[mc] Reorganise the ELF/DWARF processing

[simgrid.git] / src / mc / mc_dwarf.cpp

diff --git a/src/mc/mc_dwarf.cpp b/src/mc/mc_dwarf.cpp
index 5e1b5e5..a3514bf 100644 (file)
--- a/src/mc/mc_dwarf.cpp
+++ b/src/mc/mc_dwarf.cpp
@@ -978,9 +978,8 @@ 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;
@@ -990,6 +989,23 @@ 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, 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;
+  }
+}
+
 /** \brief Populate the debugging informations of the given ELF object
  *
  *  Read the DWARf information of the EFFL object and populate the
@@ -998,34 +1014,37 @@ 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");
+
   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 == nullptr)
+  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;
+
+  Dwarf* dwarf = dwarf_begin_elf (elf, DWARF_C_READ, nullptr);
+  // Dwarf *dwarf = dwarf_begin(fd, DWARF_C_READ);
+  if (dwarf != nullptr) {
+    read_dwarf_info(info, dwarf);
+    dwarf_end(dwarf);
+    dwarf = nullptr;
+  }
+  else
     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)
-    info->flags |= simgrid::mc::ObjectInformation::Executable;
-
-  // 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;
-  }
-
-  dwarf_end(dwarf);
+  elf_end(elf);
   close(fd);
 }