On Sat, Feb 28, 2015 at 10:14 AM, Max Filippov <jcmvb...@gmail.com> wrote:
> call0 is an ABI that doesn't use register windows.
>
> 2015-02-28 Max Filippov <jcmvb...@gmail.com>
>
> gcc/
> * config/xtensa/constraints.md ("a" constraint): Include stack
> pointer in case of call0 ABI.
> ("q" constraint): Make empty in case of call0 ABI.
> ("D" constraint): Include stack pointer in case of call0 ABI.
>
> * config/xtensa/xtensa-protos.h (xtensa_set_return_address,
> xtensa_expand_epilogue, xtensa_regno_to_class): Add new function
> prototypes.
>
> * config/xtensa/xtensa.c (xtensa_callee_save_size): New
> variable.
> (xtensa_regno_to_class): Make it a local variable in the
> function xtensa_regno_to_class.
> (xtensa_function_epilogue, TARGET_ASM_FUNCTION_EPILOGUE): Remove
> macro, function prototype and implementation.
> (reg_nonleaf_alloc_order): Make it a local variable in the
> function order_regs_for_local_alloc.
> (xtensa_conditional_register_usage): New function.
> (TARGET_CONDITIONAL_REGISTER_USAGE): Define macro.
> (xtensa_valid_move): Allow direct moves to stack pointer
> register in call0 ABI.
> (xtensa_setup_frame_addresses): Only spill register windows in
> windowed ABI.
> (xtensa_emit_call): Emit call(x)8 or call(x)0 in windowed and
> call0 ABI respectively.
> (xtensa_function_arg_1): Only mark a7 register for copying in
> windowed ABI.
> (xtensa_call_save_reg): New function.
> (compute_frame_size): Add space for callee saved register
> storage to the frame size in call0 ABI.
> (xtensa_expand_prologue): Generate code to set up stack frame
> and save callee-saved registers in call0 ABI.
> (xtensa_expand_epilogue): New function.
> (xtensa_set_return_address): New function.
> (xtensa_return_addr): Calculate return address in call0 ABI.
> (xtensa_builtin_saveregs): Only mark a7 register for copying and
> emit copying code in windowed ABI.
> (order_regs_for_local_alloc): Add preferred register allocation
> order for non-leaf function in call0 ABI.
> (xtensa_static_chain): Add atatic chain passing for call0 ABI.
> (xtensa_asm_trampoline_template): Add trampoline generation for
> call0 ABI.
> (xtensa_trampoline_init): Add trampoline initialization for
> call0 ABI.
> (xtensa_conditional_register_usage, xtensa_regno_to_class): New
> functions.
>
> * config/xtensa/xtensa.h (TARGET_WINDOWED_ABI): New macro.
> (TARGET_CPU_CPP_BUILTINS): Add built-in define for call0 ABI.
> (CALL_USED_REGISTERS): Modify to encode both windowed and call0
> ABI call-used registers.
> (HARD_FRAME_POINTER_REGNUM): Add frame pointer for call0 ABI.
> (INCOMING_REGNO, OUTGOING_REGNO): Use argument unchanged in
> call0 ABI.
> (REG_CLASS_CONTENTS): Include all registers into the preferred
> reload registers set, adjust the set in the
> xtensa_conditional_register_usage.
> (xtensa_regno_to_class): Drop variable declaration.
> (REGNO_REG_CLASS): Redefine to use xtensa_regno_to_class
> function.
> (WINDOW_SIZE): Define as 8 or 0 for windowed and call0 ABI
> respectively.
> (FUNCTION_PROFILER): Add _mcount call for call0 ABI.
> (TRAMPOLINE_SIZE): Define trampoline size for call0 ABI.
> (RETURN_ADDR_IN_PREVIOUS_FRAME): Define to 0 in call0 ABI.
> (ASM_OUTPUT_POOL_PROLOGUE): Always generate literal pool
> location in call0 ABI.
> (EH_RETURN_STACKADJ_RTX): New definition, use a10 for passing
> stack adjustment size when handling exception.
> (CRT_CALL_STATIC_FUNCTION): Add definition for call0 ABI.
>
> * config/xtensa/xtensa.md (A9_REG, UNSPECV_BLOCKAGE): New
> definitions.
> ("return" pattern): Generate ret.n/ret in call0 ABI.
> ("epilogue" pattern): Expand epilogue.
> ("nonlocal_goto" pattern): Use default in call0 ABI.
> ("eh_return" pattern): Move implementation to eh_set_a0_windowed,
> emit eh_set_a0_* depending on ABI.
> ("eh_set_a0_windowed" pattern): Former eh_return pattern.
> ("eh_set_a0_call0", "blockage"): New patterns.
>
> libgcc/
> * config/xtensa/lib2funcs.S (__xtensa_libgcc_window_spill,
> __xtensa_nonlocal_goto): Don't compile for call0 ABI.
> (__xtensa_sync_caches): Only use entry and retw in windowed ABI,
> use ret in call0 ABI.
>
> * config/xtensa/t-windowed: New file.
>
> * libgcc/config/xtensa/t-xtensa (LIB2ADDEH): Move to t-windowed.
>
> * libgcc/configure: Regenerated.
>
> * libgcc/configure.ac: Check if xtensa target is configured for
> windowed ABI and thus needs to use custom unwind code.
This is OK for xtensa.
