Implement call0 ABI for xtensa

call0 is an ABI that doesn't use register windows.

2015-03-03  Max Filippov  <jcmvbkbc@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.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@221158 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 15 insertions, 3 deletions

diff --git a/libgcc/config/xtensa/lib2funcs.S b/libgcc/config/xtensa/lib2funcs.S
index 1014a19732a..4d451c8c71c 100644
--- a/libgcc/config/xtensa/lib2funcs.S
+++ b/libgcc/config/xtensa/lib2funcs.S
@@ -29,6 +29,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    current register window.  This is used to set up the stack so that
    arbitrary frames can be accessed.  */
 
+#if XCHAL_HAVE_WINDOWED && !__XTENSA_CALL0_ABI__
 	.align	4
 	.global	__xtensa_libgcc_window_spill
 	.type	__xtensa_libgcc_window_spill,@function
@@ -38,6 +39,7 @@ __xtensa_libgcc_window_spill:
 	syscall
 	retw
 	.size	__xtensa_libgcc_window_spill, .-__xtensa_libgcc_window_spill
+#endif
 
 
 /* __xtensa_nonlocal_goto: This code does all the hard work of a
@@ -51,6 +53,7 @@ __xtensa_libgcc_window_spill:
   This function never returns to its caller but instead goes directly
   to the address of the specified goto handler.  */
 
+#if XCHAL_HAVE_WINDOWED && !__XTENSA_CALL0_ABI__
 	.align	4
 	.global	__xtensa_nonlocal_goto
 	.type	__xtensa_nonlocal_goto,@function
@@ -128,6 +131,7 @@ __xtensa_nonlocal_goto:
 
 	retw
 	.size	__xtensa_nonlocal_goto, .-__xtensa_nonlocal_goto
+#endif
 
 
 /* __xtensa_sync_caches: This function is called after writing a trampoline
@@ -154,7 +158,9 @@ __xtensa_nonlocal_goto:
 	.global	__xtensa_sync_caches
 	.type	__xtensa_sync_caches,@function
 __xtensa_sync_caches:
+#if XCHAL_HAVE_WINDOWED && !__XTENSA_CALL0_ABI__
 	entry 	sp, 32
+#endif
 #if XCHAL_DCACHE_SIZE > 0
 	/* Flush the trampoline from the data cache.  */
 	extui	a4, a2, 0, XCHAL_DCACHE_LINEWIDTH
@@ -182,5 +188,9 @@ __xtensa_sync_caches:
 	bnez	a4, .Licache_loop
 #endif
 	isync
+#if XCHAL_HAVE_WINDOWED && !__XTENSA_CALL0_ABI__
 	retw
+#else
+	ret
+#endif
 	.size	__xtensa_sync_caches, .-__xtensa_sync_caches
diff --git a/libgcc/config/xtensa/linux-unwind.h b/libgcc/config/xtensa/linux-unwind.h
index eed3be5cdce..9daf738ff57 100644
--- a/libgcc/config/xtensa/linux-unwind.h
+++ b/libgcc/config/xtensa/linux-unwind.h
@@ -52,6 +52,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define ENTRY_BYTE 0x36
 #endif
 
+#ifdef __XTENSA_WINDOWED_ABI__
 #define MD_FALLBACK_FRAME_STATE_FOR xtensa_fallback_frame_state
 
 static _Unwind_Reason_Code
@@ -94,4 +95,6 @@ xtensa_fallback_frame_state (struct _Unwind_Context *context,
   return _URC_NO_REASON;
 }
 
+#endif /* __XTENSA_WINDOWED_ABI__ */
+
 #endif /* ifdef inhibit_libc  */
diff --git a/libgcc/config/xtensa/t-windowed b/libgcc/config/xtensa/t-windowed
new file mode 100644
index 00000000000..7d9e9db0487
--- /dev/null
+++ b/libgcc/config/xtensa/t-windowed
@@ -0,0 +1,2 @@
+LIB2ADDEH = $(srcdir)/config/xtensa/unwind-dw2-xtensa.c \
+   $(srcdir)/unwind-dw2-fde.c $(srcdir)/unwind-sjlj.c $(srcdir)/unwind-c.c
diff --git a/libgcc/config/xtensa/t-xtensa b/libgcc/config/xtensa/t-xtensa
index 27399e67fa0..ed3eb84a71b 100644
--- a/libgcc/config/xtensa/t-xtensa
+++ b/libgcc/config/xtensa/t-xtensa
@@ -11,6 +11,3 @@ LIB1ASMFUNCS = _mulsi3 _divsi3 _modsi3 _udivsi3 _umodsi3 \
 	_truncdfsf2 _extendsfdf2
 
 LIB2ADD = $(srcdir)/config/xtensa/lib2funcs.S
-
-LIB2ADDEH = $(srcdir)/config/xtensa/unwind-dw2-xtensa.c \
-   $(srcdir)/unwind-dw2-fde.c $(srcdir)/unwind-sjlj.c $(srcdir)/unwind-c.c