_TAG_subroutine_type, TagClass::Type}, - {DW_TAG_union_type, TagClass::Type}, {DW_TAG_ptr_to_member_type, TagClass::Type}, - {DW_TAG_set_type, TagClass::Type}, {DW_TAG_subrange_type, TagClass::Type}, - {DW_TAG_base_type, TagClass::Type}, {DW_TAG_const_type, TagClass::Type}, - {DW_TAG_file_type, TagClass::Type}, {DW_TAG_packed_type, TagClass::Type}, - {DW_TAG_volatile_type, TagClass::Type}, {DW_TAG_restrict_type, TagClass::Type}, - {DW_TAG_interface_type, TagClass::Type}, {DW_TAG_unspecified_type, TagClass::Type}, - {DW_TAG_shared_type, TagClass::Type}, - - {DW_TAG_subprogram, TagClass::Subprogram}, - - {DW_TAG_variable, TagClass::Variable}, {DW_TAG_formal_parameter, TagClass::Variable}, - - {DW_TAG_lexical_block, TagClass::Scope}, {DW_TAG_try_block, TagClass::Scope}, - {DW_TAG_catch_block, TagClass::Scope}, {DW_TAG_inlined_subroutine, TagClass::Scope}, - {DW_TAG_with_stmt, TagClass::Scope}, - - {DW_TAG_namespace, TagClass::Namespace}}; - - auto res = map.find(tag); - return res != map.end() ? res->second : TagClass::Unknown; -} - -/** @brief Find the DWARF data class for a given DWARF data form - * - * This mapping is defined in the DWARF spec. - * - * @param form The form (values taken from the DWARF spec) - * @return An internal representation for the corresponding class - * */ -static FormClass classify_form(int form) -{ - static const std::unordered_map map = { - {DW_FORM_addr, FormClass::Address}, - - {DW_FORM_block2, FormClass::Block}, {DW_FORM_block4, FormClass::Block}, - {DW_FORM_block, FormClass::Block}, {DW_FORM_block1, FormClass::Block}, - - {DW_FORM_data1, FormClass::Constant}, {DW_FORM_data2, FormClass::Constant}, - {DW_FORM_data4, FormClass::Constant}, {DW_FORM_data8, FormClass::Constant}, - {DW_FORM_udata, FormClass::Constant}, {DW_FORM_sdata, FormClass::Constant}, -#if _ELFUTILS_PREREQ(0, 171) - {DW_FORM_implicit_const, FormClass::Constant}, -#endif - - {DW_FORM_string, FormClass::String}, {DW_FORM_strp, FormClass::String}, - - {DW_FORM_ref_addr, FormClass::Reference}, {DW_FORM_ref1, FormClass::Reference}, - {DW_FORM_ref2, FormClass::Reference}, {DW_FORM_ref4, FormClass::Reference}, - {DW_FORM_ref8, FormClass::Reference}, {DW_FORM_ref_udata, FormClass::Reference}, - - {DW_FORM_flag, FormClass::Flag}, {DW_FORM_flag_present, FormClass::Flag}, - - {DW_FORM_exprloc, FormClass::ExprLoc} - - // TODO sec offset - // TODO indirect - }; - - auto res = map.find(form); - return res != map.end() ? res->second : FormClass::Unknown; -} - -/** @brief Get the name of the tag of a given DIE - * - * @param die DIE - * @return name of the tag of this DIE - */ -inline XBT_PRIVATE const char* tagname(Dwarf_Die* die) -{ - return tagname(dwarf_tag(die)); -} - -} // namespace simgrid::dwarf - -// ***** Attributes - -/** @brief Get an attribute of a given DIE as a string - * - * @param die the DIE - * @param attribute attribute - * @return value of the given attribute of the given DIE - */ -static const char* MC_dwarf_attr_integrate_string(Dwarf_Die* die, int attribute) -{ - Dwarf_Attribute attr; - if (not dwarf_attr_integrate(die, attribute, &attr)) - return nullptr; - else - return dwarf_formstring(&attr); -} - -static Dwarf_Off MC_dwarf_attr_integrate_dieoffset(Dwarf_Die* die, int attribute) -{ - Dwarf_Attribute attr; - if (dwarf_hasattr_integrate(die, attribute) == 0) - return 0; - dwarf_attr_integrate(die, attribute, &attr); - Dwarf_Die subtype_die; - xbt_assert(dwarf_formref_die(&attr, &subtype_die) != nullptr, "Could not find DIE"); - return dwarf_dieoffset(&subtype_die); -} - -/** @brief Find the type/subtype (DW_AT_type) for a DIE - * - * @param die the DIE - * @return DW_AT_type reference as a global offset in hexadecimal (or nullptr) - */ -static std::uint64_t MC_dwarf_at_type(Dwarf_Die* die) -{ - return MC_dwarf_attr_integrate_dieoffset(die, DW_AT_type); -} - -static uint64_t MC_dwarf_attr_integrate_addr(Dwarf_Die* die, int attribute) -{ - Dwarf_Attribute attr; - if (dwarf_attr_integrate(die, attribute, &attr) == nullptr) - return 0; - Dwarf_Addr value; - if (dwarf_formaddr(&attr, &value) == 0) - return (uint64_t)value; - else - return 0; -} - -static uint64_t MC_dwarf_attr_integrate_uint(Dwarf_Die* die, int attribute, uint64_t default_value) -{ - Dwarf_Attribute attr; - if (dwarf_attr_integrate(die, attribute, &attr) == nullptr) - return default_value; - Dwarf_Word value; - return dwarf_formudata(dwarf_attr_integrate(die, attribute, &attr), &value) == 0 ? (uint64_t)value : default_value; -} - -static bool MC_dwarf_attr_flag(Dwarf_Die* die, int attribute, bool integrate) -{ - Dwarf_Attribute attr; - if ((integrate ? dwarf_attr_integrate(die, attribute, &attr) : dwarf_attr(die, attribute, &attr)) == nullptr) - return false; - - bool result; - xbt_assert(not dwarf_formflag(&attr, &result), "Unexpected form for attribute %s", - simgrid::dwarf::attrname(attribute)); - return result; -} - -/** @brief Find the default lower bound for a given language - * - * The default lower bound of an array (when DW_TAG_lower_bound - * is missing) depends on the language of the compilation unit. - * - * @param lang Language of the compilation unit (values defined in the DWARF spec) - * @return Default lower bound of an array in this compilation unit - * */ -static uint64_t MC_dwarf_default_lower_bound(int lang) -{ - const std::unordered_map map = { - {DW_LANG_C, 0}, {DW_LANG_C89, 0}, {DW_LANG_C99, 0}, {DW_LANG_C11, 0}, - {DW_LANG_C_plus_plus, 0}, {DW_LANG_C_plus_plus_11, 0}, {DW_LANG_C_plus_plus_14, 0}, {DW_LANG_D, 0}, - {DW_LANG_Java, 0}, {DW_LANG_ObjC, 0}, {DW_LANG_ObjC_plus_plus, 0}, {DW_LANG_Python, 0}, - {DW_LANG_UPC, 0}, - - {DW_LANG_Ada83, 1}, {DW_LANG_Ada95, 1}, {DW_LANG_Fortran77, 1}, {DW_LANG_Fortran90, 1}, - {DW_LANG_Fortran95, 1}, {DW_LANG_Fortran03, 1}, {DW_LANG_Fortran08, 1}, {DW_LANG_Modula2, 1}, - {DW_LANG_Pascal83, 1}, {DW_LANG_PL1, 1}, {DW_LANG_Cobol74, 1}, {DW_LANG_Cobol85, 1}}; - - auto res = map.find(lang); - xbt_assert(res != map.end(), "No default DW_TAG_lower_bound for language %i and none given", lang); - return res->second; -} - -/** @brief Finds the number of elements in a DW_TAG_subrange_type or DW_TAG_enumeration_type DIE - * - * @param die the DIE - * @param unit DIE of the compilation unit - * @return number of elements in the range - * */ -static uint64_t MC_dwarf_subrange_element_count(Dwarf_Die* die, Dwarf_Die* unit) -{ - xbt_assert(dwarf_tag(die) == DW_TAG_enumeration_type || dwarf_tag(die) == DW_TAG_subrange_type, - "MC_dwarf_subrange_element_count called with DIE of type %s", simgrid::dwarf::tagname(die)); - - // Use DW_TAG_count if present: - if (dwarf_hasattr_integrate(die, DW_AT_count)) - return MC_dwarf_attr_integrate_uint(die, DW_AT_count, 0); - // Otherwise compute DW_TAG_upper_bound-DW_TAG_lower_bound + 1: - - if (not dwarf_hasattr_integrate(die, DW_AT_upper_bound)) - // This is not really 0, but the code expects this (we do not know): - return 0; - - uint64_t upper_bound = MC_dwarf_attr_integrate_uint(die, DW_AT_upper_bound, static_cast(-1)); - - uint64_t lower_bound = 0; - if (dwarf_hasattr_integrate(die, DW_AT_lower_bound)) - lower_bound = MC_dwarf_attr_integrate_uint(die, DW_AT_lower_bound, static_cast(-1)); - else - lower_bound = MC_dwarf_default_lower_bound(dwarf_srclang(unit)); - return upper_bound - lower_bound + 1; -} - -/** @brief Finds the number of elements in an array type (DW_TAG_array_type) - * - * The compilation unit might be needed because the default lower - * bound depends on the language of the compilation unit. - * - * @param die the DIE of the DW_TAG_array_type - * @param unit the DIE of the compilation unit - * @return number of elements in this array type - * */ -static uint64_t MC_dwarf_array_element_count(Dwarf_Die* die, Dwarf_Die* unit) -{ - xbt_assert(dwarf_tag(die) == DW_TAG_array_type, "MC_dwarf_array_element_count called with DIE of type %s", - simgrid::dwarf::tagname(die)); - - int result = 1; - Dwarf_Die child; - for (int res = dwarf_child(die, &child); res == 0; res = dwarf_siblingof(&child, &child)) { - int child_tag = dwarf_tag(&child); - if (child_tag == DW_TAG_subrange_type || child_tag == DW_TAG_enumeration_type) - result *= MC_dwarf_subrange_element_count(&child, unit); - } - return result; -} - -// ***** Variable - -/** Sort the variable by name and address. - * - * We could use boost::container::flat_set instead. - */ -static bool MC_compare_variable(simgrid::mc::Variable const& a, simgrid::mc::Variable const& b) -{ - int cmp = a.name.compare(b.name); - if (cmp < 0) - return true; - else if (cmp > 0) - return false; - else - return a.address < b.address; -} - -// ***** simgrid::mc::Type* - -/** @brief Initialize the location of a member of a type - * (DW_AT_data_member_location of a DW_TAG_member). - * - * @param type a type (struct, class) - * @param member the member of the type - * @param child DIE of the member (DW_TAG_member) - */ -static void MC_dwarf_fill_member_location(const simgrid::mc::Type* type, simgrid::mc::Member* member, Dwarf_Die* child) -{ - xbt_assert(not dwarf_hasattr(child, DW_AT_data_bit_offset), "Can't groke DW_AT_data_bit_offset."); - - if (not dwarf_hasattr_integrate(child, DW_AT_data_member_location)) { - xbt_assert(type->type == DW_TAG_union_type, - "Missing DW_AT_data_member_location field in DW_TAG_member %s of type <%" PRIx64 ">%s", - member->name.c_str(), (uint64_t)type->id, type->name.c_str()); - return; - } - - Dwarf_Attribute attr; - dwarf_attr_integrate(child, DW_AT_data_member_location, &attr); - int form = dwarf_whatform(&attr); - simgrid::dwarf::FormClass form_class = simgrid::dwarf::classify_form(form); - switch (form_class) { - case simgrid::dwarf::FormClass::ExprLoc: - case simgrid::dwarf::FormClass::Block: - // Location expression: - { - Dwarf_Op* expr; - size_t len; - xbt_assert(not dwarf_getlocation(&attr, &expr, &len), - "Could not read location expression DW_AT_data_member_location in DW_TAG_member %s of type <%" PRIx64 - ">%s", - MC_dwarf_attr_integrate_string(child, DW_AT_name), (uint64_t)type->id, type->name.c_str()); - member->location_expression = simgrid::dwarf::DwarfExpression(expr, expr + len); - break; - } - case simgrid::dwarf::FormClass::Constant: - // Offset from the base address of the object: - { - Dwarf_Word offset; - xbt_assert(not dwarf_formudata(&attr, &offset), "Cannot get %s location <%" PRIx64 ">%s", - MC_dwarf_attr_integrate_string(child, DW_AT_name), (uint64_t)type->id, type->name.c_str()); - member->offset(offset); - break; - } - - default: - // includes FormClass::LocListPtr (reference to a location list: TODO) and FormClass::Reference (it's supposed to - // be possible in DWARF2 but I couldn't find its semantic in the spec) - xbt_die("Can't handle form class (%d) / form 0x%x as DW_AT_member_location", (int)form_class, (unsigned)form); - } -} - -/** @brief Populate the list of members of a type - * - * @param info ELF object containing the type DIE - * @param die DIE of the type - * @param unit DIE of the compilation unit containing the type DIE - * @param type the type - */ -static void MC_dwarf_add_members(const simgrid::mc::ObjectInformation* /*info*/, Dwarf_Die* die, - const Dwarf_Die* /*unit*/, simgrid::mc::Type* type) -{ - Dwarf_Die child; - xbt_assert(type->members.empty()); - for (int res = dwarf_child(die, &child); res == 0; res = dwarf_siblingof(&child, &child)) { - int tag = dwarf_tag(&child); - if (tag == DW_TAG_member || tag == DW_TAG_inheritance) { - // Skip declarations: - if (MC_dwarf_attr_flag(&child, DW_AT_declaration, false)) - continue; - - // Skip compile time constants: - if (dwarf_hasattr(&child, DW_AT_const_value)) - continue; - - // TODO, we should use another type (because is is not a type but a member) - simgrid::mc::Member member; - if (tag == DW_TAG_inheritance) - member.flags |= simgrid::mc::Member::INHERITANCE_FLAG; - - const char* name = MC_dwarf_attr_integrate_string(&child, DW_AT_name); - if (name) - member.name = name; - // Those base names are used by GCC and clang for virtual table pointers - // respectively ("__vptr$ClassName", "__vptr.ClassName"): - if (member.name.rfind("__vptr$", 0) == 0 || member.name.rfind("__vptr.", 0) == 0) - member.flags |= simgrid::mc::Member::VIRTUAL_POINTER_FLAG; - // A cleaner solution would be to check against the type: - // --- - // tag: DW_TAG_member - // name: "_vptr$Foo" - // type: - // # Type for a pointer to a vtable - // tag: DW_TAG_pointer_type - // type: - // # Type for a vtable: - // tag: DW_TAG_pointer_type - // name: "__vtbl_ptr_type" - // type: - // tag: DW_TAG_subroutine_type - // type: - // tag: DW_TAG_base_type - // name: "int" - // --- - - member.byte_size = MC_dwarf_attr_integrate_uint(&child, DW_AT_byte_size, 0); - member.type_id = MC_dwarf_at_type(&child); - - if (dwarf_hasattr(&child, DW_AT_data_bit_offset)) { - XBT_WARN("Can't groke DW_AT_data_bit_offset for %s", name); - continue; - } - - MC_dwarf_fill_member_location(type, &member, &child); - - xbt_assert(member.type_id, "Missing type for member %s of <%" PRIx64 ">%s", member.name.c_str(), - (uint64_t)type->id, type->name.c_str()); - - type->members.push_back(std::move(member)); - } - } -} - -/** @brief Create a MC type object from a DIE - * - * @param info current object info object - * @param die DIE (for a given type) - * @param unit compilation unit of the current DIE - * @return MC representation of the type - */ -static simgrid::mc::Type MC_dwarf_die_to_type(simgrid::mc::ObjectInformation* info, Dwarf_Die* die, Dwarf_Die* unit, - simgrid::mc::Frame* frame, const char* ns) -{ - simgrid::mc::Type type; - type.type = dwarf_tag(die); - type.name = std::string(); - type.element_count = -1; - - // Global Offset - type.id = dwarf_dieoffset(die); - - const char* prefix = ""; - switch (type.type) { - case DW_TAG_structure_type: - prefix = "struct "; - break; - case DW_TAG_union_type: - prefix = "union "; - break; - case DW_TAG_class_type: - prefix = "class "; - break; - default: - prefix = ""; - } - - const char* name = MC_dwarf_attr_integrate_string(die, DW_AT_name); - if (name != nullptr) { - if (ns) - type.name = simgrid::xbt::string_printf("%s%s::%s", prefix, ns, name); - else - type.name = simgrid::xbt::string_printf("%s%s", prefix, name); - } - - type.type_id = MC_dwarf_at_type(die); - - // Some compilers do not emit DW_AT_byte_size for pointer_type, - // so we fill this. We currently assume that the model-checked process is in - // the same architecture.. - if (type.type == DW_TAG_pointer_type) - type.byte_size = sizeof(void*); - - // Computation of the byte_size - if (dwarf_hasattr_integrate(die, DW_AT_byte_size)) - type.byte_size = MC_dwarf_attr_integrate_uint(die, DW_AT_byte_size, 0); - else if (type.type == DW_TAG_array_type || type.type == DW_TAG_structure_type || type.type == DW_TAG_class_type) { - Dwarf_Word size; - if (dwarf_aggregate_size(die, &size) == 0) - type.byte_size = size; - } - - switch (type.type) { - case DW_TAG_array_type: - type.element_count = MC_dwarf_array_element_count(die, unit); - // TODO, handle DW_byte_stride and (not) DW_bit_stride - break; - - case DW_TAG_pointer_type: - case DW_TAG_reference_type: - case DW_TAG_rvalue_reference_type: - break; - - case DW_TAG_structure_type: - case DW_TAG_union_type: - case DW_TAG_class_type: - MC_dwarf_add_members(info, die, unit, &type); - MC_dwarf_handle_children(info, die, unit, frame, - ns ? simgrid::xbt::string_printf("%s::%s", ns, name).c_str() : type.name.c_str()); - break; - - default: - XBT_DEBUG("Unhandled type: %d (%s)", type.type, simgrid::dwarf::tagname(type.type)); - break; - } - - return type; -} - -static void MC_dwarf_handle_type_die(simgrid::mc::ObjectInformation* info, Dwarf_Die* die, Dwarf_Die* unit, - simgrid::mc::Frame* frame, const char* ns) -{ - simgrid::mc::Type type = MC_dwarf_die_to_type(info, die, unit, frame, ns); - auto& t = (info->types[type.id] = std::move(type)); - if (not t.name.empty() && type.byte_size != 0) - info->full_types_by_name[t.name] = &t; -} - -static std::unique_ptr MC_die_to_variable(simgrid::mc::ObjectInformation* info, Dwarf_Die* die, - const Dwarf_Die* /*unit*/, - const simgrid::mc::Frame* frame, const char* ns) -{ - // Skip declarations: - if (MC_dwarf_attr_flag(die, DW_AT_declaration, false)) - return nullptr; - - // Skip compile time constants: - if (dwarf_hasattr(die, DW_AT_const_value)) - return nullptr; - - Dwarf_Attribute attr_location; - if (dwarf_attr(die, DW_AT_location, &attr_location) == nullptr) - // No location: do not add it ? - return nullptr; - - auto variable = std::make_unique(); - variable->id = dwarf_dieoffset(die); - variable->global = frame == nullptr; // Can be override base on DW_AT_location - variable->object_info = info; - - const char* name = MC_dwarf_attr_integrate_string(die, DW_AT_name); - if (name) - variable->name = name; - variable->type_id = MC_dwarf_at_type(die); - - int form = dwarf_whatform(&attr_location); - simgrid::dwarf::FormClass form_class; - if (form == DW_FORM_sec_offset) - form_class = simgrid::dwarf::FormClass::Constant; - else - form_class = simgrid::dwarf::classify_form(form); - switch (form_class) { - case simgrid::dwarf::FormClass::ExprLoc: - case simgrid::dwarf::FormClass::Block: - // Location expression: - { - Dwarf_Op* expr; - size_t len; - xbt_assert(not dwarf_getlocation(&attr_location, &expr, &len), - "Could not read location expression in DW_AT_location " - "of variable <%" PRIx64 ">%s", - (uint64_t)variable->id, variable->name.c_str()); - - if (len == 1 && expr[0].atom == DW_OP_addr) { - variable->global = true; - auto offset = static_cast(expr[0].number); - auto base = reinterpret_cast(info->base_address()); - variable->address = reinterpret_cast(base + offset); - } else - variable->location_list = { - simgrid::dwarf::LocationListEntry(simgrid::dwarf::DwarfExpression(expr, expr + len))}; - - break; - } - - case simgrid::dwarf::FormClass::LocListPtr: - case simgrid::dwarf::FormClass::Constant: - // Reference to location list: - variable->location_list = simgrid::dwarf::location_list(*info, attr_location); - break; - - default: - xbt_die("Unexpected form 0x%x (%i), class 0x%x (%i) list for location in <%" PRIx64 ">%s", (unsigned)form, form, - (unsigned)form_class, (int)form_class, (uint64_t)variable->id, variable->name.c_str()); - } - - // Handle start_scope: - if (dwarf_hasattr(die, DW_AT_start_scope)) { - Dwarf_Attribute attr; - dwarf_attr(die, DW_AT_start_scope, &attr); - form = dwarf_whatform(&attr); - form_class = simgrid::dwarf::classify_form(form); - if (form_class == simgrid::dwarf::FormClass::Constant) { - Dwarf_Word value; - variable->start_scope = dwarf_formudata(&attr, &value) == 0 ? (size_t)value : 0; - } else { - // TODO: FormClass::RangeListPtr - xbt_die("Unhandled form 0x%x, class 0x%X for DW_AT_start_scope of variable %s", (unsigned)form, - (unsigned)form_class, name == nullptr ? "?" : name); - } - } - - if (ns && variable->global) - variable->name = std::string(ns) + "::" + variable->name; - - // The current code needs a variable name, - // generate a fake one: - static int mc_anonymous_variable_index = 0; - if (variable->name.empty()) { - variable->name = "@anonymous#" + std::to_string(mc_anonymous_variable_index); - mc_anonymous_variable_index++; - } - return variable; -} - -static void MC_dwarf_handle_variable_die(simgrid::mc::ObjectInformation* info, Dwarf_Die* die, const Dwarf_Die* unit, - simgrid::mc::Frame* frame, const char* ns) -{ - std::unique_ptr variable = MC_die_to_variable(info, die, unit, frame, ns); - if (not variable) - return; - // Those arrays are sorted later: - if (variable->global) - info->global_variables.push_back(std::move(*variable)); - else if (frame != nullptr) - frame->variables.push_back(std::move(*variable)); - else - xbt_die("No frame for this local variable"); -} - -static void MC_dwarf_handle_scope_die(simgrid::mc::ObjectInformation* info, Dwarf_Die* die, Dwarf_Die* unit, - simgrid::mc::Frame* parent_frame, const char* ns) -{ - // TODO, handle DW_TAG_type/DW_TAG_location for DW_TAG_with_stmt - int tag = dwarf_tag(die); - simgrid::dwarf::TagClass klass = simgrid::dwarf::classify_tag(tag); - - // (Template) Subprogram declaration: - if (klass == simgrid::dwarf::TagClass::Subprogram && MC_dwarf_attr_flag(die, DW_AT_declaration, false)) - return; - - if (klass == simgrid::dwarf::TagClass::Scope) - xbt_assert(parent_frame, "No parent scope for this scope"); - - simgrid::mc::Frame frame; - frame.tag = tag; - frame.id = dwarf_dieoffset(die); - frame.object_info = info; - - if (klass == simgrid::dwarf::TagClass::Subprogram) { - const char* name = MC_dwarf_attr_integrate_string(die, DW_AT_name); - if (name && ns) - frame.name = std::string(ns) + "::" + name; - else if (name) - frame.name = name; - } - - frame.abstract_origin_id = MC_dwarf_attr_integrate_dieoffset(die, DW_AT_abstract_origin); - - // This is the base address for DWARF addresses. - // Relocated addresses are offset from this base address. - // See DWARF4 spec 7.5 - auto base = reinterpret_cast(info->base_address()); - - // TODO, support DW_AT_ranges - uint64_t low_pc = MC_dwarf_attr_integrate_addr(die, DW_AT_low_pc); - frame.range.begin() = low_pc ? base + low_pc : 0; - if (low_pc) { - // DW_AT_high_pc: - Dwarf_Attribute attr; - xbt_assert(dwarf_attr_integrate(die, DW_AT_high_pc, &attr), "Missing DW_AT_high_pc matching with DW_AT_low_pc"); - - Dwarf_Sword offset; - Dwarf_Addr high_pc; - - switch (simgrid::dwarf::classify_form(dwarf_whatform(&attr))) { - // DW_AT_high_pc if an offset from the low_pc: - case simgrid::dwarf::FormClass::Constant: - - xbt_assert(dwarf_formsdata(&attr, &offset) == 0, "Could not read constant"); - frame.range.end() = frame.range.begin() + offset; - break; - - // DW_AT_high_pc is a relocatable address: - case simgrid::dwarf::FormClass::Address: - xbt_assert(dwarf_formaddr(&attr, &high_pc) == 0, "Could not read address"); - frame.range.end() = base + high_pc; - break; - - default: - xbt_die("Unexpected class for DW_AT_high_pc"); - } - } - - if (klass == simgrid::dwarf::TagClass::Subprogram) { - Dwarf_Attribute attr_frame_base; - if (dwarf_attr_integrate(die, DW_AT_frame_base, &attr_frame_base)) - frame.frame_base_location = simgrid::dwarf::location_list(*info, attr_frame_base); - } - - // Handle children: - MC_dwarf_handle_children(info, die, unit, &frame, ns); - - // We sort them in order to have an (somewhat) efficient by name - // lookup: - boost::range::sort(frame.variables, MC_compare_variable); - - // Register it: - if (klass == simgrid::dwarf::TagClass::Subprogram) - info->subprograms[frame.id] = std::move(frame); - else if (klass == simgrid::dwarf::TagClass::Scope) - parent_frame->scopes.push_back(std::move(frame)); -} - -static void mc_dwarf_handle_namespace_die(simgrid::mc::ObjectInformation* info, Dwarf_Die* die, Dwarf_Die* unit, - simgrid::mc::Frame* frame, const char* ns) -{ - const char* name = MC_dwarf_attr_integrate_string(die, DW_AT_name); - xbt_assert(not frame, "Unexpected namespace in a subprogram"); - char* new_ns = ns == nullptr ? xbt_strdup(name) : bprintf("%s::%s", ns, name); - MC_dwarf_handle_children(info, die, unit, frame, new_ns); - xbt_free(new_ns); -} - -static void MC_dwarf_handle_children(simgrid::mc::ObjectInformation* info, Dwarf_Die* die, Dwarf_Die* unit, - simgrid::mc::Frame* frame, const char* ns) -{ - // For each child DIE: - Dwarf_Die child; - for (int res = dwarf_child(die, &child); res == 0; res = dwarf_siblingof(&child, &child)) - MC_dwarf_handle_die(info, &child, unit, frame, ns); -} - -static void MC_dwarf_handle_die(simgrid::mc::ObjectInformation* info, Dwarf_Die* die, Dwarf_Die* unit, - simgrid::mc::Frame* frame, const char* ns) -{ - int tag = dwarf_tag(die); - simgrid::dwarf::TagClass klass = simgrid::dwarf::classify_tag(tag); - switch (klass) { - // Type: - case simgrid::dwarf::TagClass::Type: - MC_dwarf_handle_type_die(info, die, unit, frame, ns); - break; - - // Subprogram or scope: - case simgrid::dwarf::TagClass::Subprogram: - case simgrid::dwarf::TagClass::Scope: - MC_dwarf_handle_scope_die(info, die, unit, frame, ns); - return; - - // Variable: - case simgrid::dwarf::TagClass::Variable: - MC_dwarf_handle_variable_die(info, die, unit, frame, ns); - break; - - case simgrid::dwarf::TagClass::Namespace: - mc_dwarf_handle_namespace_die(info, die, unit, frame, ns); - break; - - default: - break; - } -} - -static Elf64_Half get_type(Elf* elf) -{ - if (const Elf64_Ehdr* ehdr64 = elf64_getehdr(elf)) - return ehdr64->e_type; - if (const Elf32_Ehdr* ehdr32 = elf32_getehdr(elf)) - return ehdr32->e_type; - xbt_die("Could not get ELF heeader"); -} - -static void read_dwarf_info(simgrid::mc::ObjectInformation* info, Dwarf* dwarf) -{ - // For each compilation unit: - Dwarf_Off offset = 0; - Dwarf_Off next_offset = 0; - size_t length; - - while (dwarf_nextcu(dwarf, offset, &next_offset, &length, nullptr, nullptr, nullptr) == 0) { - if (Dwarf_Die unit_die; dwarf_offdie(dwarf, offset + length, &unit_die) != nullptr) - MC_dwarf_handle_children(info, &unit_die, &unit_die, nullptr, nullptr); - offset = next_offset; - } -} - -/** Get the build-id (NT_GNU_BUILD_ID) from the ELF file - * - * This build-id may is used to locate an external debug (DWARF) file - * for this ELF file. - * - * @param elf libelf handle for an ELF file - * @return build-id for this ELF file (or an empty vector if none is found) - */ -static std::vector get_build_id(Elf* elf) -{ -#ifdef __linux - // Summary: the GNU build ID is stored in a ("GNU, NT_GNU_BUILD_ID) note - // found in a PT_NOTE entry in the program header table. - - size_t phnum; - xbt_assert(elf_getphdrnum(elf, &phnum) == 0, "Could not read program headers"); - - // Iterate over the program headers and find the PT_NOTE ones: - for (size_t i = 0; i < phnum; ++i) { - GElf_Phdr phdr_temp; - const GElf_Phdr* phdr = gelf_getphdr(elf, i, &phdr_temp); - if (phdr->p_type != PT_NOTE) - continue; - - Elf_Data* data = elf_getdata_rawchunk(elf, phdr->p_offset, phdr->p_filesz, ELF_T_NHDR); - - // Iterate over the notes and find the NT_GNU_BUILD_ID one: - size_t pos = 0; - while (pos < data->d_size) { - GElf_Nhdr nhdr; - // Location of the name within Elf_Data: - size_t name_pos; - size_t desc_pos; - pos = gelf_getnote(data, pos, &nhdr, &name_pos, &desc_pos); - // A build ID note is identified by the pair ("GNU", NT_GNU_BUILD_ID) - // (a namespace and a type within this namespace): - if (nhdr.n_type == NT_GNU_BUILD_ID && nhdr.n_namesz == sizeof("GNU") && - memcmp((char*)data->d_buf + name_pos, "GNU", sizeof("GNU")) == 0) { - XBT_DEBUG("Found GNU/NT_GNU_BUILD_ID note"); - char* start = (char*)data->d_buf + desc_pos; - char* end = start + nhdr.n_descsz; - return std::vector(start, end); - } - } - } -#endif - return std::vector(); -} - -/** Binary data to hexadecimal */ -static inline std::array to_hex(std::uint8_t byte) -{ - constexpr std::array hexdigits{ - {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}}; - // Horrid double braces! - // Apparently, this is needed in C++11 (not in C++14). - return {{hexdigits[byte >> 4], hexdigits[byte & 0xF]}}; -} - -/** Binary data to hexadecimal */ -static std::string to_hex(const char* data, std::size_t count) -{ - std::string res; - res.resize(2 * count); - for (std::size_t i = 0; i < count; i++) - std::copy_n(cbegin(to_hex(data[i])), 2, &res[2 * i]); - return res; -} - -/** Binary data to hexadecimal */ -static std::string to_hex(std::vector const& data) -{ - return to_hex(data.data(), data.size()); -} - -/** Base directories for external debug files */ -static constexpr auto debug_paths = { - "/usr/lib/debug/", - "/usr/local/lib/debug/", -}; - -/** Locate an external debug file from the NT_GNU_BUILD_ID - * - * This is one of the mechanisms used for - * [separate debug files](https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html). - */ -// Example: -// /usr/lib/debug/.build-id/0b/dc77f1c29aea2b14ff5acd9a19ab3175ffdeae.debug -static int find_by_build_id(std::vector id) -{ - std::string filename; - std::string hex = to_hex(id); - for (const char* const& debug_path : debug_paths) { - // Example: - filename = std::string(debug_path) + ".build-id/" + to_hex(id.data(), 1) + '/' + - to_hex(id.data() + 1, id.size() - 1) + ".debug"; - XBT_DEBUG("Checking debug file: %s", filename.c_str()); - if (int fd = open(filename.c_str(), O_RDONLY); fd != -1) { - XBT_DEBUG("Found debug file: %s\n", hex.c_str()); - return fd; - } - xbt_assert(errno != ENOENT, "Could not open file: %s", strerror(errno)); - } - XBT_DEBUG("No debug info found for build ID %s\n", hex.data()); - return -1; -} - -/** @brief Populate the debugging information of the given ELF object - * - * Read the DWARF information of the ELF object and populate the - * lists of types, variables, functions. - */ -static void MC_load_dwarf(simgrid::mc::ObjectInformation* info) -{ - xbt_assert(elf_version(EV_CURRENT) != EV_NONE, "libelf initialization error"); - - // Open the ELF file: - int fd = open(info->file_name.c_str(), O_RDONLY); - xbt_assert(fd >= 0, "Could not open file %s", info->file_name.c_str()); - Elf* elf = elf_begin(fd, ELF_C_READ, nullptr); - xbt_assert(elf != nullptr && elf_kind(elf) == ELF_K_ELF, "%s is not an ELF file", info->file_name.c_str()); - - // Remember if this is a `ET_EXEC` (fixed location) or `ET_DYN`: - if (get_type(elf) == ET_EXEC) - info->flags |= simgrid::mc::ObjectInformation::Executable; - - // Read DWARF debug information in the file: - if (Dwarf* dwarf = dwarf_begin_elf(elf, DWARF_C_READ, nullptr)) { - read_dwarf_info(info, dwarf); - dwarf_end(dwarf); - elf_end(elf); - close(fd); - return; - } - - // If there was no DWARF in the file, try to find it in a separate file. - // Different methods might be used to store the DWARF information: - // * GNU NT_GNU_BUILD_ID - // * .gnu_debuglink - // See https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html - // for reference of what we are doing. - - // Try with NT_GNU_BUILD_ID: we find the build ID in the ELF file and then - // use this ID to find the file in some known locations in the filesystem. - if (std::vector build_id = get_build_id(elf); not build_id.empty()) { - elf_end(elf); - close(fd); - - // Find the debug file using the build id: - fd = find_by_build_id(build_id); - xbt_assert(fd != -1, - "Missing debug info for %s with build-id %s\n" - "You might want to install the suitable debugging package.\n", - info->file_name.c_str(), to_hex(build_id).c_str()); - - // Load the DWARF info from this file: - XBT_DEBUG("Load DWARF for %s", info->file_name.c_str()); - Dwarf* dwarf = dwarf_begin(fd, DWARF_C_READ); - xbt_assert(dwarf != nullptr, "No DWARF info for %s", info->file_name.c_str()); - read_dwarf_info(info, dwarf); - dwarf_end(dwarf); - close(fd); - return; - } - - // TODO, try to find DWARF info using .gnu_debuglink. - - elf_end(elf); - close(fd); - xbt_die("Debugging information not found for %s\n" - "Try recompiling with -g\n", - info->file_name.c_str()); -} - -// ***** Functions index - -static void MC_make_functions_index(simgrid::mc::ObjectInformation* info) -{ - info->functions_index.clear(); - - for (auto& [_, e] : info->subprograms) { - if (e.range.begin() == 0) - continue; - simgrid::mc::FunctionIndexEntry entry; - entry.low_pc = (void*)e.range.begin(); - entry.function = &e; - info->functions_index.push_back(entry); - } - - info->functions_index.shrink_to_fit(); - - // Sort the array by low_pc: - boost::range::sort(info->functions_index, - [](simgrid::mc::FunctionIndexEntry const& a, simgrid::mc::FunctionIndexEntry const& b) { - return a.low_pc < b.low_pc; - }); -} - -static void MC_post_process_variables(simgrid::mc::ObjectInformation* info) -{ - // Someone needs this to be sorted but who? - boost::range::sort(info->global_variables, MC_compare_variable); - - for (simgrid::mc::Variable& variable : info->global_variables) - if (variable.type_id) - variable.type = simgrid::util::find_map_ptr(info->types, variable.type_id); -} - -static void mc_post_process_scope(simgrid::mc::ObjectInformation* info, simgrid::mc::Frame* scope) -{ - if (scope->tag == DW_TAG_inlined_subroutine) { - // Attach correct namespaced name in inlined subroutine: - auto i = info->subprograms.find(scope->abstract_origin_id); - xbt_assert(i != info->subprograms.end(), "Could not lookup abstract origin %" PRIx64, - (std::uint64_t)scope->abstract_origin_id); - scope->name = i->second.name; - } - - // Direct: - for (simgrid::mc::Variable& variable : scope->variables) - if (variable.type_id) - variable.type = simgrid::util::find_map_ptr(info->types, variable.type_id); - - // Recursive post-processing of nested-scopes: - for (simgrid::mc::Frame& nested_scope : scope->scopes) - mc_post_process_scope(info, &nested_scope); -} - -static simgrid::mc::Type* MC_resolve_type(simgrid::mc::ObjectInformation* info, unsigned type_id) -{ - if (not type_id) - return nullptr; - simgrid::mc::Type* type = simgrid::util::find_map_ptr(info->types, type_id); - if (type == nullptr) - return nullptr; - - // We already have the information on the type: - if (type->byte_size != 0) - return type; - - // Don't have a name, we can't find a more complete version: - if (type->name.empty()) - return type; - - // Try to find a more complete description of the type: - // We need to fix in order to support C++. - if (simgrid::mc::Type** subtype = simgrid::util::find_map_ptr(info->full_types_by_name, type->name)) - type = *subtype; - return type; -} - -static void MC_post_process_types(simgrid::mc::ObjectInformation* info) -{ - // Lookup "subtype" field: - for (auto& [_, i] : info->types) { - i.subtype = MC_resolve_type(info, i.type_id); - for (simgrid::mc::Member& member : i.members) - member.type = MC_resolve_type(info, member.type_id); - } -} - -namespace simgrid::mc { - -void ObjectInformation::ensure_dwarf_loaded() -{ - if (dwarf_loaded) - return; - dwarf_loaded = true; - - MC_load_dwarf(this); - MC_post_process_variables(this); - MC_post_process_types(this); - for (auto& [_, entry] : this->subprograms) - mc_post_process_scope(this, &entry); - MC_make_functions_index(this); -} - -/** @brief Finds information about a given shared object/executable */ -std::shared_ptr createObjectInformation(std::vector const& maps, const char* name) -{ - auto result = std::make_shared(); - result->file_name = name; - simgrid::mc::find_object_address(maps, result.get()); - return result; -} - -/*************************************************************************/ - -void postProcessObjectInformation(const RemoteProcess* process, ObjectInformation* info) -{ - for (auto& [_, t] : info->types) { - Type* type = &t; - Type* subtype = type; - while (subtype->type == DW_TAG_typedef || subtype->type == DW_TAG_volatile_type || - subtype->type == DW_TAG_const_type) - if (subtype->subtype) - subtype = subtype->subtype; - else - break; - - // Resolve full_type: - if (not subtype->name.empty() && subtype->byte_size == 0) - for (auto const& object_info : process->object_infos) { - auto i = object_info->full_types_by_name.find(subtype->name); - if (i != object_info->full_types_by_name.end() && not i->second->name.empty() && i->second->byte_size) { - type->full_type = i->second; - break; - } - } - else - type->full_type = subtype; - } -} - -} // namespace simgrid::mc - -namespace simgrid::dwarf { - -/** Convert a DWARF register into a libunwind register - * - * DWARF and libunwind does not use the same convention for numbering the - * registers on some architectures. The function makes the necessary - * conversion. - */ -int dwarf_register_to_libunwind(int dwarf_register) -{ -#if defined(__x86_64__) || defined(__aarch64__) - // It seems for this arch, DWARF and libunwind agree in the numbering: - return dwarf_register; -#elif defined(__i386__) - // Couldn't find the authoritative source of information for this. - // This is inspired from http://source.winehq.org/source/dlls/dbghelp/cpu_i386.c#L517. - constexpr std::array regs{ - {/* 0 */ UNW_X86_EAX, /* 1 */ UNW_X86_ECX, /* 2 */ UNW_X86_EDX, /* 3 */ UNW_X86_EBX, - /* 4 */ UNW_X86_ESP, /* 5 */ UNW_X86_EBP, /* 6 */ UNW_X86_ESI, /* 7 */ UNW_X86_EDI, - /* 8 */ UNW_X86_EIP, /* 9 */ UNW_X86_EFLAGS, /* 10 */ UNW_X86_CS, /* 11 */ UNW_X86_SS, - /* 12 */ UNW_X86_DS, /* 13 */ UNW_X86_ES, /* 14 */ UNW_X86_FS, /* 15 */ UNW_X86_GS, - /* 16 */ UNW_X86_ST0, /* 17 */ UNW_X86_ST1, /* 18 */ UNW_X86_ST2, /* 19 */ UNW_X86_ST3, - /* 20 */ UNW_X86_ST4, /* 21 */ UNW_X86_ST5, /* 22 */ UNW_X86_ST6, /* 23 */ UNW_X86_ST7}}; - return regs.at(dwarf_register); -#else -#error This architecture is not supported yet for DWARF expression evaluation. -#endif -} - -} // namespace simgrid::dwarf