got-relative eh info for x86

[Richard Henderson]

See if this works for you.  I was able to get a good test run
on Linux using headers suitably hacked to use the GOT-relative
relocs.  (A reason to make GOT-relative not the default on
Linux is that you need GAS 2.11 for @GOTOFF to be accepted in
anything but an instruction memory operand context.)

I do think that all ELF systems should have their crtbegin 
file go ahead and use __register_frame_info_bases and provide
the GOT so that future gcc versions can use GOT-relative relocs
if we want.


r~


	* config/i386/linux.h (ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX): New.
	(CRT_GET_RFIB_DATA): New.
	* config/i386/sysv4.h: Likewise.
	* config/i386/sco5.h: Likewise.
	(ASM_PREFERRED_EH_DATA_FORMAT): New.

Index: linux.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/i386/linux.h,v
retrieving revision 1.28
diff -u -p -r1.28 linux.h
--- linux.h	2001/05/19 17:56:48	1.28
+++ linux.h	2001/05/21 07:19:05
@@ -194,6 +194,39 @@ Boston, MA 02111-1307, USA.  */
   while (0)
 #endif
 
+/* Handle special EH pointer encodings.  Absolute, pc-relative, and
+   indirect are handled automatically.  */
+#define ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(FILE, ENCODING, SIZE, ADDR, DONE) \
+  do {									\
+    if ((SIZE) == 4 && ((ENCODING) & 0x70) == DW_EH_PE_datarel)		\
+      {									\
+        fputs (UNALIGNED_INT_ASM_OP, FILE);				\
+        assemble_name (FILE, XSTR (ADDR, 0));				\
+	fputs (((ENCODING) & DW_EH_PE_indirect ? "@GOT" : "@GOTOFF"), FILE); \
+        goto DONE;							\
+      }									\
+  } while (0)
+
+/* Used by crtstuff.c to initialize the base of data-relative relocations.
+   These are GOT relative on x86, so return the pic register.  */
+#ifdef __PIC__
+#define CRT_GET_RFIB_DATA(BASE)			\
+  {						\
+    register void *ebx_ __asm__("ebx");		\
+    BASE = ebx_;				\
+  }
+#else
+#define CRT_GET_RFIB_DATA(BASE)						\
+  __asm__ ("call\t.LPR%=\n"						\
+	   ".LPR%=:\n\t"						\
+	   "popl\t%0\n\t"						\
+	   /* Due to a GAS bug, this cannot use EAX.  That encodes	\
+	      smaller than the traditional EBX, which results in the	\
+	      offset being off by one.  */				\
+	   "addl\t$_GLOBAL_OFFSET_TABLE_+[.-.LPR%=],%0"			\
+	   : "=d"(BASE))
+#endif
+
 /* Do code reading to identify a signal frame, and set the frame
    state data appropriately.  See unwind-dw2.c for the structs.  */
 
Index: sco5.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/i386/sco5.h,v
retrieving revision 1.46
diff -u -p -r1.46 sco5.h
--- sco5.h	2001/05/20 19:54:04	1.46
+++ sco5.h	2001/05/21 07:19:06
@@ -951,3 +951,44 @@ do {									\
 } while (0)
 # endif /* ! _SCO_ELF */
 #endif /* CRT_BEGIN !! CRT_END */
+
+/* Handle special EH pointer encodings.  Absolute, pc-relative, and
+   indirect are handled automatically.  */
+#define ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(FILE, ENCODING, SIZE, ADDR, DONE) \
+  do {									\
+    if ((SIZE) == 4 && ((ENCODING) & 0x70) == DW_EH_PE_datarel)		\
+      {									\
+        fputs (UNALIGNED_INT_ASM_OP, FILE);				\
+        assemble_name (FILE, XSTR (ADDR, 0));				\
+	fputs (((ENCODING) & DW_EH_PE_indirect ? "@GOT" : "@GOTOFF"), FILE); \
+        goto DONE;							\
+      }									\
+  } while (0)
+
+/* Used by crtstuff.c to initialize the base of data-relative relocations.
+   These are GOT relative on x86, so return the pic register.  */
+#ifdef __PIC__
+#define CRT_GET_RFIB_DATA(BASE)			\
+  {						\
+    register void *ebx_ __asm__("ebx");		\
+    BASE = ebx_;				\
+  }
+#else
+#define CRT_GET_RFIB_DATA(BASE)						\
+  __asm__ ("call\t.LPR%=\n"						\
+	   ".LPR%=:\n\t"						\
+	   "popl\t%0\n\t"						\
+	   /* Due to a GAS bug, this cannot use EAX.  That encodes	\
+	      smaller than the traditional EBX, which results in the	\
+	      offset being off by one.  */				\
+	   "addl\t$_GLOBAL_OFFSET_TABLE_+[.-.LPR%=],%0"			\
+	   : "=d"(BASE))
+#endif
+
+/* Select a format to encode pointers in exception handling data.  CODE
+   is 0 for data, 1 for code labels, 2 for function pointers.  GLOBAL is
+   true if the symbol may be affected by dynamic relocations.  */
+#undef ASM_PREFERRED_EH_DATA_FORMAT
+#define ASM_PREFERRED_EH_DATA_FORMAT(CODE,GLOBAL)			\
+  (flag_pic ? (GLOBAL ? DW_EH_PE_indirect : 0) | DW_EH_PE_datarel	\
+   : DW_EH_PE_absptr)
Index: sysv4.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/i386/sysv4.h,v
retrieving revision 1.12
diff -u -p -r1.12 sysv4.h
--- sysv4.h	2001/05/20 19:54:04	1.12
+++ sysv4.h	2001/05/21 07:19:06
@@ -179,3 +179,36 @@ do { long value[3];							\
 
 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
   asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN)
+
+/* Handle special EH pointer encodings.  Absolute, pc-relative, and
+   indirect are handled automatically.  */
+#define ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(FILE, ENCODING, SIZE, ADDR, DONE) \
+  do {									\
+    if ((SIZE) == 4 && ((ENCODING) & 0x70) == DW_EH_PE_datarel)		\
+      {									\
+        fputs (UNALIGNED_INT_ASM_OP, FILE);				\
+        assemble_name (FILE, XSTR (ADDR, 0));				\
+	fputs (((ENCODING) & DW_EH_PE_indirect ? "@GOT" : "@GOTOFF"), FILE); \
+        goto DONE;							\
+      }									\
+  } while (0)
+
+/* Used by crtstuff.c to initialize the base of data-relative relocations.
+   These are GOT relative on x86, so return the pic register.  */
+#ifdef __PIC__
+#define CRT_GET_RFIB_DATA(BASE)			\
+  {						\
+    register void *ebx_ __asm__("ebx");		\
+    BASE = ebx_;				\
+  }
+#else
+#define CRT_GET_RFIB_DATA(BASE)						\
+  __asm__ ("call\t.LPR%=\n"						\
+	   ".LPR%=:\n\t"						\
+	   "popl\t%0\n\t"						\
+	   /* Due to a GAS bug, this cannot use EAX.  That encodes	\
+	      smaller than the traditional EBX, which results in the	\
+	      offset being off by one.  */				\
+	   "addl\t$_GLOBAL_OFFSET_TABLE_+[.-.LPR%=],%0"			\
+	   : "=d"(BASE))
+#endif