common.opt (fsplit-stack): New option.

gcc/:
	* common.opt (fsplit-stack): New option.
	* opts.c (decode_options): Set flag_split_stack to final value.
	* target.def (supports_split_stack): New hook.
	* gcc.c (STACK_SPLIT_SPEC): Define.
	(LINK_COMMAND_SPEC): Use STACK_SPLIT_SPEC.
	* doc/invoke.texi (Option Summary): Mention -fsplit-stack.
	(Code Gen Options): Document -fsplit-stack.
	* doc/extend.texi (Function Attributes): Mention no_split_stack.
	(Function Attributes): Document no_split_stack.
	* doc/tm.texi.in (Stack Smashing Protection): Add @hook
	TARGET_SUPPORTS_SPLIT_STACK.
	* doc/tm.texi: Rebuild.
	* function.c (thread_prologue_and_epilogue_insns): If
	flag_split_stack, add split stack prologue.
	* explow.c (allocate_dynamic_stack_space): Support -fsplit-stack.
	* varasm.c (saw_no_split_stack): New static variable.
	(assemble_start_function): Set saw_no_split_stack if the function
	has the no_split_stack attribute.
	(file_end_indicate_split_stack): New function.
	* output.h (file_end_indicate_split_stack): Declare.
	* libgcc-std.ver (GCC_4.6.0): Add -fsplit-stack support variables
	and function.
	* doc/libgcc.texi (Miscellaneous routines): Document -fsplit-stack
	routines.
	* config/i386/i386.c (ix86_option_override_internal): Don't set
	expand_builtin_va_start to NULL if -fsplit-stack.
	(ix86_function_regparm): Reduce local regparm by 1 for 32-bit
	-fsplit-stack.
	(ix86_va_start): If -fsplit-stack, get overflow pointer	from
	scratch register set by prologue.
	(ix86_code_end): If -fsplit-stack, call
	file_end_indicate_split_stack.
	(ix86_supports_split_stack): New static function.
	(SPLIT_STACK_AVAILABLE): Define.
	(split_stack_prologue_scratch_regno): New static function.
	(split_stack_fn): New static variable.
	(ix86_expand_split_stack_prologue): New function.
	(ix86_live_on_entry): New static function.
	(ix86_legitimate_address_p): Handle UNSPEC_STACK_CHECK.
	(output_pic_addr_const): Likewise.
	(i386_asm_output_addr_const_extra): Likewise.
	(ix86_expand_call): Change return type to rtx.  Return the new
	call instruction.
	(TARGET_SUPPORTS_SPLIT_STACK): Define.
	(TARGET_EXTRA_LIVE_ON_ENTRY): Define.
	* config/i386/i386.md (UNSPEC_STACK_CHECK): Define.
	(split_stack_prologue, split_stack_return): New insns.
	(split_stack_space_check): New insn.
	* config/i386/i386.h (struct machine_function): Add
	split_stack_varargs_pointer field.
	* config/i386/linux.h (TARGET_CAN_SPLIT_STACK): Define.
	(TARGET_THREAD_SPLIT_STACK_OFFSET): Define.
	* config/i386/linux64.h (TARGET_CAN_SPLIT_STACK): Define.
	(TARGET_THREAD_SPLIT_STACK_OFFSET): Define.
	* config/i386/i386-protos.h (ix86_expand_split_stack_prologue):
	Declare.
	(ix86_expand_call): Update declaration.
gcc/c-family/:
	* c-common.c (c_common_attribute_table): Add no_split_stack.
	(handle_no_split_stack_attribute): New static function.
gcc/testsuite/:
	* lib/target-supports.exp (check_effective_target_split_stack):
	New procedure.
	* gcc.dg/split-1.c: New test.
	* gcc.dg/split-2.c: New test.
	* gcc.dg/split-3.c: New test.
	* gcc.dg/split-4.c: New test.
libgcc/:
	* generic-morestack.h: New file.
	* generic-morestack.c: New file.
	* generic-morestack-thread.c: New file.
	* config/i386/morestack.S: New file.
	* config/t-stack: New file.
	* config/i386/t-stack-i386: New file.
	* config.host (i[34567]86-*-linux* and friends): Add t-stack and
	i386/t-stack-i386 to tmake_file.

From-SVN: r164661

1 files changed, 43 insertions, 15 deletions

diff --git a/gcc/function.c b/gcc/function.c
index a11f248..04a2ebc 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -5214,17 +5214,50 @@ emit_return_into_block (basic_block bb)
 static void
 thread_prologue_and_epilogue_insns (void)
 {
-  int inserted = 0;
+  bool inserted;
+  rtx seq, epilogue_end;
+  edge entry_edge;
   edge e;
-#if defined (HAVE_sibcall_epilogue) || defined (HAVE_epilogue) || defined (HAVE_return) || defined (HAVE_prologue)
-  rtx seq;
-#endif
-#if defined (HAVE_epilogue) || defined(HAVE_return)
-  rtx epilogue_end = NULL_RTX;
-#endif
   edge_iterator ei;
 
   rtl_profile_for_bb (ENTRY_BLOCK_PTR);
+
+  inserted = false;
+  seq = NULL_RTX;
+  epilogue_end = NULL_RTX;
+
+  /* Can't deal with multiple successors of the entry block at the
+     moment.  Function should always have at least one entry
+     point.  */
+  gcc_assert (single_succ_p (ENTRY_BLOCK_PTR));
+  entry_edge = single_succ_edge (ENTRY_BLOCK_PTR);
+
+  if (flag_split_stack
+      && (lookup_attribute ("no_split_stack", DECL_ATTRIBUTES (cfun->decl))
+	  == NULL))
+    {
+#ifndef HAVE_split_stack_prologue
+      gcc_unreachable ();
+#else
+      gcc_assert (HAVE_split_stack_prologue);
+
+      start_sequence ();
+      emit_insn (gen_split_stack_prologue ());
+      seq = get_insns ();
+      end_sequence ();
+
+      record_insns (seq, NULL, &prologue_insn_hash);
+      set_insn_locators (seq, prologue_locator);
+
+      /* This relies on the fact that committing the edge insertion
+	 will look for basic blocks within the inserted instructions,
+	 which in turn relies on the fact that we are not in CFG
+	 layout mode here.  */
+      insert_insn_on_edge (seq, entry_edge);
+      inserted = true;
+#endif
+    }
+
 #ifdef HAVE_prologue
   if (HAVE_prologue)
     {
@@ -5251,13 +5284,8 @@ thread_prologue_and_epilogue_insns (void)
       end_sequence ();
       set_insn_locators (seq, prologue_locator);
 
-      /* Can't deal with multiple successors of the entry block
-         at the moment.  Function should always have at least one
-         entry point.  */
-      gcc_assert (single_succ_p (ENTRY_BLOCK_PTR));
-
-      insert_insn_on_edge (seq, single_succ_edge (ENTRY_BLOCK_PTR));
-      inserted = 1;
+      insert_insn_on_edge (seq, entry_edge);
+      inserted = true;
     }
 #endif
 
@@ -5427,7 +5455,7 @@ thread_prologue_and_epilogue_insns (void)
       end_sequence ();
 
       insert_insn_on_edge (seq, e);
-      inserted = 1;
+      inserted = true;
     }
   else
 #endif