#include <cinttypes>
#include <cstdint>
-#include <algorithm>
#include <memory>
+#include <utility>
+#include <boost/range/algorithm.hpp>
+
+#include <fcntl.h>
#include <cstdlib>
#define DW_LANG_Objc DW_LANG_ObjC /* fix spelling error in older dwarf.h */
#include <dwarf.h>
#include <elfutils/libdw.h>
+#include <boost/algorithm/string/predicate.hpp>
+
#include <simgrid_config.h>
#include "src/simgrid/util.hpp"
#include <xbt/log.h>
#include <xbt/sysdep.h>
-#include "src/mc/mc_object_info.h"
#include "src/mc/mc_private.h"
#include "src/mc/mc_dwarf.hpp"
*
* The default for a given language is defined in the DWARF spec.
*
- * \param language consant as defined by the DWARf spec
+ * \param language constant as defined by the DWARf spec
*/
static uint64_t MC_dwarf_default_lower_bound(int lang);
* \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
+ * \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,
Dwarf_Die * unit, simgrid::mc::Frame* frame,
const char *ns);
-/** \brief Calls MC_dwarf_handle_die on all childrend of the given die
+/** \brief Calls MC_dwarf_handle_die on all children 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
+ * \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,
* \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
+ * \param frame containing frame if any
*/
static void MC_dwarf_handle_variable_die(simgrid::mc::ObjectInformation* info, Dwarf_Die * die,
Dwarf_Die * unit, simgrid::mc::Frame* frame,
/** \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);
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.
* 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)
{
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);
}
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);
}
/** \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)
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)
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),
// 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 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);
}
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);
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,
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<simgrid::mc::Variable> variable =
std::unique_ptr<simgrid::mc::Variable>(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);
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);
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());
}
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);
}
}
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,
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;
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:
// We sort them in order to have an (somewhat) efficient by name
// lookup:
- std::sort(frame.variables.begin(), frame.variables.end(),
- MC_compare_variable);
+ boost::range::sort(frame.variables, MC_compare_variable);
// Register it:
if (klass == simgrid::dwarf::TagClass::Subprogram)
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);
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,
}
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;
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<char> get_build_id(Elf* elf)
+{
+ // 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;
+ 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 (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 = (char*) start + nhdr.n_descsz;
+ return std::vector<char>(start, end);
+ }
+ }
+
+ }
+ return std::vector<char>();
+}
+
+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<char, 2> 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<char, 2> 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<char> 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).
+ */
+// Example:
+// /usr/lib/debug/.build-id/0b/dc77f1c29aea2b14ff5acd9a19ab3175ffdeae.debug
+static
+std::string find_by_build_id(std::vector<char> id)
+{
+ std::string filename;
+ std::string hex = to_hex(id);
+ for (const char* 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 (access(filename.c_str(), F_OK) == 0) {
+ XBT_DEBUG("Found debug file: %s\n", hex.c_str());
+ return filename;
+ }
+ }
+ XBT_DEBUG("Not debuf info found for build ID %s\n", hex.data());
+ 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)
+void MC_load_dwarf(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");
+ Elf_Kind kind = elf_kind(elf);
+ if (kind != ELF_K_ELF)
+ xbt_die("Not an ELF file");
+
+ // Remember if this is a `ET_EXEC` (fixed location) or `ET_DYN`:
+ 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.
+ // Different methods might be used to store the DWARF informations:
+ // * 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.
+ std::vector<char> 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);
+ // 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
info->functions_index.shrink_to_fit();
// Sort the array by low_pc:
- std::sort(info->functions_index.begin(), info->functions_index.end(),
+ boost::range::sort(info->functions_index,
[](simgrid::mc::FunctionIndexEntry const& a,
simgrid::mc::FunctionIndexEntry const& b)
{
static void MC_post_process_variables(simgrid::mc::ObjectInformation* info)
{
// Someone needs this to be sorted but who?
- std::sort(info->global_variables.begin(), info->global_variables.end(),
- MC_compare_variable);
+ boost::range::sort(info->global_variables, MC_compare_variable);
for(simgrid::mc::Variable& variable : info->global_variables)
if (variable.type_id)
}
}
+namespace simgrid {
+namespace mc {
+
/** \brief Finds informations about a given shared object/executable */
-std::shared_ptr<simgrid::mc::ObjectInformation> MC_find_object_info(
+std::shared_ptr<simgrid::mc::ObjectInformation> createObjectInformation(
std::vector<simgrid::xbt::VmMap> const& maps, const char *name)
{
std::shared_ptr<simgrid::mc::ObjectInformation> result =
std::make_shared<simgrid::mc::ObjectInformation>();
result->file_name = name;
- MC_find_object_address(maps, result.get());
- MC_dwarf_get_variables(result.get());
+ simgrid::mc::find_object_address(maps, result.get());
+ MC_load_dwarf(result.get());
MC_post_process_variables(result.get());
MC_post_process_types(result.get());
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) {
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()
break;
}
}
- } else type->full_type = subtype;
+ else type->full_type = subtype;
}
}
+}
+}
+
namespace simgrid {
namespace dwarf {
*
* DWARF and libunwind does not use the same convention for numbering the
* registers on some architectures. The function makes the necessary
- * convertion.
+ * conversion.
*/
int dwarf_register_to_libunwind(int dwarf_register)
{
// 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.
+ // 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.
switch (dwarf_register) {
case 0:
