(output_line_info): Always use DW_LNE_set_address instead of DW_LNS_fixed_advance_pc...

(output_line_info): Always use DW_LNE_set_address instead
of DW_LNS_fixed_advance_pc for line number addresses.
(size_of_line_info): Adjust size calculation as per above change.

From-SVN: r14262

diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 4ef451f4efe55078e08bd6f8440da76dff94ec34..4af09baef00b02f36c8954dd4ada451755015e0d 100644 (file)
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -4280,6 +4280,10 @@ size_of_line_info ()
   register long line_delta;
   register unsigned long current_file;
   register unsigned long function;
+  unsigned long size_of_set_address;
+
+  /* Size of a DW_LNE_set_address instruction.  */
+  size_of_set_address = 1 + size_of_uleb128 (1 + PTR_SIZE) + 1 + PTR_SIZE;
 
   /* Version number.  */
   size = 2;
@@ -4291,7 +4295,7 @@ size_of_line_info ()
   size += size_of_line_prolog ();
 
   /* Set address register instruction.  */
-  size += 1 + size_of_uleb128 (1 + PTR_SIZE) + 1 + PTR_SIZE;
+  size += size_of_set_address;
 
   current_file = 1;
   current_line = 1;
@@ -4300,7 +4304,12 @@ size_of_line_info ()
       register dw_line_info_ref line_info;
 
       /* Advance pc instruction.  */
-      size += 1 + 2;
+      /* ??? See the DW_LNS_advance_pc comment in output_line_info.  */
+      if (0)
+       size += 1 + 2;
+      else
+       size += size_of_set_address;
+
       line_info = &line_info_table[lt_index];
       if (line_info->dw_file_num != current_file)
        {
@@ -4330,7 +4339,10 @@ size_of_line_info ()
     }
 
   /* Advance pc instruction.  */
-  size += 1 + 2;
+  if (0)
+    size += 1 + 2;
+  else
+    size += size_of_set_address;
 
   /* End of line number info. marker.  */
   size += 1 + size_of_uleb128 (1) + 1;
@@ -4346,11 +4358,16 @@ size_of_line_info ()
        {
          function = line_info->function;
          /* Set address register instruction.  */
-         size += 1 + size_of_uleb128 (1 + PTR_SIZE) + 1 + PTR_SIZE;
+         size += size_of_set_address;
        }
       else
-       /* Advance pc instruction.  */
-       size += 1 + 2;
+       {
+         /* Advance pc instruction.  */
+         if (0)
+           size += 1 + 2;
+         else
+           size += size_of_set_address;
+       }
 
       if (line_info->dw_file_num != current_file)
        {
@@ -4389,7 +4406,10 @@ size_of_line_info ()
          current_line = 1;
 
          /* Advance pc instruction.  */
-         size += 1 + 2;
+         if (0)
+           size += 1 + 2;
+         else
+           size += size_of_set_address;
 
          /* End of line number info. marker.  */
          size += 1 + size_of_uleb128 (1) + 1;
@@ -5135,7 +5155,10 @@ output_aranges ()
 }
 
 /* Output the source line number correspondence information.  This
-   information goes into the .debug_line section.  */
+   information goes into the .debug_line section.
+
+   If the format of this data changes, then the function size_of_line_info
+   must also be adjusted the same way.  */
 
 static void
 output_line_info ()
@@ -5276,15 +5299,48 @@ output_line_info ()
     {
       register dw_line_info_ref line_info;
 
-      ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNS_fixed_advance_pc);
-      if (flag_verbose_asm)
-       fprintf (asm_out_file, "\t%s DW_LNS_fixed_advance_pc",
-                ASM_COMMENT_START);
-
-      fputc ('\n', asm_out_file);
+      /* Emit debug info for the address of the current line, choosing
+        the encoding that uses the least amount of space.  */
+      /* ??? Unfortunately, we have little choice here currently, and must
+        always use the most general form.  Gcc does not know the address
+        delta itself, so we can't use DW_LNS_advance_pc.  There are no known
+        dwarf2 aware assemblers at this time, so we can't use any special
+        pseudo ops that would allow the assembler to optimally encode this for
+        us.  Many ports do have length attributes which will give an upper
+        bound on the address range.  We could perhaps use length attributes
+        to determine when it is safe to use DW_LNS_fixed_advance_pc.  */
       ASM_GENERATE_INTERNAL_LABEL (line_label, LINE_CODE_LABEL, lt_index);
-      ASM_OUTPUT_DWARF_DELTA2 (asm_out_file, line_label, prev_line_label);
-      fputc ('\n', asm_out_file);
+      if (0)
+       {
+         /* This can handle deltas up to 0xffff.  This takes 3 bytes.  */
+         ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNS_fixed_advance_pc);
+         if (flag_verbose_asm)
+           fprintf (asm_out_file, "\t%s DW_LNS_fixed_advance_pc",
+                    ASM_COMMENT_START);
+
+         fputc ('\n', asm_out_file);
+         ASM_OUTPUT_DWARF_DELTA2 (asm_out_file, line_label, prev_line_label);
+         fputc ('\n', asm_out_file);
+       }
+      else
+       {
+         /* This can handle any delta.  This takes 4+PTR_SIZE bytes.  */
+         ASM_OUTPUT_DWARF_DATA1 (asm_out_file, 0);
+         if (flag_verbose_asm)
+           fprintf (asm_out_file, "\t%s DW_LNE_set_address",
+                    ASM_COMMENT_START);
+         fputc ('\n', asm_out_file);
+         output_uleb128 (1 + PTR_SIZE);
+         fputc ('\n', asm_out_file);
+         ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNE_set_address);
+         fputc ('\n', asm_out_file);
+         ASM_OUTPUT_DWARF_ADDR (asm_out_file, line_label);
+         fputc ('\n', asm_out_file);
+       }
+      strcpy (prev_line_label, line_label);
+
+      /* Emit debug info for the source file of the current line, if
+        different from the previous line.  */
       line_info = &line_info_table[lt_index];
       if (line_info->dw_file_num != current_file)
        {
@@ -5301,11 +5357,16 @@ output_line_info ()
          fputc ('\n', asm_out_file);
        }
 
+      /* Emit debug info for the current line number, choosing the encoding
+        that uses the least amount of space.  */
       line_offset = line_info->dw_line_num - current_line;
       line_delta = line_offset - DWARF_LINE_BASE;
       current_line = line_info->dw_line_num;
       if (line_delta >= 0 && line_delta < (DWARF_LINE_RANGE - 1))
        {
+         /* This can handle deltas from -10 to 234, using the current
+            definitions of DWARF_LINE_BASE and DWARF_LINE_RANGE.  This
+            takes 1 byte.  */
          ASM_OUTPUT_DWARF_DATA1 (asm_out_file,
                                  DWARF_LINE_OPCODE_BASE + line_delta);
          if (flag_verbose_asm)
@@ -5316,6 +5377,8 @@ output_line_info ()
        }
       else
        {
+         /* This can handle any delta.  This takes at least 4 bytes, depending
+            on the value being encoded.  */
          ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNS_advance_line);
          if (flag_verbose_asm)
            fprintf (asm_out_file, "\t%s advance to line %d",
@@ -5327,17 +5390,33 @@ output_line_info ()
          ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNS_copy);
          fputc ('\n', asm_out_file);
        }
-
-      strcpy (prev_line_label, line_label);
     }
 
-  ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNS_fixed_advance_pc);
-  if (flag_verbose_asm)
-    fprintf (asm_out_file, "\t%s DW_LNS_fixed_advance_pc", ASM_COMMENT_START);
+  /* Emit debug info for the address of the end of the function.  */
+  if (0)
+    {
+      ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNS_fixed_advance_pc);
+      if (flag_verbose_asm)
+       fprintf (asm_out_file, "\t%s DW_LNS_fixed_advance_pc",
+                ASM_COMMENT_START);
 
-  fputc ('\n', asm_out_file);
-  ASM_OUTPUT_DWARF_DELTA2 (asm_out_file, text_end_label, prev_line_label);
-  fputc ('\n', asm_out_file);
+      fputc ('\n', asm_out_file);
+      ASM_OUTPUT_DWARF_DELTA2 (asm_out_file, text_end_label, prev_line_label);
+      fputc ('\n', asm_out_file);
+    }
+  else
+    {
+      ASM_OUTPUT_DWARF_DATA1 (asm_out_file, 0);
+      if (flag_verbose_asm)
+       fprintf (asm_out_file, "\t%s DW_LNE_set_address", ASM_COMMENT_START);
+      fputc ('\n', asm_out_file);
+      output_uleb128 (1 + PTR_SIZE);
+      fputc ('\n', asm_out_file);
+      ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNE_set_address);
+      fputc ('\n', asm_out_file);
+      ASM_OUTPUT_DWARF_ADDR (asm_out_file, text_end_label);
+      fputc ('\n', asm_out_file);
+    }
 
   /* Output the marker for the end of the line number info.  */
   ASM_OUTPUT_DWARF_DATA1 (asm_out_file, 0);
@@ -5358,6 +5437,9 @@ output_line_info ()
       register dw_separate_line_info_ref line_info
        = &separate_line_info_table[lt_index];
 
+      /* Emit debug info for the address of the current line.  If this is
+        a new function, or the first line of a function, then we need
+        to handle it differently.  */
       ASM_GENERATE_INTERNAL_LABEL (line_label, SEPARATE_LINE_CODE_LABEL,
                                   lt_index);
       if (function != line_info->function)
@@ -5380,16 +5462,38 @@ output_line_info ()
        }
       else
        {
-         ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNS_fixed_advance_pc);
-         if (flag_verbose_asm)
-           fprintf (asm_out_file, "\t%s DW_LNS_fixed_advance_pc",
-                    ASM_COMMENT_START);
+         /* ??? See the DW_LNS_advance_pc comment above.  */
+         if (0)
+           {
+             ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNS_fixed_advance_pc);
+             if (flag_verbose_asm)
+               fprintf (asm_out_file, "\t%s DW_LNS_fixed_advance_pc",
+                        ASM_COMMENT_START);
 
-         fputc ('\n', asm_out_file);
-         ASM_OUTPUT_DWARF_DELTA2 (asm_out_file, line_label, prev_line_label);
-         fputc ('\n', asm_out_file);
+             fputc ('\n', asm_out_file);
+             ASM_OUTPUT_DWARF_DELTA2 (asm_out_file, line_label,
+                                      prev_line_label);
+             fputc ('\n', asm_out_file);
+           }
+         else
+           {
+             ASM_OUTPUT_DWARF_DATA1 (asm_out_file, 0);
+             if (flag_verbose_asm)
+               fprintf (asm_out_file, "\t%s DW_LNE_set_address",
+                        ASM_COMMENT_START);
+             fputc ('\n', asm_out_file);
+             output_uleb128 (1 + PTR_SIZE);
+             fputc ('\n', asm_out_file);
+             ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNE_set_address);
+             fputc ('\n', asm_out_file);
+             ASM_OUTPUT_DWARF_ADDR (asm_out_file, line_label);
+             fputc ('\n', asm_out_file);
+           }
        }
+      strcpy (prev_line_label, line_label);
 
+      /* Emit debug info for the source file of the current line, if
+        different from the previous line.  */
       if (line_info->dw_file_num != current_file)
        {
          current_file = line_info->dw_file_num;
@@ -5405,6 +5509,8 @@ output_line_info ()
          fputc ('\n', asm_out_file);
        }
 
+      /* Emit debug info for the current line number, choosing the encoding
+        that uses the least amount of space.  */
       if (line_info->dw_line_num != current_line)
        {
          line_offset = line_info->dw_line_num - current_line;
@@ -5436,7 +5542,6 @@ output_line_info ()
        }
 
       ++lt_index;
-      strcpy (prev_line_label, line_label);
 
       /* If we're done with a function, end its sequence.  */
       if (lt_index == separate_line_info_table_in_use
@@ -5444,15 +5549,35 @@ output_line_info ()
        {
          current_file = 1;
          current_line = 1;
-         ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNS_fixed_advance_pc);
-         if (flag_verbose_asm)
-           fprintf (asm_out_file, "\t%s DW_LNS_fixed_advance_pc",
-                    ASM_COMMENT_START);
 
-         fputc ('\n', asm_out_file);
+         /* Emit debug info for the address of the end of the function.  */
          ASM_GENERATE_INTERNAL_LABEL (line_label, FUNC_END_LABEL, function);
-         ASM_OUTPUT_DWARF_DELTA2 (asm_out_file, line_label, prev_line_label);
-         fputc ('\n', asm_out_file);
+         if (0)
+           {
+             ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNS_fixed_advance_pc);
+             if (flag_verbose_asm)
+               fprintf (asm_out_file, "\t%s DW_LNS_fixed_advance_pc",
+                        ASM_COMMENT_START);
+
+             fputc ('\n', asm_out_file);
+             ASM_OUTPUT_DWARF_DELTA2 (asm_out_file, line_label,
+                                      prev_line_label);
+             fputc ('\n', asm_out_file);
+           }
+         else
+           {
+             ASM_OUTPUT_DWARF_DATA1 (asm_out_file, 0);
+             if (flag_verbose_asm)
+               fprintf (asm_out_file, "\t%s DW_LNE_set_address",
+                        ASM_COMMENT_START);
+             fputc ('\n', asm_out_file);
+             output_uleb128 (1 + PTR_SIZE);
+             fputc ('\n', asm_out_file);
+             ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DW_LNE_set_address);
+             fputc ('\n', asm_out_file);
+             ASM_OUTPUT_DWARF_ADDR (asm_out_file, line_label);
+             fputc ('\n', asm_out_file);
+           }
 
          /* Output the marker for the end of this sequence.  */
          ASM_OUTPUT_DWARF_DATA1 (asm_out_file, 0);