X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/598328397729daa2c9b18d353ec8570d99eedbcc..872d65264714799b25eb231609c3f05bae3d03dc:/src/mc/mc_dwarf.cpp diff --git a/src/mc/mc_dwarf.cpp b/src/mc/mc_dwarf.cpp index a9017d408c..30b5f38400 100644 --- a/src/mc/mc_dwarf.cpp +++ b/src/mc/mc_dwarf.cpp @@ -9,18 +9,21 @@ #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 "src/mc/mc_object_info.h" #include "src/mc/mc_private.h" #include "src/mc/mc_dwarf.hpp" @@ -100,7 +103,7 @@ static void MC_dwarf_handle_variable_die(simgrid::mc::ObjectInformation* info, D /** \brief Get the DW_TAG_type of the DIE * * \param die DIE - * \return DW_TAG_type attribute as a new string (NULL if none) + * \return DW_TAG_type attribute as a new string (nullptr if none) */ static std::uint64_t MC_dwarf_at_type(Dwarf_Die * die); @@ -257,11 +260,10 @@ static const char *MC_dwarf_attr_integrate_string(Dwarf_Die * die, int attribute) { Dwarf_Attribute attr; - if (!dwarf_attr_integrate(die, attribute, &attr)) { - return NULL; - } else { + if (!dwarf_attr_integrate(die, attribute, &attr)) + return nullptr; + else return dwarf_formstring(&attr); - } } /** \brief Get the linkage name of a DIE. @@ -272,7 +274,7 @@ static const char *MC_dwarf_attr_integrate_string(Dwarf_Die * die, * DW_AT_MIPS_linkage_name is used (at least by GCC). * * \param the DIE - * \return linkage name of the given DIE (or NULL) + * \return linkage name of the given DIE (or nullptr) * */ static const char *MC_dwarf_at_linkage_name(Dwarf_Die * die) { @@ -289,7 +291,7 @@ static Dwarf_Off MC_dwarf_attr_dieoffset(Dwarf_Die * die, int attribute) return 0; dwarf_attr_integrate(die, attribute, &attr); Dwarf_Die subtype_die; - if (dwarf_formref_die(&attr, &subtype_die) == NULL) + if (dwarf_formref_die(&attr, &subtype_die) == nullptr) xbt_die("Could not find DIE"); return dwarf_dieoffset(&subtype_die); } @@ -302,7 +304,7 @@ static Dwarf_Off MC_dwarf_attr_integrate_dieoffset(Dwarf_Die * die, return 0; dwarf_attr_integrate(die, DW_AT_type, &attr); Dwarf_Die subtype_die; - if (dwarf_formref_die(&attr, &subtype_die) == NULL) + if (dwarf_formref_die(&attr, &subtype_die) == nullptr) xbt_die("Could not find DIE"); return dwarf_dieoffset(&subtype_die); } @@ -310,7 +312,7 @@ static Dwarf_Off MC_dwarf_attr_integrate_dieoffset(Dwarf_Die * 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 NULL) + * \return DW_AT_type reference as a global offset in hexadecimal (or nullptr) */ static std::uint64_t MC_dwarf_at_type(Dwarf_Die * die) @@ -321,7 +323,7 @@ std::uint64_t MC_dwarf_at_type(Dwarf_Die * die) static uint64_t MC_dwarf_attr_integrate_addr(Dwarf_Die * die, int attribute) { Dwarf_Attribute attr; - if (dwarf_attr_integrate(die, attribute, &attr) == NULL) + if (dwarf_attr_integrate(die, attribute, &attr) == nullptr) return 0; Dwarf_Addr value; if (dwarf_formaddr(&attr, &value) == 0) @@ -334,7 +336,7 @@ 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) == NULL) + if (dwarf_attr_integrate(die, attribute, &attr) == nullptr) return default_value; Dwarf_Word value; return dwarf_formudata(dwarf_attr_integrate(die, attribute, &attr), @@ -571,11 +573,35 @@ static void MC_dwarf_add_members(simgrid::mc::ObjectInformation* info, Dwarf_Die // 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; + 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$ClassName", "__vptr.ClassName"): + if (boost::algorithm::starts_with(member.name, "__vptr$") || + boost::algorithm::starts_with(member.name, "__vptr.")) + member.flags |= simgrid::mc::Member::VIRTUAL_POINTER_FLAG; + // A cleaner stolution 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); @@ -631,7 +657,7 @@ static simgrid::mc::Type MC_dwarf_die_to_type( } const char *name = MC_dwarf_attr_integrate_string(die, DW_AT_name); - if (name != NULL) { + 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); @@ -666,21 +692,20 @@ static simgrid::mc::Type MC_dwarf_die_to_type( case DW_TAG_pointer_type: case DW_TAG_reference_type: case DW_TAG_rvalue_reference_type: - type.is_pointer_type = 1; 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 == NULL ? xbt_strdup(type.name.c_str()) + 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); + return type; } static void MC_dwarf_handle_type_die(simgrid::mc::ObjectInformation* info, Dwarf_Die * die, @@ -709,14 +734,14 @@ static std::unique_ptr MC_die_to_variable( return nullptr; Dwarf_Attribute attr_location; - if (dwarf_attr(die, DW_AT_location, &attr_location) == NULL) + 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 == NULL; // Can be override base on DW_AT_location + 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); @@ -741,12 +766,12 @@ static std::unique_ptr MC_die_to_variable( xbt_die( "Could not read location expression in DW_AT_location " "of variable <%" PRIx64 ">%s", - (uint64_t) variable->dwarf_offset, + (uint64_t) variable->id, variable->name.c_str()); } if (len == 1 && expr[0].atom == DW_OP_addr) { - variable->global = 1; + variable->global = true; uintptr_t offset = (uintptr_t) expr[0].number; uintptr_t base = (uintptr_t) info->base_address(); variable->address = (void *) (base + offset); @@ -768,7 +793,7 @@ static std::unique_ptr MC_die_to_variable( 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, + (uint64_t) variable->id, variable->name.c_str()); } @@ -791,7 +816,7 @@ static std::unique_ptr MC_die_to_variable( default: xbt_die ("Unhandled form 0x%x, class 0x%X for DW_AT_start_scope of variable %s", - form, (int) form_class, name == NULL ? "?" : name); + form, (int) form_class, name == nullptr ? "?" : name); } } @@ -805,7 +830,7 @@ static std::unique_ptr MC_die_to_variable( variable->name = "@anonymous#" + std::to_string(mc_anonymous_variable_index++); - return std::move(variable); + return variable; } static void MC_dwarf_handle_variable_die(simgrid::mc::ObjectInformation* info, Dwarf_Die * die, @@ -868,9 +893,8 @@ static void MC_dwarf_handle_scope_die(simgrid::mc::ObjectInformation* info, Dwar if (low_pc) { // DW_AT_high_pc: Dwarf_Attribute attr; - if (!dwarf_attr_integrate(die, DW_AT_high_pc, &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; @@ -889,7 +913,7 @@ static void MC_dwarf_handle_scope_die(simgrid::mc::ObjectInformation* info, Dwar case simgrid::dwarf::FormClass::Address: if (dwarf_formaddr(&attr, &high_pc) != 0) xbt_die("Could not read address"); - frame.range.begin() = base + high_pc; + frame.range.end() = base + high_pc; break; default: @@ -928,7 +952,7 @@ static void mc_dwarf_handle_namespace_die(simgrid::mc::ObjectInformation* info, 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 == NULL ? xbt_strdup(name) + 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); @@ -942,9 +966,8 @@ static void MC_dwarf_handle_children(simgrid::mc::ObjectInformation* info, Dwarf Dwarf_Die child; int res; for (res = dwarf_child(die, &child); res == 0; - res = dwarf_siblingof(&child, &child)) { + 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, @@ -982,9 +1005,8 @@ static void MC_dwarf_handle_die(simgrid::mc::ObjectInformation* info, Dwarf_Die } static -Elf64_Half MC_dwarf_elf_type(Dwarf* dwarf) +Elf64_Half get_type(Elf* elf) { - Elf* elf = dwarf_getelf(dwarf); Elf64_Ehdr* ehdr64 = elf64_getehdr(elf); if (ehdr64) return ehdr64->e_type; @@ -994,6 +1016,134 @@ Elf64_Half MC_dwarf_elf_type(Dwarf* dwarf) 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) { + Dwarf_Die unit_die; + if (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) +{ + 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 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 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 @@ -1002,35 +1152,75 @@ Elf64_Half MC_dwarf_elf_type(Dwarf* dwarf) 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()); - Dwarf *dwarf = dwarf_begin(fd, DWARF_C_READ); - if (dwarf == NULL) - xbt_die("Missing debugging information in %s\n" - "Your program and its dependencies must have debugging information.\n" - "You might want to recompile with -g or install the suitable debugging package.\n", - info->file_name.c_str()); - - Elf64_Half elf_type = MC_dwarf_elf_type(dwarf); - if (elf_type == ET_EXEC) + 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; - // For each compilation unit: - Dwarf_Off offset = 0; - Dwarf_Off next_offset = 0; - size_t length; + // 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); - while (dwarf_nextcu(dwarf, offset, &next_offset, &length, NULL, NULL, NULL) == - 0) { - Dwarf_Die unit_die; - if (dwarf_offdie(dwarf, offset + length, &unit_die) != NULL) - MC_dwarf_handle_children(info, &unit_die, &unit_die, NULL, NULL); - offset = next_offset; + // 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; } - dwarf_end(dwarf); - close(fd); + // 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 @@ -1143,8 +1333,11 @@ static void MC_post_process_types(simgrid::mc::ObjectInformation* info) } } +namespace simgrid { +namespace mc { + /** \brief Finds informations about a given shared object/executable */ -std::shared_ptr MC_find_object_info( +std::shared_ptr createObjectInformation( std::vector const& maps, const char *name) { std::shared_ptr result = @@ -1157,12 +1350,12 @@ std::shared_ptr MC_find_object_info( for (auto& entry : result.get()->subprograms) mc_post_process_scope(result.get(), &entry.second); MC_make_functions_index(result.get()); - return std::move(result); + return result; } /*************************************************************************/ -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) { @@ -1177,7 +1370,7 @@ 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() @@ -1186,11 +1379,14 @@ 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 {