rs6000-common.c (TARGET_SUPPORTS_SPLIT_STACK): Define.

gcc/
	* common/config/rs6000/rs6000-common.c (TARGET_SUPPORTS_SPLIT_STACK):
	Define.
	(rs6000_supports_split_stack): New function.
	* gcc/config/rs6000/rs6000.c (machine_function): Add
	split_stack_arg_pointer.
	(TARGET_EXTRA_LIVE_ON_ENTRY, TARGET_INTERNAL_ARG_POINTER): Define.
	(setup_incoming_varargs): Use crtl->args.internal_arg_pointer
	rather than virtual_incoming_args_rtx.
	(rs6000_va_start): Likewise.
	(split_stack_arg_pointer_used_p): New function.
	(rs6000_emit_prologue): Set up arg pointer for -fsplit-stack.
	(morestack_ref): New var.
	(gen_add3_const, rs6000_expand_split_stack_prologue,
	rs6000_internal_arg_pointer, rs6000_live_on_entry,
	rs6000_split_stack_space_check): New functions.
	(rs6000_elf_file_end): Call file_end_indicate_split_stack.
	* gcc/config/rs6000/rs6000.md (UNSPEC_STACK_CHECK): Define.
	(UNSPECV_SPLIT_STACK_RETURN): Define.
	(split_stack_prologue, load_split_stack_limit,
	load_split_stack_limit_di, load_split_stack_limit_si,
	split_stack_return, split_stack_space_check): New expands and insns.
	* gcc/config/rs6000/rs6000-protos.h
	(rs6000_expand_split_stack_prologue): Declare.
	(rs6000_split_stack_space_check): Declare.
libgcc/
	* config/rs6000/morestack.S: New.
	* config/rs6000/t-stack-rs6000: New.
	* config.host (powerpc*-*-linux*): Add t-stack and t-stack-rs6000
	to tmake_file.
	* generic-morestack.c: Don't build for powerpc 32-bit.

From-SVN: r223426

2 files changed, 353 insertions, 0 deletions

diff --git a/libgcc/config/rs6000/morestack.S b/libgcc/config/rs6000/morestack.S
new file mode 100644
index 0000000..ecd1bf4
--- /dev/null
+++ b/libgcc/config/rs6000/morestack.S
@@ -0,0 +1,351 @@
+#ifdef __powerpc64__
+# PowerPC64 support for -fsplit-stack.
+# Copyright (C) 2009-2015 Free Software Foundation, Inc.
+# Contributed by Alan Modra <amodra@gmail.com>.
+
+# This file is part of GCC.
+
+# GCC is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation; either version 3, or (at your option) any later
+# version.
+
+# GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+
+# Under Section 7 of GPL version 3, you are granted additional
+# permissions described in the GCC Runtime Library Exception, version
+# 3.1, as published by the Free Software Foundation.
+
+# You should have received a copy of the GNU General Public License and
+# a copy of the GCC Runtime Library Exception along with this program;
+# see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+# <http://www.gnu.org/licenses/>.
+
+#if _CALL_ELF == 2
+	.abiversion 2
+#define PARAMS 32
+#else
+	.abiversion 1
+#define PARAMS 48
+#endif
+#define MORESTACK_FRAMESIZE	(PARAMS+96)
+#define PARAMREG_SAVE		-MORESTACK_FRAMESIZE+PARAMS+0
+#define STATIC_CHAIN_SAVE	-MORESTACK_FRAMESIZE+PARAMS+64
+#define R29_SAVE		-MORESTACK_FRAMESIZE+PARAMS+72
+#define LINKREG_SAVE		-MORESTACK_FRAMESIZE+PARAMS+80
+#define NEWSTACKSIZE_SAVE	-MORESTACK_FRAMESIZE+PARAMS+88
+
+# Excess space needed to call ld.so resolver for lazy plt
+# resolution.  Go uses sigaltstack so this doesn't need to
+# also cover signal frame size.
+#define BACKOFF 4096
+# Large excess allocated when calling non-split-stack code.
+#define NON_SPLIT_STACK 0x100000
+
+
+#if _CALL_ELF == 2
+
+#define BODY_LABEL(name) name
+
+#define ENTRY0(name)					\
+	.global name;					\
+	.hidden	name;					\
+	.type name,@function;				\
+name##:
+
+#define ENTRY(name)					\
+	ENTRY0(name);					\
+0:	addis %r2,%r12,.TOC.-0b@ha;			\
+        addi %r2,%r2,.TOC.-0b@l;			\
+	.localentry name, .-name
+
+#else
+
+#define BODY_LABEL(name) .L.##name
+
+#define ENTRY0(name)					\
+	.global name;					\
+	.hidden	name;					\
+	.type name,@function;				\
+	.pushsection ".opd","aw";			\
+	.p2align 3;					\
+name##: .quad BODY_LABEL (name), .TOC.@tocbase, 0;	\
+	.popsection;					\
+BODY_LABEL(name)##:
+
+#define ENTRY(name) ENTRY0(name)
+
+#endif
+
+#define SIZE(name) .size name, .-BODY_LABEL(name)
+
+
+	.text
+# Just like __morestack, but with larger excess allocation
+ENTRY0(__morestack_non_split)
+.LFB1:
+	.cfi_startproc
+# We use a cleanup to restore the tcbhead_t.__private_ss if
+# an exception is thrown through this code.
+#ifdef __PIC__
+	.cfi_personality 0x9b,DW.ref.__gcc_personality_v0
+	.cfi_lsda 0x1b,.LLSDA1
+#else
+	.cfi_personality 0x3,__gcc_personality_v0
+	.cfi_lsda 0x3,.LLSDA1
+#endif
+# LR is already saved by the split-stack prologue code.
+# We may as well have the unwinder skip over the call in the
+# prologue too.
+	.cfi_offset %lr,16
+
+	addis %r12,%r12,-NON_SPLIT_STACK@h
+	SIZE (__morestack_non_split)
+# Fall through into __morestack
+
+
+# This function is called with non-standard calling conventions.
+# On entry, r12 is the requested stack pointer.  One version of the
+# split-stack prologue that calls __morestack looks like
+#	ld %r0,-0x7000-64(%r13)
+#	addis %r12,%r1,-allocate@ha
+#	addi %r12,%r12,-allocate@l
+#	cmpld %r12,%r0
+#	bge+ enough
+#	mflr %r0
+#	std %r0,16(%r1)
+#	bl __morestack
+#	ld %r0,16(%r1)
+#	mtlr %r0
+#	blr
+# enough:
+# The normal function prologue follows here, with a small addition at
+# the end to set up the arg pointer.  The arg pointer is set up with:
+#	addi %r12,%r1,offset
+#	bge %cr7,.+8
+#	mr %r12,%r29
+#
+# Note that the lr save slot 16(%r1) has already been used.
+# r3 thru r11 possibly contain arguments and a static chain
+# pointer for the function we're calling, so must be preserved.
+# cr7 must also be preserved.
+
+ENTRY0(__morestack)
+# Save parameter passing registers, our arguments, lr, r29
+# and use r29 as a frame pointer.
+	std %r3,PARAMREG_SAVE+0(%r1)
+	sub %r3,%r1,%r12		# calculate requested stack size
+	mflr %r12
+	std %r4,PARAMREG_SAVE+8(%r1)
+	std %r5,PARAMREG_SAVE+16(%r1)
+	std %r6,PARAMREG_SAVE+24(%r1)
+	std %r7,PARAMREG_SAVE+32(%r1)
+	addi %r3,%r3,BACKOFF
+	std %r8,PARAMREG_SAVE+40(%r1)
+	std %r9,PARAMREG_SAVE+48(%r1)
+	std %r10,PARAMREG_SAVE+56(%r1)
+	std %r11,STATIC_CHAIN_SAVE(%r1)
+	std %r29,R29_SAVE(%r1)
+	std %r12,LINKREG_SAVE(%r1)
+	std %r3,NEWSTACKSIZE_SAVE(%r1)	# new stack size
+	mr %r29,%r1
+	.cfi_offset %r29,R29_SAVE
+	.cfi_def_cfa_register %r29
+	stdu %r1,-MORESTACK_FRAMESIZE(%r1)
+
+	# void __morestack_block_signals (void)
+	bl __morestack_block_signals
+
+	# void *__generic_morestack (size_t *pframe_size,
+	#			     void *old_stack,
+	#			     size_t param_size)
+	addi %r3,%r29,NEWSTACKSIZE_SAVE
+	mr %r4,%r29
+	li %r5,0			# no copying from old stack
+	bl __generic_morestack
+
+# Start using new stack
+	stdu %r29,-32(%r3)		# back-chain
+	mr %r1,%r3
+
+# Set __private_ss stack guard for the new stack.
+	ld %r12,NEWSTACKSIZE_SAVE(%r29)	# modified size
+	addi %r3,%r3,BACKOFF-32
+	sub %r3,%r3,%r12
+# Note that a signal frame has $pc pointing at the instruction
+# where the signal occurred.  For something like a timer
+# interrupt this means the instruction has already executed,
+# thus the region starts at the instruction modifying
+# __private_ss, not one instruction after.
+.LEHB0:
+	std %r3,-0x7000-64(%r13)	# tcbhead_t.__private_ss
+
+	# void __morestack_unblock_signals (void)
+	bl __morestack_unblock_signals
+
+# Set up for a call to the target function, located 3
+# instructions after __morestack's return address.
+#
+	ld %r12,LINKREG_SAVE(%r29)
+	ld %r3,PARAMREG_SAVE+0(%r29)	# restore arg regs
+	ld %r4,PARAMREG_SAVE+8(%r29)
+	ld %r5,PARAMREG_SAVE+16(%r29)
+	ld %r6,PARAMREG_SAVE+24(%r29)
+	ld %r7,PARAMREG_SAVE+32(%r29)
+	ld %r8,PARAMREG_SAVE+40(%r29)
+	ld %r9,PARAMREG_SAVE+48(%r29)
+	addi %r0,%r12,12		# add 3 instructions
+	ld %r10,PARAMREG_SAVE+56(%r29)
+	ld %r11,STATIC_CHAIN_SAVE(%r29)
+	cmpld %cr7,%r12,%r0		# indicate we were called
+	mtctr %r0
+	bctrl				# call caller!
+
+# On return, save regs possibly used to return a value, and
+# possibly trashed by calls to __morestack_block_signals,
+# __generic_releasestack and __morestack_unblock_signals.
+# Assume those calls don't use vector or floating point regs.
+	std %r3,PARAMREG_SAVE+0(%r29)
+	std %r4,PARAMREG_SAVE+8(%r29)
+	std %r5,PARAMREG_SAVE+16(%r29)
+	std %r6,PARAMREG_SAVE+24(%r29)
+#if _CALL_ELF == 2
+	std %r7,PARAMREG_SAVE+32(%r29)
+	std %r8,PARAMREG_SAVE+40(%r29)
+	std %r9,PARAMREG_SAVE+48(%r29)
+	std %r10,PARAMREG_SAVE+56(%r29)
+#endif
+
+	bl __morestack_block_signals
+
+	# void *__generic_releasestack (size_t *pavailable)
+	addi %r3,%r29,NEWSTACKSIZE_SAVE
+	bl __generic_releasestack
+
+# Reset __private_ss stack guard to value for old stack
+	ld %r12,NEWSTACKSIZE_SAVE(%r29)
+	addi %r3,%r3,BACKOFF
+	sub %r3,%r3,%r12
+.LEHE0:
+	std %r3,-0x7000-64(%r13)	# tcbhead_t.__private_ss
+
+	bl __morestack_unblock_signals
+
+# Use old stack again.
+	mr %r1,%r29
+
+# Restore return value regs, and return.
+	ld %r0,LINKREG_SAVE(%r29)
+	mtlr %r0
+	ld %r3,PARAMREG_SAVE+0(%r29)
+	ld %r4,PARAMREG_SAVE+8(%r29)
+	ld %r5,PARAMREG_SAVE+16(%r29)
+	ld %r6,PARAMREG_SAVE+24(%r29)
+#if _CALL_ELF == 2
+	ld %r7,PARAMREG_SAVE+32(%r29)
+	ld %r8,PARAMREG_SAVE+40(%r29)
+	ld %r9,PARAMREG_SAVE+48(%r29)
+	ld %r10,PARAMREG_SAVE+56(%r29)
+#endif
+	ld %r29,R29_SAVE(%r29)
+	.cfi_def_cfa_register %r1
+	blr
+
+# This is the cleanup code called by the stack unwinder when
+# unwinding through code between .LEHB0 and .LEHE0 above.
+cleanup:
+	.cfi_def_cfa_register %r29
+	std %r3,PARAMREG_SAVE(%r29)	# Save exception header
+	# size_t __generic_findstack (void *stack)
+	mr %r3,%r29
+	bl __generic_findstack
+	sub %r3,%r29,%r3
+	addi %r3,%r3,BACKOFF
+	std %r3,-0x7000-64(%r13)	# tcbhead_t.__private_ss
+	ld %r3,PARAMREG_SAVE(%r29)
+	bl _Unwind_Resume
+	nop
+	.cfi_endproc
+	SIZE (__morestack)
+
+
+	.section .gcc_except_table,"a",@progbits
+	.p2align 2
+.LLSDA1:
+	.byte	0xff	# @LPStart format (omit)
+	.byte	0xff	# @TType format (omit)
+	.byte	0x1	# call-site format (uleb128)
+	.uleb128 .LLSDACSE1-.LLSDACSB1	# Call-site table length
+.LLSDACSB1:
+	.uleb128 .LEHB0-.LFB1	# region 0 start
+	.uleb128 .LEHE0-.LEHB0	# length
+	.uleb128 cleanup-.LFB1	# landing pad
+	.uleb128 0		# no action, ie. a cleanup
+.LLSDACSE1:
+
+
+#ifdef __PIC__
+# Build a position independent reference to the personality function.
+	.hidden DW.ref.__gcc_personality_v0
+	.weak DW.ref.__gcc_personality_v0
+	.section .data.DW.ref.__gcc_personality_v0,"awG",@progbits,DW.ref.__gcc_personality_v0,comdat
+	.p2align 3
+DW.ref.__gcc_personality_v0:
+	.quad __gcc_personality_v0
+	.type DW.ref.__gcc_personality_v0, @object
+	.size DW.ref.__gcc_personality_v0, 8
+#endif
+
+
+	.text
+# Initialize the stack guard when the program starts or when a
+# new thread starts.  This is called from a constructor.
+# void __stack_split_initialize (void)
+ENTRY(__stack_split_initialize)
+	addi %r3,%r1,-0x4000		# We should have at least 16K.
+	std %r3,-0x7000-64(%r13)	# tcbhead_t.__private_ss
+	# void __generic_morestack_set_initial_sp (void *sp, size_t len)
+	mr %r3,%r1
+	li %r4, 0x4000
+	b __generic_morestack_set_initial_sp
+	SIZE (__stack_split_initialize)
+
+
+# Return current __private_ss
+# void *__morestack_get_guard (void)
+ENTRY0(__morestack_get_guard)
+	ld %r3,-0x7000-64(%r13)		# tcbhead_t.__private_ss
+	blr
+	SIZE (__morestack_get_guard)
+
+
+# Set __private_ss
+# void __morestack_set_guard (void *ptr)
+ENTRY0(__morestack_set_guard)
+	std %r3,-0x7000-64(%r13)	# tcbhead_t.__private_ss
+	blr
+	SIZE (__morestack_set_guard)
+
+
+# Return the stack guard value for given stack
+# void *__morestack_make_guard (void *stack, size_t size)
+ENTRY0(__morestack_make_guard)
+	sub %r3,%r3,%r4
+	addi %r3,%r3,BACKOFF
+	blr
+	SIZE (__morestack_make_guard)
+
+
+# Make __stack_split_initialize a high priority constructor.
+	.section .ctors.65535,"aw",@progbits
+	.p2align 3
+	.quad __stack_split_initialize
+	.quad __morestack_load_mmap
+
+	.section .note.GNU-stack,"",@progbits
+	.section .note.GNU-split-stack,"",@progbits
+	.section .note.GNU-no-split-stack,"",@progbits
+#endif /* __powerpc64__ */
diff --git a/libgcc/config/rs6000/t-stack-rs6000 b/libgcc/config/rs6000/t-stack-rs6000
new file mode 100644
index 0000000..0690622
--- /dev/null
+++ b/libgcc/config/rs6000/t-stack-rs6000
@@ -0,0 +1,2 @@
+# Makefile fragment to support -fsplit-stack for powerpc.
+LIB2ADD_ST += $(srcdir)/config/rs6000/morestack.S