From bab443ab4f756ef80f814af0353143f41e90e6a6 Mon Sep 17 00:00:00 2001

From: Jan Kratochvil <jan.kratochvil@redhat.com>

Date: Mon, 17 Aug 2020 21:58:19 +0200

Subject: [PATCH 4/6] [NFC] debugedit: Move code to separate functions.

New functions edit_strp, skip_form and edit_attributes_str_comp_dir

called by edit_attributes.

Split part of read_dwarf2_line into a read_dwarf4_line function.

New function edit_dwarf2_any_str called by edit_dwarf2 at the end of

phase 0 to rebuild .debug_str.

---

 tools/debugedit.c | 367 ++++++++++++++++++++++++++--------------------

 1 file changed, 212 insertions(+), 155 deletions(-)

diff --git a/tools/debugedit.c b/tools/debugedit.c

index 87c1cd622..7464883c5 100644

--- a/tools/debugedit.c

+++ b/tools/debugedit.c

@@ -1457,37 +1457,128 @@ edit_dwarf2_line (DSO *dso)

     }

 }

-/* Called during phase zero for each debug_line table referenced from

-   .debug_info.  Outputs all source files seen and records any

-   adjustments needed in the debug_list data structures. Returns true

-   if line_table needs to be rewrite either the dir or file paths. */

+/* Record or adjust (according to phase) DW_FORM_strp.  */

+static void

+edit_strp (DSO *dso, unsigned char *ptr, int phase, bool handled_strp)

+{

+  unsigned char *ptr_orig = ptr;

+

+  /* In the first pass we collect all strings, in the

+     second we put the new references back (if there are

+     any changes).  */

+  if (phase == 0)

+    {

+      /* handled_strp is set for attributes referring to

+	 files. If it is set the string is already

+	 recorded. */

+      if (! handled_strp)

+	{

+	  size_t idx = do_read_32_relocated (ptr);

+	  record_existing_string_entry_idx (&dso->strings, idx);

+	}

+    }

+  else if (need_strp_update) /* && phase == 1 */

+    {

+      struct stridxentry *entry;

+      size_t idx, new_idx;

+      idx = do_read_32_relocated (ptr);

+      entry = string_find_entry (&dso->strings, idx);

+      new_idx = strent_offset (entry->entry);

+      do_write_32_relocated (ptr, new_idx);

+    }

+

+  assert (ptr == ptr_orig);

+}

+

+/* Adjust *PTRP after the current *FORMP, update *FORMP for FORM_INDIRECT.  */

+static enum { FORM_OK, FORM_ERROR, FORM_INDIRECT }

+skip_form (DSO *dso, uint32_t *formp, unsigned char **ptrp)

+{

+  size_t len = 0;

+

+  switch (*formp)

+    {

+    case DW_FORM_ref_addr:

+      if (cu_version == 2)

+	*ptrp += ptr_size;

+      else

+	*ptrp += 4;

+      break;

+    case DW_FORM_flag_present:

+      break;

+    case DW_FORM_addr:

+      *ptrp += ptr_size;

+      break;

+    case DW_FORM_ref1:

+    case DW_FORM_flag:

+    case DW_FORM_data1:

+      ++*ptrp;

+      break;

+    case DW_FORM_ref2:

+    case DW_FORM_data2:

+      *ptrp += 2;

+      break;

+    case DW_FORM_ref4:

+    case DW_FORM_data4:

+    case DW_FORM_sec_offset:

+      *ptrp += 4;

+      break;

+    case DW_FORM_ref8:

+    case DW_FORM_data8:

+    case DW_FORM_ref_sig8:

+      *ptrp += 8;

+      break;

+    case DW_FORM_sdata:

+    case DW_FORM_ref_udata:

+    case DW_FORM_udata:

+      read_uleb128 (*ptrp);

+      break;

+    case DW_FORM_strp:

+      *ptrp += 4;

+      break;

+    case DW_FORM_string:

+      *ptrp = (unsigned char *) strchr ((char *)*ptrp, '\0') + 1;

+      break;

+    case DW_FORM_indirect:

+      *formp = read_uleb128 (*ptrp);

+      return FORM_INDIRECT;

+    case DW_FORM_block1:

+      len = *(*ptrp)++;

+      break;

+    case DW_FORM_block2:

+      len = read_16 (*ptrp);

+      *formp = DW_FORM_block1;

+      break;

+    case DW_FORM_block4:

+      len = read_32 (*ptrp);

+      *formp = DW_FORM_block1;

+      break;

+    case DW_FORM_block:

+    case DW_FORM_exprloc:

+      len = read_uleb128 (*ptrp);

+      *formp = DW_FORM_block1;

+      assert (len < UINT_MAX);

+      break;

+    default:

+      error (0, 0, "%s: Unknown DWARF DW_FORM_%d", dso->filename, *formp);

+      return FORM_ERROR;

+    }

+

+  if (*formp == DW_FORM_block1)

+    *ptrp += len;

+

+  return FORM_OK;

+}

+

+/* Part of read_dwarf2_line processing DWARF-4.  */

 static bool

-read_dwarf2_line (DSO *dso, uint32_t off, char *comp_dir)

+read_dwarf4_line (DSO *dso, unsigned char *ptr, char *comp_dir,

+		  struct line_table *table)

 {

-  unsigned char *ptr, *dir;

   unsigned char **dirt;

   uint32_t value, dirt_cnt;

   size_t comp_dir_len = !comp_dir ? 0 : strlen (comp_dir);

-  struct line_table *table;

-

-  if (get_line_table (dso, off, &table) == false

-      || table == NULL)

-    return false;

-

-  /* Skip to the directory table. The rest of the header has already

-     been read and checked by get_line_table. */

-  ptr = debug_sections[DEBUG_LINE].data + off;

-  ptr += (4 /* unit len */

-	  + 2 /* version */

-	  + 4 /* header len */

-	  + 1 /* min instr len */

-	  + (table->version >= 4) /* max op per instr, if version >= 4 */

-	  + 1 /* default is stmt */

-	  + 1 /* line base */

-	  + 1 /* line range */

-	  + 1 /* opcode base */

-	  + table->opcode_base - 1); /* opcode len table */

-  dir = ptr;

+  unsigned char *dir = ptr;

   /* dir table: */

   value = 1;

@@ -1620,6 +1711,40 @@ read_dwarf2_line (DSO *dso, uint32_t off, char *comp_dir)

       read_uleb128 (ptr);

     }

+  return true;

+}

+

+/* Called during phase zero for each debug_line table referenced from

+   .debug_info.  Outputs all source files seen and records any

+   adjustments needed in the debug_list data structures. Returns true

+   if line_table needs to be rewrite either the dir or file paths. */

+static bool

+read_dwarf2_line (DSO *dso, uint32_t off, char *comp_dir)

+{

+  unsigned char *ptr;

+  struct line_table *table;

+

+  if (get_line_table (dso, off, &table) == false

+      || table == NULL)

+    return false;

+

+  /* Skip to the directory table. The rest of the header has already

+     been read and checked by get_line_table. */

+  ptr = debug_sections[DEBUG_LINE].data + off;

+  ptr += (4 /* unit len */

+	  + 2 /* version */

+	  + 4 /* header len */

+	  + 1 /* min instr len */

+	  + (table->version >= 4) /* max op per instr, if version >= 4 */

+	  + 1 /* default is stmt */

+	  + 1 /* line base */

+	  + 1 /* line range */

+	  + 1 /* opcode base */

+	  + table->opcode_base - 1); /* opcode len table */

+

+  if (! read_dwarf4_line (dso, ptr, comp_dir, table))

+   return false;

+

   dso->lines.debug_lines_len += 4 + table->unit_length + table->size_diff;

   return table->replace_dirs || table->replace_files;

 }

@@ -1637,6 +1762,33 @@ find_new_list_offs (struct debug_lines *lines, size_t idx)

   return table->new_idx;

 }

+/* Read DW_FORM_strp collecting compilation directory.  */

+static void

+edit_attributes_str_comp_dir (DSO *dso, unsigned char **ptrp, int phase,

+			      char **comp_dirp, bool *handled_strpp)

+{

+  const char *dir;

+  size_t idx = do_read_32_relocated (*ptrp);

+  /* In phase zero we collect the comp_dir.  */

+  if (phase == 0)

+    {

+      if (idx >= debug_sections[DEBUG_STR].size)

+	error (1, 0, "%s: Bad string pointer index %zd for comp_dir",

+	       dso->filename, idx);

+      dir = (char *) debug_sections[DEBUG_STR].data + idx;

+

+      free (*comp_dirp);

+      *comp_dirp = strdup (dir);

+    }

+

+  if (dest_dir != NULL && phase == 0)

+    {

+      if (record_file_string_entry_idx (&dso->strings, idx))

+	need_strp_update = true;

+      *handled_strpp = true;

+    }

+}

+

 /* This scans the attributes of one DIE described by the given abbrev_tag.

    PTR points to the data in the debug_info. It will be advanced till all

    abbrev data is consumed. In phase zero data is collected, in phase one

@@ -1655,7 +1807,6 @@ edit_attributes (DSO *dso, unsigned char *ptr, struct abbrev_tag *t, int phase)

   for (i = 0; i < t->nattr; ++i)

     {

       uint32_t form = t->attr[i].form;

-      size_t len = 0;

       while (1)

 	{

 	  /* Whether we already handled a string as file for this

@@ -1743,29 +1894,8 @@ edit_attributes (DSO *dso, unsigned char *ptr, struct abbrev_tag *t, int phase)

 		}

 	      else if (form == DW_FORM_strp &&

 		       debug_sections[DEBUG_STR].data)

-		{

-		  const char *dir;

-		  size_t idx = do_read_32_relocated (ptr);

-		  /* In phase zero we collect the comp_dir.  */

-		  if (phase == 0)

-		    {

-		      if (idx >= debug_sections[DEBUG_STR].size)

-			error (1, 0,

-			       "%s: Bad string pointer index %zd for comp_dir",

-			       dso->filename, idx);

-		      dir = (char *) debug_sections[DEBUG_STR].data + idx;

-

-		      free (comp_dir);

-		      comp_dir = strdup (dir);

-		    }

-

-		  if (dest_dir != NULL && phase == 0)

-		    {

-		      if (record_file_string_entry_idx (&dso->strings, idx))

-			need_strp_update = true;

-		      handled_strp = true;

-		    }

-		}

+		edit_attributes_str_comp_dir (dso, &ptr, phase, &comp_dir,

+					      &handled_strp);

 	    }

 	  else if ((t->tag == DW_TAG_compile_unit

 		    || t->tag == DW_TAG_partial_unit)

@@ -1815,99 +1945,21 @@ edit_attributes (DSO *dso, unsigned char *ptr, struct abbrev_tag *t, int phase)

 	  switch (form)

 	    {

-	    case DW_FORM_ref_addr:

-	      if (cu_version == 2)

-		ptr += ptr_size;

-	      else

-		ptr += 4;

-	      break;

-	    case DW_FORM_flag_present:

-	      break;

-	    case DW_FORM_addr:

-	      ptr += ptr_size;

-	      break;

-	    case DW_FORM_ref1:

-	    case DW_FORM_flag:

-	    case DW_FORM_data1:

-	      ++ptr;

-	      break;

-	    case DW_FORM_ref2:

-	    case DW_FORM_data2:

-	      ptr += 2;

-	      break;

-	    case DW_FORM_ref4:

-	    case DW_FORM_data4:

-	    case DW_FORM_sec_offset:

-	      ptr += 4;

-	      break;

-	    case DW_FORM_ref8:

-	    case DW_FORM_data8:

-	    case DW_FORM_ref_sig8:

-	      ptr += 8;

-	      break;

-	    case DW_FORM_sdata:

-	    case DW_FORM_ref_udata:

-	    case DW_FORM_udata:

-	      read_uleb128 (ptr);

-	      break;

 	    case DW_FORM_strp:

-	      /* In the first pass we collect all strings, in the

-		 second we put the new references back (if there are

-		 any changes).  */

-	      if (phase == 0)

-		{

-		  /* handled_strp is set for attributes referring to

-		     files. If it is set the string is already

-		     recorded. */

-		  if (! handled_strp)

-		    {

-		      size_t idx = do_read_32_relocated (ptr);

-		      record_existing_string_entry_idx (&dso->strings, idx);

-		    }

-		}

-	      else if (need_strp_update) /* && phase == 1 */

-		{

-		  struct stridxentry *entry;

-		  size_t idx, new_idx;

-		  idx = do_read_32_relocated (ptr);

-		  entry = string_find_entry (&dso->strings, idx);

-		  new_idx = strent_offset (entry->entry);

-		  do_write_32_relocated (ptr, new_idx);

-		}

-	      ptr += 4;

-	      break;

-	    case DW_FORM_string:

-	      ptr = (unsigned char *) strchr ((char *)ptr, '\0') + 1;

-	      break;

-	    case DW_FORM_indirect:

-	      form = read_uleb128 (ptr);

-	      continue;

-	    case DW_FORM_block1:

-	      len = *ptr++;

-	      break;

-	    case DW_FORM_block2:

-	      len = read_16 (ptr);

-	      form = DW_FORM_block1;

+	      edit_strp (dso, ptr, phase, handled_strp);

 	      break;

-	    case DW_FORM_block4:

-	      len = read_32 (ptr);

-	      form = DW_FORM_block1;

-	      break;

-	    case DW_FORM_block:

-	    case DW_FORM_exprloc:

-	      len = read_uleb128 (ptr);

-	      form = DW_FORM_block1;

-	      assert (len < UINT_MAX);

+	    }

+

+	  switch (skip_form (dso, &form, &ptr))

+	    {

+	    case FORM_OK:

 	      break;

-	    default:

-	      error (0, 0, "%s: Unknown DWARF DW_FORM_%d", dso->filename,

-		     form);

+	    case FORM_ERROR:

 	      return NULL;

+	    case FORM_INDIRECT:

+	      continue;

 	    }

-	  if (form == DW_FORM_block1)

-	    ptr += len;

-

 	  break;

 	}

     }

@@ -2068,6 +2120,28 @@ edit_info (DSO *dso, int phase, struct debug_section *sec)

   return 0;

 }

+/* Rebuild .debug_str.  */

+static void

+edit_dwarf2_any_str (DSO *dso)

+{

+  Strtab *strtab = dso->strings.str_tab;

+  Elf_Data *strdata = debug_sections[DEBUG_STR].elf_data;

+  int strndx = debug_sections[DEBUG_STR].sec;

+  Elf_Scn *strscn = dso->scn[strndx];

+

+  /* Out with the old. */

+  strdata->d_size = 0;

+  /* In with the new. */

+  strdata = elf_newdata (strscn);

+

+  /* We really should check whether we had enough memory,

+     but the old ebl version will just abort on out of

+     memory... */

+  strtab_finalize (strtab, strdata);

+  debug_sections[DEBUG_STR].size = strdata->d_size;

+  dso->strings.str_buf = strdata->d_buf;

+}

+

 static int

 edit_dwarf2 (DSO *dso)

 {

@@ -2466,24 +2540,7 @@ edit_dwarf2 (DSO *dso)

 	 in place for phase 1 updating of debug_info

 	 references. */

       if (phase == 0 && need_strp_update)

-	{

-	  Strtab *strtab = dso->strings.str_tab;

-	  Elf_Data *strdata = debug_sections[DEBUG_STR].elf_data;

-	  int strndx = debug_sections[DEBUG_STR].sec;

-	  Elf_Scn *strscn = dso->scn[strndx];

-

-	  /* Out with the old. */

-	  strdata->d_size = 0;

-	  /* In with the new. */

-	  strdata = elf_newdata (strscn);

-

-	  /* We really should check whether we had enough memory,

-	     but the old ebl version will just abort on out of

-	     memory... */

-	  strtab_finalize (strtab, strdata);

-	  debug_sections[DEBUG_STR].size = strdata->d_size;

-	  dso->strings.str_buf = strdata->d_buf;

-	}

+	edit_dwarf2_any_str (dso);

     }

-- 

2.18.4