#include <algorithm>
#include <memory>
+#include <utility>
#include <cstdlib>
#define DW_LANG_Objc DW_LANG_ObjC /* fix spelling error in older dwarf.h */
#include <xbt/log.h>
#include <xbt/sysdep.h>
-#include "mc_object_info.h"
-#include "mc_private.h"
-#include "mc_dwarf.hpp"
+#include "src/mc/mc_private.h"
+#include "src/mc/mc_dwarf.hpp"
+#include "src/mc/mc_object_info.h"
#include "src/mc/Process.hpp"
#include "src/mc/ObjectInformation.hpp"
#include "src/mc/Variable.hpp"
/** \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);
RangeListPtr
};
-XBT_PRIVATE
+static
TagClass classify_tag(int tag)
{
switch (tag) {
* \param form The form (values taken from the DWARF spec)
* \return An internal representation for the corresponding class
* */
-XBT_PRIVATE
+static
FormClass classify_form(int form)
{
switch (form) {
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),
}
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);
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->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);
uintptr_t offset = (uintptr_t) expr[0].number;
uintptr_t base = (uintptr_t) info->base_address();
variable->address = (void *) (base + offset);
- } else {
- simgrid::dwarf::LocationListEntry entry;
- entry.expression = {expr, expr + len};
- variable->location_list = { std::move(entry) };
- }
+ } else
+ variable->location_list = {
+ simgrid::dwarf::DwarfExpression(expr, expr + len) };
break;
}
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);
}
}
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)
+ if (ns)
frame.name = std::string(ns) + "::" + name;
else if (name)
frame.name = name;
- else
- frame.name.clear();
}
frame.abstract_origin_id =
// This is the base address for DWARF addresses.
// Relocated addresses are offset from this base address.
// See DWARF4 spec 7.5
- void *base = info->base_address();
+ 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.low_pc = low_pc ? ((char *) base) + low_pc : 0;
+ 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)) {
+ 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;
if (dwarf_formsdata(&attr, &offset) != 0)
xbt_die("Could not read constant");
- frame.high_pc = (void *) ((char *) frame.low_pc + offset);
+ 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.high_pc = ((char *) base) + high_pc;
+ frame.range.begin() = base + high_pc;
break;
default:
// Handle children:
MC_dwarf_handle_children(info, die, unit, &frame, ns);
- // Someone needs this to be sorted but who?
+ // 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] = frame;
+ info->subprograms[frame.id] = std::move(frame);
else if (klass == simgrid::dwarf::TagClass::Scope)
parent_frame->scopes.push_back(std::move(frame));
}
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, 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
+ *
+ * Return an empty vector is none is found.
+ */
+static
+std::vector<char> get_build_id(Elf* elf)
+{
+ size_t phnum;
+ if (elf_getphdrnum (elf, &phnum) != 0)
+ xbt_die("Could not read program headers");
+ 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);
+ 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);
+ if (nhdr.n_type == NT_GNU_BUILD_ID
+ && nhdr.n_namesz == sizeof("GNU")
+ && memcmp((char*) data->d_buf + name_pos, "GNU", sizeof("GNU")) == 0) {
+ 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'
+};
+
+static inline
+std::array<char, 2> to_hex(std::uint8_t byte)
+{
+ return { hexdigits[byte >> 4], hexdigits[byte & 0xF] };
+}
+
+/** Hexadecimal representation of some binary data */
+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 std::move(res);
+}
+
+static
+std::string to_hex(std::vector<char> const& data)
+{
+ return to_hex(data.data(), data.size());
+}
+
+const char* debug_paths[] = {
+ "/usr/lib/debug/",
+ "/usr/local/lib/debug/"
+};
+
+static
+std::string find_by_build_id(std::vector<char> 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
static
void MC_dwarf_get_variables(simgrid::mc::ObjectInformation* info)
{
+ if (elf_version(EV_CURRENT) == EV_NONE)
+ xbt_die("libelf initialization error");
+
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");
+
+ 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;
+ Dwarf* dwarf = dwarf_begin_elf (elf, DWARF_C_READ, nullptr);
+ if (dwarf != nullptr) {
+ // This is the simple case where DWARF is located in the ELF file:
+ 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;
+ // Try to find it with NT_GNU_BUILD_ID:
+ std::vector<char> build_id = get_build_id(elf);
+ if (!build_id.empty()) {
+ elf_end(elf);
+ close(fd);
+
+ // Find a 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 debug-link actually used anywhere?
+
+ // Everything failes, complain loudly:
+ xbt_die("Debugging information not found for %s\n"
+ "Try recompiling with -g\n",
+ info->file_name.c_str());
}
// ***** Functions index
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);
}
std::shared_ptr<simgrid::mc::ObjectInformation> result =
std::make_shared<simgrid::mc::ObjectInformation>();
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());
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;
}
}
}
}
-}
\ No newline at end of file
+}
