> Yes, I have changed a few things, patch attached.  The basic stuff works,
> but not yet the fancy features (non-local gotos, setjmp/longjmp and
> exceptions). I'm also working on the GDB side.

I've now installed the attached version.  It adds support for the above fancy 
features plus sibling calls, frame pointer elimination and 64-bit code in flat 
mode.  I'll submit the associated GDB patch sometime next week.

It also contains a few changes for the regular mode:
 - %fp isn't a fixed register anymore,
 - EXIT_IGNORE_STACK is defined to 1 unconditionally,
 - __builtin_eh_return is more correctly implemented,
 - sparc_legitimate_address_p was wrongly rejecting offsettable addresses when 
the offset was too close to 4095.

Bootstrapped/regtested on SPARC/Solaris and SPARC64/Solaris.  The C testsuite 
is 100% clean in flat mode; for the others, you need at least -mflat multlibs.


2011-06-10  Eric Botcazou  <ebotcazou@adacore.com>
	    Laurent Rougé  <laurent.rouge@menta.fr>

	* doc/invoke.texi (SPARC options): Add -mflat.
	* config/sparc/sparc.opt: Likewise.
	* config/sparc/sparc-protos.h (sparc_expand_epilogue): Add parameter.
	(sparc_flat_expand_prologue): Declare.
	(sparc_flat_expand_epilogue): Likewise.
	* config/sparc/sparc.h (CPP_CPU_SPEC): Do not handle -msoft-float.
	(CPP_ENDIAN_SPEC): Replace with...
	(CPP_OTHER_SPEC): ...this.  Also handle -mflat and -msoft-float.
	(CPP_SPEC): Adjust to above change.
	(EXTRA_SPECS): Likewise.
	(SPARC_INCOMING_INT_ARG_FIRST): Add TARGET_FLAT handling.
	(INCOMING_REGNO): Likewise.
	(OUTGOING_REGNO): Likewise.
	(LOCAL_REGNO): Likewise.
	(SETUP_FRAME_ADDRESSES): Likewise.
	(FIXED_REGISTERS): Set 0 for %fp.
	(CALL_USED_REGISTERS): Likewise.
	(INITIAL_ELIMINATION_OFFSET): Pass current_function_is_leaf.
	(EXIT_IGNORE_STACK): Define to 1 unconditionally.
	(RETURN_ADDR_REGNUM): Define.
	(RETURN_ADDR_RTX): Use it.
	(INCOMING_RETURN_ADDR_REGNUM): Define.
	(INCOMING_RETURN_ADDR_RTX): Use it.
	(DWARF_FRAME_RETURN_COLUMN): Likewise.
	(EH_RETURN_REGNUM): Define.
	(EH_RETURN_STACKADJ_RTX): Use it.
	(EH_RETURN_HANDLER_RTX): Delete.
	(EPILOGUE_USES): Use them and add TARGET_FLAT handling.
	* config/sparc/sparc.c (apparent_fsize, actual_fsize, num_gfregs):
	Delete.
	(struct machine_function): Add frame_size, apparent_frame_size,
	frame_base_reg, frame_base_offset, n_global_fp_regs and
	save_local_in_regs_p fields.
	(sparc_frame_size, sparc_apparent_frame_size, sparc_frame_base_reg,
	sparc_frame_base_offset, sparc_n_global_fp_regs,
	sparc_save_local_in_regs_p): New macros.
	(sparc_option_override): Error out if -fcall-saved-REG is specified
	for Out registers.
	(eligible_for_restore_insn): Fix formatting.
	(eligible_for_return_delay): Likewise.  Add TARGET_FLAT handling.
	(eligible_for_sibcall_delay): Likewise.
	(RTX_OK_FOR_OFFSET_P, RTX_OK_FOR_OLO10_P): Add MODE parameter.
	(sparc_legitimate_address_p): Adjust to above change.
	(save_global_or_fp_reg_p): New predicate.
	(return_addr_reg_needed_p): Likewise.
	(save_local_or_in_reg_p): Likewise.
	(sparc_compute_frame_size): Use them.  Add TARGET_FLAT handling.
	(SORR_SAVE, SORR_RESTORE): Delete.
	(sorr_pred_t): New typedef.
	(sorr_act_t): New enum.
	(save_or_restore_regs): Rename to...
	(emit_save_or_restore_regs): ...this.  Change type of LOW and HIGH
	parameters, remove ACTION parameter, add LEAF_FUNCTION_P, SAVE_P,
	ACTION_TRUE and ACTION_FALSE parameters.  Implement more general
	mechanism.  Add CFI information for double-word saves in 32-bit mode.
	(emit_adjust_base_to_offset): New function extracted from...
	(emit_save_or_restore_regs): ...this.  Rename the rest to...
	(emit_save_or_restore_regs_global_fp_regs): ...this.
	(emit_save_or_restore_regs_local_in_regs): New function.
	(gen_create_flat_frame_[123]): New functions.
	(sparc_expand_prologue): Use SIZE local variable.  Adjust.
	(sparc_flat_expand_prologue): New function.
	(sparc_asm_function_prologue): Add TARGET_FLAT handling.
	(sparc_expand_epilogue): Use SIZE local variable.  Adjust.
	(sparc_flat_expand_epilogue): New function.
	(sparc_can_use_return_insn_p): Add TARGET_FLAT handling.
	(output_return): Likewise.
	(output_sibcall): Likewise.
	(sparc_output_mi_thunk): Likewise.
	(sparc_frame_pointer_required): Likewise.
	(sparc_conditional_register_usage): If TARGET_FLAT, disable the leaf
	function optimization.
	* config/sparc/sparc.md (flat): New attribute.
	(prologue): Add TARGET_FLAT handling.
	(save_register_window): Disable if TARGET_FLAT.
	(create_flat_frame_[123]): New patterns.
	(epilogue): Add TARGET_FLAT handling.
	(sibcall_epilogue): Likewise.
	(eh_return): New expander.
	(eh_return_internal): New insn and splitter.
	(return_internal): Add TARGET_FLAT handling.
	(untyped_return): Remove bogus test and use RETURN_ADDR_REGNUM.
	(save_stack_nonlocal): Use RETURN_ADDR_REGNUM.
	(nonlocal_goto): Add TARGET_FLAT handling.
	* config/sparc/t-elf: Add -mflat multilib.
	* config/sparc/t-leon: Likewise.


2011-06-10  Eric Botcazou  <ebotcazou@adacore.com>
            Laurent Rougé  <laurent.rouge@menta.fr>

	* gcc.dg/20020503-1.c: Add back -mflat option on the SPARC.
	* gcc.target/sparc/sparc-ret.c: Skip if -mflat is passed.


2011-06-10  Eric Botcazou  <ebotcazou@adacore.com>

	* config/sparc/linux-unwind.h (STACK_BIAS): Define.
	(sparc64_fallback_frame_state): Use it.
	(sparc64_frob_update_context): Further adjust context.
	* config/sparc/sol2-unwind.h (sparc64_frob_update_context): Likewise.
	* config/sparc/sol2-ci.S: Add TARGET_FLAT handling.
	* config/sparc/sol2-cn.S: Likewise.


-- 
Eric Botcazou