Add support for 64-bit DWARF 2 formats to gas.

gas/ChangeLog

@@ -1,3 +1,13 @@
+2002-11-18  Kevin Buettner  <kevinb@redhat.com>
+
+	* dwarf2dbg.h (dwarf2_format): New enum.
+	* dwarf2dbg.c (DWARF2_FORMAT): Provide default definition.
+	(out_debug_line, out_debug_info): Add code for handling 64-bit
+	DWARF 2 formats.
+	* config/tc-mips.h (mips_dwarf2_format): Declare.
+	* config/tc-mips.c (mips_dwarf2_format): New function.
+	* doc/internals.texi (DWARF2_FORMAT): Document.
+
 2002-11-18  Alexandre Oliva  <aoliva@redhat.com>
 
 	* config/tc-mips.c (s_change_section): Make sure input buffer

gas/config/tc-mips.c

@@ -14550,3 +14550,12 @@ MIPS options:\n\
 -64			create 64 ABI object file\n"));
 #endif
 }
+
+enum dwarf2_format
+mips_dwarf2_format ()
+{
+  if (mips_abi == N64_ABI)
+    return dwarf2_format_64bit_irix;
+  else
+    return dwarf2_format_32bit;
+}

gas/config/tc-mips.h

@@ -182,4 +182,7 @@ extern void mips_flush_pending_output PARAMS ((void));
 extern void mips_enable_auto_align PARAMS ((void));
 #define md_elf_section_change_hook()	mips_enable_auto_align()
 
+extern enum dwarf2_format mips_dwarf2_format PARAMS ((void));
+#define DWARF2_FORMAT() mips_dwarf2_format ()
+
 #endif /* TC_MIPS */

gas/doc/internals.texi

@@ -1482,6 +1482,27 @@ The COFF @code{.section} directive will use the value of this macro to set
 a new section's attributes when a directive has no valid flags or when the
 flag is @code{w}. The default value of the macro is @code{SEC_LOAD | SEC_DATA}.
 
+@item DWARF2_FORMAT ()
+@cindex DWARF2_FORMAT
+If you define this, it should return one of @code{dwarf2_format_32bit},
+@code{dwarf2_format_64bit}, or @code{dwarf2_format_64bit_irix} to indicate
+the size of internal DWARF section offsets and the format of the DWARF initial
+length fields.  When @code{dwarf2_format_32bit} is returned, the initial
+length field will be 4 bytes long and section offsets are 32 bits in size.
+For @code{dwarf2_format_64bit} and @code{dwarf2_format_64bit_irix}, section
+offsets are 64 bits in size, but the initial length field differs.  An 8 byte
+initial length is indicated by @code{dwarf2_format_64bit_irix} and
+@code{dwarf2_format_64bit} indicates a 12 byte initial length field in
+which the first four bytes are 0xffffffff and the next 8 bytes are
+the section's length.
+
+If you don't define this, @code{dwarf2_format_32bit} will be used as
+the default.
+
+This define only affects @code{.debug_info} and @code{.debug_line}
+sections generated by the assembler.  DWARF 2 sections generated by
+other tools will be unaffected by this setting.
+
 @end table
 
 @node Object format backend

gas/dwarf2dbg.c

@@ -43,6 +43,10 @@
 
 #include "dwarf2dbg.h"
 
+#ifndef DWARF2_FORMAT
+#define DWARF2_FORMAT() dwarf2_format_32bit
+#endif
+
 #ifdef BFD_ASSEMBLER
 
 #include "subsegs.h"
@@ -999,6 +1003,8 @@ out_debug_line (line_seg)
   symbolS *prologue_end;
   symbolS *line_end;
   struct line_seg *s;
+  enum dwarf2_format d2f;
+  int sizeof_offset;
 
   subseg_set (line_seg, 0);
 
@@ -1010,8 +1016,31 @@ out_debug_line (line_seg)
   expr.X_op = O_subtract;
   expr.X_add_symbol = line_end;
   expr.X_op_symbol = line_start;
-  expr.X_add_number = -4;
-  emit_expr (&expr, 4);
+
+  d2f = DWARF2_FORMAT ();
+  if (d2f == dwarf2_format_32bit)
+    {
+      expr.X_add_number = -4;
+      emit_expr (&expr, 4);
+      sizeof_offset = 4;
+    }
+  else if (d2f == dwarf2_format_64bit)
+    {
+      expr.X_add_number = -12;
+      out_four (-1);
+      emit_expr (&expr, 8);
+      sizeof_offset = 8;
+    }
+  else if (d2f == dwarf2_format_64bit_irix)
+    {
+      expr.X_add_number = -8;
+      emit_expr (&expr, 8);
+      sizeof_offset = 8;
+    }
+  else
+    {
+      as_fatal (_("internal error: unknown dwarf2 format"));
+    }
 
   /* Version.  */
   out_two (2);
@@ -1021,7 +1050,7 @@ out_debug_line (line_seg)
   expr.X_add_symbol = prologue_end;
   expr.X_op_symbol = line_start;
   expr.X_add_number = - (4 + 2 + 4);
-  emit_expr (&expr, 4);
+  emit_expr (&expr, sizeof_offset);
 
   /* Parameters of the state machine.  */
   out_byte (DWARF2_LINE_MIN_INSN_LENGTH);
@@ -1174,6 +1203,8 @@ out_debug_info (info_seg, abbrev_seg, line_seg)
   symbolS *info_end;
   char *p;
   int len;
+  enum dwarf2_format d2f;
+  int sizeof_offset;
 
   subseg_set (info_seg, 0);
 
@@ -1184,8 +1215,31 @@ out_debug_info (info_seg, abbrev_seg, line_seg)
   expr.X_op = O_subtract;
   expr.X_add_symbol = info_end;
   expr.X_op_symbol = info_start;
-  expr.X_add_number = -4;
-  emit_expr (&expr, 4);
+
+  d2f = DWARF2_FORMAT ();
+  if (d2f == dwarf2_format_32bit)
+    {
+      expr.X_add_number = -4;
+      emit_expr (&expr, 4);
+      sizeof_offset = 4;
+    }
+  else if (d2f == dwarf2_format_64bit)
+    {
+      expr.X_add_number = -12;
+      out_four (-1);
+      emit_expr (&expr, 8);
+      sizeof_offset = 8;
+    }
+  else if (d2f == dwarf2_format_64bit_irix)
+    {
+      expr.X_add_number = -8;
+      emit_expr (&expr, 8);
+      sizeof_offset = 8;
+    }
+  else
+    {
+      as_fatal (_("internal error: unknown dwarf2 format"));
+    }
 
   /* DWARF version.  */
   out_two (2);
@@ -1194,7 +1248,7 @@ out_debug_info (info_seg, abbrev_seg, line_seg)
   expr.X_op = O_symbol;
   expr.X_add_symbol = section_symbol (abbrev_seg);
   expr.X_add_number = 0;
-  emit_expr (&expr, 4);
+  emit_expr (&expr, sizeof_offset);
 
   /* Target address size.  */
   out_byte (sizeof_address);

gas/dwarf2dbg.h

@@ -69,4 +69,17 @@ extern int dwarf2dbg_estimate_size_before_relax PARAMS ((fragS *));
 extern int dwarf2dbg_relax_frag PARAMS ((fragS *));
 extern void dwarf2dbg_convert_frag PARAMS ((fragS *));
 
+/* An enumeration which describes the sizes of offsets (to DWARF sections)
+   and the mechanism by which the size is indicated.  */
+enum dwarf2_format {
+  /* 32-bit format: the initial length field is 4 bytes long.  */
+  dwarf2_format_32bit,
+  /* DWARF3 64-bit format: the representation of the initial length
+     (of a DWARF section) is 0xffffffff (4 bytes) followed by eight
+     bytes indicating the actual length.  */
+  dwarf2_format_64bit,
+  /* SGI extension to DWARF2: The initial length is eight bytes.  */
+  dwarf2_format_64bit_irix
+};
+
 #endif /* AS_DWARF2DBG_H */