X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/be7aebfeb78fec388f583585aa207a6fe85df69a..30d60b272963b1b130ea80840af783ee9c146b97:/src/mc/mc_dwarf.cpp diff --git a/src/mc/mc_dwarf.cpp b/src/mc/mc_dwarf.cpp index d3a6f4f100..7942ae22b3 100644 --- a/src/mc/mc_dwarf.cpp +++ b/src/mc/mc_dwarf.cpp @@ -9,26 +9,1194 @@ #include #include +#include -#include +#include +#include #define DW_LANG_Objc DW_LANG_ObjC /* fix spelling error in older dwarf.h */ +#include +#include -#include +#include +#include "src/simgrid/util.hpp" #include #include -#include +#include "src/mc/mc_private.h" +#include "src/mc/mc_dwarf.hpp" -#include "mc/mc_dwarf.hpp" -#include "mc/mc_dwarf.hpp" -#include "mc/mc_private.h" -#include "mc/mc_process.h" - -#include "mc/ObjectInformation.hpp" -#include "mc/Variable.hpp" +#include "src/mc/Process.hpp" +#include "src/mc/ObjectInformation.hpp" +#include "src/mc/Variable.hpp" 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 consant 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 fot the library/binary file (output) + * \param die the current DIE + * \param unit the DIE of the compile unit of the current DIE + * \param frame containg 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 childrend of the given die + * + * \param info the resulting object fot the library/binary file (output) + * \param die the current DIE + * \param unit the DIE of the compile unit of the current DIE + * \param frame containg 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 fot the library/binary file (output) + * \param die the current DIE + * \param unit the DIE of the compile unit of the current DIE + * \param frame containg frame if any + */ +static void MC_dwarf_handle_variable_die(simgrid::mc::ObjectInformation* info, Dwarf_Die * die, + 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 { +namespace 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) +{ + switch (tag) { + + case DW_TAG_array_type: + case DW_TAG_class_type: + case DW_TAG_enumeration_type: + case DW_TAG_typedef: + case DW_TAG_pointer_type: + case DW_TAG_reference_type: + case DW_TAG_rvalue_reference_type: + case DW_TAG_string_type: + case DW_TAG_structure_type: + case DW_TAG_subroutine_type: + case DW_TAG_union_type: + case DW_TAG_ptr_to_member_type: + case DW_TAG_set_type: + case DW_TAG_subrange_type: + case DW_TAG_base_type: + case DW_TAG_const_type: + case DW_TAG_file_type: + case DW_TAG_packed_type: + case DW_TAG_volatile_type: + case DW_TAG_restrict_type: + case DW_TAG_interface_type: + case DW_TAG_unspecified_type: + case DW_TAG_shared_type: + return TagClass::Type; + + case DW_TAG_subprogram: + return TagClass::Subprogram; + + case DW_TAG_variable: + case DW_TAG_formal_parameter: + return TagClass::Variable; + + case DW_TAG_lexical_block: + case DW_TAG_try_block: + case DW_TAG_catch_block: + case DW_TAG_inlined_subroutine: + case DW_TAG_with_stmt: + return TagClass::Scope; + + case DW_TAG_namespace: + return TagClass::Namespace; + + default: + return 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) +{ + switch (form) { + case DW_FORM_addr: + return FormClass::Address; + case DW_FORM_block2: + case DW_FORM_block4: + case DW_FORM_block: + case DW_FORM_block1: + return FormClass::Block; + case DW_FORM_data1: + case DW_FORM_data2: + case DW_FORM_data4: + case DW_FORM_data8: + case DW_FORM_udata: + case DW_FORM_sdata: + return FormClass::Constant; + case DW_FORM_string: + case DW_FORM_strp: + return FormClass::String; + case DW_FORM_ref_addr: + case DW_FORM_ref1: + case DW_FORM_ref2: + case DW_FORM_ref4: + case DW_FORM_ref8: + case DW_FORM_ref_udata: + return FormClass::Reference; + case DW_FORM_flag: + case DW_FORM_flag_present: + return FormClass::Flag; + case DW_FORM_exprloc: + return FormClass::ExprLoc; + // TODO sec offset + // TODO indirect + default: + return 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 simgrid::dwarf::tagname(dwarf_tag(die)); +} + +} +} + +// ***** 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 (!dwarf_attr_integrate(die, attribute, &attr)) + return nullptr; + else + return dwarf_formstring(&attr); +} + +/** \brief Get the linkage name of a DIE. + * + * Use either DW_AT_linkage_name or DW_AT_MIPS_linkage_name. + * DW_AT_linkage_name is standardized since DWARF 4. + * Before this version of DWARF, the MIPS extensions + * DW_AT_MIPS_linkage_name is used (at least by GCC). + * + * \param the DIE + * \return linkage name of the given DIE (or nullptr) + * */ +static const char *MC_dwarf_at_linkage_name(Dwarf_Die * die) +{ + const char *name = MC_dwarf_attr_integrate_string(die, DW_AT_linkage_name); + if (!name) + name = MC_dwarf_attr_integrate_string(die, DW_AT_MIPS_linkage_name); + return name; +} + +static Dwarf_Off MC_dwarf_attr_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; + if (dwarf_formref_die(&attr, &subtype_die) == nullptr) + xbt_die("Could not find DIE"); + return dwarf_dieoffset(&subtype_die); +} + +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, DW_AT_type, &attr); + Dwarf_Die subtype_die; + if (dwarf_formref_die(&attr, &subtype_die) == nullptr) + xbt_die("Could not find DIE"); + return dwarf_dieoffset(&subtype_die); +} + +/** \brief Find the type/subtype (DW_AT_type) for a DIE + * + * \param dit 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)) == 0) + return false; + + bool result; + if (dwarf_formflag(&attr, &result)) + xbt_die("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) +{ + switch (lang) { + case DW_LANG_C: + case DW_LANG_C89: + case DW_LANG_C99: + case DW_LANG_C_plus_plus: + case DW_LANG_D: + case DW_LANG_Java: + case DW_LANG_ObjC: + case DW_LANG_ObjC_plus_plus: + case DW_LANG_Python: + case DW_LANG_UPC: + return 0; + case DW_LANG_Ada83: + case DW_LANG_Ada95: + case DW_LANG_Fortran77: + case DW_LANG_Fortran90: + case DW_LANG_Fortran95: + case DW_LANG_Modula2: + case DW_LANG_Pascal83: + case DW_LANG_PL1: + case DW_LANG_Cobol74: + case DW_LANG_Cobol85: + return 1; + default: + xbt_die("No default DW_TAG_lower_bound for language %i and none given", + lang); + return 0; + } +} + +/** \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 (!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, -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, -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 a 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; + int res; + for (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 = strcmp(a.name.c_str(), b.name.c_str()); + 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( + simgrid::mc::Type* type, simgrid::mc::Member* member, Dwarf_Die * child) +{ + if (dwarf_hasattr(child, DW_AT_data_bit_offset)) + xbt_die("Can't groke DW_AT_data_bit_offset."); + + if (!dwarf_hasattr_integrate(child, DW_AT_data_member_location)) { + if (type->type == DW_TAG_union_type) + return; + xbt_die + ("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()); + } + + 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; + if (dwarf_getlocation(&attr, &expr, &len)) + xbt_die + ("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; + if (!dwarf_formudata(&attr, &offset)) + member->offset(offset); + else + xbt_die("Cannot get %s location <%" PRIx64 ">%s", + MC_dwarf_attr_integrate_string(child, DW_AT_name), + (uint64_t) type->id, type->name.c_str()); + break; + } + case simgrid::dwarf::FormClass::LocListPtr: + // Reference to a location list: + // TODO + case simgrid::dwarf::FormClass::Reference: + // It's supposed to be possible in DWARF2 but I couldn't find its semantic + // in the spec. + default: + xbt_die("Can't handle form class (%i) / form 0x%x as DW_AT_member_location", + (int) form_class, 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(simgrid::mc::ObjectInformation* info, Dwarf_Die * die, + Dwarf_Die * unit, simgrid::mc::Type* type) +{ + int res; + Dwarf_Die child; + xbt_assert(type->members.empty()); + for (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; + member.inheritance = tag == DW_TAG_inheritance; + + const char *name = MC_dwarf_attr_integrate_string(&child, DW_AT_name); + if (name) + member.name = name; + 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_die("Can't groke DW_AT_data_bit_offset."); + + MC_dwarf_fill_member_location(type, &member, &child); + + if (!member.type_id) + xbt_die("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 (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) { + char* full_name = ns ? bprintf("%s%s::%s", prefix, ns, name) : + bprintf("%s%s", prefix, name); + type.name = std::string(full_name); + free(full_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); + char *new_ns = ns == nullptr ? xbt_strdup(type.name.c_str()) + : bprintf("%s::%s", ns, name); + MC_dwarf_handle_children(info, die, unit, frame, new_ns); + free(new_ns); + break; + } + + return std::move(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 (!t.name.empty() && type.byte_size != 0) + info->full_types_by_name[t.name] = &t; +} + +static int mc_anonymous_variable_index = 0; + +static std::unique_ptr MC_die_to_variable( + simgrid::mc::ObjectInformation* info, Dwarf_Die * die, + Dwarf_Die * unit, 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; + + std::unique_ptr variable = + std::unique_ptr(new simgrid::mc::Variable()); + variable->dwarf_offset = 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; + if (dwarf_getlocation(&attr_location, &expr, &len)) { + xbt_die( + "Could not read location expression in DW_AT_location " + "of variable <%" PRIx64 ">%s", + (uint64_t) variable->dwarf_offset, + variable->name.c_str()); + } + + if (len == 1 && expr[0].atom == DW_OP_addr) { + variable->global = 1; + uintptr_t offset = (uintptr_t) expr[0].number; + uintptr_t base = (uintptr_t) info->base_address(); + variable->address = (void *) (base + offset); + } else + variable->location_list = { + 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", + form, form, (int) form_class, (int) form_class, + (uint64_t) variable->dwarf_offset, + 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); + int form = dwarf_whatform(&attr); + simgrid::dwarf::FormClass form_class = simgrid::dwarf::classify_form(form); + switch (form_class) { + case simgrid::dwarf::FormClass::Constant: + { + Dwarf_Word value; + variable->start_scope = + dwarf_formudata(&attr, &value) == 0 ? (size_t) value : 0; + break; + } + + case simgrid::dwarf::FormClass::RangeListPtr: // TODO + default: + xbt_die + ("Unhandled form 0x%x, class 0x%X for DW_AT_start_scope of variable %s", + form, (int) 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: + if (variable->name.empty()) + variable->name = + "@anonymous#" + std::to_string(mc_anonymous_variable_index++); + + return std::move(variable); +} + +static void MC_dwarf_handle_variable_die(simgrid::mc::ObjectInformation* info, Dwarf_Die * die, + Dwarf_Die * unit, simgrid::mc::Frame* frame, + const char *ns) +{ + std::unique_ptr variable = + MC_die_to_variable(info, die, unit, frame, ns); + if (!variable) + return; + // Those arrays are sorted later: + else 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 (ns) + frame.name = std::string(ns) + "::" + name; + else if (name) + frame.name = name; + } + + frame.abstract_origin_id = + MC_dwarf_attr_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 + std::uint64_t base = (std::uint64_t) 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 ? (std::uint64_t) base + low_pc : 0; + if (low_pc) { + // DW_AT_high_pc: + Dwarf_Attribute attr; + if (!dwarf_attr_integrate(die, DW_AT_high_pc, &attr)) + xbt_die("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: + + if (dwarf_formsdata(&attr, &offset) != 0) + xbt_die("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: + if (dwarf_formaddr(&attr, &high_pc) != 0) + xbt_die("Could not read address"); + frame.range.begin() = 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: + std::sort(frame.variables.begin(), frame.variables.end(), + 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); + if (frame) + xbt_die("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; + int res; + for (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) +{ + Elf64_Ehdr* ehdr64 = elf64_getehdr(elf); + if (ehdr64) + return ehdr64->e_type; + Elf32_Ehdr* ehdr32 = elf32_getehdr(elf); + if (ehdr32) + 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, NULL, NULL) == + 0) { + Dwarf_Die unit_die; + if (dwarf_offdie(dwarf, offset + length, &unit_die) != nullptr) + MC_dwarf_handle_children(info, &unit_die, &unit_die, nullptr, NULL); + 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) +{ + size_t phnum; + if (elf_getphdrnum (elf, &phnum) != 0) + xbt_die("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; + 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 (1) { + GElf_Nhdr nhdr; + size_t name_pos; + size_t desc_pos; + pos = gelf_getnote(data, pos, &nhdr, &name_pos, &desc_pos); + // A note is identified by a name "GNU" and a integer type within + // the namespace defined by this name (here NT_GNU_BUILD_ID): + if (nhdr.n_type == NT_GNU_BUILD_ID + && nhdr.n_namesz == sizeof("GNU") + && memcmp((char*) data->d_buf + name_pos, "GNU", sizeof("GNU")) == 0) { + + // Found the NT_GNU_BUILD_ID note: + char* start = (char*) data->d_buf + desc_pos; + char* end = (char*) start + nhdr.n_descsz; + return std::vector(start, end); + + } + } + + } + return std::vector(); +} + +static char hexdigits[16] = { + '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', + 'a', 'b', 'c', 'd', 'e', 'f' +}; + +/** Binary data to hexadecimal */ +static inline +std::array to_hex(std::uint8_t byte) +{ + // 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::array hex_byte = to_hex(data[i]); + for (int j = 0; j < 2; ++j) + res[2 * i + j] = hex_byte[j]; + } + return std::move(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 +const char* 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). + */ +static +std::string find_by_build_id(std::vector id) +{ + std::string filename; + for (const char* debug_path : debug_paths) { + filename = debug_path; + filename += ".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 (access(filename.c_str(), F_OK) == 0) + return std::move(filename); + } + return std::string(); +} + +/** \brief Populate the debugging informations of the given ELF object + * + * Read the DWARf information of the EFFL object and populate the + * lists of types, variables, functions. + */ +static +void MC_dwarf_get_variables(simgrid::mc::ObjectInformation* info) +{ + if (elf_version(EV_CURRENT) == EV_NONE) + xbt_die("libelf initialization error"); + + // Open the ELF file: + int fd = open(info->file_name.c_str(), O_RDONLY); + if (fd < 0) + xbt_die("Could not open file %s", info->file_name.c_str()); + Elf* elf = elf_begin(fd, ELF_C_READ, nullptr); + if (elf == nullptr) + xbt_die("Not an ELF file 1"); + Elf_Kind kind = elf_kind(elf); + if (kind != ELF_K_ELF) + xbt_die("Not an ELF file 2"); + + // Remember if this is a `ET_EXEC` (fixed location) or `ET_DYN` (relocatable): + Elf64_Half type = get_type(elf); + if (type == ET_EXEC) + info->flags |= simgrid::mc::ObjectInformation::Executable; + + // Read DWARF debug information in the file: + Dwarf* dwarf = dwarf_begin_elf (elf, DWARF_C_READ, nullptr); + if (dwarf != nullptr) { + read_dwarf_info(info, dwarf); + dwarf_end(dwarf); + elf_end(elf); + close(fd); + return; + } + dwarf_end(dwarf); + + // If there was no DWARF in the file, try to find it in a separate file + // with NT_GNU_BUILD_ID: + std::vector build_id = get_build_id(elf); + if (!build_id.empty()) { + elf_end(elf); + close(fd); + + // Find the debug file using the build id: + std::string debug_file = find_by_build_id(build_id); + if (debug_file.empty()) { + std::string hex = to_hex(build_id); + xbt_die( + "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(), hex.c_str()); + } + + // Load the DWARF info from this file: + XBT_DEBUG("Load DWARF for %s from %s", + info->file_name.c_str(), debug_file.c_str()); + fd = open(debug_file.c_str(), O_RDONLY); + if (fd < 0) + xbt_die("Could not open file %s", debug_file.c_str()); + Dwarf* dwarf = dwarf_begin(fd, DWARF_C_READ); + if (dwarf == nullptr) + xbt_die("No DWARF info in %s for %s", + debug_file.c_str(), info->file_name.c_str()); + read_dwarf_info(info, dwarf); + dwarf_end(dwarf); + close(fd); + return; + } + + // TODO, try to find DWARF info using debug-link. + // Is this method really used anywhere? + + xbt_die("Debugging information not found for %s\n" + "Try recompiling with -g\n", + info->file_name.c_str()); +} + // ***** Functions index static int MC_compare_frame_index_items(simgrid::mc::FunctionIndexEntry* a, @@ -47,10 +1215,10 @@ static void MC_make_functions_index(simgrid::mc::ObjectInformation* info) info->functions_index.clear(); for (auto& e : info->subprograms) { - if (e.second.low_pc == nullptr) + if (e.second.range.begin() == 0) continue; simgrid::mc::FunctionIndexEntry entry; - entry.low_pc = e.second.low_pc; + entry.low_pc = (void*) e.second.range.begin(); entry.function = &e.second; info->functions_index.push_back(entry); } @@ -78,8 +1246,7 @@ static void MC_post_process_variables(simgrid::mc::ObjectInformation* info) info->types, variable.type_id); } -static void mc_post_process_scope( - simgrid::mc::ObjectInformation* info, simgrid::mc::Frame* scope) +static void mc_post_process_scope(simgrid::mc::ObjectInformation* info, simgrid::mc::Frame* scope) { if (scope->tag == DW_TAG_inlined_subroutine) { @@ -103,48 +1270,54 @@ static void mc_post_process_scope( } -/** \brief Fill/lookup the "subtype" field. - */ -static void MC_resolve_subtype( - simgrid::mc::ObjectInformation* info, simgrid::mc::Type* type) +static +simgrid::mc::Type* MC_resolve_type( + simgrid::mc::ObjectInformation* info, unsigned type_id) { - if (!type->type_id) - return; - type->subtype = simgrid::util::find_map_ptr(info->types, type->type_id); - if (type->subtype == nullptr) - return; - if (type->subtype->byte_size != 0) - return; - if (type->subtype->name.empty()) - return; + if (!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++. simgrid::mc::Type** subtype = simgrid::util::find_map_ptr( - info->full_types_by_name, type->subtype->name); + info->full_types_by_name, type->name); if (subtype) - type->subtype = *subtype; + type = *subtype; + return type; } static void MC_post_process_types(simgrid::mc::ObjectInformation* info) { // Lookup "subtype" field: for(auto& i : info->types) { - MC_resolve_subtype(info, &(i.second)); - for (simgrid::mc::Type& member : i.second.members) - MC_resolve_subtype(info, &member); + i.second.subtype = MC_resolve_type(info, i.second.type_id); + for (simgrid::mc::Member& member : i.second.members) + member.type = MC_resolve_type(info, member.type_id); } } +namespace simgrid { +namespace mc { + /** \brief Finds informations about a given shared object/executable */ -std::shared_ptr MC_find_object_info( - std::vector const& maps, const char *name, int executable) +std::shared_ptr createObjectInformation( + std::vector const& maps, const char *name) { std::shared_ptr result = std::make_shared(); - if (executable) - result->flags |= simgrid::mc::ObjectInformation::Executable; result->file_name = name; - MC_find_object_address(maps, result.get()); + simgrid::mc::find_object_address(maps, result.get()); MC_dwarf_get_variables(result.get()); MC_post_process_variables(result.get()); MC_post_process_types(result.get()); @@ -156,7 +1329,7 @@ std::shared_ptr MC_find_object_info( /*************************************************************************/ -void MC_post_process_object_info(simgrid::mc::Process* process, simgrid::mc::ObjectInformation* info) +void postProcessObjectInformation(simgrid::mc::Process* process, simgrid::mc::ObjectInformation* info) { for (auto& i : info->types) { @@ -171,7 +1344,7 @@ void MC_post_process_object_info(simgrid::mc::Process* process, simgrid::mc::Obj break; // Resolve full_type: - if (!subtype->name.empty() && subtype->byte_size == 0) { + if (!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() @@ -180,7 +1353,87 @@ void MC_post_process_object_info(simgrid::mc::Process* process, simgrid::mc::Obj break; } } - } else type->full_type = subtype; + else type->full_type = subtype; + + } +} +} +} + +namespace simgrid { +namespace 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 + * convertion. + */ +int dwarf_register_to_libunwind(int dwarf_register) +{ +#if defined(__x86_64__) + // It seems for this arch, DWARF and libunwind agree in the numbering: + return dwarf_register; +#elif defined(__i386__) + // Could't find the authoritative source of information for this. + // This is inspired from http://source.winehq.org/source/dlls/dbghelp/cpu_i386.c#L517. + switch (dwarf_register) { + case 0: + return UNW_X86_EAX; + case 1: + return UNW_X86_ECX; + case 2: + return UNW_X86_EDX; + case 3: + return UNW_X86_EBX; + case 4: + return UNW_X86_ESP; + case 5: + return UNW_X86_EBP; + case 6: + return UNW_X86_ESI; + case 7: + return UNW_X86_EDI; + case 8: + return UNW_X86_EIP; + case 9: + return UNW_X86_EFLAGS; + case 10: + return UNW_X86_CS; + case 11: + return UNW_X86_SS; + case 12: + return UNW_X86_DS; + case 13: + return UNW_X86_ES; + case 14: + return UNW_X86_FS; + case 15: + return UNW_X86_GS; + case 16: + return UNW_X86_ST0; + case 17: + return UNW_X86_ST1; + case 18: + return UNW_X86_ST2; + case 19: + return UNW_X86_ST3; + case 20: + return UNW_X86_ST4; + case 21: + return UNW_X86_ST5; + case 22: + return UNW_X86_ST6; + case 23: + return UNW_X86_ST7; + default: + xbt_die("Bad/unknown register number."); } +#else +#error This architecture is not supported yet for DWARF expression evaluation. +#endif +} + +} }